&EPA
           United States
           Environmental Protection
           Agency
          Office of Air Quality
          Planning and Standards
          Research Triangle Park NC 27711
EPA-450/3-79-012
March 1979
           Air
A Review of Standards
of Performance for New
Stationary Sources -
Portland Cement Industry

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                             EPA-450/3-79-012
  A Review of Standards
 of Performance for  New
    Stationary Sources  -
Portland Cement  Industry
                  by

               Kris W. Barrett

         Metrek Division of the MITRE Corporation
           1820 Dolley Madison Boulevard
             McLean, Virginia 22102
             Contract No. 68-02-2526



           EPA Project Officer: Thomas Bibb

        Emission Standards and Engineering Division
                Prepared for

        U.S. ENVIRONMENTAL PROTECTION AGENCY
           Office of Air, Noise, and Radiation
        Office of Air Quality Planning and Standards
        Research Triangle Park, North Carolina 27711

                March 1979

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This report has been reviewed by the Emission Standards and Engineering
Division, Office of Air Quality Planning and Standards, Office of Air, Noise
and Radiation, Environmental Protection Agency, and approved for publica-
tion . Mention of company or product names does not constitute endorsement
by EPA. Copies are available free of charge to Federal employees, current
contractors and grantees, and non-profit organizations - as supplies permit
from the Library Services Office, MD-35, Environmental Protection Agency,
Research Triangle Park, NC 27711; or may be obtained, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Springfield,
VA 22161.
                     Publication No. EPA-450/3-79-012
                                   ii

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                              ABSTRACT
     This report reviews the current Standards of Performance for New
Stationary Sources:  Subpart F - Portland Cement Plants.  It includes
a summary of the current particulate matter standard, the status of
current applicable control technology, and the ability of plants to
meet the current particulate matter standard.  No changes to the
existing standard are recommended, but EPA should continue evaluation
of sulfur oxide and nitrogen oxide controls with a view toward incor-
porating these emissions under the scope of the standard at a later
date.
                                 iii

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                          TABLE OF CONTENTS

                                                                 Page

1.0  EXECUTIVE SUMMARY                                           1-1

1.1  Best Demonstrated Control Technology                        1-1
1.2  Current Particulate Matter Emission Levels
     Achievable with Best Demonstrated Control Technology        1-2
1.3  Economic Considerations Affecting the NSPS                  1-3
1.4  Future Additions to the Standard                            1-3

2.0  INTRODUCTION                                                2-1

3.0  CURRENT STANDARDS FOR PORTLAND CEMENT PLANTS                3-1

3.1  Affected Facilities                                         3-2
3.2  Controlled Pollutants and Emission Levels                   3-2
3.3  Testing and Monitoring Requirements                         3-3
3.4  Regulatory Basis for Any Waivers, Exemptions, or
     Other Tolerances                                            3-4

4.0  STATUS OF CONTROL TECHNOLOGY                                4-1

4.1  Scope of Portland Cement Operations                         4-1

     4.1.1  Geographic Distribution                              4-1
     4.1.2  Technological Trends in Production                   4-4
4.2  Production of Portland Cement                               4-6
4.3  Particulate Matter Characterization                         4-10
4.4  Control Technology Applicable to the NSPS for
     Portland Cement Plants                                      4-17

     4.4.1  Cyclones                                             4-17
     4.4.2  Electrostatic Precipitators                          4-19
     4.4.3  Fabric Filters                                       4-21
     4.4.4  Gravel Bed Filters                                   4-22
     4.4.5  Wet Scrubbers                                        4-25

4.5  Comparison of Levels Achievable with Best
     Demonstrated Control Technology Under the Present NSPS      4-25

5.0  INDICATIONS FROM NSPS COMPLIANCE TEST RESULTS               5-1

5.1  Test Coverage in the EPA Regions                            5-1
5.2  Analysis of the NSPS Test Results                           5-1

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                    TABLE OF CONTENTS (Concluded)
                                                                 Page

     5.2.1  Control Technology Used to Achieve Compliance        5-7
     5.2.2  Analysis of Compliance Test Data                     5-9

5.3  Indications of the Need for a Revised Standard              5-11

     5.3.1  Particulate Matter Standard for Portland
            Cement Kilns                                         5-11
     5.3.2  Particulate Matter Standard for Portland
            Cement Clinker Coolers                               5-12
     5.3.3  Opacity Standards                                    5-12

6.0  ANALYSIS OF THE IMPACTS OF OTHER ISSUES ON NSPS             6-1

6.1  Industry Economics and New Construction                     6-1
6.2  Excessive Emissions During Cement Kiln Startup              6-14
6.3  Raw-Mill Bypass                                             6-15
6.4  Use of Alternate Fuels                                      6-16
6.5  Gaseous Emissions                                           6-17

     6.5.1  Carbon Monoxide                                      6-17
     6.5.2  Fluorine                                             6-17
     6.5.3  Hydrocarbons                                         6-17
     6.5.4  Hydrogen Sulfide                                     6-18
     6.5.5  Nitrogen Oxides                                      6-18
     6.5.6  Sulfur Oxides                                        6-19

7.0  FINDINGS AND RECOMMENDATIONS                                7-1

7.1  Findings                                                    7-1

     7.1.1  Process Emission Control Technology                  7-1
     7.1.2  Economic Considerations                              7-1
     7.1.3  Gaseous Emissions                                    7-2

7.2  Recommendations                                             7-2

     7.2.1  Opacity NSPS                                         7-2
     7.2.2  Particulate Matter NSPS                              7-2
     7.2.3  Gaseous Emissions                                    7-3

8.0  REFERENCES                                                  8-1
                                  vi

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                        LIST OF ILLUSTRATIONS

Figure Number                                                    Page

     4-1          Geographic Distribution of Portland
                  Cement Plants (November 1978)                   4-2

     4-2          Production of Portland Cement                   4-7

     4-3          Particle Size Distribution of  Cement Dust      4-16

     4-4          Resistivity of Dust from Portland Cement
                  Kilns and Coolers                              4-18

     4-5          Rexnord, Inc. Gravel Bed Filter                4-24

     5-1          Portland Cement Plants NSPS Compliance
                  Test Results Kiln Particulate  Matter
                  Emissions                                      5-5

     5-2          Portland Cement Plants NSPS Compliance
                  Test Results Clinker Cooler Particulate
                  Matter Emissions                               5-6

     6-1          Construction Spending and Cement Output        6-2

     6-2          U.S. Portland Cement Capacity  and
                  Production                                     6-3

     6-3          Cement Plant Clinker Capacity  by Age
                  of Kiln                                        6-5

     6-4          Cement Plant Kiln Age                          6-7
                                  vii

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                           LIST OF TABLES

Table Number                                                     Page

     4-1          Portland Cement Clinker Production
                  Capacity                                       4-3

     4-2          Energy Consumption of Portland Cement
                  Manufacturing Processes                        4-5

     4-3          Summary of Major Sources of Cement
                  Dust Emissions                                 4-11

     4-4          Typical Composition of Dried Kiln Dust         4-13

     4-5          Particle Size Distribution of Alkalies
                  in Kiln Dust                                   4-14

  ^  4-6          Ranges of Dust Emission from Control
                  Systems Serving NSPS Portland Cement Plants    4-27

  ^  5-1          NSPS Compliance Test Results for
                  Portland Cement Plants                         5-2

  t-  5-2          Results of Using Various Particulate
                  Matter Control Technologies at Portland
                  Cement Plants                                  5-8

     5-3          Analysis of Portland Cement Plant
                  Compliance Test Data                           5-10

     6-1          Portland Cement Clinker Production
                  Capacity                                       6-10

     6-2          Announced Cement/Clinker Capacity
                  Changes as of November 15, 1978                6-11
                                 viii

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1.0  EXECUTIVE SUMMARY




     The objective of this report is to review the New Source Per-




formance Standards (NSPS) for portland cement plants in terms of




developments in control technology, economics, and new issues that




have evolved since the original standard was promulgated in 1971.




Possible revisions to the standard are analyzed in the light of com-




pliance test data available for NSPS-affected facilities.  The review




includes the particulate matter mass emission limit for cement kilns




and clinker coolers, as well as the opacity standard for these and




other sources within the cement plant.  The following paragraphs sum-




marize the results and conclusions of the analysis, as well as recom-




mendations for future action.




1.1  Best Demonstrated Control Technology




     The portland cement industry was one of the first industries to




have a NSPS promulgated to control their emissions due to the large




quantity of particulate matter emitted.  The cement kiln and clinker




cooler are the primary sources of those emissions.  The original




standard was based on greater than 99 percent removal of particulate




matter from the exhaust streams of the kiln and cooler by fabric




filter baghouses.  Electrostatic precipitators (ESPs) used at that




time were incapable of meeting the new standard.  Since that time,




ESPs have been improved to the point where they also are capable of
*This report is based on data that were available in November 1978.





                                 1-1

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controlling emissions from cement kilns to satisfy NSPS requirements.

Gravel bed filters and one wet scrubber have been used successfully,

in addition to the baghouse, to control emissions from clinker

coolers.

     There are 49 NSPS affected cement kilns and clinker coolers

operating.  Data were available on 29 kilns and 20 coolers,  all of

which were in compliance.  Electrostatic precipitators were  installed

on 12 kilns, baghouses on 16 kilns and 16 coolers, gravel bed filters

on 3 coolers, and a wet scrubber was installed on 1 cooler (Data for

one kiln compliance test did not include the type of control.)

1.2  Current Particulate Matter Emission Levels Achievable with Best
     Demonstrated Control Technology

     Of the 49 known NSPS-affected cement kilns and clinker  coolers,

47 are in compliance with the 0.15 kg/Mg kiln feed (kiln) and 0.05

kg/Mg kiln feed (cooler) emission limits.  One completed kiln has

only recently been tested and data are not available; and one fa-

cility has notified its state authority that it cannot meet  the stan-

dard.  The number of sources with other NSPS-affected facilities is

unknown, although there are none that are not in compliance  with the

applicable 10 percent opacity standard.

     The mean emission rate for 29 cement kilns was 0.073 kg/Mg dry

kiln feed (range 0.013 to 0.142).  There was a random spread of test

results within the range of values,  indicating that no control or

process technology was consistently better at reducing emissions.
                                 1-2

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     The mean emission rate for 20 clinker coolers was 0.024 kg/Mg




dry kiln feed (range 0.005 to 0.061).  Again, there was no correla-




tion among control, process, and emission level.




     There are no data to indicate the effect of time on the emission




levels measured.  It can be assumed that emissions increase as con-




trol equipment deteriorates with age.




1.3  Economic Considerations Affecting the NSPS




     The cement industry has been thoroughly investigated by the




Council on Price and Wage Control because of its influence on the




construction industry.  Although the Council concluded that pollution




controls are not the most important factor in cement plant closings,




it did state that a large increase in pollution abatement costs could




influence new construction.  This is very important in a period when




regions of the U.S. are experiencing a shortage of cement production




capacity.




     Because of the maximum capabilities of the control technologies




and the closeness of many of the compliance tests to the standard, it




is recommended that the present level of emissions specified in the




current NSPS not be changed.




1.4  Future Additions to the Standard




     The portland cement industry generates large quantities of




gaseous pollutants, primarily NOX and S02.  The sulfur dioxide




emissions are reduced approximately 70 percent by sorption in the
                                1-3

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process and are incorporated in the clinker, or removed with the col-




lected dust.




     Nitrogen oxides, however, are emitted to the atmosphere with-




out control.  Using EPA NOX emission factors, it is estimated that




as much as 93,000 metric tons (Mg) of NOX were emitted by cement




plants in 1977.  Presently, there are no economically feasible con-




trols for these emissions.




     It is recommended that research be conducted to determine the




actual cement kiln 802 an<* N0x emission levels and that the effect




of process changes, such as flash calciners, on NOX generation be




determined.
                                1-4

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2.0  INTRODUCTION

     Section 111 of the Clean Air Act, "Standards of Performance

for New Stationary Sources," requires that "The Administrator shall,

at least every four years, review and, if appropriate, revise such

standards following the procedure required by this subsection for

promulgation of such standards."  Pursuant to this requirement, the

MITRE Corporation, under EPA Contract No. 68-02-2526, is to review

10 of the promulgated NSPS including portland cement plants.

