EPA-450/4-84-007i
September 1985
Locating And Estimating Air Emissions
From Sources Of Phosgene
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office Of Air And Radiation
Office Of Air Quality Planning And Standards '
Research Triangle Park, North Carolina 27711 ;
r
September 1985
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This report has been reviewed by the Office Of Air Quality Planning And Standards, U.S.. Environmental Protection
Agency, and has been approved for publication as received from the contractor. Approval does not signify that the
contents necessarily reflect the views and policies of the Agency, neither does mention of trade names or commercial
products constitute endorsement or recommendation for use.
EPA-450/4-84-007!
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CONTENTS
Figures iv
Tables v
1. Purpose of Document 1
2. Overview of Document Contents 3
3. Background . ; 5
• Properties of phosgene 5
Overview of phosgene production and use 7
Miscellaneous phosgene sources . 7
References For Section 3 11
4. Phosgene Emission Sources > 12
I
Phosgene production . 12
Isocyanate production 20
Polycarbonate production 25
Herbicides.and pesticides production 29
. References For Section 4 35
:i
5. Source Test Procedures . 37
References for Section 5 39
Appendix i
Phosgene Emissions Data " — — i A-l
References For Appendix i A-14
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FIGURES ;
Number i Page
1 Chemical Use Tree for Phosgene 9
2 Basic Operations in a Phosgene Production Process 14
3a Flow Diagram of a Phosgene Emission Control System for
Merchant Phosgene Operations 16
3b Flow Diagram of a Phosgene Emission Control System for
Phosgene Production and Onsite Consumption 17
4 Basic Operations Used in the Production of Diiamino Toluenes 21
5 Basic Operations Used in the Production of Toluene
Diisocyanate ; 22
6 Flow Diagram of a Phosgene Emission Control System 24
7 Basic Operations Used in the Production of Polycarbonates 27
8 Control System for Polycarbonate Production 28
9 Basic Operations Used in the Production of Phenyl Ureas 31
10 Emission Control System for Phenyl Urea Production 32
11 Sampling Train for the Measurement of Phosgene 38
IV
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TABLES
Number ,
1 Some Physical Properties of Phosgene 6
2 Companies That Produce Phosgene . 8
3 Estimated Phosgene Emissions From a Hypothetical Phosgene
Plant 20
4 Estimated Phosgene Emissions From a Hypothetical Toluene
Diisocyanate Plant Using Phosgene Produced on Site 25
5 Estimated Phosgene Emissions From a Hypothetical Polycar-
bonate Plant Using Phosgene Produced on Site 29
6 Estimated Phosgene Emissions From a Hypothetical Herbicide
and Pesticide Plant Using Phosgene Produced on Site 34
A-l . Summary of Estimated Phosgene Emissions from Hypothetical
Phosgene and Phosgene Derivative Production Facilities A-3
A-2 Estimated Fugitive Phosgene Emissions From a Hypothetical
Phosgene Plant Producing 200 Million Pounds of Phosgene
Per Year A_8
A-3 Estimated Fugitive Phosgene Emissions From a Hypothetical
Toluene Diisocyanate Production Facility A-9
A-4 Estimated Fugitive Phosgene Emissions From a Hypothetical
Polycarbonate Production Facility A-10
A-5 Estimated Fugitive Phosgene Emissions From a Hypothetical
Herbicide and Pesticide Production Facility A-ll
A-6 Process Fugitive Emission Factors for Plants A-12
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SECTION 1
PURPOSE OF DOCUMENT '.
The U.S. Environmental Protection Agency (EPA), States, and local air
pollution control agencies are becoming increasingly aware of the presence of
substances in the ambient air that may be toxic at certain concentrations.
This awareness, in turn, has led to attempts to identify source/receptor
relationships for these substances and to develop control programs to regu-
late emissions. Unfortunately, very little information is available on the
ambient air concentrations of these substances or on the sources that may be
discharging them to the atmosphere.
To assist groups interested in inventorying air emissions of various po-
tentially toxic substances, EPA is preparing a series of documents that com-
piles available information on-the sources and emissions of these substances.
This document specifically deals with phosgene. Its intended audience in-
eludes Federal, State, and local air pollution personnel and others who are
interested in locating potential emitters of phosgene and making gross esti-
mates of air emissions therefrom.
Because of the limited amounts of data available on phosgene emissions,
and because the configuration of many sources will not be the same as those
described herein, this document is best used as a primer to inform air pol-
lution personnel about 1) the types of sources that may emit phosgene,
2) process variations and release points that may be expected within these
sources, and 3) available emissions information indicating the potential for
phosgene to be released into the air from each operation.
The reader is strongly cautioned against using the emissions information
contained in this document in any attempt to develop an'exact assessment of
emissions from any particular facility. Because of insufficient data, no
estimate can be made of the error that could result when these factors are
used to calculate emissions from any given facility. It Is possible, in some
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extreme cases, that orders-of-magnitude differences could result between
actual and calculated emissions, depending on differences in source config-
urations, control equipment, and operating practices. Thus, in situations
where an accurate assessment of phosgene emissions is necessary, source-
specific information should be obtained to confirm the existence of particu-
lar emitting operations, the types and effectiveness of control measures, and
the impact of operating practices. A source test and/or material balance
should be considered as the best means to determine air emissions directly
from an operation.
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SECTION 2
OVERVIEW OF DOCUMENT CONTENTS
' |
As noted in Section 1, the purpose of this document 1s to assist Federal,
State, and local air pollution agencies and others who are interested in loca-
ting potential air emitters of phosgene and making gross estimates of air
emissions therefrom. Because of the limited background data available, the
information summarized in this document does not and should not be assumed to
represent the source configuration or emissions associated with any particular
facility.
This section provides an overview of the contents of this document. It
briefly outlines the nature, extent, and format of the material presented in
the remaining sections of this report.
Section 3 of this document provides.a summary of the physical.and chemi-
cal characteristics of phosgene and an overview of its production and uses. A
chemical use tree summarizes the quantities of phosgene consumed in various
end use categories in the United States. This background section presents a
general perspective on the nature of the substance and where it is manufac-
tured and consumed.
Section 4 of this document focuses on major industrial source categories
that may discharge phosgene air emissions. The production of phosgene is
discussed, along with the use of phosgene as an intermediate in the produc-
tion of isocyanates, polycarbonates, carbamates, chloroformates, and other
esters of carbonic acid. Example process descriptions and flow diagrams are
provided and potential emission points are identified for each of the major
industrial source categories discussed. Where the limited data allow, emis-
sion estimates are presented that show the potential for phosgene emissions
before and after industry-applied controls. Individual companies reported to
be involved with either the production or use of phosgene are named.
Section 5 summarizes available procedures for source sampling and analy-
sis of phosgene. Details are not presented, and the EPA neither gives nor
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implies any endorsement of these sampling and analysis procedures. Because
the EPA has not yet made a general evaluation of these methods, this document
merely provides an overview of applicable source sampling procedures and ref-
erences for the use of those interested in conducting source tests.
Companies that produce or use phosgene, state air control agencies, and
other authorities were contacted in an effort to locate data representing
measured phosgene emissions. Only one known direct measurement has been made
of phosgene emissions from industries that produce or use phosgene. Aside
from this single measurement, the only emission data found were company
engineering estimates. These estimated emission levels are included in this
report even though the companies provided no bases for them.
Other information was used to obtain phosgene emission estimates. For
example, health effects and air monitoring programs are discussed, but only
to the extent that they were used to estimate phosgene emissions. References
are cited and the methodology is discussed in sufficient detail to allow the
reader to assess the probable limitations of these estimates. Additional
background information is. included in the appendix to assist the reader in
understanding the basis for all -of the estimates presented in the report."
• Comments on the contents or usefulness of this document are welcomed, as
is any information on process descriptions, operating practices, control mea-
sures, and emission information that would enable EPA to improve its contents
All comments should be sent to:
Chief, Source Analysis Section (MD-14)
Air Management Technology Branch
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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SECTION 3
BACKGROUND
3.1 PROPERTIES OF PHOSGENE
Phosgene is a highly toxic, colorless gas that condenses at 0°C to a
fuming liquid. Impurities can discolor liquid phosgene ;and cause -it to turn
a pale yellow to green color. The human nose can detect its characteristic
odor only briefly at the time of initial exposure. At ei concentration of
about 0.5 ppm in the air, this odor has been described as similar to that of
new-mown hay or cut green corn. At higher concentrations, the odor may be
strong, stifling, and unpleasant. A common decomposition product of chlo-
rinated compounds, phosgene is noncombustible. Its molecular formula is
COC12, and it has the following planar structure. i
Cl Cl
I
The physical properties of phosgene (also known as carbcmyl chloride, carbon
oxychloride, carbonic acid dichloride, chloroformyl chloride, and combat
O
gas ) are presented in Table 1.
Phosgene is soluble in aromatic and aliphatic hydrocarbons, chlorinated
hydrocarbons, carbon tetrachloride, organic acids, and esters, and it is only
slightly soluble in water. It is removed easily from solvents by heating or
air blowing. Because the density of phosgene is more than three times that
of air, concentrated emission plumes tend to settle to the ground and collect
in low areas. ,
Phosgene decomposes to hydrogen chloride and carbon dioxide if contami-
nated with water. Hence, wet phosgene is very corrosive and poses an addi-
tional hazard from pressure buildup in closed containers.
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TABLE 1. SOME PHYSICAL PROPERTIES OF PHOSGENE
1
Properties and characteristics
Value
Molecular weight
Melting point, °C
Boiling point (at 101.3 kPa = 1 a tin), °C
Density at 20°C, g/cra3
Vapor pressure at 20°C, kPa
Vapor density (air - 1.0)
Critical temperature, °C
Density at critical point, g/cm3
Critical pressure, MPa
Latent heat of vaporization (at 7.5°C),
Molar heat capacity of liquid (at 7.5°C), J/IC
Molar heat of formation, kJ
from elements
from CO and Cl,
98.92
•127.84
7,
1.
