Experimental Study On Synergistic Removal Of SO₃ And Hg⁰ From Flue Gas By Semi-dry Flue Gas Desulfurization

In view of the severe situation of air pollution in China,the flue gas treatment in non-electric industry has attracted great attention.In iron and steel industry,sintering pellet process takes up a large proportion of pollutant discharge in non-electric industry.Semi-dry desulfurization technology has been widely used in the flue gas desulfurization of sintered pellets due to its advantages of small area,relatively simple equipment and stable operation.However,this process has some shortcomings,such as low removal efficiency and inability to achieve simultaneous removal of Hg0 and SO3.Therefore,according to the characteristics of steel industry flue gas,the research and development of efficient integrated multi-pollutant removal technology has become a hot spot of current steel industry flue gas pollution control.In this paper,the semi-dry fixed bed reaction platform was built,and SO2,Hg0 and SO3 in the simulated flue gas were removed in the laboratory.The oxidant type,volume ratio,mass fraction,pH,reaction temperature and calcium-based absorbent were investigated through experiments.Influencing factors such as mass,flue gas intake flow rate,and the effect of semi-dry method on the absorption of pollutants in the pellet smoke.The results showed that sodium hypochlorite and sodium chlorite were used as composite oxidants,and the ratio of composite oxidant was 1:0.5,mass fraction was 3%,pH=5,reaction temperature was 110 ℃,mass of absorbent was 3g,and composite oxidant was injected.Under the optimal experimental conditions with a rate of 160μL/min and a total flue gas flow of 1.2 L/min,the removal efficiencies of SO2 and Hg0 were 97.96% and 63.12%,and SO3 removal efficiencies was 100%.respectively,and the results were analyzed by multi-factor experiments combined with SEM and XRD.It proves that the semi-dry system of calcium-based absorbent and composite oxidant has a good removal effect on pollutants,which provides a reference for the steel industry to remove multiple pollutants in the flue gas.