     The purpose of this report is to review the current portland ce-

ment plant standards and to assess the need for revision on the basis

of developments that have occurred or are expected to occur in the

near future.  This report addresses the following issues:

     1.   Review of the definition of the present standard.

     2.   Review of the portland cement industry and the status of
         applicable control technology.

     3.   Analysis of the cement plant particulate matter emission
         test results and a review of the level of performance of
         best demonstrated control technology for emission control.

     4.   Review of the portland cement industry economics and pro-
         jections of new kiln construction.

     5.   Discussion of cement plant gaseous  emissions and control
         technology presently available.

     Based on the information contained in this report, a set of

findings is presented and specific recommendations are made for

changes  in the NSPS.  In addition, recommendations are made for R&D

studies  on gaseous emissions.*
 This report is based on data that were available in November 1978.

                                 2-1

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 3.0  CURRENT STANDARDS FOR PORTLAND CEMENT PLANTS




     In accordance with the Clean Air Act of 1973, New Source Per-




 formance Standards (NSPS) were promulgated that specified allowable




 levels of particulate matter emissions from portland cement plants.




Any portland cement plant which commenced construction on or after




August 17, 1971, became subject to the NSPS.




     The NSPS for portland cement plants were originally promulgated




on December 23, 1971.  On June 29, 1973, the U.S. Court of Appeals




 for the District of Columbia remanded the NSPS for portland cement




plants to the Environmental Protection Agency as a result of ques-




 tions regarding the standards, in particular opacity standards (40




CFR 60.60).  Petitioned by the Portland Cement Association with re-




spect to the opacity standards, the Court of Appeals identified two




aspects of the standards as bases for concern:  (1) the inherent




reliability of opacity standards, i.e. whether measurements of opac-




ity can be made with reasonable accuracy, and (2) the achievability




of the opacity standard set for portland cement plants.  EPA's re-




sponse to the remand concluded that the opacity standard is a reli-




able,  valid and necessary standard that meets the requirements of




Section 111 of the Clean Air Act, and that the standards other than




the opacity standard should not be changed (EPA,  1974).  However,




EPA did conclude that the opacity standard should be revised.  Where




the opacity standard had originally been 10 percent for all affected




facilities, it was subsequently modified on June 14, 1974, to 20
                                 3-1

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percent for cement kilns and 10 percent for all other affected fa-

cilities (EPA, 1974).  EPA's position was supported by the Court.

3.1  Affected Facilities

     The facilities of a portland cement plant that are subject to

NSPS are the:  kiln, clinker cooler, raw mill system, finish mill

system, raw mill dryer, raw material storage, clinker storage, fin-

ished product storage, conveyer transfer points, bagging, and bulk

loading and unloading systems.  Also affected by NSPS are modified

Portland cement plants (a plant that has undergone a physical or

operational change that increases the emission rate of any pollutant

regulated by the standard) and reconstructed portland cement plants

(those in which the cost of replacement components exceeds 50 percent

of the cost of building a comparable new facility).

3.2  Controlled Pollutants and Emission Levels

     The NSPS for portland cement plants require the control of par-

ticulate matter emissions.  As stated in 40 CFR 60.62, no owner or

operator of a portland cement plant under construction on or after

August 17, 1971, shall discharge or cause the discharge into the

atmosphere from any kiln any gases which:

     1.  Contain particulate matter in excess of 0.15 kg/Mg
         (0.30 Ib/ton) of feed to the kiln, or

     2.  Exhibit 20 percent opacity or greater;
                t
or discharge to the atmosphere from any clinker cooler any gases

wh i ch:

     1.  Contain particulate matter in excess of 0.050 kg/Mg
         (0.10 Ib/ton) of feed (dry basis) to the kiln, or
                                  3-2

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     2.  Exhibit 10 percent opacity or greater;

or discharge to the atmosphere from any affected facility other than

the kiln and clinker cooler any gases which exhibit 10 percent opac-

ity, or greater.

3.3  Testing and Monitoring Requirements

     A performance test of a portland cement plant must be conducted

within 60 days after the facility has achieved its maximum production

rate and not later than 180 days after its initial startup.  Such a

test consists of three separate runs of which the arithmetic mean is

the result for determining compliance with NSPS.  If one of the runs

is lost due to forced shutdown, failure of an irreplaceable portion

of the sample train, extreme meteorological condition, or other

circumstances beyond the operator's control, the arithmetic mean of

the remaining two runs may suffice as the performance test result,

upon approval by the Administrator.

     Test methods to be used to determine compliance with NSPS are:

     1.  Method 5 for the concentration of particulate matter and the
         associated moisture content, with minimum sampling times of
         1 hour and minimum volumes of 0.85 dscm (kiln) and 1.15
         dscm (cooler)

     2.  Method 1 for sample and velocity traverses

     3.  Method 2 for velocity and volumetric flow rate

     4.  Method 3 for gas analysis.

     The owner or operator of a portland cement plant subject to NSPS

is also required to record the daily production rates and kiln feed

rates.  •


                                 3-3

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3.4  Regulatory Basis for Any Waivers, Exemptions, or Other
     Tolerances

     Compliance with the mass emission standard is determined by the

results of performance tests (Reference Method 5).  These tests are

conducted only on an affected facility that is operating at a level

representing normal operations.  Operations during periods of start-

up, shutdown, and malfunction are specifically exempted as nonrepre-

sentative operations.

     The opacity standard applies at all times except during periods

of startup, shutdown, and malfunction.  Opacity readings of portions

of plumes that contain condensed, uncombined water vapor are not used

to determine compliance.  Although these exemptions apply to all

affected facilities, owners and operators are required to maintain

and operate their facilities in a manner consistent with good air

pollution control practice for minimizing emissions, even during the

exempt periods.
                                3-4

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4.0  STATUS OF CONTROL TECHNOLOGY




4.1  Scope of Portland Cement Operations




     4.1.1  Geographic Distribution




     There are currently 53 cement companies producing portland




cement in the U.S.  The largest producers are Ideal (6.5% of total




capacity), Lone Star (6.2%), Martin Marietta (5.1%), and General




(5.0%).  The 53 companies operate 158 cement plants throughout the




U.S. with the largest single plant having a total cement capacity




of 2,161,000 Mg per year.  The smallest plant has an annual cement




capacity of 50,000 Mg (Portland Cement Association, 1978).




     The industry also operates plants solely with clinker grinding




facilities.  These plants (eight in all with a total annual cement




capacity of 2,614,000 Mg) use either imported or domestic clinker as




feed material and are very important during periods of high demand




when imports increase to make up for a lack of domestic clinker




producing capacity.




     The geographic distribution of the cement plants is shown in




Figure 4-1.  Cement plants are found in nearly every state because




of the high cost of transportation.  The actual clinker capacity of




these plants is also distributed throughout the U.S., although some




regions have little capacity due to a lack of demand.  Table 4-1




shows the distribution of clinker production capacity in each EPA




Region.  The clinker capacity in New England, the Northwest, and




Midwest is dwarfed by the capacity of the rest of the country.







                                  4-1

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                           • Portland Mmmt piMt
                           • Grinding only ptanU
Rt +L QBOalUPHtC MSTMIUTION 0^ POATLANO CEMENT PUINTS

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                                                   TABLE 4-1
                                  PORTLAND CEMENT CLINKER PRODUCTION CAPACITY
to
EPA
Region
I
II
III
IV

V
VI




VII

VIII

IX

X
TOTAL

Clinker,
Capacity
(103 Mg/yr)
None
4,248
12,159
14,852

13,337
11,889




10,431

3,942

11,789

2,333
84,980

New
No.
None
1 Dry
3 Dry
7 Dry
4 Wet
9 Dry
2 Dry
3 Wet



4 Dry

1 Dry
3 Wet
2 Dry
1 Wet
None
29 Dry
11 Wet
Kilns 1972-19783
Capacity (103 Mg/yr)b

490
1,602
3,883
1,744
4,215
753
785



1,123

509
863
720
441
-
13,295
3,833

No.
None
None
None
1 Dry
1 Dryd
1 Dry
1 Dryd
2 Dry
1 Dryd
1 Dry
1 Dryd
1 Dry
1 Dry
1 Dry
1 Wet
3 Dry
3 Dry
1 Dryd
19 Dry
1 Wet
£
Announced Growth
Capacity (103 Mg/yr)

-
-
100
1,361
518
499
236
726
205
907
131
603
122
81
483
1,406
454
7,751
81

Yeara

-
-
79
81
80
79
79
80
80
NA
78
80
79
79
79
NA
79


         NA = Not Announced

         ^Completion Year
          As of December 31, 1977
         JjAs of November 15, 1978
          New plant

         Source:  Portland Cement Assn., 1978.

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Although many areas of the country are presently experiencing cement

shortages and delays, announced capacity increases in these areas are

still small.  Table 4-1 also shows the trend toward new construction

of dry process kilns.  During the last 7 years, nearly three times as

many dry process kilns as wet process kilns have been built (29 dry

vs. 11 wet), for an increase in clinker capacity of 17,128,000 Mg/yr

(13,295,000 dry vs. 3,833,000 wet).

     4.1.2  Technological Trends in Production

     The portland cement industry is very energy intensive with

energy costs accounting for approximately 40 percent of the cost of

cement.  A number of new innovations have been made in the production

process to increase energy efficiency.  The dry process can be twice

as energy efficient as the wet process.  The dry process uses driers

or combined drying/grinding units to reduce the raw material free

moisture content to less than 1 percent.  The wet process is very

similar to the dry process except that water is added to the raw

materials before or during grinding so that the kiln feed material is

a slurry.  Energy savings are realized immediately because there is

no water to evaporate from the feed material.  For this reason,

almost all new and planned construction will use the dry process.

Additional large savings can be realized by using preheatero, espe-

cially suspension preheaters.  Table 4-2 shows the energy savings

attributable to the various new technologies.

     These process changes have both positive and negative effects on

particulate emissions.  The replacement of wet process units with dry
                                 4-4

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                              TABLE 4-2

    ENERGY CONSUMPTION OF PORTLAND CEMENT MANUFACTURING PROCESSES
                                        Energy       Energy Reduction
                                      Consumption      Over Average
     Process                         (lO^ BTU/ton)  Current Practice (%)
Wet Process

  Long Kiln (average current practice)   5.94             	
  Calcinator and short kiln              4.68             26.9
  Preheater and short kiln               3.60             43.8
Dry Process
  Long Kiln (average current practice)   4.68             	
  Suspension preheater and short kiln    3.15             50.8
  Grate preheater and short kiln         3.42             46.6
SOURCE:  Ketels et al., 1976.
                                4-5

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process units increases emissions, particularly in the grinding, mix-

ing, blending, storage, and feeding of raw materials to the kiln.

The suspension preheater, on the other hand, tends to decrease

particulate emissions due to its multicyclone construction.  It also

ensures more thorough contact of the kiln exhaust gases with the feed

material which may increase sorption of sulfur oxide from the exhaust

on the feed.

4.2  Production of Portland Cement

     There are four distinctive steps in the production of portland

cement:

     •  Quarrying and crushing of raw materials

     •  Grinding and blending raw materials

     •  Clinker production

     •  Finish grinding and packaging.

These four steps are depicted in Figure 4-2.  The production of port-

land cement begins with the quarrying of raw materials.  In the

initial step, cement rock, limestone, clay, and shale are generally

mined from open pit quarries at or near the cement plant.  The large

rocks are crushed to a final size of 2 to 2.5 cm and stored for

future use in piles or compartments.

     The second production step is the preparation of raw materials

for feeding to the kiln (pronounced "kill").  The raw materials are

ground to approximately 200 mesh either before, during, or after

blending.  Either the dry process or the wet process is used.  In the

dry process, heat for drying is provided by direct dryer firing of
                                 4-6

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/\ ...«y_
                            QUARRYING AND CMMHUtO OPERATION
                                -^^..jni'i'iniiKij
                                                 i


                          —^   ^  iy'r—i—
                          iww«23/n  -'  '—'"*"*. •.
                                  U  TDMHIIOMpfP^-'
                        RAW MATERIALS ARE GROUND TO POWDER AND BLENDED
                            U-Sf-—*^


                           rrrrL-1 I
                           safeajir^ ^
                                                              /crrmTK
                                     Figure 4-2B


                              GRINDING WO BLENDING OPERATIONS
                                    FMUHE44C.

                                   KILN DURATION
                                                                  0
                                                                     Ml
 UA DMUIiMnl ol HtMh. Uuullon. and Wdlin. 1 Mr.



