52426 Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 

For the reasons discussed in the 

preamble, the Coast Guard proposes to 

amend 33 CFR part 117 as follows: 

PART 117—DRAWBRIDGE 

OPERATION REGULATIONS 

1. The authority citation for part 117 

continues to read as follows: 

Authority: 33 U.S.C. 499; 33 CFR 1.05–1; 

Department of Homeland Security Delegation 

No. 0170.1. 

2. In § 117.217, revise paragraph (b) to 

read as follows: 

§ 117.217 Norwalk River. 

* * * * * 

(b) The Metro-North WALK Bridge at 

mile 0.1, across the Norwalk River, at 

Norwalk, Connecticut shall operate as 

follows: 

(1) The draw shall open on signal 

between 4:30 a.m. and 9 p.m. after at 

least a two hour advance notice is given; 

except that, from 4:30 a.m. through 9:30 

a.m. and from 4 p.m. through 9 p.m., 

Monday through Friday excluding 

holidays, the draw need not open for the 

passage of vessel traffic unless an 

emergency exists. 

(2) From 9 p.m. through 4:30 a.m. the 

draw shall open on signal after at least 

a four hour advance notice is given. 

(3) A delay in opening the draw not 

to exceed 10 minutes may occur when 

a train scheduled to cross the bridge 

without stopping has entered the 

drawbridge lock. 

(4) Requests for bridge openings may 

be made by calling the bridge via marine 

radio VHF FM Channel 13 or the 

telephone number posted at the bridge. 

Dated: August 20, 2015. 

L.L. Fagan, 

Rear Admiral, U.S. Coast Guard, Commander, 

First Coast Guard District. 

[FR Doc. 2015–21531 Filed 8–28–15; 8:45 am] 

BILLING CODE 9110–04–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Parts 60, 61 and 63 

[EPA–HQ–OAR–2014–0738; FRL–9933–16– 

OAR] 

Notice of Final Approval for the 

Operation of Pressure-Assisted MultiPoint Ground Flares at The Dow 

Chemical Company and ExxonMobil 

Chemical Company and Notice of 

Receipt of Approval Request for the 

Operation of a Pressure-Assisted 

Multi-Point Ground Flare at Occidental 

Chemical Corporation 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Notice; approval and request for 

comments. 

SUMMARY: This notice announces our 

approval of the Alternative Means of 

Emission Limitation (AMEL) requests 

for the operation of multi-point ground 

flares (MPGF) at The Dow Chemical 

Company’s (Dow) Propane 

Dehydrogenation Plant and Light 

Hydrocarbons Plant located at its Texas 

Operations site in Freeport, Texas, and 

the ExxonMobil Chemical Company 

(ExxonMobil) Olefins Plant in Baytown, 

Texas, and its Plastics Plant in Mont 

Belvieu, Texas. This approval notice 

also specifies the operating conditions 

and monitoring, recordkeeping, and 

reporting requirements for 

demonstrating compliance with the 

AMEL that these facilities must follow. 

In addition, this notice solicits 

comments on an all aspects of an AMEL 

request from Occidental Chemical 

Corporation (OCC) in which long-term 

MPGF burner stability and destruction 

efficiency have been demonstrated on 

different pressure-assisted MPGF 

burners that OCC has proposed for use 

in controlling emissions at its Ingleside, 

Texas, ethylene plant. 

Lastly, this notice presents and 

solicits comments on all aspects of a 

framework of both MPGF burner testing 

and rule-specific emissions control 

equivalency demonstrations that we 

anticipate, when followed, would afford 

us the ability to approve future AMEL 

requests for MPGF in a more efficient 

and streamlined manner. 

DATES: The AMEL for the MPGF at 

Dow’s Propane Dehydrogenation Plant 

and Light Hydrocarbons Plant located at 

its Texas Operations site in Freeport, 

Texas, and ExxonMobil’s Olefins Plant 

in Baytown, Texas, and Plastics Plant in 

Mont Belvieu, Texas are approved and 

effective August 31, 2015. 

Comments. Written comments on the 

AMEL request from OCC for their MPGF 

in Ingleside, Texas, or on the framework 

for streamlining future MPGF AMEL 

requests must be received on or before 

October 15, 2015. 

Public Hearing. Regarding the OCC 

MPGF in Ingleside, Texas, or the 

framework for streamlining future 

MPGF AMEL requests, if requested by 

September 8, 2015, we will hold a 

public hearing on September 15, 2015, 

from 1:00 p.m. [Eastern Standard Time] 

to 8:00 p.m. [Eastern Standard Time] in 

Corpus Christi, Texas. We will provide 

details on the public hearing on our 

Web site at: http://www.epa.gov/ttn/

atw/groundflares/groundflarespg.html. 

To be clear, a public hearing will not be 

held unless someone specifically 

requests that the EPA hold a public 

hearing regarding the OCC MPGF or the 

framework for streamlining future 

MPGF AMEL requests. Please contact 

Ms. Virginia Hunt of the Sector Policies 

and Programs Division (E143–01), Office 

of Air Quality Planning and Standards, 

Environmental Protection Agency, 

Research Triangle Park, NC 27711; 

telephone number: (919) 541–0832; 

email address: hunt.virginia@epa.gov; to 

request a public hearing, to register to 

speak at the public hearing or to inquire 

as to whether a public hearing will be 

held. The last day to pre-register in 

advance to speak at the public hearing 

will be September 14, 2015. 

ADDRESSES: Submit your comments, 

identified by Docket ID Number EPA– 

HQ–OAR–2014–0738, to the Federal 

eRulemaking Portal: http://

www.regulations.gov. Follow the online 

instructions for submitting comments. 

Once submitted, comments cannot be 

edited or withdrawn. The EPA may 

publish any comment received to its 

public docket. Do not submit 

electronically any information you 

consider to be Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Multimedia submissions (audio, video, 

etc.) must be accompanied by a written 

comment. The written comment is 

considered the official comment and 

should include discussion of all points 

you wish to make. The EPA will 

generally not consider comments or 

comment contents located outside of the 

primary submission (i.e., on the web, 

cloud, or other file sharing system). For 

additional submission methods, the full 

EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

http://www2.epa.gov/dockets/

commenting-epa-dockets. 

Instructions. Direct your comments on 

the OCC MPGF or the framework for 

streamlining future MPGF AMEL 

requests to Docket ID Number EPA–HQ– 

OAR–2014–0738. The EPA’s policy is 

that all comments received will be 

included in the public docket without 

change and may be made available 

online at http://www.regulations.gov, 

including any personal information 

provided, unless the comment includes 

information claimed to be confidential 

business information (CBI) or other 

information whose disclosure is 

restricted by statute. Do not submit 

information that you consider to be CBI 

or otherwise protected through http://

www.regulations.gov or email. Send or 

deliver information identified as CBI 

only to the following address: OAQPS 

Document Control Officer (C404–02), 


rmajette on DSK7SPTVN1PROD with PROPOSALS
Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 52427 

Office of Air Quality Planning and 

Standards, U.S. Environmental 

Protection Agency, Research Triangle 

Park, North Carolina 27711, Attention: 

Docket ID Number EPA–HQ–OAR– 

2014–0738. Clearly mark the part or all 

of the information that you claim to be 

CBI. For CBI information on a disk or 

CD–ROM that you mail to the EPA, 

mark the outside of the disk or CD–ROM 

as CBI and then identify electronically 

within the disk or CD–ROM the specific 

information that is claimed as CBI. In 

addition to one complete version of the 

comment that includes information 

claimed as CBI, a copy of the comment 

that does not contain the information 

claimed as CBI must be submitted for 

inclusion in the public docket. 

Information so marked will not be 

disclosed except in accordance with 

procedures set forth in 40 CFR part 2. 

The http://www.regulations.gov Web 

site is an ‘‘anonymous access’’ system, 

which means the EPA will not know 

your identity or contact information 

unless you provide it in the body of 

your comment. If you send an email 

comment directly to the EPA without 

going through http://

www.regulations.gov, your email 

address will be automatically captured 

and included as part of the comment 

that is placed in the public docket and 

made available on the Internet. If you 

submit an electronic comment, the EPA 

recommends that you include your 

name and other contact information in 

the body of your comment and with any 

disk or CD–ROM you submit. If the EPA 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, the EPA may not 

be able to consider your comment. 

Electronic files should not include 

special characters or any form of 

encryption and be free of any defects or 

viruses. For additional information 

about the EPA’s public docket, visit the 

EPA Docket Center homepage at: http:// 

www.epa.gov/dockets. 

Docket. The EPA has established a 

docket for this action under Docket ID 

Number EPA–HQ–OAR–2014–0738. All 

documents in the docket are listed in 

the regulations.gov index. Although 

listed in the index, some information is 

not publicly available, e.g., CBI or other 

information whose disclosure is 

restricted by statute. Certain other 

material, such as copyrighted material, 

is not placed on the Internet and will be 

publicly available only in hard copy. 

