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EMISSION FACTORS
4/73
-------
References for Section 3.2.1
1. Nature and Control of Aircraft Engine Exhaust Emissions. Northern Research and Engineering Corporation.
Cambridge, Mass. Prepared for National Air Pollution Control Administration. Durham. N.C., under Contract
Number PH22-68-27. November 1968.
2. The Potential Impact of Aircraft Emissions upon Air Quality. Northern Research and Engineering
Corporation, Cambridge, Mass. Prepared for the Environmental Protection Agency, Research Triangle Park,
N.C., under Contract Number 68-02-0085. December 1971.
3. Assessment of Aircraft Emission Control Technology. Northern Research and Engineering Corporation.
Cambridge, Mass. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Con tract Number 68-04-0011. September 1971.
4. Analysis of Aircraft Exhaust Emission Measurements. Cornell Aeronautical Laboratory Inc. Buffalo, N.Y.
Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under Contract Number
68-04-0040. October 1971.
5. Private communication with Dr. E. Karl Bastress. 1KOR Incorporated. Burlington, Mass. November 1972.
4/73 Internal Combustion Engine Sources 3.2.1-9
-------
-------
3.2.2 Locomotives
by David S. Kircher
3.2.2.1 General - Railroad locomotives generally follow one of two use patterns: railyard switching or road-haul
service. Locomotives can be classified on the basis of engine configuration and use pattern into five categories:
2-stroke switch locomotive (supercharged), 4-stroke switch locomotive, 2-stroke road service locomotive
(supercharged), 2-stroke road service locomotive (turbocharged), and 4-stroke road service locomotive.
The engine duty cycle of locomotives is much simpler than many other applications involving diesel internal
combustion engines because locomotives usually have only eight throttle positions in addition to idle and
dynamic brake. Emission testing is made easier and the results are probably quite accurate because of the
simplicity of the locomotive duty cycle.
3.2.2.2 Emissions — Emissions from railroad locomotives are presented two ways in this section. Table 3.2.2-1
contains average factors based on the nationwide locomotive population breakdown by category. Table 3.2.2-2
gives emission factors by locomotive category on the basis of fuel consumption and on the basis of work output
(horsepower hour).
The calculation of emissions using fuel-based emission factors is straightforward. Emissions are simply the
product of the fuel usage and the emission factor. In order to apply the work output emission factor, however, an
Table 3.2.2-1. AVERAGE LOCOMOTIVE
EMISSION FACTORS BASED
ON NATIONWIDE STATISTICS3
Pollutant
Particulatesc
Sulfur oxidesd
(SOX as S02>
Carbon monoxide
Hydrocarbons
Nitrogen oxides
(NOxasN02)
Aldehydes
(as HCHO)
Organic acidsc
Average emissions'3
lb/103gal
25
57
130
94
370
5.5
7
kg/103 liter
3.0
6.8
16
11
44
0.66
0.84
Reference 1.
Based on emission data contained in Table 3.2 2-2
and the breakdown of locomotive use by engine
category in the United States in Reference 1.
Data based on highway diesel data from Reference
2 No actual locomotive participate test data are
available.
Based on a fuel sulfur content of 0 4 percent from
Reference 3
4/73
Internal Combustion Engine Sources
3.2.2-1
-------
Table 3.2.2-2. EMISSION FACTORS BY LOCOMOTIVE ENGINE
CATEGORY3
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide
lb/103gal
kg/103 liter
g/hphr
g/metric hphr
Hydrocarbon
Ib/K^gal
kg/103 liter
g/hphr
g/metric hphr
Nitrogen oxides
(NOxasN02)
lb/103 gal
kg/103 liter
g/hphr
g/metric hphr
Engine category
2-Stroke
supercharged
switch
84
10
3.9
3.9
190
23
8.9
8.9
250
30
11
11
4-Stroke
switch
380
46
13
13
146
17
5.0
5.0
490
59
17
17
2-Stroke
supercharged
road
66
7.9
1.8
1.8
148
18
4.0
4.0
350
42
9.4
9.4
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turbocharged
road
160
19
4.0
4.0
28
3.4
0.70
0.70
330
40
8.2
8.2
4-Stroke
road
180
22
4.1
4.1
99
12
2.2
2.2
470
56
10
10
a Use average factors (Table 3.2.2-1) for pollutants not listed in this table.
additional calculation is necessary. Horsepower hours can be obtained using the following equation:
w=lph
where: w = Work output (horsepower hour)
1 = Load factor (average power produced during operation divided by available power)
p = Available horsepower
h = Hours of usage at load factor (1)
After the work output has been determined, emissions are simply the product of the work output and the
emission factor. An approximate load factor for a line-haul locomotive (road service) is 0.4; a typical switch
engine load factor is approximately 0.06.1
References for Section 3.2.2
1. Hare, C.T. and K.J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part 1. Locomotive Diesel Engines and Marine Counterparts. Final Report.
Southwest Research Institute. San Antonio, Texas Prepared for the Environmental Protection Agency,
Research Triangle Park, N.C., under Contract Number EHA 70-108. October 1972.
2. Young, T.C. Unpublished Data from the Engine Manufacturers Association. Chicago, 111. May 1970.
3. Hanley, G.P. Exhaust Emission Information on Electro-Motive Railroad Locomotives and Diesel Engines.
General Motors Corp. Warren, Mich. October 1971.
3.2.2-2
EMISSION FACTORS
4/73
-------
3.2.3 Inboard-Powered Vessels Revised by David S. Kircher
3.2.3.1 General - Vessels classified on the basis of use will generally fall into one of three categories: commercial,
pleasure, or military. Although usage and population data on vessels are, as a rule, relatively scarce, information on
commercial and military vessels is more readily available than data on pleasure craft. Information on military
vessels is available in several study reports,1"5 but data on pleasure craft are limited to sales-related facts and
figures.6-10
Commercial vessel population and usage data have been further subdivided by a number of industrial and
governmental researchers into waterway classifications' '"16 (for example, Great Lakes vessels, river vessels, and
coastal vessels). The vessels operating in each of these wateiway classes have similar characteristics such as size,
weight, speed, commodities transported, engine design (external or internal combustion), fuel used, and distance
traveled. The wide variation between classes, however, necessitates the separate assessment of each of the waterway
classes with respect to air pollution.
Information on military vessels is available from both the U.S. Navy and the U.S. Coast Guard as a result of
studies completed recently. The U.S. Navy has released several reports that summarize its air pollution assessment
work.3"5 Emission data have been collected in addition to vessel population and usage information. Extensive
study of the air pollutant emissions from U.S. Coast Guard watercraft has been completed by the U.S. Department
of Transportation. The results of this study are summarized in two reports.1 "2 The first report takes an in-depth
look at population/usage of Coast Guard vessels. The second report, dealing with emission test results, forms the
basis for the emission factors presented in this section for Coast Guard vessels as well as for non-military diesel
vessels.
Although a large portion of the pleasure craft in the U.S. are powered by gasoline outboard motors (see section
3.2.4 of this document), there are numerous larger pleasure craft that use inboard power either with or without
"out-drive" (an outboard-like lower unit). Vessels falling into the inboard pleasure craft category utilize either Otto
cycle (gasoline) or diesel cycle internal combustion engines. Engine horsepower varies appreciably from the small
"auxiliary" engine used in sailboats to the larger diesels used in yachts.
3.2.3.2 Emissions
Commercial vessels. Commercial vessels may emit air pollutants under two major modes of operation:
underway and at dockside (auxiliary power).
Emissions underway are influenced by a great variety of factors including power source (steam or diesel), engine
size (in kilowatts or horsepower), fuel used (coal, residual oil, or diesel oil), and operating speed and load.
Commercial vessels operating within or near the geographic boundaries of the United States fall into one of the
three categories of use discussed above (Great Lakes, rivers, coastline). Tables 3.2.3-1 and 3.2.3-2 contain emission
information on commercial vessels falling into these three categories. Table 3.2.3-3 presents emission factors for
diesel marine engines at various operating modes on the basis of horsepower. These data are applicable to any vessel
having a similar size engine, not just to commercial vessels.
Unless a ship receives auxiliary steam from dockside facilities, goes immediately into drydock, or is out of
operation after arrival in port, she continues her emissions at dockside. Power must be made available for the ship's
lighting, heating, pumps, refrigeration, ventilation, etc. A few steam ships use auxiliary engines (diesel) to supply
power, but they generally operate one or more main boilers under reduced draft and lowered fuel rates-a very
inefficient process. Motorships (ships powered by internal combustion engines) normally use diesel-powered
generators to furnish auxiliary power.17 Emissions from these diesel-powered generators may also be a source of
underway emissions if they are used away from port. Emissions from auxiliary power systems, in terms of the
1/75 Internal Combustion Engine Sources 3.2.3-1
-------
Table 3.2.3-1. AVERAGE EMISSION FACTORS FOR
COMMERCIAL MOTORSHIPS BY WATERWAY
CLASSIFICATION
EMISSION FACTOR RATING: C
Emissions3
Sulfur oxides'3
(SOxasSO2)
kg/103 liter
lb/103 gal
Carbon monoxide
kg/103 liter
lb/103 gal
Hydrocarbons
kg/103 liter
lb/103 gal
Nitrogen oxides
(NOxasN02)
kg/103 liter
lb/103 gal
Class0
River
3.2
27
12
100
6.0
50
33
280
Great Lakes
3.2
27
13
110
7.0
59
31
260
i
Coastal
3.2
27
13
110
6.0
50
32
270
Expressed as function of fuel consumed (based on emission data from
Reference 2 and population/usage data from References 11 through 16.
bCalculated, not measured. Based on 0.20 percent sulfur content fuel
and density of 0.854 kg/liter (7.12 Ib/gal) from Reference 17.
GVery approximate particulate emission factors from Reference 2 are
470 g/hr (1.04 Ib/hr). The reference does not contain sufficient
information to calculate fuel-based factors.
quantity of fuel consumed, are presented in Table 3.2.3-4. In some instances, fuel quantities used may not be
available, so calculation of emissions based on kilowatt hours (kWh ) produced may be necessary. For operating
loads in excess of zero percent, the mass emissions (ej) in kilograms per hour (pounds per hour) are given by:
el = klef
where: k = a constant that relates fuel consumption to kilowatt hours,
that is, 3.63 x 10'4 1000 liters fuel/kWh
(1)
or
9.59 xlO'5 1000 gal fuel/kWh
1= the load, kW
f = the fuel-specific emission factor from Table 3.2.3-4, kg/103 liter (lb/103 gal)
3.2.3-2
EMISSION FACTORS
1/75
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1/75
Internal Combustion Engine Sources
3.2.3-3
-------
Table 3.2.3-3. DIESEL VESSEL EMISSION FACTORS BY OPERATIMG MODE3
EMISSION FACTOR RATING: C
Horsepower
200
300
500
600
700
900
1550
1580
2500
3600
Mode
Idle
Slow
Cruise
Full
Slow
Cruise
Full
Idle
Cruise
Full
Idle
Slow
Cruise
Idle
Cruise
Idle
2/3
Cruise
Idle
Cruise
Full
Slow
Cruise
Full
Slow
2/3
Cru ise
Full
Slow
2/3
Cru ise
Full
Emissions
Carbon monoxide
lb/103
gal
210.3
145.4
126.3
142.1
59.0
47.3
58.5
282.5
99.7
84.2
171.7
50.8
77.6
293.2
36.0
223.7
62.2
80.9
12.2
3.3
7.0
122.4
44.6
237.7
59.8
126.5
78.3
95.9
148.5
28.1
41.4
62.4
kg/103
liter
25.2
17.4
15.1
17.0
7.1
5.7
7.0
33.8
11.9
10.1
20.6
6.1
9.3
35.1
4.3
26.8
7.5
9.7
1.5
0.4
0.8
14.7
5.3
28.5
7.2
15.2
9.4
11.5
17.8
3.4
5.0
7.5
Hydrocarbons
lb/103
gal
391.2
103.2
170.2
60.0
56.7
51.1
21.0
118.1
44.5
22.8
68.0
16.6
24.1
95.8
8.8
249.1
16.8
17.1
0.64
1.64
16.8
22.6
14.7
16.8
21.3
60.0
25.4
32.8
29.5
kg/103
liter
46.9
12.4
20.4
7.2
6.8
6.1
2.5
14.1
5.3
2.7
8.2
2.0
2.9
11.5
1.1
29.8
2.0
2.1
0.1
0.2
2.0
2.7
1.8
2.0
2.6
7.2
3.0
4.0
3.5
Nitrogen oxides
(NOX asN02)
lb/103
gal
6.4
207.8
422.9
255.0
337.5
389.3
275.1
99.4
338.6
269.2
307.1
251.5
349.2
246.0
452.8
107.5
167.2
360.0
39.9
36.2
37.4
371.3
623.1
472.0
419.6
326.2
391.7
399.6
367.0
358,6
339.6
307.0
kg/103
liter
0.8
25.0
50.7
30.6
40.4
46.7
33.0
11.9
40.6
32.3
36.8
30.1
41.8
29.5
54.2
12.9
20.0
43.1
4.8
4.3
4.5
44.5
74.6
5.7
50.3
39.1
46.9
47.9
44.0
43.0
40.7
36.8
^Reference 2.
Participate and sulfur oxides data are not available.
3.2.3-4
EMISSION FACTORS
1/75
-------
Table 3.2.3-4. AVERAGE EMISSION FACTORS FOR DIESEL-POWERED ELECTRICAL
GENERATORS IN VESSELSa
EMISSION FACTOR RATING: C
Rated
output.b
kW
20
40
200
500
Load,c
% rated
output
0
25
50
75
0
25
50
75
0
25
50
75
0
25
50
75
Emissions
Sulfur oxides
(SOxasSO2)d
lb/103
gal
27
27
27
27
27
27
27
27
27
27
27
27
27
27
27
27
kg/103
liter
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
Carbon
monoxide
lb/103
gal
150
79.7
53.4
28.5
153
89.0
67.6
64.1
134
97.9
62.3
26.7
58.4
53.4
48.1
43.7
kg/103
liter
18.0
9.55
6.40
3.42
18.3
10.7
8.10
7.68
16.1
11.7
7.47
3.20
7.00
6.40
5.76
5.24
Hydro-
carbons
lb/103
gal
263
204
144
84.7
584
370
285
231
135
33.5
17.8
17.5
209
109
81.9
59.1
kg/103
liter
31.5
24.4
17.3
10.2
70.0
44.3
34.2
27.7
16.2
4.01
2.13
2.10
25.0
13.0
9.8
7.08
Nitrogen oxides
(NOxasN02>
lb/103
gal
434
444
477
495
214
219
226
233
142
141
140
137
153
222
293
364
kg/103
liter
52.0
53.2
57.2
59.3
25.6
26.2
27.1
27.9
17.0
16.9
16.8
16.4
18.3
26.6
35.1
43.6
Reference 2.
Maximum rated output of the diesel-powered generator.
cGenerator electrical output (for example, a 20 kW generator at 50 percent load equals 10 kW output).
Calculated, not measured, based on 0.20 percent fuel sulfur content and density of 0.854 kg/liter (7.12 Ib/gal) from Reference 17.
At zero load conditions, mass emission rates (ei) may be approximated in terms of kg/hr (Ib/hr) using the
following relationship:
el - klratedef
where: k = a constant that relates rated output and fuel consumption,
that is, 6.93xlO-5 1000 liters fuel/kW
(2)
or
1000 gal fuel/kW
1.83xlO'5
Crated = the rated output, kW
ef = the fuel-specific emission factor from Table 3.2.3-4, kg/103 liter (lb/103 gal)
Pleasure craft. Many of the engine designs used in inboard pleasure craft are also used either in military vessels
(diesel) or in highway vehicles (gasoline). Out of a total of 700,000 inboard pleasure craft ;egistered in the United
States in 1972, nearly 300,000 were inboard/outdrive. According to sales data, 60 to 70 percent of these
1/75
Internal Combustion Engine Sources
3.2.3-5
-------
inboard/outdrive craft used gasoline-powered automotive engines rated at more ihan 130 horsepower. The
remaining 400,000 pleasure craft used conventional inboard drives that were powered by a variety of powerplants,
both gasoline and diesel. Because emission data are not available for pleasure craft, Coast Guard and automotive
data2'19 are used to characterize emission factors for this class of vessels in Table 3.2.3-5.
Military vessels. Military vessels are powered by a wide variety of both diesel and steam power plants. Many of the
emission data used in this section are the result of emission testing programs conducted by the U.S. Navy and the
U.S. Coast Guard.1"3'5 A separate table containing data on military vessels is not provided here, but the included
tables should be sufficient to calculate approximate military vessel emissions.
TABLE 3.2.3.-5. AVERAGE EMISSION FACTORS FOR INBOARD PLEASURE CRAFT3
EMISSION FACTOR RATING: D
Pollutant
Sulfur oxides0'
(SOX as SC-2)
Carbon monoxide
Hydrocarbons
Nitrogen oxides
(NOX as NO2)
Based on fuel consumption
Diesel engine'3
kg/103
liter
3.2
17
22
41
lb/103
gal
27
140
180
340
Gasoline engine0
kg/103
liter
0.77
149
10.3
15.7
lb/103
gal
6.4
1240
86
131
Based on operating time
Diesel engine"
kg/hr
-
-
Ib/hr
_
_
-
Gasoline engine0
kg/hr
0.008
1.69
0.117
0.179
Ib/hr
0.019
3.73
0.258
0.394
aAverage emission factors are based on the duty cycle developed for large outboards (> 48 kilowatts or > 65 horsepower) from Refer-
ence 7. The above factors take into account the impact of water scrubbing of underwater gasoline engine exhaust, also from Reference
7. All values given are for single engine craft and must be modified for multiple engine vessels.
bBased on tests of diesel engines in Coast Guard vessels. Reference 2.
cBased on tests of automotive engines, Reference 19. Fuel consumption of 11.4 liter/hr (3 gal/hr) assumed The resulting factors are
only rough estimates.
dBased on fuel sulfur content of 0.20 percent for diesel fuel and 0.043 percent for gasoline from References 7 and 17. Calculated using
fuel density of 0.740 kg/liter (6.17 Ib/gal) for gasoline and 0.854 kg/liter (7.12 Ib/gal) for diesel fuel.
References for Section 3.2.3
1. Walter, R. A., A. J. Broderick, J. C. Sturm, and E. C. Klaubert. USCG Pollution Abatement Program: A
Preliminary Study of Vessel and Boat Exhaust Emissions. U.S. Department of Transportation, Transportation
Systems Center. Cambridge, Mass. Prepared for the United States Coast Guard, Washington, D.C. Report No.
DOT-TSC-USCG-72-3. November 1971. 119 p.
3.2.3-6
EMISSION FACTORS
1/75
-------
2. Souza, A. F. A Study of Emissions from Coast Guard Cutters. Final Report. Scott Research Laboratories, Inc.
Plumsteadville, Pa. Prepared for the Department of Transportation, Transportation Systems Center,
Cambridge, Mass., under Contract No. DOT-TSC-429. February 1973.
3. Wallace, B. L. Evaluation of Developed Methodology for Shipboard Steam Generator Systems. Department of
the Navy. Naval Ship Research and Development Center. Materials Department. Annapolis, Md. Report No.
28-463. March 1973. 18 p.
4. Waldron, A. L. Sampling of Emission Products from Ships' Boiler Stacks. Department of the Navy. Naval Ship
Research and Development Center. Annapolis, Md. Report No. 28-169. April 1972. 7 p.
5. Foernsler, R. 0. Naval Ship Systems Air Contamination Control and Environmental Data Base Programs;
Progress Report. Department of the Navy. Naval Ship Research and Development Center. Annapolis, Md.
Report No. 28-443. February 1973. 9 p.
6. The Boating Business 1972. The Boating Industry Magazine. Chicago, 111. 1973.
7. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report Part 2. Outboard Motors. Southwest Research Institute. San
Antonio, Tex. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract No. EHS 70-108. January 1973. 57 p.
8. Hurst, J. W. 1974 Chrysler Gasoline Marine Engines. Chrysler Corporation. Detroit, Mich.
9. Mercruiser Sterndrives/ Inboards 73. Mercury Marine, Division of the Brunswick Corporation. Fond du Lac,
Wise. 1972.
10. Boating 1972. Marex. Chicago, Illinois, and the National Association of Engine and Boat Manufacturers.
Greenwich, Conn. 1972. 8 p.
11. Transportation Lines on the Great Lakes System 1970. Transportation Series 3. Corps of Engineers, United
States Army, Waterborne Commerce Statistics Center. New Orleans, La. 1970. 26 p.
12. Transportation Lines on the Mississippi and the Gulf Intracoastal Waterway 1970. Transportation Series 4.
Corps of Engineers, United States Army, Waterborne Commerce Statistics Center. New Orleans, La. 1970. 232
P-
13. Transportation Lines on the Atlantic, Gulf and Pacific Coasts 1970. Transportation Series 5. Corps of
Engineers. United States Army. Waterborne Commerce Statistics Center. New Orleans, La. 1970. 201 p.
14. Schueneman, J. J. Some Aspects of Marine Air Pollution Problems on the Great Lakes. J. Air Pol. Control
Assoc. 14:23-29, September 1964.
15. 1971 Inland Waterborne Commerce Statistics. The American Waterways Operations, Inc. Washington, D.C.
October 1972. 38 p.
16. Horsepower on the Inland Waterways. List No. 23. The Waterways Journal. St. Louis, Mo. 1972. 2 p.
17. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part 1. Locomotive Diesel Engines and Marine Counterparts. Southwest
Research Institute. San Antonio, Tex. Prepared for the Environmental Protection Agency, Research Triangle
Park, N.C., under Contract No. EHS 70-108. October 1972. 39 p.
18. Pearson, J. R. Ships as Sources of Emissions. Puget Sound Air Pollution Control Agency. Seattle, Wash.
(Presented at the Annual Meeting of the Pacific Northwest International Section of the Air Pollution Control
Association. Portland, Ore. November 1969.)
19. Study of Emissions from Light-Duty Vehicles in Six Cities. Automotive Environmental Systems, Inc. San
Bernardino, Calif. Prepared for the Environmental Protection Agency, Research Triangle Park, N.C., under
Contract No. 68-04-0042. June 1971.
1/75 Internal Combustion Engine Sources 3.2.3-7
-------
-------
3.2.4 Outboard-Powered Vessels
by David S. Kircher
3.2.4.1 General — Most of the approximately 7 million outboard motors in use in the United States are 2-stroke
engines with an average available horsepower of about 25. Because of the predominately leisure-time use of
outboard motors, emissions related to their operation occur primarily during nonworking hours, in rural areas,
and during the three summer months. Nearly 40 percent of the outboards are operated in the states of New York,
Texas, Florida, Michigan, California, and Minnesota. This distribution results in the concentration of a large
portion of total nationwide outboard emissions in these states.1
3.2.4.2 Emissions — Because the vast majority of outboards have underwater exhaust, emission measurement is
very difficult. The values presented in Table 3.2.4-1 are the approximate atmospheric emissions from outboards.
These data are based on tests of four outboard motors ranging from 4 to 65 horsepower.1 The emission results
from these motors are a composite based on the nationwide breakdown of outboards by horsepower. Emission
factors are presented two ways in this section: in terms of fuel use and in terms of work output (horsepower
hour). The selection of the factor used depends on the source inventory data available. Work output factors are
used when the number of outboards in use is available. Fuel-specific emission factors are used when fuel
consumption data are obtainable.
Table 3.2.4-1. AVERAGE EMISSION FACTORS FOR OUTBOARD MOTORS3
EMISSION FACTOR RATING: B
Pollutant13
Sulfur oxidesd
(SOxasSO2)
Carbon monoxide
Hydrocarbons6
Nitrogen oxides
(NOxasN02)
Based on fuel consumption
lb/103gal
6.4
3300
1100
6.6
kg/103 liter
0.77
400
130
0.79
Based on work output0
g/hphr
0.49
250
85
0.50
g/metric hphr
0.49
250
85
0.50
a Reference 1. Data in this table are emissions to the atmosphere, A portion of the exhaust remains behind in
the water.
Paniculate emission factors are not available because of the problems involved with measurement from an
underwater exhaust system but are considered negligible.
c Horsepower hours are calculated by multiplying the average power produced during the hours of usage by
the population of outboards in a given area. In the absence of data specific to a given geographic area, the
hphr value can be estimated using average nationwide values from Reference 1. Reference 1 reports the
average power produced (not the available power) as 9 1 hp and the average annual usage per engine as 50
hours. Thus, hphr = (number of outboards) (9.1 hp) (50 hours/outboard-year) Metric hphr = 0.9863 hphr.
Based on fuel sulfur content of 0.043 percent from Reference 2 and on a density of 6.17 Ib/gal
e Includes exhaust hydrocarbons only. No crankcase emissions occur because the majority of outboards are
2-stroke engines that use crankcase induction. Evaporative emissions are limited by the widespread use of
unvented tanks.
4/73
Internal Combustion Engine Sources
3.2.4-1
-------
References for sections 3.2.4
1. Hai£, C.T. and K.J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Part II, Outboard Motors. Final Report. Southwest Research Institute. San
Antonio, Texas. Prepared for the Environmental Protection Agency. Research Triangle Park, N.C., under
Contract Number EHS 70-108. January 1973.
2. Hare. C.T. and K.J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related Equipment
Using Internal Combustion Engines. Emission Factors and Impact Estimates for Light-Duty Air-Cooled Utility
Engines and Motorcycles. Southwest Research Institute. San Antonio, Texas. Prepared for the Environmental
Protection Agency, Research Triangle Park, N.C., under Contract Number EHS 70-108. January 1972.
3.2.4-2 EMISSION FACTORS 4/73
-------
3.2.5 Small, General Utility Engines Revised by Charles C. Masser
3.2.5.1 General-This category of engines comprises small 2-stroke and 4-stroke, air-cooled, gasoline-powered
motors. Examples of the uses of these engines are: lawnmowers. small electric generators, compressors, pumps,
minibikes, snowthrowers, and garden tractors. This category does not include motorcycles, outboard motors, chain
saws, and snowmobiles, which are either included in other parts of this chapter or are not included because of the
lack of emission data.
Approximately 89 percent of the more than 44 million engines of this category in service in the United States
are used in lawn and garden applications.1
3.2.5.2 Emissions—Emissions from these engines are reported in Table 3.2.5-1. For the purpose of emission
estimation, engines in this category have been divided into lawn and garden (2-stroke), lawn and garden (4-stroke),
and miscellaneous (4-stroke). Emission factors are presented in terms of horsepower hours, annual usage, and fuel
consumption.
References for Section 3.2.5
1. Donohue, J. A., G. C. Hardwick, H. K. Newhall, K. S. Sanvordenker, and N. C. Woelffer. Small Engine Exhaust
Emissions and Air Quality in the United States. (Presented at the Automotive Engineering Congress, Society of
Automotive Engineers, Detroit. January 1972.)
2. Hare, C. T. and K. J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related
Equipment Using Internal Combustion Engines. Part IV, Small Air-Cooled Spark Ignition Utility Engines.
Final Report. Southwest Research Institute. San Antonio, Tex. Prepared for the Environmental Protection
Agency, Research Triangle Park, N.C., under Contract No. EHS 70-108. May 1973.
1/75 Internal Combustion Engine Sources 3.2.5-1
-------
Table 3.2.5-1. EMISSION FACTORS FOR SMALL, GENERAL UTILITY ENGINESa'b
EMISSION FACTOR RATING: B
Engine
2-Stroke, lawn
and garden
g/hphr
g/metric
hphr
g/gal of
fuel
g/unit-
year
4-Stroke, lawn
and garden
g/hphr
g/metric
hphr
g/gal of
fuel
g/unit-
year
4-Stroke
miscellaneous
g/hphr
g/metric
hphr
g/gal of
fuel
g/unit-
year
Sulfur
oxidesc
|SOX as S02)
0.54
0.54
1.80
38
0.37
0.37
2.37
26
0.39
0.39
2.45
30
Paniculate
7.1
7.1
23.6
470
0.44
0.44
2.82
31
0.44
0.44
2.77
34
Carbon
monoxide
486
486
1,618
33,400
279
279
1,790
19,100
250
250
1,571
19,300
Hydrocarbons
Exhaust
214
214
713
14,700
23.2
23.2
149
1,590
15.2
15.2
95.5
1,170
Evaporative
—
-
-
113
-
-
-
113
—
-
-
290
Nitrogen
oxides
(NOX as N02)
1.58
1.58
5.26
108
3.17
3.17
20.3
217
4.97
4.97
31.2
384
Alde-
hydes
(HCHO)
2.04
2.04
6.79
140
0.49
0.49
3.14
34
0.47
0.47
2.95
36
Reference 2.
Values for g/unit-year were calculated assuming an annual usage of 50 hours and a 40 percent load fador. Factors for g/hphr can
be used in instances where annual usages, load factors, and rated horsepower are known. Horsepower hours are the product of the
usage in hours, the load factor, and the rated horsepower.
°Values calculated, not measured, based on the use of 0.043 percent sulfur content fuel.
Values calculated from annual fuel consumption. Evaporative losses from storage and filling operations are not included (see
Chapter 4).
3.2.5-2
EMISSION FACTORS
1/75
-------
3.2.6 Agricultural Equipment
by David S. Kircher
3.2.6.1 General - Farm equipment can be separated into two major categories: wheeled tractors and other farm
machinery. In 1972, the wheeled tractor population on farms consisted of 4.5 million units with an average power
of approximately 34 kilowatts (45 horsepower). Approximately 30 percent of the total population of these
tractors is powered by diesel engines. The average diesel tractor is more powerful than the average gasoline tractor,
that is, 52 kW (70 hp) versus 27 kW (36 hp).v A considerable amount of population and usage data is available
for farm tractors. For example, the Census of Agriculture reports the number of tractors in use for each county in
the U.S.2 Few data are available on the usage and numbers of non-tractor farm equipment, however. Self-propelled
combines, forage harvesters, irrigation pumps, and auxiliary engines on pull-type combines and balers are examples
of non-tractor agricultural uses of internal combustion engines. Table 3.2.6-1 presents data on this equipment for
the U.S.
3.2.6.2 Emissions — Emission factors for wheeled tractors and other farm machinery are presented in Table
3.2.6-2. Estimating emissions from the time-based emission factors-grams per hour (g/hr) and pounds per hour
(lb/hr)—requires an average usage value in hours. An approximate figure of 550 hours per year may be used or, on
the basis of power, the relationship, usage in hours = 450 + 5.24 (kW - 37.2) or usage in hours = 450 + 3.89 (hp -
50) may be employed.^
The best emissions estimates result from the use of "brake specific" emission factors (g/kWh or g/hphr).
Emissions are the product of the brake specific emission factor, the usage in hours, the power available, and the
load factor (power used divided by power available). Emissions are also reported in terms of fuel consumed.
Table 3.2.6-1. SERVICE CHARACTERISTICS OF FARM EQUIPMENT
(OTHER THAN TRACTORS)3
Machine
Combine, self-
propelled
Combine, pull
type
Corn pickers
and picker-
shellers
Pick-up balers
Forage
harvesters
Miscellaneous
Units in
service, x1Q3
434
289
687
655
295
1205
Typical
size
4.3m
(14ft)
2.4m
(8ft)
2 -row
5400 kg/hr
(6 ton/hr)
3.7 m
(12ft) or
3-row
-
Typical power
kW
82
19
_b
30
104
22
hp
110
25
40
140
30
Percent
gasoline
50
100
100
0
50
Percent
diesel
50
0
0
100
50
Reference 1.
Unpowered.
1/75
Internal Combustion Engine Sources
3.2.6-1
-------
Table 3.2.6-2. EMISSION FACTORS FOR WHEELED FARM TRACTORS AND
NON-TRACTOR AGRICULTURAL EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust
hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Crankcase
hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Evaporative
hydrocarbons"
g/unit-year
Ib/unit-year
Nitrogen oxides
(NOxasN02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides0
(SOxasS02)
g/hr
Ib/hr
Diesel farm
tractor
161
0.355
4.48
3.34
14.3
119
77.8
0.172
2.28
1.70
7.28
60.7
—
_
-
—
—
-
-
—
452
0.996
12.6
9.39
40.2
335
16.3
0.036
0.456
0.340
1.45
12.1
42.2
0.093
Gasoline farm
tractor
3,380
7.46
192
143
391
3,260
128
0.282
7.36
5.49
15.0
125
26.0
0.057
1.47
1.10
3.01
25.1
15,600
34.4
157
0.346
8.88
6.62
18.1
151
7.07
0.016
0.402
0.300
0.821
6.84
5.56
0.012
Diesel farm
equipment
(non-tractor)
95.2
0.210
5.47
4.08
16.7
139
38.6
0.085
2.25
1.68
6.85
57.1
._
—
-
„
__
—
-
-
210
0.463
12.11
9.03
36.8
307
7.23
0.016
0.402
0.30
1.22
10.2
21.7
0.048
Gasoline farm
equipment
(non-tractor)
4,360
9.62
292
218
492
4,100
143
0.315
9.63
7.18
16.2
135
28.6
0.063
1.93
1.44
3.25
27.1
1,600
3.53
105
0.231
7.03
5.24
11.8
98.5
4.76
0.010
0.295
0.220
0.497
4.14
6.34
0.014
3.2.6-2
EMISSION FACTORS
1/75
-------
Table 3.2.6-2. (continued). EMISSION FACTORS FOR WHEELED FARM TRACTORS AND
NON-TRACTOR AGRICULTURAL EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Paniculate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Diesel farm
tractor
1.17
0.874
3.74
31.2
61.8
0.136
1.72
1.28
5.48
45.7
Gasoline farm
tractor
0.312
0.233
0.637
5.31
8.33
0.018
0.471
0.361
0.960
8.00
Diesel farm
equipment
(non-tractor)
1.23
0.916
3.73
31.1
34.9
0.077
2.02
1.51
6.16
51.3
Gasoline farm
equipment
(non-tractor)
0.377
0.281
0.634
5.28
7.94
0.017
0.489
0.365
0.823
6.86
Reference 1.
Crankcase and evaporative emissions from diesel engines are considered negligible.
