United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Cincinnati OH 45268
EPA-600/2-78-004C
March 1978
Research and Development
LvEFft
Source Assessment:
Plastics Processing,
State of the Art
Environmental Protection
Technology Series
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U S, Environmental
Protection Agency, have been grouped into nine series These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields
The nine series are
1 Environmental Health Effects Research
2. Environmental Protection Technology
3 Ecological Research
4 Environmental Monitoring
5 Socioeconomic Environmental Studies
6 Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8 "Special" Reports
9 Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/2-78-004C
March 1978
SOURCE ASSESSMENT:
PLASTICS PROCESSING
State of the Art
by
T. W. Hughes, R. F. Boland, and G. M. Rinaldi
Monsanto Research Corporation
Dayton, Ohio 45407
Contract No. 68-02-1874
project Office
Ronald J. Turner
Industrial Pollution Control Division
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th float
Chicago, It 60604-3590
-------
DISCLAIMER
This report has been reviewed by the Industrial Environmental
Research Laboratory-Cincinnati, U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify
that the contents necessarily reflect the views and policies of
the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
11
-------
FOREWORD
When energy and material resources are extracted, processed,
converted, and used, the related pollutional impacts on our
environment and even on our health often require that new and
increasingly more efficient pollution control methods be used.
The Industrial Environmental Research Laboratory - Cincinnati
(lERL-Ci) assists in developing and demonstrating new and
improved methodologies that will meet these needs both effi-
ciently and economically.
This report contains an assessment of air emissions from the
plastics processing industry. This study was conducted to pro-
vide a better understanding of the distribution and characteris-
tics of emissions from plastics processing operations. Further
information on this subject may be obtained from the Organic
Chemicals and Products Branch, Industrial Pollution Control
Division.
David G. Stephan
Director
Industrial Environroental Research Laboratory
Cincinnati
-------
PREFACE
The Industrial Environmental Research Laboratory (IERL) of the
U.S. Environmental Protection Agency (EPA) has the responsibility
for insuring that pollution control technology is available for
stationary sources to meet the requirements of the Clean Air Act,
the Federal Water Pollution Control Act, and solid waste legisla-
tion. If control technology is unavailable, inadequate, or
uneconomical, then financial support is provided for the develop-
ment of the needed control techniques for industrial and extrac-
tive process industries. Approaches considered include: process
modifications, feedstock modifications, add-on control devices,
and complete process substitution. The scale of the control
technology programs ranges from bench- to full-scale demonstra-
tion plants.
IERL has the responsibility for developing control technology for
a large number of operations (more than 500) in the chemical and
related industries. As in any technical program, the first step
is to identify the unsolved problems. Each of the industries is
to be examined in detail to determine if there is sufficient
potential environmental risk to justify the development of con-
trol technology by IERL.
Monsanto Research Corporation (MRC) has contracted with EPA to
investigate the environmental impact of various industries that
represent sources of pollutants in accordance with EPA's respon-
sibility, as outlined above. Dr. Robert C. Binning serves as MRC
Program Manager in this overall program, entitled "Source Assess-
ment," which includes the investigation of sources in each of
four categories: combustion, organic materials, inorganic mater-
ials, and open sources. Dr. Dale A. Denny of the Industrial
Processes Division at Research Triangle Park serves as EPA Proj-
ect Officer for this series. Reports prepared in this program
are of two types: Source Assessment Documents, and State-of-the-
Art Reports.
Source Assessment Documents contain data on pollutants from
specific industries. Such data are gathered from the literature,
government agencies, and cooperating companies. Sampling and
analysis are also performed by the contractor when the available
information does not adequately characterize the source pollut-
ants. These documents contain all of the information necessary
for IERL to decide whether a need exists to develop additional
control technology for specific industries.
-------
State-of-the-Art Reports include data on pollutants from specific
industries which are also gathered from the literature, govern-
ment agencies and cooperating companies. However, no extensive
sampling is conducted by the contractor for such industries.
Results from such studies are published as State-of-the-Art
Reports for potential utility by the government, industry, and
others having specific needs and interests.
This State-of-the-Art Report contains data on air emissions from
plastics processing. This project was initiated by the Chemical
Processes Branch of the Industrial Processes Division at Research
Triangle Park; Mr. Kenneth Baker served as EPA Project Leader.
The project was transferred to and completed by the Industrial
Pollution Control Division, lERL-Cincinnati, in October 1975; Mr.
Ronald J. Turner of the Organic Chemicals and Products Branch
served as EPA Project Leader from that time through completion of
the study.
-------
ABSTRACT
This document reviews the state of the art of air emissions from
plants that manufacture marketable products via plastics process-
ing. The composition, quantity, and rate of emissions are
described.
The plastics processing industry in the United States produced
1.19 x 107 metric tons of finished goods in 1976 using the fol-
lowing types of plastics: acrylic, cellulosic, epoxy, nylon,
phenolic, polyacetal, polycarbonate, polyester, high-density
polyethylene, low-density polyethylene, polypropylene, polyester
and styrene copolymers, polyurethane, polyvinyl chloride and
copolymers, reinforced thermoplastics, and urea and melamine.
These polymers were converted into fabricated plastic products,
film, sheet, rod, tube, nontextile monofilaments, and regenerated
cellulose products.
To assess the severity of emissions from this industry, 16 repre-
sentative plants (1 plant for each plastic type) were defined
based on the results of this study. Source severity was defined
as the ratio of the time-averaged maximum ground level concentra-
tion of a pollutant to the primary ambient air quality standard
for criteria pollutants. For representative plants converting
3,330 metric tons of a particular resin into the appropriate
product, the hydrocarbon source severities ranged from 4.2 to 98
for polyacetal and polyurethane plastic types, respectively, and
the particulate source severities ranged from 0.94 for 12 differ-
ent plastic types to 11 for polyester.
The mass emissions from plastics processing in 1981 are expected
to be 54% greater than 1976 emissions if no further implementa-
tion of existing control technology occurs. Plastics processing
contributes 2.8% of the national hydrocarbon emissions and 0.12%
of the national particulate emissions. On a state basis, plas-
tics processing contributes from 0.04% to 8.96% of the hydro-
carbon emissions and from 0.00% to 2.59% of the particulate
emissions, depending on which state is considered.
Control technology which is currently available and potentially
applicable to plastics processing plants can be divided into con-
trols for hydrocarbons and for particulates. Hydrocarbon control
technology includes adsorption, absorption, incineration, and
condensation. Particulate control technology consists of wet
scrubbers, fabric filters, and mist eliminators.
-------
This report was submitted in partial fulfillment of Contract No.
68-02-1874 by Monsanto Research Corporation under the sponsorship
of the U.S. Environmental Protection Agency. This report covers
the period December 1974 to July 1977, and the work was completed
as of July 1977.
VII
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CONTENTS
Foreword iii
Preface iv
Abstract vi
Figures xi
Tables xii
Abbreviations and Symbols xiii
Conversion Factors and Metric Prefixes xv
1. Introduction 1
2. Summary 2
3. Source Description 7
Source definition 7
Geographical distribution 23
4. Emissions 27
Selected pollutants and their characteristics . . .27
Emission factors 27
Definition of a representative source 29
Source severity 29
5. Control Technology 36
Hydrocarbons 36
Particulate 44
6. Growth and Nature of the Industry 52
Acrylic 54
Cellulosic 54
Epoxy 54
Nylon 54
Phenolic 56
Polyacetal 56
Polycarbonate 56
Polyester 56
Polyethylene 57
Polypropylene 57
Polystyrene and styrene copolymers 57
Polyurethane foam 57
Polyvinyl chloride and copolymers 58
Reinforced thermoplastics 58
Urea and melamine 58
References 59
Appendices
A. Consumption and processing data for plastic resins . . .64
B. Derivation of source severity equations 73
IX
-------
CONTENTS (continued)
C. Input data and output from affected population
calculations 85
D. Sample calculations 86
Glossary 88
x
-------
FIGURES
Number Pac
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Dip-coating line
Knife-over-roll coating
Reverse-roll coating
A typical single-stage, single-screw extruder for
plastics
Production of plastic film by slot-die extrusion. .
Production of plastic film by circular-die
extrusion
Schematic diagram of impregnation and drying
operations in laminated plastics production . . .
Schematic diagram of a plunger-type injection-
molding machine
Basic transfer mold operation
Geographical distribution of plastics processing
plants
Carbon adsorption system
Catalytic afterburner
Centrifugal spray scrubbers
Impingement plate scrubber
Venturi scrubber
Packed scrubbers
Wet-fiber mist eliminator
Projected growth of plastics consumption
17
17
17
18
19
19
21
23
24
26
39
42
46
46
47
48
51
55
-------
TABLES
Number
1 Processing of Plastics ............... 3
2 Emission Factors and Annual Mass of Emissions from
Plastics Processing ............... 4
3 Source Severities for Criteria Pollutants Emitted
from 16 Representative Plastics Processing Plants 5
4 Geographical Distribution of Plastics Processing. . 25
5 Total Hydrocarbon and Total Particulate Emission
Factors for Plastics Processing ......... 28
6 Maximum Ground Level Concentrations for Materials
Emitted from Plastics Processing ......... 30
7 Source Severities for Plastics Processing ..... 31
8 National Masses of Hydrocarbon Emissions from
Plastics Processing ............... 33
9 National Masses of Particulate Emissions from
Plastics Processing ............... 33
10 State Masses of Emissions from Plastics Processing. 34
11 Populations Exposed to_Plastics Processing
Emissions for Which /F>I ............ 35
12 Plastics Consumption and Estimated Growth ..... 53
xn
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ABBREVIATIONS AND SYMBOLS
A
AAQS
a, b, c, c
c2, c3, d,
fl'fiTfz!
AEROS
AR
BR
CO
DP
e
KF
EF.
i
F.
i
h
H
HOPE
HMDA
i
LDPE
n
NEDS
NO
x
P1
PP
— area affected by source severity greater than
1.0
— primary ambient air quality standard
constants used in estimating horizontal or
vertical dispersion
Aerometric and Emissions Reporting System
term equated to Q/acfru
term equated to -H2/2 c2
carbon monoxide
affected population density
2.72
"overall" emission factor
product of emission factor and fraction of
plastic processed per process operation
health hazard factor
fraction of plastic processed per process
operation or handling method
average emission height
height of emission release
high-density polyethylene
hexamethylene-diamine
process operation or handling method in a series
or summation
low-density polyethylene
number of molecules
National Emissions Data System
nitrogen oxides
total affected population
polypropylene
XTM
-------
ABBREVIATIONS AND SYMBOLS (continued)
ppm — parts per million
Q — mass emission rate
R, R1 — aromatic or aliphatic hydrocarbon group
S — source severity
SO — sulfur oxides
x
t — time-averaging period for criteria pollutants
TDI — toluene diisobyanate
t — short-term averaging time
u -- wind speed
u -- average wind speed
VCM -- vinyl chloride monomer
x -- downwind emission dispersion distance from
source of release
x -- distance where maximum concentration occurs
max
y -- horizontal distance from centerline of
dispersion
a -- standard deviation of horizontal dispersion
o -- standard deviation of vertical dispersion
t*
X -- downwind ground level concentration at reference
coordinate x and y with emission height of H
X -- time-averaged concentration
— maximum around level concentration
^
Y — time-averaged maximum ground level concentration
Amax ^ ^
Xiv
-------
CONVERSION. FACTORS AND METRIC PREFIXES
| To convert from
Degree Celsius (°C)
Gram/second (g/s)
Kilogram (kg)
Kilometer2 (km2)
Meter (m)
Meter2 (m2)
Meter3 (m3)
Metric ton
Metric ton
Metric ton
Pascal (Pa)
CONVERSION FACTORS
To
Degree Fahrenheit
Pound/hr
Pound-mass (avoirdupois)
Mile2
Foot
Foot2
Foot3
Pound-mass
Kilogram
Ton (short, 2,000 pound mass)
Pound-force/inch2 (psi)
Multiply by
t° = 1.8 t° + 32
7.937
2.205
2.591
3.281
1.076 x 101
3.531
10
1
2.205 x 103
1.000 x 103
1.585 x I0~k
1.450 x ID"1*
METRIC PREFIXES
Prefix
Mega
Micro
Milli
Kilo
Symbol Multiplication factor
M
P
m
k
106
10~6
io-3
103
1 MJ =
1 g = 1
1 mg =
1 kPa =
Example
1 x IO6 joules
x 10~6 gram
1 x 10~3 gram
1 x IO3 pascals
Metric Practice Guide. ASTM Designation E 380-74, American
Society for Testing and Materials, Philadelphia, Pennsylvania,
November 1974. 34 pp.
xv
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SECTION 1
INTRODUCTION
Plastics processing operations are performed on polymeric materi-
als or systems to increase their utility. These operations
involve chemical reactions, forming or shaping due to flow char-
acteristics, and/or permanent changes in physical characteristics,
The products of plastics processing are: adhesives, coatings,
extruded goods, film and sheet, foams, laminates, and molded
goods. Excluded from plastics processing are the operations
performed in the manufacture of polymers or resins.
This document evaluates the environmental impact of atmospheric
emissions from plants that manufacture marketable products via
plastics processing. Sources of information used were trade
journals, reference books, government reports, and personal com-
munications with industry contacts. Section 2 summarizes the
major results of this assessment of plastics processing. A
detailed description of the raw materials and the production
methods used by the industry is given in Section 3, along with a
geographical distribution of plant sites and plastics consump-
tion. The amounts and effects of uncontrolled atmospheric emis-
sions from 16 representative plastics processing plants are
quantified in Section 4. Control technology potentially appli-
cable to these emissions is considered in Section 5. Consumption
trends in the plastics processing industry are analyzed in
Section 6. Appendix A presents 1976 consumption and processing
data for each of the 16 plastic types considered in this study.
Appendix B provides detailed derivations of equations used to
calculate the severity of a point source of air pollution.
Appendix C is a listing of input data and output from calcula-
tions of the number of people affected by potentially hazardous
concentrations of materials emitted from the representative
plastics processing plants. Sample calculations are outlined in
Appendix D.
-------
SECTION 2
SUMMARY
The plastics processing industry in the United States produced
1.19 x 107 metric tons^ of finished goods in 1976 using the fol-
lowing types of plastics: acrylic, cellulosic, epoxy, nylon,
phenolic, polyacetal, polycarbonate, polyester, high-density
polyethylene, low-density polyethylene, polypropylene, polysty-
rene and styrene copolymers, polyurethane, polyvinyl chloride
and copolymers, reinforced thermoplastics, and urea and melamine.
These polymers were converted into fabricated plastics products,
film, sheet, rod, tube, nontextile monofilaments, and regener-
ated cellulose products.
In 1972, there were 7,698 plastics processing plants in the
United States. The majority of these plants are located in the
following industrialized states: California, Illinois, Indiana,
Massachusetts, Michigan, New Jersey, New York, Ohio, Pennsyl-
vania, and Texas. Together, these 10 states account for more
than 67% of the nation's plastics processing capacity.
Raw materials consumed in plastics processing plants consist of
plastic resins, chemicals, and additives. Chemicals and addi-
tives include antioxidants, antistatic agents, catalysts, color-
ants, fillers, flame retardants, lubricants, organic peroxides,
plasticizers, solvents, stabilizers, and ultraviolet absorbers.
These materials are blended together and converted into final
products as a result of chemical reactions (e.g., cross-linking),
application of heat and pressure (e.g., extrusion or molding),
or changes in physical characteristics (e.g., foam generation).
Seven process operations are performed in plastics processing
plants: adhesives production, coating, extrusion, film and
sheet production, foam generation, lamination, and molding.
These operations convert raw resins into marketable items, such
as plastic bottles, meat packaging wrap, pipe and tubing, foam
mattresses, upholstery, and pleasure boat hulls. The processing
methods used for 16 different plastics in 1976 are presented in
Table 1, together with the domestic consumption of each type of
plastic.
1 metric ton equals 103 kilograms, which equals 2,205 pounds;
conversion factors and metric prefixes are provided in the
prefatory pages.
-------
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The types of emission sources to be found in a plastics processing
plant are listed below:
Storage
Conveying
Pretreatment
• Dry blending
• Hot roll mixing
Grinding
Processing
• Adhesives production
• Coating
• Extrusion
• Film and sheet
production
• Foam generation
• Lamination
• Molding
Materials emitted to the atmosphere include particulates and hydro-
carbons. The particulates are resin powders, solid additives,
and hydrocarbon aerosols. Hydrocarbons consist of blowing agents,
monomers, dimers, solvents, and additives introduced during pro-
cessing .
Emission factors (assuming no control) for the handling methods
and the unit operations of plastics processing and the annual
mass of emissions from each of these operations are summarized
in Table 2.
TABLE 2. EMISSION FACTORS AND ANNUAL MASS OF
EMISSIONS FROM PLASTICS PROCESSING
Hydrocarbons
Handling method
or process operation
Storage
Conveying
Dry blending
Hot roll mixing
Grinding
Adhesives production
Coating
Extrusion
Film and sheet
production
Foam generation
Lamination
Molding9
Emission
factor
(no control) ,
g/kg
25
55
48
20
120
41
20
Mass of
emissions ,
10 metric
tons/year
17
29
125
48
172
2.9
67
Particulates
Emission
factor
(no control) ,
g/kg
2.8
0.9
15
9
34
75
Mass of
emissions ,
10 ^ metric
tons/year
33
11
31
18
12
52
Particulate emissions were taken from data for thermosetting plastics; hydro-
carbon emissions were taken from data for both thermosetting plastics and
thermoplastics.
-------
Several evaluation parameters were used to determine the environ-
mental impact of atmospheric emissions from plastics processing.
The first parameter, source severity, S, relates the time-
averaged maximum ground level concentration, "
hazard factor, F, as follows:
,
x
to a health
S =
(1)
For this equation, Xmax is calculated according to Gaussian plume
dispersion theory, and F is defined as the primary ambient air
quality standard (AAQS) for criteria pollutants [hydrocarbons,a
particulates, sulfur oxides (SOX;/ nitrogen oxides (NOX), and
carbon monoxide (CO)]. For the purpose of determining source
severities, a representative plastics processing plant is defined
to be one which annually converts 3,330 metric tons of a particu-
lar resin into the appropriate distribution of products listed
in Table 1. Table 3 shows the source severity values for the 2
criteria pollutants, hydrocarbons and particulates, emitted from
16 representative plastic processing plants.
TABLE 3. SOURCE SEVERITIES FOR CRITERIA POLLUTANTS
EMITTED FROM 16 REPRESENTATIVE PLASTICS
PROCESSING PLANTS
Plastic type
Hydrocarbons
g/m
Particulates
g/m
Acrylic
Cellulosic
Epoxy
Nylon
Phenolic
Polyacetal
Polycarbonate
Polyester
High-density polyethylene
Low-density polyethylene
Polypropylene
Polystyrene & styrene copolymers
Polyur ethane
Polyvinyl chloride & copolymers
Reinforced thermoplastics
Urea and melamine
0.0023
0.0019
0.0034
0.0015
0.0027
0.0007
0.0023
0.0021
0.0012
0.0017
0.0024
0.0017
0.016
0.0028
0.0014
0.0022
14
12
21
9.5
14
4.2
14
13
7.7
11
15
10
98
17
9.0
14
0.00024
0.00024
0.00024
0.00024
0.0014
0.00024
0.00024
0.0028
0.00024
0.00024
0.00024
0.00024
0.00024
0.0015
0.00024
0.00063
0.94
0.94
0.94
0.94
5.5
0.94
0.94
11
0.94
0.94
0.94
0.94
0.94
5.8
0.94
2.4
There is no primary ambient air quality standard for hydro-
carbons. The EPA has published a recommended guideline for
meeting the primary ambient air quality standard for photochem-
ical oxidants.