Publicly available docket materials are 

available either electronically in 

regulations.gov or in hard copy at the 

EPA Docket Center (EPA/DC), EPA WJC 

West Building, Room 3334, 1301 

Constitution Ave. NW., Washington, 

DC. The Public Reading Room is open 

from 8:30 a.m. to 4:30 p.m., Monday 

through Friday, excluding legal 

holidays. The telephone number for the 

Public Reading Room is (202) 566–1744, 

and the telephone number for the EPA 

Docket Center is (202) 566–1742. 

FOR FURTHER INFORMATION CONTACT: For 

questions about this action, contact Mr. 

Andrew Bouchard, Sector Policies and 

Programs Division (E143–01), Office of 

Air Quality Planning and Standards 

(OAQPS), U.S. Environmental 

Protection Agency, Research Triangle 

Park, North Carolina 27711; telephone 

number: (919) 541–4036; fax number: 

(919) 541–0246; and email address: 

bouchard.andrew@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Acronyms and Abbreviations 

We use multiple acronyms and terms 

in this notice. While this list may not be 

exhaustive, to ease the reading of this 

notice and for reference purposes, the 

EPA defines the following terms and 

acronyms here: 

AMEL alternative means of emission 

limitation 

Btu/scf British thermal units per standard 

cubic feet 

CAA Clean Air Act 

CFR Code of Federal Regulations 

CPMS continuous parameter monitoring 

system 

EPA Environmental Protection Agency 

ESL effects screening level 

FR Federal Register 

HAP hazardous air pollutants 

LEL lower explosive limit 

LFL lower flammability limit 

LFLcz combustion zone lower flammability 

limit 

MPGF multi-point ground flare 

NESHAP national emission standards for 

hazardous air pollutants 

NHV net heating value 

NHVcz combustion zone net heating value 

NSPS new source performance standards 

OAQPS Office of Air Quality Planning and 

Standards 

OCC Occidental Chemical Corporation 

OSHA Occupational Safety and Health 

Administration 

PDH propane dehydrogenation unit 

PFTIR passive Fourier transform infrared 

spectroscopy 

psig pounds per square inch gauge 

QA quality assurance 

QC quality control 

TAC Texas Administrative Code 

TCEQ Texas Commission on Environmental 

Quality 

VOC volatile organic compounds 

Organization of This Document. The 

information in this notice is organized 

as follows: 

I. Background 

A. Summary 

B. Flare Operating Requirements 

C. Alternative Means of Emission 

Limitation 

II. Summary of Significant Public Comments 

on the AMEL Requests for PressureAssisted MPGF 

A. Regulatory Compliance Language and 

Calculation Methodology 

B. NHVcz and LFLcz Operating Limits and 

Averaging Time 

C. Monitoring Systems 

D. AMEL Mechanism and Process 

E. Other 

III. Final Notice of Approval of the AMEL 

Requests and Required Operating 

Conditions 

IV. Notice of AMEL Request for Occidental 

Chemical Corporation 

V. Notice of Framework for Streamlining 

Approval of Future Pressure-Assisted 

MPGF AMEL Requests 

I. Background 

A. Summary 

On February 13, 2015, the EPA 

published an initial notice in the 

Federal Register (FR) acknowledging 

receipt of AMEL approval requests for 

the operation of several MPGF at The 

Dow Chemical Company’s Dow Propane 

Dehydrogenation Plant and Light 

Hydrocarbons Plant located at its Texas 

Operations site located in Freeport, 

Texas, and ExxonMobil’s Olefins Plant 

in Baytown, Texas, and its Plastics Plant 

in Mont Belvieu, Texas (see 80 FR 8023, 

February 13, 2015). This initial notice 

also solicited comment on all aspects of 

the AMEL requests and the resulting 

alternative operating conditions that are 

necessary to achieve a reduction in 

emissions of volatile organic 

compounds (VOC) and organic 

hazardous air pollutants (HAP) at least 

equivalent to the reduction in emissions 

required by various standards in 40 CFR 

parts 60, 61 and 63 that apply to 

emission sources that would be 

controlled by these pressure-assisted 

MPGF. These standards point to the 

operating requirements for flares in the 

General Provisions to parts 60 and 63, 

respectively, to comply with the 

emission reduction requirements. 

Because pressure-assisted MPGF cannot 

meet the velocity requirements in the 

General Provisions, Dow and 

ExxonMobil requested an AMEL. This 

action provides a summary of comments 

received as part of the public review 

process, our responses to those 

comments, and our approval of the 

requests received from Dow and 

ExxonMobil for an AMEL for the MPGF 

at the specific plants listed above, along 

with the operating conditions they must 

follow for demonstrating compliance 

with the AMEL. 

This action also solicits comments on 

all aspects of an AMEL request from 

OCC in which MPGF burner stability 


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52428 Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 

1While Dow and ExxonMobil describe their flares 

as ‘‘pressure-assisted,’’ these flares qualify as ‘‘nonassisted’’ flares under 40 CFR 60.18(b) or 63.11(b) 

because they do not employ assist gas. 

2These requirements are not all inclusive. There 

are other requirements in 40 CFR 60.18 and 63.11 

relating to monitoring and testing that are not 

described here. 

3CAA section 111(h)(3) states: ‘‘If after notice and 

opportunity for public hearing, any person 

establishes to the satisfaction of the Administrator 

that an alternative means of emission limitation 

will achieve a reduction in emissions of any air 

pollutant at least equivalent to the reduction in 

emissions of such air pollutant achieved under the 

requirements of paragraph (1), the Administrator 

shall permit the use of such alternative by the 

source for purposes of compliance with this section 

with respect to such pollutant.’’ Section 112(h)(3) 

contains almost identical language. 

and destruction efficiency have been 

demonstrated on different pressureassisted MPGF burners that OCC has 

proposed for use in controlling 

emissions at its Ingleside, Texas, 

ethylene plant. 

Lastly, because we are aware that 

facilities plan to build or are 

considering use of MPGF as an 

emissions control technology, this 

action presents and solicits comments 

on all aspects of a framework for 

streamlining future MPGF AMEL 

requests that we anticipate, when 

followed, would afford the agency the 

ability to review and approve future 

AMEL requests for MPGF in a more 

efficient and expeditious manner. We 

note here though that all aspects of 

future AMEL requests would still be 

subject to a notice and comment 

proceeding. 

B. Flare Operating Requirements 

In their requests, Dow and 

ExxonMobil cited various regulatory 

requirements in 40 CFR parts 60, 61 and 

63 that will apply to the different flare 

vent gas streams that will be collected 

and routed to their pressure-assisted 

MPGF at each plant. These requirements 

were tabulated in the initial notice for 

this action (80 FR 8023, February 13, 

2015). The applicable rules require that 

control devices achieve destruction 

efficiencies of either 95 percent or 98 

percent either directly, or by reference, 

or allow control by flares meeting the 

flare operating requirements in 40 CFR 

60.18 or 40 CFR 63.11. The flare 

operating requirements in 40 CFR 60.18 

and 40 CFR 63.11 specify that flares 

shall be: (1) Steam-assisted, air-assisted 

or non-assisted; 1 (2) operated at all 

times when emissions may be vented to 

them; (3) designed for and operated 

with no visible emissions (except for 

periods not to exceed a total of 5 

minutes during any 2 consecutive 

hours); and (4) operated with the 

presence of a pilot flame at all times. 

The flare operating requirements in 40 

CFR 60.18 and 40 CFR 63.11 also 

specify requirements for both the 

minimum heat content of gas combusted 

in the flare and the maximum exit 

velocity at the flare tip.2 These 

provisions specify maximum flare tip 

velocities based on flare type (nonassisted, steam-assisted or air-assisted) 

and the net heating value of the flare 

vent gas (see 40 CFR 60.18(c)(3) and 40 

CFR 63.11(b)(6)). These maximum flare 

tip velocities are required to ensure that 

the flame does not ‘‘lift off’’ or separate 

from the flare tip, which could cause 

flame instability and/or potentially 

result in a portion of the flare gas being 

released without proper combustion. 

Proper combustion for flares is 

considered to be 98 percent destruction 

efficiency or greater for organic HAP 

and VOC, as discussed in our recent 

proposal titled ‘‘Petroleum Refinery 

Sector Risk and Technology Review and 

New Source Performance Standards,’’ 

79 FR 36880, 36904–36912 (June 30, 

2014). 

The MPGF proposed by both Dow and 

ExxonMobil are different in both flare 

head design and operation than the 

more traditional steam-assisted, airassisted and non-assisted flare types 

currently able to comply with the flare 

operating requirements in 40 CFR 60.18 

or 63.11. The MPGF technology operates 

by using the pressure upstream of each 

individual flare tip burner to enhance 

mixing with air at the flare tip due to 

high exit velocity, which in turn allows 

the MPGF to operate in a smokeless 

capacity. The MPGF are constructed 

differently than normal elevated flares 

in that they consist of many rows of 

individual flare tips which are 

approximately eight feet above ground 

level. The ground flare staging system 

opens and closes staging valves 

according to gas pressure such that 

stages containing multiple burners are 

activated as the flow and pressure 

increase or decrease in the header. 

