SEPA
         United States
         Environmental Protection
         Agency
         Industrial Environmental Research  EPA-600/7-79-098b
         Laboratory         April 1979
         Research Triangle Park NC 27711
Proceedings: Symposium
on Coal Cleaning to
Achieve Energy and
Environmental Goals
(September 1978,
Hollywood, FL) -
Volume II

Interagency
Energy/Environment
R&D Program  Report

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                 RESEARCH REPORTING SERIES


Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination  of  traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:

    1. Environmental Health Effects Research

    2. Environmental Protection Technology

    3. Ecological Research

    4. Environmental Monitoring

    5. Socioeconomic Environmental Studies

    6. Scientific and Technical Assessment Reports (STAR)

    7. Interagency Energy-Environment Research and Development

    8. "Special" Reports

    9. Miscellaneous Reports

This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND  DEVELOPMENT  series. Reports in this series  result from the
effort funded  under  the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects;  assessments of, and  development of, control technologies for energy
systems; and integrated assessments of a wide range of energy-related environ-
mental issues.
                       EPA REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
for publication. Approval does not signify that the contents necessarily reflect
the views and policies of the Government, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.

This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                 EPA-600/7-79-098b

                                          April 1979
Proceedings:  Symposium on Coal
    Cleaning to Achieve Energy
      and Environmental Goals
 (September  1978, Hollywood, FL) -
                 Volume II
                      by

           S.E. Rogers and A.W. Lemmon, Jr. (Editors)

              Battelle Columbus Laboratories
                  505 King Avenue
                Columbus, Ohio 43201
                Contract No. 68-02-2163
                   Task No. 861
              Program Element No. EHE624A
             EPA Project Officer: James D. Kilgroe

           Industrial Environmental Research Laboratory
            Office of Energy, Minerals, and Industry
              Research Triangle Park, NC 27711
                   Prepared for

          U.S. ENVIRONMENTAL PROTECTION AGENCY
             Office of Research and Development
                Washington, DC 20460

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                              ABSTRACT
     The Symposium on Coal Cleaning to Achieve Energy and Environmental Goals
was sponsored by the U.S. EPA's Industrial Environmental Research Laboratory
under Contract No. 68-02-2163, Task No. 861.   The Symposium was held September
11-15, 1978, in Hollywood, Florida.  The program provided an opportunity
for mutual review and discussion of the physical and chemical coal cleaning
programs of EPA, DoE, the Electric Power Research Institute, those of
numerous industrial organizations, and European and Soviet plans for the
future, as well as the problems of ongoing operations.

     The Proceedings contain the contributions of the participating speakers
and include the following topics:

     (a)  Coal Characteristics
     (b)  Coal Cleaning Overview
     (c)  Physical Coal Cleaning Technology
     (d)  Environmental Assessment and Pollution Control Technology
     (e)  Chemical Coal Cleaning Technology.
                                   ii

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                               FOREWORD

     Man and his environment must be protected from the adverse  effects  of
pesticides, radiation, noise, industrial effluents, and other forms  of
pollution, as well as the unwise management  of solid waste.   Efforts to
protect the environment require a focus that recognizes the  interplay among
the components of our physical and biological environment—air,  water, land,
plants, and animals.  The Industrial Environmental Research  Laboratory  (IERL/
RTF) of the U.S. Environmental Protection Agency (EPA)  located at Research
Triangle Park, North Carolina, contributes to this multidisciplinary focus
through programs engaged in:
     •  studies on the effects of environmental contaminants on
        the biosphere, and
     •  a search for ways to prevent contamination and  to recycle
        valuable resources.
     This Symposium Proceedings deals with the subject  matter of concern to
an IERL/RTP program designed to focus on the effectiveness and efficiency of
coal cleaning processes as a means of reducing the total environmental  impact
of energy production through coal utilization.  The Symposium itself provided
a most vital communication link between the  researcher  and engineer  on  the
one hand and the user community on the other.  To enhance future communica-
tion processes and encourage future applications of coal cleaning technology,
this Symposium Proceedings documents the results of the meeting  held.
                                 iii

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                           ACKNOWLEDGMENT

     No symposium can be a success without  the support and participation of
the attendees.   For those participants listed elsewhere  in this  document,
then, we are grateful for their contributions.  Thanks in full measure  is
due also to the Session Chairmen and Cochairmen  who patiently  labored to
formulate an informative and timely program.   And,  of course,  none  of this
would have been possible without the long hours  spent by the authors indivi-
dually and collectively, in the preparation of their papers.
     Thanks are also due for the handling of the mechanical  details of  the
Symposium.  These necessary functions were performed ably by a number of
people.  Mr. Jack H. Greene (IERL/RTP) was responsible for  the overall
arrangements with the hotel, and Ms. Susan R. Armstrong, Conference Coor-
dinator at Battelle's Columbus Laboratories (BCL),  managed  the day-to-day
activities.  She was assisted in the many details of the necessary operations
by Ms. Joyce B. Fowler  (IERL/RTP), Mrs. Rebecca  S.  Miller (BCL), and Mrs.  Lucy
G. Pierson  (BCL).
      Special thanks are expressed  to Mrs. Alexis W. Lemmon, Jr., and
Mrs.  L. David Tamny for their efforts in making the week more pleasant
for  the distaff accompaniers of the Symposium participants.
      In the preparation of  the printed Symposium Proceedings, Ms.  Sharron
E. Rogers performed excellently as Technical  Editor.  Mrs. Miller  and
Mrs.  Pierson organized, formatted, and provided the necessary typing.  We
are  grateful for  their  assistance.
                                     iv

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                              TABLE OF CONTENTS
                                                                      Page
Abstract                                                               ±±
Foreword                                                              iii
Acknowledgment                                                         iv

Final Program	   1

Conference Report and Activities	   5

                      Session 0;  Coal Characteristics

PETROGRAPHY OF COAL	   9
Ronald W. Stanton and Robert B. Finkelman
U.S. Geological Survey

MINERALOGIC.. AFFINITIES OF TRACE ELEMENTS IN COAL	29
F. L. Fiene , J. K. Kuhn , and H. J. Gluskoter
 Illinois State Geological Survey
2
 Exxon Production Research Company

EFFECTS OF COAL CLEANING ON ELEMENTAL DISTRIBUTIONS 	  59
Charles T. Ford and James F. Boyer
Bituminous Coal Research, Inc.

PARTICLE SIZE DISTRIBUTION IN THE LIBERATION OF PYRITE IN COAL  ...  91
Harold L. Lovell
The Pennsylvania State University

GEOLOGIC CONTROLS ON MINERAL MATTER IN THE
UPPER FREEPORT COAL BED	HO
C. B. Cecil, R. W. Stanton, S. D. Allshouse, and R. B. Finkelman
U.S. Geological Survey

INTERPRETING STATISTICAL VARIABILITY  	 126
Ralph E. Thomas
Battelle's Columbus Laboratories

                     Session 1;  Coal Cleaning Overview

AN OVERVIEW OF EPA COAL CLEANING PROGRAMS	149
J. D. Kilgroe and D. A. Kirchgessner
U.S. EPA, IERL-RTP

OVERVIEW OF DOE COAL CLEANING PROGRAM	171
Cyril W. Draffin
U.S. Department of Energy

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                              TABLE OF CONTENTS
                                 (Continued)
                                                                      Page
OVERVIEW OF EPRI COAL CLEANING PROGRAMS	,	194
Kenneth Clifford and Shelton Ehrlich
Electric Power Research Institute

AN INTEGRATED ASSESSMENT OF GOAL TECHNOLOGIES	!95
Richard S. Davidson
Battelle's Columbus Laboratories

THE MAIN TRENDS OF WORKS ON ENVIRONMENTAL PROTECTION
AGAINST THE INFLUENCE OF COAL-PREPARATION PLANTS  IN THE USSR  ....  207
I. S.  Blagov, G. G. Vosnyuk, V. V, Kochetov,
I. Ch. Nekhoroshy, and  I.  E. Cherevko
USSR Ministry of Coal Industry

THE CLEAN FUEL SUPPLY:  FACTORS AFFECTING U.S. AND EUROPEAN
SO, EMISSIONS IN THE MID-19801 s	228
Anthony Bromley and Gary J.  Foley
Organization of Economic Cooperation and Development

A TECHNICAL AND ECONOMIC OVERVIEW  OF CDAL CLEANING	256
Horst Huettenhain, Jackson Yu,  and Samuel Wong
 Bechtel  National,  Inc.  and Argonne National Laboratory

OVERCOMING THE BARRIERS TO INVESTMENT IN PHYSICAL COAL
CLEANING WITH REVISED NSPS FOR  UTILITY BOILERS	298
Karel Fisher and  Peter Cukor
 Teknekron, Inc.

 ECONOMICS  OF COAL CLEANING AND FLUE GAS DESULFURIZATION FOR
 COMPLIANCE WITH REVISED NSPS FOR UTILITY BOILERS	324
 Randy M. Cole
 Energy Research-Combustion Systems
 Tennessee Valley Authority

 THE ECONOMICS OF BENEFICIATING AND MARKETING
 HIGH-SULFUR IOWA COAL	360
 C. Phillip Baumel, John J. Miller and Thomas P. Drinka
 Department of Economics,  Iowa State University

                 Session 2;  Physical Coal Cleaning Technology

 AN EVALUATION OF THE DESULFURIZATION POTENTIAL OF U.S. COALS	387
 Jane H.  McCreery and Frederick K.  Goodman
 Battelle's Columbus Laboratories

 THE USE OF COAL CLEANING FOR COMPLYING WITH SO.
 EMISSION REGULATIONS	7	416
 Elton H. Hall and Gilbert E. Raines
 Battelle's Columbus Laboratories and
 Raines Consulting, Incorporated
                                     vi

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                              TABLE OF CONTENTS
                                 (Continued)
                                                                      Page
STATISTICAL CORRELATIONS ON COAL DESULFURIZATION BY
CRUSHING AND SPECIFIC GRAVITY SEPARATION ..............  448
Ralph E. Thomas
Battelle's Columbus Laboratories
DEWATERING AND DRYING OF FINE COAL:  EQUIPMENT
PERFORMANCE AND COSTS  .......................
Donald H. Sargent, Bill H. Cheng, and G. Yeghyazarian Contos
Versar, Inc.

HOMER CITY COAL CLEANING DEMONSTRATION, TEST, AND
TECHNOLOGY EVALUATION PROGRAM  ...................  488
James H. Tice
Pennsylvania Electric Company

COMPUTER CONTROL OF COAL PREPARATION PLANTS  .......... •  •  503
Gerry Norton, George Hambleton, and Clive Longden
Norton-Ramble ton Associates, Inc.

PHYSICAL AND PHYSIOCHEMICAL REMOVAL OF SULFUR FROM COAL  ......  519
David H. Birlingmair and Ray W. Fisher
Ames Laboratory, Iowa State University

CLEANING OF EASTERN BITUMINOUS COALS BY FINE GRINDING,
FROTH FLOTATION AND HIGH-GRADIENT MAGNETIC SEPARATION  .......  534
W. L. Freyberger, J. W. Keck, D. W. Spottiswood,
N. D. Solem and Virginia L. Doane
Michigan Technological University

THE POTENTIAL OF MAGNETIC SEPARATION ll» COAL CLEANING  .......  568
Frederick V. Karlson, Kenneth L. Clifford, William W. Slaughter,
and Horst Huettenhain
Bechtel Corporation, Electric Power Research Institute,
and Bechtel National, Inc.

TESTING OF COMMERCIAL COAL PREPARATION PLANTS
WITH A MOBILE LABORATORY  ......................  599
William Higgins and Thomas Plouf
Joy Manufacturing Company

CHEMICAL COMMINUTION— AN  IMPROVED ROUTE TO CLEAN COAL  .......  600
Victor C. Quackenbush, Robert R. Haddocks, and  George W. Higginson
Catalytic, Inc.

COAL CLEANING BY THE OTISCA PROCESS   ................  623
C. D. Smith
Otisca Industries, Ltd.
                                    vii

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                              TABLE OF CONTENTS
                                 (Continued;
                Session 3;  Environmental Assessment and
                        Pollution Control Technology
                                                                      Page
THE COAL CLEANING PROGRAM OF THE FUEL
PROCESS BRANCH OF EPA*8 IERL-RTP 	  637
T. K. Janes
U.S. Environmental Protection Agency

ENVIRONMENTAL ASSESSMENT METHODOLOGIES FOR FOSSIL
ENERGY PROCESSES:  AN UPDATE	 .  646
Robert P. Hangebrauck
U.S. Environmental Protection Agency

REVIEW OF REGULATIONS AND STANDARDS INFLUENCING COAL CLEANING  ...  683
P. Van Voris, R. A. Ewing, and J. W. Harrison
Battelle's Columbus Laboratories and Research Triangle Institute

DEVELOPMENT OF ENVIRONMENTAL ASSESSMENT CRITERIA FOR COAL
CLEANING PROCESSES 	  711
R. A. Ewing, P. Van Voris, B. Cornaby, and G. E. Raines
Battelle's Columbus Laboratories and Raines Consulting, Incorporated

APPLICATION OF ENVIRONMENTAL ASSESSMENT METHODOLOGY TO HOMER
CITY POWER COMPLEX BACKGROUND DATA:  COMPARISON WITH MEG VALUES  . .  753
D. A. Tolle, D. P. Brown, R. Clark, D. Sharp,
J. M. Stilwell, and B. W. Vlgon
Battelle's Columbus Laboratories

AN OVERVIEW OF CONTROL TECHNOLOGY  	  793
A. W. Lemmon, Jr., G. L. Robinson, and D. A. Sharp
Battelle's Columbus Laboratories

CHARACTERIZATION OF PREPARATION PLANT WASTEWATERS  	  824
K. B. Randolph, L. B. Kay, and R. C. Smith, Jr.
Versar, Inc.

CONTROL OF TRACE ELEMENT LEACHING FROM COAL PREPARATION WASTES ...  856
E. M. Wewerka, J. M. Williams, P. Wagner,
L. E. Wangen, and J. P. Bertino
Los Alamos Scientific Laboratory

STABILIZATION OF COAL PREPARATION PLANT SLUDGES  	  875
David C. Hoffman
Dravo Lime Company
                                     viii

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                               TABLE  OF  CONTENTS
                                  (Continued)
                                                                      Page
 CHEMICAL AND BIOLOGICAL  CHARACTERIZATION OP LEACHATE
 FROM COAL  CLEANING WASTES   .  ...... ....  ..........  898
 R.  M.  Schuller,  R. A.  Griffin, and J. J. Suloway
 Illinois State Geological  Survey and Illinois State
 Natural History  Survey

                     Session  4;  Chemical Coal Cleaning

 INTRODUCTION TO  CHEMICAL COAL CLEANING   ..............  923
 R.  A.  Meyers
 TRW,  Inc.

 CURRENT STATUS OF  CHEMICAL COAL CLEANING PROCESSES -
 AN  OVERVIEW   ............................  934
 L.  C.  McCandless and Mrs.  G.  Y. Contos
 Versar, Inc.

 STATUS OF  THE REACTOR  TEST PROJECT FOR CHEMICAL
 REMOVAL OF PYRITIC SULFUR  FROM COAL  ................  960
 M.  J.  Santy  and  L. J.  Van  Nice
 TRW,  Inc.

 STATUS OF  HYDROTHERMAL PROCESSING FOR CHEMICAL
 DESULFURIZATION  OF COAL  .................. ....  991
 E.  P.  Stambaugh, H. N. Conkle, J. F. Miller, E. J. Mezey and B. C. Kin
 Battelle's Columbus Laboratories

 SURVEY OF  COALS  TREATED  BY OXYEESULFURIZATION  .... ....... 1016
 R.  P.  Warzinski, J. A. Ruether, S. Friedman, and F. W. Staffgen
 U.S. Department  of Energy,  Pittsburgh Energy Technology Center

 COAL DESULFURIZATION BY  LEACHING WITH ALKALINE SOLUTIONS
 CONTAINING OXYGEN  ......................... 1039
 R. Markuszewski, K. C. Chuang, and T. D. Wheelock
 Ames Laboratory, Iowa  State University

 THE POTENTIAL FOR CHEMICAL  COAL CLEANING:   RESERVES,
 TECHNOLOGY, AND ECONOMICS   ..................... 1064
 R. A. Giberti, R. S. Opalanko, and J. R. Sinek
Kennecott  Copper Corporation and Resource Engineering, Inc.

JPL COAL DESULFURIZATION PROCESS BY
LOW TEMPERATURE CHLORINOLYSIS  ................... !096
John J. Kalvinskas and George C. Hsu
 California Institute of Technology
OXIDATIVE COAL DESULFURIZATION USING NITROGEN
OXIDES - THE KVB PROCESS
E. D. Guth
KVB, Inc.
                                        ix

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                              TABLE OF CONTENTS
                                 (Continued)

                                                                      Page

THE DRY REMOVAL OF PYRITE AND ASH FROM GOAL BY THE
MAGNEX PROCESS COAL PROPERTIES AND PROCESS VARIABLES 	  1165
James K. Kindig and Duane N. Goens
Hazen Research, Inc.

PANEL DISCUSSION ON PROSPECTS FOR CHARACTERIZATION
AND REMOVAL OR ORGANIC SULFUR FROM COAL	1197
Chairman:  Robin R. Oder; Panelists:  Sidney Freidman,
Amir Attar, Douglas M. Jewell, and Thomas G. Squires
Gulf Research and Development Co.; Pittsburgh Energy Research
Center - DOE; University of Houston; Gulf Research and
Development Co.; and Iowa State University

List of Participants	1208

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                       The Coal Cleaning Program
                       of the Fuel Process Branch
                           OF EPA's IERL-RTP

                             T. Kelly Janes
                       Chief, Fuel Process Branch
                   Industrial Environmental Research
                             Laboratory-RTP
                  U.S. Environmental Protection Agency
                     Research Triangle Park, N. C.


     EPA's Industrial Environmental Research Laboratory at Research
Triangle Park, N.C., conducts a contractual and In-house research,
development, and demonstration program dealing with the control of
emissions/discharges from energy related technologies and industrial
processes.

     The Laboratory is divided into three technical divisions:

     1.   Utilities and Industrial Power Division which primarily
          addresses the emissions controls for the combustion
          of fossil fuels to generate steam and electrical power.

     2.   Energy Assessment and Control Division which develops
          improved combustion techniques for nitrogen oxide con-
          trol, advanced combustion systems, and the environmental
          effects and control techniques for coal processing and
          conversion of coal to synthetic liquids and gases.

     3.   Industrial  Processes Division which addresses the emission
          and controls from industrial operations.  Additionally,
          in this Division, analytical and sampling techniques are
          developed.

     The Fuel Process Branch in the Energy Assessment and Control Division
conducts programs addressing two major areas:

     1.   Coal Cleaning.  Development of physical and chemical tech-
          niques to remove contaminants from coal; assessment of
          the environmental  consequences from the utilization of
          coal cleaning processes; and the development of control
          technology to avoid adverse discharge effects.

     2.   Synthetic Fuels.  The assessment of the multimedia
          discharges  and control technique evaluation for tech-
          nologies converting coal to gaseous, liquid, and refined
          solid fuels.

     Both programs deal with the multimedia (air, water, and solid)
discharge effects.  However, the coal cleaning program has the additional
responsibility to develop the basic processing technology.  In 1965,
                                  638

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EPA (and Its prior organizations) Initiated studies to determine the
applicability of physical  coal  cleaning to reduce emissions from the
combustion of coal.  Early 1n this program 1t was apparent that
additional information would be required before the assessment of
this technology could be made.   Thus, numerous projects ware Initiated
to:

     1.   Evaluate the degree of pyrlte removal which could
          be obtained from cleaning of U.S. coals.

     2.   Determine the effectiveness of comnerdal coal pre-
          paration techniques to maximize pyrlte separation.

     3.   Evaluate processes that could utilize the coal reject
          mineral matter to aid  in offsetting the  increased cost
          of coal cleaning.

     Since  then, the  coal cleaning program has passed through three
major  phases.

     Phase  I.   The development  of data  and information  which would
provide  a data  base to  assess  the applicability  of coal cleaning to
maximize  sulfur reduction.  Technical  areas  addressed during this
phase  were:

     -  Laboratory evaluation  of potential pyrlte  ash  removal
         as  affected by  size  reduction and  specific gravity.

     -  Mineral constituents of U.S.  coals.

     -  Applicability and effectiveness of existing coal  cleaning
         techniques  to maximize  pyrite separation and removal.

     -  Available  technology for recovery of economic values from
         coal  cleaning refuse.

      -  Quality and quantity of U.S. coal  reserves.

      -  Investigation and development of new or modified physical
         cleaning techniques for removal of pyrite and other con-
         taminants from coal.

      -  Design of a coal  cleaning pilot plant to evaluate cleana-
         bility of coals and performance of cleaning equipment.

      Phase II.  In the late 1960s, it became quite apparent that
 improved cleaning techniques would be necessary to increase sulfur
 removal to meet future requirements.  These methods would need to be
 basically unaffected by pyrite  size variations which have a marked
 effect on physical separation methods.  Thus, a broad evaluation of
 various chemical cleaning techniques was conducted.  Some 24 chemical
 reagents ware  evaluated for sulfur  removal  potential.  The  results
 showed that organic  sulfur removal was extremely  difficult  and that
                                   639

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the inorganic sulfur removal  potential  was much closer to realization.
Thus, the ferrous sulfate leaching process development was initiated
and carried through reactor pilot evaluation.  Additionally, evaluations
of other techniques, using hydrogen and microwave energy, were supported.
The potential effectiveness of organic sulfur removal may well depend
on prior removal of pyrite and other inorganic material.

     Phase III.  In the early 1970s, natural gas and oil shortages
became a public concern and the need to fully utilize the nation's
vast coal reserves became a federal goal.  This concern with energy
and increased use of "coal was accompanied by a parallel concern with
the potential impact that increased coal utilization would have on
the health and ecological systems of the nation.  This phase of the
EPA coal cleaning program is concentrating on the Identification of
environmental impacts of discharges by using both chemical and
biological evaluations.

     The ongoing program covers a wide spectrum of activities from
coal contaminant variability through evaluation of effects that clean
coal will have on existing controls for combustion waste gas.

     During this symposium, details of these ongoing efforts will be
dealt with.

     The reports listed on the following pages were prepared under
the sponsorship and direction of IERL-RTP.  For convenience these
reports  are listed under the following categories:  coal characterization,
evaluation of coal cleaning techniques, coal reject treatments, coal
cleaning prototype plant, chemical coal cleaning, and applicability
studies.
                                  640

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                          EPA/IERL-RTP REPORTS
Contractor
(Contract No,)
NTIS No.
(EPA No.)
Coal Characterization
Illinois State
Geological Survey
(PH 86-67-206)
U.S. Bureau of
Mines

U.S. Bureau of
Mines
Exxon
(68-02-0629)

Illinois State
Geological Survey
(68-02-0246)

U.S. Bureau of
Mines
(IAG-P5-0685)

Los Alamos Scien.
Lab (IAG-D5-E681)
Illinois State
Geological Survey
(68-02-1472)

Los Alamos Scien.
Lab (IAG-D5-E681)
U.S. Dept. of
Energy
(IAG DXE685-W)
PB 206-464
(APTD 0915)
                    PB 205-952
                    (APTD 0841)
RI 7633
(APTD 1365)

RI 7608
PB 225-039/7AS
EPA-R2-73-249

PB 238-091/AS
EPA-650/2-74-
054

PB 252-965/AS
EPA-600/2-76-
091

PB 267-339/AS
EPA-600/7-75-
007

PB 270-922/AS
EPA-600/7-77-
064

LA-6835-PR
EPA-600/7-78-
028

PB 280-759/AS
EPA-600/7-78-
038
Report Title -- Date Pufa1ished(No. of Pages)
Sulfur varieties in Illinois coals float
sink tests (final  phase I) -- 8/69
(98 pp)

Sulfur reduction of Illinois coal washa-
bility studies (final  phase II) — 8/69
(98 pp)

Sulfur reduction potential of the coals
of the U.S. - 1972 (304 pp)

Washability examinations of core samples
of San Juan Basin coals, New Mexico and
Colorado -- 1972 (30 pp)

Potential pollutants in fossil  fuels --
6/73 (293 pp)

Occurrence and distribution of potentially
volatile trace elements in coal -- 7/74
(106 pp)

Sulfur reduction potential of U.S. coals:
a revised report of investigations — 4/76
(329 pp)

Environmental contamination from trace
elements in coal preparation wastes —
8/76 (69 pp)

Trace Elements in Coal:  occurrence and
distribution -- 6/77 (165 pp)
Trace element characterization of coal
wastes - first annual report -- 3/78
(58 pp)

Washability and analytical evaluation of
potential pollution from trace elements in
coal -- 3/78 (41 pp)
                                  641

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                        EPA/IERL-RTP REPORTS  (cont)
 Contractor
 (Contract No.)
 NTIS No.
 (EPA No.)
 Evaluation of Coal Cleaning Techniques
 Bituminous Coal
 Research
 (PH 86-67-139)
 U.S. Bureau of
 Mines
 U.S. Bureau of
 Mines
 Bituminous Coal
 Research
 (CPA 70-26)
 U.S.  Bureau of
 Mines

 U.S.  Bureau
 Mines

 Bituminous  Coal
 Research
 (68-02-0024)
J.J.  Davis
(68-02-1834)


Mitre
(68-02-1352)
 PB 193-486
 (APT1C 23423)
 PB 193-484/
 193-532
 (APTD 0579)

 RI 7440
 (APTIC 31443)
 RI 7518
 PB 205-185/
 199-484
 (APTD 0842)
 RI  7623


 TPR 51
 PB  210-821
 (APTD 1160)
PB 262-716/AS
EPA-600/2-76-
138

PB 232-011/AS
EPA-650/2-74-
030
Coal Reject Treatments
Bechtel
(PH 86-67-224)


A. D. Little
(PH 86-67-258)
PB 182-358
(APTD 1266)
PB 182-303
(APTD 1274)
 Report Title— Date PubllshedfNo. of Pages}
 An evaluation of coal cleaning processes
 and techniques for removing pyrltlc sulfur
 from fine coal (Interim report) — 9/69
 (285 pp)

 Same.  Final report — 2/70 (146 pp)
 Electrophoretlc - specific gravity
 separation of pyrlte from coal, laboratory
 study - 10/70 (15 pp)

 Hydrolyzed metal  Ions as pyrlte depressants
 1n coal  flotation:  a laboratory study —
 5/71  (26 pp)

 An evaluation of  coal  cleaning processes
 and techniques for removing pyrltlc sulfur
 from fine coal  — Final  report - 4/71
 (173 pp)

 Photoelectric concentrator for the wet
 concentrating table — 1972 (10 pp)

 Flotation of  pyrlte from coal  -- 2/72
 (9 PP)

 An evaluation of  coal  cleaning processes
 and techniques  for removing pyrltlc sulfur
 from  fine coal  (final  report)  -- 4/72
 (174  pp)

 Coal  preparation  environmental  engineering
 manual --  5/76  (729  pp)
An Interpretative compilation of EPA
studies related to coal quality and
cleanabmty -- 5/74 (276 pp)
Process costs and economics of pyrtte-
coal utilization (final report, Phases
142)-- 12/68 (187 pp)

A study of process costs and economics of
pyrlte-coal  utilization (final report) --
3/68 (265 pp)
                                   $42

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Contractor
(Contract No.)
  EPA/IERL-RTP REPORTS (cont)


                    Report Title -- Date Published(No.  of Pages)
NTIS No.
(EPA No.)
Coal Reject Treatments (cont)
Chemical Constr.
(CPA 22-69-151)
PB 203-958
(APTD 0768)

PB 203-959
(APTD 0769)
Coal Cleaning Prototype Plant

McNally Pittsburgh  PB 196-631
(PH 22-68-59)       (APTD 0606)
                    PB 196-632
                    (APTD 0607)

                    PB 196-633
                    (APTD 0608)

                    PB 196-634
                    (APTD 0609)
 Roberts/Schaefer
 (PH  22-68-62)
 Roberts/Schaefer
 (CPA 70-157)
 PB  220-700
 (APTD  0605)
 PB  220-701
 (APTD 0605)

 (Not  in NTIS)
 EPA-R2-73-154
 Chemical  Coal  Cleaning
 TRW
 (CPA 71-7)
 PB 204-863
 {APTD 0845)
                     PB 221-405
                     EPA-R2-73-173a
                     PB 221-406
                     EPA-R2-73-173B
                    High sulfur combustor study (Final report)
                    Vol. I, narrative summary — 2/71 (226 pp)

                    Same.  Vol. II, descriptive detail -- 2/71
                    (450 pp)
                    A study on design and cost analysis of a
                    prototype coal cleaning plant, Parts 1-6 --
                    7/69  (147 pp)

                    Coal  cleaning plant  prototype  plant
                    specifications,  Part 7 -- 7/69 (200 pp)

                    Coal  cleaning plant  prototype  plant
                    design drawings,  Part 8 - 7/69 (20 pp)

                    Design and cost  analysis of  a  prototype
                    coal  cleaning plant. Supplement -- 7/69
                    (13  pp)

                    Design and cost  analysis  study for a
                    prototype coal cleaning  plant, Vol.  I  —
                    8/69 (109 pp)

                    Same. Vol.  II -- 8/69  (211  pp)
                     Research program for the prototype coal
                     cleaning plant - 1/73 (133 pp)
                     Chemical removal of nitrogen and organic
                     sulfur from coal (final report) -- 5/71
                     (60 pp)

                     Chemical desulfurization of coal:  report
                     of bench scale developments.  Vol. I —
                     2/73 (184 pp)

                     Same.  Vol. II -- 2/73 (85 pp)
                                   643

-------
Contractor
(Contract No.)
  EPA/IERL-RTP REPORTS (cont.)


                    Report Title -- Date Published(No.  of Pages!
NTIS No.
(EPA No.)
Chemical Coal Cleaning (cont)
TRW
(68-02-0647)
Dow Chemical
(68-02-1329)

Exxon
(68-02-0629)
TRW
(68-02-1336)
TRW
(68-02-1335)
PB 232-083/AS
EPA-650/2-74-
025

PB 254-461/AS
EPA-650/2-74-
025a

PB 241-927/AS
EPA-650/2-75-032a

PB 246-311/AS
EPA-650/2-74-009k
PB 261-128/AS
EPA-600/2-76-143a
PB 261-129/AS
EPA-600/2-76-143b

PB 270-111/AS
EPA-600/2-77-
080
Applicability Studies

Mitre               PB 210-373
(F-192628-68C-0365) (APTD 0844)
                    PB 197-386
                    (APTD 0627)

                    PB 197-387
                    (APTD 0628)

Hittman Associates  PB 209-266
(EHSD 71-43)
Mitre
(USAF 723)

M. W. Kellogg
(68-02-1308)
(APTD 1079)
PB 211-505
EPA-R2-72-022

PB 239-496/AS
EPA-650/2-74-127
                    Applicability of the Meyers process for
                    chemical  desulfurizatlon of coal:   Initial
                    survey of fifteen coals -- 4/74 (200 pp)

                    Same:  survey of thirty-five coals -- 9/75
                    (212 pp)
                    Energy consumption:  the chemical  industry
                    (task 5) -- 4/75 (71  pp)

                    Evaluation of pollution control  in
                    fossil fuel conversion processes -- coal
                    treatment; section 1:  Meyers process --
                    9/75 (46 pp)

                    Meyers process development for chemical
                    desulfurization of coal, Vol. I  -- 5/76
                    (309 pp)

                    Same, Vol. II -- appendices -- 5/76 (124
                    PP)

                    Pilot plant design for chemical  desul-
                    furization of coal -- 4/77 (162 pp)
                    The physical desulfurization of coal --
                    major considerations for S09 emission
                    control - 11/70 (340 pp)  *

                    A survey of fuel and energy information
                    sources, Vol. I -- 11/70 (307 pp)

                    Same.  Vol. II - 11/70 (632 pp)
                    Electric power supply and demand forecasts
                    for the United States through 2050 -
                    2/72 (54 pp)

                    Survey of coal availabilities by sulfur
                    content -- 5/72 (168 pp)

                    Evaluation of sulfur dioxide emission
                    options for Iowa power boilers (task 3) --
                    12/74 (331 pp)

-------
Contractor
(Contract No.)
  EPA/IERL-RTP REPORTS (cont.)


                    Report Title -- Date Publ1shed(No.  of Pages)
NTIS No.
(EPA No.)
Applicability Studies (cont)
Battelle
(68-02-2112)
Battelle
(68-02-2163)
PB 256-020/AS
EPA-600/2-76/177a

PB 260-475/AS
EPA-600/2-76-177b

PB 277-408/AS
EPA-600/7-78-034
                    Fuel contaminants:  Vol. 1, Chemistry —
                    7/76 (177 pp)

                    Same; Vol. 2, removal technology evalu-
                    ation -- 9/76 (318 pp)

                    Physical coal cleaning for utility boiler
                    SO, emission control (task 851) -- 2/78
                    (1T2 pp)
                                     645

-------
                    ENVIRONMENTAL ASSESSMENT METHODOLOGIES
                   FOR FOSSIL ENERGY PROCESSES:  AN UPDATE
                           Robert P. Hangebrauck
                   Energy Assessment and Control Division
                  Industrial Environmental Research Laboratory
                   Office of Energy, Minerals and Industry
                      Office of Research and Development
                    U.S. Environmental Protection Agency
                Research Triangle Park, North Carolina  27711
                                  ABSTRACT
      Industrial Environmental Research Laboratory, Research Triangle Park,
 (IERL/RTP) is conducting a number of programs involving environmental assess-
 ment  and control technology for both energy and industrial processes.  This
 presentation focuses on some aspects of the environmental assessment (EA)
 methodology being developed and used as it relates to the Federal Interagency
 Environmental R&D program.

      A satisfactory environmental assessment methodology needs to address all
 program aspects such as air, water, solid waste, toxic substances, radiation,
 and noise.  Essentially all pollutants and environmental factors should be
 addressed including chemical substances; heat; noise; microorganisms; radiation;
 and air-, water-, and land-related physical factors.  Energy technologies
 selected for Investigation should be those with high commercial usage/applica-
 tion  potential.  The methodology must be practical and therefore has to be
 based on utilization of available or readily obtainable information.  Since
 absolute answers are not usually achievable, emphasis must be placed on compar-
 ative evaluations; e.g., definition of the relative best ways of controlling
 and relative comparison of waste streams and sources.

      The methodology is evolving out of necessity and should employ cost-
 effective approaches to effect broad-coverage screening initially followed by
 detailed screening to focus on areas of concern.  The approaches must be
 subject to continued refinement and improvement based on data and experience
 gained in doing EA studies.  Long lead times must be dealt with in development
 and implementation of the methodology.

      Several aspects of the developing environmental assessment methodology
are discussed Including the areas of current process technology background,
environmental data acquisition, current environmental background, environ-
mental objectives development, control technology assessment, and environ-
mental alternatives analysis.   Some of the barriers to Implementation are
noted also.

                                      646

-------
                              ACKNOWLEDGEMENTS
     The author acknowledges the direct Input and/or availability of Informa-
tion developed by IERL/RTP personnel and their contractors, and personnel  of
other laboratories In EPA1s Office of Research and Development.
                                     647

-------
                          ENVIRONMENTAL ASSESSMENT AND CONTROL TECHNOLOGY
                                       DEVELOPMENT PROGRAM
         ENVIRONMENTAL ASSESSMENT
CONTROL TECHNOLOGY DEVELOPMENT
00
                                         TECHNOLOGY AREAS

                                   CONVENTIONAL COMBUSTION
                                   NITROGEN OXIDE/COMBUSTION
                                   MODIFICATIONS
                                   FLUID BED COMBUSTION
                                   ADVANCED OIL PROCESSING
                                   COAL CLEANING
                                   SYNTHETIC FUELS

-------
                  CURRENT
                  PROCESS
                 TECHNOLOGY
                 BACKGROUND
                  ENVIRONMENTAL
                      DATA
                   ACQUISITION
                                                       CONTROL
                                                      TECHNOLOGY
                                                     DEVELOPMENT
                                                                                  IS
                                                                                BETTER
                                                                               CONTROL
                                                                               NEEDED?
                     CONTROL
                   TECHNOLOGY
                   ASSESSMENT
 REGULATORY
REQUIREMENTS
  CURRENT
  ENVIRON-
  MENTAL
BACKGROUND
ENVIRONMENTAL
  OBJECTIVES
 DEVELOPMENT
                                                                            ENVIRONMENTAL
                                                                             ALTERNATIVES
                                                                               ANALYSES
               TECH TRANSFER
                              cravinuNMtraiAL crauiraccrtiNu    i

                                FNVIRnMMFNTAI SRIFNTFft
                                                                                 I
                                          TECH TRANSFER
                                  ENVIRONMENTAL
                                     SCIENCES
                                       R&D
                                                                                 1
                                                               MEDIA
                                                                AND
                                                               HEALTH/
                                                                ECO
                                                               IMPACTS
                                                              ANALYSES
             ENVIRONMENTAL ASSESSMENT/CONTROL TECHNOLOGY DEVELOPMENT DIAGRAM

-------
                                      IERL/RTP STANDARDS DEVELOPMENT SUPPORT R&D
          IEHIENVIRONMENTAL
          ASSESSKEOTyCONTROL
              TECHNOLOGY
             DEVELOPMENT
Oi
o
  IERL DEVELOPS
   STANDARDS
SUPPORT PLAN (SSP)
    FOR EACH
TECIMOL06YAREA
                                                                                                      i
                                                                                               EPA PROGRAM OFFICE
                                                                                            PRIORITIZATION STUDIES FOR
                                                                                               STANDARDS SETTIHG
        IERL DEVELOPS:
• EWVIROKMEMTAL ASSESSMENT REPORT
• CONTROL GUIDANCE DOCUMENT
  DEVELOPED FOR EACH UNIQUELY
    DIFFERENT BASIC ENERGY
 TECHNOLOGY (AT THE COMMERCIAL
   OR DEMONSTRATION STAGE)   	
   EPA PROGRAM OFFICES
 DEVELOP PLAN FOR DETAILED
STANDARDS DEVELOPMENT FOR
     SPECIFIC ENERGY
   TECHNOLOGIES/SOURCES
   AND ORGANIZE SPECIFIC
   MEDIA WORKING GROUP
                                                                                              EPA PROGRAM OFFICES
                                                                                              CONDUCT ENGINEERING
                                                                                                STUDY TO DEVELOP
                                                                                             •ACK6ROUND DOCUMENT
                                                                                              EPA PROGRAM OFFICES
                                                                                           CONDUCT DETAILED INTERNAL
                                                                                             AND EXTERNAL REVIEWS,
                                                                                               PROPOSE IN FEDERAL
                                                                                               REGISTER, CONDUCT
                                                                                              FURTHER REVIEWS. AND
                                                                                             PROMULGATE STANDARD

-------
                    BREADTH OF  OBJECTIVES

•COMPREHENSIVE CONTROL GUIDANCE IS  NEEDED ON  REAL-TIME
  BASIS IN DEVELOPING,  EVALUATING,  AND DESIGNING  CONTROL
  TECHNOLOGY.

• ALL MEDIA/PROGRAM OFFICES NEED TO BE ADDRESSED  (AIR,
  WATER, SOLID WASTE, TOXIC SUBSTANCES, RADIATION,
  NOISE).
t
ALL IMPORTANT POLLUTANTS AND ENVIRONMENTAL FACTORS SHOULD
BE ADDRESSED (CHEMICAL SUBSTANCES; HEAT; NOISE; MICRO-
ORGANISMS; RADIATION; AND AIR-, WATER-, AND LAND-RELATED
PHYSICAL FACTORS).

TECHNOLOGIES INVESTIGATED SHOULD HAVE HIGH COMMERCIAL
USAGE/APPLICATION POTENTIAL-

SUMMARY OF NEEDS FOR ADDITIONAL DATA TO SUPPORT
STANDARDS DEVELOPMENT, ENFORCEMENT, HEALTH AND ECOLOGICAL
EFFECTS RESEARCH, AND CONTROL  TECHNOLOGY R&D.
                           651

-------
       EFFECT8 OF SCALE ON EA APPROACH AND OUTPUTS
Scale of Technol-
ogy Facility
 Practical Environ-
  mental Measurements
 Practical Uss of Information from
 Environmental Measurements
Bench-Scale
Facility
Effluent/Product
  Analyse*
 •   Identify Potential Pollutants
    for EA Measurements
Scatsabls Pilot or
 Demo Plant with
 Nonscsleable
 Control Tech-
 nology
Effluent/Product
  Analyses
                   Control Assays
 •  Good identification of
   Pollutants

 •  Projected Hazard of Untrested
   Streams Including Relation-
   ship to Fugitive Emissions
   and Spills

 •  Estimates of Ambient
   Loedings Using Estimstes of
   Add-On Control Effectiveness

 •  Basic  Data for Deaign
   of Controls
Full-Scale Facility
 with Applicable
 Controls
Effluent/Product
 Analyaes
                   Ambfent Measurements
                    and Field Surveys
•  Accurate Control Technol-
   ogy Evaluations

•  Good Projections of Ambient
   Loedings and Effects

•  Actuel Ambient Loedings and
   Effeeta
                                     652

-------
            ENVIRONMENTAL DATA ACQUISITION
                Level 1 Sampling and Analysis
EFFLUENT SAMPLES:
GASES
LIQUIDS
SOLIDS
EVALUATED FOR DISCHARGE TO MEDIA:
AIR
WATER
LAND
ANALYSES:
PHYSICAL
CHEMICAL
BIOLOGICAL
KEY ENVIRONMENTAL PARAMETERS:
HEALTH
ECOLOGICAL
  - FRESHWATER
  - MARINE
  -TERRESTRIAL
                               653

-------
           STATUS OF PHASED APPROACH TO
         CHEMICAL AND BIOLOGICAL ANALYSES
  LEVEL 1
     -  PROCEDURES  AVAILABLE
     -  ADDITIONS AND  REVISIONS UNDER STUDY
     -  EVALUATION  OF  LEVEL 1 CHEMICAL AND BIOLOGICAL
       PILOT  STUDIES  NEAR COMPLETION FOR FLUID BED
       COMBUSTION, GAS1FIER, AND TEXTILE PLANTS;
       RESULTS LOOK GOOD-
• LEVEL 2
     - GENERALIZED INTERIM PROCEDURES AVAILABLE  FOR
       ORGANICS
     - GENERALIZED PROCEDURES FOR INORGANICS WILL BE
       AVAILABLE SOON
     - BASIC OUTLINE FOR LEVEL 2 BIOASSAY PROTOCOL
       WILL BE AVAILABLE LATER THIS YEAR
  LEVEL 3
     - GUIDELINES ARE NOT YET DEVELOPED"* ILL BE SITE
       (PROCESS) SPECIFIC
                           654

-------
          ENVIRONMENTAL ASSESSMENT METHODOLOGY
                  - A PHASED APPROACH -
       PHASE I
   RAPID SCREENING
           POTENTIAL PROBLEM
PHASE II (CONFIRMATION)
  DIRECTED DETAILED
    SCREENING AND
  COMPLIANCE TESTS
         1
CONFIRMED PROBLEM
      PHASE III
      SELECTED
 POLLUTANT/EFFLUENT
   MONITORING AND
     EVALUATION
                               WASTE STREAMS.
                               RESIDUALS, AND
                                POLLUTANTS
                                 WHICH ARE
                               NOT PROBLEMS
            QUANTIFIED PROBLEMS
   WASTE STREAMS,
   RESIDUALS, AND
  POLLUTANTS WHICH
    ARE PROBLEMS
                           655

-------
                                  PARALLEL ANALYSIS APPROACH
                                           CHEMICAL
                                           ANALYSIS
                                                             DOES OR
                                                            COULD THE
                                                          SAMPLE CONTAIN
                                                         A CONCENTRATION
                                                          OF A SUBSTANCE
                                                         EXCEEDING A MEG
                                                             VALUE?
Ui
    SAMPLE
 SAMPLE
FRACTION
                                          BIOLOGICAL
                                           ANALYSIS
                                                              DOES
                                                           THE SAMPLE
                                                             GIVE A
                                                            POSITIVE
                                                       BIOLOGICAL RESPONSE
                                                          AND TO WHAT
                                                            DEGREE?

-------
             REGULATORY APPROACHES AND POTENTIAL REQUIREMENTS


 AIR (CAA)
        NSPS
        Guidelines/Documents
        PSD (BACT)
        Nonattalnment (LAER)
        NESHAP
        A1r Quality Criteria (Inputs on sources and  control technology documents)

 WATER (FWPCA, SOWA)
      * Effluent Guidelines
           - BPT (1977)
           - BAT (toxic  pollutants - 1984)
           - BCCT (conventional  pollutants -  1984)
           - BAT (all  other pollutants  •  1987)
      • NSPS
      ' Toxic and Pretreatment  Effluent Standards
      • Permits
           - Ocean Discharge
           • SDUA (underground  Injection  groundwater protection)
           - National  Pollution  Discharge Elimination System
           • Area-Wide Waste Treatment  Management (State/208 agencies)
      • Hazardous Materials (spills,  etc.)
      • Hater Quality  Standards  and  Criteria

 SOLID  WASTES (RCRA)
      ' Criteria,  Identification Methods, and Listing of Hazardous Wastes
     • Standards  Application to Owners and Operators of Hazardous Waste
        Treatment,  Storage  and Disposal Facilities
           - Media  Protection Strategies  (groundwater, surface water, air)
     • Guidelines

 TOXIC  SUBSTANCES  (TOSCA)
     * Implementation/Development
           -  Listing
           -  PMorltlzatlon
     * Reporting Requirements
     * Premature Notification
     • Testing
     • Control

RADIATION
     • Guidance for Control (CAA,  FWPCA.  RCRA,  TOSCA)

NOISE
     * Data Base, 1f Regulated 1n  Future
     * Guidance

LAND USE
     • Data Base, if Regulated In  Future
                                      657

-------
         CURRENT ENVIRONMENTAL
               BACKGROUND

• Summary of Key Federal Regulations

• Noncriteria Ambient Baseline Data
• Environmental Siting Scale
  Models for Technologies

-------
           ENVIRONMENTAL OBJECTIVES  DEVELOPMENT

          MULTIMEDIA ENVIRONMENTAL GOALS  (NEGs)
             PROVIDE ASSESSMENT  ALTERNATIVES

• MINIMUM ACUTE TOXICITY EFFLUENT (MATE)
• EXISTING AMBIENT STANDARDS (ES)
• ESTIMATED PERMISSIBLE CONCENTRATIONS (EPC)
• NATURAL BACKGROUND/ELIMINATION OF  DISCHARGE  (NB)
' BEST TECHNOLOGY (BT)
                           659

-------
                                ENVIRONMENTAL OBJECTIVES DEVELOPMENT
                                      . >'~ '
                  -••.•*••
               CHEMICAL
 -2.  BASEDON
#*'. AMBIENT n
                                         COMPLEX-EFFLUENT
                                            BIOLOGICAL
                                             RESPONSE
                                              LEVELS
                                        (BIOASSAY CRITERIA)
                                BASED ON
                              TECHNOLOGY*
 MOST ACTIVE AREAS ARE SHADED.
•INCLUDES EXISTING STANDARDS
PHYSICAL"
FACTORS
                                                                 (HEAT; NOISE; MICRO-
                                                                 ORGANISMS; RADIO-
                                                                 NUCLIDES; NONIONIZING
                                                                 RADIATION; WATER- OR
                                                                 LAND-RELATED PHYSI-
                                                                 CAL FACTORS)

-------
               EXAMPLE: SUMMARY OF AIR-HEALTH MATE VALUES
MEG* CATEGORY
MATE VALUES, »g/m3



    100      103
10*
ID*
15. BENZENE; SUBSTITUTED
BENZENE HYDROCARBONS
A. Dwuene; Mumnuuuiuino
DtSUDStltUtM, rtHySUUSinuTBO
16. HALOGENATED AROMATICS
A. Ring Substitutad
B. llaMeiMteJ Afcyl Skfc Chain
17. AROMATIC NITRO COMPOUNDS
A. Simple
B. With AdditionM i muJWitti
Groups
1& PHENOLS
A mm 	 a 	 •— a^-^
A. ivionoiiyuiiu
B. Diiydrics; rwynvdrics
C. Fined Rinf Hydroxy Compounds









••••••••





1HMM







—

-------
          APPLICATION OF MEG'S CATEGORIES:

FOR CHEMICAL COMPOUND IDENTIFIED BUT NOT INCLUDED IN
MEG'S LIST OR WITHOUT ESTABLISHED MEG VALUES:

   1.  DETERMINE CATEGORY-

   2-  DETERMINE SUBCATEGORY.

   3-  FROM MEG'S SUMMARIES, FIND LOWEST MEG
       VALUE FOR COMPOUNDS IN THE SUBCATEGORY.

   4-  ASSUME THAT MEG VALUE WILL BE NO LOWER
       THAN THE MOST STRINGENT VALUE INDICATED
       FOR COMPOUNDS IN THE SUBCATEGORY.

   5-  SEND RTI A POSTCARD CONCERNING THE
       COMPOUNDS SO THAT  IT MAY BE  INCLUDED  IN
       A CANDIDATE LIST FOR FUTURE  MEG'S CON-
       SIDERATION.
                           662

-------
        EXAMPLE OF NUMBERING
         SYSTEM FOR ORGANIC
              COMPOUNDS
CATEGORY
18
18 A-
	PHENOLS
	MONOHYDRICS
     18A020    PHENOL
     18A040    CRESOLS
     18A060    2-METHOXYPHENOL
     18A080    ETHYLPHENOLS
     18A100    PHENYLPHENOLS
     18A120    2,2'-DIHYDROXYDIPHENYL
     18A140    XYLENOLS
                    663

-------
                MULTIMEDIA ENVIRONMENTAL GOALS

• VOLUM.ES 1 & 2 AVAILABLE NOVEMBER 1977 (EPA-600/7-77-136A,  B)
  - INITIAL METHODOLOGY ESTABLISHED
  - MASTER LIST OF 650 POLLUTANTS PRESENTED
  - 216 CHEMICALS ADDRESSED

* VOLUMES 1A, 3, 4 TO BE AVAILABLE EARLY 1979
  - MINOR REVISIONS IN METHODOLOGY INTRODUCED
  - MEGs POLLUTANT IDENTIFICATION NUMBERS ASSIGNED
  - > 500 ORGANIC COMPOUNDS ADDRESSED

• EXPANDED INORGANICS MEGs AVAILABLE IN 1979
  - COMPUTER-GENERATED
                          664

-------
            CONTROL TECHNOLOGY
                ASSESSMENT

* GAS TREATMENT

• LIQUIDS TREATMENT

0 SOLIDS TREATMENT

• FINAL DISPOSAL

* PROCESS MODIFICATION

• COMBUSTION MODIFICATIONS

' FUEL CLEANING.

' FUGITIVE EMISSIONS CONTROL

' ACCIDENTAL RELEASE TECHNOLOGY
                 665

-------
           CONTROL TECHNOLOGY ASSESSMENT

* CONTROL ASSAY DEVELOPMENT

     - FOR USE WITH LEVEL 1
     - PROCEDURES FOR WATER EFFLUENTS ARE DEFINED
       AND WILL REQUIRE FURTHER DEVELOPMENT AND
       EVALUATION THROUGH APPLICATION
     - CONCEPT FOR GASEOUS EMISSIONS DEFINED
     - NO WORK YET ON SOLID WASTE/LAND DISPOSAL
       ASPECTS


f MULTIMEDIA ENVIRONMENTAL CONTROL ENGINEERING HANDBOOK
     - FIRST DRAFT BEING REVIEWED INCLUDES EXTENSIVE
       ORGANIZED CONTROL DEVICE LISTINGS
     - INITIALLY WILL CONTAIN ONLY ABOUT 100 SPECIFIC
       DEVICE DATA SHEETS
                           666

-------
          CONTROL ASSAY DEVELOPMENT TEST SEQUENCE
                     FOR WASTEWATER
 SOURCE A
   1
SOURCE B
BYPRODUCT
 REMOVAL
               i
                                    FOR
                                 LEVEL 1
                                  ASSAY
         COMPOSITE SAMPLE

        SOLIDS SEPARATION

                                    CARBON ADSORPTION
          BIO-OXIDATION
                         ___        ^^^^ M
                              _-»-_^^^ ^
                                       ION EXCHANGE
        CARBON ADSORPTION
          ION EXCHANGE

                             667

-------
     ENVIRONMENTAL ASSESSMENT
            DATA SYSTEMS

Fine Particle Emissions Information
System (FPEIS)
 — Operational
                   ».
Gaseous Emissions
Data System
Liquid Effluents
Data System
Solid Discharges
Data System
Under Development
                     668

-------
                                    SCOPE OF SOURCE ANALYSIS MODELS
             SAM/IA
        (RAPID SCREENING)
        NO TRANSPORT/
       TRANSFORMATION
       •MEG*: MATE ONLY
NO
                                                          EFFLUENT
                                                           STREAM
                                                        CONCENTRATION
      SAM/I
   (SCREENING)
CRUDE TRANSPORT/
TRANSFORMATION
ANALYSIS
MEGs: ADD OTHER
ASSESSMENT
ALTERNATIVES
         SAM/11
(REGIONAL SITE EVALUATION)
  AMBIENT POLLUTANT
  CONCENTRATION
  - SITE-SPECIFIC
    TRANSPORT/
    TRANSFORMATION
  - CROSS-MEDIA IMPACTS
  MEGs: ALL ALTERNATIVES
  POPULATION EXPOSURE
  OTHER SITE-SPECIFIC
  FACTORS
                          I
                                                                 f
                                                          SAM OUTPUT
                                                    LEVEL 2 OR 3 SAMPLING NEEDS
                                                    DEGREE OF HAZARD
                                                    TOXIC UNIT DISCHARGE RATE
                                                    IMPACT FACTORS

-------
          SOURCE ANALYSIS MODEL
            DEVELOPMENT STATUS
* SAM IA:  RAPID SCREENING
    - REPORT IN WORKBOOK FORMAT AVAILABLE  (EPA-600/7-78-015)
    - WORK STARTED TO INCORPORATE BIOASSAY
      RESULTS (WILL BE CALLED SAM IB)

• SAM It   INTERMEDIATE SCREENING
    - DRAFT REPORT IN WORKBOOK FORMAT
      BEING REVIEWED

• SAM Hi  REGIONAL SITE EVALUATION
    - NO  WORK DONE ON THIS YET
    - SOURCE ASSESSMENT MODEL AVAILABLE
                     670

-------
   APPROACH FOR APPLICATION OF SAM'S TO PHASED CHEMICAL ANALYSIS
LeveM
Sampling &
Analyst

Level 1 Results
•*

SAMIA

, I
SAMI
                       1
                 • Recommended Level 2 Analyses
                 • Potential Problem Discharges
             Level 2
           Sampling A
            Analysis
Level 2 Results
  I
                          SAMIA
 • Screened Pollutants
 • Screened Problem Discharges
  I
            SAMI
        I
                                Levels
                               Sampling
                                Analysis
J • Recommended Level 3 Analyses
  • Confirmed Problem Discharges

      Levels   r
                    Results
                                 SAM II
'Optional
                                    • Quantified Problem
                                      Pollutants
                                    • Quantified Problem

-------
                                   SAM I POLLUTANT DISCHARGE OVERVIEW
           .Discharge
Waste Stream
-Gas, Liquid, SoRd)
                Control
                 Device
                O  On
                D  ON
                               Residual
                                       I
                                Liquid
                               Residual
                                       I
                                Solid
                               Residual
a) S. water Surface water,
b) A: Air, W: Water, L: Land
e) H: Health, E: Ecological
                                       I
                                       I
                                 Ground water
Deceiving
Medium
XAir
r


~Wrter
^^

"^tand-
. Final ,
L, 	 Receiving 	 J Receptor 1
I BodX Medium 1
i
I
I
1
I_
1^^
-r*
I
J — — """'
Mr * |
River S. water
Lake a water
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-------
             OUTPUT OBJECTIVES FOR
            ENVIRONMENTAL ASSESSMENT

- DEFINED RESEARCH DATA BASE FOR  STANDARDS

• QUANTIFIED CONTROL R&D NEEDS

• QUANTIFIED CONTROL ALTERNATIVES

' QUANTIFIED MEDIA DEGRADATION ALTERNATIVES

• QUANTIFIED NONPOLLUTANT EFFECTS AND  SITING
  CRITERIA ALTERNATIVES
                    673

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    KEY E.A--RELATED REPORTS

* STANDARDS SUPPORT PLAN
' POLLUTION CONTROL GUIDANCE DOCUMENT
• SOURCE TEST AND EVALUATION REPORT
• ENVIRONMENTAL ASSESSMENT REPORT
                674

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     STANDARDS SUPPORT PLAN (SSP)
INTRODUCTION
DEFINITION OF TECHNOLOGIES
THE STANDARDS SUPPORT SCHEDULE
DISCUSSION OF THE STANDARDS SUPPORT SCHEDULE
   - PROJECTED DEVELOPMENT OF TECHNOLOGIES
   - REQUIREMENTS OF THE EPA ACTS
   - EPA PLANS FOR REGULATORY ACTIVITIES
   - EPA RESEARCH AND DEVELOPMENT ACTIVITIES
   - PROGRAM OFFICE VIEWS OF R&D DATA NEEDS
                    675

-------
POLLUTION CONTROL GUIDANCE DOCUMENT (CGD)
• POLLUTANTS AND PROCESS SOURCES

• ENVIRONMENTAL EFFECTS OF KNOWN POLLUTANTS

• POLLUTION CONTROL TECHNOLOGY

' POLLUTANT DISCHARGE LIMITS

• FUTURE DEVELOPMENT OF EFFLUENT AND EMISSION
  STANDARDS

• EFFLUENT AND EMISSION MONITORING
                     676

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               ENVIRONMENTAL ASSESSMENT
     SOURCE TEST AND EVALUATION  REPORT   (LEVEL 1)
          PRESSURIZED FBC  MINI PLANT  (EXAMPLE)
• SUMMARY
• PLANT DESCRIPTION
- SAMPLING METHODOLOGY
f ANALYTICAL PROCEDURES
• TEST RESULTS
• CONCLUSIONS AND RECOMMENDATIONS
                     677

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       ENVIRONMENTAL ASSESSMENT REPORT (EAR)
• PROCESS DESCRIPTION OF THE SYSTEMS MAKING UP THE
  TECHNOLOGY

• CHARACTERIZATION OF INPUT MATERIALS,  PRODUCTS,  AND
  WASTE STREAMS

• PERFORMANCE AND COST OF CONTROL ALTERNATIVES

* ANALYSIS OF REGULATORY REQUIREMENTS AND ENVIRONMENTAL
  IMPACTS BY MEDIA WITH REGIONAL CONSIDERATIONS

• SUMMARY OF THE NEEDS FOR ADDITIONAL DATA TO SUPPORT
  STANDARDS DEVELOPMENT, ENFORCEMENT, HEALTH AND
  ECOLOGICAL EFFECTS RESEARCH, AND CONTROL TECHNOLOGY
  R&D
                           678

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               BARRIERS TO
      EA METHODOLOGY IMPLEMENTATION

• COMPLEXITY OF POTENTIAL PROBLEMS

* DIFFICULTIES IN CROSSING DISCIPLINARY AND
  ORGANIZATION LINES

* BRIDGING THE GAP BETWEEN THE SCIENCES AND
  ENGINEERING

• DIFFICULTIES IN CHANGING FROM SET PATTERNS AND
  TRADITIONAL APPROACHES

' RELUCTANCE TO USE AVAILABLE EFFECTS DATA

* LACK OF REALIZATION OF THE IMPORTANCE OF COMMON
  BASES TO PROMOTE COMMUNICATION AND EVOLUTIONARY
  IMPROVEMENT OF METHODOLOGIES

* AREAS NEEDING FURTHER RESEARCH
                      679

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            EMPHASIS ON PRACTICAL GOALS

* ENVIRONMENTAL ASSESSMENT (EA) STUDIES NEED TO
  DO SOMETHING MORE THAN EMPHASIZE TRADITIONAL
  PROBLEMS THAT HAVE BEEN THE SUBJECT OF YEARS
  OF INVESTIGATION.

• APPROACH MUST BE DESIGNED TO UTILIZE AVAILABLE
  OR READILY OBTAINABLE INFORMATION; I.E.,
  APPROACHES MUST BE PRACTICAL-

• ABSOLUTE ANSWERS NOT POSSIBLE;  THEREFORE,
  RELATIVE OR  COMPARATIVE  ANSWERS DEFINING THE
  RELATIVE BEST WAYS OF CONTROLLING  OR RELATIVE
  COMPARISONS  OF WASTE STREAMS AND SOURCES
  ARE NECESSARY.

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                   STATE OF KNOWLEDGE/GAPS

• AN EA METHODOLOGY IS EVOLVING OUT OF NECESSITY.

f NEED TO EMPLOY COST-EFFECTIVE APPROACHES TO EFFECT
  BROAD-COVERAGE SCREENING INITIALLY AND DETAILED
  SCREENING SUBSEQUENTLY TO FOCUS ON AREAS OF CONCERN-

• APPROACHES MUST BE SUBJECT TO CONTINUED REFINEMENT
  AND IMPROVEMENT BASED ON EXPERIENCE IN PERFORMING
  EA STUDIES.

* LONG LEAD TIMES MUST BE DEALT WITH IN DEVELOPING AND
  IMPLEMENTING METHODOLOGY.

• METHODOLOGY MUST TAKE INTO ACCOUNT PRESENT EA PROGRAM
  OFFICE AREAS OF CONCERN; E.G., POLLUTANT LISTS,  STANDARDS-
                          681

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                          ULTIMATE ANSWERS

• ACCEPT THAT THE ONE-POLLUTANT-AT-A-TIME APPROACH TAKES DECADES
  OF TIME TO BUILD POSSIBLE PROOF OF CHRONIC EFFECTS FOR AN
  EXTREMELY LIMITED SET OF POLLUTANTS AND THEREFORE HAS SEVERE
  LIMITATIONS FOR CONTROL DEVELOPMENT GUIDANCE-

• PROVIDE REAL-TIME GUIDANCE AND FILL IN EFFECTS-DATA GAPS FOR
  CONTROL TECHNOLOGY DEVELOPMENT, EVALUATION, AND DESIGN BY
  EMPHASIZING USE OF SHORT-TERM EXPOSURE TOXICITY DATA IN
  EVALUATING EFFLUENTS DIRECTLY-

  POSSIBLE TOXICITY DATA SOURCES ARE:
    - COMPLEX EFFLUENT BIOASSAYS,
    - SIMILAR DATA AVAILABLE IN THE LITERATURE,
    - EXPERIMENTS FOR SPECIFIC CHEMICAL SUBSTANCES
      OR CLASSES OF SUBSTANCES.

• TAKE BEST ADVANTAGE OF EXISTING EA METHODOLOGY BY MAXIMIZING
  COMMUNICATION OF PROCEDURES, REFINEMENT IN PROCEDURES, AND
  RESULTS OF INDIVIDUAL STUDIES-

• MAXIMIZE SUPPORT FROM THE ENVIRONMENTAL SCIENCES LABS IN
  DEVELOPING EA METHODOLOGY.

• INTEGRATE KEY EPA PROGRAM OFFICE ASPECTS AND METHODOLOGIES-

• DEVOTE RESOURCES TO DEVELOPMENT, STANDARDIZATION, AND
  COORDINATION OF EA METHODOLOGY.
                                682

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                     REVIEW OF  REGULATIONS AND  STANDARDS
                          INFLUENCING  COAL CLEANING

             P.  Van Voris1,  R.  A.  Ewing , and J. W. Harrison
                       Battelle's  Columbus Laboratories
                               Columbus, Ohio
                        o
                         Research  Triangle Institute
                    Research Triangle  Park,  North  Carolina


                                  ABSTRACT


     With the growing public concern over health and  ecological effects  of
man-generated wastes has come increased legislation which places strict  regu-
lations and standards for the release of potentially  hazardous materials.
Although some of this environmental legislation may not be directed specifically
toward the coal cleaning industry itself,  the Federal acts nevertheless
encompass and embrace the industry completely.   Thus, these regulations  and
standards that have been adopted by the United States, as well as Canada,
France, Norway, and Sweden, have required the industry to invest a great deal
of time and money in the development and installation of pollution control
devices or technologies for the proper disposal of wastes.

     In this review the following Federal acts, which constitute the primary
regulatory authority governing pollution from activities associated with coal
cleaning processes, are examined.

     Air Pollution
       Clean Air Act of 1970                (P.L. 91-604)
       Energy Supply and Environmental
         Coordination Act of 1974           (P.L. 93-319)
       Clean Air Act Amendments of  1977     (P.L. 95-95)

     Water Pollution
       Federal Water Pollution Control
         Act Amendments of  1972             (P.L. 92-500)
       Clean Water  Act of  1977             (P.L. 95-217)

     Solid Waste
       Solid Waste  Disposal Act of  1965     (P.L.  89-272)
       Resource Recovery  Act of 1970        (P.L.  91-512)
       Resource Conservation and
         Recovery  Act  of  1976               (P.L.  94-580)
                                       683

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     All of the above acts are administered and enforced by the U.S. Environ-
 mental Protection Agency and are embodied in Title 40 of the Code of Federal
 Regulations.

     The applicability of the provisions of these acts to the coal cleaning
 Industry, as well as some specific state regulations, are examined.  This,
 along with a critique of Federal acts which at this time only have potential
 applicability, constitute the body of this report.
                            INTRODUCTION

      During the past half  century, increased  industrialization,

product demand, additional leisure time, and  population growth

have  given rise to an  increased use of energy.   Both the U.S. En-

vironmental Protection Agency and the Department of Energy have

developed a series of  energy scenarios showing  that energy needs

may grow from our current  annual consumption  of approximately 75
                        15
Quads (1 Quad « 1 x 10   Btu)  of energy to a  conservative esti-

mate  of nearly 110 Quads by the year 2000.  Coal is currently

supplying 24 percent of the total Quads and is  predicted to sup-

ply 33  percent by the  turn  of  the century.  The overall projected

increase in United States energy usage is approximately 46 per-

cent, in relation to only a 21 percent expected increase in the

U.S.  population size (U.S.  Department of Commerce,  1977).  Other,

more  pessimistic projections  (Ehrlich et al., 1973;  Hardin, 1973;

and Garvey,  1972)  have painted even more startling  scenarios

showing  energy consumption  doubling in the next quarter century.
                                684

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     With this increased demand for energy came man's understand-
ing that the earth is a finite structure that must support a
broad diversity of life for an infinite amount of time.  This re-
alization, along with the recognition of the environmental blight
that man had previously caused, gave birth to environemtnal con-
cerns which, in turn, spawned governmental regulations and their
subsequent promulgation designed to help ensure the preservation
of the ecosystems and their inhabitants.
     Because of the projected increase in our reliance on coal as
one of the primary energy sources for our country, as well as the
potential role of coal cleaning in reducing environmental risks
associated with coal, it was felt that a review of the major fed-
eral regulations affecting the coal preparation industry was
necessary.  This review is divided into the key areas of regula-
tory control—air, water  and  solids—and each is examined both
at the federal and state levels.

               REGULATIONS AFFECTING COAL CLEANING
     In order to evaluate the existing and pending environmental
regulations that will affect coal cleaning, several reviews of
Federal and State regulations governing pollution resulting from
activities associated with coal cleaning, transportation, stor-
age,  and handling have been prepared (Ewing et al., 1977; Cle-
land and Kingsbury, 1977;  Energy and Environmental Analysis, Inc.,
1976;  Harrison, 1978; and Ewing et al., 1978).  The scope of
these reviews included the regulations influencing the combustion
                               685

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of coal  as a fuel  but excluded  those for the conversion  of coal

to coke  or to liquid or  gaseous fuels.   The results of the most

recent review (Ewing et  al., 1978)  are  the basis  for this paper

and,  unfortunately,  will  be outdated by the time  this has been

published.   Therefore, repeated updates of this report are planned

as a  portion of the  U.S.  EPA Technological and Environmental

Assessment  of Coal Cleaning Processes program.

      The following Federal  acts  constitute the primary regulatory

authority governing  pollution resulting  from activities associ-

ated  with coal cleaning processes.


                   Primary Regulatory  Authority
                   Governing  Pollution Resulting
                   From Coal  Cleaning  Processes
            Air Pollution

                Clean Air Act of 1970               (P.L. 91-604)
                Energy Supply and Environmental       (P.L. 93-319)
                  Coordination Act of 1974
                Clean Air Act Amendments             (P.L. 95-95)
                  of 1977

            Water Pollution

                Federal Water Pollution Control       (P.L. 92-500)
                  Act Amendments of 1972
               Clean Water Act  of 1977              (p.L. 95-217)
            Solid Waste

               Solid Waste Disposal Act             (P.L. 89-272)
                 of  1965
               Resource Recovery Act of 1970         (P.L. 91-512)
               Resource Conservation and             (P.L. 94-580)
                 Recovery Act of 1976
               U.S.  Geological Survey -             Title 30 CFR,
                 Department of Interior               Part 211
           Potentially applicable for Chemical Coal Cleaning - Toxic
             Substances Control Act of 1976 (P.L. 94-469).
                                  686

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     These acts are embodied in Title 40 of the Code of Federal
Regulations and their applicability to coal cleaning is discussed
in the following sections.
     State regulations are generally written or amended to incor-
porate, as a minimum, the provisions of the Federal laws..  In
some instances, state regulations are more stringent than Federal
regulations.  The states are usually required to submit implemen-
tation plans for U.S. EPA approval outlining how Federal standards
will be met and specifying a reasonable time frame for implement-
ing those standards.  This state certification procedure is es-
sentially complete for air pollution, well underway for water pol-
lution, and just beginning for solid wastes.
                    Air Pollution Regulations
Federal
     The development and  implementation of air pollution controls
have been approached in two different ways by the U.S. Environ-
mental Protection Agency  in accordance with the provisions of the
Clean Air Act  of 1970.  Source emission standards are  designed to
regulate the quantities of pollutants emitted from point  sources,
whereas ambient air  quality standards are designed to  regulate
the concentrations of pollutants  in the .atmosphere.
     Ambient Air Quality  Standards.   The  U.S. EPA, under  Section
109 of the  Clean Air Act  of 1970,  has established national pri-
mary  and  secondary ambient  air quality  standards  (NAAQS)  that
regulate  pollutant  levels in  order to protect,  respectively,  human
                                687

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health and public welfare  (property and plant and animal life)
(U.S. Environmental Protection Agency, 1977a).
     Implementation is the responsibility of the individual
states, under a State Implementation Plan  (SIP), which must be
approved by the U.S. EPA.  Also, the permissible levels for cer-
tain named pollutants (criteria pollutants), which the SIP must
provide Will not be exceeded, are established by the U.S. EPA.
Some of these "criteria pollutants" arise mainly from motor ve-
hicles; however, pollutants such as total suspended particulates,
sulfur oxides, and nitrogen oxides, arise from stationary sources
and are released mainly through coal combustion.  Current national
ambient air quality standards for the criteria pollutants are
summarized in Table 1 (U.S. Environmental Protection Agency,
1977a).
        Table 1.  National ambient air quality standards

PartlcuTates


Sulfur dioxide




Averaging Period
Annual geometric mean
Max. 24-hr concentration, not to
be exceeded more than once
per year
Annual arithmetic mean
Max. 24-hr concentration, not to
be exceeded more than once
per year
Max. 3-hr concentration, not to
be exceeded more than once
oar vaar
Primary
75 Mg/m
260 Mg/m3

80MQ/m3
(0.03 ppm)
365 pg/nr
(0.14 ppm)

«

Secondary
60 /^g/m3
150 Mg/m3

60 /ug/m3
(O.Oz ppm)
260 /ug/m3
(0.1 ppm)

1300 Mg/m3
(0.5 ppm)

                               688

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                        Table 1.   (Continued)

Carbon monoxide
Hydrocarbons
Averaging Period
Wax. TT-1W5 IjoTfESfitFitTbn, not to
be exceeded more than once
per year
Max. 1-hr, concentration, not to
be exceeded more than once
per year
Max. 3-hr (6-9 A.M.) concentra-
tion, not to be exceeded more
than once a year
Primary
10 mg/m3
(9 ppm}
40 mg/3
(35 ppm)
160 Mg/m
(0.24 ppm)
Secondary
10 mg/m3
Oppm)
40 mg/m3
(35 ppm)
160 Mg/m
(0.24 ppm)
     Photochemical oxldants.  Annual arithmetic mean
                       Max. 4-hr concentration
                       Max. 1-hr concentration, not to    160 Mg/m3   160 Mg/m3
                       be exceeded more than once       (0.08 ppm)   (0.08 ppm)
                       per year
     Mltrooen dioxide  .     Annual arithmetic means         100 Mg/m3   100 Mg/m3
                                                (0.05 ppm)   (0.05 ppm)
     New Source Performance Standards.   In accordance with Section
111 of  the 1970 Clean  Air Act, the  U.S. EPA is  required  (1) to
compile a list of categories of emission sources  that may con-
tribute significantly  to air pollution and  (2)  to establish Fede-
ral standards of performance for new and modified stationary
sources in such categories.  Unlike the ambient air quality stand-
ards, these standards  of performance are not based on the effects
of pollutants on public health and  welfare but  on "the degree of
emission limitation  achievable through the application of the best
system  of emission reduction which  (taking into account  the cost
of achieving such reduction) the Administrator  determines has been
                                 689

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 adequately demonstrated".*   Agency terminology for this  is  BACT

 (Best Available  Control  Technology).

     Standards have  now  been promulgated  for  over  25  types  of

 sources.  The foremost category on the  list is fossil-fuel-fired

 stationary sources;  many provision of the Clean Air Act  Amend-

 ments of  1977 are aimed  specifically at such  sources,  and the re-

 strictions applied are much  more rigorous than in  the  past.  Where

 the original New Source  Performance Standard  (NSPS) for  large

 [>250 million Btu/hr (73 MW)] coal-fired  boilers permitted  the

 emission  of 1.2  Ib SO2/million  Btu, the amended Act specifies, in

 addition, that the revised NSPS "...shall reflect  the  degree of

 emission  limitation  and  the  percentage  reduction achievable

 through application  of the best technological  system of  continu-

 ous emission reduction ...",  i.e., a percentage reduction will be

 required  rather  than maintenance of emissions  below an upper

 limit.  A comparison of  the  newly-released revised NSPS  and ex-

 isting NSPS is presented in  Table 2.  The criteria are tempered

 by the usual energy, cost, and  environematnal  impact considera-

 tions.  Also, credit may be  taken for any cleaning of  the fuel or

 reduction in the pollution characteristics of  the  fuel after ex-

 traction  (i.e., mining)  and  before combustion.

     Since NSPS's for fossil-fuel-fired boilers apply  only to

units above 250 million  Btu/hr  (73 MW), very few boilers employed
*However, it should be noted that the setting of NAAQS provides
 the justification for setting emissions standards for these pol-
 lutants.
                               690

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               Table 2.  Comparisons of existing  NSPS
                         and  revised NSPS
                        Existing NSPS           Revised NSPS*
           S02         1.2 Ib/million Btu     0.2 Ib/million Btu**
                                            85% reduction
       Participates    0.1 Ib/million Btu     0.03 Ib/million Btu
                                            99% reduction from
                                            uncontrolled sources
           N0x         0.7 Ib/million Btu     0.6 Ib/million Btu
                                            65% reduction from
                                            uncontrolled sources
       Currently no NSPS for Industrial Boilers
        *U.S.  Environmental Protection Agency, 1978a.
        **Limits for no more than 1.2 lb/106 Btu with 0.2 lb/106 as
         the floor.
in coal cleaning activities  (thermal dryers)  will be affected by
these new  standards.  On the other hand,  many,  if not most, of
the potential utility users of coal employ boilers of this size
or larger.   Thus, depending somewhat on  the  S02 regulations final-
ly promulgated,  the revisions  to the NSPS for fossil-fuel-fired
boilers will have a significant, but direct,  impact upon coal
cleaning.   The role of coal cleaning in  the  utilization of coal
undoubtedly will be influenced materially, although 'the way in
which this will  be manifested  is as yet  unclear.  The percentage
reductions required are unlikely to be  achieved by coal cleaning
alone,  so  some supplemental  form of S02  removal will probably be
required..   On the other hand,  the converse may also be true,
                                 691

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especially on high sulfur coal, so coal cleaning may be technical-
ly desirable (and probably also economically and environmentally
advantageous) to supplement flue gas desulfurization.
     New source performance standards that are directly applica-
ble to coal cleaning processes are those for new and modified
coal preparation plants and handling facilities which include:
thermal dryers, pneumatic coal cleaning equipment  (air tables),
coal processing and conveying equipment (including breakers and
crushers), coal storage systems (except for open coal storage
piles), and coal transfer and loading systems (including barge
loading facilities).  Although the regulations in 40 CPR Part 60
(U.S. Environmental Protection Agency, 1977b) do not specify
their application elsewhere, the explanatory discussion in the
promulgation announcement (41 FR 2232, January 15, 1976) also in-
cluded other sources that handle large amounts of coal, such as
power plants, coke ovens, etc.
     These NSPS, which are applicable to all coal preparation or
handling facilities processing more than 200 tons/day, include
(U.S. Environmental Protection Agency, 1977b)i
     •  emissions from thermal dryers—may not exceed  0.070
        gr/dscm (0.031 gr/dscf)  and 20 percent opacity
     •  emissions from pneumatic coal cleaning equipment—
        may not exceed 0.040 gr/dscm (0.018 gr/dscf)  and 10
        percent opacity
     •  emissions from any coal processing and conveying
        equipment,  coal storage system, or coal trarisfer
                               692

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        and loading system processing coal (nonbituminous as
        well as bituminous) — may  not exceed  20 percent  opacity.
     Hazardous Pollutant Emission Standards.   The atmospheric
emission of several hazardous pollutants is already regulated un-
der Section 112 of the Clean Air Act of 1970.  Two of these (be-
ryllium and mercury) are found in coal but not at levels such
that their emission is expected to violate standards.  The estab-
lishment of regulations governing arsenic, polycyclic organic
matter (POM), and cadmium emissions is now under consideration.  A
national ambient air quality standard for lead has just been pro-
posed (U.S. Environmental Protection Agency,  1977c).  Except for
POM's, emissions of the other hazardous pollutants mentioned
above (in concentrations likely to be governed by the standards)
are expected to be emitted only from sources such as those found
in the nonferrous metal industry or from the combustion of leaded
gasoline and the standards should have little effect upon coal
cleaning processes.
     Prevention of Significant Deterioration of Air Quality.  A
new Part C  (Sections 160-169) was incorporated into the Clean Air
Act Amendments of 1977 for the prevention of significant deteri-
orations (PSD) of the present ambient air quality.  Three land-
use classes are established which are interpreted by the U.S. EPA
to have the following types of development:
     •  Class I - little or no development
     •  Class II - scattered development
     •  Class III - concentrated or  large-scale development.
                                693

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 Classification in Class I is mandatory for national parks exceed-
 ing 6,000 acres in size and wilderness areas.  The verbiage is
 complex and involved,  but the significant fact, with respect to
 coal cleaning processes, is that any new source in an area sub-
 ject to the provisions of this section is to employ the Best
 Available Control Technology for each pollutant subject to regu-
 lation.   Cost considerations for achieving such emission reduc-
 tion is  not invoked  as a factor.   Thus,  the best available con-
 trol technology required for PSD must be better than those of  the
 NSPS.   It is obvious that these  are  site-specific problems and
 that a uniform national  standard  will not be utilized.   Each pro-
 posed new source  will  be considered  by the"affected state  on a
 case-by-case basis under the state implementation plan.  The Act
 provides  for maximum allowable increases  in  S02  and particulates
 for  each  land-use class, with the provision  that  the NAAQS will
not  be exceeded.  Allowable  pollutant  increases are shown  for  all
three land-use classes in Table 3, along with national primary
and  secondary ambient air quality standards.

          Table 3.  Allowable pollutant increases above
                    baseline concentrations

Particulate Matter
Annual geometric mean
24-hr maximum
Concentration, yg/m3
Land
Class Area
I II III
5 19 37
10 37 75
NAAQS
Primary Secondary
75 60
260 150
                               694

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                      Table  3.   (Continued)
                                   Concentration.
                                 Land
                              Class Area   	NAAQS	
                              I   II  III  Primary   Secondary
       Sulfur Dioxide
         Annual arithmetic mean  2   20    40     80        60
         24-hr maximum          5   91   182    365       260
         3-hr maximum          25  512   700     —      1300
     Visibility Protection  for Federal Class I Areas.  Section
169 of Part C specifically  addresses the national goal set by the
Congress for the prevention of any future (and the remedying of
any existing) impairment  of visibility in mandatory Federal Class
I areas from man-made  air pollution.  Within 24 months, the Ad-
ministrator will promulgate regulations to assure reasonable pro-
gress toward meeting the  national goal.  The requirements include
existing sources and may  require use of the best available retro-
fit technology.
     Nonattainment Areas.   A new Part D (Sections 171-178) was
also incorporated into the  Clean Air Act Amendments of 1977 to
address alleviation of air  pollution problems in areas where one
or more air pollutants exceed any national ambient air standard.
Theoretically, no new  emission source could be constructed in a
nonattainment area.  Since  this was judged to be an impractical
answer, the compromise solution was to require the "lowest
achievable emission rate" (LAER).  This is an even more restric-
tive standard than the BACT specified for prevention of

                                695

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significant deterioration and includes either the most stringent
emission limitation for such source category in any state imple-
mentation plan or the most stringent emission limitation actually
achieved in practice, whichever is more stringent, and in no
event will it be less restrictive than the NSPS is for that source
category.  Like the PSD, this is to be implemented by the indi-
vidual states through the state implementation plans on a case-
by-case basis.  A key provision is that the states are to con-
tinue "reasonable further progress" in order to achieve annual
incremental reductions of the applicable air pollutant, including
such reduction in emissions from existing sources as may be ob-
tained through the adoption, at a minimum, of "reasonably avail-
able control technology" (RACT).
     The above is part of the so-called "offset" approach wherein
reductions are made in existing emissions to permit addition of a
new source, with the additional constraint that an overall de-
crease should be shown.
     In general, designation as a nonattainment area means that
an applicable SIP must be revised to provide for the attainment
of the NAAQS as expeditiously as possible.  The -revised SIP must
require permits for the construction and operation of major new
and modified stationary sources and must prohibit potential new
source construction where emissions would contribute to an in-
crease in pollutants for which a NAAQS was already being exceeded.
                              696

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     The U.S. EPA has just published a list of the NAAQS attain-


ment status of all areas within each state  (U.S. Environmental


Protection Agency, 1978b).


State


     Although the U.S. EPA promulgates national ambient air qual-f


ity standards, states have the privilege of establishing more


stringent standards.  Thirty-three states and the District of Co-


lumbia  have  ambient  air  quality  standards  (AAQS)  that are more


stringent than those of  the  Federal  Government.


     Since the concentrations of nitrogen oxides and  other pol-


lutants other than sulfur oxides and particulates, for which  .


there are AAQS, are  only marginally related to the quality of


coal prepared or burned, emphasis has been placed on  the standards


for sulfur dioxide and particulate matter  (total suspended par-


ticulates) .  Those states with more stringent AAQS are Alaska,


Arizona, California, Connecticut, Colorado, Delaware, Florida,,


Georgia, Hawaii, Indiana, Kentucky, Louisiana, Maine, Maryland/


Minnesota, Mississippi, Missouri, Montana, Nevada, New Hampshire,


New Mexico, New York, North  Carolina, North Dakota, Ohio, Oregon,


South Dakota, Tennessee, Vermont, Washington, West Virginia, Wis-


consin, and Wyoming  (Figure  1).


                   Water Pollution Regulations
                                      i   i

Federal


  .   There are no national ambient water quality regulations


analgous to those for air; water pollution  is regulated
                               697

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Figure 1.  Map showing states with more stringent AAQS than NAAQS,

-------
nationally on the basis of emissions (termed effluents in the



case of water).



     Effluent Guideline Limitations.  The enabling Act providing



the authority to establish effluent limitations was the Federal



Water Pollution Control Act (FWPCA) amendments of 1972 (P.L. 92-



500).  Basic effluent limitations have now been promulgated for



numerous industries; others have been challenged by the affected



industries and are still in abeyance pending further development.



The FWPCA was further amended in 1977 (P.L. 95-217).  Effluent



guidelines are presently based on the best practicable control



technology currently available  (BPCTCA), which was to have been



achieved by July 1, 1977.  By July  1, 1983, effluent guideline



limitations were to have required the application of the best



available technology economically achievable  (BATEA).  The 1977



amendments have extended this date  a year to July 1, 1984.



     Effluent guidelines are also being promulgated for new



sources.  These new source performance standards for wastewater



effluents are intended to be the most stringent standards applied.



     Federal control of water pollution sources associated with



coal preparation and handling is achieved through the issuance to



each discharger of NPDES  (National  Pollutant Discharge Elimina-



tion System) permits which contain  limits on  specific pollutants



in  the effluents.  Effluents from  coal cleaning are regulated  as



a part of the coal mining point  source category  (40 CFR,  Part



434).  This category includes "associated areas"  such as  the



plant yards, immediate access roads,  slurry ponds,  drainage
                               699

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ponds,  coal refuse piles,  and coal  storage piles and  facilities.

Regulations have  been divided into  two groups—one for acidic

and one for alkaline wastes.   Regulations for  existing  plants

(U.S.  Environmental Protection Agency, 1977d)  and proposed new

source  performance standards  (U.S.  Environmental Protection' Agen-

cy, 1977e)  are  summarized  in  Table  4.   Final regulations  for

BATEA  effluent  limitations have not yet been promulgated.


   Table 4.  Effluent limitations for coal preparation  plants
         Effluent
      Characteristic
                          Acidic  Wastes
                                      (a,b)
                   Alkaline Wastes
                                  (a)
 Daily
Maximum
          30-Day
          Average
 Daily
Maximum
30-Day
Average
 TSS, ing/1
 Iron, toal, mg/1
 Manganese, total, mg/1
 PH
 TSS, mg/1
 Iron, total, mg/1
 Manganese, total, mg/1
 PH
                                       Existing  Sources
 70.0       35.0
  7.0        3.5
  4.0        2.0
      6.0-9.0
                     70.0
                      7.0
            35.0
             3.5
                         6.0-9.0

                                      (c)
Proposed New Source Performance Standards
 70.0       35.0
  3.5        3.0s
  4.0        2.0
     6.0-9.0
                     70.0
                      3.5
            35.0
             3.0
                         6.0-9.0
 (a)  Excess water effluent from a facility designed to contain or treat the
      volume of water from the 10-year, 24-hour precipitation event is not
      subject to limitations.

 (b)  pH may be slightly exceeded to achieve manganese limitation, up to
      9.5.

 (c)  No discharge of pollutants permitted from facilities which do not re-
      cycle wastewater for use in processing.
                                  700

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     Toxic Pollutants.  The Clean Water Act of 1977 introduced a
new requirement for the control of toxic pollutants that are re-
quired to be limited by the application of the best available
technology economically achievable.  The initial list of toxic
subatances and families of substances contained those identified
in the consent decree between the U.S. EPA and the National Re-
sources Defense Council (NRDC).  This list, shown in Table 5 (U.S.
Environmental Protection Agency, 1978c), comprises principally
organic compounds thought to have no connection with coal clean-
ing.  This li.st has now grown into the current 129 "priority pol-
lutants" of which 24 have been tentatively identified as existing
in wastewater from some coal cleaning plants  (Randolph, 1978).
     However, the listing in Table 5 of a few inorganic compounds
(arsenic, beryllium, lead, etc.) would seem, by definition, to
place them in the category of pollutants of concern to the coal
cleaning industry.  No regulations or proposed regulations have
yet been published and the potential effects of such limitations
of the "priority pollutants" on coal cleaning operations would be
speculative at this time.
     Water Quality Criteria.  While ambient air quality standards
are set at the Federal level, water quality standards are pri-
marily a state responsibility.  The only existing Federal water,
quality standards are those for drinking water, applicable to
public (community) water supplies.  Maximum contaminant levels in
public water supplies have been set for contaminants associated
                               701

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                  Table  5.   Pollutants  being considered  for
                               effluent  limitations
       1.   Aoenaphthene
       2.   Aorolein
       3.   Aorylonitrile
       4.   Aldrin/Dieldrln
       5.   Antlnony and compounds

       6.   Arsenic and compounds
       7.   Asbestos
       8.   Benzene
       9.   Benzidene
       10.  Beryllium and compounds

       11.' Cadmium and compounds
       12.  Carbon tetraohloride
       13.  Chlordane
       14.  Chlorinated benzenes
       15.  Chlorinated ethanes

       16.  Chloroaltcyl ethera
       17.  Chlorinated napthalene
       18.  Chlorinated phenols
       19.  Chloroform
       20.  2-ohlorophenol

       21.  Chromium and compounds
       22.  Copper and compounds
       23.  Cyanides
       24.  DDt and metabolites
       25.  Dlohlorobenzenes

       26.  Dlohlorobenzidlne
       27.  Dlchloroethylenes
       28.  2,4-dlohlorophenol
       29.  Diohloropropane and dichloropropene
       30.  2,4-dimethylphenol

       31.  Dinitrotoluene
       32.  Diphenylhydrazine
       33.  Endoaulfan and metabolites
       34.  Endrin and metabolites
       35.   Ethylbenzene                  	
 36.  Fluoranthene
 37.  Raloethers
 38.  Malomethanes
 39.  Heptachlor and metabolites
 40.  Hexachlorobutadiene

 41.  Hexachlorocyclohexane
 42.  Hexachlorocyclopentadlene
 43.  Isophorone
 44.  Lead and compounds
 45.  Mercury and compounds

 46.  Naphthalene
 47.  Niokel and compounds
 48.  Nitrobenzene
 49.  Kitrophenols
 50.  Nltrosamines

 51.  Pentaohlorophenol
 52.  Phenol
 53.  Phthalate esters
 54.  Polychlorinated biphenyla (PCB's)
 55.  Polynuclear aromatic hydrocarbons

 56.  Selenium and compounds
 57.  Silver and compounds
 58.  2,3,7,8-Tetrachlorodibenzo-p-dioxin
 59.  Tetrachloroethylene
 60.  Thallium and compounds

 61.  Toluene
62.   Toxaphene
63•   Trichloroethylene
64.   Vinyl chloride
65.   Zinc and compounds
with  coal and  coal  cleaning  activities:  arsenic,  barium, cadmium,

chromium, fluoride,  lead,  mercury,  nitrate,  selenium,  and silver.

       Federal water  quality criteria  (guidelines)  have  recently

been  revised and expanded  and published  by the  U.S.  EPA  (U.S.

