United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-453/R-97-010a \/
May 1997
Air
Hazardous Air Pollutant
Emissions from the Production
of Polyether Polyols--
Basis and Purpose Document
for Proposed Standards
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POLYETHER POLYOLS PRODUCTION
I)
Basis and Purpose Document
for Proposed Standards
Emission Standards Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
May 1997
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ENVIRONMENTAL PROTECTION AGENCY
Hazardous Air Pollutant Emissions from the Production of
Polyether Polyols - Basis and Purpose Document for Proposed
Standards
1. The standards regulate hazardous air pollutant
emissions from the production of polyether polyols.
Only polyether polyols production facilities that are
part of major sources under Section 112(d) of the Clean
Air Act (Act) will be regulated.
2. For additional information contact:
Mr. David Svendsgaard
Organic Chemicals Group
U.S. Environmental Protection Agency (MD-13)
Research Triangle Park, NC 27711
Telephone: (919) 541-2380
3. Paper copies of this document may be obtained from:
U.S. Environmental Protection Agency Library (MD-36)
Research Triangle Park, NC 27711
Telephone: (919) 541-2777
National Technical Information Service (NTIS)
5285 Port Royal Road
Springfield, VA 22161
Telephone: (703) 487-4650
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TABLE OF CONTENTS
1.0 INTRODUCTION 1
2.0 SUMMARY OF THE PROPOSED STANDARDS 2
2.1 The Source Category To Be Regulated 3
2.2 Relationship to Other Rules 4
2.3 Pollutants To Be Regulated 4
2.4 Affected Emission Points 4
2.5 Proposed Standards 4
3.0 RATIONALE FOR THE SELECTION OF POLLUTANT AND SOURCE
CATEGORY FOR CONTROL 24
4.0 RATIONALE FOR THE SELECTION OF THE EMISSION POINTS TO
BE COVERED BY THE PROPOSED STANDARDS 26
5.0 RATIONALE FOR THE SELECTION OF REGULATORY ALTERNATIVES
FOR EXISTING SOURCES 27
5.1 The Maximum Achievable Control Technology Floor
for Existing and New Sources 27
5.2 The Rationale for the More Stringent Regulatory
Alternative Considered for Existing Sources . 38
5.3 The Rationale for More Stringent the Regulatory
Alternatives Considered for New Sources .... 41
5.4 RATIONALE FOR THE SELECTION OF CONTROL LEVELS OF
THE PROPOSED STANDARDS 45
6.0 RATIONALE FOR THE SELECTION OF THE FORMATS OF THE
PROPOSED STANDARDS 48
6.1 Storage Vessels 48
6.2 Process Vents 49
6.3 Equipment Leaks 50
6.4 Wastewater Operations 50
7.0 RATIONALE FOR THE SELECTION OF COMPLIANCE AND
PERFORMANCE TEST PROVISIONS 51
7.1 Storage Vessels 51
7.2 Process Vents 52
7.3 Wastewater Operations 56
7.4 Equipment Leaks 57
8.0 RATIONALE FOR THE SELECTION OF MONITORING REQUIREMENTS
57
9.0 SELECTION OF RECORDKEEPING AND REPORTING REQUIREMENTS
59
10.0 OPERATING PERMIT PROGRAM 60
11
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SELECTION OF THE STANDARDS
1.0 INTRODUCTION
Section 112 of the Clean Air Act, as amended in 1990
(1990 Amendments) gives the EPA the authority to establish
national standards to reduce air emissions from sources that
emit one or more hazardous air pollutants (HAP).
Section 112(b) contains a list of HAP to be regulated by
National Emission Standards for Hazardous Air Pollutants
(NESHAP) , and Section 112 (c) directs the EPA to use this
pollutant list to develop and publish a list of source
categories for which NESHAP will be developed. The EPA must
list all known source categories and subcategories of "major
sources" that emit one or more of the listed HAP. A major
source is defined in section 112(a) as any stationary source
or group of stationary sources located within a contiguous
area and under common control that emits, or has the
potential to emit, in the aggregate, considering controls,
10 tons per year or more of any one HAP or 25 tons per year
or more of any combination of HAP. This list of source
categories was published in the Federal Register on July 16,
1992 (57 FR 31576), and includes polyether polyols
production as a category of major sources.
The end use of a polyether polyol is determined by the
properties of the polyol. Polyether polyols fall into two
main classifications: high-molecular-weight, linear or
slightly branched polyether polyols (urethanes), and low-
molecular-weight, highly branched polyether polyols (non-
urethanes). The linear or slightly branched polyether
polyols serve in flexible applications, such as in flexible
slab and molded foam, reaction injection molding, and in
other elastomer, sealant, and coating applications. The
branched polyether polyols serve in applications requiring
rigidity, such as rigid foams, solid or microcellular
plastic, and hard, solvent-resistant coatings.
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The purpose of this document is to provide the
rationale for the selection of the proposed standards for
the polyether polyols production source category. In order
to provide the background for subsequent discussions, the
first section of this document is a summary of the proposed
rule. This is followed by a discussion of the rationale for
the selection of various aspects of the standards, including
the source categories and pollutants to be regulated, the
level and format of the standards, and the compliance,
reporting, and recordkeeping provisions. The technical
memoranda presenting the background information for these
issues are presented in the Supplemental Information
Document (SID).
The format, reporting, recordkeeping and compliance
provisions of the proposed standards were primarily
established by the methods used to determine maximum
achievable control technology (MACT) floors and regulatory
alternatives for this source category. Because the EPA
decided to consider the Hazardous Organic National Emission
Standards for Hazardous Air Pollutants (HON) when
determining the MACT floors and regulatory alternatives for
polyether polyols production, the proposed standards for the
polyether polyol source category resemble the HON. The
rationale for the selection of the HON approach to determine
MACT floors and regulatory alternatives is provided in the
SID.
2.0 SUMMARY OF THE PROPOSED STANDARDS
This section provides a summary of the proposed
regulation. The full regulatory text is available in Docket
No. A-96-38, directly from the EPA, or from the Technology
Transfer Network (TTN) on the EPA's electronic bulletin
board. More information on how to obtain a copy of the
proposed regulation is provided in the preamble for the
proposed standards.
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2.1 The Source Category To Be Regulated
These proposed standards regulate HAP emissions from
polyether polyols manufacturing units (PMPU). Polyether
polyols are defined as the products formed by the reaction
of ethylene oxide (EO), propylene oxide (PO), or other
cyclic ethers with compounds having one or more reactive
hydrogens (i.e., a hydrogen atom bonded to nitrogen, sulfur,
oxygen, phosphorus, etc.). This definition excludes
materials regulated as glycols or glycol ethers under the
HON. For the proposed rule, an affected source is defined
as each group of one or more PMPU and located at a plant
site that is a major source.
The EPA decided it was appropriate to subcategorize the
source category for purposes of analyzing the MACT floors
and regulatory alternatives. The subcategories are
polyether polyols made from the polymerization of epoxides
and polyether polyols made from the polymerization of
tetrahydrofuran (THF). An "epoxide" is a chemical compound
consisting of a three-membered cyclic ether. Ethylene oxide
(EO) and propylene oxide (PO) are the only epoxides that are
listed as HAP. Subcategorization was necessary due to the
distinctively different nature of the epoxide and THF
processes and the effect of these differences on the
applicability of controls. One noteworthy distinction
between the two subcategories is that the first group,
polyols made with epoxides, uses HAP as the monomer(s),
whereas the second group does not use a HAP monomer.
Additionally, the first group performs the reaction
primarily on a batch basis, while the second group performs
the reaction on a continuous basis. Although the level of
the proposed standard is identical for wastewater, storage
vessels, and equipment leaks, the technical analyses were
conducted separately for each subcategory to determine the
appropriate level of the standard.
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2.2 Relationship to Other Rules
Sources subject to the proposed rule may also be
subject to other existing rules. Sources subject to the
proposed rule may currently have storage vessels subject to
the NSPS for Volatile Organic Liquid Storage Vessels (40 CFR
part 60, subpart Kb). After the compliance date for this
rule, such storage vessels are only subject to this rule and
are no longer required to comply with subpart Kb.
Sources subject to the proposed rule may have cooling
towers subject to the NESHAP for Industrial Cooling Towers
(40 CFR part 63, subpart Q). There is no conflict between
the requirements of subpart Q and the proposed rule.
Therefore, sources subject to both rules must comply with
both rules.
2.3 Pollutants To Be Regulated
Facilities in the source category covered by the
proposed rule emit a variety of HAP. The most significant
emissions are of the following HAP: EO, PO, hexane, and
toluene. These proposed standards would regulate emissions
of these compounds, as well as all other organic HAP that
are emitted during the production of polyether polyols.
2.4 Affected Emission Points
Emissions from the following types of emission points
(i.e., emission source types) are being covered by the
proposed rule: storage vessels, process vents, equipment
leaks, and wastewater operations.
2.5 Proposed Standards
The standards being proposed for the following emission
source types at new and existing facilities have the same
group determination criteria and control requirements as
those promulgated for the corresponding emission source
types at existing sources subject to the HON (Subpart F for
general requirements, Subpart G for process vents,
wastewater and storage vessels, and Subpart H for equipment
leaks): storage vessels; process vents from polyether
polyols made with THF; process vents from continuous unit
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operations that emit nonepoxide HAP while making or
modifying polyether polyols with epoxides; equipment leaks;
and wastewater.
A specified emission reduction for the combination of
all process vent streams within a PMPU is being proposed for
process vent epoxide emissions and for nonepoxide HAP
emitted from catalyst extraction. For process vents from
batch unit operations that emit nonepoxide HAP from the
making or modification of the product, this proposed
standard requires the Group I/Group 2 determination to be
based on the criteria in the Polymer and Resins I NESHAP.
In the event that there may be process vents from continuous
unit operations that emit nonepoxide HAP from the making or
modification of the product, this proposed standard requires
the Group I/Group 2 determination based on the criteria from
the HON.
