United States Industrial Environmental Research EPA-600/7-79-016
Environmental Protection Laboratory January 1979
Agency Research Triangle Park NC 27711
Evaluation of the Flash
Desulfurization Process
for Coal Cleaning
Interagency
Energy/Environment
R&D Program Report
-------
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.
-------
EPA-600/7-79-016
January 1979
Evaluation of the Flash
Desulfurizafion Process for
Coal Cleaning
by
Donald K. Fleming and Robert D. Smith
Institute of Gas Technology
3424 South State Street
Chicago, Illinois 60616
Contract No. 68-02-2126
ROAP No. 21AFJ-40
Program Element No. 1AB013
EPA Project Officer: Lewis D. Tamny
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
-------
DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and policies of
the U.S. Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
ii
-------
EXECUTIVE SUMMARY
The purpose of this program is to develop, on the laboratory-, bench-, and pilot-
unit scale, the operating conditions for the key steps in the IGT process to desulfurize
coal by chemical and thermal treatment. . ,
Laboratory- and bench-scale data on high-sulfur, Eastern U.S. coals prove that the
process is capable of sufficient sulfur reduction that the resulting solid fossil fuel could
be directly consumed in compliance with current environmental regulations for sulfur
oxide emissions. Because of operating and technical difficulties, the data from the pilot-
unit scale testing are inconclusive. A preliminary economic analysis of a conceptual
process indicates that the treated fuel would have a price of $1.50 to $1.75/miUion Btu
(in 1977 dollars on a utility financing basis) if the initial coal costs $1.00/million Btu.
An oxidative pretreatment of the coal air fluidization of the coal at 750°F for
30 minutes with 1 SCF O^ consumed per pound of dry coal is an integral part of the
system. This pretreatment not only prevents caking in the subsequent fluidized-bed
hydrodesulfurization reaction, it also renders the sulfur in the coal more amenable to
removal.
Four Eastern U.S. coals, from abundant coal seams, were treated under various
reducing-gas atmospheres at elevated temperatures. Sufficient sulfur removal was
achieved from all coals tested at ambient pressure and at temperatures of 1500°F and
residence times of 60 minutes. These data were obtained in laboratory, fixed bed,
continuous weighing reactors and bench-scale, fluidized-bed systems.
As initially conceived, the process incorporated a "sulfur-getter" a material that
has a greater chemical affinity for the sulfur than the coal has. Lime is an example of
such a sulfur-getter. Parallel tests in the laboratory- and bench-scale equipment
indicated that the addition of lime to the coal during hydrotreatment had little apparent
advantage for sulfur removal and significant disadvantages in the recovery of treated
material and the regeneration of the lime. Consequently, the use of the sulfur-getter in
the process was deleted.
Scale-up problems, however, later proved that the sulfur-getter concept was
required in the system. Tests with larger-scale, continuous feeding fluidized-bed
equipment did not result in satisfactory sulfur removal at the operating conditions
determined from the smaller-scale tests. The necessary ratio of hydrogen-to-coal in the
larger units was much lower than in the smaller units; consequently, the hydrogen sulfide
concentration in the fluidizing gas was increased, inhibiting desulfurization. The use of
the sulfur-getter is therefore required to reduce the hydrogen sulfide concentration in
the gas. This discovery was made late in the program and testing of this factor in the
large-scale equipment could not be accomplished within the time and budget constraints.
Thermodynamic, laboratory, and bench-scale data indicate that the concept is sound.
iii
-------
A conceptual process design was developed, based on the process without the
getter addition. Heat and material balances were made. Significant by-product values in
power, intermediate-Btu gas, BTX, and sulfuric acid reduced the price of the desulfur-
ized solid fossil-fuel product to about $l.Z9/million Btu. A process was conceptualized
including iron oxide as a sulfur-getter (based on the contractor's Steam-Iron Process
technology) and, using very conservative processing assumptions in the absence of hard
data, the cost of the treated fuel product was approximated at $1.75/million Btu.
A brief outline for the direction of future work on the process is indicated,
including the construction and operation of a continuous, integrated Process Develop-
ment Unit for proof of the technical viability of the process.
iv
-------
TABLE OF CONTENTS
Executive Summary i i i
List of Figures vi
List of Tables vi i i
Conversion Factors x i
Objective 1
Introduction and Background 2
Coal Preparation 6
Crushing 6
Pretreatment 6
Coal Preparation Conclusions 22
Laboratory-Scale Test Work Hydrodesulfurization 23
Western Kentucky No. 9 Coal 23
Pittsburgh Seam - West Virginia Coal 33
Pittsburgh Seam - Pennsylvania Coal 43
Illinois No. 6 Coal 43
Ef f ec t o f Heat-Up Rate 62
Laboratory-Scale Test Conclusions 7 1
Bench-Scale Test Work Hydrodesulfurization 72
Western Kentucky No. 9 Coal Runs 7 2
Slow Heat-Up Runs 7 2
Rapid Heat-Up Runs 80
Unpretreated Western Kentucky No. 9 Coal 8 0
Siderite Acceptor Runs 90
Nitrogen-Hydrogen Mixtures 90
Hydrogen-Carbon Monoxide-Water Mixtures 9 0
1% H2S in Hydrogen 98
Illinois No. 6 Coal Runs 98
Bench-Scale Test Work - Conclusions 108
10-lhch-Diameter Continuous Fluidized-Bed Test Work - Hydrodesulfurization 109
Results 109
Continuous Runs - Conclusions 114
Nitrogen Emissions for Treated Coals 116
Coal Combustion Methods 123
Economic Studies 126
Process Design Results 126
Process Economics 127
Operating Costs . 127
Product Price Sensitivities 133
Effect of Process Revision to Include "Sulfur-Getter" Loop 133
Economic Studies - Conclusion 134
Process Development Unit (PDU) Requirements 135
Conceptual Design . 135.
Future Work 141
10-hch-Diameter Unit 141
Acceptor Regeneration 141
Process Development Unit 141
-------
LIST OF FIGURES
Number Page
1 Sulfur Removal Indicating Effect of Coal Pretreatment 9
2 Pretreater Flowsheet (Basis: 100 Ib Dry Western
Kentucky No. 9 Coal) 13
3 Pre treated Material Balance, Illinois No. 6 Coal 16
4 Treated Material Sulfur Content, Western
Kentucky No. 9 Coal 3 1
5 Treated Material Recovery, Western Kentucky
No. 9 Coal 3 Z
6 Treated Material Sulfur Content, Pittsburgh Seam,
West Virginia Coal 40
7 Treated Material Recovery, Pittsburgh Seam, West
Virginia Coal 41
8 Treated Material Sulfur Content, Pittsburgh Seam,
Pennsylvania Coal 50
9 Treated Material Recovery, Pittsburgh Seam,
Pennsylvania Goal 5 1
10 Treated Material Sulfur Content, Illinois No. 6 Coal 59
11 Treated Material Recovery, Illinois No. 6 Coal 60
1Z Thermobalance Sample Weight Loss 65
13 Thermobalance Runs, Data on Pretreated
Western Kentucky No. 9 Coal 66
14 Effect of Holding Time on Sulfur Removal 69
15 Treated Material Sulfur Content - Batch Reactor
Tests on Western Kentucky No. 9 Coal 8 1
16 Degree of Sulfur Removal in Batch Reactor Tests
as a Function of Effective Run Time 86
17 Effect of Hydrogen on Sulfur Removal 97
18 Percent of Nitrogen Remaining After Treatment, for
Batch Reactor Tests With Western Kentucky
No. 9 Coal 118
vi
-------
LIST OF FIGURES, Continued
Number Page
19 Coal Desulfurization Process (Western Kentucky
Coal, Feed Rate 20,000 tons/day) 128
20 Pretreatment Section . 139
21 Hydrotreatment Section 137
vii
-------
LIST OF TABLES
Number Page
1 Illinois No. 6 Coal Analyses (Hillsboro Mine) 7
2 Screen Analysis for Crushing Tests 8
3 Typical Analysis of Raw and Pretreated Coal 14
4 Pretreatment of Illinois No. 6 Coal 14
5 Pretreater Material Balance, Illinois No. 6 Coal 17
6 Pretreater Heat Balance (Basis: 77°F, lOOlb Dry Coal) 18
7 Analysis for Pretreatment of Pittsburgh Seam,
West Virginia Coal 20
8 Analysis for Pretreatment of Pittsburgh Seam,
Pennsylvania Coal 21
9 Analyses of Western Kentucky No. 9 Coal 24
10 Thermobalance Test Run Data, Pretreated
Western Kentucky No. 9 Coal 25
11 Calculated SO-y Emissions From Combustion
of Treated Coal 30
12 Analyses of Pittsburgh Seam, West Virginia Coal 34
13 Thermobalance Test Run Data, Pretreated Pittsburgh
Seam, West Virginia Coal 3 5
14 Calculated SO 5 Emissions From Combustion of
Treated Pittsburgh Seam, West Virginia Coal 42
15 Analyses of Pittsburgh Seam, Pennsylvania Coal 44
16 Thermobalance Test Run Data, Pittsburgh Seam,
Pennsylvania Coal 45
17 SO, Emissions for Thermobalance Runs, Pretreated
Pittsburgh Seam, Pennsylvania Coal 5 2
18 Analyses of Illinois No. 6 Coal 53
19 Thermobalance Test Run Data, Illinois No. 6 Coal 54
viii
-------
LIST OF TABLES, Continued
Number Page
20 SO 2 Emissions for Thermobalance Runs, Pretreated
Dlinois No. 6 Coal 6 1
21 Thermobalance Run Data, Pretreated Western
Kentucky No. 9 Coal 63
22 Thermobalance Run Data, Western Kentucky No. 9
Coal (Rapid Heat-Up Rate) 67
23 SO, Emissions and Heating Values for Western Kentucky
- No. 9 Coal (Rapid Heat-Up Rate) 70
24 Analyses of Batch Reactor Runs With Western
Kentucky No. 9 Coal 73
25 Batch Reactor Test Run Data for Pretreated
Western Kentucky No. 9 Coal 74
26 Batch Reactor Test for SO^ Emissions and
Heating Values, Western Kentucky
No. 9 Coal 79
27 Batch Reactor Run Data for Pretreated Western
Kentucky No. 9 Coal 82
28 SO 2 Emissions and Heating Values for Western
Kentucky No. 9 Coal Treated Material 8 7
29 Comparison of Batch Reactor Runs With Pretreated
and Unpre treated Western Kentucky No. 9 Coal 88
30 Batch Reactor Run Data, Western Kentucky
No. 9 Coal With Siderite 9 1
31 Batch Reactor Run Data for Western Kentucky
No. 9 Coal 9 3
32 Pretreated Western Kentucky No. 9 Coal Batch
Reactor Runs With N_-H2 Gas Mixtures 9 5
33 Batch Reactor Run Data 99
34 Comparison of Sulfur Values for H-,
H?-H7SRuns 100
Li Lt
35 Batch Reactor Tests - Pretreated Illinois
No. 6 Coal (-10+40 Mesh) 1 0 1
ix
-------
LIST OF TABLES, Continued
Number Page
36 Batch Reactor Tests - Pretreated Illinois No. 6
Coal (Unscreened) 103
37 Batch Reactor Tests - Pretreated Illinois No. 6
Coal (-10+40 Mesh + Lime) 105
38 SO2 Emissions and Heating Values for Illinois
No. 6 Coal Treated Material 107
39 ' 10-Inch Unit Data - Pretreated Illinois
No. 6 Coal 110
40 Sulfur Species in Nitrogen Run 1 11
41 10-Inch Unit Runs With Pretreated Illinois
No. 6 Coal 112
42 Gas Analysis 113
43 Sulfur Balance for PDS Runs 115
44 Nitrogen Emissions for Batch Reactor Tests,
Western Kentucky No. 9 Coal 117
45 Batch Reactor Test Run Data for Pretreated
Western Kentucky No. 9 Coal 119
46 Capital Investment Summary, Mid-1975 130
47 Annual Operating Cost 131
48 Gas Cost Calculation by Utility Method Used in the
"Final Report of the FPC Supply-Technical Advisory
Task Force - Synthetic Gas-Coal" 132
49 Pretreater Streams 136
50 Hydrotreater Streams 137
51 Pretreater Equipment List 138
52 Hydrotreater Equipment List 140
-------
CONVERSION FACTORS
Non SI Units
atmosphere
Btu
Btu/lb
cal
°C
°F
°F/min
foot
gpm (gallons per minute)
inch
in H20
in H20/ft
pound
psi(a)
SCF/hr
Operation
x 101325
x 1055.87
x 2327.794888
x 4.19002
+ 273.15
(5/9)(TF + 459.67)
x 0.0092593
x 0.3048
x 0.0000630902
x 0.0254
x 249.082
x 2988.98
x 0.45359237
x 6894.7572
x 0.000007865790722
SI Unit
N/m2
J
J/kg
J
K
K
K/s
m
m3/s
m
N/m2
N/m3
kg
N/m2
m3/s
Mesh
An Empirical Measure of Particle Size:
U.S.
Mesh
10
12
14
20
30
40
60
80
100
Opening Size
mm
2.00
1.68
1.41
0.84
0.59
0.42
0.25
0.177
0.149
xi
-------
OBJECTIVE
The objective of the program is to determine experimentally, on laboratory-,
bench-, and pilot-unit scales, the operating conditions for the key steps in the IGT
process to desulfurize coal by thermal and chemical means. The current (early 1978)
Federal EPA New Source Performance Standard. (NSPS) for solid fossil-fuel combustion
has largely been observed by switching to low-sulfur fuels. Achieving the goals of this
program will increase the supply of low-sulfur solid fuels.
-------
INTRODUCTION AND BACKGROUND
This document is the final report under EPA Contract No. 68-02-2126, encom-
passing work on the development of the Flash Desulfurization Process over the period
from November 1975 through October 1977.
Researchers at the Institute of Gas Technology (IGT) have conceived a process for
the removal of sulfur from .coal by a combination of thermal and chemical means: A U.S.
Patent has been granted on this process and assigned to IGT. The objective of the work
described in this report is to develop the key steps of that process.
The process incorporates low-pressure (nearly ambient) treatment of the coal in a
reducing atmosphere at temperatures sufficient to liberate the sulfur in the coal as H^S,
However, the sulfur in the coal is not a distinct chemical species, but exists in many
forms that react with hydrogen at varying temperatures. The program is designed to
evaluate the removal of total sulfur (organic as well as pyritic) from the coal as
functions of operating temperature and reaction time and to determine the severity of
treatment required for the manufacture of an environmentally satisfactory, solid fuel
product.
The initial process concept included adding a "sulfur-acceptor" ("sulfur-getter") to
the coal. The thermodynamic equilibrium concentration of H^S over coal-ash is not high
and the sulfur-getter is defined here as a material that has a greater affinity for the
sulfur than the coal has. One example of such a sulfur-getter is lime: Hydrogen sulfide
has a lower equilibrium partial pressure over lime than it has over coal. Therefore, the
reducing gas will react with the coal-sulfur, forming ^S. The ^S, however, will react
almost instantaneously with the lime. In the overall system, therefore, sulfur is
transferred from the coal to the lime with an HoS intermediate.
The work reported here is a continuation of a program reported earlier under
Contract No. 68-02-1366 entitled, "Pilot Plant Study of Conversion of Coal to Low-Sulfur
Fuel." The summary of that report is presented below as background for this document:
"The purpose of this program is to develop, on a bench and pilot scale,
the operating conditions for the key step in the IGT process to desulfurize
coal by thermal and chemical treatment. This process, to date, uses the
"sulfur-getter" concept. A sulfur-getter is defined as a material that has a
greater, chemical affinity for sulfur than the coal has. Lime has been
selected as the sulfur-getter for this program.
"The program reported here was divided into two phases. In Phase I,
the problem was directly attacked on a pilot-unit scale. The results of this
work indicated that the program should be redirected (Phase n) to smaller-
scale test apparatus so that more basic data could be obtained for eventual
scale-up to pilot scale.
-------
"In the initial project phase, a coal-lime mixture was experimentally
treated at atmospheric pressure with a reducing .gas in a heated, fluidized-
bed reactor. This reactor could treat up to 200 Ib/hr of mixture to
temperatures of 1200°F. The coal used in the initial tests was from the
Illinois No. 6 seam and contained about 3% sulfur.
"Work in the initial program phase resulted in the discovery that less
sulfur was removed than expected at these conditions. Two factors were
believed responsible:
1. The coal heat-up rate in the fluid!zed bed was nearly instantaneous,
which appears to cause organic sulfur fixation.
2. The coal showed signs of weathering; therefore, the total sulfur
content was not readily available for hydrogen treatment.
"At this point, the program was redirected (Phase n) to the operation
of smaller-scale test units that featured controlled heat-up rates. The
smaller-scale units also permitted an increased number .of tests over a
broader range of conditions, with savings in time and manpower. Coal
samples from several mines throughout the country were obtained for tests
in this equipment.
"A coal-lime mixture was treated with hydrogen, in batch-type
reactors, to temperatures of 1500°F. Heat-up rates, terminal temperature,
residence time, and particle size were the variables tested.
"Preliminary tests eliminated the Western coals (i.e., subbituminous
and lignite) because the sulfur content of the raw coal was low and readily
amenable to treatment. Also, the preliminary tests indicated that the coals
from the Midwestern and Eastern United States required pr.etreatment to
prevent caking during hydrotreating. This is accomplished by heating the
fluidized coal at atmospheric pressure to 750°F in the presence of oxygen.
"On the basis of the preliminary tests with several coals and the
relative abundance of the types of coal, a coal from the Western Kentucky
No. 9 seam was chosen for complete characterization. This coal is from the
Illinois basin and contains over 3% sulfur. Tests were run covering a wide
range of the parameters listed. These tests prove that acceptable sulfur
levels were attained at treatment temperatures of 1500°F. The higher tem-
peratures result in significant tar.removal and some gasification of the coal.
These effects necessitate further research into quantity, chemical makeup,
and handling of gas and liquid streams.
"The testing resulted in the discovery that treatment with lime does
not capture all the sulfur that is released from the coal. A more thorough
examination of the effectiveness and benefits.of lime is required in future
work.
"A conceptual process design, based on laboratory- and bench-scale
data, is presented. That process will produce a solid fuel that can be burned
directly in conformance with Federal EPA New Source Performance
Standard (NSPS)."
-------
At the end of the previous contract, therefore, a conceptual process had been
identified but could not be defined because of an insufficient data base. The section
entitled "Future Work" included:
"Necessity for Lime
"One of the primary objectives to consider is the necessity of using
lime. Some data indicate that the use of lime is not imperative; the process
could be simplified if the lime were eliminated. Problems have been
experienced with coal-lime separations, loss of carbon values to the lime,
and capture of lime by the coal. These problems were not unexpected in the
original plan for the process, but the effect is more pronounced than
desirable.
"Elimination of the lime would reduce the complexity of the process.
The reactors could be made smaller, and gas usage would decrease because
less material would be handled. Larger off-gas treatment facilities would be
necessary to handle the increased sulfur in the off-gas. Studies must be
made to determine which operating approach is economically and
operationally superior.
"Other Coals
"Tests using other, typical sulfur-bearing coals should be made in the
thermobalance and batch reactors. The results will be compared with results
already obtained. The relative value of heating rates and holding times will
be evaluated.
"Pilot Unit
"Tests should be made on the 10-inch unit used previously. The
larger-scale operation and increased material generated are necessary for
determining details to complete the process flow sheet. In particular, the
determination and distribution of sulfur types in the off-gas during
continuous operation are needed, so that treatment facilities can be
designed.
"If a heating rate must be imposed on the particle (other than the
rapid heat-up in the fluidized-bed arrangement), the 10-inch unit will require
modification. Further work is needed in the thermobalance and batch
reactors to determine the optimum heat-up rate.
Concept Design
"When test work is completed, data would be used to generate an
overall conceptual design for the process. This would include energy and
material balances, economic studies, and all of the treatment steps to
produce a low-sulfur fuel from coal."
The present work has been directed at proving these points.
-------
The organization of this report is as follows: Detailed discussion of materials,
equipment, and operating procedures are omitted; these subjects are fully described in
the above-mentioned report on the earlier program phases. Where new coals, equipment,
or techniques were employed, these are described in the section of the report pertaining
to their use.
The first section of the report, Coal Preparation, discusses experimental efforts in
the plant.section upstream of the hydrodesulfurization reactor. Work was done on coal
crushing and coal pretreatment.
Discussions of the hydrodesulfurization reaction are presented in the order of
increasing equipment size -r laboratory, bench-scale, and 10-inch continuous feeding
systems. A short discussion is presented on coal nitrogen reduction during hydrode-
sulfurization, and combustion methods for utilization of the treated coal are identified.
The economic studies include the development of a conceptual process. Also, the
equipment requirements are described for a continuous Process Development Unit (PDU)
for proof of the overall process concept on an integrated basis.
Finally, the next steps in the development of the system are outlined.
-------
COAL PREPARATION
CRUSHING
A quantity of Illinois No. 6 coal was obtained. Analyses for the run-pf-mine coal
are given in Table 1. It is much higher in ash and sulfur content and lower in fixed
carbon than earlier samples of washed coal.
This coal was used in crushing tests by the T. J. Gundlach Machine Co. The
purpose of the tests was to determine conditions to minimize fines in crushing and
preparation. These data will be used for design work. Gundlach's crusher has the
advantage of reduced fines production over other types of crushers.
Three tests were used with one pass of coal through the crusher. Table 2 lists the
screen analysis for feed and the material produced from each test; the feed material was
initially screened at 10 mesh to remove the fines material from the feed. The three
tests were made at crusher speeds of ZOO, 300, and 400 rpm. The merits of each can be
seen in the screen analysis. Lower speeds produced fewer fines, but increased the
amount of oversize material to be recycled for recrushing. Increasing the, speed reduces
the amount recycled, but increases the fines. Some of the material was crushed to 100%
-8 mesh for use in pretreatment and desulfurization tests.
Other work at the contractor's site indicated that the top size required for
satisfactory operation of an 8-foot-diameter pretreater was about 14 mesh. Screening of
mid-continent coals at 12 mesh resulted in a sufficiently low quantity of +14 mesh coal
that pretreatment was acceptable in that pilot plant unit.
Analysis of the crushing tests, assuming a closed-loop crushing around a 12 mesh
screen, indicates that the crushed and screened product should contain less than 12%
100 mesh material. This feed should be satisfactory for the operation of the pretreater
and hydrodesulfurization reactor with minimum elutriation of fines.
PRETREATMENT
Many U.S. coals require a step called pretreatment before they can be satisfac-
torily processed in fhiidized-bed reactors at elevated temperatures. Tests with the
reaction system proposed for this program indicated that pretreatment will also be
required in the coal desulfurization process.
Laboratory- and bench-scale hydrodesulfurization tests prove that pretreatment
not only prevents caking within the reactor, but it also increases the sulfur removal in
the subsequent hydrotreating step. Figure 1 represents two series of thermobalance tests
made with Western Kentucky No. 9 coal. One test series was made with crushed and
screened coal; the other test used crushed, screened, andpretreated coal as feed for
hydrodesulfurization. The results show that the 70% sulfur removal (based on the initial
feed), as achieved with untreated coal feed, was increased to 95% by using a pretreated
-------
TABLE 1. ILLINOIS NO. 6 COAL ANALYSIS
(HILLSBORO MINE)
Proximate Analysis, wt %
Moisture 12.02
Ash 22.83
Volatile Matter 30.18
Fixed Carbon 34. 97
Ultimate Analysis, wt % (dry)
Ash 25. 95
Carbon 57.07
Hydrogen 4. 01
Sulfur 5.06
Nitrogen 0. 98
Oxygen 6. 82
Heating Value, Btu/lb 10,198
-------
oo
TABLE 2. SCREEN ANALYSIS FOR CRUSHING TESTS
% Retained in
Indicated Sieve Feed 200 rpm 300 rpm 400 rpm
2 in.
1 in.
3/4 in.
1/2 in.
1 /4 in.
6 mesh
8 mesh
1 2 mesh
20 mesh
50 mesh
70 mesh
100 mesh
Pan
0
8.6
10.1
15. 9
29. 8
13.7
7. 7
7. 0
3. 9
1.0
0.4
0. 3
1.6
0
0
2.9
13.2
23.7
13. 8
13.0
16.9
9.1
2.1
1.4
3.9
0
0
0.6
5.1
14.1
10.6
12.8
24.4
19.6
4.0
2.6
6.2
0
0
0
2.6
7.2
6.7
9.3
22.9
28.1
6.9
4.8
11.5
-------
1
UJ
o:
a:
0
10
20
30
40
50
60
TO
80
90
100
_\
\
- \
REMOVAL DURING PRETREATMENT
V
-TESTS USING RAW WESTERN KENTUCKY NO. 9
/TESTS USING PRETREATED
WESTERN KENTUCKY NO. 9
I I
I
I
I
I
I
750 800 900
1000 1100 1200 1300
TEMPERATURE, °F
1400 1500
A77030623
Figure 1. Sulfur removal indicating effect of coal pretreatment.
-------
feed. Note that this increased removal was not due to sulfur removed in pretreatment:
Sulfur removed initially during pretreatment, primarily pyritic sulfur, is also readily
attacked in low-temperature (800° to 1000°F) hydrotreatment; the improved sulfur
removal after pretreatment is obtained by more complete removal of organic-type
sulfur. The more complete removal may be caused by the increase in coal pore size
during pretreatment, resulting in better contact of the hydrogen with the coal sulfur and
larger passages for removal of the resultant hydrogen sulfide. Also, oxidative treatment
of sulfur compounds is expected to activate the sulfur for further reactions.
Pretreatment is required in many coal conversion processes and has been the
subject of investigation at several laboratories. Even so, the mechanism of pretreatment
is little understood and is the subject of disagreement among coal investigators. The
discussion here is based upon a) specific tests conducted for this program, b) tests
conducted for a parallel program utilizing the same coal, and c) previous data obtained at
IGT and other laboratories on this phenomenon. The data from the parallel program
provide a substantial input to this understanding, and the sponsors of that program have
consented to release the results of that study into this project.
Many coals from the Eastern United States are considered to be "agglomerating."
Historically, this agglomerating tendency was described as a "softening" of the coal
particle as it was heated through its "plastic range" - about 600° to 900°F. The softened
coal particles would adhere to each, other, causing an increase in the average particle
size, characterized as agglomerating or caking. These coals, when examined by time-
lapse or slow-motion microphotography of heated particles, would actually turn fluid in
the plastic range and resolidify at higher temperatures. The explanation presented for
this effect was a softening of the coal, actually dissolving into its low-melting constit-
uents, followed by polymerization of the melt to a different form of,.coal, characterized
as coke or char. These studies, at other laboratories, have provided a graphic illustration
of the phenomenon that must be overcome.
The historic approach to pretreatment is light oxidation of the coal particles with
air at temperatures in the range of 700° to 800°F. Other approaches have also been
considered, but the air-pretreatment appears well suited for incorporation into the
proposed flowsheet. The purpose of the pretreatment study here was to better define the
conditions necessary for this operation.
The only real measure of satisfactory pretreatment is non-agglomeration of the
coal in the downstream processing equipment. This effect is not readily measured in the
analytical laboratory, so other tests have been devised for laboratory evaluation of the
caking characteristics of the coal.
* Free-swelling index; This laboratory test measures the swelling of coal mass
while being heated. The test was developed primarily to indicate effects that
might occur with different coals in a coke oven. In general, a coal with a high
free-swelling index will be caking, and some investigators claim that reduction of
the free-swelling index to the range of 1.0 to 2.0 is an indication of satisfactory
pretreatment.
* Reflectant borders; When air-pretreated coal is examined microscopically, the
edges of the particles show a greater light-reflectance than the interior of the
coal. It has been hypothesized that the edges of the particles either may have a
10
-------
^high ash content or may be .coked by the action of the air, forming a skin. This
skin is assumed to retain .the1 fluids generated as the coal is heated, arid to keep
the surface of the particle from becoming adherent. .
,.» Boat test; The coal is heated under inert atinosphere with a programmed
. time/temperature profile.while contained in a boat made of stainless steel screen.