Environmental  Protection Agency,  1976);  while these  criteria  do

not have  direct regulatory application,  the  states are expected

to  adopt  these  when  implementing  state water quality regulations.
                                        702

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Criteria are presented for water quality which will provide for
the protection and propagation of fish and other aquatic life and
for recreation in and on the water.  Criteria are also presented
for domestic water supply quality to protect human health.
State
     The situation on control of water pollution by the states is
analogous to that for air pollution.  Emission standards  (efflu-
ent guidelines) are established on a national level by the U.S.
EPA, but their implementation is regarded as a state responsi-
bility.  The FWPCA (P.L. 92-500} provides for the reduction of
duplicate laws by delegating permit issuance authority to the
states.  Delegation of authority takes place when a state demon-
strates that it has legal capability and resources to operate the
program as envisioned by that Federal law.  The states of Colo-
rado, Indiana, Kansas, Maryland, Missouri, Montana, North Dakota,
Ohio, Virginia, Washington, and Wyoming are delegated NPDES-
issuing states.  The effluent limitations vary among the dele-
gated and nondelegated states.
     Water pollution control enforcement is based on effluent
standards rather than stream quality, and plant discharges must
be within certain limits prescribed for each industry.  The ob-
jective of such control systems is to achieve or maintain ambient
water quality standards that are primarily a state responsibility.
If these are not achieved by compliance with effluent standards,
more stringent limits may be applied.
                               703

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                      Solid Waste  Regulations
Federal
     Prior to October 21, 1976, protection  of  the  environment
from pollution originating from the  land disposal  of  solid wastes
was provided by the  Solid Waste Disposal Act of  1965  (P.L. 89-
272), as amended by  the Resource  Recovery Act  of 1970 (P.L.  91-
512).  Federal guidelines for  the land disposal  of solid wastes
are given in Title 40 CFR, Part 241  (U.S. Environmental Protec-
tion Agency, 1977f).
     Pursuant to Section 211 of the  amended Solid  Waste Disposal
Act, the guidelines  are mandatory for Federal  agencies and are
recommended for state, interstate, regional, and local govern-
ment agencies for use in their solid waste  disposal activities.
However, these are only guidelines and do not  establish new  stand-
ards but set forth requirements and  recommended  procedures to en-
sure that the design,  construction,  and operation  of  the land dis-
posal site is environmentally acceptable.   The thrust of Part 241
is directed toward regulation of  sanitary and  municipal wastes;
mining wastes are esentially ignored.
     The management  of solid and  hazardous  wastes  entered a  new
era on October 21, 1976, upon passage of the comprehensive Re-
source Conservation  and Recovery  Act (RCRA) of 1976 (P.L. 94-
580).   Although the  actual implementation of this  Act has not yet
occurred, it is already clear that management  of such wastes will
be revolutionized by the specific regulations  currently being
drafted by the U.S.  EPA.
                               704

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     The introductory section of the Act describes the Federal
role as one of providing financial and technical assistance and
leadership in the development, demonstration, and application of
new and improved methods of waste management.  In practice, it
appears that guidelines and regulations will be developed by the
U.S. EPA for adoption and promulgation by the states, possibly in
a fashion similar to the SIP's used for air pollution control.
The individual states would enforce their adopted regulations.
Some of the general provisions of the Act are:
     •  The U.S. Environmental Protection Agency is to issue
        guidelines within 1 year for defining sanitary land-
        fills as the only acceptable land disposal alterna-
        tive that can be implemented; open dumps are to be
        prohibited.
     •  Within 1 year, the U.S. EPA will develop and publish
        suggested guidelines for solid waste management.
     •  Within 18 months, the U.S. EPA will promulgate cri-
        teria for identifying hazardous waste, standards for
        generators, transporters, and for treatment, storage,
        and disposal of hazardous wastes.
     •  Permit programs are to be managed by the states but
        under minimum guidelines to be provided by the U.S.
        EPA.
     •  Each regulation promulgated will be reviewed and,
        where necessary, revised not less than every 3 years.
                              705

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     The development of specific solid waste regulations is ap-
preciably behind schedule and discussion of possible requirements
for coal cleaning refuse is, accordingly, unavoidably specula-
tive.  However, the indications are that coal cleaning refuse may
be classified as hazardous waste, a case which would then involve
the most restrictive provisions of the Act, including permit ap-
plication, monitoring, record-keeping, and reporting.
     The Geological Survey of the U.S. Department of the Interior
has established regulations for the disposal of wastes from coal
preparation plants located on land associated with mining (U.S.
Department of the Interior, 1977).  Preparation is defined as any
crushing, sizing, cleaning, drying, mixing, or other processing
of coal to prepare it for market.  The operator is required to:
     "dispose of all waste resulting from the mining and
     preparation of coal in a manner designed to minimize,
     control, or prevent air and water pollution and the
     hazards of ignition and combustion".
Additionally, more specific requirements are given for waste pile
construction, covering and revegetation, and settling ponds.
State
     A few states have solid waste disposal regulations directly
applicable to coal preparation or consumption.  The various states
have general regulations covering solid waste management, solid
waste disposal, and solid waste disposal areas (landfills, sani-
tary landfills, etc.).  Solid wastes are not to be disposed of in
such a manner as to or in those areas where they could endanger
                                706

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human health and plant or animal life or contribute to air pollu-
tion.  Locations of these disposal areas are also to be such that
they pose the least possibility of surface or groundwater con-
tamination.  The provisions of the Resource Conservation and Re-
covery Act of 1976 will allow definitive guidelines to be estab-
lished by each state for the storage and disposal of solid wastes,
including those generated from coal preparation and consumption.
                               707

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                            REFERENCES


Cleland, J. G., and  G.  L.  Kingsbury.   1977.   Summary  of  key  fede-
     ral regulations and criteria  for  multimedia  environmental
     control.  Draft report to  U.S. Environmental Protection
     Agency, Research Triangle  Institute,  Research Triangle  Park,
     North Carolina.  132  pp. + appendix.

Ehrlich, p. R., A. H. Ehrlich,  and J.  P. Holdren.   1973.   Human
     ecology:  problems and solutions.  W. H.  Freeman and  Com-
     pany, San Francisco,  California.   304 pp.

Energy and Environmental Analysis,  Inc.  1976.  Laws  and regula-
     tions affecting coal  with  summaries of  federal,  state,  and
     local laws and  regulations pertaining to  air and water  pol-
     lution control, reclamation,  diligence, and  health  and
     safety.  DOI/OMPRA/CL-76-01,  report to  U.S.  Department  of
     the Interior, Office  of Mineral Policy  and Research Analy-
     sis.  200+ pp.

Ewing, R. A., D. A.  Tolle,  S. Min,  G.  E. Raines,  and  V.  L. Holo-
     man.  1977.  Development of environmental assessment  cri-
     teria.  Draft report  to U.S.  Environmental Protection Agen-
     cy. Battelle's  Columbus Laboratories, Columbus,  Ohio  (April
     8, 1977).  46 pp.

Ewing, R. A., G. Raines, P. Van Voris, and B. Cornaby.   1978.
     Development of  environmental  assessment crite'ria.   Final
     draft report to the U.S. Environmental Protection Agency.
     Battelle's Columbus Laboratories, Columbus,  Ohio (October
     1978).

Garvey, G.  1972.  Energy,  ecology, economy.  W. W. Norton and
     Company, Inc.,  New York.   235. pp.

Hardin, G.  1969.  Population,  evolution, and birth control, 2nd
     edition.  W. H. Freeman and Company, San Francisco, Cali-
     fornia.   386 pp.

Harrison, J.  W.   1978.  Standard support plan for  technologies
     for coal cleaning.   Draft  report to Research  Triangle Inst-
     tute.  39 pp.

Randolph, K.  B., L.  B.  Kay, and R. C.  Smith, Jr.   1978.  Charac-
     terization of preparation  plant wastewaters.  Paper pre-
     sented at symposium on Coal Cleaning To Achieve  Energy En-
     vironmental Goals  (September  11-15, 1978), Hollywood,
     Florida.
                               708

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U.S. Department of Commerce.  1977.  Projections of the popula-
     tion of the United States:  1977 to 2050.  Series P-25,  No.
     704 (July 1977).   Bureau of the Census.

U.S. Environmental Protection Agency.  1976.  Quality criteria
     for water.  EPA 440/9-76-023.  U.S. Environmental Protection
     Agency, Washington, D.C.  501 pp.

U.S. Environmental Protection Agency.  1977a.  Code of federal
     regulations, 40 protection of environment.  Revised as of
     July 1, 1977, Office of the Federal Register, National Ar-
     chives and Records Service, General Services Administration,
     Washington, D.C., Part 50, National Primary and Secondary
     Ambient Air Quality Standards,  pp. 3-13.

U.S. Environmental Protection Agency.  1977b.  Code of federal
     regulations, 40 protection of environment.  Revised as of
     July 1, 1977, Office of the Federal Register, National Ar-
     chives and Records Service, General Services Administra-
     tion,  Washington, D.C., Part 60, Subpart Y, Standards of
     Performance for Coal Preparation Plants,  pp. 57-58.

U.S. Environmental Protection Agency.  1977c.  Lead:  proposed
     national ambient air quality standard.  42 FR 63076-63094
     (December 14, 1977).

U.S. Environmental Protection Agency.  1977d.  Code of federal
     regulations, 40 protection of environment.  Revised as of
     July 1, 1977, Office of the Federal Register, National Ar-
     chives and Records Service, General Services Administration,
     Washington, D.C., Part 434, Coal Mining Point Source Cate-
     gory,   pp. 685-689.

U.S. Environmental Protection Agency.  1977e.  Coal mining point
     source category.  41 FR 21380  (April 26, 1977).

U.S. Environmental Protection Agency.  1977f.  Code of federal
     regulations, 40 protection of environment.  Revised as of
     July 1, 1977, Office of the Federal Register, National Ar-
     chives and Records Service, General Services Administration,
     Washington, D.C., Part 241, Guidelines for the Land Disposal
     of Solid Wastes,  pp. 529-538.

U.S. Environmental Protection Agency.  1978a.  Part V.  electric
     utility steam generating units, proposed standards of per-
     formance and announcement of public hearing on proposed
     standards.  FR 43(182):42154-42184.

U.S. Environmental Protection Agency.  1978b.  National ambient
     air quality standards, states attainment status.  43 FR
     8962-9059  (March 3, 1978).
                                709

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U.S. Environmental Protection Agency.  1978c.  Publication of
     toxic pollutant list.  43 FR 4108 (January 31, 1978).
                             710

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                   DEVELOPMENT OF ENVIRONMENTAL ASSESSMENT
                    CRITERIA FOR COAL CLEANING PROCESSES

         R.  A.  Swing1, P. Van Voris1, B. Cornaby1, and G. E. Raines2

                     ^attelle's Columbus Laboratories
                              Columbus, Ohio

                         2Raines Consulting, Inc.
                              Columbus, Ohio


                                 ABSTRACT


     There are four interrelated  activities  associated with the  environmental
impact assessment of coal cleaning  facilities.   The  first  step is  documentation
of chemical characteristics of the  waste stream,  with the  physical transport
and distribution characteristics  of the pollutants of concern in air, water,
and land being the next  step.   This is  then  followed by  estimations  of  the
biological transport of  those  pollutants within the  ecosystem where  the
pollutants may reach any number of  receptor  organisms,  including man.   The
fourth and final activity estimates health and  ecological  effects  relative  to
the dosages predicted by the above  interactions.

     •  Overall Methodology

        The pollutants most needing control  need to  be  identified, either
        because of the quantities emitted or their toxicities, or  both.
        Decision criteria are  needed to determine the relative priorities
        to be assigned  to controlling specific  pollutants.

        The environmental assessments to be  performed will require quanti-
        tative emission  and distribution data for specific coal  cleaning
        plant configurations,  coal  types,  geographic locations,  etc.   In
        developing and illustrating assessment  criteria  and methodologies,
        this study utilizes approximations of emissions  and dilutions  such
        as might be associated with a hypothetical coal  cleaning plant.

     •  Physical Transport  and Partition Functions

        Estimates of environmental  concentrations of pollutants  in all
        three media - air,  water, and land - are needed.   This estimation
        initially involves  physical transport and dispersion; the  approaches
        to modeling physical distribution are discussed.

     •  Biological Transport Within Ecological  Systems

        Ecological transport and  distribution has not been adequately
        investigated; there are large gaps in the data  for many  elements
        and many species.   Qualitatively,  the pathways  and mechanisms  for
        dispersion, accumulation, and magnification  have been identified;

                                    711

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        the  problems  arise in attempts to quantify  the rates of
        movement based on these mechanisms.  The approach to these
        problems and  several illustrative examples  are described.

     •  Establishing  Goals Based on Estimated Permissible Concentrations (EPC's)

        One  of the most critical information needs  is dose-response data
        on the health and ecological effects of individual pollutants and
        their mixtures.  Then, estimated permissible concentrations (EPC's)
        can  be derived.  Also needed are improved methods for converting
        toxicological data to the threshold effects levels represented by
        EPC's, and biologically supported safety factors  for incorporation
        into the formulae.  The complexities of deriving  EPC's on the basis
        of available  toxicological data are discussed.
                            INTRODUCTION


      As increasing  reliance is  placed upon coal  as an energy

source, the need  to minimize the  environmental  impacts resulting

from pollutant emissions will become more and more important.

Recognizing this  need,  the U.S. EPA has initiated a number of

programs to (1) assess  the environmental impacts of fossil fuel

energy processes  and (2) identify problem areas  requiring further

research and development.  Battelle-Columbus has been investiga-

ting the environmental  assessment of coal cleaning processes

since the fall of 1976.   The following describe  some of the acti-

vities in the area  of development of assessment  methodology and

assessment criteria, including decision criteria to determine  the

relative priorities  to  be assigned to controlling specific pollu-

tants  so that attention can be focused on those  most needing it.

     A fundamental criterion for  assessing the environmental

impacts of pollutants associated  with coal cleaning is the
                                 712

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relationship of the permissible environmental concentrations of
pollutants to those which can or do occur.  Elucidating this rela-
tionship involves four interrelated activities illustrated by
Figure 1.  The first step is documentation of chemical character-
istics of the waste streams with the physical transport and dis-
tribution characteristics of the pollutants of concern in air,
water, and on land being the next step.  This is then followed by
estimations of the biological transport of those pollutants within
the ecosystem where the pollutants may reach any number of recep-
tor organisms, including man.  The fourth activity estimates
health and ecological effects relative to the dosages predicted
by the above interactions.  All four activities provide input for
a prioritization of pollutants.

                  WASTE STREAM CHARACTERIZATION

     The pollutants which most need control, either because of the
quantities emitted or their toxicities, or both, need to be iden-
tified.  The pollutants directly resulting from coal cleaning are
primarily inorganic compounds associated with the ash fraction;
water will be the major receptor of these pollutants.  Operations
producing major emissions of air pollutants are infrequent in
coal cleaning.  The largest air emissions will arise as particu-
lates from thermal dryers and as fugitive dust from coal storage
and refuse piles and from coal handling.
     Data from the U.S. Bureau of Mines, the U.S. Geological Sur-
vey, and other sources were utilized to develop lists of potential
                               713

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                     WASTE STREAM CHARACTERIZATION

                 Update and refine existing lists of
                   pollutants
                 Estimate  pollutant quants, and cones.
                          PHYSICAL TRANSPORT

                    Determine partition functions
                    Estimate environmental cones.—
                      air, water, land
                        BIOLOGICAL TRANSPORT

                   Determine pathways and mechanisms
                   Quantify
   POLLUTANT PRIORITIZATION

Establish decision criteria
  for prioritising pollutants,
  sources, and problems
ESTABLISH GOALS

Convert toxicological data to
est. permissible cones. (EPC's)


	


 Existing BCL Lilts
 OSBM  Data
 USGS  Data
 Coal  Cleaning
  Technol. Asset*.

 Plant configuration
 Coal  type
 Fraetionation factors
 Process conditions
Existing dispersion
  models
Published literature
Existing transfer models
                                                                  Toxicological data

                                                                  Multimedia env. goals
                                                                    (MEG'S)
                                                                  Mini acute toxicity
                                                                   •ffluents (MATE'S)
           Figure  1.   Environmental assessment scheme.
                                       714

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pollutants of concern.  Such lists tend to become inordinately
long, if large doses of judgment are not used.  Thus, a selected
"Priority 1" list of 51 elements and 23 substances or groups of
substances was selected judgmentally from larger lists for inves-
tigation (Battelle, 1977).  The need for further pruning and pri-
oritization of pollutants will be discussed later.  The waste
streams need also to be characterized as to pollutant quantities
and concentrations to provide the data needed to estimate environ-
mental concentrations.  Pollutant emissions are dependent on a
number of governing factors, including coal types, fractionation
factors, process conditions, and geographic location.  Ultimately,
these data will come from specific measurements; but in the inter-
im, these have to be estimated.
     The various lists of potential pollutants identify those
pollutants which may be of concern in coal cleaning, provided
that they are present and emitted above some yet undefined rate
of release and/or concentration.  By virtue of its origin, coal
has been found to contain nearly every naturally-occurring element,
The concentrations of these elements in coal vary widely.  Many of
these elements, e.g., arsenic, beryllium, cadmium, lead, and mer-
cury are recognized as toxic substances.  The ranges of pollutant
concentrations characteristic of coals provide some information on
their presence, but none on their possible emissions.  Input data
required to estimate emissions include, first, information on the
process steps embodied in the cleaning flowsheet.  Many alterna-
tives and combinations of alternatives are possible in crushing,
                               715

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sizing, and washing coal, and in separating coal from refuse.  The
actual combination of process elements will influence the degree
of pollutant emissions, but not the kind.  Thus, for purposes of
developing assessment criteria and methodology, reasonable approx-
imations of a generic process flowsheet will suffice, and are
used in this discussion.
     The second item needed for the estimation of emissions is
information on partitioning of the pollutants or "fractionation
factors", i.e., the distribution of substances in raw coal to
another fraction or phase as the coal passes each process step.
Generally, data are needed for each pollutant which give the frac-
tion of the pollutant in the raw coal which distributes to the
refuse, clean coal, bottom ash, fly ash, and the atmosphere.
     Estimates of the distribution of elements between clean coal
and refuse can be developed using float-sink or "washability"
data, which have been determined experimentally for many coals.
Gluskoter et al. (1977) have intensively examined this aspect of
coal cleaning, concentrating on Illinois Basin coals, but also
including other eastern coals.
     If it is desired to base the calculations on a specific coal,
for which washability data are available, fractionation factors
calculated for that coal can be used.  A simple computer program
has been developed and tested which permits estimation of frac-
tionation factors for elements as a function of specific gravity
cutoff points and/or percentage yield.
                              716

-------
     "Fractionation factors" are also available from Klein, et al.
(1975)  and others for the partitioning of elements upon combus-
tion in a boiler.  These can be used to estimate losses to the
atmosphere from the thermal drying of cleaned coal.  For parti-
tioning of elements between coal and the atmosphere during trans-
porting, handling, and storage, "fractionation factors".would
correspond to emission factors, such as have been estimated by
the U.S. EPA (1973) and others, for example (Blackwood and
Wachter, 1977).  Analogous "emission factors" have yet to be
developed for losses of pollutants leached out from coal storage
piles,  ash ponds, etc.
     Values of emission concentrations are required as input to
dispersion models to permit the calculation of ground level con-
centrations  (GLC) for air pollutants and surface water concentra-
tions  (SWC) for water pollutants.  A simplified preliminary mater-
ial balance model has been developed covering the direct process
steps  from raw coal to combusted ash, illustrated by Figure 2.
The incidental losses to air and water arising from transporta-
tion,  handling, and storage are not included in this preliminary
model, but can readily be included when data become available.
The model, which  is normalized to a combustion output of 10  Btu,
can provide estimates of absolute emissions and average concentra-
tions  of any number of trace constituents  in  (1)  refuse,  (2) ther-
mal dryer atmospheric discharge,  (3) stack discharge from  combus-
tion,  and  (4) ash flow based on composite  flows,  given an  analysis
for the starting  raw coal.
                               717

-------
                        165 Ibs
                         Water
                           I
                                  0.65 MSCF
                                Thermal Dryer
                               Stack Discharge
               11.44 MSCF
                Flue Gas
                                      t
oo
93.27 Ibs
 Raw Coal
                         Physical
                         Cleaning
73.93 Ibs
 Cleaned
  Coal
Combustion
                                                      t
10° Btu
Output
{ 120 kwhr
Electricity)
          165 Ibs
        Contaminated
           Water
                 _184 Ibs
                  Wet Refuse
     11.06 MSCF
         Air
   9.39 Ibs
      Ash
                            1
                        18.7 Ibs
                       Dry Refuse
                 Figure 2.  Flow quantities for coal cleaning/power plant complex

-------
     The model has been derived,  programmed, and run with example

cases, using a composite fuel analysis of 68 percent coal from the

Helvetia mine and 32 percent from the Helen mine, approximating

one possible coal feed, to the Homer City advanced coal cleaning

facility.
                       PHYSICAL TRANSPORT


     Pollutants emitted in the course of coal cleaning, handling,

transportation, storage, and combustion can both accumulate and

disperse, in both a physical and biological sense, depending upon

the characteristics of the pollutant and the compartment.  Bio-

logical transport and  fate are discussed in the  following section.

In this section, modeling of the preceding physical transport and

dispersion are discussed.  The general need for  modeling is to

make estimates of the  concentrations of trace pollutants in envi-

ronmental media as a result of operation of a coal cleaning plant.

No regulations or design criteria are available  yet for most of

these, although regulations will be proposed and promulgated by

EPA within the next year or two for a number of  toxic  pollutants

which may affect coal  cleaning plants.

      In  succeeding paragraphs, modeling approaches are discussed

relative to  surface water, groundwater, air, and porous media.

Generally, the air pollution model  should  account  for  deposition,

both wet and dry, providing  one  input  to  surface water and  soils.

Surface  water run-off  will pick  up  material in  the upper soil

layer.   The  coal  pile  will be  leached  from precipitation and also

generally carried into surface water.   Leaching and leakage
                                719

-------
 through  sedimentation pond bottoms will generally contribute  to
 groundwater pollution, although  the movement of some pollutants
 through  the subsoil and into the groundwater requires years be-
 cause of adsorption of materials on soils.  The refuse area,
 usually  some kind of a fill, will be leached by the downflow  of
 water from precipitation and surface flow, contributing to both
 stream pollution and groundwater pollution.  The rationale that
 should be incorporated in the modeling approach is to build a
 capability of evaluating individual coal cleaning complexes,
 either existing or under design.  This approach is recommended
 because  the many different characteristics, e.g., meteorology,
 topography, stream geometry, soil, and groundwater characteristics
 required to characterize a given complex, vary widely from one
 plant to another, making generalizations risky at this time.
     On  the other hand, the objective of the present investigation
 is to develop criteria and associated methodologies for their
 application rather than to estimate site-specific environmental
 impacts  for a given complex,  The solution would seem to be to
 include the necessary provisions in the models for the multipli-
 city of detailed parameters which will ultimately be required, but
 to use nominal values, or ranges, or even possibly "worst-case"
 estimates, for a hypothetical site in the developmental phase.
     Validation is an important aspect of model development,  and
 should be planned for, utilizing one of the coal cleaning sites
chosen for field data acquisition.  Field data will permit valida-
tion and calibration of the models and suggest their application
                               720

-------
for future sites.  However, it is not possible within the time
frame of the present program to wait until field data are avail-
able to initiate model development.  For that matter, it is not
desirable to wait because modeling will illustrate the required
data which need to be gathered and will give preliminary evalua-
tions, using data that are available in the literature from other
area.
                  Air Dispersion of Pollutants
     The concentration of key pollutants in the thermal dryer
atmospheric discharge and in the flue gases from combustion of the
cleaned coal will provide input for calculations of atmospheric
dispersion to yield ground level concentrations.  The basic pur-
pose of the dispersion calculation is to provide an estimate of
the dilution factor which, when divided into the stack emission
concentrations, will yield ground level concentrations.
     Two basic models are required, depending on whether the pol-
lutant is associated with large or small particles, where 100 mi-
crons is a typical dividing point.  Large particles tend to
deposit on surfaces close-in such that the air concentration is
depleted as distance from the stack increases.  The concentration
of smaller particles is reduced only by dispersion.
     Simplified dispersion models, as typified by that presented
by Turner (1970), are availabe to consider stack heights and diam-
eter, stack gas temperature and exit velocity, and ambient air
temperature and wind speed.  Calculations would be performed for
different weather categories.  Multiple sources can be considered
                               721

-------
to include the effects of more than one stack if distance between
stacks is large enough to merit this refinement.
     The large particle deposition model requires only the depo-
sition factor, wind speed, and effective stack height.  Deposition
factors are available in the literature for various wind speeds
of interest.
     A fugitive dust emission model, based on the EPA Multiple
Point Source Model (PTMTP), has been used by Battelle to help in
selecting sampling sites at the Homer City coal cleaning plant,
and to project mass atmospheric concentrations.  It is a Gaussian
plume, multiple source model, with a generation function for fugi-
tive emissions dependent on wind speed squared.  Deposition is
accounted for  (but not plume depletion).  The model has been cali-
brated based on field data acquired at Homer City  (Ambrose et al.,
1977) .
                 Water Dispersion of Pollutants
     Two types of effects may need consideration for discharges of
pollutants to water: dispersion and sedimentation of particulate
solids, and dispersion and dilution of soluble pollutants.
     For the estimation of surface water concentrations, the con-
centrations of pollutants and the flows of waste water discharges
are required as input.  Emission sources to be considered include
the waste water discharge from coal cleaning and runoff and per-
colation from coal and refuse storage piles, as well as from ash
ponds at coal cleaning plants and from coal storage piles at user
plants.
                               722

-------
     Sedimentation in settling basins can be modeled by the use
of deposition coefficients.  Since sedimentation requires only a
portion of the pollutant from a water column, a residual concen-
tration remains which is then further diluted by dispersion and
additional sedimentation in streams, etc.  Simplified dispersion
models using point sources of pollutants can be used.  These
models provide a correlation of dispersion coefficient with flow
velocity and stream configuration so that reasonable approxima-
tions for surface water concentrations associated either with a
specific facility or with a generalized case can be calculated
for average flows, low flows, and high flows.  Sedimentation is
incorporated by the use of deposition factors relating sedimenta-
tion rate to concentration of the pollutant in the water body.
Output will consist of sedimentation rate and concentration in
water as a function of position (normally distance downstream)
for each case.  Pseudo-steady state models are believed to be ade-
quate.  With these models, when a change of conditions is encoun-
tered such as a change of release rates or an increase in flow of
the stream, concentrations make a step change from one steady
state to another.  Sediment accumulates on the stream bottom line-
arly with time until such a change in conditions occurs.  Fully
mixed (with stream across section and depth) models are more
appropriate for small narrow streams which are likely to be
around a coal cleaning plant.  These solutions to the transport
equation have been known for years, and they are reasonably appli-
cable for continuously flowing freshwater streams.
                              723

-------
      The  need  for a  sedimentation model  is not certain.   The  U.S.
 Environmental  Protection Agency has promulgated effluent  guide-
 lines for existing coal preparation plants and associated areas
 (U.S.  EPA,  1977a), and also has proposed new  source performance
 standards (U.S. EPA, 1977b), both of which establish upper limits
 of  total  suspended solids  (TSS) of 70 mg/1 (maximum for any one
 day)  and  35 mg/1  (average  of daily values for 30 consecutive  days).
 For new sources these values apply to facilities which recycle
 waste  water for use  in processing (nearly all new facilities  should
 fall  into this category).  A no discharge of process waste water
 limitation  is proposed for new facilities which do not recycle
 waste  water.
      The  definition  of "coal preparation plant associated areas"
 is broad,  including  plant yards, immediate access roads,  slurry
 ponds, drainage ponds, coal refuse piles, and coal storage piles
 and facilities (U.S. EPA, 1977a).  Thus, in order to be in compli-
 ance,  effluent from  all areas of a coal preparation plant, includ-
 ing coal  and refuse  piles, will have to be controlled so  that the
 total  aqueous TSS discharge does not exceed an average of 35  mg/1.
At this concentration, sedimentation probably can be neglected.
                Dispersion Through Porous Media
     Although emission of pollutants to the atmosphere and to sur-
face waters is regulated by the U.S.  EPA, heretofore the  invisible
and difficult-to-measure escape of aqueous pollutants downward
through the soil has essentially avoided regulation.  This situ-
ation  is beginning to change,  and this pollutant transport path
should be considered in regard to environmental criteria  for  coal
                                724

-------
cleaning plants.  As mentioned in the introduction to this sec-
tion, this pollutant release pathway can come into play beneath
storage piles of raw and cleaned coal or refuse, as well as under
refuse ponds.
     Simplified approaches to the adsorption and leaching of pol-
lutants in porous media are available.  Simplified one-dimensional
models are described by Raines  (1966) along with comparisons with
sophisticated results such as computerized finite difference
models with Langmuir adsorption-desorption.  In many cases the
simplified models are quite adequate.  It is recommended that ini-
tial emphasis can be directed toward correlation of data and esti-
mation with these models.
     Groundwater modeling for accurate estimation of flows and
resulting trace contamination is sophisticated and complicated.
A sophisticated approach is not deemed within the scope of this
program at the present time.  Socme experimental data are avail-
able for various trace elements and various  soils.

                      ECOLOGICAL TRANSPORT

     Coal cleaning  facilities have a number  of  potential  sources
of pollutants which include leachate and runoff from coal storage
and  refuse disposal piles/ process wastewater or blowdown from
closed water circuits, and dust and  gases emitted  from  coal  piles,
refuse piles and thermal dryers.  The more apparent  environmental
effects from these  potential  contaminants might be  seen in direct
contact toxicity resulting  from changes  in pH in  the surrounding
                               725

-------
 media,  increasing levels  of sulfate sulfur,  sulfur dioxide,

 nitrate nitrogen and nitrogen oxides,  or resultant chemical

 changes in abiotic components.   These  types  of effects are usua-

 ally  short-term and easily identified.   But,  what happens  to

 those trace elements (e.g., arsenic, cadmium,  and mercury) whose

 release into both terrestrial and aquatic ecosystems  is not quite

 so  apparent?

      This  portion of the  environmental  assessment criteria study

 has focused on  a short list of potentially hazardous  trace con-

 taminants  that  might be released  as a result of coal  cleaning.

 These include elemental,  inorganic, and organic forms of:  ar-

 senic,  beryllium,  cadmium,  iron,  lead,  manganese,  mercury, and

 selenium.   It is well known and documented that these contami-

 nants are  absorbed,  retained, released,  and cycled among the

 biotic  (i.e., producers,  herbivores, omnivores, carnivores, and

 decomposers) and the  abiotic  (i.e., soil, groundwater,  surface

 water,  and  sediment)  compartments  (see  Jackson and Watson, 1977;

 Jackson et  al.,  1978; Huckabee and Blaylock, 1974; Friberg et al.,

 1974; D'ltri, 1972;  and Van Hook  et al.,  1974).   The  structure and

 complexity  of transfer pathways and the matrix notation of the

 typical ecosystems in question are depicted in Figure  2.  For the

purpose of  this  paper, cadmium and mercury are used as examples of

the types of information that are available in Ewing  et al.,  1978.
                                       s
     The toxicity of these contaminants  to living  systems under

certain conditions has been established by other researchers

 (Luckey et al.,  1975).  In addition, biotransformation of some
                              726

-------
                                                            [Fj  (having components
                                                            Fjii and Fi*2) = air-
                                                            borne atmospheric  forc-
                                                            ing function,  and F2  =
                                                            aquatic  input forcing
                                                            function.]
                TERRESTRIAL
                                           AQUATIC
                                          Biological Transport
  Physical
  Transport
  Biological
  Transport
                                                          X'MAN
                                  (a) Indirect ingaatkm resulting from faading habha.
                                  (b) Irrigation, nominal in araa* of groundwatar irrigation.
                                  (c) Surfaca watar intaka.
                                  (d)Drinkingwatarintaka.
                                  • Dominant tyststn transfar.
(The  matrix is de-
fined so that  the
column element is
the donor compart-
ment and the row
element is the re-
cipient. »
                (Man is shown,  but no  data are reported.)

Figure  3.   Compartmental model of  generic  ecosystem and dominant
pathways of pollutant  transport and matrix configuration  of  im-
portant rate transfer  coefficients within  the  generic  ecosystem.
                                       727

-------
contaminants  (i.e.,  mercury)/  as  shown in  Figure  4, can drastically

change  both the availability and  toxicity  of that pollutant.  So,

the ultimate  goal  of transport and fate studies  is to  determine

whether or not toxic concentrations could  be reached through nor-

mal environmental  exposure pathways.   That is, even if the  source

release rates for  a  specific pollutant from a coal cleaning facility

were below the current  Federal regulations,  would the  concentra-

tion of the contaminant ecologically magnify to a point at  or be-

yond the toxic threshold values?
                               Mercuric ion,
                               cheloted cation! and onieni,
                               limple complex**,
                               oxide*, lulpnidei
Bacterial oxidation
Plankton
Plant*
Inorganic
reaction^
        Inorganic reaction!
       'Sunlight
                                   Hg(ll)
                                ial reduction
 Elemental mercury
 a* vapour, liquid
 or dinolute
Hg(0)
              Bacteria
             "Sunlit"


      ^Bacterial reduction
        .Fungi
         Bacterial oxidatior
         Plant!
         Inorganic reaction*
                                    Bacterial lyntheiii
                                    Chelotion
                                         Bacteria,
                                         convention by
                                         organic pxidant!
Organo • mercury
  compound*

R,R'salkyl,oryl,
    mereopto,
    protein, etc.

X » monovalent anion
  eg. halide, acetate,
  etc.
                                     Bacterial lyntheiii
                                     Chelotlon
                                     Organic oxidanti
  Diiproportionation and
   electron exchange
                 Mercuroui Ion,
                 cheloted eationi and anioni,
                 limple complexes
Figure  4.   Cycling of  mercury  interconversions  in nature  (with
permission  from  I. R.  Jonasson and R.  W.  Boyle,  1971).
                                   728

-------
     When magnified  by  an  organism,  concentration  of  a  contaminant
 on  a per gram basis  is  greater  than  that  of  its  source  or donor
 compartments.   The term describing this is ecomagnification which
 is  non-source specific  and includes  all potential  exposure path-
 ways  (ingestion,  inhalation,  adsorption and  immersion)  within the
 ecosystem.   Ecomagnification  is frequently misunderstood as a sim-
 plistic biological phenomenon when,  in fact, it  is quite complex.
 Ecomagnification  is  all  inclusive, whereas the classic  term bio-
 magnification  only considers food ingestion  as the mode of expos-
 ure.  Thus,  the ability  of an organism to accumulate  or magnify
 contaminants depends on  a number of  ecological,  chemical, physio-
 logical, and physico-chemical factors, such  as:
     •  chemical  form of contaminant
     •  concentration of contaminant in soil or  water
     •  interaction with other  trace elements
     •  biotransformation of original elemental  form
     •  soil characteristics and properties
     •  physiological makeup of target organism
     •  complexity of food sources.
     In this study,  the  concentration factors  (i.e.,  percent up-
 take or retention) for the pollutants investigated have been ex-
 tracted from the  available literature for the major ecosystem com-
 partments shown in Figure 3 (see page 16).   Tables 1  and 2 present
 typical data entries for cadmium in  the terrestrial ecosystem and
mercury in the aquatic ecosystem.  Data on cadmium and  mercury were
 selected because  they are the most complete  of all the  pollutants
                               729

-------
                                                 Table  1.   Cadmium uptake
                Sample
                                Source Form
                               Percent Uptake/Retention
                                 (concentration basis)
                                      Reference
•vl
OJ
o
          Soil
Vegetable Crop
Oak Trees

Rabbit
Cow
Grasshopper

Chipping Sparrow

Field Cricket
          Dog
          Wolfe Spider

          Predatory Arthropod

          Earthworm

          Woodlouse
          Arthropod litter
            consumer
                         109CdCl2 in simulated rain
                         115CdCl2 in simulated rain
                        CdClj in simulated rain
Cd in soil
Cd in litter-soil

Cd iron dust
CdCl2 in feed
Cd in vegetation
                                  Wild bird seed soaked in
                                    103Cd solution
                                  Vegetation grown in
                                    I09Cd solution
                              in gaseous form
                        Crickets fed on 109Cd-
                          grown vegetation
                        Cd in prey

                        Cd in soil

                        Cd in litter-soil
                        Cd in litter
Abiotic Components
    98.9 ± 1.2
    85.5
    88.4 ± 2.7
Terrestrial Producers
    141.26 ± 24.0
     34.9 ± 0.5
Terrestrial Herbivores
         -30
           8
        -130
Terrestrial Omnivores
         8

        60.9
                               Terrestrial Carnivores
                                       -40
                                        71.4
                                    124.0 ± 93.5
                               Terrestrial Decomposers
                               1.74 x 103 ± 0.42 x 103
                               1.03 x 103 ± 0.03 x 103
                               4.96 x 102 ± 1.90 x 102
                                     36.8 ± 18.4
                                                            Van Hook et al., 1974
                                                            Huckabee and Blaylock,  1974
                                                            Van Voris et al., 1978
Ratsch, 1974
Jackson and Watson, 1977

Friberg, 1950
Miller et al., 1967
Munshower, 19 72

Anderson and Van Hook, 1973

Van Hook and Yates, 1975
                             Harrison et al., 1947
                             Van Hook and Yates, 1975

                             Watson et al., 1976
                             Van Hook et al., 1974
                             Gish and Christensen, 1973
                             Martin et al., 1976
                             Watson et al., 1976

-------
                                                 Table  2.   Mercury  uptake
                Sample
                                     Source Form
                               Percent Uptake/Retention
                                (concentration basis)
                                                                                                   Reference
OJ
Rooted Plant
  (Elodea densa)

Water milfoil
  (Myfiophyllum speoattat
    specatian L .)
       Goldfish
         (Carassius auratus)

       Snail
      Fish
        (Cambusia affinis)
          and
  solution

organic and inorganic Hg
  in solution
                              HgCl2 in solution

                              ^Hg-tagged fly ash
                              ^Hg-tagged fly ash
                              Hg°  and HgCl2 in solution
   Aquatic Producers
5.19 x 106 ± 3.35 x 106


2.21 x 10" ± 1.76 x 10"



   Aquatic Omnivores

1.14 x 101* i 1.03 x 10*


         0.13

  Aquatic Carnivores

         0.02
        2.1 x  10"
Mortimer and Kudo, 1975

Dolar et al., 1971




McKone et al., 1971

Huckabee and Blaylock, 1974
                                                            Huckabee and Blaylock, 1974
                                                            Schindler et al.,  1977

-------
investigated.  However, similar though less complete, data
entries are available for each of the other six pollutants inves-
tigated for both terrestrial and aquatic ecosystem compartments
(Ewing et al.,  1978).
     The ultimate goal was to identify likely distribution fac-
tors and supply much needed input data for simulation models
describing the transport and fate of these pollutants.  The com-
puter simulation of transport and fate would enable scientists to
compare the computer-predicted, long-term body burdens with
reported toxic concentrations for each of the pollutants.  As is
evidenced in Tables 1 and 2 (pages 19 and 20) there are some indi-
cations that both cadmium and mercury have the propensity to eco-
magnify.  However, the data are extremely variable and depend on
the above listed  (see page 18) influencing factors.  Unfortunately,
the need to use computer simulations and then compare the results
to reported toxic effects values is currently ahead of the data
base.  The data required to accurately calculate the rate trans-
fer coefficients currently are not available in the literature.
Investigators, in general, fail to consider or report:   (1) the
measurement of major parameters affecting transport and fate,
(2) partitioning data into specific exposure sources  (i.e., food
source, inhalation, direct absorption),  (3) chemical form of the
pollutant, and/or  (4) time duration of the experiment.  Therefore,
the use of computer modeling to accurately predict ecological
transport and fate of pollutants is currently beyond the state-of-
the-art.
                                732

-------
     The resulting recommendations for future research fall into



three major categories.  First, there is an immediate need to con-



duct research designed to determine the relative importance of



each exposure pathway for a series of populations within each



compartment.  A series of closely controlled experiments could be



designed to estimate these values.  This would enable concentrated



effort to be focused on the second major category which is the



determination of the rate transfer coefficients for chemical forms



for each dominant pathway.  The third category of recommended re-



search is simulation model development and field test validation



of the forecasts obtained from such models.  An orderly timing of



these research recommendations could produce an accurate, short-



term index of anticipated impact from released trace contaminants



from a coal cleaning facility for the environmental assessment



program.





      ESTIMATION AND RATIONALIZATION OF BIOLOGICAL EFFECTS






     Many species of plants, animals (including man), and micro-



organisms will be found living near coal cleaning facilities.



Many individuals will be exposed to pollutants from the facili-



ties'  emission streams.  If pollutants are discharged to the at-



mosphere, toxic materials may be transported, as indicated earlier,



and be breathed by animals and plants.   Waterborne chemicals can



be transported and later affect aquatic plants, animals, and mi-



croorganisms.  Nondegradable pollutants can be leached from land-



filled materials and be taken up by crop species to man as well
                               733

-------
 as other receptor organisms and enter food chains.   Previous sec-
 tions have dealt with our knowledge of such transfers for the
 short list of priority pollutants.   However,  exposure alone does
 not Assure an effect.   Thus,  the problem becomes one of determin-
 ing if a specified concentration of pollutants  can  harm living
 organisms in a measurable and significant way once  transferred  to
 the organisms.
      Documenting and  evaluating biological effects  ideally should
 precede setting of environmental goals and development of control
 technology for coal cleaning  facilities.   The burden of proof for
 establishing environmental  goals rests with health  and ecological
 effects data;  i.e., if no problem exists,  there  is  no need for  a
 solution.   Data need  to be  sound, complete, rigorous,  and they
 must  be interpreted correctly to support  environmental goals  and
 recommendations for further development of control  devices for
 coal  cleaning  facilities.  More  details on this  point and the
 types of  biological effects are  found  in  Cornaby et al.,  1978.
 Unfortunately,  biological effects data are not only relatively
 sparse  compared  to those needed  for adequate  assessments  but
 also  are  typically laboratory results  rather  than real  results
 from  practice.   Thus,  the following material was developed as
 another step in providing the necessary feedback for prioritiz-
 ing pollutants for purposes of control  strategies,  i.e., which
 substances need how much control in order  to protect human health,
non-human populations, and ecological systems.
                              734

-------
     Most biological effects data are obtained in the laboratory
and need to be extrapolated to "real world" situations.  Extrapo-
lation is the process of inferring or extending a known toxico-
logical response into an unknown area.  Conjectural knowledge of
the unknown area is developed based on assumed continuity, cor-
respondence, or other parallelism between it and what is known.
Often/ biological effects need to be extrapolated from (1) labo-
ratory to field—many differences, including lack of transfer co-
efficients, make this difficult,  (2) one species to another—no
two species are alike,  (3) one medium to another—drinking is  not
the same as breathing, and  (4) one life stage to another—ranges
of sensitivity may differ by four orders of magnitude.  In prac-
tice, biological effects data are collected from a few life stages
of a few species for a few routes of entry in a few controlled
conditions.  On the other hand, the real world situation around a
coal cleaning facility contains thousands of species in many
stages of growth, all of which may be continuously exposed to
various types of doses.  Extrapolation is almost as much an art
as a science; almost everyone is aware of this.  Clearly, ex*-
trapolation must be done with caution.
     Despite the technical difficulties involved in estimating
permissible concentrations of toxicants to organisms, approaches
are available for dealing with the problem.  There are formulae—
some of them developed by or for  the U.S. EPA  (Handy and  Schindler,
1975) .  The formulae have two basic parts:  a dose/response part
and an adjustments part.  The dose/response generally consists of
                              735

-------
one of the typical laboratory effects measurements:  LD50, LDLQ,
and TL -96 hr*.  Each effects measurement is adjusted by several
      m
factors—the argument being that the adjusted dose/response data
better conform to the "real world" situation.  Adjustments include
the following media conversion  (e.g., airborne to waterborne toxi-
cants), safety factors  (e.g., 0.01), various types of exposure
(e.g., workday to full week), and elimination rate (e.g., biologi-
cal half-life).
     The Multimedia Environmental Goals (MEG) chart is the prin-
cipal tool for displaying goals developed with the use of formulae.
The chart was developed at EPA's Industrial Environmental Research
Laboratory (IERL) and has been refined by Research Triangle In-
stitute (RTI) (Cleland and Kingsbury, 1977) with some assistance
from Battelle's Columbus Laboratories.  The chart consists of two
interrelated tables:  (1) a control engineering part including
columns for best technology and minimum acute toxicity effluents
(MATE'S) and  (2)  a health/ecological part including columns for
*LD50:  Lethal dose 50, i.e., the dose of a pollutant required to
        kill 50 percent of a particular animal species by methods
        other than inhalation.
 LDLQ:  Lethal dose low, i.e., the lowest dose of a substance in-
        troduced in one or more portions by any route other than
        inhalation over any period of time and reported to have
        caused death in a particular animal species.
 TLm:   Median tolerance limit value, i.e., the concentration in
        water of a pollutant required to kill 50 percent of a
        particular aquatic species.
                              736

-------
standards/criteria for both human health and ecological systems.
The chart has rows for the three media—air, water, and land.
The MEG chart is considered an indispensible part of the Environ-
mental Assessment programs at IERL.  Any work on the development
of environmental goals needs to be applicable, eventually, to MEG
chart activities.  Applications of currently available values are
presented in the paper by Tolle et al.  (1978, conference proceed-
ings).  In the present section, the thrust of the research is to
expand and improve the quality of the current environmental goals.
     The major strengths and limitations of some 20 formulae cur-
rently in use were identified.  Extrapolation formulae were re-
viewed from three viewpoints:  media, dose/response data, and ad-
justment factors.  This evaluation led to improvements in the
state-of-the-art for estimating biological effects.
     Ten major strengths of the formulae were identified.  Some
of the most powerful were embodied in the formulae used to estimate
permissible concentrations for airborne pollutants.  These formu-
lae use a variety of the most rigorous dose/response data which
include a variety of measurements, e.g., threshold limit values
(TLV's) and other large data sets.  The ability to incorporate
simple adjustment factors is seen as a strength; generally, the
prediction is assumed to improve as more adjustment factors are
incorporated.  Particularly useful adjustment factors are tho,se
for exposure time, elimination rates, and safety factors.
     Seventeen major limitations of the formulae were identified.
Prom the media viewpoint, the formulae for land- or food-borne
                               737

-------
 pollutants exhibit the most limitations; the crop uptake model is



 too simplistic, among other deficiencies.  Many available toxico-



 logical response data, e.g., LDT 's, have not been used in the
                                J_iU


 available formulae.  Responses are limited to a few species of



 animals; few or no responses are provided for plants and micro-



 organisms.  The bulk of the effects data is based on acute or



 short-term exposure when chronic or long-term exposure effects



 data are needed.  The effects data are for single chemicals when



 responses to mixtures of chemicals are needed.  So, from the dose/



 response viewpoint, there are several limitations.  From the ad-



 justment factor viewpoint, there is a need for validation of the



 reasonableness of the factors.   Safety factors need a biological



 basis.   And,  for every limitation in the effects data, there



 should  be an attempt at a compensatory factor.  Thus,  if the



 chronic effects data are available, a chronic adjustment factor



 could help extend the acute effects data.  In summary, there are



 many limitations.



      Research  concentrated  on the reduction/removal of five  of



 the  limitations:  identification of alternative  state-of-the-art



 formulae, correlation of nonoral with or  LD50's, use of  chronic



 effects data,  extrapolation of data from  one  species to  another,



 and development of a biological basis for safety factors.  The



 following material summarizes some  of the major points and recom-



mendations achieved in the  research.
                               738

-------
                      Alternative Formulae
     Other formulae could be incorporated into the present system.
Some formulae handle exposure and biological half-lifes more rig-
orously than any one of the 20 formulae.  Typical state-of-the-
art formulae are those for (1) maximum permissible concentration
for radioisotopes  (International Commission on Radiological Pro-
tection, 1959) and  (2) CUMEX  (cumulative exposure) index  (Walsh
et al., 1977).  Inclusion of the former could provide a more rig-
orous estimation of waterborne radionuclides and related pol-
lutants.  The latter could provide estimates for air and water
separately and simultaneously.  Multiple exposures are the reality
and more formulae, capable of handling such exposures, need to be
developed for future estimations of potential dangers to living
organisms.
               Correlate Nonoral with  Oral  LD50's
     One of  the more  quantitative  formulae  (Handy and Schindler,
 1975)  in use requires that dose/response  data be in  the  form  of
 oral LD50  for rats.   However,  there  are many nonoral toxicologi-
 cal response data which could be used,  if a conversion method
 were available.   To overcome  this  limitation, specially  designed
 equations  were developed by Battelle's Columbus Laboratories  to
 permit conversion of  toxicological data for nonoral  routes of
 administration to the oral route.  Conversions  were  developed for
 intravenous, intraperitoneal, and  subcutaneous  LDso's and inhala-
 tion LC50  to the  oral LD50.   For  example, the  relationship for
 intravenous  LD50  to oral LD50 is:
                               739

-------
     In(oral LD50) = -0.57 + 1.59 In(intravenous LD50)



This research expands the access to other readily available toxi-


cological effects data and is immediately applicable.  This type


of research needs to be extended to better utilize the wealth of


toxicological data for other routes of administration, e.g., LDLQ,


TD   , LCT~, etc., and for other species  (e.g., mice, hamsters and
  LO    LO

dogs).


                 Introduce Chronic Effects Data


     Limitations inherent to biological effects data for short-


term (acute) exposure can be removed only by use of effects data


for long-term  (chronic) exposure.  Chronic exposure  (low levels


of chemicals for long periods of time) can depress reproductive


capacity, increase the number of malignant tumors, and generally


shorten the life span of males, females, or both.  Chronic effects


for life-term  (1000+ days) and multigeneration  (three-generation)


studies for rodents were examined; Table 3 provides such data.


It is assumed that concentrations lower than those used in acute


exposure (high levels of chemicals for short periods of time)


cause effects that could not have been known on the basis of acute


tests only.  Concentrations of 5 ppm for some elements in drink-


ing water seem to show increasingly harmful effects the longer


the study and the greater the number of generations studied.  At


present, there seems to be no quantitative way to predict chronic


effects based on effects data only from acute experiments.   When


chronic effects data are available,  they should be used in the
                               740

-------
  Table 3.  Selected chronic effects on multigenerations
            of rodents of selected pollutants
Element
Control
As
Cd
Ni
Se
Water
Dosage
(ppm)
—
3
10
5
3
Effects
Death and runts rare; bred
for 4 years
Mice survived well thru F3;
tion in litter size
Toxic to breeders by F2» 13
runts
Litter size decreased; few
Strain began to die by F3;
cent runts

normally
reduc-
percent
males in
24 per- .
Source:  Schroeder and Mitchener, 1971.
F2 = second filial generation.
F3 = third filial generation.
                             741

-------
dose/response part of the formulae if the effects are greater than
those indicated by acute exposure data.
      Extrapolation of Response from One Sjaecies to Another
     Animal toxicity data can be extrapolated from one species to
another in at least two ways.  In one approach, the equation deals
with only one toxicant at a time, but this single equation can be
used to predict the responses of animals of many sizes  (including
man) to that particular toxicant.  In another approach, the equa-
tion deals with responses to many different toxicants, but it can
only be used to extrapolate from the response of one particular
species to the response of another species  (say, from rat to hu-
man) .  Both methods are related to the basic relationship of Y -
aWb  (Kleiber, 1947; Anderson and Weber, 1975) where Y = the re-
sponse, W = body weight  (or area), and a and b  are constants rela-
tive to the particular Y.  Unfortunately, the basic data are not
readily available.  Continued work in extrapolation of one species
to another, especially man, is of such paramount importance.
               Biological Bases for Safiety Factors
     The range of sensitivity for certain organisms to given toxi-
cants provides a biological basis for safety factors.  Toxic levels
and effects of a substance vary greatly.  For example, toxicity
ratios for young of a species versus adults can vary from 0.002
to 16—a variation  of nearly  four orders  of magnitude (Casarett
and Doull,  1975).  Green algae species differ in their response
to cadmium by a factor of 100 (Buehler and Hirshfield, 1974).
Frog embryos and larvae are more sensitive than adults to
                              742

-------
mercury by factors of 100 and 1000, respectively (Porter and Hakan-
son, 1976}.  Bird embryos and fetal and newborn mammals are more
susceptible to metals than their adult counterparts  (National Re-
search Council, 1976).  Baby mammals appear to be four to five
times more sensitive than adults to some chemicals  (Goldenthal,
1971).  In aquatic situations, safety factors of 100 and 1000 seem
reasonable if effects data are available from the most resistant
species; if test data are for the most sensitive species, such
high safety factors are unwarranted.  In terrestrial situations,
smaller safety factors seem biologically reasonable.  For example,
10 to 100 would be reasonable when the available dose/response
data are for resistant species.
     All of these improvements still fall short of the needed ad-
vancements in this important research to protect human health and
the environment from adverse effects.  True, the formulae provide
quantitative values and increasingly higher quality effects data
and adjustment factors are being used in such formulae.  The state-
of-the-art predictions are not absolute; they are relative.  Fur-
thermore, the relative relationships of one prediction to another
may not be correct.  Caution is warranted.  Validation and future
monitoring are needed to confirm the reliability ,of the predic-
tions.  Another major step forward involves the issue of mixtures
as compared to single chemical species.  The approach of predicting
permissible concentrations for single chemical species will need
to be replaced by approaches addressing synergistic/antagonistic
effects associated with the release and dispersion of actual
                              743

-------
 emission streams.   Then,  establishing environmental goals and feed-
 back to control technology development will be based,  increasingly,
 on sound,  complete,  rigorous effects data.
                     Pollutant Prioritization
      It is not difficult  to generate a list containing 100 or
 more possible or potential pollutants which can result from coal
 cleaning;  if coal  utilization is included,  the list can increase
 several-fold.   Obviously,  these are not all of equal importance.
 Thus,  one  of the goals  of  the coal  cleaning environmental  assess-
 ment program is to establish decision criteria to  determine the
 relative priorities  to  be  assigned  to controlling  specific pol-
 lutants.
     As indicated  in Figure  1  (see  page  3)  all  of  the  environ-
mental assessment  subtasks shown provide input  for  a prioritiza-
tion.  Also, as  noted earlier,  a fundamental criterion for  rank-
ing  the importance of any pollutant  is the  relationship between
its  expected environmental concentration and the maximum concen-
tration which presents no hazard to man or  biota on a  continuous,
long-term basis.  The estimated environmental concentrations  (EEC)
of pollutants can be projected on the basis of coal feedstock,
process configuration, control devices applied/ environmental
dilution and dispersion, etc.
     The other half of the relationship, the estimated permissible
concentration  (EPC),  is quite another matter.  As indicated above,
the toxicological and epidemiological data needed to characterize
the relative health and ecological risks of the pollutants to be
                                744

-------
expected from coal cleaning processes are woefully inadequate.
 (The information base  is in far better shape for many of the
chemical compounds encountered in the chemical and similar indus-
tries, but almost none of these are of any concern to coal clean-
ing.)  Additionally, the exact chemical form of many coal clean-
ing pollutants is unknown more often than not.  There appears
very little likelihood that the EPC data base for coal cleaning
pollutants will improve dramatically in the near future.
     Thus, in spite of its undeniable theorectical soundness and
anticipated ultimate success, the EEC/EPC relationships will prob-
ably be unable to provide substantial prioritization guidance
over the near term.
     Looking toward the longer term, another of the U.S. EPA's
contractors, the Research Triangle Institute, is developing the
concept of multimedia  environmental goals  (MEG's) of which health-
related and ecology-related estimated permissible concentrations
of air, water, and land are key parameters.  Current status of
this ongoing effort has been described by Cleland and Kingsbury
(1977).  Because of the data insufficiencies mentioned above, the
MEG tabulations for pollutants from coal cleaning processes are
incomplete, which limits their present application.
     Another approach to the estimation of acceptable concen-
trations utilizes Minimum Acute Toxicity Effluents (MATE's).
These are considered to represent the very approximate concentra-
tions of pollutants in air, water, and land effluents, below
which only minimal harmful responses are evoked by short-term
                              745

-------
 exposure.  As reported by Cleland and Kingsbury  (1977), six MATE
 concentrations may be described for a single compound with two
 MATE'S based on health and ecology for each medium.  While there
 are also large gaps in the toxicological data needed to estimate
 MATE'S, the types of data from which MATE'S can be derived are
 also of the short-term,  acute category and are thus more amen-
 able to empirical treatment.
      Source Analysis Models (SAM'S)  have been developed by Acurex,
 another of U.S.  EPA's contractors, to assist in comparing elements
 of an environmental assessment.   The simplest SAM, designated
 SAM/IA, is designed for  rapid screening of effluent streams and
 assumes no effluent transformation.   As described by Schalit and
 Wolfe (1978),  rapid screening of the degree of hazard and the rate
 of discharge of  toxic pollutants may occur at any level of depth
 of chemical and  physical analysis.  In SAM/IA,  effluent concen-
 trations are compared to the  appropriate MATE's;  the comparison
 may also evaluate the difference between an uncontrolled process
 and one with pollution controls.
      In the long  run,  a  rigorous  approach to  the  ranking of  rela-
 tive  importance of  pollutants will probably be  possible.   However,
 for the  near term,  utilizing the assumption that  the  relative  im-
 portance of a pollutant can be based generally  on  its toxicity  and
 its abundance and that those substances  for which  criteria have
 been established or which have been designated  as  pollutants are
 important.  The preliminary "Priority 1"  list of 74 pollutants
mentioned earlier had its origin in these considerations.  The
                              746

-------
 relative  importance of  the  13  elements  included  in the  "List of
 65  Toxic  Pollutants," recently published  by  EPA  (43 FR  4108,
 January 31,  1978), has  undoubtedly  increased as  a result of that
 listing.
      Preliminary working prioritization lists can be derived by
 comparing the  emission  concentrations  (uncontrolled and controlled)
 in  each stream (air or  water)  with  the  concentrations established
 by  air or water quality criteria or by  regulation.  These  concen-
 tration levels may be health-  or ecology-based,  or both; or they
 may reflect  available technology, e.g., "best available control
 technology"  (BACT).  Such lists will provide a working  basis for
 prioritization of R & D efforts while the more precise  and so-
 phisticated  MATE'S and  MEG's are being  perfected.  This is the
 direction of the current studies, and it  is  planned to  develop a
 provisional  pollutant rating within the next 6 months.  This first
 generation prioritization will necessarily be based on  less-than-
 rigorous  criteria, including,  where insufficient information is
available, estimations based on scientific judgments.   As more
information is developed,  refined lists will be generated.
                               747

-------
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                               751

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                              752

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      APPLICATION OF ENVIRONMENTAL ASSESSMENT METHODOLOGY TO HOMER CITY
         POWER COMPLEX BACKGROUND DATA:  COMPARISON WITH MEG VALUES

                D. A. Tolle,  D.  P.  Brown,  R.  Clark, D.  Sharp,
                       J.  M.  Stllwell,  and B. W.  Vigon
                      Battelle's Columbus  Laboratories
                               Columbus, Ohio
                                  ABSTRACT
     During the period from December 1976 through April 1977,  a series  of multi-
media, grab-sampling campaigns were conducted by Battelle's Columbus  Laboratories
at the Homer City Generating Station near Homer City,  Pennsylvania.   The intent
of this pre-operational monitoring was to document the abundance or concen-
trations of selected key parameters in order to evaluate the air, water, and
biological quality in the vicinity of an advanced coal cleaning plant.   These
environmental studies, while not sufficiently long term to be a true  baseline
analysis, were conducted prior to operation of the cleaning plant as  a  reference
point for future, and more comprehensive, environmental testing planned during
operation of the plant.

     The multimedia studies involved sampling, laboratory analysis, and eval-
uation of the following components of the environment  In and around  the Homer
City Generating Station.

     •  Fugitive dust monitoring using high-volume samplers

     •  Water and stream sediment quality monitoring from grab samples

     •  Aquatic biota sampling of attached algae, bottom-dwelling
        invertebrates, and fish in streams

     •  Terrestrial biota reconnaissance of wildlife and vegetation
        within a two-mile radius

     •  Cleaning plant refuse disposal facility evaluation.

     The objective of this paper is to present some of the fugitive  dust,
water, and sediment sample analysis data from the studies at Homer City and
compare this data with the values listed in  the Multimedia Environmental Goals
(MEG) document prepared for the U.S. EPA by  Research Triangle Institute.  The
MEG values considered in this paper are the  maximum levels of significant
contaminants that are Judged to be appropriate for preventing certain negative
effects in the surrounding populations or ecosystems.  The MEG methodology
                                      753

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 was developed to meet the need for a workable system of evaluating and ranking
 pollutants for the purpose of environmental assessment.  The values considered
 in this paper include the following.

      •  Minimum Actue Toxicity Effluents (MATE's) - concentrations of
         pollutants in undiluted emission streams that are acceptable
         for short-term exposure.

      •  Estimated Permissible Concentrations (EPC's) - the maximum
         concentration of a pollutant which presents no hazard to man
         or biota on a continuous long-term basis.

      The utility of the MEG approach to environmental assessment is explored
 in relation to the Homer City data.


                            INTRODUCTION
      Battelle's Columbus Laboratories  has  contracted with  the

U.S.  Environmental  Protection Agency  (U.S.  EPA)  to perform a com-

prehensive environmental assessment of physical and chemical coal

cleaning processes.   The broad goal of this program (Contract No.

68-02-2163)  is to establish a strong base  of engineering,  ecologi-

cal,  pollution control,  and cost data  which-can be used to deter-

mine  those coal cleaning processes that are most acceptable from

the technological,  environmental, and  economic viewpoints.   The

data  base also will be used for pollution  control trade-off

studies  that will compare the various  individual and combination

techniques for reduction of the pollution  potential of coal-fired

power plants.   In addition, these data  will be used to identify

any areas where development of pollution control equipment  may be

needed.

      Since one of the program goals involves  an  analysis of

methods  for  reducing overall environmental  pollution through the

use of cleaned coal, mathematical and modeling techniques will be

used  for identification  of  optimum coal cleaning process
                                 754

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 configurations, pollution control equipment, and waste management
 techniques.  These optimization studies will require an assessment
 of the pollution potential of coal cleaning processes, associated
 facilities, and—in certain cases—the end uses of coal.
      In order to obtain the field data necessary for the overall
 program,  Battelle is undertaking a sampling and analysis program
 designed  to identify the combinations of coal cleaning processes
 and environmental conditions which are most effective in reducing
 the total impact of coal use on the environment.   This will be
 accomplished through the characterization of process and effluent
 streams from a  variety of coal cleaning facilities  and their
 associated coal transportation,  storage,  and refuse disposal areas.

                     Objectives of  Homer City
                    Pre-Operational Monitoring

      The  recent construction of  an advanced coal cleaning  facility
 at  the  Homer City Power  Complex  near  Homer  City, Pennsylvania,
 provided  a unique opportunity  to obtain environmental data  both
 before  and after operation of  the plant.  Thus, in  order to docu-
 ment  the  abundance or  concentrations  of selected key parameters
 Battelle  conducted a series of pre-operational, multimedia,  grab-
 sampling  campaigns in  a  study area that included this facility.
 These data were used to  evaluate the  air, water, and biological
 quality in the study area.  The pre-operational environmental
 studies, while not sufficiently long-term to constitute a true
baseline analysis, were conducted prior to operation of the
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cleaning plant as a reference point for future, more comprehen-
sive, environmental testing planned during operation of the plant.

               Specific Objectives of This Paper

     The objective of this paper is to present some of the pre-
operational monitoring data from Battalia's study area near Homer
City, Pennsylvania, and to compare these data with the values
listed in the Multimedia Environmental Goals  (MEG) documents pre-
pared for the U.S. EPA by Research Triangle Institute  (Cleland
and Kingsbury, 1977a and b).  The MEG values considered in this
paper represent the maximum levels of significant contaminants
which are not considered to be hazardous to man or the environment.
The MEG methodology was developed to facilitate the evaluation and
ranking of pollutants for the purpose of environmental assessment
of energy-related processes.
     MEG values have been estimated for 216 pollutants by  extrapo-
lating various toxicity data by means of simple models.  For most
of these pollutants, maximum values have been estimated for each
of the three media  (air, water, and land).  For each  of the three
media/ separate maximum values have been estimated which are not
considered to be  hazardous to  (1) human health and  (2) entire  eco-
systems.
     The MEG values  that are particularly  appropriate for  compari-
son  with the environmental monitoring  data from Battelle's study
area are those designated  as estimated permissible  concentrations
 (EPC's).   EPC's  are  the maximum concentration of  a  pollutant
                                756

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 which presents no hazard to man or biota on a continuous long-term
 basis.  These EPC values are considered acceptable in the ambient
 air, water, or soil, and do not apply to undiluted effluent
 streams.  The ambient application of EPC's corresponds to the ambi-
 ent type of sampling conducted by Battelle prior to operation of
 the Homer City Coal Cleaning Plant.
      A second type of MEG values considered in this paper is one
 comprised of minimum acute toxicity effluent (MATE)  values.
 MATE'S are concentrations of pollutants in undiluted effluent
 streams which will not adversely affect those persons or ecologi-
 cal systems exposed for short time periods.   Very little of  the
 pre-operational  monitoring conducted by Battelle near Homer  City
 involved undiluted effluents,  but in the case of a few pollutants,
 this value was the only MEG value determined.

                  Description of  the Study Area

      Nearly all  of Battelle'a  environmental monitoring was con-
 ducted  within  a  study  area  that  can be  approximately bounded by a
 circle  4 miles (6.4  km)  in  diameter.  The  advanced coal cleaning
 plant in the center  of  the  study area is  about 2  miles (3.2  km)
 southwest  of Homer City, Pennsylvania.  Only two  of  the aquatic
 biota sampling stations were slightly outside of  the  circular
 study area.
     The six major habitat  types within the study area  are hard-
wood forest, coniferous forest,  cropland, grassland, water bodies,
and areas of industrial development.  The forested areas are
                               757

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primarily hardwoods, dominated by oak and hickory.   Isolated



pockets  of pine  are present as plantations  rather than  naturally



occurring species.  Cropland  is extensive in the study  area, in-



cluding  contour  and strip-cropped fields of corn, wheat, and hay.



Grasslands include those areas that are presently grazed and



those areas that were previously grazed or  farmed and are now in



a transition stage toward becoming a forest.



     Stream water quality evaluated within the study area is



affected by a number of land  uses which are either included in the



immediate study area or take  place at locations farther upstream.



The five major land uses affecting stream water are:  agriculture,



mining,  urban, construction,  and power generation.  Agricultural



runoff is a problem because of the hilly terrain and includes run-



off from both farmland and pastures.  Almost the entire study



area is on top of deep mines, while much of the upstream water-



sheds add acid mine drainage  from abandoned or active strip mines.



As indicated earlier, Homer City/ Pennsylvania, is immediately



adjacent to the study area on the northeast, and Indiana, Pennsyl-



vania is only 5 miles (8.0 km) north of Homer City.  Both towns



directly or indirectly add effluents from industrial and sewage



treatment facilities to Two Lick Creek before it flows through



the study area.  During Battelle's sampling campaigns, both the



coal cleaning plant and the refuse disposal area for that facility



were under construction in the study area.  Finally, the study



area includes the Homer City Power Station,  with its associated



coal storage,  water treatment, and waste disposal facilities.
                               758

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     The Homer City Station is one part of an integrated power



complex which includes two deep coal mines; coal cleaning, stor-



age, and transport facilities; power generation facilities; and



waste disposal and treatment facilities (Figure 1}.  Coal used at



the Homer City Station comes from the two dedicated deep mines in



the power complex, as well as that hauled by truck from other



mines.  Solid refuse from power complex activities is deposited



in three different types of disposal areas, including an ash dis-



posal area, mine waste or "boney" piles, and the cleaning plant



refuse disposal area.  Liquid waste treatment facilities in the



power complex include:  mine and boney pile leachate water treat-



ment facilities, an emergency holding pond constructed near the



coal cleaning plant, coal storage pile runoff desilting ponds, an



industrial waste treatment plant, power plant storm runoff desilt-



ing ponds, bottom ash sluice water desilting ponds, sewage treat-



ment facilities, and ash disposal area leachate treatment ponds.







                 SAMPLING AND ANALYSIS TECHNIQUES





     During the period from December 1976 through April 1977, a



series of three pre-operational, grab-sampling campaigns were con-



ducted by Battelle in the ambient media of the study area which



included the Homer City Power Complex.  These environmental moni-



toring studies involved sampling, laboratory analysis, and/or



evaluation of the following components of the environment.



     •  Fugitive dust



     •  Stream water and sediments





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A - Aih Diipoul Area
B — Mine Drainage Treatment Pond
C - Helvetia Boney Pile
O — Coal Cleaning Plant
E - Coal Storage Pita
F - Power Plant
G - Induitrial Wait* Treatment Plant
H - Helen Boney Pill
    Figure  1.    Map  of  the  Homer  City Power  Complex
                                      760

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     •  Aquatic biota
     •  Terrestrial biota
     •  Raw coal and fly ash
     •  Cleaning plant refuse disposal area
     •  Groundwater.
Only the first three were analyzed in sufficient detail to warrant
comparison with MEG values.  Samples of fugitive dust, water, and
stream sediments were collected during three campaigns and
analyzed for physical and chemical parameters.  Aquatic biota were
sampled during two campaigns for determination of indicator spe-
cies, standing crop, species diversity, and chemical analysis of
fish.

                          Fugitive Dust

     Fugitive dust monitoring was conducted using high-volume  (hi-
vol) ambient air samplers during the following three 48-hour sam-
pling periods:
     •  Campaign I:    8 p.m. December 17 to 8 p.m. December 19, 1976
     •  Campaign II:   8 p.m. January 5 to 8 p.m. January 7, 1977
     •  Campaign III:  8 p.m. April 5 to 8 p.m. April 7, 1977.
The first of these three campaigns was conducted over a weekend
when both coal transfer and construction activities were low.
     A multiple-source . fugitive-dust   dispersion model was used to
select and verify locations for hi-vol samplers  (Figure 2).  This
model takes into account such factors as wind speed, emission
rate, particle size, and distance from selected potential dust
                                761

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                                                 Coal Cleaning
                                                 Refuse Disposal
 Existing Ash
 Disposal Area
Coal Cleaning Plant
                                      Coal Storage Pile

                                                  Substation
                                            (1)
                                            Power Plant
                                                 Cooling Towers
   Wind Speed and Direction
   Recorder
5 ) Hi Vol. Sampler
    Figure  2.   Location  of  fugitive  dust sources  and

    monitoring sites.
                               762

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sources located within the Homer City Power Complex.  No dust



sources outside of the power complex were incorporated in the



model.  On the basis of the computer-generated diffusion-modeling



results, ten monitoring sites were established at distances of



175 to 2200 m downwind from various local dust sources.  One of



the ten sites was on private property downwind of the power com-



plex, while another was on private property upwind of the complex.



     Several potential dust sources, both local and regional,



were not incorporated into the diffusion model for sampling site



selection.  Dust generated by vehicular traffic, parking lots,



construction activities, several storage silos, and especially



that originating from the surface of the plant grounds were not



included in the model because of their erratic and nonpoint-



source nature.  Data for the Homer City Power Plant stack emis-



sions were not available in time to include them in the model.



In addition, four other major power stations  (Keystone, Conemaugh,



Seward, and Shawville) are located in the same Chestnut Ridge sec-



tor of the Allegheny Mountains as Homer City.  These utilities



are fed from coal mines located either directly under or near the



station sites.  The model did not include fugitive emission data



from any of these facilities.



     Potential fugitive dust sources at the Homer City Power Com-



plex were investigated during a pre-sampling  site evaluation.



Some of the dust sources included an ash disposal area, boney



piles at both deep mines, a coal storage pile, road dust, three



power plant stacks, and construction-generated dust.  The coal
                               763

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cleaning plant with its thermal dryers and the cleaning plant



refuse disposal area were under construction during Battelle's



sampling campaigns.  Since these two areas were considered to be



future potential sources of fugitive dust, they were considered



in the selection of sampling sites.



     In order to identify the type and quantity of pollutants



being emitted from fugitive dust sources, a variety of analytical



techniques were employed.  Particulate mass was determined by



weighing the 8 x 10-inch fiberglass filters used in the hi-vol



samplers before and after each of the 12- or 24-hour sampling per-



iods.  A microscopic analysis was made of particulates to provide



a distinction between components such as coal dust, fly ash,



pollen, or construction dust.  An Andersen sampling head was used



on one hi-vol sampler to obtain data on the distribution of par-



ticles in five size fractions.



     Particulates on the filters from the hi-vol samplers were



analyzed for up to 22 elements.  The analytical technique used for



most elements was atomic absorption, but neutron activation, col-



orimetry, a specific ion meter, a total organic carbon analyzer,



an LDC mercury monitor, and potentiometric titration were also



used.  Since large amounts of four of these 22 elements (Na, K,



Ca, and Mg)  were found in the blank filters, the values for these



four elements were not reported.  Four of•the remaining 18 ele-



ments (Sb,  Ti,  V,  Se)  were analyzed only in the second or third



campaign.  in general,  the filter exhibiting the highest
                               764

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 percentage of coal or ash from each site was used for analysis.
 Data for 15 of the elements are compared in this paper.

                    Stream Water and Sediments

      A wide variety of water and sediment quality parameters were
 selected for analysis in the streams and tributaries in the study
 area (Figure 3).   The selection of water and sediment quality
 parameters was based on the diversity of land use in the general
 area,  including farming, mining,  urban,  construction, and power
 generation activities.   The analytical techniques for water and
 sediment samples  were numerous and involved the techniques
 suggested in the  following seven  references:   American Society of
 Agronomy and ASTM (1965),  Hem (1970),  Stumm (1970),  Stumm and Lee
 (I960),  Stumm and Morgan (1970),  U.S.  Department of  the Interior
 (1974),  and U.S.  Environmental Protection Agency (1969).   in this
 paper,  analytical results  for 30  water quality and 9 sediment
 quality  parameters  are  used  for comparison with MEG  values.
     The sampling locations  for surface  water  and stream  sediments
 were selected  in  advance of  field monitoring  (Figures  4 and  5).
 The order of  sampling was  always  from  downstream to  upstream.   All
 sites within a given watershed were  sampled on  the same day  or  on
 two consecutive days.
     All samples were collected in prewashed polyethylene bottles
or glass jars by one of  the two following methods:   (1) grab sam-
pling,  and  (2) use of an automatic sampler.  Grab sampling con-
sisted of submerging each container while keeping it as close to
                               765

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Figure 3.   Streams and tributaries surveyed  in the
Homer City area.
                        766

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Figure 4.  Surface water quality sampling  locations,
                         767

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Figure 5.  Stream sediment sampling locations.
                     768

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 the  surface  as  possible  to  prevent  disturbing  the  bottom  sediment.
 The  automatic composite  sampler  (Instrumentation Specialties  Com-
 pany,  Model  1580)  was  used  at  two sites  where  the  water quality
 was  more  variable.
     Additional data were recorded  at  each site while  collecting
 the  sample.  A  Yellow  Springs  Instrument Company polarographic
 D.O. meter was  used to measure the  dissolved oxygen  content and
 temperature, while a Beckman Solu-Bridge was used  for  specific
 conductance  determinations.  Current measurements  were taken  with
 a  Price-type current meter  (Pygmy meter).   Flow was  estimated us-
 ing  the velocity-area  method.
     Sediment samples  were obtained from several streambeds.
 Sediment  was defined as  any material that  would pass through  a
 10-mesh screen.  There was difficulty  in obtaining an  adequate
 sample at some  sites where the streambed was composed  largely of
 gravel.

                          Aquatic Biota

     Fourteen aquatic  biota sampling sites were selected  in seven
 streams in the  study area, as well as  in an additional control
 stream, Ramsey  Run, which is about 6 miles  (9.6 km) north-northeast
of the study area and  about 1 mile  (1.6  km) east of Indiana,  Penn-
sylvania  (Figure 6).    Sites were chosen which would provide the
best data for evaluating the impact of the existing facilities in
the complex on  the aquatic biota of the  receiving  streams.  Sam-
pling was conducted both upstream and downstream from  potential
                               769

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                                          Kilometer
                                       0     0.5   1.0
                                0       1/2
                                        Mile
                                   Ramsey Run
Figure 6.  Aquatic biota sampling locations,
                       770

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sources of pollution.  Thus, the prior effect of upstream sources
of pollution on aquatic biota was included in the assessment of
the study area.  Only a minimal sampling effort was carried out
in Two Lick Creek because a survey by Environmental Sciences, Inc.,
{1972} reported that this stream had poor water and aquatic biota
quality due primarily to acid mine drainage from abandoned strip-
mines located upstream.
     Three groups of aquatic organisms were selected for study:
(1) periphyton  (attached algae, especially diatoms), (2) benthic
macroinvertebrates  (bottom-dwelling invertebrates visible to the
naked eye), and  (3)  fish.  These three groups of organisms were
chosen because of their relative ease of collection, usefulness
as water quality indicators, and importance in aquatic  food webs.
     Attached algae  were sampled in triplicate by  scraping cobble-
size rocks  from the  stream bottom.  The preserved  diatoms were
prepared for viewing on a microscope  slide and identified to spe-
cies.  Standing crop was expressed for each species  in  terms of
number of organisms/cm2.  Finally, total periphyton  standing crop
and total number of  species  identified were calculated  for each
sampling  site.
      Bottom-dwelling macroinvertebrates were  collected  from  riffle
areas using a  Surbur sampler.   Five replicate samples were taken
at all stations  and were preserved with  formalin and returned  to
Battelle  for  sorting,  identification,  and  enumeration.   All  organ-
isms  were identified to  the lowest  practical  taxon,  and the
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resulting data were used to calculate species diversities accord-
ing to the Shannon-Weaver formula (Shannon and Weaver, 1963).
     Fish were collected by using a 4 x 6-ft, 1/4-in-mesh seine
and/or a backpack shocker.  Both devices were used during the
spring survey, but only the seine was used during the winter sur-
vey.  Fishing was conducted with approximately equal effort
(1/2 hour) at each station.  Fish were identified, recorded, and
released.  Specimens not positively identified in the field were
placed in sample bottles, preserved, and returned to the labora-
tory for identification.
     Biological quality was determined for each of eight portions
of streams or tributaries surveyed in the study area.  Quality of
the biota in the control stream  (Ramsey Run) was evaluated as good
and provided a basis for comparing the other streams.  The subjec-
tive evaluation of aquatic biota quality in each stream was deter-
mined by initially evaluating each of the three groups of organ-
isms surveyed.  The evaluations were based on the presence of indi-
cator species, standing crop of diatoms, species diversity of
bottom-dwelling macroinvertebrates, and number of individuals per
fish species.  Finally, overall biological quality ratings of
good, fair, or poor were based on the individual ratings for the
three aquatic biota groups.

          COMPARISON OF ANALYTICAL DATA WITH MEG VALUES •

     Analytical data for fugitive dust, fly ash, raw coal, surface
water, and stream sediments sampled in the study area have been
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converted to the units used in the multimedia environmental goals
(MEG) study (Cleland and Kingsbury, 1977a and b).  These data are
compared with the estimated permissible concentrations (EPC's}
and/or the minimum acute toxicity effluent (MATE) values defined
in the Introduction to this paper.  In addition, the observed and
recommended values for stream water and sediments are compared
with the biological quality evaluations made at sampling locations
in the same portion of a given stream.

                     Fugitive Dust Analysis

     Average concentrations of 15 elements analyzed in the fugi-
tive dust from the study area are compared with the EPC's for air in
Table 1.  Since most of the fugitive dust appeared to emanate from
the coal storage pile and decline in concentration within 200 to
300 m downwind (Figure 7), the data have been averaged for the
sampling sites located between 150 to 175 m and 400 to 1,800 m
downwind from the coal pile.  The fugitive dust concentrations fo]
the upwind "control" sampling location are also provided.  These
field data are followed by the appropriate maximum EPC's for air
which are recommended for each element to prevent negative effects
to humans or the surrounding environment during continuous long-
term (chronic) exposure.  A difficulty in making comparisons be-
tween observed and recommended levels of the 15 elements shown in
Table 1 is that three EPC's for human health and 10 EPC's for the
environment are not available.
     Average concentrations for three of the elements  (As, Cr, and
Pb) analyzed in fugitive dust exceeded the EPC's for human health.
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Table  1.    Fugitive  dust  comparisons
                versus  Homer City data
                                                                                  )s    EPC  values  for air
Trace Eleneat Concentration*, ug/m

Distance from
Coal Pile
Downwind 150-175 n^
Dowwind 400-1.800 »(c)
Unwind Control'**
EPC Category
Health
Ecology
As Cd
Average
Cr Cu
Concentration in
0.014 0.008 .026 0.292
0.010 0.014 .015 0.119
0.009 0.005 .014 0.223

0.005 0.12
— 0.04

0.0020.5
 _ _
Fe
Pb
Fugitive Dust
Mn
During 3
3.45 0.586 0.076
1.87 0.334 0.093
1.6S 0.258 0.041
Estimated Feradsaible
—
* 0.36
!<«>
12
HR
Canmaigns
Hi n
Zn a F T Se
•t Boner City (24-hr Sanpllng Periods) M
O.OOOM 0.015 O.U
0.00009 0.013 0.32
0.00003 0.009 0.17(i)
Concentrations (EPC's)(c).
»-
0.04«>14
0.35*4) 1.97W) 5.47 TO^' 0.0049
0.22 0.82 2.03 HD 0.0026(1>
0.13 1.05 1.40 0.02(1) O.W»(i*
W/n3
9
.5 — — 1.2 0.5
(a)  All (Uta uere collected between December 1976 and April 1977.
O>)  Average for saapllng aites 1 and 3; dovmrlnd of coal pile.
(c)  Average for saspllng sites 4. 8, and 9; doumrlnd of coal pile.
(d)  Sampling site 6; upwind of coal pile about 1600 • and off of the power stitloo property.
(e)  From Cleland and Klngabury (1977).
(f)  Based oo a Toxic Unilt Value (TLT) vhich recognlsea the eleneat's carclno-cenic potential
(g)  Based on teratogenlc potential.
(h)  H>t available.
(1)  Concentrations vere not available for some sanpling sites daring all three campaigns.
(J)  •> - not detectable.

-------
- 1300
-2 I2OO
o
            Park
                7
                                                                 Future
                                                                 Coal Refuse
                                                                 Site
                        500                1000
                               Meters From Coal Storage Pile
1500
          Figure  7.   Fugitive dust concentrations compared to a  transect
          of the  area's topographical relief.
                                                                                  300


                                                                                  250

                                                                                     t
                                                                                  200o.


                                                                                  ISO.g.


                                                                                  100 £


                                                                                  50 **
2000

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 These values have been underlined in Table 1.   It is noteworthy
 that two of these elements (As and Cr)  had concentrations above
 the health-based EPC,  even at the upwind "control" location.
      Maximum and minimum concentrations of 15  elements analyzed
 in  fugitive dust are  compared with the  appropriate EPC's  for  soil
 in  Table 2.   Again, the data  are grouped to include sampling  sites
 located  less than 200  m (i.e.,  150 to 175 m) and  greater  than 200 m
 (i.e., 400  to 1,800 m)  downwind of the  coal pile.   Concentrations
 of  the same elements  in the raw coal are also  shown.   EPC's for
 protection  of human health and the environment are given  for  12
 elements; no EPC values for iron,  chlorine,  and fluorine  have
 been determined.
      The majority of  the elements  analyzed showed  maximum, and fre-
 quently  minimum,  concentrations in the  fugitive dust which were
 far greater  than  the EPC levels suggested for  the  soil.   Ten  ele-
 ments exceeded the EPC's for  human health and  11 elements exceeded
 the EPC's for the environment.   Both the maximum and  minimum  con-
 centrations  of 8  elements  (As,  Cd,  Cr,  Cu,  Pb,  Mn,  Ni,  and Se)  in
 the fugitive  dust exceeded  the  EPC's for both  human health and the
 environment.
      Obviously, the detected  concentrations of  toxic  trace ele-
ments in fugitive  coal  dust that has  settled to the ground sur-
 face  do not  indicate that these same  concentrations occur in  the
 soil.  However, studies  involving  soil  contamination  by other
 types of particulate deposition have  shown that toxic trace ele-
ments in these partioulates can cause ecosystem disruption
                               776

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           Table  2.    Fugitive  dust  comparisons   (yg/g):    EPC values  for  soil
                           versus  Homer City data



Maximum
Minimum

As Cd Cr

154 26« 471
11 18 18

Cu
Concent rat Ions
3,678 28
336 6

Fe
Trace den
Pb
in Psrticulate at
.736
.223
Concentrations in Participate at
Haximua
Minimum
238 619 667
3«_ ND 46
6.061 57
220 11
.576
.477
17,241
501
ent Concentration, ui/g
Ha Hg
Sampling Sites
632 3
65 0.2
Ni
Tl
within 200 • of
264
23
Sampling Sites Between 200 and 2 000
12.857
566
5.603 2
6 ND
545
H>
Estimated Permissible Concentrations
Health
Ecology

Kaxicua
Minimum
10 0.06
1 a(d)
10 50(C>
i 1H)
Concentrations Determined by Individual Analysis
.31 48
20 18
.750
.000
17.3
H
2* 1.1
35 0.34
0.1 ) for Soil
1,000
i
27,278 45.600
S.806 1,818
00
-» ->>
-.<«) _<«>
V
3)(.)
ND
ND
«J 9)ta)
ND
m

1.4
12-
Se

33
4.

122.
1

2
SLJL<«
Homer City Coal Sources ***
1,329
1.125
66
46
0.26 108
0.23 91
65
»
ND
ND
(a)  Data from three sampling campaigns conducted by tattelle In the study area.
(b)  From Cleland and Klngsbury (1977): all values «ere multiplied by 100 based om perseaal commuilcacloa with ttngsbury (August. 1978).
(c)  Baied on carcinogenic potential.
(d)  Based on teratogenlc potential.
(e)  Value noc available.
(f)  KD - not detectable.
(C)  Coal sources Include:  Helen Mining Company and Helvetia Coal Company (from Upper rreemo.t Sean); and Trucked-ln Coal (from Lower Mttannin* Sean).

-------
resulting in the loss of essential nutrients and can also result



in increased concentrations of these toxic elements in both plants



and animals.  These types of effects have been demonstrated for



lead smelter emissions  (Jackson and Watson, 1977; Kerin, 1975) and



for fly ash emissions from coal-fired power plants  (Furr et al.,



1977).  Dvorak et al. (1978) have speculated that long-term expo-



sure to uncombusted coal dust may cause changes in vegetation com-



munity structure similar to those caused by particulates from coal



combustion.



     Mechanisms for the movement of toxic trace elements from par-



ticulate emissions deposited on the ground to the root zone of the



soil are complex (Vaughan et al., 1975; Dvorak et al., 1978).  A



partial list of the factors that influence leaching of trace ele-



ments from deposited particulates into the soil solution include:



(1) the size and type of particulates, (2) the amount and acidity



of precipitation,  (3) the concentrations and physicochemical pro-



perties of the trace elements,  (4) the texture, organic content,



pH, and other characteristics of the soil, (5) the  solubility of



elements into the  soil  solution, and  (6)  the temperature of the



air and soil.



     The fugitive dust  quantity and composition found during moni-



toring has probably been accumulating on the ground in a reason-



ably similar fashion since the power plant (including the coal



storage pile) began operation in 1969.  Thus, mobile elements in



the settled dust may have leached into the soil.  The quantity of



toxic trace elements available to vegetation, however, needs to
                               778

-------
be determined by chemical analysis of the soil.  In spite of any
leaching of trace elements which may have increased soil concen-
trations, vegetation growing within a broad band around the coal pile
has not yet experienced any apparent adverse effects.  An analysis
of soil biota and plant diversity, however, was not conducted.

           Stream Water, Sediments, and Biota Analysis

Stream Water Concentrations Versus MEG Values

     Maximum and minimum concentrations of 15 elements that were
analyzed in surface water are compared with the appropriate MATE
and EPC values for the environment in Table 3.  These data were
organized to correspond to the biological sampling locations for
additional comparisons.  Although data were obtained in the study
area near Homer City for 30 different parameters used to define
water quality in stream water, MEG values are only available for
the parameters listed in Table 3.
     EPC and MATE values suggested for the environment were
exceeded by many of the maximum and minimum values determined for
the 15 water quality parameters listed in Table 3.  Maximum values
for nine parameters measured in surface water throughout the study
area exceeded the corresponding MATE values, and maximum values
for 11 parameters exceeded the corresponding EPC values.  Maximum
and minimum values of measured parameters exceeded EPC's in the
following 10 cases:  beryllium, lead, ammonia, nitrogen, arsenic,
manganese,  nickel, copper, zinc, and cadmium.
                               779

-------
Table 3.  Surface water quality comparisons (yg/1):

                         (a)
          Homer City data
MEG values versus
Stnan in the Tlclnltr of ROOT City Station


KK Category
and Subctun.
IB Phenolic*
31 taryllloB
34 Calcine?
46 Uad
47 Amoala
S MtrC|"
O *' Arienlc
63 vanadliai
68 Chrralixi
~4£
68 Chromlu.
71 Kanianeae
76 Slclol
70 Copper
81 Hoc
81 Cadclua
83' Mercury


Mtnlsus)
Acute
Toxlclty
Effluent
(MATE) for
Ecology
300
33
1ft. OOP
30

30
SO
130
230
130
100
10
30
100
1
130
Cherry Hortb South Trll
loni Tributary to to Cherry
Kalo Steai Cherry Ron Upatreaa
tat tatted
rermdealble
CooceatratloB
(ETC)
for Eulogy Ku. Kin. Kax. Kin. Max. Mln.
fjjjjW) _(c) _____
JJ.(d) RD<() HD HD ID BD TO
— 13.600 16.300 10.300 17.400 JLSffil M.2BO
Jfl(b) .BD BD BD BD BD BD

Jfl.W> fil <30 iff. «SO M «SO
JA( HD HD HD HD BD HD
Ji(d> HD BD KD HD JQQ, KD
Jfl(d> BD BD BD BD BD BD
ja ' — — — — — —
'J&. Afifl IP ^AO, 20 no %a
I BD RD KD HD HD BO
J0.(d) FD ID BD BD HD ID
ittw) 23. m 20 20 30 30
JIAM> KD KD HD HD BD BD
ifl(dj BD KD BD BD BD BO
^nrary
tan
- Vler a Kun Tributary
telov Aab to
Dovnatream mapoaa] Area Vler'a Ron
Water Ouallty
Max. Kin.
	 _
RD HD
37.200 7.200
BD BD

 Data from.
(c) Data not i
W) Baaed no •





> en fives IB
r r r

r e a
r c a
r c e
VB/ll ETC ead HATE valoea an froa Oeland ead Ungabuiy (1977).
r

r
?
r

Cvaluatlof
Max.
10
RD
«ntsno
BD

jua
8
BD
BD
—
i.lOO
US.
m
120
KD
BD
,«"
Kin Ku. Din. '
KD 7 6
HD — —
86.000 — —
BD KD BD

Iffi - -
HD RD HD
KD — —
KD BD BD
_ _ _
1.400 — —
70 HD HP
KD RD RD
JO, 40 BD
BD BD BD
KD BD KD
tater'a
rood Com
Trlbntary

Max.
Jifl
20
IQr.OOO
KD

OiatQ
29
RD
BD
_
43.20O
640

1.730
i
BD

SinT"
e
iO
113.000
HD

JM
BD
HD
HD
_
1.110
SO
HD
159.
BD
HD
tarlna

Max. Mln.
yto ^
BD Hft
UQjsaa 102.300
3O 2Q

iViiXl 1.600
ifl J31
KD KD
40 20
~™ •.
jjsa «a
no a
ifl X.
122 221
± _l_
BD BD
Teo Uck


Ku.
a
BD
43. »00
RD

1.280
•KD
RD
BD
HD

RD
• HD
iia
BD
BD

KJn.
BD
BD
11.000
RD

ISO
RD

BD
HD
aa.
HD
RD
a.
BD
HO
teferace
Streaa
Dec-Apr

_
3.300
1

__
,j

10

J9

0
0
0
«o.s
E*alutlo«(l>






r e

r c
r c
r c-







V

r
r
r

r

r
r
t.

r

r
r
t













three sassllng csapalgn* contacted by lattelle la the a tody area
nrallable.
mat etrlagent

exlatloK or propoaed Federal etandard for water quality.


















(e) Cnt«lc«l aoalrsle Atria* water year 1973 of Young Vaaan's Creek near sanovo. fa.
•(I) ID - not detectable.
(g) The aquatic biota evaloi
C - Good: f » rain and
itlona an baaed 
-------
     Streams considered to have good biological quality also had
levels of pollutants which exceeded EPC or MATE values for the
environment.  Maximum and minimum levels of manganese and zinc in
streams with good aquatic biota quality exceeded the EPC values
for the environment.  Maximum levels, alone, of two additional
parameters  (ammonia and vanadium) in streams with good aquatic
biota quality also exceeded the EPC values for the environment.
Similarly, maximum and minimum levels of calcium and manganese in
streams with a good biological quality rating exceeded the MATE
values for the environment.

