$EPA
United States Office of Air Quality
Environmental Protection Planning and Standards
Agency Research Triangle Park NC 27711
Air
EPA-450/3-91-012a
JULY 1991
Procedures for DRAFT
Establishing Emissions for
Early Reduction Compliance
Extensions
Volume 1 -- Synthetic Organic
Chemical Manufacturing,
Ethylene Oxide Sterilization, and
Chromium Electroplating
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EPA-450/3-91-012a
This document has not been formally released by EPA and should not now be
construed to represent Agency policy. It is being circulated for comment on its
technical accuracy and policy implications.
Procedures for Establishing
Emissions for Early
Reduction Compliance Extensions
Volume 1 - Synthetic Organic
Chemical Manufacturing,
Ethylene Oxide Sterilization,
and Chromium Electroplating
Emissions Standards Division
. t- - - • - i ! ••" v-7
U S. Environmental "'"
B?»ieux 5, Library ( • »• l '
's'Vl S. Dearborn Str^- - -
Quto«o, IL 60604
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
July 1991
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DISCLAIMER
This report has been reviewed by the Emission Standards Division
of the Office of Air Quality Planning and Standards, EPA, and
approved for publication. Mention of trade names or commercial
products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available
through the Library Services Office (MD-35), U.S. Environmental
Protection Agency, Research Triangle Park NC 27711.
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TABLE OF CONTENTS
Section
INTRODUCTION 1-1
ESTABLISHING HAP EMISSIONS FROM SOCMI SOURCES
2.1 Process Vents 2-3
2.1.1 Acceptable Techniques for
Establishing HAP Emissions
from Process Vents 2-3
2.1.2 Documentation of HAP
Emissions from Process Vents . . . 2-7
2.2 Storage Tanks 2-7
2.2.1 Acceptable Techniques for
Establishing HAP Emissions
from Fixed Roof Storage Tanks . . 2-8
2.2.2 Acceptable Techniques for
Establishing HAP Emissions
from Floating Roof Storage Tanks . 2-12
2.2.3 Documentation of HAP
Emissions from Storage Tanks . . . 2-28
2.3 Equipment Leaks 2-28
2.3.1 Acceptable Techniques for
Establishing HAP Emissions
from Equipment Leaks 2-31
2.3.2 Documentation of HAP
Emissions from Equipment Leaks . . 2-35
2.4 Transfer Operations 2-35
2.4.1 Acceptable Techniques for
Establishing Emissions from
Transfer Operations 2-37
2.4.2 Documentation of HAP
Emissions from Loading Operations. 2-38
2.5 Wastewater Collection and Treatment . . . 2-40
2.5.1 Acceptable Techniques for
Establishing HAP Emissions
from Wastewater Collection and
Treatment 2-42
2.5.2 Documentation of HAP Emissions
from Wastewater Sources 2-46
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TABLE OF CONTENTS (Concluded)
Section Page
3 ESTABLISHING CHROMIUM EMISSIONS FROM CHROMIUM-
ELECTROPLATING OPERATIONS
3.1 Control Techniques/Performance 3-4
3.2 Acceptable Techniques for
Establishing Emissions 3-7
3.2.1 Hard Chromium Plating Operations . 3-8
3.2.2 Decorative Chromium Plating
Operations 3-11
3.2.3 Chromic Acid Anodizing Operations. 3-12
4 ETHYLENE OXIDE STERILIZATION
4.1 Acceptable Techniques for
Establishing HAP Emissions 4-1
4.2 Acceptable Techniques for Establishing
90% HAP Emission Reduction 4-1
APPENDIX A: CALCULATION WORKSHEETS FOR ESTABLISHING
BASE YEAR AND POST-REDUCTION HAP EMISSIONS
FROM SOCMI SOURCES A-l
11
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LIST OF TABLES
Table - page
2-1 Equations for Estimating Fixed-Roof Storage
Tank Emissions 2-9
2-2 Average Storage Temperature (Ts) as a Function
of Tank Paint Color . . . 2-10
2-3 Paint Factors for Fixed Roof Tanks 2-11
2-4 Equations for Estimating Internal Floating Roof
Storage Tank Emissions 2-13
2-5 Equations for Estimating External Floating Roof
Storage Tank Emissions 2-15
2-6 Typical Number of Columns as a Function of Tank
Diameter for Internal Floating Roof Tanks with
Column Supported Fixed Roofs 2-18
2-7 Deck Seam Length Factors (SD) for Typical
Deck Constructions for Internal Floating Roof
Tanks 2-19
2-8 Seal Related Factors for Floating Roof Tanks . . 2-20
2-9 Average Clingage Factors (C) (bbl/1,000 ft2). . . 2-21
2-10 Summary of Internal Floating Deck Fitting
Loss Factors (KF) and Typical Number of
Fittings (NF) 2-22
2-11 External Roof Fitting Loss Factors (Kfa, Kfb)
and Typical Number of Roof Fittings (NF) . . . 2-24
2-12 Typical Number of External Floating Roof Vacuum
Breakers and Drains 2-26
2-13 Typical Number of External Floating Roof Legs. . 2-27
2-14 Leaking and Non-leaking Emission Factors For
Fugitive Emissions (kg/yr/source) 2-33
2-15 Stratified Emission Factors for Equipment
Leaks (kg/yr/source) 2-34
2-16 Saturation (S) Factors for Calculating Organic
Liquid Loading Losses 2-39
111
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LIST OF TABLES (Concluded)
Table Page
2-17 Emission Sources in Wastewater Collection and
Treatment Systems 2-43
IV
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1. INTRODUCTION
On June 13, 1991, EPA proposed "Regulations Governing
Compliance Extensions for Early Reductions of Hazardous Air
Pollutants" (56 FR 27338). The proposed rule implements the
provisions in Section 112 (i) (5) of the Clean Air Act (Act), as
amended in 1990. Those provisions allow an existing source of
hazardous air pollutant emissions to obtain a six-year extension
of compliance with an emission standard promulgated pursuant to
Section 112(d) of the Act, if the source has achieved a reduction
of 90 percent or more of hazardous air pollutants emitted (95
percent or more for particulate pollutants) by certain dates
specified in the Act. If a source is granted a compliance
extension, an alternative emission limitation will be established
by permit to ensure continued achievement of the 90 (95) percent
reduction. The proposed rule establishes requirements and
procedures for source owners and operators to follow in order to
obtain compliance extensions and for reviewing agencies to follow
in evaluating requests for extensions.
One requirement is that requests for a compliance extension
must be submitted to a reviewing agency (EPA or a State agency
with authority to implement this program) and must contain
documentation that the emission reduction has been achieved. To
document the reduction, the owner or operator must provide
emission data for base year (pre-control) and post-control
emissions of hazardous air pollutants emitted by the source. The
proposed rule establishes a presumption that source test results
must be used to satisfactorily document either base year or post-
control emissions. However, the rule also lists circumstances
under which an owner or operator would be allowed to use methods
other than source testing to document emissions for a source (for
example, methods employing engineering calculations, material
balances, or emission factors).
This draft document contains procedures for establishing
emissions for three categories of sources. The three categories
1-1
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covered in this document are synthetic organic chemical
manufacturing, chromium electroplating and chromic acid
anodizing, and ethylene oxide sterilization. Documents covering
additional industries which will be regulated under Section
112(d) of the Act will be issued periodically by EPA.
The intent of this document, and additional documents in
this series, is to provide methods for establishing emissions for
the purposes of the early reduction program, with an emphasis on
methods that can be used when source tests are not required.
Owners or operators may use this document as a guide to preparing
satisfactory emission reduction demonstrations" for compliance
extension requests. However, it is not the intent of this
document to specify the only acceptable methods, other than
source tests, for establishing emissions from a source. EPA
recognizes that, depending on the circumstances, there may be
other ways of satisfactorily showing that hazardous air
pollutants have been controlled sufficiently to qualify for a
compliance extension, and owners or operators are not precluded
from using them. No matter what methods are used, the emissions
established for a source and submitted in a compliance extension
request will undergo review to determine whether they are
adequate for the purposes of the early reduction program.
As a result of comments that may be received relating to the
content of this document, this draft may undergo some revision
before being issued in final form. It is anticipated that a
final version of the document will be available to the public by
September of this year. If a source owner or operator makes a
submittal for the early reduction program based on the
information contained in this draft document and this draft is
revised in a way that invalidates the emission data submitted,
the owner or operator will be given the opportunity to revise the
emission data to conform to the procedures in the final document.
Such revision will be accomplished as part of the review process
for early reduction submittals, as delineated in the proposed
rule.
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2.0 ESTABLISHING HAP EMISSIONS FROM SOCMI SOURCES
Air emission sources in the SOCMI industry can be divided
into five source types. These source types, along with a brief
description, are listed below:
Process Vent Emissions - Emissions from vented process
equipment such as reactors and distillation systems.
Storage Tank Emissions - Emissions from fixed roof and
floating roof storage tanks.
Equipment Leak Emissions - Emissions that occur due to
the escape of process materials through faulty seals in
pumps, valves, compressors, flanges and other
connectors, agitators, sample connections, and open-end
process lines.
Transfer Emissions - Emissions that occur when loading
product into tank trucks, rail cars, and marine
vessels.
Wastewater Collection and Treatment Emissions -
Emissions that result from the volatilization of
organic hazardous air pollutants (HAP) contained in
process wastewater streams.
This section describes the acceptable techniques for
establishing HAP emissions from each of these emission source
types. The basic approaches considered in prescribing acceptable
techniques for each source type included:
(1) Measurement - Calculations based on measured
concentration of the HAP in a waste stream and the flow
rate of the stream.
(2) Established EPA Protocols - Engineering calculation
methods presented in the US EPA publications,
Compilation of Air Pollutant Emission Factors
(EPA-AP-42) and Protocols for Generating Unit-Specific
Emission Estimates for Equipment Leaks of VOC and VHAP
(450/3-88-010). These publications provide engineering
calculation approaches for sources such as storage
tanks, transfer operations, and equipment leaks when
direct measurement is not feasible.
(3) Engineering Calculations - These are calculations based
on physical properties of the HAP, an understanding of
2-1
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the process, and accepted engineering relationships
such as the ideal gas law. The distinction between
this technique and (2) above is that the calculation
procedure has not been previously published as an
accepted EPA procedure for estimating source specific
emissions.
(4) Material Balance - A mass balance around the entire
process or piece of equipment. The amount of chemical
leaving the process equals the amount entering. if
input and product stream values are known and all
losses are to air, then air emissions can be computed
by difference. Any accumulation or depletion of the
HAP by reaction must be accounted for. In general,
material balances produce emission estimates with high
levels of uncertainty. However, in certain situations,
material balances can be used to produce accurate
emission estimates. Material balance can be used, for
example, where the HAP emitted is used as a process
solvent and is not involved in chemical reactions.
(5) Emission Factors - Calculations based on average
measured emissions at numerous facilities in the same
industry. Emission factors can be expressed as a ratio
of emissions to process throughput or an emission rate
independent of throughput. The distinction between
this technique and (2) above is that the factor has not
been previously published as an accepted EPA procedure
for estimating source specific emissions.
The preferred method for determining HAP emissions is
measurement of the emission stream flow and HAP concentration
using published EPA Methods. However, measurement can be
expensive and even impractical in cases where there are large
numbers of individual sources or when the base year conditions no
longer exist at an emission point and cannot be duplicated. When
direct measurement is not feasible, the preferred approach is the
use of established EPA computation methods in AP-42 and Protocols
for Generating Unit-Specific Emission Estimates for Equipment
Leaks of VOC and VHAP (450/3-88-010). In most cases, it should
be feasible to establish HAP emissions data for a source using
only the first two approaches. However, certain situations may
require the use of engineering calculations; and in certain
situations material balances can be used to establish baseline
2-2
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emissions. Specific guidance on the acceptable methodologies for
each source type are provided in the following subsections.
2.1 PROCESS VENTS
Process vents are the vapor exhaust devices on process
equipment in a manufacturing or processing operation. In most
chemical processes, impurities and inerts contained in the raw
materials necessitate the continuous or periodic venting of
noncondensible gases. When released to the atmosphere, volatile
HAPs are carried from the process along with these noncondensible
gases.
Process vents are most commonly associated with reactors and
distillation systems. 'Direct observation of the piping and
instrument diagrams should indicate if process vents exist for a
given unit operation.
2.1.1 Acceptable Techniques for Establishing HAP
Emissions From Process Vents.
The preferred technique for establishing HAP emissions from
process vents is direct measurement. The stream flow should be
determined using EPA Methods 1 through 4; and, when possible, the
HAP concentration should be determined using one of the EPA
Reference methods (prescribed in 40 CFR 60, Appendix A or 40 CFR
61, Appendix A) or an EPA Conditional Method. In many cases, a
validated EPA method will not exist for emissions of the subject
HAP from a specific source type. In such cases, the validation
protocol prescribed in EPA Method 301, Field Validation of
Emission Concentrations From Stationary Sources (450/4-90-015)
should be used to validate the method of choice.1
Establishing HAP emissions for process vents is basically
the same for all process vents, regardless of the unit operation.
The following parameters are required through direct measurement:
Volumetric flow rate of vent gas,
2-3
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Vent gas discharge temperature,
• Concentration of individual or aggregate HAP,
Operating hours per year of unit operation, and
Molecular weight of individual or aggregate HAP.
Emissions of each HAP are calculated as follows:
Eg = 3.94E-08 Q C h MW
T + 460
where,
Eg = uncontrolled HAP emission rate in Mg/yr,
Q = average vent stream flow rate in cubic
feet per minute,
C = HAP concentration in ppm volume,
h = annual hours of operation,
T = vent stream discharge temperature in
degrees fahrenheit,
MW = HAP molecular weight HAP, and
3.94E-08 = conversion factor to yield Mg/yr.
