Desulfurizing of reducing gas stream using a recycle calcium oxide system

摘要

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 CO2, H2O and O2 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.