US 6,719,957 B2Granted

Process for purification of anhydrous hydrogen chloride gas

AssigneeBayer Aktiengesellschaft

InventorsBill L. Brady, Jr., Guenther Weymans, Berthold Keggenhoff, Friedhelm Steffens

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Abstract

High boiling contaminants such as chloro-aromatic compounds are removed from a gas by compressing the gas containing the contaminant, cooling the compressed gas to reduce the temperature of the gas to at least 20° C. above the outlet temperature of a second cooling stage but above the freezing point of the highest melting compound in the first cooling stage, further cooling the gas in a second cooling stage to at least −20° C., returning cooled gas from the second cooling stage to the first cooling stage, and recovering condensate streams which contain the contaminant compound from the first and second cooling stages. An apparatus suitable for carrying out this process is also disclosed. The process of the present invention is particularly useful for removing chloro-aromatic compounds from anhydrous hydrogen chloride gas.

Claims14

Dependent claims

A process for the purification of hydrogen chloride gas containing contaminants having a boiling point higher than 100° C. comprising

a) compressing hydrogen chloride gas containing a contaminant,
b) feeding the compressed hydrogen chloride gas to a first cooling stage in which the temperature of the compressed gas is reduced to at least 20° C. above that of a second cooling stage, thereby generating a first condensate stream and a cooled hydrogen chloride gas stream,
c) feeding the cooled hydrogen chloride gas stream from the first cooling stage to a second cooling stage in which the temperature of the feed is reduced to at least −20° C., thereby generating a second condensate stream and a second cooled hydrogen chloride gas stream,
d) returning the second cooled hydrogen chloride gas stream to the first cooling stage as cooling medium, and
e) removing the first and second condensate streams.

2 more elements

Dependencies are inferred from the claim text.