While information supplied by Dow, 

and relied on by both Dow and 

ExxonMobil, indicates that the flare tips 

operate in a smokeless capacity and 

achieve high destruction efficiencies, 

the MPGF cannot meet the exit velocity 

requirements in 40 CFR 60.18 and 40 

CFR 63.11, which limit the exit velocity 

at the flare tip to a maximum of 400 feet 

per second. The exit velocities from 

MPGF typically range from 600 feet per 

second up to sonic velocity (which 

ranges from 700 to 1,400 feet per second 

for common hydrocarbon gases), or 

Mach = 1 conditions. As a result, Dow 

and ExxonMobil are seeking an 

alternative means of complying with the 

flare operating requirements in 40 CFR 

60.18 and 63.11; specifically, the exit 

velocity requirements in 40 CFR 

60.18(c)(3), (c)(4) and (c)(5) and in 40 

CFR 63.11(b)(6), (b)(7) and (b)(8). 

C. Alternative Means of Emission 

Limitation 

As noted above, the specific rules in 

40 CFR parts 60, 61 and 63, or the 

General Provisions for parts 60, 61 and 

63 of the Clean Air Act (CAA) 3 allow a 

facility to request an AMEL. These 

provisions allow the Administrator to 

permit the use of an alternative means 

of complying with an applicable 

standard, if the requestor demonstrates 

that the alternative achieves at least an 

equivalent reduction in emissions. The 

EPA provided notice of the requests and 

an opportunity for both a public hearing 

and opportunity for comment on the 

requests in the FR (see 80 FR 8023, 

February 13, 2015). After considering 

the comments received during the 

public comment period, the EPA is 

approving the AMEL requests and the 

use of the MPGF at Dow’s two plants at 

its Texas Operations site in Freeport, 

Texas, and at ExxonMobil’s two plants 

in Mont Belvieu, Texas, and Baytown, 

Texas. 

II. Summary of Significant Public 

Comments on the AMEL Requests for 

Pressure-Assisted MPGF 

This section contains a summary of 

the major comments and responses, and 

rationale for the approved MPGF 

operating conditions and monitoring, 

recordkeeping and reporting 

requirements necessary to ensure the 

MPGF will achieve a reduction in 

emissions of HAP and VOC at least 

equivalent to the reduction in emissions 

of other traditional flare systems 

complying with the requirements in 40 

CFR 60.18(b) and 40 CFR 63.11(b). 

A. Regulatory Compliance Language 

and Calculation Methodology 

Comment: Several commenters 

suggested that the EPA clarify the 

relationship between the AMEL and the 

requirements at 40 CFR 63.11 and 40 

CFR 60.18. Specifically, the commenters 

suggested that the EPA add the 

following or similar language: 

‘‘Compliance with applicable portions 

of 40 CFR 60.18 and 40 CFR 63.11, 

together with the AMEL, satisfy the new 

source performance standards (NSPS) 

and/or national emission standards for 

hazardous air pollutants (NESHAP) 

requirements that refer to 40 CFR 60.18 

and 40 CFR 63.11.’’ The commenters 

further state that adoption of this 

language would allow deletion of 

requirements #2 and #3 related to pilot 


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Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 52429 

flames, visible flames, and visible 

emissions standards in the initial AMEL 

notice. 

Response: First, we clarify here for 

both of Dow’s plants and both of 

ExxonMobil’s plants that will use MPGF 

as a control device that compliance with 

the requirements in Section III of this 

AMEL notice satisfies the flare NSPS 

and NESHAP requirements referenced 

in 40 CFR 60.18 and 40 CFR 63.11. 

However, we disagree with commenters 

that deletion of the language related to 

pilot flames and visible flames is 

appropriate given the unique design of 

MPGF installations and their various 

rows of hundreds of burners. The 

language currently in 40 CFR 60.18 and 

40 CFR 63.11 was intended to ensure 

that more traditional, individual flare 

tips had a flame present at all times by 

requiring that a pilot flame is always 

present. While having at least a single 

pilot flame is appropriate for a single 

flare tip, it in no way assures that each 

of the hundreds of flare tips that are 

arranged in multiple stages in a MPGF 

installation will ignite and have a flare 

flame when vent gas is sent to the 

system. Thus, we are not requiring Dow 

and ExxonMobil to comply with these 

requirements precisely as outlined 

currently in the General Provisions and 

are instead finalizing, based on 

information provided by these 

companies with respect to staging 

design and number of pilots per stage, 

a requirement in the AMEL that each 

stage of burners in the MPGF 

installation have at least two pilots with 

a continuously lit pilot flame. This 

requirement will provide the agency 

with a high level of assurance that a 

flare flame is present at all times when 

the other applicable requirements are 

also being met. 

Commenters also suggested that the 

language in the initial AMEL notice 

related to pilot flame presence at 

Section III, #2 (see 80 FR 8030, February 

13, 2015) had slightly different wording 

elements compared to the flare General 

Provisions requirements. We agree with 

the commenters that some of the 

language is different, but note that 

requiring at least two pilot flames on 

each stage of burners to be continuously 

lit and monitored as opposed to only a 

single pilot flame as prescribed in the 

General Provisions is a necessary 

change. However, we have incorporated 

language in this final action to be more 

consistent with the requirements in the 

General Provisions to allow pilot flames 

to be monitored by thermocouples ‘‘or 

any other equivalent device used to 

detect the presence of a flame.’’ 

Lastly, we agree with the commenters 

that the language in the initial AMEL 

notice related to visible emissions at 

Section III, #3 is somewhat redundant 

with the requirements in the General 

Provisions, but given that we are 

requiring facilities to use a video camera 

to conduct visible emissions 

observations we must address the 

visible emissions requirements 

specifically. 

Comment: Several commenters 

recommended that the EPA include in 

the final AMEL notice the equations and 

references to physical data needed to 

calculate NHVcz and LFLcz. 

Response: We agree with the 

commenters and are incorporating these 

changes in this final action. 

B. NHVcz and LFLcz Operating Limits 

and Averaging Time 

Comment: Several commenters 

suggested that the EPA should not set a 

precedent for potential future flare 

standards with respect to a 15-minute 

averaging period for the combustion 

parameters (i.e., NHVcz and LFLcz) or online monitoring technology. 

Commenters also suggested that the 

operating requirements of NHVcz of 800 

British thermal units per standard cubic 

foot (Btu/scf) or greater or LFLcz of 6.5 

percent by volume or less are based on 

the single worst-case data point, that 

this is not consistent with the Marathon 

Petroleum test report data, and that 

establishing a limit based on the single 

worst test run could set bad precedent 

for future potential flare and/or AMEL 

standards. 

Response: First, we note that flares by 

their very nature are designed to handle 

and combust highly variable waste gas 

flows and compositions. Given that both 

Dow and ExxonMobil have requested 

use of MPGF for applications in 

controlling emissions related to periods 

of upset, maintenance, startup and 

shutdown, the question for the Agency 

becomes how do these facilities 

demonstrate to the satisfaction of the 

Administrator that this AMEL will 

achieve a reduction in emissions of VOC 

and HAP at least equivalent to the 

reduction in emissions required by the 

various standards in 40 CFR parts 60, 61 

and 63 for highly variable flow and vent 

gas composition control scenarios. 

An assessment of the data we used to 

evaluate these AMEL requests suggests 

that at least an equivalent reduction in 

emissions control for MPGF has been 

demonstrated and can be maintained 

provided there is a stable, lit flame. In 

reviewing the supporting data, longterm stability was demonstrated by 20- 

minute test runs with fairly consistent 

flow and composition; however, there 

were also five test runs which showed 

instability in as little as 1 to 2 minutes. 

Considering that Dow and ExxonMobil 

will be producing and using olefins in 

their process, the Dow test is more 

appropriate and representative of the 

types of waste gas compositions and 

flows their MPGF will expect to handle 

compared to the natural gas and 

nitrogen mixtures burned in the 

Marathon test. Thus, the operating 

requirements of an NHVcz of 800 Btu/scf 

or greater or LFLcz of 6.5 percent by 

volume or less which come from the 

Dow test, while conservative, provides 

reasonable assurance that these 

particular sources will maintain a stable 

flame for consistent flows and waste gas 

compositions expected to be burned by 

these particular sources as opposed to a 

refiner like Marathon whose waste gas 

originates from a different source 

category. 

