Abstract: A mixed gas concentration regulating method and a concentration regulating apparatus, in which the maintenance of the recovery of an easily permeable gas and the restraint of the power expense are compatible.

Abstract: An object of the present invention is to provide a method for recovering a gas using a semipermeable membrane in an apparatus having a simple structure. The method is capable of maintaining a purity of a product gas at a constant value even if a feed amount of a feed stream is fluctuated. A feed stream G1 is a gas mixture of a fast gas having a relatively high permeability to a membrane 1 and a slow gas having a relatively low permeability to the membrane 1. The feed stream G1 is pressurized by a compressor 3 and fed to a membrane 1 separation unit 2 having the membrane 1. Part G7 of the permeate stream on the permeate side of the membrane 1 is recirculated to the upstream side of the compressor 3 through the first recirculation line 17 and merged into a stream of the feed stream G1. Simultaneously, another part of the permeate stream G2 on the permeate side of the membrane 1 is recovered through a product gas recovering line 5.

Abstract: A process for purifying argon to obtain a high-purity argon from argon gas containing at least nitrogen, carbon monoxide, oxygen, and methane, including a first step of adding air or oxygen to the argon gas in an amount sufficient to oxidize the contained carbon monoxide into carbon dioxide in the presence of a catalyst while maintaining a temperature sufficient to oxidize the contained carbon monoxide without substantially oxidizing the methane, a second step of adding hydrogen into the argon gas obtained in the first step and reacting the contained oxygen with the hydrogen into water in the presence of a catalyst, a third step of removing the carbon dioxide and the water from the argon gas obtained in the second step by use of an adsorbent, and a fourth step of cooling the argon gas obtained in the third step, introducing the argon thus cooled into a distillation column and performing distillation by use of a reflux containing argon as a main component to remove nitrogen, hydrogen, and methane, thereby reco

Abstract: There is provided a unit capable of simultaneously producing nitrogen of ra high purity and oxygen of ultra high purity from air as a feed material. Feed air is introduced into to the bottom 15 of a first rectification column 6. Liquid nitrogen of ultra high purity is recovered from between the upper rectifying part 12 and middle rectifying part 13, and liquid air free of high boiling point components is recovered from between the middle rectifying part 13 and lower rectifying part 14. Oxygen-rich liquid air collected in the bottom 15 is reduced in pressure by an expansion valve 31, and then introduced into a nitrogen condenser 8 as a refrigerant. After a portion of said liquid air is reduced in pressure by an expansion valve 33, it is introduced into the second rectification column 7, where low boiling point components are separated from the top part 21 and liquid oxygen of ultra high purity is recovered from the bottom 23.

Abstract: An air separation process wherein a nitrogen enriched fraction is withdrawn from the distillation column, a portion of which is compressed and recycled through the lowest positioned reboiler in the column and directed to an upper portion of the column as reflux.

Abstract: A process for producing gaseous nitrogen from a mixture to be treated in a distillation column, said mixture comprising nitrogen and oxygen, said process comprising the steps of:a) compressing the mixture to be treated to a pressure at least equal to the column pressure;b) cooling the compressed gas mixture and subjecting at least a first portion of said cooled mixture to expansion through a turbine to produce the required refrigeration and thereafter fractionated distillation in the column to obtain at the bottom of the column, an oxygen-enriched fraction and, at the top of the column, a nitrogen-enriched fraction,c) drawing off at least a portion of the nitrogen-enriched fraction as nitrogen product;d) compressing the remaining portion of the nitrogen-enriched fraction;e) recycling at least a portion of the compressed remaining portion of the nitrogen-enriched fraction to the bottom reboiler of the column where it condenses to provide reboil for the column;f) introducing at least a portion of the condensed

Abstract: The invention concerns the separation of air with an external cold source. An internal cold source is provided to supply cold heat to a compressed inert gas by expansion of a part of a liquefied inert gas when the cold from the external cold source proves to be insufficient. This part of the liquefied inert gas is combined with recycling and compressed gases. The desired production of liquid oxygen and nitrogen is thus assured in spite of variations in the external cold source.