Not measured. Calculated from fuel sulfur content of 0.043 percent and 0.22 percent for gasoline-powered and diesel-
powered equipment, respectively.
References for Section 3.2.6
1. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report. Part 5: Heavy-Duty Farm, Construction and Industrial Engines.
Southwest Research Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. EHS 70-108. August 1973. 97 p.
2. County Farm Reports. U.S. Census of Agriculture. U.S. Department of Agriculture. Washington, D.C.
1/75
Internal Combustion Engine Sources
3.2.6-3
-------
-------
3.2.7 Heavy-Duty Construction Equipment by David S. Kircher
3.2.7.1 General — Because few sales, population, or usage data are available for construction equipment, a number
of assumptions were necessary in formulating the emission factors presented in this section.1 The useful life of
construction equipment is fairly short because of the frequent and severe usage it must endure. The annual usage of
the various categories of equipment considered here ranges from 740 hours (wheeled tractors and rollers) to 2000
hours (scrapers and off-highway trucks). This high level of use results in average vehicle lifetimes of only 6 to 16
years. The equipment categories in this section include: tracklaying tractors, tracklaying shovel loaders, motor
graders, scrapers, off-highway trucks, wheeled loaders, wheeled tractors, rollers, wheeled dozers, and miscellaneous
machines. The latter category contains a vast array of less numerous mobile and semi-mobile machines used in
construction, such as, belt loaders, cranes, pumps, mixers, and generators. With the exception of rollers, the
majority of the equipment within each category is diesel-powered.
3.2.7.2 Emissions - Emission factors for heavy-duty construction equipment are reported in Table 3.2.7-1 for
diesel engines and in Table 3.2.7-2 for gasoline engines. The factors are reported in three different forms-on the
basis of running time, fuel consumed, and power consumed. In order to estimate emissions from time-based
emission factors, annual equipment usage in hours must be estimated. The following estimates of use for the
equipment listed in the tables should permit reasonable emission calculations.
Category
Tracklaying tractors
Tracklaying shovel loaders
Motor graders
Scrapers
Off-highway trucks
Wheeled loaders
Wheeled tractors
Rollers
Wheeled dozers
Miscellaneous
Annual operation, hours/year
1050
1100
830
2000
2000
1140
740
740
2000
1000
The best method for calculating emissions, however, is on the basis of "brake specific" emission factors (g/kWh
or g/hphr). Emissions are calculated by taking the product of the brake specific emission factor, the usage in hours,
the power available (that is, rated power), and the load factor (the power actually used divided by the power
available).
References for Section 3.2.7
1. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines - Final Report. Part 5: Heavy-Duty Farm, Construction, and Industrial Engines.
Southwest Research Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. EHS 70-108. October 1973. 105 p.
2. Hare, C. T. Letter to C. C. Masser of Environmental Protection Agency, Research Triangle Park, N.C.,
concerning fuel-based emission rates for farm, construction, and industrial engines. San Antonio, Tex. January
14, 1974. 4 p.
1/75 Internal Combustion Engine Sources 3.2.7-1
-------
Table 3.2.7-1. EMISSION FACTORS FOR HEAVY-DUTY, DIESEL-POWERED CONSTRUCTION
EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Nitrogen oxides
(NOxaslMO2)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
(SO as S02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Tracklaying
tractor
175.
0.386
3.21
2.39
10.5
87.5
50.1
0.110
0.919
0.685
3.01
25.1
665.
1.47
12.2
9.08
39.8
332.
12.4
0.027
0.228
0.170
0.745
6.22
62.3
0.137
1.14
0.851
3.73
31.1
50.7
0.112
0.928
0.692
3.03
25.3
Wheeled
tractor
973.
2.15
5.90
4.40
19.3
161.
67.2
0.148
1.86
1.39
6.10
50.9
451.
0.994
12.5
9.35
41.0
342.
13.5
0.030
0.378
0.282
1.23
10.3
40.9
0.090
1.14
0.851
3.73
31.1
61.5
0.136
1.70
1.27
5.57
46.5
Wheeled
dozer
335.
0.739
2.45
1.83
7.90
65.9
106.
0.234
0.772
0.576
2.48
20.7
2290.
5.05
16.8
12.5
53.9
450.
29.5
0.065
0.215
0.160
0.690
5.76
158.
0.348
1.16
0.867
3.74
31.2
75.
0.165
0.551
0.411
1.77
14.8
Scraper
660.
1.46
3.81
2.84
11.8
98.3
284.
0.626
1.64
1.22
5.06
42.2
2820.
6.22
16.2
12.1
50.2
419.
65.
0.143
0.375
0.280
1.16
9.69
210.
0.463
1.21
0.901
3.74
31.2
184.
0.406
1.06
0.789
3.27
27.3
Motor
grader
97.7
0.215
2.94
2.19
. 9.35
78.0
24.7
0.054
0.656
0.489
2.09
17.4
478.
1.05
14.1
10.5
44.8
374.
5.54
0.012
0.162
0.121
0.517
4.31
39.0
0.086
1.17
0.874
3.73
31.1
27.7
0.061
0.838
0.625
2.66
22.2
References 1 and 2.
3.2.7-2
EMISSION FACTORS
1/75
-------
Table 3.2.7-1 (continued). EMISSION FACTORS FOR HEAVY-DUTY, DIESEL-POWERED
CONSTRUCTION EQUIPMENTS
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Nitrogen oxides
(NOX as N02>
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
(SOxasSO2>
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Wheeled
loader
251.
0.553
3.51
2.62
11.4
95.4
84.7
0.187
1.19
0.888
3.87
32.3
1090.
2.40
15.0
11.2
48.9
408.
18.8
0.041
0.264
0.197
0.859
7.17
82.5
0.182
1.15
0.857
3.74
31.2
77.9
0.172
1.08
0.805
3.51
29.3
Tracklaying
loader
72.5
0.160
2.41
1.80
7.90
65.9
14.5
0.032
0.485
0.362
1.58
13.2
265.
0.584
8.80
6.56
28.8
240.
4.00
0.009
0.134
0.100
0.439
3.66
34.4
0.076
1.14
0.853
3.74
31.2
26.4
0.058
0.878
0.655
2.88
24.0
Off-
Highway
truck
610.
1.34
3.51
2.62
11.0
92.2
198.
0.437
1.14
0.853
3.60
30.0
3460.
7.63
20.0
14.9
62.8
524.
51.0
0.112
0.295
0.220
0.928
7.74
206.
0.454
1.19
0.887
3.74
31.2
116.
0.256
0.673
0.502
2.12
17.7
Roller
83.5
0.184
4.89
3.65
13.7
114.
24.7
0.054
1.05
0.781
2.91
24.3
474.
1.04
21.1
15.7
58.5
488.
7.43
0.016
0.263
0.196
0.731
6.10
30.5
0.067
1.34
1.00
3.73
31.1
22.7
0.050
1.04
0.778
2.90
24.2
Miscel-
laneous
188.
0.414
3.78
2.82
11.3
94.2
71.4
0.157
1.39
1.04
4.16
34.7
1030.
2.27
19.8
14.8
59.2
494.
13.9
0.031
0.272
0.203
0.813
6.78
64.7
0.143
1.25
0.932
3.73
31.1
63.2
0.139
1.21
0.902
3.61
30.1
References 1 and 2.
1/75
Internal Combustion Engine Sources
3.2.7-3
-------
Table 3.2.7-2. EMISSION FACTORS FOR HEAVY-DUTY GASOLINE-POWERED
CONSTRUCTION EQUIPMENT®
EMISSION FACTOR RATING: C
Pollutant
Carbon monoxide
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Evaporative
hydrocarbons'3
g/hr
Ib/hr
Crankcase
hydrocarbons'3
g/hr
Ib/hr
Nitrogen oxides
(NOX as N02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
(RCHOasHCHO)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
(SOX as S02)
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Wheeled
tractor
4320.
9.52
190.
142.
389.
3250.
164.
0.362
7.16
5.34
14.6
122.
30.9
0.0681
32.6
0.0719
195.
0.430
8.54
6.37
17.5
146.
7.97
0.0176
0.341
0.254
0.697
5.82
7.03
0.0155
0.304
0.227
0.623
5.20
Motor
grader
5490.
12.1
251.
187.
469.
3910.
186.
0.410
8.48
6.32
15.8
132.
30.0
0.0661
37.1
0.0818
145.
0.320
6.57
4.90
12.2
102.
8.80
0.0194
0.386
0.288
0.721
6.02
7.59
0.0167
0.341
0.254
0.636
5.31
Wheeled
loader
7060.
15.6
219.
163.
435.
3630.
241.
0.531
7.46
5.56
14.9
124.
29.7
0.0655
48.2
0.106
235.
0.518
7.27
5.42
14.5
121.
9.65
0.0213
0.298
0.222
0.593
4.95
10.6
0.0234
0.319
0.238
0.636
5.31
Rolfer
6080.
13.4
271.
202.
460.
3840.
277.
0.611
12.40
9.25
21.1
176.
28.2
0.0622
55.5
0.122
164.
0.362
7.08
528
12.0
100.
7.57
0.0167
0.343
0.256
0.582
4.86
8.38
0.0185
0.373
0.278
0.633
5.28
Miscel-
laneous
7720.
17.0
266.
198.
475.
3960.
254.
0.560
8.70
6.49
15.6
130.
25.4
0.0560
50.7
0.112
187.
0.412
6.42
4.79
11.5
95.8
9.00
0.0198
0.298
0.222
0.532
4.44
10.6
0.0234
0.354
0.264
0.633
5.28
3.2.7-4
EMISSION FACTORS
1/75
-------
Table 3.2.7-2. (continued). EMISSION FACTORS FOR HEAVY-DUTY GASOLINE-POWERED
CONSTRUCTION EQUIPMENT3
EMISSION FACTOR RATING: C
Pollutant
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Wheeled
tractor
10.9
0.0240
0.484
0.361
0.991
8.27
Motor
grader
9.40
0.0207
0.440
0.328
0.822
6.86
Wheeled
loader
13.5
0.0298
0.421
0.314
0.839
7.00
Roller
11.8
0.0260
0.527
0.393
0.895
7.47
Miscel-
laneous
11.7
0.0258
0.406
0.303
0.726
6.06
a,
References 1 and 2.
""Evaporative and crankcase hydrocarbons based on operating time only (Reference 1).
1/75
Internal Combustion Engine Sources
3.2.7-5
-------
-------
3.2.8 Snowmobiles by Charles C. Masser
3.2,8.1 General — In order to develop emission factors for snowmobiles, mass emission rates must be known, and
operating cycles representative of usage in the field must be either known or assumed. Extending the applicability
of data from tests of a few vehicles to the total snowmobile population requires additional information on the
composition of the vehicle population by engine size and type. In addition, data on annual usage and total machine
population are necessary when the effect of this source on national emission levels is estimated.
An accurate determination of the number of snowmobiles in use is quite easily obtained because most states
require registration of the vehicles. The most notable features of these registration data are that almost 1.5 million
sleds are operated in the United States, that more than 70 percent of the snowmobiles are registered in just four
states (Michigan, Minnesota, Wisconsin, and New York), and that only about 12 percent of all snowmobiles are
found in areas outside the northeast and northern midwest.
3.2.8.2 Emissions — Operating data on snowmobiles are somewhat limited, but enough are available so that an
attempt can be made to construct a representative operating cycle. The required end products of this effort are
time-based weighting factors for the speed/load conditions at which the test engines were operated; use of these
factors will permit computation of "cycle composite" mass emissions, power consumption, fuel consumption, and
specific pollutant emissions.
Emission factors for snowmobiles were obtained through an EPA-contracted study ^ in which a variety of
snowmobile engines were tested to obtain exhaust emissions data. These emissions data along with annual usage
data were used by the contractor to estimate emission factors and the nationwide emission impact of this pollutant
source.
To arrive at average emission factors for snowmobiles, a leasonable estimate of average engine size was
necessary. Weighting the size of the engine to the degree to which each engine is assumed to be representative of
the total population of engines in service resulted in an estimated average displacement of 362 cubic centimeters
(cm3).
The speed/load conditions at which the test engines were operated represented, as closely as possible, the
normal operation of snowmobiles in the field. Calculations using the fuel consumption data obtained during the
tests and the previously approximated average displacement of 362 cm3 resulted in an estimated average fuel
consumption of 0.94 gal/hr.
To compute snowmobile emission factors on a gram per unit year basis, it is necessary to know not only the
emission factors but also the annual operating time. Estimates of this usage are discussed in Reference 1. On a
national basis, however, average snowmobile usage can be assumed to be 60 hours per year. Emission factors for
snowmobiles are presented in Table 3.2.8-1.
References for Section 3.2.8
1. Hare, C. T. and K. J. Springer. Study of Exhaust Emissions from Uncontrolled Vehicles and Related
Equipment Using Internal Combustion Engines. Final Report. Part 7: Snowmobiles. Southwest Research
Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research Triangle Park, N.C.,
under Contract No. EHS 70-108. April 1974.
1/75 Internal Combustion Engine Sources 3.2.8-1
-------
Table 3.2.8-1. EMISSION FACTORS FOR
SNOWMOBILES
EMISSION FACTOR RATING: B
Pollutant
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Sulfur oxides0
Solid particulate
Aldehydes (RCHO)
Emissions
g/unit-yeara
58,700
37,800
600
51
1,670
552
g/gaib
1,040.
670.
10.6
0.90
29.7
9.8
g/literb
275.
177.
2.8
0.24
7.85
2.6
g/hrb
978.
630.
10.0
0.85
27.9
£1.2
3 "%
Based on 60 hours of operation per year and 362 cm displacement.
Based on 362 cm displacement and average fuel consumption of 0,94 gal/hr.
°Based on sulfur content of 0.043 percent by weight.
3.2.8-2
EMISSION FACTORS
1/75
-------
3.3 OFF-HIGHWAY, STATIONARY SOURCES by David S. Kircher and
Charles C. Masser
In general, engines included in this category are internal combustion engines used in applications similar to those
associated with external combustion sources (see Chapter 1). The major engines within this category are gas
turbines and large, heavy-duty, general utility reciprocating engines. Emission data currently available for these
engines are limited to gas turbines and natural-gas-fired, heavy-duty, general utility engines. Most stationary
internal combustion engines are used to generate electric power, to pump gas or other fluids, or to compress air for
pneumatic machinery.
3.3.1 Stationary Gas Turbines for Electric Utility Power Plants
3.3.1.1 General - Stationary gas turbines find application in electric power generators, in gas pipeline pump and
compressor drives, and in various process industries. The majority of these engines are used in electrical generation
for continuous, peaking, or standby power.l The primary fuels used are natural gas and No. 2 (distillate) fuel oil,
although residual oil is used in a few applications.
3.3.1.2 Emissions - Data on gas turbines were gathered and summarized under an EPA contract.2 The contractor
found that several investigators had reported data on emissions from gas turbines used in electrical generation but
that little agreement existed among the investigators regarding the terms in which the emissions were expressed.
The efforts represented by this section include acquisition of the data and their conversion to uniform terms.
Because many sets of measurements reported by the contractor were not complete, this conversion often involved
assumptions on engine air flow or fuel flow rates (based on manufacturers' data). Another shortcoming of the
available information was that relatively few data were obtained at loads below maximum rated (or base) load.
Available data on the population and usage of gas turbines in electric utility power plants are fairly extensive,
and information from the various sources appears to be in substantial agreement. The source providing the most
complete information is the Federal Power Commission, which requires major utilities (electric revenues of $1
million or more) to submit operating and financial data on an annual basis. Sawyer and Farmer^ employed these
data to develop statistics on the use of gas turbines for electric generation in 1971. Although their report involved
only the major, publicly owned utilities (not the private or investor-owned companies), the statistics do appear to
include about 87 percent of the gas turbine power used for electric generation in 1971.
Of the 253 generating stations listed by Sawyer and Farmer, 137 have more than one turbine-generator unit.
From the available data, it is not possible to know how many hours each turbine was operated during 1971 for
these multiple-turbine plants. The remaining 116 (single-turbine) units, however, were operated an average of 1196
hours during 1971 (or 13.7 percent of the time), and their average load factor (percent of rated load) during
operation was 86.8 percent. This information alone is not adequate for determining a representative operating
pattern for electric utility turbines, but it should help prevent serious errors.
Using 1196 hours of operation per year and 250 starts per year as normal, the resulting average operating day is
about 4.8 hours long. One hour of no-load time per day would represent about 21 percent of operating time, which
is considered somewhat excessive. For economy considerations, turbines are not run at off-design conditions any
longer than necessary, so time spent at intermediate power points is probably minimal. The bulk of turbine
operation must be at base or peak load to achieve the high load factor already mentioned.
If it is assumed that time spent at off-design conditions includes 15 percent at zero load and 2 percent each at
25 percent, 50 percent, and 75 percent load, then the percentages of operating time at rated load (100 percent)
and peak load (assumed to be 125 percent of rated) can be calculated to produce an 86.8 percent load factor.
These percentages turn out to be 19 percent at peak load and 60 percent at rated load; the postulated cycle based
on this line of reasoning is summarized in Table 3.3.1-1.
1/75 Internal Combustion Engine Sources 3.3.1-1
-------
Table 3.3.1-1. TYPICAL OPERATING CYCLE FOR ELECTRIC
UTILITY TURBINES
Condition,
% of rated
power
0
25
50
75
100 (base)
125 (peak)
Percent operating
time spent
at condition
15
2
2
2
60
19
Time at condition
based on 4.8-hr day
hours
0.72
0.10
0.10
0.10
2.88
0.91
4.81
minutes
43
6
6
6
173
55
289
Contribution to load
factor at condition
0.00x0.15 = 0.0
0.25 x 0.02 = 0.005
0.50x0.02 = 0.010
0.75x0.02 = 0.015
1.0 x 0.60 = 0.60
1.25x0.19 = 0.238
Load factor = 0.868
The operating cycle in Table 3.3.1-1 is used to compute emission factors, although it is only an estimate of actual
operating patterns.
Table 3.3.1-2. COMPOSITE EMISSION FACTORS FOR 1971
POPULATION OF ELECTRIC UTILITY TURBINES
EMISSION FACTOR RATING: B
Time basis
Entire population
Ib/hr rated load3
kg/hr rated load
Gas-fired only
Ib/hr rated load
kg/hr rated load
Oil-fired only
Ib/hr rated load
kg/hr rated load
Fuel basis
Gas- fired only
Ib/106ft3gas
kg/106m3 gas
Oil-fired only
lb/103galoil
kg/103 liter oil
Nitrogen
oxides
8.84
4.01
7.81
3.54
9.60
4.35
413.
6615.
67.8
8.13
Hydro-
carbons
0.79
0.36
0.79
0.36
0.79
0.36
42.
673.
5.57
0.668
Carbon
Monoxide
2.18
0.99
2.18
0.99
2.18
0.99
115.
1842.
15.4
1.85
Panic-
ulate
0.52
0.24
0.27
0.12
0.71
0.32
14.
224.
5.0
0.60
Sulfur
oxides
0.33
0.15
0.098
0.044
0.50
0.23
5.2
83.
3.5
0.42
Rated load expressed in megawatts.
Table 3.3.1-2 is the resultant composite emission factors based on the operating cycle of Table 3.3.1-1 and the
1971 population of electric utility turbines".
3.3.1-2
EMISSION FACTORS
1/75
-------
Different values for time at base and peak loads are obtained by changing the total time at lower loads (0
through 75 percent) or by changing the distribution of time spent at lower loads. The cycle given in Table 3.3.1-1
seems reasonable, however, considering the fixed load factor and the economies of turbine operation. Note that the
cycle determines only the importance of each load condition in computing composite emission factors for each
type of turbine, not overall operating hours.
The top portion of Table 3.3.1-2 gives separate factors for gas-fired and oil-fired units, and the bottom portion
gives fuel-based factors that can be used to estimate emission rates when overall fuel consumption data are
available. Fuel-based emission factors on a mode basis would also be useful but present fuel consumption data are
not adequate for this purpose.
References for Section 3.3.1
1. O'Keefe, W. and R. G. Schwieger. Prime Movers. Power. 115(\ 1): 522-531. November 1971.
2. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report. Part 6: Gas Turbine Electric Utility Power Plants. Southwest
Research Institute, San Antonio, Tex. Prepared for Environmental Protection Agency, Research Triangle Park,
N.C., under Contract No. EHS 70-108, February 1974.
3. Sawyer, V. W. and R. C. Farmer. Gas Turbines in U.S. Electric Utilities. Gas Turbine International. January —
April 1973.
1/75 Internal Combustion Engine Sources 3.3.1-3
-------
-------
3.3.2 Heavy-Duty, Natural-Gas-Fired Pipeline Compressor Engines by Susan Sercer
Alan Burgess
Tom Lahre
3.3.2.1 General1 - Engines in the natural gas industry are used primarily to power compressors used for pipeline
transportation, field gathering (collecting gas from wells), underground storage, and gas processing plant
applications. Pipeline engines are concentrated in the major gas producing states (such as those along the Gulf
Coast) and along the major gas pipelines. Both reciprocating engines and gas turbines are utilized, but the trend
has been toward use of large gas turbines. Gas turbines emit considerably fewer pollutants than do reciprocating
engines; however, reciprocating engines are generally more efficient in their use of fuel.
3.3.2.2 Emissions and Controls1 '2 - The primary pollutant of concern is NOX, which readily forms in the high
temperature, pressure, and excess air environment found in natural-gas-fired compressor engines. Lesser amounts
of carbon monoxide and hydrocarbons are emitted, although for each unit of natural gas burned, compressor
engines (particularly reciprocating engines) emit significantly more of these pollutants than do external
combustion boilers. Sulfur oxides emissions are proportional to the sulfur content of the fuel and will usually be
quite low because of the negligible sulfur content of most pipeline gas.
The major variables affecting NOX emissions from compressor engines include the air fuel ratio, engine load
(defined as the ratio of the operating horsepower divided by the rated horsepower), intake (manifold) air
temperature, and absolute humidity. In general, NOX emissions increase with increasing load and intake air
temperature and decrease with increasing absolute humidity and air fuel ratio. (The latter already being, in most
compressor engines, on the "lean" side of that air fuel ratio at which maximum NOX formation occurs.)
Quantitative estimates of the effects of these variables are presented in Reference 2.
Because NOX is the primary pollutant of significance emitted from pipeline compressor engines, control
measures to date have been directed mainly at limiting NOX emissions. For gas turbines, the most effective
method of controlling NOX emissions is the injection of water into the combustion chamber. Nitrogen oxides
reductions as high as 80 percent can be achieved by this method. Moreover, water injection results in only
nominal reductions in overall turbine efficiency. Steam injection can also be employed, but the resulting NOX
reductions may not be as great as with water injection, and it has the added disadvantage that a supply of steam
must be readily available. Exhaust gas recirculation, wherein a portion of the exhaust gases is recirculated back
into the intake manifold, may result in NOX reductions of up to 50 percent. This technique, however, may not be
practical in many cases because the recirculated gases must be cooled to prevent engine malfunction. Other
combustion modifications, designed to reduce the temperature and/or residence time of the combustion gases,
can also be effective in reducing NOX emissions by 10 to 40 percent in specific gas turbine units.
For reciprocating gas-fired engines, the most effective NOX control measures are those that change the air-fuel
ratio. Thus, changes in engine torque, speed, intake air temperature, etc., that in turn increase the air-fuel ratio,
may all result in lower NOX emissions. Exhaust gas recirculation may also be effective in lowering NOX emissions
although, as with turbines, there are practical limits because of the large quantities of exhaust gas that must be
cooled. Available data suggest that other NOX control measures, including water and steam injection, have only
limited application to reciprocating gas-fired engines.
Emission factors for natural-gas-fired pipeline compressor engines are presented in Table 3.3.2-1.
4/76 Internal Combustion Engine Sources 3.3.2-1
-------
Table 3.3.2-1. EMISSION FACTORS FOR HEAVY-DUTY, NATURAL-
GAS-FIRED PIPELINE COMPRESSOR ENGINES3
EMISSION FACTOR RATING: A
Reciprocating engines
lb/103hp-hr
g/hp-hr
g/kW-hr
lb/106scff
kg/106Nm3f
Gas turbines
lb/103hp-hr
g/hp-hr
g/kW-hr
Ib/106scf9
kg/106Nm39
Nitrogen oxides
-------
3.3.3 Gasoline and Diesel Industrial Engines
by David S. Kircher
3.3.3-1 General - This engine category covers a wide variety of industrial applications of both gasoline and diesel
internal combustion power plants, such as fork lift trucks, mobile refrigeration units, generators, pumps, and
portable well-drilling equipment. The rated power of these engines covers a rather substantial range—from less than
15 kW to 186 kW (20 to 250 hp) for gasoline engines and from 34 kW to 447 kW (45 to 600 hp) for diesel engines.
Understandably, substantial differences in both annual usage (hours per year) and engine duty cycles also exist. It
was necessary, therefore, to make reasonable assumptions concerning usage in order to formulate emission
factors.1
3.3.3-2 Emissions - Once reasonable usage and duty cycles for this category were ascertained, emission values
from each of the test engines l were aggregated (on the basis of nationwide engine population statistics) to arrive at
the factors presented in Table 3.3.3-1. Because of their aggregate nature, data contained in this table must be
applied to a population of industrial engines rather than to an individual power plant.
The best method for calculating emissions is on the basis of "brake specific" emission factors (g/kWh or
Ib/hphr). Emissions are calculated by taking the product of the brake specific emission factor, the usage in hours
(that is, hours per year or hours per day), the power available (rated power), and the load factor (the power
actually used divided by the power available).
Table 3.3.3-1. EMISSION FACTORS FOR GASOLINE-
AND DIESEL-POWERED INDUSTRIAL EQUIPMENT
EMISSION FACTOR RATING: C
Pollutant3
Carbon monoxide
9/br
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Exhaust hydrocarbons
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Evaporative hydrocarbons
g/hr
Ib/hr
Crankcase hydrocarbons
g/hr
Ib/hr
Engine category
Gasoline
5700.
12.6
267.
199.
472.
3940.
191.
0.421
8.95
6.68
15.8
132.
62.0
0.137
38.3
0.084
Diesel
197.
0.434
4.06
3.03
12.2
102.
72.8
0.160
1.50
1.12
4.49
37.5
-
_
1/75
Internal Combustion Engine Sources
3.3.3-1
-------
Table 3.3.3-1. (continued). EMISSION FACTORS FOR GASOLINE-
AND DIESEL-POWERED INDUSTRIAL EQUIPMENT
EMISSION FACTOR RATING: C
Pollutant3
Nitrogen oxides
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Aldehydes
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Sulfur oxides
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Particulate
g/hr
Ib/hr
g/kWh
g/hphr
kg/103 liter
lb/103 gal
Engine category"
Gasoline
148.
0.326
6.92
5.16
12.2
102.
6.33
0.014
0.30
0.22
0.522
4.36
7.67
0.017
0.359
0.268
0.636
5.31
9.33
0.021
0.439
0.327
0.775
6.47
Diesel
910.
2.01
18.8
14.0
56.2
469.
13.7
0.030
0.28
0.21
0.84
7.04
60.5
0.133
1.25
0.931
3.74
31.2
65.0
0.143
1.34
1.00
4.01
33.5
References 1 and 2.
As discussed in the text, the engines used to determine the results in this
table cover a wide range of uses and power. The listed values do not,
however, necessarily apply to some very large stationary diesel engines.
References for Section 3.3.3
1. Hare, C. T. and K. J. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Internal Combustion Engines. Final Report. Part 5: Heavy-Duty Farm, Construction, and Industrial Engines.
Southwest Research Institute. San Antonio, Texas. Prepared for Environmental Protection Agency, Research
Triangle Park, N.C., under Contract No. EHS 70-108. October 1973. 105 p.
2. Hare, C. T. Letter to C. C. Masser of the Environmental Protection Agency concerning fuel-based emission
rates for farm, construction, and industrial engines. San Antonio, Tex. January 14, 1974.
3.3.3-2
EMISSION FACTORS
1/75
-------
4. EVAPORATION LOSS SOURCES
Evaporation losses include the organic solvents emitted from dry-cleaning plants and surface-
coating operations as well as the volatile matter in petroleum products. This chapter presents the
hydrocarbon emissions from these sources, including liquid petroleum storage and marketing. Where
possible, the effect of controls to reduce the emissions of organic compounds has been shown.
4.1 DRY CLEANING by Susan Sercer
4.1.1 General1'2
Dry cleaning involves the cleaning of fabrics with non-aqueous organic solvents. The dry cleaning
process requires three steps: (1) washing the fabric in solvent, (2) spinning to extract excess solvent, and
(3) drying by tumbling in a hot airstream.
Two general types of cleaning fluids are used in the industry: petroleum solvents and synthetic sol-
vents. Petroleum solvents, such as Stoddard or 140-F, are inexpensive, combustible hydrocarbon
mixtures similar to kerosene. Operations using petroleum solvents are known as petroleum plants.
Synthetic solvents are nonflammable but more expensive halogenated hydrocarbons. Perchloro-
ethylene and trichlorotrifluoroethane are the two synthetic dry cleaning solvents presently in
use. Operations using these synthetic solvents are called "perc" plants and fluorocarbon plants,
respectively.
There are two basic types of dry cleaning machines: transfer and dry-to-dry. Transfer machines ac-
complish washing and drying in separate machines. Usually the washer extracts excess solvent from the
clothes before they are transferred to the dryer, however, some older petroleum plants have separate
extractors for this purpose. Dry-to-dry machines are single units that perform all of the washing,
extraction, and drying operations. All petroleum solvent machines are the transfer type, but synthetic
solvent plants can be either type.
The dry cleaning industry can be divided into three sectors: coin-operated facilities, commercial
operations, and industrial cleaners. Coin-operated facilities are usually part of a laundry and supply
"self-service" type dry cleaning for consumers. Only synthetic solvents are used in coin-operated dry
cleaning machines. Such machines are small, with a capacity of 8 to 25 Ib (3.6 to 11.5 kg) of clothing.
Commercial operations, such as small neighborhood or franchise dry cleaning shops, clean soiled
apparel for the consumer. Generally, perchloroethylene and petroleum solvents are used in commer-
cial operations. A typical "perc" plant operates a 30 to 60 Ib (14 to 27 kg) capacity washer/extractor and
an equivalent size reclaiming dryer.
Industrial cleaners are larger dry cleaning plants which supply rental service of uniforms, mats,
mops, etc., to businesses or industries. Although petroleum solvents are used extensively, perchloro-
ethylene is used by approximately 50% of the industrial dry cleaning establishments. A typical large in-
dustrial cleaner has a 500 Ib (230 kg) capacity washer/ extractor and three to six 100 Ib (38 kg) capacity
dryers.
A typical perc plant is shown in Figure 4.1-1. Although one solvent tank may be used, the typical
perc plant uses two tanks for washing. One tank contains pure solvent; the other tank contains
"charged" solvent — used solvent to which small amounts of detergent have been added to aid in clean-
ing. Generally, clothes are cleaned in charged solvent and rinsed in pure solvent. A water bath may also
be used.
4/77 Evaporative Loss Sources 4.1-1
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EMISSION FACTORS
4/77
-------
After the clothes have been washed, the used solvent is filtered, and part of the filtered solvent is re-
turned to the charged solvent tank for washing the next load. The remaining solvent is then distilled to
remove oils, fats, greases, etc., and returned to the pure solvent tank. The resulting distillation'bot-
toms are typically stored on the premises until disposed of. The filter cake and collected solids (muck)
are usually removed from the filter once a day. Before disposal, the muck may be "cooked" to recover
additional solvent. Still and muck cooker vapors are vented to a condenser and separator where more
solvent is reclaimed. In many perc plants, the condenser off-gases are vented to a carbon adsorption
unit for additional solvent recovery.
After washing, the clothes are transferred to the dryer where they are tumbled in a heated air-
stream. Exhaust gases from the dryer, along with a small amount of exhaust gases from the washer/ex-
tractor, are vented to a water-cooled condenser and water separator. Recovered solvent is returned to
the pure solvent storage tank. In 30-50 percent of the perc plants, the condenser off-gases are vented to
a carbon adsorption unit for additional solvent recovery. To reclaim this solvent, the unit must be
periodically desorbed with steam—typically at the end of each day. Desorbed solvent and water are
condensed and separated; recovered solvent is returned to the pure solvent tank.
A petroleum plant would differ from Figure 4.1-1 chiefly in that there would be no recovery of sol-
vent from the washer and dryer and no muck cooker. A fluorocarbon plant would differ in that a non-
vented refrigeration system would be used in place of a carbon adsorption unit. Another difference
would be that a typical fluorocarbon plant would use a cartridge filter which is drained and disposed
of after several hundred cycles.
Emissions and Controls1"2'3
The solvent material itself is the primary emission of concern from dry cleaning operations. Sol-
vent is given off by the washer, dryer, solvent still, muck cooker, still residue and filter muck storage
areas, as well as leaky pipes, flanges, and pumps.
Petroleum plants have generally not employed solvent recovery because of the low cost of petro-
leum solvents and the ^ *e -lazards associated with collecting vapors. Some emission control, however,
can be obtained by mt Plaining all equipment in good condition (e.g., preventing lint accumulation,
preventing solvent leakage, etc.) and by using good operating practices (e.g., not overloading machin-
ery). Both carbon adsorption and incineration appear to be technically feasible controls for petroleum
plants, but costs are high.
Solvent recovery is necessary in perc plants due to the higher cost of perchloroethylene. As shown in
Figure 4.1-1, recovery is effected on the washer, dryer, still, and muck cooker through the use of con-
densers, water/solvent separators, and carbon adsorption units. Periodically (typically once a day), sol-
vent collected in the carbon adsorption unit is desorbed with steam, condensed, separated from the
condensed water, and returned to the pure solvent storage tank. Residual solvent emitted from treat-
ed distillation bottoms and muck is not recovered. As in petroleum plants, good emission control can
be obtained by good housekeeping practices (maintaining all equipment in good condition and using
good operating practices).
All fluorocarbon machines are of the dry-to-dry variety to conserve solvent vapor, and all are closed
systems with built-in solvent recovery. High emissions can occur, however, as a result of poor mainte-
nance and operation of equipment. Refrigeration systems are installed on newer machines to recover
solvent from the washer/dryer exhaust gases.