Finally, the available data we are 

using to assess what the appropriate 

averaging time should be for these 

unique MPGF installations indicate that 

there could exist a gap between the 

MPGF system response (e.g., the 

sampling of the waste gas stream and 

the introduction of supplemental fuel to 

counteract a low heat content waste gas 

stream) and flame stability for situations 

of highly variable flow and/or highly 

variable waste gas composition. In light 

of this, we considered reasonable 

options that provide assurance that 

these MPGF installations will control 

emissions at a high level of efficiency 

with a stable, lit flame during these 

particular events. In evaluating these 

options, we concluded that a short 

averaging time is necessary to ensure 

that the MPGF installations will work as 

intended. Given the fact that we are 

allowing use of on-line gas 

chromatographs to perform 

compositional analysis to determine 

compliance with the NHVcz and LFLcz

operating parameters, we cannot require 

shorter averaging times than the 

monitoring technology will allow, 

which is 15 minutes, and which we are 

finalizing in this action. In addition, we 

are also finalizing an alternative to 

allow the use of a calorimeter to monitor 

directly for NHVcz, which Dow or 

ExxonMobil may choose to use if they 

have similar concerns about variable 

flow/waste gas composition impacting 

flame stability, as these types of 

monitoring systems have significantly 

faster response times (e.g., 1 minute) 

than those of gas chromatographs. 

Lastly, we acknowledge the concerns 

presented with respect to setting 

precedent for potential future flare 

standards on averaging time and online 

monitoring technology. However, we 

note that this comment is beyond the 


rmajette on DSK7SPTVN1PROD with PROPOSALS
52430 Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 

4See ‘‘Multi-Point Ground Level Flare Modeling 

Discussion’’ at Docket ID Number EPA–HQ–OAR– 

2014–0738 for further information on modeling 

results. 

5See https://www.osha.gov/SLTC/

processsafetymanagement/ for more details. 

6See http://www2.epa.gov/rmp for more details. 

scope of this action and not relevant to 

the site-specific action of the AMEL 

requests for the use of MPGF at these 

specific Dow or ExxonMobil facilities. 

C. Monitoring Systems 

Comment: A number of commenters 

suggested that pressure and flow 

monitors on each stage of the MPGF are 

unnecessary, as the MPGF are not 

designed with pressure and flow 

monitors on each individual stage, but, 

rather, rely on the monitoring system on 

the main flare header that is used by the 

process control system to open and 

close various stages of the flare system. 

Commenters instead suggested that flow 

and pressure should be monitored on 

the main flare header, as well as valve 

position indicators showing whether the 

valves are open or closed for each 

staging valve. Another commenter 

agreed that flare header pressure was 

important, but questioned why the 

initial AMEL notice did not require a 

minimum flare header pressure set at 15 

pounds per square inch gauge (psig), 

since EPA stated that MPGF typically 

required 15 psig at the main flare header 

to properly operate. The commenter also 

suggested that the AMEL require 

monitoring of pressure at each stage and 

also set minimum flare header pressure 

requirements. 

Response: We agree that monitoring of 

flow and pressure on each individual 

stage is not needed as long as the flare 

header pressure and flow are adequately 

monitored. Given that the header 

pressure will be the maximum pressure 

at any point in the MPGF, the pressure 

of each stage will be at or lower than the 

main flare header pressure. As the 

commenters noted, the process control 

logic system opens and closes the 

staging valves based on the MPGF 

header pressure. Therefore, flare header 

pressure and information on which 

stages are open or closed will provide 

enough information to determine 

whether the MPGF is operating as 

designed. For example, if the pressure is 

low in the main flare header and below 

the minimum operating pressure of the 

burners in stage 2, the valve position 

indicator for stage 2 as well any valve 

position indicators for stages after stage 

2 should show that those stages are all 

closed. Both AMEL requests referenced 

the range of operating pressures of the 

burners/stages, and, therefore, this final 

AMEL requires that the MPGF burners 

be operated within the range of tested 

conditions or within the range of the 

manufacturer’s specifications, as 

demonstrated using header pressure and 

valve position indicators. We note that, 

while we discussed a typical flare 

header operating pressure in the 

technical memorandum supporting the 

initial AMEL notice and discussions 

(see memorandum ‘‘Review of Available 

Test Data on Multipoint Ground Flares’’ 

at Docket ID Number EPA–HQ–OAR– 

2014–0738–0002), we are providing the 

sites with a specific range of operating 

pressures to comply, as presented in 

their AMEL requests and supporting test 

data. 

Comment: One commenter suggested 

that the EPA should require each facility 

to install real-time fenceline monitoring 

to protect and inform communities if 

there is an increase in HAP crossing the 

fenceline during flaring events. The 

commenter stated that the proposed 

AMEL would allow operators to shift 

emissions from elevated flares to ground 

level, thus increasing ground-level 

pollution because emissions released at 

ground level, as compared to an 

elevated stack, do not disperse as far 

and remain in higher concentrations 

around the emitting source. The 

commenter stated that, as a result, the 

AMEL would increase exposure and risk 

and likely disproportionately impact 

minority and low income populations. 

Another commenter stated that based on 

dispersion modeling calculations 

conducted for the propane 

dehydrogenation unit (PDH) plant flare 

system, they project that the off-site 

concentrations of any air contaminant 

will be <1 percent of the TCEQ’s effects 

screening level (ESL) for both the shortterm one hour average concentrations 

and the annual averages.4 The 

commenter stated that these projected 

off-site impacts are similar to what is 

expected from an elevated flare. Given 

the low off-site concentrations 

predicted, it is the commenter’s opinion 

that additional ambient air monitoring 

is not warranted for this AMEL request. 

Other commenters suggested that flow 

and composition monitoring, in concert 

with monitoring for flame presence, 

would provide substantially more 

valuable information for evaluating the 

downwind effect of a flameout as 

compared to ambient monitoring. 

Another commenter suggested lower 

explosive limit (LEL) monitors around a 

ground flare could provide an 

indication of a malfunction or slow, 

unburned leaks from staging valves that 

the direct waste gases and flare monitors 

might miss. 

Response: Comments on additional 

monitoring of the ambient 

concentrations of pollutants in the 

atmosphere surrounding the ground 

flare address a range of concerns. Some 

comments relate to the efficiency of the 

flare and the emission potential of the 

flare when the ground flare is working 

as expected, and other comments relate 

to when the ground flare experiences 

flameout or some other event where 

uncombusted materials have the 

potential to be emitted. We agree that 

the combination of pilot flame 

monitoring in concert with flow and 

composition monitoring (and pressure/

staging valve monitoring) or use of LEL 

monitors in the immediate area of the 

ground flare are several methods the 

operator can use to identify an 

improperly-operating flare. However, if 

the suite of operating conditions being 

finalized in Section III below are met, 

we feel that the MPGF should operate 

properly and with a high level of 

destruction efficiency. Although we 

understand that the MPGF are equipped 

with safety interlocks and in some cases 

LEL monitors, we are not requiring they 

operate these systems under our final 

AMEL requirements for Dow and 

ExxonMobil. Rather, additional safety 

analyses should be addressed under the 

Occupational Safety and Health 

Administration’s (OSHA) Process Safety 

Management 5 and the EPA’s Risk 

Management Program.6 Regarding 

comments pertaining to the need for 

some type of monitoring for 

communities that may be impacted by 

these MPGF installations, we are not 

mandating any type of fenceline or 

community monitoring in the AMEL 

approval because the approval is on the 

basis that the facilities have adequately 

demonstrated that the MPGF are capable 

of achieving or exceeding the emissions 

reductions mandated by the underlying 

NSPS and/or NESHAP. However, 

through a separate effort, we are helping 

to facilitate discussions between the 

communities near these Dow and 

ExxonMobil facilities and the 

companies involved to explore possible 

monitoring that will address specific 

concerns of the communities (see 

‘‘Community Open Forum Discussions’’ 

at Docket ID Number EPA–HQ–OAR– 

2014–0738). 

Comment: A few commenters 

suggested that our provisions should 

allow for at least a 5 percent downtime 

limit for continuous monitoring data 

outside of maintenance periods, 

instrument adjustments and calibration 

checks, similar to the requirements in 

Texas VOC Sampling Rule protocol 

found at 30 TAC 115.725(d)(3). 


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Response: First, we note that the 

Texas VOC sampling protocol only 

excludes time for ‘‘normal calibration 

checks’’ and does not exclude time for 

‘‘maintenance periods’’ or ‘‘instrument 

adjustments.’’ Our initial AMEL notice 

required operation of the continuous 

parameter monitoring system (CPMS) at 

all times except during ‘‘maintenance 

periods, instrument adjustments or 

checks to maintain precision and 

accuracy, calibration checks, and zero 

and span adjustments.’’ Except for the 

time periods we excluded, we consider 

that the monitor should be continuously 

operated. However, we agree with the 

commenters that it is reasonable to set 

an upper limit on the time period for 

maintenance periods and instrument 

adjustments, so we are adding an 

additional sentence to the AMEL 

provisions as follows: ‘‘Additionally, 

maintenance periods, instrument 

adjustments or checks to maintain 

precision and accuracy, and zero and 

span adjustments may not exceed 5 

percent of the time the flare is receiving 

regulated material.’’ 