-------
The second and third evaluation parameters relate the contribu-
tions of a specific pollutant from plastic processing plants to
the total emissions of that pollutant on a national and on a
state basis, respectively. In this regard, plastics processing
contributes 2.8% of the hydrocarbon emissions and 0.12% of the
particulate emissions nationwide. On a state basis, plastics
processing contributes from 0.04% to 8.96% of the hydrocarbon
emissions and from 0.00% to 2.59% of the particulate emissions,
depending on which state is considered.
The fourth evaluation parameter is an estimate of the number of
people exposed to the emissions from a representative plastics
processing plant. The population affected by the emissions from
plastics processing ranges from 11 persons to 326 persons for
hydrocarbons and from 2 persons to 46 persons for particulates.
The fifth evaluation parameter is an estimate of the increase in
the mass of emissions over the 5-yr period 1976 to 1981. The
mass of emissions from plastics processing in 1981 is expected to
be 54% greater than the 1976 value if no further implementation
of existing control technology occurs.
Control technology which is currently available and potentially
applicable to plastics processing plants can be divided into
controls for hydrocarbons and for particulates. Hydrocarbon con-
trol technology includes adsorption, absorption, incineration,
and condensation. Particulate control technology consists of wet
scrubbers, fabric filters, and mist eliminators.
-------
SECTION 3
SOURCE DESCRIPTION
SOURCE DEFINITION
Plastics processing is a type of polymer processing which in-
volves the use of various unit operations to mold, form, shape,
and otherwise alter plastic materials in order to increase their
utility. Bernhardt and McKelvey (1) have defined polymer proc-
essing as "...an engineering specialty concerned with operations
carried out on polymeric materials or systems to increase their
utility. These operations produce one or more of the following
effects: chemical reaction, flow, or a permanent change in a
physical property. Specifically excluded are the chemical
reactions involved in the manufacture of resins."
Types of Products
Plastics processing operations are performed in establishments
mainly engaged in molding primary plastics for the industry and
fabricating miscellaneous finished plastics products. Plants
that manufacture fabricated plastics products or plastics film,
sheet, rod, tube, nontextile monofilaments, and regenerated
cellulose products are included in this industry. The resins
used in these plants are either purchased or manufactured on
site. This industry, which includes establishments engaged in
compounding purchased resins, has been defined by the U.S.
Department of Commerce as "Miscellaneous Plastics Products" and
assigned Standard Industrial Classification 3079 (2).
Materials Processed
The materials handled in plastics processing plants include
thermoplastics, thermosetting resins, and foams. Each of 16
different resin types is discussed below. 1976 consumption and
processing data for these resins are presented in Appendix A.
(1) Bernhardt, E. C., and J. M. McKelvey. Polymer Processing-New
Engineering Specialty. Modern Plastics, 35 (10):44-45, 1958.
(2) 1972 Census of Manufactures, Volume II-Industry Statistics,
Part 2-SIC Major Groups 27-34. U.S. Department of Commerce,
Washington, D.C., August 1976. pp. 30A-1 through 30A-14.
-------
Acrylic Resins—
Acrylic resins are produced from methyl methacrylate, ethyl
acrylate, n-butyl acrylate, and isobutyl acrylate. The thermo-
plastic polymers are synthesized via radical chain polymeriza-
tion using an organic peroxide catalyst. The polymerization
reaction for poly (methyl methacrylate) is
H CH
I I
n C=C
catalyst —'
H C=O
A
"H CHS
1 1
Gf .
i_
H C=0
A
CH3
n
(2)
CH
Cellulosic Resins—
Cellulose acetate, cellulose butyrate, cellulose propionate,
cellulose nitrate, and cellulose triacetate are manufactured by
the esterification of cellulose, a natural polyhydric alcohol.
Cellulosic thermoplastics are not homogeneous because they con-
sist of a mixture of mono-, di-, and tri-substituted cellulose
esters (3).
In the synthesis of cellulosics, acids are used which correspond
to the cellulose derivative, i.e., acetic acid, butyric acid,
propionic acid, and nitric acid. The ester may be formed by
reaction of the acid anhydride or acid chloride with cellulose.
Sulfuric acid is also used in commercial practice as a catalyst
for the esterification (4) . To drive these reactions to comple-
tion, water must be removed, usually by azeotropic distillation.
Epoxy Resins--
Thermosetting epoxy resins are the reaction products of glycidyl
compounds and epoxidized olefins. Glycidyl compounds are pro-
duced by reacting epichlorohydrin with active hydrogen compounds
such as bisphenol A. Epoxidized olefins are produced by reacting
peracids or peroxides with either linear or cyclic olefin com-
pounds .
Epoxy resins are produced in unmodified and modified forms. Four
types of unmodified epoxy resins are manufactured: epichloro-
hydrin-bisphenol A resins, cycloaliphatic resins, novolac resins,
and phenoxy resins. Epichlorohydrin-bisphenol A resins account
(3) Ott E. Cellulose and Cellulose Derivatives. John Wiley and
Sons, Inc., New York, New York, 1955. 1601 pp.
(4) Travis, G. Cellulosic. Modern Plastics, 50(10A):34-36,
1973.
8
-------
for approximately 90% of the total consumption of epoxies (5).
By varying both the ratio of epichlorohydrin to bisphenol A and
the operating conditions, resins having the following general
structure are formed:
H
I
-c-4-o
H H
H H
H
(Epichlorohydrin-bisphenol A epoxy resin)
Uncured epoxy resins are crosslinked by either of two methods.
Direct crosslinking is initiated by a catalyst such as a terti-
ary amine or a boron trifluoride complex, or a combination of
these materials. Indirect crosslinking is achieved with harden-
ing agents such as polyf unctional amines or dibasic acid
anhydrides.
Nylon Resins —
Five common types of nylon resins are produced: nylon 6/6, nylon
6, nylon 6/10, nylon 6/12, nylon 11, and nylon 12. Thermoplastic
nylon 6/6 polymer is made from adipic acid and hexamethylene-
diamine (HMDA) as follows:
0 O
II II
HO-C-CH2CH2CH2CH2-C-OH
(Adipic acid)
H2N-CH2CH2CH2CH2CH2CH2
(Hexamethylenediamine)
0 O
rH3N-CH2CH2CH2CH2CH2CH2-NH3+][~O-C-CH2CH2CH2CH2-C-0"
(Hexamethylenediammonium adipate salt)
H HO O
I I II II
-N-CH2CH2CH2CH2CH2CH2-N-C-CH2CH2CH2CH2C-
(Nylon 6/6)
(3)
(5) Terry, H., and S. Nagy. System Analysis of Air Pollutant
Emissions from the Chemical/Plastics Industry. EPA-650/2-
74-106, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, October 1974. 281 pp.
-------
Nylon 6/6 derives its name from the six carbon atoms in adipic
acid and the six carbon atoms in HMDA (6).
Nylon 6 is synthesized from caprolactam, CH2(CH2)^NHCO. Nylon
6/10 polymer is made from hexamethylemediamine and sebacic acid,
HOOC (CH2)8COOH- Nylon 6/12 is made from HMDA and dodecanoic
acid, HOOC(CH2)ioCOOH. Nylon 11 is produced by self condensa-
tion of 11-aminoundecanoic acid, while Nylon 12 is produced by
self-condensation of laurolactam (6).
Phenolic Resins—
Phenolic resins are produced by polymerizing phenol, resorcinol,
or an alkyl-substituted phenol with formaldehyde (7). Curing
of the thermosetting resin requires either one or two stages,
depending on the curing agent used. Formaldehyde is used for
one-stage resins (8) which have a short shelf life because of
chemical instability. Hexamethylenetetramine ("hexa") is used
as the curing agent for two-stage resins, which are prepared by
reacting phenol with enough formaldehyde to produce a solid resin
that can be stored for long periods. "Hexa" is blended with the
solid resin prior to molding (8). About three-fourths of the
phenolic resins consumed consist of the two-stage type material
(9).
Polyacetal Resins--
Polyacetal resins are produced and consumed as homopolymers and
as copolymers. Acetal homopolymer is produced by polymerizing
formaldehyde to form a linear polyoxymethylene resin. The poly-
merization reaction is
H
I
n C=O
H
catalyst
H
!
C-O-h
I
H
n
(4)
where n equals 1,000 to 4,000 monomer units. The thermoplastic
polymer is stabilized either by capping its end groups with ace-
tic anhydrided, (CH3CO)2O, in the presence of an alkali acetate
catalyst, or by copolymerizing with ethylene oxide.
(6) Odian, G. Principles of Polymerization. McGraw-Hill Book
Company, New York, New York, 1970. 652 pp.
(7) Sherman, S. Epoxy. Modern Plastics, 50(10A):36-40, 1973.
(8) Hull, M. E. Phenolic. Modern Plastics, 50(10A):52-56, 1973.
(9) Martin, R. W. The Chemistry of Phenolic Resins. John Wiley
and Sons, Inc., New York, New York, 1956. 298 pp.
10
-------
Polycarbonate Resins—
Polycarbonate resins are thermoplastic polyesters of carbonic
acid having the following chemical structure:
O
li
-R-O-C-
n
Although R in the preceding structure may be either aliphatic or
aromatic, the only polycarbonate resin of current commercial
importance in produced from bisphenol A and phosgene, COC12.
Polyester Resins—
Unsaturated polyester resins are produced from maleic anhydride,
phthalic anhydride, and propylene glycol. Maleic anhydride,
phthalic anhydride and propylene glycol are combined in a mole
ratio of 1:2:3.15 to form the resin. Styrene is added to the
above mix until it comprises 35% of the total weight.
Reinforced materials are produced from unsaturated polyester
resins by the addition of glass fibers. Reinforced unsaturated
polyester resins are processed using special techniques in-
cluding lay-up (batch laminating), spray-up (spray painting of
resin and fiber glass), continuous laminating, filament winding,
matched die molding, injection molding, and centrifugal casting.
Polyethylene Resins—
Polyethylene resins are thermoplastics containing the following
repeating unit:
I
(
— v.
I
I H
: - c
{ i
-»
i
m
n
where n can vary from 350 to 140,000 monomer units, with a
typical range of 1,800 to 18,000. Polyethylene resins are
produced in three types:
Type of Polyethylene
Low density
Medium density
High density
Specific Gravity
0.925 and lower
0.926 to 0.940 (usually
included with low density)
0.941 and higher
11
-------
Low-density polyethylene (LDPE) and high-density polyethylene
(HOPE) have different molecular structures. They are manufac-
tured by different processes. LDPE is produced using high
pressure (70 MPa to 350 MPa) (5). HOPE is produced by a low
pressure (0.5 MPa to 3.0 MPa) process (5).
Polypropylene Resins—
Polypropylene resins are themoplastics containing the following
repeating unit:
~H H
-C-C -
I I
H CH3
n
Theoretically, polypropylene resins can exist in three isomeric
forms: atactic (amorphous), isotactic, and syndiotactic.
Approximately 90% to 95% of the commercial polypropylene resins
produced are in the isotactic form; 5% to 10% of those produced
are in the atactic form; and none are produced in the syndio-
tactic form. The atactic polypropylene resins are of lower
molecular weight than those in the isotactic form (personal
communications with I. O. Salyer and G. A. Richardson, Monsanto
Research Corporation, Dayton, Ohio, 18 July 1977).
Polystyrene and Styrene Copolymer Resins--
The styrene resins consist of general-purpose and impact poly-
styrenes. Styrene copolymer resins are those polymeric materials
which contain at least 45 weight percent styrene, although this
weight percent may span a broad range.
Polystyrene resins are obtained by the free-radical polymeriza-
tion of styrene monomer in the presence of an initiator such
as benzoyl peroxide. While polystyrene and styrene copolymer
resins (such as styrene-acrylonitrile and acrylonitrile-butadi-
ene-styrene) can be and have been manufactured by emulsion, mass,
solution or suspension techniques, suspension and continuous
solution polymerization are now the primary methods used in com-
mercial practice. Emulsion polymerization is still used in the
rubber and surface-coating resin industries; mass (bulk) poly-
merization has been phased out (personal communications with
D. Popielski, Monsanto Polymers and Petrochemicals Company, Port
Plastics, Cincinnati, Ohio and G. A. Richardson, Monsanto Research
Corporation, Dayton, Ohio, 19 July (1977).
General-purpose polystyrenes are glossy, crystal clear, high-
molecular-weight thermoplastic resins. Impact polystyrenes
contain polybutadiene to improve their impact strength.
12
-------
Although a typical styrene-acrylonitrile resin contains about 25
weight percent acrylonitrile, the amount can vary from 18% to 68%
(personal communications with D. Popielski, Monsanto Polymers and
Petrochemicals Company, Port Plastics, Cincinnati, Ohio, and
G. A. Richardson, Monsanto Research Corporation, Dayton, Ohio,
19 July 1977). Acrylonitrile-butadiene-styrene resins include a
number of materials that contain 50% or more styrene with varying
amounts of acrylonitrile and butadiene. These resins are two-
phase systems in which polybutadiene is dispersed in a rigid
styrene-acrylonitrile matrix.
Polyurethane Resins—
Polyurethanes are produced from polyhydroxy compounds and poly-
isocyanates according to the following chemical reaction:
HO OH
n O=C=N-R-N=C=0 + n HO-R '-OH -> —f-R-N-C-O-R' -0-C-N4—
n
(5)
where R and R1 may be aromatic or aliphatic hydrocarbon groups.
Flexible polyurethane foams—Flexible polyurethane foams are
based on toluene diisocyanate (TDI) and polyether polyols. The
TDI consists of an 80:20 mixture of 2,4-toluene diisocyanate and
2,6-toluene diisocyanate. Typical polyether polyols used are
polypropylene glycols and the propylene adduct of trimethylolpro-
pane. Propylene adducts of glycerin, 1,2,6-hexanetriol, and a
host of others are also used.
Rigid polyurethane foams—Rigid polyurethane foam is manu-
factured from di- or tri-functional isocyanates and di-, tri-,
tetra-, or higher-functionality polyols. The amounts of these
ingredients are varied depending upon the end-use requirements
and the physical characteristics of the foam. Density, uni-
formity, and compressive strength of the foam are all affected by
slight changes in the chemical composition.
Polyvinyl Chloride and Copolymer Resins—
Thermoplastic polyvinyl chloride resins are produced and consumed
as homopolymers and copolymers. The homopolymer is commercially
produced by polymerizing vinyl chloride in the presence of
initiators, such as peroxides and persulfate-redoxisystems, using
one of three basic processes: suspension, emulsion, and bulk
polymerization. The polymerization reaction is as follows:
H
Cl
n
C = C
I I
H H
(6)
Jn
where n can vary from 800 to 2,000 monomer units,
13
-------
Reinforced Thermoplastics—
Reinforced thermoplastics are manufactured by adding glass
fibers to commercially available resins such as nylon, polyacetal,
polycarbonate, polyester, polyethylene, polypropylene, and poly-
styrene and styrene copolymers. Reinforcement improves the
tensile strength, flexural modulus ("stiffness"), heat resistance,
and other mechanical properties of base thermoplastic resins.
Blending chopped glass fibers with a particular resin in an
extruder and passing continuous glass filaments through a polymer
melt tank yield "short glass" and "long glass" products, respec-
tively. Glass fiber loadings of 20% to 40% (by weight) are
typical of reinforced thermoplastics today (10).
Urea and Melamine Resins—
Amino resins are produced by reacting formaldehyde with
organic compounds such as urea (H2NCONH2) and melamine
(H2NCNC(NH2)NC(NH2)N) which contain more than one -NH2 functional
group. Curing of urea-formaldehyde and melamine-formaldehyde
resins involves further polymerization induced by acid catalysis
or the application of heat. These resins are usually processed
either as spray-dried powders or as aqueous or alcoholic solu-
tions (11). It is their solubility in water that makes the urea
and the melamine resins particularly suitable for the production
of adhesives and coatings.
Process Operations
The plastics processing industry employs essentially seven dif-
ferent process operations to manufacture finished products from
plastic resins and other new materials. The basic operating
principles of each of these seven processing methods are dis-
cussed below.
Adhesives Production—
An adhesive is defined as a substance capable of holding materi-
als together by surface attachment (12). Phenolic resins and
amino resins (urea-formaldehyde, melamine-formaldehyde) account
for 98% of the adhesives produced by the plastics processing
industry (13).
(10) Encyclopedia of Polymer Science and Technology, Vol. 12.
John Wiley and Sons, Inc., New York, New York, 1970. p. 32.
(11) O'Neill, C. T. Amino. Modern Plastics, 52(10A) :14-16,
1975.
(12) Encyclopedia of Polymer Science and Technology, Vol. 1.
John Wiley and Sons, Inc., New York, New York, 1964.
pp. 482-502.
(13) Plastics Sales Data, 1976 vs. 1975: Back Over the
13,000,000-Ton Mark. Modern Plastics, 54(l):49-52, 1977.
14
-------
Phenolic resins are made by acid- or base-catalyzed condensation
of phenol and formaldehyde, the ratio of these reactants ranging
from 1:0.8 to 1:1.5 (12). Phenolic plywood adhesives are basi-
cally solutions of low-molecular-weight resin in aqueous sodium
hydroxide. The adhesive for exterior-grade plywood is prepared
by mixing the following amounts of ingredients: phenol-formal-
dehyde, 25% to 30%; sodium hydroxide 2% to 4%; soluble dried beef
blood, 0% to 10%; fillers, such as oat-hull lignins, bark, or
wood flour, 10% to 25%; and water, 31% to 63% (12). In addition
to solvent dispersions, phenolic adhesives are available as
powders or tissue-backed glue films.
Liquid urea resin adhesives are produced by condensing 1 mol of
urea with 1.5 mol to 2 mol of aqueous formaldehyde in alkaline
solution (12). Fillers, catalysts, and buffering agents are
added to the resin before its end-use. Powdered urea resin
adhesives can be made by spray-drying.
Melamine-formaldehyde resins are synthesized by reacting one mole
of melamine with three moles of formaldehyde under slightly alka-
line conditions (12). Although melamine adhesives exhibit
superior resistance to water and heat, they are expensive and are
often diluted with urea resins.
Coating—
Six different methods of applying plastic coatings will be
briefly described here. A variation of another method, extrusion
coating, is used to produce plastic film and will be discussed in
Section 3.
Calender coating begins by squeezing the desired plastic between
heated rolls to form self-supporting sheets. The same set of
calender rolls is then used to press the plastic sheets against a
web of support material, thus bonding them to form the coated
product.
Dip coating is applicable to irregularly shaped objects such as
automotive parts, tool handles, and toys. Following complete
immersion in a tank of resinous solution, the coated articles are
drained and then dried for approximately 5 min in an oven heated
to 180°C to 200°C (14) as shown in Figure 1.
Metallic objects can be coated with liquid or powdered plastics
in the form of charged droplets generated by a specially con-
structed spray nozzle. Continuous webs of paper or textiles can
also be electrostatically coated by providing a grounded support
plate or roller to attract the charged plastic particles.
(14) Encyclopedia of Polymer Science and Technology, Vol. 3.
John Wiley and Sons, Inc., New York, New York, 1967.
pp. 765-830.
15
-------
Fluidized-bed coating has been used to apply cellulosic epoxy,
nylon, polyethylene, polyvinyl chloride, and other plastics to
individual articles or continuous webs. The object to be coated
is heated to a temperature above the melting point of the desired
resin, lowered into a fluidized bed of powder, and then removed
as a finished product.
The simplest mechanical device used for continuously spreading a
plastic coating onto flat surfaces is a knife, one application
of which is shown in Figure 2. The thickness of the coating is
directly determined by the separation between the knife edge and
the surface of the base material.
Reverse-roll coating can be adapted for use with a wide variety
of coating compositions, viscosities, and thicknesses. In this
process, depicted in Figure 3, a controlled amount of resin is
delivered from two metering and coating rolls to a third roll,
located below the first two, which "wipes" the coating onto a
web of support material.
