The Study Of Calaium Based Desulfurizer In The Circulation Of Smelting Flue Gas Desulfurization

Sulfur dioxide produced by smelting flue gas is one of the major sources of air pollution which caused by the smelting of the steel industry and copper industry. They mainly enriched combustion by oxygen,and the reaction of sulfur with oxygen generated sulfur dioxide, it could form acid rain, mist and other disasters, and could damage farmland soils. Therefore, the pollution of sulfur dioxide has become a top priority of Chinese environmental governance issues.We combined the chemical looping combustion with desulfurization methods,and used calcium sulfide as desulfurizer reduct the SO2 of smelting gas and obtaind elemental sulfur. The solid product calcium sulfate could react with reducing gas of H2 can get CaS achieving desulfurization sorbent circulation.The main research contents and conclusions are as follows:(1)We investigated the optimum conditions of the desulfurizer CaS removal SO2 of simulation smelting gas in a fixed bed.The results showed that:When the concentration of SO2 was 3.45%, the reaction temperature was 500 ℃, reaction airspeed was 250 h-1,the particle size was 62-90 μm,the SO2 removal efficiency of was up to 99.5% in the previous 30 minutes, the SO2 removal efficiency droped down to 91% after 100 minutes. The reaction products is mainly S2 steam, after cooling the final form of elemental sulfur is rhombic sulfur (α-S8).(2)We studied the kinetics of CaS reaction with SO2 in a fixed bed,got desulfurization reaction activation energy (Ea) was 8.55kJ.mol-1.(3)We used the transition state theory to study reaction mechanism of CaS and SO2 in the desulfurization reaction at the B3LYP/6-311G++(d, p) level, and got stable molecular configurations of reactants, intermediates, transition state, products and the corresponding energies of them. The results showed that the reaction of SO2 and CaS formed chain intermediate of IM1 firstly, then after S and O atoms forming chemical bond generated transient state of TS. Through molecular rearrangement and energy configuration generated intermediates of IM2, IM3, IM4, finally generated products of CaSO4 and sulfur. The energy barrier of intermediate of IM4 to P1 was bigger and it was the rate-determining step.