Sulphur cpds. removal from Claus sulphur recovery unit

摘要

Process for the removal of sulphur cpds. from the off-gas of a sulphur recovery unit of the Claus type, comprises (a) mixing the off-gas and a gas having a higher content of hydrogen sulphide than the off-gas to form a gas mixt. having an increased hydrogen sulphide to sulphur dioxide molar ratio compared to the off-gas, padding the mixt. thus formed at a temp. below 300 deg.C over a catalyst promoting the Claus reaction, and sepg. the second off-gas from the catalyst; (b) passing the second off-gas over a regenerable, solid metal oxide absorbent to absorb hydrogen sulphide with formation of a spent metal oxide absorbent and sepg. the unabsorbed portion of the second off-gas from the spent metal oxide absorbent; (c) regenerating the spent metal oxide absorbent, thereby producing regenerated absorbent and a gas rich in sulphur cpds.; and (d) reusing the step (b) the regenerated absorbent obtd. in step (c) for further hydrogen sulphide absorption and introducing the gas rich in sulphur cpds. produced in step (c) into a sulphur recovery unit of the Claus type.