Structure with an external support for a particle adsorption bed for a suction gas separation process

Abstract

A gas separation unit for separating carbon dioxide from air has been proposed for use in a circulating adsorption / desorption process using a loose granular sorbent material. The loose granular sorbent material is disposed within the internal volume of an external support structure and supported by the external support structure, which includes a plurality of base portions, deflecting portions, and openings. The sheets are arranged in parallel to define an inlet face and an outlet face and are disposed at a distance in the range of 0.1 to 2.5 cm (preferably 0.1 to 0.5 cm). The inflowing stream passes through the inlet face and then through the granular sorbent material disposed within the cavities of each layer, and then exits the layer through the outlet face to form a gas outflow stream. The directionality of the inflowing and outflowing streams through the external support structure is controlled by the deflecting portions of the external support structure.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 357,925, filed on July 1, 2022, and incorporates by reference the same in its entirety for all purposes.

[0002] Field The present disclosure relates to an adsorption bed structure for gas separation processes and the use of such a structure for gas separation, such as the separation / recapture of CO2 from a gas stream.

Background Art

[0003] Background Gas separation by adsorption has various applications in industry, such as removing specific components from a gas stream, where the desired product can be either the removed component, the remaining depleted stream, or both. Thereby, both trace and major components of a gas stream can be targeted by the adsorption process.

[0004] One important application is to recover carbon dioxide (CO2) from a gas stream, such as flue gas, exhaust gas, industrial waste gas, or the atmosphere.

[0005] A method called direct air capture (DAC) that directly captures CO2 from the atmosphere is one of several means to reduce anthropogenic greenhouse gas emissions and has an attractive economic outlook as a non-fossil and location-independent CO2 source for the commodity market and the production of synthetic fuels. Specific advantages of CO2 capture from the atmosphere include: (i) DAC can address emissions from distributed sources (such as cars and airplanes) that account for most of the world's greenhouse gas emissions and cannot currently be captured at the emission site in an economically feasible way; (ii) since DAC can address past emissions, it can truly produce negative emissions; (iii) DAC systems do not need to be attached to emission sources and are rather location-independent and can be installed, for example, at the site of CO2 treatment; (iv) when the CO2 captured from the atmosphere is used in the production of synthetic hydrocarbon fuels from renewable energy sources, it is possible to obtain a truly non-fossil fuel for the transportation sector that produces little or no pure CO2 emissions to the atmosphere.

[0006] Recently, several DAC methods based on various technical approaches have been developed. For example, U.S. Patent No. 8,163,066 (B2) (Eisenberger) discloses the structure and technology of carbon dioxide capture / regeneration. U.S. Patent Application Publication No. 2009 / 0120288 (A1) (Lackner et al.) discloses a method for removing carbon dioxide from air. U.S. Patent Application Publication No. 2012 / 0174778 (A1) (Eisenberger) discloses a carbon dioxide capture / regeneration method using a vertical elevator. Also, WO2010022339A2 (Alberta Ltd.) discloses a method and equipment for carbon dioxide capture.

[0007] One particular approach is based on a cyclic adsorption / desorption process for a chemically functionalized solid sorbent material. For example, in WO2010 / 091831 (Eth Zurich), a structure based on an amine-functionalized solid sorbent material and a cyclic adsorption / desorption process for extracting carbon dioxide from ambient air using this material are disclosed.

[0008] Therein, the adsorption process is carried out under ambient conditions, air flows through the sorptive material, and a portion of the CO2 contained in the air chemically binds to the amine-functionalized surface of the sorbent. During subsequent desorption, the material is heated to about 50 - 110 °C, and the partial pressure of carbon dioxide surrounding the sorbent is reduced by applying a vacuum or exposing the sorbent to a purge gas stream. Thereby, the previously recovered carbon dioxide is removed from the sorptive material and obtained in a concentrated form.

[0009] WO2012 / 168346A1 (Empa Eidgenossische Materialprufungs - Und Forschungsanstalt) discloses a sorptive material based on amine-functionalized cellulose, which can be used in the above process.

[0010] Generally, in gas separation processes based on adsorption, a configuration of the sorptive material is desired that gives little pressure drop to the gas stream, minimizes the energy required for gas pumps, and at the same time maximizes the contact between the sorbent and the gas stream to maximize the mass transfer rate of the components removed from the gas stream. Typical configurations include packed bed columns or fluidized beds typically tens of centimeters to several meters in length, which typically give a pressure drop to the gas stream of several thousand pascals to several bar.

[0011] When trace components are removed from a gas stream, the requirements for pressure drop can be even more stringent. In particular, all DAC approaches have a common major challenge in that a very large volume of air must be passed through the recovery system to extract a specific amount of CO2 from the air. This is because the CO2 concentration in the atmosphere is very low, currently 390 - 400 ppm, i.e., approximately 0.04%. Thus, to extract one metric ton of CO2 from the atmosphere, at least about 1,400,000 cubic meters of air must be passed through the recovery system. This means that in an economically viable recovery system, the pressure drop of the passing air stream must be very low. Otherwise, the system will become uneconomical due to the energy requirements of the air pump. However, even with a low-pressure-drop configuration, the mass transfer characteristics of the system should not be impaired.

[0012] Many materials with promising properties for the DAC process are typically granular, but placing them in conventional packed-bed columns or fluidized beds that are typically tens of centimeters to several meters in length usually is not feasible because the resulting pressure drop exceeds the tolerance limit by one or several orders of magnitude.

[0013] On the other hand, in the field of particulate filters for gas streams, particularly in the specific field of soot particulate filters for exhaust gases, channeled filter structures have been developed and are typically referred to as "wall flow" filters. See, for example, EP 0 766 993 A2 (Toyota Jidosha Kabushiki Kaisha). In these structures, the gas stream enters the structure from the inlet channels, passes through the porous walls where soot particles are collected, and exits the structure through the outlet channels.

[0014] Monolithic structures containing sorbent materials have also been developed in relation to gas separation and adsorption, such as WO2010 / 027929A1 (Alstom Technology Ltd), U.S. Patent No. 8,202,350 (B2) (SRI International). SUMMARY OF THE INVENTION

[0015] Abstract U.S. Patent No. 9,751,039 (B2) (hereinafter, the “’039 Climeworks publication”) assigned to Climeworks AG and U.S. Patent No. 10,427,086 (hereinafter, the “’086 Climeworks publication”) assigned to Climeworks AG relate to the structure of a granular sorbent bed for gas separation by adsorption, which structure can achieve both advantages of very low pressure drop of a gas flow passing through the structure and very high mass transfer rate between the gas phase and the surface of the sorbent material. The basic principle of the structure of these publications is that the particles of the sorbent material form a very short packed bed, for example a packed bed with a length of 0.5 to 2.5 cm (note that the length is also called “thickness” when viewed from the direction of the gas flow passing through it), and the packed bed is arranged such that the gas flow to be separated passes through it. However, if such a bed is arranged in a single layer, the overall geometry of the adsorption system becomes very large and is technically and economically infeasible.

[0016] In contrast, embodiments of the present disclosure relate to the structure of a granular sorbent bed for gas separation by adsorption, which structure can achieve a very low pressure drop of the gas flow passing through the structure and a very high mass transfer rate between the gas phase and the surface of the sorbent material for efficient desorption. The basic underlying principle of the structure according to some embodiments of the present disclosure is that the particles of the sorbent material form a packed bed at a short distance through which the gas passes, for example, a distance of 0.1 to 2.5 cm, preferably 0.1 to 0.5 cm, and the packed bed is arranged such that the gas stream to be separated passes through. In some examples, a flexible porous material is provided that includes a short-distance packed bed that allows for small or variable particle sizes of the active material. In some examples, the flexible porous material has a first hydrophobicity that selectively excludes liquid components while a desorption medium (heat, steam) is applied. The flexible porous material enables the construction of a short-distance packed bed, in addition to moving a support structure outside the packed bed, and allows for the inclusion of the active material within the hydrophobic and flexible porous material or within a hydrophobic composite material that promotes compatibility. Other gains and advantages by implementing the features according to the present disclosure are provided herein.

[0017] A gas separation unit for separating a first gas, typically carbon dioxide, from a mixture comprising the first gas and at least one additional gas different from the first gas, typically air or exhaust gas, is proposed for use in a cyclic adsorption / desorption process and for use of a loose granular sorbent material for gas adsorption.

[0018] In the '039 Climeworks publication, the granular sorbent material is arranged in at least two stack layers, each layer being gas-permeable but comprising two sheets of a flexible fabric material that is impermeable to the loose granular sorbent material. These sheets are either attached to a rigid frame structure or form self-standing layers using spacers or distance elements between them, being arranged essentially parallel to define an inlet face of the layer and an outlet face of the layer, and being spaced at a distance in the range of 0.5 to 2.5 cm, surrounding a cavity in which the granular sorbent material is arranged. The proposed unit has a gas inlet side or gas inlet manifold where the inflow of the gas mixture enters the unit and a gas outlet side or gas outlet manifold where the gas outflow exits the unit, and the gas path between the inflow and the outflow is limited within the unit to pass through at least one layer. In other words, the gas entering the unit must pass through any one of the layers in any case, and there is no bypass under normal adsorption operation, and bypass can be permitted by corresponding valves for the cleaning and / or desorption process.

[0019] In the '039 Climeworks publication, the layers are arranged within the unit such that the inflow passes through the inlet face, then through the specific sorbent material arranged within the cavity of each layer, and then out of each layer through the outlet face (forming the gas outflow). Further, the inlet faces of adjacent layers face each other to surround a gas inlet channel, and the outlet faces face each other to surround a gas outlet channel. The average distance between the inlet face and / or the outlet face defining the channel (defined as the average of the distances across the facing surfaces of the entire surface) is in the range of 0.5 to 5 cm, measured in a direction essentially perpendicular to the main gas inflow direction and the main gas outflow direction respectively. Further, the length of the inlet face and / or the outlet face in a direction parallel to the main gas inflow direction and the main gas outflow direction is at least 10 times (or even 40, 50, 80, or 100 times) greater than the distance between the sheets within the layer.

[0020] The '039 Climeworks publication discloses that prior art units (see, e.g., WO2009 / 148872 A2 (Battelle Memorial Institute), U.S. Patent No. 6,379,437 (B1) (Valtion Teknillinen Tutkimuskeskus)) use a granular sorptive material embedded in a structured adsorbent bed through which the gas flow passes through linear flow-through channels. In these adsorbent bed configurations, the species removed from the gas flow by adsorption must be transported from the gas flow to the sorptive material by diffusion in a direction essentially perpendicular to the flow direction of the gas flow. The gas flow within these devices is not forced to pass through the corresponding sorptive material layer before exiting the device. However, when removing very low concentrations of species (such as CO2 in air) from the gas flow, the concentration gradient from the gas flow to the adsorbent bed is small, the achievable mass transfer rate is limited, a long residence time is required, and as a result, the process can become uneconomical.