Tables 1 and 2 summarize the level of control being
proposed for new and existing sources, respectively. Where
the applicability criteria and required level of control is
the same as the HON, this is indicated in the table as
"HON." When the table lists "epoxides," it is referring to
EO and PO, the HAP monomers used in the polyether polyols
process. "Nonepoxide HAP" refers to organic HAP other than
EO and PO that are used in the polyether polyols
manufacturing process. The following sections describe
these proposed standards in more detail, by emission source.
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2.5.1 Storage Vessels
For polyether polyols made with either epoxides or THF,
the storage vessel requirements at new and existing affected
sources are identical to the HON storage vessel requirements
in subpart G for existing sources. For this proposed rule,
a "storage vessel" is a tank or other vessel that is
associated with a PMPU and that stores a liquid containing
one or more organic HAP. The proposed rule specifies
assignment procedures for determining whether a storage
vessel is associated with a PMPU. The storage vessel
provisions do not apply to the following: (1) vessels
permanently attached to motor vehicles, (2) pressure vessels
designed to operate in excess of 204.9 kilopascals (29.7
pounds per square inch, absolute (psia)), (3) vessels with
capacities smaller than 38 cubic meters (m3) (10,000
gallons), (4) wastewater tanks, and (5) vessels storing
liquids that contain HAP only as impurities. An impurity is
produced coincidentally with another chemical substance and
is processed, used, or distributed with it. The owner or
operator must determine if the storage vessel is Group 1 or
Group 2; Group 1 storage vessels require control, while
Group 2 vessels do not. The criteria for determining
whether a storage vessel is Group 1 or Group 2 are shown in
Table 3, and are the same as the HON criteria for existing
sources.
TABLE 3. GROUP 1 STORAGE VESSEL CRITERIA
Vessel Capacity (cubic
meters)
Vapor Pressure3
(kilopascals)
Existing and new sources
75 <= capacity < 151
151 >= capacity
>= 13.1
>= 5.2
a Maximum true vapor pressure of total HAP at average
storage temperature.
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The storage provisions require that one of the
following control systems be applied to Group 1 storage
vessels: (1) an internal floating roof with proper seals and
fittings; (2) an external floating roof with proper seals
and fittings; (3) an external floating roof converted to an
internal floating roof with proper seals and fittings; or
(4) a closed vent system with a 95 percent efficient control
device. The storage provisions give details on the types of
seals and fittings required. Monitoring and compliance
provisions include periodic visual inspections of vessels,
roof seals, and fittings, as well as internal inspections.
If a closed vent system and control device are used, the
owner or operator must establish appropriate monitoring
procedures. Reports and records of inspections, repairs,
and other information necessary to determine compliance are
also required by the storage vessels provisions.
2.5.2 Process Vents
There are separate process vent provisions in the
proposed rule for the two polyether polyol subcategories.
Further, within the polyether polyol subcategory that
polymerizes epoxides, there are different emission limits
for different pollutants, and for different uses of the
organic HAP.
The process vent emissions from polyols made with
epoxides were divided into the following three groups:
epoxide emissions; nonepoxide HAP emissions from making or
altering the product, and; nonepoxide HAP emissions from
catalyst extraction.
2.5.2.1 Requirements for Epoxide Emissions
The process vent provisions for epoxide emissions
require the owner or operator of existing sources using
epoxides to reduce the aggregate total epoxide process vent
emissions by 98 weight-percent, and require the
owner/operator of new sources using epoxides to reduce the
aggregate total process vent emissions by 99.9 weight-
percent for new sources.
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As an alternative to requiring the owner or operator to
achieve the 98 (or 99.9) percent reduction using a
conventional control device, the proposed rule also allows
the owner or operator to use "extended cook-out" as a means
of reducing emissions by the required percentage. This
pollution prevention technique reduces emissions by
extending the time of reaction, thus leaving fewer unreacted
epoxides to be emitted downstream.
As an alternative to the 98 percent emission reduction,
owners or operators of existing sources may maintain an
epoxide emissions factor from the affected source no greater
than 1.7 X 10"2 kilograms of epoxide emissions per megagram
of product (kg/Mg). The corresponding epoxide emission
factor for new sources is 4.4 X 1CT3 kg/Mg. Compliance with
this alternative limitation will be achieved by developing
and following an epoxide annual emission factor plan, which
must include provisions for the monitoring of the process
and any control device parameters to demonstrate continuous
compliance with the emission factor limitation. A second
alternative to the 98 percent emission reduction for epoxide
emissions from existing sources is allowed. This
alternative emission limit is an epoxide concentration
cutoff of 20 parts per million by volume (ppmv) from the
outlet of a combustion, recapture, or recovery device.
2.5.2.2 Requirements for Nonepoxide HAP Emissions
from Catalyst Extraction
The process vent provisions require the owner or
operator of using epoxides to reduce the aggregate total
organic HAP emissions by 90 weight percent for existing
sources and 98 weight percent from process vents associated
with catalyst extraction for new sources. This provision
only applies if an organic HAP is used in the catalyst
extraction process.
2.5.2.3 Requirements for Nonepoxide HAP Used to Make
or Modify the Product
10
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There are separate provisions for process vents from
batch and continuous unit operations that use organic HAP to
make or alter the product. The approach for both batch and
continuous processes is to first determine the group status
for the collection of process vents in each PMPU that is
associated with the use of organic HAP to make or alter the
product. If the combination of vents is determined to be
Group 1, the aggregate organic HAP emissions are required to
be reduced by 90 percent for process vents from batch unit
operations and 98 percent for process vents from continuous
unit operations. These requirements are the same for new
and existing sources.
For process vents from batch unit operations, the Group
1 criteria are the same as the criteria in the Group 1
Polymers and Resins NESHAP, except that these criteria are
applied to the combination of all vents for the proposed
polyether polyol rule, and the criteria are applied to
individual vents in the Polymers and Resins rule. The Group
status is determined by calculating the annual emissions
from all of the applicable vents, and using these emissions
to calculate a "cut-off" flow rate. This cutoff flow rate
is then compared to the actual combined annual average flow
rate for all the vents. If the actual annual average flow
rate is less than the cutoff flow rate, the group of vents
is Group 1, and must be controlled by 90 percent.
For process vents from continuous unit operations, the
HON Group 1 criteria are used, except that they are applied
to the aggregated vent streams. The group of vents are
Group 1 if they have a total resource effectiveness index
value (TRE) less than or equal to 1.0.
The provisions for nonepoxide HAP emissions from making
or altering the product for continuous unit operations are
notably different than the provisions for the other
continuous process vent provisions in the proposed rule.
For the nonepoxide HAP emissions from making or altering the
product, the TRE of the combined vent streams is calculated
11
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after the final recovery device. Therefore, the recovery
device may be used to reduce emissions enough that the TRE
is increased and the combined stream becomes Group 2.
However, the recovery device may not be used to achieve the
required percentage reduction for the combination of process
vents that are Group 1.
Monitoring is required for the combination of process
vents from continuous unit operations that are Group 2, if
the combined stream characteristics result in a TRE index
value between 1.0 and 4.0. This monitoring is to ensure
that the combination of those streams do not become Group 1,
which would then require control.
For both batch and continuous unit operations, the
owner or operator can either make the Group I/Group 2
determination, or the owner or operator can elect to comply
directly with the Group 1 control requirements. For process
vents from continuous unit operations, the TRE index value
is determined after the final recovery device in the process
or prior to venting to the atmosphere. The TRE calculation
involves an emissions test or engineering assessment and use
of the TRE equations in §63.115 of subpart G.
Monitoring, reporting, and recordkeeping provisions
necessary to demonstrate compliance are also included in the
process vent provisions. These provisions are modeled after
the analogous process vent provisions in the HON.
Compliance with the monitoring provisions is based on a
comparison of batch cycle daily average monitored values to
enforceable parameter monitoring levels established by the
owner or operator.
2.5.2.4 Process Vent Requirements for Polyether
Polyols That Use THF as a Reactant
The proposed rule directly references the HON process
vent provisions in subpart G for polyether polyols processes
that use THF as a reactant. These provisions require a
Group I/Group 2 determination (on an individual vent basis),
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and the control of Group 1 process vent streams by 98
percent (or the use of a flare).
2.5.3 Wastewater Operations
For both polyether polyol subcategories, the proposed
wastewater provisions are identical to the wastewater
provisions in subparts F and G. The proposed rule applies
to water containing HAP, raw material, intermediate,
product, co-product, or waste material that exits any
polyether polyols production process unit equipment and has
either (1) a total organic HAP concentration of 5 ppmw or
greater and a flow rate of 0.02 liters per minute (1pm) or
greater; or (2) a total organic HAP concentration of 10,000
ppmw or greater at any flow rate. "Wastewater," as defined
in §63.101 of subpart F, encompasses both maintenance
wastewater and process wastewater. The process wastewater
provisions also apply to HAP-containing residuals that are
generated from the management and treatment of Group 1
wastewater streams. Examples of process wastewater streams
include, but are not limited to, wastewater streams exiting
process unit equipment (e.g., condenser stream decanter
water), feed tank drawdown, vessel washout/cleaning that is
part of the routine batch cycle, and residuals recovered
from waste management units. Examples of maintenance
wastewater streams are those generated by descaling of heat
exchanger tube bundles, cleaning of distillation column
traps, and draining of pumps into an individual drain
system.
2.5.3.1 Maintenance wastewater
For maintenance wastewater, the proposed rule
incorporates the requirements of §63.105 of subpart F for
maintenance wastewater. This requires owners or operators
to prepare a description of procedures that will be used to
manage HAP-containing wastewater created during maintenance
activities, and to implement these procedures.
