United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/4-84-007k
September 1985
Air
Locating And
Estimating Air
Emissions From
Sources Of
Vinylidene Chloride
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EPA-450/4-84-007k
September 1985
Locating And Estimating Air Emissions
From Sources Of Vinylidene Chloride
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office Of Air And Radiation
Office Of Air Quality Planning And Standards
Research Triangle Park, North Carolina 2771 1
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-450/4-84-007k
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CONTENTS
Figures iv
Tables v
1. Purpose of Document 1
2. Overview of Document Contents 3
3. Background 5
Nature of Pollutant 5
Overview of Production and Uses 7
4. Vinylidene Chloride Emission Sources 10
Vinylidene Chloride Production 10
Perchloroethylene and Trichloroethylene
Production 19
1,1,1-Trichloroethane Production. . 28
Polymerization of Vinylidene Chloride . . 33
Use of Vinylidene Chloride in Specialty
Chemical Production. .... 44
Vinylidene Chloride Copolymer Fabrication 45
Volatilization From Waste Treatment, Storage and
Disposal 53
5. Source Test Procedures 55
References 58
Appendix - Fugitive Emission Calculations for Vinylidene
Chloride Production From 1,1,2-Trichloroethane A-l
References for Appendix A-8
ill
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FIGURES
Number Page
1 Chemical use tree for vinylidene chloride 8
2 Basic operations that may be used for vinylidene
chloride production fron 1,1, 2-trichloroethane 12
3 Basic operations that may be used in perchloro-
ethylene and trichloroethylene production by
chlorination of ethylene dichloride 20
4 Basic operations that may be used in perchloroethylene
and trichloroethylene production by oxychlorination
of ethylene dichloride 23
5 Basic operations that may be used in the production
of 1,1,1-trichloroethane from ethane 30
6 Basic reactions involved in the polymerization of
vinylidene chloride with a comonomer 34
7 Basic operations that may be used for the production
of vinylidene chloride copolymers .37
8 Basic operations that may be used in the coating of
cellophane with high-VBC copolymer 46
9 Method 23 sampling train 56
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TABLES
Number Page
1 Physical and Chemical Properties of Vinylidene
Chloride 6
2 Estimated Controlled and Uncontrolled Vinylidene Chloride
Emission Factors for a Hypothetical Vinylidene
Chloride Production Facility 14
3 Producers of Vinylidene Chloride 18
4 Estimated Controlled and Uncontrolled Vinylidene Chloride
Emission Factors for Hypothetical Perchloroethylene/
Trichloroethylene Production Processes 25
5 Facilities Producing Perchloroethylene and/or
Trichloroethylene 27
6 Facilities Producing 1,1,1-Trichloroethane 32
7 Vinylidene Chloride Copolymers, Production Methods,
and Applications 36
8 Estimated Controlled Vinylidene Chloride Emission Factors
for a Hypothetical Vinylidene Chloride Polymerization
Plant 40
9 Potential Emission Controls for Polymer Plants 42
10 Facilities Producing Polyvinylidene Chloride 43
11 Estimates of Uncontrolled Emission Factors from
High-VDC Copolymer Fabrication Processes 49
12 Facilities Fabricating High Vinylidene Chloride
Copolymers 51
A-l Estimated Process Line Composition in VDC Production. . . . A-3
A-2 Estimated VDC Emissions from Valves and Pumps A-5
A-3 Estimated VDC Emissions from Relief Valves A-6
A-4 Fugitive Emission Controls and Estimated Controlled
Emission Rates A-7
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SECTION 1
PURPOSE OF DOCUMENT
EPA, States and local air pollution control agencies are beconing
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 regulate 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 potentially toxic substances, EPA is preparing a series of
documents such as this that compiles available information on sources
and emissions of these substances. This document specifically deals
with vinylidene chloride. Its intended audience includes Federal, State
and local air pollution personnel and others who are interested in
locating potential emitters of vinylidene chloride and making
preliminary estimates of air emissions therefrom.
Because of the limited amounts of data available on vinylidene
chloride emissions, and since 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 pollution personnel about 1) the types of sources
that may emit vinylidene chloride, 2) process variations and release
points that may be expected within these sources, and 3) available
emissions information indicating the potential for vinylidene chloride
to be released into the air from each operation.
The reader is strongly cautioned against using the emissions
information contained in this document to try to develop an exact
assessment of emissions from any particular facility. Since
insufficient data are available to develop statistical estimates of the
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accuracy of these emission factors, 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 extreme cases, that
orders-of-magnitude differences could result between actual and
calculated emissions, depending on differences in source configurations,
control equipment and operating practices. Thus, in situations where an
accurate assessment of vinylidene chloride emissions is necessary,
source-specific information should be obtained to confirm the existence
of particular 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 is to assist
Federal, State and local air pollution control agencies and others who
are interested in locating potential air emitters of vinylidene chloride
and making preliminary 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 provides a brief summary of the physical and chemical
characteristics of vinylidene chloride, its commonly occurring forms and
an overview of its production and uses. A chemical use tree summarizes
the quantities of vinylidene chloride consumed in various end use cate-
gories in the United States. This background section may be useful to
someone who needs to develop a general perspective on the nature of the
substance and where it is manufactured and consumed.
Section A focuses on major industrial source categories that may
emit vinylidene chloride to the air. This section discusses the pro-
duction of vinylidene chloride, its use as an industrial feedstock, and
processes which produce vinylidene chloride as a byproduct. For each
major industrial source category described in Section 4, example process
descriptions and flow diagrams are given, potential emission points are
identified, and available emission factor estimates are presented that
show the potential for vinylidene chloride emissions before and after
controls employed by industry. Using trade publications and other
sources, individual companies are identified that are reported to be
involved with either the production or use of vinylidene chloride.
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The final section of this document summarizes available procedures
for source sampling and analysis of vinylidene chloride. Details are
not prescribed nor is any EPA endorsement given or implied to any of
these sampling and analysis procedures. At this time, EPA generally has
not evaluated these methods. Consequently, this document merely
provides an overview of applicable source sampling procedures, citing
references for those interested in conducting source tests.
This document does not contain any discussion of health or other
environmental effects of vinylidene chloride, nor does it include any
discussion of ambient air levels or ambient air monitoring techniques.
Comments on the contents or usefulness of this document are
welcomed, as is any information on process descriptions, operating
practices, control measures and emissions 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, N.C. 27711
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SECTION 3
BACKGROUND
NATURE OF POLLUTANT
Vinylidene chloride (VDC) is a clear liquid with low viscosity at
room temperature. It has a sweet odor similar to other chlorinated
hydrocarbons, which can be detected at concentrations of about 500
ppm. The chemical name for vinylidene chloride is 1,1-
dichloroethylene; it is also refered to technically as vinylidene
dichloride. The structure of VDC is illustrated below:
Clx ^
r*=C'
Cl' XH
Vinylidene chloride is practically insoluble in water, but is soluble in
most other polar and nonpolar solvents. It is very soluble in
chloroform and ether, and is soluble in benzene, acetone, and ethanol.
1 9
Chemical and physical properties of VDC are summarized in Table 1. '
In the presence of air or oxygen, vinylidene chloride can form a
peroxide compound that is violently explosive. The peroxide also
initiates polymerization of the bulk VDC. Commercial grades of VDC
typically contain about 200 ppm of hydroquinone monomethyl ether (MEHQ)
inhibitor, which prevents the formation of peroxide and spontaneous
polymerization. Other impurities in commercial grade vinylidene
chloride include trans-l,2-dichloroethylene (900 ppm), vinyl chloride
(850 ppm), 1,1,1-trichloroethane (150 ppm), cis-l,2-dichloroethylene (10
ppm), 1,1-dichloroethane (<10 ppm), ethylene chloride (<10 ppm), and
trichloroethylene (<10 ppm).1'2
Vinylidene chloride liquid is very volatile, with a vapor pressure
of 660 mm Hg at room temperature. Its vapor burns readily when ignited.
The flash point of the liquid is about -15°C, the lower explosive limit
of the vapor in air is 7 percent, and the upper explosive limit is 16
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TABLE 1. PHYSICAL AND CHEMICAL PROPERTIES OF VINYLIDENE CHLORIDE2
Synonyms: VDC, 1,1,-dichloroethy lene, 1,1-dichloroethene, vinylidene
dichloride
Chemical formula C^C = CH£
CAS registry number 75-35-4
Molecular weight, g/mole 96.9
Density (20°C liquid), g/cm 1.2137
Boiling point, °C 31.56
Melting point, °C -122.56
Flash point, °C
open cup -16
closed cup -28
Autoignition temperature in air, °C 513a
Flammable limits in air, volume percent 5.6-16.0
Latent heats, kJ/tnoie
vaporization (at boiling point) 26.48
fusion (at freezing point) 6.51
Heat of combustion (25°C liquid), kJ/mole 1095.9
Heat of polymerization (25°C), kJ/mole -75.3
Heat of formation, kJ/mole
liquid -25.1
vapor 1 . 26
Heat capacity, J/mole-K
liquid 111.27
vapor (25°C) 67.03
Critical properties
Temperature, °C 280.8
Pressure, MPa 5.21
Volume, cm-Vmole 218
Vapor pressure, kPa
0°C 28.92
10°C 44.54
20°C 66.34
. 30°C 95.91
Water solubilities at 20°C, g/lOOg
Vinylidene chloride in water 0.25
Water in vinylidene chloride 0.035
Dielectric constant (16°C liquid) 4.67
Viscosity (20°C), centipoise 0.33
aVDC stabilized by MEHQ .
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percent. The decomposition products of VDC exposed to oxygen include
1 2
formaldehyde, phosgene, and hydrogen chloride. '
The residence time of vinylidene chloride in the atmosphere is
about 23 hours, where residence time is defined as the time required for
the concentration to decay to 1/e (37%) of its original value. The
major mechanism for destruction of VDC in the atmosphere is reaction
with hydroxyl radicals. The principal reaction products are formic
acid, carbon monoxide, chloroacetyl chloride, hydrogen chloride,
phosgene, and formaldehyde. »**
Vinylidene chloride can also be polymerized to produce
polyvinylidene chloride (PVDC) polymer chains made up of monomer units
joined head to tail:
H Cl H Gl H Cl
I I I i I i
~~~ C~~"C~"C"~"C~~~C~C ~
I I I I I I
H Cl H Cl H Cl
Vinylidene chloride can also be polymerized with other monomers to
produce polyvinylidene chloride copolymers.
