Abstract: The effluent streams from utility stack gases containing nitric oxides and sulfur dioxide are sequentially oxidized, absorbed with effluent spent alkylation acid, the unabsorbed remaining gases contacted with carbon monoxide from alkylation units in refinery cracking and other industrial plants to form sulfur, carbon dioxide and nitrogen, the carbon dioxide and nitrogen being vented, the sulfur oxidized to sulfur trioxide and contacting aqueous sulfuric acid therewith to effect concentration of said acid and suitability for recycle to an alkylation unit; the absorbate containing spent alkylation acid sequentially treated with a burning, oxidation, aqueous dilution and carbon monoxide treatment steps to form sulfuric acid for recycle to an alkylation unit and venting formed carbon dioxide and nitrogen.

Abstract: The effluent streams from utility stack gases containing nitric oxides and sulfur dioxide are entrained with sulfuric acid and carbon monoxide from refinery cracking and other industrial plants and in a sequence of separation and reaction steps nitrogen and carbon dioxide are vented to the atmosphere and regenerated concentrated sulfuric acid and sulfur produced.