                           FINE aMNonra AND PACKAOINQ OPERATION


                       FIGURE «. PRODUCTION OF PORTLAND CEMENT
                                       4-7

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coal, oil or gas, separately fired furnaces, or hot kiln exhaust




gases.  The finished finely ground raw material is then conveyed to




blending, homogenizing, and/or storage silos.  Kiln feed is then




withdrawn from the silos.




     In the wet process, the raw materials may be proportioned prior




to grinding or individual raw material slurries may be blended after




grinding.  The finished slurry used as kiln feed may be 30 to 40




percent water or it may be dewatered to approximately 20 percent




water and fed as a filter cake.




     The third step, clinker production, is the heart of the opera-




tion.  Proper firing of the kiln will determine the quality of the




final product.  Cement kilns range in size from 60 feet in length and




6 feet in diameter to 760 feet in length and 25 feet in diameter.




The kiln is placed in a near-horizontal position with a slope of 0.03




to 0.06 cm/m of length and rotates on its longitudinal axis.  The




blended feed material (wet "slurry" or dry "raw meal") is fed into




the upper (highest) end of the kiln.  Firing is done from the lower




end of the kiln using coal, oil or gas fuel so that the exhaust gases




flow countercurrent to the feed material.  As the feed flows slowly




down the kiln, it is exposed to higher temperatures which first cause




heating, then drying, calcining, and sintering.  Finally, the feed is




heated to the point of fusion, resulting in clinker.  Clinker, a




round, marble-sized particle, is formed at approximately 1595°C.




This requires process temperatures of up to 1650° at the lower end of






                                  4-8

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the kiln.  The clinker is cooled in a clinker cooler and stored for




finish grinding and packaging.



     Older kilns use suspended chains in the drying zone to assist




in moving the feed material down the kiln and to increase heat




absorption from the exhaust gases.  Many new dry process kilns use




pre-heaters which increase energy efficiency and permit shorter kilns




since heating, drying, and even calcining of the feed material can be




accomplished prior to entering the kiln.  Two types of preheaters are




presently in use:  grate and suspension preheaters.  The grate pre-




heater uses a slow moving grate which kiln exhaust gases pass through




to dry and heat pelletized feed.  The pellets are formed by mixing




the raw feed material with 10 to 12 percent water and forming pellets




approximately 2.5 cm in diameter.  The hot pellets are then fed di-




rectly to the kiln.




     The suspension preheater uses a multistage eyelone/suspension




system to ensure direct contact of the kiln exhaust and the dry raw




meal feed.  The kiln exhaust gases flow counter-current to the raw




meal feed through a series of staged cyclones.  This system is used




on dry process units only.  (A state-of-the-art discussion of the re-




inforced suspension preheater (RSP) process can be found in




Kohanowski and Shy, 1978.)




     The final step of cement production is the finish grinding and




packaging.  Clinker is finely ground (approximately -325 mesh) in a




ball mill or tube mill in one or two stages.  Ground with the clinker






                                  4-9

-------
is a small amount of gypsum (4 to 6 percent) which controls the set-

ting time of the cement.  The portland cement is then stored, bagged,

or shipped in bulk by truck, rail, barge, or ship.

4.3  Particulate Matter Characterization

     Dust is generated throughout a cement plant with the largest

quantities coming from the kiln and clinker cooler.  Table 4-3 is

a summary of the major sources of particulate matter emissions at a

cement plant.  The dust from burning is a mixture of substances that

are nearly identical to the kiln feed with two exceptions:  (1) some

of the dust has been partially calcined, and (2) the dust has a high

alkaline content.  Partial calcination prevents recycling the dust to

the feed end of a wet process kiln, since it will harden on contact

with water.  This problem does not occur in dry process kilns.  In-

sufflation,, adding the dust at the burner, is also used to recycle

the dust if the alkalinity is not excessive.  Insufflation can be

used in either wet or dry process kilns.

     Most kiln dust is too alkaline for recycling, however, and must

be either leached with water prior to recycling (generally wet pro-

cess) or disposed of, usually into settling ponds or landfills*

These disposal practices lead to fugitive air emissions during trans-

port and water pollution from leachate.

     The reasons that make waste kiln dust unacceptable for recycling

in the kiln also make it a potential resource (although this poten-

tial is inhibited due to the heavy metal content).  The characteris-

tics of kiln dust that make it potentially useful as a resource are
                                4-10

-------
                          TABLE 4-3

                  SUMMARY OF MAJOR SOURCES
                  OF CEMENT DUST EMISSIONS
Process
Burning
(kiln)

Clinker Cooler



Finish Grinding
(mill)

Bagging
Emission Dust
Concentration Mean Size
(g/m3) (nm)
100 - 400 20a
(83.5 g/kg (7 - 40)
of cement)
50 50



25 - 1000 30
(15 - 40)

10 - 40 30
Specific
Gravity Control
(g/cm3)
2.3 - 2.9 ESP (wet)
Fabric
Filter (dry)
ESP or bag-
house pre-
ceded by
cyclone
2.7 - 3,1 Fabric fil-
ter preceded
by separator
Bag filters
 After control by ESP, the mean size emitted to the atmosphere is
 about 1
Source:  Davis and Hooks, 1975.
                             4-11

-------
its potassium and lime content, acid-neutralizing capacity, and abil-




ity to harden upon hydration.  The dust can be used as a fertilizer




or soil conditioning agent.  It can neutralize acid soils and sweeten




acidic lakes, bogs, or acid mine drainage.  There are numerous other




potential uses for kiln dust ranging from use as a water treatment




flocculating agent to a source of potash.




     The composition of kiln dust varies as widely as the feed mater-




ial and the firing process used.  Depending on chemical compound




volatilities and vapor pressures, varying quantities of these com-




pounds will end up in the kiln dust rather than in the clinker.  A




typical elemental composition of dried kiln dust is shown in Table




4-4.  As expected, carbonate from uncalcined limestone, potassium,




sodium, and calcium are the major components of kiln dust.




     Under the oxidizing conditions in the high temperature clinker




forming zone of the rotary kiln numerous oxides will form.  Due to




their high vapor pressure, some of these will volatilize and travel




to the cooler portions of the kiln with the kiln exhaust.  Upon cool-




ing, these oxides will condense as a fume.  The very small fume




particles will exit with the kiln exhaust and be captured in the




baghouse or electrostatic precipitator.  Because of their very small




size, the alkaline salts which form a fume will be precipitated in




the last chambers of a precipitator, but will be dispersed throughout




a baghouse.  Table 4-5 shows an analysis of the distribution of alka-




lies from a kiln dust electrostatic precipitator based on particle





                                 4-12

-------
                              TABLE 4-4

                       TYPICAL COMPOSITION OF
                           DRIED KILN DUST
   Component
                                                          Weight %
Clay (HC1 insoluble, fired at 800°C)
Organic substance

Cations
                                                            4.61
                                                            2.06
Lithium
Sodium
Potassium
Rubidium
Cesium
Magnesium
Calcium
Strontium
            K
            Kb]
            Cs
            Mg
            Ca
            Sr
                                                0.0064
                                               12.25
                                               24.50
                                                0.475
                                                0.0074
                                                Trace
                                                9.26
                                                0.015
Anions

Fluoride
Chloride
Bromide
Iodide
Carbonate
Sulfate
Sulfide
Borate
Phosphate
F
Cl"
Br"
I "
CO.
SO
S
BO
4__
                                                            0.46
                                                            1.43
                                                            0.040
                                                            0.0552
                                                           29.59
                                                            9.06
                                                            Trace
                                                            0.152
                                                       Not detectable
     Heavy Metals (Weight %)
                                       Heavy Metal Oxides  (Weight %)
Chromium Cr 0.011 Cr203
Manganese Mn 0.013 Mn02
Iron Fe 0.84 Fe2C*3
Zinc Zn 1.62 ZnO
Lead Pb 0.562 PbO
Sum of all determinations
Oxygen (from CaO not bound in carbonate)
Sum of all constituents
0.016
0.021
1.19
2.02
0.607
97.825
2.98
100.805
Source:  Davis and Hooks, 1975.
                                  4-13

-------
                             TABLE 4-5

                    PARTICLE SIZE DISTRIBUTION
                     OF ALKALIES IN KILN DUST
Particle
Size
Range (urn)
>68
<68>48
<48>34
<34>24
<24>17
<17>12
<12>6
<6
Weight
Total Alkalies
(Percent)
(Percent) ys o v n
0
0.3
0.4
0.7
1.8
5.1
27.3
64.4
—
0.30
0.31
0.35
0.38
0.40
0.33
0.42
—
3.62
3.46
4.51
5.08
5.15
5.35
10.72
Water Soluble
Alkalies (percent)
Na20
—
a
a
0.094
0.117
0.134
0.134
0.242
K20
—
a
a
1.927
2.560
3.072
3.252
8.191
 Insufficient sample for analysis.
Source:   Davis and Hooks, 1975
                                4-14

-------
size. Over half (64.4 percent) of the alkali particles are less than




6 microns in diameter.  As shown in Table 4-4, the alkalies (potas-




sium, sodium, rubidium, etc.) form most of the kiln dust.  From these




analyses, one would expect the majority of kiln dust to be made up of




very small particles.




     Over half the particles in cement kiln dust are, in fact, less




than 10 microns in diameter.  This varies by process and feed mate-




rial, but a particle size distribution curve showing ranges of par-




ticle sizes can be drawn (Figure 4-3).  This figure also shows the




particle distribution for clinker cooler dust.




     Figure 4-3 shows the differences in the particle size distri-




bution of cement dust from a preheater kiln, wet process kiln, and




clinker grate cooler.  In this presentation it is obvious that the




particles are smallest from a preheater kiln and largest from a




clinker grate cooler.  This is probably due to the multicyclone con-




figuration of the preheater which will capture the larger particles




and return them to the kiln.  Although data are not available, one




would expect that the dust from the preheater kiln would be very high




in alkaline salts, especially with 15 to 40 percent of the particles




less than 1 micron in diameter.




     Another characteristic of the kiln dust that is of importance to




the control of emissions is resistivity.  The resistivity of the dust




is a factor indicating the ease of applying a negative charge to a
                                 4-15

-------
       Preheater Kiln
             2  345
Source:  Lind, 1978.
10
20 30  50   100  200
500
                     FIGURE  4-3
     PARTICLE SIZE DISTRIBUTION OF CEMENT DUST
                        4-16

-------
particle and determines the effectiveness of an electrostatic precip-

itator.  From the dust resistivity data shown in Figure 4-4, it is

apparent why ESPs are not used to control the particulate emissions

from clinker grate coolers.  On the other hand, the emissions from a

wet process rotary kiln are particularly suitable for control by an

ESP due to their low resistivity.  Figure 4-4 also shows the effect

of temperature on dust resistivity.  Resistivity increases with

temperature up to 200° to 250°C, above which it decreases as the

temperature continues to rise.

4.4  Control Technology Applicable to the NSPS for Portland Cement
     Plants

     Particulate matter emissions from portland cement plants are

generally controlled with dry mechanical collectors of three types:

cyclones, ESPs and fabric filters.  However, in some cases, gravel

bed filters and wet scrubbers are used.  In most instances, the cy-

clones are used in conjunction with either a precipitator or fabric

filter.  Although the NSPS was based on the use of a fabric filter

baghouse, other control technologies are capable of reducing emis-

sions to meet the NSPS.  These control technologies will be discussed

individually in the following sections.

     4.4.1  Cyclones

     Cyclones are the most basic and elementary of the three types

of particulate matter collectors.  They are the least expensive,

easiest to maintain, and have the lowest pressure drop, but are the

least efficient.  If an emission source is to meet the stringent air

                                4-17

-------
     Qcm
          Clinker Grate Cooler
                                          'Alkali By-Pass
4 Stage
Preheater
Kiln
          1 Stage
          Preheater
          Kiln
          Long Dry Kiln
          Wet Kiln
                   100

     Source:  Lind, 1978.
                     200
300
400 °C
                          FIGURE  4-4
RESISTIVITY OF DUST FROM PORTLAND CEMENT KILNS AND COOLERS
                              4-18

-------
pollution standards, a cyclone must be followed by either an ESP or




a fabric filter*  Collection efficiencies of a cyclone are 60 to 80




percent depending on the particle size.  The efficiency begins to




drop off when the particles reach the range of 20 to 40 microns in




diameter (Research Triangle Institute, 1970).  Since over half the




cement dust is less than 10 microns in diameter, the cyclone cannot




reduce emissions sufficiently to meet the NSPS.  Used in conjunction




with an ESP or fabric filter, however, removal efficiencies greater




than 99 percent are achievable while reducing the abrasion caused by




larger particles.




