
[Federal Register Volume 81, Number 77 (Thursday, April 21, 2016)]
[Notices]
[Pages 23480-23488]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-08911]


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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OAR-2014-0738; FRL-9945-15-OAR]


Notice of Final Approval for the Operation of a Pressure-Assisted 
Multi-Point Ground Flare at Occidental Chemical Corporation

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice; final approval.

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SUMMARY: This notice announces our approval of the Alternative Means of 
Emission Limitation (AMEL) request for the operation of a multi-point 
ground flare (MPGF) at Occidental Chemical Corporation's (OCC) ethylene 
plant in Ingleside, Texas. This approval notice specifies the operating 
conditions and monitoring, recordkeeping, and reporting requirements 
for demonstrating compliance with the AMEL request that this facility 
must follow. In addition, this notice finalizes a framework that 
facilities can follow to help expedite and streamline approval of 
future AMEL requests for pressure-assisted MPGF.

DATES: The AMEL request for the MPGF at OCC's ethylene plant in 
Ingleside, Texas, is approved and in effect on April 21, 2016.

ADDRESSES: The Environmental Protection Agency (EPA) has established a 
docket for this action under Docket ID No. EPA-HQ-OAR-2014-0738. All 
documents in the docket are listed on the http://www.regulations.gov 
Web site. Although listed in the index, some information is not 
publicly available, e.g., confidential business information (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 form. 
Publicly available docket materials are available either electronically 
through http://www.regulations.gov, or in hard copy at the EPA Docket 
Center, EPA WJC West Building, Room Number 3334, 1301 Constitution Ave. 
NW., Washington, DC. The Public Reading Room hours of operation are 
8:30 a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through 
Friday. The telephone number for the Public Reading Room is (202) 566-
1744, and the telephone number for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For questions about this final 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 foot
CBI confidential business information
CFR Code of Federal Regulations
EPA Environmental Protection Agency
Eqn equation
FR Federal Register
GC gas chromatograph
HAP hazardous air pollutants
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
PS Performance Specification
QA quality assurance
QC quality control
VOC volatile organic compounds

    Organization of This Document. The information in this notice is 
organized as follows:

I. Background
    A. Summary
    B. Regulatory Flare Requirements and OCC's AMEL Request
II. Summary of Public Comments on OCC's AMEL Request and the 
Framework for Streamlining Approval of Future Pressure-Assisted MPGF 
AMEL Requests
    A. OCC's AMEL Request
    B. Framework for Streamlining Approval of Future Pressure-
Assisted MPGF AMEL Requests
III. Final Notice of Approval of OCC's AMEL Request and Required 
Operating Conditions
IV. Final Framework for Streamlining Approval of Future Pressure-
Assisted MPGF AMEL Requests

I. Background

A. Summary

    On August 31, 2015, the EPA published an initial notification in 
the Federal Register (FR) acknowledging receipt of an AMEL approval 
request for the operation of an MPGF at OCC's ethylene plant in 
Ingleside, Texas, (see 80 FR 52426, August 31, 2015). This initial 
notification solicited comment on all aspects of the AMEL request 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

[[Page 23481]]

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, OCC 
requested an AMEL. This action provides a summary of the comments 
received as part of the public review process, our responses to those 
comments, and our approval of the AMEL request received from OCC for 
use of a pressure-assisted MPGF at their Ingleside, Texas, ethylene 
plant, along with the operating conditions they must follow for 
demonstrating compliance with the AMEL request.
    Additionally, the August 31, 2015, FR initial notification also 
solicited comment on 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. This action provides a summary of 
comments received on the framework as part of the public review 
process, our responses to those comments, and finalizes a framework for 
streamlining future pressure-assisted MPGF AMEL requests. We note that 
future AMEL requests would still require a notice and an opportunity 
for the public to comment.

