A method for the liquefaction of an industrial gas by integration of a methanol plant and an air separation unit (ASU) is provided. The method can include the steps of: (a) providing a pressurized natural gas stream, a pressurized purge gas stream originating from a methanol plant, and a pressurized air gas stream comprising an air gas originating from the ASU; (b) expanding three different pressurized gases to produce three cooled streams, wherein the three different pressurized gases are the pressurized natural gas stream, the pressurized purge gas stream, and the pressurized air gas stream; and (c) liquefying the industrial gas in a liquefaction unit against the three cooled streams to produce a liquefied industrial gas stream. The industrial gas to be liquefied is selected from the group consisting of a first portion of the pressurized natural gas stream, a nitrogen gas stream, hydrogen and combinations thereof.

A method for the liquefaction of an industrial gas by integration of a methanol plant and an air separation unit (ASU) is provided. The method can include the steps of: (a) providing a pressurized natural gas stream, a pressurized purge gas stream composed predominately of hydrogen and originating from a methanol plant, and a pressurized air gas stream comprising an air gas from the ASU; (b) expanding three different pressurized gases to produce three cooled streams, wherein the three different pressurized gases consist of the pressurized natural gas stream, the pressurized purge gas stream, and the pressurized air gas stream; and (c) liquefying the industrial gas in a liquefaction unit against the three cooled streams to produce a liquefied industrial gas stream, wherein the industrial gas to be liquefied is selected from the group consisting of a first portion of the pressurized natural gas stream, a nitrogen gas stream, hydrogen and combinations thereof

It is proposed to integrate a gas processing unit with a liquefaction unit. The industrial gas stream may be but is not limited to air gases of oxygen, nitrogen argon, hydrocarbon, LNG, syngas or its components, CO.sub.2, or any other molecule or combination of molecules. It is proposed to integrate the underutilized process inefficiencies of a gas processing unit into the liquefaction unit to produce a liquid at a reduced operating cost. The gas processing unit may be any system or apparatus which alters the composition of a feed gas. Examples could be, but are not limited to, a methanol plant, steam methane reformer, cogeneration plant, and partial oxidation unit.

Methods and systems providing a process for cooling and liquefying a purified gaseous hydrogen feed stream to a liquid hydrogen stream that may be stored in a liquid hydrogen storage tank, as well as a system wherein ortho-hydrogen (o-H2) contained in the purified gaseous hydrogen feed stream may be converted to para-hydrogen (p-H2) through serial low-temperature catalytic converters along the cooling process from normal ambient temperature (300K) to the liquefied temperature about (20K) of the hydrogen.

A method of natural gas liquefaction includes at least two nitrogen refrigerant streams. Each stream undergoes a cycle of compression, cooling, expansion and heating, during which each of the nitrogen streams is expanded to a different pressure other than for the others of the at least two nitrogen streams, and, the heating occurs in one or more heat exchangers. The expanded nitrogen streams are in a heat exchanging relationship with a stream of the natural gas and with the one or more compressed nitrogen streams in at least one of the one or more heat exchangers. At least one expanded nitrogen stream is compressed as a side stream in a stage of a main nitrogen compressor so as to combine the compressed side stream with another compressed nitrogen stream after passing the nitrogen compressor stage.

A system and method for providing supplemental refrigeration to an air separation plant is provided. A closed loop supplemental refrigeration circuit that can be easily retrofitted or added onto an air separation plant that increases the liquid product production capability of the air separation plant. The supplemental refrigeration capacity of the supplemental refrigeration circuit is controlled by removing or adding a portion of the refrigerant in the supplemental refrigeration circuit to adjust the inlet pressure while maintaining a substantially constant volumetric flow rate and substantially constant pressure ratio across the compressor. Removing the refrigerant from the supplemental refrigeration circuit decreases the refrigeration imparted by the supplemental refrigeration circuit and thus provides the capacity to turn-down liquid product make without shutting down the compressors and turbo-expanders in the supplemental refrigeration circuit.

A process and apparatus for liquefying a gas stream comprising hydrocarbons and sour species is provided in which the sour species are removed in liquefied form as the sweetened gas stream is progressively cooled to liquefaction temperatures. The process involves cooling the gas stream in a manner to produce a cooled gas stream comprising gaseous hydrocarbons and residual sour species. The cooled gas stream is then treated with a cold solvent to deplete the cooled gas stream of residual sour species. The resulting cooled sweetened gas stream is then further cooled to produce liquid hydrocarbons.

A method and apparatus for liquefying a gaseous hydrocarbon stream such as natural gas. The method comprises at least the steps of providing a feed stream (10) and dividing the feed stream (10) to provide at least a first stream (20) and a second stream (30). The first stream (20) is liquefied using heat exchange against a liquid nitrogen stream (40) to provide a first liquefied hydrocarbon stream (60) and an at least partly evaporated nitrogen stream (70). The second stream (20) is cooled and liquefied by heat exchanging against the at least partly evaporated nitrogen stream (70) to provide a second cooled hydrocarbon stream (80).

The present techniques are directed to a system and method for generating power and producing liquefied natural gas (LNG). The system includes a power plant configured to generate power, wherein an exhaust gas from the power plant provides a gas mixture including nitrogen and carbon dioxide. The system also includes a dehydration system configured to dehydrate the gas mixture to generate a nitrogen refrigerant stream and a refrigeration system configured to produce LNG from a natural gas stream using the nitrogen refrigerant stream.

A process for producing high-purity methane is disclosed wherein a mixture containing predominantly methane, and at least one higher hydrocarbon, such as ethane or propane, and nitrogen is liquefied and fed to a first fractionation column that removes nitrogen and other light gases from the mixture through the top of the first fractionation column as a vapor. The remainder of the mixture is fed to a second fractionation column that removes the higher hydrocarbons and other heavier components through the bottom of the second fractionation column as a liquid producing high-purity methane out the top of the second fractionation column as a vapor. The high-purity methane vapor is warmed, compressed, and liquefied by heat exchange. The liquid leaving the second fractionation column can be further purified in a stripping column to remove non-hydrocarbon components such as carbon dioxide.