Abstract: LNG is pumped to supercritical pressure and vaporized, preferably in an offshore location to thereby form a natural gas stream with an intermediate temperature. A first portion of that stream is then processed in an onshore location to remove at least some non-methane components to thereby form a lean LNG, which is then combined with a second portion of that stream to form a sales gas having desired chemical composition. The intermediate temperature and the split ratio of the gas stream in first and second portion are a function of the concentration of the non-methane components in the LNG.

Abstract: A method of controlling one or more refrigerant compressors (12) for one or more gaseous streams (10) at a normal operating temperature. At least one refrigerant compressor (12) has a vapour recirculation line (30). A compressor feed stream (10a) is provided from a combination of a vapour recirculation stream (30) from the vapour recirculation line (30) and an at least partly evaporated refrigerant stream (8). The compressor feed stream (10a) is passed through a suction drum (11) to provide a compressor gaseous stream (10), which is passed through the refrigerant compressor (s) (12). The inlet temperature T1 of the compressor gaseous stream (10) is determined, and cooling of a refrigerant stream is controlled in response to temperature T1 to provide the compressor gaseous stream (10) at the normal operating temperature of at least one refrigerant compressor (12).

Abstract: A refrigerant compressor circuit for use in a liquefaction plant includes a first compression string driven by a first driver; a second compression string driven by a second driver, a pre-cooling refrigerant compression stage arranged in the first compression string to receive a stream of pre-cooling refrigerant at an inlet pressure and discharge the pre-cooling refrigerant at an outlet pressure, a first compression stage arranged in the first compression string to compress a mixed refrigerant gas from a first pressure to a second pressure, and, a second compression stage arranged in the second compression string to compress the mixed refrigerant gas from the second pressure to a third pressure. The pre-cooling refrigerant compression stage and the first compression stage of the circuit are co-axially mounted on a first shaft drivingly coupled to a first driver in the first compression string.

Abstract: A floating system for liquefying natural gas comprising a vessel provided with a plant for liquefying natural gas having an inlet for natural gas and an outlet for liquefied natural gas, a feed supply system for supplying natural gas to the inlet of the plant, one or more storage tanks for storing liquefied natural gas, and an off-loading system for transporting liquefied natural gas between the storage tank(s) and a tanker, which floating system further comprises a vaporization system having an inlet for liquefied gas and an outlet for vapor.

Abstract: A system and method for cooling and liquefying a gas in a heat exchanger that includes compressing and cooling a mixed refrigerant using first and last compression and cooling cycles so that high pressure liquid and vapor streams are formed. The high pressure liquid and vapor streams are cooled in the heat exchanger and then expanded so that a primary refrigeration stream is provided in the heat exchanger. The mixed refrigerant is cooled and equilibrated between the first and last compression and cooling cycles so that a pre-cool liquid stream is formed and subcooled in the heat exchanger. The stream is then expanded and passed through the heat exchanger as a pre-cool refrigeration stream. A stream of gas is passed through the heat exchanger in countercurrent heat exchange with the primary refrigeration stream and the pre-cool refrigeration stream so that the gas is cooled.

Abstract: This process includes the cooling of an introduction stream (72) inside an upstream heat exchanger (28). It includes the introduction of the cooled introduction stream (76) into a fractionating column (50) and the tapping at the bottom portion of the column (50) of the denitrided stream of hydrocarbons. It also includes the introduction of a stream (106) rich in nitrogen obtained from the head portion of the column (50) into a separation container (60) and the recovery of the head gaseous stream from the separation container (60) in order to form the stream (20) which is rich in helium. The liquid stream (110) is obtained from the bottom of the first separation container (60) is separated into a liquid nitrogen stream (18) and a first reflux stream (114) which is introduced as reflux into the head of the fractionating column (50).

Abstract: A method and system for the small-scale production of LNG.

Abstract: A temperature-controlled vehicle including a cascade refrigeration system having a booster cooling line configured to supplement the cooling capacity of the cascade refrigeration system by expanding and venting a portion of a cryogenic refrigerant to the atmosphere during peak demands while the cascade refrigeration system continues to operate.

