Black Carbon Emissions from Associated Natural Gas Flaring

作者：Weyant Cheryl L^*; Shepson Paul B; Subramanian R; Cambaliza Maria O L; Heimburger Alexie; McCabe David; Baum Ellen; Stirm Brian H; Bone Tami C

来源：Environmental Science & Technology, 2016, 50(4): 2075-2081.

DOI：10.1021/acs.est.3b04712

Approximately 150 billion cubic meters (BCM) of natural gas is flared and vented in the world annually, emitting greenhouse gases and other pollutants with no energy benefit. About 7 BCM per year is flared in the United States, and half is from North Dakota alone. There are few emission measurements from associated gas flares and limited black carbon (BC) emission factors have been previously reported from the field. Emission plumes from 26 individual flares in the Bakken formation in North Dakota were sampled. Methane, carbon dioxide, and BC were measured simultaneously, allowing the calculation of BC mass emission factors using the carbon balance method. Particle optical absorption was measured using a threewavelength particle soot absorption photometer (PSAP) and BC particle number and mass concentrations were measured with a single particle soot photometer. The BC emission factors varied magnitude, with an average and uncertainty range of 0.14 0.12 g/kg hydrocarbons in associated gas and a median of 0.07 g/kg which represents a lower bound on these measurements. An estimation of the BC emission factor derived from PSAP absorption provides an upper bound at 3.1 g/kg. These results are lower than previous estimations and laboratory measurements. The BC mass absorption cross section was 16 12 m(2)/g BC at 530 nm. The average absorption Angstrom exponent was 1.2 0.8, suggesting that most of the light absorbing aerosol measured was black carbon and the contribution of light absorbing organic carbon was small.

• 出版日期2016-2-16