Abstract: The use of solutions of organic polymers for production of carbon membranes suitable for gas separation, and a process for producing carbon membranes suitable for gas separation, comprising the steps of a) coating a porous substrate with solutions of organic polymers, b) drying the polyester coating on the porous substrate by removing the solvent, and c) pyrolyzing the polyester coating on the porous substrate to form the carbon membrane suitable for gas separation, it being possible to conduct any of steps a) to c) or the sequence of steps a) to c) more than once.

Abstract: A membrane cartridge is manufactured by repeatedly folding and joining two strips of membrane to form a cross-pleated cartridge with a stack of openings or fluid passageways configured in an alternating cross-flow arrangement. The cartridge can be modified for other flow configurations including co-flow and counter-flow arrangements. Methods for manufacturing such cross-pleated membrane cartridges, as well as apparatus used in the manufacturing process are described. Cross-pleated membrane cartridges comprising water-permeable membranes can be used in a variety of applications, including in heat and water vapor exchangers. In particular they can be incorporated into energy recovery ventilators (ERVs) for exchanging heat and water vapor between air streams being directed into and out of buildings.

Abstract: A gas separation unit 102, 200, 300 for permeating a gas out from a pressurized feed mixture includes an input manifold 104, 204, an exhaust manifold, 106, 206 and a permeate assembly 108, 208, 303. The permeate assembly supports one or more permselective foils 130, 132, 218, 232, 318 over a hollow cavity 134, 272, 306 supported by a microscreen element 142, 144, 228, 230, 326. The microscreen element includes non-porous perimeter walls 190, 192, 278 supported on a frame surface and a porous central area 194, 280 supported over the hollow cavity. A porous spacer 138, 140, 174, 234 disposed inside the hollow cavity structurally supports the entire microscreen surface spanning the hollow cavity while also providing a void volume for receiving fluid passing through the porous central area and for conveying the fluid through the hollow cavity.

Abstract: The growth of continuous MOF membranes on porous polymeric supports is reported, wherein a dip-coating procedure is used to deposit a layer of seed MOF nanocrystals on the surfaces of porous polymers, preferably in the form of hollow fibers, and polycrystalline MOF membranes are subsequently grown at temperatures as low as 65° C. from precursor solutions. The present work opens the road to inexpensive and scalable fabrication of MOF membranes for large-scale separation applications.

Abstract: A method and apparatus for humidifying residential and commercial buildings in which a flue gas generated by a residential or commercial furnace is provided to one side of a porous liquid water transport membrane and habitable space air is provided to an opposite side of the porous liquid water transport membrane in an amount sufficient to provide a habitable space air to flue gas volume flow rate ratio of at least 8.3:1. At least a portion of the water vapor in the flue gas is condensed, providing condensed liquid water which is passed through the porous liquid water transport membrane to the habitable space air side of the porous liquid water transport membrane. On the habitable space air side of the membrane, the condensed liquid water is evaporated into the habitable space air, producing humidified habitable space air which is provided to the rooms of the residential and commercial buildings. Beneficially, no supplemental water source is required for the humidification process.

Abstract: A method of forming a gas separation membrane including: depositing a first hydrophilic polymer solution; depositing on top of the first hydrophilic polymer solution a second, different hydrophilic polymer solution, thereby forming a two-layer polymer solution; forming the two-layer polymer solution into one of a forward osmosis membrane and a pressure retarded osmosis membrane by bringing the second, different hydrophilic polymer solution into contact with water to form the dense layer; coating one of the forward osmosis membrane and the pressure retarded osmosis membrane with a thin layer of a third, different, hydrophilic polymer more pH tolerant than the first and second hydrophilic polymer solutions to form a dense rejection layer thereon; and exposing one of the coated forward osmosis membrane and the coated pressure retarded osmosis membrane to a high pH solution. A gas separation membrane formed from the foregoing process.

Abstract: A bypass unit for a water vapor transfer assembly includes a main body, a check valve, and an adjustable flow regulator. The main body has a conduit formed therethrough. The check valve is in communication with the conduit. The check valve normally militates against a flow of a bypass stream through the conduit and permits the flow of the bypass stream through the conduit above a threshold flow rate. The flow regulator is in communication with the conduit. The flow regulator permits an adjustment of the flow of the bypass stream to modify the water transfer rate of the water transfer assembly.

