August 29, 1996

MEMORANDUM 

SUBJECT: Clarification of Methodology for Calculating Potential 

to Emit (PTE) for Batch Chemical Production Operations 

FROM: John S. Seitz, Director 

Office of Air Quality Planning and Standards (MD-10) 

TO: See Addressees 

This guidance memorandum is to clarify the Environmental

Protection Agency’s (EPA) policy regarding the appropriate

methodology for determining PTE for batch chemical operations in

light of inherent physical limitations on such sources’ PTE

arising from the inability of a source to use a given operation

unit for the production of more than one product at a time.

Summary of Guidance

The guidance (Attachment 1) contains a discussion of the

batch chemical industry and the steps for determining a source’s

PTE. The EPA includes as part of the guidance a document

(Attachment 2) prepared by the Synthetic Organic Chemical

Manufacturers Association (SOCMA). The EPA approves the

methodology suggested by SOCMA, so long as the methodology

incorporates an appropriate list of products and raw materials. 

The guidance includes a discussion of how to use the SOCMA

methodology for determining major source applicability.

Distribution/Further Information

The Regional Offices should send this memorandum to States

within their jurisdiction. Questions concerning specific issues

and cases should be directed to the appropriate Regional Office. 

The Regional Office staff may contact Timothy Smith of the

Integrated Implementation Group at 919-541-4718. The document is

also available on the Technology Transfer Network Bullentin Board 
2

System (TTN BBS), under “Clean Air Act, Title V, Policy Guidance

Memos.” (Readers unfamiliar with this bulletin board may obtain

access by calling the TTN help line at 919-541-5384).

Attachment

Addressees:

Director, Office of Ecosystem Protection, Region I

Director, Air and Waste Management Division, Region II

Director, Air, Radiation and Toxics Division, Region III

Director, Air, Pesticides and Toxics Management 

Division, Region IV

Director, Air and Radiation Division, Region V

Director, Multimedia Planning and Permitting Division, Region VI

Director, Air, RCRA and TSCA Division, Region VII

Director, Office of Pollution Prevention, State and Tribal

Assistance, Region VIII

Director, Air and Toxics Division, Region IX

Director, Office of Air, Region X

cc: Bruce Buckheit, 2242A

Randy McDonald, MD-13

Adan Schwartz, 2344

Timothy Smith, MD-12

Air Branch Chief, Regions I-X

Regional Air Counsels, Regions I-X

OECA concurred: August 22, 1996
Attachment 1

CLARIFICATION OF METHODOLOGY 

FOR CALCULATING POTENTIAL TO EMIT (PTE) 

FOR BATCH CHEMICAL PRODUCTION OPERATIONS 

I. BACKGROUND

In a January 25, 1995 memorandum, the Environmental

Protection Agency (EPA) addressed a number of issues related to

the determination of a source’s PTE under section 112 and title V

of the Clean Air Act (Act). One of the issues discussed in the

memorandum was the term “maximum capacity of a stationary source

to emit under its physical and operational design,” which is part

of the definition of “potential to emit.” The EPA is currently

conducting category-specific analyses to address issues related

to the application of the “maximum capacity” principle to

specific types of sources. This memorandum provides guidance on

determining the maximum capacity of batch chemical production

facilities to emit in light of physical limitations on the

operation of individual units at such facilities.

II. TECHNICAL GUIDANCE FOR BATCH CHEMICAL PRODUCERS

Batch chemical production operations are those in which raw

materials are charged into the system at the beginning of the

process, and the products are removed all at once at the end of

the process. The production occurs in discrete batches, rather

than as a continuous process in which raw materials are

continuously being fed, and products continuously being removed. 

Moreover, the addition of raw material and withdrawal of product

do not occur simultaneously in a batch operation. Systems in

batch chemical operations consist of various equipment such as re

actors, solid/liquid separators, dryers, distillation columns,

extraction devices, and crystalizers, arranged in a series. The

series (i.e., the particular equipment used and the sequence of

that equipment) and the utilization rate (i.e., the time each

piece of the equipment is in operation) may change with each

different product produced (i.e., each production cycle). Many

batch chemical facilities produce a wide variety of products.

