Abstract: An air separation unit and associated method for separating air by cryogenic distillation using a distillation column system including a higher pressure column, a lower pressure column, an intermediate pressure kettle column, and an argon column arrangement is provided. The disclosed air separation unit and method is particularly suited for production of high purity nitrogen for electronics applications and includes nitrogen recycle circuit necessary to attain the higher purity nitrogen products. In addition to the intermediate pressure kettle column, the present air separation unit and associated method employs a once-through argon condenser, preferably disposed within the lower pressure column as well as a once-through kettle column reboiler, a once-through kettle column condenser.

Abstract: A method and apparatus for the production of air gases by the cryogenic separation of air with front end purification and air compression can include using an available compressed dry gas such as nitrogen, oxygen, stored purified air, or synthetic air to repressurize the adsorber without diverting any of the purified air just exiting the currently on-line adsorber or changing the flow rate of the main air compressor or air sent to the cold box. This enables the main air compressor (MAC) to operate at a relatively constant flow rate while also sending a relatively constant air flow to the cold box during this repressurization step, thereby reducing the risks of process upsets and minimizing capital expenditures related to the MAC and other warm-end equipments.

Abstract: A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having an argon rejection column and a reflux type argon condenser disposed internally within the lower pressure column. An impure argon stream is subsequently recovered from the argon rejection column and purified within an integrated adsorbent based argon refining and purification subsystem to produce product grade argon. The waste stream from the adsorbent based argon refining and purification subsystem is recycled back to the argon rejection column so as to improve the argon recovery.

Abstract: Method and apparatus of separating a nitrogen from a compressed and purified feed stream in a cryogenic rectification plant that employs a distillation column to produce a nitrogen-rich vapor as a column overhead and an oxygen-rich liquid column bottoms. Reflux is generated for the column by condensing part of the nitrogen-rich vapor within a down-flow heat exchanger. A stream of the oxygen-rich liquid column bottoms is introduced into an ejector which draws a stream of an oxygen-rich liquid phase produced from the outlet of a down-flow heat exchanger. The combined oxygen-rich liquid exiting the ejector is fed to the down-flow heat exchanger to condense the nitrogen-rich vapor. In such manner, part of the oxygen-rich liquid phase is recirculated to prevent dry-out of the down-flow heat exchanger outlet and to maintain effective condensation of the nitrogen-rich vapor.

Abstract: Air separation method in which air is separated within cryogenic rectification processes conducted in first and second cryogenic air separation plants. The first cryogenic air separation plant is designed to produce an oxygen-rich product stream and the second cryogenic air separation plant is designed to produce an impure oxygen vapor stream. At least part of the impure oxygen vapor stream is introduced into a lower pressure column of the first cryogenic air separation plant and oxygen contained in such stream along with air separated within the first air separation plant is used in producing the oxygen-rich product stream.

Abstract: A process for carrying out cryogenic air separation wherein liquid oxygen is pressurized and vaporized against condensing feed air to produce oxygen gas product wherein excess plant refrigeration is generated such that the aggregate warm end temperature difference of the process exceeds the minimum internal temperature difference of the primary heat exchanger by at least 2 K.

Abstract: Methods and apparatus for air separation by cryogenic distillation in a double or triple air separation column. The column in the system with the highest operating pressure is said to be operating at medium pressure. All the air to be distilled is pressurized to a high pressure, which is about 5 bar greater than the medium pressure. The air is purified at this high pressure, and a portion of the purified air is cooled in a heat exchange line, while another portion is expanded in a turbine. Part of the cooled air is drawn from the exchange line with a cold booster, which is mechanically coupled to at least one turbine. An energy dissipation device is also provided which is coupled to the turbine not coupled to the cold booster. The energy dissipation device is either another booster, an oil break system, or an electrical generator.

Abstract: The invention relates to a method for the provision of gas under pressure, by vaporisation of a cryogenic liquid from at least two cryogenic separation devices (A, B, C, D). Each device comprises a heat exchanger (1) and a system of columns (2, 3). In a first mode of operation, a cryogenic liquid is withdrawn from the columns in each cryogenic separation device, at least a part of which is pressurised (7, 8) to give a pressurised cryogenic liquid (9) and at least a part of the cryogenic liquid under pressure is vaporised in the heat exchanger (1) to give a part of gas under pressure (10). A cryogenic liquid is sent (6) from the cryogenic separation device to a common store (12) and at least one liquid (28A, 28B, 28C, 28D) coming from the store is vaporised in the exchange line (1) in at least one of the cryogenic separation devices.