Comment: One commenter noted that, 

because operating personnel cannot 

enter the fenced area while the MPGF is 

operating, visual observation in 

accordance with the monitoring 

requirements of the General Provisions 

is impractical and cannot assure 

compliance. The commenter also stated 

that visible emissions from ground 

flares are a known problem and that 

community members in Port Arthur 

have submitted several complaints 

about smoke releases from the ground 

flare at the BASF Olefins Plant. 

Therefore, the commenter stated that it 

is imperative for the EPA to assure that 

the AMEL requires video monitoring 

that is adequate to assure compliance. 

Also, the EPA must require each facility 

to submit the video monitoring data to 

the appropriate authorities as part of 

any periodic compliance reports 

required by the CAA. 

Response: We agree that the MPGF 

systems should be operated with no 

visible emissions and we included a 

requirement in the initial AMEL notice 

to use video surveillance cameras to 

demonstrate compliance with this 

requirement. We did not, however, in 

the initial AMEL notice indicate how 

else the operators would demonstrate 

compliance with the visible emissions 

limit. We agree that because operating 

personnel cannot enter the fenced area 

while the MPGF is operating, it is 

difficult to understand how any daily 

EPA Method 22 visible emissions 

monitoring for only 5 minutes during 

the day when operators could enter 

(when the flare was not operating) 

would be an effective method of 

ensuring compliance with this 

requirement. Therefore, we are requiring 

that the MPGF operators employ the use 

of a surveillance camera for visible 

emissions monitoring and record and 

maintain footage of this video for all 

periods when the MPGF is ‘‘operating,’’ 

meaning burning gas other than pilots. 

While we are only requiring the video 

surveillance footage to be maintained as 

a record, we are requiring that Dow and 

ExxonMobil report in their periodic 

compliance reports any deviations of 

the visible emissions standard. 

D. AMEL Mechanism and Process 

Comment: One commenter suggested 

that a successful demonstration of 

equivalent emissions control was 

provided for the proposed MPGF 

burners to be used at both ExxonMobil’s 

Mont Belvieu Plastics Plant and 

Baytown Olefins Plant. In support of 

this suggestion, the commenter suggests 

that the two test reports submitted 

during the comment period, combined 

with the ExxonMobil AMEL 

application, provide the technical 

support and justification to demonstrate 

such equivalency for both of 

ExxonMobil’s plants. 

Response: We agree with the 

commenter that the information 

submitted by ExxonMobil successfully 

demonstrates an equivalent level of 

emissions control for the MPGF burners 

that will be used at ExxonMobil’s Mont 

Belvieu Plastics Plant and Baytown 

Olefins Plant, provided that the 

requirements specified in Section III 

below are met. Therefore, we are 

approving ExxonMobil’s AMEL request 

to use a MPGF at both of its plants. 

Comment: Several commenters 

generally supported the AMEL process 

as an appropriate mechanism to 

authorize use of MPGF as an equivalent 

emissions control technology and also 

provided recommendations for using 

the AMEL process for future projects or 

updates. These recommendations 

included providing flexibility to 

facilities to accommodate burner 

equivalency, providing facilities with a 

simple mechanism that allows 

information or alternate combustion 

parameters to be updated without 

requiring re-approval where additional 

data are provided and providing 

facilities who elect to apply for an 

AMEL a process for providing the EPA 

with information that demonstrates a 

MPGF burner is stable over the expected 

design range in lieu of requiring 

additional emissions (i.e., combustion/

destruction efficiency) testing. 

Response: In light of the comments 

received on providing flexibility for use 

of other, future MPGF burner designs 

and emissions testing, we are providing 

in this notice a framework for sources to 

consider and use to streamline potential 

future approvals of AMEL requests for 

MPGF installations. We note that 

facilities requesting any such alternative 

limit will still have to go through a 

public notice and comment review 

process. 

Comment: A few commenters 

provided additional test information for 

pressure-assisted flares for the EPA to 

consider as having equivalent 

performance to the other burner types 

addressed in the AMEL. Additionally, 

these commenters also suggested that 

flare manufacturers, instead of owners 

or operators of a particular source, be 

allowed to test and pre-certify a 

particular pressure-assisted flare type. 

Response: First, while we appreciate 

the additional pressure-assisted flare 

test data submitted by commenters, 

there is significant detail lacking in the 

submittals to fully evaluate the 

equivalency of these particular flares at 

this time, and, given that some of the 

data submitted are for a flare tip not 

being proposed for use by Dow or 

ExxonMobil, we find that information to 

be outside the scope of the AMEL. With 

respect to allowing flare manufacturers, 

instead of owners or operators of 

sources that would possibly use a MPGF 

to control emissions, to test and precertify a particular type of pressureassisted flare, the CAA sections 

111(h)(3) and 112(h)(3) limit AMEL 

requests to ‘‘the owner or operator of 

any source.’’ Thus, we cannot allow this 

particular request. We are, however, as 

part of this action seeking comment on 

a proposed framework for streamlining 

approval of future AMEL requests for 

MPGF installations which flare 

manufacturers, working in concert with 

the owner or operator of a source who 

wishes to use a pressure-assisted MPGF 

type installation, will be able to follow 

and provide to the agency the necessary 

input, testing and performance 

demonstration information. 

E. Other 

Comment: One commenter stated that 

the AMEL request is based on 

inadequate data to assure 98 percent 

destruction efficiency and stated that 

the EPA must require facilities that seek 

permission to comply with the AMEL in 

lieu of the General Provisions to 

perform long-term passive Fourier 

transform infrared spectroscopy (PFTIR) 

testing to determine the operating limits 

necessary to assure an equivalent level 

of control. The commenter further 

indicated that studies have consistently 

shown that the mixture and specific 


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52432 Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 

chemical composition of the gas 

discharged to a flare impact combustion 

efficiency and that the EPA did not 

verify or investigate whether the 

facilities seeking approval to operate 

under an AMEL will discharge gas to 

the proposed MPGF that is similar in 

chemical composition to the gas used in 

the tests used to develop the AMEL. 

Further, commenters’ review of 

available data suggests that the facilities 

seeking approval to operate under an 

AMEL will discharge gas that exhibit 

hydrogen-olefin interactions. 

Response: As we stated in the initial 

AMEL notice, one general conclusion 

made from the EPA’s 1985 study is that 

stable flare flames and high (>98–99 

percent) combustion and destruction 

efficiencies are attained when flares are 

operated within operating envelopes 

specific to each flare burner and gas 

mixture tested, and that operation 

beyond the edge of the operating 

envelope can result in rapid flame destabilization and a decrease in 

combustion and destruction efficiencies. 

The data where flameout of the burners 

occurred from test runs in both the 

Marathon 2012 test report and the Dow 

2013 test report showed that the flare 

operating envelope was different for the 

different gas mixtures tested. 

Additionally, the data indicate that 

combustion degradation beyond the 

edge of the operating envelope for 

pressure-assisted MPGF burners is so 

rapid that when a flame is present, the 

flare will still achieve a high level of 

combustion efficiency right up until the 

point of flameout. The results of the 

available PFTIR testing demonstrated 

that when a flame was present on the 

pressure-assisted flare burners tested, an 

average combustion efficiency of 99 

percent or greater was achieved. Since 

the initial AMEL notice, we received 

additional combustion efficiency test 

data that further confirms this 

observation (see OCC comments in 

Docket ID Number EPA–HQ–OAR–204– 

0738–0030). In other words, the critical 

parameter in ensuring that the MPGF 

will achieve equivalent efficiency is 

dependent on a stable MPGF burner 

flame rather than the actual combustion 

efficiency, which to date has always 

been 98 percent or better over the gas 

composition mixtures tested. Therefore, 

we do not find that there is a need to 

operate a continuous PFTIR to 

demonstrate continuous combustion 

efficiency for MPGF. Instead, we rely on 

the continuous measurement of net 

heating value or lower flammability 

limit operating limits to ensure that the 

MPGF are operating well above the 

points of flame instability for the gas 

compositions evaluated. Further, based 

on our understanding of the PFTIR 

testing method, it is technically 

impracticable to operate a continuous 

PFTIR due to interferences that would 

be present for a continuous system on 

the multipoint array of burners in the 

MPGF (e.g., availability of multiple sight 

lines and changing ambient conditions 

such as rain or fog). However, in the 

event that technology advancements 

make the continuous demonstration of 

combustion efficiency feasible, we 

acknowledge that this may provide 

another means by which operators can 

demonstrate equivalence with existing 

standards. Finally, while it is true that, 

in the development of operating limits 

for refinery flares, we noted in the 

refinery proposal that a higher NHV cz

target was appropriate for some 

mixtures of olefins and hydrogen, the 

combustion zone operating limits we are 

finalizing in today’s notice are 

significantly more stringent than 

combustion zone parameters developed 

for traditional elevated refinery flares, 

including those with hydrogen and 

olefins, which should alleviate any such 

concerns with respect to combustion 

efficiency for these types of gas 

mixtures. In addition, and as discussed 

elsewhere in this section, an olefinic gas 

mixture (i.e., propylene mixture) was 

tested and used to determine the NHV cz

and LFL cz operating limits for the 

olefins plants applying for an AMEL. 