     4.4.2  Electrostatic Precipitators




     Electrostatic precipitators operate by maintaining a corona




discharge between a negatively charged electrode and a grounding




plate.  The exhaust gas stream passes through the corona discharge,




and entrained particles pick up a charge.  The charged particles




are attracted to the grounding plates where they agglomerate.  The




cleaned gas stream continues on to the stack, while the agglomerated




particles are removed from the plates by frequent "rapping" and fall




into dust hoppers for future removal and disposal.




     A number of variables influence the efficiency of an ESP:  gas




velocity, moisture content and temperature, and dust quantity, parti-




cle size, resistivity and physical characteristics.  Although all of




these variables are important to the designer, dust particle resisti-




vity is the most important.  Particles with a high resistivity will






                                4-19

-------
not acquire a charge when they pass through the corona discharge.

Kiln dust from a preheater kiln has a resistivity which makes an ESP

unsuitable.  The resistivity can be reduced, however, by treating the

exhaust gas prior to its entry into the ESP.  Moisture control is the

easiest method of pretreatment.  As the moisture content of the dust

is raised, the resistivity is reduced.  This is a primary reason for

the reduced resistivity of dust from a wet process kiln.

     Chemical exhaust gas conditioning is growing in use.  Polar

compounds adsorbed on the surface of particles can reduce resistiv-

ity and increase the ESP collection efficiency.  This has been dem-

onstrated as a viable method of reducing particulate emissions from

power plants converting to coal fuel.  Chemical conditioning has the

advantages of rapid installation (4 to 6 weeks) and cost (capital:

10 to 25 cents/kW capacity, and operation:  0.2 mil/kWh) (Chemical &

Engineering News, 1978).

     The advantages of an ESP are:

     1.  The ability to handle large volumes of gas with very little
         pressure drop.

     2.  Relatively lower power requirements (compared to fabric fil-
         ters) due to the low pressure drop.

     3.  The ability to handle high temperature gases and corrosives.

These advantages must be weighed against the disadvantages of using

an electrostatic precipitator at a  cement plant:

     1.  The entire ESP must be shut down and bypassed for mainte-
         nance or repairs when required.
                                 4-20

-------
      2.   Sulfur oxides  in  the exhaust gas corrode  the metal  parts
          causing reduced efficiency.

      3.   Sulfur acids can  diffuse into concrete casings and  eventu-
          ally destroy them.

      4.   Alkalies can coat high-voltage components and cause short
          circuits.

      Also, an ESP must  be bypassed during startup due to a fire and

explosion hazard from unburned fuel in a chamber with electrical

arcing.

      4.4.3  Fabric Filters

      Fabric filters are one of the oldest methods of removing dust

from  a gas stream.  The cement industry uses glass fiber filters

because they are reliable, efficient in removing particles in the

size  range of concern, and capable of withstanding high tempera-

tures.  Fabric filters are capable of greater than 99.5 percent

removal of cement dust from cement plant exhaust streams.

     The  advantages of fabric filters are:

      1.  Reliability

      2.  Lower cost due to simplicity

      3.  Very high removal efficiencies

     4.  Rapid repairs and the opportunity to isolate areas for
         repair and maintenance without bypassing the entire
         bag-house.

Baghouses have disadvantages also:

      1.  Increased pressure drop (relative to ESP) which must be
         overcome by induced draft.

     2.  Increased cost of draft equipment may overcome the other
         cost advantages.
                                4-21

-------
     3.  Susceptibility to clogging from moisture.

     4.  Bag-life is very dependent on temperatures and is limited
         to less than 315°C (600°F).

     In general, it appears that the glass-fabric baghouse would be

used for collecting particulate matter from the dry-process kiln and

clinker cooler gases and electrostatic precipitators would be the

choice for wet-process kilns.  However, it has been reported that a

higher collection efficiency can be maintained with the baghouse than

the precipitators (Research Triangle Institute, 1970) and, in fact,

the baghouse is used on both wet and dry process kilns.

     A survey of NSPS affected facilities shows 12 kilns with precip-

itators and 16 with baghouses.  Eighteen out of 22 clinker coolers

at these NSPS sites use baghouses to control particulate emissions.

Additional details on this data are discussed in Section 4.5.

     4.4.4  Gravel Bed Filters

     Gravel bed filters have been in use since 1957, primarily in

Europe.  Recently they have been used for particulate matter control

in the domestic cement industry.  In the period 1972-1978, Rexnord,

Inc., installed 24 gravel bed filters on domestic clinker coolers.

The available data show only two of these on sources subject to

NSPS—National Cement Company, Ragland, Alabama; and U.S. Steel,

Leeds, Alabama.  The compliance test results show both these units

as in compliance with 74 percent and 91 percent of allowable emis-

sions, respectively.
                                 4-22

-------
     Figure 4-5 shows a cutaway drawing of a Rexnord, Inc. gravel bed




filter.  The particle-laden gases from a clinker cooler or kiln




preheater enter the module at the raw gas inlet (A) and enter the




cyclone.  The cyclone (B) removes the larger particles and the gas




stream moves up the vortex tube (C) and into the raw gas chamber (D),




while the large dust particles are removed through a double tipping



gate (E) at the bottom of the cyclone.  The raw gas is directed




through the filter medium (F) where the remaining dust is removed.




The gas stream passes through the media support screen (G), into the




clean gas chamber (H), and out of the module through the clean gas




outlet duct (I).  When the filter media becomes clogged, the module




is backflushed by opening the backflush control valve (J) and forcing



clean air through the backflush duct (R).  This air passes up through




the tilter medium (F), while stirring rakers (L) agitate the medium.




The dust, which had been trapped in the filter medium, is removed and




directed back down the vortex tube (C) and either out the double tip-




ping gate or out the raw gas intake and to another module's cyclone.




Only one module is backflushed at a time so that particulate matter



control is in operation at all times.




     Advantages of the gravel bed filter, as reported by Shumway et




al. (1978), include:




     1.  Rapid construction (approximately 4 months)




     2. . Low maintenance costs (average $2,000/year)




     3.  Handling of increased gas flow during upset conditions






                               4-23

-------
    Raw Gas Dust
0
MM Primary Collector (Cyclone)

Ccj Vortex Tube

flO Raw Gaa Chamber

  M Double Tipping Gate (Dust Discharge)
    Gravel  Bed Filter Medium

Source:   Shumvay et al. , 1978.
   Screen Support  for Bed

 M Clean Gas Chamber

   Exhaust Fort

   Backf lush Control Valve

   Backflush Duct


LJ Stirring Raker
                                   FIGURE 4-S
                        REXNORD, INC. GRAVEL BED FILTER
                                      4-24

-------
     4.  Continuous particulate matter control during periods of
         maintenance or repair

     5.  Handling of high temperature gases (>371°C (>700°F) at
         Missouri Portland, Joppa, Illinois).

     4.4.5  Wet Scrubbers
     Wet scrubbers are not used very much in the portland cement

industry.  Only one unit is in operation on a NSPS-affected facility

(clinker cooler).  The principle of operation of a wet scrubber is

simply to trap a small dust particle in or on a larger water droplet

and then remove the droplet in a cyclone.

     Wet scrubbers are used in areas where elevated gas temperatures,

or sticky or hygroscopic dust is encountered.  They are also suitable

in areas where there is a preference for collected dust in a slurry

form.  They are not suitable for dust particles of submicron diame-

ter, dust which becomes corrosive when wet, or when there is a pre-

ference for collected dust in a dry form.

     These attributes and shortcomings make wet scrubbers suitable

for particulate matter control on clay dryers and in primary

crushing, screening and secondary rock crushing.  In each of these

situations, there may be sufficient moisture in the gas stream to

cause condensation problems in dry collectors.

4.5  Comparison of Levels Achievable with Best Demonstrated Control
     Technology Under the Present NSPS

     The available data on control technologies for the removal of

particulate matter from exhuast gas streams at portland cement plants

show that a number of controls are suitable for reducing emissions
                                4-25

-------
below the level required by the NSPS.  The technologies are described




in Section 4.4.  Table 4-6 summarizes the ranges of emissions from




control systems in use on NSPS-affected facilities.  Since the NSPS




for portland cement plants do not specify a mass emission limit for




sources other than kilns and clinker coolers, there are no data to




show the effectiveness of controls used for fugitive emissions or




emissions from grinding, drying, blending, packaging, etc., opera-




tions.




     As discussed in Section 4.4, there is no single best demon-




strated control technology for particulate matter emissions from




Portland cement plants.  Rather, there are four technologies that




are preferable under different circumstances within a plant and at




different plants.  Most portland cement plants use some combination




of cyclone, ESP, baghouse, and gravel filter to reduce the emission




of particulate matter.
                                4-26

-------
                              TABLE 4-6

        RANGES OF DUST EMISSION FROM CONTROL SYSTEMS SERVING
                     NSPS PORTLAND CEMENT PLANTS
                                             Range of Dust Emissions
                          Type of                From Collector
   Source	Dust Collector	(kg/Mg)a	

Kiln - dry             ESP                         0.021-0.125
                       Baghouse                    0.013-0.124
                       Gravel Bed                      NAb

Kiln - wet             ESP                         0.020-0.142
                       Baghouse                    0.049-0.132
                       Gravel Bed                      NA

Clinker Cooler         ESP                             NA
                       Baghouse                    0.005-0.061
                       Gravel Bed                  0.023-0.045
                       Wet Scrubber                0.022-c
aKilograms of particulate matter per metric ton of kiln feed.
^NA « No compliance test data.
cSingle compliance test result.

Source:  MITRE Corporation, 1978.
                                4-27

-------
5.0  INDICATIONS FROM NSPS COMPLIANCE TEST RESULTS




5.1  Test Coverage in the EPA Regions




     The Metrek Division of the MITRE Corporation conducted a survey




of all 10 EPA Regional Offices to gather available NSPS compliance




test data for each of the 10 industries under review (Watson et al.,




1978).  This survey yielded test data on 28 new portland cement




kilns/clinker coolers.  The data included average particulate mat-




ter emissions and opacity measurements for these units.  Only a few




opacity readings were reported, as compared with the total number of




tests.




     Information received from the Portland Cement Association in-




dicated that numerous additional NSPS-affected facilities existed.




Telephone contacts with EPA Regional personnel, State Air Pollution




Control Agencies, and, in some cases, with portland cement plant




operators yielded NSPS compliance test data on an additional 21




facilities.  Data were not obtained for seven other possible NSPS




cement kilns.  According to industry reports, this information




represents all of the portland cement plants completed from 1971




through 1978, and subject to the NSPS (MITRE Corporation, 1978).




