Environmental Protection Agency EPA Docket Center (EPA/DC) 

Attention: Docket ID No. EPA-HQ-OAR-2014-0738 

Mail code 28221 T 

1200 Pennsylvania Avenue, N.W. 

Washington, D.C. 20460 

Submitted electronically at: www.regulations.gov 

Re: Pioneer Natural Resources' Comments on EPA's Receipt of Approval Requests for 

tile Operation of Pressure-Assisted Multi-Point Ground Flare Tec/mology; Request 

for Comments; 80 Federal Register 8023 (February 13, 2014); Docket ID No. EPAJIQ-OAR-2014-0738 

Dear Sir or Madam: 

Pioneer Natural Resources USA, Inc. ("Pioneer") greatly appreciates the opportunity to submit 

comments in response to the Environmental Protection Agency's ("EPA") Request for 

Comments on Dow and ExxonMobil's Alternative Means of Emission Limitation ("AMEL") 

requests for multi-point ground flares ("MPGF") during the formal public comment period. 

Pioneer supports the pending AMEL requests. 

Pioneer is a large independent oil and gas exploration and production company, headquartered in 

Dallas, Texas. The company employs approximately 4,000 people and produces approximately 

180,000 barrels of oil equivalent per day. Pioneer is the largest operator in the 

Spraberry/Wolfcamp oil field in West Texas and is one of the most active drillers there and in 

the South Texas Eagle Ford Shale play. Complementing these areas, Pioneer has operations in 

the Edwards trend area and the West Panhandle gas field located in Texas. Pioneer also has 

exploration, development, and oil and gas production activities in the Raton gas field located in 

southern Colorado. 

In some of its large and complex facilities in its South Texas Eagle Ford play, Pioneer currently 

operates sonic flares manufactured by GBA Corona. As EPA acknowledges, pressure assisted 

flares are also known as sonic flares because the exit velocity during periods of high-pressure 
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. 

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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 if 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 

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Gretchen C. Kern, J.D. 

Sr. Regulatory and Environmental Policy Advisor 

Sustainable Development 

Email: Gretchen.Kern@pxd.com 

Phone: 972.969.3936