Continuous carbonyl sulphide removal from gas - by closed cycle hydrolysis with aq. alkanolamine to form hydrogen sulphide and carbon di:oxide

摘要

Continuous COS removal from gas streams comprises (a) contacting the gas stream with an aq. alkanolamine hydrolysis medium, (A), flowing in a closed hydrolysis zone cycle at a temp. enabling COS hydrolysis with H2O into H2S and CO2; (b) the H2S- and CO2-contg. effluent gas stream, obtd. is contacted with a fresh absorbent for acid gas, at least for H2S, in an absorption zone, to remove H2S. Continuous process for treating COS- and H2S-contg. gas streams comprises (a) contacting the gas stream with an aq. absorbent for at least H2S in a 1st absorption zone, to strip off H2S, (b) contacting the 1st residual gas stream with (A) in hydrolysis zone, to hydrolyse COS with water and (c) contacting the 2nd residual gas stream, contg. H2S and CO2, with fresh absorbent for acid gas, at least H2S in a 2nd absorption zone. The treated gas stream can be natural gas. Closed cycle hydrolysis step increases desulphurisation and completely removes COS.