AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Atmospheric Impacts of Hydraulic Fracturing: Aerosol Production from Flowback Fluid
Jeffrey Bean, DONGYU WANG, Sahil Bhandari, Lea Hildebrandt Ruiz, University of Texas at Austin
Abstract Number: 193 Working Group: Aerosol Chemistry
Abstract Natural gas production has increased dramatically in the United States in recent years due to technological advances such as horizontal drilling and hydraulic fracturing. However, the environmental impacts of hydraulic fracturing remain poorly understood. One such process is the storage of flowback fluid. Though mostly composed of water, flowback fluid typically contains a multitude of organic and inorganic compounds, many of which can evaporate. Atmospherically vented storage tanks are a source of hydrocarbon and other emissions, which could contribute to local and regional production of aerosol.
We report results from laboratory studies which were conducted to assess the atmospheric impacts of flowback fluid. The concentration of total volatile organic carbon determined for twelve hydraulic fracturing flowback fluid samples ranged from 0 to 114 mg carbon/L. The formation of particulate matter under atmospheric oxidative conditions was quantified by evaporating samples into an environmental chamber. During photo-oxidation using HONO as a source of OH and NOx, ammonium nitrate and organic aerosol were formed, indicative of ammonium contents in flowback fluid. In several experiments the amount of ammonium nitrate formed was greater than the amount of organic aerosol, suggesting the importance of ammonia emissions to the atmospheric effects of flowback fluid. A high resolution time of flight chemical ionization mass spectrometer (HR-ToF-CIMS) was used in combination with a filter inlet for gas and aerosols (FIGAERO) to identify compounds in the gas and particle phases following photo-oxidation. The majority of gas-phase compounds observed with the HR-ToF-CIMS contain 8-13 carbon atoms but many particle-phase compounds contain more than 13 carbon atoms. The study highlights the potential of emissions from hydraulic fracturing activity to impact atmospheric composition.