A refrigerant circuit includes a first compression stage for compressing a mixed refrigerant gas, the first compression stage including at least a first compressor body and a second parallel compressor body, each compressor body including a suction inlet and an outlet, a first distribution means for splitting the flow of refrigerant gas to the first stage of compression across the at least two parallel compressor bodies, such that a first stream of refrigerant gas is fed to the suction inlet of the first compressor body and a second stream of refrigerant gas is fed to the suction inlet of the second compressor body, a second compression stage for compressing the mixed refrigerant gas, and a first merging means for recombining the first stream of refrigerant gas with the second stream of refrigerant gas downstream of the first compression stage for delivery to the second compression stage.

A process for producing liquefied natural gas, in which natural gas feed having methane and higher hydrocarbons including benzene is cooled down to a first temperature level in a first cooling step using a first mixed coolant and then subjected to a countercurrent absorption using an absorption liquid to form a methane-enriched and benzene-depleted gas fraction, wherein a portion of the gas fraction is cooled down to a second temperature level in a second cooling step using a second mixed coolant and liquefied to give the liquefied natural gas. In the plant proposed, the first and second mixed coolants are low in propane or free of propane, and the absorption liquid is formed from a further portion of the gas fraction which is condensed above the countercurrent absorption and returned to the countercurrent absorption without pumping. The present invention likewise provides a corresponding plant.

A heat exchanger having multiple plates which are mutually parallel and parallel to a longitudinal direction, the exchanger having a length measured in the longitudinal direction, the plates being stacked with spacing so as to define a first series of passages for the flow, in a general flow direction parallel to the longitudinal direction, of at least a first refrigerant fluid and a second refrigerant fluid, at least one passage of the first series being defined between two adjacent plates.

Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.

The present disclosure provides a heat axchanger and heat exchange method for cooling a gaseous process stream. The heat exchanger unit (100, 200, 300) comprises: a heat exchanger vessel (2), the heat exchanger vessel (2) comprising a plurality of process stream conduits (12, 14) arranged to receive the gaseous process stream (10) and discharge a cooled process stream (18), and a plurality of refrigerant conduits (46, 48, 49) to receive at least part of a pre-cooled mixed refrigerant stream (58) and to discharge at least one cooled mixed refrigerant stream (72, 82); at least one expansion device (74, 84) arranged to receive at least part of the cooled mixed refrigerant stream (72, 82) and discharge a further cooled mixed refrigerant stream (76, 86), the further cooled mixed refrigerant stream (76, 86) being connected to at least one of a third refrigerant inlet (77) and a fourth refrigerant inlet (87) of the heat exchanger vessel (2) to provide cooling to the process stream conduits (12, 14) and the refrigerant conduits (46, 48, 49); a refrigerant bleed vessel (110) arranged to receive a first refrigerant split-off stream (112) from the cooled mixed refrigerant stream (72, 82) and to receive a second refrigerant split-off stream (114) from the pre-cooled mixed refrigerant stream; the refrigerant bleed vessel (110) comprising a bleed outlet (116) to discharge a bleed stream (118) and a recycle outlet (120) to discharge a recycle stream (122), the recycle outlet being fluidly connected to at least one of the third refrigerant inlet (77) and the fourth refrigerant inlet (87) of the heat exchanger vessel (2).

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.

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 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 natural gas liquefaction system and method for effectively and efficiently removing heavy hydrocarbons and converting natural gas into liquefied natural gas. Natural gas streams entering the system may consist of varied gas compositions, pressures, and temperatures. In embodiments the system may comprise a natural gas (NG)-to-liquefied natural gas (LNG) portion and a closed-loop refrigeration portion comprising a closed-loop single mixed refrigerant system. In other embodiments the system may comprise an NG-to-LNG portion and a closed-loop refrigeration portion comprising a closed-loop gaseous nitrogen expansion refrigeration system. All embodiments utilize an integrated heat exchanger with cold-end and warm-end sections and integrated multi-stage compressor and expander configurations (e.g. compander) in order to increase overall operation flexibility and efficiency. This optimized method and system is capable of more efficiently producing a liquefied natural gas product at a desired capacity using a minimum amount of equipment and a modularized design to reduce construction costs.

A natural gas liquefaction system and method for effectively and efficiently removing heavy hydrocarbons and converting natural gas into liquefied natural gas. Natural gas streams entering the system may consist of varied gas compositions, pressures, and temperatures. In embodiments the system may comprise a natural gas (NG)-to-liquefied natural gas (LNG) portion and a closed-loop refrigeration portion comprising a closed-loop single mixed refrigerant system. In other embodiments the system may comprise an NG-to-LNG portion and a closed-loop refrigeration portion comprising a closed-loop gaseous nitrogen expansion refrigeration system. All embodiments utilize an integrated heat exchanger with cold-end and warm-end sections and integrated multi-stage compressor and expander configurations (e.g. compander) in order to increase overall operation flexibility and efficiency. This optimized method and system is capable of more efficiently producing a liquefied natural gas product at a desired capacity using a minimum amount of equipment and a modularized design to reduce construction costs.