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2.5.3.2 Process wastewater
The Group I/Group 2 approach from the HON is also used
for these proposed wastewater provisions, with Group 1
process wastewater streams requiring control and Group 2
process wastewater streams not requiring control. For
existing and new sources, a Group 1 wastewater stream is one
with a total annual average concentration of organic HAP
greater than or equal to 10,000 ppmw at any flow rate, or
with an average flow rate greater than or equal to 10 1pm
and a total organic HAP average concentration greater than
or equal to 1,000 ppmw.
An owner or operator may determine the organic HAP
concentration and flow rate of a wastewater stream either
(1) at the point of determination (POD); or (2) downstream
of POD. If wastewater stream characteristics are determined
downstream of the POD, an owner or operator must make
corrections for (1) losses by air emissions; (2) reduction
of organic HAP concentration or changes in flow rate by
mixing with other water or wastewater streams; and (3)
reduction in flow rate or organic HAP concentration by
treating or otherwise handling the wastewater stream to
remove or destroy HAP. An owner or operator can determine
the flow rate and organic HAP concentration for the POD by
(1) sampling; (2) using engineering knowledge; or (3) using
pilot-scale or bench-scale test data. Both the
applicability determination and the Group I/Group 2
determination must reflect the wastewater characteristics
before losses due to volatilization, a concentration
differential due to dilution, or a change in organic HAP
concentration or flow rate due to treatment.
There are instances in which an owner or operator can
bypass the group determination. An owner or operator is
allowed to designate a wastewater stream or mixture of
wastewater streams to be a Group 1 wastewater stream without
actually determining the flow rate and organic HAP
concentration for the POD. Using this option, an owner or
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operator can simply declare that a wastewater stream or
mixture of wastewater streams is a Group 1 wastewater stream
and that the emissions from the stream(s) are controlled
from the POD through treatment. Also, an owner or operator
who elects to use the process unit alternative in §63.138(d)
of subpart G or the 95-percent biological treatment option
in section 63.138(e) of subpart G is not required to make a
Group 1/Group 2 determination. However, the owner or
operator is required to determine the wastewater stream
characteristics (i.e., organic HAP concentration and flow
rate) for the designated Group 1 wastewater stream in order
to establish the treatment requirements in §63.138.
Controls must be applied to Group 1 wastewater streams,
unless the source complies with the source-wide mass flow
rate provisions of §§63.138(c)(5) or (c)(6) of subpart G; or
implements process changes that reduce emission as specified
in §63.138(c) (7) of subpart G. Control requirements include
(1) suppressing emissions from the POD to the treatment
device; (2) recycling the wastewater stream or treating the
wastewater stream to the required Fr values for each organic
HAP as listed in table 9 of subpart G (The required Fr
values in table 9 of subpart G are "fraction removed" (or
removal efficiency) based on a steam stripper, with
specified operating parameters, as the control technology);
(3) recycling any residuals or treating any residuals to
destroy the total combined HAP mass flow rate by 99 percent
or more; and (4) controlling the air emissions generated by
treatment processes. While emission controls are not
required for Group 2 wastewater streams, owners or operators
may opt to include them in management and treatment options.
Suppression of emissions from the POD to the treatment
device will be achieved by using covers and enclosures and
closed-vent systems to collect organic HAP vapors from the
wastewater and convey them to treatment devices. Air
emissions routed through closed-vent systems from covers,
enclosures, and treatment processes must be reduced by 95
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percent for combustion or recovery devices; or to a level of
20 ppmv for combustion devices.
The treatment requirements are designed to reduce the
organic HAP content in the wastewater prior to placement in
units without air emissions controls, and thus to reduce the
HAP emissions to the atmosphere. Section G of the preamble
provides several compliance options, including percent
reduction, effluent concentration limitations, and mass
removal.
For demonstrating compliance with the various
requirements, owners or operators have a choice of using a
specified design, conducting performance tests, or
documenting engineering calculations. Appropriate
compliance, monitoring, reporting, and recordkeeping
provisions are included in the regulation.
2.5.4 Equipment Leaks
The equipment leak provisions in the proposed rule
refer directly to the requirements contained in subpart H.
The standards would apply to equipment in organic HAP
service 300 or more hours per year that is associated with a
PMPU, including valves, pumps, connectors, compressors,
pressure relief devices, open-ended valves or lines,
sampling connection systems, instrumentation systems, surge
control vessels, bottoms receivers, and agitators. The
provisions also apply to closed-vent systems and control
devices used to control emissions from any of the listed
equipment.
2.5.4.1 Pumps and valves
This proposed standard requires leak detection and
repair (LDAR) for pumps in light liquid service and for
valves in gas or light liquid service. The proposed
standards for both will be implemented in three phases. The
first and second phases for both types of equipment consist
of an LDAR program, with lower leak definitions in the
second phase. The LDAR program involves a periodic check
for organic vapor leaks with a portable instrument; if leaks
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are found, they must be repaired within a certain period of
time. In the third phase, the periodic monitoring (a work
practice standard) is combined with a performance
requirement for an allowable percent leaking components.
The standard requires monthly monitoring of pumps using
an instrument and weekly visual inspections for indications
of leaks. In the first two phases of the valve standard,
quarterly monitoring is required. In phase three,
semiannual monitoring may be used by process units with less
than 1 percent leaking valves and annual monitoring may be
used by process units with less than 0.5 percent leaking
valves.
In phase three, if the base performance levels for a
type of equipment are not achieved, owners or operators
must, in the case of pumps, enter into a quality improvement
program (QIP), and, in the case of valves, may either enter
into a QIP or implement monthly LDAR. The QIP is a concept
that enables plants exceeding the base performance levels to
eventually achieve the desired levels without incurring
penalty or being in a noncompliance status. As long as the
requirements of the QIP are met, the plant is in compliance.
The basic QIP consists of information gathering, determining
superior performing technologies, and replacing poorer
performers with the superior technologies until the base
performance levels are achieved.
2.5.4.2 Connectors
The rule also requires LDAR for connectors in gas or
light liquid service. The monitoring frequency for
connectors is determined by the percent leaking connectors
in the process unit and the consistency of performance.
Process units that have 0.5 percent or greater leaking
connectors are required to monitor all connectors annually.
Units that have less than 0.5 percent may monitor biannually
and units that show less than 0.5 percent for two monitoring
cycles may monitor once every four years.
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2.5.4.3 Other equipment
Subpart H also contains standards for other types of
equipment, compressors, open-ended lines, pressure relief
devices, and sampling connection systems. Compressors are
required to be controlled using a barrier-fluid seal system,
by a closed vent system to a control device, or must be
demonstrated to have no leaks greater than 500 ppm HAP.
Sampling connections must be closed-purge or closed-loop
systems, or must be controlled using a closed vent system to
a control device. Agitators must either be monitored for
leaks or use systems that are better designed, such as dual
mechanical seals. Pumps, valves, connectors, and agitators
in heavy liquid service; instrumentation systems; and
pressure relief devices in liquid service are subject to
instrumental monitoring only if evidence of a potential leak
is found through sight, sound, or smell. Instrumentation
systems consist of smaller pipes and tubing that carry
samples of process fluids to be analyzed to determine
process operating conditions or systems for measurement of
process conditions.
Surge control vessels and bottoms receivers are
required to be controlled using a closed vent system vented
to a control device. However, the applicability of controls
to surge control vessels and bottoms receivers is based on
the size of the vessel and the vapor pressure of the
contents. The criteria for determining whether controls are
required for surge control vessels and bottoms receivers are
the same as for Group 1 storage vessels.
2.5.4.4 Other* equipment leak provisions
Under certain conditions, delay of repair beyond the
required period may be acceptable. Examples of these
situations include where: (1) a piece of equipment cannot be
repaired without a process shutdown, (2) equipment is taken
out of HAP service, (3) emissions from repair will exceed
emissions from delay of repair until the next shutdown, and
(4) equipment such as pumps with single mechanical seals,
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will be replaced with equipment with better leak
performance, such as dual mechanical seals.
In addition, specific alternative standards are
included for batch processes and enclosed buildings. For
batch processes, the owner or operator can choose either to
meet standards similar to those for continuous processes
with monitoring frequency pro-rated to time in use of HAP,
or to periodically pressure test the entire system. For
enclosed buildings, the owner or operator may forego
monitoring if the building is kept under a negative pressure
and emission are routed through a closed vent system to an
approved control device.
The equipment leak standards require the use of leak
detection instruments that meet the performance criteria in
Method 21 of appendix A of part 60. Method 21 requires a
portable organic vapor analyzer to monitor for leaks from
equipment in use. Test procedures using either a gas or a
liquid for pressure testing the batch system are specified
to detect for leaks.
The standards would require certain records to
demonstrate compliance with the standard, and the records
must be retained in a readily accessible recordkeeping
system. Subpart H requires that the following records be
maintained for equipment that would be subject to the
standards: information on the testing associated with batch
processes, design specifications of closed vent systems and
control devices, test results from performance tests, and
information required by equipment in the QIP.
2.5.5 Recordkeeping and Reporting Requirements
Specific recordkeeping and reporting requirements
related to each emission source type are included in the
applicable sections of the proposed rule. Section 63.1439
of the proposed rule provides general reporting,
recordkeeping, and testing requirements.
The general reporting, recordkeeping, and testing
requirements of this subpart are very similar to those found
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in subparts F and G. The proposed rule also incorporates
provisions of subpart A of part 63. A table included in the
proposed rule designates which sections of subpart A apply
to the proposed rule. This rule incorporates the March 16,
1994 promulgated General Provisions. However, the EPA is in
the process of drafting amendments to the General
Provisions. If this subpart is promulgated subsequent to
the promulgation of the amendments to the General
Provisions, the amended General Provisions will be
incorporated into this subpart.
The proposed rule requires sources to keep records and
submit reports of information necessary to determine
applicability and document compliance. The proposed rule
requires retention of hourly average values of monitored
parameters for continuous process vents. For batch process
vents, the proposed rule requires retention of daily average
values of monitored parameters. If there is a monitoring
parameter excursion for either batch or continuous process
vents, the 15-minute values for the excursion period must be
retained. The proposed rule also requires that records of
all residual HAP content test results must be kept for five
years.