OVERVIEW OF PRODUCTION AND USES
Vinylidene chloride was first used in the late 1930's by Dow
Chemical Company. VDC is produced commercially by the dehydrochlorina-
tion of 1,1,2-trichloroethane with lime or caustic. It may also be
recovered as a byproduct of chlorination and oxychlorination reactions
to produce other compounds. Today, production of VDC in the United
o
States exceeds 90,700 megagrams (Mg) per year. Exact production
figures are not available because the producers of VDC consider these to
be proprietary.
Figure 1 gives a chemical use tree summarizing the production and
2 ^ S7
use of VDC. ' ' The main use of VDC is in the production of VDC
copolymers. About 68,000 Mg of VDC are consumed annually in the pro-
9
duction of polymers containing VDC. In the United States, the generic
term "Saran" is used to refer to high VDC-content polymers. Saran
formerly was a trademark of the Dow Chemical Company and is still a Dow
trademark in other countries. PVDC homopolymer (Saran A) is difficult
to fabricate and for this reason is not used. However, copolymers of
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Cl
\ /
/ \
1,1,2-trichl
ethane
Cl
\ /
H - C C
/ \
H
athvlene
sichlond
VDC
USES
Cl
H
oro-
Cl x"'
H
H \
e
H Cl
HaOH \ /
Hpi * Nrtfl + C - C »-
2 / \
H C1 VDC
VDC PRODUCTION
Cl Cl Cl Cl
\ / \ / byproducts
s - HC1 * C = C » C = C * including
x"^ 1 \ 1 \ VDC
x^Cl K Cl Cl Cl
2
trichloro- percnloro-
athylene ethyl ens
Cl Ci Cl Cl Cl
^2 \ / \ / byproducts
0 ^ HC1 * C = C « C = C * including '
2 / \ 1 \ VDC
H Cl Cl Cl
Saran films
H Cl High-VDC ^^ Saran coatings
\ / other heat copolynera
/ \ «ono»er initiator Low-VDC
H Cl copolymers ~_^__^ Tlane retardent rug backing
Synthetic fibers
VDC
K Cl 0 Cl Cl Intermediate
\ 1 2 \ / in the
1 C * C » H C C oroduction
/ \ Cl / ^5. of tear gas and
H Cl 2 H 0 Pharmaceuticals
chloroacetyl
chloride
Figure 1. Chemical use tree for vinylidene chloride.2,3,5 7
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vinylidene chloride with vinyl chloride (Saran B), alkyl acrylates
(Saran C), and aerylonitrile (Saran F) are widely used. Polymers con-
taining VDC are resistant to photodegradation and chemical attack, and
because of their high density and crystal linity, they are impermeable to
a wide range of gases. The low permeability of VDC copolymers to water
and oxygen is the main reason for the commercial importance of
7 Q
vinylidene chloride. '
In addition to the production of Saran polymers, VDC is also used as
Q
a chemical intermediate in the production of chloroacetyl chloride.
Chloroacetyl chloride is a chemical intermediate in the production of
pharmaceutical products and tear gas. Formerly, a major use of VDC
(about 60,000 Mg/yr) was as an intermediate in the production of 1,1,1-
trichloroethane. However, the VDC-based process for 1,1,1-
trichloroethane was only used at one plant, and was replaced in the late
1970's by a vinyl chloride based process.
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SECTION 4
VINYLIDENE CHLORIDE EMISSION SOURCES
This section discusses vinylidene chloride emissions from
processes where the chemical is produced, processes where it is used as
a chemical intermediate, and processes where it is produced as a
byproduct. Process and emissions data are presented for each source
category.
The following industrial processes have been identified as
potential sources of VDC emissions:
vinylidene chloride production,
perchloroethylene and trichloroethylene production,
1,1,1-trichloroethane production,
VDC polymerization,
use of VDC in specialty chemical production,
VDC copolymer fabrication, and
volatilization from waste treatment, storage, and disposal.
VDC is a byproduct of perchloroethylene and trichloroethylene production
and of 1,1,1-trichloroethane production from ethane.
VINYLIDENE CHLORIDE PRODUCTION
Vinylidene chloride is produced domestically by the
211
dehydrochlorination of 1,1,2-trichloroethane with sodium hydroxide. »
Three plants in the U.S. produce VDC; each of these produces a number
of other chlorinated hydrocarbons by a variety of processes. The raw
material 1,1,2-trichloroethane is produced as a coproduct in the
chlorination and oxychlorination of ethane, ethylene, and ethylene
dichloride (1,2,-dichloroethane) to produce chlorinated £~ species.
At the plants using the 1,1,2-trichloroethane dehydrochlorination
10
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process, additional VDC may also be recovered as a byproduct of various
chlorination and oxychlorination processes. These processes are
discussed in later sections.
Process Description
The reaction for the dehydrochlorination of 1,1,2-
trichloroethane to produce VDC is as follows:
H Cl H Cl
* / \ /
Cl-C-C-H -i- NaOH »- C = C + NaCl + HoO
/ \ / \ ^
H Cl H Cl
1,1,2-tri sodium VDC
chloroethane hydroxide
The reaction is carried out with 2 to 10 percent excess caustic and
product yields ranging from 85 to 90 percent. Basic operations that
may be used in the production of VDC from 1,1,2-trichloroethane are
chown in Figure 2. Concentrated sodium hydroxide (Stream 1) is diluted
with water (Stream 2) to about 5 to 10 weight percent and is mixed with
the 1,1,2-trichloroethane feed (Stream 3) and fed (Stream 4) to the
dehydrochlorination reactor. The reaction is carried out in the liquid
phase at about 100°C without catalyst. Because the aqueous and organic
reactants are not miscible, the reaction is carried out in a liquid
dispersion. The dehydrochlorination reactor is continuously purged with
nitrogen (Stream 5) to prevent the accumulation of monochloroacetylene
impurity in the product VDC. The nitrogen is discharged from Vent A.
The VDC-containing product from the dehydrochlorination reactor
(Stream 6) is separated in a decanter into an aqueous phase (Stream 7)
and an organic phase (Stream 8). The aqueous phase, comprising a sodium
hydroxide/sodium chloride solution, is divided. One fraction
(Stream 9) is recycled (Stream 4) to the hydrochlorination reactor, and
the other fraction (Stream 10) is steam stripped to remove organics
and discharged to a wastewater treatment system (Discharge F).
The organics from the aqueous phase (Stream 11) are combined with
the organic phase from the decanter (Stream 8). The combined organics
(Stream 12) are fed to a drying column, where residual water is removed
as a bottoms stream (Stream 13). The water removed from the drying
11
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column is fed to the steam stripper with the aqueous stream from the
product decanter (Stream 10).**
The organic stream from the drying column (Stream 14) is fed to a
distillation column, which removes unreacted 1,1,2-trichloroethane as
overheads (Stream 15). The unreacted trichloroethane is recycled to the
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pressurized tanks before being shipped to users.
Emissions
Uncontrolled VDC emission factors for VDC production are given in
Table 2. The table also lists potentially applicable control techniques
and associated controlled emission factors. The emission factors were
developed based on published data for individual plants and for general
processing techniques. Because of variation in process design, age of
equipment, and other process parameters, actual emissions vary for each
plant.
Process Vent Emissions
Process vents which are sources of VDC emissions include the
reactor nitrogen purge vent (Vent A, Figure 2) and the distillation
column vents (Vents B, Figure 2). Uncontrolled VDC emission factors are
estimated at 6.2 kilograms VDC per megagram VDC produced (kg/Mg) for the
13
reactor vent, and 0.7 kg/Mg for the distillation vents.
Emissions from the reactor vent can be controlled by incineration
with an efficiency of about 98 percent or higher. '' The major
products of VDC incineration are CO- and HC1. However, under poor
incinerator operating conditions, other products may be formed, in-
cluding formic acid, carbon monoxide, chloroacetyl chloride, phosgene,
and formaldehyde. Incineration destruction efficiency varies with emis-
sion stream properties and incinerator operating parameters. The 98
percent efficiency level is a conservative estimate of the control that
may be expected at a temperature of at least 870°C and a residence time
of at least 0.75 seconds. 5t The emission reduction may be greater
than 98 percent for incineration of VDC with these operating parameters,
13
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and would also increase at higher temperatures and longer residence
times. A 98 percent reduction of reactor vent emissions corresponds
to a controlled VDC factor of about 0.12 kg/ Mg VDC produced. Con-
trolled reactor vent emissions reported for specific plants range from
0.063 kg/Mg to 0.090 kg/Mg.16
VDC emissions from the distillation column vents can be controlled
either by aqueous scrubbing or by refrigerated vent condensers with an
efficiency of about 90 percent. > The distillation column vents can
also be combined with reactor emissions and controlled by incineration
with a 98 percent or greater control efficiency. ' The control
efficiency attainable using these techniques is dependent on operating
parameters and emission stream characteristics. A 90 percent reduction
of distillation column vent emissions corresponds to a controlled emis-
sion factor of about 0.07 kg/Mg VDC produced. Controlled VDC emissions
reported for distillation vents at specific plants range fron 0.18 kg/Mg
to 0.38 kg/Mg.16
Storage and Handling Emissions
Vinylidene chloride emissions result from the storage of VDC
product and intermediates containing VDC (Source D, Figure 2).
VDC emissions also occur where VDC product is loaded to tank cars of
trucks. Insufficient data were available to estimate uncontrolled
emissions of VDC from storage and handling. Controlled storage and
handling emissions of VDC reported for two specific facilities were
about 0.056 kg/Mg VDC produced. The types of controls used to attain
this emission rate are not known. Controls typically used to reduce
storage and handling emissions include pressurized storage tanks and
refrigerated vapor condensers.