Abstract: A system for producing liquefied and sub-cooled natural gas by means of a refrigeration assembly using a single phase gaseous refrigerant comprises at least two expanders; a compressor assembly; a heat exchanger assembly for heat absorption from natural gas; and a heat rejection assembly, in which the expanders are arranged in expander loops and the refrigerant to the respective expander is served in a compressed flow by means of the compressor assembly having compressors or compressor stages enabling adapted inlet and outlet pressures for the respective expander.

Abstract: A method and system for producing liquefied and sub-cooled natural gas by means of a refrigeration assembly using a single phase gaseous refrigerant comprising: at least two expanders (1-3); a compressor assembly (5-7); a heat exchanger assembly (8) for heat absorption from natural gas; and a heat rejection assembly (10-12). The novel features according to the present invention are arranging the expanders (1-3) in expander loops; using only one and the same refrigerant in all loops; passing an expanded refrigerant flow from the respective expander into the heat exchanger assembly (8), each being at a mass flow and temperature level adapted to de-superheating, condensation or cooling of dense phase and/or sub-cooling of natural gas; and serving the refrigerant to the respective expander in a compressed flow by means of the compressor assembly having compressors or compressor stages enabling adapted inlet and outlet pressures for the respective expander.

Abstract: Method and apparatus for treating a mixed hydrocarbon feed stream (10), such as a natural gas stream. The mixed hydrocarbon feed stream (10) is expanded into a mixed-phase hydrocarbon stream (20), which is separated the to provide at least a light overhead stream (30) and a heavy bottom stream (50). The light overhead stream (30) is compressed in one or more first compressors (16) to provide one or more first compressed light streams (40) and further compressed in one or more second compressors (22) to provide one or more further compressed light streams (60). One or more first compressor recycle lines (42) extend around the or each first compressor (16), and one or more second compressor recycle lines (32) having one or more in-line coolers (34) extend around the or each second compressor (22). The method and apparatus may be used in a method of cooling an initial hydrocarbon stream (100).

Abstract: A method of natural gas liquefaction comprising first and second nitrogen refrigerant streams, each stream under-going a cycle of compression, cooling, expansion and heating, during which the first nitrogen stream is expanded to a first, intermediate pressure and the second nitrogen stream is expanded to a second, lower pressure, and the heating occurs in one or more heat exchangers in which at least one of the expanded nitrogen streams is in heat exchanging relationship with natural gas, wherein, in at least one of said one or more heat exchangers, the first and second expanded nitrogen streams are in a heat exchanging relationship with the natural gas and both the first and second compressed nitrogen streams.

Abstract: A method and apparatus are described to provide complete gas utilization in the liquefaction operation from a source of gas without return of natural gas to the source thereof from the process and apparatus. The mass flow rate of gas input into the system and apparatus may be substantially equal to the mass flow rate of liquefied product output from the system, such as for storage or use.

Abstract: A method of natural gas liquefaction may include cooling a gaseous NG process stream to form a liquid NG process stream. The method may further include directing the first tail gas stream out of a plant at a first pressure and directing a second tail gas stream out of the plant at a second pressure. An additional method of natural gas liquefaction may include separating CO2 from a liquid NG process stream and processing the CO2 to provide a CO2 product stream. Another method of natural gas liquefaction may include combining a marginal gaseous NG process stream with a secondary substantially pure NG stream to provide an improved gaseous NG process stream. Additionally, a NG liquefaction plant may include a first tail gas outlet, and at least a second tail gas outlet, the at least a second tail gas outlet separate from the first tail gas outlet.

Abstract: A method and apparatus for cooling and liquefying a hydrocarbon stream using a liquefaction process wherein a hydrocarbon stream is cooled and at least partially liquefied to obtain a liquefied hydrocarbon stream. In the method, one or more compressors are driven with one or more electric drivers, that are powered with one or more dual-fuel diesel-electric generators. These dual-fuel diesel-electric generations are operated by passing one or more hydrocarbon fuel streams to the one or more dual-fuel diesel-electric generators, wherein at least one of the one or more hydrocarbon fuel streams comprises a stream that is generated in the liquefaction process. The apparatus may be provided on a floating structure, a caisson, or off-shore platform.

