The present disclosure relates to adsorbent assemblies for use in adsorption heating and/or cooling systems.
In the use of carbon adsorbents for adsorption heating and/or cooling systems, it is desirable to utilize carbon materials that exhibit high density, high thermal conductivity, and high gas permeability, as well as high volumetric capacity for the heat exchange fluid, e.g., a refrigerant gas such as ammonia (NH3), water (H2O) or nitrogen (N2).
U.S. Pat. No. 8,539,781 issued Sep. 24, 2013 describes adsorbent structures comprising adsorbent in contact with porous member(s) arranged to enable refrigerant gas to enter and exit the adsorbent, wherein heat conductive member(s) can be arranged in contact with the adsorbent to transfer heat between the adsorbent and a heat transfer fluid, in adsorbent-based heating and/or cooling systems.
It would be advantageous to provide new adsorbent structures that are adapted for adsorption heating and/or cooling, and that do not require the presence of a porous member in contact with the adsorbent.
Another issue in adsorption heating and/or cooling systems relates to the need to achieve efficient transfer of heat to and from the adsorbent in system operation. This requirement is adversely impacted by variability and dimensional tolerances of the adsorbent articles employed in the adsorption system, when such articles do not achieve the requisite level of contact with a heat exchange member to achieve good conductive heat transfer to and from the adsorbent. It would therefore be advantageous to provide adsorbent structures that resolve such deficiencies in heat transfer contact between adsorbent articles and metal housings or casings in which the adsorbent articles are disposed, and usefully accommodate variability in dimensions of the adsorbent articles as a result of their manufacture.
The present disclosure relates to adsorbent assemblies for use in adsorption heating and/or cooling systems.
In one aspect, the disclosure relates to an adsorbent assembly for use in an adsorption heating and/or cooling system, such adsorbent assembly comprising: an array of adsorbent articles in which at least one adsorbent article is arranged in at least one of the following compatible arrangements (i)-(iii):
Other aspects, features and embodiments of the disclosure will be more fully apparent from the ensuing description and appended claims.
The present disclosure relates to adsorbent assemblies for use in adsorption heating and/or cooling systems.
The adsorption heating and/or cooling systems with which the adsorbent assemblies of the present disclosure are employed, can be of any suitable type. The adsorption heating and/or cooling system may for example be embodied as a refrigeration system that includes a refrigerated container having an evaporator associated therewith, with the adsorbent assembly of the present disclosure arranged for adsorbing and desorbing a reversibly adsorbable gas such as ammonia (NH3), water/steam (H2O) or nitrogen (N2) or other suitable reversibly adsorbable fluid. The adsorption heating and/or cooling system in other applications may comprise solar collectors or other heat sources, such as supplies of waste heat, electrical heat sources, gas combustion heat sources such as natural gas or propane heating units, geothermal heat sources, or any other source or sources of heat useful in the adsorption-based heating and/or cooling system, and may additionally include sorption generators, condensers, and any other suitable apparatus and components, etc., as arranged with one or more adsorbent assemblies of the present disclosure, in an operational system to facilitate the heating and/or cooling cycle. The heating and/or cooling system may utilize a heat transfer fluid of any suitable type, and appropriate ancillary equipment, to facilitate heat exchange within the system.
As used herein, the term “adsorbable gas” refers to the reversibly adsorbable gas that is contacted with an adsorbent for adsorption thereon, and from which adsorbent the previously adsorbed gas is released during desorption, in the operation of the heating and/or cooling system in which the adsorbent assembly of the present disclosure is employed. The term “gas” in such context is intended to be broadly construed, to encompass any suitable fluids.
The term “heat transfer fluid” as used herein refers to fluid that is used to translate the heating or cooling that results from the adsorption or desorption of an adsorbable gas, to the rest of the heating and/or cooling system in which the adsorbent assembly is employed. For example, such fluid may comprise a water or glycol solution, or other fluid medium of appropriate type for the specific system in which the adsorbent assembly is employed.