48
387
161.68
3.4
182.0
0.52
5.68
243
100.8
218
108
aTo convert kPa to psi,.multiply by 0.145.
bTo convert MPa to psi, multiply by 145.
cTo convert J to cal, divide by 4.184.
•Phosgene reacts with many inorganic and organic reagents. The reaction
of oxides and sulfides of metals with phosgene at elevated temperatures
yields very pure chlorides. Phosphates and silicates of metals react with
phosgene at'elevated temperatures and yield.metal chloride, phosphorus oxy-
chloride, or silicon dioxide. Anhydrous aluminum chloride forms a variety of
complexes with phosgene: Al2Clg-5COCl2 at low temperatures, Al2Clg-3COCl2 at
30°C, and AUClg-COClg at above 55°C. Ammonia reacts vigorously with phos-
gene in solution; the products are urea, biuret, ammelide (a polymer of
urea), cyanuric acid, and, sometimes, cyamelide (a polymer of cyanic acid).
Phosgene also reacts with a multitude of nitrogen, oxygen, sulfur, and
carbon compounds.1 Reaction with primary alky! and aryl amines yields carba-
moyl chlorides, which can be dehydrohalogenated readily to isocyanate (an in-
termediate in the manufacture of polyurethane resins). Secondary amines also
form carbamyl chlorides when reacted with phosgene. The reaction of phosgene
with amino acids has been used to isolate and purify chloroformate deriva-
tives. Hydrazine reacts with phosgene to yield carbohydrazine. The
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reaction of phosgene with alcohols, which yields esters, is commercially
important because it serves as a basis of widely used polymer systems (poly-
carbonates).
3.2 OVERVIEW OF PHOSGENE PRODUCTION AND USE {
'i
Phosgene is used as a chemical intermediate (i.e.,;feedstock) in the
production of various commercial products. Most commercially produced phos-
gene is used captive!y at the production sites in the manufacture of other
chemicals. Less than 2 percent of the phosgene produced reaches the market-
place. Phosgene is currently produced in the United States by 14 companies
at 17 manufacturing facilities (see Table 2). As of January 1983 the annual
estimated production capacity was about one million tons.4
The chemical use tree in Figure 1 shows the current uses of phosgene.
The manufacture of isocyanates consumes about 85 percent of the world's
35
phosgene production. » The primary use of phosgene is in the production of
O
toluene diisocyanate (TDI), a precursor of the polyurethane resins used to
make foams, elastomers, and coatings. A rapidly growing use of phosgene is
in the manufacture of po'lymethylene polyphenylisocyanate (PMPPI), which is
used in. the production of rigid polyurethane foams. The polycarbonate
resins used in appliance and electrical tool housings, electronic parts, and
break-resistant glazing are also phosgene-based. About 6 percent of the
phosgene production is consumed in the polycarbonate industry.5 The remain-
ing 7 to 9 percent is used in the manufacture of herbicides, pesticides,
dyes, Pharmaceuticals, and other specialty chemicals. The latter include
acyl chlorides, chloroformate esters (intermediates in the production of
ore-flotation agents and perfumes), diethyl carbonate, and dimethyl carbamyl
chloride. !
3.3 MISCELLANEOUS PHOSGENE SOURCES
3.3.1 Atmospheric Photoxidation of Chlorinated Hydrocarbons
Under laboratory conditions, phosgene has been shown to form when chlo-
roform, methylene chloride, perch!oroethylene, and trichloroethylene are
irradiated with ultraviolet light. Ambient phosgene measured in urban and
nonurban air samples in California appears to confirm the possibility of
photochemical phosgene formation in the troposphere. 7
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TABLE 2. COMPANIES THAT PRODUCE PHOSGENE"
Company
Location
End Product
BASF Wyandotte Corp.
Dow Chemical Co.
E. I. duPont de Nemours & Co.,
Inc.
Essex Chemical Co.
General Electric Co.
ICI Americas
Laurel Industries
Mobay Chemical Co.
01 in Corp.
PPG Industries .
Stauffer Chemical Co.
. * «
Upjohn Co.
Union Carbide Corp.
Van De Mark Chemical Co., Inc.
Geismar, La.
Freeport, Tex.
Deepwater Point, N.J.
Baltimore, Md.
Mount Vernon, Ind.
Geismar, La.
La Porte, Tex.
Cedar Bayou, Tex.
New Martinsville, W. Va,
Lake Charles, La.
Moundsville, W. Va.
Barberton, Ohio
Cold Creek, Ala.
St. Gabriel, La.
La Porte, Tex.
Institute, W. Va
Lockport, N.Yo
Isocyanates
Isocyanates
Isocyanates,
carbamates
Pesticides
Polycarbonate
Isocyanates
Merchant phosgene,
chloroformates
Isocyanates
Isocyanates
Isocyanates
Isocyanates
Pesticides
Pesticides
Pesticides
Isocyanates
Isocyanates
Merchant phosgene
Note: This listing is subject to change as market conditions change, facility
ownership changes, plants are closed down, etc. The reader should
verify the existence of particular facilities by consulting current
listings and/or the plants themselves. The level of phosgene emissions
from any given facility is a function of variables such as capacity,
throughput, and control measures. It should be determined through
direct contacts with plant personnel.
It is difficult, however, to assess the amount of phosgene formed in the
atmosphere. Although phosgene is evidently one of the photolysis products of
a number of high-volume chlorinated hydrocarbon solvents, the role and sig-
nificance of.each solvent, the half-life of phosgene in the air, and the
atmospheric fate of phosgene are not well understood. The quantities of
phosgene produced by photolysis, however, may be much higher than those
emitted by the chemical industry.
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3.3.2 Thermal and Ultraviolet Decomposition of Chlorinated Hydrocarbons
Phosgene can be produced from the heating and resulting decomposition of
many chlorinated hydrocarbons, including methylene chloride, monochloro-
benzene, and dichlorobenzene (used as solvents in polymerization reactions
involving phosgene),.carbon tetrachloride, chloroform, ethyl chloride, poly-
vinyl chloride, and various fluorocarbons (Freons). ' When heated, chlori-
nated hydrocarbon vapors react with oxygen or water to form chlorine, hydro-
gen chloride, phosgene, and other toxic substances; therefore, incineration
used for the control of volatile organic compound emissions can become an
inadvertent source of phosgene emissions. A properly operated caustic
scrubber can reduce phosgene emissions in exhaust gases from the incineration
of chlorocarbons.
The potential for phosgene generation by chlorocarbon decomposition
exists at chlorocarbon producing facilities, metallurgical operations, dry-
cleaning and degreasing facilities, certain types of industrial fires, and
wherever solvents contact heat or ultraviolet light.
10
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REFERENCES FOR SECTION 3
1. Kirk-Othmer. Encyclopedia of Chemical Technology. 3rd Ed., Volume 17.
Wiley Interscience Publication, New York. 1979. pp. 416-425.
2. U.S. Department of Health, Education, and Welfare. Occupational Diseas-
es - A Guide To Their Recognitibn. June 1977. i
3. U.S. Environmental Protection Agency. Office of Pesticides and Toxic
Substances. Phosgene. Chemical Hazard Information Profile. June 1977,
pp. 226-236. :
4. SRI International. 1983 Directory of Chemical Producers, USA. 1983.
5. Faith, Keyes, and Clark's Industrial Chemicals. Phosgene. 4th Ed.
John Wiley & Sons. November 1975. pp. 624-627. .
6. Smith, A. J. Measurements of Some Potentially Hazardous Organic Chemi-
cals in Urban Environments. Atmospheric Environment, 15:601-612, 1981.
Pergamon Press, Ltd., Great Britian.
7. Singh, H. B. Phosgene in the Ambient Air. Nature, 264:428-429,
December 2, 1976.
8. Bjerre, A. Mathematical Modelling in the Hazard Assessment of Sub-
stances Forming Toxic Decomposition Products. The Example of Carbon
Tetrachloride. Annals of Occupational Hygiene, 24(2):175-183, 1981.
Pergamon Press, Ltd., Great Britain.
11
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SECTION 4
PHOSGENE EMISSION SOURCES
i
This section describes industrial processes that are sources of phosgene
emissions, including direct phosgene production and the; use of phosgene as an
intermediate in the production of isocyanates, polycarbonates, carbamates,
thiocarbamates, and phenyl ureas. Included are process descriptions and
emission estimates for hypothetical facilities involved in the making or .use
of phosgene. Because the production of chloroformates and chlorocarbonates
represents a minor end use of phosgene, this is not described. The processes
and the phosgene emissions and controls associated with the production of
these'chemicals, however, are similar, to those described for polycarbonate
production (Section 4.3).
Most phosgene is produced for onsite consumption, with merchant phosgene
accounting for less than 2 percent of total production.1 Hence, phosgene
production operations will generally be found at facilities engaged in the
manufacture of isocyanates, polycarbonates, carbonates, etc. The production
of phosgene is discussed in Section 4.1, and the use of,phosgene as a chemi-
cal intermedate, in the following sections. For economy, .the discussion of
phosgene production is not repeated in each of the sections in which its
intermediate uses are discussed. Instead, the reader should refer back to
Section 4.1.
4.1 PHOSGENE PRODUCTION <
4.1.1 Process Description
Phosgene is produced by the reaction of carbon monoxide and chlorine
over a highly absorptive activated charcoal catalyst at 200°C and 14 to 28
kPa (2 to 4 psig): '
CO + C12 + COC12 (1)
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The reaction is rapid and exothermic. Because phosgene decomposes at temper-
atures above 300°C, a water-cooled reactor is used to remove the excess heat.