Abstract: Method and apparatus for liquefying a hydrocarbon stream. A liquefaction system comprises at least an NGL recovery system 12, a main refrigerant circuit 42 and a first refrigerant circuit 100, a pressure reduction device 52 followed by an end gas/liquid separator 62. The main refrigerant circuit 42 comprises at least one or more main refrigerant compressors 45, 45a, 45b, and the first refrigerant circuit comprises one or more first refrigerant compressors 101. A hydrocarbon feed stream 10 is passed through the NGL recovery system 12 to produce a methane-enriched overhead stream 20, which is subsequently cooled and liquefied by the first and second refrigerant circuits. The pressure of the liquefied stream is reduced and the resulting mixed-phase stream 60 is passed through the end gas/liquid separator 62 to provide an end gaseous stream 70 and a liquefied hydrocarbon product stream 80.

Abstract: Process for efficiently operating a natural gas liquefaction system with integrated heavies removal/natural gas liquids recovery to produce liquefied natural gas (LNG) and/or natural gas liquids (NGL) products.

Abstract: A method of cooling at least two hydrocarbon streams such as natural gas, the method at least comprising the steps of: (a) providing at least first and second hydrocarbon streams (20, 20a); (b) passing the first hydrocarbon stream (20) through one or more first heat exchangers (12, 14) to provide a first cooled hydrocarbon stream (30); and (c) passing the second hydrocarbon stream (20a) through one or more second heat exchangers (12a, 14a) to provide a second cooled hydrocarbon stream (30a); wherein a refrigerant circuit (100) provides cooling to the first heat exchanger (s) (12, 14) and the second heat exchanger (s) (12a, 14a).

Abstract: A cryogenic turbine expander system which consists essentially of a cryogenic liquid pressure vessel, and the vessel further accommodating a turbine expander, an internal bypass configuration, which are operable in parallel, a three-way valve to direct incoming high pressure liquefied gas flow to the turbine expander, or the internal bypass configuration, which further consists a Joule-Thomson valve, when the turbine expander is not operational.

Abstract: A system and method according to which a compressor having a first shaft is provided, and an aeroderivative gas turbine for driving the compressor is provided, the aeroderivative gas turbine including a gas generator and a power turbine coupled to the gas generator, the power turbine having a second shaft directly coupled to the first shaft of the compressor for directly driving the first shaft.

Abstract: A power supply equipment (71) for natural gas liquefaction plant that supplies power to a natural gas liquefaction plant for liquefying the natural gas having impurities separated by a natural gas purification equipment (70). The power supply equipment comprises an air compressor (74); a combustion unit (75) for burning fuel with compressed air from the compressor to thereby generate a combustion gas; a gas turbine equipment (72) having a turbine rotated by the combustion gas from the combustion unit; and a cold heat source supply system (85) for, during the rated load operation of the gas turbine equipment, supplying carbon dioxide separated from the natural gas by the natural gas purification equipment to the gas turbine equipment as a cooling medium for the gas turbine equipment.

Abstract: The invention provides a method of cooling a process stream, the method comprising at least the steps of: (a) heat exchanging a first coolant supply stream in a first cooling circuit against a process stream at a first process temperature to produce a first coolant return stream and a cooled process stream; (b) passing the first coolant return stream to a first coolant return tank to provide warmed first coolant; (c) withdrawing a portion of the warmed first coolant from the first coolant return tank as a warmed first coolant stream; (d) heat exchanging a cooled second coolant stream in a second cooling circuit against the warmed first coolant stream to produce a cooled first coolant stream, (e) passing the cooled first coolant stream to a first coolant supply tank to provide cooled first coolant; (f) withdrawing a portion of the cooled first coolant from the first coolant supply tank as the first coolant supply stream; wherein the rate of flow of the warmed first coolant stream in step (c) is controlled in r

Abstract: Method of driving two or more refrigerant compressors in a hydrocarbon cooling process. In such a hydrocarbon cooling process a hydrocarbon feed stream (10) may be passed against partly evaporating refrigerant streams. The at least partly evaporated refrigerant streams (35a, 37a) are compressed through refrigerant compressors (34, 36). One or more gas turbines (54) are driven to provide electrical power (56) and hot gas. The hot gas (57) is passed through one or more steam heat exchangers (58) to provide steam power, which is used to drive one or more steam turbines (82) to drive at least one of the refrigerant compressors (34). The electrical power is used to drive (76) at least another one of the refrigerant compressors (36).

