Wet–dry process for HCl removal from flue gas: experimental study of the operating parameters

Wet‐dry process of hydrogen chloride removal from flue gas has been studied at pilot scale. Hot gas produced by methane burner, added with gaseous hydrogen chloride, is contacted by an aqueous suspension of calcium hydroxide in a cylindrical steel vessel 0.25 m I.D. and 4 m high. The effects of feed ratio Ca(OH)2/HCl, hydrogen chloride concentration in the inlet gas, operating temperature and residence time on the amount of hydrogen chloride removed have been exstensively investigated. The effect of inside wall fouling by Ca(OH)2 has also been evaluated. The experimental results show that the overall amount of hydrogen chloride removed increases when the feed ratio and the gas inlet concentration are increased and the operating temperature is decreased. However, the HCL removal does not seem affected by the residence time within the short interval investigated.