B. Regulatory Flare Requirements and OCC's AMEL Request

    OCC submitted an AMEL request to the EPA on December 16, 2014, 
seeking to operate an MPGF for use during limited high-pressure 
maintenance, startup, and shutdown events, as well as emergency 
situations at their ethylene plant in Ingleside, Texas. In their 
request, OCC cited various regulatory requirements in 40 CFR parts 60, 
61, and 63 that will apply to the flare waste gas streams that will be 
collected and routed to their pressure-assisted MPGF. OCC sought such 
an AMEL request because their MPGF is not designed to operate below the 
maximum permitted velocity requirements for flares in the General 
Provisions of 40 CFR parts 60 and 63. OCC provided information that the 
MPGF they propose to use will achieve a reduction in emissions at least 
equivalent to the reduction in emissions for flares complying with 
these General Provisions requirements (for further background 
information on the regulatory flare requirements and a facility's 
ability to request an AMEL, see 80 FR 52427-52428, August 31, 2015).

II. Summary of Public Comments on OCC's AMEL Request and the Framework 
for Streamlining Approval of Future Pressure-Assisted MPGF AMEL 
Requests

    This section contains a summary of 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). This section also contains a summary of the major 
comments and responses received on the framework for streamlining 
approval of future MPGF AMEL requests and our rationale for finalizing 
this framework.

A. OCC's AMEL Request

    Comment: Commenters stated that the LFLcz equation (i.e., Eqn. 2 in 
Section III below) should be revised so that the calculated LFLvg is 
expressed in volume percent rather than in volume fraction.
    Response: While the equation is mathematically correct with respect 
to calculating LFLvg in volume fraction, we agree with the commenters 
that it should be revised to reflect the same units as the compliance 
metric of LFLvg in volume percent. Since multiplying the volume 
fraction term by 100 will yield a result in units of volume percent, we 
have updated Eqn. 2 in Section III to reflect this consistency change.
    Comment: Commenters stated that the calibration requirements in 
Table 2 of Section III of this notice require OCC to monitor net 
heating value by gas chromatograph (GC) and follow the procedure in 
Performance Specification (PS) 9 of 40 CFR part 60, appendix B, and 
that these requirements require a daily mid-level calibration check and 
that the EPA should change them from a daily basis to a weekly basis. 
Commenters stated that a weekly calibration should be allowed because 
operating conditions in Table 2 in Section III(1)(f) of this notice 
only allow the time needed to perform a daily calibration, along with 
other maintenance periods and instrument adjustments, to not exceed 5 
percent and that a daily calibration will lead to a built-in loss of 
monitor downtime of almost 5 percent since it requires 1 hour in a 24-
hour day (e.g., 4.2 percent of the time). Commenters also requested 
that this monitor downtime should be calculated on a rolling 12-month 
basis for compliance purposes and that the EPA clarify that the 
calibration and maintenance procedures conducted when the flare is not 
receiving regulated material be excluded from the monitor downtime 
calculation.
    Response: The requirement to perform a daily mid-level calibration 
check for a GC is codified in the procedure of PS 9 of 40 CFR part 60, 
appendix B, and Table 2 of Section III in this notice already provides 
some relief with respect to the amount of analysis needed (i.e., a 
single daily mid-level calibration check can be used (rather than 
triplicate analysis)) for the calibration checks on a GC. The AMEL does 
not require monitoring with a GC, but rather allows for the use of 
either a GC or a calorimeter to demonstrate compliance with the 
monitoring and operating requirements. Given that OCC's MPGF will 
handle both planned maintenance, startup and shutdown events as well as 
potential emergency situations, a monitoring system used to demonstrate 
compliance for this AMEL must be capable of producing a reliable result 
instantaneously, and the more frequent (i.e., daily) calibrations 
required in PS 9 provides a high level of assurance that the GC reading 
will be both precise and accurate. Thus, we are not changing the 
requirement within PS 9 to allow less frequent (i.e., weekly) 
calibration checks for a GC. We do understand that monitoring equipment 
can break down or need maintenance from time to time to continue to 
perform reliably. Therefore, to provide flexibility that ensures the GC 
is maintained properly, we are clarifying that calibration and 
maintenance procedures conducted when the flare is not receiving 
regulated material are excluded from the monitor downtime calculation. 
Also, we are clarifying that monitor downtime to perform calibration 
and maintenance procedures may not exceed 5 percent of the time when 
the flare is receiving regulated material, calculated on an annual, 
non-rolling average basis as OCC further clarified in their comments on 
the AMEL request during a conference call with the EPA (see memorandum, 
``Meeting Record for January 12, 2016, Meeting Between the U.S. EPA and 
Occidental Chemical Corporation,'' at Docket ID No. EPA-HQ-OAR-2014-
0738).
    Comment: Commenters stated that the EPA should include a provision 
in the final AMEL to allow a small percentage of downtime (i.e., 5 
percent of the time the flare is receiving regulated material) for 
video camera maintenance and repair/replacement. One commenter asked 
for the EPA to add language to

