Patent ID: 8216351

Claim:
An apparatus for purifying a feed stream containing carbon dioxide to obtain a carbon dioxide product, said apparatus comprising: means for drying a feed stream having a super atmospheric pressure; a main heat exchanger connected to the drying means and configured to partially cool the feed stream after having been dried; a stripping column having contacting elements to contact a descending liquid phase with an ascending vapor phase within the stripping column to strip impurities from the descending liquid phase and thereby to produce a carbon dioxide-Jean column overhead and a carbon dioxide-rich, liquid column bottoms; a reboiler operatively associated with the stripping column to initiate the formation of the ascending vapor phase within the stripping column and connected to the main heat exchanger so that the stripping column is reboiled with the feed stream after having been partially cooled and the feed stream is further cooled within the reboiler; the main heat exchanger also connected to the reboiler and configured to at least partially liquefy the feed stream after the feed stream is further cooled within the reboiler; the stripping column in flow communication with the main heat exchanger such that the stripping column receives at least part of the feed stream after having been partially liquefied in the main heat exchanger and the descending liquid phase is thereby established within the stripping column; a feed stream expansion valve positioned between the main heat exchanger and the stripping column so that, prior to reception of the at least part of the feed stream into the stripping column, the feed stream is expanded to an operational pressure of the stripping column that is less than that of the feed stream, thereby to lower a reboiling temperature at which the stripping column reboils to a level that is below the feed stream temperature after having been partially cooled; means for recovering refrigeration in the main heat exchanger from a carbon dioxide-lean stream composed at least in part of a column overhead stream column made up of the carbon dioxide-lean column overhead of the stripping column; at least one product stream expansion valve connected to the stripping column for expanding a carbon dioxide product stream composed of the carbon dioxide-rich, liquid column bottoms of the stripping column; the main heat exchanger connected to the at least one product stream expansion valve and also configured to vaporize the carbon dioxide product stream; and a compressor connected to the main heat exchanger for compressing the carbon dioxide product stream to obtain a compressed carbon dioxide stream as at least part of the carbon dioxide product.