Euon:\lohil Chemical **Compan~** 3525 O.:ckLT Drive P.O.Bo11 100 Ba}tmvn. Tcxll'775::!::!-0100 VIA CERTIFIED MAIL ANDEMAIL December 19,2014 Ms

.PennyLassiter Office ofAir Quality Planning and Standards (OAQPS) Sector Policies and Programs Division (El43-0l) Refining and Chemicals Group Leader U.S

.Environmental Protection Agency Research Triangle Park, NC27711 EJf(onMobil Clte111icnl Re: Supplemental Information

-RequestforanAlternative Meansof Emission Limitation ("AMEL") for Pressure Assisted Multi-Point Ground Flares ("MPGF')
at Baytown Olefins Plant and MontBelvieu Plastics Plant DearMs

.Lassiter: Exx.onMobil Chemical Company (ExxonMobil)

is respectfully writing to provide supplemental infonnation

tothe Environmental Protection Agency ("EPA")in supportofits requestforanAlternative Meansof Emission Limitation

(" AMEL")

.TheAMEL pertains
tothe flare requirements
of NewSource Perfonnance Standards (NSPS)

,40C

.F.R

.§60

.18 ,and National Emission Standards for Hazardous Air Pollutants (NESHAP)

,40C

.F.R. § 63.11

. On October 21,2014

,Exx.onMobil requested EPA provide anAMELfor Multi-Point Ground Flares (MPGF)
attwofacilities

-Exx.onMobil

'sOlefins Plantin Baytown,Texas (referred
toas
" Baytown Olefins Plant

"or"BOP

" )and ExxonMobil's Plastics Plant

inMont Belvieu, Texas (referred
toas"Mont Belvieu Plastics Plant" or"MBPP

" ). (The requestisattached

.)Wearewriting to update youwith relevant supplemental infonnation since the timeofthe submission. Specifically, below weprovide infonnation identifying the chosen suppliers forthe MPGFs and establishing thatthe selected burners should be deemed equivalent
tothose burners for which thereis publicly available testdata

. Wealso recogni

zethatEPA

'sprocedures provide for anyproposed AMELtobe subject to public notice and comment.As described further below, we respectfully suggestthatEPAutilize the opportunity of proposing the AMEL and taking comment

toallow sufficient flexibility for providing further infonnation and data intothe record that demonstrates equivalency between various MPGF systemsand those that have been subject to testing

. Supplier Selection Exx.onMobil

'stwofacilities
atBOPand MBPParebeing constructed by separate Engineering, Procurement and Construction (EPC) contractors.Each EPChas contracted with global leadersin 1emissions control who have experience with MPGFs, including ground flare design and installation. The MPGF supplier for MBPP is John Zink Company, LLC (John Zink). They are providing

a MPGF system that utilizes Linear Relief Gas Oxidizer burners identified
as LRGO-HC. BOP's MPGF supplier is Zeeco, Inc. (Zeeco). They are providing

a MPGF system utilizing Multi-Jet MJ-4 burners

.Both MPGF systems utilize pressure assisted burners
to effectively entrain and mix ambient air with the waste gas at high velocities. John Zink will supply MBPP with burners that are virtually identical (except for hole area) to burners tested for Dow

1 and Marathon

2 and evaluated
in other publicly available emissions tests. Utilization of this previously tested burner will ensure equivalency for MBPP. Specifically, John Zink has conducted five tests over the period 1982 to 2013 that demonstrate

a Destruction Efficiency of at least 98% (and higher in most cases) for Lower Heating Values above 800 BTU

/ scf and Lower Flammability Limits less than 6.5%. The John Zink supplied burners
at MBPP will achieve equivalent results. Zeeco Burner Design Comparison Although being built by a different vendor, Zeeco's MJ-4 burner is effectively equivalent

in performance

to the John Zink LRGO burner through

a design comparison. Equivalency

is best assessed by comparing the design principles of Burner Type and Burner Geometry for a representative waste gas composition that ensures

a stable, anchored flame. Like the John Zink MPGF burner, Zeeco's burner is pressure assisted

.Both burners mix air and waste gas using pressure energy inherent
in the manufacturing process without steam, air or other assist medium. The burner flame is stabilized and anchored by converging jets above

a bluff body (a shape that creates eddies), resulting in a low pressure zone over
a range of velocities. The primary result of this type design
is stability of the flame over the entire operating envelope. Photos of stable and anchored flames with excellent waste gas
l air mixing from the Dow 2013 test are shown in Figure

1 . Figure
1: Photos of stable, anchored and well-mixed flames from the Dow 2013 test 1 Data obtained from John Zink, Test Report, Flue Gas Emission Testing Support of A TCEQ Alternate Means of Control (AMOC) Application From A Pressure Assisted Process Flare And A Steam Assisted Process Flare, Prepared for John Zink Company, UC. And The Dow Chemical Company Texas Operation, TRC Project No. 199009, November 2013 and John Zink, Test Protocol for The Determination
of Destntction Efficiency of Pressure

-Assisted and Steam Assisted Flare Burners, July 30

,2013. 2 Data obtained from Clean Air Engineering, Performance Test of Steam

·Assisted and Pressure Assisted Ground Flare Burners with Passive FT/R

• Garyville, March 21, 2013.

