Additives To Strengthen The Coal Slurry Flue Gas Desulfurization Experimental Study

Coal slurry flue gas desulphurization (FGD) is based on aqueous catalytic oxidation. SO2 is removed from flue gas through the reaction with oxygen and coal pyrite. Fe2+/Fe3+ ions leached from pyrite served as catalyst and oxidant in the SO2 removal. At the same time, the content of sulfur in coal pyrite is reduced. In the flue gas desulphurization process, the use of additive can improve the performance of desulfurizer, enhance flue gas desulfurization efficiency, and reduce the investment and running costs of desulfurization system.The flue gas was simulated by mixing N2, O2 and SO2. The influences of different additives on coal slurry FGD process were studied in a bubbling reactor and the enhancing additives were chosen.As the reaction proceeding, the SO2 removal efficiency and the slurry pH value decreased, while the iron leaching rate of slurry increased constantly. The research showed that the more SiO2 used, the smaller desulphurization rate was, but the amount of SiO2 had little influence on the leaching of pyrite. For the coal slime and the high-sulfur coal, additive T0 had different influences on the flue gas desulphurization rates. Additive T0 played a very good buffer role to pH value. Whatever coal slime or the high-sulfur coal, the amount of additive T0 could enhance the leaching rate of iron from coal pyrite. Initial pH value decreased when additive T1 was used. The desulphurization rate was restrained by the increase of ionic strength. M element of T1 enhanced the iron leaching rate. T2, T3 and T4 were all appropriate additives, which could increase the desulphurization rate obviously. They also had some influence on the coal slurry pH value and iron leaching rate. Through experiments, the appropriate concentrations of different additives were determined.