| 主权项 |
1. A refining system (100; 100A; 100B; 100C; 100D; 100E) for refining a feed gas stream (10) comprising volatile hydrocarbons as a first component, carbon-dioxide as a second component and water vapour, the volatile hydrocarbons having a lower dew point temperature than the carbon dioxide, the refining system comprising:
an input section (105) for input of the feed gas stream (10), the input section comprising a dehydration unit for dehydrating the feed gas stream, capable of obtaining a water dew point of the feed gas stream between −45° C. and −65° C.; a pre-cooling section (110) coupled to the input section (105) for receiving the dehydrated feed gas stream, the pre-cooling section being configured for (i) pre-cooling the received dehydrated feed gas stream below a dew point of a part of the received dehydrated feed gas to form a pre-cooled dehydrated feed gas comprising a liquid enriched with carbon dioxide and a gas enriched with volatile hydrocarbons, and (ii) separating liquid components comprising a first portion of the liquid enriched with carbon dioxide and a pre-cooled mixed stream comprising a remaining portion of the liquid enriched with carbon dioxide and the gas enriched with volatile hydrocarbons from the pre-cooled dehydrated feed gas; a fractionation section (115) coupled to the pre-cooling section (110) for receiving the pre-cooled mixed stream, the fractionation section being configured for fractionating the pre-cooled mixed stream into a first fractionated stream of gas enriched with volatile hydrocarbons at a first separation outlet and a second fractionated stream of a liquid enriched with carbon dioxide at a second separation outlet, the fractionation section (115) comprising:
a heat exchanger (234) configured for cooling the first fractionated gas stream and for receiving a liquid carbon dioxide enriched stream formed in the pre-cooling section (110) as a coolant to cool the first fractionated gas stream as to form a cooled first fractionated gas stream comprising a liquid fraction enriched with carbon dioxide and a gas enriched with volatile hydrocarbons, the heat exchanger having an outlet for releasing the cooled first fractionated gas stream, anda fractionation separator vessel (232) being configured for separating the carbon dioxide enriched liquid of the cooled first fractioned gas stream via a bottom outlet of said vessel and the gas enriched with volatile hydrocarbons of the cooled first fractionated gas stream via a top outlet of said vessel; an expansion cooling and separation section (120) coupled to the fractionation section (115) for receiving the gas enriched with volatile hydrocarbons of the cooled first fractionated gas stream, the expansion cooling and separation section comprising:
a supersonic cyclonic separator (240), being configured for:(a) at an inlet receiving the gas enriched with volatile hydrocarbons of the cooled first fractionated gas stream, from the fractionation separator vessel (232),(b) expanding the gas enriched with volatile hydrocarbons of the cooled first fractionated gas stream, thereby further cooling the gas enriched with volatile hydrocarbons of the cooled first fractionated gas stream to a temperature and pressure below the dew point of the gas at which a supercooled carbon dioxide liquid is formed and forming a supercooled first fractionated gas stream,(c) separating said supercooled first fractionated gas stream into a cooled low density fluid fraction, which is enriched with volatile hydrocarbons, and a supercooled high density fluid fraction which is enriched with carbon dioxide and volatile hydrocarbons depleted, and(d) creating a first flow of the cooled low density fluid fraction at a first flow outlet (22) and a second flow of the supercooled high density fluid fraction enriched with carbon dioxide at a second flow outlet, anda crystallization separator vessel (242) coupled to the second outlet of the supersonic cyclonic separator (240) and being configured for:(a) receiving the second flow of the supercooled high density fluid fraction from the supersonic cyclonic separator (240),(b) solidifying the carbon dioxide component of the supercooled high density fluid fraction,(c) separating the solidified fraction and liquid fraction from the supercooled high density gas fluid fraction, and(d) melting the solidified fraction in a bottom section of the crystallization separator vessel to form a carbon dioxide enriched liquid the crystallization separator vessel having a top outlet coupled to the first flow outlet of the supersonic cyclonic separator (240) for producing a carbon dioxide depleted gas stream and a bottom outlet for the carbon dioxide enriched liquid formed in the bottom section that is coupled to the fractionation section (115) via a reflux conduit (24) so that the carbon dioxide enriched liquid from the crystallization separator vessel is refluxed to the fractionation section (115). |