Figure 2 presents a flow diagram of the production of phosgene from carbon
monoxide and chlorine.
Phosgene production is continuous and highly automated and proceeds as
follows:
0 • Preparation and purification of carbon monoxide
0 Preparation and purification of chlorine
0 Metering and mixing of reactants
0 Purification and condensation of phosgene
0 Control of phosgene emissions to assure worker and environmen-
tal safety
Carbon monoxide may be manufactured either by the reduction of carbon
dioxide over coal or carbon .or by the controlled oxidation of hydrocarbon
fuels. Chlorine is usually purchased from manufacturers who use the electro-
lysis of sodium-chloride brines (caustic chlorine process). These reactants'
must be pure* Objectionable impurities include water (which can produce hy-
drogen chloride, hydrocarbons, and hydrogen that may trigger a reaction
between chlorine and steel and destroy the equipment), sulfides (which can
produce undesirable sulfur chlorides), and other impurities (which could de-
activate the catalyst).
As shown in Figure 2, carbon monoxide (Stream 1) and chlorine (Stream 2)
are mixed either in equimolar proportions'or with a small excess of carbon
monoxide to ensure complete conversion of the chlorine. The product gases
(Stream 3) are condensed, the liquid phosgene (Stream 4) is sent to storage,
and the remaining gases (Stream 5) are scrubbed with a hydrocarbon solvent to
remove residual phosgene. Uncondensed phosgene and the solvent that is used
in the scrubber may be used for subsequent processing (e.g., in the produc-
tion of isocyanate).
The liquid phosgene is stored in pressurized steel tanks. A typical
precautionary measure is to store the material in two tanks, neither of which
is filled to more than half of its capacity.2 This allows the transfer of
the phosgene to either tank in case a leak develops in one of the tanks or
its piping system.
13
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4.1.2 Emissions and Controls
Phosgene emissions fall into three categories—process emissions (includ-
ing storage tank vents which are exhausted to the control system), fugitive
emissions, and emissions that occur during process upsets. Each type is dis-
cussed, estimates are presented, and controls are explained. The development
of emission estimates "is discussed further in the appendix.
Process Emissions--
All process emissions from phosgene production and utilization are typ-
ically routed to a caustic scrubber. The caustic scrubber is the control of
choice because phosgene is rapidly and completely destroyed fay aqueous sodium
hydroxide, as shown in the.following reaction:
COC12 + 4NaOH •»• 2NaCl + Na2C03 + 2H20 (2)
The sodium hydroxide concentration should be maintained at between 3 and
8 weight percent, and the sodium chloride and sodium carbonate must not pre-
cipitate and clog the reactor. It should be noted that the solubility of
2
these components is appreciably lower in caustic solution than.in water.
These requirements are met by-continually replacing the solution in the
scrubber with fresh caustic solution. Data generated by the U.S. Army indicate
that a two-stage scrubber can reduce phosgene emissions to below 0.5 ppm by
•}
volume. This study demonstrated that phosgene control is severely reduced
if 1) the phosgene flow to the scrubber exceeds the design capacity of the
scrubber, or 2) the caustic concentration in the scrubber is not maintained
between 3 and 8 weight percent. The design of the scrubber therefore must be
such that it can accommodate any phosgene surge. It is estimated that a
phosgene plant producing 200 million pounds per year would emit 300 pounds
per year after scrubbing. ~
Figures 3a and 3b present flow diagrams for phosgene emission control
systems. Figure 3a shows a possible control system for a plant that produces
phosgene for sale without any subsequent onsite processing. Control can be
achieved with a single caustic scrubber. Figure 3b shows an emission control
system for a plant that produces phosgene and then processes it on site to
produce other products. These subsequent operations generate additional
emissions that must be controlled.
15
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PLANT STACK
EXHAUST
COC12 FROM
PURGE VALVES
(See Figure 2)
CAUSTIC
SCRUBBER
t
CAUSTIC SPENT
CAUSTIC:
Figure 3a. Flow diagram of a phosgene emission control system for
merchant" phosgene operations.
16
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CD
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In all commercial phosgene processes, the chlorine atoms react with
active hydrogen atoms to produce hydrogen chloride (HC1). Hydrogen chloride
is an acid gas, and like phosgene, it can be controlled with a caustic
scrubber; however, it is usually desirable for a water scrubber to precede the
caustic scrubber. This not only permits HC1 to be recovered as a byproduct,
but.also reduces the loadings to the caustic scrubber. The production of
toluene diisocyanate includes a nitration step that generates acidic nitrogen
and sulfur oxide emissions, which would be routed to a caustic scrubber.
These reactions take place in an organic solvent medium, and the solvent is a
source of volatile organic compound (VOC) emissions. Solvents include
chlorinated compounds such as methylene chloride, monochlorobenzene, and
ortho-dichlorobenzene, as well as pyridine, xylene, methanol, and aliphatic
hydrocarbons. Whereas VOC can be controlled by incineration, the incineration
of chlorinated VOC can produce hydrogen chloride, chlorine, and phosgene emis-
sions. Therefore, a second caustic scrubber is required in series with the
incinerator.
Fugitive Emissions— \
Pumps and valves are the major sources- of fugitive phosgene emissions at
facilities where phosgene is produced or used. No compressors are used on
phosgene process flows, and emissions from flanges andidrains are considered
negligible. Because phosgene is known to be very toxic, industry typically
takes measures to minimize fugitive emissions. These measures include:4
1. Welding pipe joints and monitoring of the quality of all welds.
2. Enclosing the reactor and condenser in a negative-pressure build-
ing, and venting the exhaust to the caustic scrubber.
3. Employing special construction materials and techniques for all
piping and valves handling hazardous or corrosive substances.
Installing plugs or caps on all open-ended lines and plug
valves to minimize stem leakage.
4. Enclosing pump couplings and drivers on all pumps handling phos-
gene. Using special mechanical seals on other pumps (dual seals
with barrier fluids) and closed purge sampling systems.
5. Continuous area and individual monitoring and the installation
of phosgene-release alarms.
6. Establishing procedures and training for prompt response to
phosgene leaks and releases.
18
-------
7 Practicing intensive preventive maintenance during plant shut-
downs and turnarounds. (A turnaround is a planned shutdown to
allow equipment to be used to make a different product.)
All plants that produce and use phosgene have individual and/or area
monitors to detect excessive phosgene levels in plant air. " Based on the
sensitivity of these alarm systems, the fugitive phosgene emissions from a
phosgene plant producing 200 million Ib/yr are estimated to be 120 Ib/yr or
0.6 Ib/million Ib of phosgene.
Alternatively, this emission rate can be estimated by counting the
valves, pumps, and flanges at a typical plant and applying the fugitive leak
rates and control efficiencies developed by the Environmental Protection
Agency for the synthetic organic chemicals manufacturing industry (SOCMI).
This approach yields an estimated fugitive emission rate of 6600 Ib/yr, or 33
Ib/million Ib of phosgene produced. Fugitive emission estimates by both the
monitoring approach and the equipment count/emission factor approach are
presented hereafter as a range for each plant. It is observed, however, that
fugitive controls used in phosgene production are actually much more strin-
gent than those reported in Reference 10. .
In phosgene plants where the reactor" and condenser are enclosed in a
negative-pressure building and the exhaust is vented through the caustic
scrubber, 99 percent of the fugitive phosgene emissions are destroyed in the
caustic scrubber, and phosgene emissions are further reduced to an estimated
1 to 66 Ib/yr (0.005 to 0.3 Ib/million Ib phosgene produced). Fugitive emis-
sion estimates are derived in the appendix.
Process Upsets—
Some phosgene emissions result from process upsets, e.g., pump failures
and inadvertent opening of the wrong valve. Based on 15 process upset re-
ports during a recent 6-year period,' three Texas plants released a total- of
900 pounds of phosgene. Phosgene releases in the 15 episodes ranged from 1
to 220 pounds. The stated amount released in each case usually represented
an estimate, and it often was not clear what part of the process was in-
volved. For example, one upset was reported as a ruptured line. Based on
the size of these three plants, the total phosgene releases and the number of
releases of phosgene (and assuming all releases were reported), it is esti-
mated that a plant producing 200 millions pounds per year of phosgene will
19
-------
average one process upset per year during which 50 pounds of phosgene is
released (0.0005 Ib/ton phosgene produced).
Total Phosgene Emissions-
Total phosgene emissions for a plant that produces 200 million pounds of
phosgene a year is estimated to be 470 to 7000 pounds, comprising 300 pounds
from the process vents, 120 to 6600 pounds in the form of fugitive emissions,
and 50 pounds as a result of process upsets. This is equivalent to 2.35 to
34.8 Ib phosgene emissions per million pounds of phosgene produced. Table 3
presents a summary of phosgene emissions from phosgene production.
TABLE 3. ESTIMATED PHOSGENE EMISSIONS FROM A HYPOTHETICAL PHOSGENE PLANT3
(lb/yr)
Process vent
emissions
300
Fugitive
emissions
120 to 6600
Emissions due
to upsets
50
Total
emissions
470 to 6950
Eimission factor,
Ib per million
Ib processed
2.35 to 34.8
Based on facilities with a hypothetical rate of 200 million pounds of phos-
gene production per year. .
Incinerator and scrubber exhausts. .
Estimated fugitive emissions would be reduced by a factor of 100 if reactor
and condenser are enclosed in a negative-pressure building and vented
through a caustic scrubber.