Stream Water Concentrations Versus Recommended Values

     MEG values have not yet been determined for 14 of the 30
water quality parameters measured in Battelle's study area.
Therefore, comparisons have been made between these 14 parameters
and 8 values recommended by the EPA  (1976) or suggested by McKee
and Wolfe (1963) (Table 4).  A biological quality evaluation of
the same stream stretches that were analyzed for water quality is
presented for comparison with the chemical data.
     All eight of the water quality criteria concentrations recom-
mended by EPA (1976) or McKee and Wolf (1963) were exceeded by
one or more concentrations of the same parameters measured in sam-
ples from streams in the study area  (Table 4).  The maximum and
minimum values for alkalinity, sulfate, and total solids observed
in one of the streams with a good biological quality rating were
greater than the recommended criteria concentrations.
                               781

-------
             Table 4.  S.urface water quality comparisons (yg/1) :

                       versus Homer City Data
Recommended criteria
oo
N>


' ' ttecoa.«««.M Crttarlfloi
*S5, rr........ ft., v
rSZmun 4Ta(k) felaa 4 Half1
. Ckanr Imi
Kala, (tail 	
i
if
•» kai Kla
Itruoa ID tba VlclolIT of Booar City Station 	
fcrth aotth TrttaMIT "I!'\I!r Tt"S"T "T^l" TO. lick
Tributary •» °-"T •— . •"-• aak To Fooo Too Uck
To Coarrr *-* f
^^^*^^^*^^~~°~~^^^^^^^~
	 OBI 	 Bla KM
Ultcr Quality Evaloatloo

Hma Ua ama IB
(era.
a Hta mm Ka. HU Haa Ho avataoi

acUltf . a* CoODj — '*' —
alaalUltf. ao Can, > 20.000 —
OB «.0-4.1 f.0-4.1
Total to 1.000 204)
•Iiaolaod l» — —
r."
Tot..! FfcaajhonM 10Q —
**l*tll* tell* — —
•Ur*t* - • 10.000 —
TotU U«l«.*l - • — —
Tut*l OvftOBlc CkctaB H ~*
Total aolUa — 101.000*4*
7,100 1.400
44,100 11.200
I.XO 140
740 <20
740 <100
11.400 17.100
40 «10
14.000 1.000
34.000 2.000
2,000 740
140 140
4,000 1.700
143.000 124.000
7.200 1.400 1.400
44.200 21.100 l>.tOO
1,710 140 110
10 40 to
420 «100 HO
17.300 27.300 247.000
100 10 10
10.000 1,200 10,400
41,000 7.000 30.000
1,420 140 1.000
140 <30 270
2,000 1,200 1,300
m.ooo 124.000 442.000

1.400 4.100 1.400
12.600 U.700 7.100
40 440 200
 IQoalltw Crltarla for Batar* (IT1, H74).
(c) ^tatar Qullly Crlt.rU' QUoa aa* Volt. 1*4]).
M) Oioalcal aaaljrala «aTU| aatar yoar 1171 of To«a Vbaao'o
((a) lot avallakla.
(S> UtUato* Vy aoaalai tka ^loaa ri an
00 Taa aaaatlc aloca •valattloat ara tmt
C- Oao4i r - Falri oo< t - roor taomtu
(1) D - aot oatactaklo.
lot for aaaxaooat
llota Qaalltr. 1
r
e
e
e
Croak oaar tamo. ro.
M tka atadj «roa
aad 41aaol»ad aolUa.
aractM dlvaraltj. aa4 an

r r
c r
c r
e r
oaac* of tnalcator aoaclaa or

r o
r o
r o
r e
faolliaa!
lo u tka ataay ataa.
T r r
• t » r
» » i
» ft


-------
     A comparison of the data for each of the 30 surface water



quality parameters with the biological quality evaluation for the



same stream segment suggests that values for four parameters agree



closely with the biological quality rating  (Tables 3 and 4).  The



maximum and minimum values for these four parameters (pH, sus-



pended solids, dissolved iron, and total organic carbon) have



been compared with recommended or suggested water quality cri-



teria in Table 5.  It can be seen that streams with good biologi-



cal quality did not have any levels of these four parameters



which were above the recommended criteria.  Maximum, and fre-



quently minimum, values of these four parameters, however,



exceeded the recommended criteria in streams with poor biological



quality.  The significance of these four "master" parameters to



aquatic biota is probably great because they affect the presence



of toxicity of other potential water pollutants.



     Several studies have described the effects of water pollu-



tants in acid mine drainage on aquatic biota.  These studies



found that the master chemical factors involved one or more of



the parameters listed in Table 5.  Weed and Rutschky (1972), for



example, found that pH, alkalinity, and ionic concentrations of



iron and sulfate were primarily responsible for altering the com-



munity structure and diversity of benthic macroinvertebrates.



Similarly, Warner (1971) found that pH measurements in streams



seemed to provide the most reliable, as well as unique, index of



the effects of acid mine drainage on aquatic life.  A report by



the Federal Water Pollution Control Administration  (1969)
                               783

-------
      Table 5.  Water quality parameters in close agreement
                with biota quality  rating
Sampling Sites
Water Quality
Parameter
pH (6.5-9.0) 
Suspended Solids
(20,000 yg/1) (c>
Dissolved Fe '
(1,000 yg/1) 
Total Organic Carbon
(4,000 yg/1) specif ied
1
1
0

0

1

2
F
2
0
0

0

0

0
G
3
0
0

0

0

0
G
4
1
1

0

1

3
P
5
1
1

1

1

4
P
6
2
2

2 .

1

7
P
value
7
2
2

1

2

7
P
(a) j
8
2
1

2

1

6
P
   (a)  Maximum and minimum units or concentrationsspecified value = 1;  maximum and
       minimum units  or concentrations>specified value = 2.

   (b)  Criteria recommended by EPA (1976).

   (c)  Criteria suggested on the basis of the chemical and biological data
       presented in this paper.

   (d)  G - good; F =  fair; P - poor quality.
concluded that acid mine  drainage damages  aquatic biota primarily

because of the high concentrations of mineral acids, the  ions of

iron,  sulfate, and the  deposition of a  smothering blanket of  pre-

cipitated iron salts on the stream bed.


Sediment Concentrations Versus  MEG Values


     EPC values for nine  trace  elements  (Pb,  As,  Cr, Mn, Ni,  Cu,

Zn, Cd,  and Hg) which were  measured in  stream sediments were

exceeded by both the maximum and minimum stream concentrations  for

eight of these elements (Table  6).  Comparisons of concentrations
                                784

-------
                           Table  6.    Sediment  quality comparisons  (ug/g):
                                          soil  versus  Homer  City  data
                                            MEG values for
Ln
Streams in the Vicinity of Homer City

MEG Category
and Substance
46 Lead
49 Arsenic
68 Chromium
71 .Manganese
76 Nickel
78 Copper
81 Zinc
82 Cadmium
83 Mercury

MATE
for
Ecology
10
10
50
20
2
10
20
0.2
50

KPC
for
Ecology
_2
10
4
0.4
20
0.01(d>
3(d)
Cherry
Run:
Main Stem
Upstream
On South
Tributary
To
i Cherry Run
Station
Hiet's Run
Below Ash
Disposal Area
Concentrations in Stream
Max. Min
50 19
15 4
346 84
2,830 248
207 71
440 23
387 _75
1.0 0
Max.
63
.8 9.
225
1.430
130
310
677
.5 1.
Min.
36
6 6.6
157
612 1,
115
120
244
0 0.5
Max.
29
19
197
,000
117
270
210
0.4
0.25 0.010 0.016 0.016 0.15
Biological Quality Evaluation






Two Lick
Creek
Sediments ^
Min.
2
7.6
102
349
71
Max.
85
21.5
132.5
251.5
79
25 230
65 207
0.2 0.55
0.024 0.53
(g)
Min.
48.
10
90
210
33
i*
108
0.55
0.42
Analysis (e)
Max.
14
5.4
144
75
126
12
0.6
0.14
Min.
12
3.8
112
sr
71
90
40
0.6
<0.005
Analysis
of Three ...
Raw Coals1'
Max.
17.8
49
36
76
17.5
32
ii
0.27
1.1
Min.
12.3
23
31
36
13.2
21
0.1
0.35
          Attached Algae

          Bottom-Dwelling
          Invertebrates

          Fish

          Overall
P

F

F
G

C

G
P

P

P
P
r
p
          (a)  MEG - Multimedia Environmental Goals from Cleland and Klngsbury (1977);  all values were  multiplied by 100 based on
              personal communication with Klngsbury  (August,  1978); all values in ug/g dry weight.
          (b)  MATE - Minimum Acute Toxicity Effluent; EPC - Estimated Permissible Concentrations.
          (c)  Based on three sampling campaigns  conducted by  Battelle in the stud; area.
          (d)  Based on potential teratogenic effects.
          (e)  Sampled in ash disposal area.
          (f)  Raw coals sampled at Homer City include those from:  Helen Mining Co. and Helvetia Coal  Co. (from Upper Freeport Seam) and
              Trucked-in Coal (from Lower Klttanning Seam).
          (g)  The aquatic biota evaluations are  based on standing crop, species diversity? and presence of indicator species  or families;
              G - Good; F - Fair;  and P • Poor Aquatic Biota  Quality.
          (h)  Ho data available.

-------
 for the same nine elements in fly ash from the ash disposal area



 revealed that maximum and minimum ash concentrations of six ele-



 ments exceeded their associated MATE and EPC values.  Maximum and



 minimum concentrations of all of these elements, except chromium,



 mercury, and cadmium, were higher in separate grab sample analyses



 of the three raw coals used in the Homer City Power Complex than



 they were in the associated MATE or EPC values.  Therefore, coal



 and fly ash from a variety of sources may be contributing to the



 trace element content in the sediments of the study area streams.



      In spite of the toxic trace elements in its sediments, one



 stream in the study area still had a good biological rating



 (Table 6).   The upstream portion of the south tributary to Cherry



 Run had good biological  quality.  This stream,  however,  had maxi-



 mum and minimum concentrations of seven elements (Pb,  Cr,  Mn,  Ni,



 Cu,  Zn, and cd)  that exceeded the associated MATE and  EPC values.





                 Conclusions  and  Recommendations





 Pollutant  Toxicity Considerations






      Several factors confounding pollutant  toxicity evaluations



 need  to be  considered when comparisons  are  made between  EPC



 values  and  field data on  pollutant  concentrations  and  biological



 quality.  First, the EPC  values  have not  incorporated  interactive



 effects  of  pollutant combinations,  such as  synergism or  antagon-



 ism.   (Antagonistic  effects between pollutants  measured  in  stream



water and sediments  may explain  how some  EPC's  for  ecology  were



exceeded in  streams  that  had a good biological  quality rating.)
                               786

-------
 Second,  EPC's and field chemical data frequently involve  only
 total elemental concentrations.   Biota in the ambient environment,
 however,  may be adversely affected only by specific  compounds or
 ions of  an element that are relatively stable in the ambient
 media and not by other  compounds that are included in the  total
 elemental concentration.   To date,  EPC values for inorganics  have
 been determined primarily for groups  of compounds which have  a
 common parent element;  comparatively  few of the  individual,
 highly toxic  compounds  within these groups that  are  also relatively
 stable in the environment have been evaluated for an EPC.  Third,
 some of the water  quality parameters  which are extremely important
 in making an  environmental  assessment of coal-related effluents on
 aquatic biota do not presently have EPC's.  These master parame-
 ters,  including suspended solids,  pH,  alkalinity, etc., are
 planned for future EPC  evaluation.
 Fugitive  Dust

      Elemental  concentrations in fugitive  dust which were measured
 in the study  area exceeded  both  EPC and  MATE  values  for air and
 soil  quality.   For example,  three out  of  15 elements  analyzed  in
 fugitive dust had concentrations  above  the health-based EPC's  for
 air quality.  Comparisons with ecology-based  EPC's for air
quality,  however, were very  difficult  because  of the  absence of
ten EPC values.
     Although no soil concentrations were  determined,  comparisons
of elemental concentrations  in fugitive dust were made with ecology-
                              787

-------
 based EPC's for soil because of the potential problem of toxic ele-
 ments leaching into the soil from fugitive dust laying on the
 ground.   Eleven of the 15  elements studied had concentrations in
 the fugitive dust which were above the  ecology-based EPC's for
 soil.  Thus, additional research needs  to be conducted to deter-
 mine if  leaching is a problem.   The existence of this type of
 problem,  however,  seems to be inconsistent with the  condition of
 the vegetation in the area.   In spite of  the dust (particularly
 coal dust)  present on the  ground for some distance around the coal
 pile,  the vegetation has not yet begun  to show any obvious ad-
 verse effects.

 Stream Water,  Sediments, and Biota

      Of the  30  water quality parameters measured in  streams,  only
 15  parameters  have associated MEG values.   Thus,  some of the  sur-
 face  water quality data  were compared with the  MEG's  and some were
 compared  with  other  available criteria.   The  maximum  and minimum
 of  10  parameters exceeded  the corresponding  EPC's for the environ-
 ment.  In fact, maximum, and some  minimum levels, of  four pollu-
 tants  (ammonia, vanadium, manganese, and  zinc)  exceeded  the appro-
 priate EPC values, even  in streams considered to have good biolog-
 ical quality.  This apparent  discrepancy  needs  to be  further  eval-
uated both in terms of the validity of the proposed EPC  values
used, and in terms of the interactions and uniqueness of  the  chem-
 ical and biological conditions encountered in the study  area
streams.
                               788

-------
     Fifteen water quality parameters evaluated in Battelle's
study do not have corresponding MEG values; these parameters were
compared with criteria from the EPA  (1976) and McKee and Wolf
(1963).  Values for four of these parameters  (pH, suspended solids,
dissolved iron, and total organic carbon) were in close agreement
with the biota quality evaluation.
     Elemental concentrations in stream sediments were consider-
ably higher than the corresponding MEG values.  Maximum and mini-
mum concentrations of eight elements in sediments exceeded the
associated EPC's and MATE'S for ecology.  This situation occurred
for seven elements, even in a stream with good biological quality.
Again, the field situation and proposed EPC values need to be
evaluated in more detail to determine if a discrepancy exists.

Future Studies Recommended

     Additional research needs to be conducted on EPC and MATE
values before they can be used to evaluate and rank pollutants
for the purpose of environmental assessment.  Much of this work
was recommended in the initial MEG document (Cleland and Kings-
bury, 1977a)  and is now or will soon be in progress.  For example,
MEG's need to be related to the specific compounds or ionic forms
of an element which are most toxic, rather than having a single
value represent all compounds and ions which have a common "par-
ent" element.  Synergistic and antagonistic effects need to be
considered because the may drastically change the hazard ranking
of a pollutant in a specific situation.  MEG's are also'needed
                               789

-------
 for many of the master parameters, such as the "totals" identi-
 fied by Cleland and Kingsbury (1977a:  155}  (e.g., total particu-
 lates)  or the water quality parameters identified in this study
 (e.g.,  pH,  suspended solids, dissovled iron,  and total organic
 carbon).
      In another vein,  the comparison of trace element concentra-
 tions in  fugitive dust to MEG values points out the need for  lab-
 oratory and field research,  particularly in relation to fugitive
 dust  that consists predominantly  of  coal particles.   First, the
 rates at  which  toxic elements leach  from coal  dust into a variety
 of  soil types need to  be  explored.   Second, the concentrations  of
 toxic elements  present in the soil around a large,  open coal  pile
 need  to be  determined  when this pile  has been  in  existence for  a
 long  period of  time.   Third,  laboratory  bioassay  and  long-term
 field studies need  to  be  conducted on  the effects  of  coal dust  on
 plants and  animals.
      It is  important that  the type of  research  necessary to improve
 and expand  the  initial MEG approach to environmental  assessment be
completed soon.   Once the MEG methodology has been refined it will
become an essential part of any assessment of environmental pollu-
tion.
                             790

-------
                           REFERENCES


American Society of Agronomy and ASTM.  1965.  Methods of soil
     analysis.  C. A. Black (Ed.), Madison, Wisconsin.

Cleland, J. G., and G. L. Kingsbury.  1977a.  Multimedia environ-
     mental goals for environmental assessment, Vol. 1.  Prepared
     for U.S. Environmental Protection Agency, Industrial Environ-
     mental Research Laboratory, Research Triangle Park, North
     Carolina, EPA-600/7-77-136a.

Cleland, J. G., and G. L, Kingsbury.  1977b.  Multimedia environ-
     mental goals for environmental assessment, Vol. II:  MEG
     charts and background information.  Prepared for U.S. Envi-
     ronmental Protection Agency, Industrial Environmental Research
     Laboratory, Research Triangle Park, North Carolina, EPA-600/
     7-77-136b.

Dvorak, A. J., B. G. Lewis, P. C. Chee, E. H. Dettmann, R. F.
     Freeman III, R. M. Goldstein, R. R. Hinchman, J. D. Jastrow,
     F. C. Kornegay, D. L. Mabes, P. A. Merry, E. D. Pentecost,
     J. C. Prioleau, L. F. Soholt, W. S. Vinikour, and E. W. Wai-
     bridge.  1978.  Impacts of coal-fired power plants on fish,
     wildlife, and their habitats.  Prepared for Fish and Wildlife
     Service, U.S. Department of the Interior, Washington, D.C.,
     FWS/OBS-78/29.

Environmental Sciences, Inc.  1972.  The environmental status of
     operations at the Homer City Generating Station.  Environ-
     mental Sciences, Inc., Pittsburgh, Pennsylvania.

Federal Water Pollution Control Administration.  1969.  Stream
     pollution by coal mine drainage in Appalachia.  Federal Water
     Pollution Control Administration, U.S. Department of the
     Interior, Cincinnati, Ohio.

Furr, A. K., T. F. Parkinson,  R. A. Hinrichs, D. R. Van Campen,
     C. A. Bache, W. H. Gutenmann, L. E. St. John, Jr., I. S.
     Pakkala, and D. J. Lisk.   1977.  National survey of elements
     and radioactivity in fly ashes:  absorption of elements by
     cabbage grown in fly ash-soil mixtures.  Environmental
     Science and Technology, 11(13):1194-1201.

Hem, J. D.  1970.  Study and interpretation of the chemical char-
     acteristics of natural water.  Water Supply Paper 1473,
     U.S. Geological Survey, 363 pp.

Jackson, D. R., and A. P. Watson.  1977.  Disruption of nutrient
     pools and transport of heavy metals in a forested watershed
     near a lead smelter.  Journal of Environmental Quality
     6(4) :331-338.
                               791

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Kerin, Z.  1975.  Relationship between lead content in the soil
     and in the plants contaminated by industrial emissions of
     lead aerosols.  Pages 487-502.  In T. C. Hutchinson  (Chief
     Ed.), International conference on heavy metals in the environ-
     ment.  Vol. II, Part 2.  Symposium was held in Toronto,
     Ontario, Canada, October 27-31, 1975.

McKee, J. E., and H. W. Wolf.  1963.  Water quality criteria, 2nd
     edition.  State Water Resources Control Board, Sacramento,
     California.

Shannon, C. E., and W. Weaver.  1963.  The mathematical theory of
     communication.  University of Illinois Press, Urbana, Illinois.

Stumm, W., and Morgan, J. J.  1970.  Aquatic chemistry—an intro-
     duction emphasizing chemical equilibria in natural waters,
     John Wiley and Sons, New York, 583 pp.

Stumm, W.  The chemistry of natural waters in relation to water
     quality.  Unpublished, 26 pp.

Stumm, W., and G. F. Lee.  1960.  The chemistry of aqueous iron.
     Sonderabdruck aus schweizerische zeitschrift fur hydrologie,
     Birkhauser Verlag Basel, Vo. 21, Fasc. I.

U.S. Department of the Interior.  1974.  Water resources data for
     Pennsylvania, Part 2.  Water quality records, Geological
     Survey.

U.S. Environmental Protection Agency.  1976.  Quality criteria for
     water.  U.S. Environmental Protection Agency, Washington, D.c.

U.S. Environmental Protection Agency.  1969.  Chemistry laboratory
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Vaughan, B. E., K. H. Abel, D. A. Cataldo, J. M Hales, C. E. Hane,
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     Wolf.  1975.  Review of potential impact on health and envi-
     ronmental quality from metals entering the environment as a
     result of coal utilization.  Battelle Energy Program Report,
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Warner, R. W.  1971.  Distribution of biota in a stream polluted
     by acid mine drainage.  Ohio J. Sci. 71(4):202-215.

Weed, C. E., and C. W. Rutschky, III.  1972.  Benthic macroinver-
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                              792

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                     AN OVERVIEW OF CONTROL TECHNOLOGY

              A. W. Lemraon, Jr., G. L. Robinson, and D. A; Sharp
                      Battelle's Columbus Laboratories
                               Columbus, Ohio
                                  ABSTRACT


     An important objective of coal cleaning processes is to reduce the con-
centrations of pollutants in coal prior to its utilization so that the emissions
from utilizing the coal may be reduced.  Coal cleaning is an environmental
trade-off; that is, the potential pollutants are being transferred from one
segment of the environment to another.  Through coal cleaning, highly mobile
air pollutants which may be discharged by the burning of raw coal may be
removed from the cycle as, for example, a solid refuse.  But this solid
refuse and other wastes generated by cleaning can be important sources of
environmental contamination.

     As a means of evaluating the full implications of coal cleaning tech-
niques as, for example, a combustion emission control measure, the extent
of environmental contamination resulting from coal cleaning technology appli-
cations and the control technology for this potential source of contamination
needs to be adequately assessed.  This paper is a report of progress in
quantifying the potential emissions from physical coal cleaning facilities,
in evaluating the applicable pollution control technologies for minimizing
adverse effects of discharges from these facilities, and in defining and
costing these technologies.  Needs for and plans for gathering further
information are also discussed.
                                     793

-------
                              INTRODUCTION

          An important objective of coal cleaning is to reduce the concen-
trations of pollutants in coal prior to its utilization so that the emissions
from utilizing the coal may be reduced.  Coal cleaning is an environmental
trade-off; i.e., the potential pollutants are transferred from one segment
of the environment to another.  Through coal cleaning, highly mobile air
pollutants which may be discharged by the burning of raw coal may be removed
from the cycle as, for example, a solid refuse.  But this solid refuse and
other wastes generated by cleaning can be important sources of environmental
contamination.
          As a means of evaluating the full implications of coal cleaning
techniques as, for example, a conbustion emission control measure, the
extent of environmental contamination resulting from coal cleaning technology
applications and the control technology for this potential source of contami-
nation needs to be adequately assessed.  This paper is a report of progress
in quantifying the potential emissions from physical coal cleaning facilities,
in evaluating the applicable pollution control technologies for minimizing
adverse effects of discharges from these facilities, and in defining and costing
these technologies.

                           TYPES OF PROCESSING
                        AND SOURCES OF POLLUTANTS

          Coal preparation plants in general include the functions of (1)
size reduction and screening (which may include some separation of impurities
                                    794

-------
from coal), (2) separation of coal from its impurities (in a more sophisticated
manner), and (3) dewatering and drying.  Table 1 shows the various unit
processes that may be employed for coal cleaning while Figure 1 depicts a
typical arrangement of unit processes that could be used in a 1000-ton/hour
cleaning plant.  This figure should provide a common basis and understanding
for use in the following discussions.

                      Size Reduction and Screening

          Size reduction and screening are basic and common to all types of
coal preparation plants.  Some coal preparation plants involve only size
reduction and screening functions.  A variety of comminution units, primarily
crushers and breakers, are employed for size reduction.  Screens usually are
employed in conjunction with crushers to provide additional sizing of coal.
Solid waste produced from crushing nad sizing operations consists of coarse
rock and tramp iron.  Typically, the amount is less than one percent of the
raw coal feed, so that, because of this >small amount, it is not a significant
disposal problem in comparison with more sophisticated processing operations.
Because crushing and sizing is usually a dry process, water pollution potential
is limited basically to surface run-off near the plant.
          Crushing and sizing of dry coal can be a major source of dust
generation.  As an air pollutant, coal dust can be classified into two
categories based on the particle sizes.  The first category consists of
relatively large particles  (plus 10-micron size range) and is primarily
responsible for the environmental hazards of impaired visibility and explosions.
These particles tend to settle quickly and thus move out of the air environ-
ment much faster than particles of smaller sizes.  Furthermore, these particles
are readily suppressed by simple water spraying techniques. " Consequently,
coal dust in the plus 10-micron size range is not normally considered as a
serious environmental hazard.
          The  second category of  coal  dust consists of minus 10-micron
particles and  often is defined as  respirable dust.  Generally,  these
particles do not impair visibility,  but  they can be inhaled and  affect  human
respiratory systems.  In particular, minus one-micron  particles  from  coal
                                    795

-------
TABLE 1.  UNIT PROCESSES EMPLOYED IN
          COAL CLEANING OPERATIONS
    Size Reduction and Screening
              Crushing
              Screening
      Separation of Impurities
                Jigs
        Dense Medium Vessels
             Air Tables
      Wet Concentrating Tables
        Dense Medium Cyclones
            Hydrocyclones
           Froth Flotation

        Dewatering and Drying
        Mechanical Dewatering
           Thermal Drying
                   796

-------
ROM coal
1000 tph
crushing and sizing
circuit
refuse
*• (1U tph)
VO
water
3000 gi
recycle
water
>n

wet sc
at 3/1
i
wet sc
at 28
,
hydroc>
id

water
3450 gpa
:reen *
5 In.
water
2800 gpm
.reen f
M ^




-* " i 1
* 1 1

coarse-size coal

t
refuse
(170 tph)
concentrating table mechanical

*
refuse
(50 tph)








-^
clean coal

••*• product
740 tph
thermal
drying

                                                               thickener underflow (30 tph)

                                FIGURE 1.  FLOW DIAGRAM OF A TYPICAL CONCENTRATING TABLE AND HYDROCTCLONE
                                           PLANT HANDLING 1000 TPH OF RAW COAL

-------
are critical with respect to human health (e.g., the inhalation of these small
particles is responsible for the occupational lung disease pneumoconiosis).
Moreover, these small particles are much more difficult to control than
larger particles.  Therefore, respirable dust is the main concern in air
pollution control.  Figure 2 shows the large number of respirable dust
particles which is created by coal crushing, giving an indication of the
potential for effects which may occur as a result.

                        Separation of Impurities

Solid Waste

          Solid waste resulting from separation processes includes coarse
refuse from Jigs and dense-medium vessels; fine refuse from air tables, dense-
medium cyclones, wet concentrating tables and hydrocyclones; sludge from
water clarification circuits; magnetite from dense-medium processes (0.5 Ib/ton
of feed coal); and chemical reagents from froth flotation processes.  These
processes, applied to medium and fine-sized feed coal streams, generate on
the order of 25 percent of their coal feed as waste.

Water Pollution

          The consequence of wet separation of coal is the generation of
contaminated water.  The characteristics of process water are highly dependent
upon the characteristics of coal being processed and the particular process
or recovery technique utilized in the operation.  The principal pollutant
present in process water is suspended solids.  Some minerals also are present
as dissolved solids.   Among the major pollutant constituents or parameters
identified in effluents from coal preparation plants are:
           Acidity or Alkalinity       Total Suspended Solids
           Total Iron                  Total Dissolved Solids
           Dissolved  Iron              Sulfates
           Ammonia.
                                    798

-------
     28,000  r—
Ji
to
M
•4-1

O
m
9)
&
u
0>
•8
M
•H
P.
CO
     24,000
     20,000
     16,000
     12,000
      8,000
     4,000
                       Particle

                       Size  (pro)



                       O  0.50-1.50

                          1.50-2.50

                              -3.50

                                 50
          0.12
0.16
                                                           0.20
                                                0.24
                             Size Reduction Ratio
      FIGURE 2.  AIRBORNE RESPIRABLE DUST GENERATION FROM COAL  CRUSHING(1)
                                         799"

-------
          Process water from dense media processes may contain magnetite;
water from froth flotation operations may contain potentially toxic or noxious
chemical reagents.  The quantities of water used in processing range from
180 to 1800 gallons per ton of coal processed.  A major portion of the water
used in coal cleaning is recirculated.

Air Pollution

          Of the separation processes, only air tables may contribute to air  .
pollution.  Emissions from pneumatic coal cleaning consist of particulates
only, because ambient air is used to separate coal from refuse.  The quantity
and pressure of the air used depends on the size and kind of coal to be
cleaned.  For pneumatic cleaning of minus 3/8-r-inch coal, an average volume
of exhaust air is about 14,100 cu ft per ton of feed coal.  The exhaust
air usually picks up about 65 to 70 percent of the minus 48 mesh material
in the feed coal, and about 20 percent of minus 3/8-inch coal is smaller than
48 mesh.  Therefore, the uncontrolled exhaust air contains abr at 260 to 280
pounds of dust per ton of feed coal treated or 128 to 138 grains of dust per
cubic foot.

                          Drying and Dewatering

          Solid waste from drying and dewatering  includes sludges from the
air pollution control equipment (usually scrubbers) on the thermal dryers.
These scrubbers also generate considerable amounts of contaminated water
(lesser amounts, of course, when the usual practice of recirculation is used).
          Air emissions from thermal dryers include particulates from the
coal being dried and particulates in the form of fly ash from the coal-fired
furnace that supplies the drying gases.  Gaseous emissions from thermal
dryers include carbon monoxide, carbon dioxide, hydrocarbons, sulfur dioxide,
and oxides of nitrogen—all furnace combustion products.  Table 2 shows typical
emission ranges of some of the gaseous emissions.  These are the uncontrolled
levels and no case is known in which control of S02, for example, is exercised.
Regardless, the contribution, per ton of coal, to pollutant emissions caused
                                     800

-------
TABLE 2.  GASEOUS EMISSIONS FROM THERMAL DRYERS
                                               (2,3)
                  Emission Rate,
                     Ib/ton of        Concentration,
Pollutant	coal dried	ppm	

N02                    0.2              40 to 70

S02                0.38 x (%S)           0 to 11.2


CO                     0.03                 50
Hydrocarbons           0.01             20 to 100
  as methane
                           801

-------
by coal drying Is very small In comparison to the total emissions produced
subsequently during the burning of the clean coal product.

                       Coal Storage. Handling, and
                        Transportation Operations

          Storage of coal is an economic necessity in coal preparation.  It
provides a reserve against production interruptions and also facilitates
intermittent shipment.  Coal is stored in open piles or enclosed bins and
silos.  Transportation of coal from mines or preparation plants to the
point of consumption is one of the most important factors affecting coal
utilization.  Transportation modes are rail, waterway, truck, pipeline,
and belt conveyor.  In conjunction with the transportation and storage of
coal, a wide variety of material handling operations is needed.  This includes
loading and unloading, stacking and reclaiming, and transferring coal in a
plant.

Water Pollution

          Outdoor coal piles have very large surface areas, and coal residence
times in them are relatively long so that rainwater has a chance to react,
form acids, and extract sulfur compounds as well as soluble metal ions.  Coal
pile leachate is generally similar to acid mine drainage.  The quantity of
coal pile leachate is highly variable, both in an absolute sense and with
time.  It depends upon the topography and drainage area of the coal pile
site, the configuration and the volume of the stock pile, and the type and
intensity of precipitation.  Table 3 shows a typical composition of coal pile
drainage.  Its composition is not much different than acid mine drainage.
Obviously, then, control and treatment of this drainage must be exercised
for proper protection of the environment to be achieved.
          In addition to the coal pile leachate, accidental spills from
barge transport and coal slurry pipelines may produce serious water pollution
problems; however, no relevant quantitative data covering these situations
have been found in the literature.
                                    802

-------
      TABLE 3.   TYPICAL COMPOSITION OF DRAINAGE
                FROM COAL PILES<4)
	Concentration, mg/1
Alkalinity (as CaCO-)               15 - 80
BOD                                  3-10
COD                                100 - 1,000
Total solids                     1,500 - 45,000
Total suspended solids              20 - 3,300
Total dissolved solids             700 - 44,000
Nitrate                            0.3 - 2.3
Phosphorus                         0.2 - 1.2
Total hardness (as CaC03)          130 - 1,850
Sulfate                            130 - 20,000
Iron                               0.4 - 2.0
PH                                 2.2 - 8.0
*Except pH
                         803

-------
 Air Pollution

           The principal air pollutant from storage,  transportation,  and
 handling of coal is fugitive coal dust.   This  dust has  the particle  size
 distribution characteristics shown in Table 4.   The  amount of  dust generated
 varies widely,  depending on such factors  as climate,  topography,  and
 characteristics of coal,  including moisture content.  Thus,  for  example,
 the handling of thermally dried  coal  would result in the  generation  of
 more dust than would be generated with undried  coal.  It  is  estimated that as
 much as about 80 pounds of coal  per ton hauled  are lost as fugitive  dust
 during the transport and handling operations.   A dust emission factor from
 coal storage piles has  been estimated to  be equal to  approximately 0.00118
 lb/ton-year (0.59 mg/kg-yr).

                         Coal Waste Disposal Areas

           Coal  refuse consists of waste coal, slate,  carbonaceous and pyritic
 shales,  and clay associated with a coal seam.   It varies  considerably in
 physical and chemical characteristics, depending on both  its source  and
 the nature of the preparation process.  It  is estimated that about 25 percent
 of  raw coal mined is disposed of as waste.   Over 3 billion tons of solid
 waste  have accumulated  in the United  States, and the  total number of active
 and abandoned coal waste  dumps is  estimated to  be between  3000 and 5000.
 About  one-half  of these pose some  type of health, environmental, or  safety
 problem.

 Water  Pollution

           The weathering  and leaching of coal refuse  dumps produces  several
 types  of water  pollution.   These  include silt,  acids, and  other dissolved
mineral matter.   Pollution  from  coal waste  dumps is similar to that  from
 surface mines;  i.e., waste water from a refuse  disposal area can continue
 indefinitely  to pollute after the disposal  has  ceased, and volumes of waste
water  are highly  dependent on precipitation and surface water flow patterns.
                                     804

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         TABLE  4.   PARTICLE SIZE  DISTRIBUTION OF
                   AIRBORNE COAL
  Particle          Mean                             Rate of
Radius Ratige,   Particle Radius,                    Settling,
    (pm)   	(ym)	  Weight Percent	fm/sec)
    < 3               2                 2             0.0005
    3_6               43             0.002
    6-15              9                21             0.012
   15-30             20                30             0.047
    > 30             30                44             0.247
                            805

-------
           Siltation from coal  refuse  dumps  is  caused  by finely divided coal,
 minerals,  and discarded  soil.  Acid drainage is  produced when iron sulfides
 are  exposed  to air  and water.  Acid drainage is  one of  the most serious
 water pollution problems in many parts  of the  U.S.  In  Appalachla alone,
 more than  10,000 miles of streams  are affected by acids from coal mines and
 refuse dumps.

 Air  Pollution

           Burning refuse piles present  a difficult air  pollution problem.
 The  oxidation of residual coal or  other mineral  matter  in coal refuse  piles
 can  produce  sufficient heat to ignite the interior of the pile.   These
 burning wastes emit  fumes including carbon monoxide,  sulfur  oxides, and
 hydrocarbons.   Some  waste piles have  been burning continuously for over
 20 years,  and  approximately 300 coal  waste piles are  still burning.
                  CHANGES IN DISTRIBUTION OF POLLUTANTS

          Recently, the fate of potentially toxic elements in coal during
coal cleaning has received special attention.  Coal has been found to contain
nearly every naturally occurring element.  Coal cleaning affects the distri-
bution of these elements between clean coal and refuse portions.  Table 5
shows the concentrations of a few selected elements in raw coal, clean coal
at 75 percent weight recovery, and in the resulting refuse.  The enrichment
factor is defined as the concentration of an element in the clean coal (or
in the refuse) divided by the concentration of the same element in raw coal.
Of 29 elements measured in this way by the Illinois State Geological Survey,
all but boron and germanium had higher concentrations in the refuse than in
the raw coal.  Beryllium is distributed approximately evenly between the clean
coal and the refuse.
          Reduction of trace elements is an added benefit of coal cleaning
for reducing the environmental pollution from burning coal; hwoever, the
concentration of trace elements in the solid waste may increase the potential
for environmental contamination from this source.  These materials can be
                                   806

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TABLE 5.  ENRICHMENT FACTORS IN FLOAT-SINK SEPARATION
          OF ILLINOIS COALS(6)
Element
S
As
Be
Ge
Se
Concentration
ppm (unless otherwise
Raw Coal
4.4 %
11.5
3.0
6.7
2.8
Clean Coal
1.6 %
1.5
2.9
8.1
1.3
»
stated)
Refuse
12.9 %
41.0
3.3
2.3
7.3
Enrichment Factor
Clean Coal
0.36
0.13
0.97
1.21
0.46
Refuse
2.93
3.57
1.10
0.34
2.61
                          807

-------
subjected to leaching by rainwater or surface flows that could produce water
pollution problems.  In addition,  under certain conditions, burning refuse
piles could discharge some of these elements into the atmosphere.   Hence, the
environmental consequences of solid refuse disposal should be carefully
assessed.
                    AIR POLLUTION CONTROL TECHNIQUES

          Several types of air pollution control devices are available for
application to coal cleaning operations.  In choosing a particular technique
for application, the factors listed in Table 6 must be considered.  The
choice of the control device depends also on the type of pollutant (particulate
or gaseous); the properties of the pollutant (such as size, density,  and shape
for particulates, and equilibrium solubility, reactivity, and adsorptivity
for gases); and the properties of the conveying medium (such as density,
temperature, and velocity).  Particulate control devices may be broadly classi-
fied as dry inertial collectors (gravity settling chambers and cyclones),
filters,  wet scrubbers, and electrostatic precipitators.  Electrostatic
precipitators are not used at coal cleaning plants because of the explosive
nature of coal-dust-air mixtures and the charged field in the precipitator.
Control devices for the removal of gases or vapors involve" adsorption or
absorption in a variety of contacting devices.  Table 7 lists the mechanisms
and types of equipment in common use today for the removal of the two basic
air pollutant types.

                       Particulate Control Devices

Dry Inertial Collectors

          Dry inertial collection systems utilize either gravitational or
inertial forces to separate the particulates from the gas stream.  The collection
systems are characterized by moderate removal efficiencies, low energy require-
ments, low capital and operating costs, and an ability to accommodate high
inlet dust loadings and operate at high temperatures.  For applications at
                                    808

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  TABLE 6.  FACTORS FOR EVALUATION OF AIR POLLUTION
            CONTROL TECHNIQUES

      (1)  Characteristics of air emissions and
          operational constraints
      (2)  Control technology removal efficiency
      (3)  Capital and operating costs
      (4)  Disposal of wastes
TABLE 7.  LISTING OF AIR POLLUTION CONTROL EQUIPMENT
    Control of Particulates
   Control  of.
Gases and Odors
    Dry Inertial Collectors
      Gravity Settling Chambers
      Cyclones
    Fabric Filters
    Electrostatic Precipitators
    Wet Inertial Scrubbers
      Impingement
      Centrifugal
      Venturi
      Self-Induced
 Dry Adsorbers
 Wet Absorbers
                         809

-------
coal cleaning plants, the inertial collectors are used primarily as scalping
units or precleaners to remove the major volume of particulates from
pneumatic cleaner and thermal dryer off-gases.  To meet the particulate
emission standards, the collectors are generally followed by more efficient
removal devices, such as high-energy scrubbers or filters.

Fabric Filters

          Fabric or bag filters are regarded as one of the simplest and most
reliable high-efficiency dry collector devices, being capable of 99.9 percent
removal of submicron size particles.  They are suitable for a wide variety
of dry particulate removal applications and, depending on the type of fabric
selected, are resistant to chemical and mechanical rigors and are operable
at moderately high temperatures.

Wet Inertial Scrubbers

          Wet scrubbers or collectors utilize a liquid, generally water, to
assist in removing the dust particles from the gas stream.  The major features
that make wet collectors popular dust control devices are their high removal
efficiencies, ability to remove gaseous pollutants, tolerance of moisture in
the gas, and relatively low capital costs.  Disadvantages inherent with wet
collectors in general include the following:  (1) the captured particulate
is in the liquid state and sometimes presents a water or waste disposal
problem, (2) the scrubber internals are subject to plugging and corrosion,
(3) the scrubbed gas is saturated with the liquid vapor, and (4) the energy
requirements for some units are high, which results in higher operating costs
than for some dry collectors.  Four types of the more common types of wet
collectors used for particulate control are the impingement, centrifugal,
venturi, and self-induced spray scrubbers.

Evaluation of Particulate Collection Devices

          On the basis of the characteristics outlined for the three major
emissions from coal cleaning unit operations and the performance evaluation
                                    810

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of the control equipment, those equipment types most appropriate as control
equipment for each major emission may be selected.  The appropriate control
selections are presented in Table 8.

Gaseous Removal and/or Collection Devices

          Gaseous removal and/or collection devices are designed to extract
specific gaseous compounds from a carrier gas stream.  Although not practiced
to date, the major potential application of gaseous removal devices in coal
cleaning operations is for the removal of S02 from thermal dryer off-gases.
To this end, two major types of gaseous removal processes, dry adsorption
and wet absorption, can be considered for controlling sulfur dioxide emissions.
Both processes have achieved commercial status in flue gas desulfurization
for utility and industrial boilers.  They are not, however, efficient dust
removal devices, and, to meet particulate control regulations, they must be
used in conjunction with or preceded by a high-efficiency wet scrubber.

Dry Adsorbers

          Removal of sulfur dioxide from flue gas or drier off-gas may be
accomplished by either molecular sieves or carbon adsorption.  Unfortunately,
molecular sieves have a greater affinity for water than for S0», and since
water in flue gas or drier off-gas is present in considerably greater concen-
trations than SCL, the sieve is rendered essentially ineffective unless
preceded by a drying device, i.e., another sieve.

Wet Absorbers

          Absorption is regarded as the most developed method for removing SO-
from flue gases, and, to date, several hundred various commercial-size installa-
tions have been applied worldwide to utility and industrial boilers.
          Several different types of absorption equipment are utilized to
effect contact of the gas with the scrubbing slurry; some of the more common
types are spray towers, venturi scrubbers, and marble bed scrubbers.  A
variety of different aqueous solutions are also utilized to capture the SO^.

                                    811

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           TABLE 8.   SUMMARY OF APPLICATIONS FOR PARTICULATE
                     CONTROL EQUIPMENT
Emission Source
        Typical
Characteristics of Dust
Appropriate
   Control
Crushing and Sizing
  Operations
Pneumatic Cleaners
Thermal Dryer
Dry, submicron up to about
6 microns In size; light
dust load, ambient temperature

Dry, submicron up to 48 mesh
in size, heavy dust load
(>100 gr/dscf), ambient
temperature
High humidity, submicron up
to about 100 microns in size,
heavy loadings up to 200 gr/
dscf, temperature 200 to 250 F.
Cloth filters or
  high-energy
  wet scrubbers

Primary cyclone-
  cloth filter or
  primary cyclone-
  high-energy
  wet scrubber

Primary cyclone-
  high efficiency
  wet scrubber
                                  812

-------
They may be classified into four different categories:   slurry solutions,
clear solutions, weak acid solutions, and organic liquids.   The most developed
systems to date are those utilizing slurry solutions in spray towers or
venturi scrubbers.
                   WATER POLLUTION CONTROL TECHNOLOGY

          Process and scrubbing water effluents from coal cleaning operations
contain two types of pollutants:  suspended materials (solid or liquid) and
dissolved substances.  The technology available for removing suspended
materials from the water includes mechanical dewatering, sedimentation, and
flotation.  Dissolved substances can be removed from water or converted to
less objectionable forms by neutralization, adsorption, ion exchange, reverse
osmosis, freezing, or biological treatment.  Table 9 lists the methodologies
currently in use or contemplated for use in treating coal cleaning wastewaters.
While all of the techniques for control of suspended materials have found
application, there is no known evidence of attempts at application of tech-
niques such as ion exchange, reverse osmosis, or freezing for control of
dissolved materials.

                     Control of Suspended Materials

          Suspended solids may be removed from liquid streams by mechanical
dewatering methods, sedimentation, or flbtation.  Each of these methods
produces a solid material which may be processed further in the coal cleaning
plant, in the case of a coal-rich material, or disposed of.as solid waste.

Mechanical Dewatering

          Mechanical dewatering devices applicable for removing solid materials
from water include centrifuges  and various kinds of  filters.  A centrifuge is
a device which rapidly rotates  a solids-containing stream in order that
centrifugal force can separate  the solid  and  liquid  fractions.  Vacuum filters
are used in the dewatering  of fine coal products and fine refuse  from wastewater.
                                     813

-------
         TABLE 9.   CLASSIFICATION OF WATER TREATMENT
                   TECHNOLOGIES
    Control of                            Control of
Suspended Materials	Dissolved Materials
Mechanical Dewatering                 Neutralization
  Centrifuges                         Adsorption
  Cyclones                            Ion Exchange
  Screens                             Reverse Osmosis
  Filters                             Freezing
Sedimentation                         Biological Oxidation
  Settling Ponds
  Sedimentation Tanks (Thickeners)
  Inclined Plate Settlers
  Flocculation
Flotation
                             814

-------
Although a drum type of vacuum filter is available, the disk type has been
the traditional choice in coal cleaning plants.

Sedimentation

          Sedimentation processes allow suspended materials to settle to the
bottom of a vessel and incorporate means for continually removing settled
solids and supernatant liquor separately.  Systems classified under sedimen-
tation include settling ponds or lagoons and various configurations of
sedimentation tanks.
          Filtration and sedimentation can be improved by the addition of
flocculants.  Among commonly used additives are alum, lime, iron salts,
sulfuric acid, starches, and polymers.  Although polymers are the most
expensive, on a per unit basis, they are used in very small concentrations
and work very well.

                     Control of Dissolved Materials

          The most common pollution problem with dissolved substances in
wastewater is pH control.  For coal cleaning wastewater and drainage from
coal and refuse piles, the problem is usually acidity, so an alkaline additive
is needed; lime is the preferred reagent for this purpose.
                     SOLID WASTE CONTROL TECHNOLOGY

               Primary Problems with Refuse Disposal Areas

          The major problem areas associated with land disposal of coal
cleaning refuse are fugitive dust, fire potential, erosion, and leachate
generation.  Aesthetics and the ultimate use of the disposal area are generally
less difficult problems to solve.
          The refuse generated by a coal preparation plant contains considerable
quantities of fine particles, leading to potentially serious fugitive dust
problems.  Proper disposal site selection can be a partial solution to this
                                     815

-------
 problem.  The orientation of the valley with respect to prevailing winds
 should be considered.  A crusting agent may be employed to prevent water
 infiltration and fugitive dust from refuse piles.
           Because of the considerable amount of organic matter in coal
" preparation refuse, fire resulting from spontaneous combustion in the refuse
 banks is a matter of concern.   Compacting the refuse piles will minimize
 air circulation and reduce the likelihood of fire.   In addition, sealing
 the pile, either with an occasional soil covering or with a crusting agent,
 also may reduce the fire potential.
           Particle sizes are such that the refuse is particularly susceptible
 to erosion.   Diversion ditches to minimize flow of  water over the refuse
 surface, as well as siltation basins to capture eroded material, are essential.
 The supernatant liquid (leachate) from the siltation basin should be monitored
 for high pH, sulfate, calcium, total dissolved solids, and heavy metals before
 being discharged to the environment.  Treatment of  this liquid may be necessary.
           Because of the heavy metals concentrated  in coal refuse, the
 leachate from the refuse can be expected to be high in metal ions.  This is
 especially true if the leachate is acidic, as most  of the metallic minerals
 are quite soluble in acid.
           It is possible to minimize leachate production from a disposal
 facility by (1) diverting all  surface drainage, (2) applying a cover material
 to prevent infiltration of  rainfall, (3) grading to promote rapid runoff (but
 not so rapid as to create excessive erosion),  (4) minimizing the open
 (working) area, and (5) applying a vegetative cover upon completion of an
 area.  In mos.t cases, a naturally impermeable soil, or in some cases a
 synthetic liner,  is used to prevent infiltration of the leachate into the
 ground and eventually into  the groundwater.
           An underdrain system is needed to gather  the leachate and carry it
 to a leachate treatment system.   Leachate treatment will probably consist of
 lime neutralization and settling.   As well as  improving pH,  lime treatment
 will remove  large quantities of metal ions, which are relatively much less
 soluble at higher pH levels.   However,  additional physical or chemical treat-
 ment may be  required.
                                     816

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                          Fine Refuse Disposal

          Fine refuse is  considered to be refuse smaller than 28 mesh.  It
occurs as the thickener underflow and may contain 75 percent moisture.  There-
fore, handling of fine refuse is genera-Lly done hydraulically, by pumping
the slurry from the preparation plant to a disposal area.  Direct disposal
of the fine slurry into streams is no longer practiced.  Disposal of fine
refuse is now accomplished by slurry impoundment or dewatering, allowing
the resulting fine solids to be disposed of together with the coarse refuse.
                         POLLUTION CONTROL COSTS
                      ASSOCIATED WITH COAL CLEANING

          With the use of proper control methods and "good housekeeping",
environmental control is technically feasible for most waste streams emanating
from coal preparation plants.  However, the question is:  "What is practical
and to what extent does one have to go to provide an acceptable discharge to
the environment?"  Moreover, the costs of pollution control for coal preparation
(including recovery and reclamation) are frequently so great that only a
minimal effort is made to control pollution.
          In the following discussion, the costs for various types of
pollution control equipment and techniques have been summarized from Battelle
cost estimates and from other sources.

                     Air Pollution Control Equipment

          Table 10 shows the installed capital costs and operating costs
for air pollution control equipment for a hypothetical 1000 tons/hr coal
cleaning plant with the following levels of treatment.
          (1)  Crushing and Sizing
          (2)  Medium Size Coal Beneficiation With Air Tables
          (3)  Fine Size Coal Beneficiation With Thermal Drying
          For the first two types of treatment, more than one particulate
control device is applicable; in this case, cost estimates are shown for
                                    817

-------
                   TABLE 10.  ESTIMATED  COSTS  OF AIR POLLUTION  CONTROL  EQUIPMENT  FOR TWO TYPES
                              OF  1000 TPH  COAL CLEANING PLANTS(7,8,9)
        Plant
       Type(a
   Emission
     Applicable
 Control Equipment
  Installed Cost of
  Control  Equipment,
Dollars (1977)/ton/hr
Annual Operating
 Cost  of  Control
  Equipment(b),
    cents/ton
         1,2
Dust from
crushing and
sizing operation
oo
(->
oo
Dust from air
tables operating
on medium-size
coal
                   Thermal  dryer
                   off-gas
Dust enclosures
with dry bag
collectors

Dust enclosures with
high-efficiency wet
scrubbers

Primary cyclones
followed by dry
bag collectors

Primary cyclones
followed by high-
efficiency wet
scrubbers

Primary cyclones with
high-efficiency wet
scrubbers

Primary cyclones with
high-efficiency wet
scrubbers followed by
limestone scrubbing
          36
                                                                            20
                                                                           360
                                                                           200
                                                        250
                                                                          9250
       0.1
                                                                                0.2
                                 2.8
                                                                                9.7
                                12.2
                                                                               93.8
       (a)   Both plant  types  1  and  2  include  crushing  and  sizing  operations  and  coarse  (3  x  3/8  inch)  coal
            beneficiation by  jigs or  dense  medium vessels.   Plant type  1  includes pneumatic  tables for
            medium (3/8 inch  x  28 M)  and fine (28 M x  0) coal  beneficiation.   Plant  type 2 includes wet
            concentrating tables or dense medium cyclones  for  medium size coal beneficiation and hydrocyclones
            or  froth  flotation  for  fine  coal  beneficiation.
       (b)   Excludes  capitalization,  depreciation,  and interest.   Based on 180 (2-shift) days.

-------
 each type of treatment.   For the third type,  an additional cost was  included
 to account for flue gas  desulfurization on the thermal  dryer.   Limestone
 scrubbing was selected as the basis  for the cost estimate  because  of its
 more developed state.
           To more effectively assess the environmental  problems associated
 with disposing of the  collected  particulate wastes  generated  from  the
 crushing and sizing operations,  information should  be obtained  on  the
 characteristics of the wastes.   Knowledge of  the composition, leachability
 and chemical activity  of the wastes  would be  helpful in determining  any
 potential environmental  complications  with their disposal  as well  as alter-
 native  handling or disposal  procedures.
           The capital  and operating  cost information should be  better
 quantified to determine  more accurately pollution control  costs for  different
 types of plants.   In addition to more  accurate modular  costs, information
 is  also  needed  on instrumentation and  control, installation, power,  and
 maintenance  costs.

                     Water  Pollution  Control Equipment

           Table  11  shows  the  estimated  costs  of water pollution control
 equipment  for a  hypothetical  1000 tons/hr  coal cleaning plant with the
 following  specified  processing configurations:
           (1)   Crushing and sizing with dry screening and wet beneficiation
           (2)  Medium  size coal beneficiation with wet  screening and wet
               beneficiation.
           In generating the treatment costs,  it has been assumed that all
water treatment  is performed  to satisfy environmental constraints.   Actually,
much of  the treatment,  particularly  the dewatering treatment,  is necessary
 for operation of  the coal cleaning processes.   Thus, a portion of the costs
cited may be attributed to process requirements rather than environmental
requirements.  Furthermore, since the use of closed water circuitry is a
viable alternative to treatment and release of wastewater,  the water most
likely to be treated for  release to the. environment is runoff  and leachate
from coal storage and coal refuse piles.
                                    819

-------
                            TABLE 11.  ESTIMATED COSTS OF WATER POLLUTION CONTROL EQUIPMENT FOR
                                       SELECTED 1000 TPH COAL CLEANING PLANTS <10>
                                                                                                              Annual Operating
                                                                                      Installed Cost of           ~~Cost of
                                                Quantity,   Applicable Control       Control Equipment,    Control Equipment^
     Plant Type           Effluent                 gpm           Equipment              1977 dollars           1977 cents/ton'


     Crushing and         Process Water           3,450
     Sizing with          Flow-
     Dry Screening         Suspended Solids                  Radial flow thickener         345,000                 0.8
     and Wet                                                 lagoon, or                    108,000                 0.6
     Beneficiation                                           froth flotation               33,000               0.7-1.4
                           Dissolved                        Absorption-activated         l,700,000^a^              2.0
                           Solids                            carbon treatment
00
K)
     Crushing and         Process Water           7,650
     Sizing with          Flow-
Wet Screening
and Wet
Beneficiation



Fine Size Coal
Beneficiation
with Hydroclones
and Thermal
Drying
Suspended Solids





Process Water
Flow-
Suspended Solids


Mechanical dewatering-
hydroclones ,
micros creens, or
pressure filters
Thickener or
lagoon
9,250

Radial flow thickener
or lagoon


150,000
230,000
310,000
510,000
160,000


560,000
180,000


1.4
1.0
1.8
1.2
0.8


1.3
0.9

     (a)  Adsorption is not  presently used to treat coal cleaning process water,  and would not be necessary for
          treating the recirculating process water for any plant with a closed water circuit.

     (b)  Including depreciation and Interest on capital.

-------
          Much of the information presented is based on preliminary infor-
mation and estimates.  Contact with plant operators and vendors can aid
in acquisition of much more detailed capital and operating costs of control
equipment, especially as applied to the specific plant types.   More infor-
mation should be acquired on disposal of waste streams produced by ion
exchange and reverse osmosis treatments.  The data acquisition task even-
tually will provide detailed information on performance of control equipment
and actual pollutant concentrations in raw and treated water streams.  In
addition, the proportions of treated and untreated process water will be
discovered, making it possible to estimate real pollution control costs more
accurately.

                  Solid Waste Disposal and Reclamation

          The U.S. Bureau of Mines has studied the costs to the coal industry
of refuse disposal and reclamation for nine coal waste disposal projects.
These cost estimates are the basis for the costs shown in Table 12.  Waste
disposal costs are divided into those for transportation of the waste to the
disposal plant, spreading and compacting the wastes, soil covering and
planting of the disposal area, and capital costs for land, site preparation,
and operating equipment.  These costs did not include the cost of installing
or operating leachate collection or surface drainage collection and treatment
facilities, which will increase the total costs.

     TABLE 12.   ESTIMATED COSTS OF SOLID WASTE DISPOSAL FOR TYPICAL
                1000 TPH COAL CLEANING PLANT (H)
   Transportation of refuse to disposal site          $0.36/ton refuse
   Spreading and compaction of refuse                  0.17/ton refuse
   Soil covering and planting                          0.05/ton refuse
   Capital cost                                        0.04/ton refuse
                                                      $0.62/ton refuse
                                     821

-------
          The costs are presented here in  terns of dollars per ton of refuse.
This total compares with results of a study done by the University of Kentucky
showing coal refuse disposal costs in the  range of $0.50 to $1.00 per ton.
Based on a typical coal cleaning plant, such as the concentrating table and
hydrocyclone plant shown earlier, with a rejection of 26 percent of raw coal
input, the total cost shown here amounts to $0.22 per ton of clean coal or
$0.16 per ton of raw coal input.
                             ACKNOWLEDGMENT

          The authors wish to acknowledge the contributions made by other
Battelle staff members to this paper through their studies in these and
related areas.  These staff members include S. Min, W. E. Ballantyne, and
D. W. Neuendorf.  Acknowledgment also is made of the support provided by the
U.S. Environmental Protection Agency under Contract No. 68-02-2163 which made
this work possible.  The Project Officer is Mr. James D. Kilgroe, Industrial
Environmental Research Laboratory, Research Triangle Park, North Carolina  27711,
                                   822

-------
                                REFERENCES
 (1)   Kurth,  D.  I.,  Sundae,  L.  S.,  and Schultz,  C.  W.,  "Dust Generation and
      Comminution of Coal",  U.S.  Bureau of Mines,  RI 8068 (1975).

 (2)   Handbook of Environmental Control,  Volume  I,  Air  Pollution,  Chemical
      Rubber  Company,  Cleveland (1972), p 295.

 (3)   U.S.  EPA,  "Background  Information for Standards of Performance:   Coal
      Preparation Plants,  Volume 1,  Proposed Standards", EPA 450/2-74-02/a
      (October 1974).

 (4)   Nichols, C. R.,  "Development  Document for  Effluent Limitations
      Guidelines and New Source Performance Standards for the Steam Electric
      Power Generating Point Source Category", U.S. Environmental  Protection
      Agency,  Washington,  D.C.  (1974).

 (5)   Vekris,  S. L., "Dispersion of Coal Particles from Storage. Piles",
      Ontario Hydro  Research Quarterly, 23^ (2),  pp 11-16 (1971).

 (6)   Gluskoter, H.  J., Ruch, R.  R., Miller, W.  G., Cahill,  R. A., Dreher,
      G.  B.,  and Kuhn, J.  K., "Trace Elements in Coal", EPA-600/7-77-064,
      Industrial Environmental Research Laboratory, U.S. Environmental
      Protection Agency, Research Triangle Park, North  Carolina (1977),
      163 pp.

 (7)   Lund, Herbert  F., Industrial  Pollution Control Handbook, McGraw-Hill,
      New York,  New  York (1971).

 (8)   Air Pollution  Manual.  Part II, American Industrial Hygiene Association,
      Detroit, Michigan (1968).

 (9)   Zimmerman, 0.  T., "Dust Collectors", Cost  Engineering, January 1972,
      pp  4-5.

(10)   Coal Preparation, edited by J. W. Leonard, et al., Third Edition, AIME,
      New York,  New  York (1968).

(11)   U.S.  Bureau of Mines,  "Methods and Costs of Coal Refuse Disposal and
      Reclamation",  1C 8576  (1973).

(12)   Rose, J. G., et al., "Composition and Properties of Refuse from
      Kentucky Coal  Preparation Plants", Proceedings of the Fifth Mineral
      Waste Utilization Symposium,  Chicago, Illinois, U.S. Bureau of Mines
      (April  1976).
                                      823

-------
             CHARACTERIZATION OF PREPARATION PLANT WASTEWATERS

               K. B. Randolph, L. B. Kay, and R. C. Smith, Jr.
                                Versar, Inc.
                           Springfield, Virginia
                                  ABSTRACT
     During the Environmental Protection Agency's review of guidelines for
the coal mining industry, eighteen preparation plants and ancillary areas
were screened for priority pollutants as well as the classical ones.  Of
these eighteen, four were examined more extensively in the "verification"
phase of the review.  This paper discusses the findings of those studies.
The compositions found in the screening phase are compared with those from
the verification phase.  Differences in composition among preparation plants
are compared on the basis of region, rank of coal, type of mining,  cleaning
process, and plant age.  By way of presenting these results,  sampling and
analysis procedures are discussed.
                                       824

-------
INTRODUCTION
     In December of 1976, the Effluent Guidelines Division of the Environ-
mental Protection Agency ccranissioned a study by Versar to provide technical
assistance in reviewing the best available technology (BAT) for wastewater
pollutants from the coal mining point source category.  This review resulted
from a federal court decision of June 1, 1976, which required the Agency to
perform sampling and analysis of wastewaters from 21 industries for certain
pollutants as well as classical water quality parameters.  The above pollu-
tants represent 65 compounds and classes of compounds which the EPA had
failed to take into consideration in previous effluent guidelines studies.
The process of delineating specific compounds frcm these classes resulted
in a list of 129 organic compounds and metals which are tabulated in
Appendix A and have become known as the priority pollutants.
     The screening sampling phase of this study was conducted during April,
May and June of 1977.  Eighteen preparation plants, associated with coal
mines were visited and wastewater samples were obtained from 7 of these
facilities.  In addition, wastewater samples were obtained frcm such ancillary
areas as refuse piles from 5 of these facilities.
     Four coal preparation facilities currently are being examined more
.extensively during the verification phase of this review.  Verification
sampling was to have been conducted this past spring.  Hawever, the recent
strike by the United Mine Wbrkers of America delayed the scheduling of this
phase of the program*
     In the interim, Versar has been conducting a mine drainage treat-ability
study at the Environmental Protection Agency Crown Mine Drainage Control
Field Site facility, located near Morgantown, West Virginia.  The study is
designed to identify and assess control technologies to remove organic
priority pollutants found in coal mine drainage and preparation plant waste-
waters.  Preliminary findings  from this study are also discussed in this
paper.
                                      825

-------
DISCUSSIONS CF METHODOLOGY
Site Selection
     Twenty-three coal mining facilities were selected for screening sampling
by Versar in conjunction with the. Environmental Protection Agency and the
Vfeter Quality Conmittee of the National Coal Association.  Facilities were
selected on the basis of region, rank of coal, type of mining and cleaning
process.  Versar conducted the sampling at 22 mines.  The remaining facility
was sampled by the Calspan Corporation,  tail Goldberg was the first project
officer on this program, succeeded by Al Galli, who, in turn, was followed by
the current project officer, Ron Kirby.  This work was under the direction of
Bill Telliard, Chief, Energy and Mining Branch, Effluent Guidelines Division,
EPA, under contracts 68-01-3273, Task 15 and 68-01-4762.
Outfall Identification
     Raw wastewater and treated effluents were sampled at each facility,
where mining or preparation process design permitted.  Continuous discharges
were sampled by time proportional composite.  Where discharges or flows were
intermittent, because of the dry weather conditions of the spring of 1977,
grab samples were taken and composited, where possible.
Sampling Methods
     Continuous discharges were composite sampled for 24 hours using an "Isco"
sampler.*  Intermittent discharges were grab composited.  Composite samples
were divided into 1 liter aliquots for analyses for metals, organics, pesticides,
solids, asbestos, phenols, TOC and COD.  Separate samples were collected for
volatile organics and cyanide analyses.  All samples were stored, preserved
and shipped according to "Satpling and Analysis Procedures for Screening of
industrial Effluents for Priority Pollutants," USEPA, EMSL, Cincinnati, Ohio
45268, April 1977.  The pH was measured using an Orion or Cole Palmer pH
meter.  Flow rates were determined by methods appropriate to the specific
situation.
Analytical Methods
     Analyses were conducted by Versar, the EPA Region V Analytical laboratory
and two EPA analytical contractors.  Versar conducted the analyses for the
* TSCO - instrumentation Specialties  Company,  Uncoln,  Nebraska
                                      -o2-b

-------
 classical water quality parameters as well as for phenols,  cyanides,
 pesticides, PCBs and four priority metals: antimony,  arsenic,  selenium and
 thallium.  The remaining metals were analyzed by the  EPA Region V Analytical
 laboratory in Chicago.   The Carborundum Corporation and Gulf South Research,
 Inc.,  analyzed the samples for organics.
     All analyses were  conducted according to EPA analytical protocols.
 Metals were analyzed by plasma source atonic absorption spectrophotcmetry.
 Organic compounds were  identified using gas chromatography/mass spectroscopy
 (GC/MS).
 RESULTS AND DISCUSSION
     The results of the screening phase of this  program are presented  in
 two parts:  metals and organics.   These parts are further broken down into
 waters from preparation plants and water fron associated areas,  i.e.,  refuse
 and storage piles.   These results are further subdivided and regrouped by
 the mine type (surface  or deep),  the mine water  (acid or alkaline), type of
 processing  (water only,  heavy  media and flotation), geographical location
 and water treatment process.   These results are  discussed as they are  pre-
 sented.
     Since  these are the results  of the screening phase,  they are somewhat
 preliminary in nature in that  they have not been verified by more extensive
 sampling.   Furthermore,  the coal  mining industry was  the first  to be sampled
 under  the BAT review, and thus was  the first industry to be sampled for many
 of  these  parameters.  This is  especially important in considering the  organic
 priority  pollutants.
     In the following, the terms  acid preparation plant  and alkaline prepara-
 tion plant  are used.  These refer to  the type of drainage associated with
 the mine  that supplies the coal to  the plant and not necessarily to the
water  frcm  the plant  itself.   However, preparation plants in the acid group
do have generally lower pH waters than those in  the alkaline group - 3.8 vs.
 7.0.
                                     827

-------
 Priority Metals
      Table  1  shows  that virtually all priority metals (except silver) were
 found in the  wastewaters  from acid plants.   This nay be contrasted with the
 results  for alkaline plants shown in Table 2.  In  the acid case,  three
 metals were found in all  streams,  and four metals  were  found  in eight of the
 nine streams.  However, in the alkaline case,  no metal  was found  in all
 streams, and  only the  "ubiquitous" iron was  found  in all but  one  stream.
 Only for one metal, chronium,  was  the highest  concentration found in an
 alkaline plant.  Clearly  then, the waters associated with  preparation plants
 processing  coal from alkaline mines are "cleaner"  than  waters from those
 plants cleaning coal from acid mines.
      The kind of stream that produces the highest  concentration of these
 metals is shown in Table  3 for each priority metal.   Note  that the high
 concentrations occur in three streams out of the nine satpled.  These are:
      (1)  A refuse slurry from an anthracite breaker,
      (2)  A grab sample taken fron a drag tank,
      (3)  A very acid,  old, strip pit used for a recycle pond.
      In two of these cases samples were taken of the same waters after treat-
 ment.   These treated values are shown in Table 4  along with the percent
 reduction in concentration.
      In the first case, the anthracite  breaker, the treatment consisted of a
 series of three settling ponds.  The  first two were divided by a baffle dan
 constructed of refuse.   The second of these emptied, by means  of an asbestos
 pipe, into  a third pond.
     The  second case, the  drag tank water,  occnbines with other circuits in
 the prep  plant and flows to a  slurry pond  from where it is  recycle to the
 process.
     The  third case, the very  acid pond, is unique.  This was  a non-
 discharging  pond which  was an old acid strip  pit.   This  water  was  so acid,
 pH  2.9, that it had to  be  neutralized before  reuse.  This was  accomplished
 by  injecting anhydrous  arnnonia  in the recycle line.  This line could not be
 sampled readily to assess  the effectiveness of the  treatment,  however, the
treatment may account for  the high levels of  nickel and  zinc as the ammonium

                                     828

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                                   TABLE 1

        ACID PREPARATION PLANTS, PRIORITY METALS FREQUENCY AND RANGE
Metal
Antimony
Arsenic
Beryllium
Cadmium
Chronium
Copper
Iron*
Lead
Manganese*
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Cyanides
Phenols
Frequency
(9 Streams)
8
9
2
1
5
8
9
4
9
6
3
8
0
6
8
0
1
Range,
Low
0.001
0.002
0.007
	
0.036
0.03
0.098
0.067
0.025
0.0003
0.095
0.005
	
0.001
0.039
	
___
(mg/1)
High
0.021
1.23
0.02
0.032
0.44
0.72
3,000
0.76
39
0.0075
0.92
0.41
	
0.070
1.37
	
0.025
Detectability
Limit, (mg/1)
0.001
0.001
0.002
0.02
0.024
0.004
0.02
0.06
0.01
0.0001
0.05
0.006
0.025
0.001
0.025
0.005
0.02
* Not on the priority pollutant list but one on which the industry
  is regulated
                                     829

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                                   TABLE 2
       ALKALINE PREPARATION PLANTS, PRIORITY METALS FREQUENCY AND RANGE
Metal
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Iron*
Lead
Manganese*
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Cyanides
Phenols
Frequency
(10 Streams
5
7
0
0
5
3
9
0
8
6
1
4
0
4
8
0
1
                                      Range, (mg/1)
                                      low      High.
                                      0.002
                                      0.002
                                      0.001
                                      0.026
0.007
0.045
                                      0.033    2.0
                                      0.005    0.27
                                      0.161    200

                                      0.024    2.0
                                      0.0004   0.002
                                       	     0.53
                                      0.002    0.05
0.004
1.0

0.035
Detectability
Limits, (mg/1)
    0.001
    0.001
    0.002
    0.02
    0.024
    0.004
    0.02
    0.06
    0.01
    0.0001
    0.05
    0.001
    0.025
    0.001
    0.025
    0.005
    0.02
*  Not on the priority pollutant list, but one on which the industry
   is regulated
                                     830

-------
                       TABLE 3
SOURCE OF ACID PREPARATION PLANT MAXIMUM CCNCENTRATIONS
    Maximum
Metai uoncenrra'cion
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Cyanides
Phenols
0.02
1.23
0.02
0.032
0.44
0.72
3,000
0.76
39
0.0075
0.92
0.41
	
0.07
1.37
	
0.025
                       Stream Description
                       Prep plant drag tank, grab sample, total metal
                       Anthracite refuse slurry, total metal
                       Slurry to thickener grab sample
                       Very acid recycle pond  (pH 2.9), actually
                       an old strip pit
                       Drag tank, grab sample
                       Anthracite refuse slurry
                       Drag tank
                       Anthracite refuse slurry
                       Very acid recycle pond  (pH 2.9)
                       Anthracite refuse slurry
                       Very acid recycle pond
                       Anthracite refuse slurry
                       None detected
                       Drag tank grab sample
                       Very acid recycle pond
                       None detected
                       Anthracite refuse slurry
                            831

-------
                                   TABLE 4
Metal
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Iron
lead
Manganese
Mercury
Nickel
Selenium
Thallium
Zinc
iar.CMflt.-r CP ISEMMENT ON HIQ
Concentration, (mg/1)
Raw
0.021
1.23
0.02
0.032
0.44
0.72
3,000
0.76
39
0.0075
0.92
0.41
0.070
1.37
Treated
0.001
0.004
(a)
(b)
0.036
0.044
0.183
<0.06
(b)
0.0016
(b)
<0.006
<0.001
(b)
Reduction
(percent)
   95.4
   99.7
   91.8
   93.9
   99.994
  >99.9

   78.7

 >98.5
 >98.6
(a)  Treated water not sampled
(b)  Closed circuit,  pond does not discharge
                                     832

-------
complexes.   (The latter has not been verified by any analyses and is offered
only as a possible explanation.)
     The extraordinary effectiveness of settling in these two cases leads to
the conclusion that the priority metals are associated primarily with the
solid phase in these slurries.  Since the analyses performed were for total
metals, as is called for in the protocol, this is not surprising.  This also
explains why most of the high values for metals were found in slurry streams.
     Further breakdowns of these results by type of process, geographical
location, and type of mining are shown in Tables 5, 6 and 7.  The upshot
of these tabulations is that the single most iitportant difference is whether
the coal comes from an acid or alkaline region.  The greater frequency of
priority metals and the higher concentrations in Iforthem Appalachia is
because this is an acid area.
Organic Compounds in Preparation Plant Waters
     The organic priority pollutants found in waters from preparation plants
and associated areas are shown in Table 8.  Fourteen compounds on the
priority pollutant list were found above detectable limits.  Some of these
were found frequently and some only once.
     These results should be viewed skeptically since the coal mining industry
was the first industry to be screened for the priority pollutants.  Many
lessons were learned in the process, and these are being applied to the
treatability studies and the verification sampling underway at present.
They have been a most useful guide.
     The prevalence of organic pollutants was examined from the  standpoint
of industry  characteristics.  These were: type of mine drainage  (acid or
alkaline), type of mining  (surface or deep), type of process  (water only,
heavy media  and flotation), and geographical location  (Central,  Northern
Appalachia,  Southern Appalachia).  The data base was not sufficient to
categorize the industry by ooal seam or coal rank.
     No clear pattern was discernible in these classifications except,
perhaps, that preparation plants and associated areas in the  Central Region
have a more  frequent occurrence of organic  pollutants.

                                      833

-------
                                   TABLE 5

        COMPARISON OF PREPARATION PLANT WASTEJ&TERS BY PROCESS TYPE
                    HEAVY MEDIA AM)
                    FROTH FLOTATION
WATER ONLY
Metal
Antimony
Arsenic
Beryllium
Cadmium
Chronium
'Copper
Iron*
Lead
Manganese*
Mercury
Nickel
Selenium
Silver
thallium
Zinc
Cyanides
Phenols
Frequency Range ftng/1) Frequency Range
(10 Streams) Lew High (8 Streams) Low
4
7
0
0
3
5
10
1
10
6
2
2
0
3
7
0
2
0.001
0.002
	
—
0.024
0.004
0.098
	
0.01
0.0001
0.05
0.001
0.001
0.025
	
0.02
0.003
1.23
	 .
	
2.0
0.72
210.0
0.76
20.0
0.0075
0.53
0.41
0.009
1.0
	
0.035
5
8
1
1
7
6
7
3
8
5
2
4
0
4
8
0
0
0.001
0.005
	
	
0.033
0.044
0.02
0.06
0.025
0.0001
0.05
0.003
0.001
0.031
___
___
tog/1)
High
0.021
0.17
0.007
0.032
0.44
0.21
3,000
0.167
39.0
0.0008
0.921
0.16
0.070
1.37
—
-,-.„
* Nat on the priority pollutant  list, but one on which the industry
  is regulated
                                    834

-------
                                        TABLE 6
              COMPARISON OF PREPARATION PLANTS AND ASSOCIATED AREAS BY REGION

Metal
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
oo Iron*
" Lead
Manganese*
Mercury
Nickel
Selenium
Silver
thallium
Zinc
Cyanide
Phenols
N. Appalachian and
Ohio Region

Frequency
(10 Streams)
6
10
1
0
6
9
10
4
10
7
4
8
0
5
9
0
1
Range
Low High
0.001 0.028
0.003 1.34
0.22
-
0.024 0.98
0.004 1.0
0.098 9000.
0.06 1.0
0.025 80.0
0.001 0.0075
0.05 10.0
0.005 0.45
_
0.001 0.07
0.025 30.0
_ _
0.025
S. Appalachian Region
Range
Frequency
(8 Streams)
8
0
0
1
2
8
0
7
7
1
6
0
2
3
0
3
Low
0.001
0.002
-
-
-
0.004
0.103
-
0.024
0.001
-
0.001
-
0.002
0.037
-
0.030
High
0.003
0.045
-
-
2.0
0.006
9.0
-
2.09
0.0048
0.53
0.004
-
0.003
0.168
-
0.035
Central Region
Range
Frequency Low
(5 Streams)
5 0.002
5 0.005
1
1
3
2
4
1
4
4
1
3 0.003
0
1
5 0.029
0
0

High
0.007
0.028
0.007
0.032
0.115
0.056
7.63
0.167
39.0
0.0007
0.921
0.005
—
0.004
1.37
—

* Not on the priority pollutant list,  but one on which the industry is regulated

-------
                                  TABLE 7

               CQMPARISCN OF PREPARATION PLANTS BY TXPE OF MINING
                     Surface Mines
Deep Mines
Metal
Antimony
Arsenic
Eery Ilium
Cadmium
Chranium
Copper
Iron*
Lead
Manganese*
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Cyanides
Phenols
Frequency Range (mg/1)
(9 stream*! Low ^4"
7
9
1
1
6
6
8
3
9
7
4
3
0
3
8
0
1
0.001
0.002
—
	
0.024
0.004
0.02
0.06
0.046
0.0001
0.05
0.001
—
0.001
0.029
-_
___
0.021
1.23
0.007
0.032
2.0
0.72
3,000
0.76
39.0
0.0075
0.921
0.41
—
0.070
1.37
___
0.025
Frequency Range (mg/1)
(11 Streams) Low Hiqh
4
11
1
0
5
5
11
1
10
6
2
3
0
4
8
0
1
0.001
0.002
	
	
0.024
0.004
0.098
	
0.01
0.0001
0.05
0.001
	
0.001
0.025
	
___
0.008
0.17
0.02
	
2.0
0.27
200
0.067
6.32
0.0009
0.095
0.16
—
0.039
1.0
—
0.035
*  Ifot on the priority pollutant  list, but one on which the industry
   is regulated
                                     836

-------
                                  TABLE 8
              OCCURRENCE OF ORGANIC PRIORITY POLLUTANTS IN COAL
                   PREPARATION PLANTS AND ASSOCIATED AREAS
vxii^Uunu rZaCjU
itethylene chloride
chloroform
1 , 1 , 1 ,- trichloroethane
trana-dichloroethene
tetrachloroethene
trichlorofluoromethane
chlorobenzene
2,6-dinitrotoluene
benzene
toluene
ethylbenzene
anthraoane/phenanthrene*
diethyl phthalate
di-n-butyl. phthalate
bis(2-ethylhexyl) phthala.te
sncy UJ. streams;
21
17
5
7
7
2
1
1
9
11
1
1
2
4
11
                                                  Conoentraticn Range (yg/1)
                                                    Low            High

                                                    2.6           66,000
                                                    1.6              476
                                                    1.4                2
                                                    1.4               10
                                                    1.4               20
                                                   14                 22
                                                                      12
                                                                      30
                                                    0.3               48
                                                    0.3               30
                                                                      >0.2
                                                                      20
                                                  110                790
                                                  210                630
                                                   10              6,100
* Analytical method (GC/MS)  cannot distinguish between these two compounds.
                                     837

-------
                                       TABLE 9
                FREQUENCY  & RANGE OF ORGANIC PRIORITY POLLUTANTS  IN
                       PREP. PLANTS AND ASSOCIATED AREAS
COMPOUND
methylene chloride
chloroform
1,1,1-trichloroethane
trans -dichloroethene
tetrachloroethene
trichloroflinrcmsthane
chlorobenzene
2,6-dLnitrotoluene
benzene
toluene
ethylbenzene
anthracene/phenanthrenei
diethyl phthalate
di-n-butyl phthalate
bis (2-ethylhexyl)
     phthalate
FREQUENCY
Prep Plants
nt ft OTJ-L . mn \
114 streams;
14
13
4
5
6
1

1
5
6
1
1
2
3
9
Asaoc. Areas
CJ Streams)
7
4
1
2
1
1
1
0
4
5
0
0
0
1
2
CONCENTRATIGN RANC£ (UQ/D
Prep Plants.
Lew High
2.6 20,000
1.6 152
1.4 2
1.4 10
1.4 20
14

30
0.3 12
0.3 5.1
>0.2
20
110 790
270 630
13 1,200
Asaoc. Areas
Low High
348 66 ,000
19 476
1.7
1.7 1.0
1.2
22
12
- -
6.3 48
2.0 30
-
-
_
210
10 6,100
     *The analytical method (GC/toS)cannot distinguish between these two compounds.
                                          838

-------
                                                   TABLE 10
                                     FREQUENCE OF OEGANICS BY SUBCATEGOFY
oo
w
\o
Compound
methylene chloride
chloroform
1,1,1-txichloroethane
trans-dichloroethene
tetrachloroethene
benzene
toluene
di-ethyl phthalate
di-n-butyl phthalate
bis(2-ethylhexyl) phthalate

Octal Number
Nm±ier per Stream
TKPE CF MINING

Deep
(7 Streams)
7
7
3
4
2
2
2
2*
2*
5*
36
5.14

Surface
(7 Streams)
7
6
1
1
4
3
4
0
1
4
31
4.43

Central
(4)
4
4
2
2
3
3
3
1
2
4
28
7.00
GEOGRAPHICAL REGION

No. Appal.
(7)
7
6
1
2
2
1
2
1*
0*
3*
25
3.57

So. Appal.
(3)
3
3
1
1
1
1
1
0
1
2
14
4.67
TYPE DRAINAGE;

Acid
(8)
8
7
1
2
3
2
3
1*
1*
4*
32
4.00
Alka-
line
(6)
6
6
3
3
3
3
3
1
2
5
35
5.83
     *   Cnly six streams available because of loss of sample in shipment

-------
 Treatability Studies
      The prevalence of organic priority pollutants in coal mine drainage
 and preparation plant wastewaters formed the impetus for the treatability
 studies currently underway at the Environmental Protection Agency's  Crown
 Mine  Drainage Control Site near Morgantown,  West Virginia.   The objectives
 of this study are to:
      1. demonstrate the effectiveness of the treatment currently in  use
         (HPT)  for removal  of certain organic priority pollutants,  and
      2. determine the effectiveness  of,  including  costs,  additional
        treatments to further reduce organic pollutant concentrations.
      Objective one has been virtually attained,  and objective two  should be
 achieved by  the end of September.  Sane  preliminary results concerned with
 the effectiveness of  HPT will be  presented here.
      Without going into the details  or the rationale for selecting the
 compounds to study, the selected  priority pollutants are shown  in Table  11.
      In the  studies of acid mine  drainage, water was obtained from the mine
 that  had been the source of water for other  studies at Crown Field Site.
 However, this mine had been closed for sane  six  to seven months prior to this
 study.  During that time some changes in composition of the water  had
 occurred, but  the water remained  acid and ferruginous.  On. pumping the mine
 no organic pollutants  were found.  Consequently  the selected pollutants
 were  spiked  into  the water at the approximate concentrations shown in Table
 11.
      The spiked acid water was then  treated  by lime neutralization followed
 by aeration, flocculation, and settling  in that order.  The effect of this
 treatment on the  volatiles is shown  in Table 12.  As can be seen,  the
 removal of volatiles is quite complete.   This reduction could be accounted
 for primarily by  the aeration step.
     To determine if aeration was causing an air pollution  problem or a
hazard to personnel in the plant, the air over the  aerator  (~6  ft. above
the water's surface) was monitored using a "Sipin"* pump.  Analyses of the
* Sipin - Anatole J. Sipin Company, 425 Park Avenue, South, New York,
          New York 10016
                                    840

-------
                                 TABLE 11
            SPIKEN3 CONCENTRATIONS OF SELECTED OK3ANIC POLLUTANTS
                            IN ACID MINE DRAINAGE
Conpound                              Concentration (yg/1)
benzene                                         55
toluene                                         35
methylene chloride                             250
chlorofbm                                     250
trans-^chloroethene                            10
l,lfl-trichloroethane                           10
tetrachloroethene                               30
bis(2-ethylhexyl) phthalate                 10,000
di-n-butyl phthalate                         1,400

-------
                                   TABLE 12
                    EFFECTIVENESS OF VOLATILE ORGANIC REMOVAL
""^^^-^^..^StaMam
Parameter ^"'^'^^-'^^^..^^^
methylene chloride
trana-dichloroethene
chloroform
1,1, 1-trichloroethane
benzene
tetrachloroethene
toluene
Feed
(rag)
87,24
3.48
87.24
3.48
19.53
10.48
12.23
Average
Effluent

-------
 samples thus obtained revealed very little in the  way of pollutants in the
 air,  as is seen in Table 13.   At no time did any concentration even approach
 the eight hour TLV.
      The effect of BPT on the two phthalate esters has not been  assessed as
 yet.   A conplication developed in reducing the data when a discrepancy in
 solubilities became evident,  i.e., the solubilities found in OIMTADS for these
 compounds are three orders of magnitude too high.
      In addition to acid drainage, alkaline drainage  is under  study too.
 The source of water for this  is a creek that runs  through Crown  Field Site,
 Indian Creek.   This creek has a pH of about 7.5 to 7.8,  and the  total sus-
 pended solids varies fron about 10 mg/1 to 300 mg/1 depending  on rainfall.
 This  water is pumped to the plant and spiked with  the organics.  However,
 in  the light of the new solubility data,  the composition was changed so that
 the phthalate concentrations  were reduced to 450 yg/1 each.
      This alkaline water received BPT treatment consisting of  settling in the
 clarifier.   In addition,  several runs were made where the spiked creek water
 received aeration before going to the clarifier.
      Preliminary work-ups of  the data show that aeration was as  effective
 at  removing volatiles as in the case  of acid water.   The results so  far on
 settling only in a clarifier  indicate that about 65 to 75 percent of the
 volatiles are  removed.
     Analyses  of the phthalates are not complete enough  at this  time to
 assess any effect of BPT.
     At  this writing, experiments  are going on with reduction of priority
metals in alkaline water, on ozonation to remove organics, and on carbon
 adsorption  to  remove organics.  Once  these studies are completed, a more
 exhaustive discussion of the treatability of coal mine drainage  and prepa-
 ration plant wastewater will be published.  Furthermore, this will have
 the back-up of the verification phase of the sampling study.  At that stage
an assessment of  loads to the environment can be made with some certainty,
and the economic  impact of any  treatment can be determined.
                                     843

-------
                                              TABLE 13
                                       AIR SM4PLES (Sipin Pimp)
                    Average Daily Ctganic Ooncsentrations (PPM) Period 5/23 - 6/5/78
Sample
location
Plant Aerator
Plant Clarifier
Chemistry
Laboratory
(Jim Kennedy)
Office -
Receptionist Desk
Control -
Bathroom in
Back Office
Threshold Limit1
Values Time-
Weighted Average
(S^iour workday)
1,2-trans
dichloro- chloroform
ethene
It) 0.126
ND 0.016
ND 0.021
0.071 0.024
0.067 ND
200 25
1 these TLV's represent the time-weighted average
workweek, to which normal Iv all workers mav be i
1,1,1-
txichloro-
ethane
0.007
0.021
0.010
0.012
0.009
10

Teneatedlv en
tetra-
benzene chloro—
ethylene
0.021 0.031
0.013 0.066
0.024 0.038
0.009 0.054
0.010 0.023
1.0 100
i for a normal 8-hour workday
aosed, day after day. without
toluene
0.073
0.053
0.018
0.045
0.021
100
or 40-hour
adverse effect.
ND = Not Detectable

-------
        APPENDIX A




LIST OF PRIORITY POLLUTANTS
             845

-------
                    Prioritv Pollutants
acer.apthene
acrolein
acrylonitrile
benzene
bensidene
carbon tetrachloride  (tetrachloro-
 raethane)
chlorobenzene
1,2,4-trichlorobenzene
hexachlorobenzene
1,2-dichloroethane
1,lf1-trichloroethane
hexachlorocthane
1,1-dichloroethane
1,1,2-trichloroethane
1,1,2,2-tetrachloroethane
chloroethane
bis(chloronethyl)ether
bis(2-chloroethyl) ether
2-chloroethyl vin^l ether  (nixed)
2-chloronapthalenb
2,4,6-trichlorophenol
parachlorometa cresol
chloroform (trichlormethane)
2-chlorophenol
If 2-dichloroben2ene
1, 3-dichlorobenzene
1,4-rtichlorobenzene
3,3l -fiichlorobenzidir.e
1,1-dichloroethylene
2,4-dichlorophenol
1,2-dichloronropane
1,2-dichloropronylene (1,3-cl.tchloro-
 propene)
2,4-dineth«lphenol
2,4-dinitrotoluene
2,6-dinitrotoluene
1, S-cliphejiylhyrirasine
ethylbenzene
fluoranthene
4-chloroohenyl phen^'l ether
4-brcnoohenyl phenyl  ether
bis ( 2-chloroiaor5ropyl )  ether
bis ( 2-chloroetho::") " methane
nethylenc chloride  (dichloro-
 nethane)
nethyl chloride  (chlorcne thane)
methyl bronide  (brononethane)
br onofom ( tr .D^r ononethane )
clichlorobrmonethnne
tr5.chlorof luoronethane
dichloroclifluoronethane
chlorodibrononethane
hexachlorocyclor>entadiene
isophorone
2 -n i tr or>heno 1
4 -n i tr onhenol
4 , 6-dinitro-o-crascl
7 J-n i trosocline thylaninc
N-n i tro sodiphenyl anine
>7-nitrosocli-n-iron«lanire
pentachlorophenol
phenol
bis (2-eth"lh«cyl) phthalate
but^'l bensyl phthalnte
di-n-hutyl nhthalate
di-n-oct-'l phthal«te
cl iethy 1 nhtfinl n to
dineth^l* phth?».late
Ixsnzo (a) anthracene  ( 1 , 2-N».n
benrto (n) pyrene ( 3 , A-
 pyrene)
3 , "^-benr.
benno (!') f lnoranthenn
 (11 ,12-benso*
chrvsene
acena^hth^l ere
                               846

-------
anthracene
benzo (ghi) perylene (1 , 3.2-ben-
 zoperylone)
fluorenc
phenantl irene
dibenso (a r h) anthracene (1 , 2 , £ , f
 dibensantliraceiie)
indano ( 1 , 2 , 3-c«l)  pyreno
 (2 , 3-o-plienylenepi»rene)
pyrene
tetrachloroethylene
toluene
trichloroethylene
vinyl chloride  (chloroethylene)
ale* r in
dieltirin
chlordane
4 , 4l -DT?
a-enclosulfan-Alpha
L-endosulfan-Beta
enuosulfan  sulfnte
endrin
enurin  aldehyde
heptaclilor
heptachlor  epo::ide
a-DHC-Aloha
b-BIIC-Beta
r-BHC- (lindane) -r.anma
g-DHC-Delta
PCB-1242  (Arochlor 1242)
PCB-1254  (Arochlor 1254)
          (Arochlor
PCB-1232  (ArocMor
?*cr,-12/in  (Arochlor
PCB-1260  (Arochlor
rcn-niG  (Aroohlor
to::aphone
antir^ony  (total)
arsenic  (total)
asbestos  (fibrous)
beryllinn  (total)
cadfdun  (total)
cluroniun  (total)
copper  (total)
cyanide  (total)
leatl  (tct.-\l)
nercur»'  (total)
nickel  (total)
neleniun  (total)
iiilver  (total)
tlialliun  (tot».l)
zinc  (total)
122?.)
1232)
                              847

-------
     APPENDIX B
ANALYTICAL RESULTS
CLASSICS AND METALS
      848

-------
Prep Plant
Drag TS/Jc
few Water
1bt*1 	 . 	 7,800
total Sk-^*tod Solids 	 ^
total volatile Solids 	
Volatile Suspended Solids — j-^j 	
cm 	
-== 	 	 	 — 	 1.130
(Slurry Fond
JEfflumt
I 1,100
7.4
j 150
Prep. Plant
Raw Kal/?r
38,000
37,000
28,000
3.6 j 28,000
20.6 14,700
j 3.2 1.100
— : 	 	 	 - 6.78 I 8.20 4.2
_J= 	 i
MOMS (HA) ~~300T» 	 L 0 099 	
Ucsrim 	 — 	 r """.' 	
	 	 ' 0.021
Antiacny
— 	 ~* - 0.065
Arsenic .._
Baziui 	 	 	
	 	 	 	 < 0.02
Berylliw 	
	 < O.ObO
CMfcdUB * Q"*°
	 • 268
— — — — — 	 0.44
,^J1(" < 0.10
, 	 6.21
Cbpper
iron J000-"
Lead 'O-60
HUT*-*— *"**
t| a |IU ' 0.12
0.03 Q
0.183 ,
0.067 j
55.9
210
0
.72

.76
8.0
Sot?- -Q
JVyid
240
11.8
220
2.4
27.2
9.2
4.4

1.76
<0.001 J
0.004 j
0.149 J
<0.002
0.014
<0.02
26.5
<0.024 '
0.1 Id
0.044
0.803
<0.06
10.3
°-025 20JO 3.870
<0.0001 . 0
0.03
< 0.05
0.012
< 0.025
44.5
0
<0
0075J 0.0016
16 1 <0.01
1.5
0.41
<0.25
13.
< 0.001 0
< 0.099 , <0
< 0.01 j o
< 0.099 , <0.
< 0.01 <0.
0.039 ' 0.
0
009
99
12
99
1
48
< 0.005 , 
-------
CLASSICAL PARAtOEBS ta/1)
Ibfcal Solids
\ Total Suspended Solids
total Volatile Solids
Volatile Suspended Solids
ODD
. TOC\
CB '
M2rALS tug/1)
Ali-4num
Antuccny
Arsenic \
Barium .v
BexvUiin A
Boron '
Cadnium '
, Calciua Y
\ji Chrcnium \
f"' -Cobalt . \
Dapper \
..Iron '
Lead ''•
Magnesium
Manganese
Mercury
fblybderan
Nickel
SeleniiD
Silver
Sodium
Uiallim'
Tin
Titanium
Vonadiun
Yttrium
Zinc
Cyanide
Phenol

PRH> PLANT
RECYCLE
POD
2200
8.0
220
1.6
11.6
<1.0
6.4

<0.099
0.004
0.005
<0.005
"Q.002
o.2n
40.02
336
0.033
<0.01
0.007
<0.02
<0.06
V54.4
0.147
-fc.oooi :
•fl.Ol
<0.05
0.004
<0.025
134
<0.001
<0.099
<0.01
<0.099
0.013
0.031 .
0.005
<0.02
f/C-S







































'Slurry 1
Pond
Etnuent
3700
11.8"
420
4.8
37.1
16.2
7.0

<0.099
0.001
0.030
0.025
<0.002
0.085
<0.02
175
0.036
<0.10
0.030
0.188
0.067
55.9
0.025
<0.0001
0.030
<0.05
0.019
<0.025
44.5
0.002
<0.099
<0.010
<0.099
<0.010
0.039
<0.005
<0.02
J.I X XU
73r















.