5.2  Analysis of the NSPS Test Results




     The results of the NSPS compliance tests for 49 portland cement




NSPS-affected facilities are tabulated in Table 5-1 and displayed




in Figures 5-1 (cement kilns) and 5-2 (clinker coolers).  Only one




cement kiln subject to the NSPS is unable to pass a NSPS compliance
                                5-1

-------
                       TABLE 3-1




HSPS CCHFLUNCE TEST USOLTS FOK fOKTLAKD CEMENT PUHTS









f ••
Wl
1
ro















Plant Kilo
ueitm I
Menu n
Pllntkot* Caanaay 1
Claoa Palla Portland
Dlv. . Clan Palla. M.T.
Ban Joan Caawnt 3
Dorado. P.B.
Cop lay. Batarath. Pa. 1
Una Sear, Cltadal Ca-
•ant Corp.. Boaaoka, Va. 5

Hhltahall 3
Cananron, Pa.
BBCIOI IV
Cltadal faaanr Corp. 1
DaaopoUi, Ala.
Rational CaMnt Co. 1
Bag land, Ala.
Onlvaraal Atlaa Caaant 1
DU. of D.B. Btaal Coxy.
Laada, Ala.
Florida Mining t Hatarlala
Brookarllla. Via. 1
HlM} 10 IttafaUtTaLtM • IlfcCa 3
Tfluf»Mt^t yi«j.
Milan ran ant Co. 1
Cllnehflald. Ca.
Pllntkota 1
Taxaa Indoatrtaa 1
Artaala, Mlai.
Taar
Coapl'd

1973


1976

1978

1976

1973

1977
1976

1976



1973
197S
1974

1974
1974

Coapllane* Ta*t Data
rfflmj TrVr'lT Kll° Cllnkar Coolar
Capacity Pra- Kiln Cllnkar Fart Opacity Part Opacity
(Kg/day) haatar Procaaa Fual Coolar (kg/Mg) (I) (kg/Hg) (1)

1484£0.' X Dry Oil BBP Bag 0 :>"> 0.021 0 .' ---.i 0.017 1C
(0.088)

113*4), J Hat Oil Bag Bag 0.0 1C

2819 ; ' > X Dry Coal -- 1C

1*88 t!( J- X Dry Coal Bag „ 0)1, 0.013 0

619?^* X Dry Coal Bag 0,11$ 0.089 0-20

2132 T; Y X Dry Coal
1996 'r/. 7 X Dry Coal/ SSP Oraval f.il 0.035 <10 0.0~> 0.035 <10
Oil Bad
1619 7.iAV 0.062 3 0.10 0.45 5
Bad


1342 '" S X Dry Coal Bag Bag „ at(, 0.033 1C JO-'O 0.015 1C
1930 81 <• Hat Oaa ESP Bag 0 owi 0.01 1C O. o~"> 0.0)3 1C
1304 bl , 1 x Dry Coal Bag Bag ,] ivf 0.104 1C a . ^^0.028 ic

1733 50 fa X Dry Coal EBP Bag <,.( 0^0.031 1C 0 . *"/ 0.039 1C
103*^'. i/ Hat Caa BBP Hat g 1 '^ 0.103 1C 
-------
                                                                                     TABU 5-1 (Continued)
                                                                      «srs coiruMCB HST USULTS FOB NBTLMD CBMZMT nans
Cn



Plant
Glut Portland Coaant
Barlayrllla. S.C.
Clfford-Hlll Camant
Barlayvllla, S.C.
Santaa Portland Canant
Belly Rill. S.C.
n|ffini v
Mlaaourl Portland
Joppa. 111.
Cantax
LaSalla. 111.

Loalavllla CaMnt
Spaad. Ind.
Rational Gypaiai
Alpana, Mich.

Sontbwaatarn Portland
CaMnt, Falrborn, Ohio
Uhlgh, Hltchall, Ind.

Cantax, Auatln Canvnt
Co., Buda, Tax.
Clfford-Blll Caawnt
Midlothian, Tax.
Kalaar, San Antonio, Tax
OKC, Raw Orlaana, U.



Kiln
4

1

2


2

1


1
2
22

23

2
3

1

3

. 4
2


Taar
COBBl'd
1974

1974

1974


1975

1974


1973
1977
1975

1975

1974
1976

1978

1972

1975
1974


Capacity Pra-
(Mg/day) haatar
S90;7,0.3

1488

1665 7foV x
653 $O.O x

1500 lf& f

753 W. *

1052 40. ? X
880 <-fO- •/



Procaaa
Hat

Dry

Hat


Dry

Dry


Dry
Dry
Dry

Dry

Dry
Dry

Dry

Hat

Dry
Hat

Control Taehaoloiy
Kiln Cllnkar
Pual Coolar
Gai Bag Bag

Caa Bag Bag

Caa ESP Bag


Coal ESP

Coal


Coal
Coal GBO'1
Coal Bag

Coal **B

Coal Bag Bag
Coal

Bag Bag

Coal/ ESP
Caa
Coal Bag Bag
Coal Bag
CoBBlUnea Taat Data
Kiln Cllnkar Coolar
Part Opacity Part Opacity
(kg/Mg) (I) (kg/Mg) (I) R«arka
0 ivb 0.123 5 0.08C 0.043 5
,
. IOL/ 0.052 20 &.6 0.017 1C
'
j v v-S 0.129 1C 0' 0~> ° 0.035 1C


Q.tOO o.OSO 1C

Quaetlonabla atatua aa naw
aource.

.. .. ..
a. j-ru 8: Oil" 1C O. "VM).023 1C Two eonpllanea taata on kiln with
o.t'" avaraga of 0.1 kg/Mg.
Both kllna vantad to ciaainu
0 IfO 0.070 0 -- — baghouaa & itack. Stata taat
dona on atack In kg/Mg product.

O.t^le 0.123 0 fl.O"/ 0.007 0
Out of coaellanca. Mo taat
data tubalttad.
0.0(rb 0.033 Ic 5,31^0.012 Ic

0,iO 5"4 0.028 Ic

fl-dV 0.017 1C •> CIO 0.005 1C
0. 0$& 0.049 1C — — Taatad In coBpllanca, latar found
                                                                                                                                                  out of coaplUnc* & r«tMt»d.
                                                                                                                                                  frvccntly  In

-------
                                                                                    TaBU 5-1  (Concluded)
                                                                     mn cofPUMct TUT utian FOB NKTUJD cwnrr rum
o»

Plant
tMSKM Til
aah Crave Cenant Co.
LoulavlUe, Bob.
Borthmatern Sutaa
Haaon City. lora
Monmrch Cement Co.
HoBboUt. ba.
Vim TIT1
Utah Portland CaBent Co.
Bait Lake City. Utah
Meal, Portland, Col.
Uaal. Trident. Mont.
Soeth Dakota fanenf
Bapld City, S.D.
MBK1 H
Monolith Portland
Monolith. Cal.
mmaat »

Kiln
4

3

3

*

3
1
4

1

Tear
COBBl'd
1973

1976

1973

1973

1974
1973
1977

197*

Capacity Pre-
(Hg/day) heater Proceaa
1170 5 i .? x Dry

771 ^V Dry

'« 1^ I Dry

43* J ".1 Hat

1270 i * ^ Het
S34 ~'«.3 n,t
1342 ?"•/ x Dry

1315 ^'U Het

Blln Clinker Cooler
Kiln Clinker Part Opacity Pert Opacity
Puel Cooler (kg/*.) (V (kgTMg) (t) Unark.
Coal/ BBP Bag i7 . , ', ' 0.123 3-15 0 /:/O.Ml 5-10
CM
Coal Bag Bag <;"''- °-073 1C <^ ° - 0.011 1C

CM Bag Bag <9 > '•'- 0.123 5 ;.\ £' ^0.009 0

Coal/011/ Blgh efficiency cyclone -- — — _
CM follomd by baghouao BO til. at Beglon
Coal DP Bag r.'v"' °-077 M r "^ 0.014
Coal IBP o -Ll
-------
      Current NSPS
U.1J
? 0.13

-------
"O
0)

-------
test—Lehigh Cement, Mitchell, Indiana—and the company has not sub-




mitted to state air pollution officials any test data to indicate how




much their emission level exceeds the NSPS limit.  All clinker cool-




ers and other affected facilities are reported to be in compliance.




     5.2.1  Control Technology Used to Achieve Compliance




     Data received show that all 29 cement kilns and 20 clinker




coolers are in compliance with the NSPS.  Of the remaining 7 NSPS-




affacted cement kilns, five are known to be in compliance, one is




known to be out of compliance, and one has just recently been tested




and the results have not yet been analyzed.




     The particulate matter emissions from the portland cement plants




are controlled by ESPs, fabric filter baghouses, gravel bed filters,




and wet scrubbers.  Table 5-2 summarizes results of using these dif-




ferent control technologies on cement plant exhaust streams.




     Cement kilns have been tested at emission levels ranging from a




high of 0.142 kg/Mg feed and a low of 0.013 kg/Mg feed.  The range




for kilns with emissions controlled by ESP is 0.142 to 0.020 kg/Mg,




and for kilns with fabric filter baghouses the range is 0.132 to




0.013 kg/Mg dry kiln feed.  The data indicate that neither the ESP




nor the baghouse is significantly better at controlling cement kiln




particulate matter emissions.




     Cement plant clinker coolers have been tested at emission levels




ranging from a high of 0.061 kg/Mg and a low of 0.005 kg/Mg dry kiln
                                  5-7

-------
Ul
oo
                                                 TABLE 5-2

                                 RESULTS OF USING VARIOUS PARTICULATE MATTER
                               CONTROL TECHNOLOGIES AT PORTLAND CEMENT PLANTS
Electrostatic
Affected Facility Precipitator
Kiln Emissions (kg/Mg feed)
//Units
Maximum
Minimum
Clinker Cooler Emissions (kg/Mg feed)
#Units
Maximum
Minimum

12a
0.142
0.020

0

— —
Fabric Filter Gravel Bed
Baghouse Filter

16a
0.132
0.013

16a
0.043b
0.005

0
—
—

3a
0.045
0.023
Wet
Scrubber

0
—
—

la
0.022
0.022
       fNumber of units with available test data.
        A single compliance test shows 0.061 kg/Mg.  The EPA Region states that the source is in
        compliance
       Source:  MITRE Corporation, 1978.

-------
feed (mean 0.024 kg/Mg).  Compliance test data on a single wet scrub-

ber show emissions near the mean emission level for fabric filter

baghouse controls (0.022 kg/Mg).  Data for affected facilities using

gravel bed filters indicate a mean emission level of 0.034 kg/Mg dry

feed (0.023-0.045 kg/Mg).

     5.2.2  Analysis of Compliance Test Data

     The compliance test data shown in Table 5-1 were analyzed to

determine if any of the following variables affected the ability to

control the emission of particulate matter from portland cement kilns

or clinker coolers:

     •  Kiln control technology - ESP or baghouse

     •  Kiln control technology as a function of production process -
        wet or dry

     •  Kiln production process - wet or dry

     •  Clinker cooler control technology - baghouse, gravel bed
        filter, or wet scrubber.

     The results of this analysis are summarized in Table 5-3.  The

compliance test data were grouped into sets corresponding to the

previously mentioned variables, which facilitate comparisons of the

effectiveness of any single control technology, if a control was more

effective on a particular process, or if the effect of available con-

trols was more pronounced on a specific process.  The table shows the

number of compliance tests, the range and the mean of the test re-

sults, and the standard deviation and standard error of each set of

data.
                                5-9

-------
                                              TABLE 5-3           ;
                                                                            \
                        ANALYSIS OF PORTLAND CEMENT PLANT COMPLIANCE TEST DATA
Statistic '
Variable
Dry Process
ESP
Baghouse
Wet Process
ESP
Baghouse
All Processes
ESP
Baghouse
All Controls
Dry Process
Wet Process
All Kiln Data
Clinker Cooler
Baghouse
Gravel Bed
Wet Scrubber
All Controls

Number
Values*

8
10

6
4

14
14

18
10
28

16
3
1
20

Mlnlaumb

0.021
0.013

0.020
0.049

0.020
0.013
.
0.013
0.020
0.013

0.005
0.023
0.022
0.005

Maximum1*

0.125
0.123

0.142
0.132

0.142
0.132

0.125
0.142
0.142

0.061C
0.045
0.022
0.061

Mean

0.061
0.070

0.084
0.091

0.070
0.076

0.066
0.087
0.073

0.022
0.034
0.024

Standard
Error

0.012
0.013

0.021
0.021

0.011
0.011

0.009
0.014
0.008

0.004
0.006
0.003

Standard
Deviation NSPS

0.033 0.15
0.041

0.051
0.043

0.041
0.041

0.037
0.046
0.040

0.016 0.05
0.011
0.015
\
aNumber of compliance tests.
 Particulate emissions in kg/Mg feed.
CA single compliance test shows 0.061 kg/Mg.  The EPA Region
 states that the source is  in compliance.
Source:  MITRE Corporation, 1978.
                                                ^  *  Fx /r
                                             5-10

-------
     A comparison of the mean values for each set of compliance test

data indicates that no control technology in use today is more

effective for controlling particulate matter emissions.  The mean

values also indicate that there is a possibility that emissions from

dry process kilns are controlled slightly more effectively than wet

process kilns.  Further analysis shows that this is not, in fact, a

statistically significant difference.  The standard deviation, a

measure of the variability of the test results, indicates that the

current NSPS is set at a level that ensures continuous compliance

with an adequate margin of safety.

5.3  Indications of the Need for a Revised Standard

     5.3.1  Particulate Matter Standard for Portland Cement Kilns

     There is not sufficient justification for revision of the pre-

sent standard for cement kilns based on the following considerations:

     •  The current best demonstrated control technology is either
        fabric filter or ESP.  However, the original background study
        used fabric filter technology as the basis for the standard.
        This technology has not changed during the past 8 years.
        Although the ESP has improved, test results ate that it is
        not capable of significantly better performance than fabric
        filters.