As used herein, the term “tube” refers to an elongate passage member enclosing an interior volume. In various embodiments of the disclosure, as hereinafter more fully described, tubes may be provided with matable engagement surfaces, such as flat surfaces, enabling a plurality of such tubes to be close-packed or nested with one another in an array in which respective tubes are directionally aligned with one another. Accordingly, apart from any matable engagement surfaces, e.g., flat surface portions of the tube representing planar portions of the cross-sectional shape, the tubes may have any suitable shape, size and conformation enabling adsorbent when disposed therein to adsorb and desorb reversibly adsorbable gas in an adsorption heating and/or cooling system. For example, the tube may have a cross-section that is triangular, sector-shaped, square, rectangular, pentagonal, hexagonal, octagonal or otherwise polygonal, or it may include an arcuate circumference with a chordal flat surface, such as an otherwise circular cross-section with a chordal flat surface, to facilitate close-packing and/or conductive heat transfer relationship between adjacent tubes in an aligned array. Further, such shapes may be geometrically regular or irregular, and if geometrically regular may include truncated portions of such shapes, wherein the truncation edge is a flat surface or of other surface conformation. A variety of tube cross-sectional shapes is illustratively described hereinafter, in connection with various tube-in tube embodiments of the adsorbent assemblies.
As used herein, the term “piece density” refers to the density of an adsorbent article (“piece”), as determined by measuring cross-sectional area of the article, multiplying such cross-sectional area by height of the article (cross-sectional area x height of the article) to yield a piece volume, and dividing the mass of the adsorbent article by the piece volume to yield the piece density for the adsorbent article.
The disclosure in one aspect relates to an adsorbent assembly for use in an adsorption heating and/or cooling system, such adsorbent assembly comprising: an array of adsorbent articles in which at least one adsorbent article is arranged in at least one of the following compatible arrangements (i)-(iii):
The adsorbent articles may comprise any suitable adsorbent, e.g., carbon adsorbent, activated carbon adsorbent, or other adsorbent medium, such as silica, alumina, aluminosilicate or other zeolite adsorbents, adsorbent clays, macroreticulate polymer adsorbents, metalorganic frameworks (MOFs), etc. When carbon adsorbent is used as the adsorbent in the adsorbent assembly, the carbon adsorbent in specific embodiments may comprise a carbon pyrolyzate of a resin selected from the group consisting of polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), PVDC-polymethylacrylate (PVDC-PMA), PVDF-polymethylacrylate (PVDF-PMA), polyvinylidene chloride-polyvinyl chloride (PVDC-PVC) copolymers, polyvinylidene fluoride-polyvinyl chloride (PVDF-PVC) copolymers, polyfurfuryl alcohol (PFA), polystyrene, phenolics, sugars, lignin, cellulosics, and other carbon precursors that are susceptible to being formed to a desired shape or conformation and processed by pyrolysis to provide suitable adsorbent.
In various embodiments, the carbon adsorbent may have one or more of the following properties:
In other embodiments, the carbon adsorbent may have the following properties: (a) a fill density measured for ammonia at 25° C. and pressure of 650 torr that is greater than 180 grams per liter of adsorbent and (b) a bulk density of from about 0.60 to about 2.0 grams per cubic centimeter.
In various embodiments, the adsorbent assembly may comprise adsorbent having sorptive affinity for ammonia as the adsorbable gas employed in the adsorption heating and/or cooling system in which the adsorbent assembly is used. Adsorbent suitable for reversible adsorption of other adsorption heating and/or cooling fluids may be utilized, and a wide variety of such fluids may be employed, in the general practice of the present disclosure.
In some embodiments, the array of adsorbent articles may comprise a stack of adsorbent disk-shaped pucks, each of which may have one or more openings therethrough and wherein corresponding openings of the pucks in the stack are aligned with one another to form a communicating gas flow passage. The openings may be located anywhere on the adsorbent articles, and may for example be central openings, peripheral region openings, or openings in an intermediate area between the central region and edge of the adsorbent articles.
