United States Steel Corporation

Joseph E McGreal

Jerome Feinman

John L Howell

Edward J Nemeth

Stephen Waslo

A process for producing a low-sulfur content hot reducing gas stream comprising (a) contacting a sulfur bearing hot reducing gas stream with a desulfurizing agent comprising a desulfurizing fixed bed of solid particles comprising calcium oxide to thereby produce a low-sulfur content hot reducing gas stream and a calcium sulfide composition, then (b) contacting said calcium sulfide composition with an oxidizing gas composed of CO.sub.2, H.sub.2 O and O.sub.2 to thereby convert the sulfide of the composition to a regenerated calcium oxide, and sulfur dioxide and then (c) reusing the regenerated calcium oxide in step (a) to desulfurize a hot reducing gas, and further involving the improvement comprising avoiding the formation of calcium sulfate when regenerating said calcium sulfide composition by means of (a) a separate clean-up bed after the desulfurizing bed of step (a) to assure complete conversion of the calcium oxide to calcium sulfide in the desulfurizing bed, or (b) passing the oxidizing gas through the partially sulfided desulfurizing bed from a direction which minimizes the contact of any sulfur dioxide formed in the regeneration step with any unsulfided calcium oxide.

Desulfurizing of reducing gas stream using a recycle calcium oxide system

A process and apparatus for producing a low sulfur content, hot reducing gas by desulfurizing hot reducing gas by contacting the sulfur-bearing hot reducing gas with a bed of a particulate calcium oxide desulfurizing agent to thereby produce a product gas stream and a byproduct calcium sulfide composition, and then recovering sulfur from the calcium sulfide composition by contacting the calcium sulfide composition with hot liquid water at a temperature and corresponding pressure sufficient to maintain steam in the system and to thereby convert the sulfide to calcium hydroxide and hydrogen sulfide and to produce a liquid water stream containing sulfur, and then combining the sulfur-containing water stream with a fresh water stream and recycling this water stream for contacting the calcium sulfide composition. Preferably water vapor produced in the contacting step is condensed and returned to the system in the final stage of contacting the calcium sulfide composition with hot liquid water.

Low sulfur content hot reducing gas production using calcium oxide

Dolomite which has been used to remove sulfur and/or sulfur-containing compounds from gases by chemical reactions therewith is regenerated by passing through the spent dolomite an oxidizing gas selected from oxygen, CO.sub.2 and H.sub.2 O at temperatures between about 1500.degree. F. and the temperature at which the dolomite becomes unreactive.

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Penn Hills Township, PA, United States of America

Joseph E McGreal