Process Fugitive Emissions
Fugitive emissions of VDC, 1,1,2-trichloroethane, and other
volatile organic compounds result from leaks in process valves, pumps,
compressors, and pressure relief valves (Source D, Figure 2). Fugitive
emissions from a typical VDC plant were estimated based on process flow
diagrams, process operation data, and emission factors developed by EPA
15
-------
for typical process emission sources. The techniques used to estimate
the numbers of various fugitive emission sources and the total fugitive
emission rate are described in detail in the Appendix.
The estimated uncontrolled fugitive emission rate for VDC
production from 1,1,2-trichloroethane is about 0.96 kg VDC/hr. Fugitive
emission rates differ from plant to plant depending on the number of
valves, pumps, flanges, etc., the age of the equipment, and the level of
emission control used. Chemical process streams in the production of
chlorinated hydrocarbons such as VDC generally contain chlorine and HC1,
as well as hydrocarbons. These compounds are extremely corrosive and
irritating when exposed to the moisture in ambient air. Thus, it is
general practice to control such fugitive emissions in order to prevent
1 R
corrosion of outside equipment and generation of unpleasant odors.
Table 2 gives control efficiencies for preventative maintenance
programs, the use of double mechanical seals of pumps, and the use of
rupture disks with relief valves. Other controls which nay be used
include the use of welded pipe in place of flanges, special construction
materials for piping and valves, enclosure of pumps, and intensive
preventative maintenance during plant shutdown. In addition, inspection
and maintenance programs practiced at some plants may be much more
intensive than those shown on Table 2, such that most leaks are repaired
within as little as 1 day. With these additional controls, industry
reports fugitive emission control efficiencies as high as 90 to 95
percent.18'19
Secondary Emissions
Secondary emissions result from the handling and disposal of
process waste streams. In VDC production from 1,1,2-trichloroethane,
wastewater from the VDC production reaction (Source F, Figure 2) is a
potential source of secondary VDC emissions. Specific data were not
available to estimate emissions from the treatment and disposal of this
stream. Figure 2 shows that a wastewater stripper typically is
incorporated as part of the VDC production process to reduce
VDC emissions and for product recovery.11 Emissions from treatment of
16
-------
contaminated wastewater are discussed in further detail in the section
entitled VOLATILIZATION FROM WASTE TREATMENT, STORAGE, AND DISPOSAL.
Source Locations
Major vinylidene chloride producers and production locations are
listed in Table 3.20
17
-------
TABLE 3. PRODUCERS OF VINYLIDENE CHLORIDE20
Manufacturer Location
Dow Chemical U.S.A. Freeport, TX
Plaquemine, LA
PPG Industries, Inc.
Chemicals Group
Chemical Division Lake Charles, LA
Note: This listing is subject to change as market conditions change,
facility ownership changes, plants are closed, etc. The reader
should verify the existence of particular facilities by consult-
ing current listings and/or the plants themselves. The level of
VDC emissions from any given facility is a function of variables
such as capacity, throughput and control measures, and should be
determined through direct contacts with plant personnel.
18
-------
PERCHLOROETHYLENE AND TRICHLOROETHYLENE PRODUCTION
Perchloroethylene (PCE) and trichloroethylene (TCE) are produced
separately or as coproducts by either chlorination or oxychlorination of
ethylene dichloride (EDC) or other G£ chlorinated hydrocarbons. A
number of byproducts are produced in each of these reactions, including
vinylidene chloride (VDC). These byproducts may be isolated and
refined, recycled to the process, or dischaged in various waste streams.
For instance, in a case whete VDC is produced from 1,1,2-trichloroethane
at a facility which also produces TCE and PCE, the VDC byproduct may be
recovered and purified by distillation in the VDC finishing section of
i ^
the 1,1,2-trichloroethane process. ^ Raw material ratios and reactor
conditions determine the relative proportions of PCE, TCE, and any
byproducts produced.
Process Descriptions
Ethylene Dichloride Chlorination Process
The overall reactions for the chlorination of EDC to produce TCE
and PCE, are as follows:
Cl Cl Cl Cl
\ / ^ /
H-C-C-H -t- 3C12 heat*- C = C + 4HC1 + byproducts
H H Cl Cl
EDC PCE
Cl Cl Cl Cl
,<.».
H-C-C-H + 2C1, ££££ »- C = C + 3HC1 + byproducts
/ \ L I \
H H Cl H
EDC TCE
VDC is among the byproducts produced in these reactions. Basic
operations that may be used in the EDC chlorination process are shown in
Figure 3.21
Ethylene dichloride (Stream 1) and chlorine (Stream 2) are
vaporized and fed to the reactor. Other chlorinated £<^ hydrocarbons or
recycled chlorinated hydrocarbon byproducts may also be fed to the
19
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20
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reactor. In the reactor, a chlorination reaction is carried out at 400°
to 450°C, slightly above atmospheric pressure. The reaction produces
the desired products TCE and PCE, as well as byproducts, including
vinylidene chloride and hydrogen chloride. Hydrogen chloride byproduct
(Stream 3) is removed as an overhead stream from the chlorinated
hydrocarbon mixture (Stream 4) produced in the reactor. The chlorinated
hydrocarbon mixture (Stream 4) is neutralized with sodium hydroxide
7 i
solution (Stream 5) and dried.
The dried crude product (Stream 7) is separated by a distillation
column into crude TCE (Stream 8) and crude PCE (Stream 9). The crude
TCE (Stream 8) is fed to two columns in series which remove light ends
(Stream 10) and heavy ends (Stream 13). TCE (Stream 12) is taken
overhead from the heavy ends column and sent to TCE storage; the heavy
ends (Stream 13) and the light ends (Stream 10) are combined, stored,
7 1
and recycled. l
The crude (Stream 9) from the PCE/TCE separation column is sent to
the PCE column, where PCE (Stream 14) is removed as an overhead stream
to PCE storage. Bottoms from this column (Stream 15) are sent to a
heavy ends column and separated into heavy ends and tars. Heavy ends
rj I
(Stream 16) are stored and recycled, and tars are incinerated. *
Ethylene Bichloride Oxychlorination Process
The overall reactions for the production of perch loroethy lene and
tr ichloroethylene by EDC oxy chlorination are as follows:
Cl Cl Cl Cl
\ / CuCl- \ /
H-C-C-H + C10 + 0~ - £-»- C = C + 2H-0 + byproducts
/ \ L 2. , \ /
H H Cl Cl
Cl Cl Cl Cl
\ / CuCl- \ /
H-C-C-H + 1/2 C10 + 1/4 00 - * + C = C + 3/2 H.,0 + byproducts
/ \ L L I \ L
H H Cl H
The crude product contains 85 to 90 weight percent PCE plus TCE,
and 10 to 15 weight percent byproduct organics, including VDC. Essen-
tially all byproduct organics are recovered during purification and are
21
-------
recycled to the reactor. The process is very flexible, so that the
reaction can be directed toward the production of either PCS or TCE in
varying proportions. Side reactions produce carbon dioxide, hydrogen
chloride, and several chlorinated hydrocarbons. Figure 4 shows basic
operations that may be used in oxychlorination. u
Ethylene dichloride (Stream 1), chlorine or hydrogen chloride
(Stream 2), and oxygen (Stream 3) are fed in the gas phase to a fluid
bed reactor. The reactor contains a vertical bundle of tubes with
boiling liquid outside the tubes which maintains the reaction tempera-
ture at about 425°C. The reactor is operated at a pressure slightly
above atmospheric, and the catalyst, which contains copper chloride, is
21
continuously added to the tube bundle with the crude product.
The reactor product stream (Stream 4) contains the desired products
TCE and PCE, as well as byproducts including VDC. This stream is fed
serially to a water cooled condenser, a refrigerated condenser, and a
decanter. The noncondensed inert gases (Stream 5), consisting of carbon
dioxide, hydrogen chloride, nitrogen, and a small amount of uncondensed
chlorinated hydrocarbons, are fed to an absorber, where hydrogen
chloride is recovered by absorption in process water to make byproduct
hydrochloric acid (Stream 6). The remaining inert gases are purged
(Vent A). 21
In the decanter, the crude product (Stream 7) is separated from the
aqueous phase and catalyst fines (Stream 8) and sent to the drying
column for removal of dissolved water by azeotropic distillation. The
dried crude product (Stream 10) is separated into crude TCE (Stream 11)
and crude PCE (Stream 12) in a PCE/TCE column. The aqueous phase from
the decanter (Stream 8) and the water from the drying column (Stream 9)
21
are sent to waste treatment.
The crude TCE (Stream 11) is sent to the TCE column, where light
ends (Stream 13) are removed to be stored and recycled. The bottoms
(Stream 14), containing mainly TCE, are neutralized with ammonia and
then dried to produce finished TCE (Stream 15) which is sent to the TCE
71
storage.
The crude PCE (Stream 12) from the PCE/TCE separation column is fed
to a heavy ends removal column where PCE and light ends (Stream 16) go
22
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overhead to a PCE finishing column, and the heavy ends (Stream 17)
remaining as the bottoms are sent to the organic recycle system. Here,
the organics that can be recycled (Stream 18) are separated from tars
and sent to the recycle organic storage. The tars are incinerated. The
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(Stream 22) which is sent to PCE storage.21
Emissions
Process Vent Emissions
Table 4 gives emissions data for process vents in PCE and TCE
production processes which may contain VDC. The table lists:
uncontrolled VDC emission factors, potentially applicable control
9 9
techniques, and associated controlled VDC emission factors. These
emissions data were developed based on published information for general
operations used in the production of PCE and TCE. Variations in process
design, feed materials, and reaction conditions have a substantial
effect on amounts of VDC and other byproducts produced by PCE and TCE
production processes. As a result, VDC emissions vary for each plant.
Chlorination process- Vents containing VDC in the EDC chlorination
process include the neutralization and drying vent (Vent A, Figure 3),
and distillation column vents (Vents B, Figure 3). Uncontrolled VDC
emission factors are estimated at 2.5 kilograms per megagram PCE and
TCE produced (kg/Mg), for the neutralization and drying vent, and 0.106
kg/Mg PCE and TCE, for the distillation vent.
