Abstract: A first stream of compressed, cooled air is introduced into a higher pressure rectification column through an inlet and is separated into nitrogen vapour and oxygen-enriched liquid. At least some of the nitrogen vapor is condensed in a condenser and one stream of the resulting liquid nitrogen is used as reflux in the column and another stream as reflux in a lower pressure rectification column. Oxygen enriched liquid withdrawn from the column through an outlet is separated in the column. Impure liquid oxygen product is withdrawn from the column through an outlet. A less pure stream of liquid oxygen is withdrawn from the column through an outlet, is reboiled in a condenser-reboiler by indirect heat exchange with a second stream of air and is reintroduced into the column at its bottom through an inlet.

Abstract: A medium purity gaseous oxygen cycle in which reboil for the LP column is provided partly by nitrogen from the HP column and partly by a stream of air.

Abstract: Air is rectified in a rectification system comprising a higher pressure rectification column, an intermediate pressure rectification column, and a lower pressure rectification column. A first reboiler-condenser provides liquid nitrogen reflux for the higher pressure rectification column and for the lower pressure rectification column and also reboils the intermediate pressure rectification column. Another reboiler-condenser provides liquid nitrogen reflux for the intermediate pressure rectification column and reboils the lower pressure rectification column. Air is fed to the higher pressure rectification column through a pair of inlets. A first oxygen product is withdrawn from the intermediate pressure rectification column by a pump. Gaseous nitrogen products are withdrawn from the intermediate and lower pressure rectification columns through a pair of outlets thereof.

Abstract: In a process integration, particularly with a blast furnace, nitrogen under pressure is moisturized by the addition to it of hot, pressurized water. The moisturized nitrogen is expanded and power thereby generated. The nitrogen is not mixed with combustion gases. Improved heat balance and work recovery are achieved.

Abstract: An improvement to a gaseous oxygen cycle in which refrigeration is provided by two expansion turbines each fed with nitrogen. In addition, some nitrogen is recompressed, returned though the main heat exchanger, condensed and used to form a liquid nitrogen product.

Abstract: In a process integration, particularly with a blast furnace, low grade fuel gas produced by the furnace is compressed and moisturized. The moisturized fuel is burnt using a major part of a compressed air stream to support its combustion. The resulting combustion gases are then expanded with the generation of power. The minor part of the air is separated into oxygen and nitrogen. Oxygen is used in the blast furnace.

Abstract: A method of separating air in which a compressed air stream is divided into first and second subsidiary streams. The first subsidiary air stream is cooled by heat exchange to a temperature suitable for its separation by rectification and introduced into the higher pressure stage of a double rectification column. The second subsidiary air stream is further compressed and then at least part of it is cooled by heat exchange to a first intermediate temperature below ambient temperature but above those temperatures at which the double rectification column operates. The thus cooled second subsidiary air stream is expanded in a first expansion turbine and is withdrawn therefrom at a second intermediate temperature below the first intermediate temperature but above those temperatures at which the double rectification column operates. After withdrawal, the second subsidiary air stream is introduced into a second expansion turbine where it is further expanded.

Abstract: Air is taken from the air compressor of a gas turbine including in addition to the compressor a combustion chamber and an expansion turbine. The gas turbine drives an alternator. The air taken from the compressor is cooled in heat exchanger to remove heat of compression therefrom. The air is separated in an air separation plant into oxygen and nitrogen. A stream of oxygen is withdrawn from the plant and used in a blast furnace in which iron is made. The off-gas from the blast furnace is a low grade gaseous fuel. It is compressed in compressor which has interstage cooling to remove at least some of the heat of compression. The compressed fuel gas is passed through the heat exchanger countercurrently to the air stream. The resulting pre-heated fuel gas flows into the combustion chamber of the gas turbine and is burned therein to generate gaseous combustion products that are expanded in the turbine. A nitrogen stream is withdrawn in the air separation plant.

Abstract: Air is compressed in a compressor and has water vapor and carbon dioxide removed therefrom in an apparatus. A portion of the resulting purified air is then cooled by passage through a main heat exchanger to a temperature suitable for its separation by rectification. The air is then introduced into the higher pressure stage of a double rectification column (which also has a lower pressure stage). Liquid oxygen is withdrawn from the lower pressure stage by a pump and is vaporized by passage through the heat exchanger countercurrently to the aforementioned air to form a high pressure gaseous oxygen product. A second portion of the purified air is further compressed in compressors and is then passed through the heat exchanger 6 countercurrently to the oxygen product, thereby helping to warm such product. A part of the first portion of air is withdrawn from an intermediate region of the heat exchanger, is expanded in a turbine and is introduced into the lower pressure rectification stage.