[0021] In the structure disclosed in the '039 Climeworks publication, where the gas flow is guided and forced to pass through a channel wall composed of a granular sorptive material, the limitations of mass transfer by diffusion can be overcome, and for example, the mass transfer rate of CO2 from the air flow to the surface of the sorptive material can be significantly increased compared to the prior art. At the same time, the pressure drop across the structure of the '039 Climeworks publication can be kept low in contrast to the conventional packed column bed configuration.

[0022] Prior art, such as WO2009 / 148872A2 (Battelle Memorial Institute), depends on the adsorbed species diffusing from the main gas stream into the sorptive material layer. Therefore, the thickness of the sorptive material layer in these prior art structures is typically very small, preferably 3 mm, in order to minimize the limitations of mass transfer. However, the '039 Climeworks publication suggests that such thin sorptive material layers are costly to manufacture, delicate, and do not last long. The advantage of the examples disclosed in the '039 Climeworks publication is that the structure, which is easier to manufacture than those suggested by other prior art, i.e., a structure including a thicker sorptive material layer (e.g., 0.5 - 2.5 cm), is used in such a way that the mass transfer of the species adsorbed on the surface of the sorptive material is not impaired (since the gas stream passes through the sorptive material). This applies when diffusion-based prior art structures are implemented with a thicker and more easily manufacturable sorptive material layer.

[0023] The present disclosure improves this concept of the '039 Climeworks publication by configuring the layers of some embodiments to have external support features, thereby enabling the manufacture of thin sorptive material layers in an economical way and allowing easy filling without internal structures that impede the filling process. The external support features also enable the formation of sorptive material layers that are thinner than those suggested in the '039 Climeworks publication, e.g., 0.1 - 0.5 cm. Further advantages will be described later.

[0024] Additional prior art devices (e.g., WO2010 / 027929 A1 (Alstom Technology Ltd.), U.S. Patent No. 8,202,350 (B2) (SRI International)) utilize structures through which a gas stream can be induced to pass through a layer of a porous sorptive material, but these structures are based on an extruded monolithic structure which is essentially a two-dimensional structure extruded in three dimensions. In these structures, the sorptive material is not loose because it is in a monolithic structure, such as a gel-like structure, or a structure deposited on the channel walls. Further, the structure is typically extruded from a single material and in the extrusion process, it is not possible to construct the structure by combining any materials.

[0025] The '039 Climeworks publication suggests that the structure used therein has several advantageous features over other prior art extruded monolithic structures.

[0026] First, according to the '039 Climeworks publication, a structure based on an extruded monolith cannot represent a more complex three-dimensional structure, such as a stack of individual layers containing a loose, specific sorptive material surrounded by a flexible fabric sheet. This means that the prior art structures cannot represent the geometry of the '039 Climeworks structure, e.g., a heat transfer structure connected to a tube and embedded in a sorptive material layer surrounded by two layers of fabric material (see below).

[0027] In addition to the above, embodiments of the present disclosure further provide the advantage that the thermal conductivity and heat transfer properties are improved by implementing a sorptive article that is thinner than that disclosed in the '039 Climeworks publication. Embodiments of the present disclosure implement an external support structure that is completely external to the sorptive material layer and can support any layer or bed of loose granular adsorbent material, thereby eliminating the need to rely on an internal support (e.g., part of the frame 7 that defines the geometric structure of the sorbent layer 5 and internally supports the fabric material surrounding the sorptive material, as shown in FIG. 2 of the '039 Climeworks publication), and further providing the advantage that the structure can represent such a complex three-dimensional structure.

[0028] Second, according to the '039 Climeworks publication, prior art structures cannot be easily constructed from a combination of various different materials like the structure of the '039 Climeworks publication, and have corresponding advantages such as an optimized thermal mass / heat capacity and an optimized thermal conductivity of the heat transfer structure, which are detailed below in the '039 Climeworks publication. In particular, by incorporating a flexible fabric material surrounding the sorbent layer, in contrast to the prior art, (i) it becomes possible to use a flexible and somewhat extensible fabric sheet that holds the sorptive material in the form of a thin and uniform layer even when the volume of the particle layer contracts or expands to some extent during operation (e.g., due to drying and wetting of the material), and (ii) the fabric sheet can be adjusted to be impermeable to the sorptive material particles, very thin (0.5 - 2.5 cm thick), and have a very low pressure drop for the gas flow passing through the fabric sheet. In contrast, the fixed and hard channel walls of prior art monolithic structures (i) cannot adapt to a shrinking and / or expanding sorbent fill, and (ii) are typically either thicker than an optimized flexible fabric sheet or have lower porosity for the gas flow to pass through. This is because a higher density structure is required to maintain the rigid structure.

[0029] In addition to the above, embodiments of the present disclosure include sorptive articles that are thinner (0.1 to 0.5 cm thick) than those disclosed in the '039 Climeworks publication, and further provide the advantage of easily improving thermal conductivity / heat transfer properties. Thinner articles can also reduce the drying or wetting time of the material. The thinner sorptive material articles may be provided with a region or layer having a reduced porosity not only to make the article impermeable to sorptive material particles but also to foreign particles from the external environment. In some examples, by implementing an external support structure, a similar or improved thermal conductivity can be obtained without using an internal structure to support the loose particle adsorbent material.

[0030] Third, according to the '039 Climeworks publication, the prior art monolithic structure is likely to be exposed to a significant amount of flow that bypasses the layer of sorptive material, reducing the mass transfer rate during the adsorption process. This is because small cavities are likely to form in the sorptive material where a rigid structure such as the wall of the monolith contacts the sorptive material (e.g., during a filling or coating process). This reduces the resistance to air flow at these locations and induces a bypass flow. In the structure of the '039 Climeworks publication, the number of walls within the packing of the sorptive material can be maintained substantially lower compared to the prior art monolithic structure.

[0031] Fourthly, according to the '039 Climeworks publication, a combination of the proposed use of a loose granular adsorbent material combined with a flexible fabric for edging the layers and a stack arrangement having a specially selected layer thickness and channel width can provide a device that is highly efficient in the adsorption and desorption processes, very robust, has low pressure drop, is easy to handle, and has low manufacturing costs, and whose geometry can be specially adjusted to suit the needs of the process. This is in contrast to a monolithic structure where the sorptive material is provided in a solidified porous monolith shape rather than a loose shape. This structure is much more restricted throughout the manufacturing process, and due to the fixed local arrangement of the sorptive material within the channels or on their walls, manufacturing, cleaning, re-powering, etc. cannot be easily done. In particular, the stack unit of the '039 Climeworks publication can be substantially arbitrarily expanded in one direction perpendicular to the main direction of the gas flow (i.e., the stack direction) without complicating the manufacturing process. This is in contrast to the prior art extruded monolithic structure where an increase in the dimension perpendicular to the main direction of the gas flow requires a larger die plate.

[0032] Furthermore, the '039 Climeworks publication suggests further advantages of its structure over the prior art extruded monolithic structure due to the basic differences listed above in its structure.

[0033] According to the '086 Climeworks publication, the orientation of such a stack can be such that the planes of the individual layers are essentially horizontal planes. Thus, in this case, between the layers there are horizontal slots for the inflow of the gas mixture and horizontal slots for the outflow of the gas with reduced CO2. Such a substantially horizontal stack configuration can be selected to avoid the formation of holes within the layers due to the movement of the sorptive material during operation. Such holes can bypass most of the main air flow so as to be able to form regions where the pressure drop is significantly low.

[0034] In several examples of the '086 Climeworks publication, it is also disclosed that in such a substantially horizontal configuration, hole formation may also occur, and it has been observed that more controlled hole formation can be achieved in the vertical direction of the stack.

[0035] According to an embodiment of the '086 Climeworks publication, the layers can be arranged vertically, and the complete stack is rotated by 90° around the main horizontal axis of the whole unit, so to speak. According to this embodiment, at least two stack layers containing a granular sorbent material, or preferably all layers when there are more than two layers, each layer being gas-permeable but impermeable to the loose granular sorbent material, include two sheets of a flexible fabric material. These are oriented vertically, i.e., the plane normal of the layer is oriented horizontally. In other words, in this orientation between the layers, there are vertical slots for the inflow of the gas mixture and vertical slots for the outflow of the gas with reduced CO₂. Thus, any rearrangement / movement of the sorbent leads to a homogeneous bed due to the weight of the sorbent material and the corresponding downward movement of the particles plugging the holes formed in the self-alignment process. To avoid the holes formed at the upper end of the layer leading to bypasses, preferably slats made of aluminum are fixed in contact with the outer surface of the layer at the upper ends oriented along the upper ends of the inflow and outflow surfaces of the layer, covering a part of the layer (and the possible holes formed) to prevent inflow, and thus forcing all inflows through a layer of sorbent material containing sufficient sorbent particles in this area. The width of the slats ranges from 1 to 15 cm, preferably from 2 to 10 cm.

[0036] According to an embodiment of the '086 Climeworks publication, an intermediate rotational stack orientation is possible, where the plane normal is oriented in a plane perpendicular to the inflow direction, for example, in an orientation where the slots for the inflow of the gas mixture and the slots for the outflow of the gas with reduced CO₂ are between the horizontal and vertical directions, for example, at 45°.

[0037] In addition to the above, embodiments of the present disclosure further provide the advantage of being able to accommodate a loose granular adsorbent material by implementing an external support structure having an internal volume in which the loose granular sorptive material can be disposed. The external support structure can include a plurality of base portions and openings therebetween, as well as deflection portions or louvers, for example, to advantageously control the directionality of the inflow and outflow streams through the external support structure. Such controlled directionality promotes controlled drying or wetting of the loose granular adsorbent material, causing these particles to become uniformly wet and uniformly dry, facilitating a more efficient cycle process of adsorption and desorption, and enabling the particles to be used uniformly throughout, for example, allowing all of them to be replaced at once after a predetermined period of use.

[0038] In some examples, the base portions and deflection portions of the external support structure are formed from a continuous sheet of rigid material. In some examples, the external support structure forms a cheese lattice, louver, or fishnet configuration. In some examples, the plurality of base portions are separate components that are attached to or fixed to one another. In some examples, the loose granular sorptive material includes at least a first set of particles of a first size and a second set of particles of a second size smaller than the first size. In some examples, the first set occupies a first region within the internal volume and the second set occupies a second region different from the first region within the internal volume. In some examples, the external support structure has a tapered configuration.

[0039] According to a first preferred embodiment of the proposed unit of the '039 Climeworks publication, the length of the inlet face and / or the outlet face in a direction parallel to the main gas inflow direction and the main gas outflow direction, respectively, is at least 40 times greater than the distance between the sheets within the layer.

[0040] According to yet another preferred embodiment of the '039 Climeworks publication, the flexible fabric material is preferably a woven or non-woven textile material based on polymer fibers or yarns respectively, most preferably a woven or non-woven textile material based on fibers or yarns based on PET and / or PE respectively, or the flexible fabric material is cellulose-based and is made especially from paper material. The layer of flexible fabric material preferably has a thickness of 25 to 500 μm.

