Catalytic oxidation of calcium bisulfite in the wet limestone–gypsum flue gas desulfurization process

Abstract

A study on the oxidation of calcium sulfite catalyzed by Mn 2+ is presented in this paper. A laboratory-scale well-mixed thermostated reactor was used, with continuous feeding of both gas and liquid phase. The gas phase was a mixture of oxygen and nitrogen, with O 2 partial pressure varying from 5.1 to 40.5 kPa. The liquid phase was obtained by mixing inside the reactor two separate aqueous solutions, one obtained by dissolving Ca(OH) 2 into a SO 2 solution, and the other one containing manganous sulfate. The temperature was kept constant in all the experiments at 45°C. The results show that increasing catalyst concentration, the transition takes place from slow kinetic to slow diffusional and eventually to fast reaction regime.