A method and apparatus for separating air in which an oxygen-rich liquid stream is pumped and then heated within a heat exchanger to produce an oxygen product through indirect heat exchange with first and second boosted pressure air streams. The first boosted pressure air stream is cold compressed at an intermediate temperature of the heat exchanger, reintroduced into the heat exchanger at a warmer temperature and then fully cooled and liquefied. The second boosted pressure air stream, after having been partially cooled, is expanded to produce an exhaust stream that is in turn introduced into a lower pressure column producing the oxygen-rich liquid. The second boosted pressure air stream is partially cooled to a temperature no greater than the intermediate temperature at which the cold compression occurs so that both the first and second boosted pressure air streams are able to take part in the heating of the oxygen-rich stream.

Method and plant for generating a synthesis gas which consists mainly of carbon monoxide and hydrogen and has been freed of acid gases, proceeding from a hydrocarbonaceous fuel, and air and steam, wherein low-temperature fractionation separates air into an oxygen stream, a tail gas stream and a nitrogen stream, wherein the tail gas stream and the nitrogen stream are at ambient temperature and the nitrogen stream is at elevated pressure, wherein the hydrocarbonaceous fuel, having been mixed with the oxygen stream and steam at elevated temperature and elevated pressure, is converted to a synthesis gas by a method known to those skilled in the art, and wherein acid gas is subsequently separated therefrom by low-temperature absorption in an absorption column, wherein the nitrogen stream generated in the fractionation of air is passed through and simultaneously cooled in an expansion turbine and then used to cool either the absorbent or the coolant circulating in the coolant circuit of the compression refrigeration plant.

The invention relates to a method and device for obtaining compressed oxygen and compressed nitrogen by the low-temperature separation of air in a distillation column system for nitrogen-oxygen separation, said distillation column system having at least one high-pressure column (8) and one low-pressure column (460), wherein the low-pressure column (460) is in a heat-exchanging connection with the high-pressure column (8) by means of a main condenser (461) designed as a condenser-evaporator. Feed air is compressed in an air compressor (2). The compressed feed air (6, 734, 802, 840) is cooled down in a main heat exchanger (20) and at least partially introduced into the high-pressure column (8). An oxygen-enriched liquid (462, 465) is removed from the high-pressure column (8) and fed to the low-pressure column (460) at a first intermediate position (464, 467, 906). A nitrogen-enriched liquid (468, 470) is removed from the high-pressure column (8) and/or the main condenser (461) and fed to the head of the low-pressure column (460). A liquid oxygen flow (11, 12) is removed from the distillation column system for nitrogen-oxygen separation, brought to an elevated pressure in the liquid state (13), introduced into the main heat exchanger (20) at said elevated pressure, evaporated or pseudo-evaporated and heated to approximately ambient temperature in the main heat exchanger (20), and finally obtained as a gaseous compressed oxygen product (14). A high-pressure process flow (34, 734) is brought into indirect heat exchange with the oxygen flow in the main heat exchanger (20) and then depressurized (36, 38; 736, 738), wherein the depressurized high-pressure flow (37, 737) is introduced at least partially in the liquid state into the distillation column system for nitrogen-oxygen separation. A gaseous circuit nitrogen flow (18, 19) is drawn from the high-pressure column and at least partially (21) compressed in a circuit compressor (22). A first sub-flow (45, 46; 244, 242, 230; 845, 846) of the circuit nitrogen flow is removed from the circuit compressor (22, 322), cooled down in the main heat exchanger (20), at least partially condensed in the bottom evaporator (9, 209) of the high-pressure column (8) in indirect heat exchange with the bottom liquid of the high-pressure column (8), and conducted back into the distillation column system for nitrogen-oxygen separation. A second sub-flow of the circuit nitrogen flow is branched

A method for low-temperature air separation, in which an air-separation system having a column system is used that has a first column, a second column, a third column, and a fourth column, wherein fluid from the first column is fed at least into the second column, fluid from the second column is fed at least into the third column, fluid from the third column is fed at least into the fourth column, and fluid from the fourth column is fed at least into the third column, and wherein the fluid fed from the third column into the fourth column includes at least a portion of a side flow, which is withdrawn from the third column and has a lower oxygen content and a higher argon content than the third sump liquid. The present invention also relates to a corresponding system.

A method for obtaining one or more air products by means of an air separation unit comprising a first booster, a second booster, a first decompression machine, and a rectification column system which has a high-pressure column operated at a first pressure level and a low-pressure column operated at a second pressure level below the first pressure level. All of the air supplied to the rectification column system is first compressed to a third pressure level, which lies at least 3 bar above the first pressure level, as a feed air quantity. A first fraction of the feed air quantity is supplied to a first booster at the third pressure level and at a temperature level of −140 to −70 ° C. and is compressed to a fourth pressure level using the first booster.

The present invention relates to a method and system for producing liquefied natural gas (LNG) from a stream of pressurized natural gas which involves a combination of mechanical refrigeration.

A system and method for removing nitrogen and producing a high pressure methane product stream and an NGL product stream from natural gas feed streams where at least 90%, and preferably at least 95%, of the ethane in the feed stream is recovered in the NGL product stream. The system and method of the invention are particularly suitable for use with feed streams in excess of 5 MMSCFD and up to 300 MMSCFD and containing around 5% to 80% nitrogen. The system and method preferably combine use of strategic heat exchange between various process streams with a high pressure rectifier tower and the ability to divert all or a portion of a nitrogen rejection unit feed stream to optionally bypass a nitrogen fractionation column to reduce capital costs and operating expenses.

Described herein are systems and processes to produce liquefied natural gas (LNG) using liquefied nitrogen (LIN) as the refrigerant. Greenhouse gas contaminants are removed from the LIN using a greenhouse gas removal unit. The LNG is compressed prior to being cooled by the LIN.

Various embodiments include an apparatus for liquefying gas comprising: an inlet for a pressurized gas; a countercurrent heat exchanger with a first channel for the pressurized gas to flow in a first direction; an expansion nozzle, such that the pressurized gas flows from the first channel into the nozzle, and flows out to form an aerosol comprising a gaseous phase and liquid droplets; an aerosol breaker separating at least some of the droplets out of the gaseous phase; a collecting region for gathering and collecting droplets dripping off the aerosol breaker; and a second channel of the countercurrent heat exchanger surrounding the first channel. The flow of the gaseous phase out of the expansion nozzle is colder compared to the gas flowing through the second channel in a second direction opposite to the first direction. The second channel surrounds the first channel. The apparatus comprises a monolithic structure.

A method and apparatus for separating air in which an oxygen-rich liquid stream is pumped and then heated within a heat exchanger to produce an oxygen product through indirect heat exchange with first and second boosted pressure air streams. The first boosted pressure air stream is cold compressed at an intermediate temperature of the heat exchanger, reintroduced into the heat exchanger at a warmer temperature and then fully cooled and liquefied. The second boosted pressure air stream, after having been partially cooled, is expanded to produce an exhaust stream that is in turn introduced into a lower pressure column producing the oxygen-rich liquid. The second boosted pressure air stream is partially cooled to a temperature no greater than the intermediate temperature at which the cold compression occurs so that both the first and second boosted pressure air streams are able to take part in the heating of the oxygen-rich stream.