Sulfur recovery operation with improved carbon dioxide recovery

A process for recovering sulfur and carbon dioxide from a sour gas stream, the process comprising the steps of:

• providing a sour gas stream to a selective amine absorption unit, the sour gas stream comprising hydrogen sulfide and carbon dioxide;
• separating the hydrogen sulfide from the carbon dioxide in the selective amine absorption unit to produce an enriched carbon dioxide stream and enriched hydrogen sulfide stream, wherein the enriched carbon dioxide stream comprises carbon dioxide;
• introducing the enriched hydrogen sulfide stream to a membrane separation unit, wherein the enriched hydrogen sulfide stream comprises hydrogen sulfide and carbon dioxide;
• separating the hydrogen sulfide from the carbon dioxide of the enriched hydrogen sulfide stream in the membrane separation unit to produce a retentate stream and a permeate stream;
• introducing the retentate stream to a sulfur recovery unit, wherein the retentate stream comprises hydrogen sulfide;
• processing the retentate stream in the sulfur recovery unit to produce a sulfur stream and a tail gas stream, wherein the sulfur stream comprises liquid sulfur;
• and
• recycling the permeate stream to the amine absorption unit.

A process for recovering sulfur and carbon dioxide from two sour gas streams, a first sour gas stream having concentrations of carbon dioxide and hydrogen sulfide greater than 10 mol % and a concentration of nitrogen less than 10 mol %, and a second sour gas stream having concentrations of carbon dioxide and hydrogen sulfide less than 20 mol % or a concentration of nitrogen greater than 10 mol %, the process comprising the steps of:

• introducing the first sour gas stream to a membrane separation unit and separating the first sour gas stream to obtain a retentate stream and a permeate stream, the retentate stream comprising hydrogen sulfide and the permeate stream comprising carbon dioxide;
• introducing the permeate stream and the second sour gas stream to a selective amine absorption unit and using an amine absorption process to obtain a recovered hydrogen sulfide stream and an enriched carbon dioxide stream, the recovered hydrogen sulfide stream comprising hydrogen sulfide and the enriched carbon dioxide stream comprising carbon dioxide;
• recycling the recovered hydrogen sulfide stream to the membrane separation unit;
• and
• introducing the retentate stream to a sulfur recovery unit and processing the retentate stream using the Claus process to obtain a sulfur stream comprising sulfur.