ADSORPTION OF MERCURIC-CHLORIDE VAPORS FROM INCINERATOR FLUE-GASES ONCALCIUM HYDROXIDE PARTICLES

The adsorption of mercuric chloride vapours on a fixed bed of calcium hydroxide fine particles has been experimentally studied. The study ha s been conducted at laboratory scale using simulated flue gases, const ituted of mercuric chloride vapours in nitrogen, which have been in co ntact with a Ca(OH)2 fixed bed. The effect of the bed temperature, the inlet HgCl2 concentration, and the relative gas-solid velocity on the HgCl2 removal efficiency has been studied. The experimental results i ndicated that high removal efficiencies of up to 95% can be obtained. The bed temperature has been found to be the most relevant parameter p articularly as the experimental results show that the lower the bed te mperature, the higher the removal efficiency. Moreover, the removal ef ficiency increases when the HgCl2 concentration in the inlet gas incre ases and when the relative gas-solid velocity decreases. A model based on a simplified expression of the Freundlich adsorption isotherm has been proposed, which is able to describe quite accurately the dependen ce of HgCl2 removal efficiency on the parameters investigated.