Abstract: A method of cooling a hydrocarbon stream such as natural gas from a feed stream (10), the method at least comprising the steps of: (a) passing the feed stream (10) and a first refrigerant stream (20) through a cooling stage (100) including one or more heat exchangers (12a, 12b) to provide a cooled hydrocarbon stream (30); and (b) circulating the first refrigerant stream (20) around a first refrigerant circuit (110) which includes one or more compressors (14), one or more coolers (16, 18) after the compressor (s), and a refrigerant accumulator (22) after the cooler (s); wherein there are no further coolers between the refrigerant accumulator (22) and the heat exchanger or the first of more than one heat exchanger (12a, 12b).

Abstract: A method of controlling the turndown of a compressor (12) for a gaseous hydrocarbon stream (10) such as natural gas, comprising at least the steps of: (a) passing the gaseous hydrocarbon stream (10) through the compressor (12) to provide a compressed hydrocarbon stream (20); (b) passing at least a fraction (30) of the compressed hydrocarbon stream (20) through an expander (14) which is mechanically interconnected with the compressor (12), to provide an expanded hydrocarbon stream (40); and (c) re-circulating part or all of the expanded hydrocarbon stream (40) through the compressor (12).

Abstract: A method for cooling natural gas with a refrigerant, one non-limiting embodiment which includes: (A) compressing and cooling the refrigerant to a first pressure to form a compressed refrigerant; (B) splitting the compressed refrigerant into a first stream and a second stream both at the first pressure; (C) cooling the first stream to form a cooled first stream; (D) expanding the cooled first stream to a first expansion pressure to form an expanded first stream; (E) compressing the second stream to a second pressure higher than the first pressure, forming a higher pressure second stream; (F) cooling the higher pressure second stream to form a cooled second stream; (G) expanding the cooled second stream to a second expansion pressure to form an expanded second stream; and, (H) Cooling the natural gas with the expanded first stream and expanded second stream, forming a cooled natural gas stream.

Abstract: A process is disclosed for liquefying a hydrocarbon-rich gas stream such as natural gas by indirect heat exchange with refrigerants in a cascade of three closed loop refrigeration cycles, namely pre-cooling, liquefaction and subcooling. Each of the closed loop refrigeration cycles utilizes a different refrigerant composition. The pre-cooling cycle utilizes a first mixed refrigerant; the liquefaction cycle utilizes a pure refrigerant; and the subcooling cycle utilizes a second next refrigerant. The refrigerants closely match the enthalpy curve of the hydrocarbon-rich gas, thereby improving the energy efficiency of the liquefaction process.

Abstract: A method and system for optimizing the efficiency of an LNG liquification system of the gas expansion type, wherein an incoming feed gas is first separated in a fractionation column by counter current contact with a cold reflux fluid, and a gaseous stream introduced into the heat exchanger system at a reduced temperature such that an intermediate pinch point is created in the warm composite curve.

Abstract: An operating system of a liquefied natural gas ship for performing sub-cooled liquefaction of boil-off gas includes a boil-off gas compressor, a cryogenic heat exchanger connected to a refrigerator system, and a first check valve and a first pressure control valve, installed in a pipe between a liquefied natural gas phase separator and a gas combustion unit, and a second check valve and a second pressure control valve, installed in a parallel pipe connected to the pipe in parallel. The parallel pipe is connected to a pipe between the boil-off gas compressor and the cryogenic heat exchanger such that boil-off gas is supplied to an upper vapor region of the liquefied natural gas phase separator. Thus, pressure and level of the liquefied natural gas phase separator are stably controlled. Power consumption is effectively reduced, and economical efficiency is achieved by stable operating pressure and level of the liquefied natural gas phase separator.

Abstract: A process for the production of a subcooled liquefied natural gas stream from a natural gas feed stream. Passing a first natural gas feed stream through a first heat exchanger for precooling by heat exchange with a first stream of gaseous refrigerant produced in a first refrigeration cycle comprising a first dynamic expansion turbine. Passing the precooled feed stream through a second heat exchanger for liquefying by heat exchange with a second stream of gaseous refrigerant produced in a second refrigeration cycle comprising a second dynamic expansion turbine. Passing the liquefied natural gas stream through a third heat exchanger for subcooling the liquefied gas by heat exchange with a third refrigerant stream produced in a third refrigeration cycle comprising a third dynamic expansion turbine separate from the first turbine and the second turbine.

