Purificn. of effluent gas from rubbish combustion - contg. fly ash, heavy metal, acid gases etc. by spray adsorption and washing and moistening residue with used washing liq.

摘要

Purification of effluent gases contg. fly ash, gases such as SO2, HCl and HF, and volatile heavy metals esp. Hg, comprises spray absorption; sepn. of dry solids; at least two washing steps using recirculating washing liquid; and sepn. of wet solid and harmful material. The process is carried out under constant operating conditions by (a) removing part of the circulating washing liq. from each washing step and replacing it with fresh washing liq. or reagent; (b) vaporising the removed portion of washing liq. by spray absorption; and (c) moistening the residues from the spray absorption and the dry, separated solids. The residues (c) are moistened with liq. from the removed portion of wash liq. Pref. the residues are moistened to contain at least 10% (pref. 25-35%) moisture, and the wash liq. remaining after moistening the residues is evaporated by spray absorption. USE/ADVANTAGE - The process is used to clean the effluent from burning rubbish. It removes both dust and noxious gases, in dry and wet process steps, without producing used wash liq. requiring disposal, and without using fresh water for moistening the residues to make them easier to handle.