United States Air and Energy Engineering
Environmental Protection Research Laboratory
Agency Research Triangle Park NC 27711
Research and Development EPA/600/S7-87/007 May 1987
oEPA Project Summary
Lime and Cement Industry
Particulate Emissions: Source
Category Report, Volume II.
Cement Industry
John S. Kinsey
The objective of this study was to de-
velop particulate emission factors
based on cutoff size for inhalable parti-
cles for the cement industry. After a
review of available information charac-
terizing particulate emissions from ce-
ment plants, the data were summa-
rized and rated in terms of reliability.
Size specific emission factors were de-
veloped from these data for the major
processes used in the manufacture of
cement. A detailed process description
was presented with emphasis on fac-
tors affecting the generation of emis-
sions. A replacement for Section 8.6
(Portland Cement Manufacturing) of
EPA report AP-42, A Compilation of Air
Pollutant Emissions Factors, was pre-
pared, containing the size specific emis-
sion factors developed during this pro-
gram.
This Project Summary was devel-
oped by EPA's Air and Energy Engineer-
ing Research Laboratory, Research
Triangle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title {see Project Report or-
dering information at back).
Introduction
The purpose of this program was to
summarize the best available informa-
tion on emissions of inhalable particu-
late matter in the cement industry. The
main objective of the program was to
develop reliable size-specific emission
factors for the various processes used in
the production of cement. Both uncon-
trolled and controlled emission factors
are presented in the report. The uncon-
trolled factors represent emissions
which would result if the particulate
control device (baghouse, ESP, etc.)
were bypassed, and the controlled fac-
tors represent emissions emanating
from a particular type of control system.
The size-specific emission factors are
generally based on the results of simul-
taneous sampling at the inlet and outlet
of the control device(s), utilizing a vari-
ety of particle sizing techniques. Other
objectives of this program were to
present current information on the ce-
ment industry as well as prepare a re-
placement for Section 8.6 in EPA report
AP-42, "A Compilation of Air Pollutant
Emissions Factors."
The above objectives were met by a
thorough literature search which in-
cluded:
Data from the inhalable particulate
characterization program.
Fine Particle Emissions Inventory
System (FPEIS).
AP-42 background file at EPA's Of-
fice of Air Quality Planning and
Standards (OAQPS).
State and local air pollution control
agencies.
Various industry sources (e.g.,
Portland Cement Association).
The emission data contained in the
reference documents were reviewed,
analyzed, summarized, and ranked ac-
cording to the criteria established by
OAQPS as published in the EPA report,
"Technical Procedures for Developing
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AP-42 Emission Factors and Preparing
AP-42 Sections," April 1980. After rank-
ing the data, emission factors were cal-
culated using the highest quality data
available. The quality of the data used to
develop each emission factor is indi-
cated by the emission factor rating.
Process control system operating
data as well as general industry infor-
mation were also obtained and summa-
rized as general background informa-
tion. It was not part of this program to
provide detailed engineering analyses,
product specifications, or a detailed
evaluation of trends in the industry.
Summary of Results
Portland cement manufacture ac-
counts for about 98% of the cement pro-
duction in the U.S. The more than 30
raw materials used to make cement
may be divided into four basic compo-
nents: lime (calcareous), silica
(siliceous), alumina (argillaceous), and
iron (ferriferous).
In the dry process, the moisture con-
tent of the raw material is reduced to
less than 1%, either before or during the
grinding operation. The dried materials
are then pulverized and fed directly into
a rotary kiln. The material is dried, de-
carbonated, and calcined as it travels
through the heated kiln and finally
burns to incipient fusion and forms the
clinker. The clinker is cooled, mixed
with about 5% gypsum by weight, and
ground to the final fineness. The
product, cement, is then stored for later
packaging and shipment.
In the wet process, a slurry is made by
adding water to the initial grinding op-
eration. Proportioning may take place
before or after the grinding step. After
the materials are mixed, the excess
water is removed and final adjustments
are made for the desired composition.
