title: Methane emissions from process equipment at natural gas production sites in the United States: pneumatic controllers.
abstract: Emissions from 377 gas actuated (pneumatic) controllers were measured at natural gas production sites and a small number of oil production sites, throughout the United States. A small subset of the devices (19%), with whole gas emission rates in excess of 6 standard cubic feet per hour (scf/h), accounted for 95% of emissions. More than half of the controllers recorded emissions of 0.001 scf/h or less during 15 min of measurement. Pneumatic controllers in level control applications on separators and in compressor applications had higher emission rates than controllers in other types of applications. Regional differences in emissions were observed, with the lowest emissions measured in the Rocky Mountains and the highest emissions in the Gulf Coast. Average methane emissions per controller reported in this work are 17% higher than the average emissions per controller in the 2012 EPA greenhouse gas national emission inventory (2012 GHG NEI, released in 2014); the average of 2.7 controllers per well observed in this work is higher than the 1.0 controllers per well reported in the 2012 GHG NEI.
authors.affiliation: Center for Energy and Environmental Resources, University of Texas at Austin , 10100 Burnet Road, Building 133, M.S. R7100, Austin, Texas 78758, United States.
authors.forename: David T
authors.initials: DT
authors.lastname: Allen
authors.forename: Adam P
authors.initials: AP
authors.lastname: Pacsi
authors.forename: David W
authors.initials: DW
authors.lastname: Sullivan
authors.forename: Daniel
authors.initials: D
authors.lastname: Zavala-Araiza
authors.forename: Matthew
authors.initials: M
authors.lastname: Harrison
authors.forename: Kindal
authors.initials: K
authors.lastname: Keen
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Fraser
authors.forename: A
authors.initials: A
authors.lastname: Daniel Hill
authors.forename: Robert F
authors.initials: RF
authors.lastname: Sawyer
authors.forename: John H
authors.initials: JH
authors.lastname: Seinfeld
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004864:Equipment and Supplies; D008697:Methane / Q000032:analysis*; D059206:Natural Gas / Q000032:analysis*; D061329:Oil and Gas Fields; D014481:United States
chemical_list: D000393:Air Pollutants; D059206:Natural Gas; D008697:Methane