Experimental Study on Demercurization Performance of Wet Flue Gas Desulfurization System

The demercurization performance of wet flue gas desulfurization (WFGD) system was investigated by measuring mercury concentrations at the inlet and Outlet of WFGD system with a QM201H mercury analyzer The selected desulfurizer included NH3 center dot H2O, NaOH, Na2Co3, Ca(OH)(2) and CaCO3. The influences of adding oxidant and coagulant such as KMnO4. Fenton reagent, K2S2O8/CuSO4 and Na2S into desulfurization solutions were also studied. The results show that elemental mercury is the main component of gaseous mercury in coal-fired flue gas, and the proportion of oxidized mercury is leas than 36% Oxidized mercury Could be removed by WFGD system efficiently. and the removal efficiency could amount to 81.1%-92.6% However, the concentration of elemental mercury slightly increased at the outlet of WFGD as a result of its insolubility and re-emission Therefore, the removal efficiency of gaseous merctuy is only 13.3%-183%. The mercury removal efficiency of WFGD system increased with increasing the liquid-gas ratio. In addition, adding KMnO4, Fenton reagent, K2S2O8/CuSO4 and Na2S into desulfurization solutions could increase the mercury removal efficiency obviously. Various additives have different effects, and Na2S is demonstrated to be the most efficient, in which a niercury removal efficiency of 67.2% can be reached.