United States
Environmental Protection
Agency
Environmental Research
Laboratory
Athens GA 30613
Research and Development
EPA-600/S3-83-064 Nov. 1983
v>ERA Project Summary
Methodology for Estimating
Environmental Loadings from
Manufacture of Synthetic
Organic Chemicals
D.T. O'Leary, K.M. Richter, P.A. Hillis, P.M. Wood, and S.E. Campbell
A methodology was developed for
estimating the multimedia environmen-
tal loadings for a "new" chemical, in
the absence of manufacturing plant
emissions data. This methodology
draws on a multimedia environmental
release data base (ERDB) that contains
information about structurally similar
compounds that undergo similar process
(physical and chemical) unit operations.
The ERDB is integrated with other
pertinent available data on the manu-
facturing process of the new chemical
such as (1) physical and chemical
properties of process feedstock, prod-
ucts, and byproducts; (2) reaction
stoichiometry, thermodynamics, and
reaction kinetics; (3) process flow
diagram and process mass balance; (4)
location and composition of environ-
mental releases and method of disposal;
(5) process environmental control
technology (including performance);
(6) process storage and handling
requirements; and (7) plant equipment
components'(in numbers and classes).
In practice, sufficient direct data are
rarely available for estimating the
environmental loadings of a compound
under review. In every case where data
deficiencies are likely to occur, the
methodology suggests alternative means
for filling the data gaps. The methodol-
ogy integrates all pertinent data to
enable the user to estimate controlled
and uncontrolled loadings under the
classifications of storage and handling,
process, and fugitive emissions. An
example is provided to demonstrate the
applicability of the methodology.
This Project Summary was developed
by EPA's Environmental Research
Laboratory, Athens, GA, to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
The conduct of an exposure assessment
requires reliable environmental release
data, especially for new chemicals. These
chemicals are frequently referred to as
pre-manufacturing notice (PMN) chemi-
cals because of the requirement that an
industry must inform the U.S. Environ-
mental Protection Agency (EPA) of its
plan to manufacture a new compound.
This report presents a methodology
that can be used to determine population
exposure and to identify the most suitable
control options. Determination of the
environmental loadings associated with
the production of a "new" compound is
aided by classifying these loadings as
storage and handling emissions, process
releases, and fugitive emissions
For a precise determination of the
environmental loadings associated with
the production of a "new" compound, it
usually is necessary to conduct a rigorous
field monitoring survey. In the absence of
plant data, which is usually the case for
PMN chemicals, a confident estimate of
plant emissions can be made by integra-
ting data on:
• The manufacturing practices' and
unit processes' multimedia environ-
mental loadings for structurally
similar compounds that undergo
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analogous process (physical and
chemical) unit operations.
• Physical and chemical properties of
process feedstock, products, and
byproducts.
• Reaction stoichiometry, thermo-
dynamics, and reaction kinetics.
• Process flow diagram and process
mass-balance.
• Location and composition of en-
vironmental releases and method of
disposal.
• Process environmental control tech-
nology (including performance).
• Process storage and handling re-
quirements.
• Plant equipment components (in
numbers and classes).
In practice, available direct data on a
compound under review are usually
limited, and the methodology has been
designed with this reality in mind (see
Figure 1). In every case, where data
deficiencies are likely to occur, alternative
means are suggested for filling the data
gaps.
Loading the ERDB
The first step in estimating the environ-
mental release of a "new" chemical is the
loading of the ERDB. This data base
brings together available emissions data
for the 23 major unit processes of the
synthetic organic chemicals manufactur-
ing industry (SOCMI).
The ERDB is organized into 23 categor-
ies that correspond to the 23 major
large-volume SOCMI "unit process"
components that carry out the funda-
mental synthesis reactions, e.g., alkyla-
tion, halogenation, polymerization. Con-
ceptually, the unit process is useful in
that for a given unit process, the physical
or organic chemistry of the compounds
within that unit process tends to be alike
or similar. The significance of the process
waste streams and the industrial impor-
tance of the compounds produced were
also considered in the selection of the
major unit processes.