In various embodiments, outer edge surface of the pucks in the stack may be in contact with a heat transfer member, e.g., an inner surface of a housing in which the adsorbent assembly is used.
In other embodiments, the array of adsorbent articles may comprise a stack of adsorbent disk-shaped pucks, each of which may have a peripheral notch. In such arrangement, the peripheral notches of adsorbent disk-shaped pucks in the stack may be aligned with one another to form a communicating gas flow passage. Alternatively, the peripheral notches of successive adsorbent disk-shaped pucks in the stack may be circumferentially offset in relation to each other. In still other embodiments, some successive adsorbent disk-shaped pucks in the stack are circumferentially offset in relation to each other, and others of the successive adsorbent disk-shaped pucks in the stack are aligned with one another.
In various embodiments, at least some of the adsorbent articles may be disk-shaped, and comprise half-sections abuttingly mated with one another along diametral surfaces thereof
The adsorbent assemblies of the disclosure in still other embodiments may be configured with at least one adsorbent article comprising a beveled edge surface.
In other implementations, at least one adsorbent article in the adsorbent assembly comprises a peripheral notch.
In still other implementations, at least one adsorbent article that has a conformation selected from the group consisting of triangular conformations, circular sector conformations, disk conformations, square conformations, rectangular conformations, hexagonal conformations, octagonal conformations, and dodecagonal conformations. Such adsorbent article(s) may have an opening therethrough, and/or may comprise a peripheral notch, and/or may comprise a truncated corner, and/or may comprise a beveled edge surface.
The adsorbent assemblies of the present disclosure may be utilized in adsorption heating and/or cooling systems of widely varying type, and such heating and/or cooling systems may include a corresponding variety of components, e.g., solar collectors, gas-fired heaters, hot-water boilers, waste heat sources and other sources of heat transfer fluid.
In various embodiments, the adsorbent assembly may be configured with at least one adsorbent article being in a tube comprising at least one matable engagement surface, e.g., a flat surface, which is in contact with a complementary matable engagement surface, e.g., a flat surface of another tube containing at least one adsorbent article. The respective matable engagement surfaces of the respective tubes are appropriately configured to contact one another. Such matable engagement surfaces may be of any suitable type, and may be planar or flat surfaces, arcuate services, serpentine or cog-shaped surfaces, or of any other suitable conformation that enables contacting engagement of surface areas of the respective tubes with one another.
In various embodiments, each tube may have a circular sector cross-sectional shape, comprising an arcuate outer wall and radially inwardly convergent sidewalls. Each of the tubes may be of elongate form, and may have a same length, or different lengths. Each tube may be arranged to be in contact at each of its sidewalls with a sidewall of an adjacent tube, e.g., in which the tubes have a square cross-section and each planar side abuts a planar side of an adjacent tube of like character, to form a composite array of such tubes, or in which the tubes have an equilateral triangular cross-section, with each side surface of the tube abutting a side surface of an adjacent tube, to form a composite array of tubes. The tubes may be arranged so that they form a cylindrical assembly comprising the tubes, such as in an array comprising pie-shaped sectors circumferentially arranged with each sector's arcuate outer wall being circumferentially aligned with the other sector outer walls in the cylindrical assembly, so that the arcuate outer walls of all sector-cross-sectioned tubes in the cylindrical assembly form an outer wall surface of the assembly, and with all inner apices of the sector-cross-sectioned tubes being at the central axis of the assembly.
In various embodiments, the outermost wall surfaces of matably engaged tubes in an adsorbent assembly may be in contact with a heat transfer member, such as the interior surface of a housing in which the adsorbent assembly is disposed, or alternatively, the outermost wall surfaces of matably engaged tubes in the adsorbent assembly may be in spaced relation to a heat transfer member, e.g., the interior surface of a housing in which the adsorbent assembly is disposed, to form a fluid passage therebetween adapted for flow of a heat transfer fluid therethrough.
