Purification of carbon dioxide

摘要

Impure carbon dioxide (“CO2”) comprising a first contaminant selected from the group consisting of oxygen (“O2”) and carbon monoxide (“CO”) is purified by separating expanded impure carbon dioxide liquid in a mass transfer separation column system. The impure carbon dioxide may be derived from, for example, flue gas from an oxyfuel combustion process or waste gas from a hydrogen (“H2”) PSA system.

主权项

1. Apparatus for purifying impure carbon dioxide comprising a first contaminant selected from the group consisting of oxygen and carbon monoxide said apparatus comprising:
a first compressor arrangement for compressing impure carbon dioxide gas to produce compressed impure carbon dioxide gas; a condenser arrangement for condensing compressed impure carbon dioxide gas to produce impure carbon dioxide liquid; a conduit arrangement for feeding compressed impure carbon dioxide gas from said first compressor arrangement to said condenser arrangement; a heat exchanger arrangement for cooling impure carbon dioxide liquid by indirect heat exchange to produce cooled impure carbon dioxide liquid, said heat exchanger arrangement comprising at least one fluid passage; a conduit arrangement for feeding impure carbon dioxide liquid from said condenser arrangement to said fluid passage(s) of said heat exchanger arrangement; a first pressure reduction arrangement for expanding impure carbon dioxide liquid to produce expanded impure carbon dioxide liquid; a conduit arrangement for feeding cooled impure carbon dioxide liquid from said fluid passage(s) in said heat exchanger arrangement to said first pressure reduction arrangement; a mass transfer separation column system for separating expanded impure carbon dioxide liquid to produce first contaminant-enriched overhead vapor and carbon dioxide bottoms liquid; a conduit arrangement for feeding expanded impure carbon dioxide liquid from said first pressure reduction arrangement to said column system; a reboiler for reboiling carbon dioxide bottoms liquid by indirect heat exchanger against crude carbon dioxide gas to produce carbon dioxide vapor for the column system and cooled crude carbon dioxide gas; a conduit arrangement for feeding first contaminant-enriched overhead vapor from said column system to said heat exchanger arrangement for warming to produce first contaminant-enriched gas; a conduit arrangement for combining first contaminant-enriched gas from said heat exchanger arrangement with contaminated carbon dioxide gas to form crude carbon dioxide gas and for feeding at least a portion of said crude carbon dioxide aas to said reboiler; a conduit arrangement for feeding cooled crude carbon dioxide gas from said reboiler to said heat exchanger arrangement for further cooling to produce partially condensed crude carbon dioxide fluid; a phase separator for phase separating partially condensed crude carbon dioxide fluid into first impure liquid carbon dioxide and carbon dioxide-depleted vapor; a conduit arrangement for feeding partially condensed crude carbon dioxide fluid from said heat exchanger arrangement to said phase separator; a second pressure reduction arrangement for expanding first impure liquid carbon dioxide to produce expanded first impure liquid carbon dioxide at a first pressure; a conduit arrangement for feeding first impure liquid carbon dioxide from said phase separator to said second pressure reduction arrangement; a conduit arrangement for feeding expanded first impure liquid carbon dioxide from the second pressure reduction arrangement to said heat exchanger arrangement for vaporization to provide refrigeration for the method and first impure gaseous carbon dioxide; and a conduit arrangement for feeding first impure gaseous carbon dioxide from said heat exchanger arrangement to said first compressor arrangement.