Emission factors for dry cleaning operations are presented in Table 4.1-1.
4/77 Evaporative Loss Sources 4.1-3
-------
Table 4.1-1. SOLVENT LOSS EMISSION FACTORS FOR DRY CLEANING OPERATIONS
EMISSION FACTOR RATING: B
Solvent type
(Process used)
Petroleum
(transfer process)
Perchloroethylene
(transfer process)
Trichlorotrifluoroethane
(dry-to-dry process)
Source
washer/dryerf
filter disposal
uncooked (drained)
centrifuged
still residue disposal
miscellaneous0
washer/dryer/still/muck cooker
filter disposal
uncooked muck
cooked muck
cartridge filter
still residue disposal
miscellaneous0
washer/dryer/still6
cartridge filter disposal
still residue disposal
miscellaneous0
_ 1
Emission rate3
Typical systems
lb/100lb (kg/1 00 kg)
18
5
2
3
3d
14
1.3
1.1
1.6
1.5
0
1
0.5
1 -3
Well-controlled system
lb/100lb (kg/100 kg)
2b
0.5-1
0.5- 1
1
0.3b
0.5- 1.3
0.5-1.1
0.5-1.6
1
0
1
0.5
1 -3
aUnits are in terms of weight of solvent per weight of clothes cleaned (capacity x loads). Emissions may be estimated on an alternative
basis by determining the amount of solvent consumed. Assuming that all solvent input to dry cleaning operations is eventually
evaporated to the atmosphere, an emission factor of 2000 Ib/ton of solvent consumed can be applied. All emission factors are based
on References 1, 2 and 3.
''Emissions from the washer, dryer, still, and muck cooker are collectively passed through a carbon adsorber.
cMiscellaneous sources include fugitive emissions from flanges, pumps, pipes, storage tanks, fixed losses I for example, opening and
closing the dryer), etc.
^Uncontrolled emissions from the washer, dryer, still, and muck cooker average about 8 lb/100 Ib (8 kg/100 kg). Roughly 15% of
the solvent emitted comes from the washer, 75% from the dryer, and 5% from both the still and the muck cooker.
eEmission factors are based on the typical refrigeration system installed in fluorocarbon plants.
f Different materials in the wash retain varying amounts of solvent (synthetic: 10 kg/100 kg, cotton: 20 kg/100 kg, leather: 40 kg/
100kg).
References for Section 4.1
1. Study to Support New Source Performance Standards for the Dry Cleaning Industry, EPA Con-
tract 68-02-1412, Task Order No. 4, prepared by TRW Inc., Vienna, Virginia, May 7, 1976.
Kleeberg, Charles, EPA, Office of Air Quality Planning and Standards.
2. Standard Support and Environmental Impact Statement for the Dry Cleaning Industry. Dur-
ham, North Carolina. June 28, 1976.
3. Control of Volatile Organic Emissions from Dry Cleaning Operations (Draft Document), Dur-
ham, North Carolina. April 15, 1977.
4.1-4
EMISSION FACTORS
4/77
-------
4.2 SURFACE COATING
4.2.1 Process Description1 >2
Surface-coating operations primarily involve the application of paint, varnish, lacquer, or paint primer for
decorative or protective purposes. This is accomplished by brushing, rolling, spraying, flow coating, and dipping.
Some of the industries involved in surface-coating operations are automobile assemblies, aircraft companies,
container manufacturers, furniture manufacturers, appliance manufacturers, job enamelers, automobile re-
painters, and plastic products manufacturers.
4.2.2 Emissions and Controls3
Emissions of hydrocarbons occur in surface-coating operations because of the evaporation of the paint
vehicles, thinners, and solvents used to facilitate the application of the coatings. The major factor affecting these
emissions is the amount of volatile matter contained in the coating. The volatile portion of most common surface
coatings averages approximately 50 percent, and most, if not all, of this is emitted during the application and
drying of the coating. The compounds released include aliphatic and aromatic hydrocarbons, alcohols, ketones,
esters, alkyl and aryl hydrocarbon solvents, and mineral spirits. Table 4.2-1 presents emission factors for
surface-coating operations.
Control of the gaseous emissions can be accomplished by the use of adsorbers (activated carbon) or
afterburners. The collection efficiency of activated carbon has been reported at 90 percent or greater. Water
curtains or filler pads have little or no effect on escaping solvent vapors; they are widely used, however, to stop
paint particulate emissions.
Table 4.2-1. GASEOUS HYDROCARBON EMISSION
FACTORS FOR SURFACE-COATING APPLICATIONS3
EMISSION FACTOR RATING: B
Type of coating
Paint
Varnish and shellac
Lacquer
Enamel
Primer (zinc chromate)
Emissions'3
Ib/ton
1120
1000
1540
840
1320
kg/MT
560
500
770
420
660
3 Reference 1.
"Reported as undefined hydrocarbons, usually organic solvents, both
aryl and alkyl. Paints weigh 10 to 15 pounds per gallon (1.2 to 1.9
kilograms per liter); varnishes weigh about 7 pounds per gallon
(0.84 kilogram per liter).
2/72 Evaporation Loss Sources 4.2-1
-------
References for Section 4.2
1. Weiss, S.F. Surface Coating Operations. In: Air Pollution Engineering Manual, Danielson, J.A. (ed.). U.S.
DHEW, PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40.
p.387-390.
2. Control Techniques for Hydrocarbon and Organic Gases From Stationary Sources. U.S. DHEW, PHS, EHS,
National Air Pollution Control Administration. Washington, D.C. Publication Number AP-68. October 1969.
Chapter 7.6.
3. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
4.2-2 EMISSION FACTORS 2/72
-------
4.3 STORAGE OF PETROLEUM LIQUIDS1 by Charles C. Master
Fundamentally, the petroleum industry consists of three operations: (1) petroleum production and
transportation, (2) petroleum refining, and (3) transportation and marketing of finished petroleum
products. All three operations require some type of storage for petroleum liquids. Storage tanks for
both crude and finished products can be sources of evaporative emissions. Figure 4.3-1 presents a
schematic of the petroleum industry and its points of emissions from storage operations.
4.3.1 Process Description
Four basic tank designs are used for petroleum storage vessels: fixed roof, floating roof (open type
and covered type), variable vapor space, and pressure (low and high).
4.3.1.1 Fixed Roof Tanks2 - The minimum accepted standard for storage of volatile liquids is the
fixed roof tank (Figure 4.3-2). It is usually the least expensive tank design to construct. Fixed roof tanks
basically consist of a cylindrical steel shell topped by a coned roof having a minimum slope of 3/4
inch in 12 inches. Fixed roof tanks are generally equipped with a pressure/vacuum vent designed to
contain minor vapor volume changes. For large fixed roof tanks, the recommended maximum operat-
ing pressure/vacuum is +0.03 psig/-0.03 psig (+2.1 g/cm2/-2.1 g/cm2).
4.3.1.2 Floating Roof Tanks3 - Floating roof tanks reduce evaporative storage losses by minimizing va-
por spaces. The tank consists of a welded or riveted cylindrical steel wall, equipped with a deck or roof
which is free to float on the surface of the stored liquid. The roof then rises and falls according to the
depth of stored liquid. To ensure that the liquid surface is completely covered, the roof is equipped
with a sliding seal which fits against the tank wall. Sliding seals are also provided at support columns
and at all other points where tank appurtenances pass through the floating roof.
Until recent years, the most commonly used floating roof tank was the conventional open-type
tank. The open-type floating roof tank exposes the roof deck to the weather; provisions must be made
for rain water drainage, snow removal, and sliding seal dirt protection. Floating roof decks are of three
general types: pan, pontoon, and double deck. The pan-type roof consists of a flat metal plate with a
vertical rim and sufficient stiffening braces to maintain rigidity (Figure 4.3-3). The single metal plate
roof in contact with the liquid readily conducts solar heat, resulting in higher vaporization losses than
other floating roof decks. The roof is equipped with automatic vents for pressure and vacuum release.
The pontoon roof is a pan-type floating roof with pontoon sections added to the top of the deck around
the rim. The pontoons are arranged to provide floating stability under heavy loads of water and snow.
Evaporation losses due to solar heating are about the same as for pan-type roofs. Pressure/vacuum
vents are required on pontoon roof tanks. The double deck roof is similar to a pan-type floating roof,
but consists of a hollow double deck covering the entire surface of the roof (Figure 4.3-4). The double
deck adds rigidity, and the dead air space between the upper and lower deck provides significant insu-
lation from solar heating. Pressure/vacuum vents are also required.
The covered-type floating roof tank is essentially a fixed-roof tank with a floating roof deck inside
the tank (Figure 4.3-5). The American Petroleum Institute has designated the term "covered floating"
roof to describe a fixed roof tank with an internal steel pan-type floating roof. The term "internal float-
ing cover" has been chosen by the API to describe internal covers constructed of materials other than
steel. Floating roofs and covers can be installed inside existing fixed roof tanks. The fixed roof protects
the floating roof from the weather, and no provision is necessary for rain or snow removal, or for seal
4/77 Evaporation Loss Sources 4.3-1
-------
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-------
, PRESSURE-VACUUM
VENT
GAUGE HATCH,
MANHOLE
Figure 4.3-2. Fixed roof storage tank.
, ROOF SEAL (METALLIC SHOW
WIATHER 1HIELD-
NOZZLE
Figure 4.3-3. Pan-type floating roof storage tank (metallic seals).
ROOF SEAL
• (NON-METALUC)
WEATHER SHKLD-
NOZZLE
Figure 4.3-4. Double deck floating roof storage tank (non-metallic seals).
4/77
Evaporation Loss Sources
4.3-3
-------
AIR SCOOPS.
NOZZLE
Figure 4.3-5. Covered floating roof storage tank.
protection. Antirotational guides must be provided to maintain roof alignment, and the space be-
tween the fixed and floating roofs must be vented to prevent the possible formation of a flammable
mixture.
4.3.1.3 Variable Vapor Space Tanks4 - Variable vapor space tanks are equipped with expandable
vapor reservoirs to accommodate vapor volume fluctuations attributable to temperature and baro-
metric pressure changes. Although variable vapor space tanks are sometimes used independently, they
are normally connected to the vapor spaces of one or more fixed roof tanks. The two most common
types of variable vapor space tanks are lifter roof tanks and flexible diaphragm tanks.
Lifter roof tanks have a telescoping roof that fits loosely around the outside of the main tank wall.
The space between the roof and the wall is closed by either a wet seal, which consists of a trough filled
with liquid, or a dry seal, which employs a flexible coated fabric in place of the trough (Figure 4.3-6).
-PRESSURE-VACUUM
VtKT
NOZZLE
Figure 4.3-6. Lifter roof storage tank (wet seal).
Flexible diaphragm tanks utilize flexible membranes to provide the expandable volume. They may
be separate gasholder type units, or integral units mounted atop fixed roof tanks (Figure 4.3-7)..
4.3-4
EMISSION FACTORS
4/77
-------
PRESSURE
VACUUM VENTS
NOZZLE
Figure 4.3-7. Flexible diaphragm tank (integral unit).
4.3.1.4 Pressure Tanks5 - Pressure tanks are designed to withstand relatively large pressure variations
without incurring a loss. They are generally used for storage of high volatility stocks, and they are
constructed in many sizes and shapes, depending on the operating range. The noded spheroid and
noded hemispheroid shapes are generally used as low-pressure tanks (17 to 30 psia or 12 to 21 mg/m2),
while the horizontal cylinder and spheroid shapes are generally used as high-pressure tanks (up to 265
psia or 186 mg/m2).
4.3.2 Emissions and Controls
There are six sources of emissions from petroleum liquids in storage: fixed roof breathing losses,
fixed roof working losses, floating roof standing storage losses, floating roof withdrawal losses, vari-
able vapor space filling losses, and pressure tank losses.6
Fixed roof breathing losses consist of vapor expelled from a tank because of the thermal expansion
of existing vapors, vapor expansion caused by barometric pressure changes, and/or an increase in the
amount of vapor due to added vaporization in the absence of a liquid-level change.
Fixed roof working losses consist of vapor expelled from a tank as a result of filling and emptying
operations. Filling loss is the result of vapor displacement by the input of liquid. Emptying loss is the
expulsion of vapors subsequent to product withdrawal, and is attributable to vapor growth as the new-
ly inhaled air is saturated with hydrocarbons.
Floating roof standing storage losses result from causes other than breathing or changes in liquid
level. The largest potential source of this loss is attributable to an improper fit of the seal and shoe to
the shell, which exposes some liquid surface to the atmosphere. A small amount of vapor may escape
between the flexible membrane seal and the roof.
Floating roof withdrawal losses result from evaporation of stock which wets the tank wall as the
roof descends during emptying operations. This loss is small in comparison to other types of losses.
4/77
Evaporation Loss Sources
4.3-5
-------
Variable vapor space filling losses result when vapor is displaced by the liquid input during filling
operations. Since the variable vapor space tank has an expandable vapor storage capacity, this loss is
not as large as the filling loss associated with fixed roof tanks. Loss o f vapor occurs only when the vapor
storage capacity of the tank is exceeded.
Pressure tank losses occur when the pressure inside the tank exceeds the design pressure of the
tank, which results in relief vent opening. This happens only when the tank is filled improperly, or
when abnormal vapor expansion occurs. These are not regularly occurring events, and pressure tanks
are not a significant source of loss under normal operating conditions.
The total amount of evaporation loss from storage tanks depends upon the rate of loss and the per-
iod of time involved. Factors affecting the rate of loss include:
1. True vapor pressure of the liquid stored.
2. Temperature changes in the tank.
3. Height of the vapor space (tank outage).
4. Tank diameter.
5. Schedule of tank filling and emptying.
6. Mechanical condition of tank and seals.
7. Type of tank and type of paint applied to outer surface.
The American Petroleum Institute has developed empirical formulae, based on field testing, that cor-
relate evaporative losses with the above factors and other specific storage factors.
4.3.2.1 Fixed Roof Tanks2*7 - Fixed roof breathing losses can be estimated from:
LB = 2.21 x 10-4 M [—L_]°-68 D1.73 UPSI ^0.50 F c K (1)
where: Lg = Fixed roof breathing loss (Ib/day).
M = Molecular weight of vapor in storage tank (Ib/lb mole), (see Table 4.3-1).
P = True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9,
or Table 4.3-1.
D = Tank diameter (ft).
H = Average vapor space height, including roof volume correction ('ft); see note (1).
AT = Average ambient temperature change from day to night (°F).
Fp = Paint factor (dimensionless); see Table 4.3-2.
C = Adjustment factor for small diameter tanks (dimensionless); see Figure 4.3-10.
KC = Crude oil factor (dimensionless); see note (2).
Note: (1) The vapor space in a cone roof is equivalent in volume to a cylinder which has the
same base diameter as the cone and is one-third the height of the cone.
(2) Kc = (0.65) for crude oil, Kc = (1.0) for gasoline and all other liquids.
API reports that calculated breathing loss from Equation (1) may deviate in the order of + 10 percent
from actual breathing loss.
4.3-6 EMISSION FACTORS 4/77
-------
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4/77
Evaporation Loss Sources
4.3-7
-------
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10 PER CENT EVAPORATED »
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10
IN THE ABSENCE OF DISTILLATION DATA THE
ING AVERAGE VALUE OF S MAY BE USED :
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AVIATION GASOLINE
LIGHT NAPHTHA C9-I4L3 RVP)
NAPHTHA (2-8 LS RVP)
FOLLOW-
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Figure 4.3-8. Vapor pressures of gasolines and finished petroleum products.
4.3-8
EMISSION FACTORS
4/77
-------
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4/77
Figure 4.3-9. Vapor pressures of crude oil.
Evaporation Loss Sources
4.3-9
-------
Table 4.3-2. PAINT FACTORS FOR FIXED ROOF TANKS3
Tank color
Roof
White
Aluminum (specular)
White
Aluminum (specular)
White
Aluminum (diffuse)
White
Light gray
Medium gray
Shell
White
White
Aluminum (specular)
Aluminum (specular)
Aluminum (diffuse)
Aluminum (diffuse)
Gray
Light gray
Medium gray
Paint factors (Fp)
Paint condition
Good
1.00
1.04
1.16
1.20
1.30
1.39
1.30
1.33
1.40
Poor
1.15
1.18
1.24
1.29
1.38
1.46
1.38
1.44a
1.58a
aEstimated from the ratios of the seven preceding paint factors.
ADJUSTMENT FACTOR C
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10 20
TANK DIAMETER IN FEET
Figure 4.3-10. Adjustment factor (C) for
small diameter tanks.
30
Fixed roof working losses can be estimated from:
LW = 2.40 x ID'2 MPKNKC
(2)
4.3-10
EMISSION FACTORS
4/77
-------
where: L
W
M
P
K
Kc
Fixed roof working loss (lb/103 gal throughput).
Molecular weight of vapor in storage tank (Ib/lb mole), see Table 4.3-1.
True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9,
or Table 4.3-1.
Turnover factor (dimensionless); see Figure 4.3-11.
Crude oil factor (dimensionless); see note.
Note: Kc = (0.84) for crude oil, K = (1.0) for gasoline and all other liquids.
1.0
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NOTE: FOR 38 TURNOVERS PER
YEAR OR LESS. KN -1.0
100
200
300
400
TURNOVERS PER YEAR
ANNUAL THROUGHPUT
TANK CAPACITY
Figure 4.3-11. Turnover factor (K|\|) for fixed roof tanks.
The fixed roof working loss (L\^)is the sum of the loading and unloading loss. API reports that special
tank operating conditions may result in actual losses which are significantly greater or lower than the
estimates provided by Equation (2).
The API recommends the use of these storage loss equations only for cases in which the stored petro-
leum liquids exhibit vapor pressures in the same range as gasolines. However, in the absence of any cor-
relation developed specifically for naphthas, kerosenes, and fuel oils, it is recommended that these
storage loss equations also be used for the storage of these heavier fuels.
The method most commonly used to control emissions from fixed roof tanks is a vapor recovery sys-
tem that collects emissions from the storage vessels and converts them to liquid product. To recover va-
por, one or a combination of four methods may be used: vapor/liquid absorption, vapor compression,
vapor cooling, and vapor/solid adsorption. Overall control efficiencies of vapor recovery systems vary
4/77
Evaporation Loss Sources
4.3-11
-------
from 90 to 95 percent, depending on the method used, the design of the unit, the composition of vapors
recovered, and the mechanical condition of the system.
Emissions from fixed roof tanks can also be controlled by the addition of an internal floating cover
or covered floating roof to the existing fixed roof tank. API reports that this can result in an average
loss reduction of 90 percent of the total evaporation loss sustained from a fixed roof tank.8
Evaporative emissions can be minimized by reducing tank heat input with water sprays, mechani-
cal cooling, underground storage, tank insulation, and optimum scheduling of tank turnovers.
4.3.2.2 Floating Roof Tanks3'7 - Floating roof standing storage losses can be estimated from:
LS = 9.21 x ID"3 M^-j^J0'7 Dl-5vwO-7KtKsKpKc (3)
where: LC = Floating roof standing storage loss (Ib/day).
M = Molecular weight of vapor in storage tank (Ib/lb mole); see Table 4.3-1.
P = True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9,
or Table 4.3-1.
D = Tank diameter (ft); see note (1).
Vw = Average wind velocity (mi/hr); see note (2).
Kt = Tank type factor (dimensionless); see Table 4.3-3.
Kg = Seal factor (dimensionless); see Table 4.3-3.
K = Paint factor (dimensionless); see Table 4.3-3.
K = Crude oil factor (dimensionless); see note (3).
Note: (1) For D > 150, use D/Tso" instead of D.1 5
(2) API correlation was derived for minimum wind velocity of 4 mph. If Vw
<. 4 mph, use Vw = 4mph.
(3) Kc = (0.84) for crude oil, Kc = (1.0) for all other liquids.
API reports that standing storage losses from gasoline and crude oil storage calculated from Equa-
tion (3) will not deviate from the actual losses by more than ±25 percent for tanks in good condition un-
der normal operation. However, losses may exceed the calculated amount if the seals are in poor condi-
tion. Although the API recommends the use of these correlations only for petroleum liquids exhibit-
ing vapor pressures in the range of gasoline and crude oils, in the absence of better correlations, these
correlations are also recommended with caution for use with heavier naphthas, kerosenes, and fuel
oils.
4.3-12 EMISSION FACTORS 4/77
-------
Table 4.3-3, TANK, TYPE, SEAL, AND PAINT FACTORS
FOR FLOATING ROOF TANKS2
Tank type
Welded tank with pan or pontoon
roof, single or double seal
Riveted tank with pontoon roof,
double seal
Riveted tank with pontoon roof,
single seal
Riveted tank with pan roof,
double seal
Riveted tank with pan roof,
single seal
Kt
0.045
0.11
0.13
0.13
0.14
Seal type
Tight fitting (typical of modern
metallic and non-metallic seals)
Loose fitting (typical of seals
built prior to 1942)
Paint color of shell and roof
Light gray or aluminum
White
Ks
1.00
1.33
Kp
1.0
0.9
API has developed a correlation based on laboratory data for calculating floating roof withdrawal
loss for gasoline storage.5 Floating roof withdrawal loss for gasoline can be estimated from:
22.4 d Cp
= —
(4)
where:
D
= Floating roof gasoline withdrawal loss (lb/103 gal throughput).
= Density of stored liquid at bulk liquid conditions (Ib/gal); see Table 4.3-1.
= Tank construction factor (dimensionless); see note.
= Tank diameter (ft).
Note: CF = (0.02) for steel tanks, Cp = (1.0) for gunite-lined tanks.
Because Equation (4) was derived from gasoline data, its applicability to other stored liquids is uncer-
tain. No estimate of accuracy of Equation (4) has been given.
API has not presented any correlations that specifically pertain to internal floating covers or cov-
ered floating roofs. Currently, API recommends the use of Equations (3) and (4) with a wind speed of 4
mph for calculating the losses from internal floating covers and covered floating roofs.
Evaporative emissions from floating roof tanks can be minimized by reducing tank heat input.
4.3.2.3 Variable Vapor Space Systems 4«7- Variable vapor space system filling losses can be estimated
from:
-, M P
Lv = (2.40 x ID'2) ~-
- (0.25 V2 N)]
(5)
4/77
Evaporation Loss Sources
4.3-13
-------
where: Ly = Variable vapor space filling loss (lb/103 gal throughput).
M = Molecular weight of vapo.r in storage tank (Ib/lb mole); see Table 4.3-1.
P = True vapor pressure at bulk liquid conditions (psia); see Figures 4.3-8, 4.3-9, or Table
4.3-1.
Vj = Volume of liquid pumped into system: throughput (bbl).
V2 = Volume expansion capacity of system (bbl); see note (1).
N = Number of transfers into system (dimensionless); see note (2).
Note: (1) V is the volume expansion capacity of the variable vapor space achieved by roof-
lifting or diaphragm-flexing.
(2) N is the number of transfers into the system during the time period that corre-
sponds to a throughput of Vr
The accuracy of Equation (5) is not documented; however, API reports that special tank operating
conditions may result in actual losses which are significantly different from the estimates provided by
Equation (5). It should also be noted that, although not developed for use with heavier petroleum
liquids such as kerosenes and fuel oils, Equation (5) is recommended for use with heavier petroleum
liquids in the absence of better data.
Evaporative emissions from variable vapor space tanks are negligible and can be minimized by opti-
mum scheduling of tank turnovers and by reducing tank heat input. Vapor recovery systems can be
used with variable vapor space systems to collect and recover filling losses.
Vapor recovery systems capture hydrocarbon vapors displaced during filling operations and re-
cover the hydrocarbon vapors by the use of refrigeration, absorption, adsorption, and/or compres-
sion. Control efficiencies range from 90 to 98 percent, depending on the nature of the vapors and the
recovery equipment used.
4.3.2.4 Pressure Tanks - Pressure tanks incur vapor losses when excessive internal pressures result in
relief valve venting. In some pressure tanks vapor venting is a design characteristic, and the vented
vapors must be routed to a vapor recovery system. However, for most pressure tanks vapor venting is
not a normal occurrence, and the tanks can be considered closed systems. Fugitive losses are also as-
sociated with pressure tanks and their equipment, but with proper system maintenance they are in-
significant. Correlations do not exist for estimating vapor losses from pressure tanks.
4.3.3 Emission Factors
Equations (1) through (5) can be used to estimate evaporative losses, provided the respective para-
meters are known. For those cases where such parameters are unknown, Table 4.3-4 provides emission
factors for the typical systems and conditions. It should be emphasized that these emission factors are
rough estimates at best for storage of liquids other than gasoline and crude oil, and for storage con-
ditions other than the ones they are based upon. In areas where storage sources contribute a substan-
tial portion of the total evaporative emissions or where they are major factors affecting the air quality,
it is advisable to obtain the necessary parameters and to calculate emission estimates using Equations
(1) through (5).
4.3-14 EMISSION FACTORS 4/77
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4/77
Evaporation Loss Sources
4.3-15
-------
4.3.3.1 Sample Calculation - Breathing losses from a fixed roof storage tank would be calculated as
follows, using Equation (1).
Design basis:
Tank capacity - 100,000 bbl.
Tank diameter - 125 ft.
Tank height - 46 ft.
Average diurnal temperature change - 15° F.
Gasoline RVP - 9 psia.
Gasoline temperature - 70°F.
Specular aluminum painted tank.
Roof slope is 0.1 ft/ft.
Fixed roof tank breathing loss equation:
LB = 2.21 xlO-4M -0'68 Dl-73 H0.51 AT0.50 F? c KC
where: M = Molecular weight of gasoline vapors (see Table 4.3-l)=!66.
P = True vapor of gasoline (see Figure 4.3-8) = 5.6 psia.
D = Tank diameter = 125 ft.
AT = average diurnal temperature change = 15° F.
F = paint factor (see Table 4.3-2) = 1.20.
C = tank diameter adjustment factor (see Figure 4.3-10) = 1.0.
KC = crude oil factor (see note for equation (1)) = 1.0.
H = average vapor space height. For a tank which is filled completely and emptied, the
average liquid level is 1/2 the tank rim height, or 23 ft. The effective cone height is 1/3
of the cone height. The roof slope is 0.1 ft/ft and the tank radius is 62.5 ft. Effective
cone height = (62.5 ft) (0.1 ft/ft) (1/3) = 2.08 ft.
H = average vapor space height = 23 ft + 2 ft = 25 ft.
Therefore:
LB = 2.21 x 10-4 (66) 147-_56' (125)1.73 (25)0-51 (15)0.50 (].2) (1.0) (1.0)
LB = 10681b/day
4.3-16 EMISSION FACTORS 4/77
-------
References for Section 4.3
1. Burklin, C.E. and R.L. Honerkamp. Revision of Evaporative Hydrocarbon Emission Factors,
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina. Report No.
EPA-450/3-76-039. August 15, 1976.
2. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Fixed-Roof
Tanks. Bull. 2518. Washington, D.C. 1962.
3. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Floating-Roof
Tanks. Bull. 2517. Washington, D.C. 1962.
4. American Petroleum Inst., Evaporation Loss Committee. Use of Variable Vapor-Space Systems
To Reduce Evaporation Loss. Bull. 2520. N.Y., N.Y. 1964
5. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Low-Pressure
Tanks. Bull. 2516. Washington, D.C. 1962.
6. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss In The Petroleum
Industry. Causes and Control. API Bull. 2513. Washington, D.C. 1959.
7. American Petroleum Inst., Div. of Refining, Petrochemical Evaporation Loss From Storage
Tanks. API Bull. 2523. New York. 1969
8. American Petroleum Inst., Evaporation Loss Committee. Use of Internal Floating Covers For
Fixed-Roof Tanks To Reduce Evaporation Loss. Bull. 2519. Washington, D.C. 1962.
9. Barnett, Henry C. et al. Properties Of Aircraft Fuels. Lewis Flight Propulsion Lab., Cleveland,
Ohio. NACA-TN 3276. August 1956.
4/77 Evaporation Loss Sources 4.3-17
-------
-------
4.4 TRANSPORTATION AND MARKETING , _, . r ,.
OF PETROLEUM LIQUIDS1 b? Charles C Masser
4.4.1 Process Description
As Figure 4.4-1 indicates, the transportation and marketing of petroleum liquids involves many
distinct operations, each of which represents a potential source of hydrocarbon evaporation loss.
Crude oil is transported from production operations to the refinery via tankers, barges, tank cars, tank
trucks, and pipelines. In the same manner, refined petroleum products are conveyed to fuel market-
ing terminals and petrochemical industries by tankers, barges, tank cars, tank trucks, and pipelines.
From the fuel marketing terminals, the fuels are delivered via tank trucks to service stations, commer-
cial accounts, and local bulk storage plants. The final destination for gasoline is usually a motor vehicle
gasoline tank. A similar distribution path may also be developed for fuel oils and other petroleum
products,
4.4.2 Emissions and Controls
Evaporative hydrocarbon emissions from the transportation and marketing of petroleum liquids
may be separated into four categories, depending on the storage equipment and mode of transporta-
tion used:
1, Large storage tanks: Breathing, working, and standing storage losses,
2. Marine vessels, tank cars, and tank trucks: Loading, transit, and ballasting losses.
3. Service stations: Bulk fuel drop losses and underground tank breathing losses.
4. Motor vehicle tanks: Refueling losses.
(In addition, evaporative and exhaust emissions are also associated with motor vehicle operation.
These topics are discussed in Chapter 3.)
4.4.2.1 Large Storage Tanks - Losses from storage tanks are thoroughly discussed in Section 4.3.
4.4.2.2 Marine Vessels, Tank Cars, and Tank Trucks - Losses from marine vessels, tank cars, and tank
trucks can be categorized into loading losses, transit losses, and ballasting losses.
Loading losses are the primary source of evaporative hydrocarbon emissions from marine vessel,
tank car, and tank truck operations. Loading losses occur as hydrocarbon vapors residing in empty
cargo tanks are displaced to the atmosphere by the liquid being loaded into the cargo tanks. The
hydrocarbon vapors displaced from the cargo tanks are a composite of (1) hydrocarbon vapors formed
in the empty tank by evaporation of residual product from previous hauls and (2) hydrocarbon vapors
generated in the tank as the new product is being loaded. The quantity of hydrocarbon losses from
loading operations is, therefore, a function of the following parameters:
• Physical and chemical characteristics of the previous cargo.
• Method of unloading the previous cargo.
4/77 Evaporation Loss Sources 4.4-1
-------
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EMISSION FACTORS
4/77
-------
• Operations during the transport of the empty carrier to the loading terminal.
• Method of loading the new cargo.
• Physical and chemical characteristics of the new cargo.
The principal methods of loading cargo carriers are presented in Figures 4.4-2,4.4-3, and 4.4-4. In
the splash loading method, the fill pipe dispensing the cargo is only partially lowered into the cargo
tank. Significant turbulence and vapor-liquid contacting occurs during the splash loading operation,
resulting in high levels of vapor generation and loss. If the turbulence is high enough, liquid droplets
will be entrained in the vented vapors.
FILL PIPE
VAPOR EMISSIONS
-HATCH COVER
CARGO TANK
Figure 4.4-2. Splash loading method.
VAPOR EMISSIONS
FILL PIPE
HATCH COVER
CARGO TANK
Figure 4.4-3. Submerged fill pipe.
A second method of loading is submerged loading. The two types of submerged loading are the
submerged fill pipe method and the bottom loading method. In the submerged fill pipe method, the
fill pipe descends almost to the bottom of the cargo tank. In the bottom loading method, the fill pipe
enters the cargo tank from the bottom. During the major portion of both forms of submerged loading
4/77
Evaporation Loss Sources
4.4-3
-------
VAPOR VENT
TO RECOVERY
OR ATMOSPHERE
HATCH CLOSED
mCARGO TANK
FILL PIPE
Figure 4.4-4. Bottom loading.
methods, the fill pipe opening is positioned below the liquid level. The submerged loading method
significantly reduces liquid turbulence and vapor-liquid contacting, thereby resulting in much lower
hydrocarbon losses than encountered during splash loading methods.
The history of a cargo carrier is just as important a factor in loading losses as the method of loading.
Hydrocarbon emissions are generally lowest from a clean cargo carrier whose cargo tanks are free from
vapors prior to loading. Clean cargo tanks normally result from either carrying a non-volatile liquid
such as heavy fuel oils in the previous haul, or from cleaning or venting the empty cargo tank prior to
loading operations. An additional practice, specific to marine vessels, that has significant impacton
loading losses is ballasting. After unloading a cargo, empty tankers normally fill several cargo tanks
with water to improve the tanker's stability on the return voyage. Upon arrival in port, this I ballast
water is pumped from the cargo tanks before loading the new cargo. The ballasting of cargo tanks
reduces the quantity of vapor returning in the empty tanker, thereby reducing the quantity of vapors
emitted during subsequent tanker loading operations.
In normal dedicated service, a cargo carrier is dedicated to the transport of only one product and
does not clean or vent its tank between trips. An empty cargo tank in normal dedicated service will
retain a low but significant concentration of vapors which were generated by evaporation of residual
product on the tank surfaces. These residual vapors are expelled along with newly generated vapors
during the subsequent loading operation.
Another type of cargo carrier is one in "dedicated balance service." Cargo carriers in dedicated
balance service pick up vapors displaced during unloading operations and transport these vapors in
the empty cargo tanks back to the loading terminal. Figure 4.4-5 shows a tank truck in dedicated vapor
balance service unloading gasoline to an underground service station tank and filling up with dis-
placed gasoline vapors to be returned to the truck loading terminal. The vapors in an empty cargo
carrier in dedicated balance service are normally saturated with hydrocarbons.
4.4-4
EMISSION FACTORS
4/77
-------
MANIFOLD FOR RETURNING VAPORS
VAPOR VENT LINE
TRUCK STORAGE\ I /\ \l\
COMPARTMENTS^ I *
UNDERGROUND
STORAGE TANK
Figure 4.4-5. Tanktruck unloading into an underground service station storage tank.
Tanktruck is practicing "vapor balance" form of vapor control.
