Effect Mechanism of O2 and H2O on SO2 Conversion and Existence Form in Activated Coke

摘要

Activated coke flue gas desulfurization technology(FGD) which has the advantages of water-saving and pollutant recyclable utilization is considered the important development direction of FGD. In this paper, effect mechanism of O2 andH2O in simulated flue gas on SO2 conversion and existence form in activated coke is studied through the methods of fixed bed and ion chromatography. The research results show that:O2 makes some chemical adsorbed SO2 be oxidized to SO3whose adsorption pattern is different from that of SO2. The formation of SO3 makes SO2 adsorption active sites vacant and creates the conditions to further adsorb SO2. SO3 can react with H2O (g) to H2SO4 (g). The condensation of sulfuric acid vapor promotes the reaction of SO3 and H2O (g), and further promotes the oxidation of SO2. Increase of O2 concentration can reduce the diffusion resistance and increase the probability of oxygen diffusion to the active sites, Excess H2O (g) in flue gas forms excess water film which can plug the pores and flood active sites, and ultimately hinder the diffusion of SO2 and O2to micro pores. O2 and H2O are necessary in AC desulfurization process. Reaction of SO3 and H2O (g) and condensation of sulfuric acid vapor are the dynamic of AC desulfurization process. Oxidation reaction of chemical adsorbed SO2 and O2is the rate controlling step of the whole process.