REMOVAL OF TOXIC TRACE ELEMENTS FROM COAL COMBUSTION EFFLUENT GAS

摘要

Emission control of the toxic trace elements, arsenic, beryllium, cadmium, mercury, lead, and selenium, in pulverized coal combustion is reported. A baghouse system was installed on an experimental combustor firing 500 lb/hr of pulverized coal to reduce these emissions by adsorption/condensation of the trace elements onto a fly ash layer. Baghouse temperature, baghouse pulse cycle, and combustion excess-air level were varied to determine their effect on the ability of the fly ash to retain these trace elements. Experimental data show that near complete retention of Hg and Se in combustion gas by fly ash is possible with significant retention of the other trace elements studied. Whereas data on coal-fired power plants equipped with conventional electrostatic precipitators indicate that over 80% of the mercury in the coal feed escaped to the atmosphere while the other trace elements were lost at varying degrees.