Abstract: Described herein are systems and processes for precooling hydrogen or helium gas streams for liquefaction using liquid nitrogen having reduced energy consumption and amount of liquid nitrogen usage. The systems include a stream of pressurized liquid nitrogen, at least one turboexpander, and at least one heat exchanger.

Abstract: A method and apparatus for separating air in which a compressed and purified air stream is cooled in a main heat exchanger. Thereafter, the compressed and purified air is separated in a distillation column system to produce product streams. The product streams warm within the main heat exchanger by indirectly exchanging heat with the compressed and purified air stream. One or more of the product streams is distributed to a plurality of vortex tubes at successively warmer temperatures so that warm and cold streams produced thereby become successively warmer and one or more of the warm streams has a temperature warmer than that of said compressed and purified air stream upon its introduction into said main heat exchanger. All but the warm stream(s) having the warmer temperature are recycled back to said main heat exchanger to participate in the indirect heat exchange and heat is rejected by discharging said warm stream(s) so that heat is rejected at the warmer temperature and refrigeration is produced.

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 air separation process and apparatus employing a single column nitrogen generator. Part of the incoming air stream to be separated is expanded and combined with a waste stream. After partial warming of the combined stream, the combined stream is expanded and then utilized to liquefy part of the incoming air and for refrigeration purposes.

Abstract: A method and apparatus for producing a ultra-high purity oxygen product in which a nitrogen generator is operated to produce nitrogen and an oxygen rich fraction as column bottoms. Part of the oxygen rich fraction can be further processed at column pressure within rectification column to produce a tower overhead lean in hydrocarbons such as methane, acetylene, propane and propylene. After liquefaction in a head condenser of the rectification column, part of the condensate is further processed in a stripping column to produce an ultra-high purity liquid oxygen column bottoms which can be extracted as product.

Abstract: An air separation method and apparatus for producing nitrogen is provided in which oxygen enriched liquid, produced as a column bottoms of a distillation column, is partially vaporized and phase separated. The vapor phase is expanded to provide refrigeration while the liquid phase, after pressure reduction, is introduced into the head condenser to condense reflux to the column. Alternatively, part of the oxygen enriched liquid can be fully vaporized and then expanded to provide refrigeration. In such case, another part of the oxygen enriched liquid can be used to condense reflux to the column. Part of the air to be separated is liquefied against the oxygen enriched liquid to be vaporized and then introduced into a lower portion of the column to maintain production and purity levels that would have been obtained had all the oxygen enriched liquid stream been used in condensing reflux to the column.

Abstract: A cryogenic rectification method for producing a product stream from a gaseous mixture having higher and lower volatility components and heavy impurities. In accordance with the method, the mixture is separated by a cryogenic rectification process employing one or more columns having plates, trays or packing for intimately contacting ascending vapor and descending liquid streams within the column. The mixture to be separated after having been compressed is combined with the recycle stream to produce a combined stream which is purified in a prepurification unit that is designed to remove the heavy contaminants. The combined steam is divided into major and minor streams. The major stream is then cooled and separated into liquid and vapor phases. Heavy impurities concentrate in the liquid phase taken as the recycle stream, which is then pumped to a high enough pressure for vaporization of the impurities. The resulting vapor is then reduced in pressure and combined with the incoming gaseous mixture.

Abstract: An air separation method and apparatus in which air is separated by a low temperature rectification process having cooling and rectification stages for cooling air to a temperature suitable for its rectification and for distilling or fractionating the air into fractions enriched in components of the air, respectively. A process stream flowing between the cooling and distillation stages is either partially warmed or cooled and is then expanded in a turboexpander to produce a refrigerant stream. The refrigeration is recovered within the cooling stage and after the refrigerant stream has fully warmed, the refrigerant stream is drawn at subatmospheric pressure by a blower or the like and is then discharged at or above atmospheric pressure. The drawing of the air at subatmospheric pressure increases the turboexpander pressure ratio to in turn increase the amount of refrigeration that is supplied.