The total HAP emissions are determined by summing the calculated
emissions of each HAP.
In cases where there is a control device present and the
control device was present prior to 1987, the control device
efficiency should be accounted for in determining emissions. The
control device efficiency can be accounted for by: (1) measuring
the stream flow and concentration at the exit of the existing
control device, or (2) using the following expression:
EB = Eg (1 - eff/100)
where,
EB = emissions in Mg/yr,
Eg = uncontrolled emissions in Mg/yr, and
2-4
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eff = measured HAP control efficiency of the
control device.
The latter method actually requires three sets of sampling and
analysis (the individual vent stream, the control device inlet,
and the control device outlet), but may be necessary in ~
situations where the vent stream is combined with other vent
streams prior to control.
In cases where the control efficiency differs for individual
HAPs, it is necessary to perform the above calculations
separately for each HAP and then sum the emissions.
Under certain situations, emissions from process vents can
be established by material balance, in lieu of sampling and
analysis. Material balances can provide accurate determinations
of emissions in cases where the HAP is used as a solvent, there
is no reaction of the HAP, and all losses are to the air or can
be accurately accounted for. In this case, the accuracy of
computed HAP emissions can be as accurate as the determination of
HAP usage. However, material balances are generally inaccurate
in applications outside of the case where the HAP is a process
solvent.
Calculations based on engineering principles are acceptable
only in situations where:
(I) No applicable EPA Reference Method, EPA Conditional
Method, or other source test method exists;
(2) It is not technically or economically feasible to
perform source tests;
(3) It can be demonstrated to the satisfaction of the
reviewing agency that the calculation will provide
emission estimates of accuracy comparable to any
applicable source test method;
(4) The base year conditions no longer exists and cannot be
reproduced and testing under the current conditions and
extrapolating will not produce results more accurate
than an estimate base on engineering principles; or
(5) The emissions from one or a set of emission points in
the source are small compared to total source emissions
2-5
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and errors in estimating emissions from such points
will not have a significant effect on the accuracy of
estimated total emissions from the source.
The significance of an emission point contributes to the
determination of what is technologically or economically feasible
or whether the calculated value is comparable to testing. To
apply the above reasons to a particular source, the owner or
operator and reviewer need to use a common sense approach along
with a knowledge of the emission point to determine if a
calculation procedure is appropriate for establishing emissions.
In general, the owner/operator and reviewer should consider how
much uncertainty in total source emissions would be introduced
through the calculation procedure versus source testing. In some
cases, the reviewer may be able to quantify the relative
uncertainty. In other situations it may only be possible to make
a qualitative judgement on the accuracy. If the uncertainty in
emissions is insignificant when compared to the total emissions
from the facility or when compared to the uncertainty from source
tests, then a calculation procedure is acceptable. For example,
a source has defined three emission points. Total emissions from
two of the three emission points are established by source
testing to be 100 TPY. Emissions from the third emission point
are calculated to be 0.5 TPY using a measured flow along with a
concentration calculated using the ideal gas law and process
conditions prior to discharge. Testing for this emission point
is not necessary. Even if the calculations significantly
underestimated the emissions, the resulting emissions would not
significantly affect the total emissions.
The applicant and the reviewer should not lose site of the
overall goal of the reductions demonstration which is to
determine whether or not the source has made the necessary 90
(95) percent reduction in emissions of HAP. The major emission
points within the source are the critical data points. The most
accurate means of establishing emissions should be used for these
2-6
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emissions. The most accurate means may or may not be testing.
Smaller, insignificant emissions should be established using
reasonable but not necessarily the most accurate procedures. The
applicant is responsible for providing sufficient data to the
reviewer to determine if calculations are acceptable in lieu of
testing.
2.1.2 Documentation of HAP Emissions From Process Vents
In establishing emissions, the following information should
be provided with the computed emission rate:
• Stream identification;
• Vent stream flow rate, method of measurement, and date
of measurement;
• Vent stream discharge temperature;
• Vent stream HAP concentration, method of measurement;
and date of measurement; and
A statement that the measured flow and concentration
are believed to be representative of normal operation.
A form for reporting information used to establish emissions is
provided in Appendix A. In addition, detailed test data and
calibration data collected during sampling and analysis of the
stream should be available upon request.
2.2 STORAGE TANKS
Storage tanks for organic liquids are categorized into five
basic designs: fixed roof, external floating roof, internal
floating roof, variable vapor space, and pressure (high and low).
For the purposes of this document variable vapor space and
pressure tanks are assumed to have insignificant emissions which
may be estimated as zero. Thus variable vapor space and pressure
canks are not discussed any further in this document.
Fixed roof tanks are designed as a cylindrical steel shell
with a permanent roof. The roof may be flat or shaped as a cone
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or dome. Fixed roof tanks have a pressure/vacuum vent which
allows the tanks to operate at a slight internal pressure or
vacuum. However, with significant changes in temperature,
pressure, or liquid level, vapors are released through the vent.
For fixed roof tanks, the vapors emitted are categorized as
breathing losses and working losses. Breathing loss is the
expulsion of vapor from a tank through vapor expansion and
contraction, which results from changes in temperature and
barometric pressure. Breathing loss occurs regardless of the
throughput of the tank. Working loss is due to emptying and
filling of the tank. As the tank empties, air is drawn into the
tank. The outside air becomes saturated with organic vapor and
expands, causing an emptying loss through the relief valve.
Floating roof tanks have a floating deck which rests on the
surface of the organic liquid. The floating deck may also be the
roof of the tank (external floating roof tanks) or the tank may
have a permanent roof with a floating deck inside (internal
floating roof). For internal floating roof tanks, the space
between the floating deck and permanent roof is vented to the
outside to prevent the possibility of explosion. The internal
floating deck either floats directly on the liquid surface or
rests on pontoons several inches above the liquid surface. The
floating deck restricts the evaporation of the organic liquid.
However, evaporation losses may occur between deck fittings,
seams, and the space between the deck and the tank wall.
2.2.1 Acceptable Techniques For Establishing HAP
Emissions From Fixed Roof Storage Tanks
The accepted technique for establishing HAP emissions from
fixed roof storage tanks is the computation technique prescribed
<-\
in AP-42.^ This computation technique, along with methods for
obtaining or estimating the necessary input parameters is
provided in Tables 2-1 through 2-3.
The calculation techniques provided in Tables 2-1 through
2-3 are for pure component materials. In cases where the HAP is
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TABLE 2-1. EQUATIONS FOR ESTIMATING FIXED-ROOF STORAGE TANK
EMISSIONS3
Lrp — LB + L
LB = 1.02 x
P - P
Lw = 1.09 x 10~8 MVPVNKNKC
where,
Lip = total HAP emissions in Mg/yr,
LB = breathing loss emissions in Mg/yr,
Lw = working loss emissions in Mg/yr,
Mv = molecular weight of the HAP,
P = true vapor pressure of the HAP in psia at the
stored material temperature (see Table 2-2) ,
P£ = atmospheric pressure in psia,
D = tank diameter in feet,
H = average vapor space height in feet (use tank
specific values or an assumed value of one-half
the tank height) , . .
T = average diurnal temperature change in °F (20°F can
be used as a typical value) ,
Fp = dimensionless paint factor from Table 2-3,
C = dimensionless tank diameter factor:
C = 1 for diameter >_ 30 feet
C = 0.0771D-0.0013D2-0.1334 for diameter < 30
feet,
Kc = product factor =1.0 for volatile organic HAPs,
V = tank capacity in gallons
N = number of turnovers per year,
KN = dimensionless turnover factor:
KN = 180 + N for turnovers > 36
6N
KN = 1 for turnovers <. 36
aReferences 2 and 3.
2-9
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TABLE 2-2. AVERAGE STORAGE TEMPERATURE (Ts)
AS A FUNCTION OF TANK PAINT COLORa
Average storage temperature,
Tank Color Ts
White TAb + 0
Aluminum TA + 2.5
Gray TA + 3.5
Black TA + 5.0
aReference 2.
"TA is the average annual ambient temperature in degrees
Fahrenheit.
2-10
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TABLE 2-3. PAINT FACTORS FOR FIXED ROOF TANKS3
Tank color
Roof
Shell
Paint factors (Fp;
Paint condition
Good Poor
White
Aluminum (specular)
White
Aluminum (specular)
White
Aluminum (diffuse)
White
Light gray
Medium gray
White 1.00
White 1.04
Aluminum (specular) 1.16
Aluminum (specular 1.20
Aluminum (diffuse) 1.30
Aluminum (diffuse) 1.39
Gray 1.30
Light gray 1.33
Medium gray 1.40
1.15
1.18
1.24
1 .29
1.38
I .46
1.38
1 .44b
1.58b
aReference 3.
bEstimated from the ratios of the seven preceding paint factors
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part of a mixture, the partial pressure of the HAP should be used
in place of the pure component vapor pressure. For mixtures
where the HAP concentration is greater than 1 percent, Raoult's
Law is deemed appropriate for computing the partial pressure.
For mixtures where the HAP concentration is less than 1 percent,
Henry's Law is deemed appropriate for computing the partial
pressure.
2-2.2 Acceptable Techniques For Establishing HAP
Emissions From Floating Roof Storage Tanks
The preferred technique for establishing HAP emissions from
floating roof storage tanks is the computation technique
prescribed in Estimating Air Toxics Emissions From Organic Liquid
Storage Tanks (EPA-450/4-88-004) .2 These equations are provided
in Tables 2-4 and 2-5. The calculation procedures prescribed are
the same as those provided in AP-42, with the addition of fitting
loss calculations for external floating roofs. This additional
component of the external floating roof calculations was obtained
from a study recently completed by the American Petroleum
Institute, Evaporative Loss From External Floating-Roof Tanks
(API Publication 2517) .4
The equations provided in this Section are applicable only
to freely vented internal floating roof tanks and external
floating roof tanks. The equations are not intended to be used
in the following applications: to estimate losses from closed
internal floating roof tanks (tanks vented only through a
pressure-vacuum vent); or to estimate losses from tanks in which
the materials used in the seal system and/or deck construction
are either deteriorated or significantly permeated by the stored
liquid.5
Some notes and guidance for obtaining the less obvious
inputs are provided in the following paragraphs.
Welded roofs. Floating roof tank emissions are the sum of
rim seal, withdrawal, deck fitting, and deck seam losses.
However, it should be noted that external floating roof tanks and
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TABLE 2-4. EQUATIONS FOR ESTIMATING INTERNAL FLOATING ROOF
STORAGE TANK EMISSIONS3
where:
LT = the total loss (Mg/yr)
LW = (0.943) 0 C WL {l + ( ^c£c )]/2205
where D = tank diameter (ft)
Q = product average throughput (bbl/yr)
C = product withdrawal shell clingage factor-
(bbl/10-3 ft2), see Table 2-9
WL = density of the product (Ib/gal)
NQ = number of columns (dimensionless)
Fc = effective column diameter (ft)
LR = the rim seal loss (Mg/yr) = (KRD) P* Mv Kc/2205
LF = the fitting loss (Mg/yr) = (FF) P* Mv Kc/2205
LD = the deck seam loss (Mg/yr) = (FD KD D2) P* Mv Kc/2205
KR = the rim seal loss factor (Ib mole/ft yr) that for an
average fitting seal is as follows:
Seal system description KP (Ib mole/ft vr)
Vapor-mounted primary seal only 6.7
Liquid-mounted primary seal only 3.0
Vapor-mounted primary seal plus
secondary seal • 2.5
Liquid-mounted primary seal plus
secondary seal ]_ _ Q
D = the tank diameter (ft)
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- TABLE 2-4. EQUATIONS FOR ESTIMATING INTERNAL FLOATING ROOF
STORAGE TANK EMISSIONS (CONCLUDED)
P = the vapor pressure function (dimensionless)
P* = 0.068 P/((l + (1 - 0.068 P)0-5)2)
P = true vapor pressure of the HAP stored (psia)
Mv = the average molecular weight of the product vapor
(Ib/lb mole). A typical value for VOL liquids is
80 Ib/lb mole.
Kc = the product factor (dimensionless) =1.0 for VOL
2205 = constant (Ib/Mg)
FF = the total deck fitting loss factor (Ib mole/yr)
n
i=l Fi Fi FI KF!
where:
NF = number of fittings of a particular type
(dimensionless). NF. is determined for the specific
tank or' estimated from Tables 2-6 and 2-10
KFi = deck fitting loss factor for a particular type fitting
(Ib mole yr). KF. is determined for each fitting type
from Table 2-10 r
n = number of different types of fittings (dimensionless)
FD = the deck seam length factor (ft/ft2); see Table 2-7
KD = the deck seam loss factor (Ib mole/ft yr)
= 0 for welded decks
= 0.34 for non-welded roofs
aReferences 2 and 3.
2-14
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TABLE 2-5. EQUATIONS FOR ESTIMATING EXTERNAL FLOATING ROOF
STORAGE TANK EMISSIONS
LT - Lw + LSE + LRF
Lw = 4.28 x 10"4 QCWL/D
LSE = KSVNP*DMVKC/2205
LRF = FFP*MVKC/2205
FF = [ (NF KF ) + (NF KF ) . . . +
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TABLE 2-5. EQUATIONS FOR ESTIMATING EXTERNAL FLOATING ROOF
STORAGE TANK EMISSIONS (CONCLUDED)
Mv = molecular weight of product vapor (Ib/lbmole)
KC = Product factor (dimensionless) = 1.0 for VOL
FF = total roof fitting loss factor, Ib-mol/yr
NF^ = "number of deck fittings of a particular type
(i = 0,1,2,...,nf), dimensionless, see
Table 2-11, 2-12, and 2-13)
KF = roof fitting loss factor for a particular type
fitting (i = 0,1,2,...,nf), Ib-mol/yr, see
Table 2-11
nf = total number of different types of fittings,
dimensionless
2-16
-------
welded internal floating roofs do not have deck seam losses.