Emissions from batch chemical production consist primarily

of volatile organic compounds (VOC) and individual volatile

organic hazardous air pollutants (HAP’s). For a given batch

production cycle which is used to produce a particular chemical

from a given set of raw materials, emissions will occur at

various unit operations in the production cycle. For a given

1
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--

--

production cycle, involving a specified set of raw materials,

products, and unit operations, emission estimation methods are

provided in an EPA document entitled Control of Volatile Organic

Emissions from Batch Process -- Alternative Control Techniques

Information Document (EPA-453/R-94-020, February 1994 (the Batch

ACT).

Operation units (reactors, etc.) at batch chemical plants

may not be dedicated to the production of a single chemical. 

Rather, the collection of operation units at a given plant site

is available to manufacture a variety of different chemicals. 

The determination of worst-case potential emissions from batch

chemical production at a given plant site, therefore, involve the

following steps:

Identification of the possible batch production cycles

that reasonably could be undertaken at the plant site

(i.e., determination of the equipment present, and the

chemicals that could be produced with that equipment);

For each batch cycle, determination of the VOC and

individual HAP emissions; and

Determination of the worst-case annual VOC and HAP

emissions, based upon the highest emitting combination

of batch production cycles that, given the facility’s

inherent inability to use one operations unit for more

than one production cycle at a time, could be

undertaken at the facility over a year’s time.

These steps are discussed in detail in a document prepared

by the Synthetic Organic Chemical Manufacturers Association

(SOCMA). This document is included here as Attachment 2. The

EPA believes that the SOCMA methodology is a reasonable procedure

to use for identifying worst-case potential emissions from a

given batch chemical production operation.

The EPA explicitly clarifies that in calculating the

potential to emit for batch chemical operations, it is not

necessary to determine the maximum emissions for a worst-case

hour of operation, and to multiply that value times 8760. It is

physically impossible for the process to sustain the worst-case

hourly emission rate over the entire batch and so the EPA deems

it appropriate to take into account variations in the emissions

rate over the course of the entire cycle. For this reason, in

this instance, worst-case emissions may be determined by deriving

an average rate over an entire production cycle and emissions may 

be calculated based on the greatest number of batches that could 

2
occur in a year’s time according to the methodology in

Attachment 2. 

The EPA’s approval of the methodology in Attachment 2 should

not be construed as precluding a source from proposing

alternative methodologies for calculating the PTE from batch

chemical operations.

III. USE OF THE GUIDANCE FOR DETERMINING MAJOR SOURCE

APPLICABILITY

A. List of Products that a Source is Capable of Producing 

The SOCMA methodology reflects the maximum emissions from

existing equipment given a list of chemicals to be manufactured

with the equipment and given the raw materials used to

manufacture those products. The list of products and raw

materials should include all products that the source, in the

exercise of due diligence and best engineering judgment,

reasonably knows that it can produce. 

The best engineering judgment regarding what a source is

capable of producing might consider, at a minimum:

1. Products that this source currently produces or has

produced in the past;

2. Products that this source reasonably can produce

without having to change the physical or operational

design of the source; and

3. Products that similar sources have produced.

However, the Agency acknowledges that a batch source cannot

reasonably evaluate whether it is capable of producing a

particular product (or what the emissions from producing that

product might be) without a certain level of process design

information. Accordingly, the Agency believes that a batch

source need only consider products for which, in the exercise of

due diligence, sufficient information is reasonably available to

generate a reasonable estimate of PTE for that product as it

might be produced at the source using the estimation methods

outlined in the Batch ACT.

For example, the question has been raised as to how to

perform a PTE calculation for chemicals that may not yet exist, 

3
for which there is no known use in commerce, or that may be

manufactured by others with similar equipment, but which the

source has attempted and failed to develop a process to

manufacture and so does not have sufficient information to

estimate potential emissions. The Agency’s response is that a

rule of reason applies in each of these instances and that the

PTE calculation need not include such chemicals. 