[[Page 23482]]

clarify that the video camera requirement for monitoring visible 
emissions applies only when the flare is receiving regulated material.
    Response: Given that the MPGFs approved in earlier AMELs, as well 
as OCC's MPGF, are all back-up control devices, we are clarifying that 
the video camera requirement for monitoring visible emissions applies 
only when the flare is receiving regulated material. Furthermore, while 
we realize that MPGFs have sufficiently tall fences built around them 
primarily for safety, their design does pose a potential challenge with 
respect to allowing a person on the ground to monitor the MPGFs for 
visible emissions. Given that the AMEL requests we have approved to 
date from The Dow Chemical Company (Dow) and ExxonMobil Chemical 
Company (ExxonMobil) (see 80 FR 52426, August 31, 2015), as well as 
this AMEL approved for OCC, all allow for permitted use of MPGF only in 
cases of maintenance, startup, shutdown, and emergency situations and 
not on a continuous basis, the time when the MPGF is not in operation 
should be sufficient for video camera maintenance and repair/
replacement to occur. Therefore, we are not including a provision to 
allow any downtime for video camera maintenance and repair/replacement 
when the MPGF is receiving regulated material.
    Comment: A few commenters suggested that the EPA clarify the 
language in the referenced operating conditions in Section III(2) of 
this notice which states: ``Each stage of MPGF burners must have at 
least two pilots with a continuously lit pilot flame.'' Specifically, 
commenters requested that the EPA clarify that while each stage of the 
MPGF is equipped with a minimum of two pilots, that only one 
continuously lit pilot flame is needed when the stage is in operation.
    Response: We disagree that it is necessary to change the operating 
conditions language in Section III(2) as suggested by the commenters, 
and we believe the requirements for the OCC AMEL approval should be 
consistent with the previous AMEL operating conditions published for 
both Dow and ExxonMobil (see 80 FR 52426, August 31, 2015). The 
operating conditions in Section III(2) and reporting requirements in 
Section III(6) of this notice are clear that the MPGF system should be 
equipped with a minimum of two pilots per stage and that a flame must 
be present at all times the stage is in use and burning regulated 
material. In addition, a complete loss of pilot flame for more than 1 
minute in a 15-minute period is an excess emission that must be 
reported.
    Comment: One commenter requested that the EPA clarify the language 
with respect to requiring ``records'' in the excess emissions reporting 
requirements and suggested replacing the term with ``periods.''
    Response: We disagree with changing the terminology ``records'' to 
``periods'' in the excess emissions reporting requirements. Section 
III(6)(c) of the operating conditions below are clear that we are not 
requiring reporting of all records that an owner or operator may keep 
or that they may be required to keep as a condition of AMEL approval 
for a given MPGF, but rather, that the owner or operator must report 
the specific information in the excess emissions report.

