Abstract: A device for separating a gas, such as air, into components, includes a plurality of modules, each module having one or more polymeric membranes capable of gas separation. A set of valves, pipes, and manifolds together arrange the modules in one of two possible configurations. In a first configuration, the modules are arranged in parallel. In a second configuration, the modules are divided into two groups which are arranged in series. The device can be switched from parallel to series, or from series to parallel, simply by changing the positions of a small number of valves, typically three valves. The device can therefore produce gas either of higher purity, or moderate purity, depending on the settings of the valves. The device also includes improved structures for connecting the modules to inlet and outlet manifolds, and also includes devices for temporarily isolating one or more modules from the system.

Abstract: A cartridge for non-cryogenically separating a gas into components includes a plurality of hollow polymeric fibers, the fibers being anchored by a pair of tubesheets, each tubesheet being adjacent to a head, the tubesheet and head being joined by a clamshell retainer. The cartridge does not have a core tube. The fibers are enclosed within a sleeve, the sleeve being sufficiently thin so as to be a non-structural element. The cartridge may be inserted within a larger pressure vessel. The cartridge of the present invention can accommodate more fibers than comparable cartridges of the prior art, and therefore has greater throughput.

Abstract: A gas separation module includes hollow polymeric fibers held between a pair of tubesheets. The tubesheets are mounted to a core tube, and the distance between the tubesheets is maintained constant. The core tube is formed in telescoping sections, such that the fibers are attached to the tubesheets when the core tube is in its extended position, and the core tube is then collapsed, forming slack in the fibers. The core tube includes two distinct channels, connected to receive permeate and retentate gas streams, and to carry these streams to outlet ports while keeping the streams separate. Because the tubesheets are affixed to the core tube, the tubesheets do not move under the influence of gas pressure in the module. The slack in the fibers compensates for shrinkage of the fibers, prolonging the life of the module.

Abstract: A two-stage gas-separation membrane system includes two identical membrane modules held within a single casing. A feed gas is directed into the first module, so as to produce permeate and retentate streams. One of the latter streams then becomes the feed gas for the second module, and reaches the second module through a core tube located within the module. The product of the second module is the product gas for the system. The gas streams entering the two modules flow in mutually opposite directions. This arrangement makes it feasible to provide a two-stage system while using only the number of ports that would be needed for a single stage.

Abstract: An air dehydration module includes polymeric fibers for separating water vapor from air, and also includes a carbon filter material, positioned at an outlet end of the module, and within the same pressure vessel which houses the fibers. The module may generate its own sweep stream, in which case a portion of its output is directed to flow through an orifice, towards the inlet end of the module. In an alternative embodiment, the sweep gas is produced by a distinct gas-separation module, which receives an input stream from the output of the dehydration module. The dehydration module produces clean and dry air which can be used as is, or as an input stream to an air separation module.

Abstract: A device for separating a gas, such as air, into components, includes a plurality of modules, each module having one or more polymeric membranes capable of gas separation. A set of valves, pipes, and manifolds together arrange the modules in one of two possible configurations. In a first configuration, the modules are arranged in parallel. In a second configuration, the modules are divided into two groups which are arranged in series. The device can be switched from parallel to series, or from series to parallel, simply by changing the positions of a small number of valves, typically three valves. The device can therefore produce gas either of higher purity, or moderate purity, depending on the settings of the valves.

Abstract: A multi-stage polymeric membrane module system separates a gas, such as air, into components of high purity. In at least two of the stages, a portion of the retentate gas is directed into the low-pressure side of the module, to act as a sweep gas. The use of the sweep gas reduces the partial pressure of permeate gas on the low-pressure side of the membrane, and therefore improves the flow of permeate through the membrane. In a preferred embodiment, there are three modules. The output streams are taken from the retentate outlet of one module, and from the permeate outlet of another module. The output streams have very high purity, relative to the number of modules required, as compared with systems of the prior art.

Abstract: A polymeric fiber for use in gas separation is formed from a spin dope which includes solvent and non-solvent materials. The fiber is passed through a quench bath, and then a leach bath, in which the solvent and non-solvent are removed. The quench bath and the leach bath include sets of rollers which transport the fiber through the system. Each set of rollers in the leach bath operates at a speed which is greater than or equal to the speed of the rollers which are immediately upstream. Thus, the fiber is stretched, in different amounts, at the same time that the solvent and non-solvent are being removed, and while the fiber is still wet. The resulting fiber has been found to exhibit superior flux and selectivity properties.

Abstract: A module having polymeric gas-separation membranes is capable of operation in extreme temperature environments. In one embodiment, the module includes polymeric fiber membranes, a tubesheet for holding the membranes, and a sleeve encasing the membranes, all of which are made of materials having coefficients of thermal expansion which differ from each other by not more than about 10%. In another embodiment, the membranes, the tubesheet, and the sleeve are all made of materials having a glass transition temperature greater than a highest anticipated temperature of operation of the module. In another embodiment, the module includes a head, and a clamshell having multiple protrusions which engage corresponding grooves in the head and in at least two grooves formed in the tubesheet.

Abstract: A gaseous component is extracted non-cryogenically from a feed gas containing condensable hydrocarbons. The feed gas is passed first through a module containing polymeric fibers useful for removing water vapor from the gas. The gas is then passed through a module containing polymeric fibers selected such that they remove some, but not all, of the carbon dioxide in the stream. The gas is then passed through a module containing polymeric fibers selected to remove at least some of the remaining carbon dioxide as well as heavy hydrocarbons, defined as C5 and heavier, from the stream. The invention is especially useful in processing raw methane taken from a well, and in producing methane which is relatively free of water vapor, carbon dioxide, and heavy hydrocarbons.

