| 摘要 |
<p>A method for removing contaminants from a gaseous or liquid stream (f) substantially comprising carbon dioxide comprises a purification step in a column having a top, bottom and an intermediate section. The purification step provides a contaminant lean stream (g2) leaving the top section of the column and a contaminant rich liquid stream (l2) leaving, optionally the bottom section of, the column. The containment rich liquid stream is fed to a reboiler (A3). The contaminant lean stream leaving the top section of the column is further subjected to a series of steps selected from two options. The first option (see figure 1) includes compressing the contaminant lean stream providing a compressed gaseous stream (g4), cooling the compressed gaseous stream in the reboiler providing at least a product stream (p) and a gaseous stream (g3), and feeding the gaseous stream to the column at the bottom section of the column. The second option (see figure 2) includes cooling the contaminant lean stream in the reboiler providing at least a product stream and a gaseous stream, compressing the gaseous stream providing a cooled compressed gaseous stream (g4’), and feeding the cooled compressed gaseous stream to the column at the bottom section of the column and depressurising the contaminant rich liquid stream leaving the bottom section of the column before entering the reboiler. The purification step may be selected from absorption using an absorbent when the feed stream is gaseous, and rectification having a liquid phase, when the feed stream is liquid, wherein the absorbent and liquid phase is liquid carbon dioxide.</p> |
