Study on the Removal of Gaseous Mercury from Coal-Fired Flue Gas by Calcium Salts

Abstract

Gaseous mercury in coal-fired flue gas is very harmful to human, animals and plants although in low density. This paper study the effect of the removal of gaseous mercury by co-firing of coal and calcium salts on the one-dimensional pulverized coal combustion experiment system. In this experiment, three kinds of calcium salts are chosen. We test the content of gaseous mercury in coal-fired flue gas respectively by adding CaO,Ca(OH) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and calcium acetate and analysis the removal effect of gaseous mercury influenced by the kinds of calcium salts, the different proportion and Ca/s ratios. The results show that: when add calcium salts in pulverized coal, in the flue gas, because SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> has apparent effect on catalytic effect of calcium salts, calcium salts remarkably upgrade the adsorption of Hg. It is easy to form active zone on the surface of calcium material, realizing the physics and chemistry double effect combined of calcium salts and mercury. Calcium salts are effective on mercury removal. The valence of Hg in the flue gas has great influence on mercury pollution. This paper analysis the influences of different calcium salts on the valence of Hg.