Abstract: A method of making a crystalline silicoaluminophosphate-34 (SAPO-34) membrane. The method comprises the steps of providing a porous support having a pore size distribution such that a small proportion of its pores are larger than 10 microns, seeding the porous support with SAPO-34 seed crystals by capillary suspension infiltration to give a seeded support, and growing a SAPO-34 membrane layer on the surface of the seeded support.

Abstract: A gas separation device comprising a porous support structure comprising polymeric hollow fibers, and an inorganic mesoporous membrane disposed on the porous support structure is disclosed. The inorganic mesoporous membrane is uniform and free of defects. Further, the inorganic mesoporous membrane comprises a network of interconnected three-dimensional pores that interconnect with the porous support structure. The gas permeances of the inorganic mesoporous membrane is substantially higher than the gas permeances of the polymeric hollow fibers. A method of fabricating the gas separation device is also disclosed.

Abstract: Disclosed is an exhaust gas treating system having an exhaust gas treating apparatus for carbon dioxide capture process which additionally removes harmful substances remaining in the gas discharged from the existing flue-gas desulfurization process by using separation membrane so as to efficiently carry out the carbon dioxide capture process. The exhaust gas treating system using polymer membrane, comprises a carbon dioxide capture equipment for capturing carbon dioxide from the exhaust gas of a boiler, a flue-gas denitrification equipment placed between the boiler and the carbon dioxide capture equipment, a dust-collecting equipment and a flue-gas desulfurization equipment.

Abstract: A pleatable, high efficiency composite gas filtration media is provided. The media includes an essentially boron free chopped strand glass backer layer and media layer comprising a synthetic material. The composite media exhibits excellent pleatability, low boron out gassing, and low organic out gassing, with filtration performance comparable to existing commercial membrane composites.

Abstract: The present disclosure describes a method for forming microporous membranes. More specifically, vapor induced phase separation techniques are used for forming multizone microporous membranes having improved material throughput.

Abstract: An apparatus and process is taught for the formation of ethanol from a fermentation medium in the absence of an ethanol concentration distillation step.

Abstract: Provided is a power plant for generating electrical energy comprising a combustion chamber for producing steam, at least one downstream flue gas purification stage, a separation stage for CO2, a recycling circuit for the flue gas, and a high-temperature O2 membrane, which is connected upstream of the combustion chamber. The high-temperature O2 membrane has an inlet and an outlet on the feed side which are thermally coupled by way of a heat exchanger. On the permeate side, the high-temperature O2 membrane has only an outlet which is connected to the combustion chamber and/or the flue gas recycling circuit and a means for cooling and/or compression which is disposed in this outlet.

Abstract: The present disclosure relates to a system for carbon dioxide separation. The system includes a conducting membrane having two phases. The first phase is a solid oxide porous substrate. The second phase is molten carbonate. The second phase is positioned within the solid oxide porous substrate of the first phase. The system also includes a H2 and CO2 gas input stream separated from a CH4 gas input stream by the conducting membrane. The CO2 is removed from the H2 and CO2 gas input stream as it contacts the membrane resulting in a H2 gas output stream from the H2 and CO2 gas input stream and a CO and H2 gas output stream from the CH4 gas input stream.

Abstract: The present disclosed embodiments relate to systems and methods for dehumidifying air by establishing a humidity gradient across a water selective permeable membrane in a dehumidification unit. Water vapor from relatively humid atmospheric air entering the dehumidification unit is extracted by the dehumidification unit without substantial membrane water vapor rejection into a low pressure water vapor chamber operating at a partial pressure of water vapor lower than the partial pressure of water vapor in the relatively humid atmospheric air. For example, water vapor is extracted through a water permeable membrane of the dehumidification unit into the low pressure water vapor chamber. As such, the air exiting the dehumidification unit is less humid than the air entering the dehumidification unit. The low pressure water vapor extracted from the air is subsequently expelled through a membrane vapor rejection unit to ambient conditions.

