A method and plant for the cryogenic separation of air, the plant having an air compressor, a heat exchanger and a distillation column system having a low-pressure column at a first pressure and a high-pressure column at a second pressure. Feed air is compressed in the air compressor to a third pressure at least 2 bar above the second pressure A first fraction of compressed feed air is cooled in the heat exchanger and expanded in a first expansion turbine. A second fraction is cooled in the heat exchanger and expanded in a second expansion turbine A third fraction is compressed to a fourth pressure, cooled in the heat exchanger and then expanded. The third fraction is compressed to the fourth pressure in sequence in a recompressor, a hot first turbine booster and a second turbine booster. A dense fluid expander is used to expand the third fraction.

Process and apparatus for producing pressurized gaseous nitrogen by cryogenic separation of air. The distillation column system includes a high pressure column, a medium pressure column, a main condenser and top condenser both being condenser-evaporators. Compressed and purified feed air is cooled in a heat exchanger and introduced to the distillation system. A gaseous nitrogen stream from the high pressure column is condensed in the main condenser. Bottom liquid of the medium pressure column is evaporated and gaseous nitrogen from the medium pressure column is condensed in the top condenser. Liquid nitrogen from the medium pressure column is pressurized and introduced to the high pressure column. A second gaseous nitrogen stream from the high pressure column is recovered as pressurized gaseous nitrogen product. A portion of the compressed and purified feed air is work-expanded and then warmed in the main heat exchanger.

An apparatus for the production of air gases with variable liquid production by the cryogenic separation of air can include a cold box having a heat exchanger, and a system of columns; a pressure monitoring device; and a controller. The cold box can be configured to receive a purified and compressed air stream under conditions effective for cryogenically separating the air stream to form an air gas product. The apparatus may also include means for transferring the air gas product from the cold box to an air gas pipeline. The pressure monitoring device is configured to monitor the pipeline pressure, and the controller is configured to adjust the product pressure of the air gas product coming out of the cold box based upon the pipeline pressure and to further adjust liquid production from the cold box based on the adjusted product pressure.

A method for obtaining an air product from an air separation plant having a distillation column system and a tank system. The tank system includes a first tank and a second tank. Cryogenic liquid is withdrawn from the distillation column system, stored in the tank system, and used as the air product. The cryogenic liquid is supplied to the first tank and withdrawn from the second tank during a first period, and is supplied to the second tank and withdrawn from the first tank during a second period. The tank system has a third tank to which cryogenic liquid withdrawn from the first tank and the second tank is transferred unheated. The air product is withdrawn from the third tank in liquid state, vaporized and discharged. Alternatively, the cryogenic liquid can be withdrawn from the third tank and stored in the liquid state in a fourth tank.

This invention is about an air separation apparatus to produce oxygen and nitrogen through isobaric separation, which is based on the Rankine cycle system of similar thermal energy power circulation apparatus at cryogenic side, a liquid pump is used to input work and the cold is made up to the air separation apparatus with refrigerating media, so as to realize the isobaric separation of air to produce nitrogen and oxygen. The air separation apparatus of this invention can save energy by over 30% as compared with the traditional advanced apparatus with the identical refrigerating capacity, and it can also realize centralize gas supply via the air separation apparatus, therefore it constitutes a breakthrough to the traditional air separation technology and refrigeration theory, with substantial economic, social and environmental protection benefits.

A cryogenic air separation method and apparatus in which first and second liquid streams are produced. The first liquid stream has a higher oxygen content than air and can consist of a higher pressure distillation column bottoms and the second liquid stream, for instance, air, has a lower oxygen content than the first liquid stream and an argon content no less than the air. The second liquid stream is subcooled through indirect heat exchange with the first liquid stream and both of such streams are introduced into the lower pressure column. The second liquid stream is introduced into the lower pressure column above that point at which the crude liquid oxygen column bottoms or any portion thereof is introduced into the lower pressure column to increase a liquid to vapor ratio below the introduction of the second liquid stream and therefore, reduce the oxygen present within the column overhead.

The invention relates to a high-atmospheric-pressure method for producing a pressurized oxygen-rich, gaseous air product. A first partial quantity of the feed air quantity is supplied at a temperature in a first temperature range to a first turbine unit (5), decompressed using same, and fed into a high-pressure column (111). A second partial quantity of the feed air quantity is supplied at a temperature in a second temperature range to a second turbine unit (6), decompressed using same, and fed into a low-pressure column (12). The pressurized, oxygen-rich air product is provided as an internal compression product at 16 to 50 bar, wherein evaporation is effected proceeding from a temperature in a third temperature range. The third temperature range lies above the first and second temperature range, the second temperature range is selected such that a two-phase mixture with a liquid proportion of 5 to 15% forms at the outlet of the second turbine unit (6), the temperature in the first temperature range and the temperature in the second differ from each other by not more than 10 K, and a portion of less than 5% of all air products removed from the air separation plant (100) is removed from the air separation plant in an unevaporated and liquid state. The first turbine unit is braked by a cold compressor (4), the second by a generator (G) or a warm booster. The invention also relates to an air separation plant (100).

A method of purifying air via a pre-purification unit (PPU) of an air separation unit (ASU) system having a pre-PPU chiller that is upstream of the PPU to cool compressed air before the compressed air is fed to the PPU can include passing air through an adsorber of the PPU to pass the air through a bed of adsorbent material within a vessel of the adsorber. In response to the pre-PPU chiller being determined to have an issue resulting in the pre-PPU chiller being tripped or requiring the pre-PPU chiller to be taken off-line, continuing to operate the ASU system at a full capacity even though nitrous oxide (N2O) within the air output from the PPU exceeds a first pre-selected threshold and is below a second pre-selected threshold associated with carbon dioxide (CO2) breakthrough. An ASU and a PPU can be designed to implement an embodiment of the method.

A system for extracting oxygen from a liquid includes a separator allowing a liquid to pass lengthwise through the separator to produce a liquid mixture with the liquid having at least a portion of oxygen removed from the liquid. The separator includes a wall surrounding an interior portion of a tube. The wall has at least one aperture formed in the wall. The separator also includes at least one magnet positioned adjacently to the at least one aperture. The magnet has a north pole end and a south pole end. A magnetic field gradient is formed between the north pole end and the south pole end, and extends into an interior portion of the tube. The system also includes a storage tank fluidly coupled to the at least one aperture for storing the at least a portion of the oxygen removed from the liquid via the separator.

Process and apparatus for producing pressurized gaseous nitrogen by cryogenic separation of air. The distillation column system includes a high pressure column, a medium pressure column, a main condenser and top condenser both being condenser-evaporators. Compressed and purified feed air is cooled in a heat exchanger and introduced to the distillation system. A gaseous nitrogen stream from the high pressure column is condensed in the main condenser. Bottom liquid of the medium pressure column is evaporated and gaseous nitrogen from the medium pressure column is condensed in the top condenser. Liquid nitrogen from the medium pressure column is pressurized and introduced to the high pressure column. A second gaseous nitrogen stream from the high pressure column is recovered as pressurized gaseous nitrogen product. A portion of the compressed and purified feed air is work-expanded and then warmed in the main heat exchanger.