Emissions from both of these sources can be controlled by
refrigerated vapor condensers with an efficiency of about 80 percent.
The control efficiency attainable using refrigeration is dependent on
emission stream characteristics and condenser operating temperatures.
Oxychlorination process - Vent streams containing VDC in the EDC
oxychlorination process include the reactor vent (Vent A, Figure 4), the
drying column vent (Vent B, Figure 4) and the distillation column vents
24
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(Vent C, Figure 4). Uncontrolled VDC emission factors have been
estimated at 0.4 kg/Mg PCE and TCE produced, for the drying column vent,
and 0.098 kg/Mg PCE and TCE, for the distillation column vent.22
The uncontrolled emission rate given in Table 4 for the reactor
vent was calculated based on a total chlorinated hydrocarbon emission
factor for the reactor vent of 21.3 kg chlorinated hydrocarbon emitted
per megagram PCE and TCE produced.22 It was assumed that the fraction
of the total chlorinated hydrocarbons comprised by VDC in the reactor
vent is the same as the fraction of chlorinated hydrocarbons comprised
by VDC in the drying column vent. In the drying column vent, VDC
7 7
comprises about 18 percent of total chlorinated hydrocabon emissions.
Thus, VDC emissions from the reactor vent were estimated as follows:
(21.3 kg Cl species/Mg) x (0.18 kg VDC/kg Cl species) = 3.8 kg VDC/Mg
Emissions from the reactor and drying column vents can be
controlled by incineration with an efficiency of about 98 percent or
higher. '^ Emissions from the distillation column vent can be
controlled by aqueous scrubbing with an efficiency of about 90
14
percent.
Other Emission Sources
In addition to process vents, potential VDC emission sources from
PCE and TCE production include storage and handling operations, process
fugitive sources, and treatment and disposal of process wastes. VDC is
expected to be emitted from recycle storage tanks in both the
chlorination and oxychlorination processes for PCE and TCE production
(Vent C in Figure 3, and Vent D in Figure 4). VDC is also emitted from
any pumps, compressors, flanges, and valves which are exposed to streams
containing VDC (Source E in Figure 3 and Source I in Figure 4).
Insufficient information is available to estimate VDC emissions from
these sources,
Source Locations
Major producers of perchloroethylene and/or trichloroethylene are
listed in Table 5.20
26
-------
TABLE 5. FACILITIES PRODUCING PERCHLOROETHYLENE
AND/OR TRICHLOROETHYLENE20
Company
Location
Chemical
produced
PCEa
TCEb
Diamond Shamrock Corp.
Dow Chemical U.S.A.
E.I. duPont de Nemours
and Co.
PPG Industries, Inc.
Stauffer Chemical Co.
Vulcan Materials Co.
Deer Park, TX
Freeport, TX
Pittsburg, CA
Plaquemine, LA
Corpus Christi, TX
Lake Charles, LA
Louisville, KYC
Geismar, LA
Wichita, KS
X
X
X
X
X
X
X
X
aPCE = perchloroethylene
bTCE = trichloroethylene
cPlant has been on standby since 1981.
Note: This is a list of major facilities producing perchloroethy lene
and/or trichloroethylene by any production process. Current
information on which of these facilities produce these chemicals
by ethylene dichloride chlorination or oxychlorination is not
available. This list is subject to change as market conditions
change, facility ownership changes, or plants are closed down.
The reader should verify the existence of particular facilities
by consulting current listings or the plants themselves. The
level of emissions from any given facility is a function of
variables, such as operating conditions, product slate,
throughput and control measures, and should be determined through
direct contacts with plant personnel. Under some operating
conditions, byproduct VDC production may be negligible, resulting
in negligible or zero VDC emissions. For instance, Dow chemical
has indicated that VDC byproduct is only produced in trace
quantities at all of its three plants. *
27
-------
1, 1, 1-TRICHLOROETHANE PRODUCTION
Most 1,1, 1-trichloroethane produced in the U.S. is made from vinyl
chloride. An ethane-based process currently is used to a lesser extent.
Also, a process starting from VDC formerly was used to produce 1,1,1-
trichloroethane. » This section discusses VDC emissions from the
ethane process, which produces VDC as a byproduct. VDC is not produced
as a byproduct of the vinyl chloride process.
Process Description
In the ethane process for 1,1, 1-trichloroethane production, ethane
is chlorinated to produce the product 1,1, 1-trichloroethane and a number
of byproducts. The main reactions in the chlorination process are as
follows:
CH3-CH3 + Cl2-^*-CH3-CH2Cl + HC1
ethane ethyl chloride hyrodgen chloride
CH3-CH2C1
CH3-CHC12
+ HC1
1 , 1-dichloroe thane
H2=CH2 + HC1
ethy lene
l2-^-*-CH3-CCl3 + HC1
1, 1, 1-trichloroethane
HC1
vinyl chloride
-A^ CH2=CC12 + HC1
vinylidene chloride
Minor quantities of 1, 2-dichloroethane and 1,1, 2-trichloroethane are
also produced. Raw material ratios and reactor conditions determine the
relative proportions of 1,1, 1-trichloroethane and byproducts produced.
If 1,1, 1-trichloroethane is the only product desired, ethyl chloride and
1,1-dichloroethane can be recycled to the chlorination reactor, and
vinyl chloride and VDC can be catalytical ly hydrochlorinated to yield
1,1-dichloroethane and 1, 1, 1-trichloroethane, respectively:
28
-------
CH2=CHC1 + HC1 - *-CH3-CHCl2
FeCl-
CHo=CClo + HC1
4m *-
Basic operations which may be used in the ethane process for 1,1,1-
7 *}
trichloroethane are shown in Figure 5. In this process, byproduct
chlorinated species, including VDC, are recycled and converted to 1, 1,1-
trichloroethane. Chlorine (Stream 1) and ethane (Stream 2) are fed to
the chlorination reactor along with recycle streams of 1,1-
dichloroethane (Stream 13) and ethyl chloride (Stream 17). The reactor
is adiabatic, with a residence time of about 15 seconds, and is
maintained at a pressure of about 600 kiloPascals (5.9 atmospheres) and
an average temperature of about 400°C. No catalyst is used.
The reactor exit stream (Stream 3) is a gas containing ethane,
ethylene, vinyl chloride, ethyl chloride, VDC, 1, 1-dichloroethane,
1, 2-dichloroethane, 1, 1,2-trichloroethane, 1, 1,1-trichloroethane, hydro-
gen chloride, and minor amounts of other chlorinated hydrocarbons. This
stream enters a quench column, where it is cooled, and a residue com-
prising mainly tetrachloroethanes and hexachloroethane is removed
(Stream 4).
The overhead stream from the quench column (Stream 5) is fed to a
hydrogen chloride column, in which ethane, ethylene, and HC1 are removed
from chlorinated hydrocarbons. A portion of the overheads (Stream 6)
containing HC1 is used to provide the HC1 requirements for VDC and vinyl
chloride hydrochlorination in a later step. The remainder (Stream 7) is
purified for use in other processes.
The bottoms from the HC1 column (Stream 8), containing chlorinated
hydrocarbons, are fed to a heavy ends column, where a bottoms stream
(Stream 9), comprising mainly 1, 2-dichloroethane and 1, 1,2-
trichloroethane, is removed for use in other processes. Overheads from
the heavy ends column (Stream 10), containing 1, 1,1-trichloroethane,
vinyl chloride, VDC, ethyl chloride and 1, 1-dichloroethane, are fed to
the 1, 1,1-trichloroethane column, which removes the product as a bottoms
stream (Stream 11).
29
-------
a
3
-a
o
a.
QJ
-------
Overheads from the product recovery column (Stream 12) are fed to
another column, where 1,1-dichloroethane is removed as bottoms
(Stream 13) and recycled to the chlorination reactor. Overheads from.
this column (Stream 14), containing mainly vinyl chloride, VDC and ethyl
chloride, are fed along with the HC1 byproduct stream (Stream 6) to a
hydrochlorination reactor. This reactor operates at a temperature of
about 65°F, a pressure of about 450 kPa, and with ferric chloride
catalyst. Alternatively, these byproducts may be used in other
processes at the plant.
The hydrochlorination reactor converts vinyl chloride and VDC to
1,1-dichloroethane, and 1,1,1-trichloroethane, respectively. Thus, the
reactor product stream (Stream 15) consists of unreacted ethyl chloride
and 1,1-dichloroethane and 1,1,1-trichloroethane. This product stream
is mixed with ammonia to neutralize residual HC1 and catalyst. Spent
neutralized catalyst is removed in a filter and the product is then fed
to a product recovery column. The bottoms from this column (Stream 16),
mostly 1,1,1-trichloroethane, are recycled to the 1,1,1-trichloroethane
column. Overheads (Stream 17), composed of ethyl chloride and 1,1-
2"3
dichloroethane, are recycled to the chlorination reactor,
Emissions
Potential VDC emission sources from the ethane process for 1,1,1-
trichloroethane include (1) the vents for the 1,1,1-trichloroethane and
1,1-dichloroethane distillation columns (Source A) and (2) process fugi-
tive sources, such as valves, flanges, pumps, relief valves, and drains,
located between the chlorination reactor and the hydrochlorination
reactor. Data from one plant indicate that the concentration of VDC in
n *
the distillation column vents is negligible. Data are not available
to estimate fugitive emissions of VDC from the ethane process.
Source Locations
Major producers of 1,1,1-trichloroethane are listed in
Table 6. 5^0 Information is not available on which of these plants use
the vinyl chloride process and which use the ethane process.
31
-------
TABLE 6. FACILITIES PRODUCING 1,1,1-TRICHLOROETHANElO,20
Company Location
Dow Chemical U.S.A. Freeport, TX
PPG Industries, Inc. Lake Charles, LA
Vulcan Chemicals Geismar, LA
Note: This is a list of major facilities producing 1,1,1-
trichloroethane by any production process. Current information
on which of these facilities produce this chemical from ethane or
vinyl chloride is not available. This list is subject to change
as market conditions change, facility ownership changes, or
plants are closed down. The reader should verify the existence
of particular facilities by consulting current listings or the
plants themselves. The level of emissions from any given
facility is a function of variables, such as throughput and
control measures, and should be determined through direct
contacts with plant personnel.