•
Extrusion--
Extrusion is the process of shaping materials by forcing them
through a specially designed orifice under controlled conditions
(15). Thermoplastics are subjected to temperatures up to 330°C
and pressures up to 35,000 kPa in an extruder in order to pro-
duce a polymer melt capable of flow through the orifice (16).
After mixing, granular or powdered resin and colorants, fillers,
stabilizers, and other additives are fed to the machine through
a conical hopper, as shown in Figure 4 (17). These raw mate-
rials are usually preheated to prevent the formation of bubbles
(by driving off volatile constituents) and to prevent hydrolysis
of the resin (by evaporating any residual moisture in the feed).
One or more screws rotating inside the extruder barrel carry the
cold, bulky feed material forward to the compression zone, where
the plastic is melted to uniform consistency by the action of
viscous drag. In the so-called metering zone, sufficient pres-
sure is developed to force the molten plastic through the orifice
or "die," at a constant flow rate.
(15) Envyclopedia of Polymer Science and Technology, Vol. 6.
John Wiley and Sons, Inc., New York, New York, 1967.
pp. 466-467.
(16) Plastics Engineering Handbook of The Society of the Plastics
Industry, Inc., Third Edition. A. F. Randolph, ed. Rein-
hold Publishing Corporation, New York, New York, 1960.
565 pp.
(17) Encyclopedia of Polymer Science and Technology, Vol. 8.
John Wiley and Sons, Inc., New York, New York, 1968.
p. 555.
16
-------
EXHAUST HOOD
PREHEAT OVEN
FUSING OVEN
o b lob o ft lob o
fy (y (&/
WATER - COOLED
PLASTISOL DIP TANK
Figure 1. Dip-coating line (14)
I— COAT ING KNIFE
COATING
COMPOUND
BACKING ROLL
Figure 2. Knife-over-roll coating (14)
METERING ROLL
ELASTOMERICROLL
Figure 3. Reverse-roll coating (14).
17
-------
ADAPTER
£"^
/
//#/t
DRIVE MOTOR-
Figure 4. A typical single-stage, single-screw
extruder for plastics (17).
The extruded product is then transported over rollers, a conveyor
belt, or other take-off equipment to facilities for cooling the
hot plastic by air or liquid. Automatic cutting and winding
devices are available for final product preparation.
Film and Sheet Production—
Melt extrusion, using flat or circular dies, and solvent casting
are the most commonly used methods of film manufacture. Sheeting
is produced by extrusion or in-situ polymerization.
Thermoplastic linear polymers, such as polyethylene and polyvinyl
chloride, can be extruded using a slot die which is approximately
as wide as the finished film and about 10 to 40 times the thick-
ness (18). Typical melt-extrusion temperatures range between
160°C and 300°C (18). After the flat film exits from the rectan-
gular die, it is cooled by a liquid bath or chilled rotating rolls
before final trimming and windup (Figure 5). This particular film
manufacturing process is used only by a few large-volume producers
(19) .
(18) Encyclopedia of Polymer Science and Technology, Vol. 6. John
Wiley and Sons, Inc., New York, New York, 1967. pp. 764-775.
(19) Hager, J. E. Polyethylene Film and Sheet. Modern Plastics,
52(10A):138, 1975.
18
-------
•EXTRUDER
COOLING ROLL
WIND -UP
Figure 5. Production of plastic film by slot-die extrusion (18)
NIP ROLLS
FLATTENING ROLLS
BLOWN
TUBE
AIR INLET
AIR RING
EXTRUDER
SCREEN PACK
BREAKER PLATE
Figure 6.
Production of plastic film by
circular-die extrusion (18).
19
-------
Melt extrusion using a circular die produces on inflated tube of
hot plastic rather than a flat sheet. This "bubble" is air-
cooled externally, collapsed by nip rolls, and then wound as is
(Figure 6) or after being slit longitudinally to yield a film of
greater width.
Solvent casting is accomplished by extruding a solution of resin
and additives onto rotating drums or endless belts. Film is
formed by carefully evaporating the solvent in large, multizoned
ovens. These ovens are often equipped with vapor recovery sys-
tems to minimize solvent losses (20).
Sheets may be manufactured by in-situ batch polymerization of
reactive monomers such as methyl methacrylate, the starting
material for the most common acrylic plastic. Two pieces of
heat-resistant glass separated by a peripheral gasket serve as
the mold for a single plastic sheet. Curing temperatures for
molded sheet may be as high as 93°C (21).
Foam Generation--
An example of this process operation is the production qf poly-
urethane foam, which accounts for 70% of all foams manufactured
by the plastics processing industry (13). Polyurethane foam is
formed by catalytic reaction of a polyfunctional isocyanate and a
polyhydroxy compound. The blowing agent for flexible foams is
carbon dioxide, generally in-situ by the reaction of isocyanate
and water. For rigid foams, blowing is enhanced by using vola-
tile liquids, usually halogenated hydrocarbons such as dichloro-
difluoromethane, which vaporize upon heating of the reaction
mixture.
In practice, polyurethane foams are produced by either of two
general types of processes: the "one-shot" method, in which all
the required ingredients are mixed and discharged onto a suitable
surface for expansion; and the "prepolymer" process, wherein the
polyhydroxy compound is reacted with sufficient polyisocyanate to
form a prepolymer with isocyanate end groups. The prepolymer
mixture, containing excess isocyanate, is treated with water and
the appropriate catalyst, resulting in simultaneous expansion and
crosslinking of the foam.
Preparation of commercial foam slabstock begins by dispensing
overlapping parallel lines of the mixed reactants described above
onto a continuously moving paper web. This method is used
because the usual methods of mixing raw materials may lead to
temperatures as high as 170°C in the expanding foam from the heat
(20) Smith, D. E. Casting of PVC Film. Modern Plastics,
52(10A):266, 1975.
(21) Gambina, H. J., Jr. Casting of Acrylics. Modern Plastics,
52(10A):263-264, 1975.
20
-------
of reaction (22). After the paper backing is removed, the raw
polyurethane foam slab or "bun" is treated with steam or radiant
heat in an oven to .cure the surface. The foam "bun" is then cut
into blocks of standard lengths, and these are transported to a
storage room for cooling.
Lamination—Laminates are plastic products consisting of multiple
layers of reinforcing materials which have been coated with a
resinous binder and then fused into rigid sheets by the applica-
tion of heat and pressure. All thermosetting plastics are suita-
ble as laminating binders, but phenolics are the most commonly
used.
Commercial production of laminated plastics involves three basic
operations: impregnation, drying, and pressing. The synthetic
resin is dissolved in open kettles to form a "varnish" containing
the resin, an appropriate solvent, and various chemical additives.
The base material, a web of either paper or fabric, is continu-
ously impregnated with the resin solution by passing it through a
shallow dip tank.
After excess laminating varnish is removed by scraper blades or
squeeze rolls, the coated web is drawn through an air-heated oven
to vaporize the solvent and increase the average molecular weight
of the resin by further reaction (see Figure 7). The temperature
© FAN
I ill HEAT COIL
Illl FILTER
MAIN EXHAUST
COOL EXHAUST COOL AIR
©
PLANT AIR
RAW PAPER
IMPREGNATING
BATH
STACKER
ZONE I
SOLVENT
EVAPORATION
ZONE II
RESIN
ADVANCEMENT
ZONE 111
COOLING
Figure 7. Schematic diagram of impregnation and drying
operations in laminated plastics production.
(22) Encyclopedia of Polymer Science and Technology, Vol. 15.
John Wiley and Sons, Inc., New York, New York, 1971. pp.
pp. 445-479.
(23) Encyclopedia of Polymer Science and Technology, Vol. 8.
John Wiley and Sons, Inc., New York, New York, 1968.
pp. 121-148.
21
-------
of the oven at the web inlet is maintained at 110°C to 120°C to
evaporate the solvent (23). Venting the oven to the atmosphere
causes emission of hydrocarbons, including the solvent and vola-
tile resin constituents.
The dried web is next cut into pieces of appropriate length by
rotary knives. Several pieces of different impregnated base
materials can be arranged in any desired order to form a compos-
ite sheet. A number of such sheets, separated by steel plates,
are simultaneously converted into laminates by compaction in a
hydraulic press at pressures of 1,400 kPa to 12,000 kPa and
temperatures of 140°C to 180°C (24). Total curing time ranges
from 45 min to 4 hr, depending on the resin used and the thick-
ness of the laminated sheet (24).
Molding—
Plastic objects of almost any desired shape can be produced com-
mercially by five different types of molding processes: blow,
compression, injection, rotational, and transfer (25).
Blow molding is used to produce bottles and other hollow articles
from thermoplastic resins. A tube or "parison" of softened
plastic is inserted into a two-part cavity mold. Air at pres-
sures of 170 kPa to 690 kPa is used to expand the parison against
the cool mold surfaces, where the plastic hardens into shape
(25).
In compression molding, a measured quantity of thermosetting
plastic is placed into the bottom half of an open mold which is
heated to approximately 150°C (25). A hydraulic press brings the
mold halves together, and the hot plastic is formed to the shape
of the mold. A compression mold may be opened briefly at a
predetermined time to release gaseous byproducts formed during
the polymerization of some thermosetting compounds.
An injection-molding machine (Figure 8) fuses powdered or granu-
lar thermoplastics with heat and pressure and forces the molten
mass into a cool chamber for solidification. Scrap plastic, left
in the feed channels to the mold cavity after injection, is
usually ground and reused as feed material.
Rotational molding is used to make hollow objects from powdered
polyolefin plastics. A mold charged with a predetermined weight
of plastic is placed in an oven at 205°C to 480°C and rotated
(24) Muller, G. J. Industrial Laminates. Modern Plastics,
52 (10A) :152-158, 1975.
(25) Encyclopedia of Polymer Science and Technology, Vol. 9
John Wiley and Sons, Inc., New York, New York, 1968.
op. 1-157.
22
-------
MOLD -CLAMP CYCLINDER
TORPEDO SPREADER^
BOOSTER RAM
r |i MATERIAL
PCYCLINDER
MOLD - CLAMP RAM HEATING ELEMENTS
^MOVABLE DIE HEAD*-
FEED CHUTE
-jinnnni
INJECTION RAM
NOZZLE
KNOCKOUT BAR
DIE HEAD RAM
\INJECTION
PLUNGER
CONTROL STATION
INJECTION
PRESSURE
ADJUSTMENT
CLAMP
PRESSURE
GAGE
r
1
O
SUCTION
/PREFILL
jf VALVE
! °
/FEED ROD INJECTION
/' CYCLINDER
f n
INJECTION PRESSURE GAGE
-TEMPERATURE GAGE
OIL RESERVOIR
Figure 8. Schematic diagram of a plunger-type
injection-molding machine (25).
around two perpendicular axes simultaneously (25). After the
molten plastic has covered and become fused to the mold surfaces,
the mold is chilled, and the product removed.
Transfer molding, shown in Figure 9, is a method of producing
solid objects from thermosetting resins, much like compression
molding. A "plunger" forces presoftened plastic through a small
opening into a heated mold cavity, where final curing occurs.
Physical properties of transfer-molded parts can often be
improved by postcuring at elevated temperatures following removal
from the mold.
GEOGRAPHICAL DISTRIBUTION
In 1972, plastics processing was performed in 7,698 plants in the
United States according to the Census of Manufactures (2). These
establishments are mostly located in highly populated, metro-
politan areas. Table 4 presents the geographical distribution of
plant sites and the 1976 consumption of plastics for processing.
In those states in which an estimate of the number of plastic
processing plants is listed, the known number of unspecified
plant sites within a given geographic region was allocated in
proportion to the populations of the states in that region (2,
26). Individual state consumptions were calculated primarily
from the appropriate fractions of the total value of industry
(26) The World Almanac and Book of Facts 1976. G. E. Delury, ed.
Newspaper Enterprise Association, Inc., New York, New York,
1975. 984 pp.
23
-------
TRANSFER POT PLUNGER
MOLDING MATERIAL
EJECTOR PIN
a)
RUNNERS
MOLDED PART
(b
Figure 9. Basic transfer mold operation.
(a) Transfer mold closed, pot loaded; (b) transfer mold closed;
(c) transfer mold open; mold part, cull, and runners ejected (25)
24
-------
TABLE 4. GEOGRAPHICAL DISTRIBUTION OF PLASTICS PROCESSING (2)
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Lndiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
TOTAL
Average plant
Number
of plants
46
3a
49
41
1,084
63
154
27
292
llia
11
581
208
57
77
50
33
16
65
378
378
416
174
30
7a
23
5a
38
558
17
785
126
8a
546
60
53
384
72
52
8
104
322
32
16
53
101
17
"I-
7,698
capacity
Estimated consumption,
10' metric tons/yr
151
1
39
45
1,210
27
159
86
182
125
3
5
896
494
163
100
164
36
63
104
537
537
605
203
84
210
3
35
2
83
930
7
894
284
10
1,370
65
29
684
169
166
10
332
448
14
35
293
58
10
273
2
11,900
1.55
Estimated.
25
-------
shipments (2), additional input being derived from the distribu-
tion of plant sites. The census data indicate that 10 states
(California, Illinois, Indiana, Massachusetts, New Jersey, New
York, Ohio, Pennsylvania, and Texas) account for over 67% of the
plastics processing capacity. Figure 10 illustrates the geo-
graphical distribution of plastics processing plants.
>500
301 to 500
101 to 300
51 to 100
<50
Figuz-e 10. Geographical distribution of
plastics processing plants.
26
-------
SECTION 4
EMISSIONS
SELECTED POLLUTANTS AND THEIR CHARACTERISTICS
The materials emitted from plastics processing plants are:
particulates, consisting of resin powders, solid additives, and
hydrocarbon aerosols; and hydrocarbons, consisting of blowing
agents, monomers, dimers, solvents, and additives such as plasti-
cizers, lubricants, flame retardants, antioxidants, ultraviolet
absorbers, catalysts, stabilizers, and fillers. Particulates and
hydrocarbons were selected for study due to their adverse health
effects and atmospheric reactivity. Sulfur oxides, nitrogen
oxides, and carbon monoxide were not studied because they are not
emitted from plastics processing operations.
The primary AAQS, health effects, and atmospheric reactivities
of emissions from plastics processing are the same as those for
similar emissions from other air pollution sources. Particulate
emissions from plastics processing are composed of solid and
liquid aerosols. The solid particulates are generated during
grinding, cutting, sawing, and pneumatic conveying of polymeric
materials. Hydrocarbon emissions from plastics processing are
the result of one or more of the seven previously described
process operations performed by this industry--adhesives produc-
tion, coating, extrusion, film and sheet production, foam genera-
tion, lamination, and molding.
EMISSION FACTORS
The quantities of emissions produced per unit of material pro-
cessed (i.e., emission factors) are presented in Table 5. These
data, given for each plastic type and for each handling method or
process operation, represent total uncontrolled emissions of
hydrocarbons or particulates, no specification being made as to
the composition of the materials emitted. Table 5, a compilation
of information gathered from the literature and from a National
Emissions Data System (NEDS) Point Source Listing,3 includes only
Point Source Listings are provided by EPA from the NEDS via the
Aerometric and Emissions Reporting System (AEROS) (27).
(27) Aerometric and Emissions Reporting System (AEROS), U.S.
Environmental Protection Agency, National Air Data Branch,
Research Triangle Park, North Carolina.
27
-------
those data sources which contain emission factors or data that
can be used to calculate such factors. The accuracy of the data
contained in the table is unknown. (Blanks in the table indicate
that particular data are not reported in the cited references.)
The emission factor cited in Section 2 for plastic film and sheet
production (20 g/kg) was calculated by averaging the values given
at the bottom of Table 5 for film production (21 g/kg) and for
sheet production (7 g/kg). This average emission factor was
weighted according to the quantities of plastics known to be used
in 1976 for film only (1,684 metric tons) and for sheet only
(135 metric tons), 87.4% of the former having been for low-
density polyethylene film (13).
TABLE 5. TOTAL HYDROCARBON AND TOTAL PARTICULATE EMISSION
FACTORS FOR PLASTICS PROCESSINGS•b
(g/kg)
Handling method Process operation
Dry Hot roll
_ _ Plastic type Storage Conveying blending ___mixin£ Grinding Adhesives Coating Extrusion Film Sheet Foam Laminates_ Molding
Acrylic - - - -
Cellulosic
Epoxy
Nylon - - - - - H;15
Phenolic - - P;16 H;25C - - - - H;7
to 60
Polyacetal - - - - - - - H;1.5
Polycarbonate - - - - __ _ -H,32
Polyester - - - -H,28H;20
to 53
High-density polyethylene - - - - H,5.5 - -
Low-density polyethylene - - H;33 H,33 - -
Polypropylene - - - - -
Polystyrene and - - - - - H;20 - H;l
styrene copolymers to 40C
Polyurethane - H;25° H;1 H;14
to 420
olyvinyl chloride P,l P,9 P;40 - H;35 H; 20 H;6 H;3
and copolymers to 30 to 75 to 90 to 24 to 10
Urea and melamine
Emission factors not P.1.5 P,0.7
specified by polymer to 4 to 1.2
H,21 H,7 H;120 H,41 H,20
P;75
n, designate lowest and highest values. All factors represent uncontrolled emissions.
oro Reference 27 unless otherwise noted.
28
-------
DEFINITION OF A REPRESENTATIVE SOURCE
Representative sources of emissions from plastics processing were
defined for use in determining the source severity described in
Section 4. A representative source is any plant which annually
converts 3,330 metric tons of any one type of raw plastic into
finished products. This production rate was chosen because it
equals the mean production rate for the 3,300 plastic processing
plants which employ 20 or more people (2) . Note that these 3,300
plants account for more than 90% of the total domestic plastics
processing capacity (2) .
A total of 16 representative plastics processing plants is needed
in that 16 different resins (low-density polyethylene, polyvinyl
chloride, polyurethane, etc.) are processed in quantities greater
than 25,000 metric tons/yr in the United States. Each of these
16 plants is assumed to practice the appropriate distribution of
process operations for its particular plastic type, as given in
Table 1 of Section 2.
Emissions from plastics processing equipment are assumed to be
collected by plant ventilation and released to the atmosphere
from the top of a two-story building at a height of 6.1 m. The
following additional assumptions were made to characterize the
representative plastics processing sources: wind speed equals
the national average of 4.5 m/s; meteorological conditions cor-
respond to atmospheric stability Class C; and population density
surrounding each plant is 100 persons/km2 , which equals the
population density for the state with the largest capacity; i.e.,
Ohio.
SOURCE SEVERITY
Maximum Ground Level Concentration
The maximum ground level concentration, Xmax' °f each criteria
pollutant resulting from plastics processing for each representa-
tive source was estimated using Gaussian plume dispersion theory.
Detailed derivations of all source severity equations are given
in Appendix B. Xmax values were calculated using the formula
(7)
eu
where Q = mass emission rate, grams per second
u = average wind speed, meters per second
h = average emission height, meters
e = 2.72
Values of maximum ground level concentrations of hydrocarbons and
particulates are shown in Table 6 for the respresentative sources.