Exercising its best engineering judgment as to the products

that the source is capable of producing, a source would

ordinarily not consider the following types of products:

1. Products that would require a change in the physical

design of the source to produce;

2. Chemicals which cannot reasonably be produced, including

chemicals which cannot be reasonably produced in commercially

viable quantities, chemicals which are not sold in commerce, and

chemicals for which no commercial market is reasonably

foreseeable or for which there is no known use in commerce; and

3. Products which the source may have the theoretical

physical capacity to produce, but for which the source does not

have the technical knowledge necessary to produce that product

and cannot, through the exercise of reasonable due diligence,

obtain the requisite technical knowledge.

This is not an exhaustive list of methods that a best

engineering judgment regarding what a source is capable of

producing could include. However, a list of products identified

using these methods should provide a large enough list of

products that, while the source may have overlooked a particular

product that would be used as the worst-case product, it will

likely have included another product that results in an

equivalent PTE calculation.

Inherent in many of these determinations regarding the best

engineering judgment as to which products a source should, or

should not, include in its PTE analysis is a degree of decision

making by the source. The EPA believes that a source that

exercises due diligence in making these decisions under the

criteria identified above will generate a PTE amount that can be

relied on by both the source and permitting authorities in

determining whether the source is major under the Clean Air Act’s

requirements. There may be additional justification as to why a

particular product should or should not be included in the

engineering judgment of what a source is capable of producing. 

In making these engineering judgments, a source that is 

4
conservative in its assumptions and takes an inclusive view as to

which products it is capable of producing would have a greater

degree of certainty in its determination as to whether it is

major than a source that seeks to exclude products from its

determination. The source that takes a more conservative

approach would also be in a much better position to convince an

enforcement authority that its determination regarding the

products that it could produce was within the boundaries of its

best engineering judgment. The Agency believes that it is in the

source’s best interest to be inclusive rather than exclusive in

evaluating the worst-case set of chemicals that may be produced.

Clearly, however, whether or not the source is justified in 

excluding a particular product from its initial PTE calculation, 

before manufacturing any product not included in the PTE 

calculation, the source must reevaluate its PTE estimate and 

obtain any required permits or permit revisions. Such permitting 

actions might include modifications of major or minor source 

preconstruction permits. 

B. Minor/Major Determination 

Sources that have taken a conservative approach in

exercising their engineering judgment regarding the products that

they are capable of producing, and applied the SOCMA methodology

to these products and determined that their PTE is below a major

threshold level should be confident that they are an area source. 

A rule of reason applies to the degree of rigor to be employed in

performing the analysis. For a source that concludes its PTE is

just below the major source level, the EPA recommends that the

source document any assumptions used in the engineering analysis,

and that it exercise caution not to exclude products appropriate

for inclusion under the criteria discussed above. This is

particularly important when a facility has relied on a small

number of products in its analysis as the possibility that an

overlooked product could affect PTE calculations is higher in

this instance than if the source had used a large number of

products in its PTE analysis.

For sources with PTE calculations over major threshold

levels, sources can also avoid major source status by obtaining

permits that limit their PTE to minor levels. These synthetic

minor permits can either specify the products that a source is

authorized to produce or restrict the source from producing

specific products that it is otherwise capable of producing. 

Sources that have calculated their PTE at amounts just under a

major source threshold level may also want to obtain permits with

emission levels that protect them from being classified as major

5
to avoid having to recalculate PTE as new products are developed

or in the event that their engineering judgment regarding the

products that they were capable of producing was in error.

C. Changes in What a Source is Capable of Producing 

The situation may arise where a source learns that it is

capable of producing a product that was not included in its

engineering analysis at the time that the PTE calculation was

performed. If this new product would raise a source’s calculated

PTE, and particularly where it would raise the source’s

calculated PTE from below major levels to above major levels, the

source may have to make appropriate changes to any permit that it

currently holds or obtain an entirely new permit. If the PTE

will exceed that of a major source, the facility must then comply

with all applicable major source requirements. However if this

new product would not affect the “worst-case” PTE calculation

that the source has already performed, no further actions would

be required pursuant to Federal requirements although State

requirements may require that the source take some action such as

changing its permit terms to reflect the new product.