     •  Although the mean emission rate for the 28 compliance tests
        analyzed was 0.073 kg/Mg dry kiln feed, the range was from
        0.142 to 0.013 kg/Mg dry kiln feed with 16 kilns tested above
        and 13 below the mean.  There was a random spread of test
        results throughout the range of values, indicating that there
        is no control or process technology that is consistently bet-
        ter at reducing emissions or having emissions reduced.

     •  Although no data are available, it is generally accepted
        knowledge that control technologies being used at cement
        plants deteriorate with age.  Baghouses, ESPs, and cyclones
                                5-11

-------
        are all subject to erosion, clogging, tearing, shorting,
        or similar problems with time.  As the controls deteriorate,
        the level of emissions is expected to increase.

     5.3.2  Participate Matter Standard for Portland Cement Clinker
            Coolers

     There is not sufficient justification for revision of the pre-

sent standard for clinker coolers based on the following considera-

t ions:

     •  Fabric filters remain the primary control technology for
        removing particulate matter from clinker cooler exhaust gases
        and are identical to those used as the rationale for setting
        the standard in 1971.

     •  The same problems with deterioration apply to both clinker
        cooler and kiln emission control.

     •  An analysis of the compliance test data indicates that the
        current NSPS is set at a level that ensures continuous com-
        pliance with an adequate margin of safety.

     5.3.3  Opacity Standards

     The opacity standard has been studied thoroughly in answer to

a Court remand in 1973.  No changes have occurred in the industry to

invalidate the conclusions of that study.
                                 5-12

-------
6.0  ANALYSIS OF THE IMPACTS OF OTHER ISSUES ON NSPS




6.1  Industry Economics and New Construction




     The historical growth pattern of the cement industry shows its




close ties with the construction industry.  Figure 6-1 displays how




the production of cement has paralleled construction spending in




the U.S. for the period 1966-1977.  It is estimated that cement is




a necessary input to 90 percent of all construction projects and




99 percent of all cement is used in construction (Bureau of Mines,




1976).  The clinker capacity of the industry however has not fol-




lowed this pattern very closely.  Figure 6-2 shows the comparison




of clinker capacity and production for the period 1945 through 1977.




Future capacity and production growth estimates are also shown.  From




this graph, it is obvious that although cement production and con-




struction are closely related, clinker capacity and construction are




not.  A number of external events can be noted which preceded the




wide fluctuations between clinker capacity and production.  These




include a post war housing boom in the late 1940s and early 1950s,




another construction boom in the early 1970s, the Clean Air Act of




1970, New Source Performance Standards in 1971, price and wage con-




trols in 1971, the Clean Air Act Amendments of 1972 and an economic




recession in 1973-1975.




     The cement industry built no "greenfield" plants (plants




constructed at a new site location) during the period 1931 to 1945




(Mongoven, 1977).  During the post-World War II era, the immediate
                                6-1

-------
to
Index of Cement Output
            47-49-100<
                 250


                 240


                 230


                 220


                 210


                 200


                 190


                 180
                                                                                             $ Bil
                                                                                             New Construction
                                                                                             Put in Place
                                                                                             Constant 1967

                                                                                             95
90


85

80


75


70


65


60
                         1966    67    68   69
                       Source:  Mongoven, 1977.
                                             70    71     72    73   74    75    76   77
                                                       FIGURE 6-1
                                      CONSTRUCTION SPENDING AND CEMENT OUTPUT

-------
  100
   90-
 8  do
 o
   70

   60
5
50

40

30
             Clinker Capacity

             Production

             Projection
      1948  50
                    55
60
65
70
75
80
85
     Source:  Bureau of Mines,  1978.
                                      FIGURE 6-2
                   U.S. PORTLAND CEMENT CAPACITY AND PRODUCTION

-------
demand  for  cement by  the construction  industry was met by capacity




released  from war production.  In  1947 the  industry utilization of




capacity  was 75 percent (Bureau of Mines, 1973).  This steadily




increased to greater  than 90 percent utilization during 1953-1956




with  the  post-war housing boom and peaked in 1955 at 94.3 percent




(Bureau of  Mines, 1973).  Due to the regional nature of the industry,




regional  shortages were encountered while the industry was realizing




greater than 15 percent return on sales (Mongoven, 1977).




     During the period 1955-1967, cement production capacity in-




creased 61.4 percent, approximately two-thirds of the total post war




increase  occurring in this 12-year period (Bureau of Mines, 1973).




Figure 6-3  shows that although a relatively large number of kilns




built prior to 1946 (20 percent) are still operating, these kilns




account for only 10 percent of clinker capacity.  In the early 1960s,




the industry was faced with overcapacity.  The utilization of pro-




duction capacity dropped to less than 80 percent (Bureau of Mines,




1973).  Where production had increased 50 percent during the 1950s,




production  increased only 15 percent during the 1960s (Bureau of




Mines, 1973).




     In the late 1960s and early 1970s, utilization of production




capacity  slowly climbed once again to greater than 90 percent in




1972-1973 (Bureau of Mines, 1973).  At the time, little new capacity




was built, while older plants were closed due to age and the new




pollution control standards.   Several existing cement plants closed




because industry did not feel that the additional capital cost for







                                 6-4

-------
Ui
*v
'
15
?
o
4J
s
^ 10
4J
•H
O
01
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^
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^
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Wet Process

Dry Process
Total
••
MH
^
^



S



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l?
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i ;.;.



-J\
^*

ft: ;i


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07 1 A
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Prior to 1931- 1936- 1941-

















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s
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k ,
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9.3







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1
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^
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1951- 1956- 19














6]
i
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.-

^
x
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X
ss
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5.5









0.0
L96 - 1971- 1976-
1955 1960 1965 1970 1975 1977
         Source:  Portland Cement Assn,  1978.
                                              FIGURE 6-3
                                   CEMENT PLANT CLINKER CAPACITY
                                            BY AGE OF KILN

-------
pollution control equipment could be justified at obsolete plants.

According to Daugherty and Wist (1974) 15 plants had closed due

chiefly to environmental pressures.  Figure 6-4 shows the age and

number of kilns presently operating in the U.S.  A total of 14 per-

cent of these kilns were built prior to 1931 and over 20 percent

prior to 1946.  Rarely are these older facilities closed solely

because of pollution abatement requirements.  The Bureau of Economic

Analysis (Department of Commerce) surveyed 131 industrial closings

over the period 1974-1977 that involved pollution abatement require-

ments.  The hypotheses that they suggested from their survey results

were that:

     •  First, most permanent closings involving pollution problems
        did not occur solely because of pollution abatement
        requirements.

     •  Second, the number of permanent closings fell after 1975 when
        general economic conditions improved.

     •  Third, air pollution requirements contributed to more per-
        manent closings than water pollution requirements, possibly
        because of a combination of the Clean Air Act of 1970 dead-
        line of 1975 and the slack economic conditions in 1974 and
        early 1975 (Rutledge et al., 1978).

     The closings may have been a contributing factor in the regional

lack of capacity in 1972-1973.  It is more likely, however, that this

shortage was a result of the price and wage controls imposed in 1971

which held the price of portland cement at a level that ensured the

industry its lowest profit margin since the Depression in the 1930s

(Frondistun-Yannas, 1976).
                                 6-6

-------
a
ti
M
0)
50


45


40


35


30


25


20


15


10


 5
             Wet Process


             Dry Process
  I
         33
            20
                                                        48
                                       24.
                                                                       24
                                                                                 20
                                                                               14
                                                                          10
      Prior to
         1931
            1931-
            1935
1936-
1940
1941
1945
1946
1950
1951-
1955
1956-
1960
1961-   1966-    1971-     1976-
1965    1970    1975      1977
Source:  Portland Cement Assn, 1978.
                                         FIGURE 6-4
                                   CEMENT PLANT KILN AGE

-------
     Decreased capacity and increased demand resulted in high capac-




ity utilization and regional shortages.  This time, however, the




margin on sales, which had slowly climbed to 4 to 5 percent was




restrained by price controls (Mongoven, 1977).  The price controls




put into effect in 1971 used the late 1960s as a base period.  This




period was particularly poor financially for the industry and the




effect was to postpone new construction during what should have been




a particularly profitable period.  The cement industry was one of the




first industries to have controls removed in 1973.  When the controls




were removed, the price of cement jumped 14 percent and new capacity




construction was initiated.  Shortly thereafter, the U.S. entered a




severe recession which left the cement industry with excess capacity.




     By 1975, production had fallen to 64.5 million Mg while capacity




had grown to 92.3 million Mg for a net of 70 percent utilization of




clinker production capacity (Bureau of Mines, 1975).  With excess




capacity came low profit margins again and a lack of investment




capital.  Recent expansion has accompanied the rapid growth in the




construction industry, but the construction industry can increase




demand for cement much faster than the cement industry can increase




capacity.  Parts of the U.S. are already seeing cement shortages,




particularly in the West.  The cement industry, however, is wary of




increasing capacity as it has done in the past, only to discover that




the excessive demand for cement was a short-term phenomenon.
                                 6-8

-------
     As shown in Figure 6-2, the Bureau of Mines projections for the



early 1980s indicate a possibility of high capacity utilization and




possibly regional shortages that usually accompany this trend.  Some




of this effect is already being felt, i.e., East Coast cement plants




are operating at 60 to 65 percent capacity while some West Coast




plants are operating at 100 percent capacity (Business Week, 1977).




Two interesting details are that East Coast manufacturers are




receiving as low as $28/ton while West Coast manufacturers are




receiving as much as $53/ton for an identical product (Business Week,




1977).  Secondly, although the demand is greater in EPA Region IX,




over 50 percent of the capacity completed between 1972 and 1978 was




in EPA Regions IV and V (7.4 percent in Region IX) (Portland Cement




Association, 1978). Also, the projected future growth announced by




the cement industry for 1978 through 1981 indicates less than 30




percent of new kiln capacity will be built in EPA Regions IX and X.




     Table 6-1 shows the current and projected distribution of cement




production capacity in the U.S. as of November 15, 1978.  According




to the Portland Cement Association figures, five new plants will be




completed by 1981, with a combined capacity of 39 million Mg per




year.  Table 6-2 shows all the changes in future cement plant capac-




ity changes announced by the cement industry.  These announcements




indicate an anticipated capacity increase of 2.3 million Mg/year in




EPA Regions IX and X.  This is 30 percent of the total capacity in-




crease of 7.8 million Mg/year of clinker expected by year-end 1981.






                                 6-9

-------
                                                        TABLE 6-1

                                       PORTLAND CEMENT CLINKER PRODUCTION CAPACITY
ON
I
EPA
Region
I
II
III
IV

V
VI




VII

VIII

IX

X
TOTAL

Clinker
Capacity^*
(HHMg/yr)
None
4,248
12,159
14,852

13,337
11,889




10,431

3,942

11,789

2,333
84,980

New
No.
None
1 Dry
3 Dry
7 Dry
4 Wet
9 Dry
2 Dry
3 Wet



4 Dry

1 Dry
3 Wet
2 Dry
1 Wet
None
29 Dry
11 Wet
Kilns 1972-1978a
Capacity (103 Mg/yr)b

490
1,602
3,883
1,744
4,215
753
785



1,123

509
863
720
441
—
13,295
3,833

No.
None
None
None
lDryd
1 Dry
1 Dry
1 Dry
2 Dry
1 Dry
IDry
1 Dry
1 Dry
1 Dry
1 Dry
1 Wet
3 Dry
3 Dry
1 Dry
19 Dry
1 Wet
Announced Growth0
Capacity (10J Mg/yr)
__
-
-
100
1,361
518
499
236
726
205
907
131
603
122
81
483
1,406
454
7,751
81

Year*

-
-
79
81
80
79
79
80
80
NA
78
80
79
79
79
NA
79


              NA = Not Announced
              Q
              .Completion Year
               As of December 31, 1977
              ^As of November 15, 1978
               New plant

              Source:  Portland Cement Assn.,  1978.