This final homogeneous mixture is fed
to the kilns as a slurry (30-40% mois-
ture) or as a wet filtrate (about 20%
moisture). The burning, cooling, addi-
tion of gypsum, and storage are then
carried out as in the dry process.
Particulate matter is the primary
emission in the manufacture of Portland
cement. Emissions also include the nor-
mal tombustion products of the fuel
used for heat in the kiln and drying op-
erations, including nitrogen oxides and
small amounts of sulfur oxides.
Dust sources at cement plants are:
(1) quarrying and crushing, (2) raw ma-
terial storage, (3) grinding and blending
(dry process only), (4) clinker produc-
tion and cooling, (5) finish grinding, and
(6) packaging. The largest single point
of emissions is the kiln, which may be
considered to have three units: the feed
system, the fuel firing system, and the
clinker cooling and handling system.
Additional sources of dust are quarry-
ing, raw material and clinker storagj
piles, conveyors, storage silos, loading/
unloading facilities, and paved/unpaved
roads.
Depending upon the emission, the
temperature of the effluents in the plant
in question, and the particulate emis-
sion standards in the area, the cement
industry generally uses mechanical col-
lectors, electrostatic precipitators, fabric
filters, or combinations of these to con-
trol emissions.
The total mass uncontrolled emission
factors for cement manufacturing are
presented in Table 1, and controlled
emission factors are presented in Table
2. Size-specific emission factors for ce-
ment kilns are presented in Table 3, and
for cement clinker coolers, in Table 4.
Table 1. Uncontrolled Emission Factors for Cement Manufacturing'
Emission Factor Rating: E
Sulfur dioxidec
Mineral Gas Oil Coal Nitrogen
Particulateb sourced combustion combustion combustion oxides Lead
Process kg/Mg lb/ton kg/Mg lb/ton kg/Mg lb/ton kg/Mg lb/ton kg/Mg lb/ton kg/Mg lb/ton kg/Mg lb/ton
Dry process kiln
128
256
5.4
10.8
Neg
Neg
2.2S
4.4S
3.6S
7.2S
1.4
2.8
0.06
0.12
Wet process kiln
120
240
5.4
10.8
Neg
Neg
2.2S
4.4S
3.6S
7.2S
1.4
2.8
0.05
0.10
Clinker cooler'
4.6
9.2
Dryers, grinders, etc.f
Wet process
16.0
32.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.01
0.02
Dry process
48.0
96.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.02
0.04
'Units of clinker produced, assuming 5% gypsum in finished cement.
Includes fuel combustion emissions, which should not be calculated separately. Neg = negligible.
S = % sulfur in fuel. Dash = no data. NA = not applicable.
bEmission Factor Rating: B
cFactors account for reactions with alkaline dust, with no controls. One test series for gas- and oil-fired wet process kilns, with limited data,
suggests that 21-45% of S02 can be removed by reactions with the alkaline filter cake, if baghouses are used.
dFrom sulfur in raw materials, which varies with their sources. Factors account for some residual sulfur, because of its alkalinity and affinity for
S02.
*Emission Factor Rating: D.
'Units of cement produced.
2
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Table 2. Controlled Particulate Emission Factors for Cement Manufacturing'
Particulate _ . .
Emission
Control kg/Mg lb/ton factor
Type of source technology clinker clinker rating
Wet process kiln
Baghouse
ESP
0.57
0.39
1.1
0.78
C
C
Dry process kiln
Multiclone
Multiclone
+ ESP
Baghouse
130"
0.34
0.16
260"
0.68
0.32
D
C
B
Clinker cooler
Gravel bed
filter
ESP
Baghouse
0.16
0.048
0.010
0.32
0.096
0.020
C
D
C
Primary limestone
crusherc
Baghouse
0.00051
0.0010
D
Primary limestone
screenc
Baghouse
0.00011
0.00022
D
Secondary limestone
screen and crusher0
Baghouse
0.00016
0.00032
D
Conveyor transferc
Baghouse
0.000020
0.000040
D
Raw mill systemc-d
Baghouse
0.034
0.068
D
Finish mill system"
Baghouse
0.017
0.034
C
*Units of kg particulete/Mg (lb particulate/ton) of clinker produced, except as noted.
