A CO2 separation and liquefaction system such as might be used in a carbon capture and sequestration system for a fossil fuel burning power plant is disclosed. The CO2 separation and liquefaction system includes a first cooling stage to cool flue gas with liquid CO2, a compression stage coupled to the first cooling stage to compress the cooled flue gas, a second cooling stage coupled to the compression stage and the first cooling stage to cool the compressed flue gas with a CO2 melt and provide the liquid CO2 to the first cooling stage, and an expansion stage coupled to the second cooling stage to extract solid CO2 from the flue gas that melts in the second cooling stage to provide the liquid CO2.

The present disclosure provides systems and methods useful in capture of one more moieties (e.g., carbon dioxide) from a gas stream (i.e., direct air capture). In various embodiments, the systems and methods can utilize at least a scrubbing unit, a regeneration unit, and an electrolysis unit whereby an alkali solution can be used to strip the moiety (e.g., carbon dioxide) from the gas stream, the removed moiety can be regenerated and optionally purified for capture or other use, and a formed salt can be subjected to electrolysis to recycle the alkali solution back to the scrubber for re-use with simultaneous production of one or more further chemicals.

Methods and systems for separating a desublimatable compound from hydrocarbons is disclosed. A feed fluid stream, consisting of a hydrocarbon and a desublimatable compound, is passed into an upper chamber of a vessel. The feed fluid stream is cooled in the upper chamber, thereby desublimating a portion of the desublimatable compound out of the feed liquid stream to form a product gas stream and a desublimatable compound snow which is collected in the lower chamber of the vessel. A lower portion of the desublimatable compound snow is melted to form a liquid desublimatable compound stream such that an upper portion of the solid desublimatable compound snow remains as an insulative barrier between the upper chamber and the liquid desublimatable compound stream. The liquid desublimatable compound stream is removed at a rate that matches a production rate of the solid desublimatable compound snow, thereby maintaining the insulative barrier.

A process and apparatus for producing a hydrogen-enriched product and recovering CO.sub.2 from an effluent stream from a hydrogen production process unit are described. The process utilizes a CO.sub.2 recovery system integrated with a PSA system that produces at least two product streams to recover additional hydrogen and CO.sub.2 from the tail gas stream of a hydrogen PSA unit in the hydrogen production process.

A process and apparatus for producing a hydrogen-enriched product and recovering CO.sub.2 from an effluent stream from a hydrogen production unit are described. The effluent from the hydrogen production unit, which comprises a mixture of gases comprising hydrogen, carbon dioxide, water, and at least one of methane, carbon monoxide, nitrogen, and argon, is sent to a PSA system that produces at least two product streams for separation. The PSA system that produces at least two product streams separates the gas mixture into a high-pressure hydrogen stream enriched in hydrogen, optionally a second gas stream containing the majority of the impurities, and a low-pressure tail gas stream enriched in CO.sub.2 and some impurities. The CO.sub.2-rich tail gas stream is compressed and sent to a CO.sub.2 recovery unit, where a CO.sub.2-enriched stream is recovered. The CO.sub.2-depleted overhead gas stream is recycled to the PSA system that produces at least two product streams.

A gas separation and utilization method includes the steps of: (a) providing an ascending flow of a liquid containing carbon dioxide gas and methane gas; (b) extracting at least a fraction of the methane gas from the liquid to provide a methane enriched gas; (c) extracting at least a fraction of the carbon dioxide gas from the liquid to provide a carbon dioxide enriched gas, which is extracted from the ascending flow of the liquid downstream of the methane enriched gas; (d) collecting the methane enriched gas; (e) feeding the carbon dioxide enriched gas as a fuel into an oxyfuel power generation system; (f) generating power from the oxyfuel power generation system; and (g) expelling an exhaust from the oxyfuel power generation system, wherein the exhaust comprises carbon dioxide and water vapor. A system configured to perform the method and a grid balancing method using the system are also disclosed.

Process for extracting nitrogen from a feed stream of natural gas or of biomethane comprising at least nitrogen, methane, CO.sub.2 and/or H.sub.2S, wherein a liquid stream enriched in methane resulting from a cryogenic separation is recovered by pumping the bottom product of one or more of the columns and/or pumping a liquid stream to a pressure P2 greater than 25 bar absolute and preferably greater than the critical pressure of said product.

A cryogenic distillation tower for separating a feed stream. The tower includes a distillation section. A controlled freeze zone section is situated above the distillation section and forms a solid from the feed stream. The controlled freeze zone section includes a spray assembly in an upper section and a melt tray assembly in a lower section. The melt tray assembly includes at least one vapor stream riser that directs the vapor from the distillation section into liquid retained by the melt tray assembly, and one or more draw-off openings positioned to permit a portion of the liquid to exit the controlled freeze zone section. The portion of the liquid indirectly exchanges heat with a heating fluid. One or more return inlets return the portion of the liquid to the melt tray assembly after it has been heated in the heat exchanger.

A system for processing an LNG feed, the system comprising: a bulk removal stage arranged to remove and release CO.sub.2 liquid from the inflow feed, said bulk removal stage including a first HGMT device, and; a polishing stage arranged to receive a lean CO.sub.2 feed from the first HGMT device, said polishing stage arranged to remove and release residual CO.sub.2, the polishing stage including a second HGMT device; wherein the polishing stage is arranged to release an outflow of CO.sub.2 stripped LNG.

A solid handling vessel comprising: a separation tank having an inlet for tangentially receiving an inflow of CO.sub.2 enriched hydrocarbon feed stream; said separation tank to facilitate cyclonical flow of said feed stream; a heating assembly within the separation tank for maintaining the feed stream above a temperature for solidification of CO.sub.2; a gas outlet arranged to vent gas from the separation tank; a collection tank located below, and in fluid communication with, the separation tank, said collection tank arranged to receive separated liquid and outflow said liquid from a liquid outlet.