Ethylene–SO2 interaction under sooting conditions: PAH formation

Abstract

The formation of polycyclic aromatic hydrocarbons (PAH) and soot from the pyrolysis of ethylene in the presence of different amounts of sulphur dioxide (SO2) and at different reaction temperatures (1075–1475K) was studied. The sixteen PAH classified by the Environmental Protection Agency (EPA) as priority pollutants were quantified by gas chromatography–mass spectrometry (GC–MS). Soot formed was collected on a filter at the reactor outlet. The concentration of the main gases obtained was also determined. The harmful potential or toxicity of the EPA–PAH, through the B[a]P-eq, has been evaluated together with the yield to EPA–PAH. The main results show that for a low SO2 concentration (0.3%), the formation of EPA–PAH and toxicity increase, while high concentrations of SO2 decrease the yield to soot, EPA–PAH and B[a]P-eq concentration. The highest concentration of SO2 shifts the maximum concentration of EPA–PAH to lower temperatures.