Abstract: with a Variable Proportion of Liquid Product In a single column distillation system for obtaining gaseous and liquid nitrogen with a variable proportions of liquid product by low-temperature separation from air, a first portion (12, 13) of nitrogen-rich fraction (5, 7, 8) is fed downstream of circulation compressor (9) to the liquefaction chamber of a condenser-evaporator (14) associated with the single column and condensed under a pressure higher than the operating pressure of the single column (4). A liquid oxygen-enriched fraction (228, 231) from the distillation column system is at least partially evaporated in the evaporation chamber of condenser-evaporator (14). A portion (18) of nitrogen-rich liquid (15, 16) from condenser-evaporator (14) is drawn off at least at times as liquid product.

Abstract: For producing a pressurized product by low-temperature producing a pressurized product by low-temperature fractionation of air in a rectification system which has a high-pressure column (13) and a low-pressure column (14), a first feed airstream (12) is introduced into the high-pressure column (13), and an oxygen-rich fraction (38) from the low-pressure column (14) is brought (39) to pressure in the liquid state and introduced (41) into a mixing column (16). A second feed airstream (6, 15) is introduced into the lower region of the mixing column (16) and brought into countercurrent contact with the oxygen-rich fraction (41). The mixing column (16) is operated at a pressure (PM1S) which is lower than the operating pressure (pHDS) of the high-pressure column (13).

Abstract: For obtaining gaseous nitrogen by low-temperature separation from air, a distillation column system has a single column (4). Compressed air (1) is cooled in a main heat exchanger (2) and fed (3) to single column (4). A nitrogen-rich fraction (5, 7, 8) is drawn off from the distillation column system and compressed at least in part in a circulation compressor (9, 1063). A first part (12, 13) of nitrogen-rich fraction (5, 7, 8) is fed downstream from circulation compressor (9) to the liquefaction chamber of a condenser-evaporator (14) and is condensed under a pressure higher than the operating pressure of single column (4), so to form nitrogen-rich liquid (15, 16). A liquid oxygen-enriched fraction (231) from the distillation column system is at least partially evaporated in the evaporation chamber of condenser-evaporator (14). A first oxygen-enriched gas (234, 533) formed in the evaporation chamber of condenser-evaporator (14), is introduced into single column (4).

Abstract: The process and the apparatus serve to produce pressurized nitrogen by low-temperature fractionation of air in a rectification system which has a pressure column (4) and a low-pressure column (5). Feed air (1, 3) is passed into the pressure column (4). An oxygen-containing liquid fraction (11) is taken off from the pressure column (4) and fed into the low-pressure column (5). Gaseous nitrogen (18) from the low-pressure column (5) is at least partially condensed in a top condenser (17) by indirect heat exchange with an evaporating liquid (13). Nitrogen from the low-pressure column is produced as gaseous pressurized nitrogen product (24, 25, 29) at a pressure which is higher than the operating pressure of the low-pressure column (5). Liquid nitrogen (20) withdrawn from the low-pressure column is brought (21) in the liquid state to a pressure which exceeds the pressure of the low-pressure column (5).

Abstract: In the method and device, nitrogen is obtained by two-stage rectification of air in a double column. Double column contains a high-pressure column and a medium-pressure column that are in a heat-exchange relationship with each other. Entering air is compressed, purified, cooled in a main heat exchanger against separation products, and fed to rectification. At least one nitrogen product fraction is taken from high-pressure column. A nitrogen gas fraction from double column is heated, expanded, and brought into indirect heat exchange with an oxygen-enriched liquid from the lower region of medium-pressure column. In this way, the nitrogen gas fraction is at least partially condensed and the oxygen-enriched liquid is at least partially evaporated. The condensate formed in the indirect heat exchange is at least partially fed to medium-pressure column.

Abstract: The method and the apparatus are used to obtain oxygen and nitrogen at superatmospheric pressure by low-temperature separation of air in a rectification column system. Compressed and purified feed air (1, 3) is introduced into a pressure column (4). Liquids (5, 8) from the lower region and, respectively, from the upper or middle region of the pressure column (4) are fed into the low-pressure column (7). A third liquid fraction (17) from the lower region of the low-pressure column (7) is evaporated in indirect heat exchange (12) with condensing vapour (11) from the upper region of the pressure column (4), at least a portion of the vapour (22, 24, 26, 27) obtained in the process being introduced into the low-pressure column (7). Condensate (13) is fed into the pressure column (4); A pressurized nitrogen fraction (10, 14, 15) is extracted as product from the upper region of the pressure column (4).

Abstract: For air fractionation by two-stage rectification with subsequent production of crude argon, a component stream of the crude argon stream (25, 31) withdrawn from the crude argon column (2) is condensed (35) in indirect heat exchange (34) with a liquid oxygen product stream (40) from the medium pressure column (4), the oxygen product stream (40) being partially vaporized. The condensed crude argon (35) is then recycled into the crude argon column (20). A second component stream of the crude argon is obtained as the product (24).

Abstract: A process and an apparatus are disclosed for air fractionation by means of rectification. Nitrogen (16) withdrawn from the process is heated to an intermediate temperature, withdrawn, in part (30), out of the primary heat exchanger (17), and engine-expanded (31). The resultant expanded gas (32) transfers its cold in the primary heat exchanger (17) to air to be fractionated (1) and is then recompressed (33, 36).

Abstract: An air separation system is provided comprising a double rectification column associated with a raw argon column, the latter being operated at a pressure substantially lower than the low-pressure part of the double column. A coupled turbine-compressor system is used: (a) to lower the pressure of the argon-containing gas entering a raw argon column from the low-pressure column; and (b) to compress evaporated liquid stemming from the high-pressure column which has been used to indirectly condense raw argon product at the top of the raw argon column. Also, a pump is employed to remove liquid from the bottom of the raw argon column and recycle it to the low-pressure column.

Abstract: In a process and apparatus for air separation by rectification air 1 is preliminarily separated in a first rectification stage 2 of a two-stage rectification column to obtain a nitrogen-rich fraction 4 and an oxygen-rich fraction 8. These two fractions are fed to the second rectification stage 6 and separated into oxygen and nitrogen fractions. An argon-enriched fraction, containing essentially oxygen and argon, is removed from the second rectification stage at an intermediate point and is separated in a raw argon column 10 by rectification into an argon-rich fraction 18 and a liquid fraction 19 containing essentially oxygen. The liquid fraction 19 is fed back into the second rectification stage. Another fraction 22 is removed from the raw argon column above the bottom thereof and is separated in a high-purity oxygen column 23 to produce a high-purity oxygen fraction 25, 26 and a lighter residual fraction 24.