Emissions from loading hydrocarbon liquid can be estimated (within 30 percent) using the follow-
ing expression:
LL = 12.46
(i)
where: L^ = Loading loss, lb/103 gal of liquid loaded.
M = Molecular weight of vapors, Ib/lb-mole (see Table 4.3-l)>
P = True vapor pressure of liquid loading, psia (see Figures 4.3-8 and
4.3-9, and Table 4.3-1).
T = Bulk temperature of liquid loaded, °R.
S = A saturation factor (see Table 4.4-1).
4/77 Evaporation Loss Sources
4.4-5
-------
The saturation factor (S) represents the expelled vapor's fractional approach to saturation and
accounts for the variations observed in emission rates from the different unloading and loading
methods. Table 4.4-1 lists suggested saturation factors (S).
Table 4.4-1. S FACTORS FOR CALCULATING PETROLEUM
LOADING LOSSES
Cargo carrier
Tank trucks and tank cars
Marine vessels3
Mode of operation
Submerged loading of a clean
cargo tank
Splash loading of a clean
cargo tank
Submerged loading: normal
dedicated service
Splash loading: normal
dedicated service
Submerged loading: dedicated,
vapor balance service
Splash loading: dedicated,
vapor balance service
Submerged loading: ships
Submerged loading: barges
S factor
0.50
1.45
0.60
1.45
1.00
1.00
0.2
0.5
aTo be used for products other than gasoline; use factors from Table 4.4-2
for marine loading of gasoline.
Recent studies on gasoline loading losses from ships and barges have led to the development of
more accurate emission factors for these specific loading operations. These factors are presented in
Table 4.4-2 and should be used instead of Equation (1) for gasoline loading operations at marine
terminals.2
Ballasting operations are a major source of hydrocarbon emissions associated with unloading
petroleum liquids at marine terminals. It is common practice for large tankers to fill several cargo
tanks with water after unloading their cargo. This water, termed ballast, improves the stability of the
empty tanker on rough seas during the subsequent return voyage. Ballasting emissions occur as hydro-
carbon-laden air in the empty cargo tank is displaced to the atmosphere by ballast water being pumped
into the empty cargo tank. Although ballasting practices vary quite a bit, individual cargo tanks are
ballasted about 80 percent, and the total vessel is ballasted approximately 40 percent of capacity.
Ballasting emissions from gasoline and crude oil tankers are approximately 0.8 and 0.6 lb/103 gal,
respectively, based on total tanker capacity. These estimates are for motor gasolines and medium
volatility crudes (RVP*5 psia).2
An additional emission source associated with marine vessel, tank car, and tank truck operations is
transit losses. During the transportation of petroleum liquids, small quantities of hydrocarbon vapors
are expelled from cargo tanks due to temperature and barometric pressure changes. The most signifi-
cant transit loss is from tanker and barge operations and can be calculated using Equation (2).3
4.4-6
EMISSION FACTORS
4/77
-------
Table 4.4-2. HYDROCARBON EMISSION FACTORS FOR GASOLINE LOADING OPERATIONS
Vessel tank condition
Cleaned and vapor free
lb/103 gal transferred
kg/103 liter transferred
Ballasted
lb/1Q3 gal transferred
kg/103 liter transferred
Uncleaned - dedicated service
lb/!03 gal transferred
kg/IO3 liter transferred
Average cargo tank condition
lb/1Q3 gal transferred
kg/103 liter transferred
Hydrocarbon emission factors
Ships
Range
0 to 2.3
0 to 0.28
0.4 to 3
0.05 to 0.36
0.4 to 4
0.05 to 0.48
a
Average
1.0
0.12
1.6
0.19
2.4
0.29
1.4
0.17
Ocean barges
Range
0 to 3
0 to 0.36
0.5 to 3
0.06 to 0.36
0.5 to 5
0.06 to 0.60
a
Average
1.3
0.16
2.1
0.25
3.3
0.40
a
Barges
Range
a
b
1.4 to 9
0.17 to 1.08
a
Average
1.2
0.14
b
4.0
0.48
4.0
0.48
aThese values are not available.
Barges are not normally ballasted
LT = 0.1 PW
(2)
where: L_, = Transit loss, lb/week-103 gal transported.
P = True vapor pressure of the transported liquid, psia
(see Figures 4.3-8 and 4.3-9, and Table 4.3-1).
W = Density of the condensed vapors, Ib/gal (see Table 4.3-1).
In the absence of specific inputs for Equations (1) and (2), typical evaporative hydrocarbon emis-
sions from loading operations are presented in Table 4.4-3. It should be noted that, although the crude
oil used to calculate the emission values presented in Table 4.4-3 has an RVP of 5, the RVP of crude oils
can range over two orders of magnitude. In areas where loading and transportation sources are major
factors affecting the air quality it is advisable to obtain the necessary parameters and to calculate
emission estimates from Equations (1) and (2).
Control measures for reducing loading emissions include the application of alternate loading
methods producing lower emissions and the application of vapor recovery equipment. Vapor recovery
equipment captures hydrocarbon vapors displaced during loading and ballasting operations and re-
covers the hydrocarbon vapors by the use of refrigeration, absorption, adsorption, and/or compres-
sion. Figure 4.4-6 demonstrates the recovery of gasoline vapors from tank trucks during loading oper-
ation at bulk terminals. Control efficiencies range from 90 to 98 percent depending on the nature of
the vapors and the type of recovery equipment employed.4
4/77
Evaporation Loss Sources
4.4-7
-------
Table 4.4-3. HYDROCARBON EMISSION FACTORS FOR PETROLEUM LIQUID
TRANSPORTATION AND MARKETING SOURCES
Emission source
Tank cars/trucks
Submerged loading-normal service
lb/103 gal transferred
kg/103 liters transferred
Splash loading-normal service
lb/103 gal transferred
kg/103 liters transferred
Submerged loading-balance service
lb/103 gal transferred
kg/103 liters transferred
Splash loading-balance service
lb/103 gal transferred
kg/103 liters transferred
Marine vessels
Loading tankers
lb/103 gal transferred
kg/103 liters transferred
Loading barges
lb/103 gal transferred
kg/103 liters transferred
Tanker ballasting
lb/103 gal cargo capacity
kg/1 03 liters cargo capacity
Transit
lb/week-103 gal transported
kg/week-103 liters transported
Product emission factors
Gasoline
5
0.6
12
1.4
8
1.0
8
1.0
b
b
0.8
0.10
3
0.4
Crude
oil
3
0.4
7
0.8
5
0.6
5
0.6
0.7
0.08
1.7
0.20
0.6
0.07
1
0.1
Jet
naphtha
(JP-4)
1.5
0.18
4
0.5
2.5
0.3
2.5
0.3
0.5
0.06
1.2
0.14
c
0.7
0.08
Jet
kerosene
0.02
0.002
0.04
0.005
a
a
0.005
0.0006
0.013
0.0016
c
0.02
0.002
Distillate
oil
No. 2
0.01
0.001
0.03
0.004
a
a
0.005
0.0006
0.012
0.0014
c
0.005
0.0006
Residual
oil
No. 6
0.0001
0.00001
0.0003
0.00004
a
a
0.00004
5x10-6
0.00009
1.1x10-5
c
3x10-5
4x10-6
1. Emission factors are calculated for dispensed fuel temperature of 60°F.
2. The example gasoline has an RVP of 10 psia.
3. The example crude oil has an RVP of 5 psia.
a. Not normally used.
b. See Table 4.4-2 for these emission factors.
c. Not Available.
Emissions from controlled loading operations can be calculated by multiplying the uncontrolled
emission rate calculated in Equations (1) and (2) by the control efficiency term:
(, efficiency
-
4.4.2.3 Sample Calculation - Loading losses from a gasoline tank truck in dedicated balance service
and practicing vapor recovery would be calculated as follows using Equation (1).
4.4-8
EMISSION FACTORS
4/77
-------
-------
Design basis:
Tank truck volume is 8000 gallons
Gasoline RVP is 9 psia
Dispensing temperature is 80° F
Vapor recovery efficiency is 95%
Loading loss equation:
eff
LT =12.46 -™-,.-rdQ
where: S = Saturation factor (see Table 4.4-1) = 1.0
P = True vapor pressure of gasoline (see Figure 4.3-8) = 6.6 psia
M = Molecular weight of gasoline vapors (see Table 4.3-1) ~66
T = Temperature of gasoline = 540° R
eff = The control efficiency = 95%
= 12 6 (1.0) (6.6) (66) / _95_
LI. iZAb^(1-Ioo
= 0.50 lb/103 gal
Total loading losses are
(0.50 lb/103 gal) (8.0 x 103 gal) = 4.0 Ib of hydrocarbon
4.4.2.4 Service Stations - Another major source of evaporative hydrocarbon emissions is the filling
of underground gasoline storage tanks at service stations. Normally, gasoline is delivered to service
stations in large (8000 gallon) tank trucks. Emissions are generated when hydrocarbon vapors in the
underground storage tank are displaced to the atmosphere by the gasoline being loaded into the tank.
As with other loading losses, the quantity of the service station tank loading loss depends on several
variables including the size and length of the fill pipe, the method of filling, the tank configuration,
and the gasoline temperature, vapor pressure, and composition. An average hydrocarbon emission
rate for submerged filling is 7.3 lb/103 gallons of transferred gasoline, and the rate for splash filling
is 11.5 lb/103 gallons of transferred gasoline (Table 4.4-4).4
Emissions from underground tank filling operations at service stations can be reduced by the use of
the vapor balance system (Figure 4.4-5). The vapor balance system employs a vapor return hose which
returns gasoline vapors displaced from the underground tank to the tank truck storage compartments
being emptied. The control efficiency of the balance system ranges from 93 to 100 percent. Hydrocar-
bon emissions from underground tank filling operations at a service station employing the vapor
balance system and submerged filling are not expected to exceed 0.3 lb/103 gallons of transferred
gasoline.
4.4-10 EMISSION FACTORS 4/77
-------
Table4.4-4. HYDROCARBON EMISSIONS FROM GASOLINE
SERVICE STATION OPERATIONS
Emission source
Filling underground tank
Submerged filling
Splash filling
Balanced submerged filling
Underground tank breathing
Vehicle refueling operations
Displacement losses
(uncontrolled)
Displacement losses
(controlled)
Spillage
Emission rate
lb/1Q3gal throughput
7.3
11.5
0.3
1
9
0.9
0.7
kg/10^ liters throughput
0.88
1.38
0.04
0.12
1.08
0.11
0.084
A second source of hydrocarbon emissions from service stations is underground tank breathing.
Breathing losses occur daily and are attributed to temperature changes, barometric pressure changes,
and gasoline evaporation. The type of service station operation also has a large impact on breathing
losses. An average breathing emission rate is 1 lb/103 gallons throughput.5
4.4.2.5 Motor Vehicle Refueling - An additional source of evaporative hydrocarbon emissions at
service stations is vehicle refueling operations. Vehicle refueling emissions are attributable to vapors
displaced from the automobile tank by dispensed gasoline and to spillage. The quantity of displaced
vapors is dependent on gasoline temperature, auto tank temperature, gasoline RVP, and dispensing
rates. Although several correlations have been developed to estimate losses due to displaced vapors,
significant controversy exists concerning these correlations. It is estimated that the hydrocarbon
emissions due to vapors displaced during vehicle refueling average 9 lb/103 gallons of dispensed
me.**
4,5
The quantity of spillage loss is a function of the type of service station, vehicle tank configuration,
operator technique, and operation discomfort indices. An overall average spillage loss is 0.7 lb/103
gallons of dispensed gasoline.6
Control methods for vehicle refueling emissions are based on conveying the vapors displaced from
the vehicle fuel tank to the underground storage tank vapor space through the use of a special hose and
nozzle (Figure 4.4-7). In the "balance" vapor control system, the vapors are conveyed by natural pres-
sure differentials established during refueling. In "vacuum assist" vapor control systems, the convey-
ance of vapors from the auto fuel tank to the underground fuel tank is assisted by a vacuum pump. The
overall control efficiency of vapor control systems for vehicle refueling emissions is estimated to be 88
to 92 percent.4
4/77
Evaporation Loss Sources
4.4-11
-------
SERVICE
STATION
PUMP
RETURNED VAPORS
![ j(L« DISPENSED GASOLINE
Figure 4.4-7. Automobile refueling vapor-recovery system.
References for Section 4.4
1. Burklin, C.E. and R.L. Honerkamp. Revision of Evaporative Hydrocarbon Emission Factors.
Research Triangle Park, N.C. EPA Report No. 450/3-76-039. August 15, 1976.
2. Burklin, Clinton E. et al. Background Information on Hydrocarbon Emissions From Marine
Terminal Operations, 2 Vols., EPA Report No. 450/3-76-038a and b. Research Triangle Park, N.C.
November 1976.
3. American Petroleum Inst., Evaporation Loss Committee. Evaporation Loss From Tank Cars,
Tank Trucks, and Marine Vessels. Washington, D.C. Bull. 2514. 1959.
4. Burklin, Clinton E. et al. Study of Vapor Control Methods For Gasoline Marketing Operations,
2 Vols. Radian Corporation. Austin, Texas. May 1975.
5. Scott Research Laboratories, Inc. Investigation Of Passenger Car Refueling Losses, Final Report,
2nd year program. EPA Report No. APTD-1453. Research Triangle Park, N.C. September 1972.
6. Scott Research Laboratories, Inc. Mathematical Expressions Relating Evaporative Emissions
From Motor Vehicles To Gasoline Volatility, summary report. Plumsteadville, Pennsylvania.
API Publication 4077. March 1971.
4.4-12
EMISSION FACTORS
4/77
-------
5. CHEMICAL PROCESS INDUSTRY
This section deals with emissions from the manufacture and use of chemicals or chemical products.
Potential emissions from many of these processes are high, but because of the nature of the compounds
they are usually recovered as an economic necessity. In other cases, the manufacturing operation is run
as a closed system allowing little or no escape to the atmosphere.
In general, the emissions that reach the atmosphere from chemical processes are primarily gaseous
and are controlled by incineration, adsorption, or absorption. In some cases, paniculate emissions
may also be a problem. The particulates emitted are generally extremely small and require very
efficient treatment for removal. Emission data from chemical processes are sparse. It was therefore
frequently necessary to make estimates of emission factors on the basis of material balances, yields, or
similar processes.
5.1 ADIPIC ACID fay Pain Canova
5.1.1 General1'2
Adipic acid, HOOC(CH2)4COOH, is a white crystalline solid used in the manufacture of synthetic
fibers, coatings, plastics, urethane foams, elastomers, and synthetic lubricants. Ninety percent of all
adipic acid produced in the United States is used in manufacturing Nylon 6,6. Cyclohexane is generally
the basic raw material used to produce adipic acid; however, one plant uses cyclohexanone, which is a
by-product of another process. Phenol has also been utilized, but has proved to be more expensive and
less readily available than cyclohexane.
During adipic acid production, the raw material, cyclohexane or cyclohexanone, is transferred to a
reactor, where it is oxidized at 260 to 330° F (130 to 170° C) to form a cyclohexanol/cyclohexanone
mixture. The mixture is then transferred to a second reactor and oxidized with nitric acid and a cata-
lyst (usually a mixture of cupric nitrate and ammonium vanadate) at 160 to 220° F (70 to 100° C) to
form adipic acid. The chemistry of these reactions is shown below.
M
H2CCH2
HoC-CHo-COOH
+ (a)HN03 *| + (b)NOx+(c) H20
H2CCH2 H2C-CH2-COOH
V
H2
Cyclohexanone + Nitric acid •- Adipic acid + Nitrogen oxides + Water
HOH
H26hH2
2 2
H2C-CH2-COOH
+ (x) HN03 | + (y) NOX + (z) H20
42 H2C-CH2-COOH
H2
Cyclohexanol + Nitric acid *• Adipic acid + Nitrogen oxides + Water
4/77 Chemical Process Industry 5.1-1
-------
Dissolved NOX gas plus any light hydrocarbon by-products are stripped from the adipic acid/nitric
acid solution with air and steam. Various organic acid by-products, namely acetic acid, glutaric acid,
and succinic acid, are also formed and may be recovered and sold by some plants.
The adipic acid/nitric acid solution is then chilled, and sent to a crystallizer where adipic acid
crystals are formed. The solution is centrifuged to separate the crystals. The remaining solution is sent
to another crystallizer, where any residual adipic acid is crystallized and centrifugally separated. The
crystals from the two centrifuges are combined, dried, and stored. The remaining solution is distilled
to recover nitric acid, which is routed back to the second reactor for re-use. Figure 5.1-1 presents a
general schematic of the adipic acid manufacturing process.
5.1.2 Emissions and Controls
Nitrogen oxides, hydrocarbons, and carbon monoxide are the major pollutants produced in adipic
acid production. The cyclohexane reactor is the largest source of CO and HC, and the nitric acid reactor
is the predominant source of NO*. Particulate emissions are low because baghouses are generally
employed for maximum product recovery and air pollution control. Figure 5.1-1 shows the points of
emission of these pollutants.
The most significant emissions of HC and CO come from the cyclohexane oxidation unit, which is
equipped with high- and low-pressure scrubbers. Scrubbers have a 90 percent collection efficiency of
HC and are used for economic reasons to recover expensive hydrocarbons as well as for pollution
control. Thermal incinerators, flaring, and carbon absorbers can all be used to limit HC emissions
from the cyclohexane oxidation unit with greater than 90 percent efficiency. CO boilers control CO
emissions with 99.99 percent efficiency and HC emissions with practically 100 percent efficiency. The
combined use of a CO boiler and a pressure scrubber results in essentially complete HC and CO con-
trol.
Three methods are presently used to control emissions from the NOX absorber: water scrubbing,
thermal reduction, and flaring or combustion in a powerhouse boiler. Water scrubbers have a low
collection efficiency of approximately 70 percent because of the extended length of time needed to
remove insoluble NO in the absorber offgas stream. Thermal reduction, in which offgases containing
NOX are heated to high temperatures and reacted with excess fuel in a reducing atmosphere, operates
at up to 97.5 percent efficiency and is believed to be the most effective system of control. Burning off-
gas in a powerhouse or flaring has an estimated efficiency of 70 percent.
Emission factors for adipic acid manufacture are listed in Table 5.1-1.
5.1-2 EMISSION FACTORS 4/77
-------
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4/77
Chemical Process Industry
5.1-3
-------
Table 5.1-1". EMISSION FACTORS FOR ADIPIC ACID MANUFACTURED
EMISSION FACTOR RATING: B
Process
Raw material storage
Uncontrolled
Cyclohexane oxidation
Uncontrolled0
W/boiler
W/thermal incinerator^
W/flarmge
W/carbon absorber'
W/scrubber plus boiler
Nitric acid reaction
UncontrollPdS
W/water scrubber"
W/thermal reduction'
W/flanng or combustion"
Adipic acid lefmmgl
Uncontrolled^
Adipic acid drying, loading,
and storage
Uncontrolled^
Particulate
Ib/ton
0
0
0
0
0
0
0
0
0
0
0
<0 1
0.8
kg/MT
0
0
0
0
0
Nitrogen J
oxides'3 ' Hydrocaibon
Ib/ton
0
0
0
0
0
0 0
0 0
0 53
0
0
0
<0 1
04
16
kg/MT Ib/ton
0 ' 22
0 ; 40
0 Meg1
0 Neg
0 4
0 2
0 Neg
27 0
8 0
1 0.5 0
16 , 8 0
06 03 05
0
0 , 0
kg/VIT
1 1
2C
Ne]
Neg
2
1
Neg
0
0
0
0
03
0
Carbon monoxide
Ib/ton
kg'MT
0 0
115
1
Neg
12
58
0 5
Neg
6
115 ' 58
Neg i Neg
0 , 0
0 0
0 . 0
0 0
0 , 0
0
0
aEmission factors are in units of pounds of pollutant per ton and kilograms of pollutant per metric ton of adipic acid produced.
b|\IOx is in the form of NO and NO2- Although large quantities of IM20 are also produced, N2O is not considered a criteria
pollutant and is not, therefore, included in these factors.
cUncontrolled emission factors are after scrubber processing since hydrocarbon recovery using scrubbers is an integral part of
adipic acid manufacturing.
dA thermal incinerator is assumed to reduce HC and CO emissions by approximately 99.99%.
eA flaring system is assumed to reduce HC and CO emissions by 90%.
fA carbon absorber is assumed to reduce HC emissions by 94% and to be ineffective in reducing CO emissions.
9Uncontrolled emission factors sre after NOX absorber since nitric acid recovery is an integral part of adipic acid manufacturing.
"Based on estimated 70% control.
'Based on estimated 97.5% control.
IRefining includes chilling, crystallization, centrifuging, and purification.
kParticulate emission factors are after baghouse control device.
Negligible.
References for Section 5.1
1. Screening Study to Determine Need for Standards of Performance for New Adipic Acid Plants.
GCA/Technology Division, Bedford, Mass. Prepared for Environmental Protection Agency,
Research Triangle Park, N.C. under Contract No. 68-02-1316. July 1976.
2. Kirk-Othmer Encyclopedia of Chemical Technology. Adipic Acid. Vol. 1, 2nd Ed. New York,
Interscience Encyclopedia, Inc. 1967. pp. 405-420.
5.1-4
EMISSION FACTORS
4/77
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5.2 AMMONIA
5.2.1 Process Description1
The manufacture of ammonia (NI^) is accomplished primarily by the catalytic reaction of hydrogen and
nitrogen at high temperatures and pressures. In a typical plant a hydrocarbon feed stream (usually natural gas) is
desulfurized, mixed with steam, and catalytically reformed to carbon monoxide and hydrogen. Air is introduced
into the secondary reformer to supply oxygen and provide a nitrogen to hydrogen ratio of 1 to 3. The gases then
enter a two-stage shift converter that allows the carbon monoxide to react with water vapor to form carbon
dioxide and hydrogen. The gas stream is next scrubbed to yield a gas containing less than 1 percent CC>2- A
methanator may be used to convert quantities of unreacted CO to inert CH4 before the gases, now largely
nitrogen and hydrogen in a ratio of 1 to 3, are compressed and passed to the converter. Alternatively, the gases
leaving the C02 scrubber may pass through a CO scrubber and then to the converter. The synthesis gases finally
react in the converter to form ammonia.
5.2.2 Emissions and Controls1
When a carbon monoxide scrubber is used before sending the gas to the converter, the regenerator offgases
contain significant amounts of carbon monoxide (73 percent) and ammonia (4 percent). This gas may be
scrubbed to recover ammonia and then burned to utilize the CO fuel valued
The converted ammonia gases are partially recycled, and the balance is cooled and compressed to liquefy the
ammonia. The noncondensable portion of the gas stream, consisting of unreacted nitrogen, hydrogen, and traces
of inerts such as methane, carbon monoxide, and argon, is largely recycled to the converter. To prevent the
accumulation of these inerts, however, some of the noncondensable gases must be purged from the system.
The purge or bleed-off gas stream contains about 15 percent ammonia.2 Another source of ammonia is the
gases from the loading and storage operations. These gases may be scrubbed with water to reduce the atmospheric
emissions. In addition, emissions of CO and ammonia can occur from plants equipped with CO-scrubbing systems.
Emission factors are presented in Table 5.2-1.
2/72 Chemical Process Industry 5.2-1
-------
Table 5.2-1. EMISSION FACTORS FOR AMMONIA MANUFACTURING WITHOUT
CONTROL EQUIPMENT3
EMISSION FACTOR RATING: B
Type of source
Plants with methanator
Purge gasc
Storage and loading0
Plants with CO absorber and
regeneration system
Regenerator exitd
Purge gasc
Storage and loading0
Carbon monoxide
Ib/ton
Neg
-
200
Neg
—
kg/MT
Neg
-
100
Neg
—
Hydrocarbons'3
Ib/ton
90
-
—
90
—
kg/MT
45
-
—
45
—
Ammonia
Ib/ton
3
200
7
3
200
kg/MT
1.5
100
3.5
1.5
100
References 2 and 3.
^Expressed as methane.
cAmmonia emissions can be reduced by 99 percent by passing through three stages of a packed-tower water scrubber. Hydro-
carbons are not reduced.
A two-stage water scrubber and incineration system can reduce these emissions to a negligible amount.
References for Section 5.2
1. Air Pollutant Emission Factors. Final Report. Resources Research, Incorporated. Reston, Virginia. Prepared
for National Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119.
April 1970.
2. Burns, W.E. and R.R. McMullan. No Noxious Ammonia Odor Here. Oil and Gas Journal, p. 129-131,
February 25, 1967.
3. Axelrod, L.C. and T.E. O'Hare. Production of Synthetic Ammonia. New York, M. W. Kellogg Company.
1964.
5.2-2
EMISSION FACTORS
2/72
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5.3 CARBON BLACK by Charles Mann
I
5.3.1 Process Description
Carbon black is produced by the reaction of a hydrocarbon fuel, such as oil or gas, with a limited
supply of combustion air at temperatures of 2500 to 3000° F (1370 to 1650° C). The unburned carbon is
collected as an extremely fine (10- to 400-nm diameter), black, fluffy particle. The three processes for
producing carbon black are the furnace process, thermal process, and channel process. In 1973 the
furnace process accounted for over 90 percent of production; the thermal process, 9 percent; and the
channel process, less than 1 percent. The primary use for carbon black is for strengthening rubber
products (mainly rubber tires); it is also used in printing inks, surface coatings, and plastics.
5.3.1.1 Furnace Process - Furnace black is produced by combustion of hydrocarbon feed in a refrac-
tory-lined furnace. Oil-fired furnaces now predominate. In this process (Figure 5.3-1) a heavy, aromatic
oil feed is preheated and fed into the furnace with about half of the air required for complete com-
bustion and a controlled amount of natural gas. The flue gases, which contain entrained carbon parti-
cles, are cooled to about 450° F (235° C) by passage through heat exchangers and water sprays. The
carbon black is then separated from the gas stream, usually by a fabric filter. A cyclone for primary
collection and particle agglomeration may precede the filter. A single collection system often serves a
number of furnaces that are manifolded together.
The recovered carbon black is finished to a marketable product by pulverizing and wet pelletizing
to increase bulk density. Water from the wet pelletizer is driven off in an indirect-fired rotary dryer.
The dried pellets are then conveyed to bulk storage. Process yields range from 35 to 65 percent, de-
pending on the particle size of the carbon black produced and the efficiency of the process. Furnace
designs and operating characteristics influence the particle size of the oil black. Generally, yields are
highest for large particle blacks and lowest for small particle sizes.
The older gas-furnace process is basically the same as the oil-furnace process except that a light
hydrocarbon gas is the primary feedstock and furnace designs are different. Some oil may also be
added to enrich the gas feed. Yields range from 10 to 30 percent, which is much less than in the oil
process, and comparatively coarser particles (40- to 80-nm diameter compared to 20- to 50-nm diameter
for oil-furnace blacks) are produced. Because of the scarcity of natural gas and the comparatively low
efficiency of the gas process, carbon black production by this method has been declining.
5.3.1.2 Thermal Process - The thermal process is a cyclic operation in which natural gas is thermally
decomposed to carbon particles, hydrogen, methane, and a mixture of other hydrocarbons. To start
the cycle, natural gas is burned to heat a brick checkerwork in the process furnace to about 3000° F
(1650°C). After this temperature is reached, the air supply is cut off, the furnace stack is closed, and
natural gas is introduced into the furnace. The natural gas is decomposed by the heat from the hot
bricks. When the bricks become cool, the natural gas flow is shut off. The effluent gases, containing
the thermal black particles, are flushed out of the furnace and cooled by water sprays to about 250°F
(125° C) before passing through cyclonic collectors and fabric filters, which recover the thermal black.
The effluent gases, consisting of about 90 percent hydrogen, 6 percent methane, and a mixture of
other hydrocarbons, are cooled, compressed, and used as a fuel to reheat the furnaces. Normally, more
than enough hydrogen is produced to make the thermal-black process self-sustaining, and the surplus
hydrogen is used to fire boilers that supply process steam and electric power.
The collected thermal black is pulverized and pelletized to a final product in much the same man-
ner as furnace black. Thermal-process yields are generally high (35 to 60 percent), but the relatively
4/77 Chemical Process Industry 5.3-1
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EMISSION FACTORS
4/77
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coarse particles produced (180- to 470-nm diameter) do not have the strong reinforcing properties re-
quired for rubber products.
5,3.1.3 Channel Process - In the channel-black process, natural gas is burned with a limited air supply
in long, low buildings. The flame from this burning impinges on long steel channel sections that swing
continuously over the flame. Carbon black deposited on the channels is scraped off into collecting
hoppers. The combustion gases, containing uncollected solid carbon, carbon monoxide, and other
combustion products, are then vented directly from the building. Yields from the channel-black
process are only 5 percent or less, but very fine particles are produced (10- to 30-nm diameter). Chan-
nel-black production has been declining steadily from its peak in the 1940's. Since 1974 no production
of channel black has been reported.
5.3.2 Emissions and Controls
Emissions from carbon black manufacture include particulates, sulfur compounds, carbon monox-
ide, hydrocarbons, and nitrogen oxides. Trace amounts of polynuclear organic matter (POM) are also
likely to be emitted. Emissions vary considerably from one process to another. Typical emission fac-
tors are given in Table 5.3-1.
The principal source of emissions in the furnace process is the main process vent. The vent stream
consists of the reactor effluent plus quench water vapor vented from the carbon-black recovery system.
Gaseous emissions vary considerably according to the grade of carbon black being produced. Hydro-
carbon and CO emissions tend to be higher for small-particle black production. Sulfur compound
emissions are a function of the feed sulfur content. Table 5.3-1 shows the normal emission ranges to be
expected from these variations in addition to typical average values. Some particulate emissions may
also occur from product transport, drier vents, the bagging and storage area, and spilled and leaked
materials. Such emissions are generally negligible, however, because of the high efficiency of collec-
tion devices and sealed conveying systems used to prevent product loss.
Particulate emissions from the furnace-black process are controlled by fabric filters that recover
the product from process and dryer vents. Particulate emissions control is therefore proportional to
the efficiency of the product recovery system. Some producers may use water scrubbers on the dryer
vent system.
Gaseous emissions from the furnace process may be controlled by CO boilers, incinerators, or
flares. The pellet dryer combustion furnace, which is in essence a thermal incinerator, may also be
employed in a control system. CO boilers, thermal incinerators, or combinations of these devices can
achieve essentially complete oxidation of CO, hydrocarbons, and reduced sulfur compounds in the
process flue gas. Particulate emissions may also be reduced by combustion of some of the carbon black
particles; however, emissions of sulfur dioxide and nitrogen oxides are increased by these combustion
devices.
Generally, emissions from the thermal process are negligible. Small amounts of nitrogen oxides
and particulates may be emitted during the heating part of the process cycle when furnace stacks are
open. Entrainment of carbon particles adhering to the checker brick may occur. Nitrogen oxides may
be formed since high temperatures are reached in the furnaces. During the decomposition portion of
the production cycle, the process is a closed system and no emissions would occur except through leaks.
Considerable emissions result from the channel process because of low efficiency of the process and
the venting of the exhaust gas directly to the atmosphere. Most of the carbon input to the process is lost
as CO, CO2, hydrocarbons, and particulate.
4/77 Chemical Process Industry 5.3-3
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5.3-4
EMISSION FACTORS
4/77
-------
References for Section 5.3
1. Air Pollutant Emission Factors. Final Report. Resources Research, Incorporated. Reston,
Virginia. Prepared for National Air Pollution Control Administration, Durham, N.C., under
Contract Number CPA-22-69-119. April 1970.
2. Drogin, I. Carbon Black. J. Air Pol. Control Assoc. 18:216-228, April 1968.
3. Cox, J.T. High Quality, High Yield Carbon Black. Chem. Eng. 57:116-117, June 1950.
4. Reinke, R.A. and T.A. Ruble. Oil Black. Ind. Eng. Chem. 44:685-694, April 1952.
5. Engineering and Cost Study of Air Pollution Control for the Petrochemical Industry, Volume 1:
Carbon Black Manufacture by the Furnace Process. Houdry Division, Air Products and Chem-
icals, Incorporated. Publication Number EPA-450/3-73-006a. June 1974.
6. Hustvedt, Kent C., Leslie B. Evans, and William M. Vatavuk. Standards Support and Environ-
mental Impact Statement, An Investigation of the Best Systems of Emission Reduction for
Furnace Process Carbon Black Plants in the Carbon Black Industry. U.S. Environmental
Protection Agency, Research Triangle Park, N.C. April 1976.
7. Carbon Black (Oil Black). Continental Carbon Company. Hydrocarbon Processing,, 52:111.
November 1973.
4/77 Chemical Process Industry 5.3-5
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5.4 CHARCOAL
5.4.1 Process Description1
Charcoal is generally manufactured by means of pyrolysis, or destructive distillation, of wood waste from
members of the deciduous hardwood species. In this process, the wood is placed in a retort where it is externally
heated for about 20 hours at 500 to 700°F (260 to 370°C). Although the retort has air intakes at the bottom,
these are only used during start-up and thereafter are closed. The entire distillation cycle takes approximately 24
hours, the last 4 hours being an exothermic reaction. Four units of hardwood are required to produce one unit of
charcoal.
5.4.2 Emissions and Controls1
In the pyrolysis of wood, all the gases, tars, oils, acids, and water are driven off, leaving virtually pure carbon.
All of these except the gas, which contains methane, carbon monoxide, carbon dioxide, nitrogen oxides, and
aldehydes, are useful by-products if recovered. Unfortunately, economics has rendered the recovery of the
distillate by-products unprofitable, and they are generally permitted to be discharged to the atmosphere. If a
recovery plant is utilized, the gas is passed through water-cooled condensers. The condensate is then refined while
the remaining cool, noncondensable gas is discharged to the atmosphere. Gaseous emissions can be controlled by
means of an afterburner because the unrecovered by-products are combustible. If the afterburner operates
efficiently, no organic pollutants should escape into the atmosphere. Emission factors for the manufacture of
charcoal are shown in Table 5.4-1.