On the other hand, where a citizen or an enforcement

authority demonstrates that the source was reasonably capable of

producing the new product all along, the source could be found in

violation back until the point in time at which an engineering

judgment would have shown that the facility was reasonably

capable of making this product. The Agency has published general

guidance concerning good faith assumptions in potential to emit

permitting. See the June 13, 1989 memorandum, “Guidance on

Limiting Potential to Emit in New Source Permitting.”

IV. CONSIDERATION OF ADDITIONAL SOURCES

The methodology in Attachment 2 relates only to emissions

from batch chemical production operations. Additional sources

may be present at a batch chemical plant and, if so, potential

emissions from such sources should be taken into account in

determining the facility’s potential to emit.

6
Attachment 2.


HOW TO CALCULATE POTENTIAL EMISSIONS FROM A BATCH PROCESS TO


DETERMINE MAJOR SOURCE STATUS 


UNDER THE CLEAN AIR ACT 


1.0 Introduction


2.0 Five (5) Step PTE Emission Estimation Methodology


2.1 ACT Derived AERs


2.2 Percent Equipment Utilization


2.3 Interchangeable Equipment Determinations


2.4 Data Tabulation


2.5 Selection of PTE


3.0 Model PTE Calculations


SECTION 1.0--INTRODUCTION


In January 1995, the Agency published guidance on several


issues related to “potential to emit” (PTE). The Agency stated


at that time that it would issue additional category-specific


technical assistance and guidance on PTE issues. 


The following guidance is being issued to assist sources


that must calculate potential emissions from batch processes. 


The calculation of potential emissions from these facilities must


consider equipment utilization rates for each product/process and


their relationship to one another. The methodology is based on


equipment utilization rates and the constraints that exist in


using limited equipment to produce a finite list of manufactured


products.


The following methodology provides for documentation of both


the products manufactured and the equipment used to manufacture


these products. The methodology begins with the largest emitting


product/process and methodically rules out other processes that


cannot be manufactured at the same time. The facility should


maintain the documentation required to perform this analysis as


part of its routine recordkeeping.


SECTION 2 - EMISSION ESTIMATION METHODOLOGIES


The following five step procedure should be followed to


calculate potential to emit to determine if a batch


7
--------------------------------------------------

processing facility is a major source. Each step is


described below.


SECTION 2.1 - CALCULATION OF PRODUCT SPECIFIC ANNUAL EMISSION


RATES FOR SPECIFIC EQUIPMENT TRAINS NEEDED TO PRODUCE SPECIFIC


PRODUCTS (STEP #1)


The USEPA's 1994 Alternatives Control Technology (ACT)


Document contains several equations for calculating


emissions for various types of batch operations. In


addition, the ACT Document implies that the following


methodology should be used for converting these emission


calculations to Annual Emission Rates (AER):


Equation 2.1:


(AER) Product M, Pollutant X =


[ACT Derived Total Emissions Per Batch x 8760 Hours/Yr] 


[Time in hours required for the piece of equipment in The


Batch Train that is used the most]


Where AER = Annual Emission Rate for Pollutant X for Product


M to be produced in a specific batch train. (It should be


noted that the above calculation assumes that Product M is


the only product produced in the batch train.)


To complete Step 1, calculate the AER values for every


pollutant regulated by the Clean Air Act for every batch


train needed to produce a specific product.


