The invention relates to a method for condensing a gas, wherein the gas is subjected to cooling in indirect heat exchange with a refrigerant and at least part of the refrigerant is subjected, after the heat exchange with the gas, to compression by means of a drive (GT1) that produces waste heat and to a partial or complete condensing process. After the partial or complete condensing process, a first portion of the refrigerant is subjected to the heat exchange with the gas and a second portion of the refrigerant is subjected, in succession, to pressurization, heating by means of the waste heat of the drive (GT1) and work-performing expansion and thereafter is fed back to the partial or complete condensing process. The invention further relates to a corresponding system.

Liquefier arrangements configured for co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) configured to operate in two distinct operating modes are provided.

The present invention relates to a refrigerant composition. According to the invention it is envisioned that the composition comprises comprising an inert gas selected from nitrogen, argon, neon and a mixture thereof, and a mixture of at least two C.sub.1-C.sub.5 hydrocarbons. The present invention further relates to the use of the refrigerant composition in a method for liquefying a gaseous substance, particularly hydrogen or helium.

A drive system for liquefied natural gas (LNG) refrigeration compressors in a LNG liquefaction plant. Each of three refrigeration compression strings include refrigeration compressors and a multi-shaft gas turbine capable of non-synchronous operation. The multi-shaft gas turbine is operationally connected to the refrigeration compressors and is configured to drive the one or more refrigeration compressors. The multi-shaft gas turbine uses its inherent speed turndown range to start the one or more refrigeration compressors from rest, bring the one or more refrigeration compressors up to an operating rotational speed, and adjust compressor operating points to maximize efficiency of the one or more refrigeration compressors, without assistance from electrical motors with drive-through capability and variable frequency drives.

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 simultaneously liquefying CO2 and cooling natural gas, including providing a compressed CO2 loop, comprising a pressurized cooling stream, wherein a first compressed cooling stream and a second compressed cooling stream are produced by a CO2 compressor. Providing at least a portion of the first compressed cooling stream to a CO2 liquefaction system, wherein the first compressed cooling stream provides at least a portion of the refrigeration required by the CO2 liquefaction system. Providing at least a portion of the second compressed cooling stream to the pre-cooling system of a natural gas liquefaction system, wherein the second compressed cooling stream provides at least a portion of the refrigeration required by the natural gas pre-cooling.

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.

Certain embodiments of the invention relate to a facility for refrigerating hydrogen to cryogenic temperatures, and in particular for liquefying hydrogen, comprising a circuit for hydrogen to be refrigerated comprising an upstream end to be connected to a hydrogen source, and a downstream end connected to a refrigerated hydrogen collection member, the refrigeration facility comprising a set of one or more heat exchangers in thermal exchange with the circuit of hydrogen to be refrigerated, the facility comprising a device for refrigerating by heat exchange with the set of one or more heat exchangers, the refrigerating device comprising a refrigerator with a refrigeration cycle of a cycle gas such as hydrogen, at least one portion of the hydrogen circuit, of the set of one or more exchangers and of the refrigerating device being housed in a vacuum-insulated cold box, the facility comprising in the cold box, at least one ejector the suction inlet of which is connected to the gas phase of a fluid capacity and the motor fluid intake inlet of which is connected to at least one among: the pressurized cycle gas of the refrigerator, the hydrogen of the hydrogen circuit refrigerated in the set of one or more heat exchangers.

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.

Embodiments relate generally to systems and methods for pre-cooling a natural gas stream to a liquefaction plant. A system may include a compressor configured to receive a first natural gas stream at a first pressure and produce a second natural gas stream at a second pressure; an exchanger, wherein the exchanger is configured to receive the second natural gas stream as the second pressure and cool the second natural gas stream to produce a cooled natural gas stream; and an expander, wherein the expander is configured to receive the cooled natural gas stream and expand the cooled natural gas stream to produce a chilled natural gas stream from the second pressure to a third pressure.

An LNG liquefaction plant system, wherein the refrigeration content of the external or internal refrigerant is used to liquefy and sub-cool a natural gas stream to produce liquefied natural gas (LNG) in a cold box or cryogenic exchanger. The refrigerant may be an external gas (N.sub.2) or an internal (CH.sub.4—BOG) refrigerant working fluid expanded and compressed in a twin compander arrangement and compressed by a refrigerant compressor, or an external single mixed refrigerant (SMR) working fluid compressed by a refrigerant compressor and expanded thru a JT valve.