Table 5.4-1. EMISSION FACTORS FOR CHARCOAL MANUFACTURING3-*1
EMISSION FACTOR RATING: C
Pollutant
Particulate (tar, oil)
Carbon monoxide
Hydrocarbons0
Crude methanol
Acetic acid
Other gases (HCHO, N2 NO)
Type of operation
With chemical
recovery plant
Ib/ton
320b
10013
60
kg/MT
160b
50b
30
Without chemical
recovery plant
Ib/ton
400
320b
10Qb
152
232
60b
kg/MT
200
16013
50b
76
116
3&
Calculated values based on data in Reference 2.
bEmissions are negligible if afterburner is used.
cExpressed as methane.
^Emission factors expressed in units of tons of charcoal produced.
References for Section 5.4
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company. 1967. p. 619..
4/77 Chemical Process Industry 5.4-1
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5.5 CHLOR-ALKALI
5.5.1 Process Description1
Chlorine and caustic are produced concurrently by the electrolysis of brine in either the diaphragm or mercury
cell. In the diaphragm cell, hydrogen is liberated at the cathode and a diaphragm is used to prevent contact of the
chlorine produced at the anode with either the alkali hydroxide formed or the hydrogen. In the mercury cell,
liquid mercury is used as the cathode and forms an amalgam with the alkali metal. The amalgam is removed from
the cell and is allowed to react with water in a separate chamber, called a denuder, to form the alkali hydroxide
and hydrogen.
Chlorine gas leaving the cells is saturated with water vapor and then cooled to condense some of the water.
The gas is further dried by direct contact with strong sulfuric acid. The dry chlorine gas is then compressed for
in-plant use or is cooled further by refrigeration to liquefy the chlorine.
Caustic as produced in a diaphragm-cell plant leaves the cell as a dilute solution along with unreacted brine.
The solution is evaporated to increase the concentration to a range of 50 to 73 percent; evaporation also
precipitates most of the residual salt, which is then removed by filtration. In mercury-cell plants, high-purity
caustic can be produced in any desired strength and needs no concentration.
5.5.2 Emissions and Controls1
Emissions from diaphragm- and mercury-cell chlorine plants include chlorine gas, carbon dioxide, carbon
monoxide, and hydrogen. Gaseous chlorine is present in the blow gas from liquefaction, from vents in tank cars
and tank containers during loading and unloading, and from storage tanks and process transfer tanks. Other
emissions include mercury vapor from mercury cathode cells and chlorine from compressor seals, header seals,
and the air blowing of depleted brine in mercury-cell plants.
Chlorine emissions from chlor-alkali plants may be controlled by one of three general methods: (l)use of the
gas in other plant processes, (2) neutralization in alkaline scrubbers, and (3) recovery of chlorine from effluent gas
streams. The effect of specific control practices is shown to some extent in the table on emission factors (Table
5.5-1).
References for Section 5.5
1. Atmospheric Emissions from Chlor-Alkali Manufacture. U.S. EPA, Air Pollution Control Office. Research
Triangle Park, N.C. Publication Number AP-80. January 1971.
2. Duprey, R.L. Compilation of Air Pollutant Emission Factors. U.S. DREW, PHS, National Center for Air
Pollution Control. Durham, N.C. PHS Publication Number 999-AP-42. 1968. p. 49.
2/72 Chemical Process Industry 5.5-1
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Table 5.5-1. EMISSION FACTORS FOR CHLOR-ALKALI PLANTS3
EMISSION FACTOR RATING: B
Type of source
Liquefaction blow gases
Diaphragm cell, uncontrolled
Mercury cell"3, uncontrolled
Water absorber
Caustic or lime scrubber
Loading of chlorine
Tank car vents
Storage tank vents
Air-blowing of mercury-cell brine
Chlorine gas
lb/100tons
2,000 to 10,000
4,000 to 16,000
25 to 1,000
1
450
1,200
500
kg/100MT
1,000 to 5, 000
2,000 to 8,000
12.5 to 500
0.5
225
600
250
References 1 and 2.
^Mercury cells lose about 1.5 pounds mercury per 100 tons (0.75 kg/100 MT) of chlorine liquefied.
5.5-2
EMISSION FACTORS
2/72
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.6 EXPLOSIVES by Charles Mann
5.6.1 General1
An explosive is a material that, under the influence of thermal or mechanical shock, decomposes rapidly and
spontaneously with the evolution of large amounts of heat and gas. Explosives fall into two major categories:
high explosives and low explosives. High explosives are further subdivided into initiating or primary high
. explosives and secondary high explosives. Initiating high explosives are very sensitive and are generally used in
small quantities in detonators and percussion caps to set off larger quantities of secondary high explosives.
Secondary high explosives, chiefly nitrates, nitro compounds, and nitramines, are much less sensitive to
. mechanical or thermal shock, but explode with great violence when set off by an initiating explosive. The chief
secondary high explosives manufactured for commercial and military use are ammonium nitrate blasting agents
and 2.4. 6,-trinitrotoluene (TNT). Low explosives, such as black powder and nitrocellulose, undergo relatively
slow autocombustion when set off and evolve large volumes of gas in a definite and controllable manner. A
multitude of different types of explosives are manufactured. As examples of the production of a high explosive
and a low explosive, the production of TNT and nitrocellulose are discussed in this section.
5.6.2 TNT Production !'3
TNT may be prepared by either a continuous process or a batch, three-stage nitration process using toluene,
nitric acid, and sulfuric acid as raw materials. In the batch process, a mixture of oleum (fuming sulfuric acid) and
nitric acid that has been concentrated to a 97 percent solution is used as the nitrating agent. The overall reaction
may be expressed as:
CH3
+ 3HON02 + H2S04-^02N~To JN02 + 3H20 + H2SO4 (1)
NO2
Toluene Nitric Sulfuric TNT Water Sulfuric
acid acid acid
Spent acid from the nitration vessels is fortified with make-up 60 percent nitric acid before entering the next
nitrator. Fumes from the nitration vessels are collected and removed from the exhaust by an oxidation-
absorption system. Spent acid from the primary nitrator is sent to the acid recovery system in which the sulfuric
and nitric acid are separated. The nitric acid is recovered as a 60 percent solution, which is used for
re fortification of spent acid from the second and third nitrators. Sulfuric acid is concentrated in a drum
concentrator by boiling water out of the dilute acid. The product from the third nitration vessel is sent to the
wash house at which point asymmetrical isomers and incompletely nitrated compounds are removed by washing
with a solution of sodium sulfite and sodium hydrogen sulfite (Sellite). The wash waste (commonly called red
water) from the purification process is discharged directly as a liquid waste stream, is collected and sold, or is
concentrated to a slurry and incinerated in rotary kilns. The purified TNT is solidified, granulated, and moved to
the packing house for shipment or storage. A schematic diagram of TNT production by the batch process is
shown in Figure 5.6-1.
12/75 Chemical Process Industry 5.6-1
-------
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EMISSION FACTORS
12/75
-------
5.6.3 Nitrocellulose Production
Nitrocellulose is prepared by the batch-type "mechanical dipper" process. Cellulose, in the form of cotton
linters, fibers, or specially prepared wood pulp, is purified, bleached, dried, and sent to a reactor (niter pot)
containing a mixture of concentrated nitric acid and a dehydrating agent such as sulfuric acid, phosphoric acid,
or magnesium nitrate. The overall reaction may be expressed as:
C6H702(OH)3 + 3HON02 + H2S04 * C6H702(ON02)3 + 3 H20 + H2S04 (2)
Cellulose Nitric Sulfuric Nitrocellulose Water Sulfuric
acid acid acid
When nitration is complete, the reaction mixtures are centrifuged to remove most of the spent acid. The spent
acid is fortified and reused or otherwise disposed of. The centrifuged nitrocellulose undergoes a series of water
washings and boiling treatments for purification of the final product.
5.6.4 Emissions and Controls2'3'5
The major emissions from the manufacture of explosives are nitrogen oxides and acid mists, but smaller
amounts of sulfuric oxides and particulates may also be emitted. Emissions of nitrobodies (nitrated organic
compounds) may also occur from many of the TNT process units. These compounds cause objectionable odor
problems and act to increase the concentration of acid mists. Emissions of sulfur oxides and nitrogen oxides from
the production of nitric acid and sulfuric acid used for explosives manufacturing can be considerable. It is
imperative to identify all processes that may take place at an explosives plant in order to account for all sources
of emissions. Emissions from the manufacture of nitric and sulfuric acid are discussed in other sections of this
publication.
In the manufacture of TNT, vents from the furne recovery system, sulfuric acid concentrators, and nitric acid
concentrators are the principal sources of emissions. If open burning or incineration of waste explosives is
practiced, considerable emissions may result. Emissions may also result from the production of Sellite solution
and the incineration of red water. Many plants, however, now sell the red water to the paper industry where it is
of economic importance.
Principal sources of emissions from nitrocellulose manufacture are from the reactor pots and centrifuges,
spent acid concentrators, and boiling tubs used for purification.
The most important factor affecting emissions from explosives manufacture is the type and efficiency of the
manufacturing process. The efficiency of the acid and fume recovery systems for TNT manufacture will directly
affect the atmospheric emissions. In addition, the degree to which acids are exposed to the atmosphere during
the manufacturing process affects the NOX and SOX emissions. For nitrocellulose production, emissions are
influenced by the nitrogen content and the desired quality of the final product. Operating conditions will also
affect emissions. Both TNT and nitrocellulose are produced in batch processes. Consequently, the processes may
never reach steady state and emission concentrations may vary considerably with time. Such fluctuations in
emissions will influence the efficiency of control methods. Several measures may be taken to reduce emissions
from explosives manufacturing. The effects of various control devices and process changes upon emissions, along
with emission factors for explosives manufacturing, are shown in Table 5.6-1. The emission factors are all related
to the amount of product produced and are appropriate for estimating long-term emissions or for evaluating
plant operation at full production conditions. For short time periods or for plants with intermittent operating
schedules, the emission factors in Table 5.6-1 should be used with caution, because processes not associated with
the nitration step are often not in operation at the same time as the nitration reactor.
12/75 Chemical Process Industry 5.6-3
-------
Table 5.6-1. EMISSION FACTORS FOR
EMISSION FACTOR
Type of process
TNT - batch process'3
Nitration reactors
Fume recovery
Acid recovery
Nitric acid concentrators
Su If uric acid concentrators0
Electrostatic
precipitator (exit)
Electrostatic precipitator
with scrubber0"
Red water incinerator
Uncontrolled6
Wet scrubber
Sellite exhaust
TNT - continuous process^
Nitration reactors
Fume recovery
Acid recovery
Red water incinerator
NitrocelluloseS
Nitration reactors'1
Nitric acid concentrator
Sulfuric acid concentrator
Boiling tubs
Particulates
Ib/ton
—
-
-
-
—
25(0.03-126)
1
-
—
-
0.25(0.03-0.05)
—
—
-
—
kg/MT
—
-
-
—
—
12.5(0.015-63)
0.5
-
—
-
0.13(0.015-0.025)
—
—
—
—
Sulfur oxides
(S02)
Ib/ton
—
-
-
14(4-40)
Meg.
2(0.05-3.5)
2(0.05-3.5)
59(0.01-177)
—
-
0.24(0.05-0.43)
1.4(0.8-2)
_
68(0.4-135)
_
kg/MT
-
-
-
7(2-20)
Neg.
1(0.025-1.75)
1(0.025-1.75)
29.5(0.005-88)
-
--
0.12(0.025-0.22)
0.7(0.4-1)
—
34(0.2-67)
—
aFor some processes considerable variations in emissions have been reported. The average of the values reported is shown first,
with the ranges given in parentheses. Where only one number is given, only one source test was available.
Reference 5.
cAcid mist emissions influenced by nitrobody levels and type of fuel used in furnace.
dIMo data available for NOX emissions after the scrubber. It is assumed that NOX emissions are unaffected by the scrubber.
5.6-4
EMISSION FACTORS
12/75
-------
EXPLOSIVES MANUFACTURING3
IATING: C
Nitrogen oxides
(N02)
Ib/ton
25(6-38)
55(1-136)
37(16-72)
40(2-80)
40(2-80)
26(1.5-101)
5
—
8(6.7-10)
3(1-4.5)
(7(6.1-8.4)
14(3.7-34)
14(10-18)
2
kg/MT
12.5(3-19)
27.5(0.5-68)
18.5(8-36)
20(1-40)
20(1-40)
13(0.75-50)
2.5
-
4(3.35-5)
1.5(0.5-2.25)
3.5(3-4.2)
7(1.85-17)
7(5-9)
1
Nitric acid mist
(100%HNO3)
Ib/ton
1(0.3-1.9)
92(0.01-275)
-
-
-
-
—
1(0.3-1.9)
0.02(0.01-0.03)
-
19(0.5-36)
kg/MT
0.5(0.5-0.95)
46(0.005-137)
-
-
-
-
—
0.5(0.15-0.95)
0.01(0.005-0.015)
-
9.5(0.25-18)
__
Sulfuric acid mist
(100%H2SO4)
Ib/ton
-
9(0.3-27)
65(1-188)
5(4-6)
-
6(0.6-16)
-
-
0.3
kg/MT
-
4.5(0.15-13.5)
32.5(0.5-94)
2.5(2-3)
-
3(0.3-8)
-
-
0.3
eUse low end of range for modern, efficient units and high end of range for older, less efficient units.
Apparent reductions in NOX and paniculate after control may not be significant because these values are based on only one
test result.
9 Reference 4.
For product with low nitrogen content (12 percent), use high end of range. For products with higher nitrogen content, use lower
end of range.
12/75
Chemical Process Industry
5.6-5
-------
References for Section 5.6
1. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company, 1967. p. 383-395.^
2. Unpublished data on emissions from explosives manufacturing, National Air Pollution Control Administration,
Office of Criteria and Standards, Durham, N.C. June 1970.
3. Higgins, F.B., Jr., et al. Control of Air Pollution From TNT Manufacturing. (Presented at 60th annual meeting
of Air Pollution Control Association. Cleveland. June 1967. Paper 67-111.)
4. Air Pollution Engineering Source Sampling Surveys, Radford Army Ammunition Plant. U.S. Army
Environmental Hygiene Agency, Edgewood Arsenal, Md,
5. Air Pollution Engineering Source Sampling Surveys, Volunteer Army Ammunition Plant and Joliet Army
Ammunition Plant. U.S. Army Environmental Hygiene Agency, Edgewood Arsenal, Md.
5.6-6 EMISSION FACTORS 12/75
-------
5.7 HYDROCHLORIC ACID
Hydrochloric acid is manufactured by a number of different chemical processes. Approximately 80 percent of
the hydrochloric acid, however, is produced by the by-product hydrogen chloride process, which will be the only
process discussed in this section. The synthesis process and the Mannheim process are of secondary importance.
5.7.1 Process Description1
By-product hydrogen chloride is produced when chlorine is added to an organic compound such as benzene,
toluene, and vinyl chloride. Hydrochloric acid is produced as a by-product of this reaction. An example of a
process that generates hydrochloric acid as a by-product is the direct chlorination of benzene. In this process
benzene, chlorine, hydrogen, air, and some trace catalysts are the raw materials that produce chlorobenzene. The
gases from the reaction of benzene and chlorine consist of hydrogen chloride, benzene, chlorobenzenes, and air.
These gases are first scrubbed in a packed tower with a chilled mixture of monochlorobenzene and
dichlorobenzene to condense and recover any benzene or chlorobenzene. The hydrogen chloride is then absorbed
in a falling film absorption plant.
5.7.2 Emissions
The recovery of the hydrogen chloride from the chlorination of an organic compound is the major source of
hydrogen chloride emissions. The exit gas from the absorption or scrubbing system is the actual source of the
hydrogen chloride emitted. Emission factors for hydrochloric acid produced as by-product hydrogen chloride are
presented in Table 5.7-1.
Table 5.7-1. EMISSION FACTORS FOR HYDROCHLORIC
ACID MANUFACTURING3
EMISSION FACTOR RATING: B
Type of process
By-product hydrogen chloride
With final scrubber
Without final scrubber
Hydrogen chloride emissions
Ib/ton
0.2
3
kg/MT
0.1
1.5
aRefer
Reference for Section 5.7
1. Atmospheric Emissions from Hydrochloric Acid Manufacturing Processes. U.S. DHEW, PHS, CPEHS,
National Air Pollution Control Administration. Durham, N.C. Publication Number AP-54. September 1969.
2/72 Chemical Process Industry 5.7-1
-------
-------
5.8 HYDROFLUORIC ACID
5.8.1 Process Description'
All hydrofluoric acid in the United States is currently produced by the reaction of acid-grade fluorspar with
sulfuric acid for 30 to 60 minutes in externally fired rotary kilns at a temperature of 400° to 500°F (204° to
260°C).2-3'4 The resulting gas is then cleaned, cooled, and absorbed in water and weak hydrofluoric acid to form
a strong acid solution. Anhydrous hydrofluoric acid is formed by distilling 80 percent hydrofluoric acid and
condensing the gaseous HF which is driven off.
5.8.2 Emissions and Controls1
Air pollutant emissions are minimized by the scrubbing and absorption systems used to purify and recover the
HF. The initial scrubber utilizes concentrated sulfuric acid as a scrubbing medium and is designed to remove dust,
SCb, 803, sulfuric acid mist, and water vapor present in the gas stream leaving the primary dust collector. The
exit gases from the final absorber contain small amounts of HF, silicon tetrafluoride (SiF^, CC>2, and SC>2 and
may be scrubbed with a caustic solution to reduce emissions further. A final water ejector, sometimes used to
draw the gases through the absorption system, will reduce fluoride emissions. Dust emissions may also result from
raw fluorspar grinding and drying operations. Table 5.8-1 lists the emission factors for the various operations.
Table 5.8-1. EMISSION FACTORS FOR HYDROFLUORIC ACID MANUFACTURING3
EMISSION FACTOR RATING: C
Type of operation
Rotary kiln
Uncontrolled
Water scrubber
Grinding and drying
of fluorspar
Fluorides
Ib/ton acid
50
0.2
-
kg/MT acid
25
0.1
-
Participates
Ib/ton fluorspar
—
—
20b
kg/MT fluorspar
—
_
10b
References 2 and 5.
Factor given for well-controlled plant.
2/72
Chemical Process Industry
5.8-1
-------
References for Section 5.8
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc., Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-1 19. April 1970.
2. Rogers, W.E. and K. Muller. Hydrofluoric Acid Manufacture. Chem. Eng. Progr. 59:85-88, May 1963.
3. Heller, A.N., S.T. Cuffe, and D.R. Goodwin. Inorganic Chemical Industry. In: Air Pollution Engineering
. Manual. Danielson, J.A. (ed.). U.S. DHEW, PHS. National Center for Air Pollution Control. Cincinnati, Ohio.
Publication Number 999-AP-40. 1967. p. 197-198.
4. Hydrofluoric Acid. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 9. New York, John Wiley and
Sons, Inc. 1964. p. 444-485.
5. Private Communication between Resources Research, Incorporated, and E.I. DuPont de Nemours and
Company. Wilmington, Delaware. January 13, 1970.
5.8-2 EMISSION FACTORS 2/72
-------
5.9 NITRIC ACID Revised by William Vatavuk
5.9.1 Process Description
5.9.1.1 Weak Acid Production1 - Nearly all the nitric acid produced in the United States is manufactured by the
high-pressure catalytic oxidation of ammonia (Figure 5.9-1). Typically, this process consists of three steps, each
of which corresponds to a distinct chemical reaction. First, a 1:9 ammonia-air mixture is oxidized at high
temperature and pressure (6.4 to 9.2 atmospheres), as it passes through a platinum-rhodium catalyst, according to
the reaction:
4NH3 + 502 —»- 4NO + 6H20 (1)
Ammonia Oxygen Nitric Water
oxide
After the process stream is cooled to 100°F (38°C) or less by passage through a cooler-condenser, the nitric oxide
reacts with residual oxygen:
2ND + 02 -*- 2NO2 -*7" N204
Nitrogen Nitrogen (2)
dioxide tetroxide
Finally, the gases are introduced into a bubble-cap plate absorption column where they are contacted with a
countercurrent stream of water. The exothermic reaction that occurs is:
3N02 + H20 -*- 2HN03 + NO
Nitric acid (3)
50 to 70% aqueous
The production of nitric oxide in reaction (3) necessitates the introduction of a secondary air stream into the
column to effect its oxidation to nitrogen dioxide, thereby perpetuating the absorption operation.
The spent gas flows from the top of the absorption tower to an entrainment separator for acid mist removal,
through the ammonia oxidation unit for energy absorption from the ammonia stream, through an expander for
energy recovery, and finally to the stack. In most plants the stack gas is treated before release to the atmosphere
by passage through either a catalytic combustor or, less frequently, an alkaline scrubber.
5.9.1.2 High-Strength Acid Production1 - To meet requirements for high strength acid, the 50 to 70 percent acid
produced by the pressure process is concentrated to 95 to 99 percent at approximately atmospheric pressure. The
concentration process consists of feeding strong sulfuric acid and 60 percent nitric acid to the top of a packed
column where it is contacted by an ascending stream of weak acid vapor, resulting in the dehydration of thf
latter. The concentrated acid vapor that leaves the column passes to a bleacher and countercurrent condense
system to effect condensation of the vapors and separation of the small amounts of nitric oxides and oxygen th'
form as dehydration by-products. These by-products then flow to an absorption column where the nitric oxi- .
mixes with auxiliary air to form nitrogen dioxide, which is, in turn, recovered as weak nitric acid. Finally,
unreacted gases are vented to the atmosphere from the top of the column.
4/73 Chemical Process Industry 5.9-1
-------
AIR
i
COMPRESSOR
EXPANDER
EFFLUENT
STACK
J
CATALYTIC REDUCTION
-
-------
5.9.2 Emissions and Controls1"3
The emissions derived from nitric acid manufacture consist primarily of nitric oxide, which accounts for
visible emissions; nitrogen dioxide; and trace amounts of nitric acid mist. By far, the major source of nitrogen
oxides is the tail gas from the acid absorption tower (Table 5.9-1). In general, the quantity of NOX emissions is
directly related to the kinetics of the nitric acid formation reaction.
The specific operating variables that increase tail gas NOX emissions are: (1) insufficient air supply, which
results in incomplete oxidation of NO; (2) low pressure in the absorber; (3) high temperature in the
cooler-condenser and absorber; (4) production of an excessively high-strength acid; and (5) operation at high
throughput rates, which results in decreased residence time in the absorber.
Aside from the adjustment of these variables, the most commonly used means for controlling emissions is the
catalytic combustor. In this device, tail gases are heated to ignition temperature, mixed with fuel (natural gas,
hydrogen, or a mixture of both), and passed over a catalyst. The reactions that occur result in the successive
reduction of NCh to NO and, then, NO to N2- The extent of reduction of N02 to N^ in the combustor is, in
turn, a function of plant design, type of fuel used, combustion temperature and pressure, space velocity through
the combustor, type and amount of catalyst used, and reactant concentrations (Table 5.9-1).
Comparatively small amounts of nitrogen oxides are also lost from acid concentrating plants. These losses
(mostly N02) occur from the condenser system, but the emissions are small enough to be easily controlled by the
installation of inexpensive absorbers.
Table 5.9-1. NITROGEN OXIDE EMISSIONS FROM NITRIC ACID PLANTS3
EMISSION FACTOR RATING: B
Type of control
Weak acid
Uncontrolled
Catalytic combustor
(natural gas fired)
Catalytic combustor
(hydrogen fired)
Catalytic combustor
(75% hydrogen, 25%
natural gas fired)
High-strength acid
Control
efficiency, %
0
78 to 97
97 to 99.8
98 to 98.5
—
Emissions (N02)b
Ib/ton acid
50 to 55C
2to7d
0.0 to 1.5
0.8 to 1.1
0.2 to 5.0
kg/MT acid
25.0 to 27.5
1.0 to 3.5
0.0 to 0.75
0.4 to 0.55
0.1 to 2.5
References 1 and 2.
Based on 100 percent acid production.
cRange of values taken from four plants measured at following process conditions.
production rate, 120 tons (109 WIT) per day (100 percent rated capacity); absorber exit
temperature, 90° F (32° C); absorber exit pressure, 7.8 atmospheres;acid strength, 57
percent. Under different conditions, values can vary from 43 to 57 Ib/ton (21.5 to 28.5
kg/MT).
"To present a more realistic picture, ranges of values were used instead of averages.
4/73
Chemical Process Industry
5.9-3
-------
Acid mist emissions do not occur from a properly operated plant. The small amounts that may be present in
the absorber exit gas stream are removed by a separator or collector prior to entering the catalytic combustor or
expander.
Finally, small amounts of nitrogen dioxide are lost during the filling of storage tanks and tank cars.
Nitrogen oxide emissions (expressed as NC^) are presented for weak nitric acid plants in table 5.9-1. The
emission factors vary considerably with the type of control employed, as well as with process conditions. For
comparison purposes, the Environmental Protection Agency (EPA) standard for both new and modified plants is
3.0 pounds per ton of 100 percent acid produced (1.5 kilograms per metric ton), maximum 2-hour average,
expressed as NC^.4 Unless specifically indicated as 100 percent acid, production rates are generally given in terms
of the total weight of product (water and acid). For example, a plant producing 500 tons (454 MT) per day of 55
weight percent nitric acid is really producing only 275 tons (250 MT) per day of 100 percent acid.
References for Section 5.9
r
1. Control of Air Pollution from Nitric Acid Plants. Unpublished Report. Environmental Protection Agency,
Research Triangle Park, N.C.
2. Atmospheric Emissions from Nitric Acid Manufacturing Processes. U.S. DHEW, PHS, Division of Air
Pollution. Cincinnati, Ohio. Publication Number 999-AP-27. 1966.
3. Unpublished emission data from a nitric acid plant. U.S. DHEW, PHS, EHS, National Air Pollution Control
Administration, Office of Criteria and Standards. Durham, N.C. June 1970.
4. Standards of Performance for New Stationary Sources. Environmental Protection Agency, Washington, D.C.
Federal Register. 36(247): December 23,1971.
5.9-4 EMISSION FACTORS 4/73
-------
5.10 PAINT AND VARNISH
5.10.1 Paint Manufacturing1
The manufacture of paint involves the dispersion of a colored oil or pigment in a vehicle, usually an oil or
resin, followed by the addition of an organic solvent for viscosity adjustment. Only the physical processes of
weighing, mixing, grinding, tinting, thinning, and packaging take place; no chemical reactions are involved.
These processes take place in large mixing tanks at approximately room temperature.
The primary factors affecting emissions from paint manufacture are care in handling dry pigments, types of
solvents used, and mixing temperature.2-3 About 1 or 2 percent of the solvents is lost even under well-controlled
conditions. Particulate emissions amount to 0.5 to 1.0 percent of the pigment handled.4
5.10.2 Varnish Manufacturing1'3
The manufacture of varnish also involves the mixing and blending of various ingredients to produce a wide
range of products. However, in this case chemical reactions are initiated by heating. Varnish is cooked in either
open or enclosed gas-fired kettles for periods of 4 to 16 hours at temperatures of 200 to 650°F (93 to 340°C).
Varnish cooking emissions, largely in the form or organic compounds, depend on the cooking temperatures
and times, the solvent used, the degree of tank enclosure, and the type of air pollution controls used. Emissions
from varnish cooking range from 1 to 6 percent of the raw material.
To reduce hydrocarbons from the manufacture of paint and varnish, control techniques include condensers
and/or adsorbers on solvent-handling operations, and scrubbers and afterburners on cooking operations.
Emission factors for paint and varnish are shown in Table 5.10-1.
2/72 Chemical Process Industry 5.10-1
-------
Table 5.10-1. EMISSION FACTORS FOR PAINT AND VARNISH MANUFACTURING
WITHOUT CONTROL EQUIPMENT3-11
EMISSION FACTOR RATING: C
Type of
product
Paint
Varnish
Bodying oil
Oleoresinous
Alkyd
Acrylic
Participate
Ib/ton pigment
2
—
—
—
—
kg/MT pigment
1
-
—
-
—
Hydrocarbons0
Ib/ton of product
30
40
150
160
20
kg/MT pigment
15
20
75
80
10
References 2 and 4 through 8.
Afterburners can reduce gaseous hydrocarbon emissions by 99 percent and participates by about 90
percent. A water spray and oil filter system can reduce particulates by about 90 percent,
cExpressed as undefined organic compounds whose composition depends upon the type of varnish or
paint.
References for Section 5.10
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Stenburg, R.L. Atmospheric Emissions from Paint and Varnish Operations. Paint Varn. Prod. p. 61-65 and
111-114, September 1959.
3. Private Communication between Resources Research, Incorporated, and National Paint, Varnish and Lacquer
Association. September 1969.
4. Unpublished engineering estimates based on plant visits in Washington, D.C, Resources Research,
Incorporated. Reston, Va. October 1969.
5. Chatfield, H.E. Varnish Cookers. In: Air Pollution Engineering Manual. Danielson, J. A. (ed.). U.S. DHEW,
PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40. 1967. p.
688-695.
6. Lunche, E.G. et al. Distribution Survey of Products Emitting Organic Vapors in Los Angeles County. Chem.
Eng. Progr. 53. August 1957.
\
7. Communication on emissions from paint and varnish operations with G. Sallee, Midwest Research Institute.
December 17, 1969.
8. Communication with Roger Higgins, Benjamin Moore Paint Company. June 25, 1968 .
5.10-2
EMJS&IQJ^LFACTORS
2/72
-------
5.11 PHOSPHORIC ACID
Phosphoric acid is produced by two principal methods, the wet process and the thermal process. The wet
process is usually employed when the acid is to be used for fertilizer production. Thermal-process acid is normally
of higher purity and is used in the manufacture of high-grade chemical and food products.
5.11.1 Wet Process1 '2
In the wet process, finely ground phosphate rock is fed into a reactor with sulfuric acid to form phosphoric
acid and gypsum. There is usually little market for the gypsum produced, and it is handled as waste material in
gypsum ponds. The phosphoric acid is separated from the gypsum and other insolubles by vacuum filtration. The
acid is then normally concentrated to about 50 to 55 percent PiC^. When superphosphoric acid is made, the acid
is concentrated to between 70 and 85 percent ?2
Emissions of gaseous fluorides, consisting mostly of silicon tetrafluoride and hydrogen fluoride, are the major
problems from wet-process acid. Table 5.11-1 summarizes the emission factors from both wet-process acid and
thermal-process acid.
5. 1 1 .2 Thermal Process1
In the thermal process, phosphate rock, siliceous flux, and coke are heated in an electric furnace to produce
elemental phosphorus. The gases containing the phosphorus vapors are passed through an electrical precipitator to
remove entrained dust. In the "one-step" version of the process, the gases are next mixed with air to form P^O^
before passing to a water scrubber to form phosphoric acid. In the "two-step" version of the process, the
phosphorus is condensed and pumped to a tower in which it is burned with air, and the P^C^ formed is hydrated
by a water spray in the lower portion of the tower.
The principal emission from thermal-process acid is P2®5 ac'^ ni'st ^roni tne absorber tail gas. Since all plants
are equipped with some type of acid-mist collection system, the emission factors presented in Table 5.11-1 are
based on the listed types of control.
2/72 Chemical Process Industry 5.11-1
-------
Table 5.11-1. EMISSION FACTORS FOR PHOSPHORIC ACID PRODUCTION
EMISSION FACTOR RATING: B
Source
Wet process (phosphate rock)
Reactor, uncontrolled
Gypsum pond
Condenser, uncontrolled
Thermal process (phosphorus burned0)
Packed tower
Venturi scrubber
Glass-fiber mist eliminator
Wire-mesh mist eliminator
High-pressure-drop mist eliminator
Electrostatic precipitator
Particulates
Ib/ton
—
—
—
4.6
5.6
3.0
2.7
0.2
1.8
kg/MT
—
—
—
2.3
2.8
1.5
1.35
0.1
0.9
Fluorides
Ib/ton
18a
Ib
203
—
—
—
—
—
—
kg/MT
9a
1.1b
10a
—
—
—
—
-
—
References 2 and 3.
bPounds per acre per day (kg/hectare-day); approximately 0.5 acre (0.213 hectare) is
required to produce 1 ton of PO^B daily.
°Reference 4.
References for Section 5.11
1. Duprey, R.L. Compilation of Air Pollutant Emission Factors. U.S. DHEW, PHS, National Center for Air
Pollution Control. Durham, N.C. PHS Publication Number 999-AP-42. 1968. p. 16.
2. Atmospheric Emissions from Wet-Process Phosphoric Acid Manufacture. U.S. DHEW, PHS, EHS, National
Air Pollution Control Administration. Raleigh, N.C. Publication Number AP-57. April 1970.
3. Control Techniques for Fluoride Emissions. Internal document. U.S. EPA, Office of Air Programs. Research
Triangle Park, N.C. 1970.
4. Atmospheric Emissions from Thermal-Process Phosphoric Acid Manufacturing. Cooperative Study Project:
Manufacturing Chemists' Association, Incorporated, and Public Health Service. U.S. DHEW, PHS, National
Air Pollution Control Administration. Durham, N.C. Publication Number AP-48. October 1968.
5.11-2
EMISSION FACTORS
2/72
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5.12 PHTHALIC ANHYDRIDE
5.12.1 General1
by Pam Canova
Phthalic anhydride (PAN) production in the United States in 1972 was 0.9 billion pounds per year;
this total is estimated to increase to 2.2 billion pounds per year by 1985. Of the current production, 50
percent is used for plasticizers, 25 percent for alkyd resins, 20 percent for unsaturated polyester resins,
and 5 percent for miscellaneous and exports. PAN is produced by catalytic oxidation of either ortho-
xylene or naphthalene. Since naphthalene is a higher priced feedstock and has a lower feed utilization
(about 1.0 Ib PAN/lb o-xylene versus 0.97 Ib PAN/lb naphthalene), future production growth is pre-
dicted to utilize o-xylene. Because emission factors are intended for future as well as present applica-
tion, this report will focus mainly on PAN production utilizing o-xylene as the main feedstock.
The processes for producing PAN by o-xylene or naphthalene are the same except for reactors,
catalyst handling, and recovery facilities required for fluid bed reactors.