Abstract: Systems and methods are disclosed for a gas production system to efficiently maintain a pressure of a gaseous output stream within a tight pressure range when the system changes normal operation to backup operation. In one preferred embodiment, during normal operation a backup vaporizer is kept in cold standby by directing a small portion of a liquefied gas stream away from the main heat exchanger to the backup vaporizer. In this way, the backup vaporizer is able to respond immediately to a shutdown of the main gas production system. During normal operation, the output of the backup vaporizer is recombined with the gaseous output stream to any avoid loss of product thereby increasing efficiency.

Abstract: A cryogenic air separation plant and method of operation wherein, after an interruption in operation, liquid from the sump of a lower pressure column and liquid from the sump of a higher pressure column is passed to a condenser, preferably an argon column top condenser, prior to the restarting of the plant.

Abstract: A low temperature air separation process and apparatus for producing pressurized gaseous product in an air separation unit using a system of distillation columns which include cooling a compressed air stream in a heat exchange line to form a compressed cooled air stream, sending at least part of the compressed, cooled air stream to a column of the system, liquefying a process stream to form a first liquid product, storing at least part of the first liquid product in a storage tank, sending at least part of the above first liquid product from the storage tank to the air separation unit as one of the feeds, extracting at least one second liquid product stream from a column of the column system and pressurizing the at least one second liquid product stream, vaporizing the above pressurized second liquid product stream to form pressurized gaseous product in the heat exchange line and extracting a cold gas without warming it completely in the heat exchange line.

Abstract: A combined main air/O2 enriched product compressor for use with an air separation unit that produces O2 enriched product is provided that includes a prime mover that drives a bull gear. The bull gear drives at least two pinion gears, and the pinion gears drive several compression stages where at least one compression stage compresses feed air for the air separation unit and at least one compressor stage compresses O2 enriched product from the air separation unit. The combined main air/O2 enriched product compressor satisfies all air separation unit feed air requirements and at least some compression for the oxygen product from the air separation unit. A method is also provided.

Abstract: A cryogenic air separation process wherein one or more pressurized product streams enriched in oxygen, nitrogen and argon are produced by cryogenic distillation. One or more of the product streams are pressurized above the operating pressure of the distillation column by introducing a pressurizing fluid into a vessel containing a lower pressure product liquid. In the design of the system the pressurizing fluid can be air or streams enriched in oxygen, nitrogen or argon. Product stream pressurization is accomplished without the use of mechanical pumping devices.

Abstract: A cryogenic air separation system particularly useful for producing elevated pressure product wherein additional reflux is generated by a heat pump circuit operating between the upper portion and an intermediate location of the lower pressure column of a double column.

Abstract: For producing ultrapure nitrogen by low-temperature fractionation of air in a rectification system having at least one rectification column, compressed and purified feed air is conducted into a high pressure column, an oxygen-free pressurized nitrogen fraction is produced from the high pressure column, conducted into a low-pressure column and in the low-pressure column carbon-monoxide-free low-pressure nitrogen is produced as overhead gas. The oxygen-free pressurized nitrogen fraction (1) is either taken off in the liquid state from an upper region of the high pressure column or is provided from a liquid tank (22) containing stored oxygen-free nitrogen and the oxygen-free pressurized nitrogen fraction (1) is expanded into the bottom-heated low-pressure column (2).

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: A system for producing enriched air wherein a multistage compressor is integrated with a cryogenic air separation plant and serves to compress feed air for the plant while also compressing both air and oxygen fluid from the plant to produce the enriched air.

Abstract: A method and apparatus of separating air to produce an oxygen product. In accordance with the method and apparatus the air is rectified within a double column arrangement. The lower pressure column has lower and intermediate reboilers. Nitrogen from the higher pressure column is compressed and sent to the lower reboiler and oxygen tower overhead from the higher pressure column is fed to the intermediate reboiler. The resultant liquid is used to reflux both columns. The advantages in the arrangement set forth above is that the higher pressure column may be made to operate at a lower pressure to conserve energy.

Abstract: A cryogenic rotary pump for pressurizing a flow of a cryogenic liquid and for dividing the flow into a first lower pressure and a second higher pressure stream has a series of pumping chambers. A single rotary drive shaft carries a rotary inducer located in the chamber, a first impeller in the chamber, and a second impeller in the chamber. A liquid receiving chamber is located intermediate the pumping chambers. A first outlet from the pump for the first lower pressure stream is contiguous to the chamber and a second outlet is provided for the second higher pressure stream. The pump may serve to pressurize a flow of unboiled liquid oxygen from a sump of a lower pressure column of a double column also having a higher pressure column.