29
-------
TABLE 6. MAXIMUM GROUND LEVEL CONCENTRATIONS FOR
MATERIALS EMITTED FROM PLASTICS PROCESSING
Maximum ground level concentration,
Xmax'
Plastic type
Acrylic
Cellulosic
Epoxy
Nylon
Phenolic
Polyacetal
Polycarbonate
Polyester
High-density polyethylene
Low-density polyethylene
Polypropylene
Polystyrene and styrene copolymers
Polyurethane
Polyvinyl chloride and copolymers
Reinforced thermoplastics
Urea and melamine
Hydrocarbons
0.0045
0.0038
0.0068
0.0031
0.0044
0.0014
0.0045
0.0043
0.0025
0.0034
0.0047
0.0033
0.032
0.0056
0.0029
0.0044
Particulates
0.00070
0.00070
0.00070
0.00070
0.0041
0.00070
0.00070
0.0081
0.00070
0.00070
0.00070
0.00070
0.00070
0.0043
0.00070
0.0018
Severity Factor
To obtain an indication of the hazard potential of the represent-
ative sources, a severity factor, S, was defined as
S =
X
max
(8)
where
and F =
/t \° ' 17
v = v I —
Amax Amax\t
primary ambient air quality standard for criteria
pollutants, 1.6 x 10~4 g/m3 for hydrocarbons3 and
2.6 x I0~^ g/m3 for particulates
(9)
t = "short-term" averaging time, 3 min
time-averaging period for criteria pollutants, 3 hr for
hydrocarbons and 24 hr for pollutants
There is no primary ambient air quality standard for hydro-
carbons. The EPA has published a recommended guideline for
meeting the primary ambient air quality standard for photo-
chemical oxidants.
30
-------
The severity factor represents the ratio of time-averaged maximum
ground level exposure> Xroax' to the hazard level of exposure for
a particular emission. Ymax ^s *-ne maximum ground level concen-
tration, )(max/ averaged over a given period of time. For cri-
teria pollutants, averaging times are the same as those used in
the primary ambient air quality standards.
The severity factors for each emission from each representative
source are shown in Table 7. It can be seen that the severity
factor for hydrocarbons is greater than 1.0 for all 16 plastic
types. The severity factors for particulates from phenolic,
polyester, polyvinyl chloride, and urea and melamine plastics are
also greater than 1.0; all other particulate severity factors are
between 0.1 and 1.0.
TABLE 7. SOURCE SEVERITIES FOR PLASTICS PROCESSING
Source severity, S
Plastic type Hydrocarbons Particulates
Acrylic
Cellulosic
Epoxy
Nylon
Phenolic
Polyacetal
Polycarbonate
Polyester
High-density polyethylene
Low-density polyethylene
Polypropylene
Polystyrene and styrene copolymers
Polyurethane
Polyvinyl chloride and copolymers
Reinforced thermoplastics
Urea and melamine
14
12
21
9.5
14
4.2
14
13
7.7
11
15
10
98
17
9.0
14
0.94
0.94
0.94
0.94
5.5
0.94
0.94
11
0.94
0.94
0.94
0.94
0.94
5.8
0.94
2.4
Mass of Criteria Pollutant Emissions
The annual mass of emissions from each plastic type and each pro-
cess operation was obtained by multiplying the appropriate emis-
sion factor (Table 5, Section 4) by the consumption of plastics.
for each process operation (Tables A-l through A-15, Appendix A).
If no specific emission factor is given in Table 5 for a plastic
type undergoing a certain process operation, the average value
for that process operation was used. The entire quantity of
every plastic type was assumed to be handled through both storage
and conveying. It was also assumed that 3% of the total amount
of every plastic type, in the form of defective and otherwise
rejected products, was subject to grinding (for subsequent use as
31
-------
recycled plastic). The masses of hydrocarbon and particulate
emissions from plastics processing, thuse calculated, are pre-
sented in Tables 8 and 9, respectively.
Table 10 gives the ratios of criteria pollutant emissions result-
ing from plastics processing to the total criteria pollutant
emissions from all stationary sources in each state and in the
entire nation. These percentages were calculated using data from
Reference 28 and Tables 4, 8, and 9 of this report. On a nation-
wide basis, the emissions from plastics processing constitute
2.79% of the hydrocarbon emissions and 0.12% of the particulate
emissions from stationary sources.
Population Exposed to High Pollutant Concentrations
To obtain a quantitative evaluation of the population influenced
by a high concentration of emissions resulting from plastics pro-
cessing, the_area exposed_to the time-averaged ground level con-
centration, x» f°r which x/F is greater than _! was obtained by
determining the area within the isopleth for x- Tne number of
people within the exposed area was then calculated by using the
representative population density (100 persons/km2) suggested in
Section 4. A detailed explanation of the calculation of affected
population is presented in Appendix B.
For each of the two criteria pollutants (i.e., hydrocarbons and
particulates) emitted from the 16 representative plastics process-
ing plants, the populations exposed to a time-averaged ground
level concentration for which x/F is greater than or equal to 1
are shown in Table 11. Additional input data and output from the
affected population calculations are tabulated in Appendix C. It
should be noted that although hydrocarbon emissions from poly-
urethane processing have the largest severity in the entire
plastics industry (Table 7), these emissions affect only 326
persons (Table C-l). The limited impact in human health of a
source with a low emission height (e.g., 6.1 m for plastic proc-
essing) is the result of pollutants being dispersed over a very
small area in the immediate vicinity of the source.
32
-------
TABLE 8. NATIONAL MASSES OF HYDROCARBON EMISSIONS
FROM PLASTICS PROCESSING
(103 metric tons/yr)
Plastic type Adhesives
Acrylic
Cellulosic
Epoxy 0.23
Nylon
Phenolic 8.7
Polyacetal
Polycarbonate
Polyester
High-density polyethylene
Low-density polyethylene
Polypropylene
Polystyrene and styrene copolymers
Polyurethane 0.02
Polyvinyl chloride and copolymers
Reinforced thermoplastics
Urea and melamine 8.1
PROCESS OPERATION TOTALS 17
Coating Extrusion
3.4 2.
Q.
3.2 0.
0.
0.67
0.
0.33 10.
1.
14.
20.
13.8 23.
0.28 0.
3.2 50.
4.0
29 125
.0
.59
.49
.72
.29
.3
,2
.9
.9
.7
.00
.2
cess operation
Film Sheet Foam Laminates
0.53
0.50 0.14
0.10 0.01 0.33
0.11 0.08
1.9
0.02
0.02
0.17 0.01
0.84 0.49
34.2
1.9
9.0
0.02 0.00 160
8.1 1.2 2.7 0.69
46 2.5 172 2.9
Total hydrocarbon
Molding
0
0
0
0
6
0
1
9
18
6
9
1
0
10
1
0
67
.82
.55
.16
.90
.1
.04
.5
.2
.4
.1
.5
.1
.12
.4
.3
.84
emissions for
plastic type
6
1
4
1
17
0
1
20
21
55
32
47
161
76
1
12
462
.8
.8
.6
.8
.4
.36
.6
.1
.0
.1
.2
.7
.5
.3
.9
a
Note.—Blanks indicate no emissions present.
The 462,000 metric tons/yr of hydrocarbon emissions from the plastics processing industry represent 2.8% of the total U.S.
hydrocarbon emissions from all stationary sources (28).
(28) Eimutis, E. C., and R. P. Quill. Source Assessment: State-by-State Listing of Criteria Pollutant Emissions. EPA-600/
2-77-107b, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, July 1977. 138 pp.
TABLE 9. NATIONAL MASSES OF PARTICULATE EMISSIONS
FROM PLASTICS PROCESSING
(103 metric tons/yr)
Handling Method
Plastic type
Acrylic
Cellulosic
Epoxy
Nylon
Phenolic
Polyacetal
Polycarbonate
Polyester
High-density polyethylene
Low-density polyethylene
Polypropylene
Polystyrene and styrene copolymers
Polyurethane
Polyvinyl chloride and copolymers
Reinforced thermoplastics
Urea and melamine
PROCESS OPERATION TOTALS
Storage
0
0
0
0
1
0
0
1
3
6
2
5
2
5
0
1
33
.61
.19
.28
.24
.6
.11
.14
.9
.4
.6
.8
.8
.1
.6
.19
.2
Dry
Conveying blending
0.
0.
0.
0.
0.
0.
0.
0.
1.
2.
1,
2.
0.
1.
0
0.
11
.21
.07
,10
,08
,56
.04
.05
.66
.2
.3
.0
,0
.72
.9 31.4
.07
42
31
Total particulate
Hot roll
mixing Grinding Molding
0.
0.
0.
0.
0.
0,
0.
0
1.
2.
1.
2.
0
18.3 2
0
0.
18 12
.22
.07
,10
.09
.60 13.7
.04
.05
.70 34.7
.3
.4
.0
.1
.76
.0
.07
.44 3.2
52
emissions for
plastic type
1.
0.
0.
0.
16.
0.
0.
37.
5.
11.
4.
9.
3.
59.
0.
5.
157d
0
33
47
41
5
18
24
9
9
3
7
9
5
3
32
3
Note.—Blanks indicate no emissions present.
3The 157,000 metric tons/yr of particulate emissions from the plastics processing industry represent 0.12%
of the total U.S. particulate emissions from all stationary sources (28).
33
-------
TABLE 10. STATE MASSES OF EMISSIONS FROM PLASTICS PROCESSING
Hydrocarbons
State hydrocarbon
emission rate,
State 10 3 metric tons/yr
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
5.9
0.04
1.5
1.7
47
1.1
6.2
3.3
7.1
4.8
0.11
0.18
35
19
6.3
3.9
6.4
1.4
2.5
4.1
21
23
7.9
3.3
8.1
0.11
1.4
0.07
3.2
36
0.29
35
11
0.40
53
2.5
1.1
27
6.5
6.5
0.40
13
17
0.54
1.3
11
2.3
0.39
11
0.04
Particulates
Percent of
state's total State particulate
hydrocarbon emission rate,
emissions 10 3 metric tons/yr
2.59
0.11
1.53
1.28
3.30
0.72
2.98
5.06
1.66
1.50
0.21
0.32
4.20
4.56
3.38
1.62
2.78
0.14
4.30
1.66
5.66
4.37
3.14
1.56
2.63
0.13
1.34
0.31
8.67
5.69
0.25
3.16
3.24
1.00
6.34
1.05
0.72
2.94
8.96
3.66
1.11
5.00
0.80
0.78
6.36
4.20
0.87
0.24
3.78
0.04
2.0
0.01
0.51
0.59
16
0.36
2.1
1.1
2.4
1.6
0.04
0.06
12
6.5
2.2
1.3
2.2
0.48
0.84
1.4
7.1
8.0
2.7
1.1
2.8
0.04
0.47
0.02
1.1
12
0.10
12
3.8
0.14
18
0.86
0.38
9.0
2.2
2.2
0.14
4.4
5.9
0.19
0.46
3.9
0.77
0.13
3.6
0.01
Percent of
state's total
particulate
emissions
0.09
0.00
0.02
0.04
0.27
0.01
0.66
0.80
0.10
0.08
0.02
0.00
0.38
0.29
0.10
0.04
0.13
0.03
0.08
0.18
1.28
0.29
0.09
0.07
0.09
0.00
0.02
0.00
0.35
1.79
0.00
0.44
0.18
0.00
0.57
0.04
0.01
0.28
2.59
0.19
0.00
0.25
0.06
0.01
0.16
0.25
0.03
0.01
0.16
0.00
NATIONAL TOTALS
462
2.79
157
0.12
34
-------
TABLE 11. POPULATIONS EXPOSED TO PLASTICS PROCESSING
EMISSIONS FOR WHICH x/F > 1
Affected population, persons
Pollutant
Plastic type Hydrocarbons Particulates
Acrylic 41 2
Cellulosic 34 2
Epoxy 64 2
Nylon 27 2
Phenolic 40 22
Polyacetal 11 2
Polycarbonate 41 2
Polyester 39 46
High-density polyethylene 21 2
Low-density polyethylene 30 2
Polypropylene 43 2
Polystyrene and sytrene copolymers 30 2
Polyurethane 326 2
Polyvinyl chloride and copolymers 52 23
Reinforced thermoplastics 25 2
Urea and melamine 40 8
35
-------
SECTION 5
CONTROL TECHNOLOGY
Emissions from the plastics processing industry consist of hydro-
carbons and particulates. Control technology potentially applic-
able to each of these two criteria pollutants is described below.
HYDROCARBONS
Adsorption
Adsorption is the process for removing molecules from a fluid by
contacting them with a solid. Gases, liquids, or solids can be
selectively removed from air streams with materials known as
adsorbents. The material which adheres to the adsorbent is
called the adsorbate (29).
The mechanism by which components are adsorbed is complex, and
although adsorption occurs at all solid interfaces, it is minimal
unless the adsorbent has a large surface area, is porous, and
possesses capillaries. The important characteristics of solid
adsorbents are their large surface-to-volume ratio and their pre-
ferential affinity for individual components (29).
Adsorption is a three-step process. The adsorbent is first con-
tacted with the fluid, and adsorption results. Second, the unad-
sorbed portion of the fluid is separated from the adsorbent. For
gases, this operation is completed when the gases leave the
adsorbent bed. Third, the adsorbent is regenerated by removal of
the adsorbate. Low pressure steam is used to regenerate the
adsorbent, and the condensed vapors are separated from the water
by decantation, distillation, or both (29).
Activated carbon is capable of adsorbing 95% to 98% of the
organic vapor from air at ambient temperature in the presence of
(29) Hughes, T. W., D. A. Horn, C. W. Sandy, and R. W. Serth.
Source Assessment: Prioritization of Air Pollution from
Industrial Surface Coating Operations. EPA-650/2-75-019-a,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, February 1975. 302 pp.
36
-------
water in the gas stream (30). Because the adsorbed compounds
have low vapor pressure, at ambient temperatures, the recovery of
organic materials present in air in small concentrations is low.
The adsorption system can be operated without hazard because the
vapor concentration is below the flammable range (29).
When an organic vapor in air mixture starts to pass over acti-
vated carbon, complete adsorption of the organic vapor takes
place. As the adsorptive capacity of the activated carbon is
approached, traces of vapor appear in the exit air, indicating
that the breakpoint of the activated carbon has been reached. As
the air flow is continued and although additional amounts of
organic materials are adsorbed, the concentration of organic
vapor in the exit air continues to increase until it equals that
in the inlet air. The adsorbent is saturated under these operat-
ing conditions (29).
The adsorption of a mixture of adsorbable organic vapors in air
is not uniform. The more easily adsorbed components are those
with the higher boiling points. When air containing a mixture of
organic vapors is passed over activated carbon, the vapors are
equally adsorbed at the start. However, as the amount of the
higher boiling component in the adsorbent increases, the more
volatile component revaporizes. The exit vapor consists primar-
ily of the more volatile component after the breakpoint has been
reached. This process continues for each organic mixture compo-
nent, until the highest boiling component is present in the exit
gas. In the control of organic vapor mixtures, the adsorption
cycle should be stopped when the first breakpoint occurs as
determined by detection of vapors in the exit gas. Many theories
have been advanced to explain the selective adsorption of certain
vapors or gases. These theories are presented in Perry and
Chilton (31) and will not be discussed here.
The quantities of organic vapors adsorbed by activated carbon are
a function of the particular vapor in question, the adsorbent,
the adsorbent temperature, and the vapor concentration. Removal
of gaseous vapors by physical adsorption is practical for gases
with molecular weight over 45 (31). Each type of activated
carbon has its own adsorbent properties for a given vapor; the
quantity of vapor adsorbed for a particular vapor concentration
in the gas and at a particular temperature is best determined
experimentally. The quantity of vapor adsorbed increases when
the vapor concentration increases and the adsorbent temperature
decreases (29).
(30) Hydrocarbon Pollutant Systems Study, Volume 1. Stationary
Sources, Effects, and Control. Publication No. APTD-1499,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, October 1972. 377 pp.
(31) Chemical Engineers' Handbook, Fifth Edition. J. H. Perry
and C. H. Chilton, eds. McGraw-Hill Book Company, New York,
New York, 1973.
37
-------
After breakthrough has occurred, the adsorbent is regenerated by
heating the solids until the adsorbate has been removed. Low
pressure saturated steam, used as the heat source for activated
carbon, also acts as the carrier gas to remove the vapors
released. Superheated steam at 350°C may be necessary to remove
high boiling compounds and return the carbon to its original con-
dition when high boiling compounds have reduced the carbon capac-
ity to the point where complete regeneration is necessary (29).
Steam requirements for regeneration are a function of external
heat losses and the nature of the organic material. The amount
of steam adsorbed per kilogram of adsorbate, as a function of
elapsed time, passes through a minimum. The carbon should be
regenerated for this length of time to permit the minimum use of
steam (31). After regeneration, the hot, water-saturated carbon
is cooled and dried by blowing organic-free air through the car-
bon bed and evaporating the water. If high temperature steam has
been used, other means of cooling the carbon are required.
Fixed-bed adsorbers arrayed in two or more parallel bed arrange-
ments are used to remove organic vapors from air (see Figure 11).
These are batch-type arrangements, where a bed is used until
breakthrough occurs and is then regenerated. The simplest
adsorber design of this type is a two-bed system where one carbon
bed is being regenerated as the other is adsorbing organic vapors.
In a three-bed arrangement, a greater quantity of material can be
adsorbed per unit of carbon because the effluent passes through
two beds in series while the third bed is being regenerated.
This permits the activated carbon to be used after breakthrough
since the second bed in the series removes organic vapors in the
exit gas from the first bed. When the first bed is saturated, it
is removed from the stream for regeneration; the bed which was
used to remove the final traces of organic vapors form the efflu-
ent then becomes the new first bed; and the bed which has been
regenerated becomes the second new bed (29).
The heat released in the adsorption process causes the tempera-
ture of the adsorbent to increase. If the concentration of
organic vapors is not high, as in the case of room ventilators,
the temperature rise is typically 10°C (29, 32).
The pressure drop through a carbon bed is a function of the gas
velocity, bed depth, and carbon particle size. Activated carbon
manufacturers supply empirical correlations for pressure drop in
terms of these quantities. These correlations usually include
pressure drop resulting from directional change of the gas stream
at inlet and outlet (29).
(32) Air Pollution Engineering Manual, Second Edition. J. A.
Danielson, ed. Publication No. AP-40, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
May 1973. 987 pp.
38
-------
EXHAUST
38 °C
ADSORBER#1
ADSORBER K
"Sv \
PRE-COOLER
-STEAM
38 °C
CONDENSER
COOLING
WATER
CONTAMINATED
STREAM
DECANTER
ORGANIC WASTE
STREAM WATER
Figure 11. Carbon adsorption system (30).
Activated carbon adsorption systems have been reported in the
literature. One system was installed in a latex based operation
for the manufacture of gloves. The gloves were dried in a drying
room to remove traces of solvent and the air from the drying room
was vented into a solvent recovery system operated on 1-hr adsor-
bency cycles. The efficiency of the system was 72% to 73%,
including collection of the vapor-laden air (33).
Absorption
Absorption is the process by which one or more soluble components
are removed from a gas mixture by dissolution in a liquid. The
absorption process may consist of dissolving the component in a
liquid followed by reaction with a reagent, or of solution with-
out reaction (29).
The equipment used for continuous absorption can be a tower
filled with a solid packing material, an enclosure through which
the gas flows and into which the liquid is sprayed, or a tower
which'contains a number of bubble-cap, sieve, or valve-type
(33) Solvent Recovery System Proves a Speedy Payout,
World, 165(5);44, 1972.
Rubber
39
-------
plates. Absorption operations are carried out in a wetted-
wall column (a tubular column in which the gas flows vertically
through the tube and the liquid flows down over the column wall),
a stirred vessel, or other type of equipment (29).
The design of absorbers has been discussed by Treybal (34) and
Perry and Chilton (31). The problems which arise in designing
absorbers can be attributed to variation of solubilities because
of nonisothermal operating conditions, semi-ideal liquid solu-
tions, and the change in the gas and liquid flow rates caused by
transfer of the solute from the gas phase to the liquid phase.
Incineration
Thermal Incineration—
Direct-flame afterburners depend upon flame contact and high
temperatures to burn the combustible material in gaseous emis-
sions to form carbon dioxide and water (35). The combustible
materials may be gases, vapors, or entrained particulate matter
which contributes opacity, odor, irritants, photochemical re-
activity, and toxicity to the emissions. Direct-flame after-
burners consist of a refractory-lined chamber, one or more
burners, temperature indicator-controllers, safety equipment,
and sometimes, heat recovery equipment (35).
