Kinetics Study On Removal Of Mercury From Flue Gas By Aqueous Solution

One type of absorbents, namely sodium chlorite, with known overall superior performance was selected in a bench-scale bubbling reactor in this paper, effect of sodium chlorite concentration, pH value, reaction temperature and mercury concentration in the inlet of reactor on Hg0 removal efficiency were investigated. The results showed that increasing the sodium chlorite concentration, enhancing acidity of solution and high temperature promoted the removal of Hg0. The reaction products were analyzed by ion chromatogram and atomic fluorescence mercury analyzer. The analysis showed that the deoxidization state product of sodium chlorite is mainly Cl-, while the oxidation state product of Hg0 is mainly Hg2+. Using experimental data, the thermodynamics and mass transfer reaction kinetics between Hg0 and sodium chlorite were studied, thenΔGθ, KθandΔHθwere calculated. This could judge that the reaction could progress and the limit was very deep. The kinetics analysis showed that increasing the sodium chlorite concentration and reducing pH value could increase reaction enhancement factor and ratio of KG(Hg0)/kG(Hg0), which indicated that resistance of liquid phase played down and chemical reaction on the impact of mass transfer absorption increased; increasing reaction temperature increased reaction enhancement factor, which explained that increasing temperature promoted chemical reaction, but reduced the ratio of KG(Hg0)/kG(Hg0), which explained that resistance of liquid phase increased.