4.2 ISOCYANATE PRODUCTION11'12
4.2.1 Process Description
The commercial production of aromatic and aliphatic isocyanates is accom-
plished through the reaction of amines and phosgene. Aromatic isocyanates are
more important commercially than aliphatic isocyanates. In 1978, the esti-
mated world production of the two principal aromatic isocyanates was 635,000.
metric tons of toluene diisocyanate (TDI) and 454,000 metric tons of diphenyl-
methane-4,4'-diisocyanate (MDI).
i
Aromatic Diisocyanate Production-
Figures 4 and 5 show the reaction sequences for the production of the
major aromatic diisocyanates. Toluene (Stream 1) is the starting material for
20
-------
O LiJ
2: S
1—1 UJ
O vo
I—.
CO f-
»=> U.
o D:
O O 0)
> oo a>
oo
a;
3
O)
o c:
c
(O O
•r- j;
•a a.
O)
•a
2 =
0-4->
e o
3 o
o
(fl S-
C Q-
to +J
(U t»_
0-0
O &-
•i—
-------
L
' H-
u < i
LJU < :
3 >- £
i r ^ c
__
_J
D
2
— N
o o 5
t— CO Q-
i— i
— N
fit
UJ
O o: i.
/"""N UJ 3
V y cj CQ T~
v- o => u_
> ce
o 01
CO O>
-i^.
J^
i j
?
o
t^H
H-
•wj
_l
I— 1
I—
CO
^^
a
i
yQ^
XT
V1
o:
CMLU — •
i — ca 10
<_> CQ
U
S
L
„
J Z C.
o
*""
1 —
LU
^*».
_J
C
y'WN
^Vl™~>
\/
LU
Z
LU
CZJ
CO
J
O O o
CO
• <-; o o
u
S/
O 3D 0)
<_> o: s.
O 3
"00 01
— , C_J .—
^ o a: u_.
J ac c
1 0- r-
j
yfvjv
2> LU -v-
t— .
«ea; o
r— 3 CO
O ^_~
= 0
x
f
9>.
3
H
v_'
- a.
^^^^
•^
cs
r~-
U
o
C_)
O
LU
I—
U
«c
LU
OH
s:
^>
LU Z tj
O O °
?pS
^ C3 -
S°S
u. n: ^
a. •
H*
LU
2
LU
C3
CO
o
a:
^-
^^
^
LU
^>
O
LU
a;
v-~~
^CM
01
S-
3
C7>
•r~
1 1
UB
E
O
i.
Lu
>-
ec.
LU
^
O
o
LU
a:
o
i—
CM
CD
3
cn
•^»
u.
o
u.
in
w
4)
u
Vf
(.
0)
-l->
ai
a. ai
tr
J
4-1
O
•4->
(.
ai
•ai
t.
1
W
.*.
<4-
•r-
f
4J
C
I/I
a
E
c
01
1—
1 1
UJ
L_
0
.
4J
•a
t/1
OJ
trt
in
C w*
in
&>
u
0
&.
4)
J=
41
•W
m
in
4>
41
4-> i
in
3?':
"o
i i
C
o
u
o
c ,i
vi ;'
>,
J
(O
gj |'
« 1
!
!
. '
•
(U
(O
c
lO
o
CO
•^
•r*
^
C
<1)
3-— •
^^ ,
o ai
1J M«
ai
«»- cn
O CO
o
o a.
4J CO
U O)
3 CO
o
S_ CO
a_ co
^*
•a -i->
CO «*-
3 O
CO 4->
C S-
O fO
•r- 0.
03 CO
a>'Jc
Q-J—
0*-'
CJ
•r-
CO
ra
CQ
S
22
-------
the production of TDI and 3,3'-dimethyldiphenylmethane 4,4'-diisocyanate.
Toluene is converted' to dinitrotoluene with a mixture of solvent (Stream 2)
and sulfuric and nitric acids (Stream 3). (The sulfuric acid ties up water
formed in the reaction.) The proportions of dinitrotoluene isomers prepared
can differ depending upon operating conditions. Varying the mixture of
isomers allows flexibility in the properties of the diisocyanate polymers:
0 When dinitrotoluene is made without separating the mononitrotoluene
isomers (Stream 5), the resulting mixture is 80 percent 2,4-isomer
and 20 percent 2,6-isomer.
0 The nitration reaction can be interrupted after the formation of the
mononitrotoluenes (Stream 4), and the ortho- and paramononitrotolu-
enes (Streams 6 and 7) can be separated by distillation. Nitration
of paranitrotoluene yields 100 percent 2,4-dinitrotoluene.
0 Nitration of orthonitrotoluene yields a mixture of 65 percent 2,4-
dinitrotoluene and 35 percent 2,6-dinitrotoluene (Stream 8), Alter-
natively, orthonitrotoluene can be reduced to orthoaminotoluene (not
shown in Figures 4 and 5) and form benzidine through the benzidene
rearrangement. Benzidene can then be phosgenated to form 3,3'-toli-
dene 4,4'-diisocyanate.
.The nitrotoluenes (Stream 8).are reduced to the amines with hydrogen
(Stream 9). The aminotoluenes (Stream 10) react with phosgene
(Streams 11 and 13) to form the isocyanates in a two-step phosgena-
tion process shown in Figure 5. Phosgene is first added at a tem-
perature range of -20° to 60°C and again at 100° to 200°C. Polymer-
ization takes place immediately, but some monomers remain. The pro-
duct (Stream 14) is then distilled-to remove and recover solvent and
unreacted monomer.
Aliphatic Diisocyanate Production—
Diphenylmethane-4,4'-diisocyanate,.an aliphatic diisocyanate, is pro-
duced by reacting two moles of analine with one mole of formaldehyde, fol-
lowed by phosgenation-of the diamine and polymerization of the resulting
diisocyanate. The reaction and process conditions are similar to those for
the formation of TDI.
The phosgenation and polymerization reactions are carried out in a
solvent medium. Although the role of the solvent is unknown, the choice of
12
solvent influences the rate and extent of the reaction. The solvent must
dissolve the amines, phosgene, isocyanate monomers9 and at least the lower
23
-------
molecular weight polymers. Typical solvents are aromatic compounds such as
xylene, monochlorobenzene, and o-dichlorobenzene. Aliphatic solvents such as
methanol or hydrocarbons may be added to precipitate the polymer from solu-
tion. ;
Process economics require that the solvents be recovered and recycled.
All phosgene used in the process reacts with active hydrogen atoms to form
hydrogen chloride, which is recovered and either sold or decomposed by elec-
trolysis to yield chlorine (used in the production of phosgene) and hydrogen
(used to reduce nitro compounds to amines). ;
4.2.2 Emissions and Controls
Potential process emissions from the production of isocyanate include
phosgene, hydrogen chloride, aromatic and aliphatic solvents, aromatic
amines, aromatic nitro compounds, isocyanates, nitrogen oxides, and sulfur
oxides. Because these emissions include a number of toxic and corrosive
chemicals, controls are necessary. A typical control system (as shown in
Figure 6) would include: '
1. A water scrubber to remove and recover hydrogen chloride.
2. A caustic scrubber to provide removal of VOC and COC12 from the
water scrubber as well as to remove VOC from the nitration and
distillation processes. !
3. An incinerator for volatile organic compounds.
4. A second caustic scrubber for treatment of the incinerator exhaust
to remove residues from the combustion of chlorinated hydrocarbons.
HC1, VOC, COC12
(See Figure 5)
i
(A)®©©
VOC, NOV
f\
(See Figures
•4 45)
t
WATER
SCRUBBER
CAUSTIC
SCRUBBER
A
1 I ,
INCINERATOR
I ;
WATER RECOVERED CAUSTIC SPENT FUEL
HC1 CAUSTIC AIR
->
CA
STACK
EXHAUST
t
CAUSTIC
SCRUBBER
B
t 1
LISTIC SPENT
CAUSTIC
Figure 6. Flow diagram of a phosgene emission control system.
24
-------
As shown in Table 4, total annual phosgene emissions, after controls,
are estimated to be 705 to 9760 pounds for a plant producing 200 million
pounds of phosgene and using it on site in the production of TDI. This
estimate includes emissions from phosgene production, which were developed in
the preceding section and are not reported here. Almost always, phosgene is
produced at the same plant where phosgene derivatives, such as isocyanates,
are produced.
TABLE 4. ESTIMATED PHOSGENE EMISSIONS FROM A HYPOTHETICAL TOLUENE
DIISOCYANATE PLANT USING PHOSGENE PRODUCED ON SITEa
(Ib/yr except as noted)
Phosgene
production
Toluene
diisocyanate
production
Total plant
Process vent
emissions
300
150
450
Fugitive
emissions
120 to 6600
60 to 2640
• • *
180 to 9240
Emissions
due to
upsets
50
25
.
75
Total
emissions
470 to 6950
235 to 2820
705 to 9760
Emission
factor, Ib
per million
Ib phosgene
produced
2.35 to 34.8
1.18 to 14.1
3.53 to 48.9
aBased on facilities with a hypothetical rate of 200 million pounds of phos-
gene production per year.
Incinerator and scrubber exhausts.
Estimated fugitive emissions would be reduced by a factor of 100 if reactor
and condenser are enclosed in a negative-pressure building and vented through
a caustic scrubber.
Derivation of phosgene emissions from TDI production is documented in the
appendix.
4.3 POLYCARBONATE PRODUCTION14'15
4.3.1 Process Description
In general, polycarbonates are formed by the reaction of a diol (a mole-
cule with two alcohol groups) and a carbonic acid derivative (phosgene is the
25
-------
chloride of carbonic acid). Because most commercial polycarbonates are de-
rived from the reaction of bisphenol A [2,2 bis(4-hydroxyphenyl) propane] and
phosgene, this process is discussed here. Polycarbonates can also be formed
by the reaction of other aromatic or aliphatic diols (dihydroxy alcohols) and
phosgene.