The afterburner chamber consists of a mixing section, which
provides contact between the contaminated gases and the burner
flame and a combustion section, which provides high velocity
flow to create turbulence. The combustion section has a reten-
tion time of 0.3 s to 0.5 s for completion of the combustion
process. Afterburner discharge temperatures range from 540°C
to 800°C, depending on the air pollution problem. Higher tem-
peratures result in higher afterburner efficiencies (35).
The gas burners used in afterburners are of the nozzle-mixing,
premixing, multiport, or mixing plate type. Burner placement
varies depending on burner type and on the necessity of provid-
ing intimate contact of the contaminated air with the burner
flames. When all the contaminated air passes through the burner,
maximum afterburner efficiency is obtained (35).
Nozzle-mixing and premixing burners are arranged to fire tan-
gentially into a cylindrical afterburner. Several burners or
nozzles are required to ensure complete flame coverage, and
additional burners or nozzles may be arranged to fire along the
(34) Treybal, R. E. Mass Transfer Operations. McGraw-Hill
Book Company, New York, New York, 1968. 666 pp.
(35) Rolke, R. W., R. D. Hawthorne, C. R. Garbett, E. R. Slater,
and T. T. Phillips. Afterburner Systems Study. EPA-R2-
72-062, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, August 1972. 336 pp.
40
-------
length of the burner. Air for fuel combustion is taken from the
outside air or from the contaminated air stream, which is intro-
duced tangentially or along the major axis of the cylinder (35).
Multiport burners are installed across a section of the after-
burner separate from the main chamber. Although all air for
combustion is taken from the contaminated air stream, multiport
burners are not capable of handling all of the contaminated air
stream. Contaminated air in excess of that used for fuel combus-
tion must be passed around the burner and mixer with the burner
flames in a restricted and baffled area (35).
Mixing plate burners were developed for afterburner applications,
and are placed across the inlet section of the afterburner. The
contaminated air and the burner flames are mixed by profile
plates installed around the burner between the burner and after-
burner walls. The high velocities (1 m/s) provided by the burner
and profile plate design ensure mixing of the burner flames and
the contaminated air not flowing through the burner. The con-
taminated air stream provides air for fuel combustion (35).
The efficiency of an afterburner is a function of retention time,
operating temperatures, flame contact, and gas velocity. No
quantitative mathematical relationship between these variables
exists because the kinetics of the combustion process are com-
plex, and flow inside afterburners is not defined. However, for
good design, the following observations can be made with respect
to afterburner efficiency (35):
• Efficiency increases with increasing afterburner
operating temperature.
• Efficiency decreases if the contaminated gases entering
the afterburner are excessively preheated.
• Efficiency increases with increasing contact between
the contaminated gases and the burner flames.
• Efficiency increases with increasing retention time
for retention times less than one second.
• Efficiency is a function of the afterburner design
and the inlet concentration of organic materials.
• Ninety percent afterburner efficiency is difficult
to reach below a 700°C operating temperature if the
generation of carbon monoxide in the afterburner is
included.
An example of the application of direct-flame incineration to a
plant is reported in the literature (36). A foam products manu-
(36) Sandomirsky, A. G., D. M. Benforado, L. D. Grames, and
C. E. Pauletta. Fume Control in Rubber Processing by
Direct-Flame Incineration. Journal of the Air Pollution
Control Association, 16 (12) :673-676, 1966.
41
-------
manufacturing plant operated a curing oven which exhausted a
stream containing an oil aerosol to the atmosphere. A direct-
flame incinerator with heat recovery equipment was installed.
The incinerator used No. 2 fuel oil as a supplementary fuel. At
a system flow of 14 metric tons/hr and an incineration tempera-
ture of 600°C total hydrocarbons were reduced from 1,305 ppm (by
weight) to 207 ppm, an efficiency of 84%. Allowing for the
contribution of fuel oil, the efficiency becomes 89%. In another
run at a temperature of 640°C, total hydrocarbons were reduced
from 1,055 ppm (by weight), to 89 ppm, for an efficiency of 92%.
Again allowing for the contribution of the fuel oil, the effi-
ciency becomes 97% (36).
Catalytic Incineration—
A catalytic afterburner contains a preheat burner section, a
chamber containing a catalyst, temperature indicators and con-
trollers, safety equipment, and heat recovery equipment. The
catalyst in such an afterburner (shown in Figure 12) promotes
combustion by increasing the rate of the oxidation reactions
without itself appearing to change chemically (29).
PR
BL
FUME STREAM
20 °C TO 200 °C
EHEAT CATALYST
JRNER ELEMENT
_<^--^:^— n n
i — i " 7nn p ~rn c^fin p
^-^-..^reS^r^r JUU L ID 5UU L.
fc*''i
,:&•>;
400 °C TO
600 °C
CLEAN GAS
TO STACK
COMBUSTION/MIXING
CHAMBER
OPTIONAL
HEAT RECOVERY
(REGENERATIVE OR
RECYCLE SYSTEM)
Figure 12. Catalytic afterburner (35).
The contaminated air entering a catalytic afterburner is heated
to the temperature necessary for the catalytic combustion. The
preheat zone temperature, in the range of 340°C to 600°C, varies
with the combustion and type of contaminants. Because of thermal
incineration in the preheat zone, the preheat burner can contrib-
ute to the efficiency of a catalytic afterburner (29).
Catalysts used for catalytic afterburners may be platinum-family
metals supported on metal or matrix elements made of ceramic
honeycombs. Catalyst supports should have high geometric surface
area low pressure drop, structural integrity and durability, and
should permit uniform distribution of the flow of the waste
stream through the catalysts. Catalysts can be poisoned by
phosphorus, bismuth, arsenic, antimony, mercury, lead, zinc, and
tin, which are thought to form alloys with the metal catalyst.
42
-------
Catalysts are deactivated by materials which form coatings on
them, such as particulate material, resins, and the carbon formed
during organic material breakdown. High temperatures will also
deactivate catalysts. Because the combustion reaction is exo-
thermic, the catalyst bed temperature is above the inlet tempera-
ture. The temperature increase depends on the concentration of
organic material burned and the heat of combustion of that mate-
rial. Compensation for decreased catalyst activity can be made
by 1) initial overdesign in specifying the quantity of catalyst
required to attain required performance, 2) increasing preheat
temperature as chemical activity decreases, 3) regenerating the
catalyst, and 4) replacing the catalyst (29).
The quantity of catalyst required for 85% to 95% conversion of
hydrocarbons ranges from 0.5 m3 to 2 m3 of catalyst per 1,000
m3/min of waste stream. Although the catalyst temperature
depends on the hydrocarbon burned and the condition of the cata-
lyst, the operating temperature of catalytic afterburners ranges
from 260°C to 540°C (35).
Vapor Condensation
Organic compounds can be removed from an air stream by condensa-
tion. A vapor will condense at a given temperature when the
partial pressure of the compound is equal to or greater than its
vapor pressure. Similarly, if the temperature of the gaseous
mixture is reduced to the saturation temperature (i.e., the
temperature at which the vapor pressure equals the partial pres-
sure of one of the constituents), the material will condense.
Thus, either increasing the system pressure or lowering the tem-
perature can cause condensation. In most air pollution control
applications, decreased temperature is used to condense organic
materials, since increased pressure is usually impractical (37).
The equilibrium partial pressure limits the control of organic
emissions by condensation. As condensation occurs, the partial
pressure of material remaining in the gas decreases rapidly,
preventing complete condensation. For example, at 0°C and
atmospheric pressure, a gas stream saturated with toluene would
still contain about 8,000 ppm of that gas. Thus, a condenser
must usually be followed by a secondary air pollution control
device such as an afterburner (37).
(37) Control Techniques for Hydrocarbons and Organic Solvent
Emissions from Stationary Sources. Publication No. AP-68,
U.S. Department of Health, Education, and Welfare, Wash-
ington, D.C., March 1970. 113 pp.
43
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PARTICULATE
Wet Scrubbing
Wet scrubbers use a liquid (e.g., water) either to remove parti-
culate matter directly from the gas stream by contact or to
improve collection efficiency by preventing reentrainment. The
mechanisms for particle removal are 1) fine particles are con-
ditioned to increase their effective size, enabling them to be
collected more easily and 2) the collected particles are trapped
in a liquid film and washed away, reducing reentrainment (38).
The effective particle size may be increased in two ways. First,
fine particles can act as condensation nuclei when the vapor
passes through its dew point. Condensation can remove only a
relatively small amount of dust, since the amount of condensa-
tion required to remove high concentrations is usually prohibi-
tive. Second, particles can be trapped on liquid droplets by
impact using inertial forces. The following six mechanisms
bring particulate matter into contact with liquid droplets (38):
Interception occurs when particles are carried by a gas
in streamlines around an obstacle at distances which are
less than the radius of the particles.
Gravitational force causes a particle, as it passes an
obstacle, to fall from the streamline and settle on the
surface of the obstacle.
Impingement occurs when an object placed in the path of
a particle-containing gas stream causes the gas to flow
around it. The larger particles tend to continue in a
straight path because of inertia and may impinge on the
obstacle and be collected.
Diffusion results from molecular collisions and, hence,
plays little part in the separation of particles from
a gas stream.
Electrostatic forces occur when particles and liquid
droplets become electrically charged.
Thermal gradients are important to the removal of matter
from a particle-containing gas stream because particu-
late matter will move from a hot area to a cold area.
This motion is caused by unequal gas molecular collision
energy on the hot and cold surfaces of the particles and
is directly proportional to the temperature gradient.
(38) Control Techniques for Particulate Air Pollutants.
Publication No. AP-51, U.S. Department of Health, Educa-
tion, and Welfare, Washington, D.C., January, 1969. 241 pp.
44
-------
Wet scrubber efficiencies are compared on the bases of contact-
ing power and transfer units. Contacting power is the useful
energy expended in producing contact of the particulate matter
with the scrubbing liquid. The contacting power represents
pressure head loss across the scrubber, head loss of the scrub-
bing liquid, sonic energy, or energy supplied by a mechanical
rotor. The transfer unit (the numerical value of the natural
logarithm of the reciprocal of the fraction of the dust passing
through the scrubber) is a measure of the difficulty of separa-
tion of the particulate matter (38).
Spray Chamber--
The simplest type of wet scrubber is the spray chamber, a round
or rectangular chamber into which water is sprayed either cocur-
rently, countercurrently, or crosscurrently to the gas stream.
Liquid droplets travel in the direction of liquid flow until
inertial forces are overcome by air resistance. Large droplets
settle under the influence of gravity, while smaller droplets
are swept along by the gas stream. These droplets and particu-
late matter may then be separated from the gas stream by gravi-
tational settling, impaction on baffles, filtration through
shallow packed beds, or by cyclonic action (38).
Gravity Spray Tower—
In the gravity spray tower, liquid droplets fall downward through
a countercurrent gas stream containing particulate matter. To
avoid droplet entrainment, the terminal settling velocity of the
droplets is greater than the velocity of the gas stream. Collec-
tion efficiency increases with decreasing droplet size and with
increasing relative velocity between the droplets and air stream.
Since these two conditions are mutually exclusive, there is an
optimum droplet size for maximum efficiency: from 500 ym to
1,000 urn (38).
Centrifugal Spray Scrubbers—
The centrifugal spray scrubber (Figure 13), an improvement on the
gravity spray tower, increases the relative velocity between the
droplets and gas stream by using the centrifugal force of a spin-
ning gas stream. The spinning motion may be imparted by tangen-
tial entry of either the liquid or gas streams or by the use of
fixed vanes and impellers (38).
Impingement Plate Scrubbers--
An impingement plate scrubber (Figure 14) consists of a tower
equipped with one or more impingement stages, mist removal baf-
fles and spray chambers. The impingement stage consists of a
perforated plate that has from 6,500 to 32,000 holes/m2 and a
set of impingement baffles arranged so that a baffle is located
above every hole. The perforated plate has a weir for control
of its liquid level. The liquid flows over the plate and through
a downcomer to a sump or lower stage. The gas enters the lower
sector of the scrubber and passes up through a spray zone created
by a series of low pressure sprays. As the gas passes through
45
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CLEAN GAS
OUT
TOWER NOZZLES,
DIRECTED
CROSS-FLOW
SEPARATOR
IMPINGEMENT
PLATES
RECTANGULAR
INLET
FRESH WATER
SUPPLY
FLUSHING JETS
DIRECTED
DOWNWARD
CLEAN GAS
OUT
WASTE OUT
CYCLONIC SPRAY SCRUBBER.
WATER OUT
MULTI-WASH SCRUBBER.
Figure 13. Centrifugal spray scrubbers (38)
IMPINGEMENT
BAFFLE STAGE
AGGLOMERATING
SLOT STAGE
TARGET
PLATE \
ARRANGEMENT OF "TARGET PLATES'
IN IMPINGEMENT SCRUBBER
WATER DROPLETS ATOMIZED
AT EDGES OF ORIFICES
IMPINGEMENT SCRUBBER
DOWNSPOUT TO
LOWER STAKE
IMPINGEMENT PLATE DETAILS
Figure 14. Impingement plate scrubber (38)
46
-------
the impingement stage, the high gas and particle velocity (2.25
m/s to 3 m/s) atomizes the liquid at the edges of perforations.
The spray droplets, about 10 pm in diameter, increase fine dust
collection (38).
Venturi Scrubbers--
High collection efficiency of fine particles by impingement
requires small obstacle diameter and high relative velocity of
the particle as it impinges on the obstacle. Venturi scrubbers
(Figure 15) accomplish this by introducing the scrubbing liquid
at right angles to a high velocity gas flow in the throat of a
venturi where the velocity of the gas alone causes the disinte-
gration of the liquid. Another factor which affects the effi-
ciency of a venturi scrubber is the conditioning of the particles
by condensation. If the gas in the reduced pressure region in
the throat is saturated or supersaturated, the Joule-Thompson
effect will cause condensation. This helps the particles to
grow, and the wetness of the particle surface helps agglomeration
and separation (38).
Figure 15. Venturi scrubber (38).
Packed Bed Scrubbers—
Packed bed scrubbers (Figure 16) are similar to the packed bed
absorbers discussed previously. The irrigating liquid serves to
wet, dissolve, and/or wash the entrained particulate matter from
the bed. In general, smaller-diameter tower packing gives a
47
-------
GAS OUTLET
LIQUID
DISTRIBUTION UNWETTED
PACKING HEADERS SECTION FOR
SUPPORTMIST ELIMINATION
GRID
ACKING SUPPORT
GRID
CLEAN GAS
OUT
GAS INLET—-
FRONT
CLEANING
SPRAYS
IT
MIST
ELIMINATOR
SECTION
LIQUID
INLET
'V WEIR
DISTRIBUTOR
PACKED
SCRUBBING
SECTION
PACKING
SUPPORT
LIQUID
OUTLET
CROSS-FLOW SCRUBBER COUN TERCURRENT-FLOW SCRUBBER
Figure 16. Packeid scrubbers (38) .
higher particle target efficiency than larger-size packing for a
given gas velocity (38).
Self-Induced Spray Scrubbers--
The Self-induced spray scrubber uses a spray curtain for particle
collection. The spray curtain is induced by gas flow through a
partially submerged orifice or streamlined baffle. Baffles or
swirl chambers are used to minimize mist carryover. The chief
advantage of the self-induced spray scrubber is its ability to
handle high dust concentrations and concentrated slurries (38).
Mechanically Induced Spray Scrubbers--
Mechanically induced spray scrubbers use high velocity sprays
generated at right angles to the direction of gas flow by a par-
tially submerged rotor. Scrubbing is achieved by impaction of
both high radial droplet velocity and vertical gas velocity.
Advantages are the relatively low liquid requirements, small
space requirements, high scrubbing efficiency, and high dust load
capacity. The rotor, however, is susceptible to erosion from
large particles and abrasive dusts (38).
Disintegrator Scrubber--
A disintegrator scrubber consists of a barred rotor with a barred
stator. Water is injected axially through the rotor shaft and is
separated into fine droplets by the high relative velocity of
rotor and stator bars. Advantages of this scrubber are high
efficiency for submicron particles and low space requirements.
The primary disadvantage is its large power requirement (38).
48
-------
Inline Wet Scrubber—
In the axial-fan-powered gas scrubber, a water spray and baffle
screen wet the particles, and centrifugal fan action eliminates
the wetted particles through concentric louvers. Advantages are
low space requirements and low installation costs (38) .
Irrigated Wet Filters—
Irrigated wet filters consist of an upper chamber, containing wet
filters and spray nozzles for cleaning the gas, and a lower
chamber for storing scrubbing liquid. Liquid is recirculated and
sprayed into the surface of the filters on the upstream side of
the bed. Two or more filter stages are used in series (38).
Fabric Filtration
Fabric filters use a filter medium to separate particulate matter
from a gas stream. Two types of fabric filters are in use—high
energy cleaned collectors and low energy cleaned collectors (39).
High Energy Collectors--
High energy collectors use pulse jets to clean the filter medium,
a felt fabric which is kept as clean as possible (39). The pulse
jet is based on the use of an air ejector for dislodging dust
from the bags. The ejector produces a short pulse of compressed
air in the direction opposite to that of the gas being filtered.
The jet must accomplish three things (40):
• Stop the normal filtering flow.
• Transmit a burst of air to the filtration medium, giving
it a vibratory shock.
• Create enough pressure in the bag to ensure a reversal of
flow from the clean side to the dirty side of the bag.
Low Energy Collectors—
Low energy collectors use shaking or reverse air flow methods of
cleaning. The filter base is a woven cloth that acts as a site
on which the true filter medium, or dust cake, can build up (39).
Mist Eliminators
Mists are liquid aerosols (collections of extremely small liquid
particles suspended in an air stream). Incineration, one of
three methods for controlling mists, has already been discussed.
Another technique is scrubbing, but unless high energy scrubbers
are used, extremely fine mist will not be collected. The third
(39) Frey, R. E. Types of Fabric Filter Installations. Journal
of the Air Pollution Control Association, 24(12) :1148-1149 ,
1974.
(40) Bakke, E. Optimizing Filter Parameters. Journal of the Air
Pollution Control Association, 24(12) :1150-1154 , 1974.
49
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method of controlling mists is with mist eliminators, of which
there are four types (41).
Wet Fiber Mist Eliminator--
Wet fiber mist eliminators depend upon two mechanisms, Brownian
diffusion and inertial impaction, to separate mist and dust par-
ticles from air streams. Brownian diffusion dominates when
filter beds have large specific surface areas, gas velocities
range from 1.5 m/min to 9.0 m/min, and the mist consists largely
of submicron-sized particles. A characteristic of such equipment
is that collection efficiency increases with decreasing gas veloc-
ity because of increased filter bed retention time. Brownian
motion is an important factor in particle capture by direct
interception (38).
Inertial impaction dominates in collection of particles above
3 ym in size at gas velocities in excess of 9 m/s in coarse
filter beds. Inertial impaction efficiency increases with
increasing gas velocity (38).
Wetted filters are available in two designs, low velocity (1.5 m/
min to 9 m/min) and high velocity (9 m/min to 27 m/min). The low
velocity design consists of a packed bed of fibers between two
concentric screens as shown in Figure 17. Mist particles collect
on the surface of the fibers, coalesce to form a liquid that wets
the fibers, and are moved horizontally and downward by gravity
and the drag of the gases. The liquid flows down the inner
screen to the bottom of the element to a collection reservoir.
Collection efficiencies are greater than 99% for particles
smaller than- 3 ym in diameter (38).
The high velocity filter consists of a packed fiber bed between
two parallel screens. Liquid flow patterns are similar to those
of the low velocity filter, and removal efficiencies range from
85% to 90% for 1 ym to 3 ym particles (38).