The resultant material may a)"fuse,into a single cake for severely agglomerating
coals, b). sinter into a porous block for mildly caking coals, or c) be free flowing
after the test. Intermediate degrees of caking can be noted, but the test is
subjective for all degrees of caking worse than a free-flowing material.
Based upon the results of this recent work, the boat test is considered to be the
best measure of satisfactory pretreatment. Work in other studies has succeeded in
reducing the free-swelling index to low values, but the material still agglomerates in the
boat test. Also, in this work it has been found that some coals may be satisfactorily
pretreated, even if no reflectant borders are generated. Although the boat test is
subjective, yielding results that cannot be quantified numerically, and only indicates a
"go or no-go" situation, it has been found to give results that are safest in assuring satis-
factory operation in downstream equipment.
In addition to the laboratory tests, a visual examination of a pretreater effluent
provides a qualitative estimate of satisfactory operation of the unit. The raw coal is
angular, but, during pretreatment, the coal swells into rounded particles. The occurrence
of this effect is not sufficient evidence of pretreatment, but provides the operator with a
quick, qualitative estimate of successful operation.
An extensive series of tests in both the modified batch reactor and the
KHnch-diameter pilot unit has been conducted on the Western Kentucky No. 9 coal to
evaluate pretreatment conditions. The operation of these experimental units and the
techniques of analysis of the feed and product streams have been detailed in the Final
Report under EPA Contract No. 68-02-1366 (the previous contract on this coal
desulfurization project). At the conclusion of the program under Contract No. 68-02-
1366, a series of batch reactor tests had been run under a wide variety of temperatures,
oxygen feed rates, and residence times without achieving satisfactory pretreatment. The
results that follow are based upon the output of a parallel program that continued during
the interim between Contracts No. 68-02-1366 and 68-02-2126. The specific details of
the tests are not presented because they are proprietary to that program's sponsor;
however, the sponsor has consented to release the results of those tests to this program.
Photomicrographic examination of the residues from the initial, unsatisfactory
pretreatment tests indicated that some particlesNwere excessively oxidized while others
were essentially untreated, resulting in a mixture that would still sinter in the boat test.
Consequently, mixing in the fluidized-bed reactor was found to be an important para-
meter. The initial tests had been run at linear gas velocities well above the minimum
fluidization velocity, but the velocity was not sufficient to ensure full mixing within the
bed. Subsequent tests indicated that a velocity of at least 0.75 ft/s, measured at the bed
conditions, was required to achieve satisfactory mixing and pretreatment of the 20+80
mesh coal feed. This minimum velocity was probably a function of the mechanical
characteristics of the pretreatment vessel, and experience has shown that the mixing
velocity might be reduced in larger equipment. However, this velocity is one of the
parameters that control the size of the full-scale equipment; higher velocities are
desirable to minimize equipment size (but increase fines elutriation). The primary
difficulty encountered with the specified mixing velocity is the requirement of additional
fluidizing gas, in addition to the reaction air required, in some smaller-scale tests.
11
-------
A series of tests was next made in the batch reactor with adequate mixing and
different quantities of reactant air at a temperature of 750°F. In all cases, boat tests
proved that the pretreatment was adequate. Photomicrographic examination showed the
thickness of the reflectant coal border varied directly with the quantity of air used.
Satisfactory pretreatment was even accomplished with this coal in a nitrogen
atmosphere, indicating that the formation of a protective skin on the coal particles is not
a neccesary condition for satisfactory pretreatment of this particular coali 'In general, it
was found that satisfactory pretreatment resulted if the volatile matter content of the
coal was reduced below a specific level by any combination of time, temperature, or
oxygen consumption that would achieve this devolatilization.
Although the volatile matter content of the pretreated coal appeared to be the
controlling parameter for this coal, the mechanism for achieving this devolatilization
must be considered. After examination of energy balances, material consumption, and
energy requirements of the overall desulfurization system, the specifications for the
pretreatment system were written. These specifications included the following:
o Operating temperature 750°F
o Minimum residence time 30 min
o Oxygen feed - 1 SCF O2/lb dry coal
o Fluidization velocity 1 ft/s measured at operating conditions.
Analyses for raw coal and coal pretreated at these conditions are given in Table 3.
A flow sheet based upon the results of operation of the 10-inch unit for the Western
Kentucky No. 9 coal is shown in Figure 2.
With the operating conditions described, the pretreater off-gas contains
significant heating value in the form of reducing gases, tars, and coal fines. The fines
would largely be returned to the bed by internal cyclones in a full-scale unit. Cooling of
the off-gas for desulfurization and separate recovery of tars and fines should not be
done, because of the significant sensible heat that would be lost. The gas should be
burned directly (as in a CO-boiler) for recovery of energy for input elsewhere in the
process, followed by desulfurization of the stack gas.
The pretreatment reaction results in the partial removal of sulfur from the coal.
For the Western Kentucky No. 9 coal, approximately 28% of the sulfur is removed. The
sulfur appears primarily as sulfur dioxide with smaller quantities of carbonyl sulfide and
traces of other organic compounds. Hydrogen sulfide does not appear to be a significant
product of this pretreatment reaction.
The operating conditions for the above work were used in several runs in the
10-inch-diameter continuous units. A confirmation of the batch reactor tests and pro-
duction of a quantity of pretreated char for subsequent hydrodesulfurization tests
resulted.
A similar study was done with Illinois No. 6 coal. The batch reactor was used with
various amounts of oxygen usage and treatment times. On the basis of the tests, an air
consumption of 1 SCF O2/lb of coal with a 30-minute residence at 750°F was found to be
sufficient for adequate pretreatment.
12
-------
SCF
CO 20.18
02 2.46 \ ,
CO2 28. 77
H2 2. 77
CH« 10.29
C2H6 3. 96
C3Hg 1.98
C4H10 1.98
>C5 6. 77
(4. 68 Ibs H2O From
Re ax)
<~rva1 |k.
100 Ibs Coal (Dry)
Ash 11.40
Residence
1 Hour
A
7
Fines
ts
4.63 Ibs (Dry)
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
(0. 22 Ibs H
Carbon 69.48
Hydrogen 4. 66
fir A f\ » TVl- 1^-
Nitrogen 1. 51 As needed
Oxygen 8. 92 for fluidization
(6. 04 Ibs H2O)
1. 28
2. 01
0. 14
0. 22
0. 04
0. 94
,rn 7
't> Tars and Oils 2. 96 Ibs (Dry)
Ash 0.70
Carbon 1. 62
Hydrogen 0. 08
fulfill- n in
OU1-I.U1 U. 1 I/
Nitrogen 0. 04
^r Oxygen 0.42
Water (0. 06 Ibs H2O)
V
Treated Coal
N2 376 SCFH 86. 31
O2 100 SCFH Agh
Ibs (Dry)
9. 42
Carbon 61. 97
Hydrogen 3.42
Sulfur
2. 78
Nitrogen 1. 39
Oxygen 7. 23
(0.87
Ibs H2O)
Figure 2. Pretreater flowsheet (basis: 100 lb dry Western Kentucky No. 9 coal).
-------
TABLE 3. TYPICAL ANALYSIS OF RAW AND PRETREATED COAL
Coal Pretreated Coal
wt %
Proximate Analysis
Moisture
Volatile Matter
Ash
Fixed Carbon
Total
Ultimate Analysis
Ash 11.24 11.25
Carbon 70.00 71.40
Hydrogen 4.54 4.06
Sulfur 3.74 3.16
Nitrogen 1.53 1.64
Oxygen 8.95 8.49
Total 100.00 100.00
The 10-inch unit was operated to pretreat the Illinois No. 6 coal. The conditions
determined from the batch reactor runs were used as operating guidelines. In this test,
the feedstock was Illinois No. 6 coal that had been crushed to a size consist of 14 mesh
by 0. The feed rate was approximately 50 Ib/hr, yielding a residence time in this unit of
40 minutes. The air flow rate was adjusted to provide an oxygen addition of 1 SCF O^/lb
of coal fed. Additional nitrogen was added to the gas flow to ensure sufficient fluidi-
zation. The operating temperature during the steady-state portion of the run was 750°F.
These operating conditions represent approximately the minimum severity for effective
pretreatment, as determined from the batch reactor runs reported above. The
pretreatment of the coal was satisfactory during this run, as evidenced by the free-
flowing characteristics of the product in the empirical boat test for agglomeration.
The proximate analysis for the feed and the pretreated coal product of this test is
presented in Table 4.
TABLE 4. PRETREATMENT OF ILLINOIS NO. 6 COAL
Feedstock Pretreated
Proximate Analysis Coal, wt % Coal, wt %
Moisture 2.3 0.8
Volatile Matter 34.0 24.6
Ash 8.1 8.2
Fixed Carbon 55.6 66.4
14
-------
In examining this proximate analysis, the data for this test appear suspect
although the volatile matter content of the pretreated coal has been reduced to the
range normally associated with satisfactory pretreatment, the ash content of the
pretreated coal is nearly identical to the feedstock. This similarity in ash content would
indicate minimum reaction of the oxygen with the coal. Examination of the ultimate
analyses of all streams around the pretreater, as presented in Figure 3, indicates other
inconsistencies with prior pretreatment tests. For example, the total mass of pretreated
coal, fines, and scrubber material is 97.7% of the feedstock, indicating that only 2.3% of
the coal is consumed into off-gases and water. Further, the hydrocarbon content of
these off-gases is low - only 10 Btu/SCF.
Although the raw data appear suspect, the material balances (both overall and
component) presented in Table 5 are excellent. These good material balances add
credibility to the data. Therefore, results are presented here with the caveat that,
although the data appear good, they do not agree with earlier results, arid further
pretreatment testing is required.
The development of the material balances requires further explanation. First,
because of the equipment configuration, the cyclone underflow (fines) and scrubber dis-
charge cannot be quantitatively separated for the steady-state portion of the run. For
these tests, therefore, the total material collected in the cyclone underflow and the
scrubber was allocated to the steady-state portion of the run according to the time of
operation. The excellent ash balance for the run verifies this calculational technique.
The equipment, also, does not permit direct determination of the quantity of water
manufactured in the pretreater. Two approaches are possible for estimating this water
production: forcing the hydrogen balance or forcing the oxygen balance. Neither of
these approaches is entirely satisfactory. The oxygen contents of the solid materials are
determined by difference, and errors in any of the analyses will be reflected in the
oxygen content reported. However, forcing the hydrogen balance requires the
differencing of similar numbers and the high leverage of change in hydrogen weight
against amount of water produced. For this material balance, the decision was to force
the oxygen balance, primarily because of the leverage factor in forcing the hydrogen
balance. One other calculational point in the material balance is that the air addition
was calculated without the addition of the excess fluidizing nitrogen as would be
experienced in a larger unit and the off-gas compositions were back-calculated to
account for this effect. In general, however, the total and component material balances
for the test are excellent.
The heat balance for the pretreatment test is presented in Table 6. The balance
as presented agrees within 0.1%, with slightly greater heat output than input. This
balance is calculated on the basis of a. larger unit, without the use of the excess
fluidizing nitrogen and electric heaters that are employed on the test run with the
10-inch-diameter reactor. These data indicate that no excess heat would be available for
steam generation under these conditions in contrast to earlier small-scale tests, but
tend to support the operation of larger scale units as extrapolated to these operating
conditions.
An overall evaluation of these data indicate that, on the commercial scale, the
recovery of heat content in the coal across the pretreatment section would be excellent.
The test apparatus has no system for recovery of fines, but, in a larger unit, the fines
would report to the product because of internal cyclones. Therefore, referring to
Figure 3, over 90% of the dry coal input would be expected in the pretreated product.
15
-------
I
T
FINES
1 7fi7 Ih (DRY)
COAL B*=-
100 Ib (DRY)
PRETREATER
wt »'
ASH 10.30
CARBON 71. 57
HYDROGEN 4. 17
SULFUR 2.74
NITROGEN 1.43
OXYGEN 9.79
-^ r^nrmw- A-₯-I
82.39 Ib
wt % A
ASH 8. 31 T ASH
CARBON 73.90 |AIR CARBON
T"^ f^lV/F
HYDROGEN 4.81 I CrF X / h PHA! HYDROGEN
SULFUR 2.43 ' SCF °2/lb COAL SULFUR
NITROGEN 1.60 NITROGEN
OXYGEN 8. 95 OXYGEN
SCRUBBER MATERIAL
7.65 Ib (DRY)
wt %
ASH 8.89
CARBON 74. 50
HYDROGEN 4.84
SULFUR 1.96
NITROGEN 1. 31
OXYGEN 8. 50
ED COAL
(DRY)
wt %
8. 34
75. 57
4. 08
2. 29
1.61
8. 14
GASES
(N2- AND AIR-FREE)
vol %
CO 19.0
COj 61.2
H, 3. 3
CH4 9. 9
ETHANE 3. 3
OTHERS 3.3
SULFUR GASES
ppra
SOj 3300
H S 50
COS 415
OTHER 290
A76122744R
Figure 3. Pretreater material balance, Illinois No. 6 coal.
-------
TABLE 5. PRETREATER MATERIAL, BALANCE
ILLINOIS NO. 6 COAL
Material In
Coal (Dry)
Weight, Ib 100
Ash 8. 31
Carbon 73. 90
Hydrogen 4. 81
Sulfur 2. 43
Nitrogen 1.60
Oxygen 8. 95
Material Out
Pretreated Coal Fines
Weight, Ib 82. 39 7.67
Ash 6.84 0.79
Carbon 62.26 5.49
Hydrogen 3. 36 0. 32
Sulfur 1.89 0.21
Nitrogen 1.33 0.11
Oxygen 6. 71 0. 75
Air
38. 25
29.34
8.91
Scrubber
Tars
Solids & Oils
6.41 1.24
0.68 0.00
4.63 1.07
0.26 0.11
0.13 0.02
0.10 0.00
0.61 0.04
Total
138.25
8.31
73.90
4.81
2.43
30.94
17.86
Off-
Gases Total
40.76 138.
0.00 8.
0.45 73.
0. 98 5.
0.18 2.
29.40 30.
9.75 17.
47
31
90
03
43
94
86
17
-------
oo
TABLE 6. PRETREATER HEAT BALANCE
(BASIS: 77°F, 100 Ib DRY COAL)
HEAT IN
Coal. Dry
Water in Coal
Air. 476 SCF
Total In
Pretreated Coal
Fines
Scrubber Material
Tars
Solids
Gases
N2
02
CO
CO2
Hz
CH4
C2Ht
Others
H2O (from reax)
H2O (in coal feed)
Total Out
Ib CTO Btu/lb -°F
100.0 0. Z54
2.3 1.00
0. 24
Ib Cp,Btu/lb-°F
8Z. 39 0. 254
7.67 0.254
1.24 0.446
6.41 0.254
SCF
29.40 377.0
0.83 9.3
0. 18 2. 3
0.91 7.4
0.002 0.4
0.05 1.2
0.03 0.4
0.4
9. 18
2.31
Enthalpy ,Btu
0
0
0
0
HEAT
Enthalpy ,Btu
14,084
1,311
372
1,096
8.918
2 26
55
228
9
42
23
30
12, 925
3.252
42, 571
Heating Value. Btu/lb
13,169
0
0
OUT
Heating Value, Btu/lb
13,022
12,449
17,188
12,698
Heating Value, Btu/lb-mol
--
--
121,718 '
--
123,090
383, 395
671,634
--
--
..
Total Heating Value, Btu
1,316,900
0
0
1,316,900
Total Heating Value, Btu
1,072,882
95,484
21,313
81,394
--
--
782
--
137
1,281
748
1,600
--
..
1,275,621
Total, Btu
1,316,900
0
0
1,316,900
Total, Btu
1,086,966
96,795
21,685
82,490
8.918
226
837
228
146
1.323
771
1.630
12,925
3,252
1,318,192
B761 22815
-------
In the test unit, the scrubber material contains both extreme fines which escape
the external cyclone and tars. In the analysis of Table 5, these components were
separated and,show a relatively high quantity of solids. This high quantity of solids is
present because the feedstock was not screened for bottom size, m a commercial unit,
the heating value of these solids, in addition to the tars and off-gases, would be
recovered in a separate boiler.
:. f
In summary of this pretreatment test, the data appear excellent because of the
good closure of material and energy balances. However, the low quantities of light
hydrocarbons in the off-gases and the high solids recovery around the unit compared
with earlier tests - add an element of doubt to the data. A possible explanation of the
difference in these test results from the body of data collected in other programs at the
contractor's pilot plant lies in the feed size consist of the feedstock and the method of
feeding the 10-inch-diameter PDU reactor. This feed had not been double-screened for
removal of .fines and the feed was introduced at the bottom of the bed,;at the point of air
injection. It appears that the air preferentially reacted with the coal fines, because of
the high surface area of this size fraction, rather than with the bulk of the coal. In this
case, the necessary heat release was available to pre treat the mid-continent coal, but
other data, more representative of a commerical reactor configuration, should be used
for a design basis.
Batch reactor tests were also made with the two Pittsburgh-seam coals to
determine pretreatment conditions. Continuous unit runs were not made with these coals
because of supply and success with predicting pretreatment conditions with the small
reactor.
Results for the West Virginia-mine coal are presented in Table 7. In each test, the
coal was fhiidized with nitrogen while being heated to 750°F. Air was then added for the
time given at a rate to yield 1 or 2 SCF C^/lb of coal. As expected, this coal needs a
more severe pretreatment than the Western Kentucky No. 9. Conditions of 30 minutes
pretreatment and an air consumption of 2 SCF O^/lb of coal for Run BR-P75-1 were not
sufficient to prevent agglomeration in the boat test. Run BR-P75-2, made at the same
amount of OT consumption, but over a 60-minute period, was free flowing when a sample
was subjected to the boat test. The volatile matter and sample weight loss were greater
in this test than in the first. In the third test, BR-P75-3, the residence time was
maintained at 60 minutes, but the O? consumption reduced to I SCF/lb of coal. Although
the volatile matter and weight loss were similar to that of BR-P75-2, the treatment was
not sufficient, as there was some agglomeration when a sample was boat tested. Based
on these data, the necessary pretreatment conditions for this coal are 1 hour residence at
750°F with 2 SCF C^ consumed per pound of coal.
The results for the Pennsylvania-mine, Pittsburgh-seam coal pretreatment are
presented in Table 8. Procedures for heating and air introduction were the same as with
the other coal. Run BR-P75-4 was made with 1 SCF C^ over a 30-minute period. Runs
BR-P75-5 and BR-P75-6 were made with 2 SCF O2/lb of coal with residence times of
30 minutes and 60 minutes, respectively. All of these samples were non-agglomerating in
the boat test. This coal has a very high ash and a lower volatile content than the West
Virginia coal from the same nominal seam. It is, therefore, easier to pre treat, and
conditions of 1 SCF C^/lb of coal over 30 minutes residence time should be sufficient to
render it noneaking.
19
-------
TABLE 7. ANALYSIS FOR PRETREATMENT OF PITTSBURGH SEAM (W. VA. ) COAL
Coal
BR-P75-1
Proximate Analysis wt%
Moisture
Volatile Matter
Ash
Fixed Carbon
Total
2. 2
35. 9
10.6
51. 3
100. 0
0. 5
27. 7
11.4
60.4
100.0
BR-P75-2
0. 3
25. 5
13.0
61.2
100.0
BR-P75-3
0. 5
25. 7
12.6
61. 2
100. 0
to
O
Ultimate Analysis wt% (Dry)
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
Weight Loss % (Dry Basis)
Gross Heating Value Btu/lb
Boat Agglomeration Test
O2/lb Coal, SCF
Time at 750°F Min
10. 87
73.40
4. 87
2. 77
1. 37
6. 72
11.43
72. 70
4. 14
2. 26
1.46
8. 01
13.07
71 . 50
3. 93
2. 36
1.42
7.72
12.62
72. 30
4.08
2.44
1.42
7.14
100. 00
13,185
100.00
12.9
12,589
Agglomerated
2
30
100.00
16.5
12,294
Free Flowing
2
60
100.00
16.2
12,491
Slight Agglomeration
1
60
-------
TABLE 8. ANALYSIS FOR PRETREATMENT OF PITTSBURGH SEAM (PENN. ) COAL
Proximate Analysis wt%
Moisture
Volatile Matter
Ash
Fixed Carbon
Total
Coal
3.0
26. 0
33. 3
37.7
100.0
BR-P75-4
0.3
19.7
35. 3
44. 7
100.0
BR-P75-5
0.6
18.3
36. 2
44.9
100.0
BR-P75-6
0.5
18.8
37.7
43.0
100.0
Ultimate Analysis wt% (Dry)
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
34. 34
52. 50
3. 54
1.35
1. 08
7.19
100. 00
35.41
52. 10
2. 94
1. 23
1. 13
7. 10
100. 00
36.44
50. 90
2.69
1.11
1. 14
7.72
100.00
37. 94
49.20
2.78
1.13
1.08
7.87
100.00
Weight Loss % (Dry Basis)
Gross Heating Value Btu/lb
Boat Agglomeration Test
O2/lb Coal SCF
Time at 750°F, Min
9,208
13.7
8,830
Free Flowing
1
30
16.5
8, 506
Free Flowing
2
30
16.7
8,262
Free Flowing
2
60
-------
COAL PREPARATION - CONCLUSIONS
Coal-crush ing and pretreatment testing ha ve pro ved:
© A coal-crushing circuit can be designed to minimize fines production and hence elutriation losses.
© Eastern coals can be satisfactorily pretreated so that they are non-agglomerating in thefiuidized-bed
hydrotreatmentprocess unit.
22
-------
LABORATORY-SCALE TEST WORK - HYDRODESULFUREZATION
WESTERN KENTUCKY NO. 9 COAL
A series of thermobalance tests was made with the pretreated Western Kentucky
No. 9 coal. The thermobalance feed material was screened at 40 mesh so material would
not be lost through the stainless mesh basket. Analyses for the coal, pretreated coal, and
+40 mesh pretreated coal are listed in Table 9. Apparently the sulfur is not evenly
distributed in the different size fractions of the coal, and "equivalent" sulfur values in
the raw and pretreated coal were back-calculated for the +40 mesh fraction for data
analysis.
The 10 thermobalance run results are shown in Table 10. Coal and pretreated coal
values have been back-calculated to reflect +40 mesh sulfur contents. Calculations for
the table were based on 100 .lb of coal (dry basis) before pretreatment, yielding 90.84 Ib
after pretreatment. The pretreated coal, when mixed, is blended with lime in a
2:1 lime/coal ratio by weight. Weights after testing are the amounts recoverable from
100 lb of dry coal feedstock. The final sulfur percentages in the reduced data assume
sulfide and sulfate removal by washing or mechanical means.
Tests were run in pairs, with identical conditions imposed: the first with a coal
and lime mix and the second with coal only. The first two tests (TB-76-1 and TB-76-2)
were heated at 5°F/min to 1300°F and held at that temperature for 30 minutes. The
sulfur values in the treated coal are not significantly different at 0.82% and 0.76% or in
sulfur-by-type distribution. Considerably more treated coal is recovered in the no-lime
test (65.40%) than in the lime test (54.92%).
Tests TB-76-3 and TB-76-4 were heated at 5°F/min to 1400°F and were held for
30 minutes. .Total sulfur and by-type distribution are similar in these tests, with the no-
lime test showing slightly better reduction. As in the first pair of tests, treated coal
recovery is more in the no-lime test.
The 5°F/min rate was used in TB-76-5 and TB-73-6, also. Final temperature was
1500°F with no_ holding time. More sulfur was removed in the test without lime, 97.5%,
than in the one with lime, 92.1%. In the lime test, the treated coal recovery is 52.42%,
without lime the recovery was 63.54%.
TB-76-7 and TB-76-8 were heated to 1500°F at 5°F/min and held for 30 minutes.
Total sulfur percentages are essentially the same. Again, the recovery for the no-lime
test is better than the lime test.
A 20°F/min rate to 1500°F was used for TB-76-9 and TB-76-10. These were held
for 240 minutes to make the total run time similar to the times of the slower heat-up
tests. The longer time at the final temperature results in slightly higher weight losses.
Sulfur values are lower in these tests than any of the previous ones, indicating that the
temperature and holding time are effective. Recoveries follow the same trend as
previous tests.
23
-------
TABLE 9. WESTERN KENTUCKY NO. 9 COAL ANALYSIS
Proximate Analysis , wt %
Moisture
Volatile Matter
Ash
Fixed Carbon
Total
Ultimate Analysis, wt %
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
Coal
5.8
36. 3
10.6
47.3
100. 0
11. 24
70. 00
4. 54
3.74
1.53
8. 95
100. 00
Pretreated Coal
0.8
27.7
11.2
60. 3
100.0
11. 25
71.40
4.06
3.16
1.64
8.49
100.00
+40 Mesh
PR-SP-1
1.2
26.6
13.9
58. 3
100. 0
14.03
68. 60
3. 84
2. 87
1.57
9.09
100. 00
24
-------
TABLE 10. THERMOBALANCE TEST RUN DATA,
PRETREATED WESTERN KENTUCKY NO. 9 COAL
Feed Coal
Run No.
Feed Ratio, lime/coal
Coal W. Ky. No.
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide 0. 02
Sulfate 0. 52
Pyritic 0. 92
Organic 1. 57
Total 3. 03
Weight, gms
Initial 100.00
Treated
Weight Loss, %
Total, wt
Coal, wt
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide 0. 02
Sulfate 0. 52
Pyritic 0. 92
Organic 1. 57
Total 3.03
Sulfur Content, %
Sulfide 0.02
Sulfate 0. 52
Pyritic 0. 92
Organic 1. 57
Total 3.03
Sulfur Removal, wt %
From Feed
From Coal
* Calculated for +40 mesh fraction.
Pretreajed
Coal
750
30
0.01
0. 10
1. 25
1.29
2.65
90.84
9.16
9.16
90. 84
0.01
0. 09
1. 13
1. 17
2.40
0.01
0. 10
1. 25
1. 29
2.65
20. 5
TB-76-1
TB-76-2
Pret.
Feed
0.00
0.03
0.42
0.43
0. 88
3.6829
272. 52
0.01
0. 09
1. 13
1. 1.7
2.40
0.00
0. 03
0.42
0.43
0.88
2/1
W. Ky. No. 9
5
1300
30
Float Sink
0. 28 0. 92
0. 04 0. 04
0.03 0.00
0.47 0.06
0.82 1.02
0.7502 2.4528
13. 04
39. 12
54.92 179.56
0.15 1.65
0.02 0.07
0.02 0.00
0.26 0.11
0.45 1.83
0.03
0.47
0. 50
88. 3
90. 7
0/1
Pret. W. Ky. No. <
5
1300
30
Feed Residue
0.01 0.26
0.10 0.04
1.25 0.04
1.29 0.42
2.65 0.76
2. 5291
1. 8209
28. 00
28.00
90.84 65.40
0.01 0. 17
0.09 0.03
1.13 0.03
1.17 0.27
2. 40 0. 50
0.04
0.42
0.46
87. 5
90. 1
A76040826
25
-------
TABLE 10. THERMOBALANCE TEST RUN DATA,
PRETREATED WESTERN KENTUCKY NO. 9 COAL
(Continued)
Feed Coal
Run No.
Feed Ratio, lime/coal
Coal W. Ky. No.
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide 0. 02
Sulfate 0.52
Pyritic 0. 92
Organic 1. 57
Total 3.03
Weight, gms
Initial 100.00
Treated
Weight Loss, %
Total, wt
Coal, wt
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide 0. 02
Sulfate 0. 52
Pyritic 0. 92
Organic 1. 57
Total 3.03
Sulfur Content, "7,
Sulfide 0. 02
Sulfate 0. 52
Pyritic 0. 92
Organic 1. 57
Total 3.03
Sulfur Removal, wt %
From Feed
From Coal
'Calculated for +40 mesh fraction.
Pretreajed
Coal'
TB-76-3
TB-76-4
750
30
0.01
0. 10
1. 25
1. 29
2.65
90.84
9.16
9.16
90. 84
0. 01
0. 09
1. 13
1. 17
2. 40
0. 01
0. 10
1. 25
1. 29
2. 65
20. 5
Pret.