There are no procedures in AP-42 for estimating emissions from
external floating roof tank "deck fittings. However, the newly
developed API procedures do include factors for deck fittings.
Number of columns. For a self-supporting fixed roof or
external floating roof, no columns are used. If the number of
columns is not known, Table 2-6 gives a typical number of columns'
based on tank diameter. If the diameter of the columns is
unknown, the following values may be used:
1.1 for 9 inch by 7 inch built-up columns;
0.7 for 8 inch diameter pipe columns; and
1.0 if column construction details are not known.
Deck seam length. For internal floating roof tanks with
bolted decks, the deck seam length factor (SD) may be
approximated if the total length of deck seams is unknown. The
factors are presented in Table 2-7. If no specific information
is available, an SD of 0.20 ft/ft2 can be assumed.
Rim seal losses. For the rim seal loss, the seal factors
and seal related wind speed exponents are listed in Table 2-8.
If no data are available for the type of rim seal, a default of
1.0 may be used.
Clingage factors. For withdrawal loss, the shell clingage
factors are presented in Table 2-9. If no shell condition
information is available, the light rust condition may be
assumed.
Fitting loss factors. Once the number and type of deck
fittings are known for an internal floating roof tank, Table 2-10
is can be used to obtain individual deck fitting loss factors.
For external floating roof tanks, fitting loss factors and the
typical number of roof fittings are provided in Tables 2-11, 2-
12, and 2-13.
Mixtures. In case where the HAP is part of a stored
mixture, the partial pressure of the HAP should be substituted
2-17
-------
TABLE 2-6. TYPICAL NUMBER OF COLUMNS AS A FUNCTION OF TANK
DIAMETER FOR INTERNAL FLOATING ROOF TANKS WITH COLUMN
SUPPORTED FIXED ROOFSa
Tank diameter range Typical number
D (ft) of columns, Nc
0 <
85 <
100 <
120 «
135 «
150 <
170 <
190 <
220 <
235 <
270 <
275 <
290 <
330 <
360 <
C D
C D
c D
C D
C D
c D
C D
C D
C D
C D
C D
: D
C D
: D
: D
< 85
< 100
< 120
< 135
< 150
< 170
< 190
< 220
< 235
< 270
< 275
< 290
< 330
< 360
< 400
1
6
7
8
9
16
19
22
31
37
43
49
61
71
81
This table was derived from a survey of users and
manufacturers. The actual number of columns in a particular tank
may vary greatly with age, fixed roof style, loading
specifications, and manufacturing perogatives. Data in this
table should not supersede information on actual tanks.
2-18
-------
TABLE 2-7. DECK SEAM LENGTH FACTORS (SD) FOR TYPICAL
DECK CONSTRUCTIONS FOR INTERNAL FLOATING ROOF TANKS3
Typical deck seam
length factor,
Deck Construction SD (ft/ft^)
Continuous sheet construction13 0.20°
5 ft wide 0.17
6 ft wide 0.14
7 ft wide
Panel construction01
5 x 7.5 ft rectangular 0.33
5 x 12 ft rectangular 0.28
aReference 2. Deck seam loss applies to bolted decks only.
bSD = I , where W = sheet width (ft)
w
clf no specific information is available, these factors can be
assumed to represent the most common bolted decks currently in
use.
2-19
-------
TABLE 2-8. SEAL RELATED FACTORS FOR FLOATING ROOF TANKSa
Welded Tank Reveted Tank
Tank and seal type KS N Ks N
External floating roof tanks13
Metallic shoe seal 1.2 1.5 1.3 1.5
Primary seal only 0.8 1.2 1.4 1^2
With shoe mounted secondary seal 0.2 1.0 0.2 1.6
With rim mounted secondary seal
Liquid mounted resilient seal 1.1 l.Q NAC NA
Primary seal only 0.8 0.9 NA NA
With weather shield 0.7 0.4 NA NA
With rim mounted secondary seal
Vapor mounted resilient seal 1.2 2.3 NA NA
Primary seal only 0.9 2.2 NA NA
With weather shield 0.2 2.6 NA NA
With rim mounted secondary seal
Internal floating roof tanks01
Liquid mounted resilient seal 3.0 0 NA NA
Primary seal only 1.6 0 -NA NA
With rim mounted secondary seal6
Vapor mounted resilient seal 6.7 0 NA NA
Primary seal only 2.5 0 NA NA
With rim mounted secondary seal6
aBased on emissions from tank seal systems in reasonably good
working condition, no visible holes, tears, or unusually large gaps
between the seals and the tank wall. The applicability of Ks
decreases in cases where the actual gaps exceed the gaps assumed
during development of the correlation.
DReference 3.
CNA = Not Applicable.
dReference 2.
elf tank specific information is not available about the secondary
seal on an internal floating roof tank, then assume only a primary
seal is present.
2-20
-------
TABLE 2-9. AVERAGE CLINGAGE FACTORS (C) (bbl/1,000 ft2)a
Liquid
Gasoline
Single component
Light rust0
0.0015
0.0015
Shell condition
Dense rust Gunite
0.0075 0.
0.0075 0.
lined
15
15
stocks
Crude oil 0.0060 0.030 0.60
aReference 2.
blf no specific information is available, these values can be
assumed to represent the most common condition of tanks currently
in use.
2-21
-------
TABLE 2-10. SUMMARY OF INTERNAL FLOATING DECK FITTING LOSS
FACTORS (KF) AND TYPICAL NUMBER OF FITTINGS (Nj
Deck fitting type
Deck fitting
loss factor, KF
(Ib-mole/yr)
Typical number
of fittings
(see Table 2-5)
Access hatch
Bolted cover, gasketed 1.6
Unbolted cover, gasketed 11
Unbolted cover, ungasketed 25b
Automatic gauge float well
Bolted cover, gasketed 5.1
Unbolted cover, gasketed 15
Unbolted cover, ungasketed 28b
Column well
Builtup column-sliding cover, gasketed 33
Builtup column-sliding cover, 47b
ungasketed .
Pipe column-flexible fabric sleeve seal 10
Pipe column-sliding cover, gasketed 19
Pipe column-sliding cover, ungasketed 32
Ladder well
Sliding cover, gasketed 56
Sliding cover, ungasketed 76b
Roof leg or hanger well
Adjustable
Fixed 7 _gb
0
Sample pipe or well
Slotted pipe-sliding cover, gasketed 44
Slotted pipe-sliding cover, ungasketed 57
Sample well-slit fabric seal, I2b
10 percent open area
Stub drain, 1 inch diameterd 1.2
(5 + _D
10
600
-a2,0
125
1
Vacuum breaker
Weighted mechanical actuation, 0.7b
gasketed
Weighted mechanical actuation, 0.9
ungasketed
aReference 2.
blf no specific information is available, this value can be assumed
to represent the most common/typical deck fittings currently used.
2-22
-------
TABLE 2-10. SUMMARY OF INTERNAL FLOATING DECK FITTING LOSS
FACTORS (KF) AND TYPICAL NUMBER OF FITTINGS (NF)a (CONCLUDED)
CD = tank diameter (ft).
used on welded contact internal floating decks.
2-23
-------
TABLE 2-11.
EXTERNAL ROOF FITTING LOSS FACTORS (Kfa/ Kfb) AND
TYPICAL NUMBER OF ROOF FITTINGS (NF)a
Roof fitting loss factors
Roof fitting type and construction details
1.
2.
3.
4.
5.
6.
7.
Access hatch (24-inch diameter well)
a. Bolted cover, gasketed
b. Unbolted cover, ungasketed
c. Unbolted cover, gasketed
Guide pole well (8-inch diameter unslotted pole,
21-Inch diameter well)
a. Ungasketed sliding cover, without float
b. Gasketed sliding cover
Guide pole/sample well {8-inch diameter slotted pole,
21-inch diameter well)
a. Ungasketed sliding cover, without float
b. Ungasketed sliding cover, with float
c. Gasketed sliding cover, without float
d. Gasketed sliding cover, with float
Gauge float well (20-inch diameter well)
a. Unbolted cover, ungasketed
b. Unbolted cover, gasketed
c. Bolted cover, gasketed
Gauye hatch/sample well (8-lnch diameter well)
a. Weighted mechanical actuation, gasketed
b. Weighted mechanical actuation, ungasketed
Vacuum breaker (10-inch diameter well)
a. Weighted mechanical actuation, gasketed
b. Weighted mechanical actuation, ungasketed
Root drain (3-inch diameter)
a . Open •
b. Closed, 90 percent
Ib-lfSle
/ I
yr
0
2.7
2.9
0
0
0 '
0
0
0
2.3
2.4
0
0.95
0.91
1.2
1.1
0
0.51
K,K
Ib-m8le
/ I
[ml/h)n yr
0
7.1
0.41
67
3.0
310
29
260
8.5
5.9
0.34
0
0.14
2.4
0.17
3.0
7.0
0.81
m Typics 1 No . ,
(dimenslonless) of fittings, NF
b 1
• o°
1.0
1.0
1
U
0.98D
1.4
c
1.2
2.0
1.2
2.4
b 1
1.0b
1.0
0
b 1
1.0b
1.0
. See Table 2-12
1.0°
1.0
See Table 2-12
1.4*
1.0e
(continued)
-------
TABLE 2-11. EXTERNAL ROOF FITTING LOSS FACTORS (Kfa, Kfb) AND
TYPICAL NUMBER OF ROOF FITTINGS (NF)a (CONCLUDED)
Rnr,f f Iff Ing loss factors
Ib-m8le
Roof fitting type and construction details
8. Roof
a .
b.
c .
D.
Roof
e .
f .
9-
h.
9. Rim
a.
b.
leg (3-inch diameter leg)
Adjustable, pontoon area
Adjustable, center area
Adjustable, double-deck roofs
Fixed
leg (2 1/2 inch diameter leg)
Adjustable, pontoon area
Adjustable, center area
Adjustable, double-deck roofs
Fixed
vent (6-lnch diameter)
Weighted mechanical actuation, gasketed
Weighted mechanical actuation, ungasketed
1
0
0
1
0
0
0
0
.5
.25
.25
0
.7
.41
.41
0
.71
.68
Ib-^She
( '1
(ml/h]n yr
0.20
0.067
0.067
0
0.10
1.8
m Typical No. b
(dimensionless) of fittings, NF
See Table 2-13
1 Ob
l:0b
1.0
0
Q
o
o
! i.od
1 Ob
1.0
1 aThe roof fitting loss factors (K£a> Kfb/ m) may be used only for wind speeds from 2 to 15 ml/h.
01 blf no specific information is available, this value can be assumed to represent the most common or typical roof fittings currently in use.
GGuide poie/sample well is an optional fitting not typically used.
Rim vents are used only with mechanicai shoe primary seals.
eRoof drains that drain excess rainwater into the product are not used on pontoon floating roofs. They are, however, used on double-deck floating roofs
and are typically left "open."
-------
TANK 2-12. TYPICAL NUMBER OF VACUUM BREAKERS AND
ROOF DRAINS, NF
Tank
Diameter,
D(feet) a
50
100
150
200
250
300
350
400
Number of
Vacuum Breakers
, NT7
Pontoon Double-deck
Roof Roof
1
1
2
3
4
5
6
7
1
1
2
2
3
3
4
4
Number of
Roof Drains, NF
(Double-deck
Roof)b
1
1
2
3
5
7
-
-
alf the actual diameter is between the diameters listed, the closet
diameter listed should be used. If the actual diameter is midway
between the diameters listed, the next larger diameter should be
used.
bRoof drains that drain excess rainwater into the product are not
used on pontoon floating roofs. They are, however, used on
double-deck floating roofs and are typically left -open.
2-26
-------
TANK 2-13. TYPICAL NUMBER OF EXTERNAL FLOATING ROOF LEGSa
Tank Pontoon Roof Double-deck
diameter, d(ft)b Pontoon legs Center legs roof legs
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
4
4
6
9
13
15-
16
17
18
19
20
21
23
26
27
28
29
30
31
32
33
34
35
36
36
37
38
38
39
39
40
41
42
44
45
46
47
48
2
4
6
7
9
10
12
16
20
24
28
33
38
42
49
56
62
69
77
83
92
101
109
118
128
138
148
156
168
179
190
202
213
226
238
252
266
281
6
7
8
10
13
16
20
25
29
34
40
46
52
58
66
74
82
90
98
107
115
127
138
149
162
173
186
200
213
226
240
255
270
285
300
315
330
345
aThis table was derived from a survey of users and manufacturers.
The actual number of roof legs may vary greatly depending on age,
floating roof style, loading specifications, and manufacturing
prerogatives. This table should not supersede information based
on actual tank data.
blf the actual diameter is between the diameters listed, the
closest diameter listed should be used. If the diameter is midway
between the diameters listed, the next larger diameter should be
used.
2-27
-------
for the pure component vapor pressure as described above for
fixed roof tanks.
2.2.3 Documentation of HAP Emissions From Storage Tanks
All storage tank characteristics, tank throughput data, and
HAP physical"property data used to perform storage tank emission
calculations should be provided for each tank. A set of forms
listing the required computation inputs is provided in
Appendix A. The appropriate form in Appendix A should be
completed and submitted for each storage tank.