-------
                                     TABLE 6-2

                        ANNOUNCED CEMENT/CLINKER CAPACITY CHANGES
                                AS OF NOVEMBER 15, 1978
Year
Plant Name
Location
Process
                                                                  Capacity (10 Mg/yr)
From
                                                                      To
        Difference
1978
1979
1980
1981
No Date
Given
Lehigh
Oregon Portland
Texas Industries
Amcord
Ideal
Ideal
Kaiser
Lone Star
OKC
Utah Portland
General Portland
Kaiser
Marquette
Medusa
Southwestern
Ideal
Lonestar
California
  Portland
Flintkote

Kaiser
Mason City, IA
Durkee, OR
Hunter, TX
Oro Grande, CA
Boettcher, CO
Knoxville, TN
San Antonio, TX
Davenport, CA
Pryor, OK
Salt Lake City,
                                            UT
New Braunfels, TX
Permanente, CA
Cape Girardeau, MO
Charlevoix, MI
Odessa, TX
Theodore, AL
Georgetown, TX

Mojave, CA
Redding & San
  Andreas, CA
Lucerne Valley, CA
 Dry
 Dry
 Dry
 Dry
 Dry
 Dry
 Dry
 Dry
 Dry
 Wet
 Dry
 Dry
 Dry
 Dry
 Dry
 Dry



 Dry

 Dry

 D-W
 Wet
 549    680       131

  SUBTOTAL 1978  +131
1041
 295
 426
 713
 358
 390
 318
 454
 499
1247
 417
 526
 713
 635
 626
 399
454
499
206
122
100
 0
277
236
 81
                                                                SUBTOTAL 1979 +1975
                                                              1450
                                                               304
                                                               698
                                                               249
        726
       1450
        907
       1216
        454
           726
            0
           603
           518
           205
  SUBTOTAL 1980 +2052

 —    1361      1361

 SUBTOTAL 1981  +1361
        907
                                                              1043   1996
                                                               816
                                                               907
       1270
        907
                                                               SUBTOTAL
                                            TOTAL CHANGE IN DRY PROCESS
                                            TOTAL CHANGE IN WET PROCESS

                                GRAND TOTAL PROCESS CHANGE THROUGH 1981
           907

           953

           453
            0

         +2313

         +7751
            81

         +7832
 Source:  Portland Cement Association, 1978a.
                                         6-11

-------
     The effects of pollution abatement requirements on the cement

industry have been mentioned previously. Rutledge et al.  (1978) hypo-

thesized that air pollution regulations contribute to more industrial

closings than water pollution requirements.  In their survey,  they

found that air pollution problems were cited as a contributory factor

in permanent closings almost twice as often as water pollution prob-

lems.  Daugherty and Wist (1974) reported that in the years prior to

1974, 15 cement plants were shut down chiefly due to environmental

pressures.  Plant closures are expected to continue as new, energy-

efficient, cement plants are built.  These new plants will often

replace older, obsolete equipment in an air pollution and cost mini-

mizing trade-off situation.

     Capital expenditures for air pollution abatement equipment in

the U.S. decreased in 1977 (Rutledge et al., 1978).  In the portland

cement industry, pollution control expenditures average about 10

percent of the total construction costs for a new plant (Mongoven,

1977).  This is a decrease from the estimated 13 percent that EPA

indicated in 1971 in the original background study for the proposed

new-source performance standards.

     The Council on Wage and Price Control (Mongoven, 1977) came to

the following conclusion concerning the effect of pollution abatement

on the cement industry:

     A reduction in the rate of increase in operating costs from 6
     percent to 5 percent will do more to encourage the building of
     new cement capacity than would the reduction in the cost of a


                                  6-12

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     new plant (by eliminating the need for pollution control de-
     vices).  This result suggests that an effective macroeconomic
     stabilization policy could be the most important step in re-
     ducing the possibility of long run material shortages.

     Have the NSPS for Portland Cement Plants stifled new capital

investment? The Council on Wage and Price Stability (Mongoven, 1977)

concluded that:

     ...These figures indicate that the added pollution control costs
     do change the way a firm would consider a new investment deci-
     sion by making larger price increases necessary for the expendi-
     tures to be committed.  This does not mean that the imposition
     of these controls has necessarily caused any reduction in new
     capacity expenditures in the cement industry.  However, this
     analysis does leave open the possibility that an investment de-
     cision could be changed for a marginal plant because of pollu-
     tion control costs.  (Particularly a plant selling cement for
     $40 per ton and using a 12 percent rate of return).

Since cement is already selling for as high as $53 per ton on the

West Coast, it is very likely that capital investment will not be

stifled by pollution control expenditures.

     In conclusion, the following remarks summarize the status of the

cement industry:

     •  Cement production is a regional industry caused by the high-
        volume/low-value nature of the product and high transporta-
        tion costs.

     •  The industry has suffered high excess capacity periods and
        low profits that have stifled capital investment.

     •  Pollution abatement requirements may affect capital invest-
        ment decisions, however, minor changes in future operating
        costs will have a more significant effect.

     •  The current price of cement is sufficient to stimulate new
        capacity construction, regardless of the effect of present
        pollution abatement requirements.
                                 6-13

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6.2  Excessive Emissions During Cement Kiln Startup




     The NSPS specifically exempt affected facilities from the stan-




dard during periods of startup, shutdown, or malfunction.  If a




cement kiln is permitted to operate uncontrolled during the start-up




period, emissions may be estimated as 122 kg/Mg feed (dry process)




and 114 kg/Mg feed (wet process) (EPA, 1977) and greater than 60 per-




cent opacity (PEDCo Environmental, Inc. 1978) for 4-24 hours.




Although startup periods are estimated to be only 2 percent of total




operating time, controlled emissions are so low that startup emis-




sions are a significant -amount of the total kiln emissions.




     During kiln startup, the temperature of the kiln is raised




slowly to reduce the loss of refractory lining. While it is warming




up, a number of combustible materials will be present in the exhaust




stream.  These include carbon monoxide as well as unburned fuel.




Under normal conditions, the emission controls are not bypassed dur-




ing periods of startup and shutdown and cyclones and fabric filters




are not affected by the exhaust stream composition during these peri-




ods.  However, due to the nature of electrostatic precipitator oper-




ations, the internal arcing presents a fire and explosion hazard in




the presence of combustibles.  For this reason ESPs are generally




shut down during kiln startup and provide only settling chamber con-




trol of particulate emissions.  Approximately 40 percent of present




NSPS affected facilities use ESPs for kiln emission control.




     A common operating practice during startup is to gradually en-




ergize the ESP once the inlet gas temperature reaches 177°C (350°F).





                                  6-14

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The ESP is energized gradually to prevent damage to insulators.  In

the case of shutdown, the ESP is left energized so that excessive

emissions are not a problem.

     There is little that can be done to reduce emissions during

cement kiln startup and shutdown when an ESP is used as the control.

The excessive emissions are a result of the limitations of the kiln

and ESP in that the kiln cannot be heated rapidly and the ESP cannot

be activated in the presence of combustibles.  The following sugges-

tions were made by PEDCo Environmental, Inc. (1978) as means of mini-

mizing the excessive emissions:

     1.  Use oil or gas fired preheating on coal fired kilns, then
         switch to coal after the ESP has been energized.

     2.  Use sensors to monitor the ESP inlet gas stream for combus-
         tible gases.  As soon as the gas stream is safe, energize
         the ESP.

     3.  Use a cyclone before the ESP.

6.3  Raw-Mill Bypass

     An issue was raised by EPA Region IV personnel about compliance

during periods of excessive emissions caused by bypassing the raw-

mill on a dry process kiln. Usually the raw-mill feeds raw meal (dry

kiln feed material) to storage from which the kiln is fed.  Kiln ex-

haust passes through the storage and raw-mill to conserve energy by

preheating the feed.  A side benefit of doing this is a reduction in

particulate matter loading in the inlet gas stream to the emission

control device.
                                  6-15

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     However, when the raw-mill produces raw meal at a faster rate

than the kiln is being fed, it must be shut down until the kiln

catches up.  At this time, the kiln exhaust stream bypasses the raw-

mill and goes directly to the emission control device.  The increased

loading to the control device yields increased emissions to the

atmosphere which in turn may make the facility out of compliance.

     The issue was resolved in that raw-mill bypass is considered a

normally accepted operating procedure in the industry and would not

constitute an upset or malfunction operation, thereby qualifying for

an exemption from the NSPS.

6.4  Use of Alternate Fuels

     Most of the NSPS affected facilities use coal as fuel to fire

the kiln and were tested for compliance while using coal.  All but

one kiln was found to be in compliance with the standard.

     Although one would expect the burning of coal to increase par-

ticulate matter loading in the exhaust stream, the fly ash that does

not become incorporated into the clinker is not expected to raise

emissions to the point that they exceed the standard.  It is expected

that the environmental effects of converting from oil or gas to coal

will be primarily the fugitive dust emissions from the handling and

storage of coal (Arthur D. Little, Inc., 1976).  Water pollution

resulting from rainwater runoff from outdoor coal storage piles must

also be controlled.

     No major air pollution effects are anticipated from the conver-

sion to coal from oil and gas.
                                 6-16

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6.5  Gaseous Emissions




     The exhaust streams from cement kilns and clinker coolers con-




tain a number of gaseous species in addition to the particulate mat-




ter.  The vaporized alkaline salts that condense to a fume and are




removed with mineral dust particles have already been discussed.




The following paragraphs discuss those emissions of carbon monoxide,




sulfur oxides and nitrogen oxides which remain in a gaseous state and




are therefore uncontrolled.  Fluorides, hydrocarbons and hydrogen




sulfide may also be emitted.




     6.5.1  Carbon Monoxide




     Carbon monoxide emissions are generally negligible due to the




excess air present in the kiln.  A typical analysis of the kiln ex-




haust gas would have 0 to 2 volume percent carbon monoxide (Daugherty




and Wist, 1974).




     6.5.2  Fluorine




     Fluorine can be released in the kiln from the raw materials and




fuel during the formation of clinker. Tests performed on the cleaned




gas from 11 cement kilns found no gaseous fluorides (Daugherty and




Wist, 1974). This was expected since calcium fluoride is produced in




the presence of excess calcium oxide and the ESP or baghouse is capa-




ble of removing the solid calcium fluoride.




     6.5.3  Hydrocarbons




     Hydrocarbons, principally aldehydes, can result from the dis-




charge of the products of incomplete fuel combustion.  This would
                                  6-17

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ordinarily only occur during startup or malfunction.  Data collected




by Daugherty and Wist (1974) indicate an annual emission of 54 Mg of




hydrocarbons from a 444,000 Mg per year dry process plant and only 34




Mg from a 298,000 Mg/yr wet process plant.




     6.5.4  Hydrogen Sulfide




     Hydrogen sulfide and other odiferous sulfides can be emitted




from a cement plant if certain raw materials such as marl, clay,




shale, and marine shells are used in a wet process kiln.  It is also




possible that a kiln operated under reducing conditions, rather than




the usual excess air conditions, can reduce sulfur oxides to poly-




sulfides and hydrogen sulfide (Daugherty and Wist, 1.974).  Establish-




ing excess air conditions by reducing the fuel supply and increasing




the air supply will control this.




     6.5.5  Nitrogen Oxides




     Cement kilns are a very large source of nitrogen oxides (NOX)




emissions.  The EPA (1974) estimates NOX emissions as 1.3 kg/Mg




of cement produced.  Since 71.4 million Mg of portland cement were




produced in 1977 (Bureau of Mines, 1978), an estimated 93,000 Mg of




NOX were emitted by portland cement plants that year.  According to




the 1975 National Emissions Report, Mineral Products is the second




largest industrial process source of NOX emissions.  In addition,




data presented by Daugherty and Wist (1974) show NOX emissions




ranging from 150 to 1050 ppm.
                                  6-18

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     Nitrogen oxides are formed in the high temperature burning zone




of the cement kiln.  This portion of the kiln is maintained at  tem-




peratures up to 1650°C and under oxidative conditions.   The  gener-




ation of NOX in the kiln cannot be avoided because use  of any other




nonnitrogen containing oxidizing gas would be prohibitively expen-




sive.




     The main factors that result in the production of NOX are the




flame and kiln temperature, the residence time that combustion gases




remain at this temperature, the rate of cooling of these gases, and




the quantity of excess air in the flame.  Control of these factors




may permit the operator to sharply reduce the emission of NOX,  but




at the present time there is no control equipment in cement plants




for NOX emissions.




     It is reported that use of a flash calciner in a suspension pre-




heater will reduce the NOX emitted per ton of cement.  This occurs




because the fuel burned in the calciner is at a lower temperature




that does not favor NOX formation.  The fuel burned in the calciner




reduces the quantity of fuel that must be burned in the kiln as well




as reducing the length of the kiln (shortening residence time)




required for clinker formation, thus reducing NOX formation.