Feed
0.00
0.03
0.42
0.43
0.88
3. 77.00
272. 52
0.01
0. 09
1. 13
1. 17
2.40
0.00
0. 03
0.4-2
0.43
0.88
2/1
W. Ky. No. 9
5
1400
30
Float Sink
0. 29 0. 92
0.00 0.01
0.02 0.00
0.33 0.19
0.64 1.12
0.8550 2.3944
13.81
41.. 43
61.80 173.08
0. 18 1. 59
0.00 0.02
0.01 0.00
0.20 0.33
0.39 1.94
0. 02
0. 33
0. 35
91.2
93.1
0/1
' Pret. W. Ky. No. <
5
1400
30
Feed Residue
0.00 0.23
0.10 0.00
1.25 0.01
1.29 0.33
2.65 0.57
2.4656
1. 7255
30.02
30.02
' 90. 84 63. 57
0.01 0.15
0.09 0.00
1.13 0.01
1.17 0.21
2.40 0.37
0.01
0. 33
0.34
90. 8
92.7
A76040826
26
-------
TABLE 10. THERMOBALANCE TEST RUN DATA,
PRETREATED WESTERN KENTUCKY NO. 9 COAL
(Continued)
' Pretreajed
Feed Coal Coal
Run No.
Feed Ratio, lime/coal
Coal
Heating Rate. °F/min
Terminal Temperature,
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, gms
Initial
Treated
Weight Loss, %
Total, wt
Coal, wt
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
* Calculated for +40 mesh fraction.
TB-76-5
TB-76-6
Z/l
W. Ky. No. 9 W. Ky. No. 9 Pret. W. Ky. No. . 9
5
750 1500
30 0
100.00
0.02
0. 52
0. 92
1. 57
3.03
0.02
0. 52
0.92
1. 57
3.03
Feed Float Sink
90. 84
9.16
9.16
90. 84
0.01
0. 09
1.13
1. 17
2.40
0.01
0. 10
1.25
1.29
2.65
20. 5
3. 5448
0.6819 2.3701
2. 52
0.01
0.09
1.13
1.17
2.40
0.01
0.10
1.25
1.29
2.65
13. 90
41.71
52.42 182.
0.05 1.
0.01 0.
0.01 0.
0.18 0.
0.25 1.
0.02
0.35
0. 37
92.1
93.7
22
73
09
00
15
97
0/1
Pret. W. Ky. No. 9
5
1500
0
Feed Residue
0.02
0. 52
0. 92
1. 57
3.03
0.01
0. 10
1. 25
1.29
2.65
0.00
0.03
0.42
0.43
0.88
0.10
0.01
0.02
0. 35
0.48
0.95
0.05
, 0.00
0.08
1.08
0.01
0. 10
1.25
1.29
2.65
0. 24
0.00
0.04
0.05
0. 33
2. 2834
90.84
0.01
0.09
1.13
1.17
2.40
0.01
0. 10
1.25
1.29
2.65
1. 5972
30.05
30.05
63. 54
0.15
.0.00
0.03
0.03
0.21
0.04
0.05
0.09'
97.5
98.0
A76040826
27
-------
TABLE 10. THERMOBALANCE TEST RUN DATA,
PRETREATED WESTERN KENTUCKY NO. 9 COAL
(Continued)
^ Pretrea^fed
Feed Coal Coal
Run No.
Feed Ratio, lime/coal
Coal
Heating Rate, F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, gms
Initial
Treated
Weight Loss, %
Total, wt
Coal, wt
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
* Calculated for +40 mesh fraction.
TB-76-7
TB-76-8
2/1
W. Ky. No. 9 W. Ky. No. 9 Pret. W. Ky. No. 9
5
750 1500
30 30
Feed Float Sink
100. 00
3.4669
90. 84
9.16
9. 16
90. 84
272. 52
0.6562 2.3007
14.71
44. 13
51.58 180.84
0/1
Pret. W, Ky. No. 9
5
1500
30
Feed
2. 2871
90.84
Residue
0.02
0. 52
0. 92
1. 57
3.03
0. 01
0. 10
1. 25
1.29
2.65
0.00
0.03
0.4Z
0.43
0. 88
0.11
0.00
0.00
0.40
0.51
0.84
0.08
0.00
0.21
1. 13
0.01
0. 10
1. 25
1.29
2.65
0.19
0.00
0.03
0. 28
0. 50
1. 5766
31.07
31.07
62.62
0.
0.
0.
1.
3.
0.
0.
0.
1.
3.
02
52
92
57
03
02
52
92
57
03
0.
0.
1.
1.
2.
0.
0.
1,
1.
2.
20
01
09
13
17
40
01
10
25
29
65
. 5
0.
0.
1.
1.
2.
0.
0.
1.
1.
2.
01
09
13
17
40
01
10
25
29
65
0.
0.
0.
0.
0.
0.
0.
0.
83
86
06 1. 52
00 0.14
00 0.00
21 0. 38
27 2. 04
00
40
40
. 3
.8
0.01 . 0.
0.09 0.
1.13 0.
1.17 0.
2.40 0.
0.
0.
0.
87
89
12
00
02
18
32
03
28
31
. 1
.8
A76040826
28
-------
TABLE 10. THERMOBALANCE TEST RUN DATA,
PRETREATED WESTERN KENTUCKY NO. 9 COAL
(Continued)
0 Pretrea^ed
Feed Coal Coal
Run No.
Feed Ratio, lime/coal
Coal
Heating Rate. °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, gms
Initial
Treated
Weight Loss, %
Total, wt
Coal, wt
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic '
Organic
Total
Sulfur Content, <%
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
^Calculated for +40 mesh fraction.
TB-76-9
TB-76-10
2/1
W. Ky. No. 9 W. Ky. No. 9 Pret. W. Ky. No. 9
20
750 1500
30 240
Feed Float Sink
100.00
0.02
0. 52
0. 92
1. 57
3.03
0.02
0. 52
0. 92
1. 57
3.03
90. 84
9.16
9. 16
90. 84
0.01
0.09
1. 13
1. 17
2.40
0.01
0. 10
1. 25
1.29
2.65
20. 5
3.6562
0.6918 2.3940
'2. 52
0.01
0.09
1.13
1.17
2.40
0.00
0.03
0.42
0.43
0.88
15.60
46. 79
51.57 178.
0.05 2.
0.01 0.
0.01 0.
0.13 0.
0. 20 2.
0.01
0.25
0.26
94.2
95.4
44
27
02
00
11
40
0/1
Pret. W. Ky. No. 9
20
1500
240
Feed Residue
0.02
0. 52
0. 92
1.57
3.03
0.01
0. 10
1. 25
1.29
2.65
0.00
0.03
0.42
0.43
0.88
0.09
0.01
0.01
0.25
0.36
1.27
0.01
0.00
0.06 .
1.34
0.00
0.10
1.25
1.29
2.65
0.16
0.00
0.02
0.15
0.33
2.0635
90.84
0.01
0.09
1.13
1.17
2.40
0.00
0.10
1.25
1.29
2.65
1.3886
32.71
32.71
61.13
0.10
0.00
0.01
0.09
0.20
0.02
0.15
0.17
95.8
96.7
A760408Z6
29
-------
Sulfur values from the treated material reduced data (Runs TB-76-1 through TB-
76-10) are presented graphically in Figure 4. The resultant sulfur contents (pyritic plus
organic) are shown as a function of temperature. Sulfur content decreases as the
temperature increases and the no-lime tests show consistently better removal than the
lime tests.
Figure 5 shows treated coal recovery as a function of the final temperature.
Characteristics of the coal, coal volatiles, lime, or the float-sink technique may have
resulted in the higher recovery at 1400°F for the mix tests. The no-lime tests show
nearly a straight-line decrease in recovery from 1300°F to 1500°F. Recoveries are
significantly greater for the no-lime tests than when lime is used; the improved recovery
is a factor for future decisions. The probable reason for better recovery is that heavier,
higher-ash particles report to the sink (lime fraction of the float-sink separation); also,
the volatiles are absorbed by the lime during the test. The end result is a reduced
quantity of treated product.
Calculations for SO? emissions for each of the 10 tests are shown in Table 11.
From previous batch reactor work, the heating value of the float-sink treated coal has
been in the range of 10,700 to 11,600 Btu/lb . The lower figure was used for
TABLE 11. CALCULATED SO, EMISSIONS FROM COMBUSTION
OF TREATED COAL
Emission, Ib SO^/IO6 Btu
Total Sulfur Pyritic and
in Treated Organic
Test No. Coal Sulfur Only
TB-76-1 1.53 0.94
TB-76-2 1.4Z 0.86
TB-76-3 1.20 0.66
TB-76-4 1.07 0.65
TB-76-5 0.90 0.64
TB-76-6 0.62 0.17
TB-76-7 0.95 0.75
TB-76-8 0.93 0.58
TB-76-9 0.67 0.49
TB-76-10 0.62 0.32
The small samples available from the thermobalance runs preclude the
experimental measurement of heating value in addition to the required
sulfur analyses.
30
-------
u>
O WITH LIME
A WITHOUT LIME
D PRETREATED COAL
750 800
MOO 1200 1300
FINAL TEMPERATURE, °F
Figure 4. Treated material sulfur content, Western Kentucky No. 9 coal.
-------
NJ
0
8
0
*o
55
Or
UJ
S
o
UJ
or
_i
§
0
o
UJ
^
LJ
or
i-
70
68
66
64
62
60
58
56
54
52
Kf\
O WITH LIME
A WITHOUT LIME
^^
""
rf
o
o
'
c
(
1
\
r-
)
)
1200 1300 1400 1500
FINAL TEMPERATURE, °F A76030772
Figure 5. Treated material recovery, Western Kentucky No. 9 coal.
-------
these calculations, resulting in conservatively estimated emissions. All the tests are
below the 1.2 Ib SO^/million Btu if the sulfide and sulfate can be removed as indicated.
Tests at temperatures of 1400°F and above show acceptable SG>2 emissions even without
removal of the sulfide and sulfate. More definitive values will be obtained from the
batch reactor runs as enough sample is available to determine exact heating values and
the SO2 emissions from them.
PITTSBURGH SEAM - WEST VIRGINIA COAL
An identical series of tests was conducted with the Pittsburgh-seam coal from the
West Virginia mine. Table 12 lists the analyses for the original coal, pretreated coal, and
+40 mesh pretreated coal.
Results from the 10 thermobalance tests are listed in Table 13. Sulfur is not
distributed equally in the different size fractions, so equivalent values are calculated for
the original and pretreated coals. Values are based on 100 Ib of dry coal before pretreat-
ment, which yields 83.5 Ib of pretreated material. In tests using lime, the mixture is 2:1
lime/coal by weight. Final sulfur percentages for the reduced data assume sulfide and
sulfate removal by chemical or mechanical means.
' The tests were run in pairs, at identical conditions, one with pretreated coal only
and one with the mixture. In this way, the value of the lime addition can be measured.
Heat-up rates, terminal temperatures, and holding times at the temperatures are shown
in Table 13.
Comparison of the pairs of tests shows slightly better total sulfur removal in the
lime tests than in the no-lime tests. However, in the reduced data, assuming sulfide and
sulfate removal, the sulfur values are nearly the same for the float or residue of each
pair. The sample from TB-76-14 was accidentally lost during the organic sulfur
determination, and the test was not rerun because of the consistency of the other test
results.
The sums of the pyritic and organic sulfur values from the reduced data are shown
in Figure 6. Sulfur content is reduced as the temperature increases or with longer
holding time at the final temperature.
Treated material recovery is shown in Figure 7. The no-lime tests exhibit better
recovery at all temperatures. A higher recovery for the lime test at 1400°F over the
other lime tests is the same as experienced with the pretreated Western Kentucky No. 9
coal. Perhaps this effect is an interaction of coal, lime, and coal volatiles at this
temperature.
Calculations for SO^ emission from the treated coal samples are listed in Table
14. The pretreated coal has a heating of 12,300 Btu/lb, and a similar value for the final
product was assumed. If only the pyritic and organic type sulfurs are considered, all
tests have acceptable values. Considering the total sulfur, only the tests at 1300°F are
too high in SO^ emission; the rest are below the 1.2 Ib/million Btu limit.
33
-------
TABLE 1Z. PITTSBURGH SEAM, WEST VIRGINIA COAL, ANALYSIS
Pretreated
Coal Pretreated Coal +40 Mesh Coal
Proximate Analysis, wt %
Moisture
Volatile Matter
Ash
Fixed Carbon
Total 100.0 100.0 100.0
Ultimate Analysis, wt %
Ash 10.87 13.07 9.83
Carbon 73.40 71.5 74.80
Hydrogen 4. 87 3. 93 4. 20
Sulfur 2.77 2.36 2.16
Nitrogen 1.37 1.42 1.47
Oxygen 6.72 7.72 7. 54
Total 100.00 100.00 100.00
-------
TABLE 13.
THERMOBAJLANCE TEST RUN DATA, PRETREATED PITTSBURGH SEAM,
WEST VIRGINIA COAL,
Coal*
Pretreatment*
Ui
Run No.
Feed Ratio, lime/ coal
Coal
Heating Rate, F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt % as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
. Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-11
750
60
Feed
0.
0.
0,
1.
2.
. 00
. 42
.63
. 36
. 41
0.
0.
0.
1.
2.
00
27
37
47
11
100
0
0
0
0
0
4.
. 00
. 09
. 12
. 49
. 70
3576
83. 5
0.
0.
0.
1.
2.
0.
0.
0.
j
2.
00
42
63
36
41
00
42
63
36
41
16
16
83
0.
0.
0.
1.
1.
0.
0.
0.
1.
2.
. 5
. 5
. 5
00
23
31
23
77
00
27
37
47
11
250
0
0
0
1
1
0
o.
. 50
. 00
. 23
. 31
. 23
. 77
.00
. 09
0. 12
0.
0,
.49
. 70
2:
1
_ Dt.of Pit-f-
-------
TABLE 13.
T HER MOB A LANCE TEST RUN DATA, PRETREATED PITTSBURGH SEAM,
WEST VIRGINIA COAL (Continued)
Coal*
Pretreatment"
Run No.
Feed Ratio, lime/ coal
Coal
Heating Rate, F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt % as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-13
750
60
Feed
0
0
0
1
2
.00
.42
.63
. 36
.41
100
0.
0.
0.
1.
2.
00
27
37
47
11
0
0
0
0
0
4.
. 00
.09
. 12
.49
. 70
4926
83. 5
0
0
0
1
Z
0
0,
0
1
2
.00
.42
.63
. 36
.41
.00
.42
.63
. 36
.41
16
16
83
0.
0.
0.
1.
1.
0.
0.
0.
1_
2.
. 5
. 5
. 5
00
23
31
23
77
00
27
37
47
11
250
0
0
0
1
1
0
0
0
0
0
. 50
. 00
. 23
. 31
. 23
. 77
.00
.09
. 12
.49
. 70
?,.'
TB-76-14
1 0:1
5 5
1400 1400
30 30
Float Sink
0.
0.
0.
0.
0.
12 0.45
02 0.05
00 0.00
41 0.02
55 0. 52
Feed
0
0
0
1
2
2.
.00
. 27
. 37
.47
. 11
3176
1.0527 2.8916
12.
36.
58.
0.
0.
0.
0.
0.
0.
0.
0.
86
90
20
61
70 161.24
07 0.73
01 0.08
00 0. 00
24 0.03
32 0. 84
00
41
41
.4
.0
83
0
0
0
1
1
0
0
0
1
2
. 50
.00
. 23
. 31
. 23
.77
.00
. 27
. 37
. 47
. 11
Residue
0.26
0.01
0.01
1.6680
28.03
28.03
60.09
0.16
0.01
0.01
0.01
--
--
'Calculated for 40 mesh fraction.
D76071623
-------
TABLE 13.
THERMOBALANCE TEST RUN DATA, PRETREATED PITTSBURGH SEAM,
WEST VIRGINIA COAL (Continued)
Coal*
Pretreatment*
Run No.
Feed Ratio, lime/ coal
Coal
Heating Rate, F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt % as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
'Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Pitt
0. 00
0.42
0.63
1. 36
2.41
100
0.00
0. 42
0. 63
1. 36
2. 41
0.00
0.42
0.63
1. 36
2.41
750
60
0. 00
0. 27
0. 37
1.47
2. 11
83. 5
16. 5
16. 5
83. 5
0.00
0. 23
0. 31
1.23
1.77
0.00
0. 27
0. 37
1.47
2. 11
TB-76-15
?.:!
TB-76-16
0:1 '
5 5
Feed
0: 00
0.09
0.12
0.49
0.70
4. 5513
250. 50
0.00
0.23
0.31
1. 23
1.77
0.00
0.42
0.63
1.36
2.41
1500
0
Float
0.13
0.01
0.01
0.45
0.60
1.0451
12.26
36.77
57. 52
0.07
0.01
0.01
0. 26
0. 35
0.01
0.45
0.46
85.3
88.8
" Sink
0. 54
0.02
0.00
0.03
0. 59
2. 9484
162. 27
0.88
0.03
0.00
0.05
0. 96
Feed
0.00
0. 27
0.37
1.47
2.11
2.4397
83. 50
0.00
0.23
0.31
1.23
1.77
0.00
0.27
0.37
1.47
2. 11
1500
0
Residue
0. 18
0.02
0.01
0.45
0.66
1
1.7610
27.82
27.82
60.27
0.11
0.01
0.01
0.27
0.40
0.01
0.45
0.46
84.2
88.4
(Calculated for 40 mesh fraction.
D76071623
-------
TABLE 13.
THERMOBALANCE TEST RUN DATA, PRETREATED PITTSBURGH SEAM
WEST VIRGINIA COAL, (Continued)
. Pretreatment*
Run No.
Feed Ratio, lime/ coal
Heating Rate. F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt % as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, '.',.
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight. Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, "'.,
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt "'.
From Feed
From Coal
TB-76-17
750
60
Feed
0.
0.
0.
1.
2.
00
42
63
36
41
0.
0.
0.
1.
2.
00
27
37
47
11
100
0
0
0
0
0
4.
. 00
.09
. 12
.49
. 70
5277
83. 5
2:
TB-76-18
1 0:1
5
1500
30
Float Sink
0.
0.
0.
0.
0.
13 0.56
02 0.02
02 . 0.00
33 0.04
50 0.62
5
1500
30
Feed
0. 00
0
0
1
2
2.
. 27
. 37
. 47
. 11
4268
1. 0010 2. <)443
16. 5
0.
0.
0.
I.
2.
0.
0.
0.
1.
2.
00
42
63
36
41
00
42
63
36
41
16
83
0.
0.
0.
1.
1.
0.
0.
0.
1.
2.
. 5
.5
00
23
31
23
77
00
27
37
47
11
250
0
0
0
1
1
0
0
0
1
2
.50
. 00
.23
.31
.23
.77
.00
.42
.63
.36
.41
55.
0.
0.
0
0.
0.
.0.
0.
0.
89
1 Z. H6
3H. 59
38 162.91
OH 0.91
01 0.03
01 0.00
1H 0.07
ZK 1.01
02
33
35
.3
83
0
0
0
. 1
1
0
0
0
1
2
.50
. 00
.23
.31
.23
.77
.00
. 27
. 37
.47
. 11
92.1
Residue
0. 29
0.00
0.01
0. 39
0. 69
1. 7168
29. 26
29. 26
59. 10
0. 17
0. 00
0.01
0. 23
0. 41
0.01
0.39
0.40
. 86.4
90.0
Calculated for 40 mi-sh frar-tinn.
D76071623
-------
TABLE 13.
THERMOBALANCE TEST RUN DATA, PRETREATED PITTSBURGH SEAM,
WEST VIRGINIA COAL (Continued)
Coal*
Pretreatment*
Run No.
Feed Ratio, lime/ coal
Coal
.Heating Rate. F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt % as .
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
. initial
Treated
OJ Weight Loss. t. '
VO
Total Weight
: Coal Weight
Reduced Data
Weight! Ib
Sulfur Weight. Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content. "'-.
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt ",'.
From Feed
From Coal
0. 00
0.42
0.63
1. 36
Z. 41
100
0. 00
0. 42
0. 63
1. 36
2.41.
0.00
0.42
0.63
1.36
2.41
750
60
0. 00
0.27
0. 37
1. 47
2.11
83.5
16. 5
16. 5
K3. 5
0.00
0. 23 .'
0. 31 .
1. 23
1. 77
0.00
0. 27
0. 37
1.47 .
2. 11
Feed
0. 00
0.09
0. 12
0. 49
0. 70
4. 5337
250.50
0. 00
0.23 '
0.31
1. 23
1.77
0.00
0.42
0.63
1.36
2.41
TB-76-19
-2:1
20
1500
240
Float . Sink
0.09 0.52
0. 00 0. 03
0.02 0.00
0.30 0.10
0.41 0.65
0. 9449 2. 9796
13.44
40. 31
52.21 164.62
0.05 0.86
0.00 0.05
0.01 0.00
0.16 0.16
0.22 1.07
0.02
0. 30
0. 32
90.4
92.9
TB-76-20
Seam. W.
Feed
0.00
0. 27
0. 37
1.47
2. 11
2.4042
83.50
0.00
0. 23
0.31
1. 23
1.77
0.00
0. 27
0. 37
1.47
2. 11
;0:1
Va
20.
1500
240
Residue
0. 35
0.00
0.02
0. 32
0.69
1.6607
30. 93
30. 93
57.67
0. 20
0.00
0.01
0. 18
0. 39
0.02
0. 32
0. 34
89. 3
92. 1
"Calculated for 40 rrn-sh f>a<-lion.
D76071623
-------
2.5
2.0
1.5
O WITHOUT LIME
A WITH LIME
D PRETREATEO COAL
UJ
OC
CO
1.0
0.5
750 800
900
1000 1100 (200 1900
FINAL TEMPERATURE,°F
1400
1500 1600
A7606I267
Figure 6. Treated material sulfur content, Pittsburgh seam, West Virginia coal.
-------
. 1 C.
original coal
o>
OD
5
S?
>_- 64
a:
UJ
UJ
a:
< 60
8
o
UJ
UJ
P: 56
52
12
c
1
i
k
c
z
2
1
) WITHOUT LIME
i WITH LIME
k
J
i
)
Y
L
*
i
DO 1250 1300 1350 1400 1450 1500 1550 16
FINAL TEMPERATURE, °F
A7606I266
Figure 7. Treated material recovery, Pittsburgh seam, West Virginia coal.
-------
TABLE 14. CALCULATED SULFUR DIOXIDE EMISSIONS FROM
COMBUSTION OF TREATED PITTSBURGH SEAM,
WEST VIRGINIA COAL
Emission
Test No.
TB-76-
TB-76-
TB-76-
TB-76-
TB-76-
TB-76-
TB-76-
TB-76-
TB-76-
TB-76-
11
12
13
14
15
16
17
18
19
20
Total Sulfur
in Treated Coal
1
1
0
0
1
0
1
0
1
-
. 22
.43
.89
. 98
.07
.81
. 12
.67
. 12
Pyritic and Organic
Sulfur Only
) /in6 "Ptii
1
1
0
0
0
0
0
0
0
. 04
. 00
.67
.75
.75
. 57
.65
.52
.55
42
-------
PITTSBURGH SEAM - PENNSYLVANIA COAL
A series of thermobalance tests was made with the pretreated Pittsburgh-seam
coal (Pennsylvania mine). The original coal, pretreated coal, and +40 mesh pretreated
coal analyses are shown in Table 15. The coal was again screened at +40 mesh for these
tests to prevent loss through the thermobalance basket.
Thermobalance run results are listed in Table 16. Unequal sulfur distribution in
the size fractions requires back-calculation of pseudo-sulfur contents for the coal and
pretreated coal. The bases for calculations are 100 Ib of dry coal before pretreatment
and 86.34 Ib after pretreatment. Final sulfur values, in the reduced data, assume sulfide
and sulfate removal'by mechanical or chemical means. The tests were run in pairs: one
test with pretreated coal only and one with a lime-pretreated coal mix to assess the
value of the lime usage. Other test conditions are as listed in Table 16.
Comparisons of the test.pairs for the lime and no-lime operation, Figure 8, show
little or no difference in the total weight of sulfur removed. The Deduced data treated-
material sulfur percentages.are lower for the no-lime tests than for the lime tests.
Material recovery (Figure 9), however, is higher for the no-lime tests. Sulfur reduction,
in general, is greater as the temperature increases. The holding time at 1500°F did not
appreciably reduce sulfur content.
The calculated SO^ emissions from coal that would be treated the same as these
samples are presented in Table 17. The small sample does not permit evaluation of the
heating value for each test. The assumed heating value of 9150 Btu/lb was estimated
from the known values for the coal and pretreated coal. All the treated material
samples are below the Federal EPA limit of 1.2 Ib SO,/million Btu, even when
considering total, sulfur. The original sulfur content of the coal is low and the treatment
requirements, therefore, are not as severe as with the other coals.
ILLINOIS NO. 6 COAL
A similar series of. tests was made with pretreated Illinois No. 6 coal. Table 18
shows the analyses for the original;coal, pretreated coal, and +40 mesh coal.
Results of the 10 tests are listed in Table 19. The quantities are calculated as
described previously. Values are'based on 100 Ib of dry raw coal, before pretreatment,
and 90.4 Ib after pretreatment.
Analysis of the data shows the lime tests, Figure 10, have a slightly lower sulfur
content for the treated material. Sulfur removal for this coal is,approximately the same
throughout the temperature range. Some benefit is exhibited in a long holding time at
1500°F. Material recovery, Figure 11, for the no-lime tests is better.
The calculated SO 2 emissions for these tests are given in Table 20. A heating
value was estimated at 12,500 Btu/lb. All of .the calculated values, both total sulfur and
pyritic plus organic sulfur, have emission values below the established limits.
43
-------
TABLE 15. ANALYSES OF PITTSBURGH SEAM COAL (PENNSYLVANIA MINE)
Coal
Pretreated Coal
+40 Mesh
Pretreated Coal
Proximate Analysis
Moisture
Volatile Matter
Ash
Fixed Carbon
Total
Ultimate Analysis (Dry)
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
3.0
26.0
33.3
37.7
100.0
34.34
52. 50
3. 54
1.35
1.08
7.19
100.00
0.3
19.7
35.3
44.7
100.0
35.41
52.10
2.94
1.23
1. 13
7.19
100.00
0.9
21.2
33.7
44.2
100.0
33.99
54. 10
3.26
1.11
. 1. 10
6.44
100.00
-------
TABLE 16. THERMOBALANCE RUN DATA, PITTSBURGH SEAM COAL (PENNSYLVANIA MINE)
Feed Coal*
Pretreated Coal*
Run No.
TB-76-Z5
TB-76-26
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
5 Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30
Feed
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1
.01
.44
.21
.35
.01
100
.01
.44
.21
.35
.01
.01
.44
.21
.35
.01
0.
0.
0.
0.
0.
00
34
16
41
91
0.
0.
0.
0.
0.
00
11
05
14
30
2:1
5
1300
30
Float Sink
0.
0.
0.
0.
0.
03 0.19
01 0.02
02 0.00
32 0.04
38 0.25
6. 1748
86.
13.
13.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
22
34
66
66
00
29
14
35
78
00
34
16
41
91
.8
0:1
5
1300
30
Feed
0.
0.
0.
0.
0.
00
34
16
41
91
Residue
0. 14
0.02
0.01
0.21
0.38
2.6015
0.9513 4. 5558
259.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
02
00
28
13
36
77
00
11
05
14
30
39.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
81
86
10.81
32.44
91 191. 11
01 0.36
00 0.04
01 0.00
13 0.08
15 0.48
00
00
02
32
34
.8
. 1
86.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
34
00
28
13
36
77
00
34
16
41
91
2.0446
21.41
21.41
67.86
0. 10
0.01
0.01
0. 14
0. 26
0.00
0.00
0.01
0.21
0.22
80. 5
85. 1
Calculated for 40 mesh fraction
B76091967
-------
TABLE 16. THERMOBALANCE RUN DATA,
PITTSBURGH SEAM COAL (PENNSYLVANIA MINE)
(Continued)
Feed Coal*
Pretreated Coal*
Run No.
Lime /Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
; Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-27
750
30
Feed
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1
.01
.44
.21
.35
.01
100
.01
.44
.21
.35
.01
.01
.44
.21
.35
.01
0.
