Process for releasing ammonia bound in coal water

Abstract

A process for releasing ammonia which is bound in coal water using a pre-desulfurization plant having ammonia and hydrogen sulfide scrubbers through which crude coking plant gas is passed comprises circulating the crude coke oven gases through the hydrogen sulfide scrubber and the ammonia scrubber in succession, directing the coal water first through the ammonia scrubber while the crude coking plant gases are being also circulated therethrough after passing it first through the hydrogen sulfide scrubber. An alkali solution is also circulated through the ammonia scrubber to enrich the solution with acid components and to liberate ammonia bound in the coal water directing the coal water which has been enriched from the ammonia scrubber into the hydrogen sulfide scrubber. The process is characterized by the fact that the alkali solution which has first served for the hydrogen sulfide scrubber is added to the ammonia hydrogen sulfide scrubber. 80 to 90% of the total alkali solution is charged to the hydrogen sulfide after-washery and then on the hydrogen sulfide pre-washery and the rest is charged to an ammonia expulsion apparatus.