2.3 EQUIPMENT LEAKS
Leaks occur from plant equipment that have a point of
interface of the process fluid with the atmosphere. These points
of interface such as seals, packings, and gaskets have a tendency
to fail mechanically and thereby leak process fluid. The major
sources of equipment leaks include pumps, valves, flanges and
other connectors, compressors, sampling connection systems, open-
ended lines, agitators, and pressure relief valves. Detailed
discussions of these emission sources are presented in two EPA
reports.6'7 A brief discussion of these sources is presented
below.
Pumps. Pumps are used extensively in process units for the
movement of organic liquids. The centrifugal pump is the most
widely used pump. However, other types, such as the positive-
displacement, reciprocating and rotary action, and special canned
and diaphragm pumps, are also used. Chemicals transferred by
pumps can leak at the point of contact between the moving shaft
and stationary casing. Consequently, all pumps except the
shaftless type (canned-motor and diaphragm) require a seal at the
point where the shaft penetrates the housing in order to isolate
the pump's interior from the atmosphere.
Two generic types of seals, packed and mechanical, are
currently in use. Packed seals can be used on both reciprocating
2-28
-------
and rotary action types of pumps. A packed seal consists of a
cavity ("stuffing box") in the pump casing filled with special
packing material that is compressed with a packing gland to form
a seal around the shaft, Deterioration of the packing results in
process liquid leaks.
Mechanical seals are limited in application to pumps with
rotating shafts and can be further categorized as single and
double mechanical seals. Depending on the condition and flatness
of the seal faces, the leakage rate from a mechanical seal can be
quite low (as small as a drop per minute) and the flow is often
not visually detectable. In order to minimize emissions due to
seal leakage, an auxiliary sealing device such as packing can be
employed.
Valves. The types of valves commonly used in organic
chemical plants are globe, gate, plug, ball, relief, and check
valves. All except the relief valve (to be discussed further
below) and check valve are activated by a valve stem, which may
have either a rotational or linear motion, depending on the
specific design. This stem requires a seal to isolate the
process fluid inside the valve from the atmosphere. The
possibility of a leak through this seal makes it a potential
source of emissions. Since a check valve has no stem or
subsequent packing gland, it is not considered to be a potential
source of emissions.
Compressors. Gas compressors used in process units are
similar to pumps in that they can be driven by rotary or
reciprocating shafts. They are also similar to pumps in their
need for shaft seals to isolate the process gas from the
atmosphere. As with pumps, these seals are likely to be the
source of emissions from compressors.
Shaft seals for compressors may be chosen from several
different types: labyrinth, restrictive carbon rings, mechanical
contact, and liquid film. All of these seal types are leak
restriction devices; none of them completely eliminate leakage.
2-29
-------
Many compressors may be equipped with ports in the seal area to
evacuate gases collecting there.
Safety Relief Devices. "Engineering codes require that
pressure-relieving devices or systems be used in applications
where the process pressure may exceed the maximum allowable
working pressure of the vessel. The most common type of
pressure-relieving device used in process units is the pressure
relief valve. Typically, safety relief valves are spring-loaded
and designed to open when the process pressure exceeds a set
pressure, allowing the release of vapors or liquids until the
system pressure is reduced to its normal operating level. When
the normal pressure is reattained, the valve reseats, and a seal
is again formed. The seal is a disk on a seat, and the
possibility of a leak through this seal makes the pressure relief
valve a potential source of emissions. Two potential causes of
leakage from safety relief valves are: "simmering or popping," a
condition due to the system pressure being close to the set
pressure of the valve, and improper reseating of the valve after
a relieving operation.
Open-Ended Lines. Some valves are installed in a system so
that they function with the downstream line open to the
atmosphere. Examples are purge valves, drain valves, and vent
valves. A faulty valve seat or incompletely closed valve would
result in leakage through the valve and emissions to the
atmosphere.
Sampling Connections. The operation of a process unit is
checked periodically by routing analyses of feedstocks and
products. To obtain representative samples for these analyses,
sampling lines must first be purged prior to sampling. The
purged liquid or vapor is sometimes drained onto the ground or
into a sewer drain, where it can evaporate and release emissions
to the atmosphere.
Flanges. Flanges are bolted, gasket-sealed junctions used
wherever pipe or other equipment such as vessels, pumps, valves,
and heat exchangers may require isolation or removal. Normally,
2-30
-------
flanges are employed for pipe diameters of 50 mm or greater and
are classified by pressure and face type.
Flanges may become emission sources when leakage occurs due
to improperly chosen gaskets or a poorly assembled flange. The
primary cause of flange leakage is due to thermal stress that
piping or flanges in some services undergo; this results in the
deformation of the seal between the flange faces.
Agitators. Agitators are technologically similar to pumps
and, like pumps, can be controlled using seal technology.
Although agitators have longer and larger diameter shafts than
pumps and produce greater tangential shaft loadings, the emission
factors used for calculating leaks from pumps are currently
acceptable for use in calculating leaks from agitators, due to
the lack of emissions data for agitators.
2.3.1 Accepted Techniques For Establishing HAP
Emissions From Equipment Leaks
There are five methods for establishing emissions from
equipment leaks. These methods, in increasing order of
complexity and accuracy, are:
• Average emission factor method;
Leak/no-leak emission factor method;
Three-strata emission factor method;
Application of EPA correlations; and
Development of new correlations.
A detailed discussion of the above methods is presented in
the EPA report Protocols for Generating Unit-Specific Emission
Estimates for Equipment. Leaks of VOC and VHAP.8 All methods
start with obtaining an accurate identification and count of
equipment to be included. The equipment counts can simply be
used with the EPA's previously developed emission factors. The
next step in complexity and refinement is the use of a portable
organic analyzer to find the number of leaking and nonleaking
2-31
-------
sources. Leaking and nonleaking emission factors developed by
the EPA can then be applied to generate the emissions. These
factors are presented in Table 2-14.
A final refinement is a method employing discrete emission
factors. In this approach emission factors are applied to
represent three different ranges of screening values. This has
been called the stratified emission factor approach, or.the
three-strata approach. Applying the stratified emission factors
requires more rigorous measurement of organic vapor
concentrations with a portable instrument because actual
concentration readings must be recorded instead of noting whether
a piece of equipment is classified as leaking or not leaking.
stratified emission factors developed by the EPA can then be
applied to generate the emission estimate. These factors are
presented in Table 2-15.
The remaining two methods make use of correlations relating
mass emissions to organic concentrations measured with a portable
organic analyzer. The EPA's previously developed correlations
are offered for use, and finally, if a process unit's emissions
are statistically different from those represented by the EPA's
correlations, provision is made for development of correlations
specifically for that process unit.
For the purpose of establishing emission levels for the
early emission reduction program, EPA does not consider the
average emission factor method to be appropriate. These emission
factors were based on data from process units with a wide range
of equipment leak frequencies. A given process unit may not have
leak frequencies similar to the average leak frequencies of these
process units. The application of these factors could,
therefore, result in erroneous emission estimates.
The other four emission estimate methods are considered
acceptable for the purpose of establishing baseline emissions.
The most accurate estimates are obviously made through
development of new correlations. However, requiring the use of
2-32
-------
TABLE 2-14.
LEAKING AND NON-LEAKING EMISSION FACTORS FOR
FUGITIVE EMISSIONS (kg/yr/source)a
Equipment
Service
Leaking
(>10,000 ppmv)
Emission Factor
Non Leaking
(<10,000 ppmv)
Emission Factor
Valves
Pump Seals
Compressor Sealsd
Pressure Relief
Gas /Vapor*3
Light liquid
Heavy liquid
Light liquid
Heavy liquid
Gas /Vapor
Gas/Vapor
0.0451
0.0852
0.00023°
0.437
0.3885
1.608
1.691
0.00048
0.00171
0.00023
0.0120
0.0135
0.0894
0.0447
• Valves
Flanges
Open-Ended Lines
All
All
0.0375
0.01195
0.00006
0.00150
aReference 8 .
The leaking and non-leaking emission factors for valves in
gas/vapor service are based upon the emission factors determined
for gas valves in ethylene, cumene, and vinyl acetate units
during the SOCMI Maintenance Study.
GLeaking emission factor assumed equal to non-leaking emission
factor since the computed leaking emission factor
(0.00005 kg/hr/source) was less than the non-leaking emission
factor.
dEmission factor reflects existing control level of 60 percent
found in the industry; control is through the use of barrier
fluid/degassing reservoir/vent-to-flare or other seal leakage
capture system.
2-33
-------
TABLE 2-15.
STRATIFIED EMISSION FACTORS FOR EQUIPMENT LEAKSa
(kg/hr/source)
Source
Service
Emission Factors (kg/yr/source)
for Screening Value Range, ppmv
0-1,000 1,001-10,000 >10,000
Compressor
Sealsd
Pump seals
Valves
Flanges,
connections
Pressure
Relief
devices
Open-ended
Lines
Gas/vapor
Light liquid
Heavy liquid
Gas/vapor13
Light liquid
Heavy liquid
All
Gas/vapor
All
0.01132
0.00198
0.00380
0.00014
0.00028
0.00023C
0.00002
0.0114
0.00013
0.264
0.0335
0.0926
0.00165
0.00963
0.00023°
0.00875
0.279
0.00876
1.608
0.437
0.3885
0.0451
0.0852
0.00023
0.0375
1.691
0.01195
aReference 8.
bThe leaking and non-leaking emission factors for valves in
gas/vapor service are based upon the emission factors determined
for gas valves in ethylene, cumene, and vinyl acetate units
during the SOCMI Maintenance Study.
cLeaking emission factor assumed equal to non-leaking emission
factor since the computed leaking emission factor
(0.00005 kg/hr/source) was less than the non-leaking emission
factor.
dEmission factor reflects existing control level of 60 percent
found in the industry; control is through the use of barrier
fluid/degassing reservoir/vent-to-flare or other seal leakage
capture system.
2-34
-------
this method can be costly and may discourage many facilities from
pursuing the early emission reduction program.
The leak/no-leak emission factor method, while a significant
improvement over the average emission factor method, may yield
estimates that are not completely accurate. However, these
estimates are considered to be within reasonable ranges of
accuracy. In addition, many facilities are expected to have
leak/no-leak frequency data already available which may encourage
them to implement an early emission reduction program.
2.3.2 Documentation of HAP Emissions From Equipment
Leaks
The documentation requirements discussed in this section
relate to the leak/no leak emission factor method. If a facility
chooses to use one of the more refined methods, the documentation
requirements will be considered on a case by case basis.
For the leak/no leak or stratified method, the following
information should be provided along with the computed emissions:
Equipment count by equipment type (i.e., vapor valves,
liquid valves, etc.),
Period during which screening was conducted,
• A description of any deviations from EPA Method 21
procedures,
Percent of sources found leaking (by source type) or
measured concentration,
HAP content as percent of VOC,
Number of sources in facility that were considered
difficult to monitor and not screened.
Forms for reporting this information and computing baseline
emissions are provided in Appendix A for both the leak/no leak
approach and the stratified emission factor approach.
2.4 TRANSFER OPERATIONS
2-35
-------
Loading losses are the primary source of evaporative
emissions from rail tank car, tank truck and marine vessel
transfer operations. Loading losses occur as organic vapors in
"empty" cargo tanks are displaced to the atmosphere by the liquid
being loaded into the tanks. These vapors are a composite of (1)
vapors formed in the empty tank by evaporation of residual
product from previous loads, (2) vapors transferred to the tank
in vapor balance systems as product is being unloaded, and (3)
vapors generated in the tank as the new product is being loaded.
The quantity of evaporative losses from loading operations is,
therefore, a function of the following parameters.
• Physical and chemical characteristics of the previous
cargo,
• Method of unloading the previous cargo,
• Method of loading the new cargo, and
Physical and chemical characteristics of the new cargo.
The three principal loading methods are splash loading,
submerged loading, and vapor balance loading. In the splash
loading method, the fill pipe dispensing the cargo is lowered
only partway into the cargo tank. Significant turbulence and
vapor/liquid contact occur during the splash loading operation,
resulting in high levels of vapor generation and loss. If the
turbulence is great enough, liquid droplets will be entrained in
the vented vapors.
A second method of loading is submerged loading. Two types
are the submerged fill pipe method and the bottom loading method.
In the submerged fill pipe method, the fill pipe extends almost
to the bottom of the cargo tank. In the bottom loading method, a
permanent fill pipe is attached to the cargo tank bottom. The
fill pipe opening is below the liquid surface level, during most
of the loading operation. Liquid turbulence is controlled
significantly, resulting in much lower vapor generation than
encountered during splash loading.
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The recent loading history of a cargo carrier is just as
important a factor in loading losses as the method of loading.
If the carrier has carried a ^nonvolatile liquid such as fuel oil,
or has just been cleaned, it will contain vapor free air. If it
has just carried a volatile HAP and has not been vented, the air
in the carrier tank will contain volatile organic vapors, which
are expelled during the loading operation along with newly
generated vapors.
Cargo carriers are sometimes designated to transport only
one product, and in such cases are practicing "dedicated
service". Dedicated cargo tanks return to a loading terminal
containing air fully or partially saturated with vapor from the
previous load. Cargo tanks may also be "switch loaded" with
various products, so that a nonvolatile product being loaded may
expel the vapors remaining from a previous load of a volatile
product. These circumstances vary with the type of cargo tank
and with the ownership of the carrier, the petroleum liquids
being transported, geographic location, and season of the year.
One control measure for tank truck loading is called "vapor
balance service", in which the cargo tank retrieves the vapors
displaced during product unloading, and transports the vapors
back to the loading terminal. A cargo tank in vapor balance
service normally is saturated with organic vapors, and the
presence of these vapors at the start of submerged loading
results in greater loading losses than encountered during
nonvapor balance, or "normal", service. Vapor balance service is
usually not practiced with marine vessels, although some vessels
practice emission control by means of vapor transfer within their
own cargo tanks during ballasting operations.