32
-------
POLYMERIZATION OF VINYLIDENE CHLORIDE
Vinylidene chloride monomer is polymerized with a variety of other
monomers to produce copolymers with special properties. VDC copolymers
can be divided into high VDC polymers, generally containing 70 to 95
percent VDC, and low VDC polymers, generally containing 10 to 70 percent
VDC.
High VDC polymers are unique in their low permeabilities to oxygen,
water vapor, and other gases. They also have good clarity and a glossy
appearance. High VDC polymers typical ly are used as vapor barrier
coatings on various film substrates, such as paper, polyester,
polypropylene, or polyethylene. High VDC polymers are also used to make
Saran films which can be used alone or laminated to other plastic films.
The comonomers most commonly used to produce high VDC polymers are vinyl
9 O C O£
chloride, acrylic acid, acrylic esters and aerylonitrile. ' '
In low VDC polymers, the VDC monomer generally is added to improve
the flame retardant properties of the finished polymer. Low VDC
polymers are used as flame resistant coatings, saturants, dipping
compounds, and adhesives. They can also be sprayed onto fibers and
textiles. Typical comonomers used in these applications include acrylic
esters, vinyl acetate, and vinyl chloride. VDC is used with styrene and
butadiene monomers to produce a flame retardant styrene-butadiene latex
for carpet backing. VDC is also used with aery lonitrile to produce
o o c o A
modacrylic synthetic fibers. ''
Emissions from VDC polymerization are discussed in this section.
Emissions of residual VDC monomer from the subsequent processing and
fabrication of VDC in polymers are discussed in a later section.
Copolymer production and fabrication generally are carried out at
separate facilities.
Process Description
The reactions involved in the production of vinylidene chloride
copolymers are illustrated in Figure 6. The major process used to
produce VDC copolymers is emulsion polymerization. This polymerization
25
technique can be used to produce both latex resin and dried resins.
33
-------
JO - C - C-
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Suspension polymerization is also used to produce dried resins, and
solution polymerization is used to produce copolymers for synthetic
fiber production. 5,26 Table 7 summarizes the types of VDC copolymers
produced and identifies production processes, typical comonomers used,
VDC contents, and major applications for each resin type. 5,26
Emulsion Polymerization
Basic operations which may be used in emulsion and suspension
polymerization of VDC copolymers are shown in Figure 7. '^ VDC monomer
(Stream 1), comonomer (Stream 2), and water (Stream 3) are metered and
charged to a batch reactor along with surfactants and initiator
(Stream 4). The batch is agitated, resulting in the formation of an
emulsion of aqueous and organic phases. After charging, the batch is
heated, causing the activation of the initiator. Initiators generally
used in emulsion polymerization are water soluble peroxides which
dissociate to form free radicals when heated. The initiator radicals,
on contacting the organic monomer phase, initiate the polymerization of
VDC and the comonomer. The polymerization reaction is exothermic;
therefore, after the reaction has commenced, the reactor must be cooled.
In emulsion polymerization, the reactor temperature typically is held at
about 30°C and the reaction duration is about 7 to 8 hours. Additional
monomer and initiator may be fed to the reactor during the course of the
2 25
reaction. The degree of completion is 95 to 98 percent. '
Generally, the polymerized batch (Stream 5) is stripped of
unreacted monomers (Stream 6) using steam and vacuum. This can be done
either in the reactor itself or in a separate stripping vessel. The
unreacted monomer is recycled if possible (Stream 7). For some types of
copolymers, contamination of VDC with other comonomers precludes the
recycle of VDC. Stripped polymer (Stream 8) is transferred to a holding
tank, where it may be mixed with other polymer batches to ensure product
76
uniformity.
Emulsion polymerization can be used to produce either a latex
(Stream 9) or a dry product (Stream 10). A latex is an emulsion of
polymer particles in water, which is sold or used undried. If a dried.
product is desired, water is removed by coagulation and dewatering,
35
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followed by drying with hot air. The dried product comprises polymer
particles. The particle diameter produced by emulsion polymerization is
100 to 150 nanometers. »^S
Suspension Polymerization
The same basic steps are used in suspension polymerization as in
emulsion polymerization (Figure 7). VDC (Stream 1), comonomer
(Stream 2), and water (Stream 3) are metered and charged to a batch
reactor along with surfactant and initiator (Stream 4). In suspension
polymerization, the initiator used is soluble in the organic phase. The
batch is agitated to produce a suspension of the organic phase in the
water phase. After charging, the batch is heated to activate the
initiator, which causes polymerization. The reactor must then be cooled
o o c
to remove the heat of polymerization. »ij
Suspension polymerization generally is carried out at about 60°C.
The duration of the reaction is 30 to 60 hours and the degree of
r\
completion is about 85 to 90 percent. After the polymerization
reaction has reached the desired degree of completion, the polymer
(Stream 5) generally is stripped of unreacted monomer (Stream 6) by
steam and heat, either in the reactor or in a separate vessel.
Unreacted monomer is recycled (Stream 7) or vented to a control system.
The batch is then transferred to a holding tank (Stream 8) and dried
(Stream 11) with hot air to produce dry polymer particles. Typical
particle diameters produced by suspension polymerization range from 150
to 590 microns.2'25
Solution Polymerization
As noted above, solution polymerization is used on the production
of vinylidene chloride copolymer synthetic fibers. These fibers
7 O C O£
typically have a low VDC content. '' Information is not available
on the specific steps used in the solution polymerization of VDC
copolymers; however, the general reaction steps are expected to be
similar to those used in the solution polymerization of other resins.
In a solution polymerization process, the polymerization reaction
is carried out in a solvent which dissolves both the monomers and the
38
-------
finished polymer. Monomers, initiators, and solvents are charged to a
polymerization reactor where the reaction typically is carried out under
elevated temperature and pressure. The process can be carried out
either in a batch process or a continuous process. In either case, the
product is a homogeneous mixture of solvent, polymer, and unreacted
monomers. Unreacted monomer may be stripped from the polymer/solvent
mixture by che use of steam and heat. In a batch process, the stripping
step may be carried out either in the reaction vessel or in a separate
stripping vessel. In a continuous process, a separate stripping vessel
is required.27'28
The resulting polymer solution is used in a "spinning" process to
produce the product synthetic fiber. In this step, polymer fibers are
extruded into a zone of hot vapor or water, where the fibers are
solidified and solvent and residual monomer are removed. This step is
discussed in the subsequent section on the fabrication of VDC copolyiaer
products.26'27'28
Emissions
Potential VDC emissions sources at VDC polymerization plants
include:
VDC unloading and storage;
opening and cleaning of mixing, weighing, holding, and
reaction vessels;
relief valve discharges;
stripper and monomer recovery system vents;
evaporation of residual VDC from the finished copolymer; and
process fugitive sources, including valves, flanges, pumps,
compressors, relief valves, and process drains.
Data are not available to estimate uncontrolled VDC emissions from
these sources. However, in response to previous EPA surveys, several
polymerization plants have reported total controlled emissions of
vinylidene chloride and controlled emissions from a number of individual
1 ft 7 S
sources. ' Controlled VDC emission rates reported for VDC
polymerization are given in Table 8.
Emission factors given in Table 8 for reactor emissions, monomer
recovery emissions, storage and transportation emissions, and total
39
-------
TABLE 8. ESTIMATED CONTROLLED VINYLIDENE CHLORIDE EMISSION FACTORS
FOR A HYPOTHETICAL VINYLIDENE CHLORIDE POLYMERIZATION PLANTa
Controlled
Source VDC emission
Emission source designation^ factor0
Reactor B 3.5 kg/Mgd
Monomer recovery D 0.33 kg/Mg^
Unloading/storage A 2.1 kg/Mgd
Process fugitive G 2.8-11 kg/Mge
Total 1.4-7.0 kg/Mgd
aAny given plant may vary in configuration and level of control from
this hypothetical facility. The reader is encouraged to contact plant
personnel to confirm the existence of emitting operations and control
technology at a particular facility prior to estimating emissions
therefrom.
^Letters refer to vents designated in Figure 7.
cEmission factors in terms of kg/Mg refer to kilogram of vinylidene
chloride emitted per megagram of vinylidene chloride polymerized. In
cases where a particular source designation applies to multiple
operations, these factors represent combined emissions for all, not
each, of these operations within the hypothetical facility. The types
of controls employed were not reported.
^Based on industry estimates.
eBased on EPA projections of monomer emissions from small and medium
sized generic polymerization plants with quarterly inspection and
maintenances of valves, pumps, compressors, flanges, relief valves, and
process drains.29 Industry reports that more stringent inspection and
maintenance programs are practiced than are reflected in the factors
cited in this table. (See text for discussion.) These more stringent
measures result in fugitive emission control efficiencies as high as 90
to 95 percent from an uncontrolled situation where no significant
measures are taken for leak detection and repair .^> ^
40
-------
plant emissions are based on industry estimates in response to EPA
1 fi 2 S
surveys. v>*--> Data are not available on the specific controls used to
attain the reported emission rates. Techniques which can be used to
control process and storage emissions of monomers from polymerization
plants are identified in Table 9.
The emission rates given in Table 8 for process fugitive sources
are based on EPA estimates of emissions from typical small to medium
sized generic polymerization facilities using monthly inspection and
77
maintenance of fugitive sources The control efficiency of monthly
inspection and maintenance for fugitive emissions is about 30 percent.