B. Framework for Streamlining Approval of Future Pressure-Assisted MPGF 
AMEL Requests

    Comment: One commenter stated that the framework for streamlining 
approval of future MPGF AMEL requests should not require information 
unrelated to a burner equivalency determination, information that has 
already been submitted to other parts of the Agency for permitting 
purposes, or proprietary MPGF burner design information. Specifically, 
the commenter stated that the EPA should remove the following 
information from the framework that owners or operators seeking 
approval of an MPGF AMEL are required to submit:
     Details of the overall emissions control scheme: Section 
IV(1)(b).
     MPGF capacity and operation (including number of rows 
(stages), number of burners and pilots per stage and staging curve): 
Section IV(1)(b).
     MPGF burner size and design: Section IV(1)(c) and (1)(d).
     Cross-light testing: Section IV(5) in its entirety.
     Flaring reduction considerations: Section IV(6)(a).
    Another commenter stated that at Section IV(3)(a)(ii), for an 
engineering evaluation demonstration, once a burner of a specific type, 
size, and geometry has been tested on a waste gas, that burner can be 
considered to be proven stable and smokeless for that waste gas only. 
Further, the commenter states that engineering assessment and 
extrapolation should only be permitted under the framework where burner 
design and waste gas are the same as tested because any deviation in 
burner design or waste gas could lead to significant changes in 
stability or smokeless capacity.
    Response: First, we note that the objective of the framework is to 
provide the regulated community with a clear and concise understanding 
of the minimum information that must be provided to the Agency so that 
we can adequately evaluate an MPGF AMEL request. The information listed 
in the framework is necessary to evaluate whether an MPGF operates 
properly and controls emissions of regulated material at least 
equivalent to applicable regulations. Hence, information related to 
details of the overall emissions control scheme, MPGF capacity, 
operation and burner size, cross-light testing, and flaring reduction 
considerations are all important and necessary information to 
adequately make an equivalency determination. Therefore, we are not 
removing them from the framework.
    Second, with respect to submitting information that may have been 
developed and submitted already for permitting purposes, we note that 
this framework is designed to help streamline and expedite future 
approvals of MPGF AMEL requests. If an owner or operator does not 
submit the information set forth in the framework, additional time and 
resources will have to be spent to evaluate the AMEL request.
    Lastly, with respect to concerns about MPGF burner design and the 
potential for some of the information to be proprietary (e.g., 
geometry, tip drillings, and hole size), we note that the MPGF burner 
tests conducted to date indicate that flare head design (along with 
waste gas composition) can influence flame stability, which is one of 
the more important factors affecting performance of the MPGF that the 
Agency must consider in whether to approve an AMEL request and agree 
with the commenter that flare stability is affected by burner design/
waste gas combination tested (see 80 FR 8023, February 13, 2015, for 
more details). To the extent the owner, operator or flare vendor/
manufacturer considers this information to be CBI, they should note 
that in their MPGF AMEL request, and we will provide details on our CBI 
policy and procedures on how they should submit this information to the 
Agency after the AMEL request has been received. At a minimum, 
facilities should note the flare vendor and burner model name.
    Comment: One commenter recommended that the framework allow flare 
vendors/manufacturers and owners or operators to determine and document 
the most appropriate burner testing durations (e.g., 5-minute screening 
test to determine flameout followed by three 15-minute tests at other 
more stable points). Another commenter suggested that for the sole 
purpose of flame

[[Page 23483]]