0.
0.
0.
0.
00
34
16
41
91
0.
0.
0.
0.
0.
00
11
05
14
30
2:1
5
1400
30
Float
0. 10
0.00
0.02
0.24
0.36
TB-
-76-28
0:1
5
1400
30
Sink
0.23
0.01
0.00
0.02
0.26
4.4885
86.
13.
13.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
22
34
66
66
00
29
14
35
78
00
34
16
41
91
.8
259.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
02
00
28
13
36
77
00
11
05
14
30
0.8027 3.
10.
32.
2067
67
02
46.32 185.05
0.05
0.00
0.01
0.11
0.17
0.00
0-00
0.02
0.24
0.26
84.4
88.1
0.42
0.02
0.00
0.04
0.48
Feed
0.
0.
0.
0.
0.
00
34
16
41
91
Residue
0.06
0.04
0.03
0.22
0.35
2.9990
86.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
34
00
28
13
36
77
00
34
16
41
91
2. 3440
21.84
21.84
67.48
0.04
0.03
0.02
0. 15
0.24
0.00
0.00
0.03
0.22
0.25
77.9
83.2
B76091967
Calculated for 40 mesh fraction
-------
TABLE 16. THERMOBALANCE RUN DATA,
PITTSBURGH SEAM COAL, (PENNSYLVANIA MINE)
(Continued)
Feed Coat*
Run No.
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib '
i Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
0.01
0.44
0.21
0.35
1.01
100
0.01
0.44
0. 21
0.35
1.01
0.01
0.44
0.21
0.35
1.01
Pretreated Coal*
750
30
0.00
0.34
0. 16
0.41
0.91
86.34
13.66
13.66
0.00
0.29
0. 14
0.35
0. 78
0.00
0.34
0.16
0.41
0.91
22.8
TB-76-29
Feed
0.00
0.11
0.05
0.14
0.30
4.5260
259.02
0.00
0.28
0. 13
0.36
0.77
0.00
0. 11
0.05
0.14
0.30
2:1
5
1500
0
Float
0.05
0.02
0.01
0. 19
0.27
0.8005
45.81
0.02
0.01
0.00
0.09
0. 12
0.00
0.00
0.01
0. 19
0.20
88.3
91.1
Sink
0. 18
0.03
0.00
0.01
0.22
3.2325
184.99
0.33
0.06
0.00
0.02
0.41
TB-76-30
0:1
5
1500
0
Feed
0.00
0.34
0. 16
0.41
0.91
3.2010
86.34
0.00
0.28
0. 13
0.36
0.77
0.00
0.34
0. 16
0.41
0.91
Residue
0.22
0.00
0.00
0.16
0.38
2.4776
22.60
66.83
0. 15
0.00
0.00
0. 10
0.25
0.00
0.00
0.00
0.16
0. 16
87.0
90.1
Calculated for 40 mesh fraction
B76091967
-------
TABLE 16. THERMOBALANCE RUN DATA,
oo
PITTSBURGH SEAM COAL (PENNSYLVANIA MINE)
(Continued)
Feed Coal*
Pretreated Coal*
Run No.
Lime /Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
-; Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-31
750
30
JFeed^
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1
.01
.44
.21
.35
.01
100
.01
.44
.21
.35
.01
.01
.44
.21
.35
.01
0.
0.
0.
0.
0.
00
34
16
41
91
0.
0.
0.
0.
00
11
05
14
0.30
2:1
5
1500
30
Float
0.08
0.01
0.00
0.18
0.27
TB-76-32
0:1
5
1500
30
Sink
0.23
0.02
0.00
0.01
0.26
5.0231
86.
13.
13.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
34
66
66
00
29
14
35
78
00
34
16
41
91
259.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
02
00
28
13
36
77
00
11
05
14
30
22.8
0.8353
10.
32.
43.07
0.03
0.00
0.00
0.08
0.11
0.00
0.00
0.00
0.18
0.18
89.6
92. 1
3. 6388
93 _
79
187.64
0.43
0.04
0.00
0.02
0.49
Feed
0.
0.
0.
0.
0.
00
34
16
41
91
Residue
0.21
0.00
0.00
0.12
0.33
3.3107
86.34
0.
0.
0.
0.
0.
00
28
13
36
77
0.00
0.
0.
0.
0.
34
16
41
91
2. 5341
23.46
23.46
66.08
0. 14
0.00
0.00
0.08
0.22
0.00
0.00
0.00
0.12
0.12
89.6
92.1
B76091967
Calculated for 40 mesh fraction
-------
TABLE 16. THERMOBALANCE RUN DATA, PITTSBURGH SEAM COAL (PENNSYLVANIA MINE)
(Continued)
Feed Coal*
Pretreated Coal*
Run No.
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
VO Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
i Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-33
0.01
0.44
0.21
0.35
1.01
100
0.01
0.44
0.21
0.35
1.01
0.01
0.44
0.21
0.35
1.01
750
30
0.00
0.34
0. 16
0.41
0.91
86.34
13.66
13.66
0.00
0. 29
0. 14
0.35
0.78
0.00
0.34
0.16
0.41
0.91
22.8
Feed
0.00
0.11
0.05
0.14
0.30
4. 2900
259.02
0.00
0.28
0.13
0.36
0.77
0.00
0.11
0.05
0.14
0.30
2:1
20
1500
240,
Float
0.06
0.00
0.02
0.13
0.21
0.6934
11
34
41.86
0.03
0.00
0.01
0.05
0.09
0.00
0.00
0.02
0.13
0.15
92.2
94.1
TB-76-34
0:1
20
1500
Sink
0.25
0.02
0.00
0.01
0.28
3.1094
.36
.07
187.74
0.47
0.03
0.00
0.02
0.52
240
Feed Residue
0.00
0.34
0.16
0.41
0.91
2.8672
86.34
0.00
0.28
0.13
0.36
0.77
0.00
0.34
0.16
0.41
0.91
0.21
0.00
0.00
0.13
0.34
2.1344
25. 56
25.56
64.27
0.13
0.00
0.00
0.08
0.21
0.00
0.00
0.00
0. 13
0. 13
89.6
92.1
B76091967
Calculated for 40 mesh fraction
-------
Ln
O
3.0
25
2.0
1.5
tr
O WITH LIME
A WITHOUT LIME
D PRETREATED COAL
750 800 900 1000 1100 1200 1300
FINAL TEMPERATURE, °F
1400
1500
A7804IOIO
Figure 8. Treated material sulfur content, Pittsburgh seam, Pennsylvania coal.
-------
80
a
o
u
I 70
o>
- 60
tr.
ui
o
o
UJ
o:
o
o
o
UJ
LJ
tr
50
40
30
O WITH LIME
A WITHOUT LIME
O
O
I
1200
1300 1400
FINAL TEMPERATURE, °F
1500
A7804IOII
Figure 9- Treated material recovery, Pittsburgh seam, Pennsylvania coal.
-------
TABLE 17. SO2 EMISSIONS FOR THERMOBALANCE RUNS,
PRETREATED PITTSBURGH SEAM COAL
(PENNSYLVANIA MINE)
SO,/106 Btu
Pyritic and Organic
Test No. Total Sulfur Sulfur Only
TB-76-25 0.83 0.74
TB-76-26 0.83 0.48
TB-76-27 0.79 0.57
TB-76-28 0.76 0.55
TB-76-29 0.59 0.44
TB-76-30 0.83 0.35
TB-76-31 0.59 0.39
TB-76-32 0.72 0.26
TB-76-33 0.46 0.33
TB-76-34 0.74 0.28
Pretreated Coal 1.99 1.24
Raw Coal 2.21 1.22
52
-------
TABLE 18. ILLINOIS NO. 6 COAL ANALYSIS
440 Mesh
Coal Pretreated Coal Pretreated Coal
Proximate Analysis
Moisture
Volatile Matter
Ash
Fixed Carbon
Ul
W Total
Ultimate Analysis (dry)
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
1.3
37. 3
8.5
52. 9
100.0
8.63
74. 50
4. 91
2.77
1.49
7. 70
100.00
_*. in
0.4
28. 5
9.4
61.7
100.0
9.42
75. 20
4.30
2.16
1.66
7.26
100.00
1.6
27.6
8.8
62.0
100.0
8.98
74.80
4.29
2.34
1.55
8.04
100.00
-------
TABLE 19. THERMOBALANCE RUN DATA, ILLINOIS NO. 6 COAL
Feed Coal*
Pretreated Coal*
Run No.
Feed Ratio Lime/Coal
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
<-n Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-35
0. 00
0.01
0.99
1. 28
2. 28
100
100.00
0.00
0.01
0. 99
1. 28
2. 28
0. 00
0. 01
0. 99
1. 28
2. 28
750
30
0.01
0.01
0.63
1.39
2.04
90. 4
9.6
9.6
0.01
0.01
0. 57
1. 26
1.85
0.01
0.01
0.63
1.39
2.04
18. 9
Feed
0.00
0.00
0. 21
0.47
0.68
4. 3094
271. 20
0.01
0. 01
0. 57
1. 26
1.85
0.00
0.00
0.21
0.47
0.68
2:1
5
1300
30
Float Sink
0.04 0.39
0.00 0.06
0.02 0.00
0.39 0.04
0.45 0.49
!»-»/
1 £ T n
63.79 174.16
0.03 0.68
0.00 0.10
0.01 0.00
0.25 0.07
0.29 0.85
0.02
0. 39
0.41
85. 9
88.6
TB-76-36
0:1
5
1300
30
Feed
0.01
0.01
0.63
1.39
2.04
2. 4850
90.4
0.01
0.01
0. 57
1.26
1.85
0.01
0.01
0.63
1. 39
2.04
Residue
0.05
0.00
0.00
0.41
0.46
1. 7840
28. 21
28. 21
64. 90
0.03
0.00
0.00
0. 27
0. 30
0.00
0.41
0.41
85.4
88. 2
*Calculated for +40 mesh fraction.
-------
TABLE 19. THERMOBALANCE RUN DATA, ILLINOIS NO. 6 COAL (Continued)
Feed Coal*
Pretreated Coal*
Run No.
Feed Ratio Lime /Coal
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g ,
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
0. 00
0.01
0. 99
1. 28
2. 28
100
100.00
0.00
0.01
0. 99
1. 28
2. 28
0.00
0.01
0. 99
1. 28
2. 28
750
30
0.01
0.01
0.63
1. 39
2. 04
90. 4
9.6
9.6
0.01
0.01
0. 57
1. 26
1.85
0.01
0;01
0.63
1. 39
2.04
18. 9
Feed
0.00
0.00
0.21
0.47
0.68
4. 3980
271. 20
0.01
0.01
0. 57
1.26
1.85
- -
0.00
0.00
0.21
0.47
0.68
1±J- 10-31
2:1
5
1400
30
Float Sink
0.03 0.43
0.01 0.07
0.02 0.00
0.32 0.05
0.38 0.55
12. 52
37.57
63.49 173.75
0.02 0.75
0.01 0.12
0.01 0.00
0.20 0.09
0. 24 0. 96
0.02
0. 32
0. 34
88.6
90.8
IB'
- fO JO
0:1
5
1400
30
Feed
0.01
0.01
0.63
1.39
2.04
2.6045
90.4
0.01
0.01
0.57
1.26
1.85
0.01
0.01
0.63
1.39
2.04
. .Residue
0.04
0.00
0.00
0.40
0.44
1.8330
29.62
29.62
63.62
0.03
0.00
0.00
0.25
0.28
0.00
0.40
0.40
86.5
89.0
^Calculated for +40 mesh fraction.
-------
TABLE 19. THERMOBALANCE RUN DATA, ILLINOIS NO. 6 COAL (Continued)
Feed Coal*
Pretreated Coal*
Run No.
Feed Ratio Lime/Coal
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
np_ t_ 1 1iir_; *»!. i.
j. ocai w eignc
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30
Feed
0
0
0
1
2
100
0
0
0
1
2
0
0
0
1
2
. 00
.01
. 99
. 28
. 28
100
. 00
.00
.01
. 99
. 28
. 28
.00
.01
. 99
. 28
. 28
0.
0.
0.
1.
2.
01
01
63
39
04
0.
0.
0.
0.
0.
00
00
21
47
68
TB-76
-39
TB-76-40
2:1
5
1500
0
Float Sink
0.
0.
0.
0.
0.
05 0. 13
05 0.12
02 0.00
34 0. 07
46 0. 32
4.4136
90
9
0.
0.
0.
1
1.
0.
. 4
_
.6
01
01
57
26.
85
01
0.01
0.
1.
2.
63
12
04
Feed
0.
0.
0.
1.
2.
01
01
63
39
04
0:1
5
1500
0
Residue
0. 04
0. 00
0.02
0.41
0.47
2. 5319
1.0251 2.8346
271.
0.
0.
0.
1.
1.
0.
0.
0.
0.
0.
20
01
01
57
26
85
00
00
21
47
68
62.
0.
0.
0.
0.
0.
0.
0.
0.
1 "* e, ^
1*7 fi A
99 174.17
03 0. 23
03 0. 21
01 0.00
21 0.12
30 0. 56
02
34
36
90
0.
0.
0.
1.
1.
0.
0.
0.
1.
2.
. 4
01
01
57
26
85
01
01
63
39
04
88. 1
18
. 9
90.4
1. 7761
7O Q ^
£.7. O 3
29. 85
63.42
0. 03
0.00
0. 01
0. 26
0. 30
0.02
0.41
6.43
85.4
88. 2
"Calculated for +40 mesh fraction.
-------
TABLE 19. THERMOBALANCE RUN DATA, ILLINOIS NO. 6 COAL (Continued)
Ul
Feed Coal*
Pretreated Coal*
Run No.
Feed Ratio Lime/Coal
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
0. 00
0.01
0. 99
1. 28
2.28
100
100.00
0.00
0.01
0. 99
1. 28
2. 28
0.00
0.01
0. 99
1. 28
.2. 28
750
30
0.01
0. 01
0.63
1.39
2. 04
90.4
9.6
9.6
0. 01
0.01
0. 57
1. 26
1. 85
0.01
0.01
0.63
1. 39
2.04
18. 9
Feed
0. 00
0. 00
0. 21
0.47
0.68
4. 3986
271. 20
0. 01
0.01
0. 57
1. 26
l: 85
0. 00
0. 00
0. 21
0.47
0.68
TB-76-41
2:1
5
1500
30
Float Sink
0.06 0. 13
0.03 0.14
0.02 0.00
0.34 0.02
0.45 0.29
1 3 04 '
in 11
55.05 180.79
0.03 0.24
0.02 0.25
0.01 0.00
0.19 0.04
. .0. 25 0. 53
0.02
0. 34
0. 36
89. 2
91.2
TB-76-42
0:1
5
1500
30
Feed
0.01
0.01
0.63
1. 39
2.04
2. 4049
90.4
0.01
0.01
0. 57
1. 26
1.85
0.01
0. 01
0.63
1. 39
2.04
Residue
0.04
0.00
0.03
0. 37
0.44
1.6678
30.65
30.65
62.69
0.03
0.00
0.02
0. 23
0. 28
0.03
0.37
0.40
86. 5
89.0
^-Calculated for +40 mesh fraction.
-------
TABLE 19. THERMOBALANCE RUN DATA, ILLINOIS NO. 6 COAL (Continued)
Feed Coal*
Pretreated Coal*
Run No.
Feed Ratio Lime/Coal
Heating Rate, F/min
Terminal Temperature, I
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
<£ Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-43
r
0
0
0
1
2
750
30
. 00
.01
. 99
. 28
. 28
100
0.
0.
0.
1.
2.
01
01
63
39
04
2:1
20
1500
240
Feed
0.00
0.
0.
0.
0.
00
21
47
68
Float Sink
0.
0.
0.
0.
0.
04 0. 10
00 0.13
03 0.00
24 0.06
31 0. 29
4. 2878
90
. 4
9.6
9.6
100
0
0
0
1
2
0
0
0
1
2
.00
. 00
. 01
99
. 28
. 28
. 00
.01
. 99
. 28
. 28
0.
0.
0.
1.
1.
0.
0.
0.
1.
2.
18
01
01
57
26
85
01
01
63
39
04
. 9
271.
0.
0.
0.
1.
1.
0.
0.
0.
0.
0.
20
01
01
57
26
85
00
00
21
47
68
53.
0.
0.
0.
0.
0.
0.
0.
0.
91
i A no
At t A
52 179.49
02 0.18
00 0. 23
02 0.00
13 0.11
17 0.52
03
24
27
. 9
TB-76-44
0:1
20
1500
240
Feed
0.01
0.
0.
^
2.
01
63
li
04
Residue
0.07
0.00
0.03
0.26
0.36
2. 3421
90.
0.
0.
0.
1.
1.
0.
0.
0.
1^
2.
84
01
01
57
26
85
01
01
63
_39
04
93.4
1.6189
30.88
30.88
62.78
0.04
0.00
0.02
0.16
0.22
0.03
0.26
0.29
90. 3
92.1
*Calculated for +40 mesh fraction.
£3760920 12
-------
vo
O WITH LIME
A WITHOUT LIME
D PRETREATED COAL
750 800
FINAL TEMPERATURE, "F
Figure 10. Treated material sulfur content, Illinois No. 6 coal.
-------
75
o
8
o
.E 70
.21
o
H-
o
65
o:
ui
3
o
UJ
a:
g
o
o
UJ
UJ
tr
60
55
50
O WITH LIME
A WITHOUT LIME
A
O
O
O
1200
1300
1400
FINAL TEMPERATURE,°F
1500
A7804IOI3
Figure 11. Treated material recovery, Illinois No. 6 coal.
-------
TABLE 20. SO2 EMISSIONS FOR THERMOBALANCE RUNS,
PRETREATED ILLINOIS NO. 6 COAL
Test No.
TB-76-35
TB-76-36
TB-76-37
TB-76-38
TB-76-39
TB-76-40
TB-76-41
TB-76-42
TB-76-43
TB-76-44
Pretreated Coal
Raw Coal
Ib
Total Sulfur
0.72
0. 74
0.61
0.70
0. 74
0.75
0.72
0. 70
0. 50
0. 58
3.13
3.41
SO2/106 Btu -
Pyritic and Organic
Sulfur Only
0.66
0. 66
0.54
0.64
0. 58
0.69
.0. 58
0.64
0.43
0.46
3.10
3.39
61
-------
EFFECT OF HEAT-UP RATE
Some rapid heat-up tests were made with pretreated Western Kentucky No. 9 coal
in the thermobalance. Effects of rapid heating rate and prolonged residence times on
sulfur removal, with and without lime, were studied. The rapid heat-up is accomplished
by lowering the basket into the zone that is at 1500°F, rather than lowering it and then
applying heat.
These runs (TB-76-21 through TB-76-24, Table 21) all show good sulfur reduction
and nearly the same weight loss. The recovery is higher for treated material in the no-
lime tests.
A graph of the sample weight loss as it is heated to 1500°F is shown in Figure 12.
The curve is divided into three sections: A, B, and C. Section A is the weight loss'
observed while the sample is in the cool zone. This loss is caused by convection heating
from the hot zone below the basket; the weight loss is the moisture removed in this time
period. Section B is the weight loss as the sample is lowered into the heated zone;
section C is the weight loss during the holding time. Although the curves differ, the final
point is essentially the same regardless of the heating rate.
Pretreated Western Kentucky No. 9 coal without lime was used in additional
thermobalance tests with rapid heat-up to determine the effect of shortened soaking
time. The samples were rapidly heated to 1500°F and soaked at that temperature for
15, 30, 60, and 90 minutes.
Figure 13 shows the weight loss with respect to residence time in the heated zone.
The initial broken line is attributed to weight loss by moisture reduction as the unit is
heated up. When the heated zone reaches 1500°F, the sample basket is lowered into it.
The majority of the weight loss occurs in the first 24 seconds as the basket is lowered
and positioned in the hot zone. Only slightly more weight loss is recorded at the end of
15 minutes and essentially none after this, up to 120 minutes.
The results for these tests, TB-76-45 through TB-76-48, are shown in Table 22. A
previous run, TB-76-24, with rapid heat-up and 120-minute residence time is included for
comparison. The tests show decreasing total sulfur with increased holding time at
1500°F. The pyritic sulfur content is reduced to nearly zero by the end of 15 minutes.
The organic sulfur reduction is directly dependent upon residence time at temperature.
Material recovery is reduced as the time increases.
Figure 14 illustrates the sulfur reduction achieved in the tests. As mentioned, the
organic sulfur and total sulfur decrease as residence time increases. The SO, emissions
for the tests are shown in Table 23. The heating value was estimated at Il,5o5 Btu/lb.
A residence time of 60 minutes yields a borderline SO2 emission, while longer times are
acceptable, considering total sulfur. All tests are within limits if only pyritic and
organic sulfur are used.
Based on these data, the coal can be heated rapidly to 1500°F, as by injection into
a fluidized bed. A residence time of 15 to 60 minutes is sufficient for reduction of sulfur
to acceptable emission limits.
62
-------
TABLE 21. THERMOBALANCE RUN DATA, PRETREATED WESTERN KENTUCKY NO. 9 COAL
Feed Coal Pretreated Coal
Run No.
Feed Ratio, lime /coal
Coal
Heating Rate, F/min.
Terminal Temperature, F
Holding Time, min.
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, gm
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
*Sample was lowered rapidly
0. 02
0. 52
0. 92
1. 57
3. 03
100
0. 02
0. 52
0. 92
1. 57
3.03
0. 02
0. 52
0. 92
1. 57
3.03
into reaction zone at 1 500 F.
750
30
0.01
0. 10
1. 25
1. 29
2.65
90. 84
9.16
9.16
90. 84
0.01
0. 09
1. 13
1. 17
2.40
0.01
0. 10
1. 25
1. 29
2.65
20. 5
TB-76-21
TB-76-22
Feed
0.00
0. 03
0.42
0.43
0.88
4. 0566
272. 52
0.01
0.09
1. 13
1. 17
2.40
0.00
0. 03
0.42
0.43
0. 88
2:1 0:1
Pret. W. Ky. No. 9
20
1500
120
Float
0. 13
0.00
0.03
0. 29
0.45
Sink
0. 97
0.03
0.00
0.05
1.05
0.7146 2.7864
13. 70
41. 10
48.00 187.18
0.06
0.00
0.01
0. 14
0. 22
0.03
0. 29
0. 32
93.75
93.05
1.82
0.06
0.00
0.09
1.97
20
1500
120
Feed Residue
0.01
0. 10
1. 25
1. 29
2.65
2.6063
90. 84
0.01
0.09
1. 13
1. 17
2.40
0. 01
0. 10
1.25
1.29
2.65
0. 22
0.01
0.01
0. 19
0.43
1.7699
32.09
32.09
61.69
0.13
0.01
0.01
0.12
0. 27
0.01
0. 19
0. 20
94. 58
95. 71
-------
TABLE 21. THERMOBALANCE RUN DATA, PRETREATED WESTERN KENTUCKY NO. 9 COAL
(Continued)
Feed Coal
Pretreated Coal
Run No.
Feed Ratio, lime/coal
f*r»a 1
^*oai
Heating Rate, F/min.
Terminal Temperature, F
Holding Time, min.
Sulfur, wt <7»
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, grri
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight. Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
*Sample was lowered rapidly
0
0
0
1
3
0
0
0
1
3
0
0
0
1
3
W-\r . . TVT_ q
. 02
. 52
. 92
. 57
. 03
100
. 02
. 52
. 92
. 57
. 03
. 02
. 52
.92
. 57
.03
750
30
0.
0.
1.
1.
2.
90.
9.
9.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
2.
20
01
10
25
29
65
84
16
16
84
01
09
13
17
40
01
10
25
29
65
. 5
into reaction zone at 1 500 F.
TB-76-23 TB-76-24
0:1
To. 9 :
Rapid Heating*
1500
120
Feed Residue
Feed
0.00
0.03
0.42
0.43
0.88
2:1
T~* r n t
Rapid Heating*
1500
120
Float
0. 13
0. 00 .
0. 03
0. 16
0. 32
Wlf
. t\
Sink
1.09
0.03
0.00
0.05
1. 17
4. 2964
272. 52
0.01
0.09
1. 13
1. 17
2.40
0.00
0.03
0.42
0.43
0. 88
0.8022 2
13.60
40. 79
. 9100
50.88 184.57
0.07
0.00
0.01
0.08
0. 16
0.03
0.16
0. 19
96. 25
97. 03
2.01
0.06
0.00
0.09
2.16
0.01
,0. 10
1. 25
1. 29
2.65
2. 5892
90.84
0.01
0.09
1.13
1.17
2.40
0.01
0.10
1.25
1.29
2.65
0.13
0.00
0.02
0. 14
0. 29
1.7646
31.85
31.85
61.91
0.08
0.00
0.01
0.09
0.18
0. 02
0. 14
0. 16
95.83
96.70
-------
3.0
2.5
2.0
v>
0>
1.5
UJ
1.0
1500, RAPID, I20min.
NO LIME
1500,20,120mln.
NO LIME
1500, RAPID. 120 mln.
2«l LIME/COAL
0.5
PRET.W.Kg.No.9
TB-76-2lto24
AS BASKET IN COOL ZONE
B= BASKET BEING LOWERED
INTO REACTION ZONE ~~
C= BASKET IN REACTION ZONE
1300, 5,30miiw
Z-1 LIME/COAL
(SHOWN FOR
COMPARISON)
TB-76-1
)0,20.120 mln.
M LIME/COAL
200
400
600 800 1000
TEMPERATURE, °F
1200
1400 1600 1800
A7606I268
Figure 12. Thermobalance sample weight loss.
-------
I.I
1.0
0.9
0.8
§0.6
o:
LJ
0.4
0.3
0.2
0.1
TB-76-24
TB-76-48TB-76-47
TB-76-46
TB-76-45
HEATUP
15 30
>4 SECONDS TO LOWER
BASKET INTO HOT ZONE
60 90
HOLDING TIME, min.
A76O9I9II
120
Figure .13. Thermobalance runs, data on pretreated Western Kentucky No. 9 coal.
-------
TABLE 22.
THERMOBALANCE RUN DATA, WESTERN
(RAPID HEAT-UP RATE)
Feed Coal* Pretreated Coal*
KENTUCKY NO. 9 COAL
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, F/min
o
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
O"> Total Weight
Coal Weight
Reduced Data
Wright, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-24
0
0
0
1
3
0
0
0
I
3
0
0
0
1
3
. 02
. 52
. 92
. 57
. 03
100
. 02
. 52
. 92
. 57
.03
. 02
. 52
.92
. 57
. 03
Ky. No. '
7
0.
0.
1.
1.
2.
50
30
01
10
25
29
65
0:1
Rapid Heating
1500
120
Feed Residue
0.
0.
1.
1.
2.
01
10
25
29
65
0.13
0.00
0.02
0. 14
0. 29
2. 5892
90.
9.
9.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
2.
20
84
16
16
84
01
09
13
17
40
01
10
25
29
65
. 5
90.
0.
0.
1.
1.
2.
0.
0.
1.
!_._
2.
84
01
09
13
17
40
01
10
25
29
65
1. 7646
31. 85
31. 85
61. 91
0.08
0.00
0.01
0. 09
0. 18
0.02
0. 14
0. 16
95. 8
.96.7
TB-76-45
Pretreated
Rapid
1
Feed
0.01
0. 10
1. 25
1.29
2.65
2. 9610
90. 84
0.01
0.09
1. 13
1. 17
2.40
0.01
0. 10
1. 25
1.29
2.65
0:1
W. Ky. No
Heating
500
90
Residue
0. 23
0.00
0.02
0. 32
0. 57
2. 0686
30. 14
30. 14
63.46
0. 15
0.00
0.01
0. 20
0. 36
0.02
0. 32
0. 34
91.3
93.1
TB-76-46
0:1
Rapid Heating
1500
60
Feed Residue
0.01
0. 10
1.25
1.29
2.65
2. 8700
90.84
0.01
0.09
1. 13
1. 17
2.40
0.01
0. 10
1. 25
1.29
2.65
0. 23
0.01
0.02
0.46
0.72
2.0121
29. 89
2.9.89
63.69
0.15
0.01
0.01
0.29
0.46
0.02
0.46
0.48
87. 5
90. 1
*Calculated for +40 mesh.