This gas mixture is both representative 

and challenging to the system with 

respect to the vent gas mixtures the 

MPGF will burn. In fact, when 

considering the full array of flare vent 

gas mixtures tested (e.g., natural gas 

mixtures in the Marathon test, 

propylene mixtures in the Dow test and 

ethylene mixtures in the OCC test) and 

their corresponding points of flare flame 

instability on the MPGF burners, no 

single data point has shown instability 

above the NHV cz (or below the LFL cz) 

operating limits being finalized for Dow 

and ExxonMobil in Section III below. 

Comment: One commenter suggested 

that flare minimization is also another 

important tool to mitigate the impact 

that MPGF will have on communities 

and suggested that the EPA require 

implementation of a flare management 

plan that requires facilities to: 

(1) Identify the sources of the gas 

routed to a flare; 

(2) Assess whether the gas routed to 

a flare can be minimized; 

(3) Describe each flare covered by the 

flare management plan; 

(4) Quantify the baseline flow rate to 

the flare after minimization techniques 

are implemented; 

(5) Establish procedures to minimize 

or eliminate discharges to the flare 

during startup and shutdown 

operations; and 

(6) If the flare is equipped with flare 

gas recovery, establish procedures to 

minimize downtime of the equipment. 

Response: We consider the 

requirement to develop a flare 

management plan to be outside the 

scope of this AMEL. The purpose of this 

AMEL is to set site-specific conditions 

that an operator of a MPGF can use as 

an alternative to the existing 

requirements of 40 CFR 60.18 or 40 CFR 

63.11 for flares, which do not include 

requirements for flare management 

plans. 

III. Final Notice of Approval of the 

AMEL Requests and Required 

Operating Conditions 

Based on information the EPA 

received from Dow and ExxonMobil and 

the comments received through the 

public comment period, operating 

requirements for the pressure-assisted 

MPGF at both of Dow’s plants and both 

of ExxonMobil’s plants that will achieve 

a reduction in emissions at least 

equivalent to the reduction in emissions 

being controlled by a steam-assisted, airassisted or non-assisted flare complying 

with the requirements of either 40 CFR 

63.11(b) or 40 CFR 60.18(b) are as 

follows: 

(1) The MPGF system must be 

designed and operated such that the 

combustion zone gas net heating value 

(NHVcz) is greater than or equal to 800 

Btu/scf or the combustion zone gas 

lower flammability limit (LFLcz) is less 

than or equal to 6.5 percent by volume. 

Owners or operators must demonstrate 

compliance with the NHVcz or LFLcz

metric by continuously complying with 

a 15-minute block average. Owners or 

operators must calculate and monitor 

for the NHVcz or LFLcz according to the 

following: 

(a) Calculation of NHVcz

(i) The owner or operator shall 

determine NHVcz from compositional 

analysis data by using the following 

equation: 


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Where: 

NHVvg = Net heating value of flare vent gas, 

British thermal units per standard cubic 

foot (Btu/scf). Flare vent gas means all gas 

found just prior to the MPGF. This gas 

includes all flare waste gas (i.e., gas from 

facility operations that is directed to a flare 

for the purpose of disposing of the gas), 

flare sweep gas, flare purge gas and flare 

supplemental gas, but does not include 

pilot gas. 

i = Individual component in flare vent gas. 

n = Number of components in flare vent gas. 

xi = Concentration of component i in flare 

vent gas, volume fraction. 

NHVi = Net heating value of component i 

determined as the heat of combustion 

where the net enthalpy per mole of offgas 

is based on combustion at 25 degrees 

Celsius (°C) and 1 atmosphere (or constant 

pressure) with water in the gaseous state 

from values published in the literature, and 

then the values converted to a volumetric 

basis using 20 °C for ‘‘standard 

temperature.’’ Table 1 summarizes 

component properties including net 

heating values. 

(ii) FOR MPGF, NHVvg = NHVcz. 

(b) Calculation of LFLcz

(i) The owner or operator shall 

determine LFLcz from compositional 

analysis data by using the following 

equation: 

Where: 

LFLvg = Lower flammability limit of flare vent 

gas, volume fraction. 

n = Number of components in the vent gas. 

i = Individual component in the vent gas. 

ci = Concentration of component i in the vent 

gas, volume percent (vol %). 

LFLi = Lower flammability limit of 

component i as determined using values 

published by the U.S. Bureau of Mines 

(Zabetakis, 1965), vol %. All inerts, 

including nitrogen, are assumed to have an 

infinite LFL (e.g., LFLN2 = ∞, so that cN2/ 

LFLN2 = 0). LFL values for common flare 

vent gas components are provided in Table 

1. 

(ii) FOR MPGF, LFLvg = LFLcz. 

(c) The operator of a MPGF system 

shall install, operate, calibrate and 

maintain a monitoring system capable of 

continuously measuring flare vent gas 

flow rate. 

(d) The operator shall install, operate, 

calibrate and maintain a monitoring 

system capable of continuously 

measuring (i.e., at least once every 15- 

minutes), calculating, and recording the 

individual component concentrations 

present in the flare vent gas or the 

owner or operator shall install, operate, 

calibrate and maintain a monitoring 

system capable of continuously 

measuring, calculating and recording 

NHVvg.

(e) For each measurement produced 

by the monitoring system, the operator 

shall determine the 15-minute block 

average as the arithmetic average of all 

measurements made by the monitoring 

system within the 15-minute period. 

(f) The operator must follow the 

calibration and maintenance procedures 

according to Table 2. Maintenance 

periods, instrument adjustments or 

checks to maintain precision and 

accuracy and zero and span adjustments 

may not exceed 5 percent of the time the 

flare is receiving regulated material. 

TABLE 1—INDIVIDUAL COMPONENT PROPERTIES

Component Molecular formula 

MW i

(pounds per 

pound-mole) 

NHVi

(British thermal 

units per standard 

cubic foot) 

LFL i

(volume %) 

Acetylene ............................................................ C2H2 .......................................... 26.04 1,404 2.5 

Benzene .............................................................. C6H6 .......................................... 78.11 3,591 1.3 

1,2-Butadiene ..................................................... C4H6 .......................................... 54.09 2,794 2.0 

1,3-Butadiene ..................................................... C4H6 .......................................... 54.09 2,690 2.0 

iso-Butane ........................................................... C4H10 ........................................ 58.12 2,957 1.8 

n-Butane ............................................................. C4H10 ........................................ 58.12 2,968 1.8 

cis-Butene ........................................................... C4H8 .......................................... 56.11 2,830 1.6 

iso-Butene ........................................................... C4H8 .......................................... 56.11 2,928 1.8 

trans-Butene ....................................................... C4H8 .......................................... 56.11 2,826 1.7 

Carbon Dioxide ................................................... CO2 ........................................... 44.01 0 ∞ 

Carbon Monoxide ............................................... CO ............................................ 28.01 316 12.5 

Cyclopropane ...................................................... C3H6 .......................................... 42.08 2,185 2.4 

Ethane ................................................................ C2H6 .......................................... 30.07 1,595 3.0 

Ethylene .............................................................. C2H4 .......................................... 28.05 1,477 2.7 

Hydrogen ............................................................ H2 .............................................. 2.02 274 4.0 

Hydrogen Sulfide ................................................ H2S ........................................... 34.08 587 4.0 

Methane .............................................................. CH4 ........................................... 16.04 896 5.0 

Methyl-Acetylene ................................................ C3H4 .......................................... 40.06 2,088 1.7 

Nitrogen .............................................................. N2 .............................................. 28.01 0 ∞ 

Oxygen ............................................................... O2 .............................................. 32.00 0 ∞ 

Pentane+ (C5+) .................................................. C5H12 ........................................ 72.15 3,655 1.4 

Propadiene ......................................................... C3H4 .......................................... 40.06 2,066 2.16 


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TABLE 1—INDIVIDUAL COMPONENT PROPERTIES—Continued 

Component Molecular formula 

MW i

(pounds per 

pound-mole) 

NHVi

(British thermal 

units per standard 

cubic foot) 

LFL i

(volume %) 

Propane .............................................................. C3H8 .......................................... 44.10 2,281 2.1 

Propylene ............................................................ C3H6 .......................................... 42.08 2,150 2.4 

Water .................................................................. H2O ........................................... 18.02 0 ∞ 

TABLE 2—ACCURACY AND CALIBRATION REQUIREMENTS

Parameter Accuracy requirements Calibration requirements 

Flare Vent Gas Flow Rate ... ±20 percent of flow rate at 

velocities ranging from 

0.1 to 1 feet per second.

