Abstract: In a system for air fractionation by low-temperature rectification, refrigeration is produced in a cooling stage by compression and expansion of the feed air or of nitrogen from rectification. By using the work gained during expansion for compressing only a partial stream of the gas passed through the cooling stage, the system according to this invention operates with increased efficiency and lower operating costs.
Type:
Grant
Filed:
November 14, 1988
Date of Patent:
November 28, 1989
Assignee:
Linde Akitengesellschaft
Inventors:
Werner Skolaude, Gunnar Eggendorfer, Horst Corduan
Abstract: A process is disclosed for the purification of a gaseous stream contaminated at least with CO.sub.2 and H.sub.2 S. The gaseous stream is preheated and subjected, in the presence of recycled SO.sub.2, to a catalytic conversion of H.sub.2 S into elemental sulfur. The thus-obtained sulfur is separated, and the residual gas, which contains at least H.sub.2 S, SO.sub.2, CO.sub.2, and water, is freed absorptively from SO.sub.2 after oxidative conversion of H.sub.2 S to SO.sub.2. It is proposed that the residual gas, after oxidative conversion of H.sub.2 S to SO.sub.2, is cooled in heat exchangers, preferably regenerators, and is subsequently scrubbed with a solvent consisting predominantly of tetraethylene glycol dimethyl ether.