     6.5.6  Sulfur Oxides




     Sulfur oxide (SOX) emissions from cement kilns are essentially




all sulfur dioxide (802) from burning raw meal in the kiln.  The




burned fuel and the raw meal both contribute to the total S02







                                 6-19

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generated.  However, very little of the S(>2 generated is actually

emitted into the atmosphere.  As the S02 is generated, it comes

into direct contact with calcium oxide and alkaline oxides already

formed in the kiln.  Approximately 75 percent of the S02 is sorbed

on the oxide particles and eventually is incorporated in the clinker

(Ketels et al., 1976).  In addition, 50 percent of the remaining

SC>2 is removed by sorption in a fabric filter baghouse by the same

mechanism.

     The uncontrolled emission of SC>2 is estimated by EPA (1977) as

5.1 kg/Mg of cement produced plus the S02 contributed by the fuel:

2.15 kg/Mg for oil and 3.45 kg/Mg for coal.  If all cement plants

were converted to use 3 percent sulfur coal, in a kiln controlled by

a baghouse, then an estimated 186,000 Mg of 862 would have been em-

itted during 1977.  This is a very high estimate and does not take

into consideration the following factors:

     1.  Sulfur content of the kiln feed can vary widely

     2.  Sorption of S02 will be affected by the availability of
         calcium and alkaline oxides which will vary with the kiln
         feed

     3.  The type of process—the mechanism of a suspension
         preheater—should permit greater sorption of S02-

     Only one NSPS cement plant was tested for S02 emissions.  The

Louisville Cement Plant at Speed, Indiana, showed S02 emissions of

0.716 kg/Mg feed with the mill on and 1.517 kg/Mg feed with the mill

off.  These measurements are substantially less than the EPA estimate

of uncontrolled emissions mentioned above.


                                  6-20

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7.0  FINDINGS AND RECOMMENDATIONS

     The primary objective of this report has been to assess  the need

for revision of the existing NSPS for portland cement plants.  The

particulate matter standard is reviewed below.  The existing  opacity

standard was thoroughly reviewed in the report to the U.S. District

Court of Appeals for the District of Columbia in answer to their

remand of the standard to EPA.

7.1  Findings

     7.1.1  Process Emission Control Technology

     •  The current best demonstrated control technology for partic-
        ulate matter emissions has changed since the original stan-
        dard was promulgated only in that kilns equipped with ESPs
        are capable of meeting the standard.   Fabric filter baghouses
        continue to share the position as a best control technology
        since the original standard was based on this type of con-
        trol.  No new developments have occurred in either of these
        technologies to substantiate a reduction in the allowable
        emissions from either kilns or clinker coolers.

     •  Although the measured kiln emissions were as low as 0.013
        kg/Mg feed, there was no indication that this level could
        be maintained or that other units testing as high as  0.142
        kg/Mg feed could emit less.  There was no correlation between
        kiln size, control technology, wet or dry process, and emis-
        sion rate.

     •  The range of emission rates for clinker coolers (0.005 kg/Mg
        to 0.43 kg/Mg feed) also showed no correlation with known
        variables or that these levels could be maintained with age.

     •  Both the kiln and clinker coolers are presently required to
        reduce emissions greater than 99 percent.

     7.1.2  Economic Considerations
        The cement industry is a capital and energy intensive indus-
        try that has had difficulty attracting capital investment due
        to low profitability in past years.
                                  7-1

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     •  The cost of pollution controls to the cement industry is
        approximately 10 percent of capital investment at the pre-
        sent time.

     •  The U.S. is currently entering a period of cement capacity
        shortage and increased pollution abatement costs will have
        an effect on investment decisions.

     7.1.3  Gaseous Emissions

     •  The emissions of carbon monoxide, hydrocarbons, fluorides,
        and hydrogen sulfide are not significant.

     •  Sulfur dioxide emissions are controlled substantially (nearly
        90 percent) already, without a standard.  It is not known if
        emissions can be reduced beyond that level.

     •  Nitrogen oxides are emitted from cement kilns in large quan-
        tities.  There are no known controls for these emissions.
        Possible methods of reducing the quantity of NOX emitted
        have not been tested.

7.2  Recommendations
     7.2.1  Opacity NSPS

     There is no justification for changing the opacity standard for

any portion of the portland cement plant.

     7.2.2  Particulate Matter NSPS

     There is no justification for changing the particulate matter

standard for either the kiln or clinker cooler because:

     •  The best demonstrated control technologies, ESP and/or bag-
        house, are currently in use at all new portland cement
        plants.

     •  The current standard requires greater than 99 percent reduc-
        tion in emissions, which is the maximum for these control
        technologies.
                                 7-2

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     7.2.3  Gaseous Emissions



     It is recommended that a monitoring program be initiated to




determine the actual emission rate of 802 an<* N0x from port land




cement kilns.




     It is further recommended that research and development be




conducted to find means for reducing NOX emissions.
                                 7-3

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8.0  REFERENCES

Arthur D. Little, Inc., 1976.  Environmental Considerations of
     Selected Energy Conserving Manufacturing Process Options:
     Volume X.  Cement Industry Report.  PB-264 276.  NTIS,
     Springfield, Va.

Bowker, A.H. and G.J. Lieberman, 1963.  Engineering Statistics
     (Fifth Printing), Prentice-Hall, Inc., Englewood Cliffs, N.J.

Business Week, 1977.  Cement's Bad Case of Regional Softness.
     November 14.  p. 41.

Chemical and Engineering News, 1978.  Chemical Flue Gas Conditioning
     Growing In Use.  October 9.  p. 14.

Daugherty, K.E. and A.O. Wist, 1974.  Air Pollution in the Cement
     Industry.  In Recent Advances in Air Pollution Control.  AIChE
     Symposium Service, 70 (137):50-55.

Davis, T.A. and D.B. Hooks, 1975.   Disposal and Utilization of Waste
     Kiln Dust from the Cement Industry.  EPA-670/2-75-043.  NTIS,
     Springfield, Va.

Frondistou-Yannas, S.A., 1976.  The Hydraulic Cement Industry in
     the United States, A State-of-the-Art Review.   Massachusetts
     Institute of Technology.  PB-265 874.  NTIS,  Springfield, Va.

Gieseke, J.A. and E.W. Schmidt, 1978.  Characteristics of Dust in
     Collector Selection.   Battelle Columbus Laboratories.  In
     Pollution Control Short Course, Apr. 24-28, 1978, Portland
     Cement Association, Skokie, 111.

Retels, P.A., J.D. Nesbitt, and R.D. Oberle, 1976.   Survey of Emis-
     sions Control and Combustion Equipment Data in Industrial
     Process Heating.  Institute of Gas Technology.  PB-263 453.
     NTIS, Springfield, Va.

Rohanowski, F.I. and J.L. Shy, 1978.  Second-generation Precalcining
     with By-pass Alternatives for Alkali Control.   Allis-Chalmers
     Corp.  In Proceedings of the International 13th Cement Seminar.
     Maclean-Hunter Publishing Corporation, Chicago, 111.

Lind, J.H.  Electrostatic Precipitators.  F.L. Smith & Co.  In
     Pollution Control Short Course, Apr. 24-28, 1978, Portland
     Cement Association, Skokie, 111.
                                 8-1

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MITRE Corporation, 1978.  Follow-up communications to Watson et al.,
     1978, with EPA Regional Offices, State Air Pollution Control
     Offices, and cement plant representatives.

Mongoven, J., 1977.  Prices and Capacity Expansion in the Cement
     Industry.  Executive Office of the President, Council on Wage
     and Price Stability, Washington, D.C.

PEDCo Environmental, Inc., 1978.  A Review of Particulate Emission
     Problems During Cement Kiln Start-up.  (Preliminary Draft).
     Cincinnati, Ohio.

Portland Cement Association, 1978.  U.S. Portland Cement Industry:
     Plant Information Summary.  December 31, 1977.  Skokie, 111.

Portland Cement Association, 1978a.  Announced Cement/Clinker Capac-
     ity Changes as of November 15, 1978.  Personal communication
     with T.R. O'Connor, Director, Economic Research Department,
     Skokie, 111.

Research Triangle Institute, 1970.  Establishment of National Emis-
     sion Standards for Stationary Sources, Volume VI, Portland
     Cement Manufacturing Plants.  Research Triangle Park, N.C.

Rutledge, G.L., F.J. Dreiling, and B.C. Dunlap, 1978.  Capital Expen-
     ditures by Business for Pollution Abatement, 1973-77 and Planned
     1978.  In. Survey of Current Business, June 1978.  U.S.
     Department of Commerce, Washington, D.C.

Schumway, R.E, , D.W. Janocik, and C.U. Pierson, 1978.  The Applica-
     tion of Gravel Bed Filters on Clinker Cooler Vents.  Rexnord
     Inc.  In_ Pollution Control Short Course, Apr. 24-28, 1978,
     Portland Cement Association, Skokie, 111.

U.S. Department of Health, Education, and Welfare, 1967.  Atmospheric
     Emissions from the Manufacture of Portland Cement.  Cincinnati,
     Ohio.

U.S. Department of Interior, Bureau of Mines, 1973.  Cement.  Miner-
     als Yearbook, 1972.  Washington, D.C.

U.S. Department of Interior, Bureau of Mines, 1975.  Cement.  Miner-
     als Yearbook, 1974.  Washington, D.C.

U.S. Department of Interior, Bureau of Mines, 1976.  Cement.  Miner-
     als Yearbook, 1975.  Washington, D.C.
                                8-2

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U.S. Department of Interior, Bureau of Mines, 1978.  Cement.
     December 1977.  Mineral Industry Surveys.  Washington, D.C.

U.S. Environmental Protection Agency, 1974.  EPA Response to Remand
     Ordered by U.S. Court of Appeals for the District of Columbia in
     Portland Cement Association v. Ruckelshaus.  EPA-450/2-74-023.
     Research Triangle Park, N.C.

U.S. Environmental Protection Agency, 1977.  Compilation of Air Pol-
     lutant Emission Factors, Third Edition, AP-42.  Office of Air
     Quality Planning and Standards, Research Triangle Park, N.C.

U.S. Environmental Protection Agency, 1978.  1975 National Emissions
     Report.  National Emissions Data System of the Aerometric and
     Emissions Reporting System.  EPA-450/2-78-020.  Office of Air
     Planning and Standards, Research Triangle Park, N.C.

Watson, J.W., L.J. Duncan, E.L. Keitz, and K.J. Brooks, 1978.
     Regional Views on NSPS for Selected Categories.  MTR-7772.
     MITRE Corporation, McLean, Va.
                                8-3

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                                    TECHNICAL REPORT DATA
                             (Please read Instructions on the reverse before completing)
1. REPORT NO.
      EPA-450/3-79-012
                               2.
                                                             3. RECIPIENT'S ACCESSION NO.
4. TITLE ANDSUBTITLE
      A Review of Standards of Performance  for New
      Stationary Sources  - Portland Cement Industry
              5. REPORT DAT6
                  October  1978
              6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
       Kris W. Barrett
              8. PERFORMING ORGANIZATION REPORT NO.

                 MTR-7982
9. PERFORMING ORGANIZATION NAME AND ADDRESS

  Metrek Division of the MITRE Corporation
  1820 Do!ley  Madison Boulevard
  Me Lean, VA   22102
              10. PROGRAM ELEMENT NO.
              11. CONTRACT/GRANT NO.

                68-02-2526
12. SPONSORING AGENCY NAME AND ADDRESS
  DAA for Air  Quality Planning and Standards
  Office of Air,  Noise, and  Radiation
  U.  S. Environmental Protection Agency
  Research Triangle Park, NC  27711	
              13. TYPE OF REPORT AND PERIOD COVERED
              14. SPONSORING AGENCY CODE
                EPA   200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
      This report reviews  the current  Standards of Performance for New Stationary
      Sources:  Subpart  F  - Portland Cement Plants.   It  includes a summary  of the
      current standards, the status of current applicable  control technology, and
      the ability of  plants to meet the current standards.   No changes to the existing
      standard are recommended, but EPA should continue  evaluation of sulfur oxide
      and nitrogen oxide controls with a view toward  incorporating these emissions
      under the scope of the standard  at a later date.
17.
                                 KEY WORDS AND DOCUMENT ANALYSIS
a.
                   DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS  C. COSATI Field/Group
18. DISTRIBUTION STATEMENT

  Release Unlimited
19. SECURITY CLASS (This Report)
  Unclassified
21. NO. OF PAGES
     83
                                                20. SECURITY CLASS (Thispage)
                                                  Unclassified
                            22. PRICE
EPA Form 2220-1 (Rev. 4-77)   PREVIOUS EDITION is OBSOLETE

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