2.4.1 Accepted Techniques for Establishing Emissions from
Transfer Operations
Emissions of each HAP can be established using the following
expression for each type of loading operation:9
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LL = 5.65E-03 SPMG
T
where: LL = loading loss, Mg/yr,
M = molecular weight of the HAP, Ib/lb-mole
P = true vapor pressure of the HAP loaded, psia
G = annual volume of liquid loaded, gallons,
T = temperature of bulk liquid loaded, °R (°F +
460),
S = saturation factor (see Table 2-16)
The saturation factor, S, represents the expelled vapor's
fractional approach to saturation, and it accounts for the
variations observed in emission rates from the different
unloading and loading methods. Table 2-16 lists the saturation
factors for various cargo vessels and modes of operation.
In cases where the HAP is part of a mixture rather than a
pure component, the partial pressure of the HAP should be used in
place of the pure component vapor pressure. For mixtures where
the HAP concentration is greater than 1 percent by volume,
Raoult's Law is deemed appropriate for computing the partial
pressure. For mixtures where the -HAP concentration is less than
1 percent, Henry's Law is deemed appropriate for computing the
partial pressure.
Total HAP emissions from loading are computed by summing the
loading losses of individual HAPs from each material loaded via
each loading method. In cases where numerous materials are
loaded during the year by various loading techniques (i.e.,
submerged fill, splash fill, vapor balance), it is important that
the HAP emissions are calculated separately for each set of
conditions and then summed.
2.4.2 Documentation of HAP Emissions From Loading
Operations
Loading operation characteristics, volumes loaded into each
vessel type, and the HAP physical property data used to perform
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TABLE 2-16. SATURATION (S) FACTORS FOR CALCULATING
ORGANIC LIQUID LOADING LOSSES3
Cargo Carrier
Mode of Operation
S Factor
Tank trucks and
rail tank cars
Marine vessels
Submerged loading
of a clean cargo
tank
Submerged loading:
dedicated normal
service
Submerged loading:
dedicated vapor
balance service
Splash loading of
a clean cargo tank
Splash loading:
dedicated normal
service
Splash loading:
dedicated vapor
balance service
Submerged loading:
ships
Submerged loading:
barges
0.50
0.60
1.00
1.45
1.45
1.00
0.2
0.5
aReference 9 .
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loading operation emission calculations should be provided for
each material/vessel type. A set of forms listing the required
computation inputs is provided in Appendix A. The form provided
in Appendix A should be completed and submitted for each
combination of material loaded, cargo carrier, and mode of
operation.
2 . 5 WASTEWATER COLLECTION AND TREATMENT
In the manufacture of chemical products, wastewater streams
are generated which contain volatile organics. These wastewaters
are collected and treated in a variety of ways. Some of these
collection and treatment steps result in the emission of volatile
organics from the wastewater into the ambient air. This
subsection provides a discussion of the potential sources of
emissions during wastewater collection and treatment, and
techniques for establishing air emissions from wastewater
sources.
The industries covered by the Hazardous Organic NESHAP
differ in structure and manufacture a wide variety of products.
However, many of the chemical processes employed within these
industries use similar organic compounds as raw materials,
solvents, catalysts, and extractants. In addition, many of these
processes also generate similar organic by-products during
reaction steps. Consequently, many of the wastewater streams
generated by the targeted industries are similar in organic
content. These organic containing wastewater streams result from
both the direct and indirect contact of water with organic
compounds.
Water comes in direct contact with organic compounds due to
many different chemical processing steps. As a result of this
contact, wastewater streams are generated which must be
discharged for treatment or disposal. A few sources of process
wastewater are:10
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• Water used to wash impurities from organic products or
reactants;
• Water used to cool-or quench organic vapor streams;
• Condensed steam from jet eductor systems pulling vacuum
on vessels containing organics;
• Water used as a carrier for catalysts and neutralizing
agents (e.g., caustic solutions); and
• Water formed as a by-product during reaction steps.
Two additional types of direct contact wastewater are
landfill leachate and water used in equipment washes and spill-
cleanups. These two types of wastewater are normally more
variable in flow and concentration than the streams previously
discussed. In addition, landfill leachate and spill cleanups may
be collected for treatment differently than the wastewater
streams discharged from process equipment such'as scrubbers,
decanters, evaporators, distillation columns, reactors, and
mixing vessels.
.Wastewater streams which do not come in contact with organic
compounds in the process equipment are defined as "indirect-
contact" wastewater. However, a potential exists for organic
contamination of these wastewater types. Water streams which are
contaminated as a result of leaks from heat exchangers,
condensers and pumps (pump seal water) are examples of non-
contact wastewater. These indirect contact wastewaters may or
may not be collected and treated in the same manner as direct
contact wastewaters. Pump seal water is normally collected in
area drains which tie into the process wastewater collection
system. This wastewater is then combined with direct contact
wastewater and transported to the wastewater treatment plant.
Wastewater contaminated from condenser and heat exchanger leaks
are often collected in different systems and bypass some of the
treatment steps used in the treatment plant.
Wastewater streams are collected and treated in a variety of
ways. Generally, wastewater passes through a series of
collection and treatment units before being discharged from a
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facility. Table 2-11 presents a list of components that may be
sources of emissions in facility collection and treatment
systems. Many of these collection and treatment system units are
open to the atmosphere and allow organic-containing wastewaters
to contact ambient air. Whenever this happens, there is a
potential for air emissions. The organic pollutants volatilize
in an attempt to exert their equilibrium partial pressure above
the wastewater. In doing so, the organics are emitted to the
ambient air surrounding the collection and treatment units. The
magnitude of emissions depends greatly on many factors such as
the physical properties of the pollutants, the temperature of the
wastewater, and the design of the individual collection and
treatment units. All of these factors as well as the general
scheme used to collect and treat facility wastewater have an
effect on air emissions.
2.5.1 Accepted Techniques for Establishing HAP
Emissions From Wastewater Collection and Treatment
The accepted approach for establishing emissions from
wastewater sources is direct measurement of the volatile organic
HAP content and measurement or estimation of the wastewater flow.
However, considering the expense of sampling and analysis, only
those streams with average annual flows greater than 10 liters
per minute (1pm) must be sampled. A more detailed description of
the accepted approach is provided below.
Identification of wastewater sources. The- first step
towards establishing emissions from wastewater sources is the
identification of all wastewater streams within the process or
facility. As described above, there are two general types of
organic containing wastewaters: direct contact and indirect
contact. In general direct contact wastewaters account for the
majority of HAP loadings in facility wastewaters. Therefore, the
focus should be on direct contact process wastewater streams.
Examples of direct contact wastewater streams are water used to
wash impurities from organic reactants or products; water formed
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TABLE 2-17. EMISSION SOURCES IN WASTEWATER COLLECTION
AND TREATMENT SYSTEMS3
Wastewater Collection System:
Drains
Junction Boxes
Lift Stations
Manholes
Trenches
Sumps
Surface Impoundments
Wastewater Treatment Units:
Weirs
Oil/Water Separators
Equalization Basins or Neutralization Basins
Clarifiers
Aeration Basins
pH Adjustment Tanks
Flocculation Tanks
aReference 10.
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as a reaction by-product; water used as a carrier for catalyst,
reactants, oxidizing agents, or neutralizing agents; and steam
jet vacuum condensates. These wastewater streams may be
discharged to the wastewater collection system from scrubbers,
decanters, distillation columns, or reactors.
In identifying wastewater streams, it is important to
identify the wastewater stream at the point of generation, prior
to contact with ambient air and prior to mixing with other .
Since volatilization of HAPs in the wastewater occurs upon
contact with ambient air, the point of generation represents the
point at which the greatest emission potential exists. In most
cases, the first point of atmospheric exposure is when the
wastewater stream is discharged into the process area sewer
'system. These sewer systems are typically underground, but are
open to the atmosphere.
Measurement of stream flow and concentration. After
identifying all facility or process wastewater streams, both
continuous and intermittent, the next step is to either measure
or estimate the average flowrate (annual basis). This must be
done for each wastewater stream, at the point of generation. In
cases where measurement is not feasible, an average annual flow
rate can be estimated based on engineering calculations such as
heat and material balances.
It is preferable to measure the HAP concentration of each
stream. However, calculations based on engineering principles or
material balance data are acceptable in situations where:
(1) No applicable EPA Reference Method, EPA Conditional
Method, or other source test method exists;
(2) It is not technically or economically feasible to
perform source tests;
(3) It can be demonstrated to the satisfaction of the
reviewing agency that the calculation will provide
emission estimates of accuracy comparable to any
applicable source test method;
(4) The base year conditions no longer exists and cannot be
reproduced and testing under the current conditions and
extrapolating will not produce results more accurate
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than an estimate base on engineering principles or
material balance; or
(5) The emissions from-one or a set of emission points in
the source are small compared to total source emissions
and errors in estimating emissions from such points
will not have a significant effect on the accuracy of
estimated total emissions from the source.
The burden of adequately demonstrating one of these reasons for
not source testing is placed on the source owner or operator.
If source tested, a representative grab sample of each
stream should be obtained at the point of generation. It is
important that the sample be taken at a time representative of
normal flow. Additionally, attempts should be made to collect a
sample representative of average annual concentrations. In the
case of highly variable flow and concentration, a sufficient
number of samples need to be taken to characterize the stream
with respect to a flow-weighted annual average.
Each sample should be collected and analyzed using EPA
Method 25D in combination with Method 18. Method 25D is a method
developed specifically for quantifying the organic emission
potential of a wastewater stream. Since Method 25D was developed
for VOC quantification, the analytical instruments employed are a
flame ionization detector (FID) and halogen detector. Specific
HAP concentrations can be quantified by running Method 18 on the
vent stream by replacing the FID/halogen detector with a gas
chromatograph and following the procedures prescribed in
Method 18. It is important that the sampling and purge
procedures prescribed in Method 25 are followed.
In cases where all volatile organics suspected to be present
in the wastewater stream are HAPs, it is acceptable to use Method
25D alone. In this case, the measured VOC concentration is
accepted as the HAP concentration.
Compute emission potential. After both the average annual
flow and concentration have been determined for each stream, the
potential HAP emissions can be computed as:
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WES = 0.63 Q C H
1.67E07
where,
WES = potential emissions, Mg/yr,
Q = average flow rate during discharge, 1pm,
C = VO concentration as determined by Method 25
or HAP concentration as determined by Method
25D/Method 18, mg/1, and
H = annual hours of stream flow, hrs
0.63 = Theoretical factor to account for the
fraction of HAP that would potentially
volatilize during collection and
treatment .-1-1
Notice that the term "potential" emissions is used. A
number of factors can affect the fraction of HAP which is
volatilized during collection and treatment. However, it is not
feasible to prescribe a method that takes all factors into
account.
Since Method 25D is a recently developed method, most
existing concentration data were developed using other analytical
methods. Method 25D is clearly the preferred method for sampling
and analysis. However, concentration data developed via EPA
Method 624, SW 846, and CARB Method 401 are acceptable for years
prior to 1991. In such cases, the following equation should be
used to compute HAP emissions:
WES = [Q H C (1.061 + 6.54E-02 * In(HLaw)]/I.67E07
where, HLaw = Henry's Law Constant (atm m3/g-mole)
The total HAP emissions from wastewater sources is computed
by simply summing the potential emissions of individual streams.
2.5.2 Documentation of HAP Emissions From Wastewater
Sources
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In establishing HAP emissions from wastewater sources, the
following information should be provided with the computed
emission rate for each stream:
• Stream identification,
• Stream flow rate, method of measurement, and date of
measurement,
• Stream discharge temperature,
• Stream HAP concentration, method of measurement, and
date of measurement, and
• A statement that the measured flow and concentration
are believed to be representative of normal operation.
The form provided in Appendix A should be completed and submitted
for each wastewater stream.
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REFERENCES
1. U.S. Environmental Protection Agency, Office of Research and
Development. Protocol for the Field Validation of Emission
Concentrations from Stationary Sources. EPA Publication No.
450/4-90-015. Research Triangle Park, North Carolina.
April 1990.
2. U.S. Environmental Protection Agency, Office of Air quality
Planning and Standards. Estimating Air Toxics Emissions
From Organic Liquid Storage Tanks. EPA Publication No.
EPA-450/4-88-004. Research Triangle Park, North Carolina.
October 1988.
3. U.S. Environmental Protection Agency, Office of Air Quality
Planning and Standards. VOC Emissions from Volatile Organic
Liquid Storage Tanks—Background Information for Proposed
Standards. EPA-450/3-81-003a.
4. American Petroleum Institute. Evaporative Loss From
External Floating-Roof Tanks. API Publication 2517
Washington, D.C. February 1989.
5. U.S. Environmental Protection Agency, Office of Air Quality
Planning and Standards. Guideline Series: Control of
Volatile Organic Liquid Storage in Floating and Fixed Roof
Tanks. EPA 450/3-84-005. Research Triangle Park, NC
July 1984.
6. U.S. Environmental Protection Agency. VOC Fugitive
Emissions in Synthetic Organic Chemical Manufacturing
Industry - Background Information for Proposed Standards
Publication No. 450/3-80-033a. Research Triangle Park, NC
November 1980.
7. U.S. Environmental Protection Agency. Control of Volatile
Organic Compound Leaks from Synthetic Organic Chemical and
Polymer Manufacturing Equipment - Guideline Series
Publication No. 450/3-83-006. Research Triangle Park, NC
March 1984.
8. U.S. Environmental Protection Agency. Protocols for
Generating Unit-Specific Emission Estimates for Equipment
Leaks of VOC and VHAP. Publication No. 450/3-88-010. '
Research Triangle Park, NC. October 1988.