±5 percent of flow rate at 

velocities greater than 1 

foot per second.

Performance evaluation biennially (every two years) and following any period of 

more than 24 hours throughout which the flow rate exceeded the maximum rated 

flow rate of the sensor, or the data recorder was off scale. Checks of all mechanical connections for leakage monthly. Visual inspections and checks of system 

operation every 3 months, unless the system has a redundant flow sensor. 

Select a representative measurement location where swirling flow or abnormal velocity distributions due to upstream and downstream disturbances at the point of 

measurement are minimized. 

Pressure ............................... ±5 percent over the normal 

range measured or 0.12 

kilopascals (0.5 inches of 

water column), whichever 

is greater.

Review pressure sensor readings at least once a week for straight-line (unchanging) pressure and perform corrective action to ensure proper pressure sensor operation if blockage is indicated. 

Performance evaluation annually and following any period of more than 24 hours 

throughout which the pressure exceeded the maximum rated pressure of the 

sensor, or the data recorder was off scale. Checks of all mechanical connections 

for leakage monthly. Visual inspection of all components for integrity, oxidation 

and galvanic corrosion every 3 months, unless the system has a redundant pressure sensor. 

Select a representative measurement location that minimizes or eliminates pulsating pressure, vibration, and internal and external corrosion. 

Net Heating Value by Calorimeter.±2 percent of span ............. Calibration requirements should follow manufacturer’s recommendations at a minimum. 

Temperature control (heated and/or cooled as necessary) the sampling system to 

ensure proper year-round operation. 

Where feasible, select a sampling location at least two equivalent diameters downstream from and 0.5 equivalent diameters upstream from the nearest disturbance. Select the sampling location at least two equivalent duct diameters from 

the nearest control device, point of pollutant generation, air in-leakages, or other 

point at which a change in the pollutant concentration or emission rate occurs. 

Net Heating Value by Gas 

Chromatograph.

As specified in Performance Specification 9 of 

40 CFR part 60, Appendix B.

Follow the procedure in Performance Specification 9 of 40 CFR part 60, Appendix 

B, except that a single daily mid-level calibration check can be used (rather than 

triplicate analysis), the multi-point calibration can be conducted quarterly (rather 

than monthly), and the sampling line temperature must be maintained at a minimum temperature of 60 °C (rather than 120 °C). 

(2) The MPGF system shall be 

operated with a flame present at all 

times when in use. Each stage of MPGF 

burners must have at least two pilots 

with a continuously lit pilot flame. The 

pilot flame(s) must be continuously 

monitored by a thermocouple or any 

other equivalent device used to detect 

the presence of a flame. The time, date 

and duration of any complete loss of 

pilot flame on any stage of MPGF 

burners must be recorded. Each 

monitoring device must be maintained 

or replaced at a frequency in accordance 

with the manufacturer’s specifications. 

(3) The MPGF system shall be 

operated with no visible emissions 

except for periods not to exceed a total 

of 5 minutes during any 2 consecutive 

hours. A video camera that is capable of 

continuously recording (i.e., at least one 

frame every 15 seconds with time and 

date stamps) images of the flare flame 

and a reasonable distance above the 

flare flame at an angle suitable for 

visible emissions observations must be 

used to demonstrate compliance with 

this requirement. The owner or operator 

must provide real-time video 

surveillance camera output to the 

control room or other continuously 

manned location where the video 

camera images may be viewed at any 

time. 

(4) The operator of a MPGF system 

shall install and operate pressure 

monitor(s) on the main flare header, as 

well as a valve position indicator 

monitoring system for each staging 

valve to ensure that the MPGF operates 

within the range of tested conditions or 

within the range of the manufacturer’s 

specifications. The pressure monitor 

shall meet the requirements in Table 2. 

Maintenance periods, instrument 

adjustments or checks to maintain 

precision and accuracy, and zero and 

span adjustments may not exceed 5 

percent of the time the flare is receiving 

regulated material. 

(5) Recordkeeping Requirements 

(a) All data must be recorded and 

maintained for a minimum of three 

years or for as long as applicable rule 

subpart(s) specify flare records should 

be kept, whichever is more stringent. 

(6) Reporting Requirements 

(a) The information specified in (b) 

and (c) below should be reported in the 

timeline specified by the applicable rule 

subpart(s) for which the MPGF will 

control emissions. 

(b) Owners or operators should 

include the following information in 

their initial Notification of Compliance 

status report: 


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Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 52435 

(i) Specify flare design as a pressureassisted MPGF. 

(ii) All visible emission readings, 

NHVcz and/or LFLcz determinations and 

flow rate measurements. For MPGF, exit 

velocity determinations do not need to 

be reported as the maximum permitted 

velocity requirements in the General 

Provisions at 40 CFR 60.18 and 40 CFR 

63.11 are not applicable. 

(iii) All periods during the 

compliance determination when a 

complete loss of pilot flame on any stage 

of MPGF burners occurs. 

(iv) All periods during the compliance 

determination when the pressure 

monitor(s) on the main flare header 

show the MPGF burners operating 

outside the range of tested conditions or 

outside the range of the manufacturer’s 

specifications. 

(v) All periods during the compliance 

determination when the staging valve 

position indicator monitoring system 

indicates a stage of the MPGF should 

not be in operation and is or when a 

stage of the MPGF should be in 

operation and is not. 

(c) The owner or operator shall notify 

the Administrator of periods of excess 

emissions in their Periodic Reports. 

These periods of excess emissions shall 

include: 

(i) Records of each 15-minute block 

during which there was at least one 

minute when regulated material was 

routed to the MPGF and a complete loss 

of pilot flame on a stage of burners 

occurred. 

(ii) Records of visible emissions 

events that are time and date stamped 

and exceed more than 5 minutes in any 

2 hour consecutive period. 

(iii) Records of each 15-minute block 

period for which an applicable 

combustion zone operating limit (i.e., 

NHVcz or LFLcz) is not met for the MPGF 

when regulated material is being 

combusted in the flare. Indicate the date 

and time for each period, the NHVcz

and/or LFLcz operating parameter for the 

period and the type of monitoring 

system used to determine compliance 

with the operating parameters (e.g., gas 

chromatograph or calorimeter). 

(iv) Records of when the pressure 

monitor(s) on the main flare header 

show the MPGF burners are operating 

outside the range of tested conditions or 

outside the range of the manufacturer’s 

specifications. Indicate the date and 

time for each period, the pressure 

measurement, the stage(s) and number 

of MPGF burners affected and the range 

of tested conditions or manufacturer’s 

specifications. 

(v) Records of when the staging valve 

position indicator monitoring system 

indicates a stage of the MPGF should 

not be in operation and is or when a 

stage of the MPGF should be in 

operation and is not. Indicate the date 

and time for each period, whether the 

stage was supposed to be open but was 

closed or vice versa and the stage(s) and 

number of MPGF burners affected. 

IV. Notice of AMEL Request for 

Occidental Chemical Corporation 

On December 16, 2014, OCC 

submitted an AMEL request indicating 

plans to construct an ethylene 

production unit that will be comprised 

of five ethane cracking furnaces and 

associated recovery equipment at its 

plant located in Ingleside, Texas. As 

part of this request, OCC described 

plans to control emissions from the 

ethylene production unit using two 

thermal oxidizers as both a primary and 

backup control device for periods of 

normal operation and low-pressure 

maintenance, startup, and shutdown 

events, and that it is seeking an AMEL 

for a MPGF installation for use during 

limited high-pressure maintenance, 

startup, and shutdown events as well 

emergency situations. As part of its 

AMEL request, as well as in its 

comments submitted to Docket ID 

Number EPA–HQ–OAR–2014–0738– 

0030 on March 30, 2015, during the 

Dow and ExxonMobil initial AMEL 

notice comment period, OCC requested 

an AMEL for use of different MPGF 

burners at its plant located in Ingleside, 

Texas, than the burners Dow and 

ExxonMobil plan to use at their plants. 

Specifically, OCC provided both 

destruction efficiency/combustion 

efficiency testing and long-term MPGF 

flame stability testing for ethylene and 

ethylene-inert waste gas mixtures on its 

proposed MPGF burners. These test data 

show good performance below an NHVcz

of 800 Btu/scf or above an LFLcz of 6.5 

volume percent, although OCC stated in 

the AMEL request that it plans to 

comply with the same compliance 

requirements laid out for Dow and 

ExxonMobil in Section III above. 

Therefore, we are seeking comment on 

whether these operating requirements 

would establish an AMEL for OCC that 

will achieve a reduction in emissions at 

least equivalent to the reduction in 

emissions for flares complying with the 

requirements in 40 CFR 63.11(b) or 40 

CFR 60.18(b). 

