Hydrogen chloride removal from (domestic) waste combustion gas - by spraying hot gas with aq. alkaline soln. or suspension without excessive cooling

摘要

Removal of HCl from exhaust gas from the combustion of waste is effected by absorption with alkali. The gas at 200-330 degrees C is passed into a chamber, in which it is sprayed with an aq. soln. or alkali metal carbonate or an aq. suspension of Ca(OH)2, CaCO3 or MgO. The amt. of soln)suspension used is such that the temp. of the gas leaving the chamber is over 125 degrees C, whilst the material formed by drying of the sprayed soln./suspension is discharged as a dry, free-running powder. The process is used in the purificn. of exhaust gas from the combustion of domestic refuse, the HCL being formed from chlorinated plastics, esp. PVC. The gas is not cooled strongly and the absorbent is almost completely utilised, so that recirculation is unnecessary. Only a very slight pressure drop occurs. The HCl content is reduced to a very low value and the process does not interfere with the use of electrofilters of the plate type.