Abstract View
The Effect of Sodium-laden Solutions on Particulate Emissions from Gas Flares
CAMERON ROTH, Bradley Conrad, Matthew Johnson, Carleton University
Abstract Number: 391
Working Group: Combustion
Abstract
Flaring in the upstream oil and gas industry (UOG) is the process by which unwanted gases are disposed through combustion in an open-atmosphere flame. During and after flowback operations at hydraulically fractured wells, gas must be separated from produced oil and other liquids prior to combustion. Field experiments have shown that this separation process is imperfect, allowing liquids to be entrained in the gas stream and subsequently combusted. These liquids vary spatiotemporally but are typically composed mainly of formation water. Despite this variability, ions such as sodium and chlorine are consistently present in strong concentrations. Previous experiments studying lab-scale flames doped with sodium aerosols have shown that sodium can significantly disrupt the combustion process, strongly influencing the production of particulate emissions and carbon conversion efficiency (CCE) of the flare. Recent research has also identified that the morphology and, hence, optical properties of carbonaceous particles emitted from sodium-doped flames differ from dry flames.
This work presents an investigation into the effects that entrained sodium-laden formation water may have on particulate emissions from flares in the UOG industry. Experiments using a hydrocarbon gas mixture representative of UOG flaring in Alberta, Canada are conducted at the Carleton University Flare Facility. Aqueous solutions containing NaCl or NaOH at 0.25−8.0%m/m are atomized into the flare gas stream prior to combustion. Particle mass concentrations and optical coefficients in the diluted combustion products are simultaneously measured to infer relative emission rates and optical properties of emitted particulate. Gas-phase instrumentation permits simultaneous calculation of flare CCE and gas-phase emissions. These studies identify significant, and sometimes contrasting effects of NaCl and NaOH solutions on the propensity of a flare to emit particulate matter and the CCE of the flare. The implications of the effective single scattering albedo of emitted particulate and concomitant emissions of greenhouse gases are discussed.