V. Notice of Framework for 

Streamlining Approval of Future 

Pressure-Assisted MPGF AMEL 

Requests 

We are seeking comments on a 

framework sources may use to submit 

an AMEL request to the EPA to use 

MPGF as control devices to comply with 

NSPS and NESHAP under 40 CFR parts 

60, 61, and 63. At a minimum, sources 

considering use of MPGF as an 

emissions control technology should 

provide the EPA with the following 

information in its AMEL request when 

demonstrating MPGF equivalency: 

(1) Project Scope and Background 

(a) Size and scope of plant, products 

produced, location of facility and the 

MPGF proximity, if less than 2 miles, to 

the local community and schools. 

(b) Details of overall emissions control 

scheme (e.g., low pressure control 

scenario and high pressure control 

scenario), MPGF capacity and operation 

(including number of rows (stages), 

number of burners and pilots per stage 

and staging curve), and MPGF control 

utilization (e.g., handles routine flows, 

only flows during periods of startup, 

shutdown, maintenance, emergencies). 

(c) Details of typical and/or 

anticipated flare waste gas compositions 

and profiles for which the MPGF will 

control. 

(d) MPGF burner design including 

type, geometry, and size. 

(e) Anticipated date of startup. 

(2) Regulatory Applicability 

(a) Detailed list or table of applicable 

regulatory subparts, applicable 

standards that allow use of flares, and 

authority that allows for use of an 

AMEL. 

(3) Destruction Efficiency/Combustion 

Efficiency Performance Demonstration 

(a) Sources must provide a 

performance demonstration to the 

agency that the MPGF pressure-assisted 

burner being proposed for use will 

achieve a level of control at least 

equivalent to the most stringent level of 

control required by the underlying 

standards (e.g., 98% destruction 

efficiency or better). Facilities can elect 

to do a performance test that includes a 

minimum of three test runs under the 

most challenging conditions (e.g., 

highest operating pressure and/or sonic 

velocity conditions) using PFTIR 

testing, extractive sampling or rely on 

an engineering assessment. Sources 

must test using fuel representative of the 

type of waste gas the MPGF will 

typically burn or substitute a waste gas 

such as an olefin gas or olefinic gas 

mixture that will challenge the MPGF to 

perform at a high level of control in a 

smokeless capacity. 

(i) If a performance test is done, a test 

report must be submitted to the agency 

which includes at a minimum: A 

description of the testing, a protocol 

describing the test methodology used, 

associated test method quality 

assurance/quality control (QA/QC) 

parameters, raw field and laboratory 

data sheets, summary data report sheets, 


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52436 Federal Register / Vol. 80, No. 168 / Monday, August 31, 2015 / Proposed Rules 

calibration standards, calibration 

curves, completed visible emissions 

observation forms, a calculation of the 

average destruction efficiency and 

combustion efficiency over the course of 

each test, the date, time and duration of 

the test, the waste gas composition and 

NHVcz and/or LFLcz the gas tested, the 

flowrate (at standard conditions) and 

velocity of the waste gas, the MPGF 

burner tip pressure, waste gas 

temperature, meteorological conditions 

(e.g., ambient temperature, and 

barometric pressure, wind speed and 

direction, relative humidity), and 

whether there were any observed flare 

flameouts. 

(ii) If an engineering assessment is 

done, sources must provide to the 

agency a demonstration that a proper 

level of destruction/combustion 

efficiency was obtained, through prior 

performance testing or the like for a 

similar equivalent burner type design. 

To support an equivalent burner 

assessment of destruction/combustion 

efficiency, sources must discuss and 

provide information related to design 

principles of burner type, burner size, 

burner geometry, air-fuel mixing, and 

the combustion principles associated 

with this burner that will assure 

smokeless operation under a variety of 

operating conditions. Similarly, sources 

must also provide details outlining why 

all of these factors, in concert with the 

waste gas that was tested in the 

supporting reference materials, support 

the conclusion that the MPGF burners 

being proposed for use by the source 

will achieve at least an equivalent level 

of destruction efficiency as required by 

the underlying applicable regulations. 

(4) Long-Term MPGF Stability Testing 

(a) The operation of a MPGF with a 

stable, lit flame is of paramount 

importance to continuously ensuring 

good flare performance; therefore, any 

source wishing to demonstrate 

equivalency for purposes of using these 

types of installations must conduct a 

long-term stability performance test. 

Since flare tip design and waste gas 

composition have significant impact on 

the range of stable operation, sources 

should use a representative waste gas 

the MPGF will typically burn or a waste 

gas, such as an olefin or olefinic 

mixture, that will challenge the MPGF 

to perform at a high level with a stable 

flame as well as challenge its smokeless 

capacity. 

(b) Sources should first design and 

carry out a performance test to 

determine the point of flare flame 

instability and flameout for the MPGF 

burner and waste gas composition 

chosen to be tested. Successful, initial 

demonstration of stability is achieved 

when there is a stable, lit flame for a 

minimum of five minutes at consistent 

flow and waste gas composition. It is 

recommended, although not required, 

that sources determine the point of 

instability at sonic flow conditions or at 

the highest operating pressure 

anticipated. Any data which 

demonstrates instability and complete 

loss of flame prior to the five minute 

period must be reported along the initial 

stable flame demonstration. Along with 

destruction efficiency and combustion 

efficiency, the data elements laid out in 

3(a)(i) should also be reported. 

(c) Using the results from (b) above as 

a starting point, sources must perform a 

minimum of three replicate tests at both 

the minimum and maximum operating 

conditions on at least one MPGF burner 

at or above the NHVcz or at or below the 

LFL cz determined in 4(b). If more than 

one burner is tested, the spacing 

between the burners must be 

representative of the projected 

installation. Each test must be a 

minimum of 15-minutes in duration 

with constant flow and composition for 

the three runs at minimum conditions, 

and the three runs at the maximum 

conditions. The data and data elements 

mentioned in 4(b) must also be reported. 

(5) MPGF Cross-light Testing 

(a) Sources must design and carryout 

a performance test to successfully 

demonstrate that cross-lighting of the 

MPGF burners will occur over the range 

of operating conditions (e.g., operating 

pressure and/or velocity (Mach) 

condition) for which the burners will be 

used. Sources may use the NHVcz and/ 

or LFLcz established in 4 above and 

perform a minimum of three replicate 

runs at each of the operating conditions. 

Sources must cross-light a minimum of 

three burners and the spacing between 

the burners and location of the pilot 

flame must be representative of the 

projected installation. At a minimum, 

sources must report the following: A 

description of the testing, a protocol 

describing the test methodology used, 

associated test method QA/QC 

parameters, the waste gas composition 

and NHVcz and/or LFLcz of the gas 

tested, the velocity (or Mach speed 

ratio) of the waste gas tested, the MPGF 

burner tip pressure, the time, length, 

and duration of the test, records of 

whether a successful cross-light was 

observed over all of the burners and the 

length of time it took for the burners to 

cross-light, records of maintaining a 

stable flame after a successful cross-light 

and the duration for which this was 

observed, records of any smoking events 

during the cross-light, waste gas 

temperature, meteorological conditions 

(e.g., ambient temperature, and 

barometric pressure, wind speed and 

direction, relative humidity), and 

whether there were any observed flare 

flameouts. 

(6) Flaring Reduction Considerations 

(a) Sources must make a 

demonstration, considering MPGF 

utilization, on whether additional flare 

reduction measures, including flare gas 

recovery, should be utilized and 

implemented. 

(7) MPGF Monitoring and Operating 

Conditions 

(a) Based on the results of the criteria 

mentioned above in this section, sources 

must make recommendations to the 

agency on the type of monitoring and 

operating conditions necessary for the 

MPGF to demonstrate equivalent 

reductions in emissions as compared to 

flares complying with the requirements 

at 40 CFR 60.18 and 40 CFR 63.11, 

taking into consideration a control 

scheme designed to handle highly 

variable flows and waste gas 

compositions. 

We solicit comment on all aspects of 

this framework. We anticipate this 

framework would enable the agency to 

review and approve future AMEL 

requests for MPGF installations in a 

more expeditious timeframe because we 

anticipate that the information required 

by the framework would provide us 

with sufficient information to evaluate 

future AMEL requests. We note that all 

aspects of future AMEL requests would 

still be subject to a notice and comment 

proceeding. 

Dated: August 20, 2015. 

Janet G. McCabe, 

Acting Assistant Administrator. 

[FR Doc. 2015–21420 Filed 8–28–15; 8:45 am] 

BILLING CODE 6560–50–P 

DEPARTMENT OF HOMELAND 

SECURITY 

Federal Emergency Management 

Agency 

44 CFR Part 67 

[Docket ID FEMA–2015–0001; Internal 

Agency Docket No. FEMA–B–1149] 

Proposed Flood Elevation 

Determinations for Jackson County, 

Arkansas, and Incorporated Areas 

AGENCY: Federal Emergency 

Management Agency, DHS. 

ACTION: Proposed rule; withdrawal. 

SUMMARY: The Federal Emergency 

Management Agency (FEMA) is 

withdrawing its proposed rule 

concerning proposed flood elevation 


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