8
-------------------------------------------

SECTION 2.2 - CALCULATION OF EQUIPMENT UTILIZATION PERCENTAGES


FOR EACH PIECE OF EQUIPMENT IN THE BATCH TRAIN NEEDED TO PRODUCE


A SPECIFIC PRODUCT (STEP #2)


Step 2 of the PTE analysis can be completed by


extracting from batch sheets the time needed to run each


piece of equipment in every batch train. The following


equation should be used to calculate percent utilization


(i.e., percentage of time required for every piece of


equipment for every product which can be produced in the


batch train):


Equation 2.2:


Percent Utilization Product M =


[100% x (Time in hours of individual piece of


equipment)] 


[Maximum hours for piece of equipment with the


largest time]


For this example, the batch train for hypothetical


Product H consists of a reactor, a centrifuge, and a


dryer. Reaction, centrifugation, and drying times for


Product H are 120, 240, and 120 hours, respectively. 


Therefore, using Equation 2.2, the percent utilization


for the reactor is:


100% x 120/240, or 50%.


Similarly, percent utilizations for the centrifuge and


dryer are 100% and 50%, respectively. 


SECTION 2.3 - DETERMINATIONS INVOLVING INTERCHANGEABLE


EQUIPMENT (STEP #3)


To complete Step 3, identify interchangeable or


alternative equipment which can be substituted for


equipment normally used to make a particular product by


examining batch sheets. For this example, note that


reactor R-6B and centrifuge C-4 can be substituted for


reactor R-5 and centrifuge C-5.


9
SECTION 2.4 - TABULATION OF AER, PERCENT


UTILIZATION, AND INTERCHANGEABLE EQUIPMENT


DETERMINATIONS (STEP #4)


Step 4 can be completed by recording, in a Batch


Percent Utilization/Emission spreadsheet, the AER values


(from Step 1) for each product that emits a regulated


pollutant. In the same spreadsheet, record percent


utilization (Step 2) for each piece of equipment which


makes up the batch train for a specific product and also


indicate interchangeable equipment (Step 3). It should


be noted that separate spreadsheets must be filled out


for each hazardous air pollutant (HAP) and for each


criteria pollutant. Examples are provided in Section 3


of this manual to help the user complete Step 4 of the


procedure. 


SECTION 2.5 - SELECTION OF PTE (STEP #5)


SECTION 2.5.1 - PTE FOR A SINGLE PIECE OF BATCH


PROCESSING EQUIPMENT


PTE for a batch process which requires only a single


piece of equipment (e.g., one reactor) is equal to the


worst case Annual Emission Rate (AER) for that piece of


equipment. Worst case AER is determined by first


computing AER values for every product which can be


produced in this piece of equipment and then by selecting


the highest AER value. To summarize, PTE for a single


piece of equipment is equal to the highest AER value and


assumes that the product with the highest AER value will


be the only product produced in that piece of equipment.


SECTION 2.5.2 - PTE FOR OTHER BATCH PROCESSING FACILITIES


PTE for batch processing facility with more than one


piece of equipment must be determined by completing Step


5 of this procedure. To complete Step 5, examine the


emissions and percent utilization data for each matrix


generated in Step 4 and select maximum emissions for each


pollutant by fully utilizing all available equipment


which can be used to produce a particular product. Do


not exceed 100% utilization for any piece of equipment. 


The examples in Section 3.0 will teach the user how to


fill out a Batch PTE Spreadsheet. 


10
SECTION 3 - MODEL PTE CALCULATIONS


A hypothetical custom chemical batch processing


facility has 23 point sources which emit 3 HAPs (toluene,


methanol and hexane) and one criteria pollutant (VOCs)


during the manufacture of 20 products (identified as


letters A through T.) To determine the applicability of


Clean Air Act requirements such as Title V permitting,


Reasonably Available Control Technology (RACT) standards,


and Section 112 (g) for future modifications, this


facility must determine its potential to emit and wishes


to use the recommended calculation procedures.


3.1 Calculation of Toluene PTE


By following the calculation procedures and


completing the Batch Percent Utilization Spreadsheet


described in Section 2.4 above, we can see that, as


indicated in Table 1A, toluene can be emitted from 7


batch reactors, 3 batch dryers, 2 batch centrifuges, and


1 thin film evaporator. Toluene is emitted in the


production of 7 different products.


