Combined DeSOx/DeNOx reactions on a copper on alumina sorbent-catalyst. 2. Kinetics of the DeSOx reaction

The kinetics of SO2 removal from flue gas and adsorption in the form of regenerable surface sulfate species on a Cu/Al2O3 sorbent-catalyst were detd. according to spectroscopic evidence showing the formation of 2 sulfate species linked to Cu or Al species, resp. Various kinetic reaction networks, with parallel or consecutive 1st- or 2nd-order reactions, are compared. The best fit of the results was found for a reaction model involving a 1st step of oxidn. of chemisorbed SO2 to chemisorbed SO3 on Cu, followed by further reaction of the chemisorbed SO3 with a 2nd neighboring Cu species to form a sulfate species linked to Cu or a surface transfer to neighboring Al species to form sulfate species linked to Al, leaving a reduced Cu site that is rapidly regenerated by gaseous O. This reaction model is in good agreement with reactivity and spectroscopic evidence on the reaction mechanism. [on SciFinder(R)]