Slinry
Pond
Effluent
1200 >
5.4
100
1.8
<2.0
<1.0
9.0

<0.099
0.002
0.014
0.035
<0.002
0.261
<0.02
64.1
<0.024
<0.01
<0.004
0.271
' <0.06
29.1
0,064
0.0006 -
0.041
<0.05
<0.001
<0.025
226
^ 0.001
<0.099
0.011
<0.099
<0.01
0.029
<0.005
<0.02
*-T


























,










|

Prep.Plant
Recycle
Pond •*
2750
2.2
460
<1.0
4.0
<1.0
2.9

10.0 i
0.005
0.008
<0.005
• 0.007
0.072
0.032
0.254
0.115
0.356
0.056 !
7.63
0.167
0.140
39.6 '
0.0007 :
0.028 !
0.921
0.005
<0.025
43.3
0.001
<0.099 '
<0.01
<0.099
0.140
1.37
<0.005
<0.02
+ 1

Recycle Pone
850
4.0"
38
1.6
4.0
2.0
8.1
-
, <0.099
0.002 !
0.008
0.025
<0.002
0.055
<0.02
55.3
<0.024
<0.01
<0.004
0.181
<0.06
15.8
, <0.01
0.0004
0:029
<0.05
<0.001
<0.025
163
<0.001
<0.099
0.016
<0.099
<0.01
0.093
<0.005
<0.02








































Prep.Plant
Recycle
Pond
680
50
100
5.6
23.3
<1.0
7.2

<0.99
<0.001
0.002
0.11
<0.02
0.09
<0.2
35.0
2.0
<0.1
<0.04
9.0
<0.6
16.0
0.37
0.0009
<0.1
0.53
<0.-001
<0.25
67.0
•cO.OOl
<0.99 .
<0.1
<0.99 .

-------
          OASSICM. PARMdHB  faq/1)

          Total Solids _    '

          •total asperated Solids

          •total Volatile Solids
                   Suspended Solids
          ODD
          TOC
                 (mg/l)
          Aluminum
          Antimony
          Arsenic
          Barium
          Beryllium
          Boron
OO
U1
I-"
          f^ilrrliwn

          Cbbalt
          Copper
          Iron
          Lead
          Magnesium
          tenganese
          Mercury
          tfalybdenum
          Nickel
          Selenium
          Silver
          Sodtin
          Thallium
          Tin
          Titanium'
           Vanadium
           Yttrium
           Zinc
           Cyanide
          Phenols
          Asbestos (fibers/1)
Refuse
Pile Raw
Hater
410
11.4
34
2.2
15.5
3.6
4.0

1.47
0.002
0.003
0.127
<0.002
0.024
<0.02
1
Rafuse'
Pile
Treated
Effluent
260 '
62
36
19.6
29.1
5.5
9.7

<0.99
0.002
0.004
0.17
<0.02
0.11
<0.2
26.5 8.0
<0.024
0.038
0.006
0.509
<0.06
15.5
2.09
0.0048
<0.01
<0.05
0.003
<0.025
38.8
<0.001
<0.099
0.014
<0.099
<0.01
0.168
<0.005
<0.02 j
<0.24
<0.1
<0.04
1.0
<0.6
3.0
<0.2
0.0043
<0.1
<0.5
0.004
<0.250
65.0'.
<0.001
!<0.99
<0.1

-------
    APPENDIX C
ANALYTICAL RESULTS
     OBGANICS
        852

-------
oo
01
u>
Priority Pollutants, pq/1
benzene
chlorcbenzene
1 , 2-dichloroethane
1,1, 1-trichloroethane
1,1,2,2-tetxachloroethene
chlcrofom (trichloranethane)
1 , 2-trans-dichloroethylene
2 ,6-dinitrotoluene
ethylbenzene
netnylene chloride
tridilcxofluoronethane
toluene
bis(2-ethylhexyl) phthalate
di-n-butyl phthalate
dietnyl phthalate
anthracene
ohenanthrene

DRAG TANK
RAH HVRR
1
ND
ND
ND
ND
ID
10
ND
30
ND
- 930
ND
ND
ND
ND
ND
20*
20*
/V
SLURRY
POND
EFFLUENT
ND
ND
ND
ND
ND
ND
ND
ND
ND
1800
ND
ND
ND
ND
ND
ND
ND
Prep
Plant
Slurry
ND
ND
ND
ND
ND
29
ND
ND
ND
199
ND
ND
ND
ND
ND
ND
ND
Settling
Pond
Effluent
ND
ND
ND
ND
>11
>10
ND
ND
>0.2
1,700
ID
>4.2
330
ND
ND
ND
ND
Prep
Plant
Slurry*

















Slurry
Pond
Effluent*

















Clear Lake
Prep
Plant
Recycle*

















--M, V/ MC.~3
                         •Method does not distinguish between these oaqpounds

-------
oo
Ul
*eW7ZH/ ftLftfFS
Priority Pollutants, pg/1
benzene
Peep
Plant
Recycle
Pond
0.3
chlordbenzene MD
1,2-dichloroethane
l,lfl-trichlocoethane
ND
ND
1,1,2,2-tetrachlOToethene l-*
chloroform (tricfaXorcrethaiie)
1,2-trans-dichloroetiiylene
2 6— dinitrotoluene
5.0
ND
ND
ethylbenzene 	 	 	
nethylene chloride
hr 1 r+ilorof luarcnetha*>e **
toluene
bia(2-ethylhexYl) phthalate 200
di-n-butyl phthalate ND
diethyl rfithalate ND

.henanthrene
j ND
ND
Slurry
Pond
Effluent
0.7
ND
to
2.0
13.6
18
1.9
HD
HU
20,000
14
0.3
860
ND
ND
ND
HD
Slurry
Paid
Effluent
12
ND
ND
1.6
5.2
18
1.4
ND
ND
>2.300
ND
5.1
420
ND
790
ND
ND
Acid
Prep
Plant
Recycle
Pond
6.2
ND
ND
ND
4.5
7.3
HD
ND
ND
>4,20cl
ND
l.B
280
Prep
Plant
Recycle
Pond
ND
ND
ND
1.4
ND
12.
1.5
ND
ND
14.000
ND
ND
380
630 i 560
ND
ND
ND
* 	 : .r" —
110
H>
ND
Prep
Plant
Recycle
Pond
ND
ND
HD
ND
ND
152
ND
HD
ND
1,500
ND
ND
ND
ND
ND
ND
ND
Prep
Plant
Hater
Circuit

M>
MD
ND
ND
1.6
ND
MD
ND
7,100
ND
ND
1,200
ND
ND
ND
ND
Slurry
Pond
Effluent
1.2
ND
ND
1.8
20
21
'2.6
ND
ND
20,000
ND
0.3
510
270
ND
ND
ND
A/* I*
SUJRRY
IA3XN
to
ND
NO
ND
ND
78
10

ND
1220
ND
ND





SUJRRY
UOXN
ID
ND
ND
	
ND
ND
20
ND
ND
ND
450
HO
(0
13
ND
ND
ND
to
*/# IO

-------
oo
Oi
Ul
Priority Pollutants, pq/1
benzene
chlorobenzene
1 , 2-diehloroethane
1 ,1 ,1-trichloroethane
1,1,2 ,2-tetrachloroethene
chloroform (trichlorcnethane)
1, 2-trans-dLchloroethylene
2 , 6-dinitrotoluene
ethylJbenzene
•etnylene chloride
trichlorofluocaiethane
toluene
bia(2-ethvlhexYl) phthalate
di-n-butyl phthalate
diethyl phthalate
anthracene
phoianthrene
Refuse
Pile
Raw
Water
4B
ND
ND
ND
ND
45
ND
ND
ND
480
ND
14
ND
ND
ND
ND
ND
Refuse
Treated
Effluent
6.3
ND
ND
1.7
1.2
19
1.7
ND
ND
66,000
22
2.0
6,100
210
ND
ND
ND
Refuse
Pile
Raw
Hater
44
12
ND
ND
ND
ND
Refuse Pile
Runoff Non-
Discharging
Pond
ND
ND
ND
ND
ND
26
i
ND ND
ND
ND 1
1,440
ND
27
ND
ND
ND
ND
ND
ND
ND
654
ND
ND
ND
Refuse
Pile
Non-Dis-
charging
Pond
10
ND
HD
ND
ND
ND
10
ND
ND
967
ND
30
ND
ND *°
ND
ND
ND
ND
ND
ND
REFUSE
PILE
RMfNKtER
ND
ND
ND
ND
i
ND
ND
ND
ND
ND
348
ND
10
ND
ND
ND
ND
ND
                                                                                                                             Storage
                                                                                                                             Pile
                                                                                                                             Runoff
                                                                                                                             Untreated
                                                                                                                                 ND
                                                                                                                                 ND
                                                                                                                                 ND
                                                                                                                                ND
                                                                                                                                ND
476
                                                                                                                                 ND
                                                                                                                                 ND
                                                                                                                                 1,100
                                                                                                                                 ND
                                                                                                                                 ND
                                                                                                                                 10
                                                                                                                                 ND
                                                                                                                                 ND
                                                                                                                                 ND
                                                                                                                                 ND
                                                  MC-/S

-------
                  CONTROL OF TRACE ELEMENT LEACHING FROM
                           COAL PREPARATION WASTES

                  E. M. Wewerka, J. M. Williams, P. Wagner,
                       L. E. Wangen, and J. P. Bertino
                      Los Alamos Scientific Laboratory
                           Los Alamos, New Mexico
                                  ABSTRACT


     The aqueous drainage from coal refuse dumps often is contaminated with
acids and a variety of potentially toxic trace and inorganic constituents.
The Los Alamos Scientific Laboratory is involved in a research program, which
is jointly supported by EPA and DOE, to identify suitable methods to control
or abate this form of environmental pollution.  Control methods that are
currently under investigation include techniques to immobilize or remove the
contaminating substances from coal cleaning wastes prior to disposal, treat-
ment of refuse dumps to prevent the release of pollutants from them, and
treatment of contaminated waters as they emerge from refuse disposal sites.
The emphasis of this paper is to review experimental results that have been
obtained in this program to date, and to discuss the various environmental
control options available to the coal cleaning industry.
                                      856

-------
                                 INTRODUCTION



     The mineral wastes from coal preparation and mine development constitute



a major environmental problem.  Over 3-billion tons of these materials have



accumulated in the U.S., and the current annual rate of waste production of



100-million tons per year is expected to double within a decade (National



Academy of Sciences, 1975).  The total number of coal waste dumps is estimated



to be between 3000 and 5000 of which one-half pose some type of health, en-




vironmental or safety problem (National Academy of Sciences, 1975).  Struc-



tural weaknesses in coal refuse banks have led to tragic landslides such as



those at Buffalo Creek, WV and Aberfan, Wales, and the 300 or so burning




waste banks are a major source of air pollution.   In addition to these prob-




lems, there is growing concern about environmental effects from the trace




elements that are present in the  highly mineralized,  acid drainage from coal



refuse dumps that affects many thousands of miles of streams and waterways.
                                   857

-------
      Although it has been established  that  the drainage  from  coal  refuse  dumps



  is  often highly contaminated with trace or  inorganic elements, little  is  known



  about  the quantities of undesirable elements that are released into  the envi-



  ronment from this source (Wewerka, et  al.,  1976).  Development of  the  neces-



  sary control technologies for human and environmental protection requires



  quantitative evaluation of the extent  and severity of the problem.  LASL has



  been directed by DOE and EPA to assess the nature and magnitude of the trace



  elements in the drainage from coal preparation wastes, to identify the trace



  elements of greatest environmental concern in these materials, and to evaluate



  required pollution control technology  for this form of environmental contami-



  nation.



      This program is divided into several research activities.  The initial



  efforts included studies of the structure and weathering and leaching behav-



  iors of the trace elements in selected samples of high sulfur refuse and



  coal (Wewerka,  et al.,  1978a and b).   These investigations established the



  overall potential of these  materials  to cause trar.e element contamination,



  and revealed the identities  of  the  specific trace elements of concern in the
                                                                            «*


 refuse and  coal  pile effluents.   The  information  gathered on refuse and coal



 structure and environmental  behavior provided the basis  for the present stage



 of the program,  which involves assessment  or development  of control technology



 to lessen the environmental  impact of  trace  element pollution  of  coal or refuse



 associated waters.



     Investigations are now underway to identify  the options for  preventing



•or controlling trace element contamination of the. drainages  from  high sulfur
                                      858

-------
coal preparation wastes.   Two basic approaches to effect trace element control




are being considered in this work.   The first involves methods to treat newly



produced coal refuse either at the  preparation plant or during disposal to pre-




vent the eventual release of trace  elements from the disposal site.   These




techniques include refuse calcining, treatment of the refuse to remove acid



forming constituents and labile trace elements, and the application of adsorb-



ents or attenuating agents to refuse disposal sites.  The second approach con-




cerns techniques to reduce or abate the trace-element composition of already



contaminated waters emerging from refuse dumps or disposal areas.  Under con-




sideration here are such methods as alkaline neutralization, ion exchange,



reverse osmosis, chelation and application of selected adsorbents.  Some of



the experimental results from these researches are reviewed and discussed in




the following sections of this paper.




                                 EXPERIMENTAL



     The coal preparation wastes used in this work were collected from three




coal cleaning plants (designated Plants A, B and C) in the Illinois Basin.




These samples of high sulfur coal refuse are typical of the wastes produced




by cleaning of the major coal types currently mined in the region (Wewerka,



et al., 1978a).




     The mineral and elemental compositions of the raw refuse samples, cal-




cined refuse materials and mixtures of refuse with other materials were an-




alyzed by x-ray diffraction, neutron activation analysis, atomic absorption



spectrophotometry, optical emission spectroscopy and wet chemical methods.



     Both static and dynamic leaching experiments were conducted to evaluate




the behavior of the trace elements  in the Illinois Basin coal wastes under




simulated environmental conditions  and to test the effectiveness of potential



environmental control methods.  The static experiments were carried out by






                                     859

-------
 agitating a known quantity of crushed rafuse or composite  (50 g)  in the pres-


 ence of a constant volume of distilled water (250 ml)  for  varying periods of


 time.  In the dynamic  or column leaching tests, a crushed  sample  (~ 1500 g) was


 packed into a 70-cm-long by 4.6 cm-diam glass column and distilled water waa


 continuously monitored through the  column at a rate  of 0.5 ml/min.   The ele-.


 mental compositions of the experimental leachates were determined by the tech-


 niques mentioned  above.


      The details  of the  experimental  set ups and analytical procedures  used


 in this study appear in  two recently  published reports (Wewerka,  et al.,


 1978a and b).


                             RESULTS AND DISCUSSION


      The Illinois Basin  coal refuse samples  used in  this study were composed


 of clay minerals  (illite,  kaolinite and other more complex clays),  quartz,


 pyrlte,  and marcasite.   Interspersed  throughout the mineral network were  a


 variety of minor  minerals  and  residual  coal.   The  relative magnitudes of  the


 major minerals constituting these refuse materials did not vary greatly  from


 sample to  sample.


      Elementally,  these  refuse materials were  found to be very complex.   Some


 55 elements were  identified  in most of  the refuse  samples and undoubtedly


 there are  more (Wewerka, et al., 1978b).  The most abundant of these elements,


 Fe, Al and  Si, comprise  the structures of the major mineral systems.  The
                                                                          .*

minor elements are present as constituents of minor minerals, components of


 the residual coal or substituents in the major mineral lattices.


      Static and dynamic leaching experiments were performed to evaluate the


trace element behavior  of Illinois Basin coal wastes under simulated weather-


Ing conditions.  These  experiments were done to provide information needed


to predict quantitatively the trace element levels in the drainage  from coal



                                    860

-------
refuse dumps or disposal areas and to identify those elements of environ-




mental concern.



     Perhaps the single most important characteristic of the high sulfur ref-




use materials during aqueous leaching is their pronounced tendency to rapidly




produce acidic leachates.  This is due to the oxidative degradation of the



pyrite and marcasite present in the refuse.  Acid formation is partially atten-



uated by calcite or other neutralizing species in the refuse, but the leachates




from the Illinois Basin refuse samples that we studied nearly always had pH




values in the range of 2 to 4.  These acid leachates are very efficient in



dissolving or degrading many of the mineral components of the refuse, and



thus releasing the trace or minor elements associated with them.  Figure 1 de-



picts the relationship between leachate pH and the dissolved solids contents




of the leachates in contact with the various refuse samples.



     Two types of trace elementleachabilities were observed for all of the




Illinois Basin retuse samples.  Because ot their abundances in  the reruse




some elements  (such as Fe, Al, Ca, Mg) are released in relatively high absolute




quantities  (Table 1).  Other, less abundant elements  (for example, Ni, Co, Zn,




Cu) are leached in a high proportion  to the total of  each present, although




this may not be a large amount in the absolute sense  (Table  2).  The  first



group is highly concentrated  in the leachates, the  second is highly  leachable




from the refuse.  A similar trace element  release behavior wae  also  observed




during the  dynamic leaching of these  refuse materials.



     Multimedia Environmental Goals  (MEGs) were  used  to  identify  the hazardous




trace elements in the  leachates from the refuse  materials  studied  (Cleland




and Kingsbury, 1977).MEGs are defined as levels  of  potentially hazardous ef-




fluents that are appropriate  for  preventing negative  effects in exposed eco-



systems or  represent control  limits  achievable through current technology.





                                     861

-------
       O
       V)

       Q
       LJ


       1
       .<

• PLANT A

• PLANT B

A PLANT C
Figure 1.  The rclaricnshlp between pTT and  total  dissolved solids  for  lc-ac'i-

aues Iioiu static ieaciiing experimencs wich  Illinois aaain coal refuse.
                                    862

-------
            Leachate concentration                  Leachate concentration
Element     	yg/mil	      Element       u	yg/m&	
  Fe                16400                Co                 18
  Ca                  680                As                  7
  Al                  570                Cu                  3.7
  Mg                  216                Ti                < 2
  K                    90                V                < 2
  Na                   74                Cr                  1.1
  Zn                   48                Be                  0.2
  Mn                   40                Cd                  0.2
  Ni                   31                Pb                < 0.2
Table 1.  Trace elements released from Illinois  Basin coal refuse  during
static leaching.  Results from experiment with Plant  B refuse.
Conditions:  50 g of -20 mesh refuse agitated with 250 m£ water, 1 day,
room temperature, open vessel.
                 Percent of                                 Percent of
Element         total leached             Element          total leached
  Ca                  79                    Cu                  7
  Co                  60                    Be                  6
  Ni                  46                    Na                  5
  Zn                  42                    V                 < 2.5
  Cd                  35                    Cr                  1.2
  Mn                  28                    Al                  1.2
  Fe                  14                    Pb                < 1.2
  As                    9                    K                   0.8
  Mg                    9                    Ti                < 0.1
Table  2.  Percent of  trace elements released  from Illinois Basin Plant B
coal refuse  during  static leaching.  Conditions:  50 g of -20 mesh refuse
agitated with  250 m£  water,  1  day, room  temperature, open vessel.
                                863

-------
 The utility of the MEG system Is that it provides a means for directly deter-

 mining which of the contaminants in waste water solutions, such as those of

 interest here, exceed concentrations that are safely assimilated by the en-

 vironment.  Application of the MEG routine to data on the composition of ref-

 use leachates obtained in this work, and from available information in the

 literature, has revealed that nine elements, Fe, Al, Ma, Co, Ni, Zn, As and

 Cd are frequently present in potentially hazardous amounts.  Although these

 elements are not necessarily the only ones in the refuse leachates that could

 conceivably be troublesome under all circumstances,  they are, however,  the

 priority elements that are receiving the greatest emphasis in the current

 work on environmental  control technology.

     Research has now  been started  to identify suitable  means to control

 trace  element contamination of the  drainages from high sulfur coal prepara-

 tion wastes.   These control techniques can roughly be  divided into three

 categories:   (1)   immobilization or removal of contaminants prior to disposal

 of  the refuse materials;  (2)  waste dump treatment to  prevent the release of

 undesirable substance  from it; and  (3)  treatment  of already  contaminated

 water  discharged from  existing refuse  disposal sites.    Encouraging results

 have been obtained from current research on each of these three  types of en-

 vironmental control techniques.

     One of the more promising techniques under consideration to immobilize

 the hazardous elements in high sulfur coal refuse materials is calcining of

 the refuse to high temperatures to produce an inert glass-like slag.   Present

work in this area is  directed both at identifying the chemical and physical
* These studies are directed at environmental control of both surface and
  groundwater contamination  that may result from the disposal of coal prepa-
  ration wastes either on or near the surface or the deep burial of them in
  strip or underground mines.
                                    864

-------
changes brought about in the refuse structure as a result  of the heat  treat-


ment, and at defining the consequent decreases in trace element mobilities.


     Several calcining experiments have been performed to  determine the opti-


mum heat treatment conditions necessary to chemically immobilize the poten-


tially toxic trace elements in the refuse matrix.  These experiments were


performed using high sulfur coal preparation wastes from Plants B and  C


(Illinois Basin).  The wastes were ground to -20 mesh and  calcined in  air at


600, 800, 1000, and 1200°C for a 2 h period.  The success  of the calcining


treatment at reducing the trace element mobilities of the  refuse samples is


illustrated by the data from a comparison leaching experiment incorporating


the refuse sample that had been calcined at 1000°C (Table  3).  The calcined


and uncalcined refuse samples listed in the table had been subjected to static


leaching for 48 h.  It is seen from the information in the table that  calcin-


ing has essentially eliminated the acid generating potential of the refuse


samples ar* thst the TDS ccr.tectc of the resulting lcschat£3 was substantially


reduced.  More important is the fact that the concentrations of the abrevi-


ated group of toxic elements listed have been reduced in the calcined  refuse


leachates by about two orders of magnitude over the concentrations in  the


leachates produced from the raw refuse materials.


     Physically, the samples calcined at 1000 and 1200°C began to sinter.


X-ray diffraction analyses of the calcined materials suggests that at these

                                                                           *
temperatures considerable breakdown of the clay mineral structures has begun


to occur.  This apparently results in significant encapsulation of the


leachable refuse components.  The acid forming constituents of the refuse


samples  (pyrite and marcasite) are transformed at lower temperatures to vol-


atile sulfur compounds.  This is evidenced by the reduction of the sulfur


content  of  the Plant B refuse material from 13.4 wt %  to 0.7 wt % after



                                      865

-------
                           Uncalcined                         Calcined
                             Refuse                            Refuse
     PH                        2.3                              C.C
     TDS(%)                    0.6                              0.2
     Al                       40                                0.3
     Fe                      240                              < 0.02
     Mn                        2.3                              0.02
     Co                        1.1                              0.01
     Ni                        1.9                              0.01
     Zn                        1.1                              0.05
Table 3.   Trace element leachability of a coal refuse sample calcined at
1000°C for 2 h.  Elemental compositions of leachates  are reported as ppm,
                               866

-------
calcining to 800°C.  This undoubtedly accounts for the marked reduction of




the acid generating potential of the calcined refuse samples.




      In addition to the research just described on refuse clacining, studies



are also being conducted on the effectiveness of preleaching the refuse ma-



terials to remove both the acid forming constituents and the mobile trace



elements prior to disposal.  This work involves the application of water in




conjunction with a variety of oxidizing agents to effect contaminant removal.



      Several methods are being considered to treat coal refuse during dispos-



al to prevent the release of trace contaminants during subsequent waste dump



weathering or leaching by surface or ground water.  These include codisposal




of the refuse material with neutralizing agents or trace element adsorbents



and the application of water tight sealants to all or parts of the waste



dump mass.




     Especially promising among these techniques is the codisposal of the




acid refuse materials with alkaline agents such as lime.  In one set of ex-



periments, for example, powdered lime in varying amounts (3 to 50 g) was




slurried in 150 ml of distilled water with -3/8 in. high sulfur coal refuse




(530 g, from Illinois Basin Plant B).  The resultant mixture was subsequent-



ly filtered,  dried in air at 50°C, and repulverized to -3/8 in. particles.



Four different lime concentrations were employed; 0.5, 1.5, 3 and 10 wt %.



In addition,  a control refuse sample that had not been lime treated was al-



so incorporated into this study for comparison purposes.




     Column leaching experiments were conducted with about 500 g of each of



the above samples to determine the effects of the lime additions.  The ref-




use mixtures  were packed into pyrex columns 25 cm long by 5 cm diameter and



subsequently  leached with distilled water at a flow rate of p.5 ml/min




until more than 4 £ of water had been passed through the refuse beds.  The






                                     867

-------
 composition of the leachates after  about-300 ml  of  water  had passed  through


 the columns containing the  refuse mixed with 3 and  10 wt  %  lime and  also


 through a control  column containing untreated refuse are  given in Table 4.


      Although the  data are  not  listed  in  Table 4, the leaching experiments


 showed that the  addition of 0,5 and 1.5 wt  % line to the  acid refuse had


 only a small influence on leachate  pH  and trace  element concentration because


 the acid neutralization provided by these amounts of lime was overwhelmed


 by  the acid generating capability of the  refuse.  The additions of 3 and 10


 wt  % of lime,  on the other  hand (Table 4),  did indeed effectively counteract


 the acid properties of the  refuse;  the pH of the leachates  for these two


 systems are elevated to acceptable  levels and the trace element compositions


 of  the leachates from  the treated refuse  samples are significantly reduced


 in  all instances,


      The system  containing  3 wt  % lime is especially interesting because a


 leachate pH of 7 was maintained  for nearly  the entire duration of the leach-


 ing experiment  (until  4.2 £ had  been passed  through the column).  TDS values


 for this refuse-lime combination were  also very respectable (ranging down-


 ward from about  0.6 wt  %) especially considering that the dissolution of


 the lime itself  adds substantially  to  the dissolved solids content of the


 solution.


      As a result of experiments  like these,   the addition of alkaline agents
                                                                          *

 to  refuse disposal sites is viewed  to  be a very promising means to control


 acid  generation and trace element releases from high sulfur coal refuse, and


 the research effort in this area is being continued.


     Another potentially fruitful way  to retain the leachable contaminants


within a refuse disposal site is to intermix the acid coal wastes with suit-


able amounts of trace element attenuating agents.  An example of one of the



                                     868

-------
            Untreated refuse
                Control
PH
TDS(%)
Al
Fe
Mn
Co
Ni
Zn
2
4
720
7800
22
12
18
29
Refuse + 3% Lime
       7
       0.4
     < 0.6
      40
       1
       0.3
       0.5
       0.1
Refuse + 10% Liyie
      12
       0.5
     < 0.5
     < 0.1
     < 0.02
       0.1
       0.1
       0.02
Table 4.  A few results from a column leaching study of Illinois Basin coal
refuse that had been lime treated.  Elemental compositions of leachates are
given as ppm.   Leachate volume 300 m£.
                                     869

-------
  preliminary studies  conducted in this area will  illustrate the potential



  utility of  the method.




       In this experiment, acidic  coal  refuse leachates were equilibrated  with




  several solid sorbent materials  to  evaluate their trace element attenuation




  capabilities, prior  to using  these  agents  in codisposal experiments.  The




  solids  used were illite, montmorillonite,  and kaolinite clays;  a sample  of




  scrubber sludge, precipitator ash and  two  samples of bottom ash, each from




  different power plants; an acid drainage treatment sludge; and  a clay rich




  soil.  The experimental procedure consisted of shaking the solid (50 g) with




  the coal refuse leachate (150 ml) for 15 h, measuring the resulting pH and




 analyzing the filtrate for trace elements.




      Several of these agents proved to be quite effective in attenuating the




 acid and trace  element contents of the refuse  leachates.   Among these were




 the fly ash, scrubber sludge and AMD sludge and  the  illite and montmorillonite




 clays (Table 5).   (An important point to distinguish here  is that  the fly ash




 and sludges  are  themselves  alkaline  agents, so the effectiveness of these two




 materials may at least in part be due  to pH control  of the solutions rather




 than direct  trace element adsorption.)   The bottom ash samples,  not unexpect-




 edly proved  to be too chemically   intractable to  interact  with the  contamin-




 ated leachates and the one  soil studied did not exhibit sufficient  exchange




 capacity to be of use.  Other experiments are being conducted, however, to




 test the  trace element and acid absorbtivities of a wide variety a  calcareous




 and  noncalcareous soils, and weathered and  nonweathered soils  from  the Illinois



 Basin.





     Studies  are also  underway to evaluate  several techniques for treating




refuse drainage  water  that  is contaminated with acids and toxic  trace elements.
                                    870

-------
          Untreated leachate
               Control	       Scrubber Sludge       Fly Ash       Illite
PH                2.6                   7.3
Al               10                   < 0.2
Fe              107                  <  0.1
Mn                4                     2.2
Co                1.9                   0.7
Ni                2.6                   0.8
Zn                1.0                   0.6
Table 5.  The attenuation of contaminated coal refuse leachates by various
agents.  Elemental concentrations in leachates reported as ppm.
9.6
0.6
0.2
0.04
0.1
< 0.05
0.02
9.1
0.6
0.3
0.3
0.1
0.07
0.35
                                       871

-------
 Included among  these are alkaline neutralization, ion exchange, reverse osmo-




 sis, chelation  and biological treatment.




     These techniques have proven fruitful in attenuating contaminants in




 many types of industrial or mining waste waters, and may be effective in treat-




 ing coal refuse drainage.




     One of the most promising of these control techniques, alkaline neutral-




 ization, is currently used extensively to treat acid drainage from coal mines.




 While it is well known that alkaline neutralization is very effective in con-




 trolling the acid and overall salt compositions of mine waste waters, the de-




 gree of control that this method exerts over some of the more highly leach-




 able toxic trace elements remains to be established (Wewerka, et al., 1976).




 Elaboration of  this latter point is the basis for one of the studies now being




 conducted in this area.



     In this work, the degree to which the solubilities of the various trace




 elements in the drainage from high sulfur coal refuse are effected by neutral-




 ization with such agents as limestone and lime is being investigated.  The




 experiments are basically titrations in which limestone, lime or lye (the




 standard base) were added to one liter of contamined refuse drainage until




 a predetermined value of the pH was reached.  The solutions (or slurries)




 were allowed to sit overnight, filtered, and the pH, dissolved solids and




 trace element contents of them were measured.  The results of these experi-




 ments are summarized in Table 6.




     Examination of Table 6 shows that neutralization is an effective tech-




 nique for decreasing trace element concentrations in refuse waste water.




 The pH and Fe contents of the treated solutions are within acceptable limits,




 based on the 1977 EPA effluent limitation guidelines for coal preparation




plants (Fe ^3.5 ug/ml averaged for 30 days, pH 6-9).   Mn, however, exceeds






                                    872

-------
              Untreated Leachate
              _ Control
PH                   1.1
TDS(%)               0.5
Al                  18
Fe                 820
Mn                   3.6
Co                   2.0
Ni                   3.2
Zn.                   3.9
Lye
6
3.4
< 0.2
0.06
0.07
0.05
0.05
0.02
Limestone
7.1
3.2
< 0.2
0.3
6.4
1.0
1.0
0.1
Lime
6.6
3.2
< 0.2
0.3
1.0
0.6
0.7
0.1
Table 6.  Alkaline neutralization of contaminated refuse drainage.  Drainage
compositions reported as ppm.
                                       873

-------
the acceptable level of 2.5-3 yg/ml (averaged for 30 days)  in the limestone

case.  Further work in the area of alkaline neutralization of refuse drainage

involves its application to more highly contaminated drainage to investigate

coprecipitation phenomenon, and the scale up of the process to more life-like

circumstances.

                                    SUMMARY

     The purpose of this paper was to present an overview of research under-

way at Los Alamos Scientific Laboratory to identify the various options for

controlling trace element contamination of coal refuse drainages.  The control

methods under consideration include chemical and physical methods to immobilize

or remove undesirable contaminants prior to refuse disposal, the treatment of

refuse disposal sites with attenuating agents or sealants to prevent the dis-

charge  of contaminated water, and the direct treatment of refuse drainage

as it emerges from the refuse disposal site.  The initial results from these

studies suggest that many of the techniques being considered are technically

feasible for controlling trace element contamination of refuse dump drainage.

                                  REFERENCES

Cleland, J. G., and Kingsbury, G. L. 1977.  Multimedia environmental goals
     for environmental assessment.  Vol. I and II.  EPA-600/7-77-136a, b.

National Academy of Sciences.  1975.  Underground disposal of coal mine wastes.
     National Science Foundation, Washington, DC.

Wewerka, E. M., Williams, J. M., Wanek, P. L., and Olsen, J. D.  1976.
     Environmental contamination from trace elements in coal preparation
     wastes:  a literature review and assessment.  EPA-600/7-76-007.

Wewerka, E. M. and Williams, J. M.  1978a.  Trace element  characterization of
     coal wastes — first  annual report.   EPA-600/7-78-028.

Wewerka, E. M., Williams,  J. M., Vanderborgh,  N. E.  , Harmon, A. W., Wagner, P.,
     Wanek, P. L. and Olsen, J. D.  1978b.  Trace element  characterization of
     coal wastes — second annual progress report.   EPA-600/7-78-028a.
                                    874

-------
              STABILIZATION OF COAL PREPARATION PLANT SLUDGES

                              David C. Hoffman
                             Dravo Lime Company
                          Pittsburgh, Pennsylvania
                                  ABSTRACT
     As operating costs continue to increase, coal producers search for new
processes to reduce costs.  One major area for improvement is fine coal
refuse handling and disposal.  Current disposal practices for this material
utilize large permanent settling ponds, temporary settling ponds, large
permanent impoundments, or mechanically dewatered solids for landfill disposal.
This discussion will briefly review Calcilox* additive stabilization tech-
niques, present the latest technical developments, and illustrate Calcilox
additive disposal alternatives that can technically and economically improve
fine coal refuse disposal.
 *  Calcilox  (trademark)  additive  is a  registered  trademark of Dravo Corporation.


                                      875

-------
Introduction



     Today, the major energy reserve in the United States is



coal, which accounts for nearly 80% of the known recoverable



resources.  Reasonably priced energy, in all forms, is needed



to maintain our industrial productivity and high standard of



living.  Coal must provide a significant portion of our



present and future energy requirements.  1976 production of



mined bituminous and lignite coals was nearly 679 million



tons.  Energy planners believe this production level must be



raised to 1.2 billion tons by 1985 to attain our national/



energy goals.  This will require more numerous and more



efficient coal mining, preparation, and transportation



operations.





     There are many difficult operations in coal mining; one



of the most troublesome being the disposal of coal preparation



wastes, in particular, the fines portion.  Research by Dravo



Lime Company has led to the application of an additive, Calcilox,



that when added to waste solids, produces a stable material



with the consistency of compacted soil.  With these greatly



improved characteristics, recognized disposal means can then



be utilized for the fines.





Discussion



     Generally, a coal preparation plant produces two types



of refuse; a coarse fraction (plus 28 mesh), and a fine fraction



(minus 28 mesh).  These two wastes can be handled separately or
                              876

-------
mixed together based on the preparation plant circuitry and/or



disposal criteria.  Figure 1, Alternate Refuse Handling Modes,



illustrates some typical disposal methods.  Based on our



experience, the coarse refuse, alone, does present serious



disposal problems because of the size consist, low moisture,



compactibility, and cohesive strength.  These properties can



be utilized in designing safe and environmentally acceptable



landfill disposal sites.





     However, the fine refuse is quite different and its



disposal may hot be straightforward.  Typically, the fine



refuse solids are in a slurry form ranging from 15% to 45%



solids, by dry weight, or exist as a 55% to 75% thixotropic



solids cake produced by a vacuum disc filter, solid bowl



centrifuge, or a plate and frame filter press.  In either a



cake or slurry form, the solids are not readily dewatered



further; will easily reslurry; and do not possess significant



cohesive strength for permanent landfill disposal.  The



latest statistics indicate that the 1976 mined bituminous



and lignite coal tonnage was 679 million tons with 269 million



tons mechanically cleaned.   It is estimated that the amount of



refuse produced was 89 million tons consisting of 16 million



tons as fines and 73 million tons as coarse refuse.  An



important underlying fact in dealing with the disposal of



these quantities is that over 80% of the coal cleaning plants



are located in the states of West Virginia, Kentucky,
                              877

-------
                               II	.
1
L-n
1
j OlmiWHM B¥ TRUCK Ct
L_
1
1
I—
	 1
| HMIt WO D1ITRIDUH
1 ' H TMCI M CCUPU
| 1 UMIWB
— ' 1 	

	 1
1
1
	 1

r
i
I
i_
l— O*U W7ILT&ITI
~l
1
IICQMUAM TBMMf AND DC
MD/OM KMTU LOMM
in_
n
"•I
i
Figure - 1
          ALTERNATE REFUSE HANDLING MODES
                   878

-------
Pennsylvania, Virginia, Illinois and Ohio.  In the coal



producing regions of these states, the topography ranges from



gently sloping to steeply mountainous; not conducive for



landfill disposal of a fluid mass such as the fine coal refuse.





     A common fines disposal method is to pump the thickener



underflow to a lagoon and allow the solids to settle.  When



topography is favorable for the lagooning approach, several



lagoons may be excavated to provide a long filling lifetime.



After these ponds are full, they may be abandoned and new ones



excavated.  In the major Appalachian coal fields, topography



usually does not favor extensive pond systems.  Generally,



a pond or two are excavated, filled, and the settled solids



reexcavated and disposed of.  The pond or ponds are then



refilled, and the cycle repeated.  The major problem with



handling the settled fines is the fluidity of the material



at normal settled solids concentration between 45% and  60%



 (Figure 2, Fluid Settled Solids).  Due to the clayish nature



of most fine refuse, the solids will easily reslurry even



after the solids have been air dried.





     As an alternate for ponds  or impoundments,  the thickener



underflow may be mechanically dewatered  to  (1) close the plant



water circuit,  (2)  save disposal  space,  and  (3)  attempt to



improve the  handling characteristics  of  the slurry.  Assuming



ideal success in all handling stages,  the dewatered material
                              879

-------
Figure -• 2
          FLUID SETTLED SOLIDS
                 880

-------
could be mixed with the coarse refuse and compacted into a

stable landfill.  Unfortunately, this is a huge, seldom

realized assumption.  In actual practice, the cakes are

extremely difficult to homogeneously mix into the coarse

refuse.  They remain in large, sticky masses which gum up

conveyors, bins, and trucks.  In summary, the dewatered fines,

whether intact or partially mixed with the coarse material,

present a troublesome handling and disposal task.


     We believe that the disposal of these fine refuse solids

can be dramatically improved.  One viable solution is the

addition of a chemical, Calcilox additive, to the refuse

slurry or dewatered cake.  Calcilox additive (Figure 3) is

a dry, free-flowing light grey powder of inorganic origin

and it is chemically activated with water.  Calcilox additive

is mixed into the refuse on a weight percentage of the dry

refuse solids.  The net result of this addition will be the

development of definitive engineering properties in the refuse;

such as compressive strength, cohesion, shear resistance, and

reduced water permeability.


     The most recent technical study    has just been com-

pleted for the Pittsburgh Branch of the Department of Energy
   Management of Coal Preparation Fine Wastes Without Disposal
   Ponds, D. C. Hoffman, R. W. Briaas. S. R. Michalski. Dravo
   Lime Company, June 15, 1978, Contract No. J0177050, Depart-
   ment of Energy, Branch of Procurement, Washington, D.C.
                              881

-------
Figure - 3
         "CALCILOX, A DRY FREE FLOWING POWDER

-------
 (formerly the United States Bureau of Mines) investigating



 the general effects of chemical stabilization on fine coal



 refuse.  Fine refuse samples were collected from various



 preparation plants representative of "typical" operations



 in the Eastern bituminous coal fields.  One of the prime



 objectives of study was to investigate the untreated, as-



 received properties of these fine solids.  Table I, Untreated



 Fine Coal Refuse, tabulates the important physical properties



 of permeability and direct shear results for the samples



 tested as a settled slurry and as a filter cake.  In reviewing



 the data, it must be pointed out that the solids content of



 the slurries and cakes is quite high due to the laboratory



 conditions.  Field investigations indicate that settled solids



 usually run between 45% and 60% solids while mechanically



 dewatered cakes may range from 55% to 75% solids.  The major



 points illustrated here are the overall lack of any cohesive



 strength (less than 1 psi) and low permeabilities (10~6) on



 both the settled solids and filter cakes.  These two factors



 contribute quite heavily to the fluidity of large masses of



 fine coal refuse.






     The chemical additives tested in this study were hydrated



 lime, Portland Type 1 cement, and Calcilox additive.  Lime and



Portland cement have been known to impart some stabilizing



effects to fine refuse but no quantitative results have been



 reported.  Secondly, all three additives are commercially
                              883

-------
                                                                          TABLE  I


                                                              UNTREATED PINE COAL REFUSE


Sample
Mo.


11 04
1105
1106
1107
1110
1111
1112
1113
Hill
PermeabU ity
Settled Slurry


cm/sec .

f..0x!0~b
l.Oxlo"5
7.4xlO~b
2.6x10 6
-£
4.4x10 b
,f

-------
available and are competitively priced.  Based on Dravo's



experience, the most economic use of chemical stabilization



techniques occurs with additive dosages ranging from 5% to



15%, on a dry solid basis, high solids cakes to thickener



underflows, respectively.  With this in mind, stabilization



tests were conducted covering the range of typical thickener



underflows (25% to 35% solids) and high solids filter cakes



(70% to 82% solids).





     The procedure used to evaluate the effectiveness of each



additive was the development of unconfined compressive strength



after 40 days of curing.  Table II, 40-day Unconfined Com-



pression Strength, lists the results obtained for ambient



temperature stabilization.  Using the criterion of highest



possible strength, this figure illustrates that Calcilox



additive is the best for treating thickener underflows in



the 25% to 35% solids range.  In seven out of the nine filter



cake samples, Calcilox is also superior to Portland cement and in



all cases, vastly superior to lime additions.  In actual



applications, the dosage level and strength desired will vary



and is dependent on each specific disposal mode and can be



verified by laboratory testing.





Recommended Stabilization Methods



     Thus far, we have attempted to define fine coal refuse



disposal and to present the latest laboratory results.  The
                              885

-------
                                                             TABLE  II
                                              40-DAY UNCONFINED COMPRESSION STRENGTH
                                                                (PSD
Treatment
Additive
Untreated
5t Portland
Type I
5% Lime
5% Calcilox A
5% Calcilox B
10% Portland
Type I
10% Lime
10% Calcilox A
10% Calcilox B
15% Portland
Type I
151 Lime
15% Calcilox A
15% Calcilox B
Mixed
Solids
%
25
35(3)
FCVJ/
35
FC
35
FC
35
FC
35
25
35
FC
25
35
FC
25
35
FC
35
25
35
25
35
25
35
35
Sample Number
1104
72o(l)
JJ)
*
*
*
95.9
*
37.2
*
78.6
*
*
1.6
141.3
*
*
39. B
6.1
15.1
368.6
10.3
*
4.5
*
*
15.4
24.4
35.9
1105
72°
*
*
6.6
*
85.0
*
23.1
8.8
124.9
7.2
*
0.8
165.3
*
*
12.6
39.4
27.0
188.5
37.5
*
2.2
*
*
31.0
30.2
86.1
1106
72°
*
*
*
*
73.9
*
20.0
8.5
80.3
4.9
*
2.8
141.0
*
*
22.2
19.7
33.9
494.4
36.1
1.9
3.6
*
*
80.6
59.4
80.3
1107
72°
*
*
*
*
123.2
*
23.2
10.0
218.2
7.5
*
*
76.1
*
*
15.2
20.6
38.9
233.7
32.8
*
*
*
*
47.7
35.7
87.9
1110
72°
*
*
*
*
18.7
*
7.6
0.8
81.3
1.4
*
*
115.5
*
16.4
5.4
10.8
120.0
19.5
*
1.9
*
*
12.1
17.1
34.4
1111
72°
*
*
*
*
67.6
*
*
1.6
50.7
2.6
*
141.5
*
*
13.6
9.0
14.1
116.6
12.2
*
*
*
15.5
21.0
26.4
1112
72°
*
*
5.1
50.5
8.5
4.8
98.5
10.2
*
159.4
*
13.3
7.7
4.5
69.9
33.7
*
*
*
*
6.6
13.3
39.3
1113
72°
*
*
*
*
60.4
*
9.6
1.4
106.9
1.5
0.9
160.9
*
*
14.6
3.7
8.4
231.2
16.4
*
1.9
*
*
10.3
24.2
39.5
1114
72°
*
*
*
*
67.1
*
15.6
2.0
89.1
2.0
*
145.4
*
*
16.1
4.7
4.4
224.5
6.8
*
*
*
11.6
15.0
24.0
00
00

             curing temperature measured in degrees Fahrenheit.
             *  Indicates specimen did not have a measurable strength at 40 days.
             FC -  Filter cake solids level - 70%-82% Solids

-------
following represents disposal modes that can be utilized for



full-scale operations.





     1.  Interim Stabilization    (Figure 4)



         Fine refuse thickener underflow is treated with



Calcilox additive and deposited into temporary curing ponds.



The duration of the curing period will vary from days to



several weeks depending upon the nature of the refuse, the



Calcilox additive dosage, the slurry solids etc.  When the



handling characteristics of the slurry are sufficiently



improved, it is excavated by dragline or other methods and



is transported to a permanent landfill disposal site.  By



using the correct amount of Calcilox additive and excavating



the material before the reaction has produced a very rigid



mass, it is possible to continue the hardening after the



material is placed in its final disposal location.  This



alternate requires some space and due to multiple handling,



does represent a relatively higher operating cost than the



following methods 2, 3, or 4.  Operating costs are compen-



sated for by increased operational flexibility and control.



In addition, supernatant can be easily reclaimed for reuse in



the preparation plant.





     2.  High Solids Cake - Separate Disposal   (Figure 5)



         For those companies which already own mechanical



dewatering equipment, it is possible to treat the resulting
                              887

-------
           Figure -  4
                     INTERIM STABILIZATION
Figure - 5
          HIGH SOLIDS CAKE - SEPARATE DISPOSAL
                    888

-------
cakes at a somewhat lower additive cost than would be the

cost for stabilizing thickener underflow.  It is possible to

excavate small pockets or lagoons within the coarse refuse

deposit.  Treated cake is retained in these pockets until the

Calcilox additive has hardened the material sufficiently to

support earthmoving equipment.  The pocket can then be graded,

compacted, and covered with coarse refuse.  Stabilization

rates for cakes are rapid so that these pockets can be covered

quickly if required for the management of the landfill.  Again,

this method offers some flexibility, and lower operating costs

when compared to interim ponding.  This "pocket" method does

not appear to be suitable for thickener underflows unless the

coal company can construct large enough pockets to meet the

longer stabilization periods.  In addition, the costs of a

mobile and flexible piping system may be prohibitive.


     3.  High Solids Cake-Coarse and Fine Refuse Disposal
         (Figure 6)

         The third disposal mode, mixing coarse and Calcilox

additive treated fines, may be the most easily adapted to an

existing plant that currently combines a dewatered fine refuse

with the coarse reject.  In most plants the amount of coarse

refuse (by weight and volume) is several times the amount of

fine refuse.  However, the combination of the two generally

creates a nearly unmanageable situation in terms of immediate

handling and long-term stability.  After laboratory testing

of the fine refuse cake with Calcilox additive, an optimum
                              889

-------
Figure - 6
  HIGH SOLIDS CAKE - COARSE AND FINE REFUSE DISPOSAL
                        890

-------
dosage is determined.  Subsequent laboratory testing of



mixtures of coarse refuse and treated fine refuse cake can



determine the proper ratio of coarse to fine refuse for



immediate handling properties.  The addition of Calcilox



additive to the fine refuse cake and mixing with the selected



coarse fraction will give satisfactory, immediate handling



characteristics plus long-term stability.   The primary



disadvantage of this approach is the extra cost of sizing



and blending equipment to handle the whole plant reject while



only the fines are the problem.





     4.  Permanent Impoundment Stabilization   (Figure 7)



         Fine refuse slurry is treated with Calcilox additive



and pumped behind an impoundment where it  settles and hardens,



For those companies that already own, or are convinced that



they should construct, lagoons or impoundments for thickener



underflows, we believe that the superior properties of



Calcilox additive stabilized slurries might afford savings



in impoundment construction, and could greatly reduce



abandonment procedures.  Several advantages, tangible and



intangible, for this type of operation could be:



     A.  Reduced initial capital outlay for dam construction.



     B.  Construction costs of the dam might be lower if



         retaining wall structural considerations are used.



     C.  Impoundment would not be holding a fluid, but a



         rigid mass.
                              891

-------
Figure -  7
          PERMANENT IMPOUNDMENT STABILIZATION
                   892

-------
      D.   No devastating fluid mass  movements  could occur.
      E.   The impoundment offers  an  emergency  reservoir  to
          which wastes  can be  dumped conveniently  in the
          event of  an operating emergency  in the preparation
          plant.

Full-Scale  Systems
      In  employing  Calcilox stabilization  of fine  coal refuse,
the overall justification finally becomes one of  economics.
It is very  important to emphasize that many costs associated
with  current disposal  practices are  obscure, since they are
included in other  mine operations.   Secondly, some factors
that  readily affect a  disposal operation  are very intangible
and hard to equate to  dollars  and cents.  Important consider-
ations are  (1) the cost  of maintaining private and public
roads due to slopping  of fine refuse; (2) the time involved
in pulling  equipment out of the muck; (3) low morale due to
bad working  conditions - long hours  in a messy environment
and (4)  the  constant threat of complete facility shutdown due
to regulatory spot checks.  In a complete economic evaluation
of disposal  costs, the above items plus others must be con-
sidered whether Calcilox is being evaluated or not.

     Currently, Calcilox additive stabilization techniques are
in various stages of investigation by numerous companies
representing nearly 60,000 tons per day of cleaning capacity.
Refuse disposal modes under investigation will utilize vacuum
                              893

-------
disc  filter cakes,  solid bowl centrifuge cakes,  and thickener
underflows to meet  the specific objectives of the client com-
panies.   At this  time, three  Calcilox  additive stabilization
systems  are in various stages of final construction,  start-up,
and/or operation.   All three  are treating slurries ranging  from
15% to 45% solids and are employing the interim pond stabilization
method with subsequent dry  landfill disposal with the remaining
plant refuse.  The  following  is an example of one of  these
systems  now in operation (the dollars shown are 1977 dollars).
Example 1:  Disposal Mode - Interim pond disposal with subsequent
           excavation and combination with remaining plant refuse.
           Coal Use - Steam
           Cleaning Capacity - 1300 TPH
           Clean Coal - 1000 TPH
           Fines Disposal Mode - 40 TPH (400  gpm @ 30% solids) as
           thickener underflow and 40 TPH as  filter cake  combined
           with coarse.
           Current Overall Fines Disposal Costs per Ton Clean Coal.  .  $1.52
           Approximate Calcilox System Capital Installed  Cost . . .  $80,000
           Approximate Calcilox Additive Ddsage - 10%
           Estimated Overall Fines Disposal Costs with Calcilox
           Stabilization per ton Clean Coal	$1.13
           Estimated Net Disposal Savings with Calcilox
           Stabilization per ton Clean Coal	$0.39
                                                                 (25%)
           Estimated Calcilox Additive Cost per ton Clean Coal. . .  .  $0.32
                                               thickener underflow only
                                                                 $0.46
                                                         for all  fines
                                 894

-------
     Figure 8, Calcilox Additive System,  depicts the actual



installed treatment system.  Briefly,  the thickener underflow



enters the mix tank installed below a  100 ton Calcilox storage



silo.  The Calcilox is metered into a  waste slurry slipstream



via a prewetting cone with a variable  speed rotary valve.  The



mix tank is equipped with a twin-blade turbine agitator to



quickly disperse the Calcilox throughout the mix tank and to



maintain a uniform solids suspension.   The mix tank is sized



to allow for a 10 to 20 minute retention time for all the



anticipated thickener underflow rates.  The treated slurry is



then pumped to the interim settling ponds for 30 days curing



before excavation and dry landfill disposal with the remaining



plant refuse.  The system is also equipped with various



ancillary devices to maintain uniform tank levels, bulk



Calcilox feed densities, and to assure safe and environmentally



acceptable operation of the system.





     In this brief discussion, Calcilox additive stabilization



technology has been reviewed, stabilization methods presented,



and an actual Calcilox treatment system shown with its



associated costs.  In stating these particular costs and for



estimating others, it should be reemphasized that the justifi-



cation for a Calcilox system involves costs that are tangible



and, to a great extent, intangible.  A valid economic justifi-



cation for Calcilox stabilization should start with a thorough



investigation of your current fine coal refuse disposal costs.
                               895

-------
Figure - 8
        CALCILOX ADDITIVE SYSTEM
              896

-------
Important items that should not be overlooked in evaluating



these disposal costs are: (1) lost or reduced production due



to disposal problems; (2) possible reduction of flocculents



used for additional dewatering in settling ponds/ filters,



or centrifuges; (3) elimination of additional and/or special



equipment needed to maintain the disposal operation; and



(4) possible resale or reclamation of the Calcilox additive



stabilized fine coal refuse.  This last point may be quite



applicable to refuses that possess a net BTU content in



excess of 5000 BTU/lb.   Thus, with all these cost factors



evaluated, a sound economic decision can be made on the



application of Calcilox additive stabilization techniques



for fine coal refuse disposal.
                              897

-------
                  CHEMICAL AND BIOLOGICAL CHARACTERIZATION
                    OF LEACHATE FROM COAL CLEANING WASTES

             R. M. Schuller1, R. A. Griffin1, and J. J. Suloway2
                      -'-Illinois State Geological Survey
                      2Illinois State Natural History Survey
                              Urbana, Illinois
                                  ABSTRACT
     Two coal-cleaning solid wastes—a low sulfur residue (LSR) and a high
sulfur residue (HSR)—from the Illinois Herrin (No. 6) coal member were
characterized mineralogically and chemically.  The chemical solubility,
attenuation by soil, and toxicity of soluble constituents in a series of
aqueous leachate solutions at several pHs were determined.

     The major chemical constituents of the solid residues were Al, Ca, Fe,
K, S, and Si (>1%).  Ba, Cl, F, Mg, Mn, Na, Sr, Ti, and Zn were present at
concentrations between 100 and 10,000 ppm.  Trace metals present in the
residues at concentrations between 10 and 100 ppm included As, Co, Cr, Cu,
Pb, and Ni; 20 additional elements were found at concentrations less than
10 ppm.  Mineralogically the coal-cleaning wastes were similar; both included
illite, kaolinite, quartz, calcite, and Na-Ca feldspars.  The notable
exception was the large pyrite concentration in the HSR.

     Of the 60 chemical constituents determined in the solid wastes, 17 from
HSR and 20 from LSR were found to be soluble enough to exceed recommended
water quality levels within the pH range studied (2.5 - 9.2) and under these
laboratory test conditions.  Most of these were soluble only when the pH was
quite acid.  Three constituents in the HSR leachates  (K, NH4, and 804)
exceeded recommended water quality levels in leachates of all pHs, while no
constituents in the LSR exceeded recommended levels at all pH values.

     The attenuation study employed the dispersed soil methodology using three
widespread Illinois soils of varying character.  Results showed a high degree
of attenuation of the major constituents; however, elution of Mg from the
soils themselves could possibly present the greatest potential for pollution
from land disposal.

     Ninety-six-hour static bioassays were conducted with young fathead
minnows (Pimephales promelas) to determine the toxicity of these wastes
leachate solutions.  Full-strength acidic leachates were acutely toxic and
neutral leachates were relatively nontoxic.   However, acidic solutions of HSR
that were neutralized by dilution were still found to cause mortality.  This
suggests a source of toxicity other than acidity.
                                       898

-------
                          INTRODUCTION




     In the United States almost 3 billion tons of carbonaceous


mineral wastes have accumulated as a result of coal mining


(National Academy of Sciences, 1975).  With the projected increase


in coal as an energy source, the wastes are also projected to


increase.  Of primary concern is the pollution potential of these


accumulations of coal waste.  Regardless of how these wastes are


disposed of, they will eventually be exposed to leaching processes



that may make the soluble constituents available to the environ-



ment.  In the case of pyritic wastes, the pollution potential



increases due to the production of sulfuric acid and its subse-


quent solubilization of metals.  This increased acidity may affect


both the productivity of streams and lakes (Kemmel and Sharpe,


1976) and the fertility of the land around waste disposal sites


(National Academy of Sciences, 1975).



     In order to ascertain the pollution potential of coal refuse,



it is desirable to determine:  (1)  the chemical and mineralogical
                                        t

character of the solid waste, (2) the soluble phase of the solid



waste,  (3) the attenuation characteristics in the environment of


the soluble constituents, and (4) the toxicity to biota of these


soluble constituents.




          Characterization of the Coal Cleaning Wastes


Current Studies



     This project is part of ongoing research by the Illinois


State Geological Survey to characterize coal and coal residues



(Ruch,  Gluskoter, and Kennedy, 1971; Ruch, Gluskoter, and Shimp,



1973; Ruch,  Gluskoter,  and Shimp, 1974; Gluskoter, 1975; and




                                899

-------
  Gluskoter  et  al.,  1977).   Included  in  this work  is  an analysls of
  the  pollution potential of coal  solid  wastes  (Griffin et  al.,  1977)
  The  wastes  being studied  include  liquefaction residues (SRC  and
  H-coal), Lurgi  gasification ashes,  fly ash, water quenched slag,
  high and low  temperature  chars, and high and low sulfur cleaning
  wastes  (gobs).  This report deals with the results  from the  coal
  cleaning wastes and represents a  small portion of the  overall  pro-
  ject.  The  authors reserve the right to revise interpretation  of
  data upon completion of the project.

  Chemical and Mineralogical Characterization
      Two coal cleaning solid wastes—a low sulfur (LSR) and a high
 sulfur residue (HSR)—from the Illinois Herrin (No.  6) coal member
 were characterized  chemically  and mineralogically.   The chemical
 composition of the  two wastes  has been  determined for approximately
 60 constituents (Table 1).  The  major  chemical  constituents  of the
 solid residues were Al, Ca, Fe,  K, S, and  Si  (>I%).   Barium,  Cl,
 F,  Mg,  Mn,  Na,  Sr,  Ti, and  Zn were  present  in the  residues  at  con-
 centrations  between 100 and 1000 ppm.   Trace metals  present in  the
 residues at  concentrations  between 10 and 100 ppm include  AS, Co,
 Cr, Cu,  Pb,  and Ni.
      Mineralogically the coal cleaning wastes are similar; both
 included illite, kaolinite, quartz, calcite, and Na-Ca  feldspars.
 The notable  exception was the large pyrite concentration in the
 HSR.  The mineralogy was determined by X-ray diffraction, scanning
 electron microscope, optical techniques, and chemical methods.

Aqueous Solubility
     The solubility  of constituents in the  residues  was determined
                                 900

-------
Table 1:  Chemical Characterization
          of the Coal Cleaning Waste
Constituent
Ag
Al
As
B
Ba
Be
Br
Ca
Cd
Ce
Cl
Cr
Co
Cu
Cs
Eu
P-
Pe
total
Ga
Ge
Ef
K
La
Lu
Mg
Mn
Mo
Na
Ni
Pb
Solid ash
LSR
0.03
97,008
68
200
400
3
3.2
21,227
<1.8
100
700
78
13
36
15.2
1.5
900
24,813
19
4.1
7.9
17,102
50
0.43
3,859
310
<1
3,635
55
55
content (mg/kg)
HSR
0.20
56,572
13
9.3
300
2
1.2
28,159
<1.4
92
300
45.3
10.3
29
9.6
1.2
1,105
86,157
11
1.2
3.2
9,962
43
0.42
1,869
310
3.2
2,419
48
55
                901

-------
Table 1:  (cont'd)
Constituent
P
Rb
Stotal
0
pyritic
Sulfate
Sb
Sc
Si
Sm
Sn
Sr
Ta
Te
Th
Ti
Tl
U
V
W
Yb
Zn
Zr
Solid ash content (me/kc")
LSR
1,397
200
5,100
4,600
400
2.7
15.2
261,380
8
7.2
79
1.2
2.2
20
8,298
8.0
3.1
39.3
2.9
4.3
500
200
HSR
829
100
108,800
76,100
13,500
0.2
9.1
145,490
6.9
3.3
100
0.8
0.6
13
4,668
8.2
2.9
35.3
2.5
2.1
300
100
        902

-------
by making  10%  aqueous  slurries.  Duplicate  sets of  four slurries
each were  adjusted  to  four  individual pH values over the range of
2.5 to  9.2.  Glass  carboys  (2.5 gal) were employed  as reaction
vessels.   One  of the duplicate sets was equilibrated under an
argon (oxygen- and C02-free) atmosphere and  the other set was equil-
ibrated under  an air (oxidizing) atmosphere.  The pH values were
monitored  and  readjusted to the specified values when necessary.
The slurries were monitored for 3 to 6 months or until the solu-
tion pH remained constant, at which time chemical equilibrium was
assumed.
     Tables 2  and 3 list the elements from  the solid residues that
were soluble enough to exceed recommended water quality levels
under the  laboratory test conditions.  The  analyses were performed
by atomic  absorption and colorimetric techniques (EPA Methods,
197*0.  Table  2 compares the waste leachates at their natural pHs
and under  both types of atmospheres.  Table 3 compares the leachates
at their adjusted acidic pHs.  Only K, NH^, and S04 exceed the
recommended levels in the HSR leachates at  all pHs, while no con-
stituents  of the LSR leachates exceeded recommended levels at all
pH values.  The values listed in Table 3 represent what might be
expected under acid mine drainage (AMD) conditions.  It is unlikely
that AMD would develop for the LSR waste due to its relatively low
sulfur content (0.51)  compared to the HSR waste (10.8%).  However,
AMD did not develop for the HSR waste under the experimental con-
ditions described above, and Table 3 represents only the result
of adjusting the leachate pH with nitric acid.   The concentrations
in solution obtained by this adjustment fall well within the range
of values others have  reported for typical AMD  affected streams
                                903

-------
Table 2:  Constituents Exceeding Recommended Water Quality Levels
          in the Natural pH Supernatents under the Laboratory
          Conditions (concentration in mg/1)                y
Low Sulfur Residue High Sulfur Residue
Air Argon Air Argon
Constituent pH 8.6 8.5 7.5 7.4
Al 4.4 0.62 —
B 1.0 1.0
Ca — — 480 590
F 1.7 1-7 1.4 1.4
K — -- 11.9 15.5
Mn — 0.07
NH4 — — 0.3 1.5
Pb 0.15 ~ 0.2 0.15
POjj 0.08 0.06
SOjj — — 1600 1500
	 • 	 	 	 . — . —
Recommended
Water Quality
Levels 	
0.1
0.75
50
1.0
5.0
0.05
0.02
0.03
0.05
250
                                 904

-------
Table 3:  Constituents Exceeding Recommended Water Quality Levels
          in the Most Acid pH Supernatents under the Laboratory
          Test Conditions (concentration in mg/1)
Low Sulfur Residue
Constituent
Al
Ba
Ca
Cd
Cr
Co
Cu
Fetotal
K
Mg
Mn
NH4
Ni
Pb
P04
SOj,
Zn
Air
pH 2.5
29.0
1.9
2595
0.09
0.06
0.64
1.68
130
38
119-7
24.4
4.5
1.06
0.50
3.0
—
1.55
Argon
pH 2.4
57.0
2.5
2784
0.09
0.13
0.48
1.34
360
40
138.9
30.7
4.9
—
0.70
44.0
—
1.40
High Sulfur Residue
Air
pH 2.6
27-6
—
2310
—
0.09
0.90
—
205
19
68.7
17.4
3.8
1.45
0.40
2.0
1300
3-7
Argon V
PH 2.5
35.3
—
2305
--
0.07
0.82
—
275
20
70.4
18.0
4.2
1.57
0.50
13.5
1400
3.1
Recommended
tfater Quality
Levels
0.1
1.0
50
0.01
0.05
0.05
0.2
0.3
5
50
.05
.02
1.0
0.03
0.05
250
0.2
                                 905

-------
(Wllmoth, 1972; Hanson, 1972; and Gang and Langmuir,  197/1).   The
most probable explanation is inadequate oxidation due to the slow
diffusion rate of air through water in the 2% gallon  carboys
employed.  Other possible explanations are the lack of ferric iron
in solution as a pyrite oxidizer and insufficient development of
bacterial activity.
     It is difficult to explain the aqueous chemistry of a complex
system such as the coal refuse leachates.  Possible complexation,
ion pair formation, and the effects of organic components on the
formation of organometallic complexes hinders the description of
these systems.  However, it is still of Interest to examine them
in an effort to account for their soluble components, and of most
interest is the iron and sulfate chemistry.
     Figure 1 is a plot of the Ca2* and SO^ ion activities for
the two aerated leachate systems.  The plot indicates that  while
the LSR leachates are undersaturated with respect to  gypsum/ann-
hydrite, the HSR leachates are slightly supersaturated in all but
the most alkaline case.  However, because of the range of error
in sulfate analyses and the use of solubility products calculated
for pure CaSOi, systems, it is quite possible that the HSR leachates
are within the range of saturation and are indeed in chemical
equilibrium with annhydrite.  Further calculations show that Ba
and Sr in the LSRvleachates are undersaturated with respect to
their sulfate compounds with approximately 100? of the Ba and Sr
in the solid waste being in solution.  The HSR solutions are also
undersaturated with respect to SrSOi+j where approximately 50?f of
the available Sr in the refuse is in solution.
     Figure 2 is an Eh vs. pH diagram displaying the stability
relations of iron oxides and sulfides in water  (Garrels and Christ,
                                906

-------
                                                                  -0
Supersaturated
          Undersaturated
                           -loga  SO4=


Figure 1:   Plot of calcium sulfate  solubilities for aerated HSR
           and LSR.
                                907

-------
 +1.2-
         O HSR  Air
         A HSR  Argon
         • LSR  Air
         A LSR  Argon
  -0.8
Figure 2:   Stability relations of iron oxides and sulfides in
           water at 25°C when ES=10~3  molar  (native sulfur field
           excluded).
                                908

-------
1965).  There is a strong agreement between the Eh-pH values
plotted for the leachates and the Fe2  concentrations that were
measured experimentally.  However, it is of interest to note that
the leachate systems (under both air and argon) are in the Fe2+-
hematite stability range.  This indicates that the leachate sys-
tems are not in equilibrium with pyrite.  The reason for the lack
of equilibrium is the slow rate of pyrite dissolution (oxidation)
as discussed above.

Attenuation Study
     The traditional approach to studying earth material attenua-
tion of leachates or waste effluents has been experimentation using
soil column leaching.  Rovers, Mooij, and Farquhar (1976) have
shown that a dispersed soil methodology or batch reactor technique
was suitable to approximate the behavior of contaminants of liquid
industrial wastes in soils at a considerable savings in time and
expense over soil column leaching studies.
     The dispersed soil method has been shown to produce similar
results to both remoulded and undisturbed column leaching studies
(Rovers, MooiJ, and Parquhar, 1976).  The technique involves mix-
ing a known volume of leachate with a known weight of soil brought
to field moisture capacity.  This is repeated five times in series
with portions of leachate being drawn off and filtered for analy-
sis.  Figure 3 is a schematic diagram of the methodology.
     Three Illinois soils, Ava slcl., Catlin sil., and Bloomfield
Is., having a range of physical and chemical characteristics were
collected and characterized for use in this study.  Table 4 gives
some of the pertinent characteristics of these soils.
                                909

-------
                    Addition of waste effluent followed
                          slugs of  desorption water
VO
t->
O
R
e
a
c
t
o
r
R
e
a
c
t
o
r
R
e
a
c
t
o
r
R
e
a
c
t
o
r
R
e
a
c
t
o
r
                                                                             soil
                                    allquots for chemical  analysis

                    Figure 3:  Schematic diagram of dispersed soil methodology,

-------
Table 4:  Soil Characteristics
Soil
Catlin
silt loam
Ava
silty clay
Bloomfield
loamy sand
pH
7.1

4.5
loam
5.7

CEC
(meq/lOOg)
18.1

13-1

0.8

Surface
Area, N~
(m2/gr
10.1

28.3

1.7

Organic
Carbon
(*)
4.73

1.18

0.21

Sand
(*)
11.6

2

82

Silt
(*)
60.9

69-6

10

Clay
(*)
27.2

28.4

8


-------
       Only  the  natural  pH  supernatents  are  reported  (LSR, pH  8.64
  and  HSR, pH  7-46).   The filtrates  from the attenuation  study were
  analyzed for Al, B,  Ca, Fe, K, Mg, Mn,  Na, SO^, and Zn.  These ten
  constituents were determined because they were present  in the
  leachates  In sufficient concentration  to present a potential pol-
  lution hazard  due to leaching through  soil.
      Mechanisms of attenuation for the  leachate constituents
  include adsorption, ion exhcange, complexatlon, precipitation,
  oxidation-reduction and many physical and biological mechanisms
  such as filtering and degradation.   Usually attenuation in a com-
 plex system is a result of not just one but several of these pos-
 sible mechanisms (Phillips and Nathwani, 1976).   In general  adsorp-
 tion and precipitation are the principal mechanisms for removal of
 organic constituents.   Also,  the  higher the clay  and/or organic
 content of  a  soil  the more effective  the material  is  as an atten-
 uating medium.
      Tables 5 and  6  list the results  of the attenuation  analyses.
 The  LSR leachate-soll  mistures resulted in  elution  of  Ca, K,  and
 Mg from the three  soils and Mn from the Ava soil.   Only  Na was
 consistently  removed  from  solution.  The HSR  leachate-soil mixtures
 (Table  6) also  resulted in elution  of Mg but  to a lesser extent
 and again elution of Mn from the Ava soil.  All other  constituents
 were  attenuated.
      The overall attenuation and elution  of potential  contaminants
 for the mixtures follows the same trend  as the cation  exchange
capacity of  the soils:  Catlin >_ Ava >  Bloomfield.   However, it
is doubtful that exchange  is the only mechanism responsible for
                                              rt
removal. In the HSR leachate-soil mixtures,  Ca * and SO4* are in

                               912

-------
Table 5:  Results of Attenuation Analysis for LSR Including
          Original Leachate Concentrations81
Constituent
pH
ECb
Ca
K
Mg
Mn
Na
so4
Waste
leachate
8.6
0.74
1.8
3.8
4.6
<.03
200
112
Ava
4.2
0.36
5-5
5-6
113-0
0.33
36
44
Bloomfield
6.7
0.62
20.7
9.9
70.4
<.03
104
102
Catlin
6.9
0.73
47.5
6.6
231.0
<.03
17
139
Concentrations in mg/1

 millimhos/cm
                            913

-------
Table 6:  Results of Attenuation Analysis for HSR Including
          Original Leachate Concentrations+a
Constituent
pH
ECb
Ca
K
Mg
Mn
Na
S04
Waste
leachate
7.5
2.40
612
1.5
31.8
<.03
192
2254
Ava
4.0
0.87
69
0.9
56.8
1.2
65
305
Bloomfield
7.3
1.87
392
1.6
42.9
<.03
106
1203
Catlin
6.8
1.38
282
1.0
58.9
• <.03
27
644
o
 Concentrations in mg/1

 millimhos/cm
                            914

-------
solution In saturation with respect to CaSOit'2H20 (gypsum), which
would indicate that their steady decrease in concentration through
the reactor series is due to precipitation of gypsum.  Due to the
high ratio of leachate employed to soil moisture content, dilution
is not considered to be a significant mechanism of removal.
Toxicity Studies
     Ninety-six hour static bioassays were conducted with young
fathead minnows (Plmephales promelas) to determine the toxicity of
these waste leachate solutions.  The toxicity tests were divided
into two phases:  the screening procedure and the LC-50 determina-
tion.  During the screening procedure, the young fathead minnows
were exposed to the full-strength leachates; in the LC-50 determin-
ations, the minnows were exposed to full-strength leachates diluted
with soft reconstituted water prepared as suggested in "Methods
for Acute Toxicity Tests with Pish, Macroinvertebrates, and Amphib-
ians" (The Committee on Methods for Toxicity Test with Aquatic
Organisms, 1975).  Procedures outlined in Litchfield and Wilcoxon
(1949) were used for LC-50 determinations.
     Ten young fathead minnows were placed Into glass fingerbowls
(115 x 45 mm) containing 200 ml of full-strength or diluted lea-
chate.  Each bioassay was replicated.  Fish mortality data were
collected at 24, 48, 72, and 96 hours after the bioassays were
begun.  The test organisms were not fed and the solutions were not
aerated during the bioassays.  Since one-half of the leachates
were equilibrated under anaerobic conditions, all solutions were
aerated before the fish were added.  The bioassays were conducted
at a constant temperature (21° + 1°C) and with a constant photo-

                                915

-------
period (16L-8D) in an environmental chamber.   At the beginning and
end of all bioassays, pH and dissolved oxygen readings, were taken.
Specific conductance was measured at the beginning of each bio-
assay.
     The results of the screening procedure are depicted in Figure
4.  Leachates of neutral pH (6.8 - 8.0) are relatively nontoxic.
Total mortality occurs in acidic (pH <6.2) solutions.
     The LC-50 values, their 95 percent confidence intervals, and
dilutions necessary to eliminate mortality are listed in Table 7-
The pH values listed are the pHs of full-strength leachates after
they were aerated and before they were diluted with reconstituted
water.  There is an inverse relationship between toxicity and the
LC-50 value.  For example, the LC-50 values for HSR3 and HSR^ are
41.00 and 3.00, respectively (Table 7).  Forty-one milliliters of
HSRs diluted with 59 ml of reconstituted water is as toxic as 3.00
of HSRi+ diluted with 97 ml of reconstituted water.  Thus, leachates
exhibiting greater toxicity have lower LC-50 values than less toxic
leachates.  If, in full-strength solutions, less than 50$ mortality
occurred, the LC-50 is reported as greater than 100 ml/100 ml.
     Generally, all leachates are acutely toxic when acidic  (pH
«6.2) and with increasing acidity there is an increase in toxicity
and a decrease in the LC-50 value.  The natural pH leachates  (LSRj,
LSR5, HSR2, and HSR6) are not acutely toxic and do not require a
dilution to eliminate mortality (Table 7).  The LC-50 values  for
anaerobic leachates are not significantly different from sililar
aerobic solutions (p <.05, paired t-test).
     Many factors probably contribute to the acute toxicity  of
the acidic leachates.  It has been shown  (Griffin et al., 1977)
                                916

-------
100-1
           on*
 80-
>.60-
o
 40-
 20-
• HSR  Argon

O HSR  Air

• LSR  Argon

D LSR  Air
             T
              3
               "T
               4
T
 5
T
 7
8
                                         pH
T
 9
-I
 10
           Figure 4:   Plot of percent mortality vs. pH for HSR and LSR leachates

-------
         Table 7:  LC-50 Values  for LSR and  HSR  Leachates
Sample
*LSR1
LSR2
LSR3
LSR4
*LSR5
LSR6
LSR?
LSRg
HSR1
*HSR2
HSR3
HSR4'
HSR5
*HSR6
HSR?
HSRg
u
Atmosphere
aerobic
aerobic
aerobic
aerobic
anaerobic
anaerobic
anaerobic
anaerobic
aerobic
aerobic
aerobic
aerobic
anaerobic
anaerobic
anaerobic
anaerobic
pH
8.8
7.9
5.4
3.8
8.9
7-7
6.6
4.0
8.1
7.7
3.5
2.7
8.0
8.0
3.9
2.6
LC-50
ml/100 ml
>100
>100
57-00 + 2.28
3.80 +_ 0.41
>100
>100
96.00 + 0.83
2.15 + 0.16
>100
>100
41.00 +_ 2.87
3.00 + 0.62
>100
>100
56.00 + 2.52
2.30 + 0.14
Dilution for
zero mortality
1:1
1:1
1:3
1:50
1:1
1:1
1:1
1:100
1:1
1:1
1:4
1:67
1:1
1:1
1:2
1:67
Natural pH
                                918

-------
that reconstituted water of low pHs (pH <5.9) will cause total



mortality.  Since the young fathead minnows were propagated and



held at pH 7.4 and experienced a rapid change in pH, the mortality



was partially due to "ionic shock."  However, some acidic solutions



of HSR that were neutralized by dilution were toxic.  Upon neutral-



ization, a ferric hydroxide precipitate was formed; this precipi-



tate adhered to the mucus of the gills and resulted in suffocation.



Mortality, reduced fry survival, slower growth, and reduced hatch-



ability have been observed in other investigations of the effects



of ferric hydroxide precipitates on fish (Sanborn, 19^5; Sykora



et al., 1972; and Smith et al., 1973).



     The effects of other constituents are more difficult to assess.



Although the concentrations of most of the constituents are far



below LC-50 values established in previous studies for single con-



stituents (Eaton, 1973; Pickering, 1974; and Pickering and Gast,



1973)> these constituents could act synergistically and thus would



contribute to the acute toxicity of the acidic leachates.  The natu-



ral pH leachates are not acutely toxic; however, the chronic toxic-



ity of these leachates has not been examined.  Single constituents



such as Ca, K, Pb, and Mn, which are found in relatively high but



not acutely toxic concentrations in the natural pH leachates,



could be chronically toxic when acting synergistically.





                             SUMMARY



     The pollution potential from the disposal of coal cleaning



wastes is of concern, if not because of the nature of the waste



then because of the enormous quantity of the waste generated.  In



order to evaluate this pollution potential it is necessary to char-



acterize both the solid waste and the leachate that it is capable




                               919

-------
of generating.  It Is then necessary to determine how the constit-
uents can be removed from the leachate and how these constituents
will effect the biota If they are not removed.
     The study of two Illinois coal cleaning wastes has shown that:
1.  Contamination from the wastes Is most severe under acid condi-
    tion.
2.  Land disposal of the wastes may result in pollution by elution
    of contaminants from the soils themselves.
3.  Toxiclty to biota is not a function of acidity alone, but may
    also be due to the formation of precipitates during neutrali-
    zation.

                         ACKNOWLEDGEMENTS
     We gratefully acknowledge the U.S. Environmental Protection
Agency, Energy Assessment and Control Division, Fuel Process Branch
Research Triangle Park, North Carolina, for partial support of this
work under Contract 68-02-2130, Characterization of Coal and Coal
Residue.
     The authors wish to thank S. J. Russell, A. A. Debus, and the
Analytical Chemistry Section of the Illinois State Geological Sur-
vey, under the direction of Dr. R.  R.  Ruch, for assistance in por-
tions of this research.
                                920

-------
                           REFERENCES


Eaton, J. G.  1975-  Chronic toxiclty of a copper, cadmium, and
     zinc mixture to the fathead minnow (Pimephales promelas) .
     Wat. Res. 7:1723-1726.

Gang, M. W. , and D. Langmuir.  1970.  Controls of heavy metals  in
     surface and ground waters affected by coal mine drainage.
     Clarion River - Red Bank Creek Watershed, Pennsylvania, Fifth
     Symposium on Coal Mine Drainage Research, Louisville, Kentucky,
     pp. 3-70.

Garrels, R. M. , and C. Christ.  1965.  Minerals, solutions and
     equilibria.  Harper and Row, New York.

Gluskoter, H. J. 1975.  Mineral matter and trace elements in coal,
     in Babu, ed., Trace Elements in Fuel, Advances in Chemistry
     Series 1^1, American .Chem. Soc.  p. 1-22.
Gluskoter, H. J. ,  R. R. Ruch, W. G. Miller, R. A. Cahill, G. B.
     Dreher, and J. K. Kuhn.  1977.  Trace elements in coal:  Occur-
     rence and distribution.  Illinois State Geological Survey Cir-
     cular
Griffin, R. A., R, M. Schuller, J. J. Suloway, S. J. Russell, W.
     F. Childers, and N. F. Shimp.  1978.  Solubility and toxicity
     of potential pollutants in solid coal wastes.  EPA-6QO/7-78-
     063, April (1978).  Environmental Protection Technology Series

Hanson, P. J. 1972.  Foam separation of metals from acid mine
     drainage.  Fourth Symposium on Coal Mine Drainage Research,
     Pittsburgh, Pennsylvania,  pp. 157-179.

Kimmel, W. G., and W. E. Sharpe .   1976.  Acid drainage and the
     stream environment.  Trout 17(1): 21-5.

Litchfield, J. T., Jr., and F. Wilcoxon.  19^9.  Simplified method
     of evaluating dose-effect experiments.  J. Pharm. Exp. Thes.
     96:99-113.

Methods for acute toxicity tests with fish, macroinvertebrates, and
     amphibians.  1975.  Committee on Methods for Toxicity Tests
     with Aquatic Organisms, National Water Quality Labs., EPA,
     Duluth, MM, EPA-660-3-75-009, P. B. 0 242-105/AS.

National Acadamey erf Sciences.  1975.  Underground disposal of coal
     mine wastes.  Report to the National Science Foundation,
     Washington, D.C.

Phillips, C. R., and J. Nathwanl.  1976.  Soil waste interactions:
     A state of the art review, report EPS 3-EC-76-14, Environment
     Canada, October (1976)

Pickering, Q. H.  1971*.  Chronic toxicity of nickel to the fathead
     minnow.  J. Wat. Poll. Cont . Fed. 46:760-766.

                               921

-------
 Pickering,  Q.  H.,  and  M.  H.  Gast.   1972.   Acute  and  chronic  tox-
      icity  of  cadmium  to  the fathead  minnow  (Plmephales promelas).
      J.  Fish.  Res.  Bd.  Can.  29-1099-1106.

 Rovers,  F.  A.,  H.  Mooij,  and G. J.  Farquhar.   1976.  Contaminant
      attenuation - Dispersed soil  studies.   EPA-600/9-76-015,
      July  (1976).   pp.  224-234.

 Ruch, R. R., H. J.  Gluskoter, and  E.  J. Kennedy.   1971.  Mercury
      content of Illinois  coals.  Illinois  State  Geological Survey
      Environmental Geology Note 43, 15 p.

 Ruch, R. R. , H. J.  Gluskoter, and  N.  F. Shimp.   1973.  Occurrence
      and distribution  of  potentially  volatile  trace  elements in
      coal:  An  interim  report.  Illinois State Geological Survey
      Environmental  Geology Note 6l, 43 p.

 Ruch, R. R., H. J.  Gluskoter, and N.  F. Shimp.   1974.  Occurrence
      and distribution of  potentially  volatile  trace  elements in
      coal:  A final report.   Illinois State Geological Survey
      Environmental  Geology Note 72, 96 p.

 Sanborn, N. H.  1945.  The Lethal effect of certain  chemicals on
      freshwater fish.  Canning Trade  67, (49):   10-12 and 26.

 Smith, E. J., J. L. Sykora,  and M.  A.  Shapiro.   1973.  Effect of
      lime neutralized iron hydroxide  suspensions on  survival,
      growth and reproduction of the fathead minnow.  J. Fish. Res
      Bd. Can. 30:1147-1153.

 Sykora, J.  E., J.  Smith, M. A. Shapiro, M.  Synab.  1972.   Chronic
     effect of ferric hydroxide on certain species of aquatic
     animals.  Fourth Symposium on Coal Mine Drainage Research,
     Pittsburgh, Pennsylvania,  pp. 347-370.

U.S. Environmental Protection Agency.   1974.   Methods for Chemical
     Analyses of Water and Wastes,  EPA-625/5-74-003.

Wilmoth, R.  C., D.  G.  Mason,  M.  Gupta.  1972.  Treatment  of fer-
     rous iron acid mine drainage  by reverse  osmosis.  Fourth
     symposium on Coal  Mine Drainage Research, Pittsburgh,  Penn-
     sylvania,   pp. 115-157.
                               922

-------
                    INTRODUCTION TO CHEMICAL COAL CLEANING

                                R. A. Meyers
                           TRW Systems and Energy
                         Redondo Beach, California
                                INTRODUCTION


     Some specific methods for the chemical removal of sulfur  from coal  are
going to be presented in this symposium.   I will attempt  to  present a  statement
of the problem associated with finding effective and economic  routes to  the
desulfurization of coal, indicate some of the pitfalls of experimentally
investigating sulfur removal in coal and  present a very recent example of
removal of both inorganic and organic sulfur from the same coal.   I plan to
emphasize the removal of organic sulfur from coal as there are now several
methods for removal of pyritic sulfur, but, in my opinion, no  certain  method
for the removal of organic sulfur has been published to date other than
hydrogenation under coal liquefaction conditions.

     Many of the figures will be taken from my book Coal  Desulfurization,
                                                   '-^
which was recently published by Marcel Dekker, Inc.-   and the experimental
examples are from our laboratories.

     This presentation will consist of four sections:   coal molecular structure
and reactivity, sulfur removal mechanisms, criteria for economic success and
an example of chemical removal of both pyritic and organic sulfur to potentially
meet the revised NSPS requirements.
                                     923

-------
 COAL MOLECULAR STRUCTURE
      A model  of the organic coal  matrix,  proposed  by  G1venv  '  1s  shown 1n
 Figure 1.  Given later assessed  the available  knowledge  on  the structure
 of the organic sulfur units present 1n  coal, concluding  that mercaptans,
 sulfldes, dlsulfldes and thlophenes were  the major organic  sulfur containing
                  (3)
 functional  groupsx  '.   The  Inorganic portion of  coal  consists  of a vast
 number of minerals  1n discrete agglomerations  and often  Intimately associated
 with the organic coal  matrix.  The  Inorganic sulfur 1n coal occurs mainly
 as the mineral  pyrlte with  small  amount of  Inorganic  sulfate minerals such
 as melanterUe,  jaroslte and gypsum.

      These  Inorganic forms  can be removed either partially or  totally by a
 number of published  methods, some of which will be presented at this sym-
 posium.   The  removal  of the organic  sulfur has proved to be very difficult,
 as the compounds  are not just Intimately associated with the organic coal
 matrix,  they  are  chemically bonded  Into the core of the carbon structure.
 Removal  of  these  compounds  necessarily  requires a partial breakdown of the
 organic  coal  matrix.

 SULFUR REMOVAL MECHANISMS
      Potential methods  for  the removal of organic sulfur from coal have
 been  classified Into six groups as shown 1n Figure 2.a-c.  These are:
 solvent  partition, thermal  decomposition, add base reaction, reduction,
 oxidation and displacement.   These mechanisms all have the common feature
 of being potentially capable of  removing the organic  sulfur content of
 coal as small  soluble or volatile molecules, containing a prepondance of
sulfur.  Of these mechanisms, only reduction (with  hydrogen) has been
clearly shown to be effective up  to  the  present     ^  '
                                   924

-------
vC
fO
Ul
               H2
            H2
                       SH
CH,     H2
                                        FIGURE 1.  MODEL OF ORGANIC COAL MATRIX

-------
                         1.  SOLVENT PARTITION
                                  1  X  7"*" ^ ~"*
                R1

                R2
SX    X
(Eq. 6)
VO
10
                         2. THERMAL DECOMPOSITION
                                  i Sv Ro  A
RCH2 CH2  SH    RCH = CH  + H
                                                                       (Eq. 81
                            FIGURE 2.a.  ORGANIC SULFUR REMOVAL MECHANISMS

-------
VO
to
               3.   ACID-BASE  NEUTRALIZATION
                          RSH + OH"  -   RS" + H20
               4.   REDUCTION
R,SXR2 + 4H  - R,H + R2H
R,SXR2
             H2  -  R,H
                                             (Eq. 9)
                                                                       (Eq. 10)

                                                                       (Eq. II)
                      FIGURE 2.b.  ORGANIC SULFUR REMOVAL MECHANISMS (Continued)

-------
vo
K3
OO
                   5.   OXIDATION                       H 0
        RISXR2  ~"  R| S03H + R2 S03 H  -  R, OH + R2 OH + 2H2 S04    (Eq. 12)



6.   NUCLEOPHILIC  DISPLACEMENT

        R|SXR2 + Nu"   -  R,SX Nu + R2~            (Eq. 13)


        R|SXR2 + Nu"   -  R,SX_, Nu + R2S"         (Eq. 14)


        R,SXR2 4 Nu"   -  R,SX" + R2 Nu            (Eg. 15)


        R2S" + R,SX_, Nu  -    R|SX-|R2 + Nu S"
              TAKEN FROM:  R. A. MEYERS, COAL DESULPJRtZATION, MARCEL DEKKER, INC. (1977)
                            FIGURE 2.c.  ORGANIC SULFUR REMOVAL MECHANISMS (Continued)

-------
      Potential  pyrlte  removal  reactions have also been categorized.  These
 Include:   displacement,  add  base  neutralization, oxidation and reduction^1).
 Of these,  only  the  displacement mechanism has not been demonstrated.
 CRITERIA  FOR  SUCCESSFUL  CHEMICAL DESULFURIZATION PROCESSES
      The major  criteria  for economic removal of either Inorganic or organic
 sulfur  from coal are shown 1n  Figure 3.  The desulfurlzatlon reagent must
 be selective  and not significantly react with other coal components.  The
 reagent should  be regenerable  and be either soluble or volatile so 1t can
 be recovered  from the  coal matrix.  Finally, the reagent should be Inexpensive
 since a portion of  1t  will certainly be lost to either Irreversible sorptlon
 on the  coal matrix  or  by reaction.

