METHOD FOR RECOVERING HYDROGEN SULFIDE IN GAS AT HIGH CONCENTRATION AND APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To obtain sulfur, sulfurous acid, sulfuric acid or gypsum by bringing CO2 - and H2 S-contg. gas to be treated into contact with an absorbing soln., discharging part of CO2 from the soln. contg. absorbed SO2 and H2 S, recovering a gaseous mixture of H2 S having a specified concn. with CO2 and partially oxidizing or burning the gaseous mixture. SOLUTION: Gas to be treated is fed into a CO2 and H2 S removing tower 2, where it is brought into contact with 45% aq. soln. of N-methyldiethanolamine as an absorbing soln fed by 0.21 per 1Nm3 of the gas to absorb CO2 and H2 S in the soln. Part of the absorbed CO2 is discharged from the soln. in a separation drum 6 and the discharged CO2 is compressed by a compressor 14 and circulated to a line 1 for feeding gas to be treated. The absorbing soln. is then heated in an absorbing soln. regenerating tower 9 and a gaseous mixture of =13vol.% H2 S with CO2 is recovered. Air is added to the gaseous mixture and they are burned and absorbed in an aq. suspension of calcium carbonate to obtain gypsum.