Patent ID: 8557206

Claim:
A method of desulfurizing an oxygen-containing waste gas, comprising: providing from a waste gas source a waste gas that includes sulfur dioxide and oxygen; combining the waste gas with a first portion of a recycled stream of hydrogen sulfide in an amount sufficient to deplete the waste gas from oxygen in a catalytic reaction in which the hydrogen sulfide is oxidized to sulfur dioxide to thereby form an oxygen-depleted gas; and reacting the oxygen-depleted gas with at least one of externally added hydrogen and externally added carbon monoxide to reduce the sulfur dioxide to hydrogen sulfide to thereby form a reduced oxygen-depleted gas comprising hydrogen sulfide; using a second portion of the recycled stream to control effluent temperature of the second reactor; using at least a portion of the hydrogen sulfide from the reduced oxygen-depleted gas as the recycled stream; wherein the recycled stream is formed from the reduced oxygen-depleted gas comprising hydrogen sulfide and an absorber overhead product; and adjusting a ratio of the reduced oxygen-depleted gas comprising hydrogen sulfide and the absorber overhead product to thereby provide hydrogen sulfide to the catalytic reaction in a quantity sufficient for the oxygen contained in the waste gas to be consumed by the catalytic reaction.