| 摘要 |
A system and method for capturing and separating carbon dioxide from mixed gas streams. The gas stream is processed in a structure including a compression module comprising a plurality of compressors, intercoolers and inter-stage condensate separators. The flow path from the compression module includes a plurality of flow separators, gas stream splitters, heat exchangers and at least a first mixer and a first expander. The gas stream is sequentially compressed and cooled to form process condensate and separate it from the compressed gas stream. The gas stream is further dried and cooled to liquefy carbon dioxide and separate it from the non-condensable portion. Selective expansion of liquid carbon dioxide streams provides cooling for the system, and further energy efficiency is achieved by selective recycling of portions of gas streams, allowing for compact equipment and economical operation, while providing for high purity product streams of carbon dioxide. |
| 主权项 |
1. A method for separating carbon dioxide from a mixed gas stream, the method comprising the steps of:
(a) providing a processing structure including a compression module comprising at least a plurality of compressors, a plurality of intercoolers with inter-stage condensate separators, the processing structure further including a plurality of flow separators, a plurality of gas stream splitters, a plurality of heat exchangers, a plurality of mixers, at least a first expander, and a single throttle valve; (b) delivering the mixed gas stream to the compression module, and optionally pre-treating the mixed gas stream by removing at least one of water, particulate matter, mercury and other heavy metals, hydrogen chloride, hydrogen fluoride, nitrogen oxides, sulphur oxides and other sulphur derivatives from the mixed gas stream; (c) compressing and cooling the mixed gas stream through each of the plurality of compressors and intercoolers in sequence to form a compressed gas stream and passing the compressed gas stream in sequence through ones of the plurality of heat exchangers to generate an output stream including liquid carbon dioxide and a gaseous stream; (d) selectively removing the liquid carbon dioxide from the output stream in selected ones of the plurality of flow separators to generate from each selected flow separator a liquid carbon dioxide stream and a separated gaseous stream; (e) selectively mixing in the first mixer at least two of the liquid carbon dioxide streams generated in step (d) to form a first mixed liquid carbon dioxide stream and sending the mixed liquid carbon dioxide stream to a second mixer to form the second mixed liquid carbon dioxide stream; (f) throttling the second mixed liquid carbon dioxide stream from step (e); (g) passing at least a portion of the throttled second mixed liquid carbon dioxide stream from step (f) through one of the heat exchangers to form a carbon dioxide product stream and removing the said carbon dioxide product stream from the processing structure; (h) splitting a selected one of the separated gaseous streams in one of the plurality of gas stream splitters and using the other separated gaseous stream to further cool the compressed gas stream and the split stream and additionally using the other separated gaseous stream to still further cool the compressed gas stream to form liquid carbon dioxide and separating in selected ones of the plurality of flow separators the liquid carbon dioxide from other gases and selectively removing the other gases from the processing structure; (i) selectively recycling the separated gaseous stream from at least one of the flow separators to at least one of the compressors selected from a second compressor and a subsequent compressor in the sequence in the compression module; and (j) selectively expanding in the first expander a split stream from the selected splitter in step (h), to recover energy and to provide cooling to the processing structure; |