In PAN production using o-xylene as the basic feedstock, filtered air is preheated, compressed, and
mixed with vaporized o-xylene and fed into the fixed-bed tubular reactors. The reactors contain the
catalyst, vanadium pentoxide, and are operated at 650 to 725°F (340 to 385°C). Small amounts of
sulfur dioxide are added to the reactor feed to maintain catalyst activity. Exothermic heat is removed
by a molten salt bath circulated around the reactor tubes and transferred to a steam generation system.
Naphthalene-based feedstock is made up of vaporized naphthalene and compressed air. It is
transferred to the fluidized bed reactor and oxidized in the presence of a catalyst, vanadium pent-
oxide, at 650 to 725° F (340 to 385° C). Cooling tubes located in the catalyst bed remove the^xothermic
heat which is used to produce high-pressure steam. The reactor effluent consists of PAN vapors, en-
trained catalyst, and various by-products and non-reactant gas. The catalyst is removed by filtering and
returned to the reactor.
The chemical reactions for air oxidation of o-xylene and naphthalene are as follows.
302
3H20
o-xylene + oxygen
phthalic water
anhydride
»^>
1
SN
0
II
- P
C
NX ~ U
>
naphthalene +
2H20 + 2C02
4/77
anhydride
Chemical Process Industry
0
phthalic + water + carbon
anhydride dioxide
5.12,1
-------
The reactor effluent containing crude PAN plus products from side reactions and excess oxygen passes
to a series of switch condensers where the crude PAN cools and crystallizes. The condensers are alter-
nately cooled and then heated, allowing PAN crystals to form and then melt from the condenser tube
fins.
The crude liquid is transferred to a pretreatment section in which phthulic acid is dehydrated to
anhydride. Water, maleic anhydride, and benzoic acid are partially evaporated. The liquid then goes
to a vacuum distillation section where pure PAN (99.8 wt. percent pure) is recovered. The product can
be stored and shipped either as a liquid or a solid (in which case it is dried, flaked, and packaged in
multi-wall paper bags). Tanks for holding liquid PAN are kept at 300°F (150°C) and blanketed with
dry nitrogen to prevent the entry of oxygen (fire) or water vapor (hydrolysis to phthalic acid).
Maleic anhydride is currently the only by-product being recovered.
Figures 1 and 2 show the process flow for air oxidation of o-xylene and naphthalene, respectively.
5.12.2 Emissions and Controls1
Emissions from o-xylene and naphthalene storage are small and presently are not controlled.
The major contributor of emissions is the reactor and condenser effluent which is vented from the
condenser unit. Particulate, sulfur oxides (for o-xylene-based production), and carbon monoxide
make up the emissions, with carbon monoxide comprising over half the total. The most efficient (96
percent) system of control is the combined usage of a water scrubber and thermal incinerator. A
thermal incinerator alone is approximately 95 percent efficient in combustion of pollutants for o-
xylene-based production, and 80 percent efficient for naphthalene-based production. Thermal incin-
erators with steam generation show the same efficiencies as thermal incinerators alone. Scrubbers
have a 99 percent efficiency in collecting particulates, but are practically ineffective in reducing car-
bon monoxide emissions. In naphthalene-based production, cyclones can be used to control catalyst
dust emissions with 90 to 98 percent efficiency.
Pretreatment and distillation emissions—particulates and hydrocarbons—are normally processed
through the water scrubber and/or incinerator used for the main process stream (reactor and con-
denser) or scrubbers alone, with the same efficiency percentages applying.
Product storage in the liquid phase results in small amounts of gaseous emissions. These gas
streams can either be sent to the main process vent gas control devices! or first processed through
sublimation boxes or devices used to recover escaped PAN. Flaking and bagging emissions are negli-
gible, but can be sent to a cyclone for recovery of PAN dust. Exhaust from the cyclone presents no
problem.
Table 5.12-1 gives emission factors for controlled and uncontrolled emissions from the production
of PAN.
5.12-2 EMISSION FACTORS 4/77
-------
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4/77
Chemical Process Industry
5.12-3
-------
5.12-4
EMISSION FACTORS
4/77
-------
Table 5.12-1. EMISSION FACTORS FOR PHTHALIC ANHYDRIDE1-8
EMISSION FACTOR RATING: B
Process
Oxidation of o-xylene°
Mam process stream0
Uncontrolled
W/scrubber and thermal
incinerator
W/thermal incinerator
W/mcinerator with
steam generator
Pretreatment
Uncontrolled
W/scrubber and thermal
incinerator
W/thermal incinerator
Distillation
Uncontrolled
W/scrubber and thermal
incinerator
W/thermal incinerator
Oxidation of naphthalene*3
Main process stream0
Uncontrolled
W/thermal incinerator
W/scrubber
Pretreatment
Uncontrolled
W/thermal incinerator
W/scrubber
Distillation
Uncontrolled
W/thermal incinerator
W/scrubber
Particulate
Ib/ton
138d
6
7
7
13*
0.5
0.7
89d
4
4
569.1
11
0.6
5h
1
<0.1
389
8
0.4
kg/MT
69d
3
4
4
6.4*
0.3
0.4
45^
2
2
289.'
6
0.3
2.5"
0.5
<0.1
199
4
0.2
SOX
Ib/ton
9.4e
9.4
9.4
9.4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
kg/MT
4.?e
4.7
4.7
4.7
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC
Ib/ton
0
0
0
0
0
0
0
2.4
<0.1
0.1
0
0
0
0
0
0
10
2
0.1
kg/MT
0
0
0
0
0
0
0
1.2
<0.1
<0.1
0
0
0
0
0
0
5
1
<0.1
CO
Ib/ton
301
12
15
15
0
0
0
0
0
0
100
20
100
0
0
0
0
0
0
kg/MT
151
6
8
8
0
0
0
0
0
0
50
10
50
0
0
0
0
0
0
aEmission factors are in units of pounds of pollutant per ton (kilogram of pollutant per metric ton) of phthalic anhydride
produced.
"Control devices listed are those currently being used by phthalic anhydride plants,
cMain process stream includes the reactor and multiple switch condensers as vented through the condenser unit.
Particulate consists of phthalic anhydride, maleic anhydride, and benzoic acid.
8Emissions change with catalyst age. Value shown corresponds to relatively fresh catalyst. Can be 19 to 25 Ib/ton (9.5 to 13
kg/MT) for aged catalyst.
Particulate consists of phthalic anhydride and maleic anhydride.
9Particulate consists of phthalic anhydride, maleic anhydride, and naphthaquinone.
Particulate is phthalic anhydride.
'Particulate does not include catalyst dust which is controlled by cyclones with an efficiency of 90 to 98 percent.
Reference for Section 5.12
1. Engineering and Cost Study of Air Pollution Control for the Petrochemical Industry. Vol 7:
Phthalic Anhydride Manufacture from Ortho-Xylene. Houdry Division, Air Products and Chemi-
cals, Inc., Marcus Hook, Pa. Prepared for Environmental Protection Agency, Research Triangle
Park, N.C. Publication No. EPA-450/3-73-006-g. July 1975.
4/77 Chemical Process Industry 5.12-5
-------
-------
5.13 PLASTICS
5.13.1 Process Description1
The manufacture of most resins or plastics begins with the polymerization or linking of the basic compound
(monomer), usually a gas or liquid, into high molecular weight noncrystalline solids. The manufacture of the
basic monomer is not considered part of the plastics industry and is usually accomplished at a chemical or
petroleum plant.
The manufacture of most plastics involves an enclosed reaction or polymerization step, a drying step, and a
final treating and forming step. These plastics are polymerized or otherwise combined in completely enclosed
stainless steel or glass-lined vessels. Treatment of the resin after polmerization varies with the proposed use.
Resins for moldings are dried and crushed or ground into molding powder. Resins such as the alkyd resins that are
to be used for protective coatings are normally transferred to an agitated thinning tank, where they are thinned
with some type of solvent and then stored in large steel tanks equipped with water-cooled condensers to prevent
loss of solvent to the atmosphere. Still other resins are stored in latex form as they come from the kettle.
5.13.2 Emissions and Controls1
The major sources of air contamination in plastics manufacturing are the emissions of raw materials or
monomers, emissions of solvents or other volatile liquids during the reaction, emissions of sublimed solids such as
phthalic anhydride in alkyd production, and emissions of solvents during storage and handling of thinned resins.
Emission factors for the manufacture of plastics are shown in Table 5.13-1.
Table 5.13-1. EMISSION FACTORS FOR PLASTICS
MANUFACTURING WITHOUT CONTROLS3
EMISSION FACTOR RATING: E
Type of plastic
Polyvinyl chloride
Polypropylene
Genera!
Part icu late
Ib/ton
35b
3
5 to 10
kg/MT
17.5b
1.5
2.5 to 5
Gases
Ib/ton
17C
0.7d
—
kg/MT
8.5C
0.35d
—
References 2 and 3
Usually controlled with a fabric filter efficiency of 98 to 99
percent
°As vinyl chloride.
dAs propylene.
Much of the control equipment used in this industry is a basic part of the system and serves to recover a
reactant or product. These controls include floating roof tanks or vapor recovery systems on volatile material,
storage units, vapor recovery systems (adsorption or condensers), purge lines that vent to a flare system, and
recovery systems on vacuum exhaust lines.
2/72
Chemical Process Industry
5.13-1
-------
References for Section 5.13
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Unpublished data from industrial questionnaire. U.S. DHEW, PHS, National Air Pollution Control
Administration, Division of Air Quality and Emissions Data. Durham, N.C. 1969. '
3. Private Communication between Resources Research, Incorporated, and Maryland State Department of
Health, Baltimore, Md. November 1969.
5.13-2 EMISSION FACTORS 2/72
-------
5.14 PRINTING INK
5.14.1 Process Description1
There are four major classes of printing ink: letterpress and lithographic inks, commonly called oil or paste
inks; and flexographic and rotogravure inks, which are referred to as solvent inks. These inks vary considerably in
physical appearance, composition, method of application, and drying mechanism. Flexographic and rotogravuic
inks have many elements in common with the paste inks but differ in that they are of very low viscosity, and they
almost always dry by evaporation of highly volatile solvents.2
There are three general processes in the manufacture of printing inks: (1) cooking the vehicle and adding dyes.
(2) grinding of a pigment into the vehicle using a roller mill, and (3) replacing water in the wet pigment pulp b>
an ink vehicle (commonly known as the flushing process).3 The ink "varnish" or vehicle is generally cooked in
large kettles at 200° to 600°F (93° to 315°C) for an average of 8 to 12 hours in much the same way that regular
varnish is made. Mixing of the pigment and vehicle is done in dough mixers or in large agitated tanks. Grinding is
most often carried out in three-roller or five-roller horizontal or vertical mills.
5.14.2 Emissions and Controls1-4
Varnish or vehicle preparation by heating is by far the largest source of ink manufacturing emissions. Cooling
the varnish components -- resins, drying oils, petroleum oils, and solvents - produces odorous emissions. At
about 350°F (175°C) the products begin to decompose, resulting in the emission of decomposition products
from the cooking vessel. Emissions continue throughout the cooking process with the maximum rate of emissions
occuring just after the maximum temperature has been reached. Emissions from the cooking phase can be
reduced by more than 90 percent with the use of scrubbers or condensers followed by afterburners.4-5
Compounds emitted from the cooking of olcoresmous varnish (resin plus varnish) include water vapor, fatty
acids, glycerine, acrolein, phenols, aldehydes, ketones, terpene oils, tcrpcnes, and carbon dioxide. Emissions of
thinning solvents used in flexographic and rotogravure inks may also occur.
The quantity, composition, and rate of emissions from ink manufacturing depend upon the cooking
temperature and time, the ingredients, the method of introducing additives, the degree of stirring, and the extent
of air or inert gas blowing. Particulate emissions resulting from the addition of pigments to the vehicle are
affected by the type of pigment and its particle si/e. Emission factors for the manufacture of printing ink aie
presented in Table 5.14-1.
2/72 Chemical Process Industry 5.14-1
-------
Table 5.14-1. EMISSION FACTORS FOR PRINTING INK
MANUFACTURING3
EMISSION FACTOR RATING: E
Type of process
Vehicle cooking
General
Oils
Oleoresinous
Alkyds
Pigment mixing
Gaseous organic13
Ib/ton
of product
120
40
150
160
-
kg/MT
of product
60
20
75
80
-
Particulates
Ib/ton
of pigment
—
_.
-
—
2
kg/MT
of pigment
—
-
-
-
1
aBased on data from section on pamt and varnish
Emitted as gas, but rapidly condense as the effluent is cooled.
References for Section 5.14
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Shreve, R. N. Chemical Process Industries, 3rd Ed. New York, McGraw Hill Book Co. 1967. p. 454-455.
3. Larsen, L.M. Industrial Printing Inks. New York, Reinhold Publishing Company. 1962.
4. Chatfield, H.E. Varnish Cookers. In: Air Pollution Engineering Manual. Danielson, J.A. (ed.). U.S. DHEW,
PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40. 1967. p.
688-695.
5. Private communication with Interchemical Corporation, Ink Division. Cincinnati, Ohio. November 10, 1969.
5.14-2
EMISSION FACTORS
2/72
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5.15 SOAP AND DETERGENTS
5.15.1 Soap Manufacture1
The manufacture of soap entails the catalytic hydrolysis of various fatty acids with sodium or potassium
hydroxide to form a glycerol-soap mixture. This mixture is separated by distillation, then neutralized and blended
to produce soap. The main atmospheric pollution problem in the manufacture of soap is odor. and. if a spray
drier is used, a particulate emission problem may also occur. Vent lines, vacuum exhausts, product and raw
material storage, and waste streams are all potential odor sources. Control of these odors may be achieved by
scrubbing all exhaust fumes and, if necessary, incinerating the remaining compounds. Odors emanating from the
spray drier may be controlled by scrubbing with an acid solution.
5.15.2 Detergent Manufacture1
I
The manufacture of detergents generally begins with the sulfuration by sulfuric acid of a fatty alcohol or linear
alkylate. The sulfurated compound is then neutralized with caustic solution (NaOH). and various dyes, perfumes.
and other compounds are added.2'3 The resulting paste or slurry is then sprayed under pressure into a vertical
drying tower where it is dried with a stream of hot air (400° to 500°F or 204° to 260°C). The dried detergent is
then cooled and packaged. The main source of particulate emissions is the spray-drying tower. Odors may also be
emitted from the spray-drying operation and from storage and mixing tanks. Particulate emissions from
spray-drying operations are shown in Table 5.15-1.
Table 5.15-1. PARTICULATE EMISSION FACTORS FOR
SPRAY-DRYING DETERGENTS3
EMISSION FACTOR RATING: B
Control device
Uncontrolled
Cyclone*5
Cyclone followed by:
Spray chamber
Packed scrubber
Venturi scrubber
Overall
efficiency, %
85
92
95
97
Particulate emissions
Ib/ton of
product
90
14
7
5
3
kg/MT of
product
45
7
3.5
2.5
1.5
aBased on analysis of data in References 2 through 6.
Some type of primary collector, such as a cyclone, is considered an
integral part of the spray-drying system.
2/72
Chemical Process Industry
5.15-1
-------
References for Section 5.15
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration, Durham, N.C., under Contract Number CPA--22-69-119. April 1970.
2. Phelps, A.H. Air Pollution Aspects of Soap and Detergent Manufacture. J. Air Pol. Control Assoc.
17(8):505-507, August 1967.
3. Shreve, R.N. Chemical Process Industries. 3rd Ed. New York, McGraw-Hill Book Company. 1967. p.
544-563.
4. Larsen, G.P., G.I. Fischer, and W.J. Hamming. Evaluating Sources of Air Pollution. Ind. Eng. Chem.
45:1070-1074, May 1953.
5. McCormick, P.Y., R.L. Lucas, and D.R. Wells. Gas-Solid Systems. In: Chemical Engineer's Handbook. Perry,
J.H. (ed.). New York, McGraw-Hill Book Company. 1963. p. 59.
6. Private communication with Maryland State Department of Health, Baltimore, Md. November 1969.
5.15-2 EMISSION FACTORS 2/72
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5.16 SODIUM CARBONATE (Soda Ash)
5.16.1 Process Description1
Soda ash is manufactured by three processes: (1) the natural or Lake Brine process, (2) the Solvay process
(ammonia-soda), and (3) the electrolytic soda-ash process. Because the Solvay process accounts for over 80
percent of the total production of soda ash, it will be the only one discussed in this section.
In the Solvay process, the basic raw materials are ammonia, coke, limestone (calcium carbonate), and salt
(sodium chloride). The salt, usually in the unpurified form of a brine, is first purified in a series of absorbers by
precipitation of the heavy metal ions with ammonia and carbon dioxide. In this process sodium bicarbonate is
formed. This bicarbonate coke is heated in a rotary kiln, and the resultant soda ash is cooled and conveyed to
storage.
5.16.2 Emissions
The major source of emissions from the manufacture of soda ash is the release of ammonia. Small amounts of
ammonia are emitted in the gases vented from the brine purification system. Intermittent losses of ammonia can
also occur during the unloading of tank trucks into storage tanks. The major sources of dust emissions include
rotary dryers, dry solids handling, and processing of lime. Dust emissions of fine soda ash also occur from
conveyor transfer points and air classification systems, as well as during tank-car loading and packaging. Emission
factors are summarized in Table 5.16-1.
Table 5.16-1. EMISSION FACTORS FOR SODA-ASH
PLANTS WITHOUT CONTROLS
EMISSION FACTOR RATING: D
Type of source
Ammonia recovery3-13
Conveying, transferring.
loading, etc.c
Particulates
Ib/ton
6
fkg/MT
3
Ammonia
Ib/ton
7
-
kg/MT
3.5
-
"Reference 2.
"Represents ammonia loss following the recovery system.
cBased on data in References 3 through 5.
2/72
Chemical Process Industry
5.16-1
-------
References for Section 5.16
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C.,under Contract Number CPA-22-69-119. April 1970.
2. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company. 1967. p.
225-230.
3. Facts and Figures for the Chemical Process Industries. Chem. Eng. News. 43:51-118 September 6, 1965.
4. Faith, W.L., D.B. Keyes, and R.L. Clark. Industrial Chemicals, 3rd Ed. New York, John Wiley and Sons, Inc.
1965.
5. Kaylor, F.B. Air Pollution Abatement Program of a Chemical Processing Industry. J. Air Pol. Control Assoc.
75:65-67, February 1965.
5.16-2 EMISSION FACTORS 2/72
-------
5.17 SULFURICACID Revised by William Vatavuk
and Donald Carey
5.17.1 Process Description
All sulfuric acid is made by either the lead chamber or the contact process. Because the contact process
accounts for more than 97 percent of the total sulfuric acid production in the United States, it is the only process
discussed in this section. Contact plants are generally classified according to the raw materials charged to them:
(1) elemental sulfur burning, (2) spent acid and hydrogen sulfide burning, and (3) sulfide ores and smelter gas
burning plants. The relative contributions from each type of plant to the total acid production are 68, 18.5, and
13.5 percent, respectively.
All contact processes incorporate three basic operations, each of which corresponds to a distinct chemical
reaction. First, the sulfur in the feedstock is burned to sulfur dioxide:
S + 02 —*- S02.
Sulfur Oxygen Sulfur (1)
dioxide
Then, the sulfur dioxide is catalytically oxidized to sulfur trioxide:
2S02 + 02 —»- 2S03.
Sulfur Oxygen Sulfur (2)
dioxide trioxide
Finally, the sulfur trioxide is absorbed in a strong, aqueous solution of sulfuric acid:
SO3 + H20 —-»- thSO4.
Sulfur Water Sutfuric
trioxide acid
5.17.1.1 Elemental Sulfur-Burning Plants1'2 - Elemental sulfur, such as Frasch-piocess sulfui from oil refineries,
is melted, settled, or filtered to remove ash and is fed into a combustion chamber. The sulfur is burned in clean
air that has been dried by scrubbing with 93 to 99 percent sulfuric acid. The gases from the combustion chamber
are cooled and then enter the solid catalyst (vanadium pentoxide) converter. Usually, 95 to 98 percent of the
sulfur dioxide from the combustion chamber is converted to sulfur trioxide, with an accompanying large
evolution of heat. After being cooled, the converter exit gas enters an absorption tower where the sulfur trioxide
is absorbed with 98 to 99 percent sulfuric acid. The sulfur trioxide combines with the water in the acid and forms
more sulfuric acid.
If oleum, a solution of uncombined S03 in FbSOzj, is produced, S03 from the converter is first passed to an
oleum tower that is fed with 98 percent acid from the absorption system. The gases from the oleum tower are
then pumped to the absorption column where the residual sulfur trioxide is removed.
A schematic diagram of a contact process sulfuric acid plant that burns elemental sulfur is shown in Figure
5.17-1.
4/73 Chemical Process Industry 5.17-1
-------
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CD
C
c
c
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o
o
ro
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o
o
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5.17-2
EMISSION FACTORS
4/73
-------
-SPENT ACID
•SULFUR
'FUEL OIL
so?
STRIPPER AIR
.\\\\\\>
BLOWER
TO
ATMOS-
PHERE
98% ACID
"PUMP TANK
Figure 5.17-2. Basic flow diagram of contact-process sulfuric acid plant burning spent acid.
4/73
Chemical Process Industry
5.17-3
-------
5.17.1.2 Spent Acid and Hydrogen Sulfide Burning Plants1'2 - Two types of plants are used to process this lype
of sulfuric acid. In one the sulfur dioxide and other combustion products from the combustion of spent acid
and/or hydrogen sulfide with undried atmospheric air are passed through gas-cleaning and mist-removal
equipment. The gas stream next passes through a drying tower. A blower draws the gas from the drying tower and
discharges the sulfur dioxide gas to the sulfur trioxide converter. A schematic diagram of a contact-process
sulfuric acid plant that burns spent acid is shown in Figure 5.17-2.
In a "wet-gas plant," the wet gases from the combustion chamber are charged directly to the converter with no
intermediate treatment. The gas from the converter flows to the absorber, through which 93 to 98 percent
sulfuric acid is circulating.
5.17.1.3 Sulfide Ores and Smelter Gas Plants - The configuration of this type of plant is essentially the same as
that of a spent-acid plant (Figure 5.17-2) with the primary exception that a roaster is used in place of the
combustion furnace.
The feed used in these plants is smelter gas, available from such equipment as copper converters, reverberatory
furnaces, roasters, and flash smelters. The sulfur dioxide in the gas is contaminated with dust, acid mist, and
gaseous impurities. To remove the impurities the gases must be cooled to essentially atmospheric temperature and
passed through purification equipment consisting of cyclone dust collectors, electrostatic dust and mist
precipitators, and scrubbing and gas-cooling towers. After the gases are cleaned and the excess water vapor is
removed, they are scrubbed with 98 percent acid in a drying tower. Beginning with the drying tower stage, these
plants are nearly identical to the elemental sulfur plants shown in Figure 5.17-1.
5.17.2 Emissions and Controls
5.17.2.1 Sulfur Dioxide1"3 - Nearly all sulfur dioxide emissions from sulfuric acid plants are found in the exit
gases. Extensive testing has shown that the mass of these SC>2 emissions is an inverse function of the sulfur
conversion efficiency (SC>2 oxidized to 803). This conversion is, in turn, affected by the number of stages in the
catalytic converter, the amount of catalyst used, the temperature and pressure, and the concentrations of the
reactants, sulfur dioxide and oxygen. For example, if the inlet SC>2 concentration to the converter were 8 percent
by volume (a representative value), and the conversion temperature were 473°C, the conversion efficiency would
be 96 percent. At this conversion, the uncontrolled emission factor for SC>2 would be 55 pounds per ton (27.5
kg/MT) of 100 percent sulfuric acid produced, as shown in Table 5.17-1. For purposes of comparison, note that
the Environmental Protection Agency performance standard3 for new and modified plants is 4 pounds per ton
(2kg / MT) of 100 percent acid produced, maximum 2-hour average. As Table 5.17-1 and Figure 5.17-3 indicate,
achieving this standard requires a conversion efficiency of 99.7 percent in an uncontrolled plant or the equivalent
S(>2 collection mechanism in a controlled facility. Most single absorption plants have SC'2conversion efficiencies
ranging from 95 to 98 percent.
In addition to exit gases, small quantities of sulfur oxides are emitted from storage tank vents and tank car and
tank truck vents during loading operations; from sulfuric acid concentrators; and through leaks in process
equipment. Few data are available on emissions from these sources.
Of the many chemical and physical means for removing S02 from gas streams, only the dual absorption and
the sodium sulfite-bisulfite scrubbing processes have been found to increase acid production without yielding
unwanted by-products.
5.17-4 EMISSION FACTORS 4/73
-------
Table 5.17-1. EMISSION FACTORS FOR SULFURIC
ACID PLANTS3
EMISSION FACTOR RATING: A
Conversion of S02
to SO3, %
93
94
95
96
97
98
99
99.5
99.7
100
SO 2 emissions
Ib/tonof 100%
H2S04
96
82
70
55
40
27
14
7
4
0
kg/MTof 100%
H2S04
48.0
41.0
35.0
27.5
20.5
13.0
7.0
3.5
2.0
0.0
Reference 1.
bThe following linear interpolation formula can be used for
calculating emission factors for conversion efficiencies between 93
and 100 percent: emission factor (Ib/ton acid) =-13.65 (percent
conversion efficiency) + 1365.
In the dual absorption process, the 863 gas formed in the primary converter stages is sent to a primary
absorption tower where J^SC^ is formed. The remaining unconverted sulfur dioxide is forwarded to the final
stages in the converter, from whence it is sent to the secondary absorber for final sulfur trioxide removal. The
result is the conversion of a much higher fraction of SC>2 to 863 (a conversion of 99.7 percent or higher, on the
average, which meets the performance standard). Furthermore, dual absorption permits higher converter inlet
sulfur dioxide concentrations than are used in single absorption plants because the secondary conversion stages
effectively remove any residual sulfur dioxide from the primary absorber.
Where dual absorption reduces sulfur dioxide emissions by increasing the overall conversion efficiency, the
sodium sulfite-bisulfite scrubbing process removes sulfur dioxide directly from the absorber exit gases. In one
version of this process, the sulfur dioxide in the waste gas is absorbed in a sodium sulfite solution, separated, and
recycled to the plant. Test results from a 750 ton (680 MT) per day plant equipped with a sulfite scrubbing
system indicated an average emission factor of 2.7 pounds per ton (1.35 kg/MT).
15.17.2.2 Acid Mist1"3 - Nearly all the acid mist emitted from sulfuric acid manufacturing can be traced to the
absorber exit gases. Acid mist is created when sulfur trioxide combines with water vapor at a temperature below
the dew point of sulfur trioxide. Once formed within the process system, this mist is so stable that only a small
quantity can be removed in the absorber.
In general, the quantity and particle size distribution of acid mist are dependent on the type of sulfur
feedstock used, the strength of acid produced, and the conditions in the absorber. Because it contains virtually no
water vapor, bright elemental sulfur produces little acid mist when burned; however, the hydrocarbon impurities
in other feedstocks - dark sulfur, spent acid, and hydrogen sulfide — oxidize to water vapor during combustion.
The water vapor, in turn, combines with sulfur trioxide as the gas cools in the system.
4/73
Chemical Process Industry
5.17-5
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99.92
10,000
SULFUR CONVERSION, % feedstock sulfur
99.7 99.0
97.0 96.0 95.0 92.9
1.5 2 2.5 3 4 5 6 7 8 9 10 15 20 25 30 40 50 60708090100
S02EMISSIONS, Ib/ton of 100% H2S04 produced
Figure 5.17-3. Sulfuric acid plant feedstock sulfur conversion versus volumetric and
mass SC>2 emissions at various inlet S02 concentrations by volume.
5.17-6
EMISSION FACTORS
4/73
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The strength of acid produced-whether oleum or 99 percent sulfuric acid-also affects mist emissions. Oleum
plants produce greater quantities of finer, more stable mist. For example, uncontrolled mist emissions from
oleum plants burning spent acid range from 0.1 to 10.0 pounds per ton (0.05 to 5.0 kg/MX), while those from 98
percent acid plants burning elemental sulfur range from 0.4 to 4.0 pounds per ton (0.2 to 2.0 kg/MT).
Furthermore, 85 to 95 weight percent of the mist particles from oleum plants are less than 2 microns in diam-
eter, compared with only 30 weight percent that are less than 2 microns in diameter from 98 percent acid plants.
The operating temperature of the absorption column directly affects sulfur trioxide absorption and,
accordingly, the quality of acid mist formed after exit gases leave the stack. The optimum absorber operating
temperature is dependent on the strength of the acid produced, throughput rates, inlet sulfur trioxide
concentrations, and other variables peculiar to each individual plant. Finally, it should be emphasized that the
percentage conversion of sulfur dioxide to sulfur trioxide has no direct effect on u:id mist emissions. In Table
5.17-2 uncontrolled acid mist emissions are presented for various sulfuric acid plants.
Two basic types of devices, electrostatic precipitators and fiber mist eliminators, effectively reduce the acid
mist concentration from contact plants to less than the EPA new-source performance standard, which is 0.15
pound per ton (0.075 kg/MT) of acid. Precipitators, if properly maintained, are effective in collecting the mist
particles at efficiencies up to 99 percent (see Table 5.17-3).
The three most commonly used fiber mist eliminators are the vertical tube, vertical panel, and horizontal
dual-pad types. They differ from one another in the arrangement of the fiber elements, which are composed of
either chemically resistant glass or fluorocarbon, and in the means employed to collect the trapped liquid. The
operating characteristics of these three types are compared with electrostatic precipitators in Table 5.17-3.
Table 5.17-2. ACID MIST EMISSION FACTORS FOR SULFURIC
ACID PLANTS WITHOUT CONTROLS3
EMISSION FACTOR RATING: B
Raw material
Recovered sulfur
Bright virgin sulfur
Dark virgin sulfur
Sulfide ores
Spent acid
Oleurn produced,
% total output
Oto 43
0
33 to 100
Oto 25
Oto 77
Emissions'3
Ib/ton acid
0.35 to 0.8
1.7
0.32 to 6.3
1.2 to 7.4
2.2 to 2.7
kg/MT acid
0.1 75 to 0.4
0.85
0.16 to 3.15
0.6 to 3.7
1.1 to 1.35
Reference 1.
Emissions are proportional to the percentage of oleum in the total product. Use
the low end of ranges for low oleum percentage and high end of ranges for high
oleum percentage.
4/73
Chemical Process Industry
5.17-7
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Table 5.17-3. EMISSION COMPARISON AND COLLECTION EFFICIENCY OF TYPICAL
ELECTROSTATIC PRECIPITATOR AND FIBER MIST ELIMINATORS"
Control device
Electrostatic
precipitator
Fiber mist eliminator
Tubular
Panel
Dual pad
Particle size
collection efficiency, %
>3^m
99
100
100
100
<3nm
100
95 to 99
90 to 98
93 to 99
Acid mist emissions
98% acid plants0
Ib/ton
0.10
0.02
0.10
0.11
kg/MT
0.05
0.01
0.05
0.055
oleum plants
Ib/ton
0.12
0.02
0.10
0.11
kg/MT
0.06
0.01
0.05
0.055
Reference 2.
Based on manufacturers' generally expected results; calculated for 8 percent sulfur dioxide
concentration in gas converter.
References for Section 5.17
1. Atmospheric Emissions from Sulfuric Acid Manufacturing Processes. U.S. DHEW, PHS, National Air
Pollution Control Administration. Washington, D.C. Publication Number 999-AP-13. 1966.
2. Unpublished report on control of air pollution from sulfuric acid plants. Environmental Protection Agency.
Research Triangle Park, N.C. August 1971.
3. Standards of Performance for New Stationary Sources. Environmental Protection Agency. Washington, D.C.
Federal Register. 36(247): December 23, 1971.
5.17-8
EMISSION FACTORS
4/73
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5.18 SULFUR By William Vatavuk
5.18.1 Process Description
Nearly all of the elemental sulfur produced from hydrogen sulfide is made by the modified Claus process.
The process (Figure 5.18-1) consists of the multi-stage oxidation of hydrogen sulfide according to the following
reaction:
2H2S + O2 >• 2S + 2H2O
Hydrogen Oxygen Sulfur Water
sulfide
In the first step, approximately one-third of the hydrogen sulfide is reacted with air in a pressurized boiler (1.0
to 1.5 atmosphere) where most of the heat of reaction and some of the sulfur are removed. After removal of the
water vapor and sulfur, the cooled gases are heated to between 400 and 500°F, and passed over a "Claus" catalyst
bed composed of bauxite or alumina, where the reaction is completed. The degree of reaction conpletion is a
function of the number of catalytic stages employed. Two stages can recover 92 to 95 percent of the potential
sulfur; three stages, 95 to 96 percent; and four stages, 96 to 97 percent. The conversion to sulfur is ultimately
limited by the reverse reaction in which water vapor recombines with sulfur to form gaseous hydrogen sulfide and
sulfur dioxide. Additional amounts of sulfur are lost as vapor, entrained mist, or droplets and as carbonyl sulfide
and carbon disulfide (0.25 to 2.5 percent of the sulfur fed). The latter two compounds are formed in the
pressurized boiler at high temperature (1500 to 2500°F) in the presence of carbon compounds.
The plant tail gas, containing the above impurities in volume quantities of 1 to 3 percent, usually passes to an
incinerator, where all of the sulfur is oxidized to sulfur dioxide at temperatures ranging from 1000 to 1200 F.
The tail gas containing the sulfur dioxide then passes to the atmosphere via a stack.
5.18.2 Emissions and Controls1'2
Virtually all of the emissions from sulfur plants consist of sulfur dioxide, the main incineration product. The
quantity of sulfur dioxide emitted is, in turn, a function of the number of conversion stages employed, the
process temperature and pressure, and the amounts of carbon compounds present in the pressurized boiler.
The most commonly used control method involves two main steps - conversion of sulfur dioxide to hydrogen
sulfide followed by the conversion of hydrogen sulfide to elemental sulfur. Conversion of sulfur dioxide to
hydrogen sulfide occurs via catalytic hydrogenation or hydrolysis at temperatures from 600 to 700°F. The
products are cooled to remove the water vapor and then reacted with a sodium carbonate solution to yield
sodium hydrosulfide. The hydrosulfide is oxidized to sulfur in solution by sodium vanadate. Finely divided sulfur
appears as a froth that is skimmed off, washed, dried by centrifugation, and added to the plant product. Overall
recovery of sulfur approaches 100 percent if this process is employed. Table 5.18-1 lists emissions from
controlled and uncontrolled sulfur plants.