-------
TABLE 22.
oo
THERMOBALANCE RUN DATA,
(RAPID HEAT-UP
Feed Coal* Pretreated Coal*
WESTERN KENTUCKY NO. 9 COAL
RATE) (Continued)
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content. %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
TB-76-47
0
0
0
1
3
0
0
0
1
3
0
0
0
1
3
. 02
. 52
-92
. 57
.03
100
. 02
. 52
.92
. 57
.03
. 02
. 52
. 92
. 57
. 03
Ky. No.
7
0.
0.
1.
1.
2.
50
30
01
10
25
29
65
I
T
Rapid
1
Feed
0.
0.
1.
1.
2.
01
10
25
29
65
TB-76-48
0:1
'retreated W. Ky. No. 9
Heating Rapid
500 1
30
Residue Feed
0.
0.
0.
0.
1.
41
01
02
57
01
2.7170
90.
9.
9.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
2.
84
16
16
84
01
09
13
17
40
01
10
25
29
65
0.
0.
1.
1.
2.
01
10
25
29
65
0:1
1 Heating
500
15
Residue
0. 50
0.02
0.00
0.68
1.20
2. 5688
1.9329
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
2.
84
01
09
13
17
40
01
10
25
29
65
28.
28.
64.
0.
0.
0.
0.
0.
0.
0.
0.
86
86
62
26
01
01
37
65
02
57
59
90.
0.
0.
1.
1.
2.
0.
0.
1.
1 .
2.
84
01
09
13
17
40
01
10
25
11
65
84. 2
20. 5
87. 5
1.8493
28.00
28.00
65.40
0.33
0.01
0.00
0.44
0.78
0.00
0.68
0.68
81^7
85. 5
*Calculated for +40 mesh.
B76092055
-------
OA-RAW COAL-
10
20
-------
TABLE 23. SO2 EMISSIONS AND HEATING VALUES FOR
WESTERN KENTUCKY NO. 9 COAL
(RAPID HEAT-UP RATE)
i rearaneirc
Conditions
(Test No. )
Coal (dry)
Pretreated +40 mesh
750°F;, 30 min
1500°F, 15 min
(TB-76-48)
1500°F, 30 min
(TB-76-47)
1500°F, 60 min
(TB-76-46)
1500°F, 90 min
(TB-76-45)
1500°F, 120 min
(TB-76-24)
1500°F, 330 min
Btu/lb
12,454
11,809
11,565
11,565
11,565
11,565
11,565
11,565
Total
5.62
5. 18
2. 07
1.74
1.24
0. 98
0. 50
0.66
Pyritic and
Organic
4.63
4.49
1.17
1.02
0.83
0. 5.9
0.28
0.28
Total Heating Value,
Btu/100 Ib Coal Feed
1,245,400
1,072,730
756,351
747,330
736,575
733,915
715,989
717,146
(BR-76-7)
Note: EPA limit for SO2 emissions = 1.2 Ib SO2/106 Btu.
70
-------
LABORATORY-SCALE TEST CONCLUSIONS
The data obtained from the thermobalance reactor support the following conclusions:
Four Eastern U.S. coals have been satisfactorily hydrodesulfurized. These coals included run-of-mine coal,
high-ash coal, high-sulfur coal, and both mid-continent and Appalachian coals.
Pretreatment of the coals is required for satisfactory sulfur removal.
The use of the lime sulfur-getter is not imperative; coal recovery is greater if lime is not used.
Rapid heat-up is satisfactory for sulfur removal.
Temperatures of 1400° to 1500°Fare desirable with a total reaction time of over 60 minutes.
71
-------
BENCH-SCALE TEST WORK - HYDRODESULFURIZATION
WESTERN KENTUCKY NO. 9 COAL RUNS
Slow Heat-Up Runs
Data for test runs with slow heat-up rate with pretreated Western Kentucky No. 9
coal are shown in Tables 24 through 26. The pretreated coal was screened at +40 mesh so
that the size consist would be the same as in the thermobalance runs. The lime used was
60+80 mesh for compatible fluidization characteristics and so that a screen separation
of treated material could be made at +50 mesh. Analyses for the coal, pretreated coal,
and +40 mesh pretreated coal are shown in Table 24.
Table 25 lists laboratory data and reduced data. Values for coal and pretreated
coal have been back-calculated to show only +40 mesh materials because of the uneven
sulfur distribution. The reduced data for the tests using lime were calculated for both
screen and float-sink separation. Treated material was split into two parts by riffling.
One part was screen separated and the other float-sink separated. To put all data on the
same basis, the fractions were treated as if they were from the entire sample. For
example, assume 150 grams of mixture were initially charged, and 125 grams remained
after treatment. This material is split into two parts by riffling. One part is separated
by 50 mesh screening and the percentages of +50 and 50 mesh material recorded. These
percentages are used to determine how the total 125 grams would have separated and the
reduced data calculated accordingly. The same procedure is used for the float-sink
separation results in calculations. In this way, each lime/coal mixture run yielded not
only a comparison with the no-lime runs, but the separation techniques as well.
Identical conditions were used in each pair of experiments, one with coal only and
the other with the lime/coal mix. Heating rate, terminal temperatures, and holding
times were varied as shown in Table 25. Comparison of the pairs shows that the no-lime
tests have higher total sulfur values (less complete removal) than the lime tests. Part of
this can be attributed to the removal of the sulfide-type sulfur in the separation
processes. The reduced data on pyritic and organic sulfur removal do not exhibit as large
a difference. Treated material recovery is higher in all the coal-only tests than either of
the separation techniques for the lime test.
Contrary to the thermobalance data for this coal, reported earlier, sulfur removal
appears to be better in tests using the coal/lime mixture. The reason may be in more
intimate contact and mixing in the fluidized condition of the batch reactor, as compared
with the thermobalance stagnant material conditions. Other factors, such as amount of
material handled, gas requirements for treatment of the lime and coal mix, and the
separation facilities, favor operation without lime.
Table 26 gives the calculated SO^ emissions and product heat recovery from the
treated coal. On this basis, only the first pair of runs shows a large difference in SO^
72
-------
TABLE 24. ANALYSIS OF BATCH REACTOR RUNS WITH WESTERN KENTUCKY NO. 9 GOAL
OJ
Proximate Analysis
Moisture
Volatile Matter
Ash
Fixed Carbon
Total
Ultimate Analysis
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
Coal
5.8
36. .3
10.6
47. 3
100.0
1 1 . 24
70.00
4. 54
3.74
1.53
8. 95
100.00
Pretreated Coal
0.8
27.7
11.2
60. 3
100.0
11,25
71.40
4.06
3.16
1.64
8.49
100.00
+40 Mesh
Pretreated
Coal
1.6
26.7
14.1
57.6
100.0
14.31
67.80
3.84
3.23
1.48
9.34
100.00
-------
TABLE 25.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN
KENTUCKY NO. 9 COAL
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
^Calculated for 40 mesh fraction.
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal*
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
y. No. 9 -
7
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
50
0
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
.6
BR-76-1
0:
1
5
1400
30
Feed Residue
0.
0.
1.
1.
3.
1
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
50
84
04
09
40
25
78
04
10
54
38
06
0.42
0.00
0.02
0. 81
1. 25
109.8
26. 8
26. 8
66. 49
0. 30
0.00
0.01
0. 54
0.85
0. 02
0. 81
0.83
80. 2
84. 3
itreated W.
Feed
0. 01
0.03
0. 52
0.46
1.02
150
272. 52
0.04
0.09
1.40
1. 25
2. 78
0.01
0.03
0. 52
0.46
1.02
Ky. No.
+ 50
0. 11
0.01
0.02
0. 30
0.44
61. 39
0.07
0.01
0.01
0. 18
0. 27
0.02
0.30
0. 32
93. 2
94.6
BR-76-2
2:1
5
1400
30
-50 Float
1.01 0.
0.04 0.
0.00 0.
0.06 0.
1.11 0.
168.26 57.
1.70 0.
0.07 0.
0.00 0.
0.10 0.
1.87 0.
0.
0.
0.
98
98
05
01
01
06
13
97
03
01
01
03
08
01
06
07
.6
.9
Sink
1.02
0.04
0.00
0.21
1.27
171.68
1.75
0.07
0. 00
0. 36
2.18
-------
TABLE 25.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN
KENTUCKY NO. 9 COAL (Continued)
Run No.
Lime'Coal Feed Ratio
C«a1
Oal
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt "],
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, 1,
Total Weight
. Coal Weight
Reduced Data
Weight. Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic.
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic .
Total.
Sulfur Removal, wt %
From Feed
From Coal
'Calculated for 40 mesh fraction.
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00 '
02
60
06
82
50
02
60
06
82
50
'+40 Mesh
Feed Coal' Pretreated Coal
W. Ky. No. 9
750
30
0. 04
0. 10
1.'54
1. 38
3. 06
90. 84
9. 16
' 9. 16
0. 04
0. 09
1. 40
1. 25
2. 78
0. 04
0. 10
1. 54
1. 38
3. 06
20. 6
BR-76-3
0:1
T
Feed
0.04
0. 10
1. 54
1.38
3.06
75.0
90. 84
0.04
0.09
1.40
1.25
2.78
0.04
0. 10
1. 54
1. 38
3.06
5
1500
30
Residue
0.12
0.00
0.02
0. 37
0. 51
51.7
31.1
31.1
62.62
0.08
0.00
0.01
0. 23
0. 32 ,
0. 02
0. 37
0. 39
91.4
93.1
BR-76-4 .
ated
W Ky
Feed
0.
0.
0.
0,
1.
1
272.
0.
0.
1.
1.
2.
0.
0,
0.
0.
1.
01
03
52
46
02
50
52
04
09
40
25
78
01
P.3
52
46
02
No 9
+50
0. 22
0. 01
0. 02
0. 17
0. 42
53. 17
0. 12
0. 01
0. 01
0. 09
0. 23
0. 02
0. 17
0. 19
96.4
97. 1
2:1
5
1500
30
-50 Float
1. 29 0.
0.05 0.
0.00 0.
0. 04 0.
. 1. 38 0.
1 R 7
r/ 7
168. 29 49.
2.17 0.
0. 08 0.
0.00 0.
0.07 0.
2. 32 0.
0.
0.
0.
10
00
01
32
43.
68
05
00
01
16
22
01
32
33
Sink
1. 30
0. 03
0. 00
0.08
1.41
171. 78
2. 23
0. 05
0. 00
0. 14
2. 42
93. 9
95.1
-------
TABLE 25.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN
KENTUCKY NO. 9 COAL (Continued)
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate. °F'min
Terminal Temperature. F
Holding Time, min
Feed
Coal"
+40 Mesh
Pretreated Coal
f. No. 9 -
7
3
50
0
BR-76-5
0
:1
20
1500
240
Feed
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, «,
Total Weight
Coal Weight
Reduced Data
Weight. Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
i
0.
0.
1.
1.
3.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
75
84
04
09
40
25
78
04
10
54
38
06
20. 6
Residue
0. 26
0. 01
0. 02
0. 27
0. 56
41. 3
44. 93
44. 93
50. 02
0. 13
0. 01
0. 01
0. 14
0. 29
--
--
0.02
0. 27
0. 29
94.6
95.7
ted W. Ky. Nc
Feed
0.01
0.03
0. 52
0.46
1.02
150
272. 52
0.04
0. 09
1. 40
1. 25
2. 78
0.01
0.03
0. 52
0.46
1.02
+50
0. 13
0.00
0.00
0.09
0. 22
53. 96
0.07
0.00
0.00
0.05
0. 12
--
--
0.00
0.09
0.09
98. 2
98.6
BR-76-6
2:1
20
1500
240
-50 Float
1.02 0.06
0.01 0.01
0.00 0.03
0.02 0.19
1.05 0.29
162.97 48.01
1.66 0.03
0.02 0.00
0.00 0.01
0.03 0.09
1.71 0.13
--
--
0.03
0. 19
0.22
96.4
97. 1
Sink
0. 95
0.03
0.00
0.02
1.00
168. 92
1.60
0.05
0.00
0.03
1.68
*Calculated for 40 mesh fraction.
-------
TABLE 25.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN
KENTUCKY NO. 9 COAL, (Continued)
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, F'min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, ?,
-J Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
. Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal*
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
y. No. 9 -
7
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
50
0
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
. 6
BR-76-21
0:1
5
1400
60
Feed Residue
0.
0.
1.
1.
3.
75.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
00
H4
04
09
40
25
78
04
10
54
38
06
0. 20
0.01
0. 03
0. 35
0. 59
52. 5
30. 0
30.0
6.3. 59
*
0. 13
0.01
0. 02
0. 22
0. 38
--
--
0.03
0. 35
0. 38
91. 4
93.1
reated'W. Ky. No. 9
Feed +50
0.01
0.03
0. 52
0.46
1.02
150
272. 52
0. 04
0.09
1. 40
1. 25
2. 78
0.01
0.03
0. 52
0.46
1.02
0. 10
0. 00
0.02
0. 20
0. 32
54. 13
0.05
0.00
0. 01
0. 11
0. 17
--
--
0.02
0. 20
0. 22
95.7
96.6
BR-76-22
2:1
5
1400
60
-50 Float
1.08 0.
0.07 0.
0.00 0.
0.16 0.
1.31 0.
1 1 tl rt
05
03.
02
20
30
163.52 55.5
1.77 0.
0.11 0.
0.00 0.
0. 26 0.
2. 14 0.
0.
0.
0.
95
96
03
02
01
11
17
--
--
02
20
22
. 7
.6
Sink'
1.45
0.08
0.00
0.04
1. 57
162. 16
2. 35
0.13
0.00
0.06
2. 54
'Calculated for 40 mesh fraction.
-------
TABLE 25.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN
KENTUCKY NO. 9 COAL (Continued)
Run No.
Lime /Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Weight Loss, 1,
00 Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
* Calculated for 40 mesh fraction.
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal*
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
750
30
0.
0.
1.
1.
3.
90
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
BR-76-23
0:1
5 .
1300
60
Feed Residue
0.04
0. 10
1. 54
1.38
3.06
75.00
90.84
0.04
0.09
1.40
1. 25
2.78
0.04
0. 10
1. 54
1. 38
3.06
20. 6
0. 28
0.02
0.02
0. 74
1.06
28. 9
28. 9
64. 59
0. 18
0.01
0.48
0.01
0.68
--
--
0.02
0.74
0.76
82.4
86.0
Feed
0. 01
0. 03
0. 52
0. 46
1. 02
150
272. 52
0.04
0.09
1.40
1. 25
2. 78
0. 01
0.03
0. 52
0.46
1.02
BR-76-24
2:1
5
1300
60
+50 -50 Float
0. 20
0.01
0. 03
0. 36
0. 60
57. 17
0. 11
0.01
0.02
0. 21
0. 35
--
--
0.03
0. 36
0. 39
91.7
93.4
0.61 0.
0. 08 0.
0. 00 0.
0. 22 0.
0. 91 0.
146.13 54.
0. 89 0.
0.12 0.
0. 00 0.
0. 32 0.
1. 33 0.
0.
0.
0.
90
09
04
01
46
60
-
89
05
02
01
25
33
--
--
01
46
47
.6
Sink
1. 04
0.06
0.00
0.08
1.18
148.41
1. 54
0.09
0. 00
0.12
1. 75
92.6
-------
TABLE 26. BATCH REACTOR -TEST FOR SO2 EMISSIONS AND
HEATING VALUES, WESTERN KENTUCKY. NO. 9 COAL
Ib S02/106 Btu
Coal (Dry)
Pretreated +40 Mesh
BR-76-1 Residue
BR-76-2 +50
Float
BR-7,6-3 Residue
BR-76-4 +50
Float
BR-76-5 Residue
BR-76-6 +50
Float
BR-76-12 Residue
BR-76-.22 +50
Float
BR-76-23 Residue
BR-76-24 +50 .
Float
Btu/lb
12,454
11,809
12,119
12,107
12,684
11,967
11,035'
12,134 ""
11,651
11,463
12,029.
11,810
10,856 ,
12,149
11,859
10,270. '
11,214
Total
5.62
5.18
2.06
0.73
0.20
0.85
0.76
0.71
0.96
0.38
0.48
0-99
0.59"
0.49
1.79
1.17
.1.07
Pyritic &
Organic
4.63
4.49
1.37
0.53
0.11
0.65
0.34
0.54
0.50
0.16
0.37
0.64
0.41
0.36
1.28
0.76
0.84
Total Heating Value,
Btu/100 Ib coal feed
1,245,400
1,072,730
805,792
743,249
735,291
749,374
586,731
602,817
582,783
618,543
577,512
750,998
587,635
674,270
765,973
587,136
615,536
79
-------
emissions between the lime and no-lime tests. Considering total sulfur, only BR-76-1 and
BR-76-23, the lower temperature runs, have emissions that exceed the allowable limit.
All the other runs are below the standards even when total sulfur is considered. The
higher recovery of material in the no-lime tests will, help offset any differences in sulfur
removal^ because of greater heating value yields.
i
Figure 15 shows the sulfur content of the treated Western Kentucky No. 9 coal in
both the thermobalance and the batch-reactor runs. Although the initial sulfur contents
of the feed coals differ slightly, both test series show good sulfur removal.
Rapid Heat-Up Runs
A series of runs with pretreated Western Kentucky No. 9 coal was made in the
batch reactor using heat-up rates over 60°F/niin (Table 27). This was accomplished by
heating the furnace to near 1500°F and then placing the reactor into it. Residence time
at the final temperatures was varied from 30 to 330 minutes.
The first two tests, BR-76-7 and BR-76-8, (one with lime acceptor and one
without) were held for 5-1/2 hours at the terminal temperature. This represents total run
times of equal length for the rapid and slow heat-up tests. These tests resulted in low
sulfur values in the treated coal fraction. There is also more material loss, as would be
expected from the length of time at 1500°F. The remainder of theruns were made to
establish the residence time necessary at the various final temperatures. Examination of
the data shows increased sulfur removal as residence time and temperature are
increased. The lime tests show a little better removal, on the average, relative to the
no-lime tests, but this is offset by much more material recovery in the no-lime test.
Figure 16 represents the test results graphically. The pyritic and organic sulfur
content (expressed as a percentage of the .original coal sulfur) are plotted against the
effective run time (time in excess of 750°F). The effects of terminal temperature and
residence time are evident. Each temperature approaches a maximum sulfur removal as
the run time increases.
Table 28 lists the calculated sulfur emissions for the direct combustion of the
desulfurized material from each of the batch tests. The lower heat-up tests show
acceptable levels, considering both total sulfur and the sum of pyritic and organic sulfur,
for all tests except BR-76-23. This test was made at only 1300°F and, although the test
conditions were the same as BR-76-24, the treated coal was not subjected to the
separation techniques that would remove some of the sulfur (because lime was not used
and no lime-coal separation was required).
Rapid heat-up tests show acceptable emissions for pyritic and organic sulfur for
tests above 1300°F and/or over 60 minutes holding time. Reduction of total sulfur below
the emission limitation requires treatment at 1500°F and 60 minutes or longer.
Unpretreated Western Kentucky No. 9
Table 29 lists data, evaluating the effects of pretreatment, from batch reactor
tests using Western Kentucky No. 9 coal. Tests BR-76-19 and BR-76-20 were made with
unpretreated coal feed. The other two runs, BR-76-29 and BR-7 6-27, are included for
comparison because run conditions are the same. Operation with the unpretreated coal
was poor; caking resulted and some material stuck to the reactor walls. The sulfur
80
-------
oo
3.5
3.0
2.5
z>
CO
1.5
1.0
0.5
O WITH LIME
A WITHOUT LIME
D PRETREATED COAL
SULFUR CONTENT
THERMOBALANCE TESTS
ON SAME COAL
750 800 900 1000 1100 1200 1300
FINAL TEMPERATURE, °F
1400 1500 1600
A7607I45I
Figure 15. Treated material sulfur content batch reactor tests on
Western Kentucky No; 9 coal.
-------
TABLE 27. BATCH REACTOR RUN DATA FOR PRETREATED WESTERN KENTUCKY NO. 9 COAL,
N>
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, °F'min
Terminal Temperature. F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight. Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal*
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
f. No. 9 -
7
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
50
0
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
. 6
BR-76-7
0:
:1
Rapid
1500
330
Feed Residue
0.
0.
1.
1.
3.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
75
84
04
09
40
25
78
04
10
54
38
06
0. 22
0.00
0.02
0.14
0.38
51. 2
31.7
31.7
62.01
0. 14
0.00
0.01
0.09
0.24
0.02
0.14
0.16
96.4
97.1
ated W. Ky.
Feed
0. 01
0. 03
0. 52
0.46
1. 02
150
272. 52
0. 04
0. 09
1.40
I. 25
2. 78
0. 01
0. 03
0. 52
0.46
1. 02
+50
0. 13
0. 01
0. 00
0. 12
0. 26
40. 81
0. 05
0. 00
0. 00
0. 05
0. 10
--
--
0.00
0. 12
0. 12
98. 2
98. 6
BR-76-8
2:1
Rapid
1500
330
-50 Float
1.Z6 0.12
0.01 0.02
0.00 0.02,
0.03 0.14
1. 30 0. 30
n i 1
156.13 35.71
1.96 0.04
0.02 0.01
0.00 0.01
0.05 0.05
2.03 0.11
0. 02
0. 14
0. 16
97. 8
98. 3
Sink
1. 35
0. 03
0.00
0.03
1.41
161. 23
*
2. 18
0. 05
0.00
0.05
2. 28
'Calculated for 40 mesh fraction.
-------
TABLE 27.
BATCH.REACTOR RUN DATA FOR PRETREATED WESTERN KENTUCKY NO. 9 COAL
(Continued)
00
Run No.
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal, Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed Coal
+40 Mesh
Pretreated Coal
750
30
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
04
10
54
38
06
BR-76-25
0:1
Rapid
1400
60
Feed Residue
0.
0.
1.
1.
3.
04
10
54
38
06
0. 38
0. 01
0.03
0.63
1.05
75. 0
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
84
16
16
04
09
40
25
78
04
10
54
38
06
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
84
04
09
40
25
78
04
10
54
38
06
20.6
53.9
28. 13
28. 13
65. 29
0. 25
0. 01
0. 02
0.41
0.69
--
--
0.03
0.63
0.68
84. 5
87.7
BR-76-26
0:1
Rapid
1400
120
Feed Residue
0.04
0. 10
1. 54
1. 38
'. 3.06
75.0
90.84
0.04
0.09
1.40
1. 25
2.78
0.04
0. 10
1. 54
1.38
3.06
0. 24
0.01
0.04
0.42
0.71
53. 2
29.1
29.1
64.41
0.15
0.01
0.03
0. 27
0.46
--
--
0.04
0.42
0.46
89. 2
91.4
BR-76-27.
0-1
Rapid
1500
60
Feed Residue
0.04
0. 10
1. 54
1.38
3.06
75.0
90.84
0.04
0.09
1.40
1.25
2.78
0.04
0. 10
1. 54
1.38
3.06
0.47
0.00
0.02
0.43
0. 92
53.4
28.8
28.8
64.68
0. 30
0.00
0.01
0.28
0. 59
--
--
0.02
0.43
0.45
89.6
91.7
^Calculated for 40 mesh fraction.
-------
TABLE 27. BATCH REACTOR
RUN DATA FOR PRETREATED
(Continued)
WESTERN KENTUCKY NO. 9 COAL,
Run No.
Lime/Coal Feed Ratio
Heating Rate, F/min
Terminal Temperature, F
Holding .Time, min
Sulfur,- wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
. Initial
Weight Loss, %
. Coal Weight
-Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
Coal'
+40 Mesh
Pretreated Coal
750
30
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
-
04
10
54
38
06
04 .
16
04
09
40
25
78
04
10
54
38
06
Feed
0
0
0
0
1
272
0
0
1
1
2
0
0
0
0
1
.01
.03
. 52
.46
.02
150
. 52
.04
.09
.40
. 25
.78
.01
.03
. 52
.46
.02
20.6
+50
0. 13
0.03
. 0.02
0.46
0.64
57. 28
0.07
0.02
0.01
0.26
0. 36
--
--
0.02
0.46
0.48
90.3
92. 3
BR-76-28
BR-76-29
2:1 . .;,; 0:1
Rapid -Rapid
,1500 ' 1500
60 30
50 Float Sink Feed Residue
1.25 0.
0.10 0.
0.00 0.
0.39 0.
1. 74 0.
135.85 57.
1.70 0.
0. 14 0.
0.00 0.
0.53 0.
2.37 0.
. 0.
0.
0.
93
94
13 1.55
04 0.14
02 0.00
32 0.11
51 1.80
55 135.58
07 2.10
02 0.19
01 0.00
18 0.15
28 2. 44
--
--
02
32
34
.2
.6
0. 04
0. 10
1. 54
1. 38
3. 06
75
90. 8.4
0. 04
0. 09
1. 40
1. 25
2. 78
0. 04
0. 10
1. 54
1. 38
-3. 06
0. 47
0. 02
0. 01
0. 64
1.14
27. 73
65.65
0. 31
0.01
0.01
0. 42
0. 75
--
--
0.01
0. 64
0.65
84. 5
87. 7
*Calculated for 40 mesh fraction.
-------
TABLE 27.
BATCH REACTOR RUN DATA FOR PRETREATED
(Continued)
WESTERN KENTUCKY NO. 9 COAL
+40 Mesh
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
00
Ui Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
Pretreated Coal
y. No. 9 -
7
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
BR-76-30
0:1
50
0
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
.6
Rapid
1500
120
Feed Residue
0.
0.
1.
1.
3.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
75
H4
04
09
40
25
78
04
10
54
38
06
0. 22
0.00
0.03
0. 29
0. 54
52.4
30. 13
30. .1 3
63. 47
0. 14 '
0.00
0. 02
0. 18
0. 34
--
--
0.03
0. 29
0. 32
92.8
94.3
BR-76-31
0:1
- Pretreated W. Ky. No.
Rapid
1300
60
Feed Residue
0. 04
0. 10
1.54
1.38
3.06
75
90.84
0. 04
0.09
1.40
1. 25 .
2.78
0. 04
0. 10
1.54
1.38
3.06
0. 66
0. 01
0. 03 .
0.81
1.51
55.2
26.4
26.4
66. 86
0. 44
0. 01
0. 02
0.54
1.01
-- .
--
0.03
0.81
0.84
79.9
84.0
BR-76-32
0:1
- Rapid
1300
120
Feed Residue
0. 04
0. 10
1. 54
1.38
3. 06
75
90.84
0.04
0.09
1.40
1. 25
2.78
0.04
0. 10
1.54
1.38
3.06
0.46
0.01
0.02
0.50
,0.99
54.9
26.8
26.8
66.49
0. 31
0.01
0.01
0.33
0.66
--
--
0. 02
0. 50
0.52
87.8
90. 3
'Calculated for 40 mesh fraction.
-------
I
id
0
10
20
30
40
(E 50
U.
CO
60
70
80
90
100
RAW COAL
TERMINAL
HEAT-UP TEMP,-°F
PRETREATED COAL
O SLOW
O RAPID
A SLOW
A RAPID
D SLOW
m RAPID
-I300°F
-I400°F
-1500 °F
1300
1400
1500
I
60 120 ISO 240
EFFECTIVE RUN TIME, min
300
A76I22809
Figure 16. Degree of sulfur removal in batch reactor tests as a
function of effective run time.
86
-------
TABLE 28. SO2 EMISSIONS AND HEATING VALUES FOR
WESTERN KENTUCKY NO. 9 COAL TREATED MATERIAL
lb S0?/106 Btu
Coal (Dry)
Pretreated +40 Mesh
BR-76-7 Residue
BR-76-8 +50
Float
BR-76-25 Residue
BR-76-26 Residue
BR-76-27 Residue
BR-76-28 +50
Float
BR-76-29 Float
BR-76-30 Float
BR-76-31 Float
BR-76-32 Float
Btu/lb
12,454
11,809
11,565
9,233
11,789
10,898
10,908
10,693
10,741
10,679
10,716
11,086
11,159
11,080
Total
5.62
5.18
0.66
0.56
0.51
1.93
1.30
1.72
1.19
0.96
2.13
0.97
2.71
1.79
Pyritic &
Organic
4.63
4.95
0.28
0.26
0.27
1.25
0.84
0.84
0.90
0.64
1.21
0.58
1.51
0.94
Total Heating Value,
Btu/ 100 lb Coal Feed
1,245,400
1,072,730
717,146
376,799
420,985
711,530
702,584
691,623
615,244
614,576
703,505
703,628
746,091
736,709
87
-------
TABLE 29.
oo
00
COMPARISON OF BATCH REACTOR RUNS WITH PRETREATED AND UNPRETREATED
WESTERN KENTUCKY NO. 9 COAL
Feed Coal*
P retreated Coal*
* Calculated for +40 mesh fraction.
t Coal feed not pretreated.