[0041] Embodiments of the present disclosure improve this concept of the '039 Climeworks publication by preferably providing a flexible non-woven material based on a polymer material, most preferably a microporous polymer material such as ePTFE or ePE. By using one or more of these materials, more advantages can be obtained than the '039 Climeworks publication which proposed the use of cellulose-based, especially paper materials. The non-woven microporous material of the present disclosure (for example, non-woven microporous ePTFE or ePE) can provide at least one of 1) hydrophobicity, 2) reduction of porosity, and / or 3) an inert and durable fabric material. For example, the reduction of porosity prevents particles larger than a predetermined size from passing through the layer. The layer of flexible non-woven material has a total thickness of 25 to 500 μm, preferably about 25 μm to about 50 μm, about 50 μm to about 75 μm, about 75 μm to about 100 μm, or any suitable value or range therebetween.

[0042] Preferably, according to the '039 Climeworks publication, more than 5 layers, preferably more than 10 layers, and most preferably more than 20 layers are preferably stacked essentially parallel to each other within the unit using a stack of corresponding frames and / or stacked at a relative inclination angle in the range of 0.2 to 15°, preferably in the range of 0.5 to 10°. In the latter case, the corresponding inlet channels can be arranged to converge in the main gas inflow direction, and the corresponding outlet channels can be arranged to diverge in the main gas outflow direction. In this case, the inlet channels are essentially closed at the downstream end by the side edges of adjacent layers (directly) contacting each other, and the outlet channels are closed at the upstream end by the side edges of adjacent layers. In other words, the layers are arranged in a zigzag pattern in a direction perpendicular to the gas flow as seen from the unit and parallel to the plane of the layers.

[0043] The layers of the '039 Climeworks publication can be essentially planar structures stacked essentially parallel to each other, or the layers can be essentially cylindrical or elliptical structures, most preferably arranged concentrically with each other.

[0044] The spacers of the '039 Climeworks publication can be arranged within the layers to define the distance between the layer surfaces. The spacers are preferably of a rigid bar or rail structure, most preferably of a T, H, C, or Z bar structure, or are provided by joints and / or seams between the sheets.

[0045] At least one layer, preferably most layers, and most preferably all layers of the '039 Climeworks publication can be provided, preferably in the form of tubes containing a heat exchange fluid, in combination with a secondary heat exchange element, most preferably to enhance the heat transfer between the sorbent material and the heat exchange element.

[0046] According to the '086 Climeworks publication, the primary heat exchange element can be a plurality of serpentine tubes for heat exchange fluid provided within a rigid rectangular peripheral frame structure and within a cavity, and all of the tubes on their non-bent portions are arranged essentially parallel to a first pair of mutually parallel metal profiles forming the rigid frame structure.

[0047] The tubes in the '086 Climeworks publication are arranged parallel to each other, essentially perpendicular to the main surface of the rigid frame structure, and can be in thermal contact with a secondary heat exchange element in the form of a plurality of metal sheets arranged perpendicular to the tubes (perpendicular to their non-bent portions). The tubes extend continuously between the first pair of mutually parallel metal profiles, and the secondary heat exchange element in the form of a metal sheet is provided with a plurality of holes through which the plurality of tubes pass.

[0048] The tubes of the primary heat exchange element in the '086 Climeworks publication are preferably metal tubes, preferably aluminum or copper tubes. These tubes can have an inner diameter in the range of 3 - 20 mm, preferably in the range of 5 - 12 mm, and / or an outer diameter in the range of 4 - 24 mm, preferably in the range of 6.2 - 14 mm.

[0049] The tubes of the primary heat exchange element in the '086 Climeworks publication are typically spaced at a distance (x) in the range of 10 - 168 mm, preferably in the range of 15.5 - 98 mm when running parallel.

[0050] The metal sheet forming the secondary heat exchange element according to the '086 Climeworks publication has a thickness in the range of 0.1 - 0.4 mm, preferably in the range of 0.12 - 0.18 mm.

[0051] The metal sheet forming the secondary heat exchange element according to the '086 Climeworks publication has a height (h) in the range of 3 - 50 mm, preferably in the range of 8 - 22 mm when measured perpendicular to the running direction of the tubes.

[0052] The metal sheet forming the secondary heat exchange element according to the '086 Climeworks publication has a length of less than 20 mm, preferably less than 5 mm shorter than the distance between each pair of metal profiles arranged parallel to each other forming the rigid rectangular peripheral frame structure.

[0053] The metal sheet in the '086 Climeworks publication is preferably made of aluminum.

[0054] Typically, the metal sheets forming the secondary heat exchange element in the '086 Climeworks publication are spaced at a distance (d) in the range of 1 to 6 mm, preferably in the range of 3.5 to 5.5 mm.

[0055] According to the '086 Climeworks publication, with respect to the dimensions of the tubes and the metal sheets, the above values allow for good interpenetration by the granular sorbent material and also allow for filling the structure in the manufacturing process, while providing sufficient porosity to the air passing through the layers and enabling the most efficient heat transfer process possible for the heating and cooling steps in the periodic temperature swing carbon dioxide recovery process.

[0056] According to the '086 Climeworks publication, the tubes forming the primary heat exchange pipes can also have, at least in part, a non-circular cross-section (flat shape). Very specifically, the first outer diameter of the cross-section of the pipe in a direction perpendicular to the plane of the layer of the rigid frame structure can be at least twice as large as the second outer diameter of the cross-section of the pipe in the longitudinal direction. By providing "slim" pipes in the plane of the layer of the rigid frame structure, pipes such as upright partition walls appear in the cavity, providing essentially a plane to the surface of adjacent pipes, enabling the most efficient attachment and heat exchange of the secondary heat exchange element in the form of a heat exchange metal sheet and / or sorbent, as detailed below.

[0057] The design of this flattened pipe according to the '086 Climeworks publication provides two substantial advantages for a heat exchange pipe with a circular cross-section. First, the area available for gas flow through the plane of the flexible fabric material sheet becomes much larger. This is because a smaller portion of the cross-sectional area of this flow is blocked by the pipe. Thereby, the pressure drop of the gas flow is reduced. Second, compared to the prior art designs using a circular pipe cross-section, the pipe spacing can be brought closer to each other, but the area available for gas flow remains large compared to those prior art designs. Thereby, the heat transfer distance through the sorptive material between the flattened pipes is reduced, optimizing the heat transfer design.

[0058] The flattened pipe in the '086 Climeworks publication can further be in thermal contact with a metal sheet forming a secondary heat exchange element, which is arranged essentially perpendicular to the main plane of the rigid frame structure, extends while vibrating between a pair of adjacent flattened pipes, and thereby contacts them for thermal contact. In other words, these metal sheets either vibrate in a wavy manner between adjacent flattened pipes to contact the flat small-diameter surface or vibrate in a zigzag manner between adjacent flattened pipes to contact the flat small-diameter surface.

[0059] Instead of or in addition to the metal sheet, as disclosed in the '086 Climeworks publication, a spacer arranged essentially perpendicular to the main plane of the frame and extending between at least a pair of adjacent flattened pipes can be used to hold the flattened pipes in a predetermined position.

[0060] In the '039 Climeworks publication, the main heat exchange element and / or the secondary heat exchange element can also function as a frame structure and / or a sheet. The primary heat exchange element and / or the secondary heat exchange element can be integrated into the frame structure, thereby strengthening the frame structure and preventing sagging. Further, the primary heat exchange element and / or the secondary heat exchange element can be combined with a fabric material to prevent swelling when filled with a sorptive material, and in certain combinations, can strengthen the frame structure.

[0061] The primary heat exchange element and / or the secondary heat exchange element of the '039 Climeworks publication can further be based on an expansion material, preferably an expanded metal, such as corrugated expanded metal.

[0062] The loose granular sorptive materials of the '039 Climeworks publication and the '086 Climeworks publication are preferably certain materials modified with amines, preferably cellulose-based, more preferably weak base ion exchange resins, specifically polystyrene matrix materials modified with amine groups, particularly primary amine groups, or amine-modified nanofibrillated cellulose, and in any case, preferably have an average particle size in the range of 60 to 1200 μm for carbon dioxide adsorption.

[0063] In comparison, the loose granular sorptive material of the present disclosure can be a certain material modified with amines, for example, having a particle size of 2 to 1200 μm, preferably a particle size of 5 to 50 μm, thereby reducing the total thickness of the sorptive material layer or its structure, and as further described herein, having the advantage of shortening the adsorption / desorption cycle time.

[0064] The frame of the '039 Climeworks publication is provided with holes filled with a loose specific sorptive material, and the holes are closed after the sorptive material is filled.

[0065] The unit of the '039 Climeworks publication can further include a surrounding enclosure or cage, preferably made of a flexible (such as a bag) or rigid (such as a frame cage) material, which is airtight except for the gas inlet opening for inflow and the gas outlet opening for outflow, preferably attached to a vacuum unit for the desorption process, and preferably the inlet opening and / or the outlet opening are provided with a controllable lid or valve for switching between the adsorption stage and the desorption stage. With this feature, the structure of the '039 Climeworks publication can be operated easily in a cyclic adsorption / desorption process where air flows through the lid or valve into the structure during adsorption, and the structure is sealed against the environment during desorption and can be exposed to heating and / or reduced pressure or increased pressure or to a different atmosphere such as a purge gas.

[0066] The sheets of each layer of the '039 Climeworks publication are preferably arranged at a distance in the range of 0.5 to 1.5 cm, and / or the average distance between adjacent inlet and / or outlet surfaces (i.e., the width of the channel), measured in a direction essentially perpendicular to the main gas inflow direction and the main gas outflow direction respectively, is in the range of 0.5 to 1.5 cm.

[0067] Furthermore, the '039 Climeworks publication relates to the use of such a unit for extracting carbon dioxide from air and / or flue gas from exhaust gas.

[0068] Further embodiments of the '039 Climeworks publication are described further below and are also described in the dependent claims.

[0069] The stack formed by multiple layers of the sorbent material in the ’039 Climeworks publication can have various geometric shapes, such as rectangular (Figures 1 and 6 of the ’039 Climeworks publication), cubic, or cylindrical (Figure 7 of the ’039 Climeworks publication). The gas inlet side where the gas flow enters the structure can be formed by a gas inlet manifold or can be open to the environment. The gas outlet side where the gas flow exits the structure can be formed by a gas outlet manifold or can be open to the environment.

[0070] According to one embodiment of the ’039 Climeworks publication, two layers of flexible fabric material surrounding the granular sorbent material are attached to a rigid frame structure (e.g., manufactured by injection molding of a plastic material) that forms the geometric shape of the sorbent layer (Figure 1 of the ’039 Climeworks publication).

[0071] According to another embodiment of the ’039 Climeworks publication, preferably two layers of flexible fabric material form the sorbent material layer by using several spacers or spacers between the two layers of fabric material without using a rigid structure. These spacers can have various geometric shapes and can be made of various materials. In one embodiment, the spacing holder can be a small plastic cylinder with a length equal to the thickness of the sorbent layer. In another embodiment, the spacer can be made from a filament yarn, and the two layers of fabric can be held together by sewing.