;i
The sequence of reactions for producing polycarbonate from bisphenol A
and phosgene is presented in Figure 7. The basic reaction is:
0
II
OH + COC12 * [0-(0)-C —(0)— 0-C-O] + 2HC1 (3)
Bisphenol A and 1 to 3 mole percent monofunctional phenol (to control the
molecular weight of the carbonate polymer) are dissolved or slurried in aque-
ous sodium hydroxide (Stream 1). A solvent and a tertiary amine catalyst
(such as pyridine) are added, phosgene gas is bubbled in (Stream 2), and the
resulting mixture.is vigorously stirred. Additional caustic is added as
needed to keep the mixture basic. As the polymer is formed, it is filtrated
in the solvent layer. When the reaction is completed, the aqueous phase
(Stream 3) contains sodium chloride, sodium carbonate (formed by a side reac-
tion of phosgene and caustic), and possibly traces of phenols. The organic
phase (Stream 4) is a polymer solution containing polycarbonate, residual
catalyst, and solvent. This polymer solution is washed with water, extracted
with acid to remove residual catalyst (Stream 5), and washed again (Stream 6)
with water until neutral (Stream 7). The solvent-is then stripped from the
polymer, by evaporation (Streams 8 and 9). These reactions take place at or
about room temperature. The reaction may also be carried out in a solvent
medium in which a large quantity of pyridine is used to tie up the hydrogen
chloride formed by the reaction of phosgene and bisphenol A.
Possible solvents (Stream 1) include methylene chloride, aromatic liquids,
.chlorinated aromatic liquids, and aliphatic chlorohydrocarbons. Process
economics require the recovery and recycling of all organic solvents.
Most of the processing conditions (including reaction conditions) are
closely guarded secrets, particularly with regard to processes for isolating
26
-------
UJ
O \—
1/1
o> *» is
u 0* o>
u *" j->
0.0) S
.c >
J=
•*-> "U *rt
c u< •
o «
1_ *-> 1- in
^s^s
t" .*-.
0> M O
HI f *J fc.
t +J C •!->
3 O) C
171 C > O
•^ 1- tj o
.c
0)
+->
(O
O
J2
(O
"O
o
O.
c
o
U
3
O
&.
Q-
O'
4-
ro
CD
to
O
(O
U
o
o.
«o a> >>
A <-> - =3 _J
re LU «_i u- <:
o. > nr <: CD s:
CO _l O I— Z O
»-«o «c us
a»-»-
i i. in u
4-1 m t.
w) -o ra
27
-------
the polymer from the solvents. Possible procedures for'separating polymers
and solvent include nonsolvent precipitation, spray-drying, multistep total
solvent evaporation, and partial or complete solvent removal in boiling water
followed by oven-drying. Total solvent evaporation is effected by the use of
wiped-film evaporators and multiport vacuum-vented extruders. The total re-
moval of a low-boiling chlorinated hydrocarbon (such as methylene chloride)
from a very high-viscosity, high-melting polymer is complicated fay two fac-
tors: 1) foam formation at low temperatures impedes heat and mass transfer,
and 2) the solvent can react with water or thermally decompose and cause prod-
uct contamination.
4.3.2 Emissions and Controls j
Potential emissions from phosgene and polycarbonate production include
phosgene, hydrogen chloride, aromatic and aliphatic hydrocarbons (some of
which are chlorinated and could produce phosgene on incineration), and phe-
nols. Emission controls for the reactors and solvent recovery systems include
incinerators and caustic scrubbers-. These controls are similar to those used
for isocyanate production. Figure 8 is a flow diagram of a control system.
(A) and (B)
VOC, COC12
(See Figure 7)
INCINERATOR
t
FUEL, AIR
CAU
A STACK
EXHAUST
CAUSTIC
SCRUBBER
e
t |
STIC SPENT
CAUSTIC
Figure 8. Control system for polycarbonate production.
The wastewater from the reactor, acid wash, and water wash (see Figure 7)
is acidic and may contain small amounts of organic compounds. These compounds
would probably have high molecular weights, have low water solubility, be non-
volatile, and thus would not be a significant source of lair emissions.
28
-------
As shown in Table 5, total annual phosgene emissions are estimated to be
580 to 8190 pounds for a plant producing 200 million pounds of phosgene and
using it on site to produce polycarbonates. Derivation of these emission
estimates is documented in the appendix.
TABLE 5. ESTIMATED PHOSGENE EMISSIONS FROM A
HYPOTHETICAL POLYCARBONATE PLANT USING PHOSGENE PRODUCED ON SITE
(lb/yr)
Phosgene
production
Polycarbonate
production
Total plant
—
Process vent
emissions
300
70
370
=
Fugitive
emissions
120 to 6600
30 to 1160
150 to 7760
Emissions
due to
upsets
50
10
60
Total
emissions
470 to 6950
110 to 1240
580 to 8190
Emission
factor, Ib
per million
Ib phosgene
produced
2.35 to 34.8
0.55 to 6.2
2.90 to 41.0
aBased>on facilities with a hypothetical rate of 200 million pounds of phos-
gene production per year. .
blncinerator and scrubber exhausts.
o
Estimated fugitive emissions would be reduced by a factor of 100 if reactor
and condenser are enclosed in a negative-pressure building and vented through
a caustic scrubber.
4.4 HERBICIDES AND PESTICIDES PRODUCTION14
Phosgene is used in the synthesis of some pesticides and herbicides.
The active chlorine atoms of phosgene react with hydrogen to produce hydrogen
chloride, and the carbonyl group (C=0) is added to the reacting molecule.
The three general classes of chemicals comprising herbicides and pesticides
are phenyl ureas, carbamates, and thiocarbamates. Sections 4.4.1 through
4.4.3 discuss the production of each of these classes of herbicides and
pesticides. The phosgene emissions from the production of each of these are
similar. (Phosgene emission estimates for herbicide and pesticide production
are presented in Section 4.4.4.)
29
-------
4.4.1 Production of Substituted Phenyl Ureas
The herbicidal activity of substituted phenyl ureas, was discovered in
the late 1940's. There are currently 20 to 25 phenyl ureas on the commercial
market. Although initially developed as industrial herbicides, they also
have been used in selective agricultural applications.
A general reaction for the substituted phenyl ureas (e.g., monuron) can
be written as follows:
0 > -NH-C-N-R
For monuron, x is hydrogen, y is -OC1, and R and R1 are CH3. Other
substituted phenyl ureas have been prepared and are in use with different
substituents for x, y, R, and R'.
Figure-9 presents the basic operations".used in substituted phenal urea
production, and Figure 10 presents a flow diagram of a control system for
such a process. The synthesis of monuron [3-(p-chloropheny])-l,l-dimethyl-
urea] is typical of the general commercial method used for the production of
substituted phenyl ureas. For this synthesis, the p-chloroaniline in dioxane
or some other inert solvent (Streams 1 and 2) reacts with anhydrous hydrogen
chloride and phosgene at 70° to 75°C (Stream 3) to form.pi-chlorophenyl iso-
cyanate (Stream 4). This aromatic isocyanate further-reacts with dimethyl-
amine at 25°C to give monuron (Stream 5), which is then separated from the
solvent by precipitation and evaporation. (See Reaction 4.)
M2 N = C = 0 ; NHCON (CH3)
to) +
COC12
(CH3),NH
Cl Cl
p-chloroanaline p-chlorophenyl isocyanate
30
3/2
-------
0) *J «
tj c
J= 0)
0> 4-> >
J=
•M "a *n
c •
S s. in
0) u> O
3 01 C
O) C > O
•r-1- U
<*- u>
•O in 10
vi at ai
i-
o
a: o
o L
UJ
S.
(U
a.
o
U
•I—
tfl
CO
03
=3
O)
31
-------
O'
O
3
•o
2
Q.
(U
o.
o
o
o
o
CO
O)
3
cn
32
-------
4.4.2 Carbamates Process
Carbamates are used as herbicides, insecticides, and medicinals, and for
the control of nematodes, mites, and mollusks. They are obtained either by
the reaction of a substituted analine with a chloroformate ester or the reac-
tion of an isocyanate with an alcohol. The chloroformate ester is made by
reacting phosgene with an alcohol (ROM + COCL2 •»• C1COOR + HC1), and the iso-
cyanate is made by reacting phosgene with an amine (as described in Section
4.2). The basic reactions are:
(5)
O - N = C = 0 +
(6)
Different R groups and substitutions on the benzene ring yield a variety of
useful products.
4.4.3 Thiocarbamates Process
Thiocarbamates are used primarily as herbicides, but some have value as
fungicides. The phosgene reaction is the same as in the other processes: the
chlorine atoms react with hydrogen to form hydrogen chloride, and the car-
bony! group is added to the molecule.
Thiocarbamates are formed in a two-stage reaction. The first stage is
the reaction of phosgene and a secondary amine to yield a carbamyl chloride:
R2NH + COC12 -»• R2NCOC1 + HC1 (7)
followed by reaction with a thiol to yield a carbamate:
R2NCOC1 + NaSR1 -> R2NCOSR' + NaCl (8)
Alternatively, the secondary amine can react with an alkyl chlorothiol formate
in the presence of a proton acceptor to tie up the HC1 formed in the reaction:
RSCOC1 + NHR'R" + RSCONR'R" + HC1 . (9)
33
-------
Varying the R, R', and R" groups will produce different thiocarbamates.
4.4.4 Emissions and Controls
Generalized flow diagrams for herbicide and pesticide production and
emission controls are shown in Figures 9 and 10, respectively. State-
of-the-art controls include incineration (to control VOC emissions) and
caustic scrubbers (to control phosgene and HC1 produced either by reactions
involving phosgene or by incineration of the VOCs).
As shown in Table 6, total annual phosgene emissions are estimated to be
580 to 8220 pounds for a plant producing 200 million pounds of phosgene on
site and using it to produce herbicides and pesticides. ! Derivation of this
emission estimate is documented in the appendix.
