VERFAHREN UND EINRICHTUNG ZUR KONTROLLE VON AMMONIAK-SCHLUPF IN DER REDUKTION VON SCHWEFELDIOXIDEMISSIONEN

摘要

A process is provided for removing sulfur dioxide out of gases by feeding the gases into a scrubber, where they are counter-currently contacted with a descending solution containing ammonium hydroxide and ammonium sulfate so that the sulfur dioxide is sorbed into the solution containing ammonium hydroxide and ammonium sulfate and a scrubbed gas is discharged from the scrubber. The sulfur dioxide-loaded solution is collected in a sump at the bottom of the scrubber, where a mixture of ammonia and air is injected into the sulfur dioxide loaded solution so that the ammonia reacts with the sulfur dioxide to produce ammonium sulfite which is (in turn) oxidized by the air into ammonium sulfate. The mixture of air and ammonia is injected into the solution in a direction that is towards the bottom of the sump so that portions of solution containing a higher pH and higher ammonium sulfite levels than the remainder of the solution is avoided, thereby minimizing ammonia slip out of the scrubber.