Among globally relevant combustion sources, such as diesel emission and biomass burning, gas flaring remains the most uncertain. In this study, small-scale turbulent gas flaring was used to characterize particulate emissions produced under different operating conditions, such as various burner diameters and exit velocities. The composition of the fuel was also varied by modifying the percentage of methane, ethane, propane, butane, N2, and CO2, which are the predominant constituents in the upstream oil and gas industry. A broad suite of physical, chemical, and microscopic techniques was employed for analysis, and scanning electron microscopy showed the generated soot agglomerates to be composed of primary spherules that were 30 ± 10 nm in diameter. Additionally, high-resolution transmission electron microscopy, used to determine the length, tortuosity, and separation of individual graphene fringes on the primary particles, revealed a fullerenic, multiple-nuclei internal structure. Single-particle analysis revealed the dominance of elemental carbon vs. oxidized and metal-contaminated particles, and infrared spectroscopy showed the presence of alkanes and aromatics with oxygenated compounds. Intercomparing the microstructure and the composition, we also concluded that the vast majority of particles are hydrophobic.

Elemental composition, Fullerenic internal structure, Gas flaring, Graphitic content, Hygroscopicity, Soot
Aerosol and Air Quality Research
Department of Mechanical and Aerospace Engineering

Popovicheva, O. (Olga), Timofeev, M. (Mikhail), Persiantseva, N. (Natalia), Jefferson, M.A. (Melina A.), Johnson, M.R, Rogak, S.N. (Steven N.), & Baldelli, A. (Alberto). (2019). Microstructure and chemical composition of particles from small-scale gas flaring. Aerosol and Air Quality Research, 19(10), 2205–2221. doi:10.4209/aaqr.2019.04.0177