Sulfur recovery plant tail gas treatment process

A process for the removal of hydrogen sulfide from a gas stream, which comprises:

• (i) subjecting the hydrogen sulfide-containing gas to the Claus reaction to convert hydrogen sulfide to sulfur and form a tail gas stream comprising H2S and less than 2000 vppm SO2,
• (ii) cooling the tail gas stream by contact with a stream of water as a coolant,
• (iii) contacting the gas stream from step (ii) with a circulating stream of a dilute, absorbent solution of a severely sterically hindered aminoether alcohol to further cool the gas stream and to remove SO2 from the gas stream,
• (iv) contacting the gas stream from step (iii) with a stronger absorbent solution of a severely sterically hindered aminoether alcohol to remove H2S from the gas stream.

A process for the removal of hydrogen sulfide from a gas stream, which comprises:

• (i) subjecting the hydrogen sulfide-containing gas to the Claus reaction to convert hydrogen sulfide to sulfur and form a tail gas stream comprising H2S and less than 1000 vppm SO2 at a temperature of 130 to 150° C.,
• (ii) cooling the tail gas stream to a temperature of 40-60° C. by countercurrent direct contact with cooling water circulating in a quench column having a cooling water circulation loop,
• (iii) contacting the gas stream from step (ii) in countercurrent with a circulating stream of a dilute, absorbent solution of a severely sterically hindered secondary aminoether alcohol in a quench column having a circulation loop for the dilute absorbent solution to further cool the gas stream and remove SO2 from the gas stream, and separating the further cooled gas stream from the dilute absorbent solution,
• (iv) contacting the separated, cooled gas stream from step (iii) in countercurrent with a stronger circulating absorbent solution of a severely sterically hindered secondary aminoether alcohol in an absorber column having a circulation loop for the stronger circulating absorbent solution to remove H2S from the gas stream by absorption into the stronger absorbent solution to form a purified gas stream and separating the purified gas stream from the stronger absorbent solution,
• (v) regenerating the stronger absorbent solution by steam stripping in a regeneration zone.