ESP = electrostatic precipitator.
b Based on a single test of a dry process kiln fired with a combination of coke and natural gas.
Not generally applicable to a broad cross section of the cement industry.
cUnits of mass of pollutant/mass of raw material processed.
dlncludes mill, air separator, and weigh feeder.
*Includes mill, air separator(s), and one or more material transfer operations. Units of cement
produced.
Table 3. Size Specific Particulate Emission Factors for Cement Kilns'
Emission Factor Rating: D
Cumulative mass % < stated size" Cumulative emission factor < stated size'
Particle
size
Iv-ml
Uncontrolled
Dry
process
kiln with
multiclone'1
Wet
process
kiln with
ESP
Baghouse
Uncontrolled
Wet Dry
process process
Dry process
with
multiclone'1
Wet process
with
ESP
Baghouse
Wet
process
kiln
Dry
process
kiln
Wet
process
kiln
Dry
process
kiln
Wet
process
Dry
process
kg/Mg
lb/ton
kg/Mg
lb/ton
kg/Mg
lb/ton
kg/Mg
lb/ton
kg/Mg
lb/ton
kg/Mg lb/ton
2.6
7.0
18
3.8
64
NA
46
8.4
17
23
46
5.0
10
0.25
0.60
NA
NA
0.073 0.15
S.0
20
NA
14
83
NA
77
24
48
19
38
0.32
0.64
NA
NA
0.13 0.26
10.0
24
42
24
85
NA
84
29
58
54
108
32
64
0.33
0.66
NA
NA
0.14 0.28
1S.0
35
44
31
91
NA
89
43
86
57
114
41
82
0.36
0.72
NA
NA
0.16 0.30
20.0
67
NA
38
98
NA
100
68
136
49
98
0.39
0.78
NA
NA
0.16 0.32
Total mass emission factor
120
240
128
266
130
260
0.39
0.78
0.67
1.1
0.16 0.32
'ESP « electrostatic precipitator. NA = not available. Dash « no data.
*Aerodynamic diameter. Percentages rounded to two significant figures.
«Units of weight of particulata/unit weight of clinker produced, assuming 5% gypsum in finished cement Rounded to two significant figures.
*Based on a single test, and should be used with caution.
3
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Table 4. Size Specific Emission Factors for Clinker Coolers
Emission Factor Rating: E
Cumulative mass % Cumulative emission factor
< stated sizeb < stated sizec
Particle
sizea
(Vm/
Uncontrolled
Gravel bed filter
Uncontrolled
kg/Mg lb/ton
Gravel bed filter
kg/Mg lb/tan
2.5
0.54
40
0.025
0.050
0.064
0.13
5.0
1.5
64
0.067
0.13
0.10
0.20
10.0
8.6
76
0.40
0.80
0.12
0.24
1S.0
21
84
0.99
2.0
0.13
0.26
20.0
34
89
1.6
3.2
0.14
0.28
Total mass emission factor
4.6
9.2
0.16
0.32
"Aerodynamic diameter.
bRounded to two significant figures.
cUnit weight of pollutant/unit weight of clinker produced. Rounded to two significant figures-
John S. Kinsey is with Midwest Research Institute, Kansas City, MO 64110..
Dale L. Harmon is the EPA Project Officer (see below).
The complete report, entitled "Lime and Cement Industry Particulate Emissions:
Source Category Report, Volume II. Cement Industry," (Order No. PB 87-
168 654/AS; Cost: $36.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States Onter for Environmental Research
Environmental Protection Information
Agency Cincinnati OH 45268
Official Business
Penalty for Private Use S300
EPA/600/S7-87/007
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