Product G is the largest emitter of toluene and


requires batch reactor R-5 for the entire batch time


(i.e., 100% utilization). Since reactors R-5 and R-6B


are interchangeable, the maximum toluene emissions for


process G is two (2) times the toluene emission rate for


one train or 2 x 3.92 = 7.84 TPY. By making this worst


case selection, we have tied up both reactors R-5 and R-


6B 100% of the time. Therefore, no other process can be


run or considered that requires these reactors. 


Consequently, only Processes C and F can be run


concurrently with Process G since all other products


require reactors R-5 or R-6B. By inspection, there is no


equipment conflict between C and F, so they can be


operated concurrently 100% of the time. Therefore, their


toluene emissions are added to twice G's emissions to


calculate a total toluene plant-wide potential to emit of


9.1 ton/year (see Batch PTE Spreadsheet Table 1B which


also serves as a final equipment conflict check).


3.2 Calculation of Methanol PTE


As indicated in Table 2A, methanol can be emitted


from 7 reactors, 3 centrifuges, 1 thin film evaporator, 4


dryers, and 2 ion exchange units. Methanol is emitted in


the production of 9 different products.


11
By reviewing that Batch Percent Utilization


Spreadsheet, we can see that Product H is the largest


emitter of methanol and requires 1 batch reactor (R-5)


50% of the time, 1 dryer (D-4) 50% of the time, and 1


centrifuge (C-4) 100% of the entire batch time. However,


reactor R-5 and dryer D-4 can be run 100% of the time if


both centrifuges C-4 and C-5 are used. The maximum


methanol emissions for Product H would then be two (2)


times the methanol emission rate for one train (2 x 3.2 =


6.4 TPY).


By making this worst case assumption, we have tied 

up reactor R-5, centrifuges C-4 and C-5, and dryer D-4 

100% of the time. Therefore, no other process can be run 

or considered that requires this equipment. 

Consequently, by inspection of Table 2A, Product J can be 

eliminated because it uses centrifuges C4 and C5. 

Process J*s use of reactor R-5 would not itself eliminate 

process J because reactor R-6B is interchangeable. 

Product L can be eliminated because it uses centrifuge 

C5. Products I and O can be eliminated because they both 

require centrifuge C-4. 

The highest methanol emitter for remaining processes


(Products E, K, M and N) is Process K which requires


reactor R-1, centrifuge C-2 and dryer D-6. Including


Process K in the PTE calculation eliminates Products M


and N which, respectively, utilize reactor R-1 and dryer


D-6.


The only remaining methanol emitter is Process E


which uses reactor R-5. Since reactor R-6B is available,


Process E is included in the total methanol PTE 


calculations. Therefore, the methanol potential to emit


can be calculated by summing emissions from Processes E,


H, and K and is equal to 1.0 + 6.4 + 1.9 or 9.3 TPY


(Table II-B).


3.3 Calculation of Hexane PTE


As indicated in Table 3A, hexane can be emitted from


8 batch reactors, 2 batch centrifuges, 1 still, 1 thin


film evaporator, and 3 dryers. Hexane is emitted in the


production of 9 different products.


By reviewing that Batch Percent Utilization


Spreadsheet, we can see that Product S is the largest


emitter of hexane and requires reactor R-1 and centrifuge


12
C-4 100% of the time. Therefore, no other process can be


considered that requires this equipment. Consequently,


Products D, I, L, Q, and R can be eliminated because they


all use reactor R-1.


By inspection, we can see that Product T is the next


largest emitter of hexane and should be included in the


total hexane PTE because it requires reactor R-6B 100% of


the time. However, since reactor R-5 can also be used to


produce Product T and there is "spare" capacity in both


centrifuge C-5 and dryer D-1, an additional 13% of the


time T can be run using reactor R-5. This limits out


dryer D-1 at 100% of capacity. Therefore, dryer D-1 is at


94% utilization for Product T and centrifuge C-5 is at 33%


utilization total (i.e., basic yearly batch x 1.13).


Product P is eliminated because there is 100 %


utilization of dryer D-1 in making Products S and T. 


