Methane Destruction Efficiency of Natural Gas Flares Associated with Shale Formation Wells

Flaring to dispose of natural gas has increased in the United States and is typically assumed to be 98% efficient, accounting for both incomplete combustion and venting during unintentional flame termination. However, no in situ measurements of flare emissions have been reported. We used an aircraft...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science & technology 2014-08, Vol.48 (16), p.9548-9554
Main Authors: Caulton, Dana R, Shepson, Paul B, Cambaliza, Maria O. L, McCabe, David, Baum, Ellen, Stirm, Brian H
Format: Article
Language:English
Subjects:
Air Pollutants - analysis
Carbon Dioxide - analysis
Efficiency
Emissions
Energy efficiency
Humans
Methane
Methane - analysis
Natural Gas
North Dakota
Oil shale
Pennsylvania
United States
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Flaring to dispose of natural gas has increased in the United States and is typically assumed to be 98% efficient, accounting for both incomplete combustion and venting during unintentional flame termination. However, no in situ measurements of flare emissions have been reported. We used an aircraft platform to sample 10 flares in North Dakota and 1 flare in Pennsylvania, measuring CO2, CH4, and meteorological data. Destruction removal efficiency (DRE) was calculated by assuming a flare natural gas input composition of 60–100% CH4. In all cases flares were >99.80 efficient at the 25% quartile. Crosswinds up to 15 m/s were observed, but did not significantly adversely affect efficiency. During analysis unidentified peaks of CH4, most likely from unknown venting practices, appeared much larger in magnitude than emissions from flaring practices. Our analysis suggests 98% efficiency for nonsputtering flares is a conservative estimate for incomplete combustion and that the unidentified venting is a greater contributor to CH4 emissions.
ISSN:0013-936X
1520-5851
DOI:10.1021/es500511w