In another embodiment, at least one adsorbent article of the adsorbent assembly is in contact with a deformable foil member that is in contact with at least one other adsorbent article and/or a heat transfer member, e.g., an interior surface of a housing in which the adsorbent assembly is disposed. For example, the deformable foil member may be in contact with at least one other adsorbent article, or in contact with a heat transfer member such as the interior surface of the housing, or in contact with at least one other adsorbent article and in contact with a heat transfer member such as the interior surface of the housing.
The deformable foil member may have a receptacle conformation, e.g., in which the deformable foil member in the receptacle conformation comprises a sidewall flaring outwardly and upwardly from a periphery of a floor portion of the deformable foil member. The sidewall may be corrugated, crimped, accordion-folded, or otherwise be expanded or expandable in character, so as to be compactible or compressible to fill a space between adjacent adsorbent articles and/or a space between an adsorbent article and a heat transfer member associated there with, such as the interior wall of a housing that contains the adsorbent articles in its interior volume.
In various embodiments, the floor of the deformable foil receptacle may have a central opening in the floor thereof
The adsorbent assembly may therefore be arranged, so that the deformable foil receptacle is disposed with its sidewall, at an upper portion thereof, being in contact with a heat transfer member, e.g., the interior surface of a housing in which the adsorbent assembly is disposed, to accommodate conductive heat transfer between the heat transfer member and the adsorbent. In other arrangements, the array of adsorbent articles may comprise a stack of adsorbent articles, in which at least some of the articles in the stack are reposed on a deformable foil member of the above-described type.
The deformable foil member may be formed of any suitable material of construction. For example, the foil may comprise a material selected from group consisting of metals, metal alloys, thermally conductive polymers, graphite fibers, graphene, flexible graphite, and carbon nanotube felt. In some embodiments, the deformable foil member comprises a metal or metal alloy foil. The deformable foil member may comprise foil having any suitable thickness, e.g., a thickness in a range of from 0.005 mm to 0.5 mm, or in other ranges including greater or lesser thicknesses. The deformable foil member may be constructed with foil that is corrugated, crimped, or accordion folded, or otherwise constituted so as to be compactible or compressible to establish thermally conductive contact between the adsorbent article and at least one other adsorbent article and/or a heat transfer member, e.g., the interior surface of the housing.
The adsorbent assembly of the present disclosure may be employed with an adsorbable/desorbable fluid of any suitable type, such as ammonia, water, nitrogen, or other reversibly adsorbable gas.
In use, the adsorbent assembly may be arranged in an adsorption heating and/or cooling system of appropriate type, e.g., a system comprising a solar collector, gas combustion heater, electrical resistance heater, waste heat source, or other heat supply apparatus that is adapted for heating a heat transfer fluid, with the heat transfer fluid being arranged to exchange heat with the adsorbent, e.g., by heat exchange with a housing and/or tubes containing the adsorbent. The heat transfer fluid may be of any suitable type that is usefully employed in the specific system, and may for example comprise an aqueous medium or solution, a glycol composition, hydrocarbon fluid, brines, silicone oils, or the like.
The adsorbent assembly of the present disclosure may utilize adsorbent articles comprising any suitable adsorbent having sorptive affinity for an adsorbable gas in the use of the assembly. The adsorbent articles may for example comprise molecular sieves, macroreticulate resins, silica, alumina, carbon adsorbent, etc.
In various specific embodiments, ammonia may be employed as a reversibly adsorbable gas in operation of corresponding adsorbent assemblies, e.g., assemblies comprising carbon adsorbent or other suitable adsorbent material.
In some embodiments, the adsorbent assemblies comprise adsorbent that is contained in a tight fitting metal tube in order to facilitate rapid transfer of heat radially into and out of the adsorbent while a reversibly adsorbable gas cyclically flows axially in and out of the tube, and wherein the adsorbent is configured to enable rapid gas transfer into and out of the tube. As used in such context, the term “tight fitting” means that the adsorbent members are in direct contact with interior surface of the metal tube or in direct contact with a deformable metal foil member that is in turn in contact with the inside of the tube.