Since there is capacity in centrifuge C-5 to produce


Product U concurrently with Products S and T, its


emissions should be counted in the final hexane plant-wide


PTE along with emissions from products S and T.


3.4 Calculation of Total HAP PTE


The total HAP PTE should be determined by first


identifying the product with the largest (HAP) emission


rate. In this case, Product S has the largest (HAP)


emission rate (4.05 TPY of hexane) and fully utilizes


reactors R-1 and centrifuge C-4. However, the third


largest emitter of HAP is Product H which emits 3.2 TPY of


methanol and which uses 50% of reactor R-5's, 100% of


centrifuge C-4's, and 50% of dryer D-4's capacity. Product


H's methanol emissions would be 6.4 TPY if reactor R-5,


centrifuges C-4 and C-5, and dryer D-4 are run at 100%


capacity. Since Product S's emissions are less than


Product H's at full equipment utilization, Product H should


be selected and Product S emissions should be eliminated


from the worst case PTE calculation. Therefore, reactor R-


5 and centrifuges C-4 and C-5, and dryer D-4 are fully


utilized. Any product using any one of these pieces of


equipment other than reactor R-5 can be eliminated from the


total HAP PTE calculation (Products A, C, D, I, J, L, O, P,


Q, S, T and U).


The second largest emitter of a HAP is Product G which


can utilize reactor R-6B and which emits 3.92 TPY of


toluene. Since there are no equipment conflicts, its HAP


emissions will be included in the total plant-wide HAP PTE.


13
Products B (2.44 TPY toluene) and E (1.0 TPY methanol)


are eliminated from the total HAP PTE calculation because


they use reactors R-5 or R-6B, which are fully utilized to


make Products G and H.


The next largest emitter of a HAP is Product K which


emits 1.86 TPY of methanol and which fully utilizes reactor


R-1 and dryer D-6. Since this equipment is not used to


make Products G and H, Product K's emissions should be


included in the total worst case HAP PTE calculation.


Products R is eliminated from the total HAP PTE


calculation because it uses reactor R-1.


Product M (10.55 TPY methanol) is eliminated because


it uses reactor R-1.


Products F and N are eliminated because they use dryer


D-6 which is tied up in the production of Product K.


Therefore, the total HAP PTE is 12.2 TPY and is 


determined by adding emissions from Products G (3.9 TPY


toluene), Product H (6.4 TPY methanol), and Product K (1.86


TPY methanol).


14
Table IA 

PROCESSES WITH MAXIMUM TOLUENE EMISSIONS 

* R-5 and R-6B interchangeable; C-4 and C-5 interchangeable 

PRODUCT A B C D E F G 

AER (TPY) 0.11 2.44 0.67 1.35 1.84 0.56 3.92 

EQUIPMENT PERCENT UTILIZATION 

R-1 64.00 23.00 

R-3 44.00 

R-4 74.00 

*R-5 50.00 100.00 100.00 100.00 

R-6A 

*R-6B 100.00 100.00 

R-7 

R-8 48.00 

R-12 24.00 

C-2 

*C-4 100.00 15.00 39.00 

*C-5 50.00 

S-1 

S-2 

S-4 

L-1 52.00 100.00 36.00 

D-1 44.00 16.00 

D-2 53.00 

D-4 

D-5 

D-6 50.00 100.00 

IE-1 

IE-2 

R = reactor; C= centrifuge; S= distillation unit; L = thin film evaporator; D= dryer; IE = ion exchange 

15
TABLE IB

TOLUENE POTENTIAL TO EMIT (PTE)