[0072] One of the advantages suggested by the examples disclosed in the ’039 Climeworks publication is that by stacking very thin sorbent layers (thickness 0.5 - 2.5 cm), the granular sorbent material can be arranged in a geometrically compact shape, and the length of the gas flow path through the sorbent material is relatively short. The ’039 Climeworks publication applies the principle of arranging a very large surface area in a compact shape of the stack, known from wall-flow monolithic structures, to a structure constructed from granular materials.

[0073] In addition to the above, embodiments of the present disclosure provide the further advantage of making the sorbent material more compact and further shortening the length of the gas flow path through the sorbent material by implementing a thinner material with a thickness of 0.1 to 0.5 cm, as disclosed herein. Further, the present disclosure provides the further advantage of a more controlled air path by providing a deflection portion or louver for controlling the directionality of the air path in the external support structure, thereby facilitating, for example, a shorter flow path than achievable by other methods.

[0074] For example, according to the '039 Climeworks publication, if the 1 m 3 sorbent material disclosed therein is placed in a single packed bed with a bed length of 1 cm, the bed cross-sectional area will be 100 m 2 , for example 10 m × 10 m. On the other hand, if the same amount of material is placed in 100 stack layers each having a thickness of 1 cm and an area of 1 m 2 and an inlet channel and an outlet channel with a width of 1 cm are arranged therebetween, the overall stack dimensions will be 1 m × 1 m × 2 m, which is much more compact and thus the installation area is much smaller. At the same time, the gas distribution becomes significantly easier with the stack arrangement. To evenly distribute the gas flow towards the bottom of a 100 m 2 large bed, excessive ducts are required, but the ducts required to direct the gas flow towards the inlet of a 1 m × 1 m × 2 m stack are relatively small. This consideration also shows, according to the '039 Climeworks publication, that in order to take advantage of the compactness of the stack arrangement, the length of the sorbent layer and the gas inlet and outlet channels in the main direction of the gas flow (parallel to the sorbent layer) need to be significantly larger than the thickness of the sorbent layer, for example at least 10 times larger.

[0075] Another advantage suggested by the examples in the '039 Climeworks publication is that, due to the fact that the structure is constructed as a stack of individual layers (in contrast to other prior art flow structures, for example, extruded or cast from a single material), the structure can be constructed from various materials and combinations of various materials. For example, the frame defining the geometry of the sorbent material layer can be made from a rigid, mechanically stable, lightweight material, and the two layers of preferably flexible fabric material surrounding the sorbent material layer can be made from different materials with the desired permeability characteristics for air flow and sorbent material particles. For example, the material forming the geometry of the sorbent material layer can be a rigid material, while the materials forming the two fabric layers surrounding the sorbent material layer can be flexible materials, thereby enabling various shapes of the sorbent material layer, such as a bag-like shape with a curved outer surface. Further, as outlined above, variations in the sorbent material fill volume due to shrinkage or expansion of the particles during the process can be compensated for. This enables several different shapes of the sorbent material layer that cannot be obtained with a rigid layer surrounding the sorbent material. At the same time, according to the '039 Climeworks publication, the heat transfer structure that can be accommodated in the sorbent material layer can be made from yet another material with favorable heat characteristics, such as a high thermal conductivity.

[0076] In addition to the above, embodiments of the present disclosure further provide the advantage of increasing the efficiency of the adsorption and desorption processes by using an external support structure to implement thinner individual layers. In this case, the external support structure can be rigid to provide support and is disposed entirely outside the individual layers. The external support structure is configured to control the directionality of gas flows, such as air paths and inflows / outflows through the layers, and can also improve the efficiency of the adsorption and desorption processes.

[0077] According to one aspect of the '039 Climeworks publication, a combination of materials that minimize the thermal mass of the overall structure can be used. The '039 Climeworks publication suggests that such a design is advantageous for reducing energy consumption when the structure is used within a cyclic temperature swing process. According to one preferred embodiment of the '039 Climeworks publication, the structure disclosed therein is used to extract CO2 from ambient air. In this preferred embodiment, the structure is operated in a cyclic adsorption / desorption process, during which air is passed through the structure during the adsorption step, and a portion of the CO2 contained in the air binds to the surface of the adsorbent material contained in the adsorbent material layer of the structure. Under typical process conditions, the adsorption step takes 2 hours, and on average, about 40% of the CO2 in the air stream is extracted, and about 0.3 moles of CO2 are adsorbed per 1 dm 3 of the adsorbent material. From these values, the velocity of the air Uair passing through the adsorbent layer can be determined as a linear function of the thickness d of the adsorbent layer, and is approximately as follows.

Equation

[0078] In addition to the above, embodiments of the present disclosure can shorten the time required for each adsorption / desorption cycle (e.g., less than 2 hours per cycle or less than 1 hour per cycle according to some embodiments) by, for example, using a thinner adsorbent material layer (e.g., 0.1 - 0.5 cm thick) as disclosed herein, using a hydrophobic material to form the material layer, and / or using an external support structure provided with means (i.e., deflection portions or louvers) for controlling the directionality of the inflow and outflow through the layer, thereby further providing the advantage of improving the cyclic temperature swing process.

[0079] At the same time, in a typical adsorbent material, the pressure drop Δp across the adsorbent layer is approximately a linear function of the air velocity and the thickness of the adsorbent layer as follows.

Equation

[0080] Therefore, the total pressure drop increases with the square of the sorbent layer thickness. When the thickness is 1 cm, the resulting total pressure drop is about 36 Pa, but when the thickness is 5 cm, it is about 900 Pa, which is already about an order of magnitude too large for economic DAC applications. At the lower limit, if the sorbent layer thickness is significantly less than 0.5 cm, the manufacturing cost becomes very high. This means that the preferred sorbent layer thickness being in the relatively narrow range of 0.5 - 2.5 cm is an important aspect of the '039 Climeworks publication.

[0081] In addition to the above, in embodiments of the present disclosure, in order to shorten the adsorption / desorption cycle time and increase the number of cycles that can be completed within a given time, as disclosed in the '039 Climeworks publication, a sorbent layer with a thickness of about 0.1 - 0.5 cm, which is thinner than the preferred thickness of 0.5 - 2.5 cm, is provided. The thinner sorbent layer may incorporate a granular sorbent bed containing smaller sorbent particles to shorten the cycle time and promote uniform wetting and drying of the sorbent particles. Such an advantage is, for example, being able to provide the same pressure drop Δp across the sorbent layer as disclosed in the '039 Climeworks publication.

[0082] As currently disclosed herein, a sorbent layer thickness of less than 0.5 cm, such as from 0.1 cm to 0.5 cm, advantageously has a thin wall, which facilitates including additional volume within the container for the sorbent material. For example, implementing a thinner sorbent material layer in the range of 0.1 cm to 0.5 cm makes it easier to reduce the pressure drop across the sorbent material layer. The thinner sorbent material layer is made possible by a denser microporous structure within the sorbent material, which in turn enables the use of smaller sorbent particles, and as a result, the layer thickness can be reduced without increasing the manufacturing cost, as claimed in the '039 Climeworks publication. In fact, when the thickness exceeds 2.0 cm, it can be disadvantageous because the pressure drop between two opposing surfaces of the sorbent material layer increases. For example, when the sorbent layer is thick, the use of a larger sorbent particle size may be required (this is to make it loosely packed so that air can pass through). Also, when the structure is thin, one or more of the following effects can be obtained: (a) promoting an increase in the diffusion of CO2 into the structure, (b) being able to place more panels of the thin sorbent within the volume, (c) optimizing the structure according to the mass of the sorbent and enhancing the efficiency of circulation, and (d) reducing the diffusion resistance for the same air flow rate passing through the structure. These larger particles have a smaller surface area and a lower kinetic potential than smaller particles of the same material. Microporous materials (such as ePTFE and ePE) enable the use of smaller particle sizes, have a large surface area with a thinner sorbent layer, and improved performance. For example, even if the thickness of the layer itself is less than 0.5 cm, end caps of an appropriate configuration can be provided or attached to the structure so that the sorbent material layer can be easily removed from the external support structure.

[0083] The application of the structure disclosed in the '039 Climeworks publication for CO2 extraction from the atmosphere is one preferred embodiment of the '039 Climeworks publication. The structure of the '039 Climeworks publication is used in other applications such as the separation of CO2 from flue gas, exhaust gas, industrial waste gas, or the separation of components other than CO2 from these or other gas streams.

[0084] According to one embodiment of the '039 Climeworks publication, the gas inlet channel and the outlet channel are formed by a rigid frame structure (e.g., manufactured by injection molding of a plastic material) that forms the geometry of the sorbent layer. Further, two layers of flexible fabric material surrounding the sorbent material are attached. One important function of the rigid frame structure in this embodiment is to provide a surface (such as rods, bars, or rail structures within the frame) sufficient to adhere or weld the flexible fabric material. Thereby, sufficient tension is applied to the flexible fabric material, and the sorbent material is held in a layer of relatively uniform thickness. The rigid frame structure can include spacers that fix the distance between the two frame structures, and this distance is at the same time the width of the inlet channel and the outlet channel between the two frame structures. The rigid frame structure can further include a structure that seals the inlet channel and the outlet channel towards the outside of the structure (excluding the inlet / outlet surfaces). The inlet channel and the outlet channel can be formed by stacking the frames on top of each other.

[0085] According to one embodiment of the '039 Climeworks publication, the layer of granular sorbent material is stacked in a zigzag as described above (Figure 2 of the '039 Climeworks publication). The advantage of this embodiment as suggested in the '039 Climeworks publication is the fact that the gas velocity in the gas inlet channel and the outlet channel is more uniform along the main flow direction of the gas stream than in the case of gas inlet channels and outlet channels of a constant width. This is because a part of the gas stream exits the inlet channel through the sorbent material layer, so the volumetric gas flow rate in the main flow direction along the gas inlet channel decreases. At the same time, a part of the gas stream enters the outlet channel from the sorbent material layer, so the volumetric flow rate in the main flow direction along the gas outlet channel increases. This embodiment ensures that the pressure gradient across the sorbent material layer in the structure of the present invention is more uniformly distributed, and thus the flow through the sorbent material layer is more uniformly distributed, guaranteeing that the sorbent material is most efficiently utilized during the adsorption process.

[0086] In addition to the above, embodiments of the present disclosure further provide the advantage of implementing a deflection portion or louvers on an external support to further improve the uniformity of the flow direction. The louvers can have different sizes and deflection angles across the entire frame. The dimensions and angles are derived from a fluid analysis of the gas flow within the system and through the sorptive material layer, thereby optimizing performance.

[0087] According to a preferred embodiment of the '039 Climeworks publication, the structure preferably includes a primary heat transfer structure and preferably a secondary heat transfer structure disposed within or on the side of the sorptive material layer ('039 Climeworks publication, Figure 3). The heat transfer structure can be made of a material with high thermal conductivity, such as a metal like copper or aluminum. For example, the secondary heat transfer structure can consist of one or more layers or sheets of a permeable structure disposed within the sorptive material. These sheets can consist of, for example, perforated metal, expanded metal, wire mesh, metal grid, or lattice. Additionally, the secondary heat transfer structure can consist of a honeycomb structure such as an aluminum honeycomb structure.

