Procedures for the release and recovery of chlorine from a gas mixture containing chlorine, carbon dioxide, and gas not condensavel,And processes for removing chlorine from a gas mixture comprising chlorine gas and carbon dioxide gas

摘要

A gaseous mixture (531) containing chlorine, carbon dioxide and non-condensable gas is compressed (501) and cooled (502) to separate it (504) into a residual gas formed principally of a major portion of the non-condensable gas and a condensate formed primarily of chlorine. The condensate is fed to a stripping column (505) to desorb carbon dioxide and a minor portion of the non-condensable gas dissolved in the condensate. The stripped gas formed primarily of chlorine and carbon dioxide may be treated further. Namely, the stripped gas is mixed with the residual gas. At least a portion of the mixed gas is fed into an absorption column (512), whereby a major portion of remaining chlorine is absorbed to lower the chlorine content. Removal of chlorine from such a gaseous mixture or an off-gas from the above process can be achieved by washing it (525) with an aqueous solution or suspension containing an alkali metal sulfite and/or an alkaline earth metal sulfite while controlling the pH of the solution or suspension within a range of 1.9-6.3.