Process for the simultaneous absorption of sulfur oxides and production of ammonium sulfate

摘要

Process for the removal of sulfur oxides from sulfur oxide-containing gas with simultaneous production of ammonium sulfate. The process is carried out by first passing hot sulfur oxide-containing gas through a prescrubber wherein the gas contacts saturated aqueous ammonium sulfate liquor which is recycled in the prescrubber, followed by passing the prescrubbed gas through an absorber wherein the prescrubbed gas contacts dilute aqueous ammonium sulfate liquor. The sulfur oxide in the sulfur oxide-containing gas is absorbed by the dilute aqueous ammonium sulfate liquor in the absorber, and scrubbed gas is removed from the absorber. The dilute aqueous ammonium sulfate liquor is treated with ammonia and air and the absorbed sulfur dioxide is converted to ammonium sulfate in the liquor. The dilute ammonium sulfate liquor is recycled into contact with the prescrubbed gas in the absorber. Dilute aqueous ammonium sulfate liquor is removed from the absorber and added to the saturated aqueous ammonium sulfate liquor in the prescrubber where it becomes saturated due to evaporation caused by the hot gas. Ammonium sulfate crystals form in the saturated aqueous ammonium sulfate liquor in the prescrubber are recovered as product from saturated aqueous ammonium sulfate withdrawn from the prescrubber.