9. U.S. Environmental Protection Agency, Office of Air Quality
Planning and Standards. Compilation of Air Pollutant
Emission Factors, Volume I: Stationary Point and Area
Sources. EPA-AP-42. Research Triangle Park, North
Carolina. September 1985. pp. 4.4-1 through 4.4-17.
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10. - U.S. Environmental Protection Agency. Industrial Wastewater
Volatile Organic Compound Emissions - Background Information
for BACT/LAER Determinations. Publication No.
EPA-450/3-90-04. Research Triangle Park, N.C. January
1990. pp 3-2 through 3-6.
11. Memorandum from Chuck Zukor, Radian Corporation, to Penny
Lassiter, EPA. Approach for Estimation of Emission
Reductions of HAPs from HON Model Wastewater Streams.
October 12, 1990. 7p.
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3.0 ESTABLISHING CHROMIUM EMISSIONS FROM CHROMIUM ELECTROPLATING
OPERATIONS
Chromium electroplating includes chromium electroplating and
chromic acid anodizing operations. Chromium electroplating is
the process by which chromium is electrochemically deposited from
a solution of chromic acid onto a metal or plastic part.
Conventional plating solutions contain 32 ounces of chromic acid
per gallon of water and a small amount of sulfuric acid or
fluoride compounds as a catalyst. In the chromium plating
process, the part to be plated is connected as the cathode in the
electrical circuit and lead alloys are typically used as the
anode. There are two types of chromium plating processes: hard
chromium plating and decorative chromium plating. In hard
chromium plating, a relatively thick layer of chromium (0.05 to
30 mils) is deposited directly on a base metal (usually steel) to
provide a surface with wear resistance, a low coefficient of
friction, hardness, and corrosion resistance. Hard chromium
plating is typically performed in stand alone plating tanks.
Hard plating also called functional plating is used for items
such as hydraulic cylinders and rods, industrial rolls, zinc die
castings, and marine hardware. In decorative plating, the base
material generally is plated with a layer of nickel followed by a
relatively thin layer (less than 0.1 mil) of chromium to provide
a bright tarnish resistant surface. Decorative chromium plating
is performed as the last step in a series of plating and metal
finishing operations. Decorative chromium plating is used for
items such as automotive trim, metal furniture, bicycles, hand
tools, and plumbing fixtures.
Emissions of chromic acid mist from the electrodeposition
of chromium in chromic acid plating baths occur because of the
inefficiency of the hexavalent chromium plating process; only
about 10 to 20 percent of the current applied actually is used to
deposit chromium on the item plated. Eighty to ninety percent of
3-1
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the current applied is consumed by the evolution of hydrogen and
oxygen gas at the cathode and anode with the resultant liberation
of gas bubbles. As the bubbles burst at the surface of the
plating solution, a substantial amount of fine chromic acid mist
is formed.
Numerous factors affect the amount of misting generated from
chromium plating tanks. These factors include: (I) current
density applied; (2) surface area of the part plated; (3) plate
thickness; and (4)' plating time. These factors are all
interrelated and are determined by using the electrochemical
equivalent of chromium, which is:
(Current, amperes)(Plating time, h) = 51.8 (3-1)
(Thickness, mil)(Surface area of part, ftz)
The electrochemical equivalent is derived from Faraday's
law. The equation above is based on a cathode efficiency of 100
percent and means that 51.8 ampere-hours are required to deposit
1 mil of chromium per square foot of part surface area. As
discussed previously, the cathode efficiency for actual chromium
plating baths is only 10 to 20 percent. The known variables in
the equation above for all platers are the surface area of the
part and the minimum plate thickness. The unknowns are then
calculated by modifing the equation to account for the actual
cathode efficiency. In the majority of cases, the plating time
is the factor that is adjusted to account for the lower cathode
efficiency. It is common practice to set the current based on a
current density of 2 amperes per square inch (A/in2) for hard
chromium plating and approximately 1 A/in2 for decorative
chromium plating. The low cathode efficiency means that 80 to 90
percent of the current supplied to the bath goes to form hydrogen
gas, which entraps the chromium solution. The amount of misting
then becomes directly proportional to the amount of current
supplied over a given time period. Therefore, hard chromium
plating operations tend to have higher emissions than decorative
3-2
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chromium plating operations because hard chromium plating is
performed at higher current densities and for longer periods of
time than decorative chromium plating operations.
Chromic acid anodizing is a process by which a film of
aluminum oxide is formed on the surface of aluminum
electrolytically to enhance the corrosion resistance of the part.
Chromic acid anodizing is used primarily for aircraft parts that
are subject to high stress and corrosive conditions.
Conventional anodizing solutions contain 7 to 8 ounces of chromic
acid per gallon of water. In chromic acid anodizing, the part is
connected as the anode in the electrical circuit instead of the
cathode as in chromium plating. Unlike the chromium plating
process, the anodizing process is a voltage controlled process
rather than a current controlled process. Voltage is applied to
the tank in a step-wise fashion until a level of 20 or 40 volts
is reached and is then maintained for the remainder of the
anodizing time (about 1 hour). Higher voltages are needed in
chromic acid anodizing than in chromium plating to overcome the
resistance of the oxide layer built up on the surface of the
aluminum. As in chromium plating, chromic acid emissions are
formed in the anodizing tank as a result of the evolution of
hydrogen and oxygen gas. The amount of gassing or chromium
misting decreases over the anodizing times as the current
decreases. In chromium plating, the amount of gassing or
chromium misting is constant over the plating time because the
current remains relatively constant. In general, emissions from
anodizing tanks are similar in magnitude to those measured at
decorative chromium plating facilities.
3.1 CONTROL TECHNIQUES/PERFORMANCE
The principal techniques used to control emissions of
chromic acid mist from chromium plating and chromic acid
anodizing operations include mist eliminators, wet scrubbers and
chemical fume suppressants.
3-3
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Chevron-blade and mesh-pad mist eliminators are the types of
mist eliminators most frequently used to control chromic acid
mist. The most important mechanism by which mist eliminators
remove chromic acid droplets from gas streams is the inertial
impaction of droplets onto a stationary set of blades or a mesh
pad. Mist eliminators typically are operated as dry units that
are periodically washed down with water to clean the impaction
media.
The wet scrubbers typically used to control emissions of
chromic acid mist from chromium plating and chromic acid
anodizing operations are single and double packed-bed scrubbers.
Other scrubber types used less frequently include fan-separator
packed-bed and centrifugal-flow scrubbers. The mechanism by
which scrubbers remove chromic acid droplets from the gas streams
is wetting the gas stream to increase the particles mass followed
by impingement on a packed bed. Once-through water or
recirculated water typically is used as the scrubbing liquid
because chromic acid is highly soluble in water.
Chemical fume suppressants are added to decorative chromium
plating and chromic acid anodizing baths to reduce chromic acid
mist. Although chemical agents alone are effective control
techniques, many plants use them in conjunction with a control
device. Chemical fume suppressants are surface-active compounds
that ar.e added directly to plating and anodizing baths to reduce
or control misting. Fume suppressants are classified as foam
blankets, wetting agents, and combinations of foam blankets and
wetting agents. Foam blankets are depleted mainly by dragout of
the plating solution and wetting agents are depleted mainly by
decomposition of the fume suppressant and, to a lesser extent, by
dragout of the plating solution. Wetting agents reduce misting
by lowering the surface tension of the plating or anodizing bath,
foam blankets reduce misting by entrapping the chromic acid mist
as it forms at the surface of the plating solution, and
combinations wetting agents/foam blankets reducing misting by
both methods. Fume suppressants are used widely by decorative
3-4
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chromium electroplaters. In contrast, hard chromium platers
seldom use fume suppressants. Fluorinated wetting agents have a
tendency to aggravate pitting, which affects the quality of the
hard chromium plate. Also, when foam blankets are used, there is
a potential for explosion of the entrapped hydrogen gas. These
tendencies are more pronounced in hard chromium plating than in
decorative chromium plating because of the higher current
densities and longer plating times associated with hard chromium
plating operations.
The performance capabilities of the control devices used to
control chromic acid mist were determined through an extensive
source test program. The general findings from the test program
were:
- Chevron-blade mist eliminators perform less well than
packed-bed scrubbers and mesh-pad mist eliminators.
- Packed-bed scrubbers perform marginally better than
mesh-pad mist eliminators.
- Fume suppressants are highly effective at eliminating
misting at decorative chromium plating operations.
The key finding from the test program was that all the
control devices performed as constant outlet devices.
Consequently, control efficiency is a poor indicator of
performance (unless the comparison is made at similar inlet
conditions). Therefore, the percent reduction values presented
in the following paragraph are based on representative inlet
conditions for each of the three processes.
The percent reduction of chevron-blade mist eliminators is
approximately 90 to 95 percent for hard chromium plating and
chromic acid anodizing operations (chevron-blade mist eliminators
are rarely used at decorative chromium plating operations). The
percent reduction for packed-bed scrubbers and mesh-pad mist
eliminators ranges from 97 to 99 percent with the higher percent
reductions being achieved at hard chromium plating operations
3-5
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where the inlet loadings are higher. For decorative chromium
plating operations, the percent reduction for fume suppressants
is greater than 99 percent if strict adherence to vendor
recommendations on the application of the fume suppressant are
followed.
3.2 ACCEPTABLE TECHNIQUES FOR ESTABLISHING EMISSIONS
The two acceptable approaches for determining emissions are
(1) Measurement - Measured hexavalent chromium mass
emission rate in stack gas.
(2) Emission Factors - Calculations based on average
measured emissions at numerous plating facilities.
Emission factors are expressed as milligrams of
hexavalent chromium per ampere-hour of current applied
for chromium plating operations or as milligrams of
hexavalent chromium per square meter of tank surface
area for chromic acid anodizing operations.
The preferred method for determining chromium emissions is
measurement of the mass emission rate using published EPA*
Methods. However, in some cases (as discussed in the following
sections), the use of process emission factors is acceptable for
determining baseline emissions.
Although the focus of this section is on establishing
emissions, it is important to keep in mind that the reason for
establishing baseline emissions is to enable the facility to
demonstrate early reductions. Therefore, consistent or at least
compatible methodologies should be used to establish baseline
emissions and emissions after control.
3-2.1 Hard Chromium Plating Operations
The preferred techniques for establishing baseline chromium
emissions from hard chromium plating operations is direct
measurement. Sample locations and gas stream characteristics
should be determined using EPA Methods 1, 2, and 4; and the
3-6
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hexavalent chromium concentration should be determined using
modified EPA Method 5. The Method 5 sampling train is modified
for chromium by eliminating the filter and using 0 . IN sodium
hydroxide in the impingers. The collected samples should be
analyzed for hexavalent chromium by using the diphenylcarbazide
colorimetric method. The chromium emission sampling method has
not been published in the Federal Register. For copies of the
draft method, please contact Mr. Frank Clay of the Emission
Measurement Branch at (919) 541-5236.
Establishing baseline chromium emissions for chromium
plating and anodizing tanks is basically the same for all three
processes. The following parameters are required through direct
measurement:
(1) volumetric flow rate of stack gas, dscmm
(2) hexavalent chromium concentration, mg/dscm
(3) operating hours per year for plating tank(s)
Annual baseline chromium emissions can then be calculated
using the following equation:
ER = (C) (Q) (60) (t)/1.0 x 109, (3-2)
where,
ER = annual chromium emissions, Mg/yr;
C = chromium concentration, mg/dscm;
Q = volumetric gas flow rate, dscmm; and
t = operating time, h/yr.
For operations where no control device was present prior to
1987, the application of a packed-bed scrubber is believed to be
an adequate demonstration of 95 percent control with no emission
testing required. The baseline emissions can be estimated using
process emission factors developed from the chromium
electroplating NESHAP source test data and published in the EPA
supplement to "Locating and Estimating Air Emission Sources of
3-7
-------
Chromium".1 For hard chromium electroplating operations, the
average process emission factor of 10 milligrams per ampere-hour
is recommended for use in establishing the baseline emissions.
The baseline emissions can be calculated using this factor in
either of the following equations:
ER = (PER) (C) (t)/1.0 x 109, or (3-3)
ER = (PER) (A)/1.0 x 109, (3-4)
where,
ER = annual emission rate, Mg/yr;
PER = process emission rate, mg/Ah;
C = average current applied to plating tank, amperes;
t = tank operating time, h/yr; and
A = -estimated ampere-hours applied in base year.
For operations where no control device was present in 1987
and a control technique, other than a packed-bed scrubber, was
applied to the operation, baseline emissions and the percent
reduction achieved by the control device would need to be
established through direct measurement of the inlet and outlet
chromium emission levels. The annual baseline emissions would
then be calculated by inputting the inlet chromium concentration
into Equation 3-2 . The percent reduction achieved by the control
device can be determined using the following equation:
% reduction = MR± - MRQ x 100 (3-5)
For facilities where there is a control device present and
the control device was present prior to 1987, the control device
efficiency should be accounted for in determining the baseline
emissions. To determine the annual baseline emissions, the
outlet chromium concentration should be measured and input into
3-J
-------
Equation 3-2. A 95 percent reduction over the annual baseline
emission rate would then need to be demonstrated.
3.2.2 Decorative Chromium Plating Operations
The preferred techniques for establishing baseline chromium
emissions from decorative chromium plating operations is direct
measurement. For an overview of the sampling methods and
analytical methods for chromium emission testing, please refer to
the Section 3.2.1 for hard chromium plating operations.