Abstract: A method for liquefaction using a closed loop refrigeration system, the method comprising the steps of (a) compressing a gaseous refrigerant stream in at least one compressor; (b) cooling the compressed gaseous refrigerant stream in a first heat exchanger; (c) expanding at least a first portion of the cooled, compressed gaseous refrigerant stream from the first heat exchanger in a first expander to provide a first expanded gaseous refrigerant stream; and (d) cooling and substantially liquefying a feed gas stream to form a substantially liquefied feed gas stream in a second heat exchanger through indirect heat exchange against at least a first portion of the first expanded gaseous refrigerant stream from the first expander, wherein the first expanded gaseous refrigerant stream exiting the first expander is substantially vapor.

Abstract: A natural gas liquid plant includes a separator (103) that receives a cooled low pressure feed gas (4), wherein the separator (103) is coupled to an absorber (108) and a demethanizer (110). Refrigeration duty of the absorber (108) and demethanizer (110) are provided at least in part by expansion of a liquid portion of the cooled low pressure feed gas (4) and an expansion of a liquid absorber bottom product (19), wherein ethane recovery is at least 85 mol % and propane recovery is at least 99 mol %. Contemplated configurations are especially advantageous as upgrades to existing plants with low pressure feed gas where high ethane recovery is desirable.

Abstract: The invention relates to a process for liquefying a gas stream rich in methane, said process comprising: (a) providing said gas stream; (b) withdrawing a portion of said gas stream for use as a refrigerant; (c) compressing said refrigerant; (d) cooling said compressed refrigerant with an ambient temperature cooling fluid; (e) subjecting the cooled, compressed refrigerant to supplemental cooling; (f) expanding the refrigerant of (e) to further cool said refrigerant, thereby producing an expanded, supplementally cooled refrigerant; (g) passing said expanded, supplementally cooled refrigerant to a heat exchange area; and, (h) passing said gas stream of (a) through said heat exchange area to cool at least part of said gas stream by indirect heat exchange with said expanded, supplementally cooled refrigerant, thereby forming a cooled gas stream. In further embodiments for improved efficiencies, additional supplemental cooling may be provided after one or more other compression steps.

Abstract: A process for liquefying a gaseous methane-rich feed (20) to obtain liquefied natural gas, wherein a gaseous methane-rich feed at elevated pressure is conducted through a heat exchanger (1), where it is cooled, liquefied and sub-cooled against evaporating refrigerant. The liquefied product (21) is discharged from the heat exchanger. The refrigerant cycles in a closed loop, wherein the evaporated refrigerant (22) is removed from the heat exchanger, and is compressed (30) to get high pressure refrigerant which is cooled (31,32) and divided into a liquid (heavy) portion (24) and a gaseous (light) portion (25), which are conducted to the heat exchanger for sub-cooling and liquefying the gaseous methane-rich feed. The sub-cooled refrigerant portions are introduced (35,37) into the shell of the heat exchanger at respective positions for being evaporated.

Abstract: A method and apparatus for liquefying a hydrocarbon stream (10) such as natural gas. The method comprises the steps of: (a) compressing the hydrocarbon stream (10) using one or more compressors (12) driven by one or more steam turbines (14) to provide a compressed hydrocarbon stream (20); (b) heat exchanging the compressed hydrocarbon stream (20) against one or more refrigerant streams (40) to fully condense the compressed hydrocarbon stream (20) and provide a liquefied hydrocarbon stream (30) and one or more warmed refrigerant streams (50); (c) compressing at least one of the warmed refrigerant stream(s) (50) of step (b) using one or more compressors (18) driven by one or more gas turbines (22); and (d) at least partly driving one or more of the steam turbines (14) of step (a) using steam provided by one or more of the gas turbines (22) of step (c).

Abstract: A compact and modular cryogenic method and apparatus for liquefying natural gas. The liquefaction process is highly efficient and requires no external refrigeration system, and the apparatus is small enough to be transportable from one remote site to another. A compressed natural gas feed stream is cooled and then expanded to form a bi-phase stream comprising a first refrigerated vapor component and a first liquid component. The first liquid component is then separated from the bi-phase stream and expanded to form a second bi-phase stream comprising a second refrigerated vapor component and a second liquid component. The second liquid component is then introduced into a means configured for storage and transport. The remaining feed stream can then be recycled, and at least a substantial portion of the original feed stream can be processed into liquefied natural gas (LNG).