Abstract: A process and apparatus for producing a gaseous oxygen product at a delivery pressure so as to contain a low concentration of heavy impurities in which compressed and purified air is cooled in a main heat exchanger to near dew point temperatures and then introduced into an air separation unit designed to rectify the air into a liquid oxygen fraction. The air separation unit comprises high and low pressure columns operatively associated with one another in a heat transfer relationship by provision of a condenser-reboiler. The liquid phase of the air being separated becomes increasingly more concentrated in heavy impurities as it descends within the low pressure column so that liquid oxygen collected in the sump of the condenser-reboiler becomes concentrated in the heavy impurities and the liquid phase flowing into the sump contains a low concentration of the heavy impurities.

Abstract: A low temperature rectification process and apparatus in which a compressed gaseous mixture, for instance, air, is rectified to produce a lower volatility component in liquid form which is then pumped to a delivery pressure. After having been pumped, the lower volatility component is vaporized within a main heat exchanger. In order to effect the vaporization, a stream of the compressed gaseous mixture being cooled in the main heat exchanger is further compressed to form a further compressed stream. In order to minimize thermodynamic irreversibility within the main heat exchanger above a theoretical pinch point temperature thereof a portion of the further compressed stream is removed from the main heat exchanger at or near the theoretical pinch point temperature and then is still further compressed and introduced at a level of the main heat exchanger warmer temperature than the theoretical pinch point temperature.

Abstract: An air separation method for supplying gaseous oxygen to meet the requirements of a variable demand cycle. In accordance with present invention, air is rectified by a double column low temperature rectification process to produce a nitrogen rich vapor and liquid oxygen in high and low pressure columns. The nitrogen rich vapor and the liquid oxygen are withdrawn from the high and low pressure columns, respectively. The nitrogen rich vapor is partially heated within a main heat exchanger of the process and is then, turboexpanded to create plant refrigeration. When a demand for gaseous oxygen exists, a product stream formed of withdrawn liquid oxygen is pumped to delivery pressure and the nitrogen rich vapor is diverted within the main heat exchanger from being partially heated and expanded and is fully heated, compressed and then condensed against vaporizing the product stream to form the gaseous oxygen. The condensed nitrogen is then flashed into a flash tank.

Abstract: In order to provide `ultra high purity` nitrogen having diminished concentrations of light and heavy impurities in comparison with nitrogen produced by conventional cryogenic air separation, the nitrogen product from a conventional cryogenic air separation column is introduced into the bottom of a liquid-vapor contract column 2 fitted with a condenser 8 to provide reflux. A liquid nitrogen stream having a reduced concentration of heavy impurities is withdrawn from the column 2 through an outlet 22 situated at a level a few trays below the top tray in the column 2. The liquid nitrogen is then subjected to two stages of flash separation. In the first stage the liquid is passed through valve 24 into a phase separator 26. In the second stage, the resulting liquid from the first stage, having a reduced concentration of light impurities, is passed through valve 32 into a phase separator 34. Liquid nitrogen product is withdrawn from the phase separator 34 through outlet 38.

Abstract: Process for the recovery of nitrogen from air in which gaseous air is compressed, cooled and optionally purified in a heat exchanger, and then distilled to obtain pure gaseous nitrogen overhead and an oxygen enriched liquid bottoms, wherein all of the bottoms and a portion of the overhead is passed to a condenser to form an oxygen enriched gas and liquid nitrogen and wherein at least a portion of the oxygen enriched gas is compressed and recycled to the distillation column to enhance recovery of the nitrogen product.

Abstract: Method and Apparatus for separating a gaseous mixture into component gases wherein a portion of a compressed cooled stream of the gaseous mixture is substantially liquefied and respective portions sent to high and low pressure columns and either one of the gaseous components or a portion of the gaseous mixture is utilized for refrigeration from expansion with a portion of the work utilized for compression of the gaseous mixture.

Abstract: Argon and nitrogen are produced in a basic two step process. In a first step, oxygen is removed from a compressed air feed using low temperature PSA (pressure swing adsorption). In the second step, argon and nitrogen mixture is separated by cryogenic distillation. The process yields crude liquid argon and very high purity gaseous nitrogen.