Environmentally controlled and uncon-
trolled release data are presented for the
three classes (process, storage and
handling, and fugitive) in terms of the
receiving medium (air, land, water).
Process releases are further classified in
terms of the unit operations that occasion
the emissions. For each medium, the data
source is identified along with an
indication of whether quantified or
unquantified data are available.
Reviewing the PMN
The second step of the methodology is
to review the submitted PMN, which is
( Start )
Load the Environmental Release Data Base for1
each one of the 23 process classes. Quantified
data are provided for uncontrolled and con-
trolled releases in terms of:
(i) The major chemicals manufactured
under each process class.
(ii) The location (per unit operation) of
the releases.
(Hi) The receiving medium fair, land, water).
Review the PMN for the following data on the
chemical:
(a) Physical/chemical properties.
(b) Product impurities and chemical
reaction(s) occurring.
(c) Process information (block diagram,
mass balances, location/composition
of environmental releases).
(d) Proposed pollution control equip-
ment/disposal practices.
(e) Production volume.
\
Conduct a Chemistry Review of
"new" related and analogous
chemicals.
Available
Thermodynamics/
Reaction Kinetics
Data
Identify process class to which
"new" chemical manufacturing
process belongs.
Available
Process
Information
Conduct an Engineering
Analysis of production process
of "new" related and analogous
chemicals including materials
balance).
Identify Data Deficiencies
Quantify Process Releases by
medium (air, land, water)
utilizing data provided by:
(i) Chemistry Review
(ii) Engineering Analysis
(Hi) Environmental Release
Data Base
(iv) Engineering judgement
Identify feedstock and product
storage requirements.
Quantify Storage Releases by
medium (air, land, water).
Identify sources of fugitive
emissions
Quantify Fugitive Releases by
medium (air. land, water).
Characterize release data in
terms of reliability.
Identify areas for further
research.
Present data in form required
for in-plant and ex-plant
exposure analysis.
Stop
j
Figure 1. Procedure for the determination of the environmental loading of a "new" chemical.
submitted to EPA by the interested party
at least 90 days before manufacturing of
a new chemical is scheduled. Information
supplied in PMNs varies from only
enough data to fulfill the basic require-
ments of the Toxic Substances Control
Act to data providing a total assessment
of the chemical. The accuracy of estima-
tions using the methodology will depend
on the amount of information supplied.
The single most important piece of data is
the process flow diagram. Engineering
estimates can not be expected to describe
a process as accurately as the flow
diagram. Information is also needed on
the chemical byproducts and methods of
disposal including pollution control
equipment.
Conducting a Chemistry
Review
Available information on the PMN
chemical is reviewed as an aid in
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calculating a materials balance and
resultant emissions. Specific information
is needed on chemical identities and
structures, physical state of components
at ambient conditions, vapor pressures,
solubilities in water, production volume,
and amounts or weights or mole percents
entered or produced to yield production
volume. Also required is information on
chemical reaction(s) involved, side reac-
tion(s), impurities formed, byproducts
formed, percent yield of reaction, physical
state of reaction, catalyst used (if any),
temperature, and pressure.
The physical/chemical properties of
PMN chemicals can be found in the PMN
or the Consumers and Environmental
Exposure Reports (CEER) prepared by the
EPA's Office of Pesticides and Toxic
Substance (OPTS). The physical properties,
environmental fate and pathways, and
health effects of PMN chemicals are
estimated in these reports.
The production volume of the chemical
is given in the PMN. The amounts of
reactants entering can be determined
from a mass balance provided with the
PMN or by looking at the reaction
stoichiometry. Values for the feedstock
impurities, usually by weight percent, can
be obtained from industry-related litera-
ture or from the feedstock producers. As
much impurity information as possible
should be obtained because feedstock
impurities are either released or contri-
bute to side reactions.