The adsorbent for such purpose may be configured with one or more gas flow openings or channels in the articles to facilitate adsorbable gas movement through the stack of adsorbent articles in the metal tube, as shown in
The housing 10 is preferably a metal housing, but may be formed of other materials of construction having suitable thermal conductivity and heat capacity characteristics, such as glasses, ceramics, composite materials, and the like. When the housing is formed of metal, materials of construction such as aluminum, steel, brass, or the like, may be employed. The housing wall is in contact with a heat transfer fluid (such as water, propylene glycol, ethylene glycol, or other suitable heat transfer fluid), for heat transfer between the housing wall and the heat transfer fluid, as indicated in
The specific characteristics of the adsorbent articles 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32 employed in the adsorbent assembly will be determined at least in part by the specific adsorbable gas that is contacted with the adsorbent in the use of the adsorbent assembly in a heating and/or cooling system. In various embodiments, the reversibly adsorbable gas that is employed with the adsorbent assembly, as deployed in a heating and/or cooling system, comprises ammonia. Other reversibly adsorbable gases may alternatively be employed.
It will be recognized that the adsorbent may be appropriately selected in the broad practice of the present disclosure, for use with a specific adsorbable gas and a specific heat transfer fluid that are employed in a given application.
The adsorbent is appropriately selected to provide porosity of a pore size range and pore size distribution that will accommodate ready ingress and egress in the respective adsorption and desorption steps of the adsorption refrigeration process, or other adsorption/desorption heating and/or cooling mode of operation. The porosity may be tailored for such purpose, so that the average pore size is adapted to the molecular size and characteristics of the adsorbable gas employed in the system.
The adsorbent material employed in the adsorbent assemblies of the present disclosure can be manufactured utilizing resin starting materials that are formed into particular desired shapes and cured to form so-called green body articles, followed by pyrolysis at elevated temperatures, with subsequent optional activation, to yield product adsorbent articles for use in the adsorbent assemblies.
The manufacture of adsorbent articles in specific embodiments may comprise compressing or otherwise compacting a green resin, e.g., polyvinylidene chloride (PVDC) or polyvinylidene fluoride (PVDF) or other starting material, into a desired conformation or form factor, followed by formation of gas flow passages in the resin structures, such as via mold forming or by drilling of one or more holes through the resin body, and pyrolysis of the resin or other pyrolyzabable starting material, to yield a carbon monolith adsorbent article of desired dimensions and conformation.
Depending on the exact requirements of the adsorption system application, mixing steps may also be employed to add materials to improve the thermal conductivity and/or permeability of the adsorbent product. The drilling of any required holes in the polymer workpiece for adsorbable gas flow may be carried out in any suitable manner, such as drilling, laser ablation, electrical discharge machining, or the like. Such techniques may be manual or automated in character.
Alternatively, or additionally, the adsorbent articles may be formed with one or more peripheral involutions or cut-outs (notches) to accommodate the flow of the reversibly adsorbable gas through a stack or other array of the adsorbent articles, in which such involutions or cut-outs serve to define gas flow passages in the adsorbent. By utilizing a formable starting material for the adsorbent, the adsorbent article can be formed in a raw starting material (e.g., polymer) piece (green body) without additional machining or fabrication steps that would otherwise be involved if an adsorbent body required post-casting mechanical operations to form gas flow passage structure therein.
An illustrative adsorbent article 40 is shown in
A series of such disk or tablet adsorbent articles of notched character may be stacked in a tube, in which each adsorbent article is aligned with a previous one in the stack, to form an axially continuous passage at the outer edge of the stack constituted by the successive notches that are aligned with one another, allowing rapid gas transfer throughout the entire stack of adsorbent articles. Such peripheral notch structure sacrifices minimal surface area, while maintaining extensive remaining edge surface around the circumference of the disk or tablet article that is effective to provide heat transfer area between the edge of the adsorbent article and the inner surface of the circumscribing metal housing in which the stack of notched disk or tablet adsorbent articles is disposed.
