United States
Environmental Protection
Agency
Air and Energy Environmental
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-85/041 Jan. 1986
Project Summary
Hydrogen Chloride and
Hydrogen Fluoride Emission
Factors for the NAPAP Emission
Inventory
David C. Misenheimer, Rebecca E. Battye, Michael R. Glowers, and Arthur S.
Werner
While sulfuric and nitric acids are
considered primary precursors of acid
deposition, contributions of hydrogen
chloride (HCI) and hydrogen fluoride
(HF) are also significant. This report
summarizes the findings of a study to
identify and characterize sources of
emissions to the atmosphere of HCI and
HF. Emission factors were identified for
each major source category based on
the most recent data available and were
used to develop nationwide emissions
estimates for base year 1980. Descrip-
tions of each source category, controls
commonly used for each source, and an
assessment of the accuracy of emission
factors are also included. Major sources
of HCI are coal combustion, waste
incineration, and organic chemical man-
ufacture. Sources of HF include coal
combustion and the production of pri-
mary aluminum, HF, and phosphate
fertilizers.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
The focus of emission inventory activ-
ities within the National Acid Precipitation
Assessment Program (NAPAP) is to esti-
mate emissions of pollutants of concern
to the acid deposition phenomenon. While
sulfuric and nitric acids are considered
primary precursors of acid deposition,
contributions of hydrogen chloride (HCI)
and hydrogen fluoride (HF) are also
significant. This report presents emission
factors for HCI and HF from significant
sources of these pollutants.
Discussion and Procedure
A literature search was conducted to
identify significant anthropogenic emis-
sions sources and estimate emission
rates for each source. The emission
factors summarized in Table 1 were
developed from the most recent data
available. When available, emission fac-
tors based on tests performed by a sound
methodology and accompanied by ade-
quate background data were chosen.
Emission factors were evaluated on a
scale of A through E: A represents data
from a large data base covering a good
cross section of the industry, determined
from valid test methods, and with a high
confidence level; E represents data from a
small data base, not necessarily repre-
sentative of the industry, and with a low
confidence level; and B through D repre-
sent data with intermediate confidence
levels. National emissions estimates for
base year 1980 were calculated by multi-
plying the level of activity (production/use
rates) for each source category in 1980
(or as close to base year 1980 as possible)
by the emission factor for that source.
National emissions estimates provide a
measure of the relative importance of
each source category.
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HCI is emitted from coal combustion,
waste incineration, and organic chemical
manufacture. Approximately 660,000
tons of HCI was emitted in 1 980; over 89
percent of the total resulted from coal
combustion. HF was emitted from various
sources at the rate of 90,000 tons/year.
Coal combustion, comprising 78 percent
of the total, and primary aluminum pro-
duction, comprising almost 15 percent.
are the major HF sources. Other sources
include the fertilizer and HF manufac-
turing industries.
The rates at which HCI and HF are
emitted during coal combustion are func-
tions of coal composition and air pollution
control techniques. A study of coal com-
bustion in utility boilers conducted by the
Bureau of Mines found that most of the
chlorine in coal volatilizes and forms HCI.
There is a need for additional scientific
data which directly assess the chemical
form of fluorine emitted duiing coal
combustion. In lieu of such data and
because of the chemical similarity be-
tween fluorine and chlorine, it is assumed
that all fluorine in the feed coal reacts to
form HF.
Data compiled in 1 979 on trace element
compositions in coal were obtained from
studies by TRW and GCA and were used
to calculate emission factors for coal
combustion in utility and industrial boil-
ers. Factors calculated for bituminous
coal burned in utility boilers are 78.8 Ib
HCI/109 Btu and 9.4 Ib HF/109 Btu.
These factors were assigned an A ranking
due to the number of tests conducted,
availability of information concerning
accuracy, and types of test methods used.
Recent data (1985) developed by the
Department of Energy's Pittsburgh En-
ergy Technology Center from laboratory
tests on bituminous coal in utility boilers
resulted in emission rates of 690 Ib
chlorine/109 Btu/percent chlorine and
870 Ib fluorine/1 09 Btu/percent fluorine.
Dividing by the chlorine and fluorine
contents of the coal and assuming that
emissions are in the form of HCI and HF
result in emission factors of 28 Ib HCI/109
Btu and 4.7 Ib HF/1 09 Btu. These factors
compare favorably with those developed
from the TRW/GCA studies.