Impingement Baffle Mist Eliminator--
Baffle mist eliminators are used to control large diameter solid
and liquid particles. Mist removal efficiencies of 95% may be
acheived for 40 ym spray droplets up to a maximum gas velocity of
7.6 m/s. Higher gas velocities result in re-entrainment of the
liquid droplets (38).
Vane-Type Mist Eliminators—
Vane-type mist eliminators have an operating range of 3 m/s to
15 m/s with collector efficiences as high as 99% for 11-ym
particles. The principal advantage of the vane-type mist
(41) Farkas, M. D. Mist Abatement from Plastics Processing Oper-
ations. In: Plastics and Ecology - Influence on Pollution,
Flammability, and Safety, Proceedings of the Regional Tech-
nical Conference, The Society of Plastics Engineers, Inc.,
Cherry Hill, New Jersey, October 1970. pp. 9-13.
50
-------
GASKET
SUPPORT PLATE
SCREENS
FIBER PACKING
GAS &MIST
LIQUID DRAINAGE
IIQUIO BACK TO PROCESS
Figure 17. Wet-fiber mist eliminator (41).
eliminator over the baffle type is the wider range of operation
at comparable removal efficiencies (38).
Packed Bed Mist Eliminators--
Packed beds can also be used as mist eliminators. Removal effi-
ciencies range up to 65% at gas velocities of 2 m/s to 3 m/s.
Mist re-entrainment occurs at higher gas velocities (38).
51
-------
SECTION 6
GROWTH AND NATURE OF THE INDUSTRY
For the period 1971 through 1976, plastic resins consumption in
the United States grew at a rate of approximately 8.5% annually,
from 7.91 x 106 metric tons in 1971 to 11.9 x 106 metric tons in
1976. Although consumption in 1976 increased more than 24% over
that of 1975, the apparently vigorous growth by the plastics
industry is lessened by the fact that 1975 sales were the lowest
since 1971. Feedstock shortages, legislative restraints, and the
general slowdown of the American economy during 1975 were the
probable causes of the intervening decline in plastics consump-
tion.
Future growth of the plastics processing industry will be gov-
erned by a complex set of interrelated variables, including, but
not limited to, feedstock availability and cost, future facility
expansion and cost, cost of meeting environmental restrictions,
cost of competitive materials, and the emergence of new marketing
areas. The information presented in this section does not
attempt to account for all of these variables; such as endeavor
is beyond the scope of this document.
Estimated growth patterns for the period 1976 to 1981 were deter-
mined from the literature for all but one plastic type. For
reinforced thermoplastics, 1981 consumption was estimated from
historic growth records.
Table 12 (26, 42-47) shows yearly consumption of 15 plastic
resins for the period 1969 through 1976, average annual growth
(42) The Statistics for 1970. Modern Plastics, 48(l):65-77, 1971,
(43) Materials and Market Statistics for 1971. Modern Plastics,
49(1):41-50, 1972.
(44) Everything's Coming Up Roses, Thorns and All. Modern Plas-
tics, 50(1):52-63, 1973.
(45) Materials and Market Statistics for '73. Modern Plastics,
51(1) :38-47, 1974.
(46) Goodbye, Resin Shortage? Don't You Belivve It! Modern
Plastics, 52(l):44-56, 1975.
(47) The Slow Road Back. Modern Plastics, 53(1):38-51, 1976.
52
-------
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rates for the same period, estimated average growth rates for the
period 1976 through 1981, and estimates of 1981 consumption basecj
on 1976 consumption and projected growth. Figure 18 presents
this information in graphic form.
The following paragraph briefly describes the growth and nature
of those plastics listed in Table 12.
ACRYLIC
The 1976 consumption of acrylics was 2.22 x 105 metric tons,
about 15% higher than in 1975, but still not up to the record
level of 1974. Primary 1976 markets were construction and trans-
portation. An estimated annual growth rate of 6.2% from 1976 to
1981 will yield 3.0 x 105 metric tons of acrylics consumed in
1981 (48).
CELLULOSIC
The 1976 consumption of cellulosics was 7.0 x 104 metric tons,
25% higher than that of 1975, but about 8% lower than that of
1974. The average annual growth rate of cellulosics consumption
from 1971 to 1976 was only 0.6%, and future growth is likely to
be hindered by limited capacity, economics and ecological factors
having recently caused a cutback in chemical-grade cellulosic
production. With an estimated growth rate of 5.9%/yr for 1976
to 1981, cellulosics consumption will reach 9.3 x 10k metric tons
by the end of that period (48).
EPOXY
At 1.00 x 105 metric tons, the 1976 epoxy resins consumption was
30% higher than that of 1975 and 3% higher than that of 1974.
Epoxy resin consumption should reach nearly 1.5 x 105 metric torn
by 1981, assuming an average annual growth rate of 7.9% (48).
Coating (both solvent- and powder-bond), fabricating, and rein-
forced resin applications are expected to be the leading epoxy
markets of the near future.
NYLON
The consumption of nylon resins was 8.8 x 10U metric tons in
1976, up 44% from 1975 and 17% from 1974. Nylon is currently
in ample supply due to improved raw materials availability and
reduced demand for textile fibers and other nylon markets (49).
Future markets in electronics, machinery, and mineral-filled
(48) The Outlook: 1970-1980. Modern Plastics, 47 (1) :97-102,
1970.
(49) Supply Status Report No. 10: Nylons. Modern Plastics,
52(2):52, 1975.
54
-------
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55
-------
materials look promising, and an estimated average growth rate of
8.5%/yr should yield nylon resins consumption of more than
13 x I0k metric tons in 1981 (48).
PHENOLIC
Phenolic consumption in 1976 was 590,000 metric tons, 29% higher
than that of 1975, but only 2% higher than that of 1974. Growth
of phenolics consumption will be limited for several years by
phenol production capacity (50). An average annual growth rate
of 8.9% will lift consumption of phenolic to 900,000 metric tons
in 1981, construction and appliances being the major market areas
(51) .
POLYACETAL
Polyacetal resins showed the greatest percentage change of all 15
plastic types discussed here, increasing from 26,000 metric tons
in 1975 to 39,000 metric tons in 1976. Textile equipment and
other machinery parts are the only growing applications for
polyacetal (46). An optimistic yearly growth rate of 9.9%. yields
1981 consumption of polyacetal resins totalling 63,000 metric
tons (48).
POLYCARBONATE
Polycarbonate consumption was 5.1 x lO4 metric tons in 1976,
approximately 28% higher than that of 1975 and equal to that of
1974. Glazing for housing applications and packaging are the two
most favorable market areas for polycarbonate (47). An estimated
annual growth rate of 10%, considerably less than the 20% experi-
enced from 1971 to 1976, means that 8.2 x I0k metric tons of
polycarbonate resins will be consumed in 1981 (48).
POLYESTER
The 1976 consumption of polyester resins, 6.91 x 105 metric tons,
was 24% higher than that of 1975. Consumption is expected to
grow at an average rate of 9.8% through 1981, faster than the
historical pattern of 1971 to 1976, but slower than might be the
case were it not for anticipated materials shortages (48). The
expected 1981 consumption of polyester resins is 11 x 105 metric
tons.
(50) Supply Status Report No. 6: Phenolics. Modern Plastics,
51(10):64, 1974.
(51) From Now On, Plastics Supply Will Be Just About In Balance
With Demand. Modern Plastics, 52 (10) :40-43, 1975.
56
-------
POLYETHYLENE
The 1976 consumption of high-density and low-density polyethylene
was 3.64 x 106 metric tons, the largest in the plastics industry.
Polyethylene is expected to exhibit a modest growth rate of 7.0%
in the near future, for a 1981 consumption level of 5.1 x 106
metric tons (51). Film and injection-molded products are
expected to continue to lead LDPE consumption, while blow-molded
and injection-molded shapes should maintain a large share of the
HOPE market (52, 53).
POLYPROPYLENE
Polypropylene consumption of 1.008 x 106 metric tons in 1976,
having increased approximately 12% over the 1974 level, showed
the best recovery of all the "volume" resins. This trend is
expected to continue, as the installation of new polymer capacity
should support the estimated average annual growth rate of 15%
(51, 54). Packaging, fibers, and molded appliances are the
products that will lead the way to a 1981 polypropylene consump-
tion of 2.0 x 106 metric tons (54).
POLYSTYRENE AND STYRENE COPOLYMERS
The 1976 consumption of polystyrene and styrene copolymers was
2.112 x 106 metric tons, more than 20% higher than that of 1975,
but still less than the record level of 2.235 x 106 metric tons
in 1973. Growth of styrenic resin consumption should average
5.9% from 1976 to 1981, although benzene availability may be a
limiting factor (51, 55). Packaging, disposable goods, and furn-
iture appear to be the expanding market areas for polystyrene
in the years ahead (48). In 1981, the total consumption of
styrene resins for plastics products should exceed 2.8 x 106
metric tons.
POLYURETHANE FOAM
Polyurethane foam consumption was 738,000 metric tons in 1976, 20%
greater than that of 1975. Both rigid and flexible foams should
continue to grow in usage, especially with the development of new
markets in transportation, furniture, packaging, and construc-
tion (51). The 1981 consumption of polyurethane should be about
(52) Supply Status Report No. 3: HOPE. Modern Plastics,
51(7):52, 1974.
(53) Supply Status Report No. 4: LDPE. Modern Plastics,
51(8):42, 1974.
(54) Supply Status Report No. 5: Polypropylene. Modern Plas-
tics, 51 (9) :78, 1974.
(55) Supply Status Report No. 2: Styrenics. Modern Plastics
51(6):66, 1974.
57
-------
1.2 x 106 metric tons, assuming an average annual growth rate of
9.4% (48).
POLYVINYL CHLORIDE AND COPOLYMERS
Consumption of polyvinyl chloride and copolymers in 1976 was
2.029 x 106 metric tons, an increase of nearly 25% over the level
of 1974. New vinyl chloride monomer (VCM) feedstock and polymer
production facilities should help polyvinyl chloride consumption
to grow at 9.5%/yr, to a 1981 level of 3.2 x 106 metric tons
(51). Pipe and other construction-related areas will probably be
the dominant markets for PVC in the future (51).
REINFORCED THERMOPLASTICS
In 1976, consumption of reinforced thermoplastics was 69,000
metric tons, 25% higher than in 1975 and 11% higher than in 1974.
The most promising application for reinforced thermoplastics is
automobile parts. Extrapolating the 18.1% annual growth rate of
1971 to 1976, consumption of reinforced thermoplastics is esti-
mated to be 160,000 metric tons.
UREA AND MELAMINE
At 439,000 metric tons, 1976 consumption of urea-formaldehyde and
melamine-formaldehyde resins was 22% greater than that of 1975.
Growth in the consumption of amino resins for plywood adhesives
is a good possibility, provided that the slump in the U.S. con-
struction industry comes to an end (48). However, excessive
growth in the construction sector may put undue pressure on
feedstock supplies, forcing some producers of urea and melamine
to other plastics (56). An optimistic average annual growth rate
of 5.4% would yield a 1981 consumption of 570,000 metric tons of
urea and melamine (48).
(56) Supply Status Report No. 7: Urea and Melamine. Modern
Plastics, 51(11) -.59, 1974.
58
-------
REFERENCES
1. Bernhardt, E. C., and J. M. McKelvey. Polymer Processing-
New Engineering Specialty. Modern Plastics, 35 (10) :44-45,
1958.
2. 1972 Census of Manufactures, Volume II-Industry Statistics,
Part 2-SIC Major Groups 27-34. U.S. Department of Commerce,
Washington, D.C., August 1976. pp. 30A-1 through 30A-14.
3. Ott, E. Cellulose and Cellulose Derivatives. John Wiley
and Sons, Inc., New York, New York, 1955. 1601 pp.
4. Travis, G. Cellulosic. Modern Plastics, 50(10A) :34-36,
1973.
5. Terry, H., and S. Nagy. System Analysis of Air Pollutant
Emissions from the Chemical/Plastics Industry. EPA-650/2-
74-106, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, October 1974. 281 pp.
6. Odian, G. Principles of Polymerization. McGraw-Hill Book
Company, New York, New York, 1970. 652 pp.
7. Sherman, S. Epoxy. Modern Plastics, 50(10A):36-40, 1973.
8. Hull, M. E. Phenolic. Modern Plastics, 50(10A):52-56, 1973
9. Martin, R. W. The Chemistry of Phenolic Resins. John Wiley
and Sons, Inc., New York, New York, 1956. 298 pp.
10. Encyclopedia of Polymer Science and Technology, Vol. 12.
John Wiley and Sons, Inc., New York, New York, 1970. p. 32.
11 O'Neill, C. T. Amino. Modern Plastics, 52(10A) : 14-16, 1975,
12. Encyclopedia of Polymer Science and Technology, Vol. 1.
John Wiley and Sons, Inc., New York, New York, 1964.
pp. 482-502.
13. Plastics Sales Data, 1976 vs. 1975: Back Over the
13,000,000-Ton Mark. Modern Plastics, 54(l):49-52, 1977.
14. Encyclopedia of Polymer Science and Technology, Vol. 3.
John Wiley and Sons, Inc., New York, New York, 1967.
pp. 765-830.
59
-------
15. Encyclopedia of Polymer Science and Technology, Vol. 6.
John Wiley and Sons, Inc., New York, New York, 1967.
pp. 466-467.
16. Plastics Engineering Handbook of The Society of the Plastics
Industry, Inc., Third Edition. A. F. Randolph, ed. Rein-
hold Publishing Corporation, New York, New York, 1960.
565 pp.
17. Encyclopedia of Polymer Science and Technology, Vol. 8.
John Wiley and Sons, Inc., New York, New York, 1968. p. 555.
18. Encyclopedia of Polymer Science and Technology, Vol. 6.
John Wiley and Sons, Inc., New York, New York, 1967.
pp. 764-775.
19. Hager, J. E. Polyethylene Film and Sheet. Modern Plastics,
52(10A):138, 1975.
20. Smith, D. E. Casting of PVC Film. Modern Plastics,
52(10A):266, 1975.
21. Gambina, H. J., Jr. Casting of Acrylics. Modern Plastics,
52(10A):263-264, 1975.
22. Encyclopedia of Polymer Science and Technology, Vol. 15.
John Wiley and Sons, Inc., New York, New York, 1971.
pp. 445-479.
23. Encyclopedia of Polymer Science and Technology, Vol. 8.
John Wiley and Sons, Inc., New York, New York, 1968.
pp. 121-148.
24. Muller, G. J. Industrial Laminates. Modern Plastics,
52(10A):153-158, 1975.
25. Encyclopedia of Polymer Science and Technology, Vol. 9.
John Wiley and Sons, Inc., New York, New York, 1968.
pp. 1-157.
26. The World Almanac and Book of Facts 1976. G. E. Delury, ed.
Newspaper Enterprise Association, Inc., New York, New York,
1975. 984 pp.
27. Aerometric and Emissions Reporting System (AEROS), U.S.
Environmental Protection Agency, National Air Data Branch,
Research Triangle Park, North Carolina.
28. Eimutis, E. C., and R. P. Quill. Source Assessment: State-
by-State Listing of Criteria Pollutant Emissions. EPA-
600/2-77-107b, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, July 1977. 138 pp.
60
-------
29. Hughes, T. W., D. A. Horn, C. W. Sandy, and R. W. Serth.
Source Assessment:. Prioritization of Air Pollution from
Industrial Surface Coating Operations. EPA-650/2-75-019-a,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, February 1975. 302 pp.
30. Hydrocarbon Pollutant Systems Study, Volume 1. Stationary
Sources, Effects, and Control. Publication No. APTD-1499,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, October 1972. 377 pp.
31. Chemical Engineers' Handbook, Fifth Edition. J. H. Perry
and C. H. Chilton, eds. McGraw-Hill Book Company, New York,
New York, 1973.
32. Air Pollution Engineering Manual, Second Edition. J. A.
Danielson, ed. Publication No. AP-40, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
May 1973. 987 pp.
33. Solvent Recovery System Proves a Speedy Payout. Rubber
World, 165(5):44, 1972.
34. Treybal, R. E. Mass Transfer Operations. McGraw-Hill Book
Company, New York, New York, 1968. 666 pp.
35. Rolke, R. W., R. D. Hawthorne, C. R. Garbett, E. R. Slater,
and T. T. Phillips. Afterburner Systems Study. EPA-R2-72-
062, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, August 1972. 336 pp.
36. Sandomirsky, A. G., D. M. Benforado, L. D. Grames, and C. E.
Pauletta. Fume Control in Rubber Processing by Direct-Flame
Incineration. Journal of the Air Pollution Control Associa-
tion, 16(12) .-673-676, 1966.
37. Control Techniques for Hydrocarbons and Organic Solvent
Emissions from Stationary Sources. Publication No. AP-68,
U.S. Department of Health, Education, and Welfare, Washing-
ton, D.C., March 1970. 113 pp.
38. Control Techniques for Particulate Air Pollutants. Publica-
tion No. AP-51, U.S. Department of Health, Education, and
Welfare, Washington, D.C., January 1969. 241 pp.
39. Frey, R. E. Types of Fabric Filter Installations. Journal
of the Air Pollution Control Association, 24 (12) : 1148-1149,
1974.
40. Bakke, E. Optimizing Filter Parameters. Journal of the Air
Pollution Control Association, 24 (12) :1150-1154, 1974.
61
-------
41. Farkas, M. D. Mist Abatement from Plastics Processing
Operations. In: Plastics and Ecology - Influence on Pollu-
tion, Flammability, and Safety, Proceedings of the V
Regional Technical Conference, The Society of Plastics
Engineers, Inc., Cherry Hill, New Jersey, October 1970.
pp. 9-13.
42. The Statistics for 1970. Modern Plastics, 48(l):65-77,
1971.
43. Materials and Market Statistics for 1971. Modern Plastics,
49(1):41-50, 1972.
44. Everything's Coming Up Roses, Thorns and All. Modern
Plastics, 50(l):52-63, 1973.
45. Materials and Market Statistics for '73. Modern Plastics,
51(1):38-47, 1974.
46. Goodbye, Resin Shortage? Don't You Believe It! Modern
Plastics, 52(l):44-56, 1975.
47. The Slow Road Back. Modern Plastics, 53(1):38-51, 1976.
48. The Outlook: 1970-1980. Modern Plastics, 47 (1) :97-102,
1970.
49. Supply Status Report No. 10: Nylons. Modern Plastics,
52(2):52, 1975.
50. Supply Status Report No. 6: Phenolics. Modern Plastics,
51(10:64, 1974.
51. From Now On, Plastics Supply Will Be Just About In Balance
With Demand. Modern Plastics, 52(10:40-43, 1975.
52. Supply Status Report No. 3: HOPE. Modern Plastics, 51(7):
52, 1974.
53. Supply Status Report No. 4: LDPE. Modern Plastics, 51(8):
42, 1974.
54. Supply Status Report No. 5: Polypropylene. Modern Plastics,
51(9):78, 1974.
55. Supply Status Report No. 2: Styrenics. Modern Plastics,
51(6):66, 1974.
56. Supply Status Report No. 7: Urea and Melamine. Modern
Plastics, 51(11):59, 1974.
62
-------
57. Turner, D. B. Workbook of Atmospheric Dispersion Estimates.
Public Health Service Publication No. 999-AP-26, U.S. Depart-
ment of Health, Education, and Welfare, Cincinnati, Ohio,
May 1970. 84 pp.
58. Martin, D. O., and J. A. Tikvart. A General Atmospheric
Diffusion Model for Estimating the Effects on Air Quality of
One or More Sources. Presented at the 61st Annual Meeting
of the Air Pollution Control Association, St. Paul, Minne-
sota, June 23-27, 1968. 18 pp.
59. Tadmor, J., and Y. Gur. Analytical Expressions for the
Vertical and Lateral Dispersion Coefficients in Atmospheric
Diffusion. Atmospheric Environment, 3(6):688-689, 1969.