Abstract: Air is separated in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a first condenser-reboiler, of which the condensing passages communicate with an upper region of the higher pressure rectification column, and the reboiling passage communicate with a lower region of the lower pressure rectification column. A second condenser-reboiler is operated so as to reboil a liquid fraction obtained in the higher pressure rectification column. A stream of the air to be separated is partially or totally condensed by indirect heat exchange with a stream of nitrogen condensed in the first condenser-reboiler. At least part of the stream of condensed nitrogen is taken as product downstream of its heat exchange with the second stream of compressed air.

Abstract: An air separation plant includes an air compressor, a gas turbine arranged to drive the air compressor, a product nitrogen compressor, and a steam turbine arranged to drive the product nitrogen compressor. The steam turbine forms part of a circuit including a steam generator in which stream is able to be raised by heat exchange of water with hot gaseous exhaust from the gas turbine or another gas turbine.

Abstract: A process and a system for the low-temperature separation of air by rectification is provided. A liquid fraction is obtained in a rectifying system, stored in a tank and at least a portion of the liquid fraction taken out of the tank and brought to an increased pressure. During normal operation, the liquid fraction, which was brought to an increased pressure, is heated in a preheat exchanger and evaporated in the main heat exchanger. During an operating disturbance, at least a portion of the liquid product is removed from the tank, evaporated and used for an emergency supply.

Abstract: A system for the production of ultra-high purity nitrogen and ultra-high purity oxygen at high recovery by the cryogenic rectification of feed air employing a main column, an auxiliary column and a stripping column, wherein the stripping column is driven by main column kettle fluid and additional process fluid generated in the auxiliary column is utilized in the main column.

Abstract: A serial column system for producing relatively large quantities of both high purity nitrogen gas and high purity nitrogen liquid using a first column producing the high purity gas and a second column producing the high purity liquid, with second column top fluid refluxing the first column.

Abstract: Air is separated in an arrangement of rectification columns comprising a double rectification column (which has a higher pressure column and a lower pressure column), an intermediate pressure rectification column and a side rectification column communicating with the lower pressure column. The side rectification column is provided with a condenser and the intermediate pressure rectification column with a reboiler and a condenser. A stream of oxygen-enriched liquid and a stream of liquid air are withdrawn from the higher pressure column through outlets and are separated in the intermediate pressure rectification column. The reboiler is heated by a stream typically withdrawn from the side rectification column through an outlet. A stream of liquid is withdrawn through an outlet at the bottom of the intermediate pressure rectification column is used to cool the condenser and is separated in the lower pressure rectification column.

Abstract: An air stream is compressed and divided into a first partial stream (4) used as the feed air stream for a low-temperature air rectification system (16), and a second partial stream (5) used as an oxidation agent in a chemical reaction (6). The waste gas from the chemical reaction is work expanded (9). The first partial stream (4) is introduced into one of rectifying columns (17, 18). A liquid product stream is withdrawn from one (18) of the rectification columns, compressed (28) and vaporized against a further compressed (31, 33) process stream (15) from the low-temperature rectification. At least a portion of the mechanical energy resulting from the work expansion (9) of the waste gas of chemical reaction (6) is used for further compression (31, 33) of the process stream.

Abstract: Air is separated in an arrangement of rectification columns comprising a double rectification column (which has a higher pressure column and a lower pressure column), an intermediate pressure rectification column, and a side rectification column communicating with the lower pressure column. The side rectification column is provided with a condenser, and the intermediate pressure rectification column with a reboiler and a further condenser. A stream of oxygen-enriched liquid is withdrawn from the bottom of the higher pressure column through an outlet and is separated in the intermediate pressure rectification column. The reboiler is heated by a stream typically withdrawn from the side rectification column through an outlet. A stream of liquid is withdrawn from the bottom of the intermediate pressure rectification column, is employed to cool the further condenser of the intermediate pressure rectification column, and is partially vaporised therein.