In other embodiments, the individual adsorbent articles may be formed from partial sections that are assembled to form the final article, as e.g., with the partial sections arranged in abutment to one another to form gas flow passages in the assembled adsorbent article. For example,
Another embodiment of a disk- or tablet-shaped adsorbent article 60 is shown in
Additional forms of adsorbent articles that may be usefully employed in specific applications of the disclosure are shown in
It will be appreciated from the foregoing description that the specific conformation of the adsorbent articles may be widely varied in the practice of the present disclosure, and that such adsorbent articles may have a shape and thickness adapted to achieve substantial contact with a casing or housing in which the adsorbent articles are disposed, for the purpose of achieving optimal thermal exchange with the casing or housing as a heat transfer member. Similarly, bevels, grooves, bores, and notches can be configured in various manners, angles, and numbers to accommodate improved flow of gas though the adsorbent bed, as can the number and size of the adsorbent pieces employed to form such adsorbent beds.
In various embodiments, the stacked or otherwise assembled adsorbent articles can be arranged with conductive metal elements between adjacent adsorbent articles, to thereby enhance heat transfer between the adsorbent articles and/or between the adsorbent articles and a casing or housing of an adsorption heating and/or cooling assembly. For example, metal plates or other heat transfer members can be provided between successive adsorbent articles in an elongate, e.g., vertically upstanding, stack of such articles. Such metal plates may have a diameter that is substantially equal to the inner diameter of the casing or housing, so that the plates are press-fitted to provide good thermal contact for conductive heat transfer between the enclosing wall and the adsorbent articles disposed in the interior volume of the enclosure.
The preceding description has been directed to adsorbent assemblies for use in adsorption heating and/or cooling systems in which adsorbent articles are disposed in a tube, in thermal contact with the tube. According to another aspect of the disclosure, a multiplicity of tubes may be provided in an enclosure, each containing adsorbent, e.g., in a stack of adsorbent articles as previously described, but wherein the heating and/or cooling assembly comprises a tube-in-a-tube arrangement. In such tube-in-a-tube arrangements, each constituent tube in the interior volume of the enclosure provides extended heat transfer area for distributing heat flow within the enclosure containing the multiple adsorbent-containing tubes. The adsorbent-containing tubes may be of any suitable cross-sectional geometry, e.g., triangular, square, rectangular, hexagonal, circular, or other geometrically regular or irregular shapes that preferably are adapted to abuttingly mate with or inter-fit with one another.
The adsorbent assemblies of the present disclosure may be utilized in a tube-in-a-tube heating and/or cooling system of a type as shown in
Although the preceding discussion has been directed to elongate stacks of successively abutting adsorbent articles, it will be appreciated that the adsorbent in the interior tubes in the tube-in-a-tube heating and/or cooling system may be formed in situ to yield a continuous adsorbent medium in the tube. This may for example be achieved by filling the interior volume of the constituent interior tubes with a precursor resin for the carbon pyrolyzate material that is employed as the adsorbent medium, with the resin thereafter being cured and subsequently pyrolyzed in the interior tube to yield the continuous adsorbent medium therein.
In various embodiments, the adsorbent arrangement in the adsorbent assemblies includes pie-shaped sector segments, as variously shown in
Alternatively, the outer curvate wall of the inner tubes 224 may be disposed in direct contact with interior surface of the enclosure 222, and with axial, e.g., central, passage(s) for flow of heat transfer fluid in contact with the inner tube assembly in the enclosure 222. In still other arrangements, heat transfer fluid flow passages may be provided at the inner wall surface of the enclosure, as well as elsewhere for heat transfer with the inner tubes. It will be recognized that numerous alternative flow passage arrangements may be provided, in specific configurations of a heating and/or cooling system in which the adsorbent assembly of the present disclosure is used.
In the use oftuhu-in-k/hu adsorbent arrangements of the type disclosed above, the inner tubes can be circular, triangular, square, or hexagonal in cross-section, or may have any other shape and configuration. The outer tube or housing may be of any shape to maximize packing density of the inner tubes in the heating/cooling system. The inner tubes may have any convenient wall thickness, and may be manufactured by an appropriate method, such as drawing, extruding, roll-forming, welding, etc. and may be of any suitable material, e.g., aluminum, copper, steel/stainless steel/galvanized steel, etc.