Abstract: A water vapor permeable membrane is provided comprising a dense layer and a support layer that are adjacent to each other, wherein the dense layer contains voids with a void length of 0.1 ?m or less and the dense layer has a thickness of 0.1 ?m or more and 2 ?m or less while in the support layer, void (a), i.e. the void with the largest length in the 2 ?m thick region measured from the boundary between the dense layer and the support layer into the support layer, has a length of 0.3 ?m or more and void (b), i.e. the void with the largest length in the region ranging between 2 ?m and 4 ?m measured from the boundary into the support layer, has a length of 0.5 ?m or more, the length of the void (b) being larger than that of the void (a). A water vapor permeable membrane having both a high water vapor permeability and a low air leakage is provided.

Abstract: The present disclosure relates to systems and methods for dehumidifying air by establishing a humidity gradient across a water selective permeable membrane in a dehumidification unit. Water vapor from relatively humid atmospheric air entering the dehumidification unit is extracted by the dehumidification unit without substantial condensation into a low pressure water vapor chamber operating at a partial pressure of water vapor lower than the partial pressure of water vapor in the relatively humid atmospheric air. For example, water vapor is extracted through a water permeable membrane of the dehumidification unit into the low pressure water vapor chamber. As such, the air exiting the dehumidification unit is less humid than the air entering the dehumidification unit. The low pressure water vapor extracted from the air is subsequently condensed and removed from the system at ambient conditions.

Abstract: A membrane cartridge is manufactured by repeatedly folding and joining two strips of membrane to form a cross-pleated cartridge with a stack of openings or fluid passageways configured in an alternating cross-flow arrangement. The cartridge can be modified for other flow configurations including co-flow and counter-flow arrangements. Methods for manufacturing such cross-pleated membrane cartridges, as well as apparatus used in the manufacturing process are described. Cross-pleated membrane cartridges comprising water-permeable membranes can be used in a variety of applications, including in heat and water vapor exchangers. In particular they can be incorporated into energy recovery ventilators (ERVs) for exchanging heat and water vapor between air streams being directed into and out of buildings.

Abstract: Process for separating propane and propylene using a distillation column and at least one membrane separation unit constituted by one or more modules operating in series, said membrane separation unit being placed either upstream, or downstream, or upstream and downstream of the distillation column.

Abstract: A gas separation unit 102, 200, 300 for permeating a gas out from a pressurized feed mixture includes an input manifold 104, 204, an exhaust manifold, 106, 206 and a permeate assembly 108, 208, 303. The permeate assembly supports one or more permselective foils 130, 132, 218, 232, 318 over a hollow cavity 134, 272, 306 supported by a microscreen element 142, 144, 228, 230, 326. The microscreen element includes non-porous perimeter walls 190, 192, 278 supported on a frame surface and a porous central area 194, 280 supported over the hollow cavity. A porous spacer 138, 140, 174, 234 disposed inside the hollow cavity structurally supports the entire microscreen surface spanning the hollow cavity while also providing a void volume for receiving fluid passing through the porous central area and for conveying the fluid through the hollow cavity.

Abstract: A membrane composition and process for its formation are disclosed from the removal of carbon dioxide (CO2) from mixed gases, such as flue gases of energy production facilities. The membrane includes a substrate layer comprising inorganic oxides, a barrier layer of in-situ formed Li2ZrO3, a Li2ZrO3 sorbent layer and an inorganic oxide cap layer. The membrane has a feed side for introduction of mixed gases containing nitrogen (N2) and a sweep side for recovery of CO2 wherein the membrane has a relatively high selectivity for CO2 transport at temperatures in the range of 400° to 700° C.

Abstract: The present invention provides a process for treating a natural gas stream comprising sending a natural gas stream to at least one membrane unit to produce a permeate stream containing a higher concentration of carbon dioxide and a retentate stream containing a lower concentration of carbon dioxide. Then the retentate stream is sent to an adsorbent bed to remove carbon dioxide and other impurities to produce a natural gas product stream. The regeneration gas stream is sent through the molecular sieve adsorbent bed to desorb the carbon dioxide. In one process flow scheme, the regeneration stream is combined with the permeate stream from the membrane unit. Then the combined stream is sent to an absorbent column to remove carbon dioxide from the permeate stream to produce a second natural gas product stream. In the alternative flow scheme, a second membrane unit is used to improve efficiency.

Abstract: A multi-stage membrane process for the removal of carbon dioxide from syngas streams containing at least about 5 volume percent carbon dioxide. The syngas is preferably obtained by the gasification of a biomass feedstock.