Section 63.1439 of the proposed rule lists the
following types of reports that must be submitted to the
Administrator, as appropriate: (1) Start-up, shutdown, and
malfunction plan; (2) Application for Approval of
Construction or Reconstruction; (3) Initial Notification;
(4) Precompliance Report; (5) Notification of Compliance
Status; (6) Periodic Reports; (7) other reports; and (8)
Operating permit application. The requirements for each of
the eight types of reports are summarized below. This list
of reports in §63.1435 incorporates the reporting
requirements of subpart H: (1) An Initial Notification; (2)
a Notification of Compliance Status; and (3) Periodic
Reports.
2.5.5.1 Start-up, shutdown, and malfunction plan
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The plan would describe procedures for operating and
maintaining the affected source during periods of start-up,
shutdown, and malfunction and a program for corrective
action for malfunctioning process and air pollution
equipment used to comply with this subpart.
2.5.5.2 Application for Approval of Construction or
Reconstruction
For new affected sources, the proposed rule would
require the affected source to comply with the following
provisions from subpart A: §63.5(d)(1)(ii)(H), (d)(1)(iii),
(d)(2), and (d)(3)(ii) of subpart A.
2.5.5.3 Initial Notification
The Initial Notification is due 120 days after the date
of promulgation for existing sources. For new sources, it
is due 180 days before commencement of construction or
reconstruction, or 45 days after promulgation, whichever is
later. Owners or operators can submit one Initial
Notification to comply with both the requirements of section
63.1439 of the proposed rule and the requirements for
equipment leaks subject to subpart H. The notification must
list the processes that are subject to the proposed rule,
and which provisions may apply (e.g., storage vessels,
continuous process vents, batch process vents, wastewater,
and/or equipment leak provisions). A detailed
identification of emission points is not necessary for the
Initial Notification. The notification must, however,
include a statement of whether the source expects that it
can achieve compliance by the specified compliance date.
2.5.5.4 Precompliance Report
The Precompliance Report would be required for affected
sources requesting an extension for compliance, or
requesting approval to use alternative monitoring
parameters, alternative continuous monitoring and
recordkeeping, or alternative controls.
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2.5.5.5 Notification of Compliance Status
The Notification of Compliance Status would be required
to be submitted within 150 days after the source's
compliance date. It shall contain the information for
emission points that need to comply with the rule, to
demonstrate that compliance has been achieved. Such
information includes, but is not limited to, the results of
any performance test for continuous and/or batch process
vents, ECO, or wastewater emission points; one complete test
report for each test method used for a particular kind of
emission point; design analyses for storage vessels and
wastewater emission points; monitored parameter levels for
each emission point and supporting data for the designated
level; and values of all parameters used to calculate
emissions credits and debits for emissions averaging. The
Notification of Compliance Status required by subpart H for
equipment leaks must be submitted within 90 days after the
compliance date.
2.5.5.6 Periodic Reports
Generally, Periodic Reports would be submitted
semiannually. However, if monitoring results show that the
parameter values for an emission point are above the maximum
or below the minimum established levels for more than one
percent of the operating time in a reporting period, or the
monitoring system is out of service for more than five
percent of the time, the regulatory authority may request
that the owner or operator submit quarterly reports for that
emission point. After one year, semiannual reporting can be
resumed, unless the regulatory authority requests
continuation of quarterly reports.
All Periodic Reports would include information required
to be reported under the recordkeeping and reporting
provisions for each emission point. For continuously
monitored parameters, the Periodic Report must report when
"excursions" occur. Table 4 shows what constitutes an
excursion.
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TABLE 4. SUMMARY OF EXCURSIONS
Emission
source type
Type of
excursion
Description of excursion
Continuous
Process Vents.
Daily average
exceedance.
When the daily average of a monitored
parameter is above the maximum, or below
the minimum, established level
Insufficient
monitoring data.
Insufficient monitoring data is when an
owner or operator fails to obtain a valid
hour of data for at least 75 percent of the
operating hours during an operating day.
Four 15-minute parameter measurements must
be obtained to constitute a valid hour of
data.
Batch Process
Vents.
Batch cycle
daily average
exceedance for
control
techniques other
than ECO.
When the batch cycle daily average of a
monitored parameter is above the maximum,
or below the minimum, established level.
Batch cycle
daily average
exceedance for
ECO.
When the batch cycle's value of a monitored
parameter is above the maximum, or below
the minimum, established level.
Insufficient
monitoring data.
Insufficient monitoring data is when an
owner or operator fails to obtain valid
parameter measurements for at least 75
percent of the 15-minute periods during an
operating day.
Periodic Reports would also include results of any
performance tests conducted during the reporting period and
instances when required inspections revealed problems.
Additional information on the source that is required to be
reported under its operating permit or Implementation Plan
would also be described in Periodic Reports.
Periodic Reports for subpart H must be submitted every
six months and must contain summary information on the LDAR
program changes to the process unit, changes in monitoring
frequency or monitoring alternatives, and/or initiation of a
QIP.
2.5.5.7 Other Reports
Other reports required under the proposed rule include
process changes that change the compliance status of process
vents, requests for extensions of the allowable repair
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period, and notifications of inspections for storage vessels
and wastewater.
2.5.5.8 Operating Permit Application
An owner or operator who submits an operating permit
application instead of a Precompliance Report shall submit
the information specified in the Precompliance Report, as
applicable, with the operating permit application.
3.0 RATIONALE FOR THE SELECTION OF POLLUTANT AND SOURCE
CATEGORY FOR CONTROL
The source category selected for the development of
this proposed rule was listed in the source category list
published on July 16, 1992 (57 FR 31576). The way in which
source categories or subcategories are defined is important,
because it dictates the basis upon which the MACT floor is
determined. The definition of the source category or
subcategory describes the "pool" of facilities that can be
used to define the MACT floor. This means that the MACT
floor must be determined on the same basis upon which the
source category is defined.
As discussed in section 2.1 of this document, the
polyether polyols production source category was separated
into two subcategories due to the process. These
subcategories are polyether polyols made with EO or PO
(epoxides), and polyether polyols made with THF.
Information gathered during the development of this proposed
rule indicated that facilities in both of these
subcategories are major sources, or are located at major
source plant sites.
The Agency obtained data from facilities that make
polyether products by polymerizing a compound having
multiple reactive hydrogen atoms, resulting in the formation
of a "polyol," and products made by polymerizing a compound
with a single reactive hydrogen, which forms a "mono-ol."
The Agency then investigated the distinctions between the
production units and the emissions controls for products
from these two groups. The Agency found no fundamental
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difference between the processes, the chemistry, the
emissions, or the types of control equipment. Further, many
producers use the same process equipment to produce polyols
and mono-ols, yet they generically refer to both types of
products as "polyols." Therefore, for the purposes of this
regulation, the Agency intends the term "polyether polyols"
to represent both polyether polyols and polyether mono-ols.
In defining the affected source for the regulation, the
EPA considered two options. One option was to define an
affected source as all the PMPUs at the same plant site.
The second option was to define the affected source as each
individual PMPU. The latter definition of an affected
source was chosen because multiple reactor trains, or
multiple PMPUs, are typically vented to the same header then
to the same control device. Also, different reactor trains
often use the same wastewater treatment system or storage
vessel (s) . With this broad affected source definition, the
applicability requirements would be the same if two separate
facilities delineate their reactor trains as separate PMPUs
or deem them to be part of one large PMPU.
4.0 RATIONALE FOR THE SELECTION OF THE EMISSION POINTS TO
BE COVERED BY THE PROPOSED STANDARDS
Emissions from the production of polyether polyols were
identified as occurring from storage vessels, process vents,
equipment leaks, and wastewater operations. The proposed
regulation includes standards for all of these emission
source types.
Epoxides, the primary HAP reactants, are much more
reactive than any other HAP used in the process and
typically have more stringent controls due to the explosive
nature of EO. Epoxide emissions are typically controlled by
scrubbers. The scrubbers control efficiency varies
depending on the solute's solubility in the scrubbing liquid
and its volatility. Therefore, a given scrubber operating
at the same conditions for EO control will get a different
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control efficiency for PO and yet another control efficiency
for another HAP.
Some facilities also remove the catalyst used in the
reaction, while others do not, depending on customer
specifications for purity of the product. The catalyst is
typically a basic compound that is usually neutralized with
an acid. Sometimes, this neutralization is the only
additional processing required. For those products that
require further processing, the salt that is formed from the
acid neutralization step is removed. Catalyst extraction
can be conducted by mechanically separating the catalyst
salt from the product(i.e., using filters or presses), or by
solvent extraction. Catalyst extraction using solvents
requires additional unit operations which may or may not be
physically attached to the processing units. The solvent
used could be a HAP, either hexane or toluene. Assuming a
scrubber is used to control process vent emissions, the
emissions from the HAP solvent are not controlled to the
same level as the epoxide emissions. Further, solvent HAP
emissions are sometimes controlled with a different control
device than that used for the epoxides, and are sometimes
uncontrolled.
In addition to the epoxide emissions and the HAP
emissions from catalyst extraction, there are also HAP
emissions from "incidental" HAP that are used as initiators
and solvents in the reaction. The quantities of HAP used in
this fashion are small, and the emissions are generally
vented to the same control device as the epoxide emissions.
As stated above, for a given scrubber, the control
efficiency for a nonepoxide HAP will usually be less than
the control efficiency for an epoxide. Further, if an
extended cookout is used as the control option, then there
could be minimal, if any, emission reduction for the
emissions of nonepoxide HAP.
