Kinetic modelling of homogeneous low temperature multi-pollutant oxidation by ozone: The importance of SO and HCl in predicting oxidation

A detailed kinetic model consisting of 126 reactions and 37 species modelled homogeneous low temperature multi-pollutant oxidation in flue gases by ozone. The kinetic model includes the oxidation and chlorination of key flue-gas components, as well as reactions involving SO. An important and previously unrecognized pathway of homogeneous Hg oxidation mechanism includes Hg reactions involving oxygen-containing compounds and chlorine-containing compounds. Analyses by sensitivity simulations revealed that the pathway Hg+Cl=HgCl and HgCl+Cl2=HgCl2+Cl is more significant than some of the key reactions in the kinetic mechanism proposed in the literature except Hg+NO3=HgO+NO2, which indicates the possibility to promote the Hg removal by adding HCl in the inlet stream. Studies on the effects of SO show that SO violently prevents NO consumption through the pathway SO+NO2=NO+SO2, even the net NO produced under the condition of low O3 concentration and high SO concentration.