BR-76-29
Lime/Coal Feed Ratio
Heating Rate, F/min
o
Terminal Temperature, F
Holding Time, min
Sulfur, wt 1,
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30
0:1
Rapid
1500
30
Feed
0.
0.
1.
1.
3.
100.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
90.
9.
9-
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
04
10
54
38
06
84
16
16
84
04
09
40
25
78
04
10
54
38
06
.6
0.
0.
1.
1.
3.
75
02
60
06
82
50
. 0
Residue
0
0
0
0
1
. 27
.01
.05
. 92
. 25
0:1
Rapid
1500
30
Feed
0.
0.
1.
1.
3.
75
04
10
54
38
06
.0
32. 2
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
00
02
60
06
82
50
02
60
06
82
50
57
57
43
0
0
0
0
0
0
0
0
84
. 07
. 07
. 93
. 12
. 00
.02
.40
. 54
-
-
.05
. 92
. 97
. 57
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
84
04
09
40
25
78
04
10
54
38
06
Residue
0.47
0.02
0.01
0.64
1. 14
54. 2
27.73
27. 73
65.65
0.31
0.01
0.01
0.42
0.75
-
-
0.01
0.64
0.65
84. 5
87.7
B77010079
-------
TABLE 29.
oo
VO
COMPARISON OF BATCH REACTOR RUNS WITH PRETREATED AND UNPRETREATED
WESTERN KENTUCKY NO. 9 COAL (Continued^
Feed Coal*
P retreated Coal*
BR-76-27
Lime/Coal Feed Ratio
Heating Rate. F/min
o
Terminal Temperature. F
Holding Time, min
Sulfur, wt 1.
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight. Ib
Sulfur Weight. Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30
0:1
Rapid
1500
60
Feed
0.
0.
1.
1.
3.
100.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
04
10
54
38
06
0.
0.
1.
1.
3.
02
60
06
82
50
Residue
0.
0.
0.
o._
1.
36
02
06
12
03
75.0
90.
9.
9.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
84
16
16
84
04
09
40
25
78
04
10
54
38
06
100.
0.
0.
1.
JL
3.
0.
0.
1.
1.
3.
00
02
60
06
11
50
02
60
06
82
50
20. 6
43
42
42
58
0.
0.
0.
0.
0.
0.
0..
0.
89.
. 5
.0
.0
.0
21
01
03
34
59
06
12
65
43
0:1
Rapid
1500
60
Feed
.0.
0.
1.
1.
3.
04
10
54
38
06
Residue
0.47
0.00
0.02
0.43
0. 92
75.0
90.
0.
0.
1.
1^
2.
0.
0.
1.
1.
3.
84
04
09
40
11
78
04
10
54
38
06
53.4
28.8
28.8
64.68
0. 30
0.00
0.01
0.28
0. 59
-
-
0.02
0.43
0.45
89.6
91.7
* Calculated for +40 mesh fraction.
t Coal feed not pretreated.
B77010079
-------
contents in Table 29 show that the residual organic sulfur in the unpretreated coal tests
is much higher than the others. Treated material recovery is less in the unpretreated
runs. Results of both sulfur removal and material recovery substantiate the need for
adequate coal pretreatment.
Siderite Acceptor Runs
Analyses of batch reactor runs BR-76-9 to BR-76-11 are shown in Table 30.
Sintered siderite (FeO), rather than lime, was used as an acceptor in these runs. Con-
ditions were similar to the previous pretreated Western Kentucky No. 9 coal runs, with
lime, for comparisons. Data for the comparable lime-acceptor tests are shown in
Table 31. The results with the iron acceptor are similar to the results of the lime runs in
both reduced sulfur values and materials recovery.
There was difficulty in both operation and laboratory analysis with these runs.
The heavier siderite was not amenable to good fluidization and mixing. The additional
iron is a detriment in our sulfur-by-types analysis because the pyritic sulfur analysis is
made on the iron determination. Great care must be taken so that errors are not made.
The siderite appears to be as satisfactory as the lime for an acceptor material. It has
the disadvantage of poor mixing and difficulty of analysis. One significant advantage is
that it can be regenerated with steam without carbonate formation. The siderite is
therefore a feasible candidate for the overall process, should the acceptor concept be
desirable.
Nitrogen-Hydrogen Mixtures
Four batch reactor runs were made with mixtures of nitrogen and hydrogen to
determine baseline conditions and if nitrogen could be used for the fluidizing control gas,
as was done in pretreatment runs.
The results for these runs are shown in Table 32 and graphically represented in
Figure 17. The tests used concentrations of hydrogen at 5%, 10%, 20%, and 50% with the
balance nitrogen. One previous run with 100% hydrogen is included in the table and -
graph.
Results show that the hydrogen concentration must be at least 50% to reduce
sulfur content adequately. The organic sulfur reduction is the controlling factor because
the pyritic sulfur has been nearly eliminated in all the runs, regardless of the hydrogen
concentration.
Hydrogen-Carbon Monoxide-Water Mixtures
Batch runs were attempted using mixtures of H^ and CO. Extremely fine carbon
from the reaction
2CO -» CO2 + C
plugged the porous plate in the reactor. Rapid heat-ups failed to avoid the problem, so
water, was added to the system.
90
-------
TABLE 30. BATCH REACTOR RUN DATA, WESTERN KENTUCKY NO. 9 COAL WITH SIDERITE
Feed Coal
Pretreated Coal
vO
Run No.
Side rite /Coal Feed Ratio
Heating Rate, F/min
Terminal Temperature,
Holding Time, Min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, 1,
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt In
From Feed
From Coal
°F
0. 02
0.60
1. 06
1. 82
3. 50
100. 00
0. 02
0. 60
1. 06
1.82
3. 50
0. 02
0. 60
1. 06
1. 82
3. 50
750
30
0.04
0. 10
1. 54
1. 38
3.06
on 04
9.16
9.16
0. 04
0.09
1. 40
1. 25
2. 78
0.04
0. 10
1. 54
1. 38
3. 06
20.6
Feed
0.01
0.03
0. 52
0.46
1.02
150
272. 52
0.04
0. 09
1.40
1. 25
2. 78
0.01
0.03
0. 52
0.46
1.02
BR-76-9
2:1
15
1500
230
+50 -50 Total
0.12 1.06 0.79
0.00 0.01 0.00
0.00 0.06 0.01
0.13 0.03 0.06
0.25 1.16 0.86
59. 97 148. 23 208. 20
0.07 1.57 1.64
0.00 0.01 0.00
0.00 0.09 0.02
0.08 0.04 0.12
0.15 1.71 1.78
0.00
0.00
0.00
0.13
0.13
97.1
97.7
BR-76-10
Feed
0.01
0.03
0.52
0.46
1.02
150
272.52
0.04
0.09
1.40
1.25
2.78
0.01
0.03
0.52
0.46
1.02
+50
0. 10
0.00
0.01
0. 20
0.31
61. 53
0.06
0.00
0.01
0.12
0. 19
0.00
0.00
0.01
0.20
0.21
95. 3
96.3
2:1
5
1500
30
-50 Float
0.74 0.03
0.05 0.00
0.09 0.01
0.03 0.20
0. 91 0. 24
149.59 55.48
1.11 0.02
0.07 0.00
0.13 0.01
0.04 0.11
1.35 0.14
0.00
0.00
0.01
0.20
0.21
95.7
96.6
Sink
0.74
0.03
0. 10
0.02
0.89
155.64
1. 15
0.05
0. 16
0.03
1.39
Calculated for 40 mesh.
B76091966
-------
TABLE 30.
BATCH REACTOR RUN DATA, WESTERN KENTUCKY NO. 9 COAL WITH SIDERITE
(Continued)
Feed Coal'
IO
N)
Run No.
Siderite/Coal Feed Ratio
Heating Rate, F/min
o
Terminal Temperature, F
Holding Time, Min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Py riti c
Organic
Total
Sulfur Content,
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt <5£,
From Feed
From Coal
Calculated for 40 mesh.
0. 02
0.60
1. 06
1. 82
3. 50
100.00
0. 02
0. 60
1. 06
1.82
3. 50
0. 02
0. 60
1. 06
1^82
3. 50
Pretreated Coal
750
30
0.04
0. 10
1. 54
1. 38
3. 06
90. 84
9. 16
9.16
0. 04
0.09
1. 40
1. 25
2. 78
0. 04
0. 10
1. 54
1. 38
3. 06
20. 6
BR-76-11
Feed
0. 01
0. 03
0. 52
0.46
1.02
150
272. 52
0. 04
0. 09
1. 40
1. 25
2. 78
0.01
0.03
0. 52
0.46
1.02
+50
0. 12
0. 01
0.02
0. 22
0. 37
55.17
0. 07
0. 01
0.01
0. 12
0. 21
0.00
0. 00
0.02
0. 22
0. 24
95. 3
96.3
2:1
5
1500
30
-50 Float
0.53 0.06
0.03 0.01
0.28 0.01
0.02 0.17
0. 86 0. 25
mr
152.76 53.11
0.81 0.03
0.05 0.01
0.43 0.01
0.03 0.09
1.32 0.14
0.00
0.00
0. 01
0. 17
0. 18
96.4
97. 1
B76091966
Sink
0.71
0.03
0. 12
0.03
0.89
154.82
1. 10
0. 05
0. 19
0.05
1.39
-------
TABLE 31. BATCH REACTOR RUN DATA FOR WESTERN KENTUCKY NO. 9 GOAL,
OJ
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, F/min
Terminal Temperature, F
Holding' Time, min
Sulfur, wt"%
Sulfide
Sulfate .
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyrttic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal'
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
/. No. 9 -
7
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
BR-76-3
0:1
50
0
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
.6
5
1500
30
Feed Residue
0.04
0. 10
1. 54
1.38
3.06
75.0
90. 84
0.04
0.09
1.40
1.25
2.78
0.04
0. 10
1. 54
1.38
3.06
0. 12
0.00
0.02
0. 37
0.51
51.7
31.1
31.1
62.62
.
0.08
0.00
0.01
0. 23
0. 32
0.02
0. 37
0. 39
91.4
93.1
retreated W. Ky. No. 9
Feed +50
0. 01
0. 03
0. 52
0. 46
1. 02
150
272. 52
0. 04
0. 09
1. 40
1. 25
2. 78
0.01
0. 03
0. 52
0.46
1.02
0. 22
0. 01
0. 02
0. 17
0. 42
53. 17
0. 12
0. 01
0. 01
0. 09
0. 23
0. 02
0. 17
0. 19
96. 4
97. 1
BR-76-4
2:1
5
1500
30
-50 Float
1.29 0.
0.05 0.
0.00 0.
0. 04 0.
1. 38 0.
168. 29 49.
2. 17 0.
0.08 0.
0.00 0.
0.07 0.
2. 32 0.
0.
0.
0.
93
95
10
00
01
32
43
68
05
00
01
16
22
01
32
33
. 9
. 1
Sink
1. 30
0.03
0.00
0.08
1.41
171. 78
2. 23
0. 05
0. 00
0. 14
2. 42
^Calculated for 40 mesh fraction.
-------
TABLE 31. BATCH REACTOR RUN DATA FOR WESTERN KENTUCKY NO. 9 COAL (Continued)
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
VO Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
Coal*
+40 Mesh
Pretreated Coal
750
30
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
BR-76-5
0
:1
20
1500
240
Feed Residue Feed
0.
0.
1.
1.
3.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
75
84
04
09
40
25
78
04
10
54
38
06
20. 6
0. 26
0. 01
0.02
0. 27
0. 56
41. 3
44. 93
44. 93
50.02
0. 13
0. 01
0. 01
0. 14
0. 29
--
--
0.02
0. 27
0. 29
94.6 -
95. 7
0.01
0.03
0. 52
0.46
1. 02
150
272. 52
0. 04
0.09
1. 40
1. 25
2. 78
0.01
0.03
0. 52
0.46
1.02
+50
0. 13
0.00
0.00
0.09
0. 22
53. 96
0.07
0.00
0.00
0. 05
0. 12
--
--
0.00
0.09
0.09
98.2
98.6
BR-76-6
2:1
20
1500
240
-50 Float
l.OZ 0.06
0.01 0.01
0.00 0.03
0.02 0.19
1.05 0.29
. 162.97 48.01
1.66 0.03
0.02 0.00
0.00 0.01
0.03 0.09
1.71 0.13
--
--
0.03
0. 19
0. 22
96.4
97. 1
Sink
0. 95
0.03
0.00
0.02
1.00
168. 92
1.60
0.05
0.00
0.03
1.68
*Calculated for 40 mesh fraction.
-------
TABLE 32.
Ul
PRETREATED WESTERN KENTUCKY NO. 9 COAL BATCH REACTOR RUNS
WITH N2-H2 GAS MIXTURES
Run No.
Lime/Coal Feed Ratio
Heating Rate, F/min
Terminal Temperature,
Holding Time, min
H2/N2 Gas Ratio
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
F
Coal*
Pretreated Coal*
750
30
BR-76-3
0:1
5
1500
30
100:0
Feed
0.
0.
1.
1.
3.
100.
.100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
90.
9.
9.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
84
16
16
84
04
09
40
25
78
04
10
54
38
06
0.
0.
1.
1.
3.
75
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
. 0
84
04
09
40
25
78
04
10
54
38
06
20. 6
Residue
0. 12
0:00
0.02
0. 37
0.51
51.7
31. 1
31.-1
62.62
0.08
0.00
0.01
0. 23
0. 32
0.02
0. 37
0. 39
91.4
93.1
BR-76-12
0
5
1500
30
5:95
Feed
: 0.04
0.10
1. 54
1. 38
3.06
75. 0
90.84
0.04
0.09
1.40
1. 25
2. 78
0.04
0. 10
1. 54
1.38
3.06
Residue
0.80
0.00
0.04
1. 37
2. 21
49. 2
34.4
34.4
59.59
0.48
0.00
0.02
0. 82
1. 32
0.04
1.37
1.41
69.8
76. 0
BR-76-13
0
5
' 1500
30
10:90
Feed
0.04
0. 10
1.54
1.38
3.06
75.0
90.84
0.04
0.09
1.40
1.25
2.78
0.04
0.10
1.54
1.38
3.06
Residue
0.69
0..01
0.03
1. 17
1. 90
54.7
27.1
27.1
66.22
0.46
0.01
0.02
0.77
1.26
0.03
1.17
1. 20
71.6
77.4
^Calculated for 4-40 mesh.
B76092056
-------
TABLE 32.
PRETREATED WESTERN KENTUCKY NO. 9 COAL, BATCH REACTOR RUNS
WITH N2-H2 GAS MIXTURES (Continued)
vo
Run No.
Feed
Coal*
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
H2/N2 Gas Ratio
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Pretreated Coal*
750
30
BR-76-14
0
5
1500
30
20:80
Feed
0.
0.
1.
1.
3.
100.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
02
60
06
82
50
00
00
02
60
06
82
50
02
60
06
82
50
0.
0.
1.
1.
3.
90.
9.
9.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
04
10
54
38
06
84
16
16
84
04
09
40
25
78
04
10
54
38
06
. 6
0.
0.
1.
1.
3.
75
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
34
06
.0
84
04
09
40
25
78
04
10
54
38
06
Residue
0.
0.
0.
0.
1.
55
26
26
66.
0.
0.
0.
0.
0.
0.
0.
1.
75
80
41
01
03
99
44
.3
.3
. 3
95
27
01
02
66
96
03
99
02
. 5
.6
BR-76-15
0
5
1500
30
50:50
Feed
0.
0.
1.
1.
3.
75
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
34
06
.0
84
04
09
40
25
78
04
10
54
38
06
Residue
0. 27
0.02
0.04
0.49
0.82
53. 2
29.0
29.0
64.49
0.17
0.01
0.03
0.32
0.53
0.04
0.49
0. 53
87.4
90.0
*Calculated for +40 mesh.
B76092056
-------
OA-RAW COAL-
10
20
-------
Two runs, BR-76-45 and BR-76-46, were accomplished using the I^-
mixture. Concentrations of CO over 37.5% precipitate enough carbon to plug the
diffusion plate. Data from the two runs are shown in Table 33. The test with a low CO
concentration yielded results similar to a previous batch reactor run with hydrogen at the
same conditions. The second run gave higher sulfur values, but in both runs the treated
material yields an acceptable SO2 emission when burned.
1% H2S in Hydrogen
Analysis of the conceptual flow sheet for the process indicated that the off-gas
from the hydrodesulfurization could contain significant H^S concentrations. Conse-
quently, batch reactor tests were made with H^S in the hydrogen feed.
Table 34 shows the comparison of results from tests using pure hydrogen and those
using 9800 ppm (0.98%) I^S in hydrogen. The two tests with r^S-bearing gas, I^S-l and
H2S-2, were made at conditions similar to two previous batch reactor runs that did not
contain H2S in the feed gas. The first pair of runs in the table, H2S-1 and BR-76-27,
were both heated rapidly to 1500°F and then held for 60 minutes. Sulfide-type sulfur is
much higher for H^S-l, and organic sulfur has not been reduced as much as in BR-76-27.
The second pair of runs were heated rapidly to 1400°F and held for 60 minutes. Sulfur
values are higher for H2S-2 than for BR-76-25 at the same conditions.
These tests indicate that a high back pressure of hydrogen sulfide inhibits the de-
sulfurization of the coal. The effect is greater at lower temperature.
ILLINOIS NO. 6 COAL RUNS
Results and run conditions for a series of batch reactor tests made with 10+40
mesh pretreated Illinois No. 6 coal are shown in Table 35. Sulfur removal is increased as
the final temperature or holding time is increased. Material recovery from these tests is
excellent.
A second series of tests, shown in Table 36, was made with the same conditions,
but the pretreated Illinois No. 6 coal was not screened before the tests. This was done to
see if the coal particle size was a factor in the sulfur removal step. The sample for
BR-76-38 was accidentally discarded before sulfur-by-type was determined, but total
sulfur shows it to follow the trends associated with temperature and holding time. Com-
parison between these tests and those of Table 35 show essentially no difference in sulfur
removal and slight differences in material recovery. These results indicate that sulfur
removal from the 40 mesh material is no more difficult than from the +40 mesh.
The last four runs, shown in Table 37, were made with screened, pretreated Illinois
No. 6 coal mixed with lime. Run conditions again are the same as in the two previous
sets. There is slightly better sulfur removal in these tests than the previous two,
probably due to the separation step. The lower sulfur is offset by less material recovery
and some carbon loss to the 50 mesh (lime) material.
Calculated SO? emissions and heating values for the treated material from the
12 runs are shown in Table 38. The emissions for all are below the 1.2 Ib SO^/million Btu
limit for total sulfur. The total heating value is higher for the runs without lime.
98
-------
TABLE 33. BATCH REACTOR RUN DATA
VO
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Sulfur, wt %
Sulfide 0.02
Sulfate 0.60
Pyritic 1.06
Organic 1.82
Total 3.50
Weight, g
Initial 100.00
Treated
Weight Loss, 7.
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide 0.02
Sulfate 0.60
Pyritic 1.06
Organic 1.82
Total 3.50
Sulfur Content, %
Sulfide 0.02
Sulfate 0.60
Pyritic 1.06
Organic 1.82
Total 3.50
Sulfur Removal, wt %
From Feed
From Coal
* Gas composition: 25% H,0, 62.5% H-, 12.5% CO.
** Gas composition: 25% H20, 37.5% HZ> 37.5% CO.
Feed Coal Pretreated Coal, +40 mesh
W. Ky. No. 9 W. Ky. No. 9
750
30
0.04
0.10
1.54
1.38
3.06
90.84
9.16
9.16
0.04
0.09
1.40
1.25
2.78
0.04
0.10
1.54
1.38
3.06
20.6
Run No.
BR-76-7
Pretreated W. Ky. No. 9
Feed
0.04
0.10
1.54
1.38
3.06
75
~
90.84
0.04
0.09
1.40
1.25
2.78
0.04
0.10
1.54
1.38
3.06
Rapid
1500
330
Residue
0.22
0.00
0.02
0.14
0.38
51.2
31.7
31.7
62.01.
0.14
0.00
0.01
0.09
0.24
0.02
0.14
0.16
96.4
97.1
BR-76-45*
Pretreated W. Ky. No. 9
Feed
0.04
0. 10
1.54
1.38
3.06
50
90.84
0.04
0.09
1.40
1.25
2.78
0.04
0.10
1.54
1.38
- 3.06
Rapid
1500
330
Residue
0.04
0.00
0.05
0.07
0.16
32
36.0
36.0
58.1
0.02
0.00
0.03
0.04
0.09
0.05
0.07
0.12
97.5
98.0
BR-76-46**
Pretreated W. Ky. No. 9
Feed
0.04
0.10
1.54
1.38
3.06
50
90.84
0.04
0.09
1.40
1.25
2.78
0.04
0.10
1.54
1.25
2.93
Rapid
1500
330
Residue
0.09
0.00
0.04
0.19
0.32
36.6
26.8
26.8
66.5
0.06
0.00
0.03
0.13
0.22
0.04
0.19
0.23
94.2
95.4
B77051092
-------
TABLE 34. COMPARISON OF SULFUR VALUES FOR H2 AND H2-H2S RUNS
Run No. H7S-1 BR-76-27 H2S-2 BR-76-25
Heating Rate, °F/min Rapid Rapid Rapid Rapid
Terminal Temperature, °F 1500 1500 1400 1400
Holding Time, min 60 60 60 60
Sulfur, wt %
Sulfide 0.83 0.47 0.65 0.38
Sulfate 0. 00 0.00 0. 03 0.01
Pyritic 0.03 0.02 0. 06 0. 03
Organic 0.75 0.43 1.48 0.63
Total 1.61 0.92 2.22 1.05
100
-------
TABLE 35. BATCH REACTOR TESTS- PRETREATED ILLINOIS NO. 6 COAL (-10+40 MESH)
Feed Coal*
Pretreated Coal*
Lime/Coal Feed Ratio
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt <7<,
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g .
Initial
Treated .
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
P.yritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30 "
0:1
5
1400
30
Feed
0.
0.
0.
1.
2.
100.
01
13
84
50
48
00
0.
0.
0.
1.
2.
01
04
65
52
22
0.
0.
0.
1.
2.
01
04
65,
52
22
Residue
0.
0.
0.
0.
0.
04
01
03
56
64
75.0
90
. 4
9.6
9.6
100.
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
00
01
13,
84
50
48
01
13
84
50
48
90
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
18
.4
01
04
59
37
01
01
04
65
52
22
. 9
90
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
.4
01
04
59
37
01
01
04
65
52
22
54
27
27
65
0.
0.
0.
0.
0.
-
0.
0.
0.
80
84
. 2
.7
.7
.4
03
01
02
37
43
03
56
59
.6
.3
0:1
5
1500
30
Feed
0.
0.
0.
1.
2.
01
04
65
52
22
Residue
0.05
0.05
0.03
0. 47
0.60
75.0
90
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
.4
01
04
59
37
01
01
04 '
65
52
22
52. 2
30.4
30.4
62.9
0.03
0.03
0.02
0. 30
0. 38
0.03
0.47
0. 50
84.1
87.1
*Calculated for +40 mesh fraction.
B77020379
-------
TABLE 35.
BATCH REACTOR TESTS - PRETREATED ILLINOIS NO. 6 COAL (-10 +40 MESH)
(Continued)
Feed Coal*
Pretreated Coal*
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt <7o
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, lt>
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30
0:1
20
1500
120
Feed
0.
0.
0.
1.
2.
100.
100.
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
01
13
84
50
48
00
00
01
13
84
50
48
01
13
84
50
48
0.
0.
Q.
1.
2.
90
9
9
90
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
01
04
65
52
22
. 4
.6
.6
.4
01
04
59
37
01
01
04
65
52
22
0.
0.
0.
1.
2.
75
90
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
01
04
65
52
22
. 0
.4
01
04
59
37
01
01
04
65.
52
22
Residue
0.
0.
0.
0.
0.
61
17
17
74
0.
0.
0.
0.
0.
0.
0.
0.
03
00
03
44
50
.8
.6
.6
. 5
02
00
02
33
37
03
44
47
0:1
Rapid
1500
240
Feed
0.
0.
0.
1.
2.
75
90
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
01
04
65
52
22
.0
.4
01
04
59
37
01
01
04
65
52
22
82.6
18
.9
85. 9
Residue
0.03
0.00
0.04
0.35
0.42
53.6
28. 5
28.5
64.6
0.02
0.00
0.03
0.23
0.28
0.04
0.35
0. 39
87.1
89.5
*Calculated for +40 mesh fraction.
B77020379
-------
TABLE 36. BATCH REACTOR TESTS- PRETREATED ILLINOIS NO. 6 COAL (UNSCREENED)
Feed Coal
Pretreated Coal
BR-76-38
O
U>
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
' Total
Weight, g
Initial
Treated
Weight Loss. %
Total Weight
Coal Weight
Reduced Data
Weight. Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
0.01
0. 13
0. 83
1.48
2.45
100.00
100. 00
0. 01
0. 13
0. 83
1.48
2.45
0.01
0. 13
0.83
1.48
2.45
0. 01
0. 04
0.64
1. 50
2. 19
90. 4
90.4
0. 01
0.04
0. 58
1. 34
1.97
0.01
0.04
0.64
1. 50
2. 19
19.6
Feed
0.01
0. 04,
0.64
1. 50
2.19
75.0
90.4
0.01
0.04
0. 58
1. 34
1.97
0.01
0.04
0.64
1. 50
2.19
0:1
5
1400
30
Residue
0.06
0.00
'0.04
o.'ss .
0.65
53.4
28. 8
28. 8
64.4
0.04
0.00
0.03
0.35
0.42
0.04
0. 55
0. 59
80. 7
81. 5
Feed
0.01
0.04
0.64
1. 50
2.19
75.0
90.4
0.01
0.04
0. 58
1. 34
1.97
0.01
0.04
0.64
1. 50
2.19
0:1
5
1500
30
Residue
0.64
60, 7
19.1
19.1
73. 1
0.47
B77020380
-------
TABLE 36. BATCH REACTOR TESTS -
PRETREATED ILLINOIS NO. 6 COAL (UNSCREENED)
(Continued)
Feed Coal
Pretreated Coal
O
.p-
Lime/Coal Feed Ratio
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight. Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
' Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
0.01
0. 13
0. 83
1.48
2. 45
100.00
100.00
0. 01
0. 13
0. 83
1.48
2.45
Q.0\
0. 13
0. 83
1 . 48
2.45
0. 01
0. 04
0.64
1. 50
2.19
90. 4
90.4
0. 01
0.04
0. 58
1. 34
1. 97
0.01
0.04
0.64
1. 50
2.19
19.6
Feed
0.01
0.04
0.64
1. 50
2.19
75.0
90.4
0.01
0.04
0. 58
1. 34
1.97
0.01
0.04
0.64
1.50
2.19
0:1
20
1500
120
Residue
0.05
0.01
0.03
0.41
0. 50
53.9
28.1
28.1
65.0
0.03
0.01
0.02
0.27
0.33
0.03
0.41
0. 44
85.3
88.2
Feed
0.01
0.04
0.64
1.50
2.19
75.0
90.4
0.01
0.04
0.58
1. 34
1.97
0.01
0.04
0.64
1. 50
2.19
0:1
Rapid
1500
240
Residue
0.05
0.01
0.03
0.35
0.44
53.0
29.3
29.3
63.9
0.03
0.01
0.02
0.22
0.28
0.03
0.35
0.38
87.8
90.2
B77020380
-------
TABLE 37. BATCH REACTOR TESTS - PRETREATED ILLINOIS NO. 6 COAL (-KH-40 MESH + LIME)
Feed Coal* Pretreated Coal*
Lime/Coal Feed Ratio
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate .
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss,' %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, % .
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30
Feed
0.
0.
0.
1.
2.
100.
100.
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
01
13
84
50
48
00
00
01
13
84
50
48
01
13
84
50
48
0.
0.
0.
1.
2.
90
9
9
90
0.
0.
0.
1.
2.
0.
0.
0.
1.
Z.
18
01
04
65
52
22
.4
.6
.6
.4
01
04
59
37
01
01
04
65
52
22
. 9
0.
0.
0.
0.
0.
150
00
01
22
51
74
.0
2:1
5
1400
30
+50
0. 10
0.00
0.03
0.43
0. 56
-50
1.27 '
0.07
0.01
0.10
1.45
Feed
0.00
0.01
0.22
0. 51
0.74
150.0
2:1
5
1500
30
+50
0.12
0.00
0.02
0.27
0.41
111. 2 '
271.
0.
0.
0.
1.
2.
0.
0.
0.
0.
0.
20
01
04
59
37
01
00
01
22
51
74
71. 20
0.07
0.00
0.02
0. 31
0.40
0.03
0.43
0.46
83.6
86.7
25.9
77.6
129. 75
1.65
0.09
0.01
0. 13
1.88
271.20
0.01
0.04
0. 59
1.37
2.01
0.00
0.01
0.22
0.51
0.74
55. 14
0.06
0.00
0.01
0. 15
0.22
0.02
0.27
0. 29
92.0
93.5
-50
1.10
0.02
0.01
0.10
1.23
103.5
31.0
93.0
131.99
1.45
0.03
0.01
0.13
L 62
'Calculated for +40 mesh fraction.
B77020381
-------
TABLE 37.
BATCH REACTOR TESTS - PRETREATED ILLINOIS NO. 6 COAL (-KM-40 MESH + LIME)
(Continued)
Feed Coal* Pretreated Coal*
Lime/Coal Feed Ratio
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
750
30
2:1
20
1500
120
Feed
0.
0.
0.
1.
2.
100.
100.
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
01
13
84
50
48
00
00
01
13
84
50
48
01
13
84
50.
48
0.01
0.04
0.65
1. 52
2. 22
90.4
9.6
9.6
90.4
0.01
0.04
0. 59
1. 37
2.01
0.01
. 0.04
0.65
1. 52
2. 22
18. 9
0.
0.
0.
0.
0.
150
271.
0.
0.
0.
1.
2.
0.
0.
0.
0.
0.
00
01
22
51
74
.0
20
01
04
59
37
01
00
01
22
51
74
+ 50 -50
0.
0.
0.
0.
0.
64.
0.
0.
0.
0.
0.
0.
0.
0.
91
93
13 1.
01 0.
05 0.
21 0.
40 1.
- 110.3-
- 26. 5-
- 79.4-
51 134.
08 1.
01 0.
03 0.
14 0.
26 1.
05
21
26
. 5
. 1
14
05
02
12
33
81
54
07
03
16
80
Feed
0.00
0.01
0. 22
0.51
0.74
150.0
271.20
0.01
0.04
0. 59
1.37
2.01
0.00
0.01
0.22
0. 51
0.74
2:1
Rapid
1500
240
+50 -50
0.14 1.
0.01 0.
0.02 0.
0.14 0.
0.31 1.
108.1-
27.9-
83.8-
58.42 137.
0.08 1.
0.01 0.
0.01 0.
0.08 0.
0.18 1.
0.02
0.14
0.16
95.5
96.3
11
06
01
25
43
11
52
08
01
34
95
*Calculated for +40 mesh fraction.
B77020381
-------
TABLE 38. SO2 EMISSIONS AND HEATING VALUES FOR
ILLINOIS NO. 6 COAL TREATED MATERIAL
Ib SOj/lO6 Btu
Run No.
Coal (Dry)
Pretreated (10+40 mesh)
Pretreated Coal
-10+40 Mesh Feed
BR-76-33
BR-76-34
BR-76-35
BR-76-36
Unscreened Feed
BR-76-37
BR-76-38
BR-76-39
BR-76-40
10+40 Mesh Feed + Lime
BR-76-41
BR-76-42
BR-76-43
BR-76-44
Btu/lb
13,022
12,915
13,069
12,999
12,793
12,872
12,902
13,177
12,976
12,918
12,903
1 2, 283
11,918
11,528
11,297
Pyritic and
Total Organic
3.76
3.44
3.35
0. 98
0.94
0.78
0.65
0. 99
0.99
0.77
0.68
0. 91
0.69
0.70
0.55
3.55
3. 36
3. 27
0.91
0.78
0.73
0.60
0.89
--
0.68
0.43
0.75
0.49
0.45
0. 28
Total Heating Value,
Btu/ 100 Ib coal feed
1,302,200
1,167,516
1,181,437
850,135
804,680
958,964
833,469
848,599
948, 546
839,670
824,502
874,550
657,159
743,671
659,971
107
-------
BENCH-SCALE TEST WORK - CONCLUSIONS
The data obtained from the batch reactor confirmed the results of the thermobalance. Conclusions from
this work included the following:
Satisfactory desulfurization of two Eastern U. S. coals was achieved.
Terminal temperature of 1500 °F and total reaction times of greater than 60 minutes are desirable.
Rapid heat-up to terminal temperature, as in afluidized-bed reactor, is satisfactory for sulfur removal.
The use of the acceptor is not imperative, based on these tests.
For satisfactory hydrodesulfurization, the coals should be pretreated.
Hydrogen content of 50% or greater in the reacting gas is desirable; carbon monoxide is apparently
equivalent to hydrogen in this regard.
« Hydrogen su(fide in the reacting gas tends to inhibit the hydrodesulfurization.
108
-------
10-INCH-DIAMETER CONTINUOUS FLUIDIZED-BED
TEST WORK - HYDRODESULFURIZATION
RESULTS
The 10-inch fluidized-bed unit, used for continuous pretreatment tests, was
utilized for hydrodesulfurization tests with Illinois No. 6 coal. Significant experimental
difficulties precluded extensive data acquisition within the constraints of the program.
Data and conditions for two initial runs are shown in Table 39. Predefined bed
temperatures and residence time were based on results from the batch reactor tests.
The results for the run at 1450°F are suspect, because of operating problems the unit
had not previously been run at these high temperatures. A plug developed in the
discharge line that would have caused some mixing of startup material and material from
the steady-state period.
The second test, at 1300°F, shows the expected reduction of pyritic sulfur, but
because the organic sulfur is not appreciably attacked, the total is high.
An inspection of the unit after these runs revealed that many of the heaters had
burned out. These heaters must have failed during the high-temperature test and could
have caused most of the operating problems. They were replaced and the unit prepared
for additional runs.
A second supply of Illinois No. 6 coal was obtained; this coal was much higher in
sulfur than the first sample.
A baseline run, using nitrogen as the fluidizing gas, was made at the same
conditions, 1500°F and 2 hours residence time, specified for the first two hydrogen runs.
Sulfur species of the pretreated coal and the nitrogen-treated coal are listed in Table 40.
The data were not reduced because comparison of sulfur values, by type, was of interest
for the test. The overall reduction of sulfur content was minimal, and organic sulfur in
the treated coal is nearly the same as in the feedstock. Although the majority of the
pyritic and sulfate types of sulfur have been reduced to sulfide, the total sulfur quantity
of pyritic, sulfate, and sulfide types remains nearly constant. Treatment with nitrogen
therefore does not remove sulfur significantly.
Table 41 lists the results of the three tests made in the 10-inch unit with hydro-
gen. The first two runs were made at 1500°F, and the last one at 1400°F. Residence
time for all runs was 2 hours. Sulfur has not been adequately reduced in any of the tests.
All tests show that sulfide-type sulfur has been produced, but not subsequently reduced.
Neither has the organic sulfur been sufficiently removed. Material recovery is 68% to
70% of the original raw coal feed, with the fines from the cyclone calculated as product.
Some explanation of the reason for the poor sulfur removal may be seen in the gas
analyses of Table 42. These show an average sulfur content in the gas near 4000 ppm or
109
-------
TABLE 39. 10-INCH UNIT DATA - PRETREATED ILLINOIS NO. 6 COAL
Run No.
o
Temperature, F
Residence Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight Loss
Reduced Data
Weight. Ib
Sulfur Weight, Ib
Feed Coal
0. 01
0. 13
0. 83
1.43
2. 45
100.0
Pretreated Coal
750
30
0. 01
0.04
0. 64
1. 50
2. 19
9.6
90.4
PDS-76-1
1450
90
0. 89
0.00
0.06
1. 1.2
2. 07
54. 2
PDS-76-.2
1300 '
90
0.45
0.07
0.08
0. 98
1.58
57. 2
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
0.
0.
0.
1.
2.
0.
0.
0.
1.
2.
01
13
83
48
45
01
13
83
43
45
0
0
0
1
1
0
0
0
1
.2
. 1
.01
. 04
. 58
. 34
. 97
.01
. 04
.64
. 50
.19
9.6
0.
0.
0.
0.
1.
0.
1.
1.
67
73
48
00
03
61
12
06
12
18
. 5
. 9
0. 26
0.04
0.05
0. 56
o. 91
0.08
0. 98
1.06
69.0
75.1
B77020382
-------
TABLE 40. SULFUR SPECIES IN NITROGEN RUN
Sulfur, wt % Pretreated.Coal NDS-1
Sulfide 0.02 0. 85
Sulfate 0.15 0.03
Pyritic 0.98 0.15
Organic 2.24 2.05
Total 3.39 3.08
111
-------
TABLE 41. 10-INCH UNIT RUNS WITH PRETREATED ILLINOIS NO. 6 COAL
Raw Coal
Temperature
Residence Time, min
Sulfur, wt %
Sulfide 0.01
Sulfate 0.02
Pyritic 1. 87
Organic 2. 59
Total 4.49
Weight, Ib
Initial 100.00
Treated
Weight Loss, %
P Raw Coal
110 Pretreated Coal
Reduced Data
Weight, Ib 100.00
Sulfur Weight, Ib
Sulfide 0.01
Sulfate 0.02
Pyritic 1.87
Organic 2. 59
Total 4.49
Sulfur Content, %
Sulfide 0.01
Sulfate 0.02
Pyritic 1. 87
Organic 2. 59
Total 4.49
Sulfur Removal, wt %
From Pretreated Coal
From Raw Coal
Pretreated Coal
750
30
0.02
0.15
0.98
2.24
3.39
90. 1
9.9
90.9
0.02
0. 14
0.89
2.04
3.09
0.02
0.15
0.98
2.24
3.39
24. 5
PDS-77-1
1500
120
0.72
0.05
0.28
1.35
2.40
90. 1
69.6
30.4
22.7
69.6
0. 50
0.03
0.19
0.94
1.66
0.28
1.35
1.63
63.4
74. 8
PDS-77-2
1500
120
1.24
0.01
0. 11
0.93
2.29
90. 1
67.9
32.1
24.6
67.9
0.84
0.01
0.07
0.63
1.55
0.11
0.93
1.04
77. 3
84.4
PDS-77-3
1400
120
1.13
0.01
0.05
0.86
2.05
90. 1
70.2
29. 8
22. 1
70.2
0.79
0.01
0.04
0.60
1.44
0.05
0.86
0.91
79.2
85.7
-------
TABLE 42. GAS ANALYSIS
Mass Spectrograph Analysis
PDS-77-1 PDS-77-2 PDS-77-3
Off-Gas Feed Gas Off-Gas Feed Gas Off-Gas
CO -- 2.14 4.70 0.12 4.76
CO2 -- 0.04 0.40 0.03 4.63
H2 -- 97.14 92.01 99.85 91.22
Argon -- 0.09 0.11 -- 0.32
Methane 2.32 0.59 2.68 -- 3.17
Ethane 0.02 -- 0.04 -- 0.07
Others C3+ -- -- 0.06
Sulfur Analysis
ppm as PDS-77-1 PDS-77-2 PDS-77-3
H2S 3167 5533 4347
CS2 194
Thiophene 543
113
-------
more in each case. As was proved concurrently in the batch reactor tests, sulfur removal
is reduced when the back pressure of H^S is significant.
Another major factor may be the amount of hydrogen used. In the batch reactor
tests that showed good sulfur reduction, hydrogen usage was 240 SCF/lb of coal. How-
ever, in the 10-inch unit, with the hydrogen rate specified by mechanical and fluidization
characteristics, the relative hydrogen usage was only 78 SCF/lb of coal.
The two possible causes of poorer removal lower H^/coal ratio and higher H^S
back pressure are interrelated. Discharge of the same amount of H,S into less
hydrogen will increase its H2S back pressure. Note that with increased scale-up, the
relative hydrogen/coal ratio falls still further: The hydrogen rate is determined by the
bed cross-sectional area, but the coal rate is determined by the bed volume.
Earlier in the program, the decision had been made tq eliminate the acceptor from
the process. Thermobalance and batch reactor tests had indicated that the acceptor was
unnecessary and that significant process simplification could be realized by not using the
acceptor. However, the scale-up problem, discussed above, now indicates that the
acceptor may be required in the process.
Sulfur balances for the runs are shown in Table 43. These results show good
detection of sulfur by the on-line chromatograph. Much better detection of H^S is
experienced than when grab gas samples were taken to be analyzed later. Differences in
the sulfur balances (+2% to -10%) are reasonable, considering the difficulty of sampling
and-analysis of reduced sulfur compounds, and the physical characteristics of the system.
CONTINUOUS RUNS - CONCLUSION
The data from the ]0-inch-diameter, continuous-feed reactor are insufficient to refute or to support the
conclusion from the laboratory- and bench-scale test work. One fact, however, is apparent the sulfur-getter
concept is required in the system. The high back-pressure O///2-S in larger scale equipment inhibits the
desulfurization of the coal.
114
-------
TABLE 43. SULFUR BALANCE FOR PDS RUNS
Run No.
Sulfur In, Ib
Coal Feed (12. 37 Ib/hr).
Total In
0.42
0.42
PDS-77-2
0.42
0.42
PDS-77-3
0.42
0.42
Sulfur Out.lb
Product
Gases
Total Out
0.23
P_J_1
0.40
0.21
0.22
0.43
0.20
0. 18
0.38
115
-------
NITROGEN EMISSIONS FOR TREATED COALS
Coal combustion tends to convert the nitrogen content in the coal to NOX.
Additional NO is formed from atmospheric nitrogen at combustion temperatures. The
present Federal Standard is 0.7 Ib of NOX total, from both sources, per million Btu.
Reductions of the nitrogen content of the fuel would also reduce the NOX emissions
during combustion. Some of the data from batch reactor runs were examined to
determine if significant nitrogen removal had been accomplished. Table 44 and Figure 18
present the results. The nitrogen content of the product fuel is about one-half of the
content of the raw coal, or, considering the treated material recovery, approximately
three-quarters of the nitrogen has been removed from the raw coal. The nitrogen
emissions are shown in Table 44 for the tests on Western Kentucky No. 9 coal. The
operating conditions for these runs are given in Table 45. On a 1 million Btu basis, the
amount of nitrogen has been reduced from 1.23 Ib to about 0.50 to 0.60 Ib. Figure 18
shows the percent of nitrogen remaining per million Btu and the effect of the terminal
temperature.
116
-------
TABLE 44. NITROGEN EMISSIONS FOR BATCH REACTOR TESTS
WESTERN KENTUCKY NO. 9 COAL,
Coal (Dry)
Pretreated +40 Mesh
BR-76-1, Residue
BR-76-2, +50 Mesh
Float
BR-76-3, Residue
BR-76-4, +50 Mesh
Float
BR-76-5, Residue
BR-76-6, +50 Mesh
Float
BR-76-7, Residue
BR-76-8, +50 Mesh
Float
% N,
1. 53
1.48
1. 13
0. 95
0. 93
0.78
0.61
0. 74
0. 65
0. 59
0.61
0.73
0. 56
0.62
Btu/lb
12,454
11,809
12,119
12,107
12,684
11,967
11,035
12, 134
11,651
11,463
12,029
11,565
10, 530
11,789
N2/106 Btu
1.23
1.25
0. 93
0.78
0.73
0.65
0.55
0.61
0. 56
0. 51
0.51
0.63
0. 53
0.53
-------
100
h-
^-
90
80
70
o 60
50
40
CD
S 30
20
CM
z
RAW COAL
750°
PRETREATMENT
1400° 1500°
TEMPERATURE, °F
A7609I9IO
Figure 18. Percent of nitrogen remaining after treatment, for
batch reactor tests with Western Kentucky No. 9 coal.
118
-------
TABLE 45. BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN KENTUCKY
NO. 9 COAL
Run No.
Lime /Coal Feed Ratio
Coal
Heating Rate, F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal*
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
y. No. 9 -
7
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
50
0
04
10
54
38
06
84
16
16
04
09
40
25
78
04
!°
54
38
06
.6
BR-76-1
0:
1
5
1400
30
Feed Residue
0
0
1
1
3
90
0
0
1
1
2
. 0
0
1
1
3
.04
. 10
. 54
. 38
.06
150
.84
.04
.09
.40
. 25
.78
. 04
. 10
. 54
. 38
.06
0.42
0.00
0.02
0.81
1. 25
109.8
Z6. 8
26.8
66.49
0. 30
0.00
0.01
0. 54
0. 85
0.02
0. 81
0.83
80. 2
84. 3
treated W. Ky. No. 9-
Feed +50
0.01
0.03
0. 52
0.46
1.02
150
272. 52
0.04
0.09
1.40
1. 25
2. 78
0.01
0.03
0. 52
0.46
1.02
0. 11
0.01
0.02
0. 30
0.44
61. 39
'0.07
0.01
0.01
0. 18
0. 27
0.02
0. 30
0. 32
93. 2
94.6
BR-76-2
2:1
5
1400
30
-50 Float
1.01 0.05
0.04 0.01
0.00 0.01
0.06 0.06
1.11 0.13
168.26 57.97
1.70 0.03
0.07 0.01
0.00 0.01
0.10 0.03
1.87 0.08
0.01
0.06
0.07
98.6
98.9
Sink
1:02
0.04
0.00
0.21
1.27
171.68
1.75
0.07
0.00
0.36
2.18
"Calculated for 40 mesh fraction.
-------
TABLE 45.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN KENTUCKY
NO. 9 COAL (Continued)
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, °F/min
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
NJ Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
f. No. 9 -
7!
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
50
0
04
10
54
38
06
84
16
16
04
09
40
25
78
04
10
54
38
06
.6
BR-76-3
0:
1
5
1500
30
Feed Residue
0.04
0. 10
1. 54
1. 38
3.06
75.0
90.84
0.04
0.09
1.40
1. 25
2.78
0.04
0. 10
1. 54
1.38
3.06
0.12
0.00
0.02
0. 37
0. 51
51.7
31.1
31.1
62.62
0.08
0.00
0.01
0. 23
0. 32
0.02
0. 37
0. 39
91.4
93.1
W. Ky. No. <
Feed
0. 01
0. 03
0. 52
0. 46
1. 02
150
272. 52
0. 04
0.09
1. 40
1. 25
2. 78
0.01
0. 03
0. 52
0. 46
1.02
+50
0. 22
0. 01
0. 02
0. 17
0. 42
53. 17
0. 12
0. 01
0. 01
0. 09
0. 23
0. 02
0. 17
0, 19
96. 4
97. 1
BR-76-4
2:1
5
1500
30
-50 Float
1.29 0.
0.05 0.
0.00 0.
0. 04 0.
1. 38 0.
1 n 7
168. 29 49.
2.17 0.
0.08 0.
0.00 0.
0. 07 0.
2. 32 0.
0.
0.
0.
93
95
10
00
01
32
43
68
05
00
01
16
22
01
32
33
. 9
. 1
Sink
1.30
0.03
0.00
0.08
1.41
171.78
2. 23
0. 05
0. 00
0. 14
2.42
*Calculated for 40 mesh fraction.
-------
TABLE 45.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN KENTUCKY
NO. 9 COAL (Continued)
Run No.
Lime/Coal Feed Ratio
Coal
Heating Rate, °F/min
Terminal Temperature, F
Holding Time", min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
' Total
Weight, g
Initial
Treated
Weight Loss, %
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
'Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
Feed
0.
0.
1.
1.
3.
100.
0.
0.
1.
1.
3.
0.
0.
1.
1.
3.
Coal*
02
60
06
82
50
00
02
60
06
82
50
02
60
06
82
50
+40 Mesh
Pretreated Coal
/. No. 9 -
7
3
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
20
50
0
04
10
54
38 -
06
84
16
16
04
09
40
25
78
04
10
54
38
06
.6
BR-76-5
0
:1
20
1500
240
Feed Residue
0.
0.
1.
1.
3.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
75
84
04
09
40
25
78
04
10
54
38
06
0. 26
0.01
0.02
0. 27
0. 56
41. 3
44. 93
44. 93
50.02
0.13
0.01
0.01
0. 14
0. 29
--
--
0.02
0. 27
0. 29
94.6
95.7
Jtreated W. K}
Feed
0.01
0.03
0. 52
0.46
1.02
150
272. 52
0.04
0.09
1.40
1. 25
2.78
0.01
0.03
0. 52
0.46
1.02
+50
0. 13
0.00
0.00
0.09
0. 22
53. 96
0.07
0.00
0.00
0.05
0. 12
--
--
0.00
0.09
0.09
98.2
98.6
BR-76-6
2:1
20
1500
240
-50 Float
1.02 0.06
0.01 0.01
0.00 0.03
0.02 0.19
1.05 0.29
ai
162.97 48.01
1.66 0.03
0.02 0.00
0.00 0.01
0.03 0.09
1.71 0.13
--
..
0.03
0. 19
0.22
96.4
97.1
Sink
0. 95
0.03
0.00
0.02
1.00
168.92
1.60
0.05
0.00
0.03
1.68
^-Calculated for 40 mesh fraction.
-------
TABLE 45.
BATCH REACTOR TEST RUN DATA FOR PRETREATED WESTERN KENTUCKY
NO. 9 COAL (Continued)
Run No. Feed Coal
Lime/Coal Feed Ratio
Coal
Heating Rate, F/mtn
Terminal Temperature, F
Holding Time, min
Sulfur, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
ro Weight Loss, °1,
Total Weight
Coal Weight
Reduced Data
Weight, Ib
Sulfur Weight, Ib
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content %
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Removal, wt %
From Feed
From Coal
*Calculated for 40 mesh fraction.
+40 Mesh
Pretreated Coal
750
30
0. 02
0. 60
1.06
1. 82
3. 50
100. 00
0. 02
0. 60
1.06
1.82
3. 50
0. 02
0. 60
1. 06
1. 82
3. 50
0.
0.
1.
1.
3.
90.
9.
9.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
84
16
04
09
40
25
78
04
10
54
38
06
BR-76-7
0
:1
Rapid
1500
330
Feed Residue Feed
0.
0.
1.
1.
3.
90.
0.
0.
1.
1.
2.
0.
0.
1.
1.
3.
04
10
54
38
06
75
84
04
09
40
25
78
04
10
54
38
06
20. 6
0.22
0.00
0.02
0. 14
0. 38
51. 2
31.7
a I 7
62.01
0. 14
0.00
0.01
0.09
0.24
0.02
0.14
0.16
96.4
97.1
0. 01
0. 03
0. 52
0.46
1.02
150
272. 52
0. 04
0.09
1.40
1. 25
2. 78
0. 01
0. 03
0. 52
0.46
1.02
+50
0. 13
0. 01
0. 00
0. 12
0. 26
40. 81
0.05
0.00
0.00
0. 05
0. 10
--
--
0.00
0. 12
0. 12
98.2
98. 6
BR-76-8
2:1
Rapid
1500
330
-50 Float Sink
1.26 0.
0. 01 0.
0.00 0.
0.03 0.
1.30 0.
156.13 35.
1.96 0.
0.02 0.
0.00 0.
0.05 0.
2.03 0.
0.
0.
0.
12 1.
02 0.
02 0.
14 0.
30 1.
71 161.
04 2.
01 0.
01 0.
05 0.
11 2.
02
14
16
35
03
00
03
41
23
18
05
00
05
28
97. 8
98. 3
B76051098
-------
COAL COMBUSTION METHODS
The following discussion is presented to indicate the applicability of the treated,
low-sulfur solid fuel in various types of combustion equipment. Several methods exist for
burning solid fuels. These methods are divided into two basic groups: fuel bed and
suspension burning.
The term "fuel bed" aptly describes the technique. A bed of burning fuel is
supported by a grate, screen, or similar device, depending upon the circumstances. Part,
and sometimes all, of the air for combustion flows through the grate to provide cooling
to the metal parts. Fuel replenishment is normally provided by mechanical means. Ash
or residue, in larger units, is also discharged either by mechanical movement or by the
physical arrangement of the bed.
In an underfeed, single-retort type of burner, a mechanical cam or similar
apparatus pushes fuel toward the end of the stoker and upward into the fuel bed. The bed
is sloped away from this point, and the burning coal moves away from the feed point by
gravity so that ash and residues are dumped at the side. Air flows upward through the
bed. This kind of stoker has low capacity and will handle most bituminous coals and
anthracite. Preferable coal sizing is from 3/4 inch to 2 inches, with no more than 50% at
less than 1/4 inch.
A multiple-retort stoker has several lanes, or retorts, formed by pairs of sloping
grates or tuyere stacks. Fuel is forced into the lanes, as with the single retort, and air is
admitted along the tops of the grates. In some cases, the grates are given slight motion
to agitate the bed for better burning and for residue dumping. This kind of stoker is best
suited to caking coals with relatively high ash-softening temperatures. Coal sizing is up
to 2 inches, with 30% to 50% through a 1/4-inch screen.
Grate stokers can be oscillating, dumping, moving, or stationary. They are of the
cross-feed or overfeed type. In the cross-feed type, fuel is fed by gravity onto the grate
and into the furnace. In the overfeed, or spreader type, the fuel is propelled into the fur-
nace, and 30% to 50% of it is consumed while suspended above the bed. The remaining
fuel falls to the bed to be burned. A spreader-feed-type stoker has the disadvantage that
sometimes the ash can have a carbon content of 30% to 50% and must be recycled to
achieve better fuel efficiency.
In all the grate stokers, air flows upward through the grate, to provide cooling,
and into the feed bed. Additional air may be provided above the bed. Dumping of ash
and residue depends on the type of grate. A stationary grate must be divided into zones
for the burning and ash removal. The grates themselves can be dumped in a dumping-
grate stoker, which eliminates the mechanical or hand holing of ashes. With travelling or
oscillating grates, the bed is mechanically moved to the end opposite the feed, where the
123
-------
residue is dumped. A greater heat release, because of less ash on the grates, has made
these two mechanical stokers more economical. Grate stokers are widely used because
they can burn all types of coal from anthracite to lower rank bituminous coal and lignite.
Considering the characteristics and requirements of fuel beds, they would not be
recommended for the proposed low-sulfur fuel unless the fine, desulfurized solids were
first briquetted. Fuel capacity would rule out the single-retort stoker, and coal sizing
would do the same for both of the retort-type stokers. Their fuel-particle-size
requirements are much larger than the proposed low-sulfur fuel as produced directly.
Also, if lime is used and not separated from the fuel before burning, the feeding and
residue-removing systems must be larger to handle the increased ash load. The grate
stokers could possibly use this fuel, but, once again, the particle size must be increased if
lime is used and not separated. Another drawback is that because most of the air flows
upward through the grate, some fluidization may occur in our small-sized fuel (unless
briquetted). Overall, stoker-type fuel beds are not readily adaptable to this fuel and
would probably require special design considerations.
Suspension burning means that pulverized fuel is burned while suspended in air or
gas (unsupported mechanically). This type of combustion is used more extensively in the
United States than the coarse-coal fuel beds. A greater steam-generating capacity is
afforded by this method. Suspension burning is independent of coal-caking character-
istics, and load changes can be made quickly. Several burner arrangements and firing
methods are possible.