[0088] One possible secondary heat transfer structure used within the sorptive material layer of the '039 Climeworks publication and the '086 Climeworks publication is based on fins or metal sheets preferably aligned essentially perpendicular to the plane of the granular sorptive material layer. When the latter is aligned essentially horizontally, the fins are aligned vertically. When the granular sorptive material layer is essentially vertical, the fins or metal sheets of the secondary heat transfer structure are oriented horizontally. In this concept, the vertical fins forming the secondary heat transfer structure are preferably mechanically coupled to a primary heat transfer structure including or consisting of aluminum tubes.

[0089] Incorporating vertical fins perpendicular to the plane of the fabric material as a sorbent material layer and a secondary heat transfer structure within the frame is schematically shown in Figure 20 of the '039 Climeworks publication. First, since most fin-and-tube heat exchangers have heat transfer restricted on the gas side, they have a very large fin surface area that requires a narrow gap of about 1 mm between the fins. As determined by thermal simulation, the preferred conduction distance for the sorbent material used in DAC applications is about 3 - 8 mm or 5 mm, and as a result, the distance between the heat transfer structures is preferably in the range of 4 - 15 mm, more preferably 5 - 12 mm or 10 mm. The 5 - 12 mm or 10 mm spacing between the fins of the secondary heat transfer structure represents a good and preferred compromise between the thermal mass and heat transfer efficiency of the heat transfer structure, and thus makes these structures suitable for DAC applications. Furthermore, the typical spacing of about 1 mm between the fins used can limit the effective air flow cross-sectional area and can result in air flow velocities and pressure drops that may not be suitable for DAC applications. By widening the fin spacing of the secondary heat transfer structure to the above range, the effective cross-sectional area of the air flow passing through the sorbent material layer increases, the air flow velocity decreases, and the pressure drop across the sorbent material layer can be reduced to a level suitable for DAC applications. This can be an important requirement in some DAC applications.

[0090] Second, by incorporating fins as the second heat transfer structure into the frame, there is no restriction on heat transfer in the vertical direction, so the thickness of the sorbent material layer in the '039 Climeworks publication can be increased. Thus, as long as the pressure drop through the sorbent material layer is maintained within an acceptable range, the thickness of the sorbent material layer can be increased, thereby reducing the number of frames for a given stack height and the cost and heat mass of the stack per unit sorbent material. As shown in FIG. 20 of the '039 Climeworks publication, the tube diameter of the primary heat transfer structure can be made smaller than that of the sorbent material layer. In this configuration, the tubes do not bond to the fabric layer and form a number of separate sorbent cells within each frame. A positive result is that the sorbent can pass around the tubes, so that the frame can be filled with sorbent material through one hole in one corner. To support such a filling concept, holes are made in the vertical fins of the secondary heat transfer structure (10) (see FIG. 20a of the '039 Climeworks publication) to allow the sorbent material to pass between them. Thin perforated metal sheets are known, for example, from the manufacture of perforated metal honeycomb structures. Such a design typically represents a further improvement over the above-described planar secondary heat transfer structure located at the center of the frame, which limits the maximum sorbent layer thickness to about 10 mm. Further, in the current design, a plurality of sorbent material filling ports are required.

[0091] Thirdly, due to the fin spacing of the secondary heat transfer structure, the fabric material of the '039 Climeworks publication can be bonded to the fins at a short distance, preventing bulging under the weight of the filled sorbent. The positive result is that the inlet channel and the outlet channel are more clearly defined and have a more regular shape. This is in contrast to other designs where the fabric material can be bonded every 100 mm at most. Beyond this distance, bulging under the weight of the sorptive material is essentially unavoidable, and there is a possibility that the inlet / outlet channels will be blocked. By arranging the fins along the long edges of the frame and bonding them to the fabric material, further structural stability can be obtained. In this way, the fins of the secondary heat transfer structure function as a core with cross struts, transmitting the load to the tensioned fabric material. As a result, the rigidity and stability of the frame are significantly improved.

[0092] In the manufacturing technology of the fin-and-tube heat exchanger of the '039 Climeworks publication, the tube is placed in the holes of the fins, and the tube is locally expanded to cause plastic deformation in the tube and the fins, fixing the fins to the tube. Typically, one fin spans multiple passes of the tube. This is achieved by arranging the fins on a plurality of straight tubes, expanding the tubes, and connecting the tube segments with welded or brazed elbow connectors. In this way, a strong mechanical connection and a good thermal connection are realized in a multi-pass fin-and-tube heat exchanger. This process has already been industrially automated and can also be adapted for DAC applications.

[0093] An alternative process for creating the structure used in the DAC is described below and shown in Figure 21 of the '039 Climeworks publication. Similar to the conventional manufacturing process, the group of fins of the secondary heat transfer structure are attached to the tubes of the primary heat transfer structure at an interval "L" between the groups (Figure 21a of the '039 Climeworks publication). Conventional tube expansion techniques are applied to fix the fins to the tubes. Thereafter, the tubes with the fins attached can be bent into the shape of the primary heat transfer structure desired in the conventional frame design (Figure 21b of the '039 Climeworks publication). In the bent state, the fins are separated by small gaps, which does not result in a significant penalty for heat transfer to the sorbent. Since there are no fins at the bent portions, they can be arranged in the frame profile according to the current frame design. In this way, the tube fin heat exchanger can be constructed from a single continuous tube, and the processes of welding or brazing are not required.

[0094] Furthermore, the thicker sorbent material layer of the '039 Climeworks publication requires a thicker frame profile, which allows for a larger filling hole and significantly speeds up the filling of the sorbent material. For a 10 mm profile frame, the filling hole is 6 mm, and as a result, the inner diameter of the filling tube is 4 mm, which can significantly limit the flow of the sorbent material during filling and may lead to an increase in the filling time of the sorbent material. A frame thickness of 20 mm can support the use of a 16 mm filling hole with an inner diameter of 14 mm, for example.

[0095] Furthermore, the secondary heat transfer structure of the '039 Climeworks publication can consist of a granular material with good thermal conductivity mixed with the sorbent material.

[0096] The primary heat transfer structure of the '039 Climeworks publication can be housed within or connected to the secondary heat exchange structure and can be a tube through which a heat transfer fluid, such as water or a water / glycol mixture, can pass (Figures 3 and 4 of the '039 Climeworks publication). The tube can be, for example, a bent copper or aluminum tube, or a rubber or plastic hose. Through the heat transfer fluid, the heat transfer structure can be rapidly heated or cooled by an external heating or cooling source, such as a tank of high - temperature or low - temperature heat transfer fluid.

[0097] When the heat transfer structure is incorporated into a structure, it facilitates the operation of the unit of the '039 Climeworks publication within a cyclic adsorption / desorption process that includes heat swings. This is because the particulate sorptive material can be rapidly heated and cooled between individual steps of the adsorption / desorption cycle. The ability of the heat transfer fluid to transfer heat from and to the heat transfer structure as it passes through the tube typically allows for the incorporation of various heating and cooling sources available in the form of high - temperature or low - temperature fluid flows, providing an important interface to other processes or parts of a plant incorporating the unit of the '039 Climeworks publication.

[0098] Preferably, the heat transfer structure incorporated into the structure of the '039 Climeworks publication is in good thermal contact with substantially all portions of the granular sorptive material within the individual sorptive material layers, thereby minimizing the time taken for heating and cooling of the sorptive material. Preferably, the heat transfer structure is constructed such that it can heat or cool substantially all of the sorptive material by 75 K in less than 60 minutes, more preferably less than 20 minutes, and is incorporated into the structure of the '039 Climeworks publication.

[0099] When the primary heat exchange structure of the '039 Climeworks publication consists of tubes included in each layer, the ends of the tubes can be connected to the cylindrical elements included in each frame structure. When stacking the layers, these cylindrical elements are preferably connected to each other using O-rings and can form a backbone line for transferring the heat transfer fluid between the tubes within an individual layer. The backbone line formed from the individual cylindrical elements can have a diameter in the range of 1 to 5 cm. Further, the tubes of the primary heat exchange structure and the secondary heat exchange structure can be directly incorporated into the frame structure during an injection molding process. According to a further embodiment of the '039 Climeworks publication, the primary heat exchange structure of each sorbent layer can be coupled with a supply and return distributor of the heat transfer fluid connected to the supply and return lines of the heat transfer fluid. According to a further embodiment of the '039 Climeworks publication, the heat transfer structure disposed within the sorptive material layer forms part or the complete geometric shape of the granular sorptive material layer and / or functions as a support for a two-layer flexible fabric material surrounding the sorptive material layer. For example, the heat transfer structure can be made from corrugated expanded metal, and the bottoms and upper peaks of the corrugations function as attachment surfaces for the fabric material (Figure 5 of the '039 Climeworks publication). As another example, the heat transfer structure can be made from an aluminum honeycomb structure having the same thickness as the sorptive material. The two-layer fabric material can be attached to this honeycomb structure, for example, by glue adhesion or welding. The advantage of this embodiment as suggested in the '039 Climeworks publication is that since the heat transfer structure performs two functions simultaneously (heat transfer and support of the fabric layer), the amount of material required to form the exemplary structure of the '039 Climeworks publication is minimized. As a result, according to the '039 Climeworks publication, the thermal mass of the structure of this embodiment is minimized and the energy consumption for heating the structure is reduced.

[0100] In addition to the above, the present disclosure provides the further advantage of reducing even further the amount of material required to form the structure, particularly the sorptive material layer disposed within the structure, by implementing a sorptive material layer that is thinner, having a thickness of less than 0.5 cm (e.g., 0.1 cm to 0.5 cm), as compared to the sorptive material layer of the '039 Climeworks publication, where the preferred thickness of the sorptive material layer is, for example, 0.5 to 2.5 cm.

[0101] According to one embodiment of the '039 Climeworks publication, the sorptive material layer is rectangular, for example, a square with a side length of 1 m and a thickness of 1 cm, and the stack formed by the layer is, for example, in the shape of a rectangular block of 1 m×1 m×1 m (Figure 6 of the '039 Climeworks publication).

[0102] According to another embodiment of the '039 Climeworks publication, the sorptive material layer has a disk shape with a central hole, for example, a disk with a diameter of 1.5 m and a central hole with a diameter of 0.6 m, and the stack formed by the layer has, for example, a cylindrical shape with a diameter of 1.5 m and a length of 2.5 m (Figure 7 of the '039 Climeworks publication). In this embodiment, the gas inlet manifold can be formed by the stacked central holes, and the gas outlet manifold can have the shape of a ring located around the cylindrical stack.

[0103] According to yet another embodiment of the '039 Climeworks publication, the sorptive material layer has a concentric annular shape, and the stack formed by the layer has, for example, a cylindrical shape with a diameter of 1.5 m and a length of 2.5 m (Figure 8 of the '039 Climeworks publication).