stability evaluation, 3 to 5 minutes is sufficient for a testing 
duration.
    One commenter suggested that the specific requirements of the flare 
flame stability tests be enumerated in Section IV(4)(b) below since it 
references back to performance test information in Section IV(3)(a)(i).
    Response: After consideration of the comments received during the 
comment period as well as the supplemental technical information 
received after the close of the comment period (see memorandum, 
``Meeting Record for January 7, 2016, Meeting Between the U.S. EPA and 
Zeeco,'' at Docket ID No. EPA-HQ-OAR-2014-0738), we agree with the 
commenters that the duration of the MPGF stability test runs in Section 
IV(4)(c) can be shortened from 15 minutes, but disagree with the 
commenters that we should allow flare vendors/manufacturers and owners 
or operators to determine and document the most appropriate burner 
testing durations. In reviewing the available test data on an MPGF 
where unstable test runs with constant conditions were observed, a few 
runs were aborted in 4 minutes or less due to instability (see 
memorandum, ``Review of Available Test Data on Multipoint Ground 
Flares,'' at Docket ID No. EPA-HQ-OAR-2014-0738-0002). The commenters 
have suggested that the instability was related to the changing and 
decreasing heat content and composition of the fuel gas stream as the 
fuel gas mixture was being produced for the trial flare run. If the 
demonstration had instead relied upon a constant gas mixture that could 
have been produced in a mix tank, rather than an online mixer, than the 
demonstration of stability could have been done over a shorter 
duration. In addition, when correlating back the MPGF stability testing 
duration to the averaging time for a monitoring system like a GC that 
can be used to demonstrate compliance with the operating conditions 
laid out in Section III below, the total testing time of the three runs 
should tie back to the time it takes for one GC analysis cycle to occur 
(e.g., 15 minutes in duration). Therefore, based on these reasons, as 
well as in order to minimize emissions from the MPGF stability testing 
requirements, we are finalizing in Section IV(4)(c) that the duration 
of each individual MPGF stability test run must be a minimum of 5 
minutes in duration rather than the longer period of 15 minutes in 
duration that was in the initial framework.
    Regarding the comment to enumerate the performance test information 
in Section IV(4)(b) rather than cross-referencing to Section 
IV(3)(a)(i), we disagree that the change is necessary.
    Comment: One commenter stated that in lieu of using a generic 
olefin gas or an olefinic gas mixture for purposes of the destruction 
efficiency/combustion efficiency performance demonstration specified in 
the framework, the framework should require the performance test to be 
based only on waste gas representative of the proposed flaring 
application, in conjunction with the specific burner type proposed for 
use.
    Response: As discussed in Section IV(3)(a), the framework provides 
the owner or operator with the option to test the MPGF using a 
representative waste gas or a waste gas, such as an olefin gas or 
olefinic gas mixture, that will challenge the performance and smokeless 
capacity of the MPGF. Since MPGF testing is occurring prior to plant 
construction and startup, sufficient representative waste gas may not 
be available to satisfy the testing requirements specified. Therefore, 
we allow olefin gas or olefinic gas mixtures to be considered since 
they represent the olefins industry where the MPGF installations are 
being used and since they have been shown to challenge MPGF 
performance. For this reason, we disagree with the commenter that we 
should amend this requirement in the framework.
    Comment: A few commenters suggested that the EPA allow the AMEL 
framework to provide approval for alternate proposed combustion 
parameters or on-line monitoring requirements and technology.
    One commenter suggested that the framework should provide success 
criteria for submittal and that a clear articulation of the criteria 
the Agency will use to promptly approve an AMEL request is needed.
    Response: As laid out in Section IV (7) below, sources should 
consider all the information laid out in their AMEL application and 
make recommendations 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. Additionally, we note that while the 
framework should provide the regulated community a blueprint for the 
minimum information the Agency needs to review and eventually finalize 
an MPGF AMEL request, the Clean Air Act requires us to provide the 
public with notice and opportunity to comment on the AMEL (see 80 FR 
8023, February 13, 2015, and 80 FR 52426, August 31, 2015, for more 
details) and consider this input before any AMEL request can be 
formally finalized. Because of this statutory requirement, we cannot 
provide any additional language for the regulated community with 
respect to promptly approving an AMEL request without first considering 
public comments regardless of whether or not all the information 
submitted to the Agency exactly follows the framework in Section IV 
below.
    Comment: One commenter suggested that the framework should specify 
that cross-light testing is only required when every burner in the MPGF 
does not have a continuous pilot.
    Another commenter agreed with the cross-light testing specified in 
the framework.
    Response: An MPGF can have hundreds of burners and, when seeking an 
approval of an AMEL request, the owner or operator must demonstrate 
that the system can be operated with a flame present at all times when 
regulated material is routed to the flare and that the burners will 
light and combust this regulated material. To date, the AMEL requests 
for MPGF systems we have approved indicate that cross lighting will be 
used to light the vast majority of individual burners within a given 
stage, which is why this testing requirement is specified in the 
framework. If a future MPGF design will not use cross lighting, the 
owner or operator must demonstrate through testing how the burners 
within a stage will be lit to combust regulated material. Because this 
would be a different design from the MPGF that informed our development 
of the framework, different requirements from those specified in 
Section IV (5) below for the pilot flames and pilot monitoring systems 
may be required for such an MPGF system and these should be conveyed in 
the AMEL request.
    Comment: One commenter suggested that a mechanism similar to the 
``Framework for Streamlining Approval for Future Pressure-Assisted MPGF 
AMEL'' should also be made available for elevated flares that use 
pressure-assisted burners.
    Response: While we understand the commenter's suggestion that the 
Agency clearly prescribe a path forward for evaluating non-MPGF 
pressure-assisted flare designs that may not be able to comply with the 
flare requirements of 40 CFR 60.18(b) or 40 CFR 63.11(b), this request 
is beyond the scope of both OCC's MPGF AMEL request and the framework 
for pressure-assisted MPGF.

