Belt sintering plant waste gas purificn. to reduce dioxin and furan concn. - by removing dust, moistening with aq. hydrogen peroxide and scrubbing, can operate at high temps. of over 250 deg.

摘要

Purificn. of the waste gas stream (I) from a belt sintering machine involves removing dust in an electrofilter. (I) on leaving the electrofilter is moistened with a finely-dispersed aq. treatment soln. (II) contg. H2O2, then passed to a gas scrubber with a spray electrode aggregate, passed through this aggregate without droplets and treated with a finely-dispersed liquor (III) in a subsequent scrubbing zone. Pref. (III) contains H2O2 and/or hypochlorite and/or finely ground activated charcoal or hearth furnace coke, pref. introduced by passing (III) through an activated charcoal filter or a bed of coke before it enters the scrubber. Before the spray electrode aggregate, (I) is moistened until satd. and adjusted to a H2O2 concn. of 50-150 mg/Ncu.m (I). Before entering the electrofilter, (I) is treated with aminoalcohols and/or alkylamines pref. ethanolamine and/or ethylamine and/or with NH3. USE/ADVANTAGE - The concn. of chlorinated hydrocarbons, esp. dioxins and furans in (I) is reduced and the electrofilter can operate at high temps., of over 250 deg.C without increasing the concn. of highly toxic polychlorinated dibenzofurans.