Scrubbers, electrostatic precipitators
(ESPs), cyclones, and baghouses are used
Table 1 . Emissions of Hydrogen Chloride and Hydrogen Fluoride
Emissions
Source Emission Factor* tons/yr
Coal Combustion
Utility Boilers
Bituminous
Anthracite
Lignite
Industrial Boilers
Bituminous
Anthracite
Lignite
Residential Boilers
Bituminous
Anthracite
Lignite
Propylene Oxide Manufacture
Incineration
Municipal Waste
Industrial Waste
Liquid Waste
By-product HCI Production
(without final scrubber)
(with final scrubber)
Emission
Factor
Accuracy
Rating
-HCI-
78.8
35.5
1.0
78.8
35.5
1.0
60.5
120
35. 1
7.46
5.0
5.35
1.19
3.0
0.2
lb/10aBtu
lb/10aBtu
lb/10aBtu
lb/10aBtu
lb/10aBtu
lb/W9Btu
Ib/JO9 Btu
lb/10aBtu
lb/WaBtu
Ib/ton
Ib/ton"
Ib/ton"
Ib/ton"
Ib/ton
Ib/ton
458,200
310
270
121.000
530
40
1,300
1,300
__
2,740
75,000
.-
--
--
--
A
A
A
A
A
A
c
C
C
B
E
E
E
C
C
-HF-
Coal Combustion
Utility Boilers
Bituminous
Anthracite
Lignite
Industrial Boilers
Bituminous
Anthracite
Lignite
Residential Boilers
Bituminous
Anthracite
Lignite
HF Manufacture
Tail Gas Vent
Uncontrolled
Controlled —
Caustic Scrubber
Primary Aluminum Production
Anode Baking Furnace
Prebaked Reduction Cell
Prebaked Fugitive Emissions
Vertical Soderberg Stud Cells
VSS — Fugitive Emissions
Horizontal Soderberg
Stud Cells
HSS— Fugitive Emissions
9.4
7.2
1.2
9.4
7.2
1.2
6.87
4.95
6.34
25.0
O.2
0.52
4.9
1.2
0.6
4.9
1.9
2.2
lb/10* Btu
lb/W9Btu
to/709 Btu
lb/10aBtu
lb/10aBtu
lb/10*Btu
lb/W9Btu
lb/10a Btu
lb/10a Btu
Ib/ton
Ib/ton
Ib/ton
Ib/ton
Ib/ton
Ib/ton
Ib/ton
Ib/ton
Ib/ton
54,670
60
310
14,400
110
50
150
50
21.3
9,300
1.800
2.200
--
A
A
A
A
A
A
C
C
C
E
E
A
A
A
A
A
A
A
frequently on coal-fired utility boilers as
flue gas control techniques. The primary
purpose of these controls is to remove
paniculate matter from the flue gas
stream. The efficiency of wet scrubbing
devices has been reported at about 80
percent for HCI and HF emissions from
Phosphate Fertilizer Industry
Phosphoric Acid Production
Reactor
Condenser
Controlled Emissions
Gypsum Ponds
0.37 lb/tonc
0.043 lb/tonc
0.010 lb/tonc
0.42 Ib/ton"
150
6.400
C
C
C
D
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able 1. (Continued)
, Emission
Factor
Emissions Accuracy
Source Emission Factor* tons/yr Rating
Triple Superphosphate
Manufacture
Reactor/Dryer (granulor) 21.0 Ib/tori* A
Controlled Igranulor) 0.24 lb/tona 0.21 A
Diammonium Phosphate
Manufacture
Dryers and Coolers 0.3 Ib/ton* - A
Ammoniator/Granulator 0.3 Ib/ton" •- A
Controlled Emissions 0.08 Ib/ton* 245 A
mission factors are based on the rate of production for the specific source category unless
therwise noted; for readers more familiar with the metric system: 1 Btu = 1.055 kJ, 1 lb = 0.454
g, and 1 ton = 907.2 kg.
he emission factor units are Ib HCI/ton material burned.
he emission factor units are Ib HF/ton phosphate rock processed.
he emission factor units are Ib HF/ton P20i.
lituminous-coal-fired utility boilers. Bag-
louses which have sorbent or alkaline
materials introduced may remove a sub-
tantial amount of HCI and HF. A study of
he use of nacholite and sodium bicar-
lonate as dry sorbent resulted in a 95 to
^ percent HCI removal. However, under
rmal operating practices, baghouses,
:SPs, and cyclones have no significant
sffect on removal of HCI or HF.
Another control technique, flue gas
Jesulfurization (FGD), is used to remove
ulfur oxides from coal combustion. Data
lave indicated that FGD is at least 95
>ercent effective in removal of HCI. No
jata are available to quantify removal
ifficiencies of HF.
Several emission factors received low
ratings because of limited data. Factors
or HCI from residential boilers, HCI
manufacturing, and waste incineration
received intermediate to poor rankings
because of the few plants actually tested
and the absence of information on test
methodology. Factors for HF emissions
from residential boilers, phosphoric acid
production, and HF manufacture were
assigned intermediate to low rankings
based on the few studies, absence of
information concerning accuracy of test
methods, and the number of assumptions
made in determining these factors. Ad-
ditional data which address emission
rates of HCI and HF from these sources
would be beneficial.
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D. Misenheimer, P. Battye, M. Clowers. and A. Werner are with GC'A/Technology
Division, Chapel Hill, NC 27514.
J. David Mobley is the EPA Project Officer (see below).
The complete report, entitled "Hydrogen Chloride and Hydrogen Fluoride Emission
Factors for the NAPAP Emission Inventory," (Order No. PB 86-134 020/AS;
Cost: $11.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
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