Abstract: A method and apparatus for liquefying a hydrocarbon stream such as natural gas from a feed stream. A feed stream is provided and passed through at least two cooling stages. Each cooling stage involves one or more heat exchangers. One of the heat exchangers involves a first refrigerant circuit having a first refrigerant stream, and a second of the heat exchangers involves a second refrigerant circuit having a second refrigerant stream. The liquefied hydrocarbon stream is expanded and a flash vapour is separated to provide a liquefied hydrocarbon product stream and a gaseous stream. The gaseous stream, at least a part of the first refrigerant stream, and at least a part of the second refrigerant stream are passed through a heat exchanger, for the gaseous stream to provide cooling to the first and second refrigerant streams.

Abstract: A natural gas liquefaction system with a turbine expander is provided that can improve the efficiency of the whole refrigeration cycle by using the turbine expander, instead of the throttling process that uses the conventional Joule-Thomson throttling valve that is used as a final throttling means in a conventional natural gas liquefaction system, and a liquefaction method thereof. The natural gas liquefaction cycle provided with the turbine expander of the present invention comprises a compressor 100, at least one vapor-liquid separator 300 or 310, a plurality of heat exchangers 200, 210, 220, 230 and 240, at least one Joule-Thomson throttling valves (below to be called JT valve) 400 and 410, a turbine expander 500, and connecting lines composed of plurality of pipes P1, P2, P3, P4, P5, P6 and P7 to connect these components.

Abstract: Method of liquefying a hydrocarbon stream such as natural gas from a feed stream (10), the method at least comprising the steps of: (a) circulating a first refrigerant stream (70) in a first refrigerant circuit (110); (b) cooling the first refrigerant stream (70) in one or more heat exchangers (14) of a first cooling stage (100) to provide a cooled first refrigerant stream (20); (c) passing at least part of the cooled first refrigerant stream (20) through one or more expanders to provide one or more expanded cooled first refrigerant streams (30); (d) passing the or at least one of the expanded cooled first refrigerant streams (30) and the feed stream (10) through the first one or more heat exchangers (14) to provide a cooled hydrocarbon stream (40); (e) passing the cooled hydrocarbon stream (40) through a second cooling stage (200) against a second refrigerant stream (50) to provide a liquefied hydrocarbon stream (60); wherein at least one expander is an expansion turbine (12) whose work energy created in ste

Abstract: Boiled off liquefied natural gas flows from a storage tank and is compressed in vapour compression stages. The resulting compressed vapour is condensed in a condenser and the condensate returned to the tank. The condenser is cooled by a working fluid, for example nitrogen, flowing in a Brayton cycle. The Brayton cycle includes a heat exchanger which removes heat of compression from the compressed natural gas vapour upstream of its passage through the condenser. In addition a part of the working fluid is withdrawn from a region of the Brayton cycle intermediate the working fluid outlet from the condenser and the working fluid inlet to the heat exchanger and the withdrawn working fluid flows through another heat exchanger in which it removes heat of compression from the natural gas vapour intermediate the compression stages. The withdrawn working fluid is returned to the Brayton cycle.

Abstract: Apparatuses and methods are provided for producing liquefied gas, such as liquefied natural gas. In one embodiment, a liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream may sequentially pass through a compressor and an expander. The process stream may also pass through a compressor. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. A portion of the liquid gas may be used for additional cooling. Gas produced within the system may be recompressed for reintroduction into a receiving line.

Abstract: A method of treating a hydrocarbon stream such as natural gas from a feed stream (10) comprising at least the steps of: a) passing the feed stream (10) through a distillation column (12) to provide a gaseous stream (20) and a C2+ liquid stream (30); b) compressing at least part of the gaseous stream (20) through one or more feed compressors (14, 16) to provide a compressed stream (40); and c) commonly driving (28) at least one of the feed compressors with one or more separate refrigerant compressors for one or more separate refrigerant circuits, by mechanically interconnecting said compressors.

