“Calcium bisulfite oxidation rate in the wet limestone–gypsum flue gas desulfurization process”

In this paper oxidation of calcium bisulfite in aqueous solutions was studied, in connection with the limestone - gypsum flue gas desulfurization process. Experimental measurements of the oxidation rate were carried out in a laboratory scale stirred reactor with continuous feeding of both gas and liquid phase. A calcium bisulfite clear solution was used as liquid phase, and pure oxygen or mixtures of oxygen and nitrogen were used as gas phase. Experiments were carried out at T ) 45 ° C varying the composition of the liquid phase and the oxygen partial pressure. Manganous sulfate was used as catalyst. The analysis of the experimental results showed that the kinetics of bisulfite oxidation in the presence of MnSO 4 follow a parallel reaction mechanism, in which the overall reaction rate can be calculated as the sum between the uncatalyzed rate ( 3 / 2 order in bisulfite ion) and the catalyzed reaction rate (first order in manganous ion).