Characterization of volatile hydrocarbons emmtted to air from a cat-cracking refinery

Hydrocarbons (C2–C8) emitted to air from a Swedish cat-cracking petroleum refinery have been studied. Samples were taken by using adsorbent cartridges and personal air sampling pumps, and were analyzed by gas chromatography. The hydrocarbon emissions from the fluid catalytic cracking unit (FCCU) were found to consist of approximately 15–20% alkenes, 5% or less arenes, and 80% alkanes. Alkenes are of great interest with respect to the formation of photooxidants. The alkenes were mainly propene, butenes and pentenes. For most of the samples, propene was the single most prominent alkene followed by trans-2-butene. All four butene isomers were separated. Propane and methylpropane were the major alkanes from the FCCU. The proportions of hydrocarbons in the mixed emissions from the aggregated other refinery processes were much less uniform than those from the FCCU.