Abstract: The present invention relates to a method of liquefying a hydrocarbon stream such as a natural gas stream, the method at least comprising the steps of: supplying a partly condensed hydrocarbon feed stream (10) to a first gas/liquid separator (2); separating the feed stream (10) in the first gas/liquid separator (2) into a gaseous stream (20) and a liquid stream (30); expanding the gaseous stream (20) thereby obtaining an expanded stream (40) and feeding it (40) into a second gas/liquid separator (3); feeding the liquid stream (30) into the second gas/liquid separator (3); removing from the bottom of the second gas/liquid separator a liquid stream (60) and feeding it into a fractionation column (5); removing from the top of the second gas/liquid separator (3) a gaseous stream (50) and passing it to a compressor (6) thereby obtaining a compressed stream (70); cooling the compressed stream (70) thereby obtaining a cooled compressed stream (80); heat exchanging the cooled compressed stream (80) against a stream b

Abstract: An LNG facility employing an enhanced nitrogen removal system that concentrates the amount of nitrogen in the feed stream to a nitrogen removal unit (NRU) to thereby increase the separation efficiency of the NRU. In one embodiment, the nitrogen removal system comprises a multistage separation vessel operable to separate nitrogen from a cooled natural gas stream. At least a portion of the resulting nitrogen-containing stream exiting the multistage separation vessel can be used as a refrigerant, processed to a nitrogen removal unit, and/or utilized as fuel gas for the LNG facility.

Abstract: Method and apparatus for liquefying a hydrocarbon stream such as natural gas. In the method, a hydrocarbon feed stream is passed through an NGL recovery system to separate the hydrocarbon feed stream into at least a methane-enriched overhead stream and a C2+ enriched bottom stream. The methane-enriched overhead stream is then passed through at least a first compressor to provide a methane-compressed stream, which is liquefied the to provide a first liquefied stream. The pressure of the first liquefied stream is reduced to provide a mixed-phase stream, which is passed through an end gas/liquid separator to provide an end gaseous stream and a liquefied hydrocarbon product stream. The end gaseous stream is passed through one or more end-compressors to provide an end-compressed stream, of which at least a recycle fraction is fed into the methane-enriched overhead stream. The temperature of the first liquefied stream may be controlled to change the amount of the end gaseous stream.

Abstract: A natural gas liquefaction system employing a high pressure pre-cooling refrigeration cycle. The natural gas liquefaction system can be advantageously employed in cold weather regions and/or in regions that exhibit large variations in ambient temperature.

Abstract: A method of liquefying natural gas from a feed stream (10) comprising at least the steps of: passing the feed stream (10) against a mixed refrigerant being cycled through a heat exchanger (12), to provide an at least partly liquefied hydrocarbon stream (20) having a temperature below ?100° C.; outflowing the mixed refrigerant as a liquid and vapour outflow refrigerant stream (80) and passing it through a first separator (18) to provide a vapour refrigerant stream (90) and a liquid refrigerant stream (110); recycling without substantial heat exchange the liquid refrigerant stream (110) into the heat exchanger (12); compressing and cooling the vapour refrigerant stream (90) to provide a cooled compressed stream (100) having a temperature below 0° C. and recycling it into the heat exchanger (12).

Abstract: An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through an expander creating work output. A compressor may be driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is divided into first and second portions with the first portion being expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. The second portion of the cooled, compressed process stream is also expanded and used to cool the compressed process stream.

Abstract: An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through an expander creating work output. A compressor may be driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is expanded to liquefy the natural gas. A gas-liquid separator separates a vapor from the liquid natural gas. A portion of the liquid gas is used for additional cooling. Gas produced within the system may be recompressed for reintroduction into a receiving line or recirculation within the system for further processing.

Abstract: Embodiments of this invention relate to a process for liquefaction of natural gas and other methane-rich gas streams, and more particularly to a process for producing liquefied natural gas (LNG). In a first step of the process, a first fraction of the feed gas is withdrawn, compressed to a pressure greater than or equal to 1500 psia, cooled and expanded to a lower pressure to cool the withdrawn first fraction. The remaining fraction of the feed stream is cooled by indirect heat exchange with the expanded first fraction in a first heat exchange process. In a second step a separate stream comprising flash vapor is compressed, cooled and expanded to a lower pressure providing another cold stream. This cold stream is used to cool the remaining feed gas stream in a second indirect heat exchange process. The expanded stream exiting from the second heat exchange process is used for supplemental cooling in the first indirect heat exchange step.