[0104] According to one embodiment of the '039 Climeworks publication, the flexible fabric material layer surrounding the sorptive material layer simultaneously functions as a particle filter that retains particles, such as dust particles, in the inlet gas stream from the sorptive material. The '039 Climeworks publication suggests that this embodiment can be advantageous for applications where filtration of the inlet gas stream is required to protect the sorptive material, such as in the case of CO2 adsorption from the atmosphere. Thus, in this embodiment, no additional filtration structure is necessary. Since the surface area of the fabric sheet is very large and the flow velocity through it is relatively low (see above), the pressure accumulated on the sheet due to the dust load is relatively small.

[0105] In addition to the above, embodiments of the present disclosure further provide the advantage of retaining even smaller particles than what is possible with the '039 Climeworks publication by implementing a microporous material of non-woven fabric (e.g., microporous ePTFE or ePE of non-woven fabric) in the sorptive material layer to reduce the porosity of the layer and prevent foreign particles of a predetermined size from passing completely through the layer. The hydrophobic material of the present disclosure may also help prevent liquid water from entering the material layer while allowing water vapor to pass through.

[0106] According to one aspect of the '039 Climeworks publication, the pressure drop of the gas flow through the gas inlet channel and the outlet channel surrounded between the inlet surface and the outlet surface of the sorptive material layer can be made significantly smaller (preferably at least 5 times smaller, more preferably at least 10 times smaller) than the respective pressure drop of the gas flow through the sorptive material layer. The '039 Climeworks publication suggests that the advantage of this aspect is that the pressure gradient across the sorptive material layer is more evenly distributed, and thus the flow through the sorptive material layer is more evenly distributed, ensuring that the sorptive material is most efficiently utilized during the adsorption process.

[0107] In addition to the above, embodiments of the present disclosure further provide the advantage of improving the uniformity of the flow direction by controlling the directionality of the inflow and outflow through the sorptive material layer, for example, using a deflection portion or a louver provided in an external support structure.

[0108] According to one embodiment of the '039 Climeworks publication, at least a part of the elements (e.g., reinforcing materials / rods) of the rigid frame structure that support the two-layer fabric material located inside the sorbent layer has the shape of an H, C, or Z profile, or a similar shape. The '039 Climeworks publication has the advantage that this example can reduce the recirculation flow that may occur at the edges included in the sorbent layer, which bypasses the bulk layer of the sorptive material. This is because the potential recirculation flow path is significantly longer than in the case of the linear elements in the sorbent layer ('039 Climeworks publication, Figure 9).

[0109] In addition to the above, the present disclosure further provides the advantage that by implementing an external support structure, the thickness of the sorptive material layer can be reduced to less than 0.5 cm (e.g., 0.1 cm to 0.5 cm, which is thinner than the thickness of 0.5 cm to 2.5 cm disclosed in the '039 Climeworks publication). Implementing the external support structure is done by implementing an external support structure that is completely disposed outside the sorptive material layer (rather than having the support material disposed inside the sorptive material layer, such as the reinforcement / rod in the '039 Climeworks publication), and can include, for example, a deflector portion or louvers provided to control the direction of the gas flow passing through the external support structure. Advantageously, in the present disclosure, since there is no internal frame structure (e.g., H, C, or Z profile members as disclosed in the '039 Climeworks publication), the "recirculation flow that bypasses the bulk layer of the sorptive material" disclosed in the '039 Climeworks publication is likely to occur, and the number of edges included in the sorbent layer that causes the formation of leak paths is reduced. By reducing the number of edges, the possibility of leak paths occurring within the structure is advantageously lowered. The '039 Climeworks publication attempts to minimize this harmful effect by utilizing an internal structure with a longer path, but with the concept of the external support in the present disclosure, this problem is completely eliminated.

[0110] According to one embodiment of the '039 Climeworks publication, the sorptive material layer and the fabric material layer surrounding them are constructed such that the sorptive material is filled into the layer through one or more holes (preferably at the edge of the sorptive material layer). In this embodiment, the elements of the rigid frame structure (e.g., reinforcement / rod) that support the two-layer fabric material and are located inside the sorbent layer and may form individual cells within the sorptive material layer have one or more holes through which the preferably granular sorptive material with good fluidity can pass between the cells during the filling process. Also, when the heat transfer structure is made of a honeycomb structure, the walls of the individual cells of the honeycomb structure can include holes for interconnecting the cells and facilitating filling of the structure with the granular sorptive material.

[0111] In comparison, in the embodiments of the present disclosure, the external support structure of the sorptive material layer is constructed or configured such that the structure of the sorptive material layer can be filled with sorptive material particles, preferably through one or more holes, preferably at the edges of the structure, or can be filled from the end by providing hinged or removable end caps. The external support structure of the layer provides significant advantages over the '039 Climeworks publication by eliminating the need to implement thicker layers and internal reinforcements. When there are internal reinforcements in the layer as disclosed in the '039 Climeworks publication, the sorptive material particles need to loop around and pass through different regions within the sorptive material layer.

[0112] According to one aspect of the '039 Climeworks publication, the method of manufacturing a sorptive material layer preferably consists of filling a layer confined between two layers of fabric material with granular sorptive material through one or more holes, preferably at the edges of the sorptive material layer, and it is preferred to utilize pressurized air for the filling process.

[0113] In contrast, in the embodiments of the present disclosure, the granular sorptive material can be filled from hinged or removable end caps of the external support structure. It should be understood that the ability to easily remove the sorptive material (for eventual replacement) is an important aspect of the sorbent bed structure as disclosed herein. With hinged or removable end caps, the material can be poured out, for example, by tilting the module or structure. Since there are no internal obstructions within the external support structure as disclosed herein, the sorptive material can be relatively easily and efficiently removed, replaced, or distributed within the module or structure.

[0114] According to one embodiment of the '039 Climeworks publication, an enclosure or cage surrounding a stack of sorptive material layers is supported by the stack and carries the vacuum force externally imposed on the container under specific process conditions.

[0115] According to one embodiment of the '039 Climeworks publication, the lid or valve that opens and seals the gas inlet side or gas inlet manifold and the gas outlet side or gas outlet manifold can open over at least 50%, preferably at least 75%, more preferably at least 90% of the front area of the stack (as viewed from the direction of gas flow).

[0116] One aspect of the '039 Climeworks publication includes a cyclic adsorption / desorption process for removing components from a gas stream using the aforementioned unit. In one preferred embodiment of the '039 Climeworks publication, this unit is used in a process for removing CO2 from air using an amine-based sorbent material.

[0117] In a typical cyclic adsorption / desorption process using such a unit according to the '039 Climeworks publication, adsorption can be carried out under ambient conditions, for example, in a temperature range of -30 to 40 °C and an absolute pressure of 0.7 to 1.3 bar. After the adsorption of carbon dioxide or carbon dioxide and water vapor, the sorbent material is heated, for example, to 50 to 120 °C, and the absolute pressure is reduced, for example, to 1 to 250 mbar abs by applying a vacuum, i.e., by reducing the partial pressure of CO2 around the sorbent material, and / or by exposing the sorbent material to a purge gas stream, the sorbent material can be regenerated or desorbed. When desorption is achieved by heating the sorbent material and applying a vacuum, the overall cyclic process is called a temperature-vacuum swing (TVS) process. When desorption is achieved by heating the sorbent material and exposing it to a purge gas stream, the overall cyclic process is called a temperature-concentration swing (TCS) process.

[0118] In one preferred embodiment of the '039 Climeworks publication, the structure is used in a TVS process for removing CO2 from ambient air.

Brief Description of the Drawings

[0119] Brief Description of the Drawings Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. The drawings are intended to illustrate the currently preferred embodiments of the present disclosure and are not intended to limit the same. In the drawings,

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DETAILED DESCRIPTION OF THE INVENTION

[0159] Detailed Description Definitions and Terms The present disclosure is not intended to be construed in a limiting sense. For example, the terms used in this application should be broadly construed in relation to the meanings given to such terms by those skilled in the art.

[0160] With respect to incorrect terms, the terms "about" and "approximately" can be used interchangeably to refer to a measurement that includes the recited measurement value and measurement values reasonably close to the recited measurement value. A measurement value reasonably close to the recited measurement value deviates from the recited measurement value by a reasonably small amount as would be understood and readily ascertainable by a person of ordinary skill in the relevant art. Such deviations can be due to, for example, measurement errors, differences in calibration of measurement and / or manufacturing equipment, human error in reading and / or setting of measurement values, minor adjustments made to optimize performance and / or structural parameters in view of differences in measurement values related to other components, particular implementation scenarios, inaccurate adjustment and / or manipulation of objects by persons or machines, and / or the like. If it is determined that a person of ordinary skill in the relevant art cannot readily ascertain the value of such reasonably small differences, the terms "about" and "approximately" can be understood to mean plus or minus 10% of the recited value.

[0161] As used herein, the term "fibril" refers to a piece of elongated material, such as a polymer, having a length and width that are substantially different from each other. For example, a fibril can be similar to a string or a fiber piece having a width (or thickness) that is much shorter or smaller than its length.

[0162] As used herein, the term "node" refers to a connection point of at least two fibrils, and the connection can be defined as a location where two fibrils come into contact with each other either permanently or temporarily. In some examples, a node can also be used to represent a material having a volume larger than that of the fibril, and the fibril can start or end at the node without the same fibril continuing clearly through the node. In some examples, a node has a width greater than its length and a length shorter than that of the fibril.

[0163] As used herein, "nodes" and "fibers" are used to represent objects that are normally connected or interconnected, but not necessarily so, and can be used, for example, to represent objects of microscopic size. A "microscopic" object is one in which at least one dimension (width, length, or height) is substantially small, and the object or details of the object are not visible to the naked eye, or, even if not impossible, are difficult to observe without the aid of a microscope (including, but not limited to, a scanning electron microscope or SEM) or any suitable type of magnifying device.

Example

[0164] Example 1. Example of the '039 Climeworks publication in the form of a rectangular stack According to one example as disclosed in the '039 Climeworks publication, the structure is composed of rectangular sorptive material layers stacked on top of each other to form a stack in the shape of a rectangular block including an inlet channel, an outlet channel, and a sorbent layer. In this example, the manufacture and assembly of this example are described to show the applicability of the present invention in the form of a product useful for CO2 extraction from ambient air.