TABLE 6. ESTIMATED PHOSGENE EMISSIONS FROM A HYPOTHETICAL
HERBICIDE AND PESTICIDE PLANT USING PHOSGENE PRODUCED ON SITE9
(lb/yr)
Phosgene
production
Herbicide and
pesticide
production
Total plant
Process vent
emissions
300
70
370
Fugitive
emissions
120 to 6600
30 to 1190
150 to 7790
Emissions
due
to upsets
50
10
60
i
Total
emissions
470 to 6950
110 to 1270
i
580 to 8220
Emission
factor, Ib
per million
Ib phosgene
produced
2.35 to 34.8
0.55 to 6.4
2.90 to 41.1
Based on facilities with a hypothetical rate of 200 mill ion pounds of phos-
gene production per year.
Incinerator and scrubber exhausts.
Estimated fugitive emissions would be reduced by a factor of 100 if reactor
and condenser are enclosed in a negative-pressure building and vented through
a caustic scrubber.
34
-------
-------
REFERENCES FOR SECTION 4
1. Kirk-Othmer. Encyclopedia of Chemical Technology. 3rd Ed., Volume 17.
Wiley Interscience Publication, New York. 1979. pp. 416-425.
2.. Personal communication with R. L. Matherne, Ethyl .Corporation, Baton
Rouge, Louisiana, February 7, 1984. Based on Mr. Matherne's experience
at BASF Wyandott.
3. Kistner, S., et. al. A Caustic Scrubber System For The Control Of
Phosgene Emissions Design, Testing, and Performance. Journal of the Air
Pollution Control Association,.28(7):673-676,1978.
4. Enviro Control, Inc. Assessment of Engineering Control Monitoring
Equipment. Volume I. Prepared for the National Institute for Occupa-
tional Safety and Health, Cincinnati, Ohio, PB83-15269. Contract No.
210-79-0011, June 1981.
5. Personal communication with Marshall Anderson, General Electric Corpora-
tion, Mount Vernon, Indiana, February 8, 1984.
6. Personal communication with George Dinser, Mobay Chemical Company, Cedar
Bayou, Texas, February 8, 1984.
7. Personal communication with Mark Kenne, ICI Americas, Rubicon Chemical
Division, Geismar, Louisiana, February 14, 1984. ;
8. Personal communication with Jerry Neal, PPG Industries, LaPorte, Texas,
February 14, 1984.
9. Personal communication with George Flores, Dow Chemical Co., Freeport,
Texas, February 15, 1984.
10. U.S. Environmental Protection Agency. Fugitive Emission Sources of
Organic Compounds - Additional Information on Emissions, Emission Reduc-
tions, and Costs. EPA-450/3-83-010. Research Triangle Park, North
Carolina. April 1982. '
11. Personal communication with R. A. Campbell, Plant iManager, Olin Chemi-
cals Group, Moundville, West Virginia, May 3, 1984.
12. Kirk-Othmer. Encyclopedia of Chemical Technology. 3rd Ed., Volume 13.
Wiley Interscience Publication, New York. 1979. pp. 789-808.
35
-------
13. Encyclopedia of Polymer Science and Technology. Volume 11. Wiley Inter-
science Publication, New York. 1979. pp. 507-525. .
14. Kirk-Othmer. Encyclopedia of Chemical Technology. 3rd Ed., Volume 18.
Wiley Interscience Publication, New York. 1979. pp. 479-492.
15. Encyclopedia of Polymer Science and Technology. Volume 10. Wiley Inter-
science Publication, New York. 1979. pp. 710-764.
16. Kirk-Othmer. Encyclopedia of Chemical Technology. 3rd Ed., Volume 12.
Wiley Interscience Publication, New York. 1979. pp. 319-326.
36
-------
SECTION 5
SOURCE TEST PROCEDURES '.
No EPA Reference Method has been established for measuring phosgene;
however, the .NIOSH Manual of Analytical Methods contains a proposed method
for the collection and analysis of phosgene in air.1 This method involves
the reaction of phosgene with a solution of 4,4'-nitrobenzyl pyridine in
diethyl phthalate to produce a red color. The color reaction is measured in
a photometer.
In the NIOSH method, exhaust or air containing phosgene is passed through
midget impingers (Figure 11) containing a color reagent made up of 2;5 g
4,4'-nitrobenzyl pyridine, 5 g N-phenylbenzyl amine, and 992.5" g diethyl phtha-
late. Fifty liters are drawn through the impingers if the phosgene level is
in the range of 0.04 to 1 ppm, whereas a volume of 25 liters is drawn for
phosgene levels above 1 ppm. The phosgene reacts with the reagent to form a
red color. The N-phenylbenzyl amine in the solution stabilizes the color and .
increases the sensitivity. The resulting red color should be measured with a
photometer within 9 hours of sampling. Sampling efficiency is 99 percent or
better.
Interfering compounds are acid chlorides, alkyl and aryl derivatives
(which are substituted by active halogen atoms), and sulfate esters. If
necessary, most of these interfering compounds can be removed in a prescrubber
containing an inert solvent, such as Freon-113, that has been cooled by an
ice bath. This method has not been validated by EPA.
37
-------
OJ
-------
REFERENCES FOR SECTION 5 I
1. National Institute for Occupational Safety and Health. NIOSH Manual of
Analytical Methods. Part 1 - NIOSH Monitoring Methods, Volume 1. U.S.
Department of Health, Education, and Welfare, Cincinnati, Ohio. April
1977.
2. Knoll, J. Intra-agency memorandum to T. Lahre, U.S. Environmental
Protection Agency, Air Management Technology Branch, Research Triangle
Park, North Carolina, December 4, 1984.
39
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-------
APPENDIX !;
PHOSGENE EMISSIONS DATA '
About 89 percent of the phosgene production capacity in the United
States is located in West Virginia, Louisiana, and Texas.1 In an effort to
obtain phosgene emissions data, several plants and their respective air con-
trol agencies in these States were contacted. Plants iin two other states
were also contacted. The Texas Air Control Board (TACB) files were also
reviewed for information on the Texas plants. Only one direct measurement of
phosgene emissions was found, but the companies had made conservative calcu-
lations of phosgene emissions. In one case, emission calculations were.based
on the sensitivity of in-place monitors; no phosgene was actually detected.
Engineering estimates submitted to state air control agencies by eight
phosgene producers range from 0 to 7.0 tons of phosgene per year. These
estimates contained no breakout of emissions due to phosgene production,
storage, use, etc., and the manufacturers did not indicate any basis for the
estimates. .
Compounds other than phosgene that must be controlled include process
solvents, reactants, intermediate products, chlorine, carbon monoxide, and
hydrogen.chloride (the latter is included unless phosgenation is carried out
in an alkaline medium). Most of these compounds are subject to Occupational
Safety and Health Administration (OSHA) regulations. A!typical plant's
emission control system will include the following:
1. A water scrubber to remove and recover hydrogen chloride for sale
or reuse. t
2. A caustic scrubber to control acidic gases, hydrogen chloride, and
phosgene. A backup scrubber, installed as a spare, is used if the
primary scrubber malfunctions.
3. An incinerator to control volatile organic compounds (some may con-
tain chlorine) and carbon monoxide. If both caustic scrubbers
malfunction, the phosgene will be routed directly to the incinerator
for destruction.
A-l
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4. An additional caustic scrubber that treats the incinerator exhaust
to remove residues from the combustion of chlorinated hydrocarbons.
In some plants where only one caustic scrubber is used, it is
located downstream of the incinerator.
5. For fugitive emissions, plugs or caps on open-ended lines, closed
purge sample systems, dual seals with barrier fluids on pumps, and
vent systems and rupture disks on safety relief valves. Phosgene
plants are also typically enclosed in negative-pressure buildings,
which may be vented to caustic scrubbers.
The following three types of emissions are found within a phosgene plant:
1. Process vent emissions—These are emissions from reactors, other
processing equipment (including storage tanks), and emission con-
trol equipment, including incinerator and scrubber exhausts.
2. Process upsets emissions—These emissions represent inadvertent
releases due to equipment failures and human error.
3. Fugitive emissions—These emissions represent releases due to leaks
in pumps, valves, and other phosgene handling equipment.
Phosgene Emission Estimates
Estimates of .total phosgene emissions from plants producing 200 million
pounds of phosgene per year (a capacity chosen to represent production from a
large plant) are as follows:
1. From a plant producing phosgene for sale, 470 to 6950 Ib/yr.
2. From a plant producing phosgene and converting it to toluene diiso-
cyanates, 705 to 9760 Ib/yr.
3. From a plant producing phosgene and converting it to polycarbon-
ates, 580 to 8190 Ib/yr.
4. From a plant producing phosgene and converting it to herbicides,
580 to 8220 Ib/yr.
The emission factors on which these estimates are based (in terms of pounds
of phosgene emitted per million pounds of phosgene processed) are presented
in Table A-l.
Phosgene emissions from processes that consume phosgene (TDI, polycar-
bonate, herbicide, and pesticide production) have been estimated by comparing
the processes used to produce these chemicals with the process for phosgene
A-2
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TABLE A-l. SUMMARY OF ESTIMATED PHOSGENE EMISSIONS FROM
HYPOTHETICAL PHOSGENE AND PHOSGENE DERIVATIVE PRODUCTION FACILITIES3
1. Phosgene production
at a merchant phos-
gene plant
2. Toluene diisocya-
nate production
3. Polycarbonate pro-
duction
4. Herbicide and pes-
ticide production
5. Total for TDI .
plant (1 + 2)d
6. Total for polycar- ,
bonate plant (1 + 3)
7. Total for herbi- .
cide plant (1 + 4)a
Process
vents'
Ib/yr
300
150
70
70
450
370
370
Upsets ,
Ib/yr
50
25
10
10
75
. 60
. 60
Fugitive
emissions,
lb/yrc
120 to 6600
60 to 2640
30 to 1160
30 to 1190
180 to 9240
i
150 to 7760
150 to 7790
Total
emissions,
Ib/yr
470 to 6950
235 to 2820
110 to 1240
110 to 1270
705 to 9760
580 to 8190
580 to 8220
Emissions,
ID/million
Ib phosgene
produced
2.35 to 34.8
1.18 to 14.1
0.55 to 6.2
0.55 to 6.4
3.53 to 48.8
2.90 to 41.0
2.90 to 41.1
Based on facilities with a production rate of 200 million pounds of phosgene
per year.