4/73 Chemical Process Industry 5.18-1
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CLEAN GAS
SOUR
GAS
COOLER
COOLER
REACTIVATOR
HEAT
EXCHANGER
GAS PURIFICATION-
H2S, S02, C02, N2, H20
I
AIR
BOILER
S
CONVERTER
STACK
CONVERTER
SCRUBBER
SCRUBBER
SULFUR CONVERSION
(CLAUS SECTION)
Figure 5.18-1. Basic flow diagram of modified Glaus process with two converter stages
used in manufacturing sulfur.
Table 5.18-1. EMISSION FACTORS FOR MODIFIED-CLAUS
SULFUR PLANTS EMISSION FACTOR RATING: D
Number of
catalytic stages
Two, uncontrolled
Three, uncontrolled
Four, uncontrolled
Sulfur removal process
Recovery of
of sulfur,%
92 to 95
95 to 96
96 to 97
99.9
SO2 emissions3
Ib/ton
100% sulfur
21 1 to 348
167 to 211
124 to 167
4.0
kg/MT
100% sulfur
106 to 162
84 to 1 06
62 to 84
2.0
aThe range in emission factors corresponds to the range in the percentage recovery of
sulfur.
References for Section 5.18
1. Beavon, David K. Abating Sulfur Plant Tail Gases. Pollution Engineering. 4(l):34-35. January 1972.
2. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 19. New York, John Wiley and Sons, Inc. 1969.
5.18-2
EMISSION FACTORS
4/73
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5.19 SYNTHETIC FIBERS
5.19.1 Process Description1
Synthetic fibers are classified into two major categories, semi-synthetic and "true" synthetic. Semi-synthetics,
such as viscose rayon and acetate fibers, result when natural polymeric materials such as cellulose are brought into
a dissolved or dispersed state and then spun into fine filaments. True synthetic polymers, such as Nylon, * Orion,
and Dacron, result from addition and other polymerization reactions that form long chain molecules.
True synthetic fibers begin with the preparation of extremely long, chain-like molecules. The polymer is spun
in one of four ways:^ (1) melt spinning, in which molten polymer is pumped through spinneret jets, the polymer
solidifying as it strikes the cool air; (2) dry spinning, in which the polymer is dissolved in a suitable organic
solvent, and the resulting solution is forced through spinnerets; (3) wet spinning, in which the solution is
coagulated in a chemical as it emerges from the spinneret; and (4) core spinning, the newest method, in which a
continuous filament yarn together with short-length "hard" fibers is introduced onto a spinning frame in such a
way as to form a composite yarn.
5.19.2 Emissions and Controls1
In the manufacture of viscose rayon, carbon disulfide and hydrogen sulfide are the major gaseous emissions.
Air pollution controls are not normally used to reduce these emissions, but adsorption in activated carbon at an
efficiency of 80 to 95 percent, with subsequent recovery of the €82 can be accomplished.3 Emissions of gaseous
hydrocarbons may also occur from the drying of the finished fiber. Table 5.19-1 presents emission factors for
semi-synthetic and true synthetic fibers.
Table 5.19-1. EMISSION FACTORS FOR SYNTHETIC FIBERS MANUFACTURING
EMISSION FACTOR RATING: E
Type of fiber
Semi-synthetic
Viscose rayona'b
True synthetic0
Nylon
Dacron
Hydrocarbons
Ib/ton
-
7
—
kg/MT
-
3.5
—
Carbon
disulfide
Ib/ton
55
-
—
kg/MT
27.5
-
—
Hydrogen
sulfide
Ib/ton
6
-
—
kg/MT
3
-
—
Oil vapor
or mist
Ib/ton
—
15
7
kg/MT
—
7.5
3.5
aReference 4.
^IVIay be reduced by 80 to 95 percent adsorption in activated charcoal.
cReference 5.
*Mention of company or product names does not constitute endorsement by the Environmental Protection
Agency.
2/72
Chemical Process Industry
5.19-1
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References for Section 5.19
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Fibers, Man-Made. In: Kirk-Othmer Encyclopedia of Chemical Technology. New York, John Wiley and Sons,
Inc. 1969.
3. Fluidized Recovery System Nabs Carbon Disulfide. Chem. Eng. 70(8):92-94. April 15, 1963.
4. Private communication between Resources Research, Incorporated, and Rayon Manufacturing Plant.
December 1969.
5. Private communication between Resources Research, Incorporated, and E.I. Dupont de Nemours and
Company. January 13, 1970.
5.19-2 EMISSION FACTORS 2/72
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5.20 SYNTHETIC RUBBER
5.20.1 Process Descriptionl
Copolymers of butadiene and styrene, commonly known as SBR, account for more than 70 percent of all
synthetic rubber produced in the United States. In a typical SBR manufacturing process, the monomers of
butadiene and styrene are mixed with additives such as soaps and mercaptans. The mixture is polymerized to a
conversion point of approximately 60 percent. After being mixed with various ingredients such as oil and carbon
black, the latex product is coagulated and precipitated from the latex emulsion. The rubber particles are then
dried and baled.
5.20.2 Emissions and Controls1
Emissions from the synthetic rubber manufacturing process consist of organic compounds (largely the
monomers used) emitted from the reactor and blow-down tanks, and particulate matter and odors from the
drying operations.
Drying operations are frequently controlled with fabric filter systems to recover any particulate emissions,
which represent a product loss. Potential gaseous emissions are largely controlled by recycling the gas stream back
to the process. Emission factors from synthetic rubber plants are summarized in Table 5.20-1.
Table 5.20-1. EMISSION FACTORS FOR
SYNTHETIC RUBBER PLANTS: BUTADIENE-
ACRYLONITRILE AND BUTADIENE-STYRENE
EMISSION FACTOR RATING: E
Compound
Alkenes
Butadiene
Methyl propene
Butyne
Pentadiene
Alkanes
Dime thy Iheptane
Pentane
Ethanenitrile
Carbonyls
Acrylonitrile
Acrolein
Emissions3'13
Ib/ton
40
15
3
1
1
2
1
17
3
kg/MT
20
7.5
1.5
0.5
0.5
1
0.5
8.5
1.5
aThe butadiene emission is not continuous and is
greatest right after a batch of partially polymerized
latex enters the blow-down tank.
bReferences 2 and 3.
2/72
Chemical Process Industry
5.20-1
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References for Section 5.20
1. Air Pollutant Emission Factors. Final Report. Resources Research Inc. Reston, Va. Prepared for National Air
Pollution Control Administration. Durham. N.C., under Contract Number CF'A-22-69-119. April 1970.
2. The Louisville Air Pollution Study. U.S. DHEW, PHS, Division of Air Pollution. Cincinnati, Ohio. 1961. p.
26-27 and 124.
3. Unpublished data from synthetic rubber plant. U.S. DHEW, PHS, EHS, National Air Pollution Control
Administration, Division of Air Quality and Emissions Data. Durham, N.C. 1969.
5.20-2 EMISSION FACTORS 2/72
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5.21 TEREPHTHALIC ACID
5.21.1 Process Description1'2
The main use of terephthalic acid is to produce dimethylterephthalate, which is used for polyester fibers (like
Dacron) and films. Terephthalic acid can be produced in various ways, one of which is the oxidation of/J-xylene
by nitric acid. In this process an oxygen-containing gas (usually air), p-xylene, and HN03 are all passed into a
reactor where oxidation by the nitric acid takes place in two steps. The first step yields primarily ^O; the second
step yields mostly NO in the offgas. The terephthalic acid precipitated from the reactor effluent is recovered by
conventional crystallization, separation, and drying operations.
5.21.2 Emissions
The NO in the offgas from the reactor is the major air contaminant from the manufacture of terephthalic acid.
The amount of nitrogen oxides emitted is roughly estimated in Table 5.21-1.
Table 5.21-1. NITROGEN OXIDES
EMISSION FACTORS FOR
TEREPHTHALIC ACID PLANTS3
EMISSION FACTOR RATING: D
Type of operation
Reactor
Nitrogen oxides
(NO)
Ib/ton
13
kg/MT
65
aReference 2.
References for Section 5.21
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C. under Contract Number CPA-22-69-119. April 1970.
2. Terephthalic Acid. In. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 9. New York, John Wiley
and Sons, Inc. 1964.
2/72 Chemical Process Industry 5.21-1
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6. FOOD AND AGRICULTURAL INDUSTRY
Before food and agricultural products are used by the consumer they undergo a number of processing steps,
such as refinement, preservation, and product improvement, as well as storage and handling, packaging, and
shipping. This section deals with the processing of food and agricultural products and the intermediate steps that
present air pollution problems. Emission factors are presented for industries where data were available. The
primary pollutant emitted from these processes is particulate matter.
6.1 ALFALFA DEHYDRATING by Tom Lahre
6.1.1 General13
Dehydrated alfalfa is a meal product resulting from the rapid drying of alfalfa by artifical means at
temperatures above 212°F (100°C). Alfalfa meal is used in chicken rations, cattle feed, hog rations, sheep feed,
turkey mash, and other formula feeds. It is important for its protein content, growth and reproductive factors,
pigmenting xanthophylls, and vitamin contributions.
A schematic of a generalized alfalfa dehydrator plant is given in Figure 6.1-1. Standing alfalfa is mowed and
chopped in the field and transported by truck to a dehydrating plant, which is usually located within 10 miles of
the field. The truck dumps the chopped alfalfa (wet chops) onto a self-feeder, which carries it into a direct-fired,
rotary drum. Within the drum, the wet chops are dried from an initial moisture content of about 60 to 80 percent
(by weight) to about 8 to 16 percent. Typical combustion gas temperatures within the oil- or gas-fired drums
range from 1800 to 2000°F (980 to 1092°C) at the inlet to 250 to 300°F (120 to 150°C) at the outlet.
From the drying drum, the dry chops are pneumatically conveyed into a primary cyclone that separates them
from the high-moisture, high-temperature exhaust stream. From the primary cyclone, the chops are fed into a
hammermill, which grinds the dry chops into a meal. The meal is pneumatically conveyed from the hammermill
into a meal collector cyclone in which the meal is separated from the airstream and discharged into a holding bin.
Meal is then fed into a pellet mill where it is steam conditioned and extruded into pellets.
From the pellet mill, the pellets are either pneumatically or mechanically conveyed to a cooler, through which
air is drawn to cool the pellets and, in some cases, remove fines. Fines removal is more commonly effected in
shaker screens following or ahead of the cooler, with the fines being conveyed back into the meal collector
cyclone, meal bin, or pellet mill. Cyclone separators may be employed to separate entrained fines in the cooler
exhaust and to collect pellets when the pellets are pneumatically conveyed from the pellet mill to the cooler.
Following cooling and screening, the pellets are transferred to bulk storage. Dehydrated alfalfa is most often
stored and shipped in pellet form; however, in some instances, the pellets may be ground in a hammermill and
shipped in meal form. When the finished pellets or ground pellets are pneumatically transferred to storage or
loadout, additional cyclones may be employed for product airstream separation at these locations.
6.1.2 Emissions and Controls*"3
Particulate matter is the primary pollutant of concern from alfalfa dehydrating plants although some odors
arise from the organic volatiles driven off during drying. Although the major source is the primary cooling
cyclone, lesser sources include the downstream cyclone separators and the bagging and loading operations.
4/76 6.1-1
-------
Emission factors for the various cyclone separators utilized in alfalfa dehydrating plants are given in Table
6.1-1. Note that, although these sources are common to many plants, there will be considerable variation from
the generalized flow diagram in Figure 6.1-1 depending on the desired nature of the product, the physical layout
of the plant, and the modifications made for air pollution control. Common variations include ducting the
exhaust gas stream from one or more of the downstream cyclones back through the primary cyclone and ducting
a portion of the primary cyclone exhaust back into the furnace. Another modification involves ducting a part of
the meal collector cyclone exhaust back into the hammermill, with the remainder ducted to the primary cyclone
or discharged directly to the atmosphere. Also, additional cyclones may be employed if the pellets are
pneumatically rather than mechanically conveyed from the pellet mill to the cooler or if the finished pellets or
ground pellets are pneumatically conveyed to storage or loadout.
Table 6.1-1. PARTICULATE EMISSION FACTORS FOR ALFALFA DEHYDRATING PLANTS
EMISSION FACTOR RATING: PRIMARY CYCLONES: A
ALL OTHER SOURCES: C
Sources3
Primary cyclone
Meal collector cyclone^
Pellet collector cyclone6
Pellet cooler cyclone'
Pellet regrind cycloneS
Storage bin cyclone'1
Emissions
Ib/ton of product"3
10C
2.6
Not available
3
8
Neg.
kg/MT of product'3
5C
1.3
Not available
1.5
4
Neg.
aThe cyclones used for product/airstream separation are the air pollution sources in alfalfa dehydrating plants.
All factors are based on References 1 and 2.
Product consists of meal or pellets. These factors can be applied to the quantity of incoming wet chops by
dividing by a factor of four.
cThis average factor may be used even when other cyclone exhaust streams are ducted back into the primary
cyclone. Emissions from primary cyclones may range from 3 to 35 Ib/ton (1.5 to 17.5 kg/MT) of product
and are more a function of the operating procedures and process modifications made for air pollution control
than whether other cyclone exhausts are ducted back through the primary cyclone. Use 3 to 15 Ib/ton (1.5 to
7.5 kg/MT) for plants employing good operating procedures and process modifications for air pollution control.
Use higher values for older, unmodified, or less well run plants.
This cyclone is also called the air meal separator or hammermill cyclone. When the meal collector exhaust is
ducted back to the primary cyclone and/or the hammermill, this cyclone is no longer a source,
^his cyclone will only be present if the pellets are pneumatically transferred from the P'ellet mill to the pellet
cooler.
This cyclone is also called the pellet meal air separator or pellet mill cyclone. When the pellet cooler cyclone
exhaust is ducted back into the primary cyclone, it is no longer a source.
^This cyclone is also called the pellet regrind air separator. Regrind operations are more commonly found at
terminal storage facilities than at dehydrating plants.
Small cyclone collectors may be used to collect the finished pellets when they are pneumatically transferred
to storage.
Air pollution control (and product recovery) is accomplished in alfalfa dehyarating plants in a variety of ways.
A simple, yet effective technique is the proper maintenance and operation of the alfalfa dehydrating equipment.
Particulate emissions can be reduced significantly if the feeder discharge rates are uniform, if the dryer furnace is
operated properly, if proper airflows are employed in the cyclone collectors, and if the hammermill is well
maintained and not overloaded. It is especially important in this regard not to overdry and possibly burn the
chops as this results in the generation of smoke and increased fines in the grinding and pelletizing operations.
6.1-2
EMISSION FACTORS
4/76
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c
co
c
o
CD
•a
42
CO
_
O
4—
-a
OJ
N
0}
C
a>
CD
O)
4/76
Food and Agricultural Industry
6.1-3
-------
Equipment modification provides another means of particulate control. Existing cyclones can be replaced with
more efficient cyclones and concomitant air flow systems. In addition, the furnace and burners can be modified
or replaced to minimize flame impingement on the incoming green chops. In plants where the hammermill is a
production bottleneck, a tendency exists to overdry the chops to increase throughput, which results in increased
emissions. Adequate hammermill capacity can reduce this practice.
Secondary control devices can be employed on the cyclone collector exhaust streams. Generally, this practice
has been limited to the installation of secondary cyclones or fabric filters on the meal collector, pellet collector,
or pellet cooler cyclones. Some measure of secondary control can also be effected on these cyclones by ducting
their exhaust streams back into the primary cyclone. Primary cyclones are not controlled by fabric filters because
of the high moisture content in the resulting exhaust stream. Medium energy wet scrubbers are effective in
reducing particulate emissions from the primary cyclones, but have only been installed al a few plants.
Some plants employ cyclone effluent recycle systems for particulate control. One system skims off the
particulate-laden portion of the primary cyclone exhaust and returns it to the furnace for incineration. Another
system recycles a large portion of the meal collector cyclone exhaust back to the hammermill. Both systems can
be effective in controlling particulates but may result in operating problems, such as condensation in the recycle
lines and plugging or overheating of the hammermill.
References for Section 6.1
1. Source information supplied by Ken Smith of the American Dehydrators Association, Mission, Kan.
December 1975.
2. Gorman, P.G. et al. Emission Factor Development for the Feed and Grain Industry. Midwest Research
Institute. Kansas City, Mo. Prepared for Environmental Protection Agency, Research Triangle Park, N.C.
under Contract No. 68-02-1324. Publication No. EPA450/3-75-054. October 1974.
3. Smith, K.D. Particulate Emissions from Alfalfa Dehydrating Plants - Control Costs and Effectiveness. Final
Report. American Dehydrators Association. Mission, Kan. Prepared for Environmental Protection Agency,
Research Triangle Park, N.C. Grant No. R801446. Publication No. 650/2-74-007. January 1974.
6.1-4 EMISSION FACTORS 4/76
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6.2 COFFEE ROASTING
6.2.1 Process Descriptionl >2
Coffee, which is imported in the form of green beans, must be cleaned, blended, roasted, and packaged before
being sold. In a typical coffee roasting operation, the green coffee beans are freed of dust and chaff by dropping
the beans into a current of air. The cleaned beans are then sent to a batch or continuous roaster. During the
roasting, moisture is driven off, the beans swell, and chemical changes take place that give the roasted beans their
typical color and aroma. When the beans have reached a certain color, they are quenched, cooled, and stoned.
6.2.2 Emissions1'2
Dust, chaff, coffee bean oils (as mists), smoke, and odors are the principal air contaminants emitted from
coffee processing. The major source of particulate emissions and practically the only source of aldehydes,
nitrogen oxides, and organic acids is the roasting process. In a direct-fired roaster, gases are vented without
recirculation through the flame. In the indirect-fired roaster, however, a portion of the roaster gases are
recirculated and particulate emissions are reduced. Emissions of both smoke and odors from the roasters can be
almost completely removed by a properly designed afterburner.1 >2
Particulate emissions also occur from the stoner and cooler. In the stoner, contaminating materials heavier
than the roasted beans are separated from the beans by an air stream. In the cooler, quenching the hot roasted
beans with water causes emissions of large quantities of steam and some particulate matter.3 Table 6.2-1
summarizes emissions from the various operations involved in coffee processing.
Table 6.2-1. EMISSION FACTORS FOR ROASTING PROCESSES WITHOUT CONTROLS
EMISSION FACTOR RATING: B
Type of process
Roaster
Direct-fired
Indirect-fired
Stoner and cooler0
Instant coffee spray dryer
Pollutant
Particulates8
Ib/ton
7.6
4.2
1.4
1.4d
kg/MT
3.8
2.1
0.7
0.7d
N0xb
Ib/ton
0.1
0.1
_
-
kg/MT
0.05
0.05
_
-
Aldehydes6
Ib/ton
0.2
0.2
—
-
kg/MT
0.1
0.1
_
-
Organic acidsb
Ib/ton
0.9
0.9
—
-
kg/MT
0.45
0.45
_
-
aReference 3.
"Reference 1.
clf cyclone is used, emissions can be reduced by 70 percent.
"Cyclone plus wet scrubber always used, representing a controlled factor
2/72
Food and Agricultural Industry
6.2-1
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References for Section 6.2
1. Polglase, W.L., H.F. Dey, and R.T. Walsh. Coffee Processing. In: Air Pollution Engineering Manual.
Danielson, J.A. (ed.). U.S. DHEW, PHS, National Center for Air Pollution Control. Cincinnati, Ohio.
Publication Number 999-AP-40. 1967. p. 746-749.
2. Duprey, R.L. Compilation of Air Pollutant Emission Factors. U.S. DHEW, PHS, National Center for Air
Pollution Control. Durham, N.C. PHS Publication Number 999-AP-42. 1968. p. 19-20.
3. Partee, F. Air Pollution in the Coffee Roasting Industry. Revised Ed. U.S. DHEW, PHS, Division of Air
Pollution. Cincinnati, Ohio. Publication Number 999-AP-9. 1966.
6.2-2 EMISSION FACTORS 2/72
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6.3 COTTON GINNING
6.3.1 General1
The primary function of a cotton gin is to take raw seed cotton and separate the seed and the lint. A large
amount of trash is found in the seed cotton, and it must also be removed. The problem of collecting and
disposing of gin trash is two-fold. The first problem consists of collecting the coarse, heavier trash such as burrs,
sticks, stems, leaves, sand, and dirt. The second problem consists of collecting the finer dust, small leaf particles,
and fly lint that are discharged from the lint after the fibers are removed from the seed. From 1 ton (0.907 MT)
of seed cotton, approximately one 500-pound (226-kilogram) bale of cotton can be made.
6.3.2 Emissions and Controls
The major sources of particulates from cotton ginning include the unloading fan, the cleaner, and the stick and
burr machine. From the cleaner and stick and burr machine, a large percentage of the particles settle out in the
plant, and an attempt has been made in Table 6.3-1 to present emission factors that take this into consideration.
Where cyclone collectors are used, emissions have been reported to be about 90 percent less.1
Table 6.3-1. EMISSION FACTORS FOR COTTON GINNING OPERATIONS
WITHOUT CONTROLS8'5
EMISSION FACTOR RATING: C ''
Process
Unloading fan
Cleaner
Stick and burr
machine
Miscellaneous
Total
Estimated total
particulates
Ib/bale
5
1
3
3
12
kg/bale
2.27
0.45
1.36
1.36
5.44
Particles > 100jum
settled out, %
0
70
95
50
—
Estimated
emission factor
(released to
atmosphere)
Ib/bale
5.0
0.30
0.20
1.5
7.0
kg/bale
2.27
0.14
0.09
0.68
3.2
References 1 and 2.
One bale weighs 500 pounds (226 kilograms).
References for Section 6.3
1. Air-Borne Particulate Emissions from Cotton Ginning Operations. U.S. DHEW, PHS, Tail Sanitary
Engineering Center. Cincinnati, Ohio. 1960.
2. Control and Disposal of Cotton Ginning Wastes. A Symposium Sponsored by National Center for Air
Pollution Control and Agricultural Research Service, Dallas, Texas. May 1966.
2/72
Food and Agricultural Industry
6.3-1
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6.4 FEED AND GRAIN MILLS AND ELEVATORS
6.4.1 General1"3
Grain elevators are buildings in which grains are gathered, stored, and discharged for use, further
processing, or shipping. They are classified as "country," "terminal," and "export" elevators, according
to their purpose and location. At country elevators, grains are unloaded, weighed, and placed in
storage as they are received from farmers residing within about a 20-mile radius of the elevator. In
addition, country elevators sometimes dry or clean grain before it is shipped to terminal elevators or
processors.
Terminal elevators receive most of their grain from country elevators and ship to processors, other
terminals, and exporters. The primary functions of terminal elevators are to store large quantities of
grain without deterioration and to dry, clean, sort, and blend different grades of grain to meet buyer
specifications.
Export elevators are similar to terminal elevators except that they mainly load grain on ships for
export.
Processing of grain in mills and feed plants ranges from very simple mixing steps to complex
industrial processes. Included are such diverse processes as: (1) simple mixing operations in feed mills,
(2) grain milling in flour mills, (3) solvent extracting in soybean processing plants, and (4) a complex
series of processing steps in a corn wet-milling plant.
6.4.2 Emissions and Controls
Grain handling, milling, and processing include a variety of operations from the initial receipt of
the grain at either a country or terminal elevator to the delivery of a finished product. Flour, livestock
feed, soybean oil, and corn syrup are among the products produced from plants in the grain and feed
industry. Emissions from the feed and grain industry can be separated into two general areas, those
occurring at grain elevators and those occurring at grain processing operations.
6.4.2.1 Grain Elevators - Grain elevator emissions can occur from many different operations in the
elevator including unloading (receiving), loading (shipping), drying, cleaning, headhouse (legs),
tunnel belt, gallery belt, and belt trippers. Emission factors for these operations at terminal, country,
and export elevators are presented in Table 6.4-1. All of these emission factors are approximate average
values intended to reflect a variety of grain types. Actual emission factors for a specific source may be
considerably different, depending on the type of grain, i.e., corn, soybeans, wheat, and other factors
such as grain quality.
The emission factors shown in Table 6.4-1 represent the amount of dust generated per ton of grain
processed through each of the designated operations (i.e., uncontrolled emission factors). Amounts of
grain processed through each of these operations in a given elevator are dependent on such factors as
the amount of grain turned (interbin transfer), amount dryed, and amount cleaned, etc. Because the
amount of grain passing through each operation is often difficult to determine, it may be more useful
to express the emission factors in terms of the amount of grain shipped or received, assuming these
amounts are about the same over the long term. Emission factors from Table 6.4-1 have been modified
accordingly and are shown in Table 6.4-2 along with the appropriate multiplier that was used as repre-
sentative of typical ratios of throughput at each operation to the amount of grain shipped or received.
This ratio is an approximate value based on average values for turning, cleaning, and drying in each
4/77 Food and Agricultural Industry 6.4-1
-------
type of elevator. However, because operating practices in individual elevators are different, these
ratios, like the basic emission factors themselves, are more valid when applied to a group of elevators
rather than individual elevators.
Table 6.4-1. PARTICULATE EMISSION FACTORS
FOR UNCONTROLLED GRAIN ELEVATORS
EMISSION FACTOR RATING: B
Type of source
Terminal elevators
Unloaded (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drying'3
Cleaning0
Headhouse (legs)
Tripper (gallery belt)
Country elevators
Unloading (receiving)
Loading (shipping)
Removal from bins
Drying13
Cleaning0
Headhouse (legs)
Export elevators
Unloading (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drying"
Cleaning0
Headhouse (legs)
Tripper (gallery belts)
Emission factor3
Ib/ton
1.0
0.3
1.4
1.1
3.0
1.5
1.0
0.6
0.3
1.0
0.7
3.0
1.5
1.0
1.0
1.4
1.1
3.0
1.5
1.0
kg/MT
0.5
0.2
1.7
0.6
1.5
0.8
0.5
0.3
0.2
0.5
0.4
1.5
0.8
0.5
0.5
0.7
0.5
1.5
0.8
0.5
aEmission factors are in terms of pounds of dust emitted per ton of
grain processed by each operation. Most of the factors for terminal
and export elevators are based on Reference 1. Emission factors
for drying are based on References 2 and 3. The emission factors
for country elevators are based on Reference 1 and specific country
elevator test data in References 4 through 9.
Emission factors for drying are based on 1.8 Ib/ton for rack dryets
and 0.3 Ib/ton for column dryers prorated on the basis of distribu-
tion of these two types of dryers in each elevator category, as
discussed in Reference 3.
cEmission factor of 3.0 for cleaning is an average value which may
range from <0.5 for wheat up to 6.0 for corn.
The factors in Tables 6.4-1 or 6.4-2 should not be added together in an attempt to obtain a single
emission factor value for grain elevators because in most elevators some of the operations are
equipped with control devices and some are not. Therefore, any estimation of emissions must be
directed to each operation and its associated control device, rather than the elevator as a whole, unless
the purpose was to estimate total potential (i.e., uncontrolled) emissions. An example of the use of
emission factors in making an emission inventory is contained in Reference 3.
6.4-2
EMISSION FACTORS
4/77
-------
Table 6.4-2. PARTICULATE EMISSION FACTORS FOR GRAIN ELEVATORS BASED ON
AMOUNT OF GRAIN RECEIVED OR SHIPPED9
Type of source
Terminal elevators
Unloading (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drying"
Cleaning0
Headhouse (legs)
Tripper (gallery belt)
Country elevators
Unloading (receiving)
Loading (shipping)
Removal from bins
Drymgb
Cleaning0
Headhouse (legs)
Export elevators
Unloading (receiving)
Loading (shipping)
Removal from bins (tunnel belt)
Drymgb
Cleanmg0
Headhouse (legs)
Tripper (gallery belt)
Emission factor,
Ib/ton processed
1.0
0.3
1.4
1.1
3.0
1 5
1 0
0.6
0.3
1.0
0.7
30
1 5
1.0
1.0
1.4
1.1
3.0
1.5
1.0
X
Typical ratio of tons processed
to tons received or shipped"
1.0
1.0
2.0
0.1
0.2
3.0
1.7
1.0
1.0
2.1
0.3
0.1
3.1
1.0
1.0
1.2
0.01
0.2
2 2
1 1
=
Emission factor,
Ib/ton received or shipped
1.0
03
2.8
0.1
0.6
4.5
1.7
0.6
03
2 1
02
0.3
4.7
1 0
1 0
1.7
0.01
0.6
33
1 1
aAssume that over the long term the amount received is approximately equal to amount shipped.
bSeeNoteb in Table 6.4-1.
ICSee Notec in Table 6.4-1. I
"Ratios shown are average values taken from a survey of many elevators across the U.S. These ratios can be considerably different
for any individual elevator or group of elevators in the same locale.
Some of the operations listed in the table, such as the tunnel belt and belt tripper, are internal or
in-house dust sources which, if uncontrolled, might show lower than expected atmospheric emissions
because of internal settling of dust. The reduction in emissions via internal settling is not known,
although it is possible that all of this dust is eventually emitted to the atmosphere due to subsequent
external operations, internal ventilation, or other means.
Many elevators utilize control devices on at least some operations. In the past, cyclones have com-
monly been applied to legs in the headhouse and tunnel belt hooding systems. More recently, fabric
filters have been utilized at many elevators on almost all types of operations. Unfortunately, some
sources in grain elevators present control problems. Control of loadout operations is difficult because
of the problem of containment of the emissions. Probably the most difficult operation to control,
because of the large flow rate and high moisture content of the exhaust gases, is the dryers. Screen-
houses or continuously vacuumed screen systems are available for reducing dryer emissions and have
been applied at several facilities. Detailed descriptions of dust control systems for grain elevator oper-
ations are contained in Reference 2.
6.4.2.2 Grain Processing Operations - Grain processing operations include many of the operations
performed in a grain elevator in addition to milling and processing of the grain. Emission factors for
different grain milling and processing operations are presented in Table 6.4-3. Brief discussions of
these different operations and the methods used for arriving at the emission factor values shown in
Table 6.4-3 are presented below.
4/77
Food and Agricultural Industry
6.4-3
-------
Table 6.4-3. PARTICULATE EMISSION FACTORS
FOR GRAIN PROCESSING OPERATIONSl.2,3
EMISSION FACTOR RATING: 0
Type of source
Feed mills
Receiving
Shipping
Handling
Grinding
Pellet coolers
Wheat mills
Receiving
Precleaning and handling
Cleaning house
Millhouse
Durum mills
Receiving
Precleaning and handling
Cleaning house
Millhouse
Rye milling
Receiving
Precleaning and handling
Cleaning house
Millhouse
Dry corn milling
Receiving
Drying
Precleaning and handling
Cleaning house
Degerming and milling
Oat milling
Total
Rice milling
Receiving
Handling and precleaning
Drying
Cleaning and millhouse
Soybean mills
Receiving
Handling
Cleaning
Drying
Cracking and denuding
Hull grinding
Emission factora.b
(uncontrolled except where indicated)
Ib/ton
1.30
0.50
3.00
0.1 QC
0.1 QC
1.00
5.00
-
70.00
1.00
5.00
-
-
1.00
5.00
-
70.00
1.00
0.50
5.00
6.00
-
2.5Qd
0.64
5.00
1.60
5.00
-
7.20
3.30
2.00
kg/MT
0.65
0.25
1.50
0.05C
0.05C
0.50
2.50
-
35.00
0.50
2.50
-
-
0.50
2.50
-
35.00
0.50
0.25
2.50
3.00
-
1.25d
0.32
2.50
0.80
2.50
-
3.60
1.65
1.00
6.4-4
EMISSION FACTORS
4/77
-------
Table 6.4-3 (continued). PA'RTICULATE EMISSION FACTORS
FOR GRAIN PROCESSING OPERATIONS1.2.3
EMISSION FACTOR RATING: D
Type of source
Bean conditioning
Flaking
Meal dryer
Meal cooler
Bulk loading
Corn wet milling
Receiving
Handling
Cleaning
Dryers
Bulk loading
Emission factora-b
(uncontrolled except where indicated)
Ib/ton
0.10
0.57
1.50
1.80
0.27
1.00
5.00
6.00
-
-
kg/MT
0.05
0.29
0.75
0.90
0.14
0.50
2.50
3.00
-
-
aEmission factors are expressed in terms of pounds of dust emitted per ton of grain
entering the plant (i.e., received), which is not necessarily the same as the amount
of material processed by each operation.
Blanks indicate insufficient information.
cControlled emission factor (controlled with cyclones).
"Controlled emission factor.lThis represents several sources in one plant; some
controlled with cyclones and others controlled with fabric filters.)
Emission factor data for feed mill operations are sparse. This is partly due to the fact that many
ingredients, whole grain and other dusty materials (bran, dehydrated alfalfa, etc.), are received by
both truck and rail and several unloading methods are employed. However, because some feed mill
operations (handling, shipping, and receiving) are similar to operations in a grain elevator, an emis-
sion factor for each of these different operations was estimated on that basis. The remaining
operations are based on information in Reference 2.
Three emission areas for wheat mill processing operations are grain receiving and handling, clean-
ing house, and milling operations. Data from Reference 1 are used to estimate emissions factors for
grain receiving and handling. Data for the cleaning house are insufficient to estimate an emission
factor, and information contained in Reference 2 is used to estimate the emission factor for milling
operations. The large emission factor for the milling operation is somewhat misleading because almost
all of the sources involved are equipped with control devices to prevent product losses; fabric filters
are widely used for this purpose.
Operations for durum mills and rye milling are similar to those of wheat milling. Therefore, most
of these emission factors are assumed equal to those for wheat mill operations.
The grain unloading, handling, and cleaning operations for dry corn milling are similar to those in
other grain mills, but the subsequent operations are somewhat different. Also, some drying of corn
received at the mill may be necessary prior to storage. An estimate of the emission factor for drying is
obtained from Reference 2. Insufficient information is available to estimate emission factors for
degerming and milling.