In the use of adsorbent assemblies of the present disclosure, high thermal conductivity materials and thin walls of the interior tubes will enhance heat transfer and system performance, and close spacing of interior thin-walled tubes will minimize thermal mass, important for improving efficiency and for cycling of the heating/cooling system. This approach will result in a lower number of welded connections, thereby simplifying manufacturing of the adsorbent assemblies and lowering costs with improved reliability and less chance of leaks in the system. The close-packed array of inner tubes may utilize tubes of different geometric cross-sectional shape, as useful to increase the density of the inner tubes in the interior volume of the housing. The enclosure itself may be of any suitable shape and size, e.g., to allow an adsorption compressor to be placed inside the housing. Since thin-walled inner tubes will be contained within a non-compressible heat transfer fluid, and since the external housing tube can be made thicker, gas pressure within the inner tubes may be appropriately selected to avoid deformation or fracture of the adsorption (inner) tubes. This in turn minimizes the overall size of the compressor and thus may significantly lower the weight of the heating/cooling system.
In a specific embodiment, the inner tubes of a tube-in-tube adsorbent assembly may contain nanoporous carbon articles to adsorb ammonia or other adsorbable gas, in which the nanoporous carbon articles are formed so as to fill the inner tubes. The adsorbent may be formed, for example, by pressing polyvinylidene chloride (PVDC) or polyvinylidene chloride-polymethylacrylate (PVDC-PMA) copolymers into desired bodies and then firing such bodies at high temperature, with additional post-processing, if desired, e.g., as disclosed in US. Pat. No. 6,743,278. Truncations, notches, holes and/or edge bevels may be applied during the pressing process to allow for increased gas flow and to ensure proper alignment inside the tubes. The adsorbent articles may as described comprise truncations, holes, notches, etc., to increase gas flow within the inner tube, and the respective articles may or may not be aligned, as may be appropriate to provide a desired adsorbable gas flow path through the adsorbent material. If each inner tube has at least one flat side, correspondingly formed adsorbent articles will “self-align” inside the inner tubes and remain aligned without undue movement in relation to each other, thereby minimizing abrasion and attrition loss of the adsorbent as a result of transport or movement of the heating and/or cooling system, exposure to vibration during operation, or other perturbations that may cause rubbing and consequent attrition of adsorbent articles in contact with one another.
In embodiments in which the adsorbent comprises a carbon adsorbent that is formed as a pyrolysis product of a starting material, e.g. a resin, the curing, pyrolysis and optional activation steps may result in shrinkage of the pre-formed material, or in other dimensional alteration. Such dimensional alteration may in turn affect the utility of adsorbent assemblies comprising adsorbent articles in a housing in which the adsorbent is desired to be in thermal contact with interior surface of the housing. For example, shrinkage or differential dimensional changes caused by thermal inhomogeneities in the pyrolysis or other processing operations may result in the assembled adsorbent articles failing to achieve direct complete abutting contact with a housing interior wall surface, or complete abutting contact with walls of the inner tubes, in a tube-within-a-tube arrangement of the adsorbent assembly.
Such mismatch, between the adsorbent article dimensions and the interior volume dimensions of a housing, or between the adsorbent article dimensions and the dimensions of inner tubes in a housing, could result in significant diminution of the heat transfer between the housing wall and the adsorbent articles in the adsorbent assembly, or between the inner tubes and the adsorbent articles in such inner tubes of the adsorbent assembly.
As previously described, such dimensional mismatches and variations can be addressed by the provision of deformable foil members that can be disposed against the adsorbent article and provide extended surface for contacting the inner wall or other heat transfer member in proximity to the adsorbent article. As described hereinabove, the deformable foil member may be formed as a cup or receptacle having an outwardly flared portion, for contacting the inner wall or other heat transfer member, so that heat is conductively transmitted through the foil member to the adsorbent article, and vice versa. In such manner, the deformable foil member “bridges” the gap between the adsorbent article and the heat transfer member, such as the housing inner wall surface or the interior surface of an inner tube in a tube-within-a-tube arrangement.
