The effect of sulfur dioxide on soot and polycyclic aromatic hydrocarbon formation in premixed ethylene flames

Abstract The effects of sulfur dioxide on soot formation and on concentrations of polycyclic aromatic hydrocarbon (PAH) species have been investigated in a premixed ethyleneoxygenargon flame. Sulfur dioxide reduces PAH concentrations and reduces the soot volume fraction without affecting the number density, coagulation rate, or the decay constant for the surface reactivity of the soot particles. These effects parallel those previously observed for oxygen addition to rich flames, and are consistent with consumption of SO 2 in the sooting region. The oxygen and sulfur atoms become available for the formation of compounds such as CO 2 and CS 2 , thereby reducing the amount of carbon available for soot growth.