A method and apparatus for liquefying a feed gas stream comprising natural gas and carbon dioxide. A method includes compressing an input fluid stream to generate a first intermediary fluid stream; cooling the first intermediary fluid stream with a first heat exchanger to generate a second intermediary fluid stream, wherein a temperature of the second intermediary fluid stream is higher than a carbon dioxide-freezing temperature for the second intermediary fluid stream; expanding the second intermediary fluid stream to generate a third intermediary fluid stream, wherein the third intermediary fluid stream comprises solid carbon dioxide; separating the third intermediary fluid stream into a fourth intermediary fluid stream and an output fluid stream, wherein the output fluid stream comprises a liquefied natural gas (LNG) liquid; and utilizing the fourth intermediary fluid stream as a cooling fluid stream for the first heat exchanger.

Disclosed is a refrigeration and/or liquefaction method using a system that includes a low-temperature refrigeration device comprising a working circuit which forms a loop and contains a working fluid, the working circuit forming a cycle comprising, connected in series: a compression mechanism, a cooling mechanism, an expansion mechanism and a heating mechanism the refrigeration device further comprising a cooling exchanger for extracting heat from the useful fluid stream by exchanging heat with the working fluid flowing in the working circuit, the system comprising a pipe through which the useful fluid stream flows in the cooling exchanger, the method comprising a cooling step in which the refrigeration device is in a first operating mode for cooling the cooling exchanger while a useful fluid stream flows in the cooling exchanger, the method comprising, after said cooling step, a step of cleaning impurities that have solidified in the cooling exchanger, characterized in that during the cleaning step, the refrigeration device is in a second operating mode in which the working gas flows in the working circuit but in which the cooling exchanger cools less intensely than in the first operating mode.

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.

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 for removing a foulant from a gas stream is disclosed. The gas stream, containing a foulant, is cooled across a first heat exchanger and a second heat exchanger, producing a solid foulant entrained in cryogenic liquid as a foulant slurry, and a foulant-depleted gas stream. The foulant-depleted gas stream is passed through a cryogenic turbine and a first separation vessel, producing a light gas stream and further solid foulant. The solid foulants are recovered by a combination of pressurization, melting, and distillation to produce a liquid foulant product. Heat is recovered from the various streams in the various heat exchangers and the melter.

Methods and systems for cryogenically separating contaminants and regasification of LNG utilizing common refrigeration equipment and/or fuel. An integrated system includes: a component for separating contaminants from an input feed stream; a heat exchanger coupled to a first line, wherein: the first line is coupled to the component for separating contaminants, and the heat exchanger cools a first feed stream of the first line; and a LNG regasification system comprising a vaporizer, wherein: the vaporizer heats a LNG stream of the LNG regasification system, and the heat exchanger functions as the vaporizer. A process includes: separating contaminants from an input feed stream with a component for separating contaminants; cooling a first feed stream with a heat exchanger, wherein the heat exchanger is coupled to the component for separating contaminants; and heating a LNG stream with a vaporizer of a LNG regasification system, wherein the heat exchanger functions as the vaporizer.

A method and apparatus for liquefying a feed gas stream comprising natural gas and carbon dioxide. A method includes compressing an input fluid stream to generate a first intermediary fluid stream; cooling the first intermediary fluid stream with a first heat exchanger to generate a second intermediary fluid stream, wherein a temperature of the second intermediary fluid stream is higher than a carbon dioxide-freezing temperature for the second intermediary fluid stream; expanding the second intermediary fluid stream to generate a third intermediary fluid stream, wherein the third intermediary fluid stream comprises solid carbon dioxide; separating the third intermediary fluid stream into a fourth intermediary fluid stream and an output fluid stream, wherein the output fluid stream comprises a liquefied natural gas (LNG) liquid; and utilizing the fourth intermediary fluid stream as a cooling fluid stream for the first heat exchanger.

Methods and systems for removing contaminants, such as water and/or carbon dioxide, from a gas stream, such as a natural gas stream or a flue gas stream. One or more solid-tolerant heat exchangers are employed to chill the gas stream to a temperature at which the contaminants solidify. The solidified contaminants may then be separated and removed from the gas stream. In one or more aspects, the one or more solid-tolerant heat exchangers may include a scraped heat exchanger.

Methods and systems for removing contaminants, such as water and/or carbon dioxide, from a gas stream, such as a natural gas stream or a flue gas stream. One or more solid-tolerant heat exchangers are employed to chill the gas stream to a temperature at which the contaminants solidify. The solidified contaminants may then be separated and removed from the gas stream. In one or more aspects, the one or more solid-tolerant heat exchangers may include a scraped heat exchanger.

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.