 AN EXAMPLE OF REMOVAL  OF BOTH  PYRITIC AND ORGANIC SULFUR FROM THE SAME COAL
      One of the methods discussed 1n Coal  Desulfurlzatlon^ was examined
 experimentally  In our  laboratories for removal  of both pyrltic and organic
 sulfur  from a high  sulfur coal.  A well characterized sample of Kentucky
 No. 9 seam coal  was selected for the substrate as 1t contained a total of
 6.8 Ib  of S02/106 Btu  of which half was Inorganic and half organic (Figure
 4  - Example 1).   Treatment of this coal for 30 minutes results 1n removal
 of 38+15% of  the organic sulfur and a large part of the pyrltic sulfur
 (Example 2).  However, these results were  actually not particularly
 encouraging as the organic sulfur removal, even at "38X", Is only barely
 significant 1n view of error associated with analysis.  Further, the re-
maining total  sulfur level  of 2.3 Ib S02/106 Btu 1s not close to meeting
 federal standards.
                                     929

-------
to
REAGENT SELECTIVITY TOWARD SULFUR COMPOUNDS IN COAL
REGENERATION TO THE INITIAL FORM
SOLUBLE; VOLATILE OR OTHERWISE RECOVERABLE REAGENTS
 AND PRODUCTS
INEXPENSIVE - SOME LOSS INEVITABLE
                 FIGURE 3.  CRITERIA FOR SUCCESSFUL CHEMICAL DESULFURIZATION PROCESSES

-------
Example
1
2
3
4
Coal
Run-of-Mlne
Run-of-Mlne
Gravl -Float
Grav 1- Float
Treatment
None
Yes
None
Yes

st
6.8 +0.4
2.3 + 0.3
3.2 +0.3
0.8 + 0.4
Sulfur Content, lb/106 Btu
SP Ss
3.1 +0.2 0.6 +0.2
0.3 + 0.2 0.1 + 0.2
0.2+0.2 0.3+0.2
0.2 + 0.2 0.0 + 0.2

So
3.1 +0.3
1.9 + 0.3
2.8+0.3
0.6 +0.3
Organic
Sul fur
Removal

38X +15%

77% + 17%
30-mln extraction time
                     FIGURE 4.  ORGANIC SULFUR REMOVAL FROM KENTUCKY NO.  9 COAL*

-------
     Analysis of the coal ash Indicated that there was significant reaction
of the selected reagent with the mineral component of the coal.  Therefore,
1t was decided to Investigate the desulfurlzatlon reaction on "gravl-float"
coal which Is extremely low In ash.  Gravl-float coal Is obtained by float-
sink separation of coal In Iron sulfate leach solution at specific gravity
1.3-1.4, followed by washing with water to remove residual sulfate and
additional ash.  The resulting coal (Example 3) has an ash content of only
3-4X, whereas the run-of-mlne Kentucky No. 9 coal has an ash content of
about 125L  Further, there Is essentially no pyrlte 1n the coal.   Thus, the
chances for consumption of the reagent by reaction with the mineral  matter
Is greatly reduced.
                                 *
     Indeed,  treatment  of gravl-float coal under conditions Identical  to
those of the run-of-m1ne coal  (Example 4) resulted 1n removal  of  77+17X of
the organic sulfur and a total  sulfur content of 0.8 Ib S02/10 Btu.   This
corresponds to an overall 85* reduction In sulfur content starting with run-
of-mlne coal.  There are a number of parameters which must be evaluated to
allow economic assessment.  These Include:  reagent loss, coal recovery,
energy balance, etc.  Thus, a good deal  of bench-scale experimentation and
engineering and economic evaluation Is needed before this method  can  be
considered for meeting New Source Performance Standards.  However, the
results obtained to date Indicate that It may be possible to meet standards
by pretreatment of coal.
                                        932

-------
                            REFERENCES

1,  Meyers,  R, A,  Coal DesulfuHzatlon,   Marcel  Dekker, Inc., New York,
    1977.
2.  Given,  P.  H,  Fuel.  39:147, 1960.

3.  Given,  P.  H. and W. F. Wyss.  Brit.  Coal  Utilization Research Association
    Monthly Bulletin.  25:165, 1961.

4.  Meyers, R, A,, J.  W. Hamersma, R. M. Baldwin, J.  G. Handwerk, J. H. Gary
    and 0.  0.  Golden.  Energy Sources.  3(1):13, 1976.
                                  933

-------
                      CURRENT STATUS OF CHEMICAL COAL
                     CLEANING PROCESSES - AN OVERVIEW

                   L. C. McCandless and Mrs. G. Y. Contoa
                               Veraar, Inc.
                           Springfield, Virginia
                                  ABSTRACT
     A variety of chemical coal cleaning processes are under development which
will remove a ma.loritv of pyritic sulfur from coal with acceptable heating
value recovery, i.e., 95 percent Btu recovery.  Some of these processes are
also capable of removing organic sulfur from the coal, which is not possible
with physical coal cleaning methods.  Chemical coal cleaning processes at the
bench scale level have demonstrated removal of as much as 95 to 99 percent
of pyritic sulfur and up to about 40 percent of the organic sulfur from the
run-of-mine coal.  It is projected that this removal efficiency could result
in total  sulfur reductions in U.S. coals in the range of 53 to 77 percent.

      This paper presents available technical and  economic information on major
U.S.  chemical  coal cleaning processes  identified  during an eight-month  study,
conducted for  the Industrial Environmental Research Laboratory of EPA at
Research  Triangle Park,  North  Carolina.
                                       934

-------
1.0  INTRODUCTION
     What role should Chemical Coal Cleaning Processes play in
the scenario of maximizing coal utilization without environmental
deterioration?  The National Energy Policy and the 1977 Clean
Air Act Amendments require that more coal be burned, but with
reduced sulfur emissions.
     The current options for decreasing sulfur emissions from
the combustion of coal are:
     •  pretreatment fuel processing including physical and
        chemical coal cleaning;
     •  synthetic fuels production;
     •  fluidized bed combustion; or
     •  post-combustion control technology, namely flue gas
        desulfurization.
Only flue gas desulfurization and physical coal cleaning are
commercially available.
                                935

-------
     Physical coal cleaning can remove 60 to 90 percent of the

pyritic sulfur or some- 40 to 70 percent of the total sulfur in

the raw coal, but cannot remove the organic sulfur„  However,

one problem with mechanical "deep" coal cleaning is that carbon

values (BTU's) are removed with the sulfur and ash, which can

result in rejecting as much as 40 percent of the total energy

value of the coal.

     Chemical coal cleaning processes, now being developed,

remove as much as 95 percent of the mineral sulfur and up to

about 40 percent of the organic sulfur.  This results in

removal of some 50 to 80 percent  of the total sulfur in the

raw coal.

     Twenty-nine chemical coal cleaning processes were identified

during an eight month technology  overview study conducted for

the Industrial Environmental Research Laboratory of EPA at

Research Triangle Park, North Carolina.  Eleven U.S. developed

processes were classified as major processes during this study,,

This paper presents  a summary of  available  technical and

economic information on  these processes'based  upon Versar's

assessment,  conceptual designs and costing.

2oO  SUMMARY OF  TECHNICAL AND COST INFORMATION FOR MAJOR
     CHEMICAL COAL  CLEANING PROCESSES

     Table  1 shows  a listing of  the  major processes-   The  first

 four processes listed (Magnex,  Syracuse,  TRW,  and  Ledgemont)

will remove  pyritic sulfur  only;  the remaining seven processes
                                 936

-------
TABLE 1.  SUTIARY OF MAJOR CHEMICAL COAL CLEANING PROCESSES
PROCESS S
SPONSOR


"MAGNEX",®
HAZEN RESEARCH
INC,, GOLDEN
COLORADO


"SYRACUSE"
SYRACUSE
RESEARCH CORP,,
SYRACUSE, N.Y,

"MEYERS", TRW,
INC, REDONDO
BEACH, CAL,


"LOU' KENNECOTT
COPPER CO,
LEDGEMONT, MASS,


METHOD


DRY PULVERIZED COAL
TREATED WITH FE
(C0>5 CAUSES PYRITE
TO BECOME MAGNETIC.
MAGNETIC MATERIALS
REMOVED MAGNETICALLY
COAL IS COMMINUTED
BY EXPOSURE TO NH3
VAPOR; CONVENTIONAL
PHYSICAL CLEANING
SEPARATES COAL/ASH
OXIDATIVE LEACHING
USING FE2(S04)3 +
OXYGEN IN WATER


OXIDATIVE LEACHING
USING Oj AND WATER
8 MODERATE TEMP.
AND PRESSURE
TYPE SULFUR
REMOVED


UP TO 90%
PYRITIC



50-705
PYRITIC


90-95%
PYRITIC


90-95%
PYRITIC


STAGE OF
DEVELOPMENT
-l

BENCH & 91 KG/DAY
(200 LB/DAY) PILOT
PLANT OPERATED



BENCH SCALE


8 METRIC TON/DAY
PDU FOR REACTION
SYSTEM. LAB OR
BENCH SCALE FOR
OTHER PROCESS
STEPS.
BENCH SCALE




PROBLEMS


DISPOSAL OF S-CONTAIN-
ING SOLID RESIDUES.
CONTINUOUS RECYCLE OF
CO TO PRODUCE FE
(C0)5 REQUIRES
DEMONSTRATION
DISPOSAL OF SULFUR
CONTAINING
RESIDUES.


DISPOSAL OF ACIDIC
FES04& CAS04, SULFUR
EXTRACTION STEP
REQUIRES DEMONSTRA-
TION
DISPOSAL OF GYPSUM
SLUDGE. ACID
CORROSION OF
REACTORS
ANNUAL OPERATING
COST $/TON CLEAN
COAL INCLUDING
COST OF COAL
40.7



37.0


43.4


4R q
HO. j


  RAW COAL COST IS INCLUDED AT $25/TON.

-------
(ERDA, GE, Battelle, JPL, IGT, KVB, and ARCO) claim to remove
most of the pyritic sulfur and varying amounts of organic
sulfur.  Also, the first two processes are unique in that
the coal is chemically pretreated, then sulfur separation is
subsequently achieved by mechanical or magnetic means.  The
remaining nine processes are more typical in that sulfur
compounds in the coal are chemically attacked and converted.
A capsule summary of each major process follows.
MAGNEX PROCESS
     Pulverized  (minus 14 mesh) coal is pretreated with iron
pentacarbonyl, in this process to render the mineral components
of- the coal magnetic.  Separation of coal from pyrite and
other mineral elements is then accomplished magnetically.   The
process has been proven  on a  two hundred pound/day pilot plant
scale using the  carbonyl on a once-through basis.  The cost
of the Magnex process critically depends on  the  recycle of
iron  carbonyl.   It  is claimed that  iron carbonyl can be
produced  on-site  from carbon  monoxide  released  in the process.
However,  the continuous  recycle of  carbon monoxide to produce
low cost  iron carbonyl requires demonstration.   The use of
iron  carbonyl presents some difficulties  from a health and
safety standpoint.   Approximately  40  coals,  mostly of Appalachian
origin, have  been evaluated on  a  laboratory  scale.  For
the most  part,  the process will produce  coals which meet
                                 938

-------
TABLE i.  suwnr OF mxR OBWCAL OWL CLEWING PROCESSES
PROCESS &
SPONSOR
"ERDA" (PERC)
BRUCETON, PA.
"GE* GENERAL
ELECTRIC CO.,
VALLEY FORGE,
PA.
2 "SATTELLE*
* LABORATORIES
coumjs, OHIO
"JPL* JET
PROPULSION
LABORATORY
PASADENA/ CAL.
*IGT* INSTITUTE
OF GAS
TECHNOLOGY
CHICAGO, ILL.
METHOD
AIR OXIDATION &
WTER LEACHING 8
HIGH TEMPERATURE
AND PRESSURE
MICROWAVE TREATMENT
OF COAL PERMEATED
WITH HAOH SOLUTION
CONVERTS SULFUR
FORMS TO SOLUBLE
SULFIDES
MIXED ALKALI
LEACHING
CHLORINOLYSIS IN
ORGANIC SOLVENT
OXIDATIVE PRETREAT-
MENT FOLLOHED BY
HYDRpDESULFURIZATION
TYPE SULFUR
REMOVED
'X9BZ PYRITIC;
UPTOtjQZ
ORGANIC
^755 TOTAL S
MEE PYRITIC;
^25-5QZ ORGANIC
•^SKfYRITIC; UP
TO 701 ORGANIC
''SSLPYRITIC; UP
TO 8St ORGANIC
STAGE OF
DEVELOPMENT
BENCH SCALE H KG/
DAY (25 LB/DAY)
CONTINUOUS UNIT
UNDER CONSTRUCTION
BENCH SCALE
9KG/HR (20 LB/
HR) MINI PILOT
PLANT AND BENCH
SCALE
LAB SCALE BUT
PROCEEDING TO
BENCH AND MINI
PILOT PLANT
LAB AND BENCH
PROBLEMS
GYPSUM SLUDGE DISPOSAL
ACID CORRROSION AT
HIGH TEMPERATURES
PROCESS CONDITIONS
NOT ESTABLISHED
CAUSTIC REGENERATION
PROCESS NOT
ESTABLISHED.
CLOSED LOOP REGENERA-
TION PROCESS UNPROVEN.
RESIDUAL SODIUM IN
COAL
ENVIRONMENTAL
PROBLEMS. CONVER-
SION OF HCL TO 0_2
NOT ESTABLISHED
LOHBTU YIELD (<55Z).
CHANGE OF COAL MATRIX
ANNUAL OPERATING
COST $/TON CLEAN
COAL INCLUDING
COST OF COAL
51.6
41.8
55.9
46.0
55.3
  *RAW COAL COST IS INCLUDED AT $25/TON.

-------
TABLE 1.  SUTORY OF MftJOR OB1ICAL COAL CLEftNING PROCESSES
PROCESS 8
SPONSOR
HAZEN RESEARCH
INC.; GOLDEN
pbLORADO
£ v "SYRACUSE" -
SYRACUSE
RESEARCH CORP.,
SYRACUSE, N.Y.
v_
1-\ ."MEYERS", TRW,
' " INC. REDONDO
BEACH, CAL.
VJSB^
^Wil^^'i
METHOD
DRY PULVERIZED COAL
TREATED WITH FE
(C0)5 CAUSES PYRITE
TO BECOME MAGNETIC.
MAGNETIC MATERIALS
REMOVED MAGNETICALLY
COAL IS COMMINUTED
BY EXPOSURE TO N^
VAPOR; CONVENTIONAL
PHYSICAL CLEANING
SEPARATES COAL/ASH
OXIDATIVE LEACHING
USING FE2(S04;3 +
OXYGEN IN WATER
OXIDATIVE LEACHING
USING 02 AND HATER
- 8 MODERATE TEMP.
AND PRESSURE
TYPE SULFUR
REMOVED
UPt69(K
PYRITIC
PYRITIC
90-96%
PYRITIC
\
PYRITIC
STAGE OF
DEVELOPMENT

BENCH ft 91 K6/HR
(200LB/HR) PILOT
PLANT OPERATED
BENCH SCALE
8 METRIC TON/DAY
PDU FOR REACTION
SYSTEM. LABOR
BENCH SCALE FOR
OTHER PROCESS
STEPS.
BENCH SCALE
PROBLEMS

DISPOSAL OF S-CONTAIN-
ING SOLID RESIDUES.
CONTINUOUS RECYCLE OF
CO TO PRODUCE FE
(C0)5 REQUIRES
DEMDNSTRATiON
DISPOSAL OF SULFUR
CONTAINING
RESIDUES.
DISPOSAL OF ACIDIC
FESO4& CASO^o SULFUR
EXTRACTION STEP
REQUIRES DEMONSTRAT
TION
DISPOSAL OF GYPSUM
SLUDGE, ACID
CORROSION OF
--mcnK^ --:••; --: ;
ANNUAL OPERATING
COST */TON CLEAN
COAL INCLUDING
CO

•
.;
,
i
!
- 1
'.
^^AJSKl^ ^ , -__ ' \ „ ^ *RAW COAL COST 1$ INCLUDED AT IS/TON. > ^Y:/- . V v'i V'"^'W- "• ; ^C?"
fcl W OML


37.0
i - "• - -" . :
i . .
•-1- . • ' • .• '-
**^K-
|;^«?

-------
State regulations for sulfur dioxide emissions of 4.3 kg
S02/106 kg cal (2.4 Ib S02/106 BTU).
SYRACUSE PROCESS
     Coal of about 3.8 cm (IV) top size is chemically
comminuted by exposure to moist ammonia vapor at intermediate
pressure.  After removing the ammonia, conventional physical
coal cleaning then effects a separation of coal from pyrite
and ash.  Generally, 50-70% of pyritic sulfur can be removed
from Appalachian and Eastern Interior coals, producing coals
which meet State regulation for sulfur dioxide emission.
Construction of a 36 metric ton (40 tons per day) pilot plant
is contemplated.  No major technical problems are foreseen
for this process other than potential problems involving
scale-up to pilot plant size.
MEYERS PROCESS
     The Meyers' Process, developed at TRW, is a chemical
leaching process using ferric  sulfate and  sulfuric acid solution
to remove pyritic sulfur from  crushed coal.  The leaching takes
place at temperatures ranging  from  50° to  130°C  (120°-270°F);
pressures from 1 to 10 atmospheres  (15-150 psia) with a
residence time of 1 to 16 hours.  The final separation stages
use an organic solvent for removal  of elemental  sulfur from
the filtered clean coal.
                                 941

-------
     The TRW Process is the only chemical coal cleaning



process developed to the eight ton per day pilot scale level.



The current mode of operation is a pilot scale Reactor Test



Unit (RTU).  Only one part of the overall system, namely the



leaching-regeneration operation, has received intensive



laboratory study and this is also the only process component



incorporated in the RTU.  The RTU came onstream in late 1977



after encountering and solving many mechanical shakedown



problems.  Chemical reaction data for a few 24 hour runs using



minus 14 mesh coal indicate faster pyrite removal than with



the bench scale reactors.  Thirty-two different coals have



been tested on a bench scale:  twenty-three from the Appalachian



Basin;  six from the Interior Basin; one from Western Interior



Basin and two western coals.  The Meyers' Process is more



applicable to coals rich in pyritic sulfur, thus it is



estimated about one-third of Appalachian coal could be treated



to sulfur contents of 0.6 to 0.9 percent to meet the sulfur



dioxide emission requirements of current EPA NSPS.  Process



by-products are elemental sulfur, gypsum from waste water



treatment, and a mixture of ferric and ferrous sulfate, with



the latter presenting a disposal problem.




LEDGEMONT PROCESS




     The Ledgemont oxygen leaching process is based on the



aqueous oxidation of pyritic sulfur in coal at moderately high



temperatures and pressures.  The process has been shown to
                              942

-------
remove more than 90% of the pyritic sulfur in coals of widely



differing ranks, including lignite, bituminous coals, and



anthracite, in bench-scale tests.  However, little, if any,



organic sulfur is removed by the process.  The process became



inactive in 1975 during divestiture of Peabody Coal Company



by Kennecott Copper Co.  Although not as well developed as the



Meyers' Process, the Ledgemont Process is judged to be competi-



tive in cost and sulfur removal effectiveness.  The principal



engineering problem in this process is the presence of corrosive



dilute sulfuric acid, which may pose difficulties in construction



material selection and in choosing means for pressure letdown.



The process also has a potential environmental problem associated



with the disposal of lime-gypsum-ferric hydroxide sludge which



may contain leachable heavy metals.




ERDA (PERC) PROCESS




     The ERDA air and steam leaching process is similar to the



Ledgemont oxygen/water process except that the process employs



higher temperature and pressure to effect the removal of organic



sulfur and uses air instead of oxygen.  This process can remove



more than 90% of the pyritic sulfur and up to 40% of the organic



sulfur.  The process uses minus 200 mesh coal.  Coals tested



on a laboratory scale include Appalachian, Eastern Interior and



Western.  The developer's claim is that using this process,



an estimated 45 percent of the mines in the Eastern United States



could produce environmentally acceptable boiler fuel in accord-



ance with current EPA new source standards.  Effort to date
                               943

-------
 is on a bench scale,  but a mini-pilot plant is expected to
 start up soon.   The problems associated with this process are
 engineering in nature.   The major one is associated with the
 selection of materials  for the  unit construction.  Severe
 corrosion problems  can  be expected in this  process as the
 process generates dilute sulfuric acid which is highly corrosive
 at the operating temperatures and pressures.
 G.E.  PROCESS
      Ground coal (40  to 100 mesh)  is  wetted with sodium hydroxide
 solution and subjected  to brief (^30  sec.)  irradiation with
 microwave energy in an  inert atmosphere.  After two such treat-
 ments,  as much  as 75-90% of the total sulfur is converted to
 sodium sulfide  or polysulfide,  which  can  be removed by washing.
 No significant  coal degradation occurs.   That portion of the
 process  which recovers  the sulfur  values  and regenerates the
 NaOH  is  conceptual.   Work to date  is  in  100 gram quantities,
 but scale-up to  1 kg  quantities is  presently  in progress.  The
 process  attacks  both  pyritic and organic  sulfur,  possibly at
 about  the  same rate.  Appalachian  and Eastern Interior coals
 having wide  ranges  of organic and  pyritic sulfur contents have
 been tested with about equivalent  success.
 BATTELLE PROCESS
     In this process, 70 percent minus 200  mesh  coal  is  treated
with aqueous sodium and calcium hydroxides  at elevated  tempera-
tures and pressures, which removes nearly all pyritic  sulfur
                               944

-------
 and  25-50% of the organic sulfur.  Test work on a bench and
 pre-pilot scale on Appalachian and Eastern Interior coals has
 resulted in products which meet current EPA NSPS for sulfur
 dioxide emissions.  The conceptualized process, using lime-
 carbon dioxide regeneration of the spent leachant, removes
 sulfur as hydrogen sulfides which is converted to elemental
 sulfur using a Stretford process.  In addition to being a
 costly process, there are two major technical problems:
     •  The feasibility of the closed-loop caustic regeneration
        feature in a continuous process is as yet undemonstrated;
        and
     •  The products may contain excessive sodium residues,
        causing low melting slags and making the coal unusable
        in conventional dry-bottom furnaces.
 JPL PROCESS
     This process uses chlorine gas as an oxidizing agent in a
 solution containing trichlorethane to convert both pyritic and
organic forms of sulfur in coal to sulfuric acid.  Since removal
of sulfur can approach the 75% level, without significant loss
of coal or energy content, products should generally meet
current EPA NSPS for sulfur dioxide emissions.  To date the
process has been tested on a laboratory scale only, on several
Eastern Interior coals.  However, the effort will progress to
bench-scale and pre-pilot plant scale in the near future.  The
project is currently supported by the Bureau of Mines.  There are
some potential environmental problems with the process.  The
                                945

-------
trichloroethane solvent is listed by EPA as a priority pollutant
in terms of environmental effects.  A major cost factor is in
the need to recycle by-product hydrochloric acid for conversion
to chlorine.  At a chlorine consumption rate of 250 kg per
metric ton of coal, the incorporation of a Kel-Chlor or
similar unit in the JPL system will add approximately $10/metric
ton of coal.
IGT PROCESS
     This process uses atmospheric pressure and high temperatures
to accomplish desulfurization of coal.  These high temperatures
[about 400°C (750°F) for pretreatment and 815°C (1,500°F)
for hydrodesulfurization] cause considerable coal loss due to
oxidation, hydrocarbon volatilization and coal gasification,
with subsequent loss of heating value.  Experimental results
have indicated an average energy recovery potential of 60%
for this process.  The treated product is essentially a carbon
char with 80-90% of the total sulfur removed.  Most of the
experimental work to date has been accomplished with four
selected bituminous coals with a size of plus 40 mesh.  Present
effort is on a bench-scale level.  The net energy recovery
potential of the system and the change in the coal matrix
by the process have been identified as possible severe problems
for the IGT Process.  The process must be developed to a
stage where the process off-gas can be satisfactorily utilized
for its energy and hydrogen content.  If this cannot be
                                946

-------
technically and economically accomplished, the process will



prove to be inefficient and too costly for commercialization.




KVB PROCESS




     This process is based upon selective oxidation of the



sulfur constituents of the coal.  Dry coarsely ground coal



(plus 20 mesh) is heated in the presence of nitrogen oxide



gases for the removal of a portion of the coal sulfur as



gaseous sulfur dioxide.  The remaining reacted, non-gaseous



sulfur compounds in coal are removed by water or caustic washing.



The process has progressed through laboratory scale, but is



currently inactive due to lack of support.  Laboratory experi-



ments with five different bituminous coals indicate that the



process has desulfurization potential of  up to 63 percent of



sulfur with basic dry oxidation and water washing treatment



and up to 89 percent with dry oxidation followed by caustic



and water washing.  The washing steps also reduce the  ash



content of the coal.




     In cases where dry oxidation alone could remove  sufficient



sulfur to meet the sulfur dioxide emission standards,  this



technology may provide a very  simple  and  inexpensive  system.



Potential problem areas for this system are:




     •  oxygen concentration requirements in  the treat gas



        exceed the explosion limits  for  coal  dust,  and thus



        the operation  of this  process may be  hazardous.
                                947

-------
     •  Nitrogen uptake by the coal structure will increase
        NO  emission from combustion of the clean coal product.
          J^
ARCO PROCESS
     Little information is available on this process.  It is
presently in the pre-pilot plant stage of development and is
alleged to remove both pyritic and organic sulfur.  The process
was wholly funded internally until recently, when EPRI financed
a study on six coals in which there was a wide distribution of
pyrite particle size.  Energy yield for the process is alleged
to be 90-95%, and ash content can be reduced by as much as 50%.

3.0  PROCESS PERFORMANCE COMPARISONS OF SULFUR REMOVAL, HEATING
     VALUE RECOVERY AND COST
     A comparison of process performance and costs can best be
accomplished by looking at each process on a common coal feed
basis.  This basis allows the comparison of the following
parameters process by process:
     •  Weight yield of clean coal product based upon a feed
        coal rate (moisture free basis) of 7,110 metric tons
        (7,840 tons) per day  [7,200 metric tons (8,000 tons)
        per day of 2 percent moisture coal];
     •  Weight percent sulfur in the clean coal product based
        upon the sulfur removal efficiency of the process;
     •  Heating value yield of the process based upon a feed
                              948

-------
        coal value of 6,800  kg cal/kg (12,300  BTU/lb);  and
     •  Costs -
        total capital costs  for the process
        total annual processing costs,
        annual costs per metric ton of clean coal,  including
        coal costs and excluding coal costs, and
        annual costs per heating value unit, including
        coal costs and excluding coal costs.
This comparison data is shown in Tables 2 and 3, arranged
according to categories of processes.
     The common coal feed selected is a bituminous coal from
the Pittsburgh seam, which cannot readily be cleaned by
conventional physical washing techniques to meet the current
new source performance standards for sulfur dioxide emission. .
However, this coal does have an organic sulfur content low
enough  (0.7 weight percent)  so that complete removal of pyritic
sulfur would result in a product which will meet current NSPS
for sulfur dioxide emission.
     The percent  removal of pyritic and organic sulfur assigned
to each process is based on data supplied  by individual develop-
ers.  The tables  indicate a range of S02 emission  levels  for
the clean coal products of 1.5 to  3.8 kg/106 kg cal  (0.8  to
2.1 lb/106 BTU).   The  calculated sulfur  levels  for processes
which remove both types of sulfur  are lower than the  2.2  kg/106
                                 949

-------
                       TABLE 2.   Performance and Cost  Comparison  for Major  Chemical
                                  Coal Cleaning Processes Which  Remove Pyritic Sulfur  Only.

Net coal yield, tons/day*
Vfeight % sulfur in the product
Heating value, (BTU/lb)
(Ib SO2/*M BTU)
Percent net BTU yield
Costs
Capital ($M1)
Annual processing ($i"M)
$/annual ton. of clean
coal, excluding coal cost
$/annual ton of clean
coal, including coal cost
§/*W BTU , excluding
coal cost
$/MM BTU ,Aincluding
coal cost
Feed*
7,840
1.93
12,300
3.1
—

—
—

—

—

—
—
TOT
7,056
0.83
12,835
1.3
94

109
37.2

15.6

43.4

0.61
1.69
IOL
7,056
0.83
12,835
1.3
94

114.0
45.3

19.1

46.9

0.74
1.82
Magnex
6,225
0.97
12,400
1.6
80

37.8
19.2

9.2

40.7

0.37
1.64
Syracuse plus
physical
cleaning
6,225
1.50
14,600
2.1
95

49.0
12.2

5.8

37.0

0.20
1.27
VO
Ln
O
|A11 values reported are on a moisture free basis.
 The coal selected is a Pittsburgh seam coal from Pennsylvania which contains 1.22 weight percent pyritic,
                                    * ""1                      that this o«l has a heatd^ val«
     Assumes coal feed @ $25/ton.
"""1C
                                                          «

-------
                             Table  3.   Performance and Cost  Comparison for Major Chemical
                                        Coal  Cleaning  Processes Which  Remove Pyritic and
                                        Organic Sulfur.

Net coal yield, tons/day*
Weight % sulfur in the product
Heating value, BTO/lb
Ib SQi/VM. BTU
Percent net BTU yield
Costs
Capital ($Mfl
Annual processing ($M4)
$/annual ton of clean
coal, excluding coal cost
$/annual ton of clean coal,
including coal coet^
$/HM BTU, excluding
coal cost
$/tei BTU, including
coal costA
Feedt
7,840
1.93
12,300
3.1
—

—
—

__
—
—
EREft
7,056
0.65
12,835
0.9
94

166.8
56.6
23.8
51.6
0.92
2.00
GE
7,526
0.50
12,300
0.8
96

102.0
39.8
15.7
41.8
0.64
1.69
Battelle
7,448
0.65
11,350
1.2
88

168.6
74.2
29.6
55.9
1.30
2.45
JPL
7,135
0.6
12,300
1.0
91

103.2
44.4
18.5
46.0
0.75
1.86
IGT
4,704
0.55
11,685
0.9
57

134.6
38.3
24.2
65.8
1.03
2.81
KVB
6,690
0.61
13,120
0.9
91

65.9
41.0
18.2
47.5
0.69
1.81
AFCO
7,056
0.69
12,400
1.1
91

—
58.7
25
	
—
—
vo
Ul.
         All values reported are on a moisture free basis.
         The coal selected is a Pittsburgh seam coal from Pennsylvania which contains 1.22 weight percent pyritic,
           0.01 percent sulfate and 0.70 percent organic sulfur.  It is assured that this coal has a heating value
           of 6,800 kgcal/kg (12,300 BTU/lb).
         Assures coal feed § $25/ton.

-------
kg cal (1.2 lb/106 BTU) current NSPS for sulfur dioxide emission,
Of the four processes which remove pyritic sulfur only, two
(TRW and Ledgemont) will produce slightly higher sulfur levels
than that required to meet the current NSPS; however, within
the levels of accuracies involved they also might be considered
to be in compliance.  The remaining two processes [Magnex^ and
Syracuse] would produce coal which would be in compliance only
with a standard of 4.3 kg/106 kg cal (2.4 lb/106 BTU) for
sulfur dioxide emission.
     The heating value yields estimated for these processes
are generally greater than 90 percent, with a range from a low
57 percent for the IGT Process to a high of 96 percent for the
GE Process.  All heating value yields reflect both the coal
loss due to processing and the coal used to provide in-process
heating needs.  However, with the exception of the IGT Process,
the actual coal loss due to processing is claimed to be small.
For most processes, the major heating value loss is due to the
use of clean coal for in-process heating.
     It is believed that the high yield estimated for the GE
Process may not adequately reflect the heat requirements that
may be needed to regenerate the caustic reagent used in
the process.  This process is in its early stage of development
and as such, the energy requirements for the process cannot
be properly assessed at this time.  It is possible, that in
the final analysis, the heating value recovery from this
process will be more in line with other chemical coal cleaning
processes.

                               952

-------
COST COMPARISON
     Estimates of capital and annual operating costs for each
major chemical coal cleaning process are presented in Tables
2 and 3.  These estimates are based on an assumed plant through-
put capacity of 7,200 metric tons (8,000 tons) per day,
equivalent to a 750 M.W. utility boiler.  The total annual
operating costs for each process, including and excluding
cost of the raw coal, have been expressed also in terms of
dollars per ton and dollars per million BTU heat content in
the coal.
     The capital cost estimate prepared by each process develop-
er was used as the basis of the cost estimates in this report.
In some cases, these costs were modified to allow the evaluation
of the various processes on a comparable basis.  The estimate
capital costs assume a grass roots operation  including costs
for coal crushing, grinding, product compacting and feed and
product handling.  The capital costs also include land acquisi-
tion and site development, off-site facilities, and engineering
and design costs.  A contingency allowance of 20 percent has
been included in all estimates, with the exception of TRW's.
A lower contingency allowance  (10 percent) was used for the
TRW process since it is at a more advanced stage of develop-
ment and adequate process data is available to develop the
economics of this process with a greater degree of confidence.
                                953

-------
      Annual operating costs are based on a 24-hour workday,



 90.4  percent service factor (330 days per year)  basis.   The



 capital cost is amortized over a period of 20 years at  10



 percent interest per year.  Where adequate information  was



 available,  the utilities and chemical consumptions are  based



 upon  actual process  demand.   The operating labor costs  reflect



 wage  rates  for the Pittsburgh,  Pennsylvania,  area.   The



 estimates for the maintenance  and supplies, general and



 administrative,  taxes and insurance  are  taken as 5,  1.5,  2



 and 1 percent on total installed plant capital cost (TPC),



 respectively.




 CAPITAL COST COMPARISONS




      In general,  pyritic sulfur  removal  processes  require  the



 least amount of  capital  investment.   However,  these  processes



 have  limited sulfur  removal  efficiencies.




      Among  processes  that  remove  both organic  and pyritic



 sulfur,  the  KVB  Process  appears  to have  the lowest  capital



 investment,  since it  is  a  partially dry  process  requiring  lower



 investment  for the dry reaction  section.  The  high capital



 cost  of  the  Battelle  Process is due to the processing steps



 associated with reagent  regeneration.




      The high capital cost of the ERDA Process is due to



costly equipment associated with the handling of dilute sulfuric
                              954

-------
acid at elevated temperatures and pressures.  At the process



operating conditions the dilute acid is highly corrosive and



it poses problems in terms of selection of construction



material for equipment and devices which are exposed to the



corrosive atmosphere.




     Very little is known about the ARCO Process details and



process chemistry.  Therefore, a capital cost estimate was



not developed for that process.




OPERATING COST COMPARISONS




     The ranges of annual operating costs, including raw coal



cost, in terms of $/ton and $/106 BTU are $37.00 to $65.00 and



$1.27 to $2.81, respectively.  Pyritic sulfur removal processes



using chemical pretreatment are the least expensive of all



processes studied.  Operating cost for the Magnex process



depends primarily on the cost of iron pentacarbonyl manufacturing,



In the estimate presented in Table 2, an operating cost of



$0.22/kg for the iron carbonyl manufacturing was used, as



projected by the developer.  At a consumption rate of 10 kg/



metric ton of coal, each $0.20 cost increase per kilogram of



iron carbonyl manufactured would increase the annual operating



cost of this process by about 27 percent.




     Between the two processes which remove pyritic sulfur by



leaching, the TRW Process appears to be slightly less costly.



In the Ledgemont Process the fixed charges associated with the
                               955

-------
 higher  capital  investment  have  an  adverse  impact  on  the  annual
 operating costs.   Additionally,  the TRW Process has  a
 higher  probability of  technical  success, since  it  is  currently
 active  at a  PDU stage.   The  Ledgemont  Process, tested  only
 at  a mini-pilot plant  level,  is  currently  inactive.
     The  most expensive  processes,  in  terms of energy  output,
 are the IGT  process followed closely by the Battelle Process.
 Laboratory data available  at  this  time,  indicate  a very  low
 BTU recovery for the IGT Process.   The Battelle Process  is
 adversely impacted by  the  fixed  charges  associated with  the
 high capital investment  and by the  costs associated  with
 chemicals consumption  and  reagent  regeneration operations.
     The  least  expensive process capable of removing pyritic
 and organic  sulfur is  the  GE  Process followed closely  by the
 JPL and KVB  Processes.   The GE estimate  is based, however, on
 early laboratory data  and  it  is  quite  possible that  the  project-
 ed costs  will prove somewhat  inaccurate  in the long  run.  The
 basic process utilizes a caustic reagent in coal  pretreatment
 and the costs associated with caustic  consumption and  caustic
 regeneration are questionable at this  time.  The  JPL Process
estimates  are also  preliminary since investigations  on this
process are at  an early  stage.  The  annual costs  reported for
the KVB Process are also preliminary since the process is at
its early stages of development and  accurate conceptualization
                               956

-------
of the process for purposes of economic evaluation is difficult.



The main advantage of the KVB Process is the simplicity of



the first stage dry oxidation process.  If the dry oxidation



process can be successfully demonstrated using coarse coals,



this process would be an inexpensive technology for beneficiation



of coals where partial removal of sulfur would substantially



upgrade the coal.




     Among the processes capable of removing pyritic and organic



sulfur the ERDA Process has one of the highest probabilities



of technical success.  The process is currently active and



most technologies employed in this system have been  already



tested in other systems such as Ledgemont and TRW.   The process



is attractive because it is claimed to remove both types of



sulfur and uses air  as a major reagent.  Furthermore,  the



sulfur by-product from this process is a dilute sulfuric acid,



rather than iron sulfate, which greatly simplifies the coal



washing operations.  The process  is somewhat expensive due



to high operating temperature  and pressure  requirements  and



the  corrosive nature of  dilute acid present in  this  system.



The  dilute sulfuric  acid at  the operating conditions of  the



ERDA Process will require  the  use of  expensive  construction



material  and  consequently  a  higher capital  investment cost.




      Table  4  presents  a  cost effectiveness  summary derived from



 information presented  in Tables  2 and 3.   Costs are  presented



 in terms  of dollars  per  percent  of sulfur removed from coal
                                957

-------
                         3AOE 4.  COST H-VHUTIVENESS COMPARISON OF CHEMICAL COM. CLEANING PROCESSES*
Process
fife
Magnex ^?
Syracuse S
Kiysical
flmnina

TRW
LCL
HOA
GB
Battelle
JPL
XGT
KVB
AHOD
Type of
Sulfur
Removed
P*
P
P
P
(PSD)*
(P»)
(PCO)
(PSO)
(PSO)
(PSD)
(PSO)
Sulfur
Raooved
(Wt.%)*
0.96
0.43 P
1.10
1.10
1.28
1.43
1.28
1.33
1.38
1.25
1.24
Process
COSt <$/
metric ten
incl. cost
of coal)
44.8
40.8
47.9
51.6
56.9
46.0
61.6
50.7
72.6
52.4
Jl
Cost Effect-
iveness of
5 removal,
$/% S removed
46.6
94.9
43.5
46.9
44.5
32.2
48.1
38.1
52.6
41.9
_A
Cost
Effect-
iveness
Rarfe-
ing
2
4
1
3
4
1
5
2
6
3
-
Meets
EPA
NSPS*
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Probability
of Success
(based on
available
info.)
85%
70%
90%
50%3
70%
60%
35%
55%
20%3
20%'
_A
Time Frame
for OonrotfrcJL'"
al Avail-
ability
(Years) «
2-3
2-3
<3
4-5
5
5
4-5
5
5
5
_A
in
00
             MOOES:    *  Based on Pittsburgh seam coal from Pennsylvania ^hich contains 1.22 weicfrit percent pyritic,
                       .        0.01 percent sulfate and 0.70 percent organic sulfur.
                       . P = pyritic sulfur.
                       ^ (PSO) = pyritic and organic sulfur.
                       . Tine frame assunes  continuing effort or renewed effort starting immediately.
                       " Infoniaticn available is insufficient to mate educated guesses.
                         Process not currently active, partially accounting for low probability of success.
                       £80 percent, yield of product assumed in cleaning plant.

-------
regardless of the quality of the treated product.  The processes
are then rated based upon the cost effectiveness of sulfur
removal.  The subjective probability of success assigned to
each process is based on integration of several factors such
as:
     •  available experimental data;
     •  our understanding of the status of the process;
     •  known product quality deficiencies;
     •  known process problems; and
     •  the degree and quality of effort assigned to the
        individual program.
     In conclusion, all chemical coal cleaning processes
discussed in this section offer a possibility of converting
coal into clean fuel.  Each process has an area of application.
However, processes that remove both pyritic and organic
sulfur are judged to have a greater impact in future coal
utilization.
                               959

-------
               STATUS OF THE REACTOR TEST PROJECT FOR CHEMICAL
                    REMOVAL OF PYRITIC SULFUR FROM COAL

                       M. J. Santy and L. J. Van Nice
                                  TRW, Inc.
                         Redondo Beach, California
                                  ABSTRACT
     Plant checkout and shakedown was completed at the end of September and
initial plant process performance was evaluated on an Appalachian coal.
Operation of the plant through January of 1978 demonstrated that the Reactor
Test Unit (RTU) could be run continuously in three-shift operation to reduce
the coal from 2.4 Ibs S02/106 Btu to a level of 1.0 to 1.2 Ibs S02/106 Btu,
after rinsing and extraction of generated elemental sulfur.  There was no
measurable coal oxidation during processing and leach rates in the plant were
greatly improved over bench-scale values.  The leach solution/coal/oxygen
environment was found to be corrosive to the installed stainless steel
reactor, necessitating future upgrading to support additional cesting.  Bench-
scale experimentation showed that the leach solution can be used as a homo-
geneous dense-media tp efficiently gravity-separate coal prior to processing.
Beneficial engineering cost improvements are obtained based on using this
approach, resulting in capital cost estimates of $68-$69/KW and with $0.44-
$0.50/106 Btu processing costs, including amortization of capital, for input
coal costing $0.78-$0.81/106 Btu.   Overall energy efficiency was 93 to 96
percent.
                                      960

-------
INTRODUCTION
     The Meyers Process 1s a technology for chemically removing essentially
all of the pyrltlc sulfur from coal through a mild oxldatlve treatment.
Important pollutant trace elements, lead, cadmium and arsenic, are removed
at the same time.  It can be used to provide compliance coal for Industrial
boilers and smaller electric utilities, and for recovery and desulfurlzlng
waste fine coal rejected from mining and washing operations.  The develop-
ment of the process 1s sponsored by the U.S. Government's Environmental
Control Technology Program administered by the Environmental Protection
Agency.

     A process schematic 1s shown 1n Figure 1.  Coal 1s mixed with an aqueous
solution of ferric sulfate (Step 1), previously derived from the coal, to
form a slurry.  The slurry 1s raised 1n temperature to 100-130eC (Step 2)
where the ferric sulfate oxidizes the pyrltlc sulfur content of the coal to
form elemental sulfur and additional Iron sulfate.  At the  same time oxygen
or air Is Introduced to the wet slurry mix to regenerate the reacted ferric
                                      961

-------
          H2S04
NO
Ov
10
    vJQAL
(F. S2 + F*2 (S04)


H*°4+°2lS
                                   F. S0
                                   GnO-
                                                    FILTER
                                                   1
                                                NEUTRAlH
                                                 IZATION
                                                                                                          COAL
                                            Figure 1.  Meyers Process

-------
sulfate.  Iron sulfate dissolves into the leach solution while the elemental
sulfur is solvent-removed in a second extraction (Step 3).  The coal is
dried and solvent recovered (Step 4).  The products of the process are iron
sulfate, which may be limed to give a dry gypsum and iron oxide material,
and elemental sulfur.  Trace elements from the coal are bound in with the
stabilized gypsum/iron oxide solid.

     Elemental sulfur is the most desirable product which car, be obtained
in the process of controlling sulfur oxide pollution, and be easily stored
without secondary pollution or may be marketed.  The gypsum/iron oxide is
a safe and storable solid.

     Very recent operating experience has demonstrated that the iron sulfate/
sulfuric acid leach solution can be used as a homogeneous dense media to
efficiently gravity-separate fine coal  at specific gravities of 1.2-1.35.
Beneficial engineering cost improvements are obtained using this gravity-
separation technology.  A significant portion of the input coal, which char-
acteristically floats in the leach solution and is almost pyrite free, may
bypass the reactor, elemental  sulfur extraction and dryer portions of the
Meyers Process (Figure 2).  This revised technology is termed the Gravichem
Process.   For example, when applied at bench-scale to a Tennessee Valley
Authority (Interior Basin) coal  containing 12% ash and 7 Ib SOj/lO6 Btu,
two products are obtained in roughly equal amounts, a 4% ash float coal
containing 3 Ib S02/106 Btu, and an 11-12% ash sink coal  containing 4 Ib
S02/10  Btu after treatment by the Meyers Process.   Both of these products
meet state SOX emission standards for utility systems using this coal.
Because of these promising results, TVA has shipped 300 tons of coal  to TRW

                                     963

-------
           F.2(S04)3
 GRAVITY
SEPARATOR
   (FeS2)
                   FILTER
                  WASH
FILTER
G
                     REACTOR
            I   MEYERS PROCESS
            L.     	
                                                   SULFUR
                  		J
                     Figure 2.   Gravichem  Process

-------
for future processing and evaluation.   A description  of the  test plant,
operational results and process sulfur emissions  reduction  potential  is
presented in the sections to follow.

THE TEST PLANT
     After testing the process at bench-scale on  some 40 U.S.  coals  (Meyers,
1977; Hamersma and Kraft, 1975; Hamersma, et al., 1973) and  performing  200
fully material-balanced bench-scale extractions  (Hamersma,  et  al.,  1973;
Koutsoukos et al., 1976), the value of the process for controlling  the
sulfur content of coal was firmly established.  Additionally,  the data
necessary for the design of a test plant was then available.  Engineering
design criteria obtained through extensive studies at TRW (Hamersma et  al.,
1973; Koutsoukos et al., 1976; Van Nice and Santy, 1977) and various other
engineering organizations (Nekervis and Hensley, 1975; McGee,  1975) provided
confidence that the process was economically attractive and identified
important engineering data which could only be obtained by operation of a
pilot-plant test facility.

      It was determined  that  the initial  test  facility  process evaluation
should concentrate on  the key  process steps of coal/Ieach solution slurry
formation,  leaching, regeneration and filtration.  A test plant, termed  the
Reactor Test  Unit  (RTU), was  constructed at TRW's San  Juan Capistrano site
for  the purpose of testing  these  portions of  the  process (Figure 3).  The
plant, sized  to process from 1/8  to 1/3  ton/hour  of  coal, was dedicated  in
April  1977.
                                       965

-------
Figure 3.  Reactor Test Unit

-------
     The facility was designed to demonstrate those unit operations  com-
prising the front end of the Meyers Process, namely, coal/reagent mixing,
primary pyrite reaction and reagent regeneration, secondary (finishing)
pyrite reaction and slurry filtration.   Designed for high flexibility,  the
RTU has the capability of processing a  range of suspendable coals up to
approximately 8 mesh top-size and coarse coals up to approximately 3/8-inch
top-size.  Spent reagent may be regenerated either exclusive of, or  simul-
taneously with, coal leaching.  The primary reactor may be used as either
a five-stage or a three-stage reaction  unit to increase the available range
of coal processing times.

     A process flow diagram of the RTU  is shown schematically in Figure  4.
Fine coal ground to the desired size is loaded in feed tank T-l.  Dry coal
is fed continuously by live bottom feeder A-2 to weigh belt A-3 which
discharges through rotary valve A-4 to  three-stage mixer T-2 (stream 1).
Aqueous Iron sulfate leach solution (stream 2) enters T-2 after preheating
1n heat exchanger E-2 and passing through foam scrubber T-3.  Steam is
added (stream 3) to raise the slurry to Its boiling point.  Foaming, which
may occur during the early stages of mixing, ceases when coal particle
wetting 1s complete.  The heated slurry (stream 4) is then pumped to five-
stage pressure vessel R-l 1n which most of the pyrite is removed.  R-l
slurry heating is achieved by direct Injection of steam into any or all
reaction stages.  Reagent regeneration  may be carried out simultaneously
with pyrite leaching by means of oxygen Injection into any or all reaction
stages (stream 5).  Unused oxygen saturated with steam (stream 6) 1s con-
tacted 1n foam knockout drum V-l with the feed reagent (stream 7) to pre-
heat the reagent and cool vent gases.  Slurry 1n any stage of R-l may be
                                     967

-------
11 COAL
W MECHANICAL
                                                       ATMOC.
                                                                        WATtt
                                                            TO TIUCK FO« mSPOSAL
  p-n
                 P-12
                                                   P-U
                       Figure  4.   RTU  schematic
                                          968

-------
cooled by means of cooling water heat exchanger E-l  which  may be applied
to slurry recirculation loops for removal  of excess  heat of reaction.   Vent
gas from both T-3 and V-l  are water scrubbed in T-4  to remove any traces
of acid mist.

     Reacted coal slurry (stream 8), at elevated temperature and pressure,
is flashed into flash drum T-5 for gas/liquid separation.   Generated steam
(stream 9) is condensed in T-4, and the condensate plus any entrained acid
mist is removed with scrubber water.  Reacted slurry (stream 10) is fed to
belt filter S-l.  The filtrate, which is regenerated leach solution, is
removed from the coal slurry through evacuated filtrate receiver V-2 and
pumped (stream 12) to leach solution storage tank T-7.  Coal on the filter
belt (Figure 5) is washed with water (stream 11) and discharged to coal
storage.  Wash water 1s removed through evacuated wash water receiver V-3
and pumped (stream 13) to liquid waste holding tank T-9 for subsequent
disposal.

     As a processing alternate, partially processed slurry from T-5 may be
loaded into  secondary reactor R-2  for final depyritlzation 1n a batch mode.
Slurry may be  retained, heated  and agitated for extended  periods of time
1n R-2 prior to being pumped  to S-l.

     Coarse  coal  contacting  vessel T-6  1s a steam heated  Insulated  tank in
which  hot reagent may flow through a bed of retained  coarse  coal.   This
unit  1s  used principally  to  convert regenerated leach  solution  1n  storage
tank T-7 or  T-8  to  a more depleted solution simulating recycle  reagent after
secondary reaction.  T-6  1s  basically  a coarse coal reactor  and,  1f
                                      969

-------
 appropriate sampling ports  and possibly some flow distribution  internals
 were added, could be used  to obtain design data for coarse coal  processing.

 PLANT OPERATION AND PROJECT RESULTS
      Plant checkout and  shakedown  was  completed at the  end of September
 1977 and initial  plant process performance was  evaluated  on coal  donated
 by the American Electric Power Service Corporation (AEP)  from its Martinka
 mine in West Virginia (Hart et a!.,  1978).   Operation of  the plant, through
 January of 1978,  demonstrated that the RTU could  be  run continuously in
 three-shift operation to reduce the  AEP coal  from 2.8 Ib  S02/10   Btu to a
 level  of 1.0-1.2  Ib S02/10   Btu, following rinsing and extraction of
 generated  elemental  sulfur  (Table  1).   Thus,  the  process  coal meets New
 Source Performance  Standards  of 1.2  Ib S02/10   Btu.  The  coal product is
 shown  as a  cake on  the plant  filter  belt in  Figure 5.  There was no measur-
 able coal oxidation;  in  fact,  heat content  increases averaged 350 Btu/lb
 due  to pyrite and ash  removal.   Leach  rates  in  the RTU were  greatly improved
 over bench-scale values, thus  enabling bypass of  the secondary reactor.
     To fully appreciate the apparent leach reaction rate increase, data
obtained from the RTU acidified Iron reagent operations is correlated with
the previously established (at bench-scale) pyrite leaching rate expression,
namely:
          -dW.
where
     r.     1s the pyrite leaching rate, expressed 1n weight of
           pyrite removed per 100 weights of coal per hour (rate
           of coal pyrite concentration reduction),
                                      970

-------

Run Reactor Temp.
°F
Starting Coal
1 222
2 232
3 234
Coal
Ash
% w/w
16.11
±0.261
12.97
±0.0894
12.02
±0.636
12.51
+0.953
Analysis
Heat Content,
Btu/lb
12508
± 77
13258
± 162
13388
+ 91
13265
+ 155
Sulfur lb S02
% w/w 1Q6 Btu
1.73 2.8
±0.045
0.68 1.03
±0.044
0.78 1.17
±0.065
0.75 1.13
±0.033
Table 1.  Test plant data  taken  over  5-day period

-------
          Figure 5.  Desulfurlzed coal on filter belt

W     1s the pyrite concentration in coal at time  t  1n
      wt. percent,
t     1s the reaction (leaching) time in hours,
KL    1s the pyrite leaching rate constant (a function of
      temperature and coal particle size) expressed in
      (hours)"  (wt. percent pyrite in coal)  ,
Y     is the ferric-Iron-to-total-iron ratio in the leacher
      at time  t, dimension!ess, and
                               972

-------
with
     KL = AL exp (-EL/RT)                                              (2)
where
     A,     is the Arrhenlus frequency factor in the units of K^,
     E,     is the apparent activation energy in calories /mole,
     R     is the gas constant in calories/mole °K, and
     T     is the absolute temperature, in °K.

     This rate expression was used in conjunction with a model of the
reaction system as a series of continuous-flow stirred-tank reactors.
Measured slurry temperatures and reagent Y values for each reaction stage
were input for each experimental condition and the value of K^ was deter-
mined at the  various reaction temperatures tested.
      Equation  (2)  indicates  that  a  plot of  In  1^ vs.  1/T  should yield a
 straight line  having  a  slope of -EL/R  and an intercept of In AL-  An
 Arrhenius plot of  the data  from several experiments  is presented  in Figure
 6.   A very good linear  correlation  was obtained.   The apparent  activation
 energy and frequency  factor Indicated  by  these data  are:
      EL = 26.9 x 103  calories/mole, and
      AL = 9.2  x 1014  Wp1  hr"1

      These values may be compared with bench-scale coal  processing  results
 which yielded an EL (bench) of 11.1 x 103 calories/mole  and AL  (bench)  of
 2.95 x 105 W"1 hr"1.   Hence, KL  (RTU) was measured to be 3 to 8 times
 greater  than K, (bench) for 14 mesh top-size coal  at temperatures between
                                      973

-------
    3.
   1.0


    .9
X
 .0. .8


 1 .7
    .6
§   .5
o
    .3
o
*f
                       270°F
                       250°F
230°F
      2.4
             2.5
                                     1/T, -
                                                          2.6 x 10
                Figure   6.  Arrhenius plot of data obtained

                             during  RTU processing
                                        974

-------
230°F and 270°F.   The deviations  of AL  and  EL  from the  values obtained
during batch reactor (bench scale)  operation were only  partially  antici-
pated.  The apparent value of AL  was expected  to increase during  stagewise
operation as the mixing in reaction stages  deviated from ideal  and the
average particle residence time per stage increased. Also, under non-ideal
mixing, pyrite rich particles might be expected to have longer  residence
times than pyrite lean particles  which have a  lower density. Thus, coal
processing in a continuous flow stirred tank reactor is expected  to result
in a higher apparent AL value than would identical coal processing in a
batch reactor.  However, the apparent doubling of the activation  energy EL
above E,  (bench) was not anticipated.  To effect such an increase in EL
requires  that deviations from ideal mixing or segregation of pyrite rich
coal  particles increase with increasing temperature.  A decrease  in reagent
density could increase coal segregation despite  mechanical mixing and,
perhaps,  selectively cause the pyrite  rich  coal  particles  to remain longer
1n  each reaction  stage.   While density changes  due  to  temperature alone are
small,  this  effect coupled with  reagent dilution (due  to  direct  steam  heat-
 ing in  the RTU)  can be significant.  The combined temperature  and steam
 dilution effects  are estimated to  have resulted in mean reagent  densities
 of 1.15 g/cc during 230°F tests, 1.08  g/cc during 250°F tests  and 1.06 g/cc
 during 270°F tests.  Thus, significant reagent density differences  occurred
 between the 230°F and 270°F experimentation which may  have resulted in the
 apparent increase in the pyrite  leaching activation energy. Whether or not
 this density difference 1s 1n Itself sufficient to cause the observed  factor
 of 2 Increase 1n activation energy cannot be determined from available data.
 However, 1f part of the observed Increase 1s the result of a density effect
                                       975

-------
then reagent density would become an Important reaction design parameter
for systems utilizing stirred tank reactors.  Changes 1n viscosity and
slurry concentration may also be important.

     As is the case with most new process pilot-plant-scale startups,
numerous equipment and materials problems were encountered during operation.
The more severe problems resulted in significant plant downtime.   These
problems included:  filter belt (S-l) misalignment and hangup, errors  in
weigh belt (A-3) calibration,, slurry feed pump (P-l)  malfunctions and
corrosion in primary reactor (R-1) and its associated pump-around loops.
All of these equipment problems were identified and solved during the
operational phase of the project.  It is important to note that,  in general,
none of the problem areas encountered during RTU operation were process
oriented but rather pilot-scale equipment related.

     During the first 2 months of operations, RTU vacuum filter belt (S-l)
experienced numerous shear pin failures.  These failures usually  occurred
several hours into experimental runs and resulted in  premature run termina-
tion.  The problem was originally believed to be one  of improper  belt
alignment resulting in excessive power train exertion.  However„  following
several belt alignments and power train adjustments„  which did not solve
the shear pin failure problem, it was further determined that excessive
frictional forces were being experienced at the rubber-drive-belt/vacuum-
pan interface.  These forces were sufficiently strong to result in one
instance of drive belt separation (Figure 7).  The problem was resolved by
attaching Teflon skids to the vacuum pans at the rybber belt interface.

                                    976

-------
\o
                                                                                   Rubber Belt
                                                                                   Drive
                                                                  Cloth Filter
                                                                  Belt Roller
                            Figure 7.  Ripped S-l filter belt (cloth belt removed)

-------
The  belt was repaired, reassembled and placed back Into service with no
further shear pin failures or belt tears experienced.

      During the Initial phases of shakedown operations, RTU weigh belt
coal  feeder (A-3) was found to be overly temperature sensitive and unable
to operate to the specified calibration limits.  Most of the belt internals,
including mechanical and electric components, were modified and/or replaced
by the manufacturer during several cycles of rework at both the Capistrano
Test  Site and the manufacturer's facility.  The modified unit which is
currently installed in the RTU has repeatedly demonstrated its ability to
achieve the desired accuracy range of ±1 percent over the approximate 100
to .1000 pound per hour delivery range.

     Another recurring problem experienced during RTU operations was that
of slurry feed pump (P-l) failure.  Feed pump (P-l) and its replacement
spare are six-stage progressive cavity type pumps.  The pump failures were
manifested as gradual losses of pumping capability at constant head pressures,
It was determined upon inspection of pump internals that the chrome plated
316 stainless steel rotors were experiencing rapid corrosion and/or erosion
(Figure 8).  Subsequent material  evaluations and discussions with the pump
supplier Indicated that the pumps were Inadvertently Incorrectly specified
and that the units should have been supplied with Hastelloy-C rotors.   Due
to the relatively long delivery time (several  months)  for obtaining re-
placement Hastelloy-C rotors,  efforts were made to resurface and rechrome
the existing rotors and to operate the RTU while awaiting delivery of the
      •
replacement rotors.  The reworked 316 stainless steel  rotors were found to
operate successfully for times ranging from 1/2 hour to 100 hours depending

                                     978

-------
Figure 8.  Corroded/eroded P-l rotor

-------
 on the run conditions and the degree of previous chrome plating required on
 the specific rotor.  Recently, the new Hastelloy-C rotor for P-l  was received
 and installed.

      The last of the major problems encountered during RTU operation was
 that of reactor section corrosion.   The 316L stainless steel  primary reactor
 (R-l)  and its attendant slurry circulating loops experienced  pitting type
 corrosion.   The severity of the pitting corrosion was  found to  be  directly
 related to  the affected area operating temperature.   It is  important to  note
 that while  the reactor section, which  operated  between 230°F  and 270°F did
 corrode significantly, there was virtually no sign of  pitting corrosion
 elsewhere in  the RTU where slurry temperatures  were generally maintained
 below  215°F.

     The  observed reactor section corrosion  resulted in several instances
 of  leach  solution seepage from circulating loop  piping during operation at
 temperature and  pressure  and  resulted  in unscheduled unit shutdown.  A
 photograph of a  typical seepage  point  is presented as Figure 9.  Both an
 external  view and a  sectioned  internal view of the seepage point are shown.
As  a result of the observed corrosion, all reactor associated piping was
 replaced with  new 316L materials midway through the operational  phase of
the project and  1s currently scheduled for replacement with titanium
materials prior  to unit reactivation.  Titanium 1s being utilized  at RTU
scale since pipe diameter dictates piping materials of solid metallic
construction.  It has been determined, however,  that at larger scales of
operation plastic lined carbon steel pipe would  be most applicable.
                                     980

-------
Figure 9.  Flush port fitting

-------
       Primary reactor (R-l)  was  thoroughly  Inspected  midway  through  and  at
  the  conclusion  of the operational  phase  of the  project.  The  Internals  of
  the  unit were found  to have experienced  significant  pitting corrosion.  A
  photograph of the  Internals of  the third stage  of R-l, taken  during the
  final Inspection,  1s  presented  as Figure 10.  Due to the extent of the
  observed corrosion, 1t 1s currently planned to  Install a replacement reactor
  of titanium construction prior  to reinitiation of RTU operations.  It is
  important to note that the choice of titanium is based on the relatively
 small size of the RTU reactor.  A larger scale unit would no doubt be
 constructed of acid resistant rubber-lined  brick over a carbon steel shell.

      Overall  RTU project conclusions  are  summarized  below.

 Operation  Results
 1.    The Reactor Test Unit  can be operated  continuously for  testing  of the
 Meyers Process units  for  coal/leach solution mixing,  simultaneous  coal
 leaching and  leach  solution  regeneration, filtration  of leach  solution from
 treated  coal  and water washing of coal on the filter.

 2.    The Input coal from American  Electric Power Service Corporation's
 Martlnka mine  1n  Fairmont, West  Virginia, containing 1* Inorganic sulfur
 can be reliably and continuously reduced, 1n the RTU, to a pyritic sulfur
 level of 0.16% without any measurable coal loss and with coal heat content
 Increases averaging 350 Btu/lb.

3.   RTU coal  product, after bench-scale  extraction of residual sulfate and
elemental sulfur, was  continuously and reliably reduced  to a  total  sulfur

-------
1C
DC
ill
                                                          R-l Cel

                                                            Surface
                                                            Pitting
                                                          (reworked area)
                                                R-l Cel

                                                   Weir

                                                  Corrosion
                                      Figure 10.   Primary  reactor internal  corrosion

-------
  content of 0.68-0.75* w/w and projected SOX emissions  levels  of  1.0-1.2
  Ib S02/106 Btu.
  4.    Leach  rates  1n  the  RTU were  Improved over bench-scale values by an
  average  factor of 5, due mainly to favorable coal segregation 1n the
  primary  reactor.

  5.   Plant Teacher/regenerator operation at temperatures ranging 230° to
  270°F (110° to 132°C), pressures of 30-80 pslg and residence times  of 5-8
 hours was successfully demonstrated.

 6.   The use of a  single  reactor/regenerator was  found  to  be  sufficient to
 meet design  basis  pyrlte  removal and  provide regenerated leach solution for
 the  Martlnka coal  tested.   It  1s not  known whether the  use of a  secondary
 reactor  to complete the reaction of pyrlte with leach solution will be
 needed for processing of coals with higher pyrltlc sulfur  content.

 7.   The  leach solution/coal/oxygen environment caused corrosion 1n the
 primary reactor/regenerator system Indicating that upgrading of the 316L
material  of construction Is needed to support further testing.

8.   The following materials were found to be suitable for leach  solution/
coal  service at temperatures up to 90°C:  fiber reinforced plastics,
elastomers and 316L stainless steel.   The following materials  were deter-
mined to be suitable for service at reactor/regenerator  temperatures up to
130°C:  titanium, Hastalloy, and rubber-lined brick over mild  steel
                                    984

-------
9.   No significant corrosion was observed in the leach solution/coal  mix
tank, flash-down tank, or storage tanks.  Mild corrosion was observed  in
the reactor/regenerator pumps.

Supporting Experimentation Results
1.   The iron sulfate/sulfuric acid leach solution can be used as a homo-
genous liquid to efficiently gravity-separate fine coal at specific
gravities of 1.2 to 1.35.

2.   Beneficial engineering  cost  improvements are obtained by using this
gravity-separation technology to  bypass a significant  portion of the  input
coal around the reactor, elemental sulfur extraction and dryer units  of
the  Meyers Process.   This revised process is  termed the Gravichem  Process.

3.   The Gravichem Process  provides  two products with  no coal reject, a
float  coal containing 2-4%  ash with  almost  no pyritic  sulfur and a sink
coal generally  lower  1n  ash than the input  coal  and also nearly  pyrite-
free.   The two  products  can be used  separately or  combined.

4.   Bench-scale  testing of the  Gravichem Process  on  the American  Electric
 Power  Service Corporation (Appalachian) coal  gave  two products:   a float
 coal containing 1.0  Ib S02/106  Btu and a  sink coal  containing 1.1  Ib  S02/
 106 Btu after treatment by the  Meyers Process.  Both  products met present
 New Source Performance Standards.

 5.   Bench-scale testing of the Gravichem Process on a Tennessee  Valley
 Authority (Eastern Interior Basin) coal containing 12% ash  and 7  Ib
                                      985

-------
  S02/10  Btu gave two products:   a 4% ash  float coal  containing  3  lb  SO  /106
  Btu  and  a  sink  coal  containing  4 Ib  S02/106  Btu and  11-12% ash  after treat-
  ment by  the Meyers Process.

  6.    The solvent system, acetone and water,  is  the most economically
  attractive method thus far investigated for  removal of generated elemental
  sulfur from  treated coal.  This  solvent also dissolves and removes residual
  Iron sulfate.

 Engineering Design Results
 1.   Process cost forecasts  for the Gravichem Process are  $68-69/KW capital
 cost  with $0.44-0.50/1O6  Btu  processing costs (including utility financed
 capital  amortization  for  input  coal  costing $0.78-0.81/106 Btu).

 2.    Coal energy efficiency is 94-97%  for  the Gravichem Process  including
 coal  used for process heating.

 3.    Overall  energy efficiency including both coal use and electric energy
 for plant operation is 93-96%.

 PROJECT STATUS
      In early 1978, the RTU coal desulfurization unit was  secured for an
 extended shutdown period at the direction of the EPA.   The  extent of the
shutdown period 1s currently unknown.  Other aspects of the coal  desulfuri-
zation project at TRW are continuing, however.  Currently,  work 1s focused
on the further development of the Gravichem Process.   The current efforts
Involve the accomplishment of additional bench-scale experimentation  full
                                    986

-------
scale process engineering analyses, user specific applications studies, RTU
equipment redesign and specification, RTU tail-end unit design, and RTU
equipment preservation and maintenance.

     In anticipation of restart of the RTU at a future date, the unit is
being preserved and maintained in a standby condition to prevent corrosion
and to limit system deterioration.  The plant has been cleaned of residual
leach solution and coal by flushing with water.  Where appropriate, preser-
vatives were added to protect against corrosion.  All electrical equipment
was shutoff and tagged; Instrumentation was sealed and dessleant added.
Liquid and solid wastes were hauled away.  A detailed plant inspection will
be performed to assess the degree of corrosion that has occurred.  Preven-
tive maintenance of the RTU is being carried out on a weekly basis.  Engi-
neering studies are to be performed which will, 1) establish specifications
for a new reactor vessel R-l and obtain cost estimates and time of delivery
and installation, 2) result in a preliminary conceptual design for an RTU
tail-end unit elemental sulfur extraction system, and 3) evaluate applica-
tion of the Gravichem Process, based on data obtained from bench-scale tests,
for use as a stand-alone plant or as integrated Into a physical coal  clean-
Ing complex.  A respecfflcation of the R-l reactor vessel will be developed
for a replacement vessel to be constructed of material which will give
long-term service.  Designs for a tall-end elemental sulfur extraction
system will Include the use of acetone or methyl ethyl ketone and other
solutions for removal of elemental sulfur at the RTU scale.  Based on an
early tall-end unit conceptual design effort, the RTU tall-end unit expan-
sion 1s envisioned to appear as presented In Figure 11.

                                     987

-------
Figure 11.  RTU tail-end unit expansion
                       988

-------
                               References
Hamersma, J.W.  and M.L.  Kraft (TRW Inc.), Applicability  of the  Meyers  Process
     for chemical  desulfurization of coal:  Survey of thirty-five  coals,
     EPA-650/2-74-025a,  NTIS No.  PB 254461 (1975).

Hamersma, J.W.  et al., Chemical  removal  of pyritic sulfur from  coal, Advances
     in  Chemistry,  Series No.  127, American Chemical  Society,  Washington,
     D.C. (1973).

Hamersma, J.W.  et al.  (TRW Inc.), Chemical desulfurization of coal:  Report
     of bench-scale developments, Volumes I and II, EPA-R2-73-173a and
     -173b, NTIS No.  PB  221405  and 406 (1973).

Hart, W.D. et al.  (TRW Inc.), Reactor test project for chemical removal  of
     pyritic sulfur from coal,  Draft Final Report, EPA Contract No.  68-02-
     1880 (1978).

Koutsoukos, E.P. et al.  (TRW Inc.), Meyers process development  for chemical
     desulfurization of coal, Volume I,  EPA-600/2-76-143a, NTIS No.  PB
     261128 (1976).

McGee, E.M. (Exxon Research and Engineering Co.), Evaluation of pollution
     control in fossil fuel conversion processes, coal treatment:   Section
     1, Meyers  Process,  EPA-650/2-74-009K, NTIS No. PB 246311 (1975).

Meyers, R.A. (TRW Inc.), Coal desulfurization,  Marcel Dekker, Inc.,  New
     York (1977) pp 59-164.

Nekervis, W.F.  and E.F.  Hensley (Dow Chemical Corporation), Conceptual
     design of a commercial scale plant for chemical desulfurization of
     coal, EPA-600/2-75-051, NTIS No. PB 238199 (1975).

Van Nice, L.J.  and M.J.  Santy (TRW Inc.), Pilot plant design for chemical
     desulfurization of coal, EPA-600/2-77-080, NTIS No. PB 270111 (1977).
                                   989

-------
                        Metric Conversion Factors

     In compliance with EPA policy, metric units have been used extensively
in this paper.  However, in some cases, British units have been used for
ease of comprehension.   For these cases, the following conversion table is
provided:
                British

                1  Btu
                1  Btu
                1  KW
                1  hp (electric)
                1  psi
                5/9 (°F-32)
                1  inch
                1  ft
                1ft2
                1  ft3
                1  gallon
                1  pound
                1  ton (short)
    Metric

252 calories
2.93 x 10"4 kilowatt-hours
1,000 joules/sec
746 joules/sec
                 o
0.07 kilograms/cm
°C
2.54 centimeters
0.3048 meter
0.0929 meters2
0.0283 meters3 or 28.3 liters
3.79 liters
0.4536 kilograms
0.9072 metric tons
                                     990

-------
                    STATUS OF HYDRO-THERMAL PROCESSING FOR
                      CHEMICAL DESULFURIZATION OF COAL

                E. P. Stambaugh, H. N. Conkle, J. F. Miller,
                        E. J. Mezey, and B. C. Kim
                      Battelle's Columbus Laboratories
                              Columbus, Ohio
                                  ABSTRACT
     Chemical desulfurization of coal is achieved by heating an aqueous slurry
of coal, sodium hydroxide, and calcium hydroxide in a closed vessel at elevated
temperatures and corresponding steam pressure.  Later, the cleaned coal pro-
duct is separated from the spent leachant by a series of liquid/solid separ-
ations and utilized as a source of fuel.  The spent leachant is regenerated
for recycle.

     This paper presents the current status of this technology and the results
of a current study to improve the economic viability of hydrothermal cleaning
by reducing the costs associated with liquid/solid separation and leachant
regeneration.
                                      991

-------
                               INTRODUCTION

          Results from a previous study for the U.S. Environmental Protection
Agency - "Combustion of Hydrothermally Treated (HTT) Coals", Contract No.
68-02-2119 - indicated that HTT coals prepared by the Hydrothermal Coal
Process from selected coals are clean solid fuels that in many instances
can be burned with little or no sulfur emissions.  Also, the HTT coals burn
as well or better than raw coal and trace metal emissions should be signifi-
cantly reduced because of the low concentrations in HTT coals.
          This work is being continued under the program entitled "Process
Improvement Studies on Battelle Hydrothermal Coal Process" (EPA Contract No.
68-02-2187).  Under this program, emphasis has been on development of process
improvements in the liquid/solid separation and leachant regeneration segments
of the process.  In the liquid/solid separation, laboratory and miniplant
tests were performed to evaluate improvements which can be achieved by
the use of larger coal particle sizes in combination with vacuum and
centrifugal filtration and oil agglomeration.  In leachant regeneration, a
number of potential methods have been screened.  Primary emphasis has been
on the use of metallic compounds containing zinc and iron.
          Technical progress during this contract are discussed in this
paper.

                           Process Description

          The Battelle Hydrothermal Coal Process (BHCP) is a method for pro-
ducing environmentally acceptable solid fuels (clean coal) from high sulfur
coals.
          Basically, hydrotheraal coal processing involves heating an aqueous
slurry of  coal and  a  chemical  leachant,  in  this  case,  a mixture  of  sodium
hydroxide  and  lime  at moderate temperatures and  corresponding steam pressures
to extract the sulfur and 'some of  the  ash from the  coal and subsequent  re-
                                       992

-------
generation of the leachant for recycle.  The process entails five major
processing steps as shown in Figure 1:
          •  Coal preparation
          •  Hydrothermal  treatment  (desulfurization)
          •  Fuel separation (separation of spent leachant from clean coal)
          •  Fuel drying
          •  Leachant regeneration.
          Coal preparation entails crushing or grinding of the raw coal, as-
received from the mine or after washing.
          The coal is then mixed with  the leachant, or, alternatively, the
coal may be physically beneficiated to remove some of the ash and pyritic
sulfur before mixing with  the aqueous  leachant.
          After mixing with the leachant, the coal slurry is pumped contin-
uously through the hydrothermal treatment (desulfurization) segment where it
is heated to a temperature and corresponding steam pressure necessary  to
extract  the sulfur.
          The resulting  coal-product  slurry is  then  cooled  and the cleaned
coal  is  separated  from the spent  leachant by a  series of washing - filtration
operations.
          Next,  the desulfurized  product is dried to reduce the  residual
moisture to  the  desired  level.
           In the basic process, the  spent  leachant is  regenerated for  recycle
by  the C02-CaO  process.   This  entails sparging  the spent  leachant with
 carbon dioxide  to  liberate the sulfur as hydrogen sulfide,  which is  sub-
 sequently converted  to elemental  sulfur by the  Claus or Stretford process.
 The carbonated  liquor  is then causticized  with lime and filtered to  remove
 the calcium carbonate which  is calcined to produce lime and carbon dioxide
 for recycle.   The  regenerated leachant is  concentrated and recycled to the
 process.

                             Process Chemistry

 Sulfur Extraction

           Sulfur is contained in coal in primarily  two forms — inorganic
 sulfur as FeS   (pyrites) which is associated with  the  mineral matter  and

                                        993

-------
VO
VO
                Coal-
                                                             r
                                                                Water
                                                                           Steam
Co*
Preparation

— »»

Hydrotharmal
Treatmant
(OMulfurization)
i
COj
Lime


-~

Racy da
Laachant
Separation
and Washing

Solid

Spent Leachant 1
dean Coal
Sulfur
Removal

»

Laachant
Recovery
— fc-HjS
— •». CaCO3
	 •*• Water
Vanor
                 FIGURE 1.   FLOW DIAGRAM OF THE BASIC HYDROTHERMAL COAL PROCESS

-------
organic sulfur which is part of the coal molecule.  During treatment of the
coal by hydrothermal leaching, up to about 95 percent of the inorganic
sulfur is extracted from most coals and up to 50 percent of the organic
sulfur is extracted from some coals.
          The dissolution or extraction of the inorganic sulfur from coal
using alkaline leaching may involve several chemical reactions including the
following:
          (1)  FeS2 + OH~ -»  Fe(OH)2 + S2~2
(2)   2FeS2 + 60H~ J Fe^ + S2~  + 2S
(3)   3FeS2 + 80H~ £ Fe^ + S2~2 + 2S
                                               ~2
                                               ~2
          However, experimental studies on leaching of coal at Battelle have
demonstrated that sulfur species found in the spent leachant is sodium
sulfide, Na2S, if the leaching is carried out to eliminate oxygen from the
system.  This data would indicate that the sulfur extraction mechanism may
be as follows:
          (A)  FeS2 +2NaOH -»• Fe(OH>2 + Na S_
          (5)  Na2S2 + Fe(OH)2 ->• Fe^ + Na2S
or        (6)  Na2S2 + coal ->- C02 + Na2S.
In Reaction (4j, the pyritic sulfur is extracted as the disulfide.  The
disulfide is then chemically reduced to form the sodium sulfide (Na.S) by
the ferrous hydroxide [Fe(OH)2] (Reaction 5) or by the carbon in the coal
(Reaction 6) .
          Mechanism for extraction of organic sulfur from coal has yet to
be resolved.  This could occur by cleavage of carbon to carbon or carbon
to sulfur bonds.  A simple organic sulfur compound (CH3 - S - CIO has been
identified in the gases evolved during desulfurization of the coal.
                                    995

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Leachant Regeneration

          As discussed above under desulfurization mechanism, the spent
leachant contains sulfide sulfur as Na.S which must be removed in order to
recycle the leachant.  One approach for achieving this is by the CO.-CaO
prpcess.  This involves
          (1)  Liberation of the sulfide sulfur as H2S by carbonation
               according to the following reactions
               NaOH -I- Na2S + C02 ^2>  H2St + NaHCOj
               NaHCO_ + A -»• Na_CO_ + C0«.
          (2)  Regeneration of NaOH by treatment of solution from
               (1) above with lime.
               Na2C03 + CaO •* CaC03 + NaOH.
          (3)  Regeneration of CaC03 for recycle by thermal
               decomposition
               CaC03 + A -»• CaO + C02t.
Other potential approaches will be discussed later.

                           Process Improvements

Leachant Regeneration

          The sodium sulfide  (Na2S) must be  removed prior  to recycle of
the leachant.  If not, the build-up of Na2S  will result  in successively
lower  sulfur extraction as the leachant is recycled.
          Under  this program,  a  number  of  potential  regenerates for regenera-
tion of  the  spent  leachant have  been  screened:
           (a)  Zinc  Oxide   (ZnO)
           (b)  Sodium  Zincate  (Na2Zn02>
           (c)  Metallic Zinc   (Zn)
                                    996

-------
          (4)   Metallic Iron  (Fe)
          (5)   Ferrous Oxide  (FeO)
          (6)   Ferrous Hydroxide [Fe(OH>2]
          (7)   Ferroso-ferric oxide   (Fe30.)
          (8)   Ferric Oxide
          (9)   Ferric hydroxide  [Fe(OH>3]
         (10)   Hydrogen reduced/Oxidized Iron Oxide
         (11)   Sodium ferrite  (Na2Fe02)
         (12)   Ferrous Carbonate  (FeCO,)
         (13)   Activated Carbon .

          Effectiveness of Regenerates.  A number of regenerates were found
to be effective in removing greater than about 85 percent of the total sulfide
sulfur from the spent leachant.

          Zinc-Containing Materials.  The addition of zinc oxide, sodium
zincate and metallic zinc to the spent leachant results in the formation of
an insoluble zinc sulfide.  As noted in Figure 2, zinc oxide at ZnO/S
ratios of 1.25 to 1.75 resulted in the removal of greater than 85 percent
of the sulfide sulfur in approximately 20 minutes at 80 C.  At a ZnO/S
ratio of 3, 100 percent of the sulfide sulfur was precipitated in less than
10 minutes.  At 40 C, ZnO was still effective, but longer time was required
to achieve a high degree of sulfide removal.  Zinc metal was also effective.
However, larger Zn/S ratios were required because of the lower surface area.

          Iron-Containing Compounds.  A number of iron-containing compounds
have been investigated for Regeneration of the spent leachant.  Of these,
iron hydroxides, reduced/oxidized iron  oxide, and ferrous carbonate
are the -most effective as noted in Figure 3.
          Ferrous carbonate  (FeCO,) is  the leading candidate.  As shown  in
Figure 4, 80 to 99 percent of  the sulfide sulfur is precipitated in  less than
15 minutes depending on the Fe/S ratio  and source of FeCO..
           The  use of the  carbonate  makes use of known chemistry.  The
 sulfide  sulfur is precipitated from the spent leachant by the following
 reaction:
                                      997

-------
                                                  Temperature 80 C
                                               O  Zn 0/S « I , Zincate
                                               V  ZnO/S * I , ZnO
                                               D  ZnO/S= 1.25, ZnO
                                               O  ZnO/S- 1.75, ZnO
                                               X  Zn 0/S * 3, ZnOe
                                                  Temperature 40 C
                                                  ZnO/S= I, ZnO
                                                  ZnO/S= 3, ZnO
                                    30
                              Time , minutes
FIGURE  2 .  LEACHANT REGENERATION WITH ZnO (BATCH REACTION) AND ZINCATE
                                   998

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     100
     90
     80
  S  70


  "o



  1  60
  o  50
  »_
  i^>

  
-------
   100
    90
   80
    70
 .  60
    50
2 40
    30
   20
    10
    Synthetic  Fe 0)3
                                      Natural  Fe €03 {Ball milled)
  FelS  RATIO
+   3
•   10
A   10
O   3
a   i.s
                10       20       30       40
                                 Time, minufes
50       60
                                    70
        FIGURE 4. SULFIDE SULFUR REMOVAL WITH FERROUS CARBONATE
                                     1000

-------
                + (Na2S - NaOH)  -»- FeS4- + (Na_CO  - NaOH) .

The regenerated leachant will contain some Na.CCL.  This  can be removed by
the addition of lime (CaO) which results in the precipitation of an insoluble
calcium carbonate.
          The iron values may be regenerated for recycle accordingly:
                     V
          FeS + 20  - *•  FeS0
          FeSO,  + Na«CO_ •*• FeCO. I + Na.SO.
              4      23       j       Z  4
          FeS + 20. + Na CO  H2   FeCO, + + Na.SO,
                  f.     i  J          J       t  H
          Reduced/oxidized ferric oxide, i.e., a ferric oxide which is
first reduced with hydrogen to a pyrophoric state and then partially oxidized
effectively removes the sulfide sulfur from the spent leachant.  As shown
in Figure 5, 80 to 90 percent of the sulfide  sulfur was removed by contacting
the spent leachant with the reduced oxide for a period of 60 minutes.
          Preliminary results indicate that the spent reduced oxide can be
regenerated for recycle.  As shown in Figure  6, first regenerated iron oxide
was as efficient as the original reduced/oxidized iron oxide.  The material
regenerated the second time showed a slightly lower activity after the re-
duction/oxidation treatment.  However, this may be due to a lower Fe/S ratio—
11 compared to 8.
          Freshly prepared  iron hydroxides  also separate  the sulfide  sulfur
from  the spent leachant.  At room  temperature,  98 percent of the sulfur
 (Figure  7)  was removed  in 1 hour at  an Fe/S ratio of  3 with  ferric hydroxide
When  the reaction  temperature was  reduced  to 0  C, 90  percent of  the  sulfur
was  removed.   At  80 C,  reversal  of sulfide removal was  suggested.   Ferrous
hydroxide appears  to be less  effective than ferric  hydroxide as  shown in
Figure 3.  The primary disadvantage of these materials  is that the spent
hydroxides are not readily regenerated for recycle.

 Liquid/Solid Separation

           The coal product slurry from the desulfurization segment of the
 BHCP contains (1) desulfurized coal and (2)  spent leachant.  This slurry is

                                       1001

-------
     too
      90
   5
      60
   o.
    . 70
   I  60
   £
   c  50
   §  40
   o
   0>
   •o
      30
      20
       10
O
                                                Exposure to
                                                  air, mln	
                     1
O
A
X
D
0
.o
5
5
3
0
 [
15
        0            30          60            90          130
                        Reaction  Time ,  minutes
FIGURE 5.  EFFECT OF THE PERIODS OF EXPOSURE TO AIR OF REDUCED
           IRON OXIDE ON REDUCTION IN SULFIDE CONCENTRATION
                                1002

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   100

    90
•£
o   80
Q>
a
u
 i
    70
    60
o
    so
40

30

20

 10
            I	I
                             O  First  regeneration
                             X  Fresh iron-oxide
                             A  Second regeneration
I	I
                                  I	I
I	I
       0            30           60           90
                       Reaction Time, minutes
   FIGURE 6.  EFFECT OF REGENERATION OF SPENT IRON OXIDE
                                                       120
                                 1003

-------
     100
     90
     80
     70
     60
  0)
  Q.
  o>

 |  50

 (/>

 .5

  c  40
     30
     20
      10
                           20         30        40

                                 Time, minutes
50
60
FIGURE 7.  THE EFFECT OF TEMPERATURE ON LEACHANT REGENERATION WITH Fe(OH}3



                                 1004

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 first filtered to remove the primary filtrate from the cleaned coal product.
 This material is then washed to separate the residual spent leachant from the
 clean (HTT) coal.
           In the initial development of the BHCP, 70 percent minus 200 mesh
 coal was used.  This resulted in a HTT coal containing equal to or greater
 than 50 percent moisture and large quantities of water were required to
 separate the residual spent leachant from the HTT coal.   Also, the liquid/
 solid separations proceeded slowly.
           Analysis of this segment of the process indicated that process
improvements — reduced water consumption and lower water content of the coal
product — might be realized by the use of larger particle size coal.   There-
fore, a study was conducted to
           •  Increase liquid/solid separation rate
           •  Reduce moisture content of HTT coal product
           •  Minimize wash water consumption and
           •  Maximize sodium removal and
 thus determine a near-optimizing separation and washing circuit.  Two sizes
 of coal were examined — 100 percent minus 20 percent and 100 percent minus
 50 mesh.

           Approach.  Because of the large scale nature of the planned appli-
 cation and the slow to moderate separation rate, separation by large, com-
 mercially available equipment was selected for intensive study.  The use of
 filtration aids, surfactants, and oil agglomeration to improve separation
 rates and final cake moisture were also studied.
           Because of the complex nature of the separation and washing
 circuit and its interactions with other cost sensitive sections of the BHCP,
 a computer program was prepared to investigate the relationships between
 the total separation and washing costs and the following processing variables:
           (1)  Separation equipment (vacuum and belt
                filter, plus centrifuge)
           (2)  Separation rates
           (3)  Cake solids content
           (4)  Wash water-to-coal ratio
           (5)  Number of washing stages

                                       1005

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           (6)   Residual unbound sodium.
 Sensitivity studies allowed rapid investigation of  the different  separation
 techniques and showed where the most significant cost saving  could be  obtained.

           Technical Achievements.  Through  the  use of  coarser coals (-20 and
 -50  mesh coal  as  compared to -200 mesh)  and other process modifications,
 significant process improvements were realized.

           Separation  Rate.   When the original -20 mesh solution was tested,
 a  rate  of only 0,008  ton/hr/ft2  was  obtained.   Pretreatment testing was
 first  conducted to  improve  the  rate.   The use of flocculants  resulted  in
 floating  of the fines,  allowing  the  coarser material  to settle.   Consequently,
 the  fines settled on  the  surface of  the  cake, resulting in an effective
 barrier  to further  dewatering.   Dispersants  (sodium lauryl sulfate was found
 most effective) were  found  to solve  this problem  by dispersing the fines
 throughout  the  cake.  Separation rates were increased by a factor of 10 to
 0.08 ton/hr/ft2 at  an addition  level of  0.5 Ib/ton.
          After the initial dispersant addition,  separation rate  was found
 to be primarily dependent on the degree of washing, increasing after each
                                            O
wash until  it leveled off at >0.6 ton/hr/ft .  Results with -20 and -50
mesh HTT  coal are summarized in Table 1,   As noted in the table, the degree
of washing also has a strong  effect  on the  final  moisture content of the coal
 product.

           Moisture Removal.  The original separation tests with -20 mesh
 coal produced a cake with * 59 percent moisture.  The use of dispersants for
 separation rate improvement also improved the moisture removal efficiency
 during separation.   The cake showed lower moisture retention with the smaller
 -50  mesh coal. However,  this trend to less moisture retention with smaller
 particle sizes did  not extend downward to the -200 mesh coal where * 60 per-
 cent moisture  cakes were produced .  Since the separation rates with the -50
 mesh were not  significantly less than with the -20  mesh coal, this size
 range  seemed near optimal for further development work.
           Other measures  to further  reduce the  moisture content included
 oil  agglomeration prior to  separation, solvent  displacement,  and centrifu-
 gation.   The oil  agglomeration  tests showed that increased  separation  rates

                                       1006

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                                    TABLE 1.
           VACUUM FILTRATION RATE AS A FUNCTION OF
                PARTICLE SIZE AND WASHING STAGED
Ground
Rate,
kkg/hr/m2
(ton/hr/ft2)
0.78
(0.08)
0.88
(0.09)
2.93
(0.3)
5.86
(0.6)
>5.9
-20 Mesh
Moisture Level,
percent
53

53

54

54

55
Washing Stage

Initial separation


First wash

Second wash

Third wash

Fourth wash
(a) Vacuum filtration employing 28 in. Hg vacuum. Slurry initially treated with a
    sodium lauryl sulfate dispersant to improve water removal.
Ground
Rate,
kkg/hr/m2
(ton/hr/ft2)
0.78
(0.08)
1.95
(0.2)
2.93
(0.3)
5.86
(0.5)
5.86
(0.6)
-50 Mesh
Moisture Level
percent
48
49
50
51
52
                                        1007

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                 2
of 1.9 tons/hr/fc  could be obtained; however, the moisture content of the
clean coal was reduced by only 1 to 3 percent.  A washing test with a
mixture of toluene and ethyl alcohol was conducted on a high moisture
extensively washed cake.  The solvents effectively displaced the water
from the cake but did not reduce the moisture content of the coal product.
Drying tests with the solvent washed coal showed that drying energy require-
ments were reduced in half as compared to the water washed coal.
          For centrifuge testing, HIT coal was prepared in the continuous
30 Ib/hr miniplant.  A 6-14 bird screen bowl centrifuge was continuously fed
with the miniplant output.  While the centrifuge equipment was considered
too small to generate accurate separation rate data, the test program did
establish that the final moisture content could be lowered to ^ 40 to 42
percent.

          Sodium Removal.  The residual sodium remaining in the treated coal
must be reduced for economic reasons  (for sodium recycle and reuse) as well
as combustion (corrosion) considerations.  The sodium can be removed by dis-
placement or repulp washing.  Displacement washing occurs by the wash liquor
pushing the filtrate ahead of it through the void channels with practically
no filtrate dilution.  In experimental testing, it was established that the
HTT coal cake, due to its compressive nature resulting in low sodium removal
and low separation rates, and thus, was not amenable to this washing technique.
Therefore, emphasis was placed on repulp washing.
          Repulp washing consists of mixing the separated filter cake with
wash liquor and refiltering.  The process eliminates stratified regions in
the cake that are washed at different levels, assures close contact of the
wash liquor and the soluble materials, increases the rate of diffusional
extraction and, with proper media selection, can allow selective removal  of
slow filtering fines.  This method of washing can be incorporated  into a
washing circuit employing almost any  type of separation equipment.  It is
especially suited for counter-current "extraction" washing.  Counter-current
extraction offers the most economical use of wash liquor, permitting high
sodium concentrations in the final extract sent to the evaporator  and re-
                                     1008

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 generation, and high solute recovery from the treated coal with a minimal
 amount of  fresh wash water.  Stepwise counter-current extraction is com-
 mercially  employed for leaching of solids and washing of precipitates.
           The washing scheme developed for HIT coal consists of a number
 of separation stages in series.  Fresh wash water is mixed with the treated
 coal which has been most nearly exhausted of residual sodium.  The fil-
 trate from that operation is advanced progressively from one separation
 stage to the next until the most concentrated solution discharges from the
 separation stage where the fresh HTT coal slurry enters.  Simultaneously
 the separated solids are transferred from one stage to the next in the
 opposite direction finally exiting from the fresh water washing stage.  Be-
 cause of the difficulty of simulating a multistage counter-current washing
 circuit, washing tests were conducted by repulp washing of the separated
 solids with fresh wash water rather than washing with filtrate from con-
 secutive washing.
           The first variable studied was coal particle size.  It was
 theorized  that the smaller particles could be washed easier because more
 of the sodium would be on the surface with less inside the coal particle.
 As noted in Figure 8, the smaller -100 mesh particles were more readily
 washed than the larger particles.  The difference while significant was
 not sufficiently large to stop work on alternate methods of washing the
 larger, more rapidly filtering coal particles.  A series of tests with
 the -50 mesh coal were conducted using a 2 to 1 water-to-coal ratio
 employing  (1) extended (1 hr) mixing time to allow a longer time for dif-
 fusional controlled removal of the sodium, (2) a saturated CO, water wash
 to react with the sodium, and (3) a saturate lime water wash to promote
 greater ion exchange between the calcium and sodium.
          The results are displayed in Figure 9.  Clearly the saturated lime
water wash was superior to the standard washing results.  Apparently  the
 dissolved  calcium in the lime water promoted effective exchange with  the
 sodium.  In fact, the bound sodium (sodium not removable by extensive wash)
was lowered from ~ 0.5 to ^ 0.1 percent.  This result was especially  signifi-
                                    1009

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                    - 20 Mesh
                    -50 Mesh
                    -100 Mesh
           0   2   4    6   8    10   12
           No. of Fresh Wbter Washing Stages
FIGURE e.  SODIUM REMOVAL VERSUS NUMBER OF WASHING
        STAGES AS A FUNCTION OF STARTING COAL
        PARTICLE SIZE
                      1010

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                       Standard wash

                      Extended repulp (1-hr)
                          Sat. C02-wa1er wash
                 Sat lime's
                 water wash
                0   2   4    6   8   10    12

                 No. of Fresh Water Washing Stages

FIGURE 9.  SODIUM REMOVAL VERSUS NUMBER OF WASHING
        STAGES FOR -50 MESH HIT COAL AS A FUNCTION

        OF SPECIAL WASHING METHODS
                            1011

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 cant  since  it  allows removal  to  the desired 0.5 percent total sodium level
 with  a  reasonable number of washing stages and impregnates the coal with a
 sulfur  getter.