OPTS conducts a "chemical review" on
all PMN chemicals, regardless of whether
the reactions are offered in the PMN.
Their results are issued in an Initial
Review Chemistry (IRC) Report. For these
studies, a chemist reviews related and
structurally similar chemicals and their
reactions, side reactions, impurities, and
percent yields.
The reaction kinetics and thermo-
dynamics, as determined by parameters
such as the physical state of the reaction,
its operating conditions, and the catalyst
used, are usually hard to determine, but
indicate the possible emission points and
amounts. Generally, the phase in the
reactor is not readily available information
but sometimes can be deduced by looking
at the physical state of the reactants and
products at ambient conditions and the
process flow diagram.
Conducting an Engineering
Analysis
If a flow diagram is not available, an
engineering analysis can produce a
reasonable description of the process by
reviewing patents of similar chemicals
and using engineering judgement. EPA
produces Engineering Review (ER) Reports
as part of the PMN process. These reports
review the block diagram when it is
provided in the PMN and work out
engineering analyses of possible flow
diagrams when they are not provided
with the PMN. Another flow diagram
source is the construction permits that
companies must submit to their State air
pollution control boards before constructing
or modifying a facility. These permits
contain the proposed process flow
construction or modification and the
estimated resultant air emissions when
in operation. Results using the meth-
odology will not be as accurate without
the actual flow diagram, however.
Determining Process Releases
The methodology addresses two pro-
cedures: (1) how to use the process flow
diagram to identify release points from
unit operations and unit processes, and
(2) how to quantify the process releases
once they have been identified. This
produces a materials balance, an indica-
tion of where emissions might occur, and
a quantification of the large process
emissions. Figure 2 illustrates the
procedures for quantifying process
releases.
Qualitative Analysis of
Releases
The environmental release points are
identified by first looking at the ranking of
releases of the 23 unit processes and
seeing where the PMN chemical manu-
facturing process ranks, based on its type
of unit process. This procedure is then
repeated to identify the unit operations
involved in the PMN process and to judge
how serious their environmental releases
may be. At best, process release ranking
is a screening procedure to quickly
eliminate processes and equipment that
will have small releases. With this
ranking, one knows how severe the
possible air and water releases can be,
based on the 23 unit processes, and also
where efforts should be concentrated in
estimating releases when reviewing the
unit operations.
Because of the wide variation of
behavior within each process class, unit
operations must be analyzed in detail.
The methodology presents tabular data
listing the potential sources of release to
air, water, and land from heating and
cooling steps, reactors, product purifica-
tion and separation unit operations.
Fugitive emissions also occur from all
unit operations as do releases when
equipment is periodically cleaned.
Quantification of Releases
Releases are quantified by obtaining
the material balance from which air
emissions can be estimated for the large
unit processes. All other releases can be
found by analyzing each unit operation
and applying the emission factor ranges
given in the methodology. Data sources
for the mass balance are the PMN and the
ER and IRC reports. A mass balance is
obtained for the reactor and each piece of
separation equipment. Possible emission
points for impurities and byproducts are
also identified.
An inert-carrier gas method is used for
estimating emissions from those unit
processes that release the most air
emissions. Emission projection by the
inert-carrier gas method analyzes the
feed impurities, the excess feed, and the
percent yield of the reaction and multiplies
these by the separation efficiency of the
separation-recovery equipment.
The total gas flow rate and composition
that will be emitted as a result of an inert-
carrier gas process or an air-using
process are estimated. These emissions
are likely to occur from the reactor off-gas
or its absorbers. A large amount of
feedstock purity and separation efficiency
data are required; if these can be provided
then gaseous emissions can be quantified
for this type of process.
In the absence of other methodologies
for estimating emissions, one must use
the ranges of releases to water and land
from unit operations (emission factors)
that the environmental release data base
provides. These ranges are given for the
unit operations for which there were
data. If a unit operation does not have any
release information, then either it is a
small release or it has not been researched.