Abstract: A carbon dioxide permeable membrane is described. In some embodiments, the membrane includes a body having a first side and an opposite second side; a plurality of first regions formed from a molten carbonate having a temperature of about 400 degrees Celsius to about 1200 degrees Celsius, the plurality of first regions forming a portion of the body and the plurality of first regions extending from the first side of the body to the second side of the body; a plurality of second regions formed from an oxygen conductive solid oxide, the plurality of second regions combining with the plurality of first regions to form the body and the plurality of second regions extending from the first side of the body to the second side of the body; and the body is configured to allow carbon dioxide to pass from the first side to the second side.

Abstract: An apparatus and method for enhancing the heat and water recovery from a transport membrane condenser (TMC) includes a non-moving mechanical device inserted into the TMC tubes to increase the heat transfer efficiency via the enhancement of the fluid turbulence and/or surface area. The apparatus and methods may be applied to porous tubes arranged in a spaced array, similar to a conventional shell and tube heat exchanger device. Other configurations of the TMC may be conceived and adapted for use with the described apparatus and method.

Abstract: The invention concerns a process for the removal of gaseous acidic contaminants, especially carbon dioxide and/or hydrogen sulphide, in two or more stages from a gaseous hydrocarbonaceous feedstream (1) comprising hydrocarbons and said acidic contaminants, using one or more membranes in each separation stages. The gaseous hydrocarbonaceous feedstream is especially a natural gas stream. The process is especially suitable for feedstreams comprising very high amounts of acidic contaminants, especially carbon dioxide, e.g. more than 25 vol. %, or even more than 45 vol. %. In a first stage (2) a pure or almost pure stream of acidic contaminants is separated from the feedstream, the acidic contaminants (4) stream suitably containing less than 5 vol % of hydrocarbons. The remaining stream (3) comprises the hydrocarbons and still a certain amount of gaseous acidic contaminants.

Abstract: There is disclosed an asymmetric gas separation membrane exhibiting both improved gas separation performance and improved mechanical properties, which is made of a soluble aromatic polyimide comprised of a repeating unit represented by general formula (1): wherein B in general formula (1) B comprises 10 to 70 mol % of tetravalent unit B1 represented by general formula (B1) and 90 to 30 mol % of tetravalent unit B2 represented by general formula (B2), and A in general formula (1) comprises 10 to 50 mol % of bivalent unit A1 represented by general formula (A1a) or the like and 90 to 30 mol % of bivalent unit A2 represented by general formula (A2a) or the like.

Abstract: A proton conducting membrane comprising, as a main component, a ceramic structure in which an oxygen atom of a metal oxide is bonded through the oxygen atom with at least one group derived an oxygen acid selected from —B(O)3—, —S(?O)2(O)2—, —P(?O)(O)3—, —C(?O)(O)2—, and —N(O)3—, wherein the metal oxide and said at least one group derived from the oxygen acid share the oxygen atom, the proton conducting membrane being made by a sol-gel reaction of the oxygen acid or its precursor and a precursor of the metal oxide in order to obtain a sol-gel reaction product, followed by heating of the sol-gel reaction product at a temperature in a range of 100° C. to 600° C., the oxygen acid or its precursor being selected from a boric acid, a sulfuric acid, a phosphoric acid, a carbonic acid, a nitric acid, and precursors thereof. Thus, a novel proton conducting membrane is provided.

Abstract: A process for the production of a carbon hollow fiber membrane comprising: (i) dissolving at least one cellulose ester in a solvent to form a solution; (ii) dry/wet spinning the solution to form hollow fibers; (iii) deesterifying said hollow fibers with a base or an acid in the presence of an alcohol; (iv) if necessary, drying said fibers; (v) carbonizing the fibers; (vi) assembling the carbonized fibers to form a carbon hollow fiber membrane.

Abstract: A method of absorbing gases into a liquid comprising providing a stream of at least one desirable gas and at least one undesirable gas, exposing the gas stream to a liquid, so that the liquid absorbs more of the desirable gas than the undesirable gas, and releasing the liquid and gas mixture into an underground formation.

Abstract: The subject matter disclosed herein relates to gas separation membranes and, more specifically, to polyimide gas separation membranes. In an embodiment, a gas separation membrane includes a porous substrate, a substantially continuous polyimide membrane layer, and one or more layers of boehmite nanoparticles disposed between the porous substrate and the polyimide membrane layer to form a bond-coat layer. The bond-coat layer is configured to improve the adhesion of the polyimide membrane layer to the porous substrate, and the polyimide membrane layer has a thickness approximately 100 nm or less.