          Wash Water Usage.   The final variable needed to complete the L/S
 separation  circuit design was the wash water-to-coal ratio.  This is a com-
 plex  variable because of its  many interactions with the rest of the BHCP.
 The ratio chosen will effect  the size of the separation equipment, number of
 stages, size and number of pumps and piping, downstream storage requirement
 as well as  evaporation and regeneration requirements.  Therefore, the wash
 water-to-coal ratio was selected by computer simulation.  However, before
 the simulation could be conducted, a correlation between theoretical and
 actual  sodium removal in a counter-current extraction* circuit was required.
 Because multistage counter-current extractions are difficult and time con-
 suming  to conduct washing tests were conducted with fresh water.  It was
 found that  approximately 2.5  actual stages were necessary to obtain the same
 sodium  removal as predicted by one theoretical stage.  This stage efficiency
 was found to be a constant even up to 10 repulp washes (i.e., 10 repulp
 washes  removed as much sodium as predicted after four theoretical washes).
 With  this information the "optimum" separation and washing circuit was
 designed.

          Washing Circuit Design.  A computerized cost model was designed to
 simulate the separation, washing, and evaporation (prior to regeneration)
 section of  the BHCP.  The model was based on counter-current extraction
washing of  the solution produced in the desulfurization autoclaves.  For the
 initial slow filtering -stages disc filters were selected and for the more
 rapid filtering stages  (fifth and higher), belt filters were chosen,  A final
 stage screen bowl centrifuge  was Included for dewatering to 42 percent
 moisture.   Theoretical  counter-current extraction equations were adjusted
 to allow for the experimentally determined 40 percent stage efficiency.
                                     1012

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          The optimum circuit design depends on the bound sodium level.   A
relatively conservative level of 0.27 percent was specified.  Based on the
experimental data generated, the filter and centrifuge cake moisture content
levels were set at 52 and 42 percent, respectively.  The optimum design,
displayed schematically in Figure 10 consists of a counter-current washing
circuit composed of the following separation elements:
          (1)  Four disc filter stages
          (2)  Six belt filter stages
          (3)  One centrifuge stage.
A wash water-to-coal ratio of 1.75 was required to produce a final product
with 0.47 percent (moisture free basis) total sodium.

          Sodium, Ash, and Sulfur Levels.  Chemical analyses of the raw and
a typical product cake are summarized in Table 2.  Three components are of
special Importance.  First, the total sodium is below the desired 0.5 percent
required for satisfactory boiler operation.  Second, the ash content is
slightly lower than that of the raw coal.  Since both calcium and sodium
levels are higher than in the starting coal, the reductions in ash are due
to removal during the desulfurization step and subsequent downstream proces-
sing.  Finally, and of great importance is the MAF sulfur level.  Since the
process goal is desulfurization, the product coals sulfur content must be
below the NSPS level.  At 0.86 percent MAF sulfur, the coal does meet this
criterion.  In addition, the high residual calcium level has been shown to
lead to in-situ sulfur capture making the combustion off-gas even lower in
SO- than that anticipated from the coal's sulfur content.
                                     1013

-------
Row Story
                                              Solids      nitrate
            Enclosed Rotary Vocuum Disc Filters
                                                                                              Fresh IflfcisJi Water
                                                                                              175 b/t> coal
                                                            Enclosed  Honzond  Vacuum Bdl FUer
                                                                                                  Screen Bowl Centrifuge
          FIGURE  10.     HTT COAL WASHING AND SEPARATION CIRCUIT

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                                    TABLE 2.
          CHEMICAL ANALYSIS OF RAW AND HYDROTHERMALLY
           DESULFURIZED PITTSBURGH SEAM (WESTLAND) COAL
                       HgO     Ash, MF
-------
               SURVEY OF COALS TREATED BY OXYDESULFURIZATION

       R. P. Warzinskl, J. A. Ruether, S. Friedman, and F. W. Steffgen
                         U.S. Department of Energy
                     Pittsburgh Energy Technology Center
                          Pittsburgh, Pennsylvania
                                  ABSTRACT
     The feasibility of using only compressed air and water at elevated
temperature to reduce the sulfur content of coal has been demonstrated in
autoclave experimentation at the Pittsburgh Energy Technology Center for
various coals from most of the major coal basins in the United States.  This
air/water oxydesulfurization consistently removes in excess of 90 percent
of the pyritic sulfur and has the potential for reducing the organic sulfur
content by up to 40 percent.  The sulfur liberated from coal by this reaction
is present in the aqueous effluent as dilute sulfuric acid which can be
neutralized with limestone.  Under certain reaction conditions pyrite forms
a jarosite intermediate which reports as organic sulfur in chemical  analysis.
Extent of organic sulfur removal and loss of heating value increase  with
temperature in the range 170°-200°C.
                                    1016

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                        INTRODUCTION
Precombustion removal of sulfur and minerals from coal by
physical/chemical cleaning is a developing technology that will
provide alternate approaches to the electric utility industry
and industrial boiler installations for complying with EPA
New Source Performance Standards (NSPS) and future revisions
without relying totally on flue gas desulfurization (FGD)
(Friedman and Warzinski, 1977).  These approaches could vary
from physical/chemical cleaning alone to combining it with FGD.
A combination approach could potentially reduce capital and
operating costs by increasing reliability, reducing duplication
of equipment needed to achieve present reliability, improving
feedstock uniformity, reducing trace elements and ash constituents
responsible for deposits and corrosion, and reducing sludge
disposal problems.   (Engdahl and Rosenberg, 1978; Balzhiser, 1978).
     The only methods of coal cleaning practiced commercially  are
physical methods which utilize density differences and surface
properties to achieve separation of coal and associated minerals.
At an  acceptable level of  fuel value loss  physical cleaning  removes
only accessible pyritic sulfur, leaving behind  that which is finely
                              1017

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divided throughout the coal matrix and sulfur chemically bound to
the organic coal matrix.  Therefore, only a small percentage of
coals can be brought into compliance using only physical cleaning.
On the other hand the selective chemical removal of sulfur
from coal is capable of approaching complete pyritic sulfur
elimination and, depending on the process, removal of the reactive
organic forms of sulfur in coal.
     A variety of chemical cleaning processes are under development
and have been reviewed in the literature.  (Friedman and Warzinski,
1977; Oder, et.al., 1977; Versar, Inc., 1978; Meyers, 1977).  This
report deals with the developmental research of one of these tech-
niques, air/water oxidative desulfurization  (termed Oxydesulfurization).
     Air/water oxidative desulfurization has been demonstrated in
autoclave experiments for various coals representative of the
major U.S. coal basins  (Friedman and Warzinski, 1977).  The reaction
proceeds most effectively at temperatures of 150 to 200  C
at a total system pressure of 3.5 to 10.4 MPa  (500 to 1500 psig).
Above 200° C, coal and product heating value losses become sub-
stantial due to the oxidative loss  of carbon and hydrogen.  The
pyritic sulfur  solubilization reactions are  typically complete
 (95 percent removal) within 15  to 40 minutes at temperature;
however, significant organic sulfur removal  requires residence
 times as long as  60 minutes at  the  higher temperatures.  The
principal  products of the reaction  are  sulfuric acid and iron
 oxide.  Several samples  of coals treated by  air/water oxidative
 desulfurization were exhaustively extracted  with  toluene which was

                               1018

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then removed on a rotary evaporator.   No elemental sulfur was
detected.
     Although little is known of the organic sulfur reactions
(Friedman, LaCount and Warzinaki, 1977), the pyrite/air oxidation
reaction in aqueous media has been studied extensively by Vracar
and Vucurovic (1970, 1971, 1972) in relation to producing sulfuric
acid from pyrite for use in ore extraction.  The following reactions
were proposed for finely ground pyrite based upon conditions
similar to those used for coal by Friedman and Warzinski  (1977) .
          2FeS2 + 702 + 2H20 •* 2FeS04 + 2H2S04               (1)
          2FeS04 + 1/202 + H2S04 + Fe2(S04)3 + HgO          (2)
                 )3 + nH20 •* Fe203- (n-3)H20 + 3H2S04        (3)
             )3 + 14H20 + 2Fe3(S04)2(OH)5'2H20 + 5H2S04     (4)
     Above 140° C no elemental sulfur was observed.  Small amounts
of the basic jarosite salt  (reaction 4) were formed at lower
pH and temperature.  Vracar and Vucurovic (1972) observed that for
a 20 gm/1 pyrite slurry under the conditions 200° C, 0.61 to 1.02 MPa
(74-133 psi) oxygen partial pressure, and 3 hour residence
time, pyrite was completely converted to sulfuric acid and iron
oxide.  At temperatures below 200°  C small amounts of unreacted
pyrite, ferrous, and ferric sulfate were present.  The pyrite
reaction rate was found to  be first order in unreacted pyrite
with an activation energy of 51.0 kJ/mole  (12.2 kcal/mole) .  In
a more recent kinetic study, Slagle (1978), using  an Upper Freeport
coal under similar conditions, also found  the  pyritic  sulfur reaction
to be first  order in unreacted pyrite with an  activation energy
of 46.7 k J/mole  (11.2 k cal/mole) . The organic  sulfur  data were
                                 1019

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scattered, but were fitted to a zero order rate expression with an
activation energy of 78.7 k J/mole  (18.8 k cal/mole).  Broader
reviews of pyrite oxidation and coal sulfur oxidation have been
published by Meyers (1977) and Slagle (1978) covering reaction
temperatures and pressures outside  the ranges utilized for air/
water oxydesulfurization.
                        EXPERIMENTAL
     Air/water Oxydesulfurization coal screening experiments
consist of treating a slurry of 35  gm of 200 x 0 mesh coal in 100
ml distilled water contained in a glass, teflon, or stainless steel
liner inserted into a one liter, magnetically stirred, 316 stain-
less steel autoclave.   The autoclave system can be operated in
batch or semibatch modes.  In the batch mode the autoclave contain-
ing the slurry is pressurized with  air at room temperature to the
desired oxygen partial pressure and subsequently heated by a
jacket type heater to reaction temperature at a rate of approximately
3° C/minute.  The slurry is agitated at 900 to 1000 RPM with a
3.175 cm diameter gas dispersion turbine-type impeller.  Reaction
temperature, once reached, is stabilized to within + 2° C by a
proportioning temperature controller and manually operated internal
water cooling coil.  After the desired residence time at reaction
temperature, the cooling coil is used to quench the reaction by
lowering the temperature at a rate of approximately 50 to 60° C/
minute.  When the autoclave reaches room temperature a gas sample
is taken and the product slurry removed.
     The product slurry is filtered through Whatman 541 paper in
a Buchner funnel and washed with distilled water until the pH of
                                1020

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the filtrate tests 4 to 5 with litmus paper, normally requiring
about one liter of distilled water.  The product coal is extracted
on a Soxhlet with distilled water until all soluble sulfates are
removed, as determined with barium chloride.  Analyses of the
initial filtrate and Soxhlet washings indicate greater than 90
percent of the soluble sulfur compounds are removed from the
product coal in the first wash.  The coal sample is finally
vacuum dried at 110° C for approximately 2 hours, weighed, and
sent for analysis.
     In the semibatch mode of operation a constant air flow in
the range of 52 to 208 liters/hour (STP) is used to maintain con-
stant system pressure and essentially constant oxygen partial
pressure throughout the reaction.  In order to minimize the
evaporation and loss of water from the slurry, approximately 70 ml
of distilled water is placed between the reactor wall and the
liner while charging the autoclave to help saturate the effluent
gas.  The autoclave is purged with nitrogen at atmospheric pressure,
closed off, and heated to reaction temperature.  When this temper-
ature is attained the autoclave is rapidly pressurized with air to
the desired operating pressure and the continuous air flow started.
The reaction is quenched by terminating the air flow and using the
internal cooling coil.  Gas samples are normally taken during and
at completion of the reaction.  The product workup is identical
to that of the batch mode.
                               1021

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                      RESULTS AND DISCUSSION
      Twenty-four coals have been treated by air/water oxidative
 desulfurization.  Data for sulfur removal are given In Table
 1,  and the balance of the ultimate analyses are in Table 2.
 All twenty-four coals, unless noted in Table 1, were treated
 for one hour at the temperature indicated under either 5.6
 MPa (800 psig)  initial air pressure in the batch mode or 7.0
 MPa (1000 psig) total system pressure in the semibatch mode.
 An  air flow of  approximately 200 liters/hour (STP)  was used
 in  the semibatch mode.  The mode of operation is also indicated
 in  Table 1.   The first ten coals in the  two tables  would
 meet  the current EPA NSPS of 1.2 Ib SO*  per 10^ BTU.   Due  to
 retention of sulfurous products  in the ash during combustion,
 coals  containing somewhat greater than 0.6 Ib S per 106 BTU
 can be expected to  meet NSPS (EPA,  1977).   Reflecting the
 greater effectiveness  of Oxydesulfurization for removing
 more pyritic than organic sulfur,  all  ten  of the untreated
 coals  had less  than one percent  organic  sulfur.
     Coals  11-17  in the two  tables  had moderate amounts  of
 organic sulfur, up  to  1.5  percent.  Depending  on the  sulfur-
 retention properties of the  ash,  some  of these  coals might
meet NSPS. Relatively  small  improvements in  Oxydesulfurization
processing could  also bring  these coals into compliance.
     Coals 18-24  in the  two  tables had high  organic sulfur
contents, greater than  1.5 percent.  For these  coals significant
improvement  in organic  sulfur removal would be necessary to
bring them into compliance.  However, due to their high
organic sulfur contents, these coals have been used to
                               1022

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                                                             Weight Percent  (Moisture Free)
*
1
3
4
5
6
7
8
9
10
11
1- "
0 "
K) 14
t»> 15
16
17
18
19
20
21
22
23
24
Coal Seam
Black Creek
Imboden
Lower Freeport
Lower Kit tanning
Middle Kittanning
Mammoth
Pittsburgh
Upper Freeport
Upper Freeport
Brookville
Lower Freeport
Pittsburgh
Pittsburgh
Pittsburgh
Whitebrest
Wyoming No. 9
Bevier
Illinois No. 5
Illinois No. 6
Indiana No. 5
4
Mlnshall
Pittsburgh
Mine
Natural Bridge Strip
Peacock
Paramount Elkhorn
No. 1 Strip
Luciusboro Strip
2
Congo Strip
Storm King
Bruceton
Baker
Coal Junction Strip
Humphrey
West Valley Strip
Pitkulski Strip
No. 43 Strip
No. 43 Strip
Lovilia No. 4
Reliance
Ho. 22 Strip
3
River King
Enos
Homestead
Chrisney No. 1
Ireland
State
AL
CO
VA
PA
FA
OH
MT
PA
MD
PA
PA
PA
PA
OH
OH
1A
WY
KS
IL
IL
IN
KY
IN
WV
ASTM
Rank
Mvb
HvBb
HvAb
HvAb
LvB
HvCb
SbA
HvAb
Mvb
Mvb
HvAb
HvAb
HvAb
HvAb
HvBb
HvCb
HvCb
HvAb
HvCb
HvBb
HvBb
HvAb
HvBb
HvAb
»
1.22
1.88
1.19
2.83
0.96
1.08
0.83
1.31
1.58
2.14
4.20
4.14
1.67
3.88
3.01
5.85
1.75
5.00
3.34
3.69
3.27
4.80
5.65
3.89
-Sulfur.
0.65
0.67
0.95
0.75
0.57
0.60
0.57
0.80
0.54
0.63
1.17
1.04
0.89
1.05
0.98
1.07
0.90
1.98
2.03
2.12
1.84
2.34
1.43
2.09
Pyritic
Untr
0.42
0.95
0.26
2.03
0.53
0.26
0.32
0.61
0.82
1.37
3.06
3.09
0.71
2.36
1.93
3.95
0.38
2.92
0.92
1.13
0.70
1.08
3.01
1.38
Sulfur
Tr
0.16
0.10
0.04
0.02
0.08
0.04
0.18
0.05
0.02
0.04
0.13
0.22
0.03
0.19
0.16
0.18
0.06
0.36
0.12
0.11
0.20
0.12
0.10
0.02
Organic
Untr
0.69
0.60
0.78
0.65
0.39
0.78
0.45
0.68
0.56
0.49
1.11
1.01
0.82
1.48
1.05
0.90
1.14
2.04
2.06
2.25
1.98
2.33
1.53
2.18
Sulfur
~~Tr
0.47
0.57
0.79
0.68
0.47
0.55
0.36
0.71
0.50
0.50
1.01
0 78
0.83
0.84
0.80
0.76
0.82
1.60
1.82
2.00
1.64
2.14
1.22
2.03
BTU/lb
Untr
13595
13123
14273
12775
14590
11184
11770
14170
12642
11256
13250
13112
11650
12657
12846
10870
12410
12203
12650
12190
12340
11380
11320
13390
&>
11694
11001
13977
11944
13630
9648
10910
13430
11117
10213
11346
11395
10890
10780
10787
9140
11480
12224
11600
10030
10095
11250
10230
12190
Recovery
94
92
100
99
98
89
92
100
99
95
96
98
100
98
98
81
101
93
90
89
91
93
85
99
IbsS/MM
Untr
0.90
1.45
0.83
2.22
0.66
0.96
0.70
0.92
1.25
1.90
3.17
3.15
1.43
3.06
2.34
5.38
1.41
4.10
2.64
3.03
2.65
4.22
4.99
2.90
BTU
Tr
0.56
0.61
0.61
0.63
0.42
0.62
0.52
0.60
0.48
0.62
1.03
0.91
0.81
0.97
0.90
1.17
0.78
1.62
1.75
2.11
1.82
2.08
1.40
1.71
Reaction
Temperature ( C)
ISO*
2003
150^
ISO3
150,
mo3
150
ISO*
200?
2003
180
180
160
180
180,
150°
150
150
150,
150'
250'
160
200
180
1.  Uncorrelated Coal Seam         2.  Obtained  from Cambria  Slope  Preparation  Plant       3.   Information  Not Available
4.  Blend of Kentucky Seams No. 9, No. 11,  No. 13     5.  Modified Semicontinuous Mode (8-9 SCFH Air Flow)  All others batchflow.
6.  Four repressurizations in batch mode.   7.  1500  psig  Initial  Air  in  batch mode
                                Table  I.  -
                                          8   Untreated  9.

Summary of Coals Treated By Air/Water Oxydesulfurization
                                                                                                         Treated

-------
                              Moisture Free-Weight  Percent
                         Carbon
Hydrogen
Nitrogen
Oxygen
Coal1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
/—
Untr^
3.7
6.5
3.7
15.1
7.1
16.9
9.5
5.5
16.2
22.4
9.3
11.7
21.4
12.7
11.2
17.4
3.2
14.8
8.7
11.6
9.1
14.1
15.9
7.8
" TrJ
2.6
5.2
3.4
13.3
7.0
15.3
7.5
4.6
14.6
21.4
6.6
8.8
20.1
10.4
9.3
16.4
2.1
12.0
6.6
11.0
11.5
11.4
11.1
6.8
Untr
76.9
73.7
80.2
72.5
83.5
64.6
68.4
79.4
72.3
65.0
73.3
73.5
65.4
70.7
72.1
63.0
72.4
68.6
70.8
68.4
69.4
63.8
62.8
73.4
Tr
71.6
68.0
79.6
70.2
79.8
59.6
66.4
76.5
67.7
62.0
68.2
68.2
63.0
66.1
66.1
56.3
69.2
69.3
68.2
61.0
63.4
65.4
63.2
71.0
Untr
5.2
5.3
5.1
4.5
4.4
4.4
4.5
5.3
4.3
3.6
5.2
4.9
4.4
4.8
4.8
4.2
4.7
4.8
5.0
4.6
4.9
4.6
4.6
5.1
Tr
3.8
3.6
4.9
3.9
4.1
3.4
4.0
4.8
3.3
3.0
3.9
3.7
3.9
3.8
3.6
3.3
4.2
4.7
4.3
3.4
3.1
4.2
3.3
4.5
Untr
1.6
1.6
1.5
1.3
1.4
1.2
1.2
1.5
1.3
1.1
1.7
1.3
1.3
1.6
1.8
1.2
1.6
1.1
1.4
1.2
1.6
1.3
1.2
1.3
Tr
1.6
1.9
1.4
1.3
1.4
1.1
1.2
1.5
1.2
1.2
1.4
1.2
1.3
1.4
1.3
1.1
1.5
1.2
1.4
1.1
1.5
1.4
1.3
1.2
Untr
11.4
10.9
8.4
3.7
2.6
11.8
15.6
7.0
4.3
5.9
6.3
4.5
5.9
6.4
7.0
8.3
16.4
5.7
10.7
10.6
11.8
11.3
9.8
8.5
Tr
19
20
9.
10.
7.
20.
20.
11.
12.
11.
18.
17.
10.
17.
18.
21.
22.
10.
17.
21.
18.
15.
19.
14.
.8
.5
9
6
2
0
4
7
7
8
7
0
7
2
7
9
0
8
6
2
7
3
7
4
LSee  table  1.    2Untreated     -"Treated
             Table 2.  - Summary of  Coals  Treated  by Air/Water Oxydesulfurization

-------
 investigate  the removal of organic  sulfur by air/water
 oxidative  desulfurization.
     With  increasing severity of operating conditions,
 increasing amounts of organic sulfur can be removed.  However,
 the organic  sulfur removal is accompanied by heating value
 losses for the coal. This is not surprising, since one would
 expect oxidation of organic structures to proceed at a rate
 at least comparable to that for oxidation and cleavage of
 some C-S bonds.  An organic sulfur  removal efficiency may be
 defined as the ratio of the differential increase in organic
 sulfur removal to the differential  increase in heating value
 loss.  So  defined, this efficiency  is equal to the slope of
 a line describing data as plotted in Figure 1.  The data,
 from Table 1, exhibit considerable  scatter.  It should be
 remembered that, besides temperature variations, the data
 also represent coals of six different ranks, ranging from
 hvAb to sbA.  Slagle and Shah (1978) prepared a similar plot
 for a single coal with variable temperature and observed a
 linear correlation superior to that shown in Figure 1.
     The data in Figure 1 and those of Slagle and Shah
 (1978) were both for a single top size of coal, 200 mesh.
Wheelock et.  al. (1978) have presented data from which plots
 such as Figure 1 may be constructed for top sizes of 200 and
400 mesh.   Such plots reveal a higher organic sulfur removal
efficiency for the larger top size of coal.  This finding
 suggests a surface effect.   In the absence of such an effect
the smaller particles would be expected to exhibit a higher
                               1025

-------
    50
o
UJ

o

u
tr
13



O
o
tr
o

i-
z
Ul
o
tr
UJ
a.
40
    30
    20
 10
                                I
 Reaction

temperature

    °C

  •  150

  A  160

  •  ISO

  o 200

  V 250


    t	
               10      20      30      40

             PERCENT  HEATING VALUE LOSS
                                            50
       Figure I-Organic  sulfur removal efficiency.
                       1026
                                    8-24-78  L-16208

-------
organic sulfur removal efficiency, since the leachant would
have access to a larger fraction of all sulfur contained in
the coal (Medieros and Peterson, 1976).
     The data in Table 2 show an increase in oxygen content
of coal due to processing.  This effect is shown graphically
in Figure 2, where moles of oxygen taken up by the coal per
mole of carbon in the product coal is seen to increase with
loss of heating value.  Hydrogen and carbon in the coal
decrease due to processing.  The data in Table 2 are plotted
in Figure 3.  It is seen, for the range of heating value
loss encountered, between zero and 30 percent, that hydrogen
is preferentially removed from the organic matrix.  Apparently
heating value is lost both by consumption of the coal to
final oxidation products, carbon dioxide and water, and by
partial replacement of hydrogen by oxygen in the coal.
     A beneficial side benefit of Oxydesulfurization treatment
is reduction in the ash content of the coal.  Part of the
ash probably is dissolved in the sulfuric acid formed during
reaction.  Inspection of Table 2 shows a maximum ash reduction
of 41 percent and an average reduction for all coals treated
of 20 percent.
     An interesting effect that has been observed with some
coals is an apparent increase in organic sulfur with oxidative
desulfurization treatment.  An example is shown in Figure 4.
The four experiments shown were made on a Lower Freeport
coal according to the standard procedure for the continuous
air feed mode,  using the reaction conditions listed.  Over 95
                                1027

-------
    20
 o
 o
     16
o


 •


UJ
  o
     12
     8
z
UJ
  O
  CD
'*
 »  / »
            ".i
       .«/•   '
           I
        I
                           I
           10    20    30    40


          PERCENT HEATING VALUE LOSS



      Figure 2-Oxygen uptake by coal due to treat-

           ment .
                                50
               1028
                       8-29-78 L-16226

-------
LJ
UJ
o:
o
id
o
o
<
or
UJ
A  Hydrogen

0  Carbon
                10       20      30       40

              PERCENT  HEATING VALUE  LOSS
       Figure 3-Carbon and hydrogen loss due

                to treatment .
                         1029
                                        8-24-78 L-16209

-------
E
o»
 •k

UJ
UJ
o:
o
UJ
o

cc
o

UJ
UJ
cr
o
i
o

UJ
•  Total sulfur decrease

a  Pyritic  sulfur  decrease

A  Organic sulfur Increase
                10       20      30      40      50

                   RESIDENCE TIME , minutes
   Figure 4-Apporent  increase in organic sulfur with treat-

            ment. (Lower  Freeport HVAb , I80°C , 1000 psig

            air , 35 g coal  charge).
                            1030
                8-24-78  L-I62IO

-------
percent of the pyritic sulfur is removed in the first 15
minutes, resulting in a total sulfur decrease of 60 percent.
The organic sulfur registers an apparent increase, however,
with the peak value at 15 minutes being 55 percent larger
than the value for the untreated coal.  With longer treat
time the apparent organic sulfur decreases again, the value
at one hour being close to the value for the untreated coal.
     We do not believe that organic sulfur is created during
processing, but rather that the anomalous results are an
artifact arising from the analytical determination of organic
sulfur by difference.  The formation of jarosite-like basic
salts is well known in hydrometallurgy.  One such species is
shown in Equation (4), as suggested by Vracar and Vukurovic
(1970).  Other solids can also be formed in our system,
containing as it does ferrous, ferric, and sulfate ions, and
smaller concentrations of other cations.  Kwok and Robins
(1973) have reviewed the formation of so-called thermal
precipitates in aqueous solutions.  Some of their data
showing the formation of thermal precipitates in aqueous
ferrous and ferric sulfate solutions are shown in Figure 5.
For solutions with ferrous or ferric concentrations as
indicated by a particular curve, a precipitate forms when
the temperature and pH at 25° C place the system to the
right of the curve.  From calculated concentrations of
ferrous/ferric ions and measured values of pH, we determine
that the formation of thermal precipitates is possible  in
our system.
                                1031

-------
      250
      225
  UJ
  a:
  D
  *-
  <
  tr
  UJ
  a.

  2
  ui
20O  -
o
u>
N>
175 =
       I5O
                             Symbol
                                  Compound

                                  FeS04
                               NoFe3(S04)2(OH)6

                             Fe203 - 2S03 • H20 or

                             3Fe203 • 4S03 • 9H20

                               NaFe3(S04)2(OH)6
                                              • H20
1'    7z    o
 Molal cone of  Fe or Fe
         1.0

         O.I

         O.I

         O.I
         0.01

         0.001
           Figure  5— Thermal  precipitation of iron  compounds in  H2S04 -H20

                     (Na2S04) system.
                                                                    L-16225

-------
     We believe an explanation for Figure 4 is that jarosite-
like compounds are formed in the early stages of reaction in
which the pyrite is nearly completely consumed.  The jarosites
are not the most thermodynamically stable species at reaction
conditions, but may form due to localized fluctuations in
solution concentration in the vicinity of pyrite crystallites
at the time they go into solution.  Kept in contact with the
leachant solution the jarosites digest to more stable forms,
ferric oxide and sulfuric acid, which do not contain sulfur
in the solid phase.
     A thermal precipitate was formed in an experiment in
which a model sulfur compound was subjected to Oxydesulfurization
process conditions.  X-ray diffraction analysis indicated
that the precipitate was jarosite-like.  X-ray fluorescence
showed the major components of the precipitate to be iron
and sulfur.  No sodium was detected by this method or by
atomic absorption.  Therefore, the compound is not natrojarosite,
for which  the equilibrium precipitation  temperature/acidity
diagram is shown in Figure 5, but rather the basic sulfate
as proposed by Vracar and Vucurovic  (1970) in  Equation  (4).
Analysis of precipitate by a Fisher  sulfur analyzer indicated
a sulfur content of 13.4 percent, which  is close to the
theoretical value of 13.34 percent for Fe3(S04)2(OH)5*2H20.
     To test  the possibility that jarosite-like  compounds
are responsible for apparent organic sulfur  increase, a
sample of  an  Upper Freeport seam  coal was  doped  with  the
collected  jarosite-like precipitate  and  submitted  for analysis.
                              1033

-------
All  of the  sulfur  in  the  doped  coal,  including  the jarosite
sulfur, was determined by the ASTM Eschka method, but only
86 percent  of jarosite sulfur was  reported as sulfate sulfur.
None was  reported  as  pyrite; the 14 percent balance, therefore,
reported  as organic sulfur.  The organic sulfur in the doped
sample, as  a result,  was  37 percent higher than normal.

             TOWARDS A COMMERCIAL OXYDESULFURIZATION PROCESS
     Work is continuing at the  Pittsburgh Energy Technology
Center to move chemical coal cleaning to a commercial reality.
To this end a continuous  reactor has been built and operated
within the  past months to conduct  air/water oxidative desulfurization.
A slurry  bubble column reactor  is  employed, consisting of a
vertical  tube 2.22 cm inside diameter by 183 cm long.
Preheated air and aqueous coal  slurry are fed to the reactor
cocurrently  at the bottom.  The treated coal slurry and exit
gas  are removed at the top.
     Operation of the continuous reactor to date has been
encouraging.  Using an Upper Freeport coal (number 4 in
Tables 1  and 2) at conditions of temperature and pressure as
established  in the autoclave work,  some results were as
follows.  For a slurry space time of 6 minutes,  the weight
percent total sulfur was reduced from 1.82 in the feed coal
to 0.87 in the product coal.  With a slurry space time of 69
minutes the weight percent total sulfur in the product was
0.70.  Slurry space time is defined as reactor volume divided
by volumetric slurry feed rate.

                              1034

-------
     A more complete account of operations with the continuous
reactor will be made at a later time.   Our experience to
date however, has enabled us to develop a conceptual flow
sheet for an Oxydesulfurization process.  It is shown in
Figure 6.  The flow sheet can be considered in three sections:
coal preparation, reaction and coal recovery, and acid
neutralization.
     In the coal preparation section run of mine coal is
subjected to a number of conventional physical coal cleaning
operations to remove white rock and some separable pyrite.
These cleaning operations employ a grizzly, rotary breaker,
and jig plant. The physically cleaned coal is stored in a
day bin before being sent to a ring mill and ball mills for
grinding.  The ground coal is slurried, preheated, and fed
to a slurry bubble column reactor.  Also fed to the reactor
is compressed air.  Spent air/ steam from the reactor is
used in a turbine expander to supply some of the power
required for air compression.  Product coal from the reactor
is filtered, dried, and is then ready for use.
     Effluent water from the reactor, containing sulfuric
acid, is neutralized.  Shown on the flowsheet are steps for
the grinding and storage of limestone.  The acid water and
limestone are combined in the neutralization tank.  By-
product gypsum is removed by filtration, and the treated
water is recycled to the slurry preparation  tank.
     The flow sheet illustrates the complementarity of
physical and chemical coal cleaning methods.  Relatively

                              1035

-------
 ROM
COAL
                                                                                       Slurry
                                                                                               OXYDESULFURIZED
                                                                                                 CLEAN  COAL
                          Bowl
                          mill
                                                     Neutralization
                                                         tank
„     f    CaS04 _.,

  jf f*—J     To disposal
                                 Figure 6-Oxydesulfurization process
                                                                                       6-27-78   L-I6I20

-------
more washable coals would have a higher fraction of sulfur
removed in the physical preparation section; those less
washable would have a more sulfur removed by chemical cleaning.
Also apparent is the simplicity of the process.  Air, water,
and limestone are the only materials required to treat the
coal.
                         ACKNOWLEDGMENTS
     The authors wish to thank Forrest Walker and  the Pittsburgh
Coal Analysis Laboratory for performing the necessary analyses
and the Chemical and Instrumental Analysis  Division  at the
Pittsburgh Energy Technology Center  for the various  analyses
on  the gas,  liquid  and  residue  samples.   We would  also like to
thank Harry  Ritz, who is responsible for  the  construction of
the  continuous  slurry unit now  in  operation and for  preparing
the  process  flow diagram, and Robert B. LaCount for  his  work
in  the early part  of  the research  program.
                                1037

-------
                         REFERENCES

 Balzhiser, E. E. 1978.  R & D Status Report, Fossil Fuel and
     Advanced Systems Division.  EPRI Journal. April. 41.

Engdahl, R. B. and H. S. Rosenberg. 1978. The Status of Flue Gas
     Desulfurization.  Chemtech.  Feb. 118.

EPA. 1977. Coal Cleaning Review. 1(1):1.

Friedman, S. and R. P. Warzinski. 1977. Chemical Cleaning of Coal.
     Journal of Engineering for Power. 99(3):361.

Friedman, S., R. B. LaCount, and R. P. Warzinski. 1977. Oxidative
     Desulfurization of Coal. ACS Symposium Series. 64:164.

Kwok, 0. J. and R. G. Robins. 1973. Thermal Precipitation in
     Aqueous Solutions. International Symposium on Hydrometallurgy.
     1033.

Medieros, P. J. and E. E. Petersen. 1976. Changes in the Pore
     Structure of Coal with Progressive Extraction. Lawrence Berkeley
     Laboratory Report. LBL-4439.

Meyers, R. 1977. Coal Desulfurization. Marcel Dekker, Inc. New York.

Oder, R., L. Kulapadiharom, R. K. Lee, and E. L. Ekholm. 1977.
     Technical and Cost Comparisons of Chemical Coal Cleaning
     Processes.  Mining Congress Journal. 63(8):42.

Slagle, P. and Y. T. Shah. 1978. Unpublished data.

Versar, Inc. 1978. Technical and Economic Evaluation of Chemical
     Cleaning Processes for Reduction of Sulfur in Coal. Prepared
     under EPA contract 68-02-2199.

Vracar, R. and D. Vucurovic. 1970. Oxidation of Pyrites by Gaseous
     Oxygen from an Aqueous Suspension at Elevated Temperatures in
     an Autoclave (I). Tehnika (Belgrade)-RTIM. 25(8):1490.

Vracar, R. and D. Vucurovic. 1971. Oxidation of Pyrites by Gaseous
     Oxygen from an Aqueous Suspension at Elevated Temperatures in
     an Autoclave (II). Tehnika (Belgrade)-RIM. 26(1):68.

Vracar, R. and D. Vucurovic. 1972. Oxidation of Pyrites by Gaseous
     Oxygen from an Aqueous Suspension at Elevated Temperatures in
     an Autoclave (III). Tehnika (Belgrade)-RIM. 27(7):1308.

Wheelock, T. D., R. T. Greer, R. Markuszewski, and R. W. Fisher.
     1978. Advanced Development of Fine Coal Recovery Technology.
     Annual Technical Progress Report to U. S. ERDA under contract
     W-7405-eng-82.
                                1038

-------
               COAL DESULFURIZATION BY LEACHING WITH ALKALINE
                         SOLUTIONS CONTAINING OXYGEN

             R.  Markuszewski, K. C. Chuang, and T. D. Wheelock
                              Ames Laboratory
                           Iowa  State University
                                Ames, Iowa
                                  ABSTRACT
     Hot alkaline solutions containing dissolved oxygen under  pressure were
used to leach sulfur from bituminous  coals  in a small,  stirred autoclave.
The reduction of sulfur content in coal was studied as  a function of  the
stirring rate, leaching time,  temperature,  pressure, and concentration of
alkali.  Under relatively mild conditions,  almost all of the inorganic sulfur
and a significant portion of the organic sulfur were removed.   Dilute
alkaline solutions were more effective than acidic solutions in the removal
of organic and inorganic sulfur, but  the heating value  recovery was somewhat
higher for acidic solutions.  Also, oxygen was shown to be more effective
than air as the oxidizing medium.  Under alkaline conditions,  more organic
sulfur was removed when the oxygen partial pressure was increased. Optimum
values were determined for the concentration of alkali  and for the temperature
of the leaching process, under given  conditions.
                                      1039

-------
                         INTRODUCTION

     Chemical methods for the removal of sulfur from coal have
received wide attention (Friedman and Warzinski,  1977;  Meyers,
1977; Wheelock,  1977; Wheelock,  1978).  Among the more  promising
are processes based on extraction of sulfur by leaching with
aqueous solutions containing dissolved oxygen ( Agarwal et al.,
1975; Friedman et al.,  1977; Tai et al., 1977).  The rate of
extraction can be increased by operating at elevated temperature
and pressure.  Although generally the leaching solutions are
              _r
acidic, either initially or as a result of the generation of
sulfuric acid during the oxidation of pyritic  sulfur, basic
solutions containing ammonia have also been proposed (Agarwal
et al., 1976; Sareen, 1977).  Apparently, the use of basic
solutions allows a significant extraction of the organic sulfur
as well as the pyritic sulfur from coal under milder conditions.
The  leaching temperatures for basic solutions are relatively
low, generally less  than 150CC.  The advantages of using alkaline
conditions for leaching high-sulfur coals were also demonstrated
by Tai et al.(1977).
     A unique chemical desulfurization  (oxydesulfttrization)
process is being developed  at the Ames Laboratory, Iowa State
                              1040

-------
University, which is based on leaching fine-size coal with a
hot, dilute sodium carbonate solution containing dissolved
oxygen under pressure (Wheelock et al. , 1978).  In this process,
sulfur is extracted from coal by conversion into soluble
sulfates. For pyrite the overall conversion reaction appears
to be :
     2  FeS2 + 7.5 02 + 4 H20  =  Fe203  + 4  H2S04.
The pyritic iron remains as an insoluble iron oxide or hematite
(Chen, 1978) .  The sulfuric acid generated in the process is
immediately neutralized by the alkali as follows:
The mechanism for the extraction of a portion of the organic
sulfur has not been established.
     In this work, several high- sulfur bituminous coals were
leached under various conditions .   The effects of important
parameters such as agitation, leaching ti ae , temperature,
oxygen partial pressure, and alkalinity on the process were
studied.  The results will be used to optimize the oxydesulfuri-
zation process.
                         EXPERIMENTAL
Apparatus
     The leaching experiments were conducted in a 1- liter
stirred autoclave reactor (Autoclave Engineers, Inc., Model
AFP 1005) made of Type 316 stainless .steel.  The reactor was
furnished with a removable,  protective liner made of stainless
steel, an electric heating jacket, a proportional temperature
controller, an internal cooling coil, and a pressure gauge.
                               1041

-------
 The contents  of the  autoclave was  stirred by a gas-dispersing
 turbine agitator operated by a magnetic  drive.
 Procedure
      For each experiment,  the autoclave  reactor was  charged with
 40  g.  of coal plus 400 ml.  of the  leach  solution and sealed.
 The desired agitator speed was established,and the autoclave
 was purged with nitrogen  gas  while being heated up to  tempera-
 ture.   When the desired temperature was  reached, the flow of
 nitrogen was  stopped, the autoclave was  vented, and  oxygen
 was introduced into  the autoclave.  The  oxygen partial pressure
 (psia),  the total pressure  within the autoclave (psig), the
 temperature,  and the  stirrring rate were  kept  constant for the
 duration of the  experiment.   Some gas was bled continuously
 from the reactor to prevent any build-up  of gaseous  reaction
 products, while  the system  pressure was kept constant by sup-
 plying  oxygen  on demand.  At  the end of a run, the flow of
 oxygen was stopped, the system purged with nitrogen,  and the
 reactor  cooled.  The  leached  coal was then recovered by filtra-
 tion, dried at 90°C for 1 day, weighed, and analyzed for the
various  forms of sulfur, ash  content, and heating value by
 standard ASTM procedures.
Materials
     Three of the coals used  for leaching came from mines
 located in southeastern Iowa  (Lovilia mine , Big Ben mine ,  and
Scott coal from  the Iowa State University demonstration mine).
 Another was a Western Kentucky coal (No.9 seam) from the Fies
 Mine  in  Hopkins  Co., KY.  The  Iowa coals were  high-volatile
 bituminous coals, high in sulfur content, and  very heterogeneous

                               1042

-------
in composition.  The coals were dried at 90°C for 1 day, ground
and sieved to the desired mesh size, and analyzed prior to
leaching.
Calculations
     The heating value recovery, in percent, was calculated by
the following equation:
     Recovery (%) - (wt. coal recovered) x heating value x 100
                    (wt. coal started) x heating value
     The specific sulfur content (lb.S/106 Btu),  used in the
tabular data, was calculated as follows:

     Specific sulfur content - 	percent sulfur x 106
                               100 x heating value (in Btu/lb.)
     There is a slight difference in the two forms in which the
data are presented.  In the tables, the percent of sulfur reduc-
tion is based on changes in the specific sulfur content
(lb.S/106 Btu); in the graphs, it is based on the change in the
weight percent of sulfur.
                    RESULTS AND DISCUSSION
Effect of stirring rate
     In order to establish the effect of the stirring rate of
the turbine agitator on the amount of sulfur removed from coal
by leaching, Scott coal was leached for 1 hr. by 0.2M sodium
carbonate at 150 °C and 50 psia oxygen partial pressure.  The
results are presented graphically in Figure 1.  The amount of
                                1043

-------
 pyritic and total sulfur extracted from coal  increased steadily
 as the rotation speed was increased from 200  to  1200  r.p.m.
 Between 1200 and 1400 r.p.m.,  the amount of sulfur  extracted
 (both pyritic and total  sulfur)  increased sharply.  For
 agitator speeds above 1400 r.p.m.,  the amount of pyritic
 and total sulfur removed began to level off and  approached a
 constant value between 1800 and  2100 r.p.m.,  being  about 90 and
 63% for pyritic and  total sulfur,  respectively.  Within this
 range,  the amount of extracted sulfur  was  independent  of the
 agitator speed,  indicating that  the rate  of extraction was no
 longer limited by the mass transfer of oxygen through  the
 solution surrounding the  individual particles.
     A similar dependency on stirring rate was  observed by
 Kosikov et al.(1973)  during  their  study of the oxidation of
 pyrite  by air  in  an  autoclave.   In their explanation,   the
 effect  of stirring is  due  to the amount of oxygen dissolved in
 the  solution.  With   increased agitation, the  amount of dis-
 solved  oxygen  increases until it reaches a limiting value
 determined by  Henry's  law.
     The  study of the  effect of agitator speed on the amount
 of sulfur  extracted was repeated at a higher oxygen partial
 pressure,  i.e. 200 psia.   The data shown in Figure 2 indicate
 that above 800 r.p.m.the reduction in total sulfur content
 increased more steeply and then leveled off sooner,  at about
 1200 r.p.m., and at a higher sulfur reduction value, approx-
 imately 67%, than at the lower oxygen partial  pressure of 50
psia.  The reason for the steeper rise in sulfur removal may be
higher solubility of oxygen in the alkaline leach solution at
                              1044

-------
  90

  80

s"70
I 60

G! so
_i
3
W 40
O  30
o

o
LJ
CC
   20
   10
       ~    I    '    I
        0 TOTAL SULFUR
        a PYRITIC SULFUR
          50 psia 02
                                    I
           400     600     1200     1600
                  AGITATOR SPEED, r.p.m.
                                          2000
Figure  1.   Effect  of agitator speed  on the
            removal of sulfur from  coal for
            50 psia oxygen  partial  pressure
   70
 5 60
 8 50
 tr
   40


   30
 9 20
 o

 3 I0
 tr
        • 200 psia
        o  50 psio
                            _L
                                    _L
            400     800     1200     1600

                    AGITATOR SPEED, rpm
_L
                                           2000
 Figure  2.   The  interaction of agitator speed
             and  oxygen partial pressure on
             total  sulfur  removal.
                       1045

-------
 higher pressure.   Thus,  with increased stirring rate the
 mass  transport is  higher for the solution with the greater
 oxygen concentration; as  more oxygen is transported to the
 particle  surface, the reaction can proceed progressively  faster.
 At the plateau,  some mechanism other than mass transport
 through the  external solution is rate-limiting,  and further
 increases  in rotation speed  do not increase  the reaction rate.
 To keep the  leaching independent of the  stirring rate, all
 further experiments  were conducted at 2000 r.p.m.
 Effect of  leach  solution and oxidant
      In the  next  set of  experiments,  the relative effective-
 ness  of alkaline versus  acidic leaching  conditions and of
 pure  oxygen  versus air as  the oxidant were compared.  The four
 run-of-mine  coals, -200  mesh,  were leached for 1 hr.  at  1508C
 and 50 psia   oxygen  partial  pressure.  Under alkaline conditions,
 0.2M  sodium  carbonate was  the leaching solution.   For acidic
 conditions,  pure water was used;  the  sulfuric  acid produced
 during  the oxidation of  pyritic  sulfur provided  the acidity.
 The oxygen partial pressure was  the  same  (50 psia), regardless
 of whether oxygen or  air was  supplied  to  the autoclave.
    The results presented in Table 1 are  averages  for dupli-
 cate runs.  Although  in each case  the recovery in heating
value was  high, it was slightly greater under acidic  than under
 alkaline conditions.   However, it  is apparent that the percent-
age sulfur reduction was  higher for alkaline than for acidic
conditions.  Since the relative merits of air versus oxygen
are more difficult to discern, the data were subjected to sta-
tistical analysis.

                                1046

-------
  Table 1.  Leaching of coals (-200 mesh) wifh water and with
            alkali using air or pure oxygen.
Gas
Type

°2
Air
c
°2
Airc

°2
Air
°2C
Airc

°2
Air
°2C
Airc

°2
Air
°2°
Airc
H.
V.
Btu/lb.
10,
10,
10,

9,
9,
10,
H,
10,
10,
10,
10,
11,
11,
10,
10,
10,
10,
11,
10,
10,
050b
320
260

520
420
530b
003
860
260
140
270b
260
050
520
340
890b
930
180
240
730
Ash
wt.%
20.7
17.1
17.7

23.5
23.6
15.0
11.3
12.5
17.3
18.3
16.9
12.4
14.1
18.2
19.6
18.3
16.6
16.3
21.8
20.6
lb.S/106 Btu
Pyr.
3.08
0.92
1.66

0.56
1.11
3.50
1.18
2.58
0.72
0.81
6.24
1.42
4.15
1.93
2.78
0.89
0.10
0.13
0.08
0.09
Sulf.
1.07
0.51
0.64

0.22
0.22
1.52
0.38
0.34
0.34
0.32
1.86
0.34
0.20
0.22
0.30
0.86
0.37
0.33
0.09
0.10
Org.
0
1
0

0
0
1
1
1
0
1
2
3
2
1
1
1
1
1
1
1
.97
.15
.91

.71
.85
.67
.66
.41
.97
.02
.53
.21
.72
.94
.85
.43
.53
.63
.31
.37
Tot.
5.12
2.58
3.21

1.49
2.18
6.69
3.22
4.33
2.03
2.15
10.63
4.97
7.07
4.09
4.93
3.18
2.00
2.09
1.48
1.56
Tot. S tt.V.
ixeun . ixcco v .
7 7
la /o
(Lovilia
49.
37.

70.
57.
6
3

9
4
(Big Ben
51.
35.
69.
67.
9
3
7
9
Coal)
95.3
94.7

86.9
88.3
Coal)
97.1
92.8
88.2
86.3
(Scott Coal)
53.
33.
61.
53.
(West
37.
34.
53.
50.
2
5
5
6
. Ky.
1
3
5
9
93.9
95.6
93.2
91.7
Coal)
95.7
95.7
89.2
92.9
aLeached 1 hr. at 150°C and 50 psia 0, partial pressure.

 Heating value, ash content, and sulfur distribution of unleached
 coal.
Q
 Leach solution was 0.2M sodium carbonate.
                               1047

-------
     The general conclusion drawn from the statistical analysis
is that the nature of the leaching solution (alkaline or acidic)
has a greater effect on desulfurization than the nature of the
oxidant (air or oxygen).  Specifically, desulfurization is more
effective, at the 99.570 confidence level, under alkaline than
under acidic conditions.  Also, at a slightly lower confidence
level, namely 95%, oxygen can be said to be a better oxidant
than air.
     Closer scrutiny of the data in Table 1 reveals also that
in almost every case both the pyritic and the organic sulfur
contents were significantly lower for alkaline than  for acidic
leaching conditions.  Use of air versus oxygen, however, produced
no discernible difference in the organic sulfur content.  For
the pyritic sulfur content, use of oxygen tended to result  in
lower values than use of air.
     The relative effectiveness of alkaline,  neutral, and acidic
conditions under various oxygen partial pressures will also be
discussed further below.
Effect of leaching time
     The effect of leaching time on the desulfurization of Lo-
vilia coal is presented in Table 2 and in Figure 3.  At 150°C
and 50 psia oxygen partial pressure, prolonged leaching with
0.2M sodium carbonate improved the extraction of sulfur at first.
But after about 1.5 hr., the reduction in total sulfur leveled
off at about 76-79%.  The initial increase in extraction seemed
due to the removal of additional pyritic sulfur, since the
amount of organic sulfur removed appeared fairly constant
                               1048

-------
Table 2. Oxydesulfurization of coal as a function of
leaching time .
Time
hr.
0
0.5
1.0
1.5
2.0
2,5
3.0
H.V.
Btu/lb.
10,175b
9,686
9,601
9,674
9,706
9,414
9,651
Ash
18.6
22.5
23.2
22.6
22.4
24.7
22.8
lb.S/106
Pyr .
3.84
0.92
0.76
0.56
0.39
1.03
0.53
Sulf.
0.92
0.24
0.15
0.25
0.22
0.34
0.22
Btu
Org.
1.02
0.67
0.87
0.55
0.74
0.70
0.48
Tot. S
Redn
Tot. %
5.78
1.83 68.3
1.78 69.2
1.36 76.5
1.35 76.6
2.07 64.2
1.23 78.7
H.V.
Recov.
-
86.9
86.1
81.3
81.6
76.6
80.9
a
 •Lovilia coal (-200/+250 mesh),  leached with 0.2M Na2C03 at 150°C
 and 50 psia 02-
bHeating value,  ash content,  and sulfur distribution of unleached
 coal.
 (from an initial 1.02 lb.S/106  Btu down to an average of 0.67
Ib. S/106 Btu).   At the same time, the heating value recovery
decreased with increasing leaching time.  Thus, the small
advantage in removal of some additional pyritic sulfur was offset
by a higher loss in heating value.
Effect of oxygen partial pressure
     The beneficial effect of increased oxygen partial pressure
on the desulfurization of coal has already been observed in Fig-
ure 2.  A set of experiments was  then  designed to study this ef-
fect over the range of 25-200 psia oxygen partial pressure by
leaching Lovilia and Western Kentucky  coals with  0.2M sodium
carbonate at 150°C.  From the results  shown in Table  3  and in
                               1049

-------
Table 3.
Effect of oxygen partial pressure on alkaline
of Lovilia coal (-200/+250 mesh).
°2
Press. H.V.
psia Btu/lb.
-
25
50
75
100
125
150
175
200
10
9
9
9
9
9
9
9
9
,175b
,522
,600
,588
,619
,449
,716
,676
,618
Ash
18.6
23.9
23.2
23.3
23.1
24.4
22.3
22.6
23.1
lb.S/106 Btu
Pyr.
3.84
0.78
0.76
0.57
0.57
0.93
0.34
0.40
0.36
Sulf.
0.92
0.22
0.15
0.23
0.25
0.22
0.22
0.26
0.23
Org.
1.02
0.91
0.87
0.78
0.83
0.93
0.76
0.69
0.78
Tot.
5.
1.
1.
1.
1.
2.
1.
1.
1.
78
91
78
58
65
08
32
35
37
leaching
Tot. S
Redn.

67
69
72
71
64
77
76
76
-
.0
.2
.7
.5
.0
.2
.6
.3
H.V.
Recov.
-
86.6
86.1
86.2
86.3
86.2
86.9
87.0
84.1
aLeached 1 hr. with 0.2M Na-CO., at 150°C.
b                      ~
 Heating value, ash content,and sulfur distribution of unleached
 coal.
 Figure 4,  it is evident that the reduction in the total sulfur
 of Lovilia coal increased from 67% up to 76-77% by increasing
 the oxygen partial pressure.   The slight improvement can be
 attributed to additional removal of both pyritic and organic
 sulfur.   By contrast,  the improved desulfurization of Western
 Kentucky coal with increasing oxygen partial  pressure was due
 to the increased removal of organic sulfur and not pyritic sul-
 fur (data  shown in Table 4 and Figure 5).   There is no ready
 explanation for this difference in the  behavior of the pyritic
 sulfur of  the two coals.   Lovilia coal  seems  also unique in  that
                               1050

-------
z
UJ

c
UJ
Q.
90



85



80



75



70



65
           I     I	1	1	1	
         Lovilia  Coal -200/ + 250 mesh

                    50 psia  Og press.

                    150°  C.

                    0.2 M  NagCOs
                            Heating
                            Value Recovery
               J_
            Total  Sulfur Reduction
                     _L
          0.5   1.0   1.5  2.0   2.5   3.0


              REACTION TIME, hr.
Figure  3.   Effect of leaching  time  on

            oxydesulfurization  of  coal.
z
UJ
o
rr
    90
    80
    70
    60
 I    I   I    I    I    I   I    I
Lovilia  Coal -200/+ 250 mesh
            150° C  ,  I hr.

            0.2  M  NaC0
          Heating Value Recovery
               Total Sulfur  Reduction
         25     75     125     175


       PARTIAL PRESSURE  OF  OXYGEN

                     psia


Figure 4.   Effect  of oxygen partial pressure
            on  oxydesulfurization of coal.
                     1051

-------
Table 4.  Leaching Western Kentucky Coal (-200 mesh; at
          different oxygen pressures.
°2
Press
psia

50
100
150
200
« 17 AfTh lb.S/10* Btu
Btu/lb. wt.% Pyr. Sulf. Org.
10,
10,
10,
10,
10,
890b 18.3 0.89 0.86 1.43
237 21.8 0.08 0.09 1.32
370 21.9 0.16 0.08 1.22
375 21.9 0.17 0.09 1.15
383 21.8 0.13 0.14 1.12
Tot.
3.18
1.49
1.45
1.41
1.38
Tot. S
Redn.
%
--
53.
54.
55.
56.


3
6
9
5
H.V.
Recov
<
i
--
89
89
89
90
fo

.2
.4
.5
.2
Leached  1  hr.  by  0.2M Na-CO.,  at  150°C.  Data  are  averages  of
duplicate  runs.
Heating  value, ash  content, and  sulfur  distribution  of unleached
coal.
 the pyritic sulfur content was almost never reduced to a level
 below about 0.4%,.   In Western Kentucky coal,  on the other hand,
 the pyritic sulfur was decreased to as low as 0.13%.   For both
 coals,  however,  the heating value recovery was almost unaffected
 by the increased oxygen partial pressure,  remaining at about 86
 and 90% for Lovilia and Western Kentucky coal, respectively.
      The effect  of oxygen partial pressure on the desulfuriza-
 tion of coal was studied also under alkaline, neutral, and aci-
 dic leaching conditions.  The data in Table 5 and Figure 6 are
 for Western Kentucky coal, leached for 1 hr.  at 150°C by 0.2M
 sodium carbonate,  0.2N sulfuric acid,  or water at pressures  from
 50 to 200  psia oxygen.
                                1052

-------
Tjable 5.   Effect of oxygen partial pressure on the leaching of
          coal with alkaline,neutral or acidic solutionsa.
°2
Press
psia
H.V.
Btu/lb.
10,890b
0.2M N£
50
100
150
200
water0
50
100
150
200
0.2N H2
100
150
200
12CO
10,
10,
10,
10,

10,
10,
11,
11,
so4
3
322
368
344
230

885
090
138
148

11,212
11,204
11,185
Ash
18.3

21.7
21.9
22.1
22.9

16.8
16.4
16.1
16.0

15.5
15.6
15.7
lb.S/106
Pyr.
0.89

0.10
0.15
0.20
0.13

0.12
0.13
0.16
0.14

0.10
0.11
0.11
Sulf.
0.36

0.07
0.07
0.09
0.13

0.28
0.27
0.22
0.20

0.44
0.38
0.43
Btu
Org.
1.

1.
1.
1.
1.

1
1
1
1

1
1
1
43

32
21
13
,19

.49
.41
.29
.27

.41
.34
.31
Tot.
3.18

1.49
1.43
1.42
1.45

1.89
1.81
1.67
1.61

1.95
1.83
1.85
Tot. S
Redn.
-
53.
55.
55.
54.
40.
43.
47.
49.

--
1
0
3
4
6
1
5
4

36.7
42.4
41.8
H.V.
Recov.
	
90.0
87.8
86.9
90.2
97.2
95.0
96.7
96.2
98.5
95.9
96.8
 Western Kentucky coal (-200 mesh), leached 1 hr. at 150°C.


 bHeating value, ash content, and sulfur distribution of uncleachd
  coal.


 °Initial solution, becomes acidic as leaching proceeds.
                                  1053

-------
o
Ul
           oc.
           UJ
           ui
           o
           Q
           Ul
           tr
9O


80
o
UJ

-------
     When water was used as the leachant,  the initially neutral
solution became acidic during the leaching process because of
the production of sulfuric acid.  Under these conditions,  the
reduction of total sulfur increased almost linearly with increas-
ing oxygen pressure, from 40.67. at 50 psia to 49.47* at 200 psia
oxygen partial pressure.  When the leachant was initially acidic
(0.2N sulfuric acid), the reduction of total sulfur was less
favorable, ranging from 36.77. at 100 psia, through 42.47. at 150
psia, to 41.8% at 200 psia oxygen partial pressure.
     When 0.2M sodium carbonate was the leachant, the  total sul-
fur  reduction was much higher; however, it seemed to increase only
slightly with increasing oxygen partial pressure, from 53.1  to
55.37».  The amount  of organic  sulfur in the  leached residue was
less than that  for  the  other  leachants and appeared to decrease
with increasing pressure.  The heating value recovery, on the
other hand, was  lower under  alkaline conditions  (87-907e)  than
under acidic  conditions (96-99%).
     It should be noted that none of  the  coal samples  removed
from the autoclave were washed with water after  the  leaching
treatment.   This obviously had an effect  on the  residual  levels
of sulfate  in the leached coal, amounting to about 0.2 lb.S/10
Btu.  In the case of sulfuric acid as  the leachant,  this  effect
was even more noticeable with residual sulfate levels of about
 0.4 Ib. S/106 Btu.  In addition to improving the total sulfur
 reduction,  a washing step would also decrease the ash content of
 the leached coal.  The benefits of washing  leached coal by water
 or by dilute acid were recognized by Tai et al.  (1977).
                                1055

-------
Effect of alkali concentration
     The data in Table 6 and Figure 7 show the effect of the
alkali concentration on the desulfurization of Lovilia coal at
150°C and 50 psia oxygen partial pressure for 1 hr.   With no
sodium carbonate present in the leach solution, the reduction
of total sulfur was 58%.  The presence of even a small amount
of alkali, i.e. 0.05M sodium carbonate, improved the total sul-
fur reduction significantly, to 66%.  Further increases in
alkali concentration resulted in only slight improvement, while
at higher concentrations the reduction of total sulfur even
declined.  The optimum concentration seemed to be 0.15-0.2M
sodium carbonate, resulting in approximately 71% reduction of
total sulfur.  For this same concentration range, the residual
amounts of pyritic, sulfate, and organic sulfur appeared to be
minimum.  Higher concentrations of alkali were also detrimental
to the heating value recovery, causing a decline from 92.7 to
78.9% in the recovery by increasing the sodium carbonate concen-
tration from 0.05 to 0.5M.  Even worse heating value recoveries
were observed at higher alkali concentrations  (Wheelock et al.,
1978).
Effect of temperature
     The results of the effect of the  leaching temperature on
the desulfurization of Lovilia coal are presented in Table 7 and
Figure 8.  With increasing  temperature, the total sulfur reduc-
tion increased at first, then passed through a broad maximum,
after which it decreased at an accelerating rate.  The optimum
temperature range was approximately 120-150°C;  up to  71.4%
                              1056

-------
Table 6.   Effect of sodium carbonate concentration on leaching
          of coal.
Cone.
Na2co3
_ _
oc
0.05
0.10d
1.15d
0.20d
0.25
0.30d
0.40d
0.50d
H.V.
Btu/lb.
10
10
10
10
10
9
9
9
9
9
,418b
,982
,833
,401
,156
,858
,680
,340
,246
,186
Ash
%
18.0
13.4
14.1
17.9
19.9
22.2
23.6
25.8
26.5
27.0
Ib.
Pyr .
3,24
1.08
0.68
0.73
0.62
0.82
1.14
0.82
0.74
0.70
S/106 Btu
Sulf .
0.90
0.29
0.36
0.24
0,20
0.21
0.22
0.28
0.21
0.46
Org.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
99
80
71
72
71
81
93
86
84
80
Tot.
5.13
2.17
1.75
1.69
1.53
1.84
2.29
1.96
1.99
1.96
Tot.S
Redn.
%
--
58
66
67
70
64
55
61
61
61

.0
.2
.4
.5
.4
.7
.7
.2
.9
H.V.
Recov .
%
—
91.7
92.7
89.2
88.2
86.7
86.2
84.4
80.2
78.9
 aLovilia coal  (-200/+250 mesh),  leached  1 hr.  at  150°C  and 50
  psia §2-

  Heating value,  ash content,  and sulfur  distribution of unleached
  coal.

 °Leach solution was initially water;  became acidic as leaching
  proceeded.

 ^Values are averages of duplicate runs.
                                 1057

-------
 Table  7.  Effect  of  temperature  on  the  leaching of coal with
          alkali.
Temp.
°C
--
100
120
130
150°
170
180C
200
H.V.
Btu/lb.
10
9
9
9
9
9
9
8
,047b
,666
,634
,662
,268
,205
,016
,950
Ash
19.6
22 .6
22.9
22.7
25.9
26.3
27.8
28.4
lb.S/106 Btu
Pyr.
3.90
1.25
0.80
0.88
1.42
1.51
1.71
2.69
Sulf.
0.94
0.28
0.29
0.23
0.20
6.27
0.22
0.23
Org.
0.
0.
0.
0.
0.
0.
0.
0.
93
69
56
64
70
59
98
98
Tot.
5.77
2.22
1.65
1.75
2.32
2.37
2.91
3.90
Tot.S
Redn.
--
61
71
69
59
58
49
32

.5
.4
.7
.9
.9
.7
.4
H.V.
Recov.
--
89.7
88.2
89.2
83.6
80.2
75.9
78.2
         10,390b  18.3    3.12    0..94     1.03     5.09   —

.110d  __  9,783   23.1    0.59    0.25     0.89     1.73    66.0     90.2
 aLovilla  coal  (-200/+250 mesh),  leached  1 hr. with  0.2M Na2C03
  at   50 psia 02-

 bHeating  value, ash content,  and sulfur  distribution of unleached
  coal.

 cAverage  of duplicate runs.

  Control  sample for this run  was sample  immediately above.
                                1058

-------
z
LU
O
£C
UJ
0.
                            1 -
         Lovifio  Coal -200/+ 250 mesh
                    50 psia  ©2 pr«ss._

                    150°  C
                      hr.
       _Value Recovery
          Total  Sulfur Reduction
                                   —   Figure  7.
           o.i   0.2   0.3   0.4   as

       CONCENTRATION OF Na2COj,M.
                                                  Effect of  sodium
                                                  carbonate  concentration
                                                  on oxydesulfurizafcion
                                                  of coal.
I-
    100


    90


    80


     70


     so


     50


     40
       r    i    I     r   r     r
        Lovilia  Coal  -200/*250mesh
                  SOpsi Og pressur*-

                  1 hr.

                  0.2M No2C03  -
       Heating
       Value Recovery
       Total        o
       Sulfur Reduction
                            I
                              J_
         100  120  140   ISO  180  200

                TEMPERATURE, °C
                                       Figure 8.   Oxydesulfurization of
                                                    coal  as a function o£
                                                    temperature.
                                    1059

-------
 of the  total  sulfur was  extracted in  this  region.  At  200°C,
 the total  sulfur  reduction had  decreased to  32.4%.  The relative
 reductions in pyritic  and organic sulfur seemed  to parallel the
 reduction  curve for total sulfur.  Only sulfate  sulfur appeared
 to have a  constant residual value of  about 0.2 Ib. S/10  Btu.
 The heating value recovery declined steadily with increasing
 temperature,  from 90%  down to 78%, probably  because of partial
 oxidation  of  coal.
     At the present time,  it is not certain  what causes this
 unusual temperature effect.  It may be due to a decrease in the
 solubility of oxygen in  the sodium carbonate solution at higher
 temperatures.  Or perhaps  it may  be caused by a thermally in-
 duced change  in the structure of  coal itself.  Alternatively,
 there may  be  a change  in the reaction mechanism or kinetics,
 possibly caused by the thermal decomposition of a reactive
 intermediate.
                       CONCLUSIONS
     It has been  demonstrated with a small autoclave reactor
 that leaching  of  high-sulfur bituminous coals with hot, dilute
 solutions  of  sodium carbonate containing dissolved oxygen under
pressure can remove most of the inorganic  sulfur and a portion
of  the organic sulfur.  Dilute alkaline leach solutions have
been shown  to be more effective than neutral or acidic solutions.
More concentrated alkaline  solutions are less beneficial and
even detrimental,  causing  lower reduction  in sulfur and decreas-
ing the heating value recovery.   The desulfurization reaction
becomes independent of the stirring rate at high stirring speeds.
                              1060

-------
     Leaching longer than 1-1.5 hr.  results  only in a modest
increase in sulfur removal,  but the  advantage is offset by a de-
crease in heating value recovery.   Increasing the oxygen partial
pressure improves the extraction of  sulfur without a noticeable
decrease in the heating value recovery.  The improvement is due
mainly to an increase in the removal of organic sulfur, amount-
ing to 30% in some cases.  An optimum temperature range has been
observed at about 120-150°C for which the reduction of sulfur
is maximum.  At higher temperatures, both the extraction of sul-
fur and the heating value recovery decline significantly.
    The overall Ames oxydesulfurization process has been shown to
be effective in removing almost all of the inorganic  sulfur and
a significant portion of the organic sulfur  under  relatively
mild  conditions.  The moderate  temperatures  and pressures  do
not require  extraordinary equipment, and  the alkaline conditions
                    i'
provide a  non-corrosive  environment.   With proper  regeneration
of  the leaching  solution, the  process  should prove an econom-
ical  method  for  the chemical cleaning  of  high-sulfur coal.
                      ACKNOWLEDGEMENT
      This work was supported by the U.  S.  Department of Energy,
 Division of Fossil Energy,  and the Iowa Coal Project.
      The statistical analysis, performed by Dr. Craig Van
 Nostrand, is gratefully acknowledged.
                               1061

-------
                         REFERENCES

 Agarwal,  J.  C.,  Giberti,  R.  A.,  Inninger,  P.  F.,  Petrovic, L. F.,
      and  S.  S.  Sareen.   1975.   Chemical  desulfurization of coal
      Mining  Congr.  J.  61(3),  40-3.

 Agarwal,  J.  C.,  Giberti,  R.  A.,  and L. J.  Petrovic.   1976.
      Method  for removal  of  sulfur from coal.  U.  S. Patent
      3,960,513.

 Chen, M.-C.   1978.   Desulfurization of coal-derived pyrite
      using solutions containing  dissolved  oxygen.  M. S. Thesis.
      Iowa State University.

 Friedman, S., LaCount, R. B.,  and R. P.  Warzinski.  1977.
      Oxidative  desulfurization of coal.  In T. D. Wheelock, ed.,
      Coal desulfurization:  chemical and  physical methods.  ACS
      Symposium  Series  64, Am.  Chem. Soc.,  Washington, D. C.

 Friedman, S., and R. P. Warzinski.  1977.  Chemical cleaning
      of coal.   Trans. ASME  99(3), 361-4.

 Kosikov,  E.  M.,  Kakovskii,  I.  A., and E. A. Vershinin.  1973.
      Use  of  polarographic probes for measuring the concen-
      tration of  dissolved oxygen.  Obogashchenie Rud  18(4),
      39-41.      •

 Meyers, R. A.   1977.  Coal desulfurization.  Marcel Dekker,
      Inc., New York.

 Sareen, S. S.   1977.  Sulfur removal from  coals: ammonia/
      oxygen  system.  In T. D.  Wheelock,  ed., Coal desulfuri-
      zation:  chemical and physical methods.  ACS Symposium
      Series  64,  Am.  Chem. Soc., Washington, D. C.

 Tai,  C. Y.,  Graves,  G. V., and T. D. Wheelock.  1977.  Desulfu-
      rizing  coal with solutions containing dissolved oxygen.
      In T. D. Wheelock, ed., Coal desulfurization: chemical
      and  physical methods.  ACS Symposium  Series 64,  Am. Chem.
      Soc., Washington, D. C.

Wheelock,  T.  D., ed. 1977.  Coal desulfurization: chemical
     and physical methods.  ACS Symposium  Series 64,  Am. Chem.
      Soc., Washington, D. C.

Wheelock,  T.  D.  ca.  1978.  Chemical cleaning.   In Leonard,  J.W.
     et al.,  eds., Coal preparation.  4th ed.   Am. Inst. of
     Mining,  Metallurgical and Petroleum Engineers,  Inc.

Wheelock,  T.  D., Greer, R. T., Markuszewski, R.,  and R.  W.
     Fisher.   1978.  Advanced  development of fine coal desulfu-
     rization and recovery technology.   Annual Technical Prog-
     ress Report, Oct.  1, 1976 - Sept.  30,  1977,  IS-4363,
     Ames Laboratory DOE - Fossil Energy, Iowa State University,
     Ames, IA.


                               1062

-------
CONVERSION TABLE TO INTERNATIONAL (SI) SYSTEM UNITS

                1 Btu  =  1,055 joules
                1 Ib.  =  453.6 g
                1 Btu/lb. = 2.324 joules/g
                1 psi  -  6.89 kPa
                1 r.p.m. = 0.105 rad/sec
                        1063

-------
                   THE POTENTIAL FOR CHEMICAL COAL CLEANING:
                     RESERVES,  TECHNOLOGY,  AND ECONOMICS

              R.  A. Glberti ,  R. S.  Opalanko2, and J.  R.  Sinek1

                          Kennecott  Copper  Corporation
                           Lexington, Massachusetts
                         2
                          Resource Engineering,  Inc.
                           Lexington, Massachusetts


                                  ABSTRACT


      Based  on statistical data  on U.S. bituminous coal reserves published by
 the  U.S. Bureau  of Mines,  an estimate is presented on the tonnage of coal,
 by coal-producing  region,  which can potentially be made  to conform to the
 New  Source  Performance  Standard (NSPS) of 1.2 Ib S0_ per million Btu by
 chemically  removing 90-95  percent of the pyritic sulfur  and 0-40 percent of
 the  organic sulfur.

      The additional tonnage of  conforming  coal potentially obtainable by
 blending chemically cleaned coal with raw coal is estimated.

      The impact of  other criteria presently under discussion (0.2 Ib SO  per
 million Btu;  removal of 80-90 percent of the  original sulfur) is presenied
 on the tonnage of  coal potentially made conforming by chemical cleaning.

      The state of  the art of chemical cleaning is summarized.  Kennecottfs
 laboratory data on  the removal of pyritic and organic sulfur are discussed,
 and comparisons are made between:  oxygen-water versus oxygen-ammonia leaching;
 low-temperature (130°C) versus high-temperature (175-200°C)  leaching.

      Technical data resulting from these comparisons are used to project capital
 and operating costs for grass-roots  chemical coal cleaning plants.   The ecbn-
 omics of chemical coal cleaning are  compared against the purchase of low-sulfur
washed coal or the installation of  scrubbers.
                                      1064

-------
Introduction
     Chemical coal cleaning  studies were begun in 1971 by
Kennecott Copper Corporation in an  attempt  to develop low
sulfur coals from its  Peabody Coal  Company  divisionfs reserves.
Analyses reported in 1974 (Agarwal  et  al.,-1974) showed
significant economic,  energy conservation,  and environmental
advantages associated with chemical coal cleaning when compared
with other coal conversion/desulfurization  alternatives.   An
active coal desulfurization program was pursued by  Kennecott
until May 1975, when all coal research and  development  for
Peabody Coal was terminated, because  at  that time  the Supreme
Court upheld the Federal Trade Commission  ruling  ordering
Kennecott to divest itself of Peabody Coal.  At  termination,
the development program had progressed to  a stage at which
batch testing was close to completion, and the main emphasis
was on planning an internally funded pilot  plant  program.
Results of the batch simulation of the leach reactors have
mostly been reported in the literature by  Sareen et al.  (1975),
and by Sareen  (1977).  In addition to leaching,  every other
major unit operation on the flowsheet had been batch-tested:
 separation and washing  of clean coal  from  the leach reactor
 effluent, solution neutralization  and separatioa of the
 gypsum thus formed,  evaluation of  materials of cpnstruction,
etc.  A  detailed  process  design had shown  that only conventional
equipment would be  required  for a  commercial plant, thus  elim-
 inating  the need  to develop  new equipment  for which there is

                                1065

-------
 no reliable scale-up experience.
      The process is covered by  U.S.  patent  3,960,513  (Agarwal,
 Giberti, Petrovic,  June  1976) assigned  to Kennecott.
      Since 1975 there have  been,  and will continue  to  be,
 changes in the laws regulating  the.sulfur content in coal,  and
 in the economics of coal  desulfurization/conversion processes.
 Kennecott has  continued to  update the economics of  its chemical
 coal  cleaning  process, and  to identify  the reserves where it
 can be economically applied.
      This paper will  briefly summarize  the experimental results
 with  particular emphasis  on comparing some process  alternatives*
 in addition, it will  present recent reserve estimates, and pro-
 vide  updated economics.

 General  Considerations of Chemical Coal Cleaning
      The  removal of sulfur from coals by chemical leaching de-
pends on  the conversion of the various  forms of sulfur to soluble
species.  Chemical leaching has  two  significant advantages over
physical coal cleaning:
      1.  Fine,  dispersed pyrite  is removed  from coals
         without excessive grinding.
      2.  Organic sulfur may  be removed  as well  as pyrite.
     Because sulfur  exists in coal in three  general  forms, the
separation of each form requires different chemistry:
     1.  Pyritic sulfur must be  oxidized, either to  sulfur
         or, preferably,  to  soluble sulfate.  A variety of

                              1066

-------
         oxidants,  including air,  tonnage  oxygen,  chlorine,
         etc., can  achieve this.
     2.  Organic sulfur can be extracted by hydrogenation;
         part o£ the organic sulfur can also be  converted to
         soluble sulfur species by oxidation.
     3.  Sulfates are generally soluble in aqueous solutions,
         hence do not require chemistry other  than leaching.

Experimental Results
     It is virtually impossible to make a  sound  technical and
economic comparison of the various chemical leaching processes
from published data, because the processes have  been tested
by different investigators with various coals  and under varying
conditions.  This paper compares three oxygen  leaching alter-
natives tested by Kennecott:
     Low-temperature (s!30°C)  coal/water  slurry
     Low-temperature (si30 C)  coal/aqueous ammonia slurry
     High-temperature (>130°C) coal/water  slurry
     Data have been previously reported for the  low-temperature
02/H20 system (Sareen et al., 1975) and for the  low-temperature
02/NH3 system (Sareen, 1977).  Data on the high-temperature
C^/H-jO have not been reported heretofore.
     Figure 1 shows the removal of pyritic sulfur from coal.
At the identical temperature (130°C),  the  rate of pyrite leach-
ing for the 02/NH3  alternative is  slightly lower than that  for
07/H~0.  It should  be noted that no tests  were run for short
 &  L
reaction times to establish the kinetics  for  the high tempera-

                             1067

-------
O
UJ
UJ
O


E

t
                         J	I
20
                         O  02/H20, < 130°C, 300 psi O2

                         A  02/H20, 175°C. 200 psi O2~

                             02/NH3, 130°C. 300 psi O2



                             _J	L_	t      I     >
                   40    60    80   100   120   140


                           REACTION TIME. MINUTES
160   180   200
           Figure 1.  Pyrlte Removal for Various Oxydesulfurization Conditions
                                  1068

-------
ture (175°C)  02/H20  case.   It  should also be noted that the
high temperature Oj/f^O  tests  were run at 200 psi 02 partial
pressure rather than 300 psi,  and that the rate of pyrite  leach-
ing has been reported (Sareen  et al., 1975) to vary directly
with the square root of  the 02 partial pressure.
     The data for the 02/NHj system  are  reported  as a  band for
the five ammonia molarities tested  (0.5, 1.04, 1.94,  2.95, S.O)
to simplify the comparison. All data were obtained with. Illinois
#6 coal.
     Figure 2 shows  the  previously  reported  data  for  organic
sulfur removal for the low temperature  02/H20 and 02/NH3 systems.
Also shown are previously unreported data demonstrating the
removal of organic sulfur at higher temperatures  (175°C) in
the 02/H20 system.  Organic sulfur removal at the higher tem-
perature is comparable to that in the 02/NH3 system.   However,
as  shown in Figure 3, this is achieved at the expense of greater
Btu losses.  Figure  3 also shows the 02/NHj system to have
greater Btu losses than the 02/H20 system at the same tempera-
ture  C130°C).
     Data  on the  other process parameters, such as oxygen up-
take by coal,  extent  of coal  converted  to C02, CO, and hydro-
carbons, can mostly  be  found  in the cited papers.
     These data for  Illinois  #6 coal demonstrate the  effect
 of leaching chemistry on  the  removal of pyrite and organic
 sulfur and the yield of heating value.   Previously reported
 data indicate  that  comparable pyrite leaching behavior can be
 expected for other  coal types. However, considerably different
                              1069

-------
     40
Q
tu

|

UJ
cc
CO

o


<
u
cc
o
     30
     20
o
                       O O2/H2O, 130°C, 300 psi 02


                       A O2/H2O, 175°C, 200 psi O2

                          02/NH3, 130°C, 300 psi 02
            20    40
                        60    80  " 100   120   140


                         REACTION  TIME, MINUTES
                                                             180   200
      Figure 2.   Organic Sulfur  Removal  for Various OxydMuIfurfzstion Conditions
                                 1070

-------
2

CO
a*
20

18

16

14

12

10

 8

 6

 4

 2

 0
                        J	L
                                                      ...
                                           ^0.5 - 5.0M NH3\
                                              "
       0    20    40    60    80   100   120   140   160   180

                                  REACTION TIME, MINUTES
        O O2/H2O, 130°C, 300 psi O2
        A O2/H20, 175°C. 200 psi O2
        ^ 02/NH3. 130°C, 300 psi O2

J	I	I	I	L     »      I     I
                                                             200   220   240  260
                  Figure 3.  Btu Losses for Various Oxydesulfurization Conditions
                                       1071

-------
organic sulfur removal and Btu yield should be  anticipated
with different coal types.   Accordingly,  the selection  of the
optimum leaching chemistry will depend on the amount  of sulfur
which must be removed from the coal, and  on the organic sulfur
removal and Btu losses for the specific coal.
     We now need to project the performance that  this process,
when fully developed, is likely to achieve in a commercial
plant.  Performance will vary according to coal type  and to
the processing conditions chosen.   However, there are enough
data to pinpoint the most likely range of desulfurization,
bracketed by three cases:
     Case          % pyritic S removal       % organic S removal
     90/0                   90                          0
     90/20                  90                         20
     95/40                  95                         40
Table 1 describes our best estimate of Btu yield  and  weight
yield for these three leaching alternatives, as well  as for the
coarse wash which always precedes leaching.

Process Description
     Based on the data just described, a  commercial process
flowsheet can be developed as follows.
     Run of mine coal is first given a coarse coal wash.
     Since chemical coal cleaning will generally  produce a
leached coal with a lower sulfur content  than the standards
that must be met, some of the washed coal will  by-pass  the
                             1072

-------
Slurry liquid
Temperature, C
Sulfur removal, %
pyritic
organic
Leach Btu yield,*
Leach weight yield,?
Wash Btu yield,!
Wash weight yield,*
water
130

90
0
92
98
90
85
aq. NH3
130

90
20
89
98
90
85
water
175-200

95
40
86
98
90
85
Table 1. Assumptions for
various leaching conditions.
         1073

-------
chemical cleaning plant  as  shown in Figure 4.
     A simplified flowsheet of  the chemical cleaning module  of
Figure 4 is shown in Figure 5.  The process description has  beeii
reported earlier (Irrainger  and  Petrovic, 1974; Agarwal et  al.,
1974; Sareen et al., 1975)  but, for clarity, will be repeated here
briefly, assuming the low-temperature 02/H20 process is used.
     The portion of the  coal to be chemically cleaned is
crushed to -1/8" in an impact mill and  then ball milled to
-100 mesh in a water slurry.
     The slurry is diluted  to 20%  solids  and preheated to  130°C
in Karbate heat exchangers  and  pumped  into the  reactors.   For
an 8,000 TPD plant, the  reactors  are acid brick lined pressure
vessels, 33 in number, 9 ft diameter by 84 ft long,  divided
into 11 compartments furnished  with  agitators,  and provide the
coal with a residence time  of 2 hrs.   Vessels of this  type
and dimension are presently in  use at  hydrometallurgical plants
in several countries.
     An oxygen plant supplies oxygen at 300  psi pressure.   The
discharge slurry is cooled by passing it back through the heat
exchangers.  The clean coal is  separated from the liquid phase
in a  thickener  and  a rotary filter,  where it is washed clean.
It is  then balled on pelletizing disks and dried.
      The overflow from  the  cleaned coal thickener is neutralized
with lime  or  limestone.  The resulting gypsum sludge is thickened,
filtered,  and discarded.   The  neutralized liquor is recycled
for  use as  process  water in the desulfurization reactors.
                                1074

-------
o
«4
Ol
                         COARSE
                         WASH
                                                           CHEMICAL
                                                           CLEANING
CLEAN
COAL
                                        Figure 4.  Overall Coal Cleaning Process

-------
                                                                  OXYGEN PLANT
 WASHED
 COAL

1 SHIFT/DAY       HAMMER
7 HOURS/SHIFT
1700 HOURS/YR
240 DAYS/YR
GYP$UM TO
TA1UNOS POND
                              STORAGE    RECYCLE
                                      lUME
                           THICKENERffNEUTBALIZATION
                                                                                               NITROGEN
                                                                                                 REACTORS
   MAKE-UP WATER
                                                                         AGGLOMERATION , ,.»
COAL TO
POWER PLANT
                                SLURRY
                                 PUMP
                               Figure 5.  Rowiheet for Oj/HjO Leaching of Pyritte Sulfur

-------
 Process  Capital and Operating Costs
      The capital and operating costs shown in Tables 2 and 3
 are based on a commercial process as described.  For some
 coals it may be desirable to perform the leaching at higher
 temperatures or in aqueous ammonia to enhance organic sulfur
 removal, as discussed; the costs for these process alterna-
 tives have not been calculated in detail, but are believed
 to be of the same order.
     The capital cost for processing 8,000 TPD of coal totals
 $123 million in mid-1977 dollars, equivalent to $46.3/annual
 ton of coal feed.   This estimate is based on a green-field
 plant, and includes all the required off-sites as well as con-
 tingency.
          i
     The operating cost, in Table 3,  amounts to $23.5/ton
 clean coal,  based on utility financing.   Using this  method of
 financing, an average annual capital  charge of 15.91 results
 from depreciation,  interest on debt,  return on equity, taxes,
 and insurance.
     This is the maximum cost of chemical coal cleaning,  i.e.
 the cost when no portion of the coal  can by-pass the chemical
 leaching section.   Figure 6 shows the cost of clean  coal as a
 function of the percent of the coarse-washed coal that can
by-pass  the chemical cleaning section so that the blend will
 still meet the desired standard.   These  costs range  from
 $S.65/ton of product from coarse cleaning alone to $23.S/ton
 of product for chemical cleaning alone.

                               1077

-------
                                           Million  $

        Coal Handling and Washing              6.0
        Crushing                               8.4
        Reactors                              19.7
        Oxygen Plant (1,000 TPD)               22.4
        Liquid/Solid Separation               11.1
        Neutralization                         8.1
        Agglomeration                         14.3

        Depreciable Investment                90.0

        Land
        Working Capital
        Startup Costs
        Interest during Construction

        Total Investment                     123.4

        $/Annual Ton Leached -  46.3

Assumptions:
    Mid 1977 dollars
    Offsites and contingency factored into each process area
    8,000 TPD coal feed to leaching
               Table 2. Capital cost estimate for
               Kennecott Oxygen Leaching process.
                              1078

-------
                                                 Million S/yr1
                   7
     Process Losses                                   9.7
     Chemicals

            Lime                                      3.3
            Flocculant                                0.5
            Binder                                    5.3
     Utilities

            Steam                                     3.9
            Electricity                               7.9
     Labor, Supervision


     Direct Costs


     Average Capital Charge  (15.9%  total  capital)

     Maintenance, Labor $ Supplies

     Plant Overhead (20% of labor §  utilities)
     Administrative Overhead (10% of labor)
     Total Operating Cost                            61.4
            mill/KWH5 = 9.54
            $/ton coal product =  23.5
1.   Mid 1977 dollars;  regulated utility  financing
2.   17.2% overall Btu loss,  including 10%  Btu loss  in
    conventional coal cleaning.   Cost figured at $18/ton ROM coal,
3.   Includes depreciation,  interest  on debt,  return on equity,
    insurance,  and taxes
4.   9% of depreciable capital,  excluding contingency
5.   8,000 TPD plant produces 2.61 MM TPY product
    containing 12,000 BTU/lb
               Table 3.  Operating cost estimate
               for Kennecott Oxygen Leaching process
                              1079

-------
    25
    20
a
LU
o

a
o
cc
a.
O
u


1
15
10
                  I
                   I
I
I
I
f
     Coarse

     Wash
       10    20    30   40    50    60    70    80



           % OF PRODUCED COAL CHEMICALLY CLEANED




                   Figure 6. Cost of Coal Cleaning
J	

90   100


   Chemical

   Cleaning
                                 inso

-------
Definition of Compliance Coal
     For the purpose of this  study it  is  necessary  to  define
the standard to which the coal must be desulfurized in order
to be considered a suitable product of chemical cleaning.
     There is considerable controversy at this time with
regard to New Source Performance Standards  for fossil-fired
power plants.  The selection  of standards for this  analysis
is difficult and subject to possible criticism.  Nevertheless,
two levels of emissions were  chosen and the technique  can be
applied for any standards that are ultimately promulgated.
The selected levels are 1.2#S02/MMBtu, the  present  New Source
Performance Standard and a level required of some existing
plants, and 2.7#S02/MMBtu, a  more liberal standard  for exist-
ing plants.

Estimate of Production and Reserves of Coal Available  to
Chemical Coal Cleaning
     Based on coal seam data  on pyritic sulfur content, organic
sulfur content, and calorific value, reported by Cavallaro,
Johnston, and Deurbrouck (1976) and by Wizzard  (1978), pro-
jections have been made of the production and reserves which
can meet our postulated standards of 1.2, respectively 2.7,
Ib S02 per million Btu by chemical coal cleaning, but  not by
coal washing alone.  All three process variants,  90/0, 90/20,
and 95/40, were used in these projections.
     Table 4 shows the results in terms of the  annual  tonnage
of low-sulfur coal thus produced.  It  shows that  a  10-281
                            1081

-------
o
oo
ro
Region
1975 Production Ii
(MM net ton)
icremental Clean Coal Production, MM
Raw Washed
a) Clean coal specification: 1.2 Ib {
Northern Appalachian
Southern Appalachian
Alabama
Eastern Midwest
Western Midwest
Western
"Other"
TOTAL
t of U.S. Production
1B2
192
23
142
10
85
15
650
100
7 12
67 25
7 0
1 1
0 5
60 11
_-
140 54
22 8
b) Clean coal specification: 2.7 Ib J
Northern Appalachian
Southern Appalachian
Alabama
Eastern Midwest
Western Midwest
Western
"Other"
TOTAL
t of U.S. Production
182
192
23
142
10
85
15
650
100
46 36
173 16
17 1
4 8
1 1
30 -4
* * mm
321 66
49 10
net t/yr
Chemically Desulfurized
90/0
90/20
>02/MM Btu
26 37
29
7
4
1
0
--
67
So
54
10
7
1
0
--
109
17
502/MM Btu
59 68
0
4
43
2
•0
• »
108
17
0
4
62
3
•0
* *'
137
21
95/40
70
77
12
19
2
0
180
28
74
0
4
91
5
0
--
174
27
Cleaning
Cost
($/t)
17-20
10
20
19-22
16-20
...

16-17
...
11-12
17-18
18-20
...
...


                                            Table 4. Incremental clean coal production:

                                            Raw, washed and chemically desulfurized.

-------
 increase, in U.S. coal production meeting a 1.2#SO~/MMBtu
                                                 A
 standard can potentially be achieved by chemically cleaning
 coal.  The bulk of this production is from Appalachian coals.
 For the 2.7#S02/MMBtu standard a 17-27% increase is projected
 with most of the increase coming from Northern Appalachia
 and Eastern Midwest.
     Note that the cleaning costs in Table 4 are competitive
 with recently announced purchase prices for low-sulfur coal.
     Table 5 shows the results in terms of potential reserves
 of low-sulfur coals created by the advent of chemical cleaning.
 (To make this projection it was necessary to assume that the
 coal seam data not only characterize U.S. production, but also
 U.S. reserves.)
     To illustrate with an example how these data were derived,
 Figure 7 shows the case for coal from the Southern Appalachian
 region complying with a standard of 1.2#S02/MMBtu.  The dis-
 tribution curves for raw coal and washed coal  are taken from
 the cited literature.  Because these data indicate that up
 to 50% of all coal from this region complies with the standard
 if washed,  only that portion of each curve is  shown which
 refers to the non-complying coal.  The distribution curves for
 leached coal are calculated from the raw coal  data according
 to the procedure described below, and are shown for the three
process alternatives:  90/0, 90/20, and 95/40.
     It can be shown from Figure 7 that if, say, the 90/0
alternative is used,  this will make available  an additional 181

                              1083

-------
o
CD
Region
Reserves In
(billion t) R
cremental Clean
aw Washed
a) Clean coal specification:
Northern Appalachian
Southern Appalachian
Alabama
Eastern Midwest
Western Midwest
If es tern
TOTAL
t of U.S. Reserves

Northern Appalachian
Southern Appalachian
Alabama
Eastern Midwest
Western Midwest
Western
TOTAL
t of U.S. Reserves
68
SS
2
89
16
22
230
100
b) Clean coal
68
35
2
89
16
22
230
100
3 5
12 5
1 0
1 1
0 8
15 5
32 24
14 10
specification:
17 13
32 3
1 0
3 5
1 1
21 1
75 23
33 10
Coal Reserves, Billions Tons
Chemically Desulfurized
90/0 1 90/20
1.2 Ib S02/MM Btu •
10 14
5 10
1 1
2 4
2 2
0 0
20 31
9 13
2.7 Ib S02/(M Btu
22 25
0 0
0 0
27 39
3 5
0 0
52 69
23 30
95/40

26
14
1
12
3
0
56
24

28
0
0
57
8
0
93
40
                  * Assumes sulfur distribution in reserves is the sa»e as  in 1975 production
                                      Table S. Incremental clean coal reserves:
                                      Raw, washed, and chemically desulfurized.*

-------
                                          SOUTHERN APPALACHIAN REGION
o
00
      GO
O
c/j
oo
3.5


3.0


2.5


2.0


1.5

1.2
1.0


0,5
                     I      I      \     I	I     I   I   I   i  I   I   I	I
                                                                                       1
                                                                                          J
             0.01   0.1    0.5     2    5  10    20 30 40 50 60 70 80    90  95      99
                                                                                      99.9   99.99
               Figure 7.  Coals in Southern Appalachian  Region Capable of Meeting  1.2# SO/MM Btu
                                             Standard  after Various Treatments

-------
  of all Southern Appalachian coal.
       It also shows that the compliance blend of washed coal
  and 90/0 leached coal averages 75% washed coal and 25% leach-
  ed coal for the entire region.  This value can be verified
 by integrating both curves.

