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Title: Multiday Measurements of Pneumatic Controller Emissions Reveal the Frequency of Abnormal Emissions Behavior at Natural Gas Gathering Stations

Journal Article · · Environmental Science & Technology Letters (Online)
ORCiD logo [1]; ORCiD logo [1];  [1];  [2];  [2];  [3];  [4];  [5]; ORCiD logo [6]
  1. Energy Institute, Colorado State University, Fort Collins, Colorado 80524, United States
  2. AECOM, Austin, Texas 78729, United States
  3. SLR Consulting, New Braunfels, Texas 78312, United States
  4. Energy Institute, Colorado State University, Fort Collins, Colorado 80524, United States, Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80524, United States
  5. Physics & Engineering, Fort Lewis College, Durango, Colorado 81301, United States
  6. Chemical Engineering, The University of Texas, Austin, Texas 78712, United States

Gas-driven pneumatic controllers (PCs) and actuators used in all natural gas sectors vent uncombusted natural gas to the atmosphere during operation and contribute approximately 20% of methane emissions from the natural gas supply chain. In this study, multiday measurements were utilized to better characterize PC emission rate profiles. Emissions from 72 PCs were successfully measured at 16 gathering compressor stations for an average of 76 h each between June 2017 and May 2018. These measurements are the first known multiday recordings of emissions of PCs in situ at operating natural gas facilities. These measurements revealed previously unidentified emissions behaviors. A review by an expert panel identified 30 PCs (42% of measured devices) that exhibited abnormal emissions behavior, including 25 of 40 intermittent-vent PCs, 5 of 24 low-bleed PCs, and 0 of 8 high-bleed PCs measured. Abnormally operating PCs had emissions substantially higher than the emissions of those operating normally. For intermittent-vent PCs, abnormally operating PCs showed average emission rates of 16.1 standard ft3 h₋1 (scfh, whole gas) versus 2.82 scfh for normally operating PCs. Sampling simulations also indicate that measurements of ≥24 h are necessary to quantify emissions to within 20% [11₋31%] of a PC’s long-term average emissions. Because of potential biases in sample size and diversity and corrections for measurement errors, we recommend these data be utilized for only a qualitative understanding of PC behavior and not for developing emission factors.

Research Organization:
Colorado State Univ., Fort Collins, CO (United States)
Sponsoring Organization:
USDOE Office of Fossil Energy and Carbon Management (FECM); USDOE Office of Fossil Energy (FE)
Grant/Contract Number:
FE0029068
OSTI ID:
1512833
Alternate ID(s):
OSTI ID: 1525784
Journal Information:
Environmental Science & Technology Letters (Online), Journal Name: Environmental Science & Technology Letters (Online) Vol. 6 Journal Issue: 6; ISSN 2328-8930
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 8 works
Citation information provided by
Web of Science

References (8)

Methane Emissions from Process Equipment at Natural Gas Production Sites in the United States: Pneumatic Controllers journal December 2014
Assessment of Uinta Basin Oil and Natural Gas Well Pad Pneumatic Controller Emissions journal January 2017
Methane Emissions from the Natural Gas Transmission and Storage System in the United States journal July 2015
Pneumatic Controllers in Upstream Oil and Gas journal August 2014
Methane Emissions from Natural Gas Compressor Stations in the Transmission and Storage Sector: Measurements and Comparisons with the EPA Greenhouse Gas Reporting Program Protocol journal February 2015
Temporal variability largely explains top-down/bottom-up difference in methane emission estimates from a natural gas production region journal October 2018
Direct Measurements Show Decreasing Methane Emissions from Natural Gas Local Distribution Systems in the United States journal March 2015
Measurements of methane emissions at natural gas production sites in the United States journal September 2013

Figures / Tables (3)