60. Gifford, F. A., Jr. An Outline of Theories of Diffusion in
the Lower Layers of the Atmosphere. In: Meteorology and
Atomic Energy 1968, Chapter 3, D. A. Slade, ed. Publication
No. T1D-24190, U.S. Atomic Energy Commission Technical
Information Center, Oak Ridge, Tennessee, July 1968. p. 113.
61. Code of Federal Regulations, Title 42 - Public Health,
Chapter IV - Environmental Protection Agency, Part 410 -
National Primary and Secondary Ambient Air Quality Standards,
April 28, 1971. 16 pp.
63
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APPENDIX A
CONSUMPTION AND PROCESSING DATA FOR PLASTIC RESINS
TABLE A-l.
1976 CONSUMPTION AND PROCESSING
OF ACRYLIC RESINS (13)
Product type
Cast sheet
Coatings
Molding and extrusion powder
Other
TOTAL
Processing Consumption,
method 103 metric tons
Film and sheet.
Coating.
50% Molding,
50% extrusion.
None .
57
47
63
63
55
222
Percent of
consumption
25.7
21.2
28.4
28.4
24.8
100. I3
Does not equal 100.0% due to erros in rounding.
TABLE A-2.
1976 CONSUMPTION AND PROCESSING
OF CELLULOSIC RESINS (13)
Product type
Automotive
Electrical appliances, radio, TV
Industrial sheeting
Optical goods
Packaging
Personal items
Toys
Tubing
Other
Processing Consumption,
method 103 metric tons
Molding.
Molding.
Film and sheet.
Film and sheet.
Film and sheet.
Molding.
Molding.
Extrusion.
None.
7.0
1.5
8.0
8.0
20.0
16.0
2.5
4.0
3.0
Percent of
consumption
10.0
2.1
11.4
11.4
28.6
22.9
3.6
5.7
4.3
TOTAL
70.0
100.0
64
-------
TABLE A-3. 1976,CONSUMPTION AND PROCESSING OF EPOXY RESINS (13)
Product type
Bonding and adhesives
Flooring , paving , aggregates
Protective coatings :
Appliances finishes
Auto primers
Can and drum coatings
Pipe coatings
Plant maintenance
Other
Reinforced applications :
Electrical laminates
Filament winding
Other
Tooling, casting, molding
Other
TOTAL
Processing
method
Adhesives .
Film and sheet.
Coating .
Coating .
Coating .
Coating .
Coating .
Coating .
Lamination .
Extrusion .
Extrusion .
Molding .
None.
Consumption,
10 3 metric tons
8.0
4.8
3.0
7.0
13.5
2.5
10.5
15.5
7.0
6.5
2.5
7.2
12.0
100.0
Percent of
consumption
8.0
4.8
3.0
7.0
13.5
2.5
10.5
15.5
7.0
6.5
2.5
7.2
12.0
100.0
TABLE A-4. 1976 CONSUMPTION AND PROCESSING OF NYLON RESINS (13)
Product type
Appliances
Consumer products
Electrical/electronics
Filaments and bristle
Film
Machinery parts
Sheet, rod, tube
Transportation
Wire and cable
Other
Processing
method
Molding .
Molding .
Molding .
Extrusion .
Film and sheet.
Molding -
Film and sheet.
Molding.
Extrusion .
None.
Consumption,
10 3 metric tons
5.5
11.0
11.5
8.5
7.0
10.0
5.0
20.0
6.0
3.0
Percent of
consumption
6.3
12.6
13.1
9.7
8.0
11.4
5.7
22.9
6.9
3.4
TOTAL
87.5
100.0
65
-------
TABLE A-5.
1976 CONSUMPTION AND PROCESSING
OF PHENOLIC RESINS (13)
Product type
Processing
method
Consumption,
103 metric tons
Percent of
consumption
Bonding and adhesive resin for:
Coated and bonded abrasives Adhesives.
Fibrous and granulated wood Adhesives.
Friction materials Adhesives.
Foundry and shell moldings Adhesives.
Insulation materials Adhesives.
Laminates:
Building Lamination.
Electrical/electronics Lamination.
Furniture Lamination•
Other Lamination,
Molding compound Molding•
Plywood Adhesives.
Protective coatings Coating.
Other None.
TOTAL
13
32
13
30
96
18
7
12
5
165
132
11
56
590
2.2
5.4
2.2
5.1
16.3
3.1
1.2
2.0
0.8
28.0
22.4
1.9
9.5
100.1°
Does not equal 100.0% due to errors in rounding.
TABLE A-6. 1975 CONSUMPTION AND PROCESSING
OF POLYACETAL RESINS (13)
Product type
Appliances
Consumer products
Electrical/electronics
Machinery parts
Plumbing and hardware
Sheet, rod, tube
Transportation
Other
Processing
method
Molding .
Molding .
Molding .
Molding .
Extrusion .
Film and sheet
Molding •
None .
Consumption ,
10 3 metric tons
3.3
4.3
3.0
10.5
5.7
2.9
7.0
2.3
Percent of
consumption
8.5
11.0
7.7
26.9
14.6
7.4
17.9
5.9
TOTAL
39.0
99.9
Does not equal 100.0% due to errors in rounding.
66
-------
TABLE A-7. 1976 CONSUMPTION AND PROCESSING
OF POLYCARBONATE RESINS (13)
Product type
Appliances
Electrical/electronics
Glazing
Lighting
Signs
Sports and recreation
Transportation
Other
TOTAL
Processing
method
Molding.
Molding.
Molding.
Molding .
Film and sheet.
Molding.
Molding.
None.
Consumption ,
10 3 metric tons
6.9
10.2
15.8
2.0
2.3
2.9
3.9
7.0
51.0
Percent of
consumption
13.5
20.0
31.0
3.9
4.5
5.7
7.6
13.7
99. 9a
Does not equal 100.0% due to errors in rounding.
TABLE A-8.
1976 CONSUMPTION AND PROCESSING
OF POLYESTER RESINS (13)
Product type
Processing
method
Consumption, Percent of
q
103 metric tons consumption
Reinforced products:
Aerospace and aircraft
Appliances
Construction
Consumer products
Corrosion-resistant products
Electrical
Marine
Transportation
Other
Norireinforced products
Surface coatings
TOTAL
Molding.
Molding.
93% Extrusion,
7% film and sheet.
Molding.
Extrusion.
Molding.
Molding.
Molding.
None.
None.
Coating.
9
30
107
35
80
44
150
120
25
86
5
691
1.3
4.3
15.5
5.1
11.6
6.4
21.7
17.4
3.6
12.4
0.7
100.0
67
-------
TABLE A-9.
1976 CONSUMPTION AND PROCESSING OF
HIGH-DENSITY POLYETHYLENE RESINS (13)
Product type
Blow-molded products
Film
Injection-molded products
Pipe, fitting, conduit
Other extruded products
Sheet
Wire and cable
Other
TOTAL
Processing
method
Molding .
Film and sheet.
Molding .
Extrusion .
Extrusion .
Film and sheet.
Extrusion .
None.
Consumption ,
10 metric tons
473
43
291
113
31
25
35
240
1,251
Percent of
consumption
37.8
3.4
23.3
9.0
2.5
2.0
2.8
19.2
100.0
TABLE A-10. 1976
CONSUMPTION
AND PROCESSING
LOW-DENSITY POLYETHYLENE RESINS
OF
(13)
Product type
Blow-molded products
Extrusion coating
Film
Injection-molded products
Pipe and conduit
Other extruded products
Wire and cable
Other
Processing
method
Molding .
Extrusion .
Film and sheet.
Molding.
Extrusion .
Extrusion.
Extrusion.
None .
Consumption ,
10 3 metric tons
23
214
1,472
259
15
24
155
227
Percent of
consumption
1.0
9.0
61.6
10.8
0.6
1.0
6.5
9.5
TOTAL
2,389
100.0
68
-------
TABLE A-ll.
1976 CONSUMPTION AND PROCESSING
OF POLYPROPYLENE RESINS (13)
Product type
Blow-molded products
Extruded products
Fiber and filaments
Film
Injection -molded products
Pipe and conduit
Wire and Cable
Other
TOTAL
Processing Consumption,
method 10 3 metric tons
Molding.
Extrusion .
Extrusion .
Film and sheet.
Molding.
Extrusion .
Extrusd on .
None.
16
36
320
82
425
7
31
91
1,008
Percent of
consumption
1.6
3.6
31.7
8.1
42.2
0.7
3.1
9.0
100.0
TABLE A-12.
1976 CONSUMPTION AND PROCESSING OF POLYSTYRENE
AND STYRENE COPOLYMER RESINS (13)
Product type
Emulsion paint
Extruded products
Foam
Molded products
Textile and paper coating
Other
Processing
method
Coating .
Extrusion .
Foam.
Molding .
Coating.
None .
Consumption ,
10 3 metric tons
9
450
275
977
221
180
Percent of
consumption
0.4
21.3
13.0
46.3
10.5
8.5
TOTAL
2,112
100.0
69
-------
TABLE A-13.
1976 CONSUMPTION AND PROCESSING
OF POLYURETHANE RESINS (13)
Product type
Flexible foam:
Bedding
Furniture
Packaging
Rug underlay
Textile laminates
Transportation
Other
Rigid foam :
Appliances
Building insulation
Furniture
Industrial tanks
Marine flotation
Packaging
Transportation
Other
Thermoplastic polyurethane :
Fabric coating
Film and sheet
Injection-molded products
Laminating adhesives
Leather finishes
Wire coating
Other
Processing
method
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam.
Foam-
Foam.
Coating •
Film and sheet.
Molding .
Adhesives .
Extrusion •
Extrusion .
None.
Consumption,
10 3 metric tons
66
215
10
46
10
195
10
35
75
10
22
6
11
20
7
5.0
1.2
6.3
0.9
0.4
0.8
0.8
Percent of
consumption
8.8
28.5
1.3
6.1
1.3
25.9
1.3
4.6
10.0
1.3
2.9
0.8
1.5
2.7
0.9
0.7
0.2
0.8
0.1
0.1
0.1
0.1
TOTAL
753.4
100.0
70
-------
TABLE A-14. 1976 CONSUMPTION AND PROCESSING OF POLYVINYL
CHLORIDE AND COPOLYMER RESINS (13)
Product type
Apparel:
Baby pants
Footwear
Outerwear
Building and construction:
Extruded foam moldings
Flooring
Lighting
Panels and siding
Pipe and conduit
Pipe fittings
Rainwater system, soffits, fascias
Swimming pool liners
Weatherstripping
Windows, other profiles
Electrical:
Wire and cable
Home furnishings:
Appliances
Furniture
Wall coverings and wood surfacing films
Housewares:
Packaging:
Blow-molded bottles
Closure-liners and gaskets
Coatings
Film
Sheet
Recreation:
Records q
Sporting goods
Toys
Transportation:
Auto mats
Auto tops
Upholstery and seat covers
Miscellaneous:
Agriculture (incl. pipe)
Credit cards
Garden hose
Laminates
Medical tubing
Novelties
Stationery supplies
Tools and hardware
Other
TOTAL
Processing Consumption,
method 10 3 metric tons
Film and sheet.
Film and sheet.
Film and sheet.
Foam.
Film and sheet.
Film and sheet.
Film and sheet.
Extrusion.
Molding.
Film and sheet.
Film and sheet.
Extrusion.
Film and sheet.
Extrusion.
Molding.
Molding.
Coating.
Molding.
Molding-
Molding.
Coating.
Film and sheet.
Film and sheet.
Molding.
Molding.
Molding.
Molding.
Molding-
Molding-
Extrusion.
Film and sheet.
Extrusion.
Lamination.
Extrusion.
Molding-
Molding.
Molding.
None.
9
58
24
21
155
6
42
616
42
14
16
13
21
160
20
95
47
45
36
11
9
80
35
60
24
34
20
14
86
59
7
10
16
19
5
16
6
78
2,029
Percent of
consumption
0.4
2.9
1.2
1.0
7.6
0.3
2.1
30.4
2.1
0.7
0.8
0.6
1.0
7.9
1.0
4.7
2.3
2.2
1.8
0.5
0.4
3.9
1.7
3.0
1.2
1.7
1.0
0.7
4.2
2.9
0.3
0.5
0.8
0.9
0.2
0.8
0.3
3.8
99. 8a
a
Does not equal 100.0% due to errors in rounding.
71
-------
TABLE A-15.
1976 CONSUMPTION AND PROCESSING OF
UREA AND MELAMINE RESINS (13)
Product type
Processing Consumption, Percent of
method 103 metric tons consumption
Bonding and adhesive resins for:
Fibrous and granulated wood
Laminating
Plywood
Molding compounds
Paper treating and coating resins
Protective coatings
Textile treating and coating resins
Other
Adhesives.
Adhesives.
Adhesives.
Molding.
Coating.
Coating.
Coating.
None .
274
14
33
43
24
35
14
2
62.4
3.2
7.5
9.8
5.5
8.0
3.2
0.5
TOTAL
439
100.1
Does not equal 100.0% due to errors in rounding.
72
-------
APPENDIX B
DERIVATION OF SOURCE SEVERITY EQUATIONS3
SUMMARY OF MAXIMUM SEVERITY EQUATIONS
The maximum severity of pollutants may be calculated using the
mass emission rate, Q, the height of the emissions, H, and the
ambient air quality standard, AAQS. The equations summarized in
Table B-l are developed in detail in this appendix.
TABLE B-l. POLLUTANT SEVERITY EQUATIONS
FOR ELEVATED SOURCES
Pollutant
Particulate
SO
X
NO
X
Hydrocarbons
CO
Severity equation
S —
S —
S —
S —
S__
70 Q
H2
50 Q
H2
315 Q
H2.l
162 Q
H2
0.78 Q
H2
DERIVATION OF Y FOR USE WITH U.S. AVERAGE CONDITIONS
max
The most widely accepted formula for predicting downwind ground
level concentrations from a point source is (57)
This Appendix was prepared by T. R. Blackwood and E. C. Eimutis
of Monsanto Research Corporation, Dayton, Ohio.
(57) Turner, D. B. Workbook of Atmospheric Dispersion Estimates
Public Health Service Publication No. 999-AP-26, U.S.
Department of Health, Education, and Welfare, Cincinnati,
Ohio, May 1970. 84 pp.
73
-------
Q
a 'u
y z
exp - T
2 a
y
J
exp
I/ H
2 a
(B-l)
where x - downwind ground level concentration at reference
coordinate x and y with emission height of H, grams
per cubic meter
Q = mass emission rate, grams per .second
a = standard deviation of horizontal dispersion, meters
a = standard deviation of vertical dispersion, meters
Z
u = wind speed, meters per second
y = horizontal distance from centerline of dispersion,
meters
H = height of emission release, meters
x = downwind emission dispersion distance from source of
emission release, meters
u = 3.1416
We assume that Xmax occurs when x is much greater than 0 and when
y equals 0. For a given stability class, standard deviations of
horizontal and vertical dispersion have often been expressed as a
function of downwind distance by power law relationships as
follows (58):
a = axb (B-2)
a = cxd + f (B-3)
^j
Values for a, b, c, d, and f are given in Tables B-2 (59) and B-3
Substituting these general equations into Equation B-l yields
x = ^ exp -[ f 1 (B-4)
acirux + airufx L2 (ex + f) ZJ
Assuming that Xmax occurs when x is less than 100 m or when the
stability class is C, then f equals 0 and Equation B-4 becomes
(58) Martin, D. 0., and J. A. Tikvart. A General Atmospheric
Diffusion Model for Estimating the Effects on Air Quality of
One or More Sources. 61st Annual Meeting of the Air Pollu-
tion Control Association, St. Paul, Minnesota, June 23-27,
1968. 18 pp.
(59) Tadmor, J., and Y. Gur. Analytical Expressions for the Ver-
tical and Lateral Dispersion Coefficients in Atmospheric
Diffusion. Atmospheric Environment, 3(6):688-689, 1969.
74
-------
TABLE B-2.
VALUES OF a FOR THE
COMPUTATION OF a a (59)
Stability class
A
B
C
D
E
F
a
0.3658
0.2751
0.2089
0.1471
0.1046
0.0722
aFor
Equation B-2 :
a = ax
y
where x = downwind distance
b = 0.9031
TABLE B-3.
VALUES OF THE CONSTANTS USED TO
ESTIMATE VERTICAL DISPERSION (57)
Usable range, Stability
m class
>1,000 A
B
C
D
E
F
100 to 1,000 A
B
C
D
E
F
0
0
0
1
6
18
0
0
0
0
0
0
Coefficient
GI
.00024
.055
.113
.26
.73
.05
C2
.0015
.028
.113
.222
.211
.086
2
1
0
0
0
0
1
1
0
0
0
0
di
.094
.098
.911
.516
.305
.18
d2
.941
.149
.911
.725
.678
.74
fl
9.
2.
0.
-13
-34
-48.
f2
9.
3.
0.
-1.
-I.
-0.
6
0
0
6
27
3
0
7
3
35
<100
A
B
C
D
E
F
0.192
0.156
0.116
0.079
0.063
0.053
0.936
0.922
0.905
0.881
0.871
0.814
0
0
0
0
0
0
9For Equation B-3 :
a, =
cxd + f
75
-------
For convenience, let
(B-5)
A)~ri J 1 _ n f\ t-i I
acirux
AR = ir and BR =
so that Equation B-5 reduces to
A -(b+d) / BR\
X = Ax exp
K W2d/
\x /
Taking the first derivative of Equation B-6,
/n -2d\, , ,. -b-d-l) (B-7)
+ exp B x ) (- b - d)x \ v
\ K ' J
and setting this equal to zero (to determine the roots which give
the minimum and maximum conditions of x with respect to x) yields
ARX-b-d-l [eXp(BRx~2d)](- 2 dBRx~2d - b - d) (B-8)
Since we define that x is not equal to 0 or infinity at x > tne
following expression must be equal to 0:
- 2 dB^x~2d - d - b = 0 (B-9)
or
or
9 f\
(b + d)x - - 2 dBD (B-10)
K
2d ~ 2 dBR 2 dH2 dH2 .n ,,.
x = = = (B-ll)
b+d 2 c2(b + d) c2(b + d)
or
X2d = ^ (B-12)
c2(b + d)
Hence
76
-------
x = at x (B-13)
Thus Equations B-2 and B-3 (at f equals 0) become
b
f dH2 1
= a - 2* -
Lc2(d + b)J
//2d
/2d
a - c
z
f d"2 2d - f-^U2 (B-15,
Lc2 (b + d) J \b + d/
The maximum will be determined for U.S. average conditions of
stability. According to Gifford (60), this is when ay equals az.
Since b equals 0.9031, and upon inspection of Table B-2 under
U.S. average conditions, Oy equals az, it can be seen that 0.881
is less than or equal to d, which is less than or equal to 0.905
(Class C stability9) . Thus, it can be assumed that b is nearly
equal to d in Equations B-14 and B-15 or
cr - -2- (B-16)
Z /2
and
- —
c \/2
Under U.S. average conditions, ay equals az and a is approxi-
mately equal to c if b is approximately equal to d and if f
equals 0 (between Classes C and D, but closer to belonging in
Class C) .
Then
a = — (B-18)
Y /2
The values criven in Table B-3 are mean values for stability
class. Class C stability describes these coefficients and
exponents, only within about a factor of two.
(60) Gifford, F. A., Jr. An Outline of Theories of Diffusion in
the Lower Layers of the Atmosphere. In: Meteorology and
Atomic Energy 1968, Chapter 3. Slade, D. A., ed. TID-
24190, U.S. Atomic Energy Commission Technical Information
Center, Oak Ridge, Tennessee, July 1968. p. 113.