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5.0 RATIONALE FOR THE SELECTION OF REGULATORY ALTERNATIVES
FOR EXISTING SOURCES
The approach for evaluating the MACT floors and
determining regulatory alternatives is discussed in detail
in the SID and is summarized in this section. This section
summarizes the MACT floors and regulatory alternatives more
stringent than the MACT floors considered by the EPA, and
the rationale for the selection of the level of the proposed
standards for new and existing sources.
5.1 The Maximum Achievable Control Technology Floor for
Existing and New Sources
The MACT floor level of control was identified for each
emission source grouping for both polyether polyols
subcategories (i.e., polyether polyols made with epoxides
and polyether polyols made with THF).
The EPA first considered a direct approach of comparing
the control technologies from the different sources to
determine the MACT floors. However, problems arose with
this approach due to the variations in control options and
the inability to quantify and numerically calculate average
performance levels for the best performing 12 percent of the
facilities. Therefore, the EPA studied methods to simplify
the MACT floor analysis, and decided to use the HON (40 CFR
63, subparts F, G, and H), in the MACT floor analysis as the
primary approach.
5.1.1 The Maximum Achievable Control Technology Floor
Analyses Approach for Storage Vessels, Equipment Leaks
and Wastewater
There are many similarities between the equipment,
emissions, and control techniques associated with the
polyether polyols industry and the synthetic organic
chemical manufacturing industry (SOCMI), which is regulated
by the HON. The HAP reactants and solvents used in the
polyols industry are all SOCMI chemicals, and many polyols
processes are co-located with SOCMI processes.
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The HON contains emission limitations for five emission
source types, and three of these emission limitations were
directly applied in the polyether polyols regulatory effort:
storage vessels, wastewater, and equipment leaks. For each
emission source type, applicability is based on the
"generic" characteristics of the emission point, such as HAP
emissions, HAP concentration, flow rate, size of the
equipment, etc. Thus, these applicability determinations
could easily be applied to polyether polyols production
sources.
A HON-based approach was practical, because the HON
provides "ready-made" alternatives. That is, the HON
analysis takes into account equipment type, equipment size,
equipment contents, stream characteristics, and other
important aspects of the emission source that should be
considered in the floor determination.
Because of the similarities between the SOCMI and
polyether polyols industries, the EPA concluded that the HON
requirements for storage vessels, wastewater, and equipment
leaks were appropriate to use in defining the MACT floor for
the polyether polyols production industry. As noted above,
the intent of this approach is to determine how controls at
existing polyols facilities compare to the level of control
that would be required by the HON for all emission types
except process vent emissions.
The HON-based type of analysis does not provide
specific numeric values for the MACT floor. Rather, the
conclusion of each floor analysis using this HON-based
approach is whether the MACT floor is less stringent than,
more stringent than, or equal to, the HON-level of control.
For each facility in each subcategory, the existing controls
were identified for each emission point. The existing level
of control was then compared to the level of control that
would be required by the HON, and the emission point was
characterized as being controlled at a level less stringent
than the HON requirements (less than HON), a level
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equivalent to the HON requirements (equal to HON), or a
level more stringent than the HON requirements (greater than
HON) .
After each emission point at each facility was
characterized, all emission points of a given emission
source type were grouped together and a facility-wide
determination was made for each emission source type. For
instance, if a storage vessel was controlled at a level less
stringent than the HON, and no other storage vessel was
controlled at a level more stringent than the HON, the
facility was classified as "less than HON" for storage
vessels. If all controls at the facility were equivalent to
the HON levels, the facility was classified as "equal to
HON." If one or more points was controlled at a level more
stringent than the HON, and no point of the same type was
controlled at a level less stringent than the HON at that
facility, the facility was classified as "greater than HON."
It is important to note, however, that if an emission
point was uncontrolled, and the HON would not require
control for that point, the level of control is equivalent
to the HON level of control. Therefore, the floor for a
subcategory could be the HON, when in fact all emission
points of that particular emission source type were
uncontrolled.
If a facility reported different levels of control (in
comparison to the HON) within one emission source type, an
additional analysis was necessary to classify the facility.
In these situations, the existing emission level was
compared to the emission level that would be required if HON
controls were applied. If the existing emissions were less
than the HON-level emissions, the facility was classified
"greater than HON," but if the HON-level emissions were
lower than the existing emissions, the facility was
classified "less than HON."
The floor for each emission source type was defined for
storage, wastewater and equipment leaks for both
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subcategories as less than, equal to, or greater than, the
HON level of control. The HON-based approach used for new
sources was similar to the existing source approach. The
level of control for each emission point was compared with
the level that would be required by the HON existing source
requirements.
5.1.2 The Maximum Achievable Control Technology Floor
Analyses Approach for Process Vents
For process vents a different approach from the HON-
approach was utilized, because several facilities reported
pollution prevention techniques (i.e., extended cookout) for
which the EPA wanted to give credit. During the presumptive
MACT (PMACT) process, the EPA first proposed the use of
emission factors to establish the MACT floor. Industry
representatives insisted that emission factors were
influenced by individual product properties. They noted
that the reactivity of PO is an order of magnitude slower
than EO; therefore, there would be twice as many
uncontrolled PO emissions as EO emissions from the same PMPU
if PO was the last reactant added versus if EO was the last
reactant added. They reported that the emission factor
approach favored facilities that predominately use EO over
similarly equipped facilities that use PO. Industry
representatives commented that they did not like this
emission factor approach without subcategorizing all the
possible "classes" of products. They stated that this
classification was necessary because the control efficiency
for EO is better than that for PO for a given recovery
device, and the approach of one emission factor for the
source category would not be fair to facilities that use
more PO than EO in their product mix. Industry
representatives requested that the EPA utilize a percent
emission reduction approach to calculate the MACT floor
instead of the emission factor approach, stating that they
would cooperate with the EPA in developing an emission
reduction calculation for the ECO. Therefore, this approach
30
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was abandoned in favor of quantifying a percent emission
reduction.
The percent emission reduction approach calculated
aggregated emission reduction from all the process vent
emissions within a PMPU, for every facility in the database
The following calculation was used:
= E(£EU -
x 100%
where:
R = Emission reduction, percentage;
Eu = Uncontrolled epoxide process vent emissions,
pounds per year, (Ib/yr); and
Ec = Controlled epoxide process vent emissions, Ib/yr.
5.1.3 Maximum Achievable Control Technology Floor Analysis
Results for Polyether Polyols made with Epoxides
Tables 5 and 6 present the MACT floors for existing and
new sources producing polyether polyols with epoxides. The
sections that follow describe the rationale for these
conclusions.
Table 5. MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY FLOORS FOR
EXISTING SOURCES OF POLYETHER POLYOLS WITH EPOXIDES
Storage
HON
Process Vent
Oxides
98 percent
Nonepoxides
from making
or modifying
the product
0 percent
Nonepoxide
from catalyst
extraction
90 percent
Equipment
Leaks
HON
Wastewater
No control
31
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Table 6. MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY FLOORS FOR
NEW SOURCES OF POLYETHER POLYOLS WITH EPOXIDES
Storage
HON
Process Vent
Oxides
99.9
percent
Nonepoxides
from making
or modifying
the product
39 percent
Nonepoxide
from catalyst
extraction
98 percent
Equipment
Leaks
HON
Wastewater
No control
5.1.3.1 Storage Vessels
The MACT floor level of control for storage vessels at
existing sources that make polyether polyols with oxides was
determined to be the HON level of control and applicability.
The rationale for this determination follows. The majority
of the vessels were pressurized (which are exempt from the
HON requirements), with only four facilities reporting
vessels that were HON Group 1 storage vessels (see Table 3
for the applicability cutoffs). It was determined that
these four facilities have storage vessels that would
require control under the HON. Three of these four
facilities with HON Group 1 storage vessels have HON
reference control technologies on their HON Group 1 storage
vessels; therefore, the MACT floor level of control for
storage vessels at existing sources was determined to be
equal to the level of control in the HON. No facility had
controls more stringent than the HON level of control for
their Group 1 vessels; therefore, the MACT floor level of
control for storage vessels at new sources is the HON
existing source storage vessel level of control.
5.1.3.2 Equipment Leaks
The database of 13 facilities reporting equipment leak
information indicated that nine out of 13 facilities have
LDAR programs in place. Of the nine LDAR programs in place,
six were reported to be equal to the level of stringency
required by the HON (i.e., in terms of monitoring frequency
32
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and leak definition). No facility reported an equipment
leak emission control program more stringent than the HON
existing source level of control. Therefore, the MACT floor
level of control for equipment leaks for new and existing
sources was determined to be the level of control required
by the HON (40 CFR 63, subpart H).
5.1.3.3 Process Vents
Three sets of MACT floor levels of control were
established for process vent emissions: one for epoxides
(EO and PO) emissions; a second for nonepoxide HAP emissions
from catalyst extraction; and a third for emissions of
nonepoxide HAP used to make or modify the product. For the
epoxide subcategory, the MACT floor levels were established
by determining the average emission control for the best
performing 12 percent of the facilities with respect to the
emission point. Since it was assumed that the EPA's
database of 28 facilities making polyols with epoxides is
representative of the industry as a whole, the best
performing 12 percent of the database was equated with the
best performing 3.36 facilities. In calculating the
"average" emission control, the median approach was used to
measure central tendency where there was a wide range of
values within the best performing facilities. For new
sources, the MACT floor levels were established by
determining the emission control for the best controlled
facility for that emission point of the subcategory.
5.1.3.3.1 Epoxide Emissions
The MACT floor for epoxide emissions from process vents
at existing facilities that produce polyether polyols with
epoxides was calculated as the median of the top twelve
percent of the database. The MACT floor was calculated to
be a 98.1 percent control efficiency, and was rounded to 98
percent since the standard is technology based and it is
believed that facilities would not use a different control
technology to meet a standard that is a tenth of a percent
more stringent.
33
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The MACT floor level of control for epoxide emissions
from process vents at new sources was determined to be a
control efficiency of 99.9 percent. This new source MACT
floor was based on a facility that reported a control
efficiency of 99.9 percent.