Abstract: The present invention provises a method and apparatus for separating a gas mixture. In accordance therewith, the gas mixture is rectified in a dephlegmator. The dephlegmator has first and second sets of heat exchange passages which are in a heat exchange relationship with the gas mixture being rectified. A stream of a first heat exchange fluid is passed through a first of the set of heat exchange passages so as to condense some of the gas mixture. A stream of a second heat exchange fluid is sub-cooled by passage through a second set of the heat exchange passages.

Abstract: A container holder adapted to releaseably retain a plurality of similarly configured containers and adapted to permit release of each container individually.The holder is comprised of a central panel portion and a plurality of retaining portions. Each of the retaining portions has a pull tab that corresponds to it. The pull tab is joined to its respective retaining portion along the margin. The pull tab has a scoreline of a selected length proximate the pull tab so that the pull tab can be operated to release the loop-like structure thus preventing wildlife from becoming entangled in unruptured rings of plastic containers once the package is discarded.

Abstract: Compressed air is purified in apparatus 4 and passed through heat exchanger 6 in which it is reduced in temperature ready for rectification in a double column comprising a higher pressure rectification column 10 and a lower pressure rectification column 12 which are linked by a condenser-reboiler 14. The air is separated in the column 10 into oxygen-rich and nitrogen fractions. The oxygen-rich fraction is separated in the lower pressure column 12 into an oxygen and a lower pressure nitrogen product. Liquid nitrogen from the higher pressure column 10 is used as reflux in the lower pressure column 12, and a gaseous nitrogen stream is withdrawn from the column 10 as higher pressure nitrogen product. In order to compensate for the resulting loss of reflux in the column 12, a part of the lower pressure nitrogen product stream is compressed in compressor 38, cooled by passage through heat exchanger 6, and condensed in condenser 40. The resulting condensate provides additional reflux in the column 12.

Abstract: A method and apparatus for recovering work from a nitrogen stream, wherein the nitrogen is preheated via heat exchange with hot fluid from a chemical process, which process utilizes the oxygen product of the air separation. Preferably at least a part of the expanded nitrogen is utilized to preheat at least one fluid reactant of the chemical process. The chemical process may be gasification or direct reduction of iron oxide, as well as the conversion of natural gas into synthesis gas.

Abstract: Air is separated into oxygen and nitrogen in rectification columns 28 and 30. A stream of nitrogen is withdrawn from the top of the column 30 through an outlet 54, is warmed to about ambient temperature by passage through heat exchangers 34, 46 and 24, and is then heated at a pressure in the range 2 to 7 atmospheres absolute by heat exchange in heat exchanger 56 with a hot stream of fluid initially at a temperature of less than 600.degree. C. without said fluid undergoing a change of phase. The resulting hot nitrogen is then expanded in turbine 58 with the performance of external work, e.g. the generation of electricity.

Abstract: A method and apparatus for cryogenic air separation wherein both fuel gas and electrical power are produced. Respective operating pressures of the lower and higher pressure rectification columns can be set independently of one another, allowing flexibility in selecting the purity of the oxygen product.

Abstract: Purified air, typically at its dew point, is introduced into distillation column 10 through inlet 2. Oxygen-rich liquid is withdrawn through outlet 6 and is introduced into the top of a mixing column 20. Nitrogen-rich vapor passes from the top of the distillation column 10 to the bottom of the mixing column 20. In the mixing column, there is a downward flow of liquid that becomes progressively richer in nitrogen and an upward flow of vapor that becomes progressively richer in oxygen. Liquid nitrogen is withdrawn from the mixing column 20 through outlet 28 and is returned to the top of distillation column 10 to provide reflux therefor. In addition, a mixed stream comprising oxygen and nitrogen is withdrawn from the column 20 as product or waste. The mixing column 20 is provided with a first condenser 30 at its top and a second condenser 40 which takes a vapor stream from intermediate the outlet 28 and the top of the column 20 and returns condensed liquid to the column 20.

Abstract: A method and apparatus for the separation of air is described. Air is separated in a double distillation column comprising higher and lower pressure columns, an argon-enriched fluid stream is withdrawn from the lower column and separated in a further distillation column provided with liquid argon reflux from a condenser to yield an argon product. Liquid nitrogen is withdrawn from the high pressure column and reboiled in the condenser to form a gaseous stream. At least part of the gaseous stream is warmed and withdrawn. The withdrawn stream may be taken as product or expanded in a turbine to provide refrigeration.

Abstract: An improvement is provided in a process of separating air in a conventional double rectification column to produce oxygen and argon. In accordance with the invention, refrigeration is transfered to the oxygen-rich liquid conventionally formed in the higher pressure column from oxygen-poor liquid formed by condensing the oxygen-poor vapor formed in the higher pressure column. In addition, a portion of the oxygen-poor liquid is vaporized and either withdrawn as product or expanded in a turbine to provide refrigeration in the process.