A fantail, vertical-firing method has a U-shaped flame. In this type of burner the
fuel and primary air (used for coal transport) are forced downward into a vertical burning
chamber. Secondary air for combustion is introduced at the sides of the chamber and
shapes the U. Low-volatile chars or fuels with less than 15% volatiles are especially
suited for this type of combustion because the fuel stream is projected well into the
furnace before the introduction of the bulk of the combustion air.
The cyclone firing method uses a coarser coal, usually 4 mesh. The primary air
and coal are admitted into the cylindrical chamber tangentially, but independent of the
secondary air. Finer particles are burned in suspension, while the larger ones are thrown
to the wall. A sticky coating of molten slag catches these particles and retains them
until they are burned. Slag is continuously drained and quenched.
In other types of burners, the primary air used to transport the coal is about 20%
of the total required. The secondary air is mixed with the coal and primary air in the
burner and then enters the furnace. Burner arrangement usually depends on the
requirements of the system. These types are normally associated with more highly
volatile fuels with higher volatile counts.
In the last few years, another, more sophisticated type of suspension burning has
been put into use fluidized-bed combustion. The fluidized-bed combustor is a vertical
vessel of appropriate size. Air enters a chamber in the bottom and flows upward through
a distribution plate. The air-flow rate is controlled so that the fuel is fluidized and
burned while suspended. Coal is introduced into the bed above the distribution plate, and
residue is discharged continuously. The location of the feed and discharge points depends
on the fuel, bed size, etc. Heat is transferred to an absorption surface, usually steam
tubes that are located within the fluidized bed. Internal cyclones are used for removing
dust from exit gases, and the fines are returned to the bed. Fluidized beds have several
124
-------
advantages. They run at lower temperatures, which results in less formation of nitrogen
oxides and in the retention of some^sulfur in the residue of some types of coal. Higher
heat-transfer rates are possible with the transfer surface immersed in the bed. A
pressurized system would also operate more efficiently than an atmospheric one.
Some of the suspension systems lend themselves to the proposed low-sulfur fuel
more readily than the stoker types. Because of our proposed small-particle size, the
fuel^uspension is easier. The vertical fantail, cyclone, or fluidized bed should be able to
handle" the fuel without much change from regular coal burning if the lime is-separated
before combustion. If the lime is left in for ^combustion, some size changes would be
necessary, as well as an increase of fluid!zing air. The units would be designed so that
the lime could be collected and disposed of or recycled.
If it is decided to use lime in the process, two points must be considered to
determine if the lime should be separated before burning. The first is whether it will be
possible to maintain combustion and temperatures with the larger amount of inert
material in the combustor; the second is the evaluation of the disposition and final form
of the sulfur, captured by the lime during hydrogen treatment. At present, we do not
know if that sulfur will be retained by the lime as CaSO^, if it wilTbe discharged as SO^,
or if the lime has sufficient capability to capture additional sulfur during combustion.
Both of these questions will require investigation; however, they become academic if it is
decided not to use lime in the hydrogen-treatment step of the process.
125
-------
ECONOMIC STUDIES
A conceptual process design has been prepared. Material and heat balances were
calculated fora 20,000-ton/day facility (Figure 19) and the plant cost was estimated by
conventional engineering-factoring techniques. The process design basis was the system
without the sulfur acceptor present, as.defiried from small-scale tests. Concurrent with
this economic study, the large-scale experimental program determined that the acceptor
was indeed required and the effects upon the overall process were approximated.
The design basis for the pretreater section of the facility was taken largely from
this work, with definition of the off-gas composition and heat release determined from
other, parallel programs at the contractor's pilot plant. The hydrodesulfurizatipn ,
temperature, residence time, sulfur removal, and carbon conversion were developed from
the data reported here; the off-gas composition, benzene production, =and energy
requirements were developed from the contractor's in-house data base on hydropyrolysis
and hydrogasification.
PROCESS DESIGN RESULTS
Run-of-mine coal (Western Kentucky No. 9) is fed at a rate of 20,000 tons/day.
The coal is continuously stored, reclaimed from storage, and crushed to 14 mesh. The
coal is then pretreated in a fhiidized-bed reactor at 750°F, consuming 1 SCF Oo/lb coal.
In this unit, 242.4 million Btu/hr is recovered to generate 1200 psig steam. The
pretreater off-gas, with a higher heating value of over lOOBtu/SCF, has a flame
temperature of about 2600°F (partially because of the 750°F initial temperature). This
gas is partially used as process fuel where direct-fired heating is required,..and the
remainder is used to fire a power plant boiler. The power plant generates 155,000 kW, of
which 95,700 kW is exported (as by-product). Boiler fuel gas is scrubbed to recover SO2>
which is sent to a sulfuric acid plant. The plant requires 3835 gpm of raw water for
cooling tower and boiler feedwater makeup.
The pretreated coal is sent to a fhiidized-bed reaction vessel (the hydrodesulfur-
ization reactor) where it is desulfurized in a 50% hydrogen atmosphere. The reactions
are endothermic and require 406.4 million Btu/hr of heat addition. The treated solid fuel
product leaves the reaction vessel at 1500°F and is cooled in a rotary-kiln-type device
where 342.5 million Btu/hr of heat is recovered.
The reactor off-gas is cooled to 200°F in a waste-heat recovery unit (recovering
406.9 million Btu/hr). The gas is then scrubbed in a venturi-type scrubber for dust
removal. After cooling to 100°F and removal of condensed water, the gas is compressed
to 35 psig for acid-gas removal. The acid-gas is sent to an H^S burner where this SO2
product is combined with the SO£ from the pretreater off-gas and converted to
1928 tons/day of H2SO4 (100%). The sweet gas from the acid-gas removal unit is split
into co-product gas (66 billion Btu/day) and gas required for recycle to the fhiidized-bed
reactor. The hydrogen content of this recycle gas is raised from 39% to 50% by steam
reforming a slipstream of the recycle gas.
126
-------
The recovery of the energy in the feed coal is as follows:
Solid Fuel Product 61.3%
Co-Product Fuel Gas (570 Btu/SCF) 14.0%
Light Oil By-Product 7.0%
Exported Power 1 .7%
Recovered Energy 84.0%
Additionally, the facility will recover about 150 to 300 tons daily of anhydrous ammonia
with additional heating value. (However, its major market will not be for fuel purposes.)
PROCESS ECONOMICS
Capital and operating costs are shown in Tables 46 and 47. The price of treated
product is calculated using utility type financing at $30/ton, or about $1.25/million Btu.
The basis for this calculation is shown in Table 48. Total capital required for the
20,000-ton/day plant is $437 million. In order to make the process economically feasible,
considerable capital has to be spent on equipment to recover by-products and convert the
pretreater off-gas into power. This amounts to about $90 million (or about 40% of the
installed plant cost) including capital spent for power generation by burning pretreater
off-gas at about $50 million.
The project contingency has been increased to 30% because of the following
factors. The internals of the hydrodesulfurization reactor's materials of construction is
an area of uncertainty because of the severe environment: a minimum temperature of
2600°F, with sulfur-containing combustor gas inside the tubes and a 1500°F fluidized
bed, fluidized by a 50% H, gas on the outside of the tubes. In addition, both ammonia
and COS may be produced and require more downstream processing. Other hydro-
desulfurization off-gas composition uncertainities also affect the project contingency.
The normal contingency used is 15%; in this case 15% process development contingency
has been added to this. This is about double the hydrodesulfurization reactor cost and
increases total capital required by $47 million.
Operating Costs
Coal is priced at $1.00/million Btu and is the major operating cost. Gross
operating costs are $185 million per year. This is largely offset by the significant
amount of by-product credit, $119 million, for a net operating cost of $66 million per
year.
By-product credit unit costs are
Power: 2.5$/kWhr
H2SO4: $34/ton of 100% acid
Medium-Btu gas: $2.30/million Btu
Benzene: 35tf/gal.
Escalated from $2.26/million Btu to $2.30 because of time difference.
Data source: "Economics of Current and Advanced Gasification Process
for Fuel Gas Product," EPRI AF-244, Project 239 Final Report, July
1976.
127
-------
oo
!928 ton/day
flOO% H2S04
ROM COAL
COAL
STORAGE
AND
PREPARATION
FUEL
TO
PROCESS
20,000 ton/flay
S02 493 mol/hr
FROM PROCESS FUEL USERS
155,000 kW GENERATED
59.300 kW CONSUMED
PRETREATER FINES
15.925 Ib/hr
PRETREATER PRODUCT
OIL 20,410 Ib/hr
95,700 kW EXPORT POWER
STEAM FROM
PROCESS WHR
BOILER FEEDWATER
a - 247,600 Ib/hr
1200 psig
SATURATED STEAM
HYDRO-
DESULFURIZER
4483 mol/hr H20
TO WASTEWATER
TREATMENT
REACTOR FUEL
406.4 X 10° Btu/hr
0.TO S02 REMOVAL
24,675 mol/hr
DUTY
30.1 X I06
Btu/hr
406 gal/min
TO BOILER
FEEDWATER
TREATMENT
DUTY
54.7 X I06 Btu/hr
FLUIDIZING RECYCLE HEATER
WINDAGE AND
EVAPORATION LOSS
3622 gal/min
HEAT RECOVERED
342.5 X I06 Btu/hr
160 gal/min
FROM PROCESS
97,900 gal/min
SLOWDOWNS
33 gal/min FROM
STEAM SYSTEM
97,900 gal/min
VBLOW DOWN
979 gal/min FROM
COOLING TOWER
<6> COPRODUCT
GAS
66XI09Btu/doy
570 Btu/SCF
STEAM
38,000 Ib/hr
REFORMER FUEL
113.8 X I06 Btu/hr
WASTEWATER TREATMENT
^1172 gal/min
TREATED PRODUCT
12,081 ton/day
11.925 Btu/lb(HHV)
Figure 19. Coal desulfurization process (Western Kentucky coal, feed rate 20,000 tons/day).
-------
NJ
VO
Stream Description
Stream Number
Temperature, °F
Pressure, psia
Component, mol/hr
CO
C02
H2
H20
CH4
N2
H2S
C2»6
C3H8
C4H10
C6H6
°2
so2
Total
Pretreater
Off-Gas
1
750
20
888
3217
137
7569
915
19696
,
577
384
238
778
439
34888
Hydro -
Treater
Off-Gas
2
1500
20
2716
1677
7618
4761
7764
591
1153
970
27250
Stream Des
Off-Gas
to Acid-
Gas
Removal
3
100
50
2716
1677
7618
417
7764
591
1153
21936
icription
. Feed to
Sulfuric
Acid
Plant
4
100
25
931
82
1153
2166
Sweet
Gas
5
115
45
2716
746
7618
196
7764
591
19631
CO
Product
Gas Recycle
6 7
115 115
43 43
1765 951
485 261
4949 2669
128 68
5044 2720
384 207
12755 6876
Pretreater Pretreated
Feed Coal
Stream Number
Component
A
B
Reformer
.Feed
8
115
43
287
79
804
21
819
62
2072
Treated
Product
C
Fluid-
Reformer Reformer izlng
By-Pass Product Recycle
9 10 11
115 1500 820
43 25 25
664 787 1451
182 380 562
1865 3513 5378
47 1161 1208
1901 17 1918
145 62 207
4804 5920 10724
Composition, X (Dry)
C
H
0
N.
S
Ash
70.00
4.54
8.95
1.53
3.74
11.24
70.67
3.80
8.54
1.33
3.10
12.56
80.04
0.92
0.49
0.75
0.58
17.21
Total, Ib/hr
1,666,667* 1,373,367
1,006,7.73
* Includes 96,667 Ib/hr moisture.
A77091991
Figure 19. Coal desulfurization process (Western Kentucky coal, feed rate 20,000 tons/day).
(Continued)
-------
TABLE 46. CAPITAL INVENTMENT SUMMARY
MID-1975
$106
Coal Storage and Preparation 13.4
Pretreatment 8.9
Hydrodesulfurlzation 17.0
Char Cooler 9.3
Waste Heat Recovery 12.6
Gas Cooling and Dust Removal 4.0
Benzene Removal 14.6
Process Heaters 2.0
Reformer 4.7
Acid-Gas Removal and Compressors 11.1
Sulfuric Acid Plant 15.1
SO- Removal Unit 13.3
Boiler 31.8
Turbine Generator 18.8
Electric Power Distribution at $170/kW; 59,300 kW 10.1
Cooling Towers & Plant Makeup Water 3.3
Waste Water Treating 4.8
Particulate Emission Control 3.7
General Facilities 22.1
Installed Plant Cost, Excluding Contingencies 220.6
Contingency 15% + 15% Process Development Contingency = 30% 66.2
Total Bare Cost 286.8
Contractors Overhead and Profits (15%) 43.0
Total Plant Investment (TPI) 329.8
Interest During Construction (9% X 1.875 years X TPI) 55.6
Start-up Cost (5% of TPI) 16.5
$106
Working Capital: a) 60 days coal at $20/ton 28.2
b) 0.9% of I 3.0
c) 1/24 of Treated Product Gas at
$1.00/106 Btu 3.9
35.1 35.1
Total Capital Required 437.0
130
-------
TABLE 47. ANNUAL OPERATING COSTS
$106/yr
Operating Cost Components
Coal Coat
20,000 tons/day, 328,5 days/yr, at $1.00/106 Btu
($23.497ton) 154.329
Other Direct Materials ' 0.058
Catalyts and Chemicals 1.533
Purchased Utilities
Raw Water 3835 gpm at $0.45/1000 gal 0.816
Labor
(a) Process Operating Labor 37 men/shift X
$7.20/hr X 8760 hr/yr 2.334
(b) Maintenance Labor 1.5% of TPI 4.947
(c) Supervision 15%. of. (a) + (b) 1.092
(d) Administration and General Overhead
60% of (a) + (b) + (c) 5.024
Supplies
Operating [30% of (a)] 0.700
Maintenance 1.5% of TPI 4.947
Local Taxes and Insurance 2.7% of TPI 8.905
Total Gross Operating Cost 184.685
By-Product Credit
Power: 95,700 kW X 328.5 X 24 hr X.$.025/kWr = .862
H2S04: 1928 tons/day X 328.5 day/yr X $34/ton = 21.534
Medium-Bt.u/gas: 66 X 109 Btu/day X 328.5 days/yr
X $2.30/106 Btu = 49.886
Benzene: 970 mol/hr X 24.hr/day X 7 40 ib/gal
X 328.5 days/yr X $0.35/gal = 28.289
118.551 (118.551)
Net Operating Cost 66.134
Product Price, Utility type financing
66.134 + 0.1198 (437) + 0.0198 (35.1) = 119.181 X 10& = 630037,-
12,08.1 tons/day X 328.5 days/yr 3,968,609 tons/yr (utiuty-type
-------
to
NJ
TABLE 48. GAS COST CALCULATION BY UTILITY METHOD USED IN THE "FINAL REPORT OF
THE FPC SUPPLY-TECHNICAL ADVISORY TASK FORCE - SYNTHETIC GAS-COAL"
BASIS
Project Life
Depreciation
Debt/Equity Ratio
Return on Equity
Interest Rate on Debt
Federal Income Tax
Interest During Construction
OTHER FACTORS
Plant Stream Factor
Contingencies
Contractor's Overhead and Profits
Start-up Cost
Working Capital
UTILITY METHOD
20 years
5%/year, straight line
75%/25%
15%
9%
48% i
Interest Rate (9%) X 1.875 years
X total plant investment
90%
30% of installed plant cost (includes process development contingency
of 15%)
15% of total bare costs
5% of total plant investment
a) Coal inventory (60 days feed at full rate)
b) Material and supplies (0.9% of total plant investment)
c) Net receivables at 1/24 X annual revenue required
Derived equation
20-year average gas price, $/10 Btu =
Where
N = Net annual operating cost
C = Total capital required
W = Working capital
G = Annual treated product production
N + 0.1198 C + 0.0198 W
10% for 3 years, 90% for 1.75 years
-------
The power credit is conservatively estimated, based on costs from a large, new power
plant. The acid price is about 70% of market price. The price of the 570 Btu/SCF gas
was set at $2.30/million Btu to be conservative. This is a price that was obtained from a
study employing a modern fluidized-bed technology for producing low-Btu gas. In this
study, coal was priced at $1.00/million Btu, and the time basis was mid-1975 for capital
costs. The medium-Btu gas in this study probably could be sold for more than this. Ben-
zene quality is unknown so 44% of value price was used.
Product Price Sensitivities
A change of $10 million in total capital required results in a treated product price
change of 42$/ton or 14
-------
conservative estimated basis employed, the process produces a clean fuel that is
significantly less costly than alternatives.
ECONOMIC STUDIES - CONCLUSION
Based on preliminary economic analysis, the commercial-scale process appears to have economic potential
for the production of an environmentally-preferred solid'fossil'fuel. Product prices (mid-19 75 basis) are anticipated
to be about $1.25to$l. 75/million Btu.
134
-------
PROCESS DEVELOPMENT UNIT (PDU) REQUIREMENTS
A conceptual design and initial equipment specification have been prepared for a
Process Development Unit (PDU) for the coal desulfurization process. This unit is
designed to incorporate the major features of the process and to operate on an integrated
basis, at a 10 tons/day feed rate, to prove the technical feasibility of the system. The
design is not detailed; additional data are required from the 10-inch-diameter unit before
this detail can be developed. Rather, this initial design is presented to indicate the type
of experimental equipment that would be necessary for such a system (as contrasted to
the commercial plant concept discussed earlier). Figures 20 and 21 and Tables 49 and 50
present the process configuration.
CONCEPTUAL DESIGN
Coal, as received by railroad car or truck, is put into a storage bin to prevent
weathering by the elements. Proper sizing is done by screening, grinding the oversize,
and rescreening. The coal after screening goes to the feed bin for use in the process.
A variable-speed screw conveyor feeds the coal into the pretreater at the selected
rate. The pretreater is equipped with a start-up heater, to reach the operating tempera-
ture, and a fan or compressor, to supply air for fluidization and reaction. Dust is
removed from the off-gases by an internal cyclone that returns the fines to the bed; the
vaporized tars, oils, and lovv-Btu gas are consumed by flaring. Pretreated coal is taken
from the bed to storage before feeding to the hydrotreatment section.
In the hydrotreatment section the acceptor is stored in a feed bin for use in the
system. Acceptor is fed either directly into the hydrotreater or it can be put into the
pretreater coal feed system in the proper ratio of acceptor to coal. The hydrodesul-
furizer is equipped with a heater to aid in start-up and to supply heat during operation if
necessary. Hydrogen is also preheated before introduction to the hydrodesulfurizer.
Solids are removed from the gases and returned to the bed by an internal cyclone.
The hydrotreater off-gases are cooled, scrubbed by di-glycol-amine (DGA) for
sulfur and CO-, removal, and split into two streams. One stream of the purified off-gas
is sent to the incinerator and the other is recycled to the hydrotreater. Fresh EU is used
as makeup to keep the H-> pressure in the recycle gas at the proper value.
The char-acceptor mix is quenched and put through a magnetic separator. The
acceptor is sent to a steam regenerator and provision is included for recycling to the
feed bin. The treated solid fuel is discarded after sampling.
Table 51 lists the required capacities for the equipment in the pretreatment
section. The raw coal storage bin is sized for 30 tons of coal, an equivalent of 3 days'
run. The screening, milling, and recycle systems are sized so that feed material can be
prepared in a relatively short time. Capacity for the pretreater feed bin is also 30 tons,
enough for a 3-day run. The feed screw to the pretreater is capable of 0 to 2 tons/hr,
which gives us the desired flexibility to adjust holding time in the system for various
135
-------
TO
ATMOSPHERE
PRETREATEO
COAL
STORAGE
TO
HYDROTREATER
A7804IOI5
Figure 20. Pretreatment section.
TABLE 49. PRETREATER STREAMS
Stream
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
CO
°2
C02
H2
CH4
C3H8
C4H1Q
>C5
96.9
590.5
39.6
34.3
12.9
75.8
850.0
Ib/hr
mol/hr
2.24
90.9
543.9
30.3
25.5
12.2
69.4
772.2
5.9
13.8
0.7
0.8
0.3
3.6
25.1
0.450
0.054
0.646
0.061
0.231
0.088
0.044
0.151
8.43
8.43
136
-------
HEATER
FLUE TO
VENT
TO
ATMOSPHERE
REGENERATOR
STEAM
REGENERATED
SIDERITE
A7804IOI4
Figure 21. Hydrotreatment section.
TABLE 50. HYDROTREATER STREAMS
Stream
B
Ib/hr
Ash
Carbon
Hydrogen
Sulfur
Nitrogen
Oxygen
Total
90.9
543.9
30.
25.
12.2
69.4
772.2
90.9
437.3
6.9
3.2
5.3
8.9
552.5
CO
C02
H
2
CH,
C2H6
mol/hr
15.07
14.66
316.62
1.01
10.04
0.22
137
-------
TABLE 51. PRETREATER EQUIPMENT LIST
Equipment
1. Raw Coal Storage
2. Screen Feed Screw
3. Screener (single deck)
4. Mill
5. Recycle System
6. Coal Elevator
7. Feed Bin
8. Feed Screw
9. Pretreater
10. Air Compressor
11. Cyclone
12. Flare
13. Start-up Heater
14. Pretreater Coal Storage Bin
Capacity
30 tons
0-5 tons/hr
15 tons/hr
10 tons/hr
10 tons/hr
5 tons/hr
30 tons/hr
0-2 tons/hr
850 Ib/hr
10,000 SCF/hr at 5-10 psig
400 ACF/min at 750°F
400 ACF/min at 750°F
(2110 Btu/SCF)
0.5 X 106 Btu/hr
30 tons
138
-------
coals. A residence time of 1 hour in the pretreater with 1 SCF O-,/lb of coal gives a bed
requirement of ,3.0-feet diameter by 4.5 feet height and an air-flow ,of 4125 SCF/hr. The
remainder of the fluidizing gas can be made up with steam.- If a coal is used requiring
more severe pretreatment, the bed height, and therefore residence-time, must be
increased. Provisions must be made, then, for an increase in bed depth, and also the
height must be such that the cyclone can be internally mounted. The cyclone would be
about 1 foot in diameter by about 4 feet tall. This indicates a pretreater 3 feet in
diameter by at least 15 feet tall to accommodate a possible 9-foot tall bed and the
cyclone with dipleg. The startup heater should have an input of 0.5 million Btu/hr. Off-
gases would be consumed in a flare designed to also burn the intermediate-Btu by-
product gas from the hydrotreater.
Pretreated coal would be fed to the hydrotreating system. Equipment lists and
capacities for this section are shown in Table 52. Acceptor, if used, would be added
either to the.hydrotreater or into the pretreated coal feed system. An acceptor feed bin
of 30 tons would supply 3 days at a 1:1 acceptor-to-coal weight ratio. The acceptor feed
system should be capable of 0 to 2 tons/hr to cover a range of acceptor ratios. At a
1:1 ratio the hydrodesulfurizer must handle 1544 Ib of mix per hour. A 3-hour residence
time and fluidization velocities of up to 3 ft/s for the siderite requires a bed 7 feet in
diameter and about 3.5 feet tall. The overall height of the vessel must be such that an
internal cyclone can be included. To handle the hydrogen flow at the operating tempera-
ture the cyclone is 3.5 feet in diameter and 14 feet long. The overall hydrotreater should
be 7 feet in diameter and 20 feet tall to accommodate the cyclone.
Off-gases are cooled by a cooler with a capacity of 4 million Btu/hr, then,
scrubbed with DGA. A slipstream of gas is pulled off, the amount determined by the gas
analysis, to be flared. Makeup hydrogen is added to keep the partial pressure hydrogen in
the hydrodesulfurizer feed gas at desired values. Solid material is quenched and then
separated magnetically. Provision has been included for the acceptor to be regenerated
by steam and recycled.
Heat for the process comes from the hydrogen heat at 4 million Btu/hr and an
auxiliary process heater of 0.5 million Btu/hr.
This PDU will produce approximately 13,250 pounds of treated fuel, depending
upon feed coal characteristics, from 10 tons of coal per day.
This unit is designed for experimental purposes to prove the technical feasibility
of the integrated system. It is not the fully integrated plant that was conceptualized for
the commercial analysis. For example, low- and intermediate-Btu by-product gases are
flared, rather than recovered for energy value; wastewater treatment is not included;
and makeup hydrogen is used rather than treating a portion of the recycle gas for use.
Rather, the PDU is designed for data acquisition on the key elements of the system.
139
-------
TABLE 5Z. HYDROTREATER EQUIPMENT LIST
Equipment
1. Acceptor Feed Bin
2. Acceptor Feed Conveyor
3. Hydrodesulfurizer
4. Char-Acceptor Discharge Conveyor
5. Solids Quench
6; Magnetic Separator
7. Regenerator
8. Regenerated Siderite Conveyor
9. Gas Cooler
10. Scrubber-DGA for CO
11. Flare
12. Hydrogen Compressor
13. Hydrogen Heater
14. Process Heater
Capacity
30 tons
0-2 tons/hr
1544 Ib mix/hr
0-2 tons/hr
0.75 X 106 Btu/hr
1325 Ib/hr
772 Ib/hr
772 Ib/hr
4 X 106 Btu/hr
2000 SCF/min
Use Pretreater Flare
2000 SCF/min at 5-10 psig
4 X 106 Btu/hr
0.5 X 106 Btu/hr
140
-------
FUTURE WORK
Assessment of the data now available, .including .the economic analysis, indicates
that the process has merit for convertingrcoal into a solid fossil/fuel that can be directly
consumed in accordance with present erivirorimental regulations." The suggestions for
future work include the following.
10-INCH-DIAMETER UNIT
The data/from the continuous-feed, 10-inch-diameter reactor ^are insufficient to
prove the process on that scale. Additional, testing is required,, with alternative sulfur-
acceptor materials included in the system.
ACCEPTOR'REGENERATION
Experimental data are required to prove the regeneration processing required for
the preferred sulfur acceptor, or applied to this overall process. .
PROCESS DEVELOPMENT UNIT
.The-Process Development Unit (PDU):described in.this report, or a"variation
thereof/as determined by the experimental-program outlined above, should.be con-
structed and operated to prove the technical feasibilityof -the process on an integrated,
systematic basis. -
141
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-79-016
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Evaluation of the Flash Desulfurization Process for
Coal Cleaning
5. REPORT DATE
January 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Donald K. Fleming and Robert D. Smith
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Institute of Gas Technology
3424 South State Street
Chicago, Illinois 60616
10. PROGRAM ELEMENT NO.
1AB013; ROAP 21AFJ-40
11. CONTRACT/GRANT NO.
68-02-2126
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 11/75 - 6/77
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES iERL_RTp project officer is Lewis D. Tamny, Mail Drop 61, 919/
541-2709.
16. ABSTRACT
The report gives results of a program to develop (on the laboratory, bench,
and pilot scale) operating conditions for key steps in the 'flash' process for desulfu-
rizing coal by chemical and thermal treatment. Laboratory and bench scale data on
high-sulfur eastern U.S. coals prove that the process can reduce sulfur to the point
that the resulting solid fossil fuel can be directly consumed in compliance with cur-
rent regulations for SOx emissions. Because of operating and technical difficulties,
pilot scale test data are inconclusive. A preliminary analysis of a conceptual process
indicates that the treated fuel would cost $1. 50 to 1. 75/million Btu (in 1977 dollars on
a utility financing basis) if the initial coal cost is $1. 00/million Btu. Four eastern
U.S. coals, from abundant seams, were treated under various reducing-gas atmos-
pheres at elevated temperatures. Sufficient sulfur was removed from all coals tes-
ted at ambient pressure and at temperatures of 1500 F and residence times of 60
minutes. These data were obtained in laboratory, fixed-bed, continuous weighing
reactors and bench-scale fluidized-bed systems. As conceived, the process incor-
porated a 'sulfur-getter'a material (e.g. , lime) that has a greater chemical affi-
nity for the sulfur than the coal has. Use of a sulfur-getter is required to reduce the
H2S concentration in the gas. Data indicate that the concept is sound.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Coal Preparation
Cleaning
Desulfurization
Pollution Control
Stationary Sources
Flash Desulfurization
Chemical Treatment
Thermal Treatment
13B
081
13H
07A,07D
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
153
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
142
------- |