5.1.3.3.2 Nonepoxide HAP Emissions from Catalyst
Extraction
For nonepoxide HAP emissions from catalyst extraction,
the MACT floor was determined as the median of the data in
the database, which was 90 weight percent aggregated
emission reduction for existing sources. The MACT floor
level of control for new sources was determined to be 98
weight percent aggregated emission reduction.
5.1.3.3.3 Nonepoxide HAP From Making or Modifying the
Product
For nonepoxide HAP process vent emissions from making
or modifying the product at existing sources, the MACT floor
level of control was calculated using the median of the top
twelve percent. The existing source MACT floor level of
control for nonepoxide HAP emissions from making or
modifying the product was determined to be no control. The
new source MACT floor level of control for nonepoxide HAP
process vent emissions was determined to be 39.0 percent
control efficiency.
5.1.3.4 Wastewater
The MACT floor level of control for wastewater for new
and existing sources was identified to be less than the HON
level of control. In fact, the level of control is no
control. The database indicated that only two facilities in
the database reported Group 1 wastewater streams that
require controls according to the HON, and neither facility
controlled air emissions from these wastewater streams.
Further, of the Group 2 wastewater streams that were
reported, none had air emission controls.
34
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5.1.4 Maximum Achievable Control Technology Fl
Polyether Polyols Made with Tetrahydrofuran
Only one of the two facilities in the database for the
THF subcategory use and emit organic HAP. Therefore, the
MACT floor analysis was based on the one facility that uses
and emits HAP. This one source also sets the level of
control for the new source MACT floor for THF
polymerization.
Table 7 summarizes the MACT floor determination. The
following sections present a summary of the analysis for
this determination.
Table 7. MACT FLOOR FOR EXISTING AND NEW SOURCES OF
POLYETHER POLYOLS MADE WITH TETRAHYDROFURAN
Storage
No control
Process Vents
No control
Equipment
Leak
No
control
Wastewater
No control
5.1.4.1 Storage Vessels
The MACT floor level of control for new and existing
sources was identified as the HON level of control. Only
one of the THF facilities had a storage vessel for HAP.
This storage vessel was a Group 2 vessel that does not
require controls (see Table 3 for the Group I/Group 2
determination) and did not have a control.
5.1.4.2 Process Vents
The facility that uses organic HAP in its process does
not control the process vent emissions of the organic HAP.
The second facility in the database emits hydrogen fluoride
and has minimal controls (approximately 20 percent emission
reduction) on these emissions. Therefore, the MACT floor
level of control for process vents from polyether polyols
produced using THF at existing sources was identified to be
no control.
35
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5.1.4.3 Equipment Leaks
No control of emissions from equipment leaks was
reported at the facility that polymerizes THF. Therefore,
the MACT floor for equipment leaks at existing and new
facilities was determined to be less than the HON level of
control. More specifically, the MACT floor level of control
is no control.
5.1.4.4 Wastewater
The MACT floor for wastewater for existing and new
facilities that produce polyols by polymerization of THF was
determined to be equal to the HON level of control. No
Group 1 wastewater streams were reported and no controls
were reported for the Group 2 wastewater streams reported.
More specifically, the MACT floor level of control is no
control.
5.2 The Rationale for the More Stringent Regulatory
Alternative Considered for Existing Sources
Only one regulatory alternative more stringent than the
MACT floor level of control was developed and considered for
each subcategory. Table 8 presents the MACT floor and the
regulatory alternative for existing sources
or each subcategory. The rationale for the level of this
alternative is discussed below.
5.2.1 Polyether Polyols made with Epoxides Subcategory
The MACT floor level of control for storage vessels and
equipment leaks was equal to the HON level of control.
Therefore, the regulatory alternative included the HON level
of control for these emission types.
The MACT floor level of control was determined to be
less stringent than the HON level of control (i.e., no
control) for wastewater emissions. The HON level of control
was considered for the regulatory alternative. The HON
level of control was considered for wastewater because it
had received extensive evaluation during the development of
the HON, at which time the EPA concluded that the cost and
other impacts of the HON-level of control were reasonable.
36
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Therefore, the regulatory alternative included the HON level
of control for wastewater.
During the development of the HON, alternatives more
stringent than the promulgated levels were considered and
rejected by the EPA. Therefore, it was unnecessary to
consider controls more stringent than the HON levels, since
this industry closely mirrors the SOCMI and the EPA had
previously considered them unacceptable for the HON. For
the process vent regulatory alternatives, an emission
reduction format was chosen and applied to the three groups
of HAP process vent emissions: epoxide emissions;
nonepoxide HAP emissions from the making or modification of
the product, and; nonepoxide HAP emissions from catalyst
extraction. The MACT floor level of control for epoxide
process vent emissions was considered sufficiently stringent
since it mirrored the highest level of control in the batch
ACT (without performing a cost effectiveness analysis to
determine applicability). Therefore, no levels of control
more stringent than the floor were evaluated.
The MACT floor level of control for nonepoxide HAP
emissions from making or altering the product was determined
to be an aggregated control efficiency of 0 percent. The
EPA determined that the applicability criteria from either
the HON or the Batch ACT could be applied for process vents
from continuous or batch unit operations, respectively. The
Group determination was deemed appropriate because the
equation in the HON for determining Group I/Group 2
applicability, the total resource effectiveness index (TRE)
has an inherent cost effectiveness value in it. After
determining the Group status, the control requirement from
the HON, a 98 percent control efficiency, was used in this
regulatory alternative as well. If the process vent was
from a batch unit operation the group determination was used
based on equations first developed in the "Control of
Volatile Organic Compound Emissions From Batch Processes"
37
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(EPA-453/R-93-017) (Batch ACT), and used in the Polymer and
Resins I NESHAP. This alternative control technique (ACT)
document provides guidance to State and local air pollution
regulatory agencies on the development of regulations for
air emissions from batch processes. Due to the similarities
between the processes studied in the Batch ACT and the
polyols production batch unit operations, and the general
nature of the applicability criteria, the EPA concluded that
these criteria were appropriate to use in defining the
alternatives for process vents from batch unit operations in
the polyols production industry. The 90-percent control
level from the Batch ACT was selected because the facilities
that did report controls on these streams, reported
condensers, and 90 percent was the lowest control efficiency
achieved. Further, the estimated cost-effectiveness for
this level was comparable to the cost-effectiveness of the
HON continuous vent provisions. Based on these previous
analyses, the EPA determined that it was acceptable to
consider the single regulatory alternative beyond the MACT
floor level.
5.2.2 Polyether Polyols made with Tetrahydrofuran
The MACT floor level of control for all the emission
types was determined to be less stringent than the HON level
of control. For these same reasons as presented for the
other subcategory, the regulatory alternative included the
HON level of control for storage vessels, equipment leaks,
and wastewater. For the process vent emissions, similar to
the other subcategory, the HON or Batch ACT Group
determination was included in the regulatory alternative.
5.3 The Rationale for More Stringent the Regulatory
Alternatives Considered for New Sources
For new sources, only one regulatory alternatives more
stringent than the MACT floor was considered. Table 9
presents the MACT floor and the regulatory alternative for
new sources. The rationale for the level of this
alternative is discussed below.
39
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5.3.1 Polyether Polyols made with Epoxides Subcategory
For storage and equipment leaks, the MACT floor level
of control for these emission types was equal to the HON
level of control for existing sources. The EPA determined
it was not necessary to evaluate the HON level of control
for new sources, because no facilities in the database
reported this level of control. Therefore, the regulatory
alternative consisted of the MACT floor level of control for
these two emission types.
For wastewater, the MACT floor level of control was
less stringent than the HON level of control. Similar to
the explanation for existing sources, the EPA considered
this option to be appropriate because when the EPA developed
the HON, the cost effectiveness of the control options were
considered in the group determination. The new source HON
level of control was not considered because none of the
facilities in the database reported any controls for
wastewater emissions. Therefore, the regulatory alternative
included the existing source HON level of control for
wastewater.
For epoxide emissions from process vents, the MACT
floor level of control was 99.9 percent control efficiency.
The EPA did not evaluate options more stringent than this
level of control, because this control efficiency is already
more stringent than that required in the HON. Also, for
nonepoxide HAP process vent emissions from catalyst
extraction, the MACT floor level of control was determined
to be 98 percent aggregated emission reduction. This level
of control was the highest in the database, and was
determined to be adequate for this emission type.
For nonepoxide emissions from making or altering the
product, the MACT floor level of control was less stringent
than the HON level of control. Because the levels of
control for the HON and the Batch ACT are already above the
level of control of the floor for this emission type, and
because no one source in the database demonstrated control
40
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levels more stringent than the existing source HON or Batch
ACT levels of control, no new source levels of control from
the HON/Batch ACT were considered.
5.3.2 Polyether Polyols made with THF Subcategory
For the subcategory of polyether polyols made with THF,
as stated above, there is only one source in the database.
Therefore, the MACT floor for existing sources and new
sources is the same. The rationale to consider the more
stringent control levels than the MACT floor levels of
control were discussed previously in the existing source
section. Also discussed previously, the EPA did not
determine any need to examine new source levels of control
from the HON for the new source regulatory alternative.
5.4 RATIONALE FOR THE SELECTION OF CONTROL LEVELS OF THE
PROPOSED STANDARDS
The MACT floor level of control for each emission type
was presented previously in this document. The regulatory
alternative represents a level of control more stringent
than the MACT floor. Table 10 shows the cost-effectiveness
values for all options more stringent than the MACT floor,
as well as the overall cost effectiveness for the regulatory
alternative for each subcategory.
The regulatory alternative represents a level of
control more stringent than the MACT floor. As shown in the
Table 10, the highest cost-effectiveness for an individual
emission source type for either subcategory is $3,500 per
megagram. The overall regulatory alternative cost-
effectiveness values for the regulatory alternative for
polyether polyols made with epoxides is $3,500 per megagram
and $3,400 per megagram for polyether polyols made with THF.