[0165] Each sorptive material layer of the '039 Climeworks publication is formed by a rigid frame structure including a rectangular frame having a side length of 0.5 m × 0.6 m and a height of 1 cm made from a stainless steel profile. A top view of such a single frame is shown in FIG. 10 of the '039 Climeworks publication, and each cross-section is shown in FIG. 11 of the '039 Climeworks publication. The manufacture and assembly of the overall structure include the following steps: 1. The frame structure is manufactured by welding stainless steel profiles (for example, in the case of mass production, a frame structure having the same function can also be manufactured by injection molding of a plastic material or aluminum, thereby significantly reducing the manufacturing cost). 2. Insert a rubber tube containing an aluminum wire mesh and a heat transfer fluid into the frame to ensure good heat transfer. 3. Use a two-component adhesive to bond the layer of non-woven material to both sides (upper and lower) of the frame structure. 4. The sorptive material based on amine-modified cellulose fibers is manufactured according to a scaled-up version of the procedure disclosed in WO2012168346A1: a. Separation of cellulose nanofibers from a purified fibrous beech pulp suspension (see "1. Separation of cellulose nanofibers" in WO2012168346A1). b. Add a solution of hydrolyzed 3-aminopropylmethyldiethoxysilane to the nanofiber suspension with a dry mass content of 3.2%. c. Homogenize the solution and stir for 2 hours. d. Freeze the solution batchwise in a copper mold in liquid nitrogen. e. Lyophilize the frozen mixture for 48 hours. f. Treat the dried material in an oven under an argon atmosphere at 120 °C. g. Compress and grind the material to obtain a granular sorptive material with an average particle size of about 400 μm. 5. Fill the sorptive material through the holes into the frame structure and then close the holes. 6. Obtain a stable layer of the sorptive material layer. The thickness varies in the range of 1 - 1.5 cm. 7. A total of 26 frames are stacked on top of each other, and spacers form the inlet channel and the outlet channel. 8. Mount the stack in a rectangular vacuum chamber with internal dimensions of 0.55 m × 0.55 m × 0.65 m, equipped with inlet and outlet openings for air flow. 9. Connect a pneumatically actuated butterfly valve to each opening to seal and open the chamber to the environment. 10. Connect the inlet opening to a fan for generating an air flow during adsorption. Furthermore, connect the chamber to a vacuum pump for reducing the pressure during desorption and a thermostat for heating and cooling the stack during individual cycle steps.

[0166] According to the '039 Climeworks publication, within the stack of this example, the total surface area of the sorbent material layer facing the gas inlet channels is approximately 8 m 2 It is. The designed air flow rate through the chamber is 800 m per hour 3 However, the average velocity of the air flow through the sorbent layer is as low as 0.028 m / s. This results in a very small pressure drop (see Example 2 of the '039 Climeworks publication below).

[0167] In FIG. 1 of the '039 Climeworks publication, a schematic diagram of the principle of the embodiment of this example is shown. In FIG. 6 of the '039 Climeworks publication, a 3D view of a stack including 26 sorbent material layers is shown. In FIG. 10 of the '039 Climeworks publication, a top view of one of the frame structures composed of a C-profile 17 and a Z-profile 12 is shown. In FIG. 11 of the '039 Climeworks publication, a cross-section through the frame structure is shown.

[0168] Example 2. Determination of the pressure drop through the stack of sorbent layers According to the '039 Climeworks publication, the pressure drop imposed on the air flow passing through a structure essentially manufactured according to the description of Example 1 of the '039 Climeworks publication is determined experimentally for various flow rates. For this purpose, both butterfly valves are opened, a variable speed fan is attached to the inlet opening, and various air flow velocities through the stack are generated. The flow velocity is measured with a velocity head meter in the pipe, and the pressure drop across the structure is measured using a differential pressure sensor. The pressure drops observed for various volumetric flow rates are shown in the following table.

Table 1

[0169] According to the '039 Climeworks publication, the design flow rate of 800 m required to capture approximately 1 kg of CO2 from the air per cycle 3Up to / h (see Example 3 of the ’039 Climeworks publication), the pressure drop remains below 100 Pa. When the average pressure drop during the adsorption process is 100 Pa, the pump work required to capture 1 ton of CO2 from the atmosphere is approximately 80 kWh (assuming that on average 70% of the CO2 is captured from the air stream and the fan efficiency is 70%). This energy consumption corresponds to an electricity cost for air ventilation of $8 per ton of CO2 (assuming an electricity cost of $0.1 per kWh), which is within an acceptable range. However, when the pressure drop is as high as 500 Pa, the corresponding electricity cost of $40 for air ventilation exceeds the acceptable limit of an economic process.

[0170] The ’039 Climeworks publication suggests that the above shows the advantages of the structure of the examples disclosed therein over conventional arrangements of granular sorbents, such as packed beds or fluidized beds, which are much longer than the sorbent filling of the ’039 Climeworks publication and typically result in pressure drops from several thousand Pascals to several bar.

[0171] In addition to the above, embodiments of the present disclosure further provide the advantages of a more compact configuration of a packed bed of granular sorptive material by implementing an external support structure having an internal volume in which the granular sorptive material can be disposed, and since the thickness is defined by the external support structure, the material can be supported while reducing the thickness of the packed bed (or sorbent layer).

[0172] Example 3. Performance of Example 1 in the cyclic adsorption / desorption process According to the ’039 Climeworks publication, a structure essentially manufactured according to the description of Example 1 of the ’039 Climeworks publication is used in a cyclic temperature-vacuum swing adsorption / desorption process for extracting CO2 from ambient air. One cycle of the process takes about 6 hours and includes the steps of adsorption (3 hours) and desorption (3 hours).

[0173] During the adsorption process of the '039 Climeworks publication, according to Example 2 of the '039 Climeworks publication, the butterfly valve is opened, and air is blown into the structure by a variable-speed fan, during which the flow rate is recorded. Further, an infrared detector is used to measure the CO2 content and its relative humidity of the air flow before and after the vacuum chamber. The relative humidity during the adsorption process is relatively constant between 35% and 40%. The air flow rate is 750 - 800 m 3 / h. The CO2 concentration (the "adsorption breakthrough curve") before and after the chamber during adsorption is shown in Figure 10 of the '039 Climeworks publication.

[0174] According to the '039 Climeworks publication, first, during the first few minutes of the adsorption process, the CO2 concentration at the outlet of the chamber drops to almost 0 ppm. This indicates that the structure of this embodiment has very excellent performance. This is because the disappearance of the CO2 concentration indicates that almost all of the air flow passing through the structure effectively passes through the adsorbent material layer and does not bypass it. If there was a substantial bypass flow, this bypass flow would still contain approximately 400 ppm of CO2 and would be mixed with a part of the flow passing through the adsorbent material layer, and the CO2 concentration at the chamber outlet would have increased.

[0175] The '039 Climeworks publication suggests that the behavior of this system is substantially superior to the behavior observed in an experiment using a short packed bed of adsorbent material with a length of 1 cm in a conventional stainless steel column with a diameter of 4 cm. In that experiment, the outlet CO2 concentration did not reach as low a value as observed in this example, which is probably because the bed was not fixed between two layers of fabric and bypass could occur along the column wall, so the flow was bypassed.

[0176] In particular, the '039 Climeworks publication suggests that, with the structures disclosed in the examples disclosed herein, embodiments based on 3D structures can be created that exhibit advantageous behavior during operation and that include different materials that cannot be created from conventional extruded 2D structures.

[0177] In addition to the above, embodiments of the present disclosure further provide the advantages of a more compact 3D structure of the packed bed of the granular sorptive material by implementing an external support structure having an internal volume in which the granular sorptive material can be disposed. Advantageously, since the thickness is defined by the external support structure, the thickness of the 3D structure can be reduced to less than 0.5 cm (e.g., 0.1 - 0.5 cm, which is thinner than the thickness or length of 1 cm of the sorptive material mentioned above in the '039 Climeworks publication).

[0178] Furthermore, the '039 Climeworks publication suggests that this example shows that with the proposed structure, a substantial portion of the CO2 contained in the air stream can be extracted using a granular amine-modified sorptive material with a pressure drop of less than 100 Pa, and that the structure can be manufactured with reasonable effort.

[0179] During the subsequent desorption step in the '039 Climeworks publication, the vacuum chamber is at about 100 mbar absEvacuate until, and then heat the stack to about 85 °C by circulating warm water through the plastic tube. Thereafter, continuously pump out the CO2 desorbed from the sorbent material from the chamber by a vacuum pump. Measure the mass flow rate of the CO2 exiting the vacuum pump using a calorimetric mass flow meter. See Figure 13 of the '039 Climeworks publication. Also measure the CO2 concentration using an infrared sensor. See Figure 14 of the '039 Climeworks publication. After the air initially still contained in the system has been purged out, it is observed that after a desorption time of about 30 minutes, the CO2 concentration reaches the saturation limit of the sensor, indicating that the resulting CO2 concentration exceeds at least 99%. During the complete desorption process of the '039 Climeworks publication, about 1 kg of CO2 is recovered. Thus, this example further shows that the structure of the '039 Climeworks publication has been successfully applied to extract CO2 with a purity exceeding 99% from the atmosphere.

[0180] Example 4. Example of triangular gas inlet and outlet channels According to the '039 Climeworks publication, another structure is manufactured in which the gas inlet and outlet channels between the sorptive material layers have a triangular cross-section. For this purpose, 20 frame structures each defining a sorptive material layer 2 cm thick are produced by injection molding of a thermoplastic material. During the injection molding process, an aluminum tube and a heat transfer structure composed of an aluminum honeycomb structure with a cell width of 1 / 2 inch are integrated into the frame structure, and each of the six side walls of each cell contains a central hole with a diameter of 4 mm. Each frame further has a triangular edge at the top that defines the distance between two stacked frames, thereby defining the shape of the gas inlet and outlet channels. After the molding process, a woven fabric material made from a mixture of PET fibers and PE fibers is adhered to both sides of the frame, and the frame is filled with a sorptive material in the same filling process as described in Example 1 of the '039 Climeworks publication. During the filling process, the sorptive material passes through the network of cells of the aluminum honeycomb structure through the holes in the side walls of the honeycomb cells. Then, the 20 frame structures are stacked on top of each other to form a stack with a cross-section as schematically shown in FIG. 2 of the '039 Climeworks publication.

[0181] Example 5. Use in a flue gas CO2 recovery process According to the '039 Climeworks publication, the CO2 contained in the flue gas flow of a natural gas-driven combined heat and power internal combustion engine is recovered using a stack of sorptive material layers contained within a vacuum chamber similar to the stack described in Example 1 of the '039 Climeworks publication.

[0182] According to the '039 Climeworks publication, in this case, the CO2 concentration of the gas flow passing through the structure is approximately 6%. The gas volume flow rate during adsorption is substantially low, in the range of 20 - 30 m 3 / h. The adsorption process takes 0.5 hours, and on average 90% of the CO2 contained in the gas flow is extracted.

[0183] According to the ’039 Climeworks publication, the desorption process takes one hour, during which CO2 is removed from the sorbent material by heating the sorbent material to 95 °C. Three units (one unit consists of one stack contained within a vacuum chamber) are operated in tandem, with one stack in the adsorption mode and two stacks in the desorption mode at any given time, enabling continuous capture of CO2 from the flue gas stream.

[0184] Example 6. Effect of the heat exchange structure disposed within the sorbent material According to the ’039 Climeworks publication, to demonstrate the effectiveness of the heat transfer structure incorporated within the sorbent material layer in an experiment, a packed bed of 100 g of sorbent material (see Example 1 of the ’039 Climeworks publication) is placed in a rectangular packed bed aluminum reactor with a cross-section of 60 mm × 60 mm. After 3 hours of adsorption with air at a relative humidity of 60% flowing through the reactor at 20 l / min, the reactor is evacuated to 100 mbar abs using a vacuum pump, and the walls of the reactor are heated to 90 °C with a water-filled jacket to desorb the sample. During the desorption process, the temperature at the center of the bed is recorded. In this experiment, it takes 221 minutes for the temperature at the center of the bed to reach 80 °C.