Additional controls which might be used include double mechanical seals
on pumps, enclosure of pumps, rupture disks on relief valves, use of
welded pipe instead of flanges, special construction materials for
piping and valves, and intensive preventative maintenance during plant
shutdown. In addition, intensive inspection and maintenance programs
practiced at some plants can insure repair of most leaks within 1 day
instead of 1 month. With these additional controls, many plants have
achieved fugitive emission control efficiencies as high as 90 to 95
percent.18'19
Source Locations
Table 10 lists producers of VDC copolymers. The table also gives
plant location and identifies the types of VDC copolymer produced at
each facility.25'26'31
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43
-------
USE OF VIKYLIDENE CHLORIDE IN SPECIALTY CHEMICAL PRODUCTION
Vinylidene chloride is used as a chemical intermediate in the
production of chloroacetyl chloride. This use of VDC is minor in
comparison with its use in production of VDC copolymers. The structure
of chloroacetyl chloride is as follows:
Cl 0
I II
H-C-C
I I
H Cl
Its main use is in the manufacture of chloroacetophenone, the principal
ingredient in tear gas. It is also used in the manufacture of
7 Q
Pharmaceuticals. '
Process Description and Emissions
Information on the process used to produce chloroacetyl chloride
from VDC is not available, nor are data available to estimate VDC
emissions from the process. Dow Chemical reports no losses of VDC to
the environment from the process used in chloroacetyl chloride
production.'
Source Locations
The VDC process for chloroacetyl chloride is used by the Dow
Q
Chemical U.S.A., of Midland, Michigan. Production facilities are
18
located at Dow Chemical's Michigan Division plant at Midland.
44
-------
VINYLIDENE CHLORIDE COPOLYMER FABRICATION
When VDC is polymerized to produce VDC copolymers, some residual
VDC monomer remains in the polymer. During subsequent fabrication, when
the polymer is heated, dissolved, or otherwise treated, some of this
residual monomer evaporates, resulting in VDC emissions. The level cf
VDC residue in the polymer, and hence the magnitude of VDC emissions, is
dependent on the type of polymer, the comonomer used, and whether
stripping technology is used at the polymerization plant.
As noted in the previous section entitled POLYMERIZATION OF
VINYLIDENE CHLORIDE, VDC copolymers can be divided into two groups:
high-VDC copolymers (79 to 90 percent) used to form moisture and vapor
barrier coatings and films; and low-VDC copolymers (10 to 70 percent),
where VDC is added mainly to improve the flame retardant properties of
the finished polymer. VDC copolymers are also produced in a number of
forms: dried suspension resin, dried emulsion resin, latex, and polymer
solution. The types of VDC copolymers produced, production methods
used, and applications of the different types were summarized in Table 7
in the section entitled POLYMERIZATION OF VINYLIDENE CHLORIDE.
Generally, copolymer fabrication and copolymer production are carried
out at separate facilities,
Process Descriptions
Process descriptions are presented below for three methods of
fabricating high-VDC resins: coating of cellophane with copolymer
solution, coating of paper or plastic film with latex, and extrusion of
dried emulsion or suspension resin. Information was not available on
the specific methods used to fabricate low-VDC resins.
Cellophane Coating with Copolymer Solutions
Basic operations that may be used in the coating of cellophane with
5 O
VDC copolymer are shown in Figure 8. The inputs to this process are a
dried, high-VDC copolymer and pretreated cellophane film. The VDC
polymer is first dissolved in a solvent mixture in a closed tank. The
solvent mixture includes methyl ethyl ketone and tetrahydrofuran as the
45
-------
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46
-------
primary solvents and toluene as a diluent. Following the dissolution
step, additives such as wax, talc and silica are added in a closed
blender. The polymer solution is then fed to a dip tank, through which
a cellophane film strip is drawn.
After passing through the dip tank, the cellophane, now coated with
VDC copolymer solution, is run through a dryer consisting of two
chambers. In the first, dry air at 90 to 140°C is passed over the film,
n o
resulting in removal of the solvent. In the second chamber, the film
is conditioned in warm humid air.
Solvent laden vapor is collected from the drying chamber and ducted
to carbon absorption beds. Solvent stripped from the beds is purified
by distillation and recycled to the process. Heating air from the
second drying chamber is vented to the atmosphere.
Coating with Latex Copolyraer
As noted in the earlier section of POLYMERIZATION OF VINYLIBENE
CHLORIDE, a latex is a polymer emulsion in water. Materials typically
3 2
coated with high-VDC latex include paper products and plastic films. i
The latex may first be blended with additives, such as wax or
pigments, or diluted with additional water in a vented mixing tank. The
latex is pumped from the mixing tank to a holding tank and then to the
dip tank. The holding tank allows reduction of any foam that may form
during mixing. The material to be coated is rolled through the dip tank
and then to a drying oven. In the drying oven, water is removed from
the latex and the latex forms a barrier film. Both the dip tank and the
32
drying oven are vented to the atmosphere.
Extrusion of Thermoplastic Copolymer
The raw material for extrusion is dried emulsion or suspension
resin in the form of a powder or small granules. The polymer is mixed
with additives such as plasticizer in a high-intensity blender.
Mechanical energy dissipated in the blender heats the resin to about
170°C.^2 The blender is vented through a hood, usually to a roof stack.
From the high-intensity blender, the resin is fed to a ribbon blender,
where it is homogenized further and cooled. The blended resin may be
47
-------
stored prior to extrusion, or may be extruded immediately after
32
blending.
The extrusion process used on high-VDC copolymers is a blown-film
process. The resin compound is fed to an extruder, and is extruded
through a die in the form of a tube, becoming molten in the extrusion
process. The end of the tube is then pinched off, and air is blown into
the tube, expanding it into a bubble. The bubble is then cooled by
another blast of air and flattened before undergoing further processing
o 7
to form a film.JZ
Emissions
Emission sources from VDC copolymer fabrication include: polymer
storage vents, polymer mixing and blending vents, and finished polymer
drying. Emissions from individual sources have not been quantified.
However, total VDC emissions from copolymer fabrication can be estimated
by mass balance from the concentrations of residual VDC monomer in the
32
polymer entering and leaving the process.
EF - Ci - CQ
where EF = the overall uncontrolled emission factor for the
fabrication process, g VDC/Mg copolymer processed,
C- = the concentration of residual VDC monomer in the copolymer
entering the dissolver (Figure 8) ppmw, and
C = the concentration of residual VDC monomer in the copolymer
leaving the dryer (Figure 8),ppmw.
Table 11 summarizes data on residual VDC levels in raw and fabricated
high-VDC copolymers, and presents estimates of uncontrolled VDC emission
factors for high-VDC copolymer fabrication processes. Data are not
available on the residual VDC levels in low-VDC copolymers.
It should be noted that the mass balance technique of estimating
emissions involves the assumption that the only removal mechanism for
VDC from the copolymer is by emissions to the atmosphere. Thus,
emissions estimates developed by the mass balance technique would be
worst case estimates. In high temperature fabrication processes and
drying processes, some of the residual VDC may be polymerized.
48
-------
TABLE 11. ESTIMATES OF UNCONTROLLED EMISSION FACTORS FROM HIGK-VDC
COPOLYMER FABRICATION PROCESSES
Copolymer VDC
Process
Celophane coating
Latex coating
Extrusion
concentrations
Raw
resinb
(Ci)
10-120
50-2000
2-25
(ppmw)a
Processed
resinc
(c0)
nege
0-500
nege
Estimated
uncontrolled
emission
factor (g/Mg)d
10-120
50-1500
2-25
aReference 32.
°Resin entering the dissolver (Figure 8).
cResin leaving the dryer (Figure 8).
^Calculated from residual VDC levels. Emissions are expressed in terms
of grams of VDC per Mg of copolymer processed.
eneg = negligible.
49
-------
VDC emissions from copolymer fabrication generally are
uncontrolled. In the first stage of the drying operation for cellophane
coating, emissions containing solvent are captured and ducted to a
carbon adsorption system. The solvent is then desorbed and recycled to
the polymer dissolving operation. Some of the VDC vaporizing in the
drying process would be captured on the adsorbers. However, unless some
process is used to separate the captured VDC from the solvent, the VDC
would be recycled to the process and eventually emitted from the second
stage of the drying process, from the adsorber vent, or from another
vent.
Source Locations
Table 12 gives a list of plants fabricating high-VDC copolymers,
along with plant locations.31»32 ^e j£st includes plants that produce
PVDC-coated cellophane, plants that apply PVDC barrier-coated to paper
and plastics, and plants that extrude VDC copolymer.
Information is not available on the locations of fabrications of
low-VDC polymers. Such plants would be classified under Standard
Industrial Classification (SIC) code 282.
50
-------
TABLE 12. FACILITIES FABRICATING HIGH VINYLIDENE CHLORIDE
COPOLYMERS31*32
Company
Plant Location
Processes
Cellophane Barrier
coating coating
Resin
extrusion
Allied Chemical Corp.
American Bag and Paper
American Can Co.
Amtech, Inc.
Consolidated Paper
Crown Zellerbach
Cryovac Div. of
W. R. Grace
Curwood Div. of
Bemis
Daniels
Diversa-Pak
Dow Chemical
E.I. dupont de Nemours
Pittsville, PA
Philadelphia, PA
Neenah, WI
Odenton, MD
Wisconsin Falls, WI
Portland, OR
Iowa Park, TX
Sicpsonville, SC
New London, WI
Rhinelanaer, WI
St. Petersburg, FL
Midland, MI
Richmond, VA
Circleville, OH
X
X
X
X
X
X
X
X
X
X
FMC Corp.
Gordon Cartons
Green Bay Packaging
Hercules
Interstate Folding Box
Clinton, IA X
Tecumseh, KS X
Fredericksburg, VA X
Marcus Hook, PA X
Baltimore, MD
Green Bay, WI
Covington, VA
Middletown, OH
X
X
X
X
Continued
51
-------
TABLE 12. (Cont'd.) FACILITIES FABRICATING HIGH VINYLLDENE CHLORIDE
COPOLYMERS31.32
Company
Plant Location
Processes
Cellophane Barrier
coating coating
Resin
extrusion
Michigan Carton Co,
Milprint
Minnesota Mining and
Manufacturing
Olin Corp.
Olinkraft
Oscar Mayer
Rexham
Rhinelander Div. of
St. Regis
Sealed Air Corp.
Standard Packaging
Thilmany
Union Carbide Corp.