The incremental cost-effectiveness values for going to this
regulatory alternative from the MACT floor is equal to the
cost effectiveness of that option. Considering these cost
impacts, as well as non-air environmental and energy
impacts, the EPA judged that the level of control for this
regulatory alternative was reasonable. Therefore, the EPA
42
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selected the regulatory alternative as the level of the
proposed standards. The EPA selected the regulatory
alternative more stringent than the floor for new sources.
New sources were not projected for the next five years;
therefore, no impact analysis or cost effectiveness value
calculations were conducted for new sources.
6.0 RATIONALE FOR THE SELECTION OF THE FORMATS OF THE
PROPOSED STANDARDS
As discussed in the introduction to this chapter, the
decision to use the HON in the determination of most of the
MACT floor and regulatory alternative levels of control
predetermined that the format of the proposed rule would
resemble the HON. Therefore, the proposed standards would
adopt the formats found in the HON for storage vessels,
nonepoxide process vents from continuous unit operations
that make or modify the product, wastewater, and equipment
leaks. Similarly, the format of the applicability
provisions of the batch process vent provisions would be
adopted from the Polymer and Resins I NESHAP. The Federal
Register notice for the proposed HON (57 FR 62608, December
31, 1992) provides the rationale for the selection of the
specific formats used in the HON. The Basis and Purpose
Document from the Polymer and Resins I NESHAP refers to the
Batch Processes ACT document where the rationale for the
selection of the recommended formats for batch process vents
are discussed.
In addition to adopting formats of existing standards,
the proposed rule also contains standards for controlling
epoxide emissions from process operations and nonepoxide HAP
in catalyst extraction. The format for both of these
proposed process vent standards is a minimum aggregated
control efficiency for the total of all applicable emissions
within a PMPU. The following sections provide, on an
emission source type basis, more detailed discussions of the
rationale for the selection of the formats of the proposed
standards.
43
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6.1 Storage Vessels
For storage vessels the format of these proposed
standards is dependent on the method selected to comply with
the standards. If tank improvements (e.g., internal or
external floating roofs with proper seals and fittings) are
selected, the format is a combination of design, equipment,
work practice, and operational standards. If a closed vent
system and control device are selected, the format is a
combination of design and equipment standards.
6.2 Process Vents
6.2.1 Process Vents in the Polyether Polyols with
Tetrahydrofuran Subcategory
For process vents in the subcategory that uses THF, the
format of the proposed standard is adopted from the HON. As
with storage vessels, the format is also dependent on the
method selected to comply with the standards. If a flare is
selected, the format is a combination of equipment and
operating specifications. If a control device other than a
flare is used, the formats are a percent reduction and an
outlet concentration.
6.2.2 Epoxide Process Vent Emissions in the Polyether
Polyol with Epoxide Subcategory
For epoxide emissions from process vents that make
polyether polyols using epoxides, the format of these
proposed standards is a percent reduction from the aggregate
of all process vents streams within the PMPU. A PMPU basis
was chosen for all the process vent standards because the
vents and venting episodes from one or more reactor trains
are interrelated in that they are commonly put into the same
header and fed to a single control device.
6.2.3 Nonepoxide Organic HAP Process Vent Emissions
from Making or Modifying the Product in the Polyether
Polyol with Epoxide Subcategory
Process vent emissions from the use of nonepoxide
organic HAP to make or modify the polyether polyol product
45
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can be from either a batch unit operation or a continuous
unit operation.
For process vents from continuous unit operations, the
format of the proposed standards is adopted from the HON.
The format is also dependent on the method selected to
comply with the standards. If a flare is selected, the
format is a combination of equipment and operating
specifications. If a control device other than a flare is
used, the formats are a percent reduction and an outlet
concentration.
HAP emissions from a Group 1 batch process vent must
reduce HAP emissions by 90-percent over the batch cycle.
During a production cycle in a batch unit operation, there
are often emission episodes resulting from several different
steps of the batch process. The vent streams from each of
these emission episodes can differ significantly in flow
rate, HAP concentration, and other characteristics important
in the ability to apply controls. The 90-percent control
requirement is on a batch cycle basis, rather than a
continuous basis, to allow owners and operators the
flexibility to control emission episodes to varying levels,
as long as the 90-percent reduction for all emission
episodes in the cycle is accomplished.
6.2.4 Nonepoxide Organic HAP from Catalyst Extraction
in the Polyether Polyol with Epoxide Subcategory
The process vents with organic HAP resulting from the
use of organic HAP in catalyst extraction are continuous
vents that have adopted a 90 percent aggregate emission
reduction format for the subcategory that uses epoxides.
This was chosen to allow for the most flexibility with
respect to control options.
6.3 Equipment Leaks
For equipment leaks from both subcategories, these
proposed standards incorporate several formats: equipment,
design, lowest allowable performance levels (e.g., maximum
allowable percent leaking valves), work practices, and
46
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operational practices. Different formats are necessary for
different types of equipment, available control techniques,
and applicability of the measurement method. In addition, a
work practice standard is adopted for equipment leaks
resulting in the emission of HAP from cooling towers at all
facilities producing polyether polyols. This standard
requires the leak detection and repair of leaks of HAP into
cooling tower water.
6.4 Wastewater Operations
For wastewater streams requiring control from both
subcategories, these proposed standards incorporate several
formats: equipment, operational, work practice, and
emission standards. The particular format selected depends
on which portion of the wastewater stream is involved. For
transport and handling equipment, the selected format is a
combination of equipment standards and work practices. For
the reduction of HAP from the wastewater stream itself,
several alternative formats are incorporated, including five
alternative numerical emission limit formats (overall
percent reduction for total organic HAP, individual HAP
percent reduction, effluent concentration limit for total
organic HAP, individual organic HAP effluent concentration
limits, and mass removal for HAP) and equipment design and
operation standards for a steam stripper. For vapor
recovery and destruction devices other than flares, the
format is a weight percent reduction. For flares, the
format is a combination of equipment and operating
specifications.
7.0 RATIONALE FOR THE SELECTION OF COMPLIANCE AND
PERFORMANCE TEST PROVISIONS
For the most part, the control devices and level of
control required by the proposed rule are modeled after
those in subparts F, G, H and U. Further, the control
devices likely to be used in complying with the proposed
requirements for batch process vents were already considered
as part of subparts G and U. As a result, the EPA has
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determined that there is no need to change performance
testing provisions or the parameters selected for
monitoring. Since the rationale for the selected provisions
has been presented in detail in the preambles to the
proposed subpart and promulgated subparts F, G, H, and U it
is not repeated here in the same depth. The paragraphs
below briefly discuss the rationale for the selected
provisions for each emission source type. Later in this
section, the rationale for the use of parameter monitoring
and for the overall compliance certification provisions are
presented.
7.1 Storage Vessels
The proposed storage vessel provisions require control
by tank improvements or a closed vent system and control
device; however, the choice of control technologies is
limited depending on the material stored. For vessels
storing liquids with vapor pressures less than 76.6 kPa,
either control option may be selected. However, for vessels
storing liquids with vapor pressures greater than or equal
to 76.6 kPa, tank improvements do not achieve the expected
level of emission reductions. As a result, Group 1 storage
vessels containing liquids with a maximum true vapor
pressure of organic HAP greater than or equal to 76.6 kPa
must be controlled with a closed vent system and control
device.
7.2 Process Vents
7.2.1 Group Determination for Process Vents from.
Continuous Unit Operations
Except as discussed in the next paragraph, the proposed
rule requires each owner or operator to determine for the
combination of process vents from a continuous unit
operation whether the combination of the vents is a Group 1
or Group 2. There are three group determination procedures:
(1) process vent flow rate measurement, (2) process vent HAP
concentration measurement, and (3) TRE index value
determination. A detailed discussion of the rationale for
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these three procedures is found on pages 62636-62637 of
Federal Register Vol. 57, No. 252, December 31, 1992.
Alternatively, an owner or operator may choose to
comply directly with the requirement to reduce organic HAP
emissions by 98 weight percent or to an outlet concentration
of 20 ppmv.
7.2.2 Group Determination for Process Vents from Batch Unit
Operations
As for process vents from continuous unit operations,
some process vents from batch unit operations are more cost
effective to control than others. Therefore, cost
effectiveness is related to the procedures that are being
proposed for the group determination for process vents from
batch unit operations. These procedures are taken from the
Batch ACT document. The Batch ACT describes applicability
criteria (i.e., annual emissions and annual average
flowrate) for distinguishing between process vents from
batch unit operations that are cost effective to control and
those that are not. The rationale for these applicability
criteria and procedures is presented in depth in the Batch
ACT document.
The proposed rule allows the determination of annual
HAP emissions using a series of equations that are from the
Batch ACT and included in the rule. As an option to using
these equation, owners and operators can use testing to
determine emissions. The proposed rule requires that
testing be conducted to determine flow rates for each batch
emission episode, which are then used to calculate an annual
average flow rate.
For the same reasons the proposed rule requires a
performance test and continuous monitoring of a control
device for a process vent from a continuous unit operation,
performance tests and continuous monitoring are required for
the control or recovery devices used by a source to comply
with the process vent from batch unit operations control
requirement. Also, the monitoring parameters selected for
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recovery devices were presented and discussed as part of the
process vent from continuous unit operations provisions and
in the preamble to the proposed subpart G. Compliance for
process vents from batch unit operations is on a batch-cycle
basis, rather than on a continuous basis.
7.2.3 Performance test
Initial performance tests are required for all control
devices other than flares and certain boilers and process
heaters. Specifically, testing would be required for:
(1) incinerators, (2) some boilers and process heaters
smaller than 44 MW (150 million Btu/hr), and (3) extended
cookout. Performance tests are being required because they
(1) ensure that a control device achieves the required
control level and (2) serve as the basis for establishing
operating parameter levels required for monitoring.