Abstract: An apparatus and method involving the use of a multi-column system in which higher and lower pressure columns are operatively associated with one another by a condenser-reboiler. A pump is provided for pumping a stream of sump liquid of the lower pressure column to produce a pressurized product. The condenser-reboiler is a falling film type of heat exchanger in which liquid is vaporized to produce boilup in the lower pressure column against vaporizing tower overhead in the higher pressure column to reflux both of the columns. Liquid is recirculated back to the condenser-reboiler by an ejector that uses part of a pumped stream as the motive fluid to draw liquid for recirculation. In such manner, less energy is consumed in the recirculation than had all of the recirculated liquid been pumped. Furthermore, an ejector, unlike a second pump used for recirculation purposes, is a solid state device with no moving parts.

Abstract: An installation for the production of argon comprising a double column (1, 3) and an argon purification column (5). An auxiliary column (9) serves to effect the nitrogen-oxygen separation, and is supplied by a stream from the low pressure column (3). Therefore, nitrogen does not contaminate the stream sent to the argon purification column (5).

Abstract: A stream of precooled and purified air is introduced into a double rectification column comprising a higher pressure rectification column and a lower pressure rectification column and is separated therein into an oxygen-rich fraction and a nitrogen-rich fraction. A stream of argon-enriched oxygen vapor flows from an outlet of the lower pressure rectification column into a side column in which argon is separated therefrom. An oxygen-enriched liquid air stream is taken from an outlet at the bottom of the higher pressure rectification column. A vaporous oxygen-enriched air stream is introduced into the lower pressure rectification column through an inlet above the outlet. At least part of the oxygen-enriched liquid is separated in a further or intermediate pressure rectification column provided with a reboiler, thereby forming a vapor depleted of oxygen and a liquid air stream further enriched in oxygen.

Abstract: A process is set forth for the cryogenic distillation of an air feed to produce high pressure nitrogen of various purity, varying from moderately high purity (99.9% nitrogen) to ultra-high purity (less than 1 part per billion of oxygen). The process is particularly suited for cases where the high pressure nitrogen is needed directly from the distillation column system to avoid contamination concerns associated with compressing nitrogen that is produced at lower pressures. The process uses a high pressure column, which operates at a pressure to directly produce the nitrogen at the desired high pressure, and one or more lower pressure columns which produces a portion of the nitrogen product at a lower pressure. At least a portion of the lower pressure nitrogen is compressed and fed to the high pressure column at a location which is below the removal location of the high pressure nitrogen.

Abstract: A high pressure combustion turbine is integrated with a double column cryogenic air separation system by cooling and purifying a portion of the compressed air from the combustion turbine compressor, work expanding a first portion of the resulting cooled air, and introducing the expanded air into the low pressure column. A second portion of the resulting cooled air is further cooled, throttled, and introduced into the high pressure column. A nitrogen product stream is returned to the turbine combustor, and a portion of the nitrogen product stream optionally is cooled, throttled, and recycled into the high pressure column. Preferably the higher pressure column operates at an absolute pressure which is about 20% to about 85% of the absolute pressure of the compressed air from the combustion turbine air compressor.

Abstract: A cryogenic rectification system for producing gaseous oxygen and high purity nitrogen employing a double column and an auxiliary column which processes higher pressure column fluid.

Abstract: Air is compressed in a compressor, cooled in a main heat exchanger, partially condensed in a reboiler-condenser, introduced into a higher pressure rectifier, and separated therein into nitrogen and oxygen-enriched liquid. Resulting nitrogen is condensed in further reboiler-condensers. One part of the condensate is used as reflux in the higher pressure rectifier and another part as reflux in a lower pressure rectifier. A stream of oxygen-enriched liquid is withdrawn from the high pressure rectifier and sent to an intermediate pressure rectifier which is reboiled by one of the further reboiler-condensers and in which further nitrogen is separated. A stream of liquid further enriched in oxygen is withdrawn from the bottom of the intermediate pressure rectifier and is separated in the lower pressure rectifier and impure and pure oxygen products are withdrawn respectively therefrom.

Abstract: Cooled and purified air is introduced into a higher pressure rectifier in at least partly vaporous state and is separated therein into oxygen-enriched liquid air and nitrogen. One part of the nitrogen so separated is condensed in a reboiler-condenser and another part in a reboiler-condenser. Some of the condensate is used as reflux in the high pressure rectifier, and the rest of the condensate as reflux in a lower pressure rectifier. Oxygen-enriched liquid air is taken from the bottom of the higher pressure rectifier and is separated into oxygen and nitrogen in the lower pressure rectifier. A liquid argon-enriched oxygen stream is withdrawn from the lower pressure rectifier through an outlet and is separated into argon and oxygen fractions in a further rectifier. The further rectifier is reboiled by the reboiler-condenser.