PRODUCT G C F TOTALS 

EMISSIONS (TPY) 7.84 0.67 0.56 9.07 

EQUIPMENT PERCENT UTILIZATION 

R-5 100.00 100.00 

R-6B 100.00 100.00 

D-6 100.00 100.00 

R-3 44.00 44.00 

C-4 15.00 15.00 

L-1 100.00 100.00 

D-1 44.00 44.00 

16
TABLE IIA 

PROCESSES WITH MAXIMUM METHANOL EMISSIONS 

* R-5 and R-6B are interchangeable; C-4 and C-5 are interchangeable 

PRODUCT E H I J K L M N O 

AER (TPY) 1 3.22 0.24 1.58 1.86 0.21 0.55 0.53 0.6 

EQUIPMENT PERCENT UTILIZATION 

R-1 57.00 100.00 82.00 43.00 65.00 

R-3 100.00 

R-4 

*R-5 100.00 50.00 40.00 100.00 30.00 

R-6A 20.00 

*R-6B 44.00 

R-7 

R-8 100.00 100.00 

R-12 24.00 42.00 41.00 

C-2 83.00 33.00 71.00 15.00 

*C-4 100.00 57.00 42.00 10.00 

*C-5 42.00 47.00 

S-1 

S-2 

S-4 

L-1 36.00 

D-1 100.00 35.00 43.00 

D-2 

D-4 50.00 

D-5 72.00 

D-6 79.00 100.00 100.00 100.00 

IE-1 67.00 90.00 

IE-2 90.00 

17
TABLE IIB

METHANOL POTENTIAL TO EMIT (PTE)

PRODUCT H K E TOTALS 

EMISSIONS (TPY) 6.44 1.86 1.0 9.3 

EQUIPMENT PERCENT UTILIZATION 

R-1 100.00 100.00 

R-5 100.00 100.00 

R-6B 100.00 100.00 

R-12 24.00 24.00 

C-2 33.00 33.00 

C-4 100.00 100.00 

C-5 100.00 100.00 

D-4 100.00 100.00 

D-6 100.00 100.00 

L-1 36.00 36.00 

18
TABLE IIIA 

PROCESSES WITH MAXIMUM HEXANE EMISSIONS 

* R-5 and R-6B are interchangeable; C-4 and C-5 are interchangeable. 

PRODUCT D I L P Q R S T U 

AER (TPY) 2.13 0.73 1.83 0.59 1.2 1.02 4.05 3 0.33 

EQUIPMENT PERCENT UTILIZATION 

R-1 23.00 57.00 82.00 100.00 92.00 100.00 

R-3 100.00 45.00 92.00 70.00 

R-4 38.00 9.00 

*R-5 100.00 100.00 57.00 

R-6A 

*R-6B 44.00 100.00 

R-7 

R-8 9.00 100.00 

R-12 41.00 100.00 

C-2 

*C-4 39.00 57.00 100.00 44.00 100.00 29.00 48.00 

*C-5 47.00 14.00 

S-1 92.00 

S-2 

S-4 

L-1 92.00 

D-1 16.00 35.00 100.00 6.00 83.00 

D-2 

D-4 91.00 

D-5 

D-6 79.00 12.00 

IE-1 

IE-2 

19
TABLE IIIB

HEXANE POTENTIAL TO EMIT

PRODUCT S T U TOTALS 

EMISSIONS (TPY) 4.05 3.4 0.33 7.8 

EQUIPMENT PERCENT UTILIZATION 

R-1 100.00 100.00 

R-3 70.00 70.00 

R-5 57.00 13.00 70.00 

R-6B 100.00 100.00 

R-7 

R-8 100.00 100.00 

C-4 100.00 100.00 

C-5 14.00 33.00 48.00 95.00 

D-1 6.00 94.00 100.00 

D-4 91.00 91.00 

20
TABLE IV

TOTAL HAP POTENTIAL TO EMIT

PRODUCT H G K TOTALS 

EMISSIONS (TPY) 6.44 3.92 1.86 12.22 

EQUIPMENT PERCENT UTILIZATION 

R-1 100.00 100.00 

R-3 

R-4 

R-5 100.00 100.00 

R-6A 

R-6B 100.00 100.00 

R-7 

R-8 

R-12 

C-2 33.00 33.00 

C-4 100.00 100.00 

C-5 100.00 100.00 

S-1 

S-2 

S-4 

L-1 

D-1 

D-2 

D-4 100.00 100.00 

D-5 

D-6 100.00 100.00 

IE-1 

IE-2 

21