Method and apparatus for removing carbonyl sulfide from a gas stream via wet scrubbing

Abstract

Methods for removing carbonyl sulfide (COS) from a synthesis gas stream are disclosed. The method entails raising the water level of a wet scrubber so that hydrolysis of the COS may occur in the scrubber itself instead of a COS reduction chamber and no additional catalysts other than those naturally occurring in the production of the synthesis gas need be introduced into the scrubber. The water is raised, in one example, to a level such that water within an inner tube of the wet scrubber flows over an upper end of the inner tube. Raising the water level in the scrubber ensures intimate and vigorous interaction between the water, the COS, and the naturally occurring catalyst, and promotes the hydrolysis of the COS. In one example, the naturally occurring catalyst (e.g., alumina oxide) is present in the coal ash produced when coal is the fuel gasified that creates the synthesis gas stream.