For operations where no control device was present prior to
1987, the application of a chemical fume suppressant or a packed-
bed scrubber is believed to be an adequate demonstration of 95
percent control with no emission testing required. The baseline
emissions can be estimated using process emission factors
developed from the chromium electroplating NESHAP source test
data and published in the EPA supplement to "Locating and
Estimating Air Emission Sources of Chromium".1 For decorative
chromium electroplating operations, the average process emission
factor of 2 milligrams per ampere-hour is recommended for use in
establishing the baseline emissions. The baseline emissions can
be calculated using Equations 3-3 or 3-4 given above.
For operations where no control device was present in 1987
and a control technique, other than chemical fume suppressants or
packed-bed scrubbers, was applied to the operation, baseline
emissions and the percent reduction achieved by the control
device would need to be established through direct measurement of
the inlet and outlet chromium emission levels. The annual
baseline emissions would then be calculated by inserting the
inlet chromium concentration into Equation 3-2. The percent
reduction achieved by the control device can be determined using
Equation 3-5.
For facilities where there is a control device present and
the control device was present prior to 1987, the control device
efficiency should be accounted for in determining the baseline
emissions. To determine the annual baseline emissions, the
3-9
-------
outlet chromium concentration should be measured and inputted
into Equation 3-2. A 95 percent reduction over the annual
baseline emission rate would then need to be demonstrated.
3-2.3 Chromic Acid Anodizing Operations
The preferred techniques for establishing baseline chromium
emissions from chromic acid anodizing operations is direct
measurement. For an overview of the sampling methods and
analytical methods for chromium emission testing, please refer to
the Section 3.2.1 for hard chromium plating operations.
For operations where no control device was present prior to
1987, the application of a chemical fume suppressant or a
packed-bed scrubber is believed to be an adequate demonstration
of 95 percent control with no emission testing required. The
baseline emissions can be estimated using process emission
factors developed from the chromium electroplating NESHAP source
test data and published in the EPA supplement to "Locating and
Estimating Air Emission Sources of Chromium".1 For chromic acid
anodizing operations, the average process emission factor of 0.6
grams per hour per square meter of tank surface area is
recommended for use in establishing the baseline emissions. The
baseline emissions can then be calculated by using the process
emission factor in the following equations:
ER = (PER) (SA) (t)/1.0 x 106, (3-6)
where,
ER = annual emission rate, Mg/yr;
PER = process emission rate, g/h/m2;
SA = surface area of plating tank(s), ft2; and
t = tank operating time, h/yr.
For operations where no control device was present in 1987
and a control technique, other than chemical fume suppressants or
packed-bed scrubbers, was applied to the operation, baseline
3-10
-------
emissions and the percent reduction achieved by the control
device would need to be established through direct measurement of
the inlet and outlet chromium emission levels. The annual
baseline emissions would then be calculated by inserting the
inlet chromium concentration into Equation 3-2. The percent
reduction achieved.by the control device can be determined using
Equation 3-5.
For facilities where there is a control device present and
the control device was present prior to 1987, the control device
efficiency should be accounted for in determining the baseline
emissions. To determine the annual baseline emissions, the
outlet chromium concentration should be measured and inserted
into Equation 3-2. A 95 percent reduction over the annual
baseline emission rate would then need to be demonstrated.
3-11
-------
REFERENCES
1. Locating and Estimating Air Emission Sources of
Chromium—Supplement. United States Environmental Protection
Agency, Research Triangle Park, North Carolina. EPA-450/2-89-
002. August 1989.
3-12
-------
4.0 ETHYLENE OXIDE STERILIZATION
Ethylene oxide (EO) is used as a sterilant/fumigant in the
production of medical equipment supplies, in miscellaneous
sterilization and fumigation operations, and at hospitals.
Practically all of the EO used in the steriliztion/fumigation
process is estimated to be emitted from three sources: (I) the main
sterilizer exhaust (i.e., the vent from the vacuum pump/liquid
separator), the aeration room or chamber, and the chamber exhaust
vent. Uncontrolled emissions from these sources are assumed to be
95, 3, and 2 percent of the EO use, respectively.
Available control techniques including acid scrubbers,
catalytic oxidizers, and flares can achieve emission reductions of
approximately 99%. Therefore, a 90% emission reduction of total EO
emissions can be achieved by controlling the main sterilizer
exhaust stream.
4.1 TECHNIQUES FOR ESTABLISHING BASELINE HAP EMISSIONS
For facilities without add-on controls, emissions are equal to
the amount of EO used in the sterilization chamber; an estimate of
annual EO use can be made by using annual inventory data.
Facilities with existing add-on controls must estimate the
effectiveness of the existing control system and estimate emissions
using the amount of EO used in the sterilization chamber.
4.2 TECHNIQUES FOR ESTABLISHING 90% HAP EMISSION REDUCTION
Uncontrolled Facilities
An emission mass-in/mass-out approach will be used to estimate
control efficiency for both catalytic oxidizers and scrubbers.
Tests should be run on an empty chamber.
4-1
-------
Mass-in
Mass into the control unit can be estimated by weighing the EO
supply cylinders before and after use to determine the amount of EO
in the chamber. Alternatively, mass in the chamber after evacuation
can be calculated by using concentration and chamber volume.
Concentration can be obtained by either using the ideal gas law or
a gas chromatograph. Mass into the control unit is the difference
between the EO charged to the chamber and the EO remaining in the
chamber. The test need be run only on the first evacuation cycle.
Mass-out
Mass out of the control unit is estimated by measuring flow
rate and EO concentration with EPA methods 2,2A,2C,or 2D and 18
respectively. For packed-bed scrubbers and catalytic oxidizers flow
rate and concentration can be measured directly. However, for a
reaction/detoxification tower, a flow must be induced to increase
the exit flow to a measureable rate.
Control Efficiency
The control efficiency is calculated by the following
equation:
Control Efficiency = (I - (MO/MI)) x 100
wnere MO = mass out of control device
MI = mass into control device
4-2
-------
APPENDIX A
CALCULATION WORKSHEETS FOR ESTABLISHING
BASE YEAR AND POST-REDUCTION HAP EMISSIONS
FROM SOCMI SOURCES
A-l
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM PROCESS VENTS
HAP: Date:
Year: Calculator;
Process Vent Identification:.
Description:
Process Conditions/Sampling
Date of flow measurement
Method of flow measurement
Date of concentration measurement
Method of concentration measurement
(if not an EPA Method give a brief
description and attach protocol)
Describe any problems encountered
during testing.
Production rate during flow determination (Ibs/hr)
Production rate during sampling (Ibs/hr)
Average production rate during base year (Ibs/hr)
Stream Characteristics
Average vent stream flow rate (ft3/min) = Q
HAP concentration (ppmv) = c
Annual hours of operation (hrs) = h
Vent stream discharge temperature (°F) = T
HAP molecular weight (Ib/lb-mole) = MW
HAP high-risk weighting factor =
^——^——^——
Control
Control device
HAP control efficiency ("%") ZZZZZZZZZ = eff
Calculationsa
Uncontrolled Emissions (Ey) = 3.94E-08 Q C h MW
T + 460
Uncontrolled Emissions (Ey) = 3. 94E-08 ( ) ( ) ( ) ( }_
+ 460
Mg/yr
HAP Emissions (E^^p) = Ey (I - eff/100)
A-2
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM PROCESS VENTS (CONCLUDED)
HAP Emissions
.(1 -
Mg/yr
7100)
Weighted HAP Emissions = EHAP
Weighted HAP Emissions = ( ) ( )
Mg/yr
If the conditions during testing are not representative of base
year operation, make the appropriate extrapolation below and
explain:
If the flow or concentration were not measured using an EPA
reference method, EPA conditional method or validated using
Method 301, provide justification and supporting calculations:
Expression provided in "Procedures for Establishing Base Year
and Post-Reduction HAP Emissions" to convert flow and
concentration into an annual mass rate; the 3.94E-08 constant is
based on the ideal gas law.
A-3
-------
Source :.
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM FIXED ROOF STORAGE TANKS
Date:
Year: Calculator:
Tank designation:
Product:
Tank Characteristics
Inside diameter, (ft) =D
Height, (ft) _H
O ^>B«^^miH^^^H>B^^_^M lint
Capacity, (gal) = n P. h * 7.48 qal / =v
4 ft3
if not known
Roof color __
Shell color
Vapor space height, (ft>a ~~ =H
Ambient Conditions
Average atmospheric pressure (psia) =Pa
(defaults 14.7 psia) " A
Average ambient diurnal temperature
rT,
• T
Average annual ambient temperature
(OF) *
Bulk Liquid Characteristics
Stored liquid temperature (°F)C =T
Total throughput per year (gal) =^S
Number of turnovers per yeard =NN
Molecular weight of vapor (Ib/lb mole) =M
Mole percent of HAP
Partial pressure of the HAP at liquid ZZZZZZZZIZIZ =P
conditions (psia)
HAP high-risk weighting factor =F
Adjustment Factors
Paint factor (see Table 2-3) =F
Small diameter tank factor6 ~~~~~~~ =C
Turnover factor^ _K
Product factor^ _ N
A-4
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM FIXED ROOF STORAGE TANKS (continued)
Control
Control device _ _
HAP control efficiency (%)
Calculations*1
Breathing Loss (M9/Yr) =
LB = 1.02E-05MV
= 1.02E-05(
0.68
P-P
0.68
)
D1.73H0.51AT0.50FpCKc
1.730.51 0 .50
Mg/yr
Working Loss (Mg/yr) = Lw = 1.09E-08 MVPVN%KC
= 1.09E-08 ( ) ( ) (
Mg/yr
=eff
Total Loss (Mg/yr) =
TL = LB + LW = (
) =
Mg/yr
If a control device is employed,
HAP Emissions (Ej^p) = Total Loss (1 - eff/100)
= (1 - /100)
Mg/yr
A-5
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM FIXED ROOF STORAGE TANKS (continued)
Weighted HAP Emissions = E
= (
alf vapor space height is unknown or shell, assume H equals one
half tank height. If tank has a cone roof, adjust vapor space
height by adding 1/3 of height of cone.
"If average ambient diurnal temperature change is unknown, assume
20°F.
GStored liquid temperature may be approximated from average
annual ambient temperature. See Table 2-2.
dN = AN
where N = number of turnovers per year
AN = total throughput per year (gal)
V = tank capacity (gal)
eFor D > 30ft, C=l; For 6 < D < 30ft, C=0.0771D-0.0013D2-0 .1334 .
fFor turnovers > 36, % = (180 + N)/(6 * N)
where KN = turnover factor (dimensionless)
N = number of turnovers per year
For turnovers < 36, % = 1
9KC = 1.0 for volatile organic liquids
"Expression for computing HAP emissions are from "Procedures for
Establishing Base Year and Post-Reduction HAP Emissions." The
calculation procedure is consistent with AP-42.
A-6
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM INTERNAL FLOATING ROOF STORAGE TANKS
HAP:
Year:
Tank designation:.
Product:
Date:
Calculator:
Tank Characteristics
Inside diameter,
Rim Seal type:.
(ft)
Number of columnsa
Effective column diameter (ft)50
Ambient Conditions
Average atmospheric pressure (psia)
Average annual ambient temperature
Bulk Liquid Characteristics
Stored liquid temperature (°F)
Total throughput per year (bbl/yr)
[Note: 42 gal/bbl]
Molecular weight of HAP (Ib/lb -mole)
True vapor pressure at bulk liquid
conditions (psia)
HAP liquid density (Ib/gal)
HAP high-risk weighting factor
Factors
Rim seal loss factor (Ib mole/ft yr) ;
obtain from Table 2-4
Product factor (dimensionless)
Shell clinage factor (bbl/1000 ft2);
obtain from Table 2-9
Deck fitting loss factor
Deck seam loss factor
(Ib-mole/ft yr)d
Deck seam length factor;
obtain from Table 2-7
= D
C
= P;
= T
= T,
Q
MV
= P
= F
HR
= KI
= K,
D
'D
A-7
-------
Source:___
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM INTERNAL FLOATING ROOF STORAGE TANKS (CONTINUED)
Control
Control device
HAP control efficiency T%1
Calculations6
P* = 0.068 P (1 + (1 - 0.068 P)0-5)2)
= 0.068 ( )/((! + (1 - 0.068 ( ))°-5)2) =
Lw = (0.943) OCWL [1
= (0.943) ( ) (
) ( ) ti + ( ) ( )1/2205 =
=eff
psia
LR = KR D P* MVKC/2205 = ( )(
)( )( )72205 =
LF = FF P* MVKC/2205 = ( )( )( )( )/2205 =
LD = KDFDD2 P* MVKC/2205 =
LT - LR + Lw + LF + LD =
Mg/yr
If a control device is employed,
HAP Emissions (E^j^p) = Total Loss (1 - eff/100)
= (1 - /100)
Mg/yr
/2205
A-J
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM INTERNAL FLOATING ROOF STORAGE TANKS (CONCLUDED)
aFor self-supported fixed roof or external floating roof tank,
Nc = 0. If Nc is unavailable, see Table 2-6.
blf Fc is unavailable;
Fc = 1.1 for 9 inch by 7 inch built-up columns;
0.7 for 8 inch diameter pipe column;
1.0 if column construction details are not known
CFF is determined using Table 2-10 and the following calculation
FF =
dKD =0.0 for welded deck and 0.34 for non-welded deck.
eExpression for computing HAP emissions are from "Procedures for
Establishing Base Year and Post-Reduction HAP Emissions." The
calculation procedure is consistent with AP-42 .
