PIONEERNATURALRESOURCESMarch30,2015EnvironmentalProtectionAgencyEPADocketCenter(EPA/DC)Attention:DocketIDNo.EPA-HQ-OAR-2014-0738Mailcode28221T1200PennsylvaniaAvenue,N.W.Washington,D.C.20460Submittedelectronicallyat:www.regulations.govPioneerNaturalResourcesUSA,Inc.5205N.0'ConnorBlvd.,Suite200Irving,Texas75039-3746Tel:(972)444-9001Fax:(972)969-3587Re:PioneerNaturalResources'CommentsonEPA'sReceiptofApprovalRequestsfortileOperationofPressure-AssistedMulti-PointGroundFlareTec/mology;RequestforComments;80FederalRegister8023(February13,2014);DocketIDNo.EPAJIQ-OAR-2014-0738DearSirorMadam:PioneerNaturalResourcesUSA,Inc.("Pioneer")greatlyappreciatestheopportunitytosubmitcommentsinresponsetotheEnvironmentalProtectionAgency's("EPA")RequestforCommentsonDowandExxonMobil'sAlternativeMeansofEmissionLimitation("AMEL")requestsformulti-pointgroundflares("MPGF")duringtheformalpubliccommentperiod.PioneersupportsthependingAMELrequests.Pioneerisalargeindependentoilandgasexplorationandproductioncompany,headquarteredinDallas,Texas.Thecompanyemploysapproximately4,000peopleandproducesapproximately180,000barrelsofoilequivalentperday.PioneeristhelargestoperatorintheSpraberry/WolfcampoilfieldinWestTexasandisoneofthemostactivedrillersthereandintheSouthTexasEagleFordShaleplay.Complementingtheseareas,PioneerhasoperationsintheEdwardstrendareaandtheWestPanhandlegasfieldlocatedinTexas.Pioneeralsohasexploration,development,andoilandgasproductionactivitiesintheRatongasfieldlocatedinsouthernColorado.InsomeofitslargeandcomplexfacilitiesinitsSouthTexasEagleFordplay,PioneercurrentlyoperatessonicflaresmanufacturedbyGBACorona.AsEPAacknowledges,pressureassistedflaresarealsoknownassonicflaresbecausetheexitvelocityduringperiodsofhigh-pressureEPA Docket Center (EPA/DC) Pioneer Natural Resources' Comments

Re: EPA's AMEL Request for Comments Docket

ID No. EPA-HQ-OAR-2014-0738 March 30, 2015 Page2of3 feeds

is at sonic velocities

. 1 Pioneer

is therefore very familiar with the technologies proposed

in the AMEL requests

as well as the characteristic

of sonic flares having velocities greater than those set in 40 CFR Parts 60 and 63, and EPA's resulting concerns. Pioneer offers the following data and analysis

to assist

in the evaluation

of the AMEL's

in question,

as well as to prompt

a rule revision

or at least guidance that would allow the use of these newer and more technologically-advanced

and environmentally-friendly

sonic flares

in addition

to those flares currently allowed

. In order
to address EPA's concerns with sonic flares, these comments include the manufacturer

- provided technical points
as well

. Pioneer understands
that EPA's primary concerns
are flame instability, flame liftoff

, and/or flameout

at the high velocities. Though Pioneer agrees that these concerns have some merit for high velocity sonic flares that would exceed the existing
tip velocity requirements

of 40 CFR §60.18 and 40 CFR §63.ll(b), Pioneer has experience with several sonic flare installations which do not inherently result
in potential
for flameout and/or degraded combustion

. Further, Pioneer strongly contends that high pressure sonic flares, including MPGFs, can be designed such that combustion efficiency

is improved
and potential risk of flame instability

is mitigated. Based
on Pioneer's operational knowledge

of sonic flares

in its operations,

as well as recent technical discussions
with GBA Corona, Pioneer supports
the approval

of the AMEL applications

for use ofMPGFs. As mentioned above, Pioneer operates GBA Corona's "Corona Sonic Flare" (CSF)

at several large and complex Eagle Ford facilities

to control

a high BTU hydrocarbon

gas stream(> 1300 BTU/SCF) which

is routed

to flare during maintenance, startup, and shutdown (MSS) and emergency situations. Multiple flare designs experienced issues

in achieving smokeless combustion

for our applications. However,

the GBA Corona CSF flares have been able
to achieve smokeless combustion since installation

by virtue of their sonic velocities.

As may be the case with Dow and ExxonMobil's MPGF's,
the high pressure sonic flares use high gas velocity

to increase momentum entraining large quantities

of air. Pioneer has operated five of these sonic flares since 20 12 and not

a single flameout event has occurred

in that time period. There are certain potential environmental benefits
of sonic flares worth noting

. Sonic flares have less radiation
and therefore,

a reduced boom length/stack height; they generally will have less emissions because they require less purge and no gas assist and they have efficient combustion; and they also eliminate
the need for the utilities required
for operating

an air blower for an airassisted flare. 1 80 Fed

. Reg

. 8028EPA Docket Center (EPA/DC) Pioneer Natural Resources' Comments

Re

: EPA's AMEL Request for Comments Docket
ID No

. EPA-HQ-OAR-2014-0738 March 30, 2015 Page3of3 Pioneer understands

the reasons behind EPA's concerns about combustibility

(net heating value) and flammability

of the waste stream

as potential causes
of flameout and/or less efficient combustion; however, Pioneer

is not commenting

on the appropriateness

of the precise values that EPA

is proposing

for both applications. Pioneer

is, however, asserting that

a highly combustible

gas will completely mitigate
the combustion concerns which serve
as the basis for the tip velocity requirements

in both §60.18 and §63 .11 (b). In conclusion, Pioneer supports
the approval

of Dow and ExxonMobil's AMEL applications which would allow

a flare to operate with tip velocity

in excess
of those defined

in §60

. 18 and §63

. 11 (b)

. Furthermore, Pioneer requests that EPA strongly consider revisions

to both regulations

as they pertain

to tip velocity requirements placed
on combustion control devices used for NSPS and MACT authorized sources, and perhaps more importantly,

as they are currently considered

the flare BACT standard
by which many state air permitting agencies
are restricted

in authorizing industrial activity within their jurisdictions. These regulatory

tip velocity requirements

are outdated,
too generic

in nature, and significantly hinder the efficiencies
and potential environmental benefits achieved

by sonic flares and perhaps other emerging technologies. Pioneer greatly appreciates

the opportunity

to submit these comments

to EPA's above-referenced AMEL Request
for Comments

. Please contact

us

i f you have any questions

or require additional information

. Aaron arez Sr. Environmental Specialist Air Permitting-
EFS Midstream Email: Aaron.Alvarez@pxd.com Phone: 972

. 969.5986 **~.£t.kt<.<-<.-C. ~** 

. Gretchen

C

. Kern, J.D

. Sr. Regulatory
and Environmental Policy Advisor Sustainable Development Email

: Gretchen.Kern@pxd.com Phone: 972.969.3936