[0185] Subsequently, according to the ’039 Climeworks publication, to enhance heat transfer, the experiment is repeated by placing 6 g of an aluminum honeycomb structure with a cell width of 3 / 4 inch in the sorbent material bed. In this experiment, it takes 79 minutes for the temperature at the center of the bed to reach 80 °C.

[0186] The ’039 Climeworks publication claims that this observation demonstrates the effectiveness of the heat transfer structure contained in the sorbent material bed, significantly shortening the time required to heat the sorbent material bed during the desorption process, thereby reducing the overall cycle time and the cost of the entire adsorption process.

[0187] In the ’039 Climeworks publication, this example claims to further show another advantage that the structures disclosed in the examples disclosed therein are superior to other prior art structures because a 3D structure that enhances heat transfer contained within a sorbent material layer, such as an aluminum honeycomb, cannot be easily incorporated into a prior art extruded 2D structure.

[0188] In addition to the above, the present disclosure further provides the advantage that by implementing an external support structure as disclosed herein, the thickness of the sorbent layer is reduced and the directionality of the air flow passing therethrough is controlled. Further, the absence of an internal support structure (e.g., the aforementioned honeycomb structure of the ’039 Climeworks publication) in the sorbent layer also provides an additional advantage that there is no internal structure that could potentially impede processes such as emptying or refilling the sorbent layer.

[0189] Example 7. Example of the form of a rectangular stack illustrating possible dimensions of the frame and stack and stack assembly Taking into account the requirements regarding pressure drop, in accordance with the ’039 Climeworks publication, the maximum thickness of the sorbent material layer was defined as 1 cm, the height of the inlet channel was 1 cm, and the lengths of the inlet channel and the outlet channel were defined as 1 m. Due to structural reasons, the vacuum chamber in which the adsorption structure is housed was defined to contain 500 - 1000 kg of sorbent material. As a result, it was found that the width of the frame is 1.45 m. The frames are stacked on top of each other in a “zigzag” pattern with an angle of 2° between the planes. In this pattern, the dead volume (i.e., the volume of the stack not occupied by sorbent material) is reduced by 40% compared to a stack with parallel channels and the same inlet channel height. The reduction in dead volume improves cost efficiency and process efficiency by packing more sorbent material into a given volume, thereby producing more CO2 from a given facility. As a result, the height of the stack is 1.47 m with 88 sorbent material frames.

[0190] In FIG. 15 of the ’039 Climeworks publication, the frame 5 is shown separated by wedge-shaped spacers 23 adhered to the frame along the edge of 1 m. These wedge spacers create the angle of the channel and serve to seal the side channels. Each wedge spacer is directed towards the head 24 of a screw fixed to the frame at the thick end. Each spacer passes a screw 25 through the adjacent frame and is attached to the next lower wedge spacer and also fixed to the adjacent frame. The wedge spacers are adhered to the frame with double-sided tape to provide a uniform bond. The sealing strips 8, 9 seal the channels and form an inlet channel and an outlet channel respectively through which the air flow 1 must pass. This assembly strategy allows for a high degree of modularity and adaptability of the stack, in contrast to the extraction monolith or welded structures used in the prior art. Single or multiple frames can be added, removed or replaced economically without affecting the performance of the entire stack.

[0191] In FIG. 16 of the ’039 Climeworks publication, a stack is shown as viewed from the direction of the inlet channel. The wedges 26 arranged on the primary heat transfer structure support the profile of the inlet channel to prevent sagging and maintain the desired width of the inlet channel. To keep the height of the stack of 88 frames constant, the overall height of each stack component needs to be within an acceptable range. Furthermore, the bond between the fabric material and the frame and wedges and sealing strips needs to be constant and homogeneous. For example, if there is a tolerance of 0.5 mm in the thickness of the adhesive bead for each frame, the position and height of the stack of 88 frames will shift by a total of 4.4 cm, and as described in Example 10 of the ’039 Climeworks publication, the connection to the heat transfer fluid system is put at risk. Therefore, double-sided tape with a thickness of 0.22 mm is used. The tape provides a consistent bond thickness and strength, can withstand the maximum temperature of 120 °C imposed by the desorption process, facilitates repair and overhaul, and shortens the assembly time compared to adhesives.

[0192] According to the Climeworks publication of '039, the same principles of stack layout and assembly described in this example can be applied to various other stack shapes, not limited to, for example, a small stack with fewer frames, different frame dimensions, and a stacking layout without angles, that is, a stack composed of frames that are essentially parallel to each other, with no angles between the surfaces, that is, no "zigzag" structure.

[0193] Example 8. Low heat mass frame Reducing the thermal mass of the frame per unit mass of the sorptive material contained reduces the overall energy requirement of the desorption process and is an important parameter in the design of DAC systems. The desorption process is carried out in a vacuum structure and is subject to vacuum forces, so the frame itself has to support only its own weight, the weight of the sorptive material, and the weight of the heat transfer structure, while ensuring the desired geometry of the inlet and outlet channels and the sealing surfaces. According to the '039 Climeworks publication, an example of such a frame was constructed from four aluminum C-profiles with an outer dimension of 10 x 10 mm and an inner dimension of 8 x 8 mm, connected with edge brackets to form a rectangular shape. The primary heat transfer structure was formed by 10-pass 8 mm OD aluminum tubes placed inside the C-profiles, passing through the C-profiles at two locations to enable connection to a water distributor. In this way, the stability of the primary heat transfer structure is ensured without adding frame parts. The aluminum tubes (primary heat transfer structure) significantly contribute to the rigidity of the entire frame. The secondary heat transfer structure is formed from expanded aluminum sheet metal, formed on the primary heat transfer structure as shown in Figure 5 of the '039 Climeworks publication, and adhered in place. The fabric material is adhered between the C-profiles at the edges of the frame to form a closed, breathable space that can be filled with the sorptive material. To prevent it from bulging when filled with the sorptive material, the fabric material is tensioned and adhered to the tubes of the primary heat transfer structure and the edge profiles of the frame. This forms cells with dimensions of 1 m x 0.1 m for filling with the sorptive material. Each cell is provided with a sealable hole at one corner of the C-profile to allow filling with the sorbent.

[0194] According to the '039 Climeworks publication, in the feasibility of frame design, the thermal mass of the components that have to be thermally cycled during the cyclic adsorption-desorption process is a determining factor. The contribution of each element and the total thermal mass of the frame per unit mass of the sorptive material contained are shown in detail in the following table. The mass of the sorbent contained is 7.25 kg.

Table 2

[0195] ’039 According to the Climeworks publication, an exemplary sorbent suitable for CO2 recovery from ambient air has a specific heat capacity of 1.4 kJ / K / kg sorbent, and the desorption specific heat for CO2 and water is 211 kJ / kg sorbent. In a typical desorption process, the sorptive material must be heated from an adsorption temperature of 20 °C to 100 °C. The total heat energy requirement in this typical desorption process can be determined to be 323 kJ / kg sorptive material. The heat energy requirement for the frame in this scenario is 30.2 kJ / kg sorptive material, which is 9.3% of the total heat energy requirement.

[0196] Example 9. Heat transfer structure and its dimensions Heat transfer through a representative unit cell of the secondary heat transfer structure and the sorptive material was investigated by numerical simulation in the ’039 Climeworks publication. A representative unit cell composed of a heat transfer structure concentric with the sorbent cell was investigated as shown in Figure 17 of the ’039 Climeworks publication. Temperature boundary conditions were applied by a thermal resistance representing the connection between the primary heat transfer structure and the secondary heat transfer structure at one end of the heat transfer structure separated from the unit cell. Various effects of heat connections, materials, and geometries were investigated. Among common engineering materials, aluminum was determined to be the most suitable for the selected parameters due to its high thermal conductivity, low density, and corrosion resistance. For a desired sorptive material and a desired duration of the desorption process, a cell with a length of 50 mm and an adsorbent cell diameter of 10 mm was found to be sufficiently heated by a secondary heat transfer structure with a diameter of 1.7 mm. In such a geometry, the specific gravity of the heat transfer structure becomes 0.2 kg / kg sorptive material, which is larger than the 0.06 kg / kg sorptive material described in Example 6. These structures provide high thermal conductivity in the planar direction, are easy to form, and enable effective coupling with the primary heat transfer structure.

[0197] The unit cell length of 50 mm is converted into the spacing of the primary heat transfer structure in the form of a bent aluminum tube. Thus, over the width of the frame of 1.5 m, the aluminum tube passes 10 times. This solution is a good compromise between heating density, structural stability, material requirements and the thermal mass of the frame.

[0198] The selected aluminum expanded metal of the secondary heat transfer structure is first formed around the primary heat transfer structure, increasing the contact area and conforming to the shape shown in Figure 5 of the '039 Climeworks publication. Further, the secondary heat transfer structure can be coupled to the primary structure by means of a high thermal conductivity adhesive or aluminum brazing. Shown in Figure 19 of the '039 Climeworks publication is the temperature curve of the desorption process within the frame where the expanded metal secondary heat transfer structure is soldered to the tubes of the primary heat transfer structure. In this example, a relatively low heat transfer fluid supply temperature of 93.6 °C flowed through the primary heat transfer structure. The temperature profile at the surface of the tubes and at the center of the expanded metal between the tubes shows that the sorbent reaches a temperature of 85 °C within a desorption time of 90 minutes.

[0199] Example 10. Connection to Process Equipment The stack is connected to a heat transfer fluid system. This is achieved by a heat transfer fluid distributor that engages with the primary heat transfer structure in each frame, as shown in Figure 18 of the '039 Climeworks publication. By using a heat transfer fluid distributor with a flow path cross-section larger than that of the primary heat transfer structure, the frames are set liquid-parallel, and thus the same inlet temperature and heat transfer fluid flow rate are seen, ensuring uniform heating and cooling operation. Since the heat transfer fluid distributor must engage with the free ends of the tubes of the primary heat transfer structure, the vertical position of the individual frames must be appropriately controlled. This is supported by using double-sided tape with a strict thickness tolerance for joining the frame components, as explained in Example 7 of the '039 Climeworks publication. The heat transfer fluid distributor is made of aluminum to avoid corrosion when combined with an aluminum primary heat transfer structure. The heat transfer fluid supply line of the frame inlet distributor is arranged at the lowest position, and the heat transfer fluid return line of the frame outlet distributor is arranged at the highest position. In this way, the system can be effectively purged of air.

[0200] Example 11. Heat mass of a frame using a fin and tube heat transfer structure for DAC applications The heat mass of the possible fin and tube heat transfer structures within the frame is determined for a 20 mm thick sorptive material layer. This is compared to a conventional frame structure with a 10 mm thick sorptive material layer. For reference, the mass and heat mass of a 10 mm frame with a planar expanded aluminum metal heat transfer structure according to the current design are calculated in the following table.

Table 3

[0201] The 20mm frame with the secondary heat transfer structure of the fins has a height that is doubled, so the mass of the frame C profile is doubled. The wedge spacers 23, 26 and the sealing strips 9, 8 remain the same (although the total amount in the stack is reduced). The