TREATMENT OF SOUR GASES TO CONCENTRATE H2S FOR CLAUS PROCESS BY RECYCLING AMINE ABSORBENT

摘要

Sour industrial gases containing carbon dioxide and hydrogen sulfide are treated with amines to remove the CO2 and H2S. The amine absorbent containing or loaded with H2S and CO2 is regenerated and the off-gas containing concentrated amounts of H2S and CO2 is treated in a second amine absorber to produce an amine absorbent loaded with H2S. This amine is then regenerated to provide an off-gas containing a high ratio of H2S to CO2 which makes it suitable for use as the feed gas to a sulfur recovery unit such as a Claus plant. The process is automatically controlled so that the concentration of H2S in the second amine absorber is built up to and controlled at a desired set point so that the off-gas has the required H2S/CO2 ratio.