Argon recovery from argon-oxygen-decarburization process waste gases

Abstract

The present invention is directed to a method for recovering argon from a feed mixture comprising argon, carbon monoxide, carbon dioxide, nitrogen, and hydrogen which comprises the steps of (a) purifying the feed mixture to remove contaminants, (b) compressing the purified feed mixture to a separation pressure, and (c) passing the compressed purified feed mixture through a pressure swing adsorption system to separate carbon monoxide, carbon dioxide, and all or most of the nitrogen from the mixture as adsorbed products and to produce an argon-rich fraction as a non-adsorbed product. The argon-rich fraction from step (c) may be further purified by passing the fraction to a cryogenic fractional distillation system to separate hydrogen and any remaining nitrogen from the fraction as a distillate product and to produce a pure argon product. In a second and third embodiment, the invention is directed to a method for recovering argon from a feed mixture comprising argon, carbon monoxide, carbon dioxide, nitrogen, and oxygen, wherein oxygen is removed from the argon-rich fraction exiting the pressure swing adsorption system in step (c) by passing the fraction to a second pressure swing adsorption system before or after further purification of the fraction in a cryogenic fractional distillation system.