Incinerator and scrubber exhaust.
Fugitive emissions would be reduced by a factor of 100 if process reactor
and condenser are enclosed in negative-pressure buildings and vented through
the caustic scrubber.
Emissions from intermediate production are added to those from the phosgene
production operations to estimate total plant emissions.
A-3
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production and then using engineering judgment to estimate the emissions
relative to those for phosgene production. The processes were compared with
respect to operations where phosgene might still be present and potential
emission sources. For example, emissions due to TDI production were estimated
to be one-half of those due to phosgene production, and those for polycarbonate
production and herbicide and pesticide production were estimated to be about
25 percent of those due to phosgene production. The TDI estimates are higher
because two phosgenation stages are required (Section 4.2) as compared with
one phosgene reaction step for polycarbonate (Section 4.3) and herbicide and
pesticide production (Section 4.4).
Phosgene emissions from phosgene consuming processes would be expected
to be significantly lower than those from the phosgene production process.
Phosgene is only used early in the process and is almost completely consumed.
No provisions for phosgene recovery and storage after production are needed.
Therefore, it is reasonable to expect phosgene production to be the major
source of phosgene emissions.
Basis For Emission Estimates
The emission estimates in Table A-l are approximations based on. limited
information, derived as shown below:
Process Emissions—
Process emission estimates were based on the following:
1. An assumed phosgene concentration of 0.5 ppm in the caustic scrub-
ber effluent, based on a U.S. Army study.2 This study indicates
that actual phosgene concentrations in scrubber exhausts could be
either significantly higher or lower, depending on whether the
scrubber is properly designed and operated. The range was 0.015 to
10.3 ppm. A scrubber would need to have the capacity to handle
phosgene surges.
2. Stack flow rates calculated from stack and exhaust velocity data
submitted to the Texas Air Control Board by the four Texas phosgene
producers.
3. Assumed plant operations of 24 hours a day, 330 days a year (90
percent availability).
A-4
-------
Based on this information, phosgene emissions of 19 to 500 pounds per year
were calculated for each of these plants. Thus, phosgene emissions from a
plant producing 200 million pounds of phosgene per year are estimated to be
300 pounds per year.
Fugitive Emissions (Based on Ambient Exposures)—
Individual and area, monitors of phosgene exposures yield the best avail-
able information about actual phosgene levels in plants: As standard equip-
ment at plants producing and handling phosgene, these monitors allow upper
limit estimations of ambient phosgene concentrations' and emissions.
Phosgene exposures are measured in ppm-minutes (the product of the phos-
gene concentration in parts per million and the time of exposure in minutes).
The maximum phosgene concentration that OSHA allows is 0.1 ppm for an 8-hour
day, or 48 ppm-minutes. Area monitors can respond to phosgene levels as low
as 0.05 ppm. Film badges are worn by all employees in phosgene areas. An
exposure of 5 ppm-minutes can be detected by a visible color change, and as
low as 2 ppm-minutes can be detected photoelectrically. Based on reported
data, photoelectrically detected color changes were infrequent—only five
occurrences over an 18-month period in a single plant.3J Other plants contacted
indicated that positive monitor responses were also infrequent. Because the
badges would detect exposures of 2 ppm-minutes, a steady-state phosgene
concentration of 1.2 ppm-minutes for an 8-hour shift was assumed.
Other assumptions included an indoor work area measuring 200 feet by 100
feet by 30 feet, 40 air changes per hour,4 and operated 24 hours a day, 330
days a year.
Process fugitive emissions = l'2 Ppm"m1" x 10"./ppm
8 h x 60 min/h
x 330 days/vr x 24 h/day x 40 changes/h x 6xl05 ft3/change x 98.92 Ib/lb-mole
= 120 Ib/yr
380 fr/lb-mole
This calculation yields a controlled process fugitive phosgene emission of
120 pounds per year. This is a conservative estimate because the steady-
state phosgene exposure is assumed to be constantly high throughout the
building for every working day during the year. :
A-5
-------
Fugitive Emissions (Based on Equipment Counts and Emission Factors)—
An alternative method can be used to estimate fugitive emissions; one
which applies emission factors to each valve, pump, etc., based on the phos-
gene content of each process stream. The following steps were followed in
this approach:
1. Develop a process flow diagram (see Figures 2, 5, 7, and.9 in .
text).
2. Identify all process streams containing phosgene.
3. Determine the phosgene content of each stream and whether phosgene
is present as liquid or vapor.
4. Identify and estimate the total number of fugitive emission points
(valves, pumps, and relief devices).
5. Estimate phosgene emission rates based on the probable degree of
control, assuming very stringent inspection and maintenance programs
and typical phosgene plant control measures for valves, open-ended
pipes,'pump seals, and vents.5
Fugitive emissions of phosgene and other volatile organics result from
leaks in process valve's, pumps, compressors, and pressure-relief devices.
For the four processes discussed (phosgene production, isocyanate production,
polycarbonate production, and herbicides and pesticides production) the phos-
gene emission rates are based on process flow diagrams, process operation
data, fugitive source inventories for hypothetical plants, and emission fac-
tors for process fugitive sources.
The first step in estimating fugitive emissions of phosgene entailed
listing the process streams in the hypothetical plants and then estimating
their compositions. For a reactor product stream, the estimated composition
was based on reaction completion data for the reactor and on the plant prod-
uct mix. For a stream from a distillation column or other separator, the
estimated composition was based on the composition of the input stream to the
unit, the unit description, and the general description of the stream of in-
terest (i.e., overheads, bottoms, or sidedraw).
After the process streams were characterized, the number of valves per
stream was estimated (based on the type of process). Pumps were assigned to
each liquid process stream, and relief devices were assumed on all reactors,
A-6
-------
columns, and other separators. No compressors are used on phosgene process
f1ows.
Emissions were then calculated for pumps, valves in liquid and gas line
service, and relief devices. Welded pipe joints are used in lieu of flanges,
and emissions from pipe joints are negligible.4 Fugitive emissions from a
particular source were assumed to have the same composition as the process
fluid to which the source is exposed. For example, phosgene emissions from
valves in liquid service were determined by taking the product of 1) the
total number of liquid valves in phosgene service,'2) the average phosgene
content of the streams passing through these valves, and 3) the average fugi-
tive emission rate per valve per unit time. Emissions from valves in gas
service and pumps were calculated in the same manner. For relief devices,
the composition of fugitive emissions was assumed to be the same as that of
the overhead stream from the reactor or column served by the relief device.
Emissions from the various fugitive types of sources were summed to obtain
total process fugitive emissions of phosgene.
Emissions from process fugitive sources depend on the number of sources
rather than their size; therefore, plant capacity does not affect total pro-
cess fugitive emissions. For this reason, overall emissions are expressed in
terms of kilograms per hour of operation. i
The estimates of fugitive phosgene emissions are presented in Tables A-2
through A-5. The emission factors used in these estimates are summarized in
Table A-6. At a hypothetical phosgene plant producing 200 million pounds of '
phosgene per year, the process fugitive emission rate is; 0..38 kg/h or 3000
kg/yr (3.3 tons/yr), assuming the plant operates 24 hours per day, 330 days
per year. For toluene diisocyanate production, estimated process fugitive
emissions are 0.15 kg/h or 1,200 kg/yr (1.3 tons/yr); for polycarbonate
production, 0.067 kg/h or 530 kg/yr (0.58 tons/ yr); and for herbicide and
pesticide production, 0.068 kg/h or 540 kg/yr (0.59 tons/yr), in addition to
the emission rate (determined above) associated with captive phosgene
production, if carried out at these facilities.
Reference 5, the basis for the emission factors and control efficiencies
in this analysis, does not consider fugitive emission controls as stringent
as those encountered in phosgene plants. For example, the most stringent
level level of control for valves cited in this report only involves monthly
A-7
-------
TABLE A-2. ESTIMATED FUGITIVE PHOSGENE
EMISSIONS FROM A HYPOTHETICAL PHOSGENE PLANT
PRODUCING 200 MILLION POUNDS OF PHOSGENE PER YEAR'
•
Emission source
Valves
Liquid
Gas
Pumps
Relief valves on:
COC12 reactor.
Condenser
Adsorption column
Storage tanks
•
Number
150
100
2
2
2
2
4
Uncon-
trolled
emission.
factor,
kg/h
0.0071/
valve
0.0056/
valve
0.0494/
pump
0.104
0.104
0.104
.0.104
Control h
efficiency, >c
%
59
73
100
100
100
100
100
Avg. COC12
content, •%
68
50
68
65
100
. 35
100
All sources
Emissions,
kg/h
0.30
0.08
0
0
0
0
0
0.38
a Process streams and their composition at hypothetical plant:
Process streams Phase % phosgene
Reactor to condenser Gas 65
Condenser to storage Liquid 100
Condenser to absorber Gas 35
Liquid phosgene to plant or shipment Liquid 100
Phosgene solution to plant Liquid 5
Reference 5.
c The control efficiencies are based on the use of plugs or caps on open-ended
lines, double seals with barrier fluids on pumps, vent systems and rupture
disks on safety relief valves, and a monitoring interval of at least monthly
for valves.