 Sample Calculation
      The  results in Table  4 were generated from raw coal sulfur
 analyses  CCavallaro et al., 1976 and Wizzard,  1978)  presented
 as means  and standard deviations (a)  for  each  coal-producing
 region.   Using  the Southern Appalachian region as  an example,
 the raw coal data  are:
     Pyritic Sulfur    Organic  Sulfur      Total Sulfur
       Mean     a          Mean     o         Mean     a
       0.46   0.72        0.62    0.22       1.08    0.88
 The small amount of sulfate  sulfur in the  coal was  added to the
 pyritic sulfur  so  that
     Pyritic S  + Organic S  • Total S
     For any three  variables x, y, and z related by
     x + y = z
 it can be shown that:
     1)  x + y = z
           2     ?     9   2z(x.y.)
     2)  cz2 = ox2 + ay2 *     N1/:L   - 2Cx)Cy)
where xi = individual values of x
   •  x » mean of x.
     a  «  standard deviation of x.
      *             .             i
     N *  number of samples
                              1086

-------
     Furthermore,  if a variable w  is defined by
     w. = kx.
where
     k is a constant,
then
     w = kx
     °w = kax
     Using the above relations,  and assuming given percentages
of pyritic and organic sulfur removal,  one  can  find the jaean
and the standard deviation of total sulfur  in desulfurized
coal.  For pyritic/organic removals of  90/0, 90/20, and 95/40,
the Southern Appalachian region  can be  calculated to yield:
                        90/0           90/20            95/40
                  'Mean      o     Mean     a      Mean      a
Total Sulfur       Q>666   0.273   0.542   0.230   0.395   0.158
in Cleaned Coal
     The calorific value of the  chemically  cleaned coal is
estimated using the weight yields  and  Btu yields shown in Table 1,
Again, for Southern Appalachian  coal,  these produce calorific
values of:
              Raw Coal      90/0       90/20      95/40
  Btu/lb       13,314      13,234     12,803     12,371
     Therefore, the SO, emissions from Southern Appalachian  coal
will be:
                      90/0           90/20           95/40
                Mean      a     Mean     a     Mean    a
 Ib S02/MMBtu    1.006   0.412   0.846   0.359    0.638  0.255
                               1087

-------
      These three distributions  are plotted  in Figure  7  and
 indicate the following  incremental amount of raw coal available
 to chemical leaching, over  and  above  the 50% that would comply
 by washing only:
                              90/0      90/20     95/40
   % of Non-Washable  Coals
   Meeting Standard              18       34        49
       The average blend of washed and leached coal, obtained
 by integration of the distribution curves over the region,  is:
                              90/0      90/20     95/40
   Clean  Coal  Blend
   (washed: leached)            75:25     73:27     ™:24
     These blend projections are conservative.   Lower overall
 costs  could be achieved by using more washed-only coal  for
 blending, but this would lower the tonnage of coal available
 from the  region.
     For  1975, total production from the Southern Appalachian
 region was 192 million tons (Keystone, 1977).   Assuming  this
 tonnage to be typical, and assuming a 90/0 sulfur removal,  raw
 coal suitable as feed to chemical coal cleaning plants is
 (192) (0.18) • 35 million tons  per year in this  region.  The
 clean coal thus produced will  be somewhat less,  due to losses
 in washing and leaching, and is  calculated as follows:
     (192) (0.18)  [(0.75)(0.85)+(0.25)(0.83)(0.92)|  - 29 million  TPY
Explanation:
      0.75 = fraction of blend which  is  coarse-washed only
      0.85 = weight  yield after  coarse wash  (Table 1)
      0.25 = fraction of blend which  is  washed  and leached

                              1088

-------
     0.83 = weight yield after washing  (851 yield)  and
            leaching (98% yield)
     0.92 = adjustment for 81  parasitic  consumption of
            clean coal for power  and steam consumed in
            leach plant.
     The cleaning cost of $10/ton,  shown in Table  4, was
derived from Figure 6 for a 75:25 blend.

Chemical Coal Cleaning vs. Stack  Gas Scrubbing:
Performance Comparison
     As shown in the preceding projections, large  tonnages
of high-sulfur coal can be made to  conform to  stringent sulfur
emission standards by chemical cleaning.  These  results can
generally also be achieved by  stack gas  scrubbing,  and the
final decision must therefore  be  based  on economics, which will
be discussed in the next section.
     On the other hand, scrubbing is reported  as able to remove
in excess of 85% of the sulfur dioxide  in the  flue gas.  Chemical
coal cleaning, on the other hand, removes varying  fractions of
sulfur, depending on the coal  and on the leaching  variant, but
seldom removes much more than  70% of the sulfur.  This would
pose a problem in new plants requiring  85% sulfur  removal.
Chemical Coal Cleaning vs.  Stack Gas.Scrubbing:   Economic
Comparison
      Sulfur dioxide scrubbers must be sized for the full power
                               1089

-------
plant generating capacity.   Because  the fixed charges  must be
distributed over the actual  kWh  generated, the cost  of scrubbing
in mills per kWh is  high for plants  with  low load  factors.
Coal cleaning,  on the other  hand,  is decoupled from  boiler
operation, and  the cost  of coal  cleaning  in mills  per  kWh is
independent of  load  factor.
     Figure 8 shows  a cost comparison between chemical coal
cleaning and stack gas scrubbing.  The coal cleaning costs
are the figures derived  in the preceding  calculations.  The
scrubbing costs are  escalated from a Tennessee Valley  Authority
report (McGlamery et al., 1975), and are  based on  wet  lime
and \*et limestone scrubbing  because  they  account for 70% of
currently installed or planned  scrubbing  capacity.  Both
scrubbing costs and coal cleaning  costs are expressed in mid-
1977 dollars and assume  regulated  utility financing, i.e.,
15.9% of capital cost charged to annual operating  cost.  Neither
cost includes particulates  collection.
     Chemical coal cleaning  costs, as well as scrubbing costs,
contain site-specific cost  components which cannot be  reflected
with precision  in a generalized  comparison such  as Figure 8.
Coal cleaning costs  depend  significantly  on local  environmental
standards and on the quality of  the  coal. Scrubbing costs vary
greatly with site-specific  factors,  as reflected in  the high
variance of actual plant cost experience. Nevertheless, Figure 8
shows that within the most  common  load factor range, coal clean-
ing costs should clearly be  comparable to scrubbing  costs.
                              1090

-------
                           S  »:
                           g

                           §  ?:


                              "
                                                 1. W.t Unman* SO, Sowbbinfl
                                                   1000 MW
                                                   Euy Ritrofil
                                                   No Pmculin RMmmi

                                                 2. Wn Urn* SO. Soubt-ng
                                                   200 MW
                                                   Mo&na flttrofit Difficulty
                                                   No Pirriculn* Rwravil
                                    //x/ / //v / / / / / /T7"\£:
                                        J   J   .4    J   .1   .7

                                          renM PIANT tCAO fACTOH
   a

   a


1  "
ii


11


14


II


10


 I


 I
                  1. Wn Urnmon* SO, Scnjbbin,
                    1000 MW
                    E«y Ritreflt
                    No Pimculra Rimenl
                  2. Wit Urn* SO, Smibbing
                    200 MW
                    Mo
-------
 (Approximately 74% o£ all 1976 U.S. coal-fired utility capacity
 fell within the 35-65% load factor range; approximately 56% of
 U.S. capacity fell within the 40-60% load factor range.)  Figure
 9 shows that the capital costs of chemical coal cleaning is
 comparable to that of scrubbers.

 Conclusions
 1.  Chemical coal cleaning has the potential of constituting,
    in many cases, an economically viable alternative  to stack
    gas scrubbing and to the purchase of low-sulfur  coal.
 2.  Assuming a clean coal specification in the range of 1.2-2.7
    Ib S02 per million Btu,  chemical coal cleaning has the
    potential of increasing  the production of compliance coal
    by 180 million tons  per  year.   Reserves of compliance coal
    would be increased by 60-90 billion tons.
3.  Chemical coal cleaning has potential application chiefly
    in Eastern coal states and in the .Eastern Midwest..
4.  Effective coal cleaning  requires not only the removal of
    pyrite but also the  removal of at least 20% of the organic
    sulfur in the coal.
5.  Chemical coal desulfurization has a high probability of
    technical feasibility because it can be implemented entirely
    in state-of-the-art  industrial equipment,  and is similar
    in many respects  to  existing  hydrometallurgical  process
    plants.
                             1092

-------
to
cc
2
2

I
I
•3
80 i-


75


70


65


60


55


50


45


40


35


30


15
i
O   20
     15


     10


      5
       1. Wet Limestone  SO, Scrubbing
         1000 MW
         Easy  Retrofit
         No Particulate Removal
       2.  Wet Lime SO, Scrubbing  - $109.8/kW
          200 MW
          Moderate  Retrofit  Difficulty
          No Particulate Removal
                            I      I
                                          J	L
                                  .4     .5     .6

                                 LOAD  FACTOR
                                                .7
Blend of Coals
Washed : Leached
                                                                            25%: 75%
                                                                            75%: 25%
 1.0
         Figure  9.  Capital Cost of SO2  Scrubbing and Chemical Coal Cleaning
                                        1093

-------
                          Referenes
 Agarwal,  J.C.,  R.A. Giberti, and L.J. Petrovic. June 1,  1976.
      Method for sulfur from coal, U.S. Patent 3, 960, 513.

 Agarwal,  J.C.,  R.A. Giberti, P.P. Irminger, L.J. Petrovic,
      and  S.S. Sareen. April 1974. Coal desulfuriztion:
      costs/processes and recommendations, paper presented
      at the 167th ACS National Meeting, Division of Fuel
      Chemistry,  Los Angeles, California.

 Cavallaro,  J.A., M.T. Johnston, and A.W. Deurbrouck. 1976.
      Sulfur reduction potential of the coals of the United
      States; a  revision of report of investigations 7633,
      RI 8118, U.S. Bureau of Mines.

 Hamilton, P.A.,  D.H. White, and T.K. Matson.  1975. The
      reserve case of U.S. coals by sulfur content:  2. The
      western states.  1C 8693, U.S. Bureau of Mines.

 Irminger, P.P.,  and L.J. Petrovic.  June 1974.  Design con-
      siderations and status of some coal conversion pilot
      plants, paper presented at the 77th AIChE National
      Meeting.

 McGlamery,  G.G., R.L. Torstrick, W.J. Broadfoot, J.P. Simpson,
      L.J. Henson, S.V.  Tomlinson, and J.F. Young. January 1975.
      Detailed cost estimates for advanced effluent desulfuriza-
      tion processes, report for Office of Research and Develop-
     ment,  U.S.  EPA, EPA-600/2-75-006.

 Sareen, S..S.  March 1977.  Sulfur removal from coals:  Ammonia/
     oxygen system, paper presented at the 173rd National ACS
     Meeting, New Orleans,  Louisiana.

Sareen, S.S., R.A.  Giberti, P.P.  Irminger, and L.J. Petrovic.
     September 1975.  The use of oxygen/water .for removal of
     sulfur from coals,  paper presented at the 80th AIChE
     National Meeting,  Boston,  Massachusetts.

Thompson,  R.D.,  and H.F.  York.   1975.  The reserve base of
     U.S.  coals  by sulfur content:   1.  The eastern states.
     1C 8680, U.S.  Bureau of Mines.

Wizzard,  J.   August 1978.   Personal  communication.   Pittsburgh
     Energy Technology  Center,  Department of Energy.

1977 Keystone coal  industry manual.   1977.  McGraw-Hill Inc.
                              1094

-------
to convert from
Btu
kWh
pounds
tons (short)
tons (metric)
minutes
hours
days
to (SI units)
joule
joule
kilogram
kilogram
kilogram
seconds
seconds
seconds
multiply by
1,055.87
3.60 x 106
0.4536
907.18
1,000.00
60.00
3,600.00
86,400.00
Table 6:  Conversion factors*
              1095

-------
                    JPL COAL DESULFURIZATION PROCESS BY
                       LOW TEMPERATURE CHLORINOLYSIS

                    John J.  Kalvinskas and George C.  Hsu
                     California Institute of Technology
                            Pasadena, California
                                  ABSTRACT
     The Jet Propulsion Laboratory of the California Institute of Technology
has conducted an extensive laboratory scale investigation under a U.S.  Bureau
of Mines contract of 12 coals including bituminous, sub-bituminous and  lignite
coals for desulfurization by a three-stage process that includes chlorination,
hydrolysis and dechlorination.  Results are represented for organic,  pyritic,
and total sulfur removal.  A parametric study of operating conditions was
conducted.  A unique feature of the process is that high organic sulfur removal
is demonstrated in conjunction with high-pyritic sulfur removal for total
sulfur removal under favorable operating conditions of greater than 70  percent.
Preliminary costing of the desulfurization process indicates competitive costs
relative to other coal desulfurization processes and flue gas desulfurization.
Further development work on the process is continuing under U.S. Department of
Energy auspices.  The future development activity includes a bench-scale
continuous flow mini-pilot plant operation at 2 kilograms coal feed per hour
and a bench-scale batch operation at 2 kilograms of coal per batch.  A
preliminary equipment design is presented for the continuous flow mini-plant
coal desulfurization operation.
                                      1096

-------
                              INTRODUCTION









      The Jet Propulsion Laboratory (JPL)  of the California Institute




of Technology has investigated the use of chlorination for the oxidation




of both pyritic and organic sulfur contained in bituminous coals for




accomplishing coal desulfurization to meet Environmental Protection




Agency stack emission standards of 1.2 pounds SO  per million thermal




B.t.u.'s.  For coals with a heating value of 12,000 B.t.u. per pound




acceptance standards translate to 0.7 weight percent sulfur in the coal.




     The early research activity was carried out by JPL under internal




funding to devise the basic elements of the process.  Preliminary findings




indicated that coal desulfurization on Illinois No. 6 bituminous coal




having a total sulfur content of 4.77% sulfur with approximately equal




distribution of organic and pyritic sulfur demonstrated approximately  70%




organic sulfur reduction, up to 90% pyritic sulfur reduction and 76% total




sulfur reduction  (Hsu, et al., 1977).  The laboratory scale research




reported here and under sponsorship of the U.S. Bureau of Mines represents




additional data obtained on 12 high sulfur coals including 9 bituminous,




2 sub-bituminous, and 1 lignite coals, Table 1.  The coals have been




treated under the conditions of chlorination, hydrolysis and dechlorina-




tion constituting the JPL coal desulfurization process.  The research




work is continuing under the U.S. Department of Energy sponsorship.  The




follow-on activity will include bench-scale, batch tests at 2 kg of coal




per batch and construction and operation of an integrated continuous flow,




mini-pilot plant to demonstrate the process at a coal feed rate of 2 kg/hr.
                                  1097

-------
                                                                       Ash
o
VO
oc
Number
108
219
190
276
026
342
240A1
097
086
213
PHS-398
(BOM)*
PHS-513
(BOM)*
Seam, County & State
Pittsburgh, Washington, Pennsylvania
Kentucky #4, Hopkins, Kentucky
Illinois, #6, Knox, Illinois
Ohio #8, Harrison, Ohio
Illinois #6, Saline, Illinois
Clarion, Jefferson, Pennsylvania
Big 0, Lewis, Washington
Seam 80, Carbon, Wyoming
Zap, Mercer, N. Dakota
Kentucky #9
Raw Head, 3A, Upper Freeport Seam,
Somerset, Pennsylvania
Mine 513, Upper Clarion, Butler,
Pennsylvania
Rank (Wt.%)
HVA (Bit.) 9.50
HVA (Bit.) 8.06
HVA (Bit.) 8.49
HVA (Bit.)11.19
HVC (Bit.) 10. 84
HVA (Bit.) 9.19
Sub-bit B 29.40
Sub-bit A 9.80
Lignite 11.49
HVB (Bit.) 9.36
19.7
Organic
1.07
1.08
1.90
2.24
2.08
1.39
1.75
0.84
0.63
1.86
0.46
Pyritic
2.06
1.40
1.05
2.07
4.23
5.01
- 1.60
0.38
0.56
1.89
2.26
1.76 <0.2
(Physically cleaned,
high organic coal)
Total
3.13
2.56
3.05
5.15
6.66
6.55
3.36
1.23
1.22
3.32
3.01
1.76
          Samples received from Dr. Scott R. Taylor, Department of Energy, Pittsburgh,  Pennsylvania.
                                   Table 1.  Selected Coals for Chlorinolysis Experiments
                                             Under Bureau of Mines-Sponsored Program

-------
                    LABORATORY SCALE PROCESS STUDIES








     The laboratory coal processing for coal desulfurization by the JPL




low temperature chlorinolysis process is depicted in Figure 1.








Apparatus



     Laboratory apparatus for chlorination of the coal is depicted in




Figure 2.  Laboratory apparatus for hydrolysis of chlorinated coal is




depicted in Figure 3.  Dechlorination apparatus for the chlorinated and




hydrolyzed coal is depicted in Figure 4.








Laboratory Data




     Laboratory data on the coal desulfurization process is summarized in




Table 2 for coal PSOC-219 (HVA Bit, Ky #4, Hopkins, Ky) and in Table 3




for 11 other eastern, midwestern and western coals.  A total of 9 bituminous,




2 sub-bituminous and 1 lignite coals has been tested that represents a total




sulfur content in the raw coal from 1.22 to 6.66 weight percent.  Organic




sulfur content ranges from 0.46 to 2.24 weight percent and pyritic sulfur




from <0.2 to 5.01 weight percent.  Sulfate sulfur constitutes the remaining




sulfur in the coal samples and averaged less than 0.2 weight percent for 9




coals, 0.29 to 0.35 weight percent for 2 coals and  0.84 weight percent for




1 coal.




     Coal samples were analyzed by Galbraith Laboratories, Knoxville,




Tennessee for sulfur composition and chlorine in both  the  raw and treated




coal samples.  Ultimate analyses were conducted on  several treated coal




samples.  Water wash, water scrubber solutions and  gas samples were  also




analyzed for given tests to obtain material balances.
                                  1099

-------
 POWDERED COAL
 (-100 TO+200 MESH)
 WATER
 (30-70% OF COAL)
 ORGANIC SOLVENT
 (e.g., METHYL CHLOROFORM)
       SOLVENT
       RECOVERY/
       RECYCLE
     CHLORINOLYSIS*

     50 • 100°C, 1 atm
      < 1 TO 2 HOURS
    STIRRED REACTOR
                      SOLVENT
                      REFLUX
WASTE WATER
INCLUDING HCI, H2SO4
AND OTHER WATER
SOLUBLE SULFATES **
AND CHLORIDES
           HCI (g) -*-
           H20 (g)
                                                            CHLORINE GAS
                                                         •*• HCI
             CHLORINATED
             COAL SLURRY
HYDROLYSISVEVAPORATION
                                    50- 100°C
                                < 2 HOURS, 1 atm
                                STIRRED REACTOR
                               • WATER
                                        COAL SLURRY
       FILTRATION
WATER
(FOR DISPLACEMENT
WASH)
                                        COAL (FILTER CAKE)
    OECHLORINATION *

       350 - 550°C
        STEAM
     5 min. TO 60 min.
  ROTARY DRYER, 2 rpm
                                                           STEAM
                               DESULFURIZEDCOAL
                               (WITH <0.1% CHLORINE)
LABORATORY GLASSWARE EQUIPMENT FOR THESE
PROCESSES IS SHOWN IN FIGURES 2, 3 AND 4.
             Figure 1.   Process flow diagram for laboratory
                        scale coal  desulfurization
                                1100

-------
                                                                                       WATER OR
                                                                                       SODIUM
                                                                                       HYDROXIDE
                                                                                       SOLUTION
                                                                                              WATER
                                                                                             GAS
                                                                                             HOLDER
                                                                                              TITRATION
                                                                                          SLURRY
                                                                                          SAMPLING
                                                                                          LINE
CHLORINE
TANK
                                                                 SLURRY OF
                                                                 POWDERED MOIST
                                                                 COAL IN
                                                                 METHYL CHLOROFORM
CONSTANX
TEMPERATURE
BATH
                                Figure  2.   Laboratory glassware  apparatus
                                             for chlorination of coal

-------
o
10
THERMOCOUPLE
         TEMPERATURE
         CONTKOUER

                                                            REFLUX
                                                            CONDENSER
                                                                                                     WATER
                                                                                                     SCRUBBER
                                                                    HYDROLYZER
                                                                    nooo mi)
                                                                    SIURRY OF
                                                                    CHLORINATED
                                                                    COAL AND
                                                                    WATER
                                                                    HEATING
                                                                    MANTLE
                    FIGURE  3.  LABORATORY GLASSWARE APPARATUS FOR
                                   HYDROLYSIS OF CHLORINATED COAL

-------
                                       QUARTZ TUBE
    _^J
                                                        DECHLORINATION
                                                        REACTOR

, 	 , \
[T \_
' 	 MOTOR AND
CHAIN DRIVE
ROTOR (1 RPM)
ii / i
SPLIT TUBE /
FURNACES
              WATER
                                                                          ICE
                                                                          BATH
\^
                                                                                                  WATER
                                                                                                  GAS
                                                                                                  COLLECTOR
STEAM
GENERATOR
                    Figure 4.   Laboratory equipment for  dechIon'nation of  coal

-------
CHLORINATION: 500 ml stirred flask; 100 gram sample of -100 to +200 mesh coal; atm pressure;
74°C, Cl2(g) at 0.75 g/min; methyl chloroform/coal at 2- water/coal at 0.5.
HYDROLYSIS: 1000 ml stirred flash; 60-100°C: water/coal at 2-4 per wash; 5-60 minutes
per wash; filtration water wash/coal at 1-2; 1 to ; washes.
DECHLORINATION : 1-inch diameter quartz rotary tube at 1-2 RPM in split tube furnace; coal at
2 to 4 grams/batch; steam atm. an 0.4 to 110 grams/hour; temp of 350 to
550°C; 15 to 75 minutes.
Ave
No . of
Runs
RAW COAL
1
1
6
9
Chlorination
Time
(Hin.)
10
20
30
60
120
Residual Sulfur Analysis
(Wt. %)
Organic
Pyritic
Sulfate
Total
Sulfur Removal
tt)
Organic
Pyritic
Total
Dechlorination
Residual Cl (wt . 7.)
Before
After
COAL PSOC-219, HVA BIT. KY . NO. 4, HOPKINS, KY .
1.08
0. 78
0.69
0.82
0.59
0.45
1.40
0.79
0.73
0.41
0.31
0.48
0.08
0.04
0.11
0.07
0.05
0.14
2.56
1.61
1.50
1. 39
0.95
1.07
28
36
27
45
58
44
48
71
78
65
37
41
46
63
58
4.8
4.9
5.4
10.4
14.6
0.12
0. 37
0.42
0.36
WATER/ COAL - 0.3
1
T
30
60
120
0.57
0.56
0.70
0.75
0.40
0.28
0.04
0.06
0.06
1.37
1.00
1.04
47
48
45
46
71
79
46
61
. 	 59
4.74
8.86
18.9
0.95
0.21
0.26
WATER/COAL -0.7
•,
T
?
30
60
120
0. 78
0.63
0. 71
0.45
0.47
0.41
0.01
0.02 •
O.Q3
1.24
1.15
1.14
28
41
34
68
66
71
51
55
55
5.1
9.2
11.4
TEMP. - 50 °C
2
0
0
30
60
120
0.78
0.69
0.54

1
1
1
30
60
120
0.71
0.72
0.74

1
60

1
120
0.65

0.30
0.35
0.13
0.25
0.02
0.01
0.05
1.15
0.83
0.84
28
36
50
75
91
82
55
67
67
18,6
0.17
0. 53
1.16

0.45
0, 52
0.50
TEMP. -60°C
0. 16
0.18
0.08
0.01
0.07
0.03
0,87
0.96
0.74
34
40
46
59
87
94
66
62
71
8.6
22.3
0.47
0.50
TEMP. - 85°C
0.35
0.12
1.12
40
75
56
11.3
0.86
Cl2(g) - 0.375 g/min
0.63
0.38
1.31
72
55 ] 49
11.3
0.31
Cl2(g) - 1.5C g/min
2
1
1
30
60
120

1
o
2

1
1
1
3
1

1
1
1
30
60
120

15
20
30
60
120
0.48
0. 33
Q..70

0.72
0. 74
0.64

0.99
0. 77
0.66
0.55
0.66
0.56
0.19
0.04
0,25
0.40
0.18
1.30
0.9fc
0.92
56
69
35
60
86
97
49
62
64
6.3
13.1
19.8
0.57
1.00
SOLVENT - CARBON TETRACHLORIDE
0.31
0.43
0.50
• 0.01
0.08
0.05
1.03
1.20
1.19
33
37
40
78
69
64
60
53
53
8.8
9.0
0.21
0.15
0.96
SOLVENT - TETRACHLOROETHYLEME AT 74°C
0. 34
0.30
0.57
0.53
0.46
0.02
0.13
0.07
0.05
0.05
1.35
1.20
1.30
1.13
1.18
8
29
39
49
37
76
79
59
62
67
47
53
49
56
54
24, 4
11 ,2
15.3
17,1
1.29
1 , 14
0.41
1.01
0.64
SOLVENT - TETRACHLOROIiTHYLENE AT 10P°i:
15
30
60
0.66
1,00
0.73
0,77
0.14
0.42
0.01
•0,01
0,05
1.44
1.14
1.21
39
7
32
45
90
70
44
56
53
23.1
0 ,44
0.31
0. 39
                   TABLE 2
      Laboratory Coal  Desulfurization  Daca
Chlorination  Reaction  Parameters.  Coal  PSOC-219
               1104

-------
CHLORINATION: 500 ml stirred flask; 100 gram sample of -100 to +200 mesh coal; atm.
pressure; 74°C; Cl2
-------
Ave
No. of
Runs
Chlorination
Time
(Min.)
Residual Sulfur Analysis
(Wt. •/„)
Organic
Pyritit
Sulfate
local
Sulfur Removal
Organic
Pyricic
Total
Dechlorination
Residual Cl (Wt . 7.)
Before
After
PSOC-213, HVB BITUMINOUS, KY, NO. 9 (CL2(g) - 0.187 g/min.)
RAW COAL


120 •
1.86
0.53
1.89
1.65
0.07
0.01
3.82
2.19
-
72
-
13
-
43 .
0.05
4.6

0.57
PSOC-276, HVA BITUMINOl'S, OHIO NO. 8, HARRISON, OHIO
KAW COAL
1
3
60
120
2.24
0. 74
0.99
2.07
0.40
0.17
0.84
0.20
0.24
5.15
1.35
1.39

67
56

81
94

74
73

10.7
16.6

0.54
0.22
PSOC-026, HVC BITUMINOUS, ILL NO. 6, SALINE, ILL.
.-tAW COAL
: i 30
faO
2.08
1.30
1.25
4.23
0.89
0.55
0.35
0.02
0.06
6.66
2.21
1.87

38
40

79
87

67
72

-
8.46

0.20
0.42
WESTERN COALS
PSOC-086, LIGNITE, ZAP, MERCER, NORTH DAKOTA
SAW COAL
i . 30
1 60
'
0.63
0.35
0. 32
0.52
0.23
0.35
0.03
0.17
0.06
1.22
0.75
0.73

44
50

59
37

39
39
0.00
-
8.00

0.33
-
PSOC-097, SUB- BITUMINOUS A, SEAM 80, CARBOX, WYOMING
KAW COAL
1
1
1

30
60
120
0.84
0. 70
0. 74
0. 79
0.38
0.31
0.05
0.19
0.01 '
0.05
0.02
£.06
1.22
1.06
0.81
1.05

17
12
5

18
87
50

14
31
15

-
-
-

0.28
0.13
0.22
PSOC-240, SUB-BITUMINOUS B, BIG D, LEWIS, WA .
KAW COAL
1

123
1.75
0.49
1.60
0.68
0.01
0.05
3.36
1.22

72

58

64
0.02
-

0.26
           TABLE 3 (Cont'd)
Laboratory Coal  Desulfurization  Data
 Eastern,  Midwestern,  Western  Coals
               1106

-------
Chlorination




     Chlorination was carried out by bubbling chlorine at injection rates




of 0.187 to 1.5 grams per minute through a slurry of 100 grams of -100 to




+ 200 mesh coals with 200 grams of solvent (methyl chloroform, carbon




tetrachloride, tetrachloroethylene) and 20-70 grams of water contained in



a 500 ml. stirred flask equipped with a reflux condenser, cold trap and gas




holder, Figure 2.  The Chlorination was conducted at 50-100°C, atmospheric




pressure and reaction times of 10, 20, 30, 60, and 120 minutes.




     Observations indicated that chlorine injection rates of 0.187 grams




per minutes were probably too low for obtaining maximum reaction rates.




Chlorine injection at 1.5 grams per minute was excessive with chlorine




being carried over from the coal slurry into the cold trap.  At injection




rates of 0.75 grams per minute, the injected chlorine was readily absorbed




by the coal slurry with no penetration of the slurry surface until an




apparent saturation limit for chlorine was reached at approximately 45




minutes.  At this point, chlorine carryover into the vapor phase and cold



trap suddenly becomes significant.




     Sulfur analyses are reported for organic, pyritic, sulfate and total




sulfur as obtained from Galbraith Laboratories.  The attendant processing




conditions for coal PSOC-219 are summarized in Table 2 for each product coal




analyses.  For the coal PSOC-219 Chlorination data represented, retention




time, chlorine injection rate, temperature, water content and solvent were




variables with coal mesh size, and the solvent-to-coal ratio was kept invariant




as noted in Table 2.  Principal observations were that extended Chlorination




times above 60 minutes did not result generally in increased desulfurization.
                                   1107

-------
Also, lower temperatures of 50 and 60°C and increased water/coal ratios




of 0.7 resulted in decreased organic sulfur removal.  Pyritic sulfur




reduction may be favored by the lower temperatures of 50 to 60 C and




reduced by the water to coal ratio of 0.7.  The other 11 high sulfur




eastern, midwestern and western coals were chlorinated with only retention




time as a variable (30, 60, 120 minutes) and chlorine injection rate




(0.75 gram/min.),temperature (74°C), solvent (methyl chloroform), solvent/




coal (2), water/coal (0.5) and mesh size  (-100 to +200) kept invariant.
Hydrolysis




     Hydrolysis conditions were at water/coal ratios of 2, 3 and 4, with




1 and 2 washes and including a water/coal displacement wash of 1 and 2




in the 2 filtration steps for a total water/coal consumption between 4




and 10.  Water temperatures were at 60°C, 80°C and 100°C as noted, Table 2.




Hydrolysis times were generally 60 to 120 minutes and as low as 5-20




minutes for given tests.  Tests with PSOC-219 indicated that a single




water/coal wash at 2 at a wash time of 20 minutes and water temperature of




80°C reduced the sulfate concentration in the treated coal to less than 0.1




weight percent.








Dechlorination




     Dechlorination conditions were at temperatures of 350 to 550 C in the




presence of a steam atmosphere.  Initial steam rates were high at 75-110




grams/hour with treated coal charged at 2-4 grams per batch.  Reduction




of steam values to 0.4 gram per hour have indicated no apparent reduction
                                    1108

-------
in the rate of HCl evolution in the dechlorination.   At 450 C,  the




dechlorinatior\ appeared to be complete in under 20 minutes, Figure 5.




The chlorine levels before dechlorination of the treated coal ranged




from 4.6 to 24 weight percent and after dechlorination ranged from




<0.01 to 1.29 weight percent.








                  COAL DESULFURIZATION CHARACTERIZATION









Twelve Eastern, Midwestern, Western Coals




     A summary of organic, pyritic and total sulfur removal for 4 bituminous




eastern coals, 5 bituminous midwestern coals, and 2 sub-bituminous and 1 lignite




western coals is presented in  Tables  2 and  3  (Kalvinskas,  et. al. 1977).  The




data is representative of  coal chlorination at a Cl2(g) feed rate of 0.75




gram/min -100 grams coal for 60 minutes.  No specific correlations for sulfur




removal exist with geographical region.  Seven of the twelve coals show organic




sulfur removal greater  than  45 percent with a peak removal of  72  percent.




Two  coals  show no  or  little  organic sulfur  removal.   Nine  of the  twelve




coals show pyritic sulfur  removal  between 58  and  92 percent.   Total sulfur




removals are  between  34 and  74 percent  for  the  12 coals.   The  values




represent  averaged data.   Individual  runs and given  sample analyses indicate




peak removals at 83 percent organic sulfur, 99  percent pyritic sulfur and .83




percent  total sulfur.




      Total, organic  and pyritic  sulfur removals and residual sulfur




 concentrations after treatment by the desulfurization process  are plotted




 against  chlorination time for each of the twelve coals tested, Figures 6 to




 11.
                                   1109

-------
9.C
8.0
                               DECHLORINATION CONDITION
                               — TEMPERATURE, 45CTC
                               — STEAM RATE ,  75 GRAMS/HOUR
                               — COAL SAMPLE , 2-10 GRAMS
                                    TIME
                                      0
                                      5
                                      10
                                      20
                                      30
                                      50
                                      60
                                      HCI EVOLVED
                                       (GRAMS)

                                         0.0
                                         5.29
                                         6.66
                                         B.46
                                         8.49
                                      '   8.49
                                         8.49
                           2C     25    30    35     40
                           DECHLORINATION TIME (MINUTES*
                                                     45
55
6r
FIGURE 5.
                    STEAM DECHLORINATION OF TREATED
                    COAL WITH  TIME
                                  1110

-------
Total Sulfur




     Total sulfur removal and residual total sulfur is depicted with




chlorination  time for 12 coals in Figures 6 and 7, respectively.  Peak




removals and  minimum residual values are at 60 minutes chlorination time,




which exceed  sulfur removals at 30 and 120 minutes.









Organic Sulfur




     Organic  sulfur removals and residual organic sulfur for 12 coals is




depicted with chlorination time, Figures 8 to 9.  Residual organic sulfur




values are grouped relatively high for coals PSOC-190, 342, 026, and 513,




and represent an initially high organic sulfur in the raw coal that appears




somewhat resistant to chlorination.  Remaining coals have substantially




reduced levels of organic sulfur with treatment for 60 minutes.  Continual




chlorination  beyond 60 minutes to 120 minutes appears to increase organic




sulfur values in 4 of the coals/ and decrease organic sulfur in only




2 of the coals.









Pyritic Sulfur




     Pyritic sulfur reductions and residual values with chlorination time




are depicted, Figures 10 and 11, respectively.  Pyritic sulfur shows a sharp




reduction (44 to 48%, PSOC-219)  at short reaction times of 10 to 20 minutes.




Two of the coals, PSOC-219 and 097 have peak pyritic sulfur reduction of




78 and 87 percent at sixty minutes chlorination time and drop off to- 65




and 50 percent at 120 minutes respectively.  Four of the coals, PSOC-190,




276, 108, and 342,  provide increasing pyritic sulfur removals beyond 60 minutes
                                   1111

-------
                   CHLORINATION:
74"C; ATM. PRESS.; Cl
                                   METHYL CHLOROFORM^?OAL AT 2;
                                   WATER/COAL AT 0.5
                   HYDROLYSIS:
60-8
-------
6.8
6.4
                74°C; ATM. PRESS.; C\2M 0.75g/min;
                METHYL CHLOROFORM/COAL AT 2; WATER/COAL
                AT 0.5 '
                60-80°C; WATER/COAL AT 4/WASH; 60 min/WASH;
                FILTRATION WATER WASH/COAL AT 1; 1-2 WASHES
DECHLORINATION:  400-500°C; STEAM ATM; 30-60 min.
REF, TABLES J/2,_3 . COALS IDENTIFIED BY ERDA PSOC NUMBER.
                    CHLORINATION
 0.4  -
                                        60

                                    TIME (MINUTES)
      Figure   7,  Residual Total Sulfur with Chlorination Time
                   (Eastern,Midwestern, Western Coals).
                                   1113

-------
    80
    70
V~l
u
z
o
o
    60
0
t—
u
a   50
    40
    10
                  I

               CHLORINATION:
               HYDROLYSIS:
                                           I
                                                       I
                                74°C; ATM. PRESS.; CI2/a) 0.75 g/min;
                                METHYL CHLOROFORM/COAL AT 2; WATER/COAL
                                AT 0.5
                                60-80°C; WATER/COAL AT 4/WASH; 60 min/WASH;
                                FILTRATION WATER WASH/COAL AT 1; 1-2 WASHES
               DECHLORINATION: 400-500 C; STEAM ATM; 30-60 min.

               REF. TABLES -LI'*.. COALS IDENTIFIED BY ERDA PSOC NUMBER.
                                     TIME (MINUTESI
        Figure  8,  Organic Sulfur Reduction with Chlorination Time
                     (Eastern,  Midwestern,  Western  Coals).
                                        1114

-------
                CHLORINATION:
                HYDROLYSIS:
2.4
2.2
                 74°C; ATM.  PRESS.; Clo/glO.75 g/min;
                 METHYL CHLOROFORM/COAL AT 2; WATER/COAL
                 AT 0.5
                 60-80°C; WATER/COAL AT 4/V/ASH; 60 mtn/WASH;
                 OU™OV ^ff VT f^ I ti\/ ^*W^U ^ I t/ »» «JiT; uw riiiii/ wvr^ji i;
                 FILTRATION WATER WASH/COAL AT 1; 1-2 WASHES

DECHLORINATION:  400-500°C; STEAM ATM; 30-60 mln.
REF. TABLES Jf?,3... COALS IDENTIFIED BY ERDA PSOC NUMBER..
0.2 -
                20
            40
    60

TIME (MINUTES)
BO
100
                                                               120
      Figure   9,  Residual Organic Sulfur With Chlorination Time
                    (Eastern,  Midwestern, Western Coals).
                                     1115

-------
           CHLORINATION:
74"C; ATM. PRESS.; CI2 ra) °-75 9/min;
METHYL CHLOROFORM/COAL AT 2; WATER/COAL
AT 0.5
                          60-80 C; WATER/COAL AT 4/WASH; 60 min/WASH;
                          FILTRATION WATER WASH/COAL AT 1; 1-2 WASHES
           DECHLORINATION:  400-500"C; STEAM ATM; 30-60 m!n.
           REF. TABLES J »?»?... COALS IDENTIFIED BY ERDA PSOC NUMBER.
            20
                                   60

                              TIME (MINUTES)
                                                                      120
Figure  10,   Pyrytic  Sulfur Reduction With  Chlorination Time
                (Eastern, Midwestern,  Western Coal).
                                   1116

-------
              CHLORINATION:    74°C; ATM.  PRESS.; ClofM °-75 9/min''
5.2
4.8
0.4
              HYDROLYSIS:
METHYL CHLOROFORM/COAL AT 2; WATER/COAL
AT 0.5
60-80°C; WATER/COAL AT 4/WASH; 60 min/WASH;
FILTRATION WATER WASH/COAL AT 1; 1-2 WASHES
              DECHLORINATION:  400-500°C; STEAM ATM; 30-60 min.
              REF. TABLES_IA3_.COALS IDENTIFIED BY ERDA PSOC NUMBER.
                                         60
                                   TIME (MINUTES)
       Figure 11, Residual Pyritic Sulfur with Chlorination Time
                   (Eastern, Midwestern,  Western Coals).
                                    1117

-------
 and up to 120 minutes.  Analyses of  given  samples have  shown  up to  100% pyritic




 sulfur removal.   Residual pyritic  sulfur values  for PSOC-342  and  240 remain




 relatively high  compared to  the other  coals.   Other coals  have residual




 pyritic sulfur values of 0.1 to 0.4  weight percent.








                 PARAMETRIC DESULFURIZATION DATA, PSOC-219








      Thirty coal desulfurization test  runs were  conducted  with coal




 PSOC-219,  HVA Bituminous Ky.  No. 4,  Table  2.   Chlorination parameters




 investigated with respect to coal  desulfurization with  time are solvents




 (methyl  chloroform, carbon tetrachloride,  tetrachloroethylene), temperatures




 (50,  60,  74,  85  C), water/coal of  0.3, 0.5 and 0.7  and  chlorine feed rates




 of 0.187,  0.375,  0.75 and 1.5 grains  per minute per  100  grains of coal.




 Chlorination  parameters kept  invariant were:   coal size at -100 to  +200 mesh,




 solvent  to  coal  ratio at 2,  and atmospheric pressure.








 Solvents




     Pyritic  and organic sulfur removals with  solvents  methyl chloroform,




 carbon tetrachloride, and tetrachloroethylene  are depicted in Figures 12




 and 13 respectively.  The average pyritic  sulfur removal data provide some




distinct differences with respect to the three solvents for any given




Chlorination time.  However, the overall data patterns with Chlorination




time represented do not suggest consistent differences between the  three




solvents in providing either pyritic or organic sulfur  removal.
                                    1118

-------
                        COAL PSOC-219, HVA, bit., KY. NO. 4
                                        74°C, ATM. PRESS; C\2 la] 0.75 g/min;
                                        SOLVENT/COAL AT 2; WATER/COAL AT 0.5
CHLORI NATION:
                                        60-100°C; WATER/COAL AT 2-4/WASH; 5-60 min/
                                        WASH; FILTRATION WATER WASH/COAL AT
                                        1-2; 1-2 WASHES
                                        350-550°C; STEAM ATM: 15-75 min.
HYDROLYSIS:
DECHLORI NATION
REF. TABLE
       20 -
       10
                     20
        40
     60

TIME (MINUTES)
Figure 12,  Pyritic Sulfur Reduction,  Coal PSOC-Z19 with Chlorination Time
             (Parametric data with solvents - methyl chloroform, carbon
             tetr a chloride,  tetrachloroethylene).
                                        1119

-------
2
O
g

LU
Ct
Of.
u.
y

1
                                               CARBONTETRACHLOR1DE
    20 -
                      COAL PSOC-219, HVA, bit., KY. NO. 4
    10  -
                      DECHLORINATION
                      REF. TABLE _2_
                                       74°C, ATM. PRESS; Cl2 (q) 0.75 g/min;
                                       SOLVENT/COAL AT 2; WATER/COAL AT 0. 5
                                       60-100°C; WATER/COAL AT 2-4/WASH; 5-60 min/
                                       WASH; FILTRATION WATER WASH/COAL AT
                                       1-2; 1-2 WASHES
                                       350-550°C; STEAM ATM; 15-75 min.
                  20
                               40           60
                                       TIME (MINUTES)
80
100
120
  Figure 13,  Organic Sulfur Reduction,  Coal PSOC-219 with Chlorination Time
              (Parametric data with solvents - methyl chloroform,  carbon
              tetrachloride, tetrachloroethylene).
                                       1120

-------
 Temperature




      Pyritic and organic sulfur removal with chlorination time for




 chlorination temperatures of 50, 60, 74, and 85°C are depicted, Figures



 14 and 15, respectively.




      Pyritic sulfur removal appears aided by the temperatures of 50 and




 60 C relative to 74°C and 85°C.  Organic sulfur removal appears to be




 assisted by a temperature of 74°C relative to 50  and 60°C.








 Water/Coal
      Pyritic and organic sulfur removal with chlorination time is depicted




 for parameters of water/coal at 0.3,  0.5 and 0.7, Figures 16 and 17,



 respectively.




      Although  the overall patterns  of data for water/coal with respect




 to chlorination time  are not totally  consistent,  water/coal of 0.3 and




 0.5 appear  to  favor greater pyritic and organic sulfur removal relative to



 a  water/coal of 0.7.




                   i




 Chlorine Feed  Rates
     Desulfurization data at  low chlorine  feed  rates of  0.187  and 0.375




grams per minute per 100 grams of coal are available for comparision with




the higher feed rates of 0.75 'and 1.5 grains per minute per  100 grams of




coal at long reaction times of 120 minutes, Table 2.  There  appear to




be no significant differences in desulfurization data within the existing




data variance between the different chlorine feed rates.  At 30 and 60




minutes, there appears to be no advantage  in desulfurization by increasing




the chlorine feed rate from 0.75 to 1.5 grams/minutes -  100 grains coal.
                                  1121

-------
        90 -
    z
    o
    u.

    i/)
    
-------
                    COAL PSOC-219. HVA, bit., KY. NO. 4
                                     74°C, ATM. PRESS; C\2 (q) 0.75 g/min;
                                     SOLVENT/COAL AT 2; WATER/COAL AT 0.5
                                     60-100°Q WATER/COAL AT 2-4/WASH; 5-60 min/
                                     WASH; FILTRATION WATER WASH/COAL AT
                                     1-2;  1-2 WASHES
                                     350-550°C; STEAM ATM; 15-75 min.
CHLORI NATION
HYDROLYSIS
DECHLORINATION:
REF. TABLE  2
                                       60
                                  TIME (MINUTES)
Figure 15,  Organic Sulfur Reduction, Coal PSOC-219 with Chlorination Time
            (Parametric values of temperature  at 50,  60,  74,  85 C)
                                      1123

-------
 z
 o
 ae
 Of
 U
                       COAL PSOC-219,  HVA, bit., KY. NO. 4
                                       74-C, ATM. PRESS; C\2 la)0.75 g/min;
                                       SOLVENT/COAL AT 2; WATER/COAL AT 0.5

                                       60-100° Q WATER/COAL AT 2-4/WASH; 5-60 min/
                                       WASH; FILTRATION WATER WASH/COAL AT
                                       1-2; 1-2 WASHES

                                       350-550°C; STEAM ATM; 15-75 min.
HYDROLYSIS:
DECHLORINATION
REF. TABLE  2
                                            60

                                      TIME (MINUTES)

Figure 16, Pyritic Sulfur Reduction,  Coal PSOC-219 with Chlorination Time
             (Parametric values of water/coal at 0. 3, 0. 5,  0. 7).
                                       1124

-------
                                                             H-O/COAL-0.3
                        COAL PSOC-219, HVA, bit., KY. NO. 4
                                        74"C, ATM PRESS; C\2 (g) 0.75 g/min;
CHLORINATION:
                                        SOLVENT/COAL AT 2; WATER/COAL AT 0.5
                                        60-100°C; WATER/COAL AT 2-4/WASH;
                                        5-60 min/WASH; FILTRATION WATER WASH/
                                        COAL AT 1-2; 1-2 WASHES
                        DECHLORINATION:  350-550°C; STEAM ATM; 15-75 rmn.
HYDROLYSIS:
                                          60
                                    TIME (MINUTES)
Figure 17,  Organic Sulfur Reduction,. Coal PSOC-219 with Chlorination Time
            (Parametric values of water/coal at 0. 3, 0. 5,  0. 7)
                                     1125

-------
      A calculation of stoichdometrie chlorine requirements for

 conversion of organic sulfur to sulfonates is 3 moles Cl_ per mole of

 organic sulfur and conversion to sulfate requires 3.5 moles Cl? per mole of

 organic sulfur.   Chlorine requirements to convert pyritic sulfur to sulfate

 are 3.5 moles of Cl_  per mole of sulfur.   On the basis of 3.5 moles of

 chlorine per mole of  total sulfur less the sulfate sulfur, chlorine

 requirements are from a low of 9.2 grams  Cl_ per 100 grams of coal for

 PSOC-086 (1.19%  organic and pyritic sulfur)  to 19.2 grams Cl_ per 100

 grams of coal for PSOC-219 (2.48% organic and pyritic sulfur)  to a high

 of 49.5 grams of C12  per 100 grams of coal for PSOC-342 (6.4% organic and

 pyritic sulfur).   The efficiency of chlorine usage for sulfur oxidation

 to sulfate  for coal PSOC-219 appears to be as follows:
          Chlorination Time                     Chlorine  Usage Eff.
              (minutes)                                 (%)

                10                                     95
                20                                     54
                30                                     40
                60                                     26
               120                                     12

     Thus, the addition of surplus chlorine at  long Chlorination times at

0.75 g/min of C12 per 100 grams of coal makes relatively inefficient use of chlo-

rine.  A reduction in chlorine addition after a short  Chlorination period may be

desirable to conserve chlorine while still maintaining desulfurization rates.



Sulfate

     The Chlorination oxidizes the pyritic and organic sulfur to water

soluble sulfates.   Residual values of sulfate in the processed coal are

primarily an indication of the effectiveness of the water wash in the
                                  1126

-------
hydrolysis stage and the displacement water wash in the filtration.




Residual sulfate values for PSOC-219 are included in Table 2 and for




the other 11 coals tested in Table 3.  Sulfate values after washing




are generally under 0.1 weight percent and only occasionally at higher




values,up to 0.4 weight percent.




     Generally excessive water wash conditions to extract the sulfate from




the coal have been used.  Preliminary data indicate that a single water wash




at a water/coal of 2 in the hydrolysis stage at 80°C and 20 minutes followed




by a water/coal filtration wash at 2/1 is adequate to reduce the sulfate




content to less than 0.1 weight percent.









Residual Chlorine
     Chlorine values in the treated  coals before  dechlorination  range




between  4.8 and  23.1 weight percent, Tables  2  and 3.   The  lower  chlorine




values are for the shorter chlorination  times, 10 to  30 minutes, and the




highest  values are present at  higher times of  60  to 120 minutes.




     Dechlorination of the treated coal  at temperatures of 350 to 550  C




in  a steam atmosphere for 15 to 75 minutes provides residual chlorine




values from <0.01 to 1.29 weight percent with-average values of  less than




0.5 weight percent.




     The bulk of the residual  chlorine (95%)  appears  to be readily removed




at  even  low temperatures of  350°C,  low steam rates (steam to coal of 0.1)




and 20 minutes.   A number of dechlorination  tests have shown reduced




residual chlorine values of  less than  0.1 weight percent.




     Additional  dechlorination experiments are required to obtain consistent




dechlorination  to 0.1 weight percent chlorine.
                                     1127

-------
Ultimate Analyses




     Ultimate analyses of raw and treated coals PSOC-219 and PSOC-190




are given in Table 4.  Coal PSOC-219 exhibits a significant reduction




in hydrogen, approximately 2 weight percent, whereas PSOC-190 exhibits




less than 1 weight percent reduction in hydrogen.  The nitrogen content




in the PSOC-219 raw coal appears in error at 0.1 weight percent.  The carbon




content of PSOC-190 rises sharply after treatment, apparently as a. result




in part of the combined decrease (5.2 percent) of sulfur, oxygen and




hydrogen.







Trace Metal



     Trace metal analysis in raw/treated PSOC-219 and PHS-398 coals indicate




sharp reductions for titanium, phosphorous, arsenic, lead vanadium, lithium




and beryllium (Table 5).  Reductions are from 48 to 91 percent in treated




PSOC-219 coal.








Material Balance
     Material  balances were obtained for coal, methyl chloroform, chlorine




and sulfur.  Water solutions, cold traps and gas holders were sampled and




analyzed to obtain total material balances.  A material balance for run




118-9/9/77 on coal PSOC-219 is represented, Table 6.  Solvent and chlorine




balances are 98.6% and 94.1% respectively.  Improvements in seals and handling




should lead to a better recovery of solvent and chlorine.  Coal losses are more




substantial and reflect the fact that dechlorination was carried out with 2-4




gram samples.  Relatively small handling losses of the coal-in dechlorination




of several tenths of a gram reflect sizeable percentage losses.  Additionally,




dechlorination in the run was carried out at 500 C which also provided a




significant loss of volatile material.  Restriction of dechlorination
                                    1128

-------
10
VO
Component
C
H
N
S
Cl
Ash
0 (by difference)
Moisture
Heating Value (Btu/lb)
PSOC-219
(HVA Bit. KY No. 4)
Raw Coal
(Wt.%)
74.16
5.30
0.10
2.56
0.03
8.06
9.79
0.00
13,398
Treated Coal
Run 138-10/17/77
(Wt.%)
75.53
3.46
1.84
0.88
0.45
7.78
10.06
-
12,412
Run 138-10/17/77
(Wt.%)
74.83
2.38
1.65
1.02
0.75
7.40
11.97
-
12.780
Run 120-9/16/77
(Wt. %)
77.30
3.16
1.26
1.00
1.40
6.23
9.65
0.00
. -
PSOC-190
(HVA Bit. ILL. No. 6, Knox. III.)
Raw Coal
(Wt.%)
69.15
4.89
1.00
3.05
0.06
8.49
13.42
0.00
-
Treated Coal
Run 109-8/8/77
(Wt.%)
74.15
3.99
1.36
1.36
0.06
8.29
10.80
-
-
                                Table 4.  Ultimate analyses of treated coals  PSOC-219  and  PSOC-190

-------
(jj
o
Analyses
Titanium
Phosphorous
Arsenic
Lead
Vanadium
Lithium
Barium
Beryllium
Cadmium
Mercury
Selenium
PSOC-219"
Raw Coal
PPM
1086
131
73
46
46
<10
5
8
1
<1
<1
PSOC-219 Treated Coal
Run 107 - 7/27/77
DDU
rrWI
510
68/130
25
4
12
5
5
4
<1
<1
<1
Percent
Reduction (Wt. %)
53.0
48.1/0.8
65.8
91.3
81.0
~50.0
0.0
50.0



Run 120 -9/1 6/77
PPM
680
68
49
5
48
-
-
13
-
—
— •
Percent
Reduction (Wt. %)
37.4
48.1
32.3
89.1
0.0
-
-
0.0
-
-
—
PHS-398b
Raw Coal
PPM
1400
1040
85
0.5
<25
20
<10
5
-
<0.5
<1
PHS-398 Treated Coal
Run 140 -10/20/77
PPM
700
700
9
3
<25
21
92
4
—
<0.5
<1
Percent
Reduction (Wt. %)
50.0
32.7
89.4
-
~0.0
0.0

20.0
-
~0.0
-0.0
          "HVABit KyNo.4.

          bRaw Head. 3A. Freidens (Somenet), Pa. Received from  Dr. Scott R. Taylor, Bureau of Mines, Pittsburgh, Pa.




                             Table  5.  Trace metal  analyses of raw/treated PSOC-219 and  PHS-398

-------
u>
Process Unit
Chlorinator (Feed)
Chlorinator Cold Trap
Chlorinator Gas Scrubber
Chlorinator Gas Collector
Solvent Evaporator
Hydrolyzer

Dechlorinator Gas Scrubber
Dechlorinator Gas Collector
Product Coal Storage
Total Accounting
Unaccounted
Process Stream
Coal. C£, Solvent, S
CH3 cc£3. c£
Cf, SO4. TOC

CH3 CC£3
Cf. SO4. TOC,
Trace Metals
C£. SO4. TOC

Product Coal, C£. S

Coal
(Ind. Sulfur)
Grams
97.07

0.045C
0.0029

1.1C
1.125e
2.Wf
2.31
74.09
(87.86)d
83.30
13.77
Wt.%


0.046C
0.003

1.1C
1.16*
2.97C
2.38
76.33
(90J5&
85.81
14.19
Methyl
Chloroform
Grains
200
1.3


195.8





197.1
2.9
Wt.%

0.7


97.9





98.6
1.4
Chlorine
Grams
45
12.69


1.5
18.1b

9.72b

0.34
42.34
2.66
Wt.%

28.2


3.3
40.2b

21.6b

0.8
94.1
5.9
Sulfur
Grams
2.56



<0.01a
1.30a

0.44a

0.71
2.45
0.11
Wt.%





50.8a

17.2a

27.7
95.7
4.3
         3SO4 as Sulfur
         bChloride
         cCarbon
          Product Storage Including Unaccounted Coal
         eTrace Metals
                                   Table  6.   Material balance for run  138-10/7/77, coal PSOC-219

-------
 temperatures to 400°C will bring losses on PSOC-219 to less than 1 weight




 percent.  Losses of coal found prior to the dechlorination stage were




 ^1.1 percent.  The major handling loss and loss of volatile matter appeared




 to be in the dechlorination stage.





                             MINI-PILOT PLANT




      Parallel with laboratory and bench-scale coal desulfurization studies,




 a continuous flow mini-pilot plant will be constructed for an integrated




 equipment operation.   Coal will be fed at a nominal rate  of 2000 grams per




 hour from a pulverized coal feed hopper through chlorination,  hydrolysis and




 dechlorination stages.   The coal desulfurization mini-pilot plant is  repre-




 sented as an integrated equipment unit,  Figure 18.




      Major equipment  units include a ground coal hopper and blender,




 chlorinator, hydrolyzer,  rotary vacuum filter,  flash dryer,  dechlorinator and




 product coal storage  hopper.




      The chlorinator  and hydrolyzer will be  constructed of acid-resistant




 brick in lieu of more expensive metal  claddings.  An immersion testing program




 has  been conducted with  the assistance of Pennwalt  Corporation and Stebbins




 Engineering  and Manufacturing Co.  to choose  acceptable  brick and  mortar samples




 for  the  highly corrosive  and abrasive conditions  to be  found in the chlorinator



 and  hydrolyzer.




                                ECONOMICS




Capital Costs




     Preliminary cost estimates have been made  (JPL, 1976) for a  12,500  ton




per day coal processing plant, Table 7.  The capital costs for the coal




preparation and desulfurization plant are estimated at $23-46 million.  On  the




basis of capital costs provided  (L.E. Bostwick, 1977) a grass roots Kel-chlor




plant for conversion of HCL to Cl2is $62 million.  The total capital investment




is estimated at $84-108 million.
                                   1132

-------
                                                                                           GIOUND COAL MOPPt«
                                                                                           AND ILENOEI

                                                                                        2\ CONDENSH

                                                                                        3\ IEFIIIOUATED COLO TIAf

                                                                                           GAS COLLECTOK

                                                                                           CMLOdlNAIOH

                                                                                           HYMOLYZFH

                                                                                           SOLVENT STORAGE TANK

                                                                                           VACUUM FILTH

                                                                                           FLASH 0»VE«

                                                                                           OECHLOIINATOI

                                                                                           CLEAN COAL STOHAOE

                                                                                           HOT GAS/AIK MIXEI

                                                                                           NEUTtALIZINO COLUMN

                                                                                           DtCHLOHINATC* OFF-GAS VtNT

                                                                                           DCCHLOIINATOI STACK GAS
                                                                                           LINE

                                                                                           DISPEISION MILL

                                                                                           INSULATED STEAM LINE

                                                                                           IOTMY AIRLOCK



                                                                                           DIRECTION OF COAL FLOW
DRAWING NO. M5-800-*
NOTE: SCALE FOR ORIGINAL IS X ?l DRAWING SCALE I/'}?' • 1'
        Figure  IB.   JPL .coal  desulfurization  mini-pilot plant  --
                        side elevation
                                            1133

-------
I.     Capital Investment (12,500 Tons of Coal Per Day)
                                                                  $ 106
       Coal Handling, Preparation and Desulfurization             $23-46
       Kel-Chlor Plant (Grass Roots Basis)                        $62
       Total Capital Investment                                   $85-108


                                                                  ($/ton)«
II.    Operating Cost

       Utilities                                                   1.05
       Materials
            Chlorine (3.5 Moles Cl2/Mole Sulfur for PSOC-219,      3.26-6.71
            384 Ibs/ton of coal 9$17-35/ton of Cl.)
       HCL (5% makeup, 19.2 Ibs/ton of coal 9 3$/Ib.)              0.58
       Methyl Chloroform (Makeup at 0.5%, 20
-------
Operating Costs




     The largest portion of the operating costs are raw material costs.




Chlorine costs have been included on the basis of the stoichiometric amount




of Cl, required to oxidize the organic and pyritic sulfur contained in




PSOC-219 coal to sulfate.  The Cl_ requirement is 384 Ibs. per ton of




PSOC-219 coal.  A cost of $17 to $35/ton of C12 includes all operating




costs and capital charges.  The $17 per ton of Cl_ represents an early




published cost  (Van Dijk and Schreiner, 1973) based on a battery limits plant




and the $35 per ton of Cl_ represents a recent estimated cost for a grass




roots plant (Bostwick, 1977).  Methyl chloroform solvent costs are based on




a 0.5% process  loss.  The cost of methyl chloroform is estimated on the




basis of cost projections for large scale production.  A reduced solvent usage




requirement or  improved solvent recovery will have a significant impact in




cost reduction.  Capital and maintenance charges are called out only  for the




coal processing plant since Kel-Chlor charges have been included in the




chlorine cost.







Fixed Charges



     Capital  recovery of  the  coal processing plant has been  estimated on the




basis of  15 years  at 10%  interest charges.   Taxes  and  insurance  are  3% of  the




fixed capital investment.   Total  fixed charges  amount  to  $2.70-4.68 per ton




of  coal.







Waste Stream



     Earlier cost estimates have  assumed that sulfuric acid recovery as  a




by-product would -defray the waste  steam processing costs.  Until this is




substantiated, an additional charge of $0.92 per ton of coal has been included




 for waste treatment and sludge processing.  It's based on a sludge processing
                                     1135

-------
cost with no by-product recovery and is in line with sludge disposal




costs incurred in flue gas desulfurization (Jimeson and Maddocks  1976)









Overall Process Costs




     The  overall process costs for coal PSOC-219 are estimated at $13 34




to $19.05 per ton of coal feed.  Coals with higher or lower sulfur conte




will have & proportionately higher or lower processing cost based on the




chlorine requirement of 3.5 moles per mole of organic and pyritic sulfur




The chlorine cost amounts to $1.55-2.94 for each 1 weight percent of sulf




in the coal.  Any inefficiencies in the chlorine usage in the process will



be reflected in proportionately higher chlorine costs.








                         RESULTS AND CONCLUSIONS









     Coal desulfurization data for twelve eastern, midwestern and western




coals that include bituminous,sub-bituminous and lignite coals show




substantial organic and pyritic sulfur removal for the majority of coals




Table 8.  Five coals show greater than 50% organic sulfur removal, 5 coals




show better than 80% pyritic sulfur removal and 6 coals show better than




60% total sulfur removal.  No correlation appears between sulfur removal




and geographical origin of the coal.  The desulfurization process appears




applicable to a wide variety of coals. Optimization of the coal




desulfurization process operating conditions is expected to achieve




desulfurization levels required to meet environmental sulfur compliance




levels for a substantial number of coals.  Costs of the desulfurization




process are competitive with existing flue gas desulfurization processes and




other chemical coal cleaning processes for dasulfurization.
                                    1136

-------
                                               SULFUR REMOVAL  (%)

 COAL DESCRIPTION                     ORGANIC          PYRITIC         TOTAL


                              EASTERN COALS
 PSOC-108, HVA Bit.                     53                79              &Q
 Pittsburgh, Wash., PA.

 PSOC-342, HVA, Bit.                     3                63              50
 Clarion, Jefferson, PA.

 PHS-398, Raw Head, 3A                - 42                92              71
 Upper Preeport, Somerset, PA.
 (BOM-High Pyr., Low Org.)

 PHS-513, Mine 513,                     34                 _              34
 Upper Clarion, Butler, PA.
 (BOM-Phys.  Cleaned, High Org.)

                             MIDWESTERN COALS

 PSOC-219,  HVA Bit.                     45                78              63
 Ky #4,  Hopkins, Ky.

 PSOC-276, HVA Bit.                     67                81              74
 Ohio  #8,  Harrison, Ohio

 PSOC-026, HVC Bit.                     40                87              72
 111.  #6,  Saline,  111.

 PSOC-213, HVB Bit.                     72                13              43
 Ky. #9  (120 min.,  C12(0.182  g/min)

 PSOC-190, HVA Bit.                      19                90              4?
 111.  #6, Knox,  111.

                              WESTERN COALS

 PSOC-240A1, Sub-bit. B                  72                53             '54
 Big D, Lewis, Wash.  (120 Min.)

 PSOC-097, Sub-bit. A                    12                87               34
 Seam 80, Carbon, Wyo.

PSOC-086,Lignite                        50                 37              39
 Zap. Mercer, N. Dak.

 *(Chlorination  - 60 minutes,  C12 @ 0.75 g/min. - 100 grains)

              Table  8.   Summary of Coal  Desulfurlzation Data*
                        Eastern, Midwestern, Western Coals
                                   1137

-------
                                REFERENCES
Bostwick, L., Private communication. 1977.

Hsu, G., J. Kalvinskas, P. Ganguli, G. Gavalas. 1977. Coal desulfurization
     by low temperature chlorinolysis. ACS Symposium Series, No. 64, coal
     desulfurization.

Jet Propulsion Laboratory. 1976.  Coal desulfurization by low temperature
     chlorinolysis.  Proposal No. 76-763.

Jimeson, R., and R. Maddocks. 1976. Trade-offs in selecting SO  emission
     controls.   Chemical Engineering Progress.  72:8         X

Kalvinskas, J., et al. 1977.  Final report for phase 1 - coal desulfurization
     by low temperature chlorinolysis.  Jet Propulsion Laboratory Publication
     78-8.

Van Dijk,  C.,  and W.C. Schreiner.  1973.   Hydrogen chloride to chlorine via
     the Kel-chlor process.  Chemical Engineering Progress.  69:4.
                                   1138

-------
                            ACKNOWLEDGEMENT
     The research described in this paper was carried out at the




Jet Propulsion Laboratory, California Institute of Technology, and




was sponsored by the United States Bureau of Mines through an interagency




agreement,  Contract No. J0177103, with NASA.
                                   1139

-------
              Conversion factors  from English  units  to  the
                   International  System of Units  (ISU)
To convert from
English units

atmosphere

British thermal unit
(mean)

inch

pound (Ibm avoirdupois)

ton (short, 2000 pound)

ton (metric)
   to ISU
newton/meter

joule


meter

kilogram

kilogram

kilogram
   multiply by
1.01325   x 10"
1.05587   x 10'
2.54
x 10
              -2
4.5359237 x 10
9.0718474 x 10
              -1
1.00
x 10"
                                      1140

-------
           OXIDATIVE COAL DESULFURIZATION USING NITROGEN OXIDES
                               THE KVB PROCESS

                                 E. D. Guth
                                  KVB, Inc.
                             Tustin, California
                                  ABSTRACT
     The ecologically acceptable utilization of coal energy sources  is vital
to the nation's technological progress and economic well being.   Methods and
processes to control coal combustion emissions particularly sulfur oxides
are being evaluated to determine their relative merits.   KVB's coal  desul-
furization process offers a low cost means to remove pyritic and up  to 40
percent of the organic sulfur from coal.

     The KVB coal desulfurization process is based upon selective oxidation of
the sulfur constituents of the coal.  In this-process, dry coarsely  ground
coal (+28 mesh) is heated at one atmosphere pressure in the presence of
nitrogen oxide and oxygen gases for the removal of a portion of the  coal sulfur
as gaseous sulfur dioxide (S02>.  The remaining reacted sulfur in the coal is
in the form of inorganic sulfates, sulfites or is included in an organic
radical.  The non-gaseous sulfur compounds derived from pyrites are  removed
from the pretreated coal by subsequent washing with water.  Additional washing
with heated caustic solution followed by water removes up to 40 percent of the
organic sulfur.

     The active oxidizing agent is believed to be NO..  The process, however,
uses a gas mixture containing oxygen (0.5 to 20 percent 0? by volume), nitrogen
monoxide (0.25 to 10 percent NO by volume), nitrogen dioxide (0.25 to 10
percent N02 by volume) and nitrogen (N«) the remainder.

     The mechanism of oxidation is not known; however, it is postulated that
NO is oxidized by oxygen to N02 which is reduced back to NO in the reaction
to form oxidized sulfur compounds.

     The process is in its early stages of development.   Laboratory experi-
ments conducted on 50 gram samples in a batch reactor, with five different
coals, indicate that the process has desulfurization potential of up to 63
percent of sulfur with basic dry oxidation plus water washing treatment and
up to 89 percent with dry oxidation followed by water washing, caustic
treatment and final water washing.  However, depending on the amount of desul-
furization required, the extraction and washing steps may or may not be
                                     1141

-------
required.  Where dry oxidation only could remove sufficient  sulfur to meet
the sulfur dioxide emission standards, this  technology provides a very simple
and inexpensive system.
    The washing step removes iron and loosely bound inorganic material which
reduces the ash content of the coal.
    In the KVB process all the pyritlc sulfur is converted  to either sulfur
oxides or sulfates.
    Economic estimates indicate that coal could be desulfurized on a
commercial scale for $6.00 to $10.00/ton using KVB's process.
INTRODUCTION
     Chemical coal cleaning  is  the treatment of coal  with chemical
reactants  to produce a product  with improved more uniform fuel
properties.   The purpose of  chemical coal cleaning  is sulfur
removal.   Also minerals and  trace elements are removed in the
processing steps.  Precombustion desulfurization can  decrease
the need for flue gas scrubbers as well as reduce corrosion in
power generating units using coal as the fuel.  Off-line coal
desulfurization increases the reliability of power  unit operation
by reducing  boiler dependence on scrubber operation.   The decrease
in ash and trace elements has the added advantages  of decreased
mill wear,  less fuel and ash to transport and more  uniform combus-
tion properties.  In evaluating coal cleaning the overall power
plant fuel scenario should be examined considering  the advantage
of R.O.M.  and processed fuels.   Lower corrosion will  lead to lower
capital and  operating costs.  Ash and trace element contaminants
are removed  from the flue gas by physical methods  (e.g.,
precipitators).
                                 1142

-------
     KVB's chemical coal cleaning method is part of an overall
fuel cleaning technology.  Since 1973 KVB has developed fuel
cleaning technology to remove sulfur from oils and coal.  This
presentation is a report on the technical development of KVB's
coal desulfurization method.  Some aspects of the oil desulfuriza-
tion technology are discussed as they relate to the removal of
organic sulfur from coal.

     The selective oxidation of the sulfur compounds in coal is
the primary step of KVB's patented (U.S. 3,902,211) coal
desulfurization process.  The oxidation uses gas phase nitrogen
dioxide as a carrier for oxygen with nitrogen as a diluent and
removes sulfur in three ways (Figure 1):

        Gas Phase - oxidizing about one half of the pyritic
        sulfur to S02

        Water Phase - washing the oxidized pyritic sulfur
        from the coal as water soluble iron sulfites and
        sulfates

        Caustic Phase - treating the water washed coal with
        caustic to remove about one half of the organic
        sulfur as inorganic sulfites and sulfates

     The three sulfur removal steps can be employed singly or in
combination with or in conjunction with other methods for
physical removal of pyritic sulfur.
                               1143

-------
                         Coal
                      Oxidation
SO,
from Pyritic
Sulfur
  Water
   wash
SO,
from Organic
Sulfur
 Caustic
treatment
                     Clean Coal
            Figure 1.  Process description.
                                                      P-213
                        1144

-------
     The oxidation of organic sulfur compounds to sulfides and
sulfones using N02 and oxygen is reported in the patent litera-
ture.  The N02 oxidation can be carried out to oxidize the
sulfur atoms selectively.  Further, reactant N02 is regenerated
from the reduced form, NO, by reaction with gaseous oxygen at
ambient conditions.  KVB has applied N02 oxidation to the complex
mixtures of inorganic and organic chemical forms of sulfur in
oil and coal for sulfur removal.

     The high oxidation potential of N02 and its selectivity of
reaction to oxidize sulfur compounds make possible the use of
mild oxidation conditions.  The oxidation operation in KVB's coal
desulfurization process is carried out at atmospheric pressure
and temperatures up to 100 °C.  Coarse ground coal can be used
(-14 +28 mesh)  as the oxidizing gas penetrates the coal structure,

     KVB's coal desulfurization technology is in the early stage
of development and has the potential for a low cost chemical
coal cleaning method; however, there are still questions to be
answered.  This presentation covers the reaction conditions and
laboratory test results for the three types of sulfur removal,
oxidation, water wash, caustic wash, the chemistry of the sulfur
reactions, including a discussion of organic sulfur reactions
and preliminary process economic estimates.
                              1145

-------
 Reaction Conditions

      Ideally a  chemical  coal  cleaning  process  would  have  the
 following characteristics:
         Coal size - coarse  (+ 28 mesh)
         Temperature -  low  (ambient to  100  °C)
         Pressure - atmospheric
         Efficiency - pyritic  sulfur  (90-100% removal)
                   - organic  sulfur  (90-100% removal)
         Chemical usage - small quantity, low cost
         Selectivity - no adverse changes in the coal
         Process time - short  (1-15 minutes)

     KVB's chemical coal cleaning method has the following
characteristics:

        Coal size - 14 +28 mesh
         Temperature - ambient to 100 °C
         Pressure - atmospheric
        Efficiency - pyritic  sulfur up to 100%
                   - organic sulfur up to 40%
        Chemical usage - oxygen, some N02 and water are consumed
        Selectivity - no adverse changes in the coal
        Process time - 1 to 2 hours total

     The selective oxidation is carried out on -14 +28 mesh coal
at one atmosphere pressure and 100 to 200 °F.  The reaction time
is 0.5 to 1.0 hours.   The water wash takes only a few minutes
at atmospheric pressure and at 25 to 100 °C.  The caustic treatment
                              1146

-------
 takes place from  0.5 to  1.0 hours at atmospheric pressure and
 at  25 -  100 °C.   The total processing  time  is about  2 hours.

     KVB's coal cleaning method differs  from the ideal coal
 cleaning process  only in the time of treatment and the degree
 of organic sulfur removed; however further  development work
 could reduce these limitations.
     Background information on coal cleaning methods has been
 reviewed by Wheelock (1977) and by Mezey, Singh and Hissong
 (1976) and by Meyers (1977).  Because of the porous structure
 of coal, coarse grinding (-14 +28 mesh)  is  sufficient to expose
 the sulfur containing compounds for reaction with an oxidizing
 gas and subsequent washing.

     Nitrogen dioxide (N02) has a high enough oxidation potential
 to oxidize inorganic and organic sulfur compounds.  In the
 presence of oxygen, the NO formed from the N02 is reoxidized
by oxygen.  The oxidation by N02 and the reformation of NO, both
take place at atmospheric pressure and low temperatures.

Oxidation Sulfur  Removal

     Consider the chemical reactions:
       Fe S2 + 02  ^2?   Fe so^ (or Fe SQ^J  + SQ            (1)
                   N02
       Fe S2 + 02  -*•   FeO (Fe203)  + 2S02                 (2)
                               1147

-------
      These chemical  reactions  describe  the  removal  of  sulfur  from
 pyrites.   Table  1  shows  test results  for  four coal  samples which
 were  oxidized  with oxygen,  diluted with nitrogen  in the presence
 of  N02.   All four  coals  showed a  significant reduction in sulfur
 content after  oxidation.  No extraction or  washing  was employed.
      The  oxidations  were run in a one-inch  tubular  reactor with
 a 12-inch high static coal  bed.   No vibration or  movement of  the
 bed of coal occurred.  It is possible that  under  the test conditions
 some  chanelling  of gas through the bed  occurred and this may  account
 for some  of the  scatter of  results.
      In these  tests  total sulfur  reductions of about 20 to 50 per-
 cent  were  observed.  The reductions were  about 30 to 90 percent of
 the pyritic sulfur content.
      In these  tests  the oxidizing gas contained 5 to 10 percent
 N02-  The  total  quantity of NO, contacting  the coal at one
 atmospheric pressure varied from  1.0 to 2.5 moles N02/mole of
 total sulfur.  The direct sulfur  removal was carried out at 93 °C
with about 1000 volumes of dry gas containing one volume of coal.
     At the present time, it is not known for certain  if the
oxidation reaction with N02 takes place directly with the pyritic
and organic sulfur or through the intermediate formation of nitric
acid;  for example,
          Pe S2 + 6N02 -*  6NO + Fe S04 + S02               (3)
          NO + 1/202  -*•  N02                                (4)
                               1148

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                    Table 1.   Oxidized Coal Samples.
                           Particle Size -14 +28 Mesh
                 N02/S Mole Ratio - 1 to 2.5 - Contacting the Coal
                                               Final            % Removal
                       Pyritic              Total  Sulfur   of Total    of Initial
Coal Sample   Total  and Sulfate  Organic  After Oxidation  Initial S   Pyritic  S

Lower Kitan-   4.3       3.6       0.7           3.3           23          28
ning

Kansas         6,7       5.1       1.6           4.1           24          31
Crawford Co.                                                              29

Kansas         5.3       3.8       1.5           4.3           19          26
Crawford Co.                                    2.7           49          68

Oklahoma       3.2       1.3       1.9           2.5           22          54
Craig Co.                                       2.0           38          92
                                     1149

-------
Possible reactions
        H20 + 2N02 + 1/202  5*;  2HN03                       (5a)
        Fe S, + 6HNO- —*> Fe S04 + S02 + 3H20 + 3NO + 3N02  (5b)
Water is required for the formation of nitric acid.  The coal was
not predried and initially may have contained 1-5 percent water.
The dry gas passing over the coal would remove any water not
chemically bound.  The thermodynamic data for Reaction 5a
(Forsythe, 1942) show that for a gas mixture of:
        5% by volume N02
        5% by volume H20
        15% by volume 02
        Balance N2
at atmospheric pressure and 102 °C, the equilibrium concentration
of nitric acid is 0.7% by volume.  It is likely that this equilibrium
is not achieved at the KVB process conditions.  The contact of N02
with the coal results in selective oxidation and the formation of
NO.  The tests were run feeding NO and air which reacted to form
N02.  The concentration of N02 will be considerably less than five
percent when five percent NO is fed.  This would decrease the nitric
acid downstream at equilibrium.  The water vapor concentration
assumes that for coal containing five percent water all the water
is vaporized during the test.  This means that no aqueous phase
remains to form liquid nitric acid nor should any nitric acid
formed condense as liquid nitric acid.
                                1150

-------
      Any nitric  acid  formed which oxidized the pyrites results in
 the same net reaction as  Reaction 3.   That is, the nitric acid is
 generated in situ  and reacts.   The N02 would then function as
 indirect oxygen  carrier.

 Post Oxidation Water  Washing to Remove Sulfur
      The reaction  of  pyrites to sulfites  or sulfates  produces
 water soluble iron sulfur compounds.   These compounds can be
 washed from  the  coal.  Table 2  shows  test results for coals which
 were oxidized and  subsequently  washed with water.
         Table 2.   Oxidized  and  Water  Washed Coal Samples.


Coal Sample
Lower Kentucky
Illinois 5

Kansas
Crawford Co.
Mounds vi lie
(W. VA)
Initial

Total
4.3
3.0

5.3
5.3
5.3

Sulfur Content % Of
Pyritic &
Sulfate
3.6
1.1

3.8
3.8
2.6

Final Total
% Removal
Sulfur After of Total
Organic
0.7
1.9

1.5
1.5
2.7

Water Wash
1.6
2.0
1.9
3.0
2.5
3.2

Initial S
63
33
37
43
53
40

of Initial
Pyritic S
75
91
100
61
74
81

                                                             P-213
Organic Sulfur Removal
     Sequential oxidation and water washing reduces the  sulfur con-
tent of the coal and also the iron content and the content of other
trace element species.  Ash removal is likely since washing coal
generally reduces ash; however test verifications have not been made.
                                1151

-------
The caustic treatment is done on the partially cleaned coal to
minimize the amount of caustic used up forming iron hydroxide,
etc.  It is also desirable to remove the iron salts before treating
with caustic to avoid forming gelatinous iron hydroxides in the
pores and free spaces in the coal structure as this would impede
the contact of caustic with the oxidized organic sulfur compounds.
     Table 3 shows the results of tests which after oxidation and
water washing the coal was treated with a caustic wash for one
hour at 93 °C.  The final sulfur content was below the initial
organic sulfur content for these samples.
     To eliminate the possibility that sampling errors might have
resulted in these low organic sulfur analysis results, additional
tests were run using coal which was made pyrite-free by treatment
with nitric acid.  This treatment applied the pyritic coal analysis
procedure, ASTM D2492, (i.e., the coal was boiled in 12% HN03 for
thirty minutes, filtered and washed six times with 12% HN03) to a
large sample of coal to prepare the sample for N02 oxidation.  In
these tests (Table 3) the sulfur content was reduced indicating
that the organic sulfur was indeed being removed from the coal.

Organic Sulfur Removal Chemistry
     Using N02 as an oxygen carrier for the selective oxidation of
sulfur compounds in coal provides a strong oxidant and permits the
reactions to be carried out at ambient conditions.  It is possible
to oxidize the sulfur compounds selectively.  It is also possible
                               1152

-------
 Table 3.  Oxidized Water Washed and Caustic Washed Coal Samples.
Coal Sample
Initial Sulfur Content
      & Pyrite
Total   Sulfate  Organic
                                                        % Removal
                   of Total   of Organic
       Final Sulfur   Sulfur      Sulfur
Lower Kittaning
Illinois 5

4.3
3.0
3.0
3.6
1.1
1.1
0.7
1.9
1.9
0.5
1.0
1.2
8B
67
60
29
47
37
Moundsville
(W.  VA)*
 2.8
2.8
1.6'
43
43
* Sample was pretreated to remove pyrites.  Initially this sample analyzed 5.3%
  total sulfur, 2.6% pyritic  (and sulfates) 3.2% organic
  After oxidation and caustic treatment
                                                               P-213
to cause non-selective reactions to occur.   Depending on the

temperature,  pressure and concentration,  NO, can:

     .  react selectively to oxidize  sulfur compounds

        react with coal to form easily  decomposed nitrogen-
        containing compounds

     .  react with coal to form stable  nitrogen-containing
        compounds

        react to oxidize coal

The pyrite oxidation reactions were discussed above.  Suffice  it

to say that  if inorganic nitrates  are formed along with inorganic

sulfates, they are water soluble.  The  selective oxidation of

organic sulfur compounds is widely in the literature.  KVB has

patented a process using oxygen containing gases containing  low

quantities of nitrogen oxides to oxidize the sulfur compounds  in

petroleum fractions and subsequently  separate the oxidized sulfur
                                 1153

-------
 compounds  by methanol  extraction  (Guth,  1974).   Typical  results
 for  desulfurizing  fuel oils  are given  in Table  4.   In  these  tests
 the  oil  was  oxidized at  atmospheric  pressure  and 25 to 65  °C.  The
 oxidized oil was allowed to  degas  for  one hour.   The oil insoluble
 fraction separated and was further degased after 10 minutes  at
 150  °C.  The oxidized  degassed oil was extracted with  methanol to
 separate to  low sulfur fraction as the raffinate and the high
 sulfur oil as the extract.
     These data are presented to indicate that  the  various types
 of organic sulfur compounds  in oil fractions  can be oxidized with
 NO-  in the presence of oxygen without  forming stable nitrogen
 containing compounds.  Nitrogen compounds along  with sulfur  com-
 pounds are oxidized and  extracted.  Methanol  extraction  of unoxidized
 oil  does not separate  any significant  fractions  of  the sulfur and
 nitrogen.
     Model sulfur compounds  have been  oxidized to sulfones and
 sulfoxides by N02 in the presence  of air.  Typical  of the compounds
 are dihexyldisulfide,  benzylphenylsulfide  and dibenzyldisulfide
by KVB and dibenzothiophene  by the Bureau  of Mines  (Friedman, 1977} .
Both aliphatic and aromatic  sulfur compounds are oxidized without
nitration.
     Coal oxidation may be accompanied by nitrogen dioxide absorp-
tion under some conditions.  It may be necessary to predry the
coal to eliminate a water phase or to post heat the coal to decompose
unstable nitrogen compounds to reduce the abosrbed NO, content.
                               1154

-------
Table 4.   Organic Sulfur Compound Oxidation in Petroleum Fractions,
                         Low  Sulfur       High  Sulfur     Oil Insoluble
              Initial   % Of            % Of             % Of
Feed	%S   %N   Feed   %S   %N*  Feed   %S   %N*  Feed    %S   %N

Turbine fuel  0.15 0.03   85   0.06 0.01  14.5  0.66  0.26 0.5    0.3  0.5
  API6

Diesel oil    1.1  0.19   85   0.1   0.08  14    7.0   0.8  1.0    5.0  0.5
  APIG 34

Atmospheric   1.7  0.25   80   0.3   0.12  19    7.5   0.'8  1.0    5.0  0,5
gas oil
  APIG 28

Shale oil     0.6  1.6    85   0.4   0.3   14    1.7   9.0  1.0    0.8  1.5
  APIG 30

* After degassing one hour at 30 °C

 After degassing 10 minutes at 150  °C
                                                                     P-213
                                     1155

-------
     In coal desulfurization to remove organic sulfur, it is not
possible selectively to dissolve and separate the oxidized sulfur
compounds; however, the oxidized sulfur compounds can be hydrolyzed.
The caustic treatment hydrolyzes the oxidized organic sulfur com-
pounds in coal converting the sulfur to inorganic forms thereby
allowing the sulfur to be spearated by extractions.
     The question of NO, reacting nonselectively with coal has not
been answered.  More laboratory work is required.  If NO- reacts
with coal in a manner similar to the reactions with oils, any N02
reacting with the coal will be readily removed by heating and the
NO recovered for reuse.  If N02 reacts with coal to form more stable
compounds, then reaction conditions must be used to minimize the
nonselective N02 reaction and thereby minimize any contribution
to flue gas NOx on combustion of the coal.

Process Cost Estimate
     KVB's process has the following operations:
        Preparation of the feed - white rock removed and coal
        crushed to -14 +28 mesh size
        Oxidation - the dry crushed coal is reacted at one
        atmosphere and 100 °C with a gas stream containing
        nitrogen dioxide and oxygen
        Water washing - the oxidized pyritic sulfur is removed
        fromthe coal by a water wash at one atmosphere pressure
        and 100 °C
        Caustic washing - about 40% of the organic sulfur is
        removed by a caustic washing at one atmosphere pressure
        and 100 CC
                              1156

-------
      .  Pelletizing - about 30% to 35% of the feed coal is less
        than  28 mesh size and is balled on a disc and dried on
        a traveling grate prior to shipment.  The remainder of
        the coal can be shipped as-is.

      .  Wash  solvent treating - the process wastes, calcium
        sulfate and sodium jerosite  (sodium, iron, sulfate
        compound) are chemically separated from the water
        solvents

      There are at this time uncertainties regarding the chemical

usage and process equipment requirements.  However, KVB has made

a preliminary R.O.M. cost estimate.


      KVB used the Bechtel study comparing chemical coal cleaning

processes (Oder, 1977) as a basis for an updated cost estimate.

The Bechtel study showed that KVB was comparable in cost to other

processes under consideration.  Cost reduction in KVB's analysis

resulted mainly using a coarser grind coal.  The KVB estimate was

made  of the cost of operating an 8,000 ton/day coal treatment plant

based on the schematic shown in Figure 2.  The major cost reductions

were  in coal grinding, compaction and energy to dry coal in the pro-

cesses.  The capital cost estimate was arrived at by estimating

equipment costs and applying a factor to obtain installed equipment

costs.  The factor of 4 used by KVB is believed to be conservative.

A 30% contingency was added due to the uncertainty of the estimate.

The capital cost was estimated to be $29,000,000 as shown in Table

5, and the total cost per ton of feed was $8.50 as shown in Table 6.

Both the capital cost and the operating cost are R.O.M. estimates

based on the current understanding of the process.
                                1157

-------
Feed,
High Sulfur
Coal
                       Pulverizer
                      80 -F,  1 atm
             Pulverized Coal
               (-14 +28)
                                 Reactor
                                  200 »F
                              1 atmosphere
                          1/2 hour contact time
I
-------
           Table 5.   Capital Cost  Estimate for KVB Coal
          Desulfurization  Process  for 8,000 ton/day Feed
                               (Lump  Coal)
	Equipment	MM$
1.  Feed storage and handling,  grinding and                    1.30
    product palletizing
2.  Reactor and oxidizing gas loop                             1.3
3.  Water wash use and reclaiming                             0.7
4.  Caustic use and reclaiming                                0.7
5.  Dryer for coal                                            0.75
6.  Solids preparation for disposal                            0.10
                                      Total Equipment        4.85
    X Factor  for Installed Equipment  (X4)                     19.4
    Contractor's Fee                                          2.9
                                                            22.3
    Contingency at 30%                                        6.7
                                      Total Capital Cost     29.0
                                                                      P-213

                                    1159

-------
                Table  6.  Processing Cost Estimate  for
                   KVB Coal  Desulfurization  Process
            Feed Rate - 8,000 Tons/Day,  330 days, 2.6 MM Tons/Year

            Capital Investment,  Million  $                          29 0

Operating Costs                                                  MM$/Yr
  Direct Costs

     NO2 at $200/ton                                               ^ 6
     Oxygen at $30/ton                                             2*i
     Caustic at $300/ton                                           ^' ~
     Lime at $30/ton                                               0° ±
     Utilities (energy, water)                                      7 Q
     Labor (5 men/shift)                                            0"5
     Maintenance, 5% of capital                                     ^'.
                                      Total Direct
  Indirect Costs
     Taxes and insurance (1.8%  capital);  supervision
     (2.0% of labor);  benefits  (30% of labor plus
     supervision);  plant overhead  (50% of labor plus
     supervision)

                                      Total Indirect

  Corporate G&A (10% of direct  cost plus  indirect)

                                      Total Operating Cost
Amortization, 0.17  x capital  (15%  ROI,
     15-year life,  52% income tax  rate)

                                      Total Expense

TOTAL COST/TON OF FEED*
*Feed Coal:             Product Coal:

   Sulfur, 1.9%            Sulfur, 0.5%
      Pyritic,  1.2%
      Organic,  0.7%
                                                                      P-213


                                     1160

-------
      KVB feels that the estimated processing cost of $8 to $9/ton



 is representative of the process as is known today.




      The costs of the operations are roughly as follows:




        Storage, grinding,  pelletizing        1.50



        Oxidation                             3.00



        Water wash                            1.50



        Caustic wash                          2.50



                                              8.50/ton




      Operating with only one or  two of the desulfurization modes



 of KVB's process would  result  in lower costs.




      Oxidation only of  previously ground coal  is  estimated to



 cost  $3.00-$4.00/ton.





      Oxidation and  caustic washing for organic  sulfur removal of



 a  low pyrite  coal is  estimated to  cost about  $6.00 to $7.00/ton.





 REMARKS




      The United  States'  largest  energy resource is coal.   The



 ability efficiently to utilize this  source of energy is vital to



 the nation's  technological progress, economic well-being,  and,



perhaps, national defense.  This is  highlighted by our well-



publicized dependence on imported oil.  Unfortunately, the use of



coal as a fuel is less desirable from  an environmental standpoint



than gas or oil.  Emissions of sulfur  oxides, nitrogen oxides, and



particulate matter are more difficult  to control.
                                1161

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      The KVB process  has  the  potential  of  an  economic chemical



 coal cleaning process.  It  is an  atmospheric  pressure, ambient



 temperature  process which results in  low capital cost.  The  feed



 does not have to  be pulverized (+28 mesh has  typically been  used).



 The  chemicals used are  oxygen and nitrogen dioxide which are



 relatively low cost.  Of  particular importance  is the removal of



 a portion of the  organic  sulfur content  in addition to essentially



 all  pyritic  sulfur.   Washing  of coal  to  remove  pyrites by physical



 separation is feasible  but  requires pulverized  coal  (as fine as



 200  mesh), results in incomplete  separation,  and removes no  organic



 sulfur.   Substantial  reductions in the cost of  scrubbing can be



 achieved  by  using cleaned coal.




      KVB  has  demonstrated the  technical  feasibility of the process



 for  removal  of  sulfur from  several coal  samples.  Preliminary



 estimates have  been made  of the cost  of  treating coal and they



 compared  favorably with competing processes.  Additional experi-



mental work must  be done  to further the  process development  and



provide a basis for a laboratory  plant design (about 100 Ib/day



capacity).  Questions regarding N02 uptake by the coal and the



application to coals  previously physically cleaned to remove



pyrites must be answered.
                               1162

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      This  presentation  described  three  sulfur removal modes

associated with  KVB's chemical  coal  cleaning method:

        gas phase  - on  oxidation

        water phase - washing the oxidized coal

      .  caustic  phase - treating the water washed oxidized coal
                        for organic  sulfur removal

The test data are not extensive or complete;  however, they do

indicate that the chemical basis of this technology is sound.

     Further development will be aimed at expanding the data base,

refining the cost estimate and lowering the cost.  Applications

to coals previously cleaned by physical methods will be investigated.