Abstract: A composition for making polymeric fiber membranes, for use in non-cryogenic separation of gases, substantially improves product flow, with only a small decrease in the recovery ratio. The composition is a spin dope including tetrabromo bis-phenol A polycarbonate (TBBA-PC) and tetrabromo bishydroxyphenylfluorene polycarbonate (TBBHPF-PC), in proportions, by weight, ranging (in percent) from about 60/40 to 40/60, and n-methyl pyrrolidinone (NMP) and triethylene glycol (TEG), wherein the ratio of the amounts of NMP to TEG, by weight, is in the range of about 1.6-2.5. The spin dope is used to make hollow fibers for use in gas-separation membrane modules.

Abstract: A polymeric fiber for use in gas separation is formed from a spin dope which includes solvent and non-solvent materials. The fiber is passed through a quench bath, and then a leach bath, in which the solvent and non-solvent are removed. The quench bath and the leach bath include sets of rollers which transport the fiber through the system. Each set of rollers in the leach bath operates at a speed which is greater than or equal to the speed of the rollers which are immediately upstream. Thus, the fiber is stretched, in different amounts, at the same time that the solvent and non-solvent are being removed, and while the fiber is still wet. The resulting fiber has been found to exhibit superior flux and selectivity properties.

Abstract: A gaseous component is extracted non-cryogenically from a feed gas containing condensable hydrocarbons. The feed gas is passed first through a module containing polymeric fibers useful for removing water vapor from the gas. The gas is then passed through a module containing polymeric fibers selected such that they remove some, but not all, of the carbon dioxide in the stream. The gas is then passed through a module containing polymeric fibers selected to remove at least some of the remaining carbon dioxide as well as heavy hydrocarbons, defined as C5 and heavier, from the stream. The invention is especially useful in processing raw methane taken from a well, and in producing methane which is relatively free of water vapor, carbon dioxide, and heavy hydrocarbons.

Abstract: A composition for making polymeric fiber membranes, for use in non-cryogenic separation of gases, substantially improves product flow, with only a small decrease in the recovery ratio. The composition is a spin dope including tetrabromo bis-phenol A polycarbonate (TBBA-PC) and tetrabromo bishydroxyphenylfluorene polycarbonate (TBBHPF-PC), in proportions, by weight, ranging (in percent) from about 60/40 to 40/60, and n-methyl pyrrolidinone (NMP) and triethylene glycol (TEG), wherein the ratio of the amounts of NMP to TEG, by weight, is in the range of about 1.6-2.5. The spin dope is used to make hollow fibers for use in gas-separation membrane modules.

Abstract: A non-cryogenic system for gas separation includes an absorbent system for removing condensable hydrocarbons from a feed gas. The feed gas is then directed into a gas-separation membrane. The absorbent system includes a liquid absorbent having an affinity for hydrocarbons. The liquid absorbent can be, for example, compressor oil or mineral oil. A chiller and a carbon bed may optionally be positioned between the absorbent system and the membrane. The absorbent is periodically regenerated by reducing the pressure or increasing the temperature of the liquid.

Abstract: An air dehydration membrane module is provided with a sweep gas which is taken from the waste gas of a pressure swing adsorption (PSA) unit. No additional compressor is required, other than the compressor forming part of the PSA unit. In another embodiment, the sweep gas includes the combination of dried product gas, taken from the dehydration membrane module, and a supplemental gas, which may be ambient air, or permeate gas from an air separation membrane, or waste gas from a PSA unit. An air ejector combines the streams, without the use of an additional compression step, and the combined gas is used as a sweep stream for the dehydration module. The invention also includes the method of selecting an optimum point at which the sweep gas is injected into the module.

Abstract: An air dehydration membrane module is provided with a sweep gas which is taken from the waste gas of a pressure swing adsorption (PSA) unit. No additional compressor is required, other than the compressor forming part of the PSA unit. In another embodiment, the sweep gas includes the combination of dried product gas, taken from the dehydration membrane module, and a supplemental gas, which may be ambient air, or permeate gas from an air separation membrane, or waste gas from a PSA unit. An air ejector combines the streams, without the use of an additional compression step, and the combined gas is used as a sweep stream for the dehydration module. The invention also includes the method of selecting an optimum point at which the sweep gas is injected into the module.

Abstract: An integrated fiber membrane module for air dehydration and air separation includes dehydration and separation units disposed concentrically in a generally cylindrical module. Air flows through the outer dehydration unit, becomes dried, and is then directed, in an opposite direction, through the separation unit. The permeate gas from the separation unit serves as a sweep gas for the dehydration unit. A portion of dried gas produced by the dehydration unit may be used as a sweep gas for the separation unit, and also for the dehydration unit. The module makes it feasible to dry and separate air using a device which occupies relatively little space, and which is therefore especially suited for use in aircraft and in other cramped environments.

Abstract: A shipboard system provides dry, oil-free utility air and inert gas for use on a marine vessel. A compressor converts ambient air into a pressurized air stream. The air stream is cooled by heat exchange with sea water in the vicinity of the vessel. The air stream is then dried in a dehydration membrane module, and some of the product of the dehydration module is taken for use as utility air. The remainder of the dried air is passed through an air separation module which includes a polymeric membrane. The product of the air separation module includes a nitrogen-enriched gas which is used as an inert gas on the vessel. The compressor is the only mechanically moving component of the system.

Abstract: Water is removed from a natural gas well by the use of nitrogen, which is produced by a non-cryogenic unit at the site of the well. A cylindrical casing is positioned over the well. A tubing, disposed within the casing, is aligned over the well bore. Nitrogen is selectively introduced into either the space between the tubing and the casing, or into the tubing, so as to displace water from within the tubing or the casing, respectively. The water is directed to a storage tank at the site of the well. Nitrogen is purged from the lines, and the well is ready to resume production.