77
-------
Substituting for ay from Equation B-18 and for az from Equation
B-16 into Equation B-l and letting y equal 0,
_ 2 Q
"max 2
Xmav = ~ exp|- ^(-^1 I (B-19)
TTUH'
or
2 Q
Y = =—
max TTo
ireuHz
DEVELOPMENT OF SOURCE SEVERITY EQUATIONS
Source severity, S, has been defined as follows:
where x ~ time-averaged maximum ground level concentration
max
F = AAQS
Values of x are found from the following equation:
max
t \°-17
7 = Y - (E-22
xmax xmax \t (
where t is the "instantaneous" (i.e., 3 min) averaging time and
t is the averaging time used for the ambient air quality standard
as shown in Table B-4.
CO Severity
The primary standard for CO is reported for a 1-hr averaging time,
Therefore ,
t - 60 min
t = 3 min
- / 3 \° • x 7
X = (B"23)
^max Amax \60/
2 Q / ^ \0 . 17
(B-24)
2 Q
(2.72) (4.5)H2
78
•(0.6) (B-25)
-------
TABLE B-4. SUMMARY OF NATIONAL AMBIENT AIR QUALITY STANDARDS (61)
Pollutant
Particulate
SO
x
CO
Nitrogen dioxide
Photochemical oxidants
d
Hydrocarbons (nonmethane)
Averaging time,
hr
Annual
(geometric mean)
24b
Annual
(arithmetic mean)
h
3
b
8b
1
Annual
(arithmetic mean)
lb
3
(6 a.m. to 9 a.m.)
Pi imary
standards
75
260
80
365
10,000
40,000
100
160
160
yg/'m3^
(0.03)
24
(0.14)
None .
(9)
(35)
(0.05)
(0.08)
(0.24)
Secondary
standards
(ppm)
60a
150
60
365
260
1,300
40,000
100
160
160
(0.02)
(0.14)
(0.1)
(0.5)
None.
(35)
(0.05)
(0.08)
(0.24)
a 5
The secondary annual standard (60 pg/md) is a guide for assessing implementa-
tion plants to achieve the 24-hr secondary standard.
Not to be exceeded more than once per year.
The secondary annual standard (260 yg/m^ is a guide for assessing implementa-
tion plans to achieve the annual standard.
Recommended guideline for meeting the primary ambient air quality standard
for photochemical oxidants.
X
0.052 Q
max
(0.6!
X
max
H2
3.12 x IP"2 Q
H2
(B-26)
(B-27)
Substituting the primary standard for CO (0.04 g/m3) into the
equation for S then gives
_ Xmax _ 3.12 x 10~2 Q
— —
AAQS 0.04 H2
(B-28)
(61) Code of Federal Regulations, Title 42 - Public Health,
Chapter IV - Environmental Protection Agency, Part 410 -
National Primary and Secondary Ambient Air Quality Standards,
April 28, 1971. 16 pp.
79
-------
or
S = °^§-Q (B-29)
H2
Hydrocarbon Severity
The primary standard for hydrocarbon is reported for a 3-hr
averaging time.
t = 180 min
- / 3 \° • 17
= Xmax (B~30)
= °'5 *max (B
(0.5) (0.052)Q (B-32)
H2
= 0.026 Q
R2
For hydrocarbons, AAQS equals 1.6 x ID"4 g/m3 . Therefore
S = = _ 0.026 Q _ (B_34)
AAQS 1.6 x I0~k H2
or
S = 162'5 Q (B-35)
H2
Particulate Severity
The primary standard for particulate is reported for a 24-hr
averaging time.
3 \° • 1 7
(B~36)
= °-052 Q(0.35) (B-37)
H2
xmax -
For particulates , AAQS equals 2.6 x 10"1* g/m3. Therefore,
80
-------
2.6 x 10-^ H2
(B-39)
S = 2°-Q (B-40)
H2
SO Severity
The primary standard for SOX is reported for a 24-hr averaging
time. Using t equals 1,440 min. and proceeding as before,
For SO , AAQS equals 3.65 x 10"1* g/m3. Therefore,
S = Xmax = 0.0182 Q
AAQS 3.65 x 10-1* H2
or
S = —
H2
N0x Severity
Since NOX has a primary standard with a 1-yr averaging time, the
Xmax correction equation cannot be used. Alternatively, the fol-
lowing equation is used:
- 2.03 Q
= --
exp
z
I/ H
2 a
z
2
(B-44)
A difficulty arises, however, because a distance, x, from emis-
sion point to receptor is included; hence, the following
rationale is used:
Equation B-20 is valid for neutral conditions or when a is
approximately equal to a . This maximum occurs when z
H = /2~a
z
and since, under these conditions,
az = axb
then the distance x where the maximum concentration occurs is
max
81
-------
x = (JL.Y/b
max \/2a /
For Class C conditions, a equals 0.113 and b equals 0.911.
Substituting these values into Equation B-45 yields
(B-45)
x
max \0.16
H
1.098
= 7.5 H1-091
Since
and
a = 0.113 x °'911
z max
u = 4 . 5 m/s
and letting x equal x , Equation B-44 becomes
max
4 Q
max
In Equation B-47, the factor
4 Q
4 Q
Therefore,
As noted above,
x !-911 (7.5 H1-098)1-911
max
0.085 Q
Y = — exp
Amax H2.i
a = 0.113 x°
- 2 a
Substitution for x yields
a = 0.113 (7.5 H1•M °'91
Theref ore,
a = 0.71 H
0.085 Q
=
I/ H \21
- 21077T-HJ J
H
2 . 1
Q(o.371)
(B-46)
(B-47)
(B-48)
(B-49)
(B-50)
(B-51)
(B-52)
(B-53)
(B-54)
82
-------
or
= 3.15 x 10-2 Q
R2>1 (B 55)
Since the N02 standard is 1.0 x 10"^ g/m3, the NO severity
equation is x
S = 3'15 * 10"2 Q (B-56)
1 x 10-1* H2- l
or
S = - (B_57)
H2.1
AFFECTED POPULATION CALCULATION
Another form of the plume dispersion equation is needed to
calculate the affected population since the population is assumed
to be distributed uniformly around the source. If the wind
directions are taken to 16 points and it is assumed that the wind
directions within each sector are distributed randomly over a
period of a month or a season, it can be assumed that the efflu-
ent is uniformly distributed in the horizontal withiri the sector.
The appropriate equation for average concentration, x/ i-n grams
per cubic meter is then (57)
2.03 Q
X = n 11V exp
a ux
z
1
(B-58)
To find the distances at which x/AAQS equals 1.0, roots are
determined for the following equation:
2.03 Q
(AAQS)a ux exp
z
keeping in mind that
I/ H
2 a
2
= 1.0 (B-59)
a = ax + c
where a, b, and c are functions of atmospheric stability and are
assumed to be selected for stability Class C.
Since Equation B-59 is a transcendental equation, the roots are
found by an iterative technique using the computer.
For a specified emission from a typical source, x/&AQS as a func-
tion of distance might look as follows:
83
-------
DISTANCE FROM SOURCE
The affected population is contained in the area
A = IT (X22 - X!2)
(B-60)
If the affected population density is Dp, the total affected
population, P1, is
P1 = DA (persons)
(B-61)
84
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APPENDIX C
INPUT DATA AND OUTPUT FROM AFFECTED POPULATION CALCULATIONS
Populations affected by emissions from 16 representative plastics
processing sources were calculat3d, using the procedure outlined
in Appendix B. Input data and output are shown in Table C-l for
hydrocarbon emissions and particulate emissions from these
plastics plants.
TABLE C-l. AFFECTED POPULATION CALCULATIONS
Hydrocarbon emissions
Plastic type
Acrylic
Cellulosic
Epoxy
Nylon
Phenolic
Polyacetal
Polycarbonate
Polyester
High-density polyethylene
Low-density polyethylene
Po lyp ropy 1 e ne
Polystyrene and styrene copolymers
Polyure thane
Polyvinyl chloride and copolymers
Reinforced thermoplastics
Urea and melamine
Emission
rate.
g/s
3.24
2.68
4.83
2.19
3.12
0.972
3.24
3.07
1.77
2.44
3.38
2.38
22.6
3.98
2.06
3.11
Emission
height.
m
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
Input data
AAQS,
mg/m
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
Wind
Population
Root
speed, density, xlf
m/s
4.5
4.5
.5
.5
.5
.5
.5
.5
.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
persons/km2
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
km
0.022
0.022
0.021
0.023
0.022
0.026
0.022
0.022
0.023
0.022
0.021
0.022
0.018
0.021
0.023
0.022
Root
X2,
km
0.364
0.329
0.451
0.294
0.357
0.186
0.364
0.353
0.262
0.312
0.372
0.308
1.02
0.407
0.285
0.356
Output
Affected
area
km2
0.414
0.338
0.637
0.270
0.398
0.107
0.415
0.391
0.214
0.304
0.434
0.297
3'. 26
0.518
0.253
0.397
Affected
population.
persons
41
34
64
27
40
11
41
39
21
30
43
30
326
52
25
40
(continued)
TABLE C-l (continued)
Plastic type
Acrylic
Cellulosic
Epoxy
Nylon
Phenolic
Polyacetal
Polycarbonate
Polyester
High-density polyethylene
Low-density polyethylene
Polypropylene
Polystyrene and styrene copolymers
Polyurethane
Polyvinyl chloride and copolymers
Reinforced thermoplastics
Urea and melamine
Emission
rate,
g/s
0.498
0.498
0.498
0.498
2.95
0.498
0.498
5.80
0.498
0.498
0.498
0.498
0.498
3.09
0.498
1.28
Emission
height.
m
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.1
Input data
AAQS,
mg/m
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
0.26
Wind
speed
m/s
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
Particulate ends
Population
, density,
persons/km
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
100.
sions
Root
xl ,
km
0.037
0.037
0.037
0.037
0.023
0.037
0.037
0.021
0.1537
0.037
0.037
0.037
0.037
0.023
0.037
0.027
Root
X2,
km
0.086
0.086
0.086
0.086
0.186
0.086
0.086
0.383
0.086
0.086
0.086
0.086
0.086
0.272
0.086
0.164
Output
Affected
area
km2
0.019
0.019
0.019
0.019
0.219
0.019
0.019
0.460
0.019
0.019
0.019
0.019
0.019
0.231
0.019
0.083
Affected
population ,
persons
2
2
2
2
22
2
2
46
2
2
2
2
2
23
2
8
85
-------
APPENDIX D
SAMPLE CALCULATIONS
This section outlines procedures for calculating 1) the source
severity of any of the 16 representative plastics processing
plants and 2) the national and state masses of emissions from
plastics processing.
CALCULATION OF SOURCE SEVERITY
An "overall" emission factor, EF for each plastic type is deter-
mined by summing the products of the fraction, F-j_, of plastic
processed per process operation or handling method and the emis-
sion factor, EFi, for each such operation; i.e.,
EF E 4 (Fi) (EFi) (D-l)
For example, inserting the values from Table 1 and Table 6 for
hydrocarbon emissions from propylene (designated by subscript
..pp..) f
(EP)pp = (0.430)(48 g/kg) + (0.089)(21 g/kg) + (0.481)(20 g/kg) (D-2)
(EF)pp = 32 g/kg (D-3)
The mass emission rate, Q, is calculated by multiplying EF, as
defined in Equation D-l, by the representative production rate
from Section 4, 3,330 metric tons/yr, or 0.106 kg/s.
Therefore,
Q = (0.106 kg/s)(EF, g/kg (D-4)
For the polypropylene example,
(Q)pp = (0.106 kg/s)(32 g/kg) (D-5)
(Q)pp = 3.4 g/s (D-6)
The equation for hydrocarbon severity, derived in Appendix B, is
as follows:
86
-------
s - (B_35)
H2
Substituting the hydrocarbon emission rate calculated above for
polypropylene and the assumed emission height of 6.1 m, the
source severity for hydrocarbons from polypropylene plastics
processing is
c - (162.5) (3.4)
S - (D-7)
PP (6.1)2
Spp - 15 (D-8)
CALCULATION OF NATIONAL AND STATE MASSES OF EMISSIONS
The national masses of emissions from each of 16 different types
of plastics processing, as given in Tables 9 and 10, were calcu-
lated as follows: For each plastic type, the "overall" emission
factor defined by Equation D-l was multiplied by the actual 1976
production of that plastic as listed in Table 1. Therefore, the
total mass of hydrocarbon emissions from polypropylene processing
was (32 g/kg)(1.01 x 106 metric tons) (0.001 kg/g) , or 32,200
metric tons.
The total national masses of criteria pollutant emissions from
plastics processing—4.62 x 105 metric tons of hydrocarbons and
1.57 x 10° metric tons of particulates--were obtained by summing
the total masses of emissions, described above, from each of the
16 different plastic types.
State masses of emissions from plastics processing were calcu-
lated by multiplying the total national mass of a particular
emission by the ratio of the state production to the total U.S.
production. The necessary production data is given in Table 4.
For example, the hydrocarbon emission rate for Ohio is
(4.62 x 105 metric tons/yr) (1.37 x 106 metric tons/yr)/
(1.19 x 105 metric tons/yr), or 5.3 x 106 metric tons/yr.
87
-------
GLOSSARY
acrylic resin: Thermoplastic polymer or copolymer of acrylic
acid, methacrylic acid, esters of these acids, or acrylo-
acrylonitrile.
adhesive: Any substance capable of holding materials together by
surface attachment.
affected population: Number of persons exposed to concentrations
of airborne materials which are present in concentrations
greater than a predetermined hazard factor.
atmospheric stability class: Designation of the degree of turbu-
lent mixing in the atmosphere.
cellulosic plastic: Any of several types of semisynthetic,
thermoplastic polymers based on cellulose.
coating: Thin layer of plastic applied to a base material such
as paper or fabric.
criteria pollutants: Any species for which ambient air quality
standards have been established; these include nonmethane
hydrocarbons, particulates, carbon monoxide, nitrogen
dioxide, and sulfur dioxide.
emission factor: Mass of material emitted to the atmosphere per
unit of product; e.g., grams of hydrocarbons per kilogram
of extruded low-density polyethylene.
epoxy resin: Thermosetting resin produced from epichlorohydrin
and aliphatic or aromatic polyols or from polyolefins and
peracetic acid.
extrusion: Process in which heated or unheated plastic is
forced through a shaping orifice to produce a continuously
formed piece.
film: Continuous sheet having a nominal thickness not greater
than 0.010 in.
foam: Plastic whose density is decreased markedly by the pres-
ence of numerous cavities formed by gaseous displacement.
88
-------
laminate: Composite produce made by bonding together two or
more layers of thermosetting plastic and reinforcing materi-
als such as asbestos, cloth, glass fiber, paper, or wood.
melamine-formaldehyde resin: Thermosetting polymer formed by
the condensation of melamine, an organic compound containing
three amino (-NH2) groups and formaldehyde.
molding, blow: Method of forming hollow objects from plastics
by inflation with compressed gas.
molding, compression: Method of forming solid objects from plas-
tics by placing the material in a confining mold cavity and
applying heat and pressure.
molding, injection: Method of forming solid objects in which
powdered or granular thermoplastics are fused with heat and
pressure and then forced into a cool molding chamber for
solidification.
molding, rotational: Method of forming hollow objects in which
the interior surfaces of a rotating mold are covered with
molten plastics and then chilled to allow product removal.
molding, transfer: Method of forming solid objects from thermo-
setting plastics by forcing the plastic into a heated mold
chamber where curing and solidification occur.
national emission burden: Ratio of the total annual mass of
emissions of a criteria pollutant from a given source type
to the total annual mass of emissions of that pollutant from
all sources nationwide.
nylon: Generic name for a family of thermoplastic polymers
characterized by the presence of amide groups (-CONH).
phenolic resin: One of a number of thermosetting resins synthe-
sized by the condensation of phenols with aldehydes.
polyacetal'resin: Thermoplastic linear polymer formed by
anionic polymerization of formaldehyde.
polycarbonate: Thermoplastic polyester of carbonic acid derived
from bisphenol A and phosgene.
polyester resin: Any of several thermosetting condensation pro-
ducts of dihydroxy alcohols and dicarboxylic acids.
polyethylene, high-density: Thermoplastic polymer of ethylene
with a specific gravity greater than 0.940.
polyethylene, low-density: Thermoplastic polymer of ethylene
with a specific gravity less than 0.940.
89
-------
polypropylene: Crystalline thermoplastic material produced by
catalytic polymerization of propylene.
polystyrene: Synthetic thermoplastic polymer of styrene with a
molecular weight which varies depending upon the degree of
polymerization.
polyurethane: Thermoplastic or thermosetting polymer produced by
the reaction of a polyhydroxy compound and a polyisocyanate.
polyvinyl chloride: Thermoplastic polymer containing the repeat-
ing unit -(H2CCHC1> .
reinforced thermoplastic: Composite material comprising a
thermoplastic resin and glass fibers.
sheet: Individual piece of plastic in which the thickness is
very small relative to length and width.
state emission burden: Ratio of the total annual mass of emis-
sions of a criteria pollutant from a given source type
within a given state to the total annual mass of emissions
of that pollutant from all sources within that state.
thermoplastic: Capable of being repeatedly softened by heating
and hardened by cooling.
thermosetting: Capable of being irreversibly "set" to an infusi-
ble or insoluble state by heating and chemical reaction.
urea-formaldehyde resin: Thermosetting polymer produced by a
two-step catalytic reaction of urea and formaldehyde.
90
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1 TECHNICAL REPORT DATA
(Please read Instructions on. the reverie before completing}
1 REPORT NO,
EPA-600/2-78-004C
7
4. TITLE AND SUBTITLE
SOURCE ASSESSMENT: PLASTICS PROCESSING,
State of the Art
7 AUTHOR(S)
T. W. Hughes, R. F. Boland, and G. M. Rinaldi
g. PERFORMING ORGANIZATION NAME AND ADDRESS
Monsanto Research Corporation
1515 Nicholas Road
Dayton, Ohio 45407
12. SfONSOPINO AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory, Cin., OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45263
15. SUPPLEMENTARY NOTES
IERL-Ci project leader
3. RECIPIENT'S ACCESSION NO.
6 REPORT DATE
March 1978 issuing date
0. PERFORMING ORGANIZATION
8. PERFORMING ORGANIZATION
MRC-DA-705
CODE
REPORT NO
1O. PROGRAM ELEMENT NO.
1AB604
11. C* NTRACT/GRANT NO
68-02-1874
13. TYPE Of REPORT AND PERIOD COVERED
Task Final, 12/74 - 7/77
14. SPONSORING AGFNCY CODE
EPA/600/12
for the report is Ronald J. Turner, 513-684-4481
16. A_BSTRACT
This document reviews the state of the art of air emissions from plants
that manufacture marketable products via plastics processing. The composi-
tion, quantity, rate of emissions, and control technology are described.
The plastics processing industry in the United States produced 1.19 x 107
metric tons of finished goods in 1976 using a variety of types of plastics
which are discussed in the document. To assess the severity of emissions
from this industry, a representative plant was defined for each of the
16 plastic types based on the results of this study. Source severity was
defined as the ratio of the maximum time-averaged ground level concentra-
tion of a pollutant to the primary ambient air quality standard for
criteria pollutants. Hydrocarbon source severities ranged from 4.2 to 98
for polyacetal and polyurethane manufacture, respectively. Source
severities for particulates are also calculated. Plastics processing
contributes 2.8% of the national hydrocarbon emissions and 0.12% of the
national particulate emissions.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Air pollution
Assessments
Plastics processing
18. DISTRIBUTION STATEMENT
Release to the Public
b.lDENTIFIERS/OPEN ENDED TERMS
Air pollution control
Source assessment
Source severity
19 SECURITY CLASS (Thli Report)
Unclassified
30 SECURITY CLASS (Thli pagt>
Unclassified
c. COSATI Field/Group
68A
21 NO. OF PAGES
107
22 PRICE
EPA Form 222O-I 19-13}
91
ft US GOVERNMENT PRINTING OFFICE 1978-2-oO-r
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