A-9
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM EXTERNAL FLOATING ROOF STORAGE TANK EMISSIONS
HAP:Date:
Year: Calculator:
Tank Designation:
Product:
Tank Characteristics
Inside tank diameter (ft) = D
Rim Seal Type: i
Tank color:
Ambient Conditions
Ambient temperature (°F)
Average windspeed for the tank site (mph) = V
Bulk Liquid Characteristics
Density of the HAP stored (Ib/gal) = WL
Molecular weight of the HAP (Ib/lb mol) = Mv
Ture vapor pressure of the HAP (psia) = P
HAP high-risk weighting factor = FHR
Factors
Seal factor; obtain from Table 2-8 = Ks
Seal windspeed exponent; obtain from
Table 2-8 = N
Product withdrawal shell clingage factor;
obtain from Table 2-9 = c
Product factor; 1.0 for VOL i.0 = KC
Total Roof Fitting Loss Factora = FF
Calculation
P* = 0.068P/((1 + (1 - 0.068P)0-5)2)
= 0.068( )/((! + (1 - 0.068( ))°-5)2)
psia
A-10
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM EXTERNAL FLOATING ROOF STORAGE TANK EMISSIONS (Cont.'d)
Calculations (cont.'d)
Withdrawal Loss = Lw = 4.28 x 10~4 QCWL/D
= 4.28 x 10~4 ( ) (
Mg/yr
Seal Loss = LSE = KSVNP*DMVKC/2205
Mg/yr
Roof Fitting Loss = FFP*MV.
Kc/2205
= ( ) ( ) (
) ( ) ( ) /2205
) (1.0) /2205
Mg/yr
Total Loss = Lrp = Lw + LgE + Lpp
= ( ) + ( ) + ( )
Mg/yr
Weighted HAP Emissions =
HP
Mg/yr
aFF is determined using Tables 2-11, 2-12, and 2-13 and the
following calculation:
FF =
A-ll
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM EQUIPMENT LEAKSa
HAP:_
Year:
Process:
Date:
Calculator:
Equipment Counts
Pump Seals (Light Liquid)
0 -10 wt% HAP of VOC
10-25 wt% HAP of VOC
25-75 wt% HAP of VOC
75-99 wt% HAP of VOC
100 wt% HAP of VOC
Pump Seals (Heavy Liquid)
0 -10 wt% HAP of VOC
10-25 wt% HAP of VOC
25-75 wt% HAP of VOC
75-99 wt% HAP of VOC
100 wt% HAP of VOC
Valves (Gas/Vapor)
0 -10 wt% HAP of VOC
10-25 wt% HAP of VOC
25-75 wt% HAP of VOC
75-99 wt% HAP of VOC
100 wt% HAP of VOC
Average
Total HAP
Number Wt. Fract
x
x
x
x
x
x
x
x
x
X
0.05
0.175 =
0.50
0.87
1.00
Subtotal
0.05
0.175 =
0.50
0.87
1.00
Subtotal
0.05
0.175 =
0.50
0.87
1.00
Subtotal
=PSLL
=PSHL
=VGV
Valves
0
10
25
75
10
(Light Liquid)
-10 wt% HAP of
-25
-Vb
-99
0
wt%
wt%
wt%
wt%
HAP
HAP
HAP
HAP
Of
Of
of
of
VOC
VOC
VOC
VOC
VOC
X
X
X
x
x
0
0
0
0
1
.05
.175 =
.50
.87
.00
Subtotal
=VLL
A-12
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM EQUIPMENT LEAKS (cont.'d)
Valves (Heavy Liquid)
0 -10 wt% HAP of
10-25
25-75
75-99
100
wt%
wt%
wt%
wt%
HAP
Of
HAP Of
HAP of
HAP Of
VOC
VOC
VOC
VOC
VOC
X
X
X
X
X
0
0
0
0
1
.05
. 1.75 =
.50
.87
.00
Subtotal
Pressure Relief Valves (Gas/Vapor)
0 -10 wt% HAP of VOC
10-25
25-75
75-99
100
wt%
wt%
wt%
wt%
HAP
HAP
HAP
HAP
Of
Of
Of
Of
VOC
VOC
VOC
VOC
X
X
X
X
X
0
0
0
0
1
.05
.175 =
.50
.87
.00
Subtotal
Open-Ended
0 -10
10-25
25-75
75-99
100
Lines
wt% HAP
wt% HAP
wt% HAP
wt% HAP
wt% HAP
Of
Of
of
of
of
VOC
VOC
VOC
VOC
VOC
X
X
X
X
X
0
0
0
0
1
.05
.175 =
.50
.87
.00
-
=VHL
=PRV
Subtotal =OEL
Compressor
0 -10
10-25
25-75
75-99
100
Sea:
wt%
wt%
wt%
wt%
wt%
Ls
HAP
of
HAP of
HAP of
HAP of
HAP of
VOC
VOC
VOC
VOC
VOC
X
X
X
X
X
0
0
0
0
1
.05
.175 =
.50
.87
.00
Subtotal
Sampling Connections
0 -10 wt% HAP of
10-25
25-75
75-99
100
wt%
wt%
wt%
wt%
HAP
HAP
HAP
HAP
of
of
of
of
VOC
VOC
VOC
VOC
VOC
X
X
X
X
X
0
0
0
0
1
.05
.175 =
.50
.87
.00
Subtotal
=CS
=SC
A-13
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM EQUIPMENT LEAKS (Stratified)(cont.'d)
Flanges
0 -10 wt% HAP of VOC x 0.05
10-25 wt% HAP of VOC x 0.175 =
25-75 wt% HAP of VOC x 0.50
75-99 wt% HAP of VOC x 0.87
100 wt% HAP of VOC _^_ x 1.00
Subtotal _ =F
Annual hours process equipment contains the HAP _ =H
Screening Calculations
Computed
Number of Sources Emissions50
Number _ Screening (ppmv) _ (per source)
Screened 0-1000 1000-lOQQO >1QQOQ kg/hr/source
Pump Seals
Light Liquid _ _ _ =E
Heavy Liquid _ _ ^Z --— - =E?SLL
Valves
Gas /Vapor _ _ _ _E
- -
Light Liquid _ =
Heavy Liquid _ _ ZHZ ZZZ - =EVLL
Pressure Relief Valves
Gas/Vapor _ _ _ _ _E
Open-Ended Lines _ _ =E
Compressor Seals _ _ =E
•™-"""^— •••• — M«__«^_ — •mW^^^B.B«B_«^_^ ^ ^
Sampling Connections _ _ _ =E
- - sc
Flanges _ _ _E
HAP Emission Calculation
PbLL,
PSHL
VGV
VLL
VHL
PRV
x
x
x
X
X
X
bPSLL
EPSHL
EVGV
EVLL
EVHL
EPRV
x
X
X
X
X
X
H =
H =
H =
H =
H =
H =
x
X
X
X
X
X
X =
X =
X =
X =
X =
x -
A-14
-------
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM EQUIPMENT LEAKS (Leak/No Leak)(cont.'d)
Screening Calculations"
Computed
Emissions3
Number Number Percent (per source)
Screened Leaking Leaking kg/hr/source
Pump Seals
Light Liquid = EPSLL
Heavy Liquid = EPSHL
Valves
Gas/Vapor = EVGV
Light Liquid = EVLL
Heavy Liquid = EVHL
Pressure Relief Valves
Gas/Vapor = EPRV
Open-Ended Lines = EOEL
Compressor Seals = ECS
Sampling Connections = E
sc
Flanges = EF
Baseline Emission Calculation
PSLL x EPSLL x H = x x =
PSHL x EPSHL x H = x x =
VGV x EVGV x H = x x =
VLL x EVLL x H = x x =
VHL x EVHL x H = x x =
PRV x EPRV x H = x x =
OEL x EOEL x H = x x =
CS x Ecs x H = x x =
SC x Esc x H = x x =
F x EF x H = x x =
Baseline Emissions = kg/yr
aCompute based on values provided in Table 2-11, using:
E = [LEF * PCL + NLEF * (100 - PCL)]/100
where: E = Emission per source; LEF = leaking emission factor;
NLEF = non-leaking emission factor; PCL = percent of sources
found leaking.
A-15
-------
Source:____
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM EQUIPMENT LEAKS (Stratified)(cont.'d)
HAP Emission Calculation (continued)
OEL x EOEL x H = x x =
CS x Ecs x H = x x =
SC x Esc x H = x x =
F x EF x H = x x = \
HAP Emissions (E^Ap) = kg/yr
HAP high-risk weighting factor
Weighted HAP Emissions = EHaD FH13
ilwfvtr ni\
= ( ) ( )
Kg/yr
Calculation worksheet and methodology from "Procedures for Establishing
Base Year and Post-Reduction HAP Emissions." This procedure is consistent
with the methodology presented in "Protocols for Generating Unit-Specific
Emission Estimates for Equipment Leaks of VOC and VHAP" (EPA Publication
No. 450/3-88-010) .
bCompute using the stratified emission factors provided in Table 2-12-
E = [ (NLi * SEFX) + (NL2 * SEF2) + (NL3 * SEF3) ] / (NL-. + NLo + NLo)
where: E = Emission per source; NLlf NL2, NL3 = number leaking in first
range, second range, and third range, respectively; SEFlr SEF2,
= stratified emission factor for first, second, and third range,
respectively.
A-16
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Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM LOADING OPERATIONS
HAP: Date:
Year: Calculator;
Loading Operation:
Loading Parameters
Cargo carrier (tank truck, rail car, etc.)
Mode of operation (choose from Table 2-16)
Annual volume of liquid loaded (gallons) = G
Temperature of liquid loaded (°F) = T
Weight percent HAP in the loaded material
True vapor pressure of the HAP loaded (psia) = p
[Note: For mixtures, use the HAP partial
pressure]
Molecular weight of the HAP (Ib/lb-mole) = M
Saturation factor (see Table 2-16) = s
HAP high-risk weighting factor = FHR
Control
Control device
HAP control efficiency (%) ZZ^ZZ^ZHZ = eff
Calculation5
Uncontrolled Loading Loss Eu = 5.65E-06 S P M G
T + 460
Uncontrolled Loading Loss Eu = 5.65E-06 ( ) ( ) ( ) (
( ) + 460
Mg/yr
HAP Emissions (E^^p) = Eu (1 - eff/100)
(1 - /100)
Mg/yr
A-17
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Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM LOADING OPERATIONS (CONCLUDED)
Calculation (continued)
Weighted HAP Emissions
Mg/yr
Calculation worksheet and procedure from "Procedures for
Establishing Base Year and Post-reduction HAP Emissions.1
This procedure is consistent with AP-42.
A-18
-------
Source:
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM WASTEWATER SOURCES
HAP: Date:
Year: Calculator:
Wastewater Stream Identification:.
Wastewater Stream Description:
Process Conditions/Sampling
Date of flow measurement _
Method of flow measurement _
Date of concentration measurement _
Method of concentration measurement _
Production rate during flow determination (Ibs/hr) _
Production rate during sampling (Ibs/hr) _
Average production rate during base year (Ibs/hr) _
Stream Characteristics
Average flow rate during discharge (1pm) _ = Q
HAP concentration (mg/1) _ = c
Annual hours of stream flow (hrs) _ .= H
HAP high-risk weighting factor _ = FHR
Control
Control device _
HAP control efficiency (%) ZZZZ^ZZH =
Calculationsa
Wastewater Emissions Potential (WEU) = 0.63 Q C H
1.67E07
Wastewater Emissions Potential (WE,,) = 0 .63 ( ) (
u>
1.67E07
Mg/yr
A-19
-------
Source: ___
CALCULATION WORKSHEET FOR ESTABLISHING HAP EMISSIONS
FROM WASTEWATER SOURCES (CONCLUDED)
Potential HAP Emissions
= WEU (1 - eff/100)
Weighted HAP Potential Emissions = E
= (
Hp
Calculation worksheet and procedure from "Procedures for
Establishing Base Year and Post-reduction HAP Emissions".
A-20
-------
TECHNICAL REPORT DATA
{Please read Instructions on the reverse before completing)
REPORT NO.
!PA-450/3-91-012a
2.
3. RECIPIENT'S ACCESSION NO.
TITLE AND SUBTITLE
Procedures for Establishing Emissions for Early
leduction Compliance Extensions - Volume 1
5. REPORT DATE
.Tnlv 1991
6. PERFORMING ORGANIZATION CODE
ALITHOR(S)
8. PERFORMING ORGANIZATION REPORT NO
PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
Environmental Protection Agency
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11 CONTRACT/GRANT NO.
2. SPONSORING AGENCY NAME AND ADDRESS
Office of Air Quality Planning and Standards
Environmental Proctection Agency
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Draft
14. SPONSORING AGENCY CODE
5. SUPPLEMENTARY NOTES
6. ABSTRACT
Regulations have been proposed governing compliance extensions for Early Reductions
of Hazardous Air Pollutants (HAP). The regulations allow a six year MACT standard
compliance extension for sources that achieve HAP reductions of 90% (95% for
particulates) from a base year of 1987 (or more recent base year). This document
includes acceptable emission estimating techniques that can be used when source
testing is not feasible. This document includes techniques "for synthetic organic
chemical manufacturing, ethylene oxide sterlization, and chromium electroplating.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
B.IDENTIFIERS/OPEN ENDED TERMS c. COSATI [-iclil'Group
Air Pollution Wastewater
Chromium Electroplating Loading Operatior
Ethylene Oxide Sterlization
Storage Tanks MACT Standard
Process Vents Compliance
Equipment Leaks
Air Pollution Control
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS i This Report/
Unclassified
90
20. SECURITY CLASS / This paeet
\ Unclassified'1", i 4
22 PRICE
EPA Form 2220-1 (R«v. 4-77)
PREVIOUS eoi TION i s OBSOLETE
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U.S. Environmental Protection Agency
Region 5, Library (p|_-12J)
77 West Jackson. Boulevard, 12th Floor
Chicago, a 60604-3590-
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