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 plant and process are used to liquefy and purify a high pressure ethane feed stream. The plant includes a cascaded refrigeration system that refrigerates the ethane feed stream. The refrigeration system includes a propylene circuit, an ethylene circuit and a mixed refrigerant circuit. The mixed refrigerant circuit includes a refrigerant that includes ethane and methane. The plant includes a demethanizer that is configured to remove methane and other natural gas liquids from the refrigerated ethane stream.

The present disclosure designs a mixed refrigerant hydrogen liquefaction device including a normal-pressure precooling cold box, a vacuum cryogenic cold box, a hydrogen refrigeration cycle compressor unit, a nitrogen cycle refrigeration unit and a mixed refrigerant cycle refrigeration unit. The precooling section uses a mixed refrigerant process and a nitrogen cycle refrigeration process as the main sources of cold energy. The refrigerant refrigeration cycle is the main source of cold energy in the temperature range of 303K to 113K. The liquid nitrogen refrigeration cycle is the main source of cold energy in the temperature range of 130K to 80K. The hydrogen refrigeration cycle provides cold energy for the temperature range of 80K to 20K. Most of the BOG generated in a storage part is recovered by an ejector. A plate-fin heat exchanger is filled with ortho-para hydrogen conversion catalysts to realize the para hydrogen content of liquefied hydrogen ≥98%.

A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.

A plant and process are used to liquefy and purify a high pressure ethane feed stream. The plant includes a cascaded refrigeration system that refrigerates the ethane feed stream. The refrigeration system includes a propylene circuit, an ethylene circuit and a mixed refrigerant circuit. The mixed refrigerant circuit includes a refrigerant that includes ethane and methane. The plant includes a demethanizer that is configured to remove methane and other natural gas liquids from the refrigerated ethane stream.

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.

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 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.

A natural gas liquefying apparatus is provided. At least a part of a cooling region, in which a precooling unit and a liquefaction unit are arranged, and at least a part of a compression region, in which first and second compressors compressing refrigerants to be used in the precooling unit and the liquefaction unit are arranged, are arranged to be opposed to each other across a long side of a second refrigerant cooler group arrangement region in which a liquefying refrigerant is cooled. A first refrigerant cooler group arrangement region, in which a precooling refrigerant is cooled, is arranged so that a long side of the first refrigerant cooler group arrangement region is opposed to one side of a rectangular region including the compression region, the one side being different from a side of the rectangular region opposed to a long side of the second refrigerant cooler group arrangement region.

A natural gas liquefying apparatus includes: a precooling unit, which is a treatment unit configured to precool natural gas; a liquefying unit, which is a treatment unit configured to liquefy the natural gas; a refrigerant cooling unit, which is a treatment unit configured to cool a liquefying refrigerant; a compression unit configured to compress vaporized refrigerants; and a pipe rack including air-cooled coolers arrayed and arranged on an upper surface. The treatment units and the compression unit are separately arranged in a first arrangement region and a second arrangement region arranged opposed to each other across a long side of the pipe rack. The pipe rack interposed between the first and second arrangement regions has a region in which no air-cooled cooler is arranged in order to arrange a plurality of pipes, through which refrigerants are allowed to flow, in a direction of a short side of the pipe rack.