The adsorbent article may be shaped or configured so that it mates with the deformable foil member, so that the deformable foil member provides conductive heat transfer capability for the adsorbent article engaged therewith. For example, the deformable foil member 230 is shown in
The deformable foil member approach resolves issues of dimensional tolerances of the adsorbent articles. For example, a PVDC-based carbon material shrinks considerably, e.g., by 25% or more during pyrolysis, and shrinks again during oxidative activation, with such shrinkage increasing the variability in geometry of the adsorbent pieces in relation to the “as pressed” green state of the adsorbent precursor articles. Thus, as mentioned, variance in diameter can result in some adsorbent articles being too small to make good thermal contact with tubing walls, and others may experience an excessively tight interference fit.
By utilizing a collapsible or compactible soft metal foil cup or other deformable thermally conductive foil member between successive adsorbent articles, thermal contact with a tube or enclosure wall is assured, to enable heat to translate radially in an effective manner. The deformable foil member in the form of foil cups can be prepared at very low cost and is effective to resolve the tolerance issues between the adsorbent article diameter and the tubing or enclosure cross-sectional dimensions. Aluminum foils are acceptable for use with heat transfer fluid such as ammonia. To facilitate adsorbable gas flow through the tubes, the metal foil cups can for example have center cut-outs as shown in
In the
The adsorbent assembly in the adsorption heating and/or cooling system 290 is arranged for heat input and heat output as schematically indicated by bidirectional arrows C and D, e.g., by provision of a heat exchange jacket or other heat transfer fluid arrangement providing heat transfer relationship to the exterior surface of the tube 292.
Although the use of deformable foil members to facilitate thermal contact of an adsorbent with a surrounding housing, tube, or casing has been described herein primarily in application to adsorption heating and/or cooling systems, it will be recognized that such usage may be employed in other applications in which a reversibly adsorbable gas is adsorbed on and subsequently desorbed from an adsorbent medium. For example, when the adsorbent is used as a gas storage and dispensing medium in a vessel containing adsorbent articles, the deformable foil members providing enhanced thermal contact between adsorbent articles and between adsorbent articles and the wall of the vessel may be usefully employed in thermally mediated adsorption and/or desorption of the gas, e.g., in a thermal swing adsorption (TSA) mode of operation, in which the adsorbent is heated to higher temperature to effect desorption of gas from the adsorbent, and cooled to lower temperature to effect loading of the adsorbent with the adsorbable gas.
Usage of the deformable foil members between adjacent adsorbent articles and in contact with a vessel wall may also be employed to thermally homogenize an adsorbent bed of such adsorbent articles so that they can be maintained in a substantially isothermal condition, without the occurrence of deleterious hotspots or cold spots in the adsorbent bed.
Accordingly, the usage of such deformable foil members in adsorbent assemblies in fluid storage and dispensing vessels containing adsorbent articles, even when heating is not used to effect desorption of gas from the adsorbent, is beneficial to isothermalize the vessel and to rapidly dissipate heat of adsorption during charging of adsorbable gas to the vessel for adsorption of such gas on the adsorbent articles therein.
While the disclosure has been set forth herein in reference to specific aspects, features and illustrative embodiments, it will be appreciated that the utility of the disclosure is not thus limited, but rather extends to and encompasses numerous other variations, modifications and alternative embodiments, as will suggest themselves to those of ordinary skill in the field of the present disclosure, based on the description herein. Correspondingly, the disclosure as hereinafter claimed is intended to be broadly construed and interpreted, as including all such variations, modifications and alternative embodiments, within its spirit and scope.
Filing Document | Filing Date | Country | Kind |
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PCT/US14/67808 | 11/28/2014 | WO | 00 |
Number | Date | Country | |
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61910072 | Nov 2013 | US |