To quantify emissions by using these
ranges, every piece of information
learned in the qualitative analysis and the
materials balance is used. Where high
and low releases occur and where the
byproducts and their amounts will be
released should be noted. The materials
balance will show the amounts released
and the components of the release. All of
these ranges of releases can then be
added to obtain an overall range of
releases from the PMN process for air,
liquid, and solid releases.
Determining Storage and
Handling Emissions
The synthetic organic chemical manu-
facturing industry has storage and
handling requirements for feedstock,
intermediate and final products, usable
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Nomenclature:
Activity Flow
Information Flow
Qualitative Analysis
of Releases
Quantitative Analysis
of Releases
Classify
Process Flow
Diagram by
Unit Process
Screen Releases by
Unit Process
Air Emissions
Identifies Rank
of Unit Processes <
by ITE Studies
Water Releases
Identifies Rank
of Unit Processes <
by Subcategories
*Low*.
."High
Now Know if Releases From
Process are High or Low
Screen Releases by
Unit Operation
Air Emissions •« — !!_
Water Releases •= cH
Solid Wastes •* ~ Z. _
- High -
~ Low -
- High -
— Low -
- High ~
— Low —
Obtain material balance to identify com-
ponents in releases and realistic amounts.
Quantify by Unit Process
Air Emissions
For processes that can use emission
projections by ITE.
(If not the above mentioned processes
use the unit operations approach).
"^ Use unit operations approach.
Water Releases
,. Ranges of raw waste load re/eases
for each subcategory.
Quantify by Unit Operation
(Using the ERDB)
Air Emissions
Ranges provided for air emissions
No useable data
Water Releases
Ranges provided for water re/eases
No useable data
Solid Wastes
~~ ~ Ranges provided for solid wastes
~~ ~ No useable data
Figure 2. Quantification procedure for process releases.
byproducts, waste tars, residues and
nonusable byproducts.
Storage releases depend on the kind of
storage tank in use, e.g., fixed roof,
floating roof, or pressure tank. The
criteria used for tank selection include
material stability and degrees of safety
and health hazards, but primarily depend
on the vapor pressure of the fluid in
storage. The methodology lists the vapor
pressure ranges that determine the
appropriate tank class plus the use
patterns for storage tanks. Formulae for
calculating the uncontrolled breathing
emissions and working losses for fixed
roof tanks are provided which accountfor
the effects of control technology. Formulae
to calculate standing storage losses and
withdrawal losses from floating roof
tanks are also included.
The report also includes a formula to
calculate loading losses for tank car, tank
truck, and marine vessel loading.
Determining Fugitive
Emissions
Pumps, valves, compressor seals,
flanges, and cooling towers are the major
sources of uncontrolled fugitive releases.
Emissions factors for fugitive sources
have been grouped depending on whether
the process fluid belongs to one of these
categories: vapor service, light-liquid
service, and heavy-liquid service. No data
are available on agitator seals or cooling
tower emission factors.
Once the emission factors for the
uncontrolled and controlled fugitive
emissions for each source are known, it is
necessary to multiply each emission
factor by the number of corresponding
sources to quantify the fugitive releases
per plant. The methodology identifies
data sources useful in determining the
number of fugitive emission sources in a
synthetic organic chemical manufactur-
ing plant.
Establishing Data
Reliability
The data sources used to compile the
ERDB have been classified according to
year of publication, basis used for report-
ing emissions data (plant sampling, ma-
terials balance, estimated data), relation
of emissions factors to plant size, form of
reported emissions, data vintage, and lev-
el of data uncertainty. The four rankings
of data uncertainty are:
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1. Emissions estimated from company
site visits — data of reasonable
accuracy.
2. Emissions estimated from data of
indeterminate accuracy supplied by
a company to state agencies.
