Catalyst added to Claus furnace reduces sulfur losses

Several substances effectively catalyze the reduction of carbon disulfide in Claus gas streams at Claus reaction furnace conditions (about 1,000{sup 0}C). Some conversion of carbonyl sulfide also occurs. Carbon disulfide and carbonyl sulfide as well-known problem compounds that reduce sulfur recovery efficiency in many sulfur recovery plants. Installation of a suitable catalytic material in the reaction furnace promises significant improvement of Claus plant efficiency, and prolonged life of the catalytic converters. Almost every Claus sulfur recovery plant makes some carbon disulfide (CS/sub 2/) and carbonyl sulfide (COS) in the reaction furnace, and in many of these plants, these compounds constitute a significant problem. CS/sub 2/ and COS often comprise more than 50% of sulfur losses in the tail gas. This article reexamines the issue of CS/sub 2/ and COS in the Claus plant. The relative importance of these two troublesome components is explored with data accumulated from Shell Canada Claus plants. The authors discuss which factors tend to produce these components. Then a method for reducing CS/sub 2/ and COS virtually at the source will be introduced.