Abstract: The present invention relates to an apparatus to measure permeation of a gas through a membrane. The membrane is mounted on a flange with two sealing areas. The region between the sealing areas defines an annular space. The annular space is swept with a gas in order to carry away any of the permeating gas which may leak through the sealing areas.

Abstract: A hollow fiber element constituting a separation membrane module for separating an organic vapor is disclosed. At least one end part of a fiber bundle consisting of multiple hollow fiber membranes having a selective permeability is fixed and bound with a tube sheet formed by a cured material of an epoxy resin composition. Herein, a resin component of the epoxy resin composition contains an epoxy compound (A) represented by the following formula (1), an epoxy compound (B) represented by the following formula (2) and an aromatic amine compound (C), and wherein the epoxy compound (A) and the epoxy compound (B) are blended at a proportion in a range from 90:10 to 60:40 by weight; wherein R denotes alkyl group having 1 to 3 carbon atoms or hydrogen atom.

Abstract: A fuel source for an electrochemical cell includes two or more chemical hydride pellets, a flexible, porous, liquid water impermeable, hydrogen and water vapor permeable membrane in contact with and at least partially surrounding each hydride pellet, and a porous metal hydride layer positioned between each hydride pellet. Air gaps are between each pellet.

Abstract: A membrane selectively permeable to light gases comprises a membrane body formed by a first plate and a second plate. The second plate comprises a thin layer that is selectively gas-permeable. In the region of windows, this layer is exposed. There, support is provided by a porous bottom wall in the first plate or by narrow bores in the second plate. A heating device causes a radiation heating of the windows.

Abstract: A process for the recovery of carbon dioxide from a gas mixture that includes pretreating a gas mixture comprising carbon dioxide, water vapor, and one or more light gases in a pretreating system to form a cooled gas mixture, fractionating the cooled gas mixture to recover a bottoms fraction comprising carbon dioxide and an overheads fraction comprising carbon dioxide and the light gases, passing the overheads fraction over a membrane selective to carbon dioxide to separate a carbon dioxide permeate from a residue gas comprising the light gases, recycling the carbon dioxide permeate to the pretreating system, and recovering at least a portion of the bottoms fraction as a purified carbon dioxide product stream is described.

Abstract: The invention relates to a device for drying a gas, in particular air, that comprises at least one chamber (5) with an inlet (5a) for the flow of gas to be treated and an outlet (5b) for the flow of treated gas, said chamber being limited by at least one membrane (6) having a water vapor perviousness that is significantly higher than the perviousness to other gases or vapors, a humidity absorbing material being provided or flowing against the membrane (6) on the side opposite the chamber. The device includes a stack of plates (P1, P2) provided with central openings (A, B); each chamber (5) is formed by a central opening (A) located between two parallel membranes (6) while the humidity absorbing material is provided against each membrane (6); each plate (P1) is sandwiched between two plates (P2, P3) including a housing (B, B1) for the humidity absorbing material; and a plurality of chambers (5) are stacked and connected in series.

Abstract: A thin film composite membrane comprises a core layer and a sheath UV-crosslinked polymer layer. The thin film composite membrane is produced by the co-extrusion of two polymer solutions. The core layer and the sheath layer can be separately optimized. The sheath layer may be UV-crosslinked to provide stability and selectivity at the desired operating temperature of the composite membrane.

Abstract: A hollow fiber carbon membrane is provided, which has excellent gas separation performance, unbreakable flexibility and high utility. The hollow fiber carbon membrane comprises carbonized substance obtained by calcination of a hollow fiber-like material formed from a polyphenylene oxide derivative, and has an external diameter in the range of 0.08 mm to 0.25 mm. The polyphenylene oxide derivative substantially comprises repeating units represented by the following (a) and (b) (in the structural formula, R11 and R12 independently represent hydrogen atom or sulfone group, except that R11 and R12 are both hydrogen atoms), wherein the ratio A (%) of the repeating unit (b) to the repeating units (a)+(b) satisfies 15%<A<60%.