III. Final Notice of Approval of OCC's AMEL Request and Required 
Operating Conditions

    Based on information the EPA received from OCC and the comments

[[Page 23484]]

received through the public comment period, we are approving OCC's 
request for an AMEL and establishing operating requirements for the 
pressure-assisted MPGF at OCC's Ingleside, Texas, ethylene plant. The 
operating conditions for OCC's MPGF that will achieve a reduction in 
emissions at least equivalent to the reduction in emissions being 
controlled by a steam-assisted, air-assisted, 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 British thermal units per standard cubic foot (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:
[GRAPHIC] [TIFF OMITTED] TN21AP16.000


Where:

NHVvg = Net heating value of flare vent gas, 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 ([deg]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 [deg]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:
[GRAPHIC] [TIFF OMITTED] TN21AP16.001


Where:

LFLvg = Lower flammability limit of flare vent gas, volume percent 
(vol %).
n = Number of components in the vent gas.
i = Individual component in the vent gas.
[chi]i = Concentration of component i in the vent gas, 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 = [infin], so that [chi]N2/LFLN2 = 0). LFL values 
for common flare vent gas components are provided in Table 1.

    (ii) For MPGF, LFLvg = LFLcz.
    (c) The operator of an 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
----------------------------------------------------------------------------------------------------------------
                                                                                   NHVi (British
                                                     Molecular      MWi (pounds    thermal units   LFLi (volume
                    Component                         formula       per pound-     per standard         %)
                                                                       mole)        cubic foot)
----------------------------------------------------------------------------------------------------------------
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

[[Page 23485]]

 
iso-Butene......................................            C4H8           56.11           2,928             1.8
trans-Butene....................................            C4H8           56.11           2,826             1.7
Carbon Dioxide..................................             CO2           44.01               0         [infin]
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         [infin]
Oxygen..........................................              O2           32.00               0         [infin]
Pentane+ (C5+)..................................           C5H12           72.15           3,655             1.4
Propadiene......................................            C3H4           40.06           2,066            2.16
Propane.........................................            C3H8           44.10           2,281             2.1
Propylene.......................................            C3H6           42.08           2,150             2.4
Water...........................................             H2O           18.02               0         [infin]
----------------------------------------------------------------------------------------------------------------


             Table 2--Accuracy and Calibration Requirements
------------------------------------------------------------------------
                                    Accuracy             Calibration
          Parameter               requirements          requirements
------------------------------------------------------------------------
Flare Vent Gas Flow Rate....  20        Performance
                               percent of flow       evaluation
                               rate at velocities    biennially (every 2
                               ranging from 0.1 to   years) and
                               1 foot per second.    following any
                              5          period of more than
                               percent of flow       24 hours throughout
                               rate at velocities    which the flow rate
                               greater than 1 foot   exceeded the
                               per second.           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         Review pressure
                               percent over the      sensor readings at
                               normal range          least once a week
                               measured or 0.12      for straight-line
                               kilopascals (0.5      (unchanging)
                               inches of water       pressure and
                               column), whichever    perform corrective
                               is greater.           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          2         Calibration
 Calorimeter.                  percent of span.      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 2
                                                     equivalent
                                                     diameters
                                                     downstream from and
                                                     0.5 equivalent
                                                     diameters upstream
                                                     from the nearest
                                                     disturbance. Select
                                                     the sampling
                                                     location at least 2
                                                     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.

[[Page 23486]]

 
Net Heating Value by Gas      As specified in PS 9  Follow the procedure
 Chromatograph.                of 40 CFR part 60,    in PS 9 of 40 CFR
                               appendix B.           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 [deg]C
                                                     (rather than 120
                                                     [deg]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 an 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 3 
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 Section III (6)(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:
    (i) Specify flare design as a pressure-assisted 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 
1 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. Final Framework for Streamlining Approval of Future Pressure-
Assisted MPGF AMEL Requests

    We are finalizing a framework that sources may use to submit an 
AMEL request to the EPA in order to use an MPGF as control devices to 
comply with new source performance standards (NSPS) and national 
emission standards for hazardous air pollutants (NESHAP) under 40 CFR 
parts 60, 61, and 63. At a minimum, sources considering use of an 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

[[Page 23487]]

scenario), MPGF capacity and operation (including number of rows 
(stages), number of burners and pilots per stage and staging curve), 
and how the MPGF will be used (e.g., controls routine flows, only 
controls flows during periods of startup, shutdown, maintenance, 
emergencies).
    (c) Details of typical and/or anticipated waste gas compositions 
and profiles to be routed to the MPGF for 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 NESHAP and/or NSPS, 
applicable standards that allow use of flares, and authority that 
allows the owner or operator to request 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-percent 
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 passive Fourier transform infrared 
spectroscopy (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 achieve a high destruction efficiency 
smokelessly.
    (i) If a performance test is conducted on the burners, 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, 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, barometric pressure, wind speed and direction and 
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 
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) MPGF Stability Testing.
    (a) The operation of an 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 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 
ability to achieve smokeless operation.
    (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 5 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 demonstrate 
instability and complete loss of flame prior to the 5-minute period 
must be reported along with the initial stable flame demonstration. 
Along with destruction efficiency and combustion efficiency, the data 
elements laid out in Section IV(3)(a)(i) above should also be reported.
    (c) Using the results from Section IV(4)(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 LFLcz determined in 
Section IV(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 5 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 Section IV(4)(b) must also be reported.
    (5) MPGF Cross-light Testing.
    (a) Sources must design and carry out 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 Section IV(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, 
barometric pressure, wind speed and direction, and relative humidity), 
and whether there were any observed flare flameouts.
    (6) Flaring Reduction Considerations.
    (a) Sources must make a demonstration, considering MPGF use, on 
whether additional flare reduction measures, including flare gas 
recovery, should be used and implemented.

[[Page 23488]]

    (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 anticipate this framework will enable the Agency to review and 
approve future AMEL requests for MPGF installations in a more 
expeditious timeframe. We note, however, that future AMEL requests are 
still subject to public notice and comment.

    Dated: April 11, 2016.
Janet G. McCabe,
Acting Assistant Administrator.
[FR Doc. 2016-08911 Filed 4-20-16; 8:45 am]
 BILLING CODE 6560-50-P