Z umbr i 1
Battle Creek, MI
Milwaukee, WI
Decatur, AL
Pisgah Forest, NC
Covington, IN
West Monroe, LA
Chicago, IL
Davinport, IA
Los Angeles, CA
Madison, WI
Nashville, TN
Philadelphia, PA
Memphis, TN
Rhinelander, WI
Fairlawn, NJ
Clifton, NJ
Kaukauna, WI
Centerville, IA
Cincinnati, OH
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Note: This listing is subject to change as market conditions change,
facility ownership changes, plants are closed, etc. The reader
should verify the existence of particular facilities by consulting
current listings and/or the plants themselves. The level of VDC
emissions from any given facility is a function of variables such as
capacity, throughput and control measures, and should be determined
through direct contacts with plant personnel.
52
-------
VOLATILIZATION FROM WASTE TREATMENT, STORAGE, AND DISPOSAL
Considerable potential exists for emissions of volatile substances,
including VDC, from waste treatment, storage, and disposal facilities.
VDC is expected to be present in the following wastes: still bottoms
and wastewater from VDC production, perchloroethylene and
trichloroethylene production, and trichloroethane production; wastewater
and off-specification polymer from VDC polymerization; and still bottoms
and wastewater from specialty chemical production processes where VDC is
used as a feedstock. (See separate sections on emissions from these
processes.) In addition, VDC may be present in wastes from other
processes.
Potential Sources
VDC may be emitted when waste containing VDC is present in surface
impoundments for treatment and storage of wastewater, open treatment and
storage tanks, and land-treatment areas for solid wastes and sludges.
The above treatment and storage facilities may be located at the site of
generation of the waste, or at a separate commercial waste treatment
plant. In addition, publicly owned treatment works (POTWs) may emit VDC
if they receive wastewater from plants producing VDC either as a main
product or as a byproduct, or from plants using VDC as an intermediate.
Volatile compounds also may be emitted from solid wastes during and even
after disposal in a covered landfill. Reference 33 summarizes general
theoretical models for estimating volatile substance emissions from
generic waste treatment, storage, and disposal operations, including
surface impoundments, landfills, land treatment (landfarming),
wastewater treatment, and drum handling and storage operations. If
facilities of the above types are known to handle wastes containing VDC,
the potential for air emissions should be considered.
Emissions
A pilot-scale study was conducted by EPA to evaluate the partioning
of several volatile organic pollutants, including VDC, in conventional
wastewater treatment processes. The tested wastewater treatment system
53
-------
consisted of a sequence of primary clarifier, aeration basin, and
secondary aeration basin. Wastewater influent contained an average of
10.7 parts per billion (ppb) VDC. Over 98 percent of the VDC entering
the pilot treatment system was found to evaporate, with about 65 percent
evaporating from the primary clarifier and 33 percent from the aeration
basin. The 98 percent evaporation rate corresponds to an emission
factor of 0.98 grams VDC per gram VDC in the wastewater feed. It should
be noted that these tests were conducted at low VDC concentrations
(about 10 ppb); the emission factor may change at higher concentrations.
54
-------
SECTION 5
SOURCE TEST PROCEDURES
Vinylidene chloride emissions can be measured using EPA Reference
Method 23, which was proposed in the Federal Register on June 11,
1980. The method has not been validated by EPA for vinylidene
chloride, but a similar analytical procedure has been used to measure
occupational exposures to VDC. °>J'
In Method 23, a sample of the exhaust gas to be analyzed is drawn
into a Tedlar or aluminized Mylar bag as shown in Figure 9. Tedlar is
O Q
considered a more reliable bag material than Mylar for VDC. ° The bag
is placed inside a rigid leak proof container and evacuated. The bag is
then connected by a Teflon^ sampling line to a sampling probe (stainless
steel, Pyrex glass, or Tefloir*) at the center of the stack. The sample
is drawn into the bag by pumping air out of the rigid container.
The sample is then analyzed by gas chromatography (GC) coupled with
flame ionization detection (FID). Analysis should be conducted within
one day of sample collection. The recommended GC column is 3.05 m by
3.2 mm stainless steel, filled with 20 percent SP-2100/0.1 percent
Carbowax 1500 on 100/120 Supelcoport. This column normally provides an.
adequate resolution of halogenated organics. (Where resolution
interferences are encountered, the GC operator should select the column
best suited to the analysis.) The column temperature ahould be set at
100°C. Zero helium or nitrogen should be used as the carrier gas at a
flow rate of approximately 20 ml/min.
The peak area corresponding to the retention time of vinylidene
chloride is measured and compared to peak areas for a set of standard
gas mixtures to determine the VDC concentration. The range of the
method is 0.1 to 200 ppm; however the upper limit can be extended by
extending the calibration range or diluting the sample. To avoid
absorption of VDC by the Tedlar bag, the sample should be analyzed as
55
-------
FILTER
(GLASS WOOL)
QUICK
CONNECTS
SAMPLING
BAG
FLOW
METER
CHARCOAL
TUBE
RIGID
LEAKPROOF
CONTAINER
Figure 9. Method 23 sampling train.
35
56
-------
soon as posible after collection, preferably on the same day. The
method does not apply when vinylidene chloride is contained in
particulate matter.
57
-------
REFERENCES
1. Hushon, J., and M. Kornreich. Air Pollution Assessment of
Vinylidene Chloride. EPA-450/3-78-015. U.S. Environmental
Protection Agency, Washington, DC. February 1978. pp. 7-20.
2. Grayson, M., ed. Kirk-Othmer Encyclopedia of Chemical Technology.
Third Edition, Volume 23. John Wiley and Sons, New York, NY, 1983.
pp. 764-798.
3. Edney, E., S. Mitchell, and J. Bufalini. Atmospheric Chemistry of
Several Toxic Chemicals. EPA-600/3-82-092. U.S. Environmental
Protection Agency, Research Triangle Park, NC. November 1982.
pp. 31-35.
4. Cuppitt, Larry. Fate of Toxic and Hazardous Materials in the Air
Environment. EPA-600/3-80-084. U.S. Environmental Protection
Agency, Research Triangle Park, NC. August 1980. pp. 3-6.
5. Standifer, R.L., and J.A. Key. Report 4: 1,1,1-Trichloroethane,
Perchloroethylene, Trichloroethylene, and Vinylidene Chloride. In:
Organic Chemical ManufacturingVolume 8: Selected Processes.
EPA-450/3-80-028c. U.S. Environmental Protection Agency, Research
Triangle Park, NC. December 1980. pp. III-l to 111-17.
6. Neufeld, M.L., M. Sittenfield, M.J. Plotkin, K.F. Wolk, and R.E.
Boyd. Market Input/Output StudiesTask I: Vinylidene Chloride.
EPA-560/6-77-033. U.S. Environmental Protection Agency, Washington,
DC. October 1977. pp. 67-70, 156-163.
7. Hawley, Gessner G. The Condensed Chemical Dictionary. Tenth
Edition. Van Nostrand Reinhold Co., New York, NY. 1981. pg. 232.
8. Modern Plastics Encyclopedia. Modern Plastics. 59(10A) :113-114.
October 1982.
9. Reference 6. pg. 156.
10. Reference 5. pp. II-l to II-6.
11. Reference 5. pp. 111-15 to 111-17.
*
12. Reference 6. pp. 67-70.
13. Reference 5. pp. IV-15, IV-18, and IV-19.
14. Reference 5. pp. V-5 to V-7.
58
-------
15. Mascone, D., U.S. Environmental Protection Agency. Memo and
Addendum to J.R. Farmer, EPA, entitled "Thermal Incinerator
Performance for NSPS", June 11, 1980.
16. Eisen, P., M. Sanders, and M. Samuels. Human Exposure to
Atmospheric Concentrations of Vinylidene Chloride. Prepared by
Wapora, Inc. (Project 507-13) for the U.S. Environmental Protection
Agency, Research Triangle Park, NC. February 4, 1982. pp. 2-1
and D-l to D-3.
17. Reference 6. pp. 84-86.
18. Letter from Alice R. Mayer, Chemical Manufacturers' Association, to
Thomas F. Lahre, U.S. Environmental Protection Agency. March 19,
1985.
19. Letter from Thomas E. Lingafelter, Dow Chemical, to Thomas F.
Lahre, U.S. Environmental Protection Agency. February 15, 1985.
20. 1983 Directory of Chemical Producers, United States of America.
SRI International. Menlo Park, CA. 1983.
21. Reference 5. pp. III-8 to 111-14.
22. Reference 5. -pp. IV-11 to IV-18.
23. Reference 5. pp. III-4 to III-8.
24. Reference 5. pp. IV-6 to IV-10.
25. Vinylidene Chloride Monomer Emissions from the Monomer, Polymer,
and Polymer Processing Industries. Prepared by Arthur D. Little,
Inc. (ADL Reference 76086-31) for the U.S. Environmental Protection
Agency, Research Triangle Park, NC. April 1976. pp. 16-42.
26. Reference 6. pp. 9-20.
27. Wilkins, Glynda E. Industrial Process Profiles for Environmental
Use: Chapter 10. Plastics and Resins Industry. EPA-600/2-77-023j.
U.S. Environmental Protection Agency, Research Triangle Park, NC.
February 1977. pp. 55-58.
28. Synthetic Fiber Production FacilitiesBackground Information for
Proposed Standards. EPA-450/3-82-011a. U.S. Environmental
Protection Agency, Research Triangle Park, NC. October 1982.
pp. 3-1 to 3-27.
29. Control of Volatile Organic Compound Leaks from Synthetic Organic
Chemical and Polymer Manufacturing Equipment. EPA 450/3-83-006.
U.S. Environmental Protection Agency, Research Triangle Park, NC.
March 1984. pg. 4-3.
59
-------
30. Vinyl Chloride - A Review of National Emission Standards.
EPA-450/3-82-003, U.S. Environmental Protection Agency, Research
Triangle Park, NC. February 1982. pg. 4-2.
31. Reference 16. pp. 1-3 to 1-4.
32. Reference 25. pp. 43-61.
33. Evaluation and Selection of Models for Estimating Air Emissions
from Hazardous Waste Treatment, Storage and Disposal Facilities.