Because their percent reduction and outlet
concentration cannot feasibly be measured, flares are not
required to meet the requirements in Section 63.11 for
operating conditions.
7.2.4 Test methods
The proposed process vent provisions would require the
use of approved test methods to ensure consistent and
verifiable results for group determination procedures,
initial performance tests, and compliance demonstrations.
7.2.5 Monitoring
Control devices used to comply with the proposed rule
need to be maintained and operated properly if the required
level of control is to be achieved on a continuing basis.
Monitoring of the control device operating parameters can be
used to ensure that such proper operation and maintenance
are occurring.
The proposed standard lists the parameters that can be
monitored for the common types of combustion devices:
firebox temperature for thermal incinerators,- temperature
upstream and downstream of the catalyst bed for catalytic
incinerators; firebox temperature for boilers and process
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heaters; and presence of a flame at the pilot light for
flares. These parameters were selected because they are
good indicators of combustion device performance, and
instruments are readily available at a reasonable cost to
continuously monitor these parameters. The proposed rule
also allows the owner or operator to request to monitor
other parameters on a site-specific basis.
The proposed standard would require the owner or
operator to establish site-specific parameter levels through
the Notification of Compliance Status report and operating
permit. Site-specific parameter levels accommodate site-
specific differences in control design and process vent
stream characteristics.
For Group 2 process vents from continuous unit
operations that have TRE index values greater than 1.0 but
less than or equal to 4.0, monitoring of the final recovery
device would be required to ensure that it continues to be
operated as it was during the group determination test when
the initial TRE index value was calculated. Improper
recovery device operation and maintenance could lead to
increased organic HAP concentration, potentially reducing
the TRE index value below 1.0, and causing the vent to
become a Group 1 process vent. Continuous monitoring will
ensure continued good performance of recovery devices. The
TRE index value monitoring level of 4.0 is being proposed
because the variability of the process parameters
established during normal operating conditions are unlikely
to vary to the extent that a TRE value above 4.0 would be
reduced to a TRE level less than 1.0 and thus require
control.
The proposed rule specifies the parameters that can be
monitored for the two common types of recovery devices, and
present the parameters for carbon absorption in the event
that this recovery device is used: exit temperature of the
absorbing liquid and exit specific gravity for absorbers;
exit temperature for condensers; and 1) total regeneration
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stream mass flow during carbon bed regeneration cycle and 2)
temperature of the carbon bed after regeneration for carbon
adsorbers. These parameters were selected because they are
good indicators of recovery device performance, and
instruments are readily available at a reasonable cost to
continuously monitor these process parameters. The proposed
rule also allows the owner or operator to request to monitor
parameters on a site-specific basis. The owner or operator
would establish a site-specific level for the parameters
through the Notification of Compliance Status report and
operating permit.
7.3 Wastewater Operations
Two important parameters must be quantified initially
and whenever process changes are made to determine whether a
process wastewater stream is a Group 1 or Group 2 stream.
These parameters are the annual wastewater quantity for a
stream and the organic HAP concentration of HAP in the
stream. The organic HAP concentration can be quantified as
a flow-weighted annual average for total organic HAP or for
individually-speciated HAP. Several methods are allowed by
the proposed rule for determining both of these parameters.
Initial performance tests for control of Group 1
wastewater streams are not required by the proposed rule.
For treatment processes and control devices, facilities have
the choice of using either performance tests or engineering
calculations to demonstrate the compliance of those units
with the standards. Engineering calculations, supported by
the appropriate documentation, have been allowed to provide
a less costly alternative to that of actual testing.
A performance test is not specified for the design
steam stripper. Installation of the specified equipment,
along with monitoring to show attainment of the specified
operating parameter levels, demonstrates compliance with the
equipment design and operation provisions. Thus, a
performance test is not necessary.
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The proposed process wastewater provisions include
requirements for periodic monitoring and inspections to
ensure proper operation and maintenance of the control
system and continued compliance.
7.4 Equipment Leaks
The proposed rule retains the use of Method 21 to
detect leaks of organic compounds from equipment; however,
several modifications were made to the existing procedures.
These modifications consist of changes to the calibration
gases required, addition of procedures for response factor
correction, and addition of procedures for pressure testing
of batch processes. The bases for the changes to the
provisions are presented in the preamble to the proposed
subpart H.
In addition, periodic monitoring for leaks is required
to demonstrate compliance for heat exchange systems. The
frequency of periodic monitoring becomes less frequent as
data show that leaks are not present. This monitoring
system is proposed to minimize the burden on the source.
8.0 RATIONALE FOR THE SELECTION OF MONITORING REQUIREMENTS
The proposed rule requires monitoring of control and
recovery device operating parameters and reporting of
periods when parameter values are above maximum or below
minimum established levels. Section 114(a)(3) of the Act
and Section 70.6 (c) of the operating permit rule
(57 FR 32251) require the submission of "compliance
certifications" from sources subject to the operating permit
program. Section 114(a)(3) of the Act requires enhanced
monitoring and compliance certifications of all major
stationary sources. The annual compliance certifications
determine whether compliance has been continuous or
intermittent. Enhanced monitoring shall be capable of
detecting deviations from each applicable emission
limitation or standard with sufficient representativeness,
accuracy, precision, reliability, frequency, and timeliness
to determine if compliance is continuous during a reporting
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period. The monitoring in this regulation satisfies the
requirements of enhanced monitoring.
In light of these requirements, the EPA has considered
how sources subject to this rule would demonstrate
compliance. The EPA has concluded that operating parameter
monitoring can be used for this purpose.
For the proposed rule, the EPA is requiring sources to
establish site-specific parameter levels. Allowing site-
specific levels for monitored parameters accommodates site-
specific variation in emission point characteristics and
control device designs. The proposed procedure for
establishing operating parameter levels for process vents
from continuous and batch unit operations, complying using
add-on control, is based on performance tests.
For process vents from batch unit operations and
continuous unit operations complying using add-on controls,
the proposed rule requires the source to record daily
average values for continuously monitored parameters. The
daily average is the average of all of the 15-minute values
generated by the continuous recorder during the operating
day. If the daily average value is not in accordance with
the established level, it must be reported. The daily
averaging period was selected because the purpose of
monitoring data is to ensure proper operation and
maintenance of the control device. Because it often takes
from 12 to 24 hours to correct a problem, this averaging
period was considered to best reflect operation and
maintenance practices. This averaging period gives the
owner or operator a reasonable period of time to take
action. If a shorter averaging period (for example 3 hours)
was selected, sources would be likely to have multiple
excursions caused by the same operational problem, because
it would not be possible to correct problems in one 3-hour
reporting period.
In the proposed rule, as in subpart G, at least 75
percent of monitoring data is required to constitute a valid
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day's worth of data. Parameter monitoring problems not
addressed under the startup, shutdown, and malfunction plan
will not result in an excursion if at sufficient data are
available. For example, for process vents from continuous
unit operations, a source needs to have valid monitoring
data for at least 75 percent of the operating hours in a
given operating day to have a valid day's worth of
monitoring data. Excused excursions are not included in the
proposed rule because most continuous monitoring system
problems can be dealt with within the context of the
startup, shutdown, and malfunction plan required under
subpart A.
Consistent with the proposed parameter monitoring
requirements for process vents, the EPA is proposing that
failure to provide sufficient monitoring data for at least
75 percent of required batches is a violation of the
standard. However, the definition of insufficient
monitoring data for a process vent from a batch unit
operation required further EPA consideration. For process
vents from continuous unit operations, the period is an
hour, and an hour is considered to have sufficient
monitoring data only if four 15-minute parameter values are
recorded.
When ECO is used as a control technique, the owner or
operator is required to monitor one of the parameters
listed: time from the end of the epoxide feed; the epoxide
partial pressure in the reactor, or; the direct measurement
of epoxide concentration in the reactor liquid at the end of
the ECO. This data is required for every batch whose air
emissions are controlled by ECO.
9.0 SELECTION OF RECORDKEEPING AND REPORTING REQUIREMENTS
The general recordkeeping and reporting Requirements of
this subpart are very similar to those found in subpart G of
part 63. The proposed rule also relies on the provisions of
subpart A of part 63. A table included in the proposed rule
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designates which sections of subpart A apply to the proposed
rule.
Records of reported information and other information
necessary to document compliance with the regulation are
generally required to be kept for 5 years. A few records
pertaining to equipment design would be kept for the life of
the equipment.
As discussed in section 2.5.5, the proposed rule
requires sources to submit the following eight types of
reports:
1. Startup, shutdown, and malfunction plan,
2. Application for Approval of Construction or
Reconstruction,
3. Initial Notification,
4. Precompliance Report,
5. Notification of Compliance Status,
6. Periodic Reports,
7. other reports, and
8. Operating permit application.
The wording of the proposed rule requires all draft
reports to be submitted to the "Administrator". The term
Administrator means either the Administrator of the EPA, an
EPA regional office, a State agency, or other authority that
has been delegated the authority to implement this rule. In
most cases, reports will be sent to State agencies.
Addresses are provided in subpart A of part 63.
10.0 OPERATING PERMIT PROGRAM
Under Title V of the 1990 Amendments, all HAP-emitting
facilities subject to this rule will be required to obtain
an operating permit. Oftentimes, emission limits,
monitoring, and reporting and recordkeeping Requirements are
scattered among numerous provisions of State implementation
plans (SIP's) or Federal regulations. As discussed in the
proposed rule for the operating permit program published on
May 10, 1991 (58 FR 21712), this new permit program would
include in a single document all of the Requirements that
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pertain to a single source. Once a State's permit program
has been approved, each facility containing that source
within that State must apply for and obtain an operating
permit. If the State wherein the source is located does not
have an approved permitting program, the owner or operator
of a source must submit the application under the General
Provisions of 40 CFR part 63.
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U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, It. 60604-3590
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