Information necessary to estimate emissions from oat milling is unavailable, and no emission
factor for another grain is considered applicable because oats are reported to be dustier than many,
other grains. The only emission factor data available are for controlled emissions.2 An overall con-
trolled emission factor of 2.5 Ib/ton is calculated from these data.
4/77
Food and Agricultural Industry
6.4-5
-------
Emission factors for rice milling are based on those for similar operations in other grain handling
facilities. Insufficient information is available to estimate emission factors for drying, cleaning, and
mill house operations.
Information contained in Reference 2 is used to estimate emission factors for soybean mills.
Emissions information on corn wet-milling is unavailable in most cases due to the wide variety of
products and the diversity of operations. Receiving, handling, and cleaning operations emission
factors are assumed to be similar to those for dry corn milling.
Many of the operations performed in grain milling and processing plants are the same as those in
grain elevators, so the control methods are similar. As in the case of grain elevators, these plants often
use cyclones or fabric filters to control emissions from the grain handling operations (e.g:, unloading,
legs, cleaners, etc.). These same devices are also often used to control emissions from other processing
operations; a good example of this is the extensive use of fabric filters in flour mills. However, there are
also certain operations within some milling operations that are not amenable to use of these devices.
Therefore, wet scrubbers have found some application, particularly where the effluent gas stream has
a high moisture content. Certain other operations have been found to be especially difficult to control,
such as rotary dryers in wet corn mills. Descriptions of the emission control systems that have been
applied to operations within the grain milling and processing industries are contained in Reference 2.
This section was prepared for EPA by Midwest Research Institute.10
References for Section 6.4
1. Gorman, P.G. Potential Dust Emission from a Grain Elevator in Kansas City, Missouri. Prepared
by Midwest Research Institute for Environmental Protection Agency, Research Triangle Park,
N.C. under Contract No. 68-02-0228, Task Order No. 24. May 1974.
2. Shannon, L.J. et al. Emission Control in the Grain and Feed Industry , Volume I - Engineering
and Cost Study. Final Report. Prepared for Environmental Protection Agency by Midwest
Research Institute. Document No. EPA-450/3-73-003a. Research Triangle Park, N.C. December
1973.
3. Shannon, L.J. et al. Emission Control in the Grain and Feed Industry, Volume II - Emission
Inventory. Final Report. Prepared by Midwest Research Institute for Environmental Protection
Agency, Research Triangle Park, N.C. Report No. EPA-450/3-73-003b. September 1974
4. Maxwell, W.H. Stationary Source Testing of a Country Grain Elevator at Overbrook, Kansas.
Prepared by Midwest Research Institute for Environmental Protection Agency under EPA
Contract No. 68-02-1403. Research Triangle Park, N.C. February 1976.
5. Maxwell, W.H. Stationary Source Testing of a Country Grain Elevator at Great Bend, Kansas.
Prepared by Midwest Research Institute for Environmental Protection Agency under EPA
Contract No. 68-02-1403. Research Triangle Park, N.C. April 1976.
6. Belgea, F.J. Cyclone Emissions and Efficiency Evaluation. Report submitted to North Dakota
State Department of Health on tests at an elevator in Edenburg, North Dakota, by Pollution
Curbs, Inc. St. Paul, Minnesota. March 10, 1972.
7. Trowbridge, A.L. Particulate Emission Testing - ERG Report No. 4-7683. Report submitted to
North Dakota State Department of Health on tests at an elevator in Egeland, North Dakota, by
Environmental Research Corporation. St. Paul, Minnesota. January 16, 1976.
6.4-6 EMISSION FACTORS 4/77
-------
8. Belgea, F. J. Grain Handling Dust Collection Systems Evaluation for Farmers Elevator Company,
Minot, North Dakota. Report submitted to North Dakota State Department of Health, by
Pollution Curbs, Inc. St. Paul, Minnesota. August 28, 1972.
9. Belgea, F.J. Cyclone Emission and Efficiency Evaluation. Report submitted to North Dakota
State Department of Health on tests at an elevator in Thompson, North Dakota, by Pollution
Curbs, Inc. St. Paul, Minnesota. March 10, 1972.
10. Schrag, M.P. et al. Source Test Evaluation for Feed and Grain Industry. Prepared by Midwest
Research Institute, Kansas City, Mo., for Environmental Protection Agency, Research Triangle
Park, N.C., under Contract No. 68-02-1403, Task Order No. 28. December 1976. Publication No.
EPA-450/3-76-043.
4/77 Food and Agricultural Industry 6.4-7
-------
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6.5 FERMENTATION
6.5.1 Process Description1
For the purpose of this report only the fermentation industries associated with food will be considered. This
includes the production of beer, whiskey, and wine.
The manufacturing process for each of these is similar. The four main brewing production stages and their
respective sub-stages are: (1) brewhouse operations, which include (a) malting of the barley, (b) addition of
adjuncts (corn, grits, and rice) to barley mash, (c) conversion of starch in barley and adjuncts to maltose sugar by
enzymatic processes, (d) separation of wort from grain by straining, and (e) hopping and boiling of the wort; (2)
fermentation, which includes (a) cooling of the wort, (b) additional yeast cultures, (c) fermentation for 7 to 10
days, (d) removal of settled yeast, and (e) filtration and carbonation; (3) aging, which lasts from 1 to 2 months
under refrigeration; and (4) packaging, which includes (a) bottling-pasteurization, and (b) racking draft beer.
The major differences between beer production and whiskey production are the purification and distillation
necessary to obtain distilled liquors and the longer period of aging. The primary difference between wine making
and beer making is that grapes are used as the initial raw material in wine rather than grains.
6.5.2 Emissions1
Emissions from fermentation processes are nearly all gases and primarily consist of carbon dioxide, hydrogen,
oxygen, and water vapor, none of which present an air pollution problem. Emissions of particulates, however, can
occur in the handling of the grain for the manufacture of beer and whiskey. Gaseous hydrocarbons are also
emitted from the drying of spent grains and yeast in beer and from the whiskey-aging warehouses. No significant
emissions have been reported for the production of wine. Emission factors for the various operations associated
with beer, wine, and whiskey production are shown in Table 6.5-1.
2/72 Food and Agricultural Industry 6.5-1
-------
Table 6.5-1. EMISSION FACTORS FOR FERMENTATION PROCESSES
EMISSION FACTOR RATING: E
Type of product
Beer
Grain handling3
Drying spent grains, etc.3
Whiskey
Grain handling8
Drying spent grains, etc.3
Aging
Wine
Particulates
Ib/ton
3
5
3
5
-
Nege
kg/MT
1.5
2.5
1.5
2.5
-
Neg
Hydrocarbons
Ib/ton
—
NAb
-
NA
10°
Nege
kg/MT
—
NA
-
NA
0.024d
Neg
3Based on section on grain processing.
bNo emission factor available, but emissions do occur.
cPounds per year per barrel of whiskey stored.
"Kilograms per year per liter of whiskey stored.
eNo significant emissions.
References for Section 6.5
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA.-22-69-119. April 1970.
2. Shreve, R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company. 1967. p.
591-608.
6.5-2
EMISSION FACTORS
2/72
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6.6 FISH PROCESSING revised by Susan Sercer
6.6.1 Process Description
Fish processing includes the canning of fish and the manufacturing of by-products such as fish'oil
and fish meal. The manufacturing of fish oil and fish meal are known as reduction processes. A general-
ized fish processing operation is presented in Figure 6.6-1 .
Two types of canning operations are used. One is the "wet fish" method in which trimmed and
eviscerated fish are cooked directly in open cans. The other operation is the "pre-cooked" process in
which eviscerated fish are cooked whole and portions are hand selected and packed into cans. The pre-
cooked process is used primarily for larger fish such as tuna.
By-product manufacture of rejected whole fish and scrap requires several steps. First, the fish scrap
mixture from the canning line is charged to a live steam cooker. After the material leaves the cooker,
it is pressed to remove water and oil. The resulting press cake is broken up and dried in a rotary drier.
Two types of driers are used to dry the press cake: direct-fired and steam-tube driers. Direct-fired
driers contain a stationary firebox ahead of the rotating section. The hot products of combustion from
the firebox are mixed with air and wet meal inside the rotating section of the drier. Exhaust gases are
generally vented to a cyclone separator to recover much of the entrained fish meal product. Steam-
tube driers contain a cylindrical bank of rotating tubes through which hot, pressurized steam is
passed. Heat is indirectly transferred to the meal and the air from the hot tubes. As with direct-fired
driers, the exhaust gases are vented to a cyclone for product recovery.
6.6.2 Emissions and Controls
Although smoke and dust can be a problem, odors are the most objectionable emissions from fish
processing plants. By-product manufacture results in more of these odorous contaminants than
cannery operations because of the greater state of decomposition of the materials processed. In gener-
al, highly decayed feedstocks produce greater concentrations of odors than do fresh feedstocks.
The largest odor sources are the fish meal driers. Usually, direct-fired driers emit more odors than
steam-tube driers. Direct-fired driers will also emit smoke, particularly if the driers are operated
under high temperature conditions. Cyclones are frequently employed on drier exhaust gases for
product recovery and paniculate emission control.
Odorous gases from reduction cookers consist primarily of hydrogen sulfide [H2S] and trimethyl-
amine [(CH3).,N]. Odors from reduction cookers are emitted in volumes appreciably less than from fish
meal driers. There are virtually no particulate emissions from reduction cookers.
Some odors are also produced by the canning processes. Generally, the pre-cooked process emits
less odorous gases than the wet-fish process. This is because in the pre-cooked process, the odorous
exhaust gases are trapped in the cookers, whereas in the wet-fish process, the steam and odorous
offgases are commonly vented directly to the atmosphere.
Fish cannery and fish reduction odors can be controlled with afterburners, chlorinator-scrubbers,
and condensers. Afterburners are most effective, providing virtually 100 percent odor control; how-
ever they are costly from a fuel-use standpoint. Chlbrinator-scrubbers have been found to be 95 to 99
percent effective in controlling odors from cookers and driers. Condensers are the least effective
control device. Generally, centrifugal collectors are satisfactory for controlling excessive dust emis-
sions from driers.
Emission factors for fish processing are presented in Table 6.6-1.
4/77 Food and Agricultural Industry 6.6-1
-------
E
2
05
2
T:
5
05
c
O)
O)
CD
CD
3
LL
6.6-2
EMISSION FACTORS
4/77
-------
Table 6.6-1. EMISSION FACTORS FOR FISH PROCESSING PLANTS
EMISSION FACTOR RATING: C
Emission source
Cookers, canning
Cookers, fish scrap
Fresh fish
Stale fish
Dryers '
Particulates
Ib/ton
Neg.a
Neg.a
Neg.a
0.1 d
kg/MT
Neg.a
Neg.a
Neg.a
0.05d
Trimethylamine
(CH3)3N
Ib/ton
NAb
0.3C
3.5C
NAd
kg/MT
NAb
0.1 5C
1.75C
NAd
Hydrogen sulfide
(H2S)
Ib/ton
NAb
0.01C
0.2°
NAd
kg/MT
NAb
0.005C
0.10°
NAd
aReference 1.
^Although it is known that odors are emitted from canning cookers, quantitative estimates are not available.
"•Reference 2.
"Limited data suggest that there is not much difference in paniculate emissions between steam tube and direct-fired
dryers. Based on reference 1.
References for Section 6.6
1. Walsh, R.T., K.D. Luedtke, and L.K. Smith. Fish Canneries and Fish Reduction Plants. In: Air
Pollution Engineering Manual. Danielson, J.A. (ed.). U.S. DHEW, PHS, National Center for Air
Pollution Control. Cincinnati, Ohio. Publication Number 999-AP-40. 1967. p. 760-770.
2. Summer, W. Methods of Air Deodorization. New York, Elsevier Publishing Company. 1963. p.
284-286.
4/77
Food and Agricultural Industry
6.6-3
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6.7 MEAT SMOKEHOUSES
6.7.1 Process Description1
Smoking is a diffusion process in which food products are exposed to an atmosphere of hardwood smoke,
causing various organic compounds to be absorbed by the food. Smoke is produced commerically in the United
States by three major methods: (1) by burning dampened sawdust (20 to 40 percent moisture), (2) by burning
dry sawdust (5 to 9 percent moisture) continuously, and (3) by friction. Burning dampened sawdust and
kiln-dried sawdust are the most widely used methods. Most large, modern, production meat smokehouses are the
recirculating type, in which smoke is circulated at reasonably high temperatures throughout the smokehouse.
6.7.2 Emissions and Controls1
Emissions from smokehouses are generated from the burning hardwood rather than from the cooked product
itself. Based on approximately 110 pounds of meat smoked per pound of wood burned (110 kilograms of meat
per kilogram of wood burned), emission factors have been derived for meat smoking and are presented in Table
6.7-1.
Emissions from meat smoking are dependent on several factors, including the type of wood, the type of smoke
generator, the moisture content of the wood, the air supply, and the amount of smoke recirculated. Both
low-voltage electrostatic precipitators and direct-fired afterburners may be used to reduce particulate and organic
emissions. These controlled emission factors have also been shown in Table 6.7-1.
Table 6.7-1. EMISSION FACTORS FOR MEAT SMOKINGa-b
EMISSION FACTOR RATING: D
Pollutant
Particulates
Carbon monoxide
Hydrocarbons (CH4)
Aldehydes (HCHO)
Organic acids (acetic)
Uncontrolled
Ib/ton of meat
0.3
0.6
0.07
0.08
0.2
kg/MT of meat
0.15
0.3
0.035
0.04
0.10
Controlled0
Ib/ton of meat
0.1
Negd
Neg
0.05
0.1
kg/MT of meat
0.05
Neg
Neg
0.025
0.05
aBased on 110 pounds of meat smoked per pound of wood burned (110 kg meat/kg wood burned).
^References 2, 3, and section on charcoal production.
cControls consist of either a wet collector and low-voltage precipitator in series or a direct-fired afterburner.
dWith afterburner.
2/72
Food and Agricultural Industry
6.7-1
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References for Section 6.7
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA-22-69-119. April 1970.
2. Carter, E. Private communication between Maryland State Department of Health and Resources Research,
Incorporated. November 21, 1969.
3. Polglase, W.L., H.F. Dey, and R.T. Walsh. Smokehouses. In: Air Pollution Engineering Manual. Danielson, J.
A. (ed.). U.S. DHEW, PHS, National Center for Air Pollution Control. Cincinnati, Ohio. Publication Number
999-AP-40. 1967. p. 750-755.
6.7-2 EMISSION FACTORS 2/72
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6.8 NITRATE FERTILIZERS
6.8.1 General1'2
For this report, nitrate fertilizers are defined as the product resulting from the reaction of nitric acid and
ammonia to form ammonium nitrate solutions or granules. Essentially three steps are involved in producing
ammonium nitrate: neutralization, evaporation of the neutralized solution, and control of the particle size and
characteristics of the dry product.
Anhydrous ammonia and nitric acid (57 to 65 percent HNC^)3'4 are brought together in the neutralizer to
produce ammonium nitrate. An evaporator or concentrator is then used to increase the ammonium nitrate
concentration. The resulting solutions may be formed into granules by the use of prilling towers or by ordinary
granulators. Limestone may be added in either process in order to produce calcium ammonium nitrate.5 ^
6.8.2 Emissions and Controls
The main emissions from the manufacture of nitrate fertilizers occur in the neutralization and drying
operations. By keeping the neutralization process on the acidic side, losses of ammonia and nitric oxides are kept
at a minimum. Nitrate dust or particulate matter is produced in the granulation or prilling operation. Particulate
matter is also produced in the drying, cooling, coating, and material handling operations. Additional dust may
escape from the bagging and shipping facilities.
Typical operations do not use collection devices on the prilling tower. Wet or dry cyclones, however, are used
for various granulating, drying, or cooling operations in order to recover valuable products. Table 6.8-1 presents
emission factors for the manufacture of nitrate fertilizers.
2/72 Food and Agricultural Industry 6.8-1
-------
Table 6.8-1. EMISSION FACTORS FOR NITRATE FERTILIZER
MANUFACTURING WITHOUT CONTROLS
EMISSION FACTOR RATING: B
Type of process3
With prilling towerb
Neutralizerc-d
Prilling tower
Dryers and coolers6
With granulatorb
Neutralizerc'd
Granulator6
Dryers and coolers6'*
Particulates
Ib/ton
—
0.9
12
—
0.4
7
kg/MT
—
0.45
6
—
0.2
3.5
Nitrogen
oxides (N03)
Ib/ton
—
-
—
—
0.9
3
kg/MT
—
-
—
—
0.45
1.5
Ammonia
Ib/lon
2
—
—
2
0.5
1.3
kg/MT
1
—
_
1
0.25
0.65
aPlants will use either a prilling tower or a granulator but not both.
'•'Reference 7.
cReference 8.
"Controlled factor based on 95 percent recovery in recycle scrubber.
eUse of wet cyclones can reduce emissions by 70 percent.
Use of wet-screen scrubber following cyclone can reduce emissions by 95 to 97 percent
References for Section 6.8
1. Air Pollutant Emission Factors. Final Report. Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration, Durham, N.C., under Contract Number CPA -22-69-119. April 1970.
2. Stem, A. (ed.). Sources of Air Pollution and Their Control. In: Air Pollution Vol. Ill, 2nd Ed. New York,
Academic Press. 1968. p. 231-234.
3. Sauchelli, V. Chemistry and Technology of Fertilizers. New York, Reinhold Publishing Company. 1960.
4. Falck-Muus, R. New Process Solves Nitrate Corrosion. Chem. Eng. 74( 14): 108, July 3, 1967.
5. Ellwood, P. Nitrogen Fertilizer Plant Integrates Dutch and American Know-How. Chem. Eng. p. 136-138,
May 11, 1964.
6. Che nico, Ammonium Nitrate Process Information Sheets.
7. Unpublished source sampling data. Resources Research, Incorporated. Reston. Virginia.
8. Private communication with personnel from Gulf Design Corporation. Lakeland, Florida.
6.8-2
EMISSION FACTORS
2/72
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6.9 ORCHARD HEATERS hy Dennis H Ackcr.son
6.9.1 General1-6
Orchard heaters are commonly used in various areas of the United States to prevent frost damage to hint and
fruit trees. The five common types of orchard heaters—pipeline, lazy flame. leturn stack, cone, and solid fuel are
shown in Figure 6.9-1. The pipeline heater system is operated from a central control and fuel is distributed by a
piping system from a centrally located tank. Lazy flame, return stack, and cone heaters contain mtegial fuel
reservoirs, but can be converted to a pipeline system. Solid fuel heaters usualK consist only of solid briquettes,
which are placed on the ground and ignited.
The ambient temperature at which orchard heaters are lequned is determined primarily by the type of fruit
and stage of maturity, by the daytime temperatures, and by the moisture content of the soil and an.
During a heavy thermal inversion, both convective and radiant heating methods are useful in preventing fiost
damage; there is little difference in the effectiveness of the various heaters. The temperature response for a given
fuel rate is about the same for each type of heater as long as the heater is clean and does not leak. When theie is
little or no thermal inversion, radiant heat provided by pipeline, return stack, or cone heateis is the most effective
method for preventing damage.
Proper location of the heaters is essential to the uniformity of the radiant heat distributed among the trees.
Heaters are usually located in the center space between four trees and are staggered from one row to the next.
Extra heaters are used on the borders of the orchard.
6.9.2 Emissions1'6
Emissions from orchard heaters are dependent on the fuel usage rate and the type of heater. Pipeline heaters
have the lowest particulate emission rates of all orchard heaters. Hydrocarbon emissions are negligible in the
pipeline heaters and in lazy flame, return stack, and cone heaters that have been converted to a pipeline system.
Nearly all of the hydrocarbon losses are evaporative losses from fuel contained in the heater reservoir. Because of
the low burning temperatures used, nitrogen oxide emissions are negligible.
Emission factors for the different types of orchard heaters are presented in Table 6.9-1 and Figure 6.9-2
4/73 Food and Agricultural Industry 6.9-1
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PIPELINE HEATER
LAZY FLAME
CONE STACK
RETURN STACK
SOLID FUEL
Figure 6.9-1. Types of orchard heaters.6
6.9-2
EMISSION FACTORS
4/73
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CD
co
co
*_
0)
03
0)
CO
o
•¥ °
•S E
o
CO
CO
LLl
C3
E
Q)
0)
O
CO
0.
CM
CO
§
g>
L
'SNOISSIW3
12/75
Food and Agricultural Industry
6.9-3
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Table 6.9-1. EMISSION FACTORS FOR ORCHARD HEATERS3
EMISSION FACTOR RATING: C
Pollutant
Participate
Ib/htr-hr
kg/htr-hr
Sulfur oxides
Ib/htr-hr
kg/htr-hr
Carbon monoxide
Ib/htr-hr
kg/htr-hr
Hydrocarbonsf
Ib/htr-yr
kg/htr-yr
Nitrogen oxides'1
Ib/htr-hr
kg/htr-hr
Type of heater
Pipeline
b
b
0.1 3Sd
0.06S
6.2
2.8
Neg9
Neg
Neg
Neg
Lazy
flame
b
b
0.11S
0.05S
NA
NA
16.0
7.3
Neg
Neg
Return
stack
b
b
0.1 4S
0.06S
NA
NA
16.0
7.3
Neg
Neg
Cone
b
b
0.1 4S
0.06S
NA
NA
16.0
7.3
Neg
Neg
Solid
fuel
0.05
0,023
NAe
NA
NA
NA
Neg
Neg
Meg
Meg
References 1, 3, 4, and 6.
"Paniculate emissions for pipeline, lazy flame, return stack, and cone heators are
shown in Figure 6.9-2.
C8ased on emission factors for fuel oil combustion in Section 1.3.
dS=sulfur content.
eNot available.
fBased on emission factors for fuel oil combustion in Section 1.3. Evaporative
losses only. Hydrocarbon emissions from combustion are considered negligible.
Evaporative hydrocarbon losses for units that are part of a pipeline system are
negligible.
Negligible.
hLittle nitrogen oxide is formed because of the relatively low combustion
temperatures.
References for Section 6.9
1. Air Pollution in Ventura County. County of Ventura Health Department, Santa Paula, Calif. June 1966.
2. Frost Protection in Citrus. Agricultural Extension Service, University of California, Ventura. November
1967.
3. Personal communication with Mr. Wesley Snowden. Valentine, Fisher, and Tomlinson, Consulting Engineers,
Seattle, Washington. May 1971.
4. Communication with the Smith Energy Company, Los Angeles, Calif. Jam; - y 1968.
5. Communication with Agricultural Extension Service, University of California, Ventura, Calif. October 1969.
6. Personal communication with Mr. Ted Wakai. Air Pollution Control District, County of Ventura, Ojai, Calif.
May 1972.
6.9-4
EMISSION FACTORS
12/75
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6.10 PHOSPHATE FERTILIZERS
Nearly all phosphatic fertilizers are made from naturally occurring, phosphorus-containing minerals such as
phosphate lock. Because the phosphorus content of these mineials is not in a form that is readily available to
growing plants, the minerals must be treated to conveit the phosphorus to a plant-available form. This conversion
can be done either by the process of acidulation or by a thermal process. The intermediate steps of the mining of
phosphate rock and the manufacture of phosphoric acid are not included in this section as they are discussed in
other sections of this publication: it should be kept in mind, however, that large integrated plants may have all of
these operations taking place at one location.
In this section phosphate fertilizers have been divided into thiee categories. (1) normal superphosphate. (2)
triple superphosphate, and (3) ammonium phosphate. Emission factors for the various processes imolved aie
shown in Table 6.10-1.
Table 6.10-1. EMISSION FACTORS FOR THE PRODUCTION
OF PHOSPHATE FERTILIZERS
EMISSION FACTOR RATING: C
Type of product
Normal superphosphate0
Grinding, drying
Main stack
Triple superphosphate0
Run-of-pile (ROP)
Granular
Diammonium phosphated
Dryer, cooler
Ammoniator-granulator
Particulates3
Ib/ton
9
—
-
_
80
2
kg/MT
4.5
—
-
—
40
1
Fluoridesb
Ib/ton
-
0.15
0.03
0.10
e
0.04
kg/MT
-
0.075
0.015
0.05
e
0.02
aControl efficiencies of 99 percent can be obtained with fabric filters.
bTotal fluorides, including paniculate fluorides. Factors all represent
outlet emissions following control devices, and should be used as typical
only in the absence of specific plant information.
cReferences 1 through 3.
^References 1, 4, and 5 through 8.
Included in ammomator-granulator total.
6. 1 0. 1 Normal Superphosphate
6.10.1.1 General4'9 -Normal superphosphate (also called single or ordinary superphosphate) is the product
resulting from the acidulation of phosphate rock with sulfuric acid. Normal superphosphate contains from 16 to
22 percent phosphoric anhydride (P2^5)- The physical steps involved in making superphosphate are: (1) mixing
rock and acid, (2) allowing the mix to assume a solid form (denning), and (3) storing (curing) the material to
allow the acidulation reaction to be completed. After the curing period, the product can be ground and bagged
for sale, the cured superphosphate can be sold directly as run-of-pile product, or the material can be granulated
for sale as granulated superphosphate.
2/72
Food and Agricultural Industry
6.10-1
-------
6.10.1.2 Emissions — The gases released from the acidulation of phosphate rock contain silicon tetrafluoride,
carbon dioxide, steam, particulates, and sulfur oxides. The sulfur oxide emissions arise from the reaction of
phosphate rock and sulfuric acid.10
If a granulated superphosphate is produced, the vent gases from the granulator-ammoniator may contain
particulates, ammonia, silicon tetrafluoride, hydrofluoric acid, ammonium chloride, and fertilizer dust. Emissions
from the final drying of the granulated product will include gaseous and particulate fluorides, ammonia, and
fertilizer dust.
6. 1 0. 2 Triple Superphosphate
6.10.2.1 General4 -9-Triple superphosphate (also called double or concentrated superphosphate) is the product
resulting from the reaction between phosphate rock and phosphoric acid. The product generally contains 44 to
52 percent ?205, which is about three times the P2®5 usually found in normal superphosphates.
Presently, there are three principal methods of manufacturing triple superphosphate. One of these uses a cone
mixer to produce a pulverized product that is particularly suited to the manufacture of ammoniated fertilizers.
This product can be sold as run-of-pile (ROP), or it can be granulated. The second method produces in a
multi-step process a granulated product that is well suited for direct application as a phosphate fertilizer. The
third method combines the features of quick drying and granulation in a single step.
6.10.2.2 Emissions-Most triple superphosphate is the nongranular type. The exit gases from a plant producing
the nongranular product will contain considerable quantities of silicon tetrafluoride, some hydrogen fluoride, and
a small amount of particulates. Plants of this type also emit fluorides from the curing buildings.
In the cases where ROP triple superphosphate is granulated, one of the greatest problems is the emission of
dust and fumes from the dryer and cooler. Emissions from ROP granulation plants include silicon tetrafluoride,
hydrogen fluoride, ammonia, particulate matter, and ammonium chloride.
In direct granulation plants, wet scrubbers are usually used to remove the silicon tetrafluoride and hydrogen
fluoride generated from the initial contact between the phosphoric acid and the dried rock. Screening stations
and bagging stations are a source of fertilizer dust emissions in this type of process.
6.10.3 AMMONIUM PHOSPHATE
6.10.3.1 General— The two general classes of ammonium phosphates are monammonium phosphate and
diammonium phosphate. The production of these types of phosphate fertilizers is starting to displace the
production of other phosphate fertilizers because the ammonium phosphates have a higher plant food content
and a lower shipping cost per unit weight
There are various processes and process variations in use for manufacturing ammonium phosphates. In general,
phosphoric acid, sulfuric acid, and anhydrous ammonia are allowed to react to produce the desired grade of
ammonium phosphate. Potash salts are added, if desired, and the product is granulated, dried, cooled, screened,
and stored.
6.10-2 EMISSION FACTORS 2/72
-------
6.10.3.2 Emissions-The major pollutants from ammonium phosphate production are fluoride, particulates, and
ammonia. The largest sources of particulate emissions are the cage mills, where oversized products from the
screens are ground before being recycled to the ammoniator. Vent gases from the ammoniator tanks are the major
source of ammonia. This gas is usually scrubbed with acid, however, to recover the residual ammonia.
References for Section 6.10
1. Unpublished data on phosphate fertilizer plants. U.S. DHEW, PHS, National Air Pollution Control
Administration, Division of Abatement. Durham, N.C. July 1970.
2. Jacob, K. 0., H. L. Marshall, D. S. Reynolds, and T. H. Tremearne. Composition and Piopertics of
, Superphosphate. Ind. Eng. Chem. 54(6).722-728. June 1942.
3. Slack, A. V. Phosphoric Acid, Vol. 1, Part II. New York, Marcel Dekker, Incorporated, i 968. p. 732.
f' 4. Steam, A. (ed.). Air Pollution, Sources of Air Pollution and Their Control, Vol. Ill, 2nd Ed. New York,
Academic Press. 1968. p. 231-234.
5. Teller, A. J. Control of Gaseous Fluoride Emissions. Chem. Eng. Progr. 63(3): 75-79, March 1967.
6. Slack, A. V. Phosphoric Acid, Vol. I, Part II. New York, Marcel Dekker, Incorporated. 1968. p. 722.
7. Slack, A. V. Phosphoric Acid, Vol. 1, Part II. New York, Marcel Deklcer, Incorporated. 1968. p. 760-762.
8. Salee, G. Unpublished data from industrial source. Midwest Research Institute. June 1970.
9. Bixby, D. W. Phosphatic Fertih/er's Properties and Processes. The Sulphur Institute. Washington, D.C.
October 1966.
10. Sherwm, K. A. Transcript of Institute of Chemical Engineers, London. 32 172. 1954.
2/72 Food and Agricultural Industry 6.10-3
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6.11 STARCH MANUFACTURING
6.11.1 Process Description1
The basic raw material in the manufacture of starch is dent corn, which contains starch. The starch in the
corn is separated from the other components by "wet milling."
The shelled grain is prepared for milling in cleaners that remove both the light chaff and any heavier foreign
material. The cleaned corn is then softened by soaking (steeping) it in warm water acidified with sulfur dioxide.
The softened corn goes through attrition mills that tear the kernels apart, freeing the germ and loosening the hull.
The remaining mixture of starch, gluten, and hulls is finely giound. and the coarser fiber particles are removed by
' screening. The mixture of starch and gluten is then separated by centrifuges, after which the starch is filtered and
washed. At this point it is dried and packaged for market.
«
' 6.11.2 Emissions
ft
1 The manufacture of starch from corn can result in significant dust emissions. The various cleaning, grinding.
and screening operations are the major sources of dust emissions. Table 6.11-1 presents emission factors for starch
manufacturing.
Table 6.11-1. EMISSION FACTORS
FOR STARCH MANUFACTURING3
EMISSION FACTOR RATING: D
Type of operation
Uncontrolled
Controlled13
Particulates
Ib/ton
8
0.02
kg/MT
4
0.01
aReference 2.
°Based on centrifugal gas scrubber.
References for Section 6.11
1. Starch Manufacturing. In: Kirk-Othmer Encyclopedia of Chemical Technology, Vol. IX. New York, John
Wiley and Sons, Inc. 1964.
2. Storch, H. L. Product Losses Cut with a Centrifugal Gas Scrubber. Chem. Eng. Progr. 62:51-54. April 1966.
2/72 Food and Agricultural Industry 6.11-1
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I
6 12 SUGAR CANE PROCESSING revised by Tom Lahre
>
6.12.1 General l'3
Sugar cane is burned in the field prior to harvesting to remove unwanted foliage as well as to control rodents
and insects. Harvesting is done by hand or, where possible, by mechanical means.
After harvesting, the cane goes through a series of processing steps for conversion to the final sugar product. It
is first washed to remove dirt and trash; then crushed and shredded to reduce the size of the stalks. The juice is
next extracted by one of two methods, milling or diffusion. In milling, the cane is pressed between heavy rollers
to squeeze out the juice; in diffusion, the sugar is leached out by water and thin juices. The raw sugar then goes
through a series of operations including clarification, evaporation, and crystallization in order to produce the final
product. The fibrous residue remaining after sugar extraction is called bagasse.
All mills fire some or all of their bagasse in boilers to provide power necessary in their milling operation. Some,
having more bagasse than can be utilized internally, sell the remainder for use in the manufacture of various
chemicals such as furfural.
6.12.2 Emissions 2>3
The largest sources of emissions from sugar cane processing are the openfield burning in the harvesting of the
crop and the burning of bagasse as fuel. In the various processes of crushing, evaporation, and crystallization,
relatively small quantities of particulates are emitted. Emission factors for sugar cane field burning are shown in
Table 2.4-2. Emission factors for bagasse firing in boilers will be included in Chapter 1 in a future supplement.
References for Section 6.12
1. Sugar Cane. In: Kirk-Othmer Encyclopedia of Chemical Technology, Vol. IX. New York, John Wiley and
Sons, Inc. 1964.
2. Barley, E. F. Air Pollution Emissions from Burning Sugar Cane and Pineapple from Hawaii. In: Air Pollution
from Forest and Agricultural Burning. Statewide Air Pollution Research Center, University of California,
Riverside, Calif. Prepared for Environmental Protection Agency, Research Triangle Park, N.C. under Grant
No. R80071 I.August 1974.
3. Background Information for Establishment of National Standards of Performance for New Sources. Raw Cane
Sugar Industry. Environmental Engineering, Inc. Gainesville, Fla. Prepared for Environmental Protection
Agency, Research Triangle Park, N.C. under Contract No. CPA 70-142, Task Order 9c. July 15, 1971.
4/76 Food and Agricultural Industry 6.12-1
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References for Section 6.12
1. Sugar Cane. In: Kirk-Othmer Encyclopedia of Chemical Technology, Vol. IX. New York, John Wiley and
Sons, Inc. 1964.
2. Cooper, J. Unpublished data on emissions from the sugar cane industry. Air Pollution Control Agency, Palm
Beach County, Florida. July 1969.
I
6.12-2 EMISSION FACTORS 2/72
* U.S. GOVERNMENT PRINTING OFFICE: 1977—740-104/409 Region No. 4
-------