A-8
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TABLE A-3. ESTIMATED FUGITIVE PHOSGENE EMISSIONS
FROM A HYPOTHETICAL TOLUENE DIISOCYANATE PRODUCTION FACILITY3
Emission source
Valves
Liquid
Gas
Pumps
Relief valves on:
Phosgene line to
first-stage
phosgenator
Phosgene line to
second-stage
phosgenator
Unreacted phos-
gene to recycle
line
First-stage -
phosgenation
Second-stage
phosgenation
Distillation
column
Number
100
200
2
2
2
2
2
2
2
Uncontrolled
emission.
factor,
kg/h
0.0071/
valve
0.0056/
valve
0.0494/
pump
0.104
0.104
0.104
0.104
0.104
0.104
Control .
efficiency,'0
%
59
73
100
100
100
100
100
100
100
Avg. COC12
content, %
5
45
\ 5
85
I 85 .
5
5
1
\ l
All sources ;
Emissions,
kg/h
0.01
0.14
0
0
• o
0
0
0
0
0.15
Process streams and their composition at the hypothetical plant:
Process streams
Phosgene to first-stage phosgenation
Phosgene to second-stage phosgenation
Unreacted phosgene to recycle
Monoisocyanote to second-stage
phosgenation
Diisocyanate to distillation
Waste phosgene to scrubber
Phase % phosgene
Gas '
Gas
Gas
Liquid
Liquid
Gas
85
85
5
5
5
5
Reference 5.
The control efficiencies are based on the use of plugs or caps on open-ended
lines, double seals with barrier fluids on pumps, vent systems and rupture
disks on safety relief valves, and a monitoring interval of at least monthly
for valves.
A-9
-------
TABLE A-4. ESTIMATED FUGITIVE PHOSGENE EMISSIONS
FROM A HYPOTHETICAL POLYCARBONATE PRODUCTION FACILITY0
Emission source
Valves
Gas
Pumps
Relief valves on:
Phosgene line to
reactor
Unreacted phos-
gene to inciner-
ator
Number
100
0
2
2
Uncontrolled
emission
factor,
u
. kg/hb
0.0056/
valve
0
0.104
0.104 -
Control b
efficiency, '
%
73
0
100
100
Avg. COC12
content, %
44
0
85.
85
All sources
Emissions,
kg/h
0.067
0
0
0
0.067
a Process streams and their composition at the hypothetical plant:
Process streams Phase % phosgene
Phosgene to reactor Gas
Unreacted phosgene to incinerator Gas
85
2
Reference 5.
c The control efficiencies are based on the use of plugs or caps on open-ended
lines, double seals with barrier fluids on pumps, vent systems and rupture
disks on safety relief valves, and a monitoring interval of at least"monthly
for valves.
A-10
-------
TABLE A-5. ESTIMATED FUGITIVE PHOSGENE EMISSIONS FROM A
HYPOTHETICAL HERBICIDE AND PESTICIDE PRODUCTION FACILITY*1
Emission source
Valves
Gas
Liquid
Pumps
Relief valves on:
Phosgene line to
reactor
Unreacted phos-
gene to scrubber
Number
100
50
1
2
.
2
Uncontrolled
emission
factor,
kg/hb
0.0056/
valve
0.0071/
valve
0.0494/
pump
.0.104
0.104
Control .
efficiency, 'c
%
73
59
100
100
" 100
i
Avg. COC12
content, %
]
44
.1
1
i
85
2
All sources ,i
Emissions,
kg/h
0.067
0.001
0
0
0
0.068
Process streams and their composition at the hypothetical plant:
Process streams
Phosgene to reactor
Unreacted phosgene to incinerator
Aromatic isocyanate to second-
stage reactor
Reference 5.
Phase % phosgene
Gas
Gas
Liquid
"85
2
The control efficiencies are based on the use of plugs or caps on open-ended
lines, double seals with barrier fluids on pumps, vent systems and rupture
disks, on safety relief valves, and a monitoring interval of at least monthly
for valves.
A-ll
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TABLE A-6. PROCESS FUGITIVE
EMISSION FACTORS FOR PLANTS
Facility
Marketable phosgene
producer
Toluene diisocyanate
producer
Polycarbonate
producer
Herbicide and pesti-
cide production
Emission source
Phosgene production
Phosgene production
TDI production
Phosgene production
Polycarbonate production
Phosgene production
Herbicide and pesticide
production
Emission factor,
kg/h
0.38
0.15
0.38
0.067
0.38
0.0068
0.38
0.53
0.45
0.39
inspection and maintenance. This program provides 73 percent leak control
'for valves handling gases, and 59 percent leak control for valves handling
light liquids. A control efficiency of 100 percent, however, was estimated
for plugs and caps on open-ended lines, dual seals with barrier fluids on
pumps, and vent systems and rupture disks on safety relief valves. These
efficiencies were used to estimate fugitive phosgene emissions from valves,
pumps, and relief valves.
The emission factors from Reference 5 are based on "leaking" and "non-
leaking" sources. Leaking is defined as ""screening at or above 10,000 ppm
with a portable VOC monitor." Nonleaking is defined as "screening below
10,000 ppm." These data do not allow extrapolation to the actual level of
control most likely in phosgene plants. A 10,000 ppm phosgene concentration
could not be tolerated because the average lethal exposure is 400 to 500
ppm-minutes (concentration in ppm multiplied by exposure in minutes). The
current OSHA standard is 0.1 ppm. Phosgene plant monitoring equipment typi-
6-8
Film badges typical-
cally responds to concentrations of 0.02 to 0.2 ppm.
ly respond to exposures of 2 ppm-min0
The estimated fugitive phosgene emission rate of 120 Ib/yr based on the
monitoring approach from a facility with a capacity of 200 million pounds
A-12
-------
corresponds to 99.3 percent control of valve emissions. Considering that
phosgene concentrations of 0.02 to 0.2 ppm6"8 produce immediate responses
from monitoring equipment, this level of control seems achievable. Both
estimates of fugitive phosgene emissions, however, are presented in the
report to provide a range of fugitive phosgene emissions.
In plants where the reactor, condenser, and associated valves, pumps,
etc. are enclosed in negative-pressure buildings and the exhausts are vented
through a caustic scrubber, phosgene fugitive emissions will be reduced by a
factor of 100 from the above estimates.
Process Upsets— :
As discussed earlier, a search of the Texas Air Control Board files
yielded process upset reports for three producers of phosgene. Based on the
15 process upset reports during a recent 6-year period, the three plants had
a total phosgene release of 900 pounds. Phosgene releases in the 15 episodes
ranged from 1 to 220 pounds. The stated amount released in each case usually
represented an estimate. All releases may not have been reported. One
letter in the file responding to a Notice of Violation stated that the com-
pany was not obligated to report the release because none of the released
material (not phosgene) had left the company property. One of the 15 re-
leases led to-a fatality, and two other releases were responsible for lost-
time accidents. Based on the size of the plants, the total phosgene release,
and the number of releases of phosgene, it is estimated that a plant produc-
ing 200 'million pounds of phosgene per year will have one process upset per
year during which 50 pounds of phosgene is released.
A-13
-------
-------
REFERENCES FOR APPENDIX
1. SRI International. 1983 Directory of Chemical Producers, USA. 1983.
2. Kistner, S., et. al. A Caustic Scrubber System for the Control of
Phosgene Emissions Design, .Testing, and Performance. Journal Air
Pollution Control Association, 28 (7): 673-676, 1978.
3. Personal Communication with R. L. Matherne, Ethyl Corporation, Baton
Rouge, Louisiana, February 7, 1984, concerning Mr. Matherne's experiences
at BASF-Wyandotte.
4. Pollution Engineering Practice Handbook. P. N. Cheremisinof and R. A.
Young, eds. Ann Arbor Science, Ann Arbor, Mighigan. p. 212.
5. U.S. Environmental Protection Agency. Fugitive Emission Sources of Or-
ganic Compounds—Additional Information on Emissions, Emission Reduc-
tions, and Costs. EPA-450/3-82-010, 1982.
6. Personal communication with Marshall Anderson, General Electric Corpora-
tion, Mount Vernon, Indiana, February 8, 1984.
7. Personal communication with Jerry Neal, PPG Industries, LaPorte, Texas,
February 14, 1984. ,
8. Personal communication with George Flores, Dow Chemical Company, February
. 14, 1984.
A-14
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-------
1. REPORT NO.
EPA-450/4-84-0071
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
4. TITLE AND SUBTITLE
2.
Locating And Estimating Air Emissions From Sources
Of Phosgene
7. AUTHOR(S)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
2. SPONSORING AGENCY NAME AND ADDRESS
Monitoring And Data Analysis Division (MD 14)
Office Of Air Ouality Planning And Standards
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
15. SUPPLEMENTARY NOTES
EPA Project Officer: Thomas F. Lahre
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
September 1985
G. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
VCT
To assist groups interested in inventorying air emissions of various
potentially toxic substances, EPA is preparing a series of documents such as this
to compile available information on sources and emissions of these substances.
This document deals specifically with phosgene. Its intended audience includes
Federal, State and local air pollution personnel and others interested in locating
potential emitters of phosgene in making gross estimates of air emissions therefrom.
This document presents information on 1) the types of sources that may emit
phosgene, 2) process variations and release points that may be expected within
these sources, and 3) available emissions information indicating the potential for
phosgene release into the air from each operation.
7.
KEY'WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Phosgene
Emissions Sources
Locating Air Emission Sources
Toxic Substances
8. DISTRIBUTION STATEMENT
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
b.lDENTIFIERS/OPEM ENDED TERMS
19. SECURITY CLASS (ThisReport)
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c. COSATI Field/Group
21. NO. OF PAGES
60
22. PRICE
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EPA Form 2220-1 (Rev. 4-77) (Reverse)
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