The present application includes a plant for treating gas, particularly natural gas, supplied by a transmission network. The plant includes a gas inlet connected to the transmission network, a portion of the plant that decompresses, to a predefined outlet pressure, a first fraction of the gas from the inlet, and supplies the decompressed gas at a first outlet. The plant also includes another portion that liquifies a second fraction of the gas from the inlet and supplies the liquefied gas at a second outlet. The portion that carries out the decompressing includes a valve for throttling the first gas fraction, a heat exchanger establishing a thermal exchange relationship between the decompressing portion placed downstream the throttle valve and the portion that liquifies and supplies the gas, another heat exchanger establishing a thermal exchange relationship between the plant portions placed downstream the first heat exchanger and upstream the throttle valve. The portion that liquifies and supplies also includes a valve for throttling the second gas fraction that is downstream the first heat exchanger.

A method for liquefying a feed gas stream. A refrigerant stream is cooled and expanded to produce an expanded, cooled refrigerant stream. Part or all of the expanded, cooled refrigerant stream is mixed with a make-up refrigerant stream in a separator, thereby condensing heavy hydrocarbon components from the make-up refrigerant stream and forming a gaseous expanded, cooled refrigerant stream. The gaseous expanded, cooled refrigerant stream passes through a heat exchanger zone to form a warm refrigerant stream. The feed gas stream is passed through the heat exchanger zone to cool at least part of the feed gas stream by indirect heat exchange with the expanded, cooled refrigerant stream, thereby forming a liquefied gas stream. The warm refrigerant stream is compressed to produce the compressed refrigerant stream.

A process of liquefying a natural gas stream in a liquefied natural gas facility is provided. The process includes cooling the natural gas stream in a first refrigeration cycle to produce a cooled natural gas stream. The process also includes cooling the cooled natural gas stream in a first chiller of a second refrigeration cycle, the cooled natural gas stream exiting the first chiller at a first pressure. The process further includes cooling the cooled natural gas stream in a first core of a second chiller of the second refrigeration cycle. The process yet further includes cooling a refrigerant of a refrigerant recycle stream separate from the cooled natural gas stream in a second core of the second chiller of the second refrigeration cycle, wherein the refrigerant recycle stream enters the second chiller at a second pressure that is lower than the first pressure of the cooled natural gas stream.

Systems and methods for improving the efficiency of open-cycle cascade-based liquified natural gas systems by utilizing one or more ejectors to reduce and/or eliminate compression stages. The systems and methods may thus, be used to improve the efficiency of new and preexisting open-cycle cascade-based liquified natural gas systems to reduce in the flow rate through each compressor, which reduces the energy consumption of the overall process.

Compressed rich natural gas is divided into a cooling gas stream and a fuel gas stream. The cooling gas stream is depressurized. The cooling gas and the fuel gas are then heat exchanged to provide a first cooling step to the fuel gas. The cooled fuel gas continues into a second cooling step in a second heat exchanger, and then flows into a separator vessel where liquids are removed from the bottom of the separator and conditioned fuel gas exits the top of the separator. The conditioned fuel gas from the separator and produced from its influent is depressurized and heat exchanged to provide the second cooling fluid for the second heat exchanger.

Provided is a natural gas liquefaction apparatus including: a cryogenic heat exchanger through which natural gas passes through and is liquefied into liquefied natural gas (LNG) through heat exchange with a first refrigerant and a second refrigerant; a first refrigerant cycle through which the first refrigerant circulates, which has some paths passing through the cryogenic heat exchanger to perform heat exchange, and which has a path of the first refrigerant divided into a plurality of paths after performing heat exchange at the cryogenic heat exchanger and performs expansion and pre-compression of the first refrigerant; and a second refrigerant cycle through which the second refrigerant circulates and which has some paths passing though the cryogenic heat exchanger.

A method of producing LNG. According to the method, a natural gas stream is compressed using first and second compressors. A cooler cools the natural gas stream so that the second compressor produces a cooled, compressed natural gas stream, which is liquefied in a liquefaction process. The liquefaction process uses a refrigerant compressor configured to compress a stream of refrigerant used to chill, condense, or liquefy the cooled, compressed natural gas stream. Using a heat recovery steam generation (HRSG) system, heat is recovered from a power source of the refrigerant compressor. A stream of pressurized steam is generated from the recovered heat. At least one of the first and second compressors is powered using at least part of the stream of pressurized steam.

A system and method for cooling a liquid cryogenic fluid user with an inert and non-pressurized liquid cryogen in 120K to 200K temperature range is provided. This includes maintaining the first liquid cryogenic fluid within a first predetermined temperature range with the sub-cooler and/or the recirculation pump, maintaining the second liquid cryogenic fluid within a second predetermined temperature range with the heat exchanger, and recondensing the second liquid cryogenic fluid using the pressurized first liquid cryogenic fluid.

A system and method for producing liquefied natural gas (LNG) from a natural gas stream. Each of a plurality of LNG trains liquefies a portion of the natural gas stream to generate a warm LNG stream in a first operating mode, and a cold LNG stream in a second operating mode. A sub-cooling unit is configured to, in the first operating mode, sub-cool the warm LNG streams to thereby generate a combined cold LNG stream. The warm LNG streams have a higher temperature than a temperature of the cold LNG streams in the second operating mode and the combined cold LNG stream. The combined cold LNG stream has, in the first operating mode, a higher flow rate than the flow rate of the cold LNG streams in the second operating mode.

A process for liquefying hydrogen gas including the following is disclosed: cooling the hydrogen gas to an intermediate temperature by heat exchange with a refrigerant circulating in a refrigeration loop provided with a higher temperature expander and a lower temperature expander, wherein the outlet stream from the lower temperature expander contains some condensed refrigerant; a means is provided of separating the condensate from the circulating refrigerant; and further cooling of the hydrogen gas by heat exchange with evaporation and reheating of the said condensate.

The fluid in the refrigeration loop is typically methane (such as natural gas after removal of carbon dioxide, water vapor and other impurities), or nitrogen, or a mixture thereof.