3. Emissions estimated from data of
indeterminate accuracy obtained
from other published sources.
4. Emissions of indeterminate accuracy
estimated without supporting data.
Most of the reports have a data
uncertainty level of 3, indicating that
most reports were at best secondary data
sources, i.e., they reported data that were
presented in other cited reports. Also of
note are two additional factors: most of
the report emissions data draw on
estimates rather than observed data, and
most of the reports use data that were
generated more than 5 years ago.
In summary, the ERDB should be used
cautiously in estimating environmental
emissions from "new" synthetic organic
chemicals. Special care should be taken
in using those tables that contain data
from different plants of possibly different
sizes and even from different eras. Since
the chemical industry is dynamic in its
response to new technological and
legislative initiatives, current plant
emission levels are lower than levels
reported a few years ago. Thus, more
reliance may be put on recently completed
studies.
Presenting Data
The format for presenting the data on
environmental releases associated with
the manufacture of a "new" chemical
will be identical to the format used in
presenting the environmental release
data base. Thus, the releases associated
with the functioning of each plant unit
operation are readily accessible and may
be combined with information on the
labor practices associated with the same
unit operations to conduct an in-plant
employee exposure analysis.
The execution of an off-plant analysis of
exposure to plant airborne emissions
would take as its starting point the plant
airborne emissions rate (broken down
into the categories of emission type such
as fugitive, process, and storage residuals)
plus additional information on the
physical and geographical characteristics
of the emissions. These characteristics
include geographic coordinates; source
height (per emission type); and vent
radius, vent gas temperature, ejection
velocity (per emission type).
Additional information on the charac-
teristics of plant emission sources are
discussed in the methodology.
Methodology Limitations
Major limitations of the methodology
and some of the assumptions on which it
was based include:
• Environmental releases are esti-
mated for steady-state, continuous
processes of the synthetic organic
chemical manufacturing industry.
• Releases due to accidents, spills, and
process upsets are not estimated.
• No explicit procedure is provided for
quantifying (unit process) solid
wastes (including spent catalyst
wastes).
• Releases due to the provision of
utilities are not estimated (e.g.,
furnace emissions, boiler blowdown,
etc.)
• In calculating storage, handling, and
fugitive emissions, it is assumed
that the equipment emissions factors
are equivalent to those prevailing in
petroleum refinery operations.
• The methodology tends to group the
environmental releases under broad
classes for air (VOC—volatile organic
carbons) and water (BOD—biological
oxygen demand, COD—chemical
oxygen demand, TOC—total organic
carbon).
• The effects of feedstock variability
on the generation of environmental
residuals are not allowed for explicitly.
Research
Recommendations
The ERDB can be expanded in quality
(by conducting an expanded plant sam-
pling program while simultaneously ob-
serving the kinds and numbers of plant
operators working at each unit operation
throughout the plant) and in breadth (by
measuring the emissions associated with
unit operations which heretofore have not
been extensively observed, e.g., filtration
processes). Particular emphasis should
be put on gathering data on batch
manufacturing processes and on the
amounts of spent catalyst sent for land
disposal.
The methodology could be broadened
to perform sensitivity analysis of the
effects of variations in feedstock quality,
process operating conditions and process
upsets on the process environmental
releases (in quality and quantity); to
generate reliable ranges of solid waste
produced for each unit process; and to
estimate multimedia uncontrolled and
controlled environmental releases on a
compound-by-compound basis.
D. T. O'Leary, K. M. Richter, P. A. Hillis, P. H. Wood, and S. E. Campbell are with
Versar, Inc., Springfield, VA 22151.
K. F. Hedden is the EPA Project Officer (see below).
The complete report, entitled "Methodology for Estimating Environmental
Loadings from Manufacture of Synthetic Organic Chemicals," (Order No. PB
83-241 331; Cost: $41.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protect/on Agency
Athens, GA 30613
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Agency
Center for Environmental Research
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