EPA-450/3-84-020. Prepared for the U.S. Environmental Protection
Agency by GCA, Corp., Bedford, MA. Dec. 1984.
34. Petrasek, A.C., Jr., Barry M. Austern, and Timothy W. Neiheisel.
Removal and Partitioning of Volatile Organic Priority Pollutants in
Wastewater Treatment. Paper presented at the Ninth U.S.-Japan
Conference on Sewage Treatment Technology, Tokyo, Japan, September
13-29, 1983. 20 pp.
35. Method 23. Determination of Halogenated Organics from Stationary
Sources. Federal Register. 45(114)=39776-39784. June 11, 1980.
36. Forest, Denis. A Sampling and Analytical Method for Vinylidene
Chloride in Air. American Industrial Hygiene Association Journal.
October 1979. pp. 888-893.
37. Severs, L.W. and L.K. Skory. Monitoring Personnel Exposure to
Vinyl Chloride, Vinylidene Chloride and Methyl Chloride in an
Industrial Work Environment. American Industrial Hygiene
Association Journal. September 1975. pp. 669-676.
38. Telecon. Joseph Knoll, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, with William Battye,
GCA/Technology Division. EPA Reference Method 23. January 26,
1984.
39. Memorandum from R. Rosensteel, U.S. Environmental Protection Agency
to T. Lahre, U.S. Environmental Protection Agency, entitled "Review
of Draft Reports on Emission Factors for Potentially Toxic
Substances." November 10, 1984.
60
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APPENDIX A
PROCESS FUGITIVE EMISSION CALCULATIONS
FOR VINYLIDENE CHLORIDE PRODUCTION
FROM 1,1,2-TRICHLOROETHANE
Fugitive emissions of vinylidene chloride (VDC) and other volatile
organics result from leaks in process valves, pump seals, compressors,
sample connections, open-ended lines and pressure relief valves. Fugi-
tive VDC emission rates from these sources were based on a process flow
diagram (Figure 2), process operation data, a fugitive source inventory
for a hypothetical plant, and EPA emission factors for process fugitive
2
sources.
The first step in estimating fugitive emissions of VDC was to list
the process streams in the hypothetical plant. Their phases (i.e.,
gaseous or liquid) were then identified from the process flow diagram
and their compositions estimated. For the reactor product stream, the
composition was estimated based on reaction completion data. For a
stream from a distillation column or other separator, the composition
was estimated based on the composition of the input stream to the unit,
the unit description, and the general description of the stream of
interest (i.e. overheads, bottoms, or sidedraw).
After the process streams were characterized, the number of valves
per stream were estimated by dividing the total number of valves at the
plant equally among the process streams. Similarly, pumps were
apportioned equally among liquid process streams, and relief valves were
apportioned equally among all reactors, columns, and other separators.
The locations of any compressors were determined from the process flow
diagram. Although the above sources probably are not apportioned
equally among the process lines at an actual plant, the equal
apportionment algorithm provides the best estimate of the number of
sources per line given the available data.
Emissions were then calculated for pumps, compressors, valves in
liquid and gas line service, and relief valves. Emissions from flanges
A-l
-------
and drains are minor in comparison with these sources and were therefore
neglected. Fugitive emissions from a particular component were assumed
to have the same composition as the process fluid flowing through each
component. For valves in liquid service, for instance, VDC emissions
were determined by taking the product of: (1) the total number of
liquid valves in VDC service; (2) the average VDC content of the streams
passing through these valves; and (3) the average fugitive emission rate
per valve per unit time as measured by EPA. Emissions from valves in
gas service, pumps and compressors were calculated in the same manner.
For relief valves, fugitive emissions were assumed to have the composi-
tion of the overhead stream from the reactor or column served by the
relief valve. Emissions from the various fugitive source types were
summed to obtain total process fugitive emissions of VDC.
Because emissions from process fugitive sources do not depend on
their size, but only on their number, total process fugitive emissions
are not dependent on plant capacity. Thus, the overall emissions are
expressed in terms of kilograms per hour of operation.
HYPOTHETICAL PLANT FUGITIVE SOURCE INVENTORY
725 process valves
15 pumps (not including spares)
2 compressors
25 safety relief valves
PROCESS LINE COMPOSITION AND FUGITIVE SOURCE INVENTORY
Of the approximately 16 major process lines in the production
process, 9 contain at least some fraction of volatile organics compounds
(VOC) and 6 contain vinylidene chloride (VDC). Compositions of the
major process streams (identified in Figure 2 in the section or VINYLI-
DENE CHLORIDE PRODUCTION) are estimated in Table A-l.
A fugitive emission equipment count was not available for a VDC
production plant. However, studies of other synthetic organic chemical
manufacturing plants indicate that a typical fugitive equipment count is
as follows:
A-2
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TABLE A-l. ESTIMATED PROCESS LINE COMPOSITION IN VDC PRODUCTION*
Stream
number3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Phase
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Liquid
Vapor
Liquid
Liquid
Stream composition
Water NaOH NaCl
0
1.00
0
0.75
0
0.77
0.90
0
0.90
0.90
0
0
0.90
0
0
0
1.000
0
0
0.061
0
0.011
0.012
0
0.012
0.012
0
0
0.012
0
0
0
0
0
0
0
0
0.073
0.086
0
0.086
0.086
0
0
0.086
0
0
0
(weight fraction)
C12HC-CH2C1 VDC
0
0
1.000
0.191
0
0.024
0
0.164
0
0
0.164
0.164
0
0.164
1.000
0
0
0
0
0
0
0.121
0
0.836
0
0
0.836
0.836
0
0.836
0
1.000
Other
0
0
0
0
1.00
0
0
0
0
0
0
0
0
0
0
0
aStream numbers correspond to those shown in Figure 2.
A-3
-------
15 process valves per major process line,
1 pump (not including spares) per major liquid process line,
1 compressor for each gas line requiring pressurization, and
2 relief valves per pressure vessel or column.
EMISSION CALCULATIONS
VDC emissions from valves in liquid and gas service, and for pumps
were calculated as follows:
(Total VDC emission rate for stream type) =
(# of streams) X
(Average VDC content for stream type) X
(# of pumps or valves per stream) X
(Emission rate for individual rate for individual pumps or
valves)
These calculations are summarized in Table A-2. Similarly, emissions
from relief valves were calculated for each vessel or column processing
VDC:
(VDC emissions rate) =
(2 relief valves per vessel) X
(VDC fraction in vessel overheads) X
(0.104 kg emissions/hr/relief valve)
These calculations are summarized in Table A-3. No compressors are
expected to be in VDC service in the VDC-from-l,l,2-trichloroethane
process.
Total uncontrolled process fugitive emission rates for VDC
production are given in Table A-4, along with controlled emission rates
for various combinations of emission reduction techniques. The emission
reduction techniques studied were quarterly and monthly inspection of
valves and pumps, the use of double mechanical sealed pumps, and the use
of rupture disks in tandem with or in place of relief valves.
A-4
-------
TABLE A-2. ESTIMATED VDC EMISSIONS FROM VALVES AND PUMPS
Source type
Valves
vapor
liquid
Pumps
TOTAL
Number
of
streams
2
3
3
Average
VDC weight
fraction3
0.84
0.60
0.60
Number
of
sources
30
45
3
Source VOC
emission rate^
(kg/hr-source)
0.0056
0.0071
0.0494
Emissions
(kg/hr)
0.140
0.191
0.089
0.42
aFraction of VOC stream in each source type comprised of VDC.
A-5
-------
TABLE A-3. ESTIMATED VDC EMISSIONS FROM RELIEF VALVES
Vessel
Reactor
Phase separator
Drying column
Finishing column
Stripping column
Number of
relief
valves
2
2
2
2
2
VDC weight
fraction in
overheads
0.56
0.56
0.50
0.50
0.50
TOTAL
Emissions3
(kg/hr)
0.12
0.12
0.10
0.10
0.10
0.54
aRelief valve emission rate of 0.104 kg/hr-valve was used to calculate
emissions.2
A-6
-------
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A-7
-------
REFERENCES FOR APPENDIX
1. Standifer, R.L., and J.A. Key. Report 4: 1,1,1-Trichloroethane,
Perchloroethy lene, Trichloroethy lene, and Vinylidene Chloride. In:
Organic Chemical ManufacturingVolume 8: Selected Processes.
EPA-450/3-80-028c, U.S. Environmental Protection Agency, Research
Triangle Park, NC. December 1980. pp. IV-1 to IV-22.
2. Fugitive Emission Sources of Organic CompoundsAdditional
Information on Emissions, Emission Reductions, and Costs.
EPA-450/3-82-010, U.S. Environmental Protection Agency, Research
Triangle Park, NC. April 1982.
A-8
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before complenngi
1. REPORT NO.
EPA-450/4-84-007k
'3. RECIPIENT'S ACCESSION NO.
1. TITLE AND SUBTITLE
Locating And Estimating Air Emissions From Sources
Of Vinvlidene Chloride
5 REPORT DATE
! September 1985
6. PERFORMING ORGANIZATION COOS
7 AUTHOR'S!
8. PERFORMING ORGANIZATION RSPCR"!
9 PERFORMING ORGANIZATION NAME AND ADDRESS
10 PRCGRAV cLEVENT NO
ill CONTRACT; GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
113. T/PE OF REPORT AND PERIOD COVERED
Office Of Air Ouality Planning And Standards (MD 14) l_
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
: 14. SPONSORING AGENCY CODE
1i. SUPPLEMENTARY NOTES
EPA Project Officer: Thomas F. Lahre
16 ABSTRACT
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 vinylidene chloride. Its intended audience
includes Federal, State and local air pollution personnel and others interested
in locating potential emitters of vinylidene chloride in making gross estimates of air
emissions therefrom.
This document presents information on 1) the types of sources that may emit
vynilidene chloride, 2) process variations and release points that may be expected
within these sources, and 3) available emissions information indicating the
potential for vinylidene chloride release into the air from each operation.
17.
a
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Vinylidene Chloride
Emissions Sources
Locating Air Emission Sources
Toxic Substances
13.
DISTRIBUTION STATEMENT
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74
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