Abstract: A filter media including a scrim, a polytetrafluoroethylene (PTFE) media substrate upon the scrim, and a layer of expanded polytetrafluoroethylene (ePTFE) membrane adhered to the PTFE media substrate on the scrim. The filter media is pleatable and has air permeability of approximately 3-10 cubic feet/min at a 0.5 inch H2O pressure drop and an original filtration efficiency greater than 99.0% when tested in an unused, unpleated condition with a 0.3 micron challenge aerosol at a flow rate of 10.5 feet/min and when tested after a cleanable dust performance test according to ASTM D6830.

Abstract: A porous carbon membrane has as a loaded component water, alcohol, ether, or ketone loaded on a surface or in a pore, or on the surface and in the pore thereof. The carbon membrane has the loaded component preferably having a molecular weight of 100 or less. The carbon membrane has the loaded component preferably being linear alcohol or linear ether. The carbon membrane has the loaded component preferably being at least one selected from methanol, ethanol, n-propanol, and n-butanol. There is provided a carbon membrane having high separation performance and little change in the separation performance with the passage of time.

Abstract: A gas separation process for treating flue gases from combustion processes, and combustion processes including such gas separation. The invention involves routing a first portion of the flue gas stream to be treated to an absorption-based carbon dioxide capture step, while simultaneously flowing a second portion of the flue gas across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, then passing the permeate/sweep gas to the combustor.

Abstract: A method of making a crosslinked polyimide membrane is described. A monoesterified membrane is formed from a monoesterified polyimide polymer. The monoesterified membrane is subjected to transesterification conditions to form a crosslinked membrane. The monoesterified membrane is incorporated with an organic titanate catalyst before or after formation of the monoesterified membrane. A crosslinked polyimide membrane made using the aforementioned method and a method of using the membrane to separate fluids in a fluid mixture also are described.

Abstract: A water trap (1) improved with respect to handling and operational safety includes: two semipermeable membranes (2) and at least one tank (7), wherein the membranes have a water penetration pressure greater than 750 hPa and are made of the same or different PTFE laminates. The gas flow is divided in a ratio between 10:90 and 25:75 into the flush-/purge branch and analysis branch to the sensors (12) and a path parallel to the sensors (12), respectively, with the aid of the membranes and downstream filter elements and via the material and configuration.

Abstract: A method for producing membranes which contain at least one solid layer on one side of a porous substrate by treating the side of the support, which is to be coated, with a synthetic solution that forms the solid layer. The inventive method is characterized in that the space located behind the side of the porous support, which is not to be coated, is filled with an inert fluid during the production of the solid layer on the porous support, “behind” being from the perspective of the support. The pressure and/or the temperature of the fluid is/are selected such that the synthetic solution is essentially prevented from entering in contact with the side of the porous support, which is not to be coated.

Abstract: Problem to be Solved: To provide a gas separation membrane having an excellent performance balance (balance between gas permeation performance and gas separation ability) as a gas separation membrane. Solution: A gas separation membrane comprising a porous support member and a gas separating resin layer formed on the porous support member, wherein the porous support member has a mode diameter as measured by a mercury porosimeter of from 0.005 ?m to 0.3 ?m, and a pore size distribution index as measured by the mercury porosimeter of from 1 to 15.

Abstract: The present invention relates to the selective separation of methane (“CH4”) from higher carbon number hydrocarbons (“HHC”s) in streams containing both methane and higher carbon number hydrocarbons (e.g. ethylene, ethane, propylene, propane, etc.) utilizing a zeolitic imidazolate framework (“ZIF”) material. Preferably, the stream to be separated is fed to the present process in a substantially gaseous phase. In preferred embodiments, the current invention is utilized in a process to separate methane from higher carbon number hydrocarbons in natural gas streams.

Abstract: A shared or common environment membrane reactor containing a plurality of planar membrane modules with top and bottom thin foil membranes supported by both an intermediary porous support plate and a central base which has both solid extended members and hollow regions or a hollow region whereby the two sides of the base are in fluid communication. The membrane reactor operates at elevate temperatures for generating hydrogen from hydrogen rich feed fuels.

Abstract: A fuel source for an electrochemical cell includes two or more chemical hydride pellets, a flexible, porous, liquid water impermeable, hydrogen and water vapor permeable membrane in contact with and at least partially surrounding each hydride pellet, and a porous metal hydride layer positioned between each hydride pellet. Air gaps are between each pellet.