     This method can be a practical means for low cost chemical

coal cleaning.
                              1163

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                           REFERENCES
Forsythe, W. R. and Gianque, W. F., J. Am. Chem. Soc. 64  (481
     1942.                                            —  ^   ' '

Friedman, S., Lacount, R. B. and Warzinski, R. p., Coal
     desulfurization chemical and physical methods.  American
     Chemical Society, Washington, D.C.  page 166.  1977

Guth, E. D. and Diaz, A. F., U.S. Patent 3,847,800.  1974.

Meyers, R. A., Coal desulfurization.  Marcel Dekher  inc
     New York, 1977.

Mezey, E. J., et al., Fuel Contaminants:  Volume 2, removal
     technology evaluation.  EPA 600/2-76-1776.  September 1976

Oder, R. R., et al.  Technical and cost comparisons for chemical
     coal cleaning.  Paper presented at the Coal Convention
     American Mining Congress.  Pittsburgh, PA.  May 1977. '

U.S. Patents on select sulfur oxidation with NO.,, 2 489 316-
     2,489,318; 2,285,744; 2,825,745; 2,581,050?   '   '

Wheelock, T. D., ed.  Coal desulfurization chemical and physical
     methods.  American Chemical Society.  Washington, D.c.
     x y / / •
                                1164

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                THE DRY REMOVAL OF PYRITE AND ASH FROM COAL
         BY THE MAGNEX PROCESS COAL PROPERTIES AND PROCESS  VARIABLES

                     James K.  Kindig and Duane N.  Goens
                            Hazen Research, Inc.
                              Golden, Colorado
                                  ABSTRACT
     The Magnex process is a dry method for removing pyrite and other ash-
forming minerals (ash) from coal.  The process works because of the action
of a chemical vapor which increases the magnetic susceptibilities of pyrite
and ash but not the associated coal.  As a result, pyrite and ash can be
removed from coal by conventional magnetic separators.

     Conventional coal cleaning processes are limited (dependent upon) the
specific gravity distribution of the coal which, in turn, is dependent upon
the naturally occurring, sometimes intimate, mixtures of coal, ash, and
pyrite.  In like manner, high gradient magnetic separators are limited by
fixed magnetic susceptibilities of the component assemblages.  In contrast,
Magnex, an applied chemical process, permits the adjustment of the magnetic
susceptibility of refuse components independent of the coal and independent
of the way nature assembled them.

     Recent detailed studies of the Magnex process variables and coal properties
are permitting us to take advantage of the selectivity of the process.  In
this regard, six coals are discussed.  The effects of pretreatment and carbonyl
treatment variables on pyrite and ash removal efficiencies illustrate the
range of control that is possible over the magnetic susceptibility enhancement
reactions.  Also, examples are given of the "best path" approach which leads
to clean coal results equivalent to perfect gravity cleaning.  Future plans for
Magnex are discussed.
                                      1165

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                            INTRODUCTION


       There exists today, a time of importance in achieving both energy and

environmental goals, a great need for an efficient and inexpensive process for

removing pyrite and ash from fine coal. The Magnex process, a novel method

for fine coal cleaning, is a candidate to fulfill that need. This paper reviews

the current status of the  process and its commercialization.   Also, it describes

current progress in a study undertaken with several coals to acquire a better

understanding of the interaction between properties of the feed coal and the

process, and the relationship between the process variables and effective

coal cleaning.

       Nedlog Technology Group, Arvada, Colorado, holds the worldwide

licensing rights to the Magnex process, and they are sponsoring the research

and development work at  Hazen Research,  Inc.  Grateful  acknowledgment is

extended to  them for their sponsorship and this opportunity to review some

aspects of the work.



                            PROCESS REVIEW

       There are four main steps in the Magnex process;

              1.   CRUSHING: To achieve liberation of pyrite and ash form-
                  ing minerals (ash);  it usually is necessary to comminute
                  to about  14-mesh.


                                 1166

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               2.  HEATING:  In this step the temperature of the feed coal is
                   elevated to about 170°C.  In addition to being a heating
                   step, preconditioning takes place which makes the car-
                   bonyl treatment more selective.

               3.  CARBONYL TREATMENT:  The iron carbonyl treatment pro-
                   vides the magnetic enhancement of the pyrite and the ash-
                   forming minerals.

               4.  MAGNETIC SEPARATION:  Pyrite and ash-forming minerals
                   are removed by medium intensity magnets as a magnetic
                   refuse while the nonmagnetic portion is a clean dry coal.

        The chemistry of the Magnex process is summarized with three equa-
tions:
                        Fe(CO)5
                         Iron
                      penta carbonyl
       Fe°
       Don
         SCO
        Carbon
       monoxide
Fe(CO)s
Iron
penta carbonyl
+ Ash
minerals
Fe°-Ash
Crystallites of
Iron on ash.
minerals
+ SCO
Carbon
monoxide
            
-------
and release carbon monoxide.  The third equation describes what happens to




the pyrite.  It reacts with iron pentacarbonyl to form a pyrrhotite-like material




and carbon monoxide.  The iron carbonyl does not react with the coal to form




a magnetic species under selected operating conditions.  After treatment, there




are ferromagnetic  iron crystallites on the ash,  and on the surface of pyrite




a pyrrhotite-like conversion which has a quite  large magnetic susceptibility.




Both can easily be removed by  magnetic separators.  In summary, the




process works because  iron carbonyl selectively decomposes on the ash and




reacts with pyrite  but will not produce any significant deposit of iron on the




surface of the coal.



       Figure I is a photomicrograph of a piece of pyrite which was carbonyl




treated.  This particle is  about 65-mesh, and the formation of the pyrrhotite-




like material can be seen on periphery and in the cracks, the lighter, brighter




material being the original unconverted pyrite.  Only a slight conversion of




pyrite to pyrrhotite-like material or only a slight deposition of iron  on the ash




is required to permit the particles to be magnetically drawn into the refuse.




Photomicrographs  of a feed coal, clean coal, and refuse from a  typical Magnex




separation are shown in Figures  2,3, and 4.
                                   1168

-------
Photomicrograph of pyrite after  treatment with iron carbonyl    275X
                          Figure 1
          Untreated feed coal. Minus 65-mesh  200X
                          Figure 2
                            1169

-------
Nonmagnetic clean coal.  Minus 65-mesh    200X
                   Figure 3
    Magnetic refuse.  Minus 65-mesh   90X
                  Figure 4
                      1170

-------
       The Magnex process was invented at Hazen Research in 1975.  Since




that time there have been numerous bench scale studies of the process.




Magnex processing involves pretreatment and carbonyl treatment of crushed




coal.  The pretreatment and carbonyl treatment are done in a rotating glass




reactor; the magnetic separations are made  on a laboratory crossbelt separa-




tor.  In addition to the supporting analytical work, other tests were performed




to determine the process mechanisms and to improve the selectivity.




       Based upon the successful laboratory development program and a




favorable economic study,  a 200 Ib/hr pilot plant was designed and con-




structed to test the process on a continuous basis.  A feed coal for the pilot




plant was obtained from the Allegheny Group coals and crushed to 14-mesh.




The coal was pretreated, iron carbonyl treated, and magnetically separated;




crushing and magnetic separation were not  continous with pretreatment and




carbonyl treatment.  Crushing was accomplished with a jaw and impactor



 crushers.  Indirect heating, and pretreatment with steam at atmospheric pres-




sure  were done while the  coal passed through a screw conveyor.  Carbonyl




treatment was accomplished in  a  shaft furnace with a very slow co-current




flow of iron carbonyl gas,  also at atmospheric pressure. Magnetic separa-




tion was completed with a  commercially  available induced magnetic roll




 separator. These pieces of equipment were a  convenience for pilot plant




operation and are not necessarily the ones which would be used in a larger




 installation.



        The pilot plant was operated continuously during five campaigns; each






                                    1171

-------
 campaign lasted from four to six days.  Coal processed continuously through

 the pilot plant behaved as expected from laboratory tests on the same coal.

 Samples from the pilot plant operation met the EPA limits for SO2 emissions from

 new sources, 1.2 pounds/million Btu.  Data showing the quality of clean coal

 in comparison to feed coal are given in Table 1.

                                 Table 1

                   Comparison of Feed and Clean Coal:
                            Pilot Plant Results




Clean coal
Feed coal
Pyritic Total
Yield Ash, Sulfur, Sulfur,
Weight % % % %
82.3 14.8 0.07 0.73
100.0 18.1 0.62 1.22
Calorific
Value ,
Btu/lb
12,520
11,981
Pounds of
Sulfur/
MM Btu
1.17
2.03
       An economic study based upon data obtained from the pilot plant

showed that the operating cost was about equal to the cost of cleaning fine

coal in existing coal preparation circuits.

       Current plans and activities include:

               1.   Intensive studies on iron carbonyl generation.  This work
                   has been most  successful and is now in the pilot plant
                   stage.

              2.   Intensive search for alternate magnetic separators to
                   separate large volumes of dry solids efficiently and
                   inexpensively.   This work is just under way.

              3.    Operate the pilot plant again, but with the coal selected
                  for the demonstration  plant.  Provide support for the
                  design engineers.

              4.   Design a coal preparation flowsheet which employs the
                  best blend of the advantages of conventional coal pro-
                  cessing and the Magnex technology.


                                  1172

-------
               5.   Improve the scope and efficiency of the process and reduce
                   the cost.

               6.   Proceed to a demonstration plant, about 60 TPH.

       This completes the process review and status; following are two

studies or evaluations dealing with the effect of the coal properties on Magnex

beneficiation, and the relationship between process variables and Magnex

beneficiation.
                    EFFECT OF COAL PROPERTIES ON
                   MAGNEX BENEFICIATION OF COAL

       When cleaning coal of a given size range with any gravity separator

(jig, table, heavy media, etc.), it is the specific gravity of the coal, ash, and

pyrite particles, whether free or locked, which determine the kind of separation

obtained.  This specific gravity distribution is not subject to human control.

Likewise,  a magnetic  (HGMS) separation of raw coal (no  Magnex treatment)

is dependent upon the relative naturally occurring magnetic susceptibility of

the various particles and also is not subject to human control.  In contrast,

the Magnex process permits the controlled enhancement of the magnetic sus-

ceptibility of particles containing ash or pyrite while not affecting particles

of clean coal.  This selectivity, the ability to enhance magnetic susceptibility

of refuse but not coal, is the great opportunity and challenge of the Magnex

process.
                                    1173

-------
COAL CHARACTERISTICS




       During the development of the Magnex process, numerous coals were



tested for their amenability to the process.  These tests were done in the



laboratory on a batch basis; however, many results have shown the good agree-



ment between laboratory and pilot plant results.  Coals from several  localities




were tested.  These coals differed considerably in their responsiveness to



carbonyl  treatment and were included in this study for that reason. Of course,



differences should be expected because of the highly variable nature  of coal



and associated minerals,




       An intensive  study was mounted on seven coals which varied  in their




response to the process.  The purpose of the study, which is still in progress,



is to learn which properties of coal influence the process and to determine how




process variables could be changed to bring about improved results.  The  coals



considered are listed in Table 2.





                                Table 2

HRI Number
11986-1
12683
11986-2
11089
7265
6776-1
6145
Identification of Coal Samples

Seam
Lower Freeport No. 6A
Pittsburgh No. 8
Pittsburgh No. 8
Allegheny Group Coals
Illinois No. 6
Lower Freeport
Lower Freeport

State
Ohio
West Virginia
Ohio
Pennsylvania
Illinois
Pennsylvania
Pennsylvania
                                 1174

-------
       Each of these coals was tested for those coal properties which were

thought might be related to its response to the process.  A listing of these

coal properties is given in Table 3.  The last five analyses included in the list

are tests which are not ordinarily determined in coal. They are included

because study and correlation of the previous test work has suggested a

relation between them and the process.



                                Table 3
                          Feed Coal Properties
                        Ash
                        Pyritic sulfur
                        Organic sulfur
                        Total sulfur
                        Calorific value
                        Sink float tests

                        Low temperature volatiles
                        Tendency to  produce acid
                        Heavy metal analysis
                        Pyrite size
                        Elemental sulfur
BENEFICIATION TESTS BY THE MAGNEX PROCESS

        Each of the seven coals was then beneficiated by the Magnex pro-

cess.  This involved crushing, and magnetically separating the treated

material to produce a clean coal and refuse. The clean coal, refuse, and

feed were then analyzed for ash, forms of sulfur, and calorific value (Btu/lb)

These data and other analyses performed on the feed coal appear in Table 4.


                                 1175

-------
                                                                                                      Tablo4

                                                                          Analyses of Food, Clean Coal, and Solatia lot Seven Minus 14-mooh
                                                                                     _£QalgBGnQflcIated bv tho Maflnon

Sample Identification
Lower Freepon No. 6A
Ohio
HRI 11986-1
Pittoburgh No. 6
West Virginia
HRI 12683
Pittsburgh No. 8
Ohio
HRI 11986-2
Allegheny Group Coals
Pennsylvania
HRI 11039
minols No. 6
nllnols
HRI 7265
Lower Prooport
Pennsylvania
HRI 6776-1
Lower Freeport
Pennsylvania
HRI 6145
^ Btu/SO2 Index (Bj)
£/ Percent theoretical
D. theoretical aooui
GT^aillC IDfltTTTlfll .
3/ Percent of Darfoct.g
Yield,
Weight
Clean coal 74.5
Refuse 25.5
Feed
Clean coal 83.7
Refuse 16.3
Feed
Clean coal 84.4
Refuse 15.6
Feed
Clean coal 66.6
Refuse 13.4
Feed
Clean coal 79.4
Refuse 20.6
Feed
Clean coal 89.2
Refuse 10.8
Feed
Clean coal 72.7
Refuse 27.3
Feed
Bfu recovery
Pyrttlc Organic
Sulfur, Sulfur*
18.4 0.69
76.8 7.08
34.3 2.32
21.0 1.24
60.7 9.46
27.5 2.38
26.0 1.52
61.0 10.8
33.3 2.76
16.3 0.07
38.5 4.32
19.7 0.64
12.9 0.94
59.6 S.4S
25.5 1.87
23.9 0.57
' 62.9 11.2
27.9 1.72
9.4 0.33
73.6 6.19
25.7 1.93

Sulfur-to-Btu ratio
claanln,, (PTC! «. B, feed - B, clcon coal
0.70
0.66
2.34
2.26
1.63
1.36
0.65
0.66
3.34
3.01
0.51
0.66
O.S5
O.S8
n 100
Total
Sulfur,
1.39
6.97
. 2.98
3.58
8.89
4.64
3.15
11.3
4.32
0.72
4.24
1.30
4.28
5.69
4.33
1.06
13.0
2.38
0.88
7.28
2.51

B. feed ~ B_ theoretical
DOS comploto pyrlto and aoh raaoval but no Btu loco from
ravlty cleaning, tha ratio of aoh or pvxltlo oulfur mmnvod by

Calorific
Value, Ash.
Btu/lb X
11.953
2.326 53.6
9.320
11.605
4.037 36.0
10.505
10,644
3,446 32.9
9,433
12,178
3,517 26.8
11.616
11,891
4.818 54.5
9.977
11,419
4.498 24.2
10,707
13,970
2.980 74.7
11.S04
Reloction
Pyrttlc Total Btu
Sulfur. Sulfur. Recovery.
XXX
95.5
77.8 63.2
92.5
59.8 32.6
95.2
56.9 39.9
90.6
90.5 47.7
94.6
60.0 25.6
95.1
70.3 59.3
88.3
67.6 75.7
Sulfur
OKldes.
Pounds/
1068tu
2.32
6.39
6.16
5.82
5.92
9.15
1.18
2.24
7.19
9.77
1.69
4.44
1.26
4.36
Btu/BO.
41.2
15.6
15.0
11.3
16.1
10.9
76.9
44.6
13.2
10.2
50.4
22.5
70.2
22.9
Ponont of
2/ Perfect
Percent Gravity '
Thoor. Cleaning,
Clean- PyrtUo
^ Ash Sulfur
47 68 221
27 52 272
22 49 157
75 -37 117
46 76 72
48 40 136
63 -
LowV ItetS/
Fompoxatuio Add
Arbitrary tlon Zinc. Copper.
Units X SO^" ppm ppm
92.0 0.63 100 5
303.6 0.194
116.5 0.330 53 17
12.7 0.182 140 13
86.0 O.S9 90 53
19.0 - 61 17
9.S - 46 17 •
Weight
Mean
Pyrtto
Micron
556
619
405
419
641
S13
4/ Low tamporaturd volatilos , quantity of gao given off by fronting tho coal to 200°C for ftvo
mlnutoo. Qouosocd In arbltfery units.
S/ Net add production, amount of add found by sparging' oxygon through a coal-cater oluny
at 7S°C for 24 hours loss tho amount of add resulting from oparglng with nltrogon.
Ejtulusoed in porcont 8Od°>
•Jie process to tho aoh or pyrttlc oulfur laiuuvcJ by olni-Ooat at the oame yield
times 100.

-------
        To Judge the effectiveness of the separations ,  several criteria derived




from the analytical data are useful.  For steam coals,  it is desirable to maxi-




mize Btu recovery and minimize the sulfur- to-Btu ratio; for this reason "Btu




recovery" and "pounds of sulfur oxides per million Btu" are calculated.




Btu/SC>2 Index (B_) is a combination of Btu recovery and sulfur-to-Btu ratio;




it is defined as follows:
                Btu/S02 Index 2  per million Btu contained in the feed.  Clean coal has lower




Btu recovery but also lower SO2 values.  High B, values are desirable,




reflecting good Btu recovery and low sulfur-to-Btu ratio.




        For comparisons between coals, the B  value is used to develop the




percent of theoretical cleaning (PTC).  It is calculated as follows:





                                    B  feed - B  clean coal

                         PTC   =    — - - l -
                                     B feed - B  theoretical





Bj theoretical is the calculated value for complete ash and pyrite removal




with no loss of Btu from loss of organic material.




        In addition to the above, an efficiency measure  is needed which con-




siders the cleaning achieved relative  to that theoretically attainable by sink-




float methods.  The ash error (difference in sink-float and clean coal ash at




the same yield)  and the Frasier-Yancy or organic efficiency  (relationship of




yield of clean coal relative to yield of sink-float coal at the same ash value)






                                   1177

-------
are two such measures.  A similar criterion used in this work is the "Percent

of Perfect Gravity Cleaning;" it is the ratio of ash or pyritic sulfur removed by

the process to the ash or pyritic sulfur which is removed by sink-float at the

same yield.

CORRELATION STUDY

       Having described some of the criteria for judging the effectiveness of

the separation, the data of Table 4 can be reviewed for trends.  A complete

correlation study was made on all of the data by developing the simple cor-

relation coefficients for each data pair.  Selected correlations are  shown in

Table 5. The significance and utility of the  correlations for understanding

and controlling the process are now being  evaluated.  The correlation study

supports the following statement.  A high quality Magnex separation is

associated with the following properties of the feed coal:

                 1.   Small amount of low temperature volatiles.

                 2.  A tendency to produce acid.

                 3.  Lower levels of  copper  and perhaps higher levels of
                    zinc.

                 4.   Lower pyrite and organic sulfur content.

This information, and other information expected when the correlation study

is completed can be used to improve  the process, to characterize feed coals,

or to lead to an understanding  of the  process mechanism.
                                  1178

-------
              Correlation of Feed Coal Properties with the
             	Results of Magnex Cleaning	
          (Numbers are the simple correlation coefficients, r)
Low Temperature Volatlles In the Feed Coal (7 Coals Correlated, r >0.6

       0.71+       Pyrltlo sulfur in the clean coal
       0.67+       Total sulfur in the clean coal
       0.69+       Pounds of SO2/MM  Btu In the clean coal
       0.65-       Pyrite rejection
       0 . 74-       Percent theoretical cleaning £/
Net Acid Production of the Feed Coal    (5 Coals Correlated, r >0.5

       0.84+       Organic sulfur in the clean coal
       0.75+       Total sulfur in the clean coal
       0 . 74+       Pounds of SO2/MM Btu In the clean coal
       0.5S-       Pyrite rejection
       0.82-       Total sulfur rejection

Zinc in Feed Coal (6 Coals Correlated , r >0 . 5

       0.54-       Pyritic aulfur In the clean coal
       0.75-       Ash in the refuse
       0,55-       Pyritic sulfur in the refuse
       O.S8-       Total sulfur in the refuse
       0 . 75+       Btu  in the refuse
       0.58+       Percent theoretical cleaning

Copper in Feed Coal (6  Coals Correlated, r >0.5)

       0.91+       Organic sulfur in the clean coal
       0.79+       Total sulfur in the clean coal
       0.74+       Pounds of SO2/MM Btu in the clean coal
       0.53-       Pyritic sulfur rejection
       0.71-       Total sulfur rejection

Pvrltic Sulfur in the Feed Coal (7 Coals Correlated,  r >0.6)

       0.88+       Pyritic sulfur in the clean coal
       0.74+       Ash in the refuse
       0.65+       Pyritic sulfur in the refuse
       0.82-       Btu  in the refuse
       0.71-       Btu  rejection
       0.91-       Percent theoretical cleaning

Organic Sulfur in the Feed  Coal  (7 Coals Correlated, r >0.6

       0.73-       Pyritic sulfur re] ectlon
       0.87-       Total sulfur rejection
I/  Low temperature volatlles ,  quantity of gas driven off of the coal
    at 200°C in five minutes.
2/  Net acid production, amount of acid formed by oxygen sparging a
    coal-water slurry at 7S°C for 24  hours less the amount of acid
    resulting from sparging with nitrogen.
3/  Percent of theoretical cleaning is the difference between the ratio
    of Btu recovery to pounds of SOj per million Btu in the feed minus
    that ratio in the clean coal, divided by the difference between
    that ratio In the feed and that ratio in a theoretically perfectly
    cleaned  coal , complete recovery of organic Btu and complete
    rejection of pyrite and ash.  See text, page 13.
                                1179

-------
        For the Magnex test on the Lower Freeport No.  6A coal (HRI 11986-1),

 221% more pyritlc sulfur was removed than could have been removed by perfect

 gravity cleaning at the same coal yield; however, only 68% as much ash was

 removed as could have been removed by sink-float.  This shows the extreme

 selectivity of the Magnex process for removing pyrite.  Greater than 100% of

 perfect gravity cleaning is possible because the Magnex process cleans coal

 on the basis of the magnetic susceptibility of the refuse rather than its specific

 gravity. For example, a locked coal-pyrite grain which floats could be pulled

 into the refuse by the Magnex process or a piece of bony coal which sinks

 might be left in the Magnex clean coal.


                  THE RELATIONSHIP BETWEEN PROCESS
                 VARIABLES AND MAGNEX BENEFICIATION

       In each of the four steps  of the Magnex process there are several con-

trolling variables.  A listing of some of these is given in Table 6.  The study

of these variables  Is by no means complete; in fact, for some of the steps

(crushing and magnetic separation) it has just begun,

PYRITE SIZE  DISTRIBUTION

       Most of the development  work on this process used coal crushed to

14-mesh. This size was chosen because it gave substantial liberation of

pyrite as Judged from examination of polished sections.  An objective measure

of pyrite size distribution was desired to determine if there  was a correlation

between pyrite particle size and  pyrite removal.
                                   1180

-------
                                Table 6

                       Selected Process Variables
                    Crushing:
                        Top size
                        Size consist

                    Pre treatment:
                        Time
                        Temperature
                        Atmosphere (steam)

                    Iron carbonyl treatment:
                        Time
                        Temperature
                        Iron carbonyl concentration
                        Cotreatment with other gases

                    Magnetic separation:
                        Type of separator
                        Field strength
                        Gradient
       The size determination was made by examining numerous polished

sections of coal. For each coal, 1,500 pyrite grains larger than 5 microns

were measured.  The measurements were carried out by subjecting the high

optical quality polished sections to automatic image analysis. The analysis

used a television scanner connected to a microscope.  Based on its reflec-

tivity/only pyrite grains were measured, and measurements, area and shape,

were processed by a Quantimet 720 image analysis computer. The  weight dis-

tribution was calculated from an area measurement of each grain.
                                  1181

-------
        Table 7 shows the weight mean diameter of pyrite (50% by weight of

 the pyrite has smaller, or larger, diameters) and the frequency mean diameter

 of pyrite  (50% of the grains have smaller, or larger diameters).  Additionally,

 the table shows the weight distribution of coal between 5, 25, 50 microns,

 and greater.  Considering the small percentages of pyrite in the  ranges 5-25,

 25-50, and 50-100 microns  and the mean pyrite size, which ranges from

 about 490 to 640 microns, removal of the coarse pyrite becomes  extremely

 important.  Regarding the finest pyrite grains,  even if none of these were

 removed,  they would make only a minor contribution  to the sulfur content of

 the clean coal.

 CARBONYL TREATMENT

        For the carbonyl treatment,  the variables time, temperature, and

 amount of iron carbonyl have to be fixed  such that the desired result is

 obtained. Also, the carbonyl treatment can be  applied to a coal  which either

 has or has not been pretreated.  A half-replicate 24 factorial experiment was

 conducted with the Lower Freeport No. 6A,  Ohio, HRI 11986-1, coal to test

 the effect of pretreatment and the three named variables.  (A portion of this

 work was  sponsored by the Ohio Department of  Energy, Grant No. 77-10).

        The amount and quality of the clean coal provided the bases for judg-

 ing the effectiveness of the  separation.  Specifically, the responses evaluated

for the clean coal were:
                        Measured responses:
                              Yield
                              Ash
                              Pyritic sulfur
                              Calorific  value


                                  1182

-------
                                                                          Table 7
oo
U>
Data on the Size Analysis of Pyrlte In Coal
(Coal crushed to minus 14-mesh)
Coal Identification
HRI Number
11986-1
12683
11966-2
11089
7265
6145
Seam
Lower Free port No. 6A
Pittsburgh No. 8
Pittsburgh No. 8
Allegheny Group coals
Illinois No. 6
Lower Free port
State
Ohio
West Virginia
Ohib
Pennsylvania
nilnols
Pennsylvania
Weight I/
Mean Diameter
of Pyrlte ,
Micron
556
619
505
491
641
513
Frequency 2/
Mean Diameter
of Pyrite,
Micron
21
16
22
24
20
26
Size Distribution in Percent
Weight Basis
5-2S
Micron
0.3
0.3
0.4
0.8
0.2
0.3
25-50
Micron
0.8
0.8
1.4
3.1
0.5
1.2
50-100
Micron
2.0
1.4
3.7
8.8
1.4
3.5
>100
Micron
96.9
97.5
94.5
87.3
97.9
95.0
       I/  Fifty percent of the weight of pyrite Is smaller or larger than the diameter shown.

       2/  Fifty percent of the pyrite grains have diameters smaller (or larger) than the diameter shown.

-------
                          Calculated responses:
                              Btu recovery
                              Sulfur-to-Btu ratio
                              Btu/SO2 index  (Bj)

       The range of the Btu/SO,, Index  (BT) for  the Lower Freeport No. 6A,
                              ^         1

 Ohio,  HRI 11986-1, coal is from 15.6,  the value for the feed coal, to 69.2,

 the theoretical maximum B  value attained by 100% pyrite removal with no loss

 of Btu from loss of any organic material.  The results of the factorial experi-

 ment appear in Table 8.

       The effect of the carbonyl treatment variables within the ranges tested

 on the  amount and quality of the coal are given in Table' 9.

       An analysis of the experimental  data shows the direction of a "best

 path" for further experimental  study.  The path  followed, along which the Btu/

 SC>2 Index  is Increased, requires an additional 9.2  pounds of iron carbonyl/

 ton feed for every five-degree decrease in process temperature. This

path was followed, starting at 170°C and 25 pounds Fe(CC»5/ton coal.  This

starting point was the base level for temperature and dosage, which were the

most significant factors in the fractional factorial design experiment.  Steam

treated coal was used as feed to the carbonyl reactor since steam pretreatment

 improved  the Btu/SO, Index.  Treatment time was held at 60 minutes rather than

 30 minutes since this longer time improved the  index slightly.  The experi-

 mental conditions and analytical data for these "best path" tests are given in

 Table  10,  Figure 5 shows how the "best path"  experiment leads the B  value to

 a maximum and pyritic sulfur to a minimOm.


                                 1184

-------
                        Table 8

Clean Coal Analyses Resulting from Various Combinations of
         Pretreatment and the Carbonyl Treatment
(Lower Freeport No. 6A
Pretreatment
£ No
Cn
No
No
No
Yes

Yes
Yes
Yes
Feed
I/ Duplicated
2/ Calculated
Ib Fe(CO)5/
Time , Temperature , ton
mln °c Feed Coal
30
30
60
60
30

30
60
60

150
190
150
190
150

190
150
190
"
10
40
40
10
40

10
10
40
"
to evaluate equipment change.
from Btu = 14961.8 - 162.3 (% ash)
3/ B - (% Btu recovery)/(lb SO,
/106 Btu).
' Yield oi
Clean C<
Weight
85.3
69.2
60.9
91.4
85. al/
88.3
86.2
93.2
65.1
100.0
- 32.2 (%

f
jal. Ash,
% %.
26.2
15.3
9.9
30.2
29.1
30.3
27.3
33.2
12.4
34.3
pyritic sulfur).

, Ohio, HRI 11986-1)

Clean Coal Analytical Values
Total Sulfur, Pyritic Sulfur,
2.39
2.22
1.69
3.02
1.54
1.50
2.72
2.12
1.94
2.98


1.66
1.42
0.88
2.41
0.89
0.88
2.05
1.42
1.10
2.32


Calculated
Btu/lb
10,656
12,433
13,327
9,983
10,211
10,016
10,465
9,528
12,914
9,321



IbSOz/
106
Btu
4.48
3.57
2.53
6.04
3.01
2.99
5.19
4.45
3.00
6.39



Btu
Recovery ,
97.5
92.3
87.1
97.9
94.0
94.9
96.8
95.3
90.2
• 100.0



Btu/SO2
Index (B...3/
21.8
25.9
34.4
16.2
31.2
31.7
18.7
21.4
30.1
15.6.



-------
                                 Table 9

              The Primary Effects Within the Range Tested of
       Pretreatment and the Carbonyl Treatment Variables Temperature,
           Time,  and Amount of Iron Carbonyl on the Clean Coal
                (Lower Freeport No. 6A,  Ohio,  HRI 11986-1)
	.	Desired    Undesired

Increasing the Amount of Fe(CO)5 Affects
the Clean Coal	

      Yield,  weight percent                                    Decreases
      Ash percent                                 Decreases
      Pyritic sulfur                                Decreases
      Sulfur-to-Btu ratio                           Decreases
      Btu recovery                                             Decreases
      Btu/SO- index                               Increases

Decreasing Temperature (Carbonyl Treatment)
Affects the Clean Coal	

      Pyritic sulfur                                Decreases
      Sulfur-to-Btu ratio                           Decreases
      Btu/SO2 index                               Increases

Increasing  Time  {Carbonyl Treatment) Affects
the Clean Coal	

      Btu recovery                                            Decreases
      Btu/SO2 index                               Increases

Pretreating  the Coal Affects the
Clean Coal	
      Pyritic sulfur                                Decreases
      Sulfur-to-Btu ratio                           Decreases
      Btu/SC>2 index                               Increases
                                1186

-------
oo
                                                                           Table 10

                                                   "Best Path* Experiment for Optimization of Magnex Response
{Lower Freeport No. 6A, Ohio, HRI 11986-1)
Temperature ,
°C
170
165
160
1S5
150
140
Feed
Ib Fe(CO)5/
ton
Feed Coal
25
34.2
43.4
52.6
61.8
80.2
-
Yield of
Clean Coal,
Weight %
80.0
80.4
86.1
82.9
86.8
89.5
100.0

Ash,
23.7
23.9
29.1
25.6
28.9
31.7
34.3
Clean
Total Sulfur,
2.08
1.92
1.50
1.46
1.40
1.41
2.98
Coal Analytical
Pyritlc Sulfur,
1.41
1.17
0.77
0.78
0.75
0.78
2.32
Values
Calculated _!/
Btu/lt>
11.070
11,045
10,214
10,782
10,248
9,792
9,321
IbSOz/
106
Btu
3.75
3.47
2.93
2.71
2.73
2.88
6.39
Btu Recovery.
95.0
95.3
94.3
95.9
95.4
94.0
100.0
Btu/SO2
Index (B , "^
25.3
27.5
32.2
35.4
34.9
32.6
15.6
    I/  Calculated from Btu =  14951.8 - 162.3 (% ash) -  32.2 (% pyrltic sulfur).
    2/  Bj  = (% Btu recovery)/(lb SO2/106 Btu).

-------
36 r*"
                                       -I 1.5
  I     2345678

   UNITS OF F«{CO)j , 9.2 Ibs/T AND TEMPERATURE, 5° C
                                         0.6
 CHANGE IN Btu/S02  INDEX (Bj) AND PYRITIC
 SULFUR IN THE CLEAN COAL BY FOLLOWING
 THE BEST PATH.  (LOWER FREEPORT N0.6A,
 OHIO,  HRI 11986-1)(IRON CARBONYL INCREASED
 9.2 lb*/TON FOR EACH 5*C TEMPERATURE RISE)
                  FIGURE 5
                    1188

-------
STEAM PKETREATMENT


       For the pretreatment,  the variables time, temperature, and the steam


atmosphere need to be fixed in order that the subsequent steps in the Magnex


process will yield the desired result. The effect of temperature and amount of

                                                                     2
steam were tested in a partially replicated factorial design experiment,  3 .


Time of pretreatment was set at one hour, an arbitrary setting based upon pre-


vious work. The data generated by the experiment appear in Table 11.  The


conditions employed for the carbonyl treatment were the same as those used


in the "best path" experiment which gave the best result.  The responses


evaluated were the same as those considered in the carbonyl treatment evalua-


tion.


       Within the limits tested, the effect of the steam pretreatment variables


on the amount and quality of  the clean coal  are summarized in Table 12. It is


speculated that the advantages brought about by steam pretreatment are due to


a reduction in the low temperature volatiles and, based on work not reported


in this paper, the small amount of elemental sulfur present in the feed coals.


       A comparison between sink-float results and the beneficiation obtained


by Magnex is plotted in Figure 6.  Three Magnex results are plotted.  The first


is the preliminary amenability; the second is the result of studying the variables


affecting carbonyl treatment, the best path results; the third builds upon the


second but is enhanced by the results of studying the variables of pretreat-


ment.
                                  1189

-------
                                                                               Table II
vo
O
Clean Coal Analyses Resulting from Various Combinations
Temperature and Steam Durinn Pretreatment
(Lower Freeport No. 6A, Ohio, HRI
Temperature ,
°C













I/
I/
170
170
170
200
200
200
200
200
230
230
230
230
Feed
Steam,
Ib/ton
90
252
426
90
90
252
252
426
90
252
426
426
—
Yield of
Clean Coal
Product Weight %
Cleaned Coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
Cleaned coal
—
Calculated from Btu = 14961.8- 162.3
B = {* Btu reoovery)/ttb SO2 per 106
75.6
80.9
74.5
87.9
84.9
86.7
87.8
84.9
90.6
91.4
90.6
91.1
—
x * ash -
Btu).
11986-1)
of



Clean Coal Analytical Values
Ash,
22.4
24.5
18.4
29.5
27.6
30.3
31.0
27.5
34.8
29.9
32.2
33.5
34.3
32.2 x %
Total Sulfur, Pyritic Sulfur I/ Calculated
% % Btu/lb
1.36
1.39
1.39
1.44
1.29
1.27
1.31
1.35
1.33
1.33
1.31
1.32
2.98
pyritic sulfur.
0.74
0.76
0.69
0.82
0.69
0.68
0.77
0.71
0.75
0.76
0.75
0.79
2.32

11,303
10,961
11,953
10,148
10,460
10,023
9,906
10,476
9,290
10,085
9,712
9,500
9,321

IbSO,/
106B&
2.40
2.53
2.32
2.84
2.46
2.53
2.54
2.57
2.85
2.63
2.69
2.78
6.39

Btu Recovery
*
91.7
95.1
95.5
95.7
95.3
93.2
93.3
95. 4
90.3
98.9
94.4
92.8
100.0

Index, (Bx)
38.2
37.6
41.2
33.7
38.7
36.8
35.3
37.1
31.6
37.6
35. 1
33.4
IS. 6


-------
                               Table 12

              The Primary Effects Within the Range Tested of
          Temperature and Amount of Steam During Pretreatment
         	on the Clean Coal	
              (Lower Freeport No. 6A, Ohio, HRI 11986-1)
                                             Desired
                      Unde sired
Decreasing the Temperature Affects
the Clean Coal	
      Yield, weight percent
      Ash percent

Increasing the Amount of Steam
Affects the Clean Coal	
      Ash percent
      Btu recovery
                      Decreases
     Decreases
Appears to decrease
Appears to increase
                                  1191

-------
 1001-
                           2.20
  95
o
UJ
oc

13
(-
CD
             1.50
SINK FLOAT OF
MINUS 14-MESH
  90
  66



  85
            I.40O


           	L
                                              .	O
                                               SINK FLOAT OF
                                               8-INCH BY I00-MESH
                                            1.40
JL
_L
              12345

                   POUNDS OF SULFUR DIOXIDE PER MILLION BTU



             JT) FIRST MA6NEX  AMENABILITY TEST


             g) CARBONYL TREATMENT VARIABLES OPTIMIZED


             f?) STEAM PRETREATMENT VARIABLES OPTIMIZED
                (NUMBERS BY POINTS ARE SPECIFIC GRAVITIES)
                COMPARISON OF MAGNEX AND SINK FLOAT
                FOR  BTU  RECOVERY AND  SULFUR EMISSION
                                FIGURE 6



                                   1192

-------
                             CONCLUSIONS




      The Magnex process is a novel dry method for cleaning fine coal which




is projected to be cost competitive with existing processes.  The Magnex




technology possesses a considerable advantage over most existing processes.




That advantage is the ability to make a coal-refuse separation by increasing




the magnetic character of the refuse components of the raw coal but not the




coal itself; this selectivity is contrasted to having to "live with" the existing




distribution of whatever property is used for making the separation. At the




present state of Magnex technology  that advantage is best reflected in the




considerable selectivity of the process for pyrite, and it  is likely that advan-




tage can best be exploited in conjunction with conventional coal preparation




technology.



      This paper has discussed two aspects of the ongoing commercialization




effort — (1) the effect of feed properties and  (2) the effect of process variables




on the Magnex process.  An understanding of the interaction between feed




characteristics and the process can lead to selection of preferred feed coals,




to a better understanding of the process  mechanism, and  to process improve-




ments.  Regarding the effect of process  variables, pyrite size consist data




were given; for one  (typical) coal the weight mean diameter was 556 microns.




Also shown for this  same coal was the way pretreatment variables and car-




bonyl treatment variables could be adjusted to produce a  clean coal with a




higher Btu recovery and lower sulfur-to-Btu ratio than could be achieved with




a perfect sink-float separation.  This illustrates how an  understanding of the
                                  1193

-------
relationship between process variables and the effectiveness of the separa-




tion leads to process optimization.




      A coal beneficiation process which is cost effective and produces a




sharp separation requires a  thorough understanding of the interactions between




the coal characteristics and the process, and the relationship between process




variables and the cleaning efficiency.  It is through the studies described in




this paper and the ongoing effort that this understanding is being won.
                                   1194

-------
                             REFERENCES

Carlton, Herbert E., and Oxley, Joseph H. 1965.
       Kinetics of the Heterogeneous Decomposition of
       Iron Pentacarbonyl.  AICHE J. 11(1), 79-84 (1&65)
                                 1195

-------
PANEL DISCUSSION
   1196

-------
                             PANEL DISCUSSION ON
                   PROPSECTS FOR CHARACTERIZATION AND REMOVAL
                         OF ORGANIC SULFUR FROM COAL

                             Preliminary Comments
                                      by
                               Sidney Friedman
                      Pittsburgh Energy Technology Center
                           Pittsburgh, Pennsylvania
      Until  about  1970, little  interest was shown in characterizing  Che

 organic  sulfur  in coal, and even less in removing it.  In  earlier work

 done  in  numerous  research laboratories throughout the world,  sulfur

 analyses were not routinely carried out or reported on products  resulting

 from  reactions  performed on coal.  Coal liquefaction products seldom had

 sulfur contents reported, and  though someone must have determined the

 sulfur content  of coal acids obtained by air oxidation, I  could  not find

 such  data when  I  started looking for it." Here I must admit that this

 data  was not available even in our own laboratory.  With such indifference

 about coal sulfur content, it is no wonder that we know so little,about

 it. We do not even have a satisfactory procedure for determining organic

 sulfur in coal, although several methods are being explored.  These

 include  such techniques as X-ray fluorescence and low-temperature ashing.

The lack of a reliable, direct determination of organic sulfur in coal

is particularly annoying in the case of treated coal, especially desulfurized

coal.  In these samples,  anomalous organic sulfur values are obtained

because of apparent errors in the determination of the other  sulfur

forms.  This may lead to erroneous conclusions.  Hopefully, the  aforementioned
                                    1197

-------
  new nethods for organic sulfur determinations will be developed to the


  point where they can be applied satisfactorily to treated coals.


       Characterization of the organic sulfur by functional group is an


  equally challenging problem.   Repeated attempts to determine thiol and


  alkyl thioether  group, in  coal by  classical methods have led to inconclusive


  results and there  is  no  good  evidence  to  either accept  or reject their


  presence.   Undoubtedly,  both  such  groups  exist  in  coal,  but  as  yet ther


  is no  good  procedure  for their determination.



      Current evidence  from hydrogenation studies, oxldative desulfuri


 and alkaline extraction does point to two types of organic sulfur in


 coal. Roughly half the organic sulfur is amenable to removal by thes


 methods, indicating its presence in some types of structures which


 rather easily desulfurized, e.g., thiols,  linear thioethers   TH»
                                                            •   me remainder

 of the organic sulfur appears to resist these treatments, although it


 can be removed by treatment that cleaves such sulfur compounds «* ^.u
                                                         H unas as dibenzothiopheno.

 Hence,  it is supposed that  much of  .the  organosulfur in coal is in such


 thiophenic  structures.   Though chemistry is  known which  can remove


 sulfur from these structures,  it tends  to  be drastic.  Hydrogenation


 for example,  does accomplish  this,  but  only  by adding  sufficient  h  d


 to liquefy  the coal. Oxidation,  followed by  basic hydrolysis  at ele


 temperacure,  can effectively remove sulfur from  dibenzothiophene witho


 further  change.  In the laboratory, using alkali metals as  reductants


 it has been possible to bring  total sulfur levels down to 0.1 percent


     Two principle types of reaction have been used for removal of


organic sulfur - degradative extraction with base (NaOH)  at elevated


temperature and oxidation with concurrent or subsequent hydrolysis
                                   1198

-------
 oxidants which we have heard about are air or oxygen, nitrogen oxides,




 and chlorine. Peroxygen compounds have also been used.  As yet, we know




 little about the chemistry of some of these desulfurization reactions,



 since little model compound work has been done on reactions of this




 type.  It is planned to carry out such studies in the immediate future.




      All of the methods utilized so far have one thing in common.   The



 aaxinun aaounc  of organic sulfur removed is between 40 and 60 percent,




 depending on the coal and reaction conditions.   This seems to be the




 limit approached by the several  methods.   As I  noted previously, this




 could be the result of two types of organic sulfur,  one of which behaves



 chemically like dibenzothiophenic sulfur  and resists most chemical




 treatment.   If  this  is  true, it may not be possible to remove all of the



 organic  sulfur by simple chemical means.




     The prospects for  characterization of  the organic sulfur in coal



 appear good, at least  in .enns of total organic sulfur and some functional



 groups. Practical methods  for removal of up  to half of the organic



 sulfur are at the stage where process development can be undertaken




 provided environmental  acceptance of the product can be guaranteed.




 Consumer demand for  such a product already exists.  Even for those coals




where chemical desulfurization does not provide a product with totally




 acceptable sulfur content, the partial reduction might allow the coal to




 be nixed with a coal of lower sulfur content.  In other situations,  the




 treated coal can be used to lessen the burden placed on the coal consumer




who operates sulfur reducing equipment, such as a flue gas desulfurization




 facility.  In summary,  the prospects are good if there is encouragement




 to proceed.
                                     1199

-------
                          PANEL DISCUSSION ON
                     THE USE OF MODEL ORGANOSULFUR
               COMPOUNDS TO INVESTIGATE THE EFFECTIVENESS
                      OF OXYDESULFURIZATION OF COAL

                T. G. Squires, J. M. Harris, W. F. Goure,
             S. K. Hoekman, B. A. Hodgson, and T. J. Barton
                             Ames Laboratory
                          Iowa State University
                               Ames, Iowa
     Although some progress has been made in  determining  the nature  of
organosulfur components in coal, there is still  very little information
detailing the identity or even the functional group distribution of  these
sulfur moieties.  Specific organosulfur compounds such as thiophenes and
dibenzothiophenes have been isolated from coal and identified. Typically,
these materials were identified as an  incidental consequence of investiga-
ting other types of compounds  in coal. Efforts have also been made to de-
lineate the organosulfur functional group distribution through chemical
and physical properties. The chemical  and physical bases for  these studies
were, at best, obscure and  the results were,  in most cases,  inconclu-
sive.  Investigations are underway  In  this laboratory and at other locations
to detect organosulfur species directly  by using  such  techniques as
3*S NMR and  ESCA. However,  none of these efforts  have  unambiguously
established  the organosulfur  functional  group distribution in coal.
     During  the  initial  phases of  this Investigation,  it has been our
approach  that a definitive knowledge of  the  organosulfur functional  group
distribution is not  a  prerequisite for investigating the viability  of
various desulfurl ration  schemes.  Thus to evaluate a specific desulfurl-
zation process,  It  is  sufficient  to measure  the propensity of a repre-
sentative spectrum  of  organosulfur model compounds toward  desulfurIzation
under  the specific  process conditions.
                                    1200

-------
       Although our conclusions necessarily extend to other oxydesulfur-
   izatton processes, the basis for our initial investigations has been the
  Ames version of the oxydesulfurization process. Conceptually, oxydesul-
  furlzatfon is a two-step process and can be described by the following
  chemical equations:

       Step 1.   Oxidation
  Reaction Conditions:  150°C,  200 ps i  02>  0.2 M aq.  Na2CO-,  1  hour.
      Step 2.  Desul fur ization
               R1
                                                      NaHSO.
      While there is some precedent in the literature for the oxidation
 of sulfides by molecular oxygen,  the basis for Step 2 occurring under
 these reaction conditions is rather tenuous.  Furthermore it is important
 to realize that the sulfur  is not extruded from the organosulfur moiety
 until  the second step.  Thus,  complete conversion of the organic sulfide
 in Step 1  does not  constitute desulfurization.
      The following  organosulfur compounds  have  been subjected  to Ames
 process conditions  (150°C,  200 psi  02> 0.2 M  aqueous Na.CO^,  1  hour)  to
 afford  the results  indicated.
1.
95% Recovery of
starting material
2.
98% (63%*) Recovery
of starting material
                                   1201

-------
 3.
 89% Recovery of s
 starting material
               SCrL
                                              90% (5^/o*)  Recovery
                                              of starting material
 5.
              CH2SCrL
 6.
 82% Recovery of
starting material
                                                   S—S
                                              No other products  detected.
 * 25 grams raw coal  added
      In each of the first five cases,  no oxidation  products were  detected.
      While these are preliminary results and we  are still  refining our
 experimental  techniques,  we  are reasonably certain  that  the first five
 compounds  do not react  under Ames  conditions,  even  in  the  presence of
 raw coal.  We believe that the reduced  recoveries of starting material  in
 the presence of raw  coal  (results  2 and  4)  reflect  adsorption of  the or-
 ganosulfur into the  microporous  surface  of  the coal and mechanical loss
 associated with working up the reaction  mixture.  We are in the process
 of  modifying  our experimental  technique  to obviate  these analytical  prob-
 lems.
      In the case of  thiophenol  (result 6), 70% of the starting material
 can be accounted  for as the  simple disulfidic oxidative coupling product.
Although we have  not accounted for the remaining 30% of the starting
material,  the  initial product of the reaction,  diphenyl disulfide, appears
to be stable under Ames process conditions and is not efficiently oxidized
to benzene sulfonic acid.   Therefore it  is our preliminary  conclusion
that, under oxvdesulfurIzatlon process conditions,  most if  not all organo-
sulfur compounds are unreactiveI
                                  1202

-------
     Another of our primary Initial objectives was to develop catalysts
and reaction conditions for the efficient conversion of organic sulfides
to the oxidized product (Step 1 of the Ames process) using moderate tem-
peratures and atmospheric pressure.  Thus far, we have been able to ef-
ficiently oxidize dlbehzothlophene, phenyl sulfide, and diphenyl disulflde
under the following conditions.
1.
                           1.5 ml  t-BuOOH
                             50 ml PhCH,
                                100°C  *
 2.
                            1.5 ml  t-BuOOH .
                             50 ml  PhCH,  '
                         3 mg Mo(CO)6,  100°C
 3.
     02  stream,  75  C
      10  ml  cumene
        kQ ml  PhCH3
      2.5  mg  Mo(CO)6
                       11.6 min.
                          36 min.
 5.
      Reaction Conditions:  3.1  ml t-BuOOH, 50 ml  PhCHj, 6 mg Mo(CO)6>  75°C
           SS
23 min.'
 75AC
SS

 2

12.^ min.
100° C
                                                                     SO H
      Reaction Conditions: 13 ml t-BuOOH, 50 ml PhCH.,12 mg Mo(CO)6
                                     1203

-------
     On the basis of our experiments,  we have reached  the  following  con-
clusions.
     1.  Organic sulfides can be effectively oxidized  to the sulfones by
         alkyl hydroperoxides in organic solvents.
     2.  In the absence of added hydroperoxide, these same sulfides can
         be oxidized just  as effectively by  bubbling a  stream of oxygen
          through the organic solvent  provided  a substance such as cumene
         or tetralin is present.   These substances  are  known to readily
          form hydroperoxides in the presence of oxygen, and  thus they
          provide a method for the \jn situ  generation  of hydroperoxides.
      3.  The rates of both the molecular oxygen  and hydroperoxide  oxi-
          dations can be increased by a factor of 10 to 15 by the  addi-
          tion of Mo(CO)^.
      k.  Mo(CO)6 is not an effective oxidation catalyst in aqueous media
          and we are unable  to oxidize organic sulfides under aqueous
          conditions even at  high  temperatures and  long reaction times.
      We are  presently  expanding our  initial studies of Mo(CO)x catalysis
  to  other  types  of  organosulfur compounds.   In addition we are evaluating
  catalysts  and  techniques  for achieving oxidation under aqueous conditions,
  and we are investigating  techniques  for grafting these catalysts  to a
  polymer support.
       Our  initial  investigations  of desulfurization (Step 2  of  the oxyde-
  sulfurization process) have been much less encouraging.   During  these
  studies we have generated results which can be  outlined  as follows:
                 DESULFONATION REACTIONS OF MODEL COMPOUNDS
                          0.2M Na2C03
                         80% V/V EG;H20
                             130°C
                                           20_Hours
27 Hours
                                            23 Hours.
                                                         No Reaction
              No Reaction
                                                          No Reaction
                                    1204

-------
                         0.2M NaOH
                          or KOH
                         EG, 190UC
                                     21  Hours (NaOH)
                                                         No Reaction
                                     17 Hours (KOH)
                                        Hours  (NaOH)     No Reaction
                                    22i Hours  (KOH)
                                 0.4M NaOH
                                    H20
                               225°C, 20 Hours
                                               ->•  No Reaction
8.
9.
                               5  Equivs  NaOH
                               0.16  Eq  Bu^NBr
                               1:1 Mesit-H20
                               98°C,  24  Hours
                                  5 Equivs KOH
                                0.2 Eq l8-Crown-6
1.1 Mesit-H20
98°C, 21 Hours
                                   5 Equivs KOH
                                0.25 Eq l8-Crown-6
     Benzene
Reflux 20 Hours
                                                     -^  No Reaction
                                                          No Reaction
                                                          No Reaction
                                 1205

-------
10.
11.
                                   2M
                                150°C, 5 Hours
                                 1 :1 H2SO^-H20
                                145 C, 19 Hours
                                                      No Reaction
                                                      No Reaction
12.
13.
                                  Mesitylene
                                163°, 19 Hours
                                  Mesitylene
                               0.25 Eq l8-Crown-6
                                  163°C, 8 Hours
                                          Unidentified  Isomer
                                          of Starting Material
                                                 60%
                              5 Equiv KOH,  163 C
                                  Mesitylene

                            0.25 Equiv l8-Crown-6
                                   82 Hours
                                            40% Starting
                                            Material
15.
O
  5 Equiv KOH, 163 C
      Mesitylene

0.25 Equiv 18-Crown-6
       48 Hours
Mixture of
Compounds
                               1206

-------
Reactions 1-6 represent increasingly rigorous reaction conditions in an
attempt to achieve desulfurization while working within the scope of the
Ames process.  Even at 225°C for 20 hours, no reaction had occurred.  Re-
actions 7-9 represent attempts to facilitate the reaction through the use
of phase transfer reagents.  This unsuccessful approach was based on the
premise that a homogeneous reaction will proceed more rapidly than a heter-
ogeneous reaction.  On the basis of reactions 10 and 11, it appears that
the reaction cannot be effected in strong acid media either.  Reactions
12-15 represent the only partially successful attempts at desulfonation.
It appears that the rate of the reaction can be substantially increased
by solublizing the KOH with crown ether.  However, even under these re-
action conditions, the rates are very slow; and these conditions do not
represent a viable method for desulfonation.  Presently we are studying
the effects of higher temperatures and catalysts on this reaction.
                                    1207

-------
                             LIST OF PARTICIPANTS
David R. Alison
Arthur D. Little, Inc.
20 Acorn Park
Cambridge MA  02140
864-5770

Robert J. Alison
Mgr. Proj. Dev.
Dravo Corp.
Research Ctr.
Neville Island
Pittsburgh PA  15225
(412) 771-1200 X585

Gerald Anderson
Research Sup.
Inst. of Gas Tech.
3425 S. Stall St.
Chicago IL  60616
(312) 567-5832

Richard J. Anderson
Consultant
3820 Woodbridge Rd.
Columbus OH  43201

Susan Armstrong
Battelle
505 King Avenue
Columbus OH  43201

Dr. Richard Atkins
Mgr., Special Products
Research Cottrell
P.O. Box 750
Bound Brook NJ  08805
(201) 885-7135

Amir Attar, Prof.
University of Houston
Dept.  of Chem.  Eng.
Univ.  of Houston
Houston TX  77004
(713)  749-4965

C. C.  Bailie
Vice Pres., Engineering
Old Ben Coal Co.
500 N.  DuQuoin St.
Benton IL  62812
(618)  435-8176
Dr. L. H. Beckberger
Mgr., Contract R&D
Atlantic Richfield Co.
400 E. Sibley Blvd.
Harvey IL  60426
(312) 333-3000

James E. Benson
Associate Chemist
Ames Lab
Iowa State Univ.
Ames IA  50010
(515) 292-3541

David H. Birlingmair
Head, Coal Prep. Engg.
Ames Laboratory
Iowa State Univ.
Ames IA  50010
(515) 294-2320

J. H. Blake
Mgr., Process Eqpt. Lab
FMC Corp.
1184 Coleman Ave.
Santa Clara CA  95052
(408) 289-2788

Lester E. Bohl
Special Proj. Eng.
PPG Ind.
New Martinsville WV  26155
(304) 455-2200

Charles M. Bonner
Prep. Eng.
C&K Coal Co.
P.O. Box 69
Clarion PA  16214
(814) 226-6911

Sidney Bourgeois
Lockheed
P.O. Box 1103
W. Station
Huntsville AL   35807
(205) 837-1800

Ray Bramhall
Asst. Dir., Prog. Dev.
SRI Int'l
1611 N. Kent St.
Arlington VA  22209
(703) 524-2053, X416
C. Thomas Breuer
Power Supply Staff Eng.
Georgia Power Co.
P.O. Box 4545
Atlanta GA  30302
(404) 522-6060, X3853

Donald R. Brockwehl
Norflor Const. Corp.
2510 E. Jackson St.
Orlando FL  32803
(305) 894-9731

J. Alfred Brothers
Mgr., Chemistry Div.
Nova Scotia Res.
  Foundation Corp.
P.O. Box 790
Dartmouth, Nova Scotia
Canada B2Y 3Z7
(902) 424-8670, X131

Richard A. Brown
Res. Chemist
FMC Corp.
P.O. Box 8
Princeton NJ  07540
(609) 452-2300

Eugene Burns
Prog. Mgr.
Systems, Science &
  Software
Box 1620
LaJolla CA  92037
(714) 453-0060

F. G. Campau
Sup., Mat. Prop. & App.
Detroit Edison Co.
200 Second Ave., H-9, WSC
Detroit MI  48226
(313) 897-1393

Peter Carney
Homer City Gen. Sta.
N.Y. State Elec. & Gas Co.
Homer City, PA  15748
(412) 479-9011
                                        1208

-------
 C.  Blaine Cecil
 Geologist
 U.S.  Geological Survey
 M.S.  956 Geological Surv.
 Nat'l Ctr.
Reston, VA  22092
 (703) 860-7734

 Chandrasekhar
 Foster Miller Assoc.
 Project Mgt.
 135 2nd Avenue
 Walthain MA  02154
 (617) 890-3200

 Christopher Cheh
 Ontario Hydro
 800 Kipling Avenue
 Toronto, Ontario
 Canada M8Z  534

 Kang-Chun Chuang
 Res. Asst.
 Ames Lab.
 Iowa State  Univ.
 305 Sweeney Hall
 Ames IA   50010
 (515)  294-3716

 Or. William E. Clark
 Proj. Mgr.
 Conoco Coal Devi. Co.
 Research  Div.
 Library PA  15129
 835-6605

 Kenneth L.  Clifford
 Mgr.,  Coal  Cleaning
 Electric  Power Res.  Inst.
 3412 Hillview Avenue
 Palo  Alto CA   04303
 (415)  855-2441

 T.J.  dough
 Mgr.,  Major'Pro;).
 Atlantic  Richfield  Co.
 400  E.  Sibley Blvd. ..
 Harvey IL  60426
  (312)  333-3000
Robert L. Cofer
Researcher
Battelle
505 King Avenue
Columbus OH  43201
(614) 424-4441

Dr. M. Cohen
Dir. New Bus. Devel.
Apollo Chem. Conf.
35 S. Jefferson Rd.
Whippany NJ  07981

Randy M. Cole
Proj. Mgr.
TVA
440 Commerce Union  Bank  Bldg.
Chattan-oga TN  37401
(615) 755-3571

Barney W. Cornaby
Ass. Mgr.
Battelle
505 King Avenue
Columbus OH  43201
(614) 424-7572

Martial  P. Corriveau
Vice Pres.
Paul Weir Co.
20 N. Wacker Dr.
Chicago  IL   60606
 (312)  346-0275

Martial  P. Corriveau
Vice Pres.
Paul Weir Co.
20 N. Wacker Dr.
Chicago, IL  60606
(312) 346-0275

Randy Craig
Sverdrup/Birtley Eng,
701 Deseret PI.
15  E. 1st St.
Salt Lake City, IT   84111
(801) 531-7172
Michael M. Crow
Prog. Dev. Coord.
Ames Laboratory
Iowa State Univ.
319 Speddlng Hall
Ames, IA  50010
(515) 294-3758

Peter Cukor
Teknekron, Inc.
2118 Milvia St.
Berkeley, CA  94704
(415) 548-4100

Dr. Rabinder S. Datta
Res. Eng.
Gulf Res. & Dev. Co.
P. 0. Box 2038
Pittsburgh, PA  15230
(412) 362-1600, X2503

R. S. Davidson
Mgr., Env. Ass. Prog.
Battelle
505 King Ave.
Columbus, OH  43201
(614) 424-7646

C. K. Dawson
Sup. Design Eng,
Ontario Hydro
700 Univ."Ave.
Toronto, Canada M5G1X6
(416) 592-5207

W. H. Delany, Jr.
Sales Mgr., Coal
Davy Powergas Corp.
P. 0. Drawer 5000
Lakeland, FL   33803
(813) 646-7459

John J. Detnchalk
Reclam. & Energy Adv.
Appalachian Reg. Comm.
1666 Connecticut Ave., NW
Washington, D.C.  20235
(202) 673-7861
                                         1209

-------
 Peter A.  DeWitt
 Vice  Pres.
 Reiss Viking Corp.
 P.  0.  Box 688
 Sheboygan,  WI  53081
 (ALA)  A57-AA11

 Edward Dismukes
 Southern  Research  Inst.
 2005  Ninth  Ave., S.
 Birmingham,  AL   35205
 (205)  323-6592

 Donald R. Dougan
 Proj.  Eng.
 Babcock & Wilcox Co.
 20  S.  Van Buren Ave.
 Barberton,  OH AA203
 (215)  753-A511

 Cyril  W.  Draffin
 Fossil Energy Planning
 U.S.  DOE
 20  Massachusetts Ave., NW
 Room  422A
 Washington,  D.C.   20003
 (202)  376-A77A

 Ronald Ellis
 Chemist
 Energy &  Min. Res. Co.
 P.  0.  Box A09
 517 Schoolhouse Rd. & U.S.  1
 Kennett Square, PA  193A8
 (215)  AAA-0552

 George  Engelke
 Asst.  Mgr.
 Comm.  Test. & Eng.  Co.
 P. 0.  Box 909
 Rt. 50  East
 Clarksburg, WV  26301
 (304)  623-3329

Michael Epstein
Proj. Mgr.
Bechtel Corp.
P. 0. Box 3965
San Francisco, CA  9A119
 (A15)  768-A16A
 Nicholas T.  F.sposito
 Proj.  Mgr.
 Gen.  Pub.  Ut .  Serv.  Corp.
 260 Cherry  Hill Rd.
 Parsippany,  NJ  07054
 (201)  263-4900

 Glenn  Eurick
 Envir.  Eng.
 MN Power &  Light  Co.
 30 W.  Superior
 Duluth,  MN   55802
 (218)  722-26A1

 R.  A.  Ewing
 Sen. Res. Eng.
 Battelle
 505 King Avenue
 Columbus, OH  43201
 (61A)  A24-4720

 Velmer A. Fassel
 Deputy Director
 Ames Laboratory
 Iowa State University
 Ames,  IA 50011
 (515)  294-3758

 Bobby P. Faulkner, Mgr.
 Allis-Chalmers  Corp.
 P.  0. Box 512
 Milwaukee, WI   53202
 (A14) 475-4624

 Francis  A. Ferraro
 Engineer
 American Electric Power
 P.  0. Box 487
 Canton,  OH   44701
 (216) 452-5721

 Faith Fiene
 Geologist
 111. State Geol.  Survey
 221 Natural  Res.  Bldg.
 Urbana,  IL   61801
 (217) 344-1481

 Karel Fisher
 Teknekron, Inc.
 2118 Milvia  St.
Berkeley, CA  94704
 (415)  548-4100
 Rav W.  Fisher
 Fossil  Eng.  Prog.  Mr.
 Ames Laboratory
 Iowa State  Univ.
 Ames,  IA  50010
 (515)  294-3756

 Carl Flegal
 Applic.  Mer.
 TRW
 01/1050  One  Space  Park
 Redondo  Beach,  CA   90066
 (213)  536-3542

 Donald K. Fleming
 Asso. Dir.
 Institute of  Gas Tech.
 3424 S.  State St.
 Chicago, IL   60616
 (312) 567-3739

 Dr.  Robert A. Florentine
 Adv. Tech. Anal.
 Energy & Min. Res.  Co.
 P.  0. Box 409
 517  Schoolhouse Rd. & U.S.
 Kennett  Square, PA  19348
 (215) 444-0552

 Charles T. Ford
 Sup., Anal. Serv.
 Bituminous Coal Res. Inc.
 350  Hochberg Rd.
 Monroeville, PA  15146
 (412) 327-1600

 Ross Forney
 Dir., Coal Serv. Div.
 Ebasco Services, Inc.
 P. 0. Box 986
 Golden, CO  80401
 (303) 279-8013

 Joyce Fowler
 FPA-IERL
 MD-60
 RTP, NC  27711
 (919) 541-2903

 Roger Frank
 Fuel. Eng.
AMAX Coal Company
 105 S.  Meridian
 Indianapolis, IN  46225
                                         1210

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Dr. Wilfred L. Freyburger
Director
Institute of Mineral Res.
Michigan Tech. Univ.
Houghton, MI  49931
(906) 487-2600

Sidney Friedman
Branch Chief
Pittsburgh Env. Tech. Ctr.
4800 Forbes Ave.
Pittsburgh, PA  15213
(412) 892-2400

John Ganz
Service Rep.
McNally Pitts. Mfg. Corp.
E. Tenth St.
Wellston, OH  45692
(614) 384-2181

Thomas J. George
Mech. Eng., Proc. Env.
Dept. of Eng.
209 Prairie Ave.
P. 0. Box 863
Morgantown, WV  26505
(304) 599-7120

Richard A. Giberti
Kennecott Copper Corp.
128 Spring St.
Lexington, MA  02173
(617) 862-8268

Roland Glenn, Pres.
Combustion Processes
50 E. 41st St.
New York, NY  10017
(212) 889-0255

D. N. Goens
Proj. Mgr.
Hazen Res. Inc.
4601 Indiana St.
Golden, CO  80401
(303) 279-4501
Fred Goodman
Sen. Res. Sci.
Battelle
505 King Avenue
Columbus, OH  43201
(614) 424-7711

Don Grabowski
Sen. Chem. Eng.
CM Corp., Mfg. Staff
GM Technical Ctr.
Warren, MI  48090
(313) 575-1022

James A. Gray
U.S. DOE - PETC
4800 Forbes Ave.
Pittsburgh, PA  15213
(412) 892-2400

Kenneth M. Grav
Homer City Gen. Sta.
PA Electric Co.
Homer City, PA  15748
(412) 479-9011

Jack Greene
Adra. Officer
EPA-IERL
MD-61
RTP, NC  27711
(919) 541-2903

Charles Grua
Div. of Env. Contr. Tech.
U.S. DOE
Washington, D.C.  20545
(301) 353-5516

Robert P. Guerre
Staff Eng.
Exxon Research
P. 0. Box 4255
Baytown, TX  77520

James B. Gulliford
Asst. Ecologist
Ames Laboratory
Iowa State Univ.
Ames, IA  5001]
(515) 294-3756
Edward U. Gunther
Oual. Cont .  Spec.
So. Co. Services
P. 0. Box 2625
Birmingham,  AL  35202
(205) 870-6625

Eugene D. Guth
Chief Chemist
KVB, Inc.
17332 Irvine Blvd.
Tustin, CA  92667
(714) 832-9020

Elton H. Hall
Sen. Chemist
Battelle
505 King Avenue
Columbus, OH  43201
      424-4612
Robert P. Hangebrauck
Dir . , Energy Ass .  &
  Control Div.
EPA-IERL
MD-61
RTP,  NC  27711
(919) 541-2825

H. Shafick Hanna
Asso. Res. Prof.
Mineral Resources Inst,
Univ. of Alabama
P. 0. Box AY
University, AL  354fi6
(205) 348-5453

Donald F. Hardesty
Research Engineer
Shell Development Co.
P. 0. Box 1380
Houston, TX  77001
(713) 493-7871

Warren Hardy
Project Manager
Davy  Powergass , Inc.
P. 0. Box 36444
Houston, TX  77036
(713) 782-3440
                                       1211

-------
Kenneth E. Harrison
Manager - Systems
Heyl & Patterson
Seven Parkway Center
Pittsburgh, PA  15220
(412) 941-5928

Andrew C. Harvey
Project Engineer
Foster-Miller Asso.
135 Second Ave.
Waltham, MA  02154
(617) 890-3200

Donald Haufknecht, Mgr.
Energy Env. Sys. Div.
Science Application, Inc.
1801 Avenue of the Stars
Los Angeles, CA  90067
(213) 553-2705

Roy J. Helfinstine
Mechanical Engineer
111. St. Geol. Survey
Natural Resources Bldg.
Urbana, IL  61801
(312) 344-1481  X 281

William A. Hills
Sr. Res. Chemist
FMC Corporation
P. 0. Box 8
Princeton, NY  08540
(609) 452-2300

Eugene C. Hise
Engineer
Oak Ridge Ntl. Lab.
Bldg. 9204-1
P. 0. Box Y
Oak Ridge, TN  37830
(615) 483-8611 X 3-5619

John A. Hoagland, Mgr.
So. Div.
Commercial Testing
  & Eng. Co.
216 Oxmoor Circle
Birmingham, AL  35209
(205) 942-3120
David C. Hoffman
Supv.-Proc. Dev.
Dravo Lime Co.
650 Smithfield St.
Pittsburgh, PA  15222
(412) 566-4440

Lawrence Hoffman
President
Hoffman-Muntner Corp.
8750 Georgia Ave.
Suite E-134
Silver Spring, MD  20910
(301) 585-6080

Rudols A. Honkala
Physical Scientist
U.S. DOE
Rm. 3449 Fed. Bldg.
Washington, D.C.  20461
(202) 566-9033/9058

George C. Hsu
Group Leader
Jet Propulsion Lab.
4800 Oak Grove Drive
Pasadena, CA  91103
(213) 354-7428

Richard E. Hucko
Civil Engineer
U.S. DOE
4800 Forbes Ave.
Pittsburgh, PA  15213
(412) 892-2400/147

Horst Huettenhain
Mgr., Coal Res. Devel.
Bechtel National, Inc.
P. 0. Box 3965
San Francisco, CA  94119
(415) 768-8039

Robert D. Igou
Researcher
Battelle
505 King Avenue
Columbus, OH  43201
(614) 424-6574
Gerald A. Isaacs
Proj.  Dtr.
PEDCo Environmental, Inc.
P. 0.  Box 20337
Dallas, TX  75220
(214)  259-3577

Robert A. Jacobson
Prof,  of Chemistry
Ames Laboratory - DOE
Iowa State Univ.
Ames,  IA  50010
(515)  294-1144

T. Kelley Janes
Branch Chief
EPA-IERL
MD-60
RTP, NC  27711
(919)  541-2851

Norbert A. Jaworski
Deputy Dtr., IERL/RTP
EPA-IERL
MD-60
RTP, NC  27711
(919)  541-2821

D. M.  Jewell
Sr. Res. Chemist
Gulf RM) Co.
P. 0.  Drawer 2038
Pittsburgh, PA  15230
(412)  362-1600

Robert M. Jimeson
Energy & Env. Consultant
RMJ Associates
1501 Gingerwood Ctt.
Vienna, VA  22180
(703)  281-6555, 6333

John E. Jones, Jr.
Program Manager
Oak Ridge Ntl. Lab.
P. 0.  Box Y
Oak Rigde, TN  37830
(615)  483-8611/37683
                                      1212

-------
W. M. Kaas
President
Komiine-Snaderson Eng. Corp.
Holland Avenue
Peapack, NJ  07977
(201) 234-1000

John J. Kalvinskas
Proj. Mgr./Coal Desul.
Jet Propulsion Lab
4800 Oak Grove Dr.
Pasadena, CA  91103
(213) 354-2349

Frederick V. Karlson
Proj. Eng.
Bechtel Corp.
P. 0. Box  3965
San  Francisco, CA  94119
(415) 768-5838

David R.  Kelland
Co-Group  Leader
MIT  - Francis  Bitter
   Ntl.  Maguet  Lab
NW14-3113
Cambridge,  MA  02139
 (617)  253-5550

 Douglas V.  Kellee, Jr.
 Otisca Industries, Ltd.
 P. 0.  Box 186
 La Fayette, NY 13084
 (315)  475-5543

 Daniel W. Kestner
 Sr. Supporting Devel. Eng.
 AIME CIM
  3600 Neville Rd.
  Pittsburgh, PA   15225
  (412)  771-1200-2251

  James  D. Kilgroe
  Mgr.,  Coal Clng. Prog.
  EPA-IERL
  MD-60
  RTP, NC   27711
  (919)  541-2851

  James  K.  Kindig, Mgr.
  Coal Activities
  Hazen  Research,  Inc.
  4601  Indiana  St.
  Golden,  CO  80401
  (303)  279-4501
David Kirchgessner
Project Officer
EPA-IERL
MD-61
RTP, NC  27711
(919) 541-2851

Dan Kiser
Energy & Env, Anal.
1111 North 19th St.
Arlington, VA  22209
(703) 528-1900

Jeffrey Knight
Mgr. of Preparation
Rochester &  Pitts-
  burgh Coal  Co.
Box 729
Indiana, PA   15701
(412)  465-5621

V.  V.  Kochetov
Operations  Dtr.
Donetsk  Coal Enrichmt.
   Directorate
USSR Ministry of  Coal
Moscow,  U.S.S.R.

 D.  Carroll  Laird, III
 Dow Chemical U.S.A.
 Resources Research
 Texas Div.
 A-2301 Bldg.
 Freeport, TX  77541
 (713) 238-0305

 Alexis W. Letmnon, Jr.
 Deputy Program Mgr.
 Battelle
 *)05 King Avenue
 Columbus, OH  43201
 (614) 424-4472

 Richard Livingston
 Asst. to Asst. Admin.
 EPA
 401 M Street,  S.W.
 MD-RD-672
 Washington, D.D.  20460
  (202)  755-0655
Gregory Lizak
Sen. Business Anal.
FMC Corp.
Central Eng. Labs
1185 Coleman Ave.
Box 580
Santa Clara, CA  95052
(408) 289-2067

Clive Longden
CONCOL, Inc.
Suite 2B
2311 E. Stadium Blvd.
Ann Arbor, MI  48104

Harold L. Lovell
Prof., Mineral Eng.
PA  State  Univ.
121 Mineral  Sci. Bldg.
University  Park, PA   16802
(814)  863-1641

Basil  Lukianoff
Whiper Interpreting
 15 Hillside St.
 Danbury, CT  06810
 (203)  743-4884

 A. L.  Luttrell,  Mgr.
 Adv. Ping.  & Mktg.
 Sverdrup/ARO, Inc.
 101 W. Lincoln St.
 P. 0.  Box 884
 Tullahoma,  IN  37388
 (615)  455-1186

 F. Monty Lyon
 Div. Prep.  Eng.
 Republic Steel Corp.
 Fayette  Bank Bldg.
 Uniontown,  PA   15401
  (412)  438-2587

 Richard  Markuszewski
 Research Asso.
 Ames  Laboratory
  Iowa  State Univ.
 Ames,  IA  50011
  (515)  294-6374
                                         1213

-------
Lee C. McCandless
Operations Mgr.
Versar,  Inc.
6621 Electronic Dr.
Springfield, VA  22151
(703) 750-3000

William  N. McCarthy, Jr.
Chemical Engineer
EPA
10813 Vista Road
Simpsonville, MD  21044
(301) 531-6256

Jane McCreery
Battelle
505 King Avenue
Columbus, OH  43201
(614) 424-7992

Ray MeGraw
Staff Supv. Coal Prep.
Homer City Gen. Sta.
Homer City, PA  15748
(412) 479-9011

Edward T. McNally
Chairman
McNally Pittsburg Mgf. Co.
P. 0. Box 651
Pittsburg, KS  66762
(316) 231-3000

Aubrey F. Messing
Research Asso.
Empire St. Elec. Energy
  Res. Corp., Suite 3950
1271 Avenue of the Americas
New York, NY  10020
(212) 246-4300

R. A.  Meyers
Project Mgr.
TRW, Inc.
1  Space Park
Redondo Beach, CA  90278
(213)  536-2734

Eugene J. Mezey
Chemist
Battelle
505 King Avenue
Columbus, OH  43201
(614)  424-4995
Nick Milicia
Lab. Field Eng.
Joy Manufacturing
1755 Blake St.
Denver, CO  80202
(303) 892-0073

Rebecca Miller
Battelle
505 King Avenue
Columbus, OH  43201
(614) 424-4471

Michael Ray Miller
Asst. Eng.
Ames Laboratory
Iowa State Univ.
Ames, IA  50010
(515) 294-7508

Michael W. Miller
Sales Mgr.
Parkson Corp.
5601 NE 14 Ave.
Ft. Lauderdale, FL  33307
(305) 772-6860

Claude M. Moreland
Proj. Mgr.
Kaiser Engineers
P. 0. Box 23210
Oakland, CA  94623
(415) 271-5291

Michael P. Morrell
Engineer
GPU Service Corp.
260 Cherry Hill Rd.
Parsipanny, NJ  07054
(201) 263-4900/200

William F. Musiol, Jr.
Asso. Process Eng.
Dravo Corporation
17th Floor
One Oliver Plaza
Pittsburgh, PA  15222
(412) 566-3386

Kenneth R. Musolf
Plant Manager
Reiss Viking Corp.
2215 Breezeview
Bluefield, WV 24701
(304) 327-7639
I. K. Nekharoshy
Head of Laboratory
Inst. for Enrichmt.
  of Solid Fuel
USSR Ministry of Coal
Moscow, U.S.S.R.

Gerry Norton
President
Norton-Hambleton Asso. Inc.
Suite 2B
2311 E. Stadium Blvd.
Ann Arbor, MI  48104
(313) 995-4044

Barry M. O'Brien
Product Manager
Exxon Chem. Co. USA
P. 0. Box 3272
Houston, TX  77001
(713) 656-0240

Robin R. Oder
Research Asso.
Gulf R&D Corp.
P. 0. Drawer 2038
Pittsburgh, PA  15230
(412) 362-1600/2953

Keith M. Parker
Env. Sci.
Wisconsin Power & Light
222 W. Washington Ave.
Madison, WI  53703
(608) 252-3084

R. C. Patyrak
Proj. Mgr.
Tennessee Valley Auth.
Water Oual. & Eco.
401 Chestnut
Chattanooga, TN  37401
(615) 755-3153

T. A. Pearce
Dow Chemical, USA
Texas Div.
A-2303 Bldg.
Freeport, TX  77541

Jaroslaw Pekar
Prog. Coor.
EPA-IERL
MD-62
RTP, NC  27711
(919) 541-2379
                                           1214

-------
 Lucy Pierson
 Battelle
 505 King Avenue
 Columbus, OH  43201
 (614) 424-7816

 Dan A.  Poindexter
 Mine Liaison Agent
 Cols. & So.  Elec. Co.
 215 N.  Front St.
 Columbus, OH  43215
 (614) 464-7296

 Robert  H. Poirier
 Dept. Mgr.
 Battelle
 505 King Avenue
 Columbus, OH  43201
 (614) 424-4815

 Neil W.  Policow
 Sales Eng.
 Bird Machine Co.
 155 Linden Ct.
 Pittsburgh,  PA 15237
 (412) 367-4955

 Clifford R.  Porter
 Proj. Mgr.
 Nedlog  Tech.  Grp.
 12191 Ralston  Rd.
 Arvada,  CO   80004
 (303) 425-5055

 Frank Princiotta
 Dtr., Energy Proc.  Div.
 EPA-OEMI
 631  RD  681
Washington, D.C.   20460
 (202) 755-0205

M. J. Prior
 IEA  Coal  Research
 14/15, Lower Grosvenor PI
London,  S.W.I,  England
London 828-4661

Mark Pritzker .
Phys. Sci.
Canmet
552 Booth St.
Ottawa,  Ontario
Canada K1A OG 1
(613) 992-7782
 James B.  Proske
 Design Eng.
 Brown & Root,  Inc.
 P.  0. Box Three
 Houston,  TX   77001
 (613) 678-9791

 Steve Provol
 Shell Devel.  Co.
 W.  Hollow Res. Ctr.
 TB-214
 P.  0.  Box 1380
 Houston,  TX   77001
 (713)  493-7237

 Leslie Mark Pruce
 (No Address)

 V.  C.  Ouackenbush
 Mgr.,  Business Ping.
 Catalytic, Inc.
 Centre Square  West
 1500  Market Street
 Philadelphia,  PA  19102
 (215)  864-8587

 Gilbert E. Raines
 Raines  Consulting, Inc.
 1016  Amberly Place
 Columbus, OH   43220
 (614)  451-5777

 Kendall B. Randolph
 Sr. Chem. Eng.
 Versar, Inc.
 6621  Electronic Dr.
 Springfield, VA  22151
 (703)   750-3000

 Robert Reeves
 Mining Engineer
 Ebasco Services, Inc.
 P. 0.  Box 986
 Golden, CO  80401
 (303)  279-8013

 David A. Rice
 Engineer
 Bethlehem Steel Corn.
Homer Res. Labs, Bldg. A
Bethlehem, PA  18016
 (215)  694-2196
 Gerald  L.  Robinson
 Sr.  Res.  Sci.
 Battelle
 505  King  Avenue
 Columbus,  OH   43201
 (614) 424-4473

 Sharron F.  Rogers
 Res. Ecologist
 Battelle
 505  King  Avenue
 Columbus,  OH   43201
 (614) 424-7588

 John M. Rosenbaum
 Research  Asst.
 Univ. of  CA, Berkeley
 4576 Elmwood Rd.
 El Sobrante, CA  94803
 (415) 222-1928

 E. S. Roth
 Comm. Devel. Mgr.
 FMC  Corporation
 2000 Market St.
 Philadelphia,  PA  19103

 R. L. Rowell
 Asso. Prof.
 Dent, of  Chemistry
 Univ. of MA
 Amherst, MA  01003
 (413) 545-0247

 Salomon M. Salomon
 Sen. Sci.
 Bird Machine Co.
 Neponsset St.
 N. Walpole, MA  12071
 (617) 668-0400

 Robert H.  Salvesen
 Res. Asso.
 Exxon Research & Eng. Co.
 P. 0. Box 8
 Linden,  NJ  07036
 (201) 474-2220

Myrrl J. Santy, Head
Proc. Design Sec.,
  Chem.  Eng. Dept.
TRW Systems
One Space  Park  .
Redondo  Beach, CA  90278
 (213) 536-4076
                                        1215

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 Donald  Sargent
 Operations Mgr.
 Versar,  Inc.
 6621 Electronic Dr.
 Springfield, VA  22030
 (703) 750-3000

 K.  I. Savage
 Res. Dlr.
 Commercial Testing & Eng. Co.
 228 N. La Salle St.
 Chicago, IL  60601
 (312) 726-8434

 James J.- Schaeffer, Jr.
 Heyl & Patterson, Inc.
 No. 7 Parkway Center
 Pittsburgh, PA  15220
 (412) 922-3300/263

 Nell R. Schemehorn
 Staff Geologist
 Northern IN Pub. Serv. Co.
 5265 Hohman Ave.
 Hammond, IN  46325
 (219) 853-5395

 Rudy Schuller
 Research Asso.
 111. St. Geol. Survey
 Univ. of Illinois
 Natural Res. Center
 Urbana, IL  61801
 (217) 333-1197

 Robert G. Shaver
 Vice President
 Versar, Inc.
 6621 Electronic Dr.
 Springfield, VA  22151
 (703) 750-3000

 J. R. Sinek
Mgr., Energy Systems
Kennecott Copper Corp.
128 Spring St.
Lexington,  MA  02173
 (617) 862-8268
Bill  Slaughter
Proj. Mgr.
EPRI
3195  Kipling
Palo  Alto, CA  04303
(415) 855-2441

Donald J. Smalter
Dir.  - Development
Research-Cottrell
P. 0. Box 750
Bound Brook, NJ  08805
(201) 885-7826

Ben Smith
Research Chemist
EPA-IERL
MD-62
RTF,  NC  27711
(919) 541-2557

Clay  D. Smith
President
Otisca Industries, Ltd.
P. 0. Box 186
La Fayette, NY  13084
(315) 475-5543

G. Ray Smithson, Jr.
Mgr., Env. Control
  Tech. Prog. Office
Battelle
505 King Avenue
Columbus, OH  43201
(614) 424-7814

Robert Smock
Senior Editor
Elec. Light & Power Mag.
1301 S. Grove Ave.
Barrington,  IL  60010
(312) 381-1840

Thomas C. Sorensen
Flotation Mgr.
The Galigher Co.
P. 0. Box 209
Salt Lake City, UT  84110
(801) 359-8731
Thomas G. Squires
Asso. Chemist
Ames Laboratory
Iowa State Univ.
Ames, IA  50010
(515) 294-1836

Edgel P. Stambaugh
Sr. Res. Sci.
Battelle
505 King Avenue
Columbus, OH  43201
(614) 424-7827

Ronald W. Stanton
Geologist
U.S. Geological Survey
956 National Center
Reston, VA  22092
(703) 860-6104

C. W. Statler
Mgr., Generation Fuel Tech.
PA Electric Co.
1001 Broad St.
Johnstown, PA  15907
(814) 536-6611/513

Walter G. Steblez
Interpreter
Whisper Interpreting
15 Hillside St.
Danbury, CT  06810
(203) 743-4884

Richard D. Stern, Chief
Process Tech. Branch
EPA-IERL
MD-61
RTF, NC  27711
(919) 541-2915

John Suloway
Research Asst.
111. St. Geol. Survey
Univ. of IL
Natural Res. Ctr.
Urbana,  IL  61801
(217) 333-1197
                                       1216

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 David Tamny
 Project  Officer
 EPA-IERL
 MD-60
 RTF,  NC   27711
 (919) 541-2851

 Terry W.  Tarkington
 Chemical Eng.
 Tennessee Valley  Auth.
 OS WHA
 Muscle Shoals,  AL  35660
 (205)  383-4631/2516

 Richard  R. Taylor
 Mgr.  Eng.
 FMC Corporation
 MHS Division
 1801  Locust Ave.
 Fairmont,  WV  26554
 (304)  366-6550

 Scott R.  Taylor
 Res.  Chemist
 U.S.  DOE
 4800  Forbes Ave.
 Pittsburgh, PA  15213
 (412)  892-2400/177

 Don Thomas
 Mgr.  Coal  Prep.
 Davy  Powergas Corp.
 P. 0.  Drawer 5000
 Lakeland,  FL  33803
 (813)  646-7459

 Ralph  E. Thomas
 Res.  Leader
 Battelle
 505 King Avenue
 Columbus, OH  43201
 (614)  424-7236

 S. J.  Thomas
Marketing Spec.
Babcock & Wilcox
P. 0. Box 835
Alliance,.OH  44601
 (216) 821-9110
 James H.  Tice
 Eng.  Coor.
 Env.  Qual.  Cont.  Sys.
 PA Electric Co.
 1001  Broad  St.
 Johnstown,  PA  15907
 (814)  536-6611

 Duane A.  Tolle
 Research  Ecologist
 Battelle
 505 King  Avenue
 Columbus, OH 43201
 (614)  424-7591

 Ed Ungar
 Director
 Battelle
 505 King  Avenue
 Columbus, OH 43201
 (614)  424-7369

 Peter  Van Voris
 Task Manager
 Coal Clng.  Prog.
 Battelle
 505 King  Avenue
 Columbus, OH 43201
 (614)  424-7579

 G.  G.  Voznyuk
Head of Directorate
   for  Env.  Control
 USSR Ministry of Coal
Moscow, U.S.S.R.

Daman  S. Walia
Res. Sci.
 IIT Research  Inst.
 10 W.  35th  St.
Chicago,  IL  60616
 (312)  567-4288

Robert P. Warzinski
Chemist
U.S. DOE - PETC
4800 Forbes Ave.
Pittsburgh,  PA  15213
 (412)   842-2400/321
 Margaret A. Wechter
 Sci. Admin./Fossil
   Energy Program
 Ames Laboratory
 Iowa State  Univ.
 Ames,  IA  50010
 (515)  294-3758

 Lawrence P. Weinberger
 Member, Tech. Staff
 The Aerospace Corp.
 20030  Century Blvd.
 Germantown, MD  20767
 (301)  428-2748

 Bernie Weiss, Supv.
 Clean  Energy Tech.
 Catalytic,  Inc.
 1500 Market Street
 Philadelphia, PA  19102
 (215)  864-8591

 Eugene M. Wewerka
 Staff Member
 Los Alamos  Sci. Lab.
 CMB-8, MS-734
 P. 0. Box 1663
 Los Alamos, NM  87545
 (505) 667-5182

 T. D. Wheelock
 Professor
 Iowa State  Univ.
 Ames, IA  50011
 (515) 294-5226

 Richard L. White
 General Mgr.
 Reiss Viking Corp.
 P. 0. Box 3336
 Bristol, TN  37620
 (615) 878-2563

 D. G. Williams
 Vice President
 N. Amer. Mining Cons., Inc,
 1 Penn Plaza
 250 W.  34th  St.
New York,  NY  10001
 (212) 760-2500
                                       1217

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W. M. Wills
Manager - Laurel Run
Laurel Run Mining Co.
P. 0. Box 26343
Richmond, VA  23260
(804) 644-4905

Jack Witz
Member of Tech. Staff
Aerospace Corp.
P. 0. Box 92957
Los Angeles, CA  90007
(213) 643-5372

Samuel Wong
Asst. Chem. Eng.
Argonne Natl. Lab.
Bldg. 205-Cen.
9700 S. Cass AVenue
Argonne, IL  60439
(312) 972-7565

Peter J. Woollam
Vice President
Bateman Coal Eng. Corp.
400 Morris Ave.
Denville, NJ  07834
(201) 625-5300

Harold Young
Asst. Mgr. Govt. Ops.
FMC Corporation
328 Brokaw Road
Santa Clara, CA  95126
(408) 289-2692

Jackson Yu
Project Mgr.
Bechtel Natl., Inc.
50 Beale Street
P. 0. Box 3965
San Francisco, CA  94119
(415) 768-3278

Peter Zavitsanos
Sr. Phys.  Chem.
General Electric
3198 Chestnut  St.
Philadelphia,  PA  19101
(215)  962-3496
                                    1218

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                                TECHNICAL REPORT PATA
                         (Please rtad liutructioni on tht
                                          nvtm Mfort compltHni)
1.REPOBTNO.
 EPA-600/7-79-098b
                          2.
                                                     3. RECIPIENT'S ACCESSION-NO,
4. TITLE AND SUBTITLE
 Proceedings: Symposium on Coal Cleaning to Achieve
  Energy and Environmental Goals  (September 1978,
                                                     5. REPORT DATE
                                                      April 1979
                                                     6. PERFORMING ORGANIZATION CODE
 S.E.Rogers and A.W.Lemmon, Jr. (Editors)
                                                     «. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
 Battelle Columbus Laboratories
 505 King Avenue
 Columbus, Ohio  43201
                                                     10. PROGRAM iLEMlNf NO.
                                                     EHE624A
                                                     11. CONTRACT/GRANT NO.

                                                      68-02-2163, Task 861
 12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 Industrial Environmental Research Laboratory
 Research Triangle Park, NC 27711
                                                                             VERED
                                                     14. SPONSORING AGENCY CODE
                                                       EPA/600/13
15. SUPPLEMENTARY NOTES T£RL.RTpprojectofficerJsJamesD
                                                                , MD-61, 919/541-
US. ABSf RACT	:	——	——
 The proceedings document presentations made at the Symposium on Coal Cleaning to
 Achieve Energy and Environmental Goals, September 11-15,  1978, in Hollywood,
 Florida,  The symposium provided an opportunity for mutual review and discussion
 of: the physical and chemical coal cleaning programs of EPA, DoE, the Electric
 Power Research Institute, and numerous industrial organizations; European and
 Soviet plans for the future; and problems of ongoing operations. The proceedings
 include the following topics: coal characteristics, coal cleaning overview, physical
 coal cleaning technology,  environmental assessment and pollution control technology,
 and chemical coal cleaning technology.  The first three topics are covered in Volume
 I; the last two, in Volume n.
n.
                             KEY WORDS AND DOCUMENT ANALYSIS
                DESCRIPTORS
                                          b. IDENTIFIERS/OPEN ENDED TERMS
                                                                    COS AT I Field/Group
 Pollution
 Coal
 Physical Properties
 Chemical Properties
 Assessments
                                          Pollution Control
                                          Stationary Sources
                                          Coal Cleaning
                                          Environmental Assess-
                                           ment
13B
21D,08G
14B
07D
IB. DISTRIBUTION STATEMENT

 Unlimited
                                          19. SECURITY CLASS (TMtRtport)
                                          Unclassified
21. NO. OF PAGES
    592
                                          20. SECURITY CLASS (Tillspogt)
                                          Unclassified
                                                                  22. PBICE
•PA Perm 2220-1
                                       1219

                   *U.S. GOVERNMENT PRINTING OFFICE: 19 79 -6UO-01* 39 02 REGION NO.*

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