2Zeeco's BOP Burner Geometry applies design features that achieve high smokeless capacity, correct spacing between burners, and a total footprint of the MPGF array that meets site requirements

.Spidertype arms distribute the waste gas above the burner tip

.Proprietary detailed design factors include the following: number and length of arms, number of holes per arm, hole drilling angles and hole pattern. The hole open area is generally based on the operating scenario with the highest smoke potential. Waste gas composition determines the flame characteristics

.Publicly available tests for plants like BOP's ethylene expansion unit have generally utilized propylene. Propylene

is a surrogate for waste gas hydrocarbons expected
in the design operating envelope. For example, ethylene has both
a wider flammability limit envelope and a higher flame speed than propylene. Therefore, testing with propylene results in conservatively high heating value requirements
for stable combustion

. John Zink and Zeeco both utilize the design feature of a pressure assisted burner stabilized by converging jets above

a bluff body (e

.g .,Burner Type)

.Both companies use spider arm burners with holes drilled and patterned
to achieve smokeless operation over the range of waste gas compositions and across the MPGF array (e.g., Burner Geometry).

In summary, the John Zink test data can be appropriately used to demonstrate equivalency for the Zeeco burners since both suppliers employ the same fundamental design principles. Additional Data ExxonMobil intends to engage in further testing of the burners that will be used at both MBPP and BOP in 2015. These tests are intended
to confirm the stability of the burners and further demonstrate equivalency. ExxonMobillooks forward to sharing the results of the tests with EPA. AMEL Flexibility As EPA considers

a proposed AMEL for MPGFs, ExxonMobil urges the Agency to craft the AMEL with sufficient flexibility
to establish burner equivalency, given that no two facilities will be precisely identical even when they realize equivalent performance results. To this end, we believe that any proposed AMEL should be available
to sites that demonstrate

to EPA's satisfaction that equivalency

to the flare requirements
of New Source Performance Standards (NSPS), 40 C.F.R.

§ 60.18, and National Emission Standards for Hazardous Air Pollutants (NESHAP),
40 C.F.R.

§ 63

.11 is achieved. In particular, we believe at least three considerations
for AMEL flexibility are appropriate
as noted below.
• The AMEL should be available
to sites where evidence of equivalency

is provided. This evidence should allow consideration
of both Burner Type and Burner Geometry. • Site

- specific burner stability testing should be an allowable option of demonstrating that proper design and operability are achievable. • A range of options for monitoring and recordkeeping
of Lower Flammability Limit and Lower Heating Value should be considered and proposed. We believe that utilizing operable standards until future rulemakings are complete

is most appropriate

.Specifically, test data supports that high Destruction Efficiency for pressure assisted MPGFs
is achieved whenever the burners are lit. Proven methods such as camera monitoring and operator visual confirmation are already available
to confirm lit burners

.Subject to Agency review and approval, other ground flare lit flame assurances provided prior to startup should be allowed

. 3Thank you for your consideration
of this request. We appreciate EPA's attention
to this issue which has the potential
to further

a technology with significant environmental benefits while achieving the goals of the applicable NSPS and NESHAP regulations

.We will be standing by to answer any quest

i ons or prov

i de further infonnation and are prepared
to supplement this infonnation

at any time as requested.

If you wish to discuss this request further, please contact me on (281) 834-7728
or beniamin.m

.hurst@exxonmobil

.com

. Sincerely, Benjamin
M
.Hurst Environmental Section Supervisor cc
: Ms

.Brenda Shine Office of Air Quality Planning and Standards (OAQPS) Sector Policies and Programs Division (E143-01) U

.S .Environmental Protection Agency Research Triangle Park, NC 27711 Mr

.Andrew Bouchard Office of Air Quality Planning and Standards (OAQPS) Sector Policies and Programs Division (E 143-01) U

.S .Environmental Protection Agency Research Triangle Park, NC 27711 Mr

.John Blevins Director

, Compliance and Enforcement Division US EPA

, Region

6 1445 Ross Ave. Suite 1200 Mail Code
6 EN Dallas, TX 75202-2733 Mr

.Steve Thompson Associate Director, Airffoxics Inspection and Coordination Branch US EPA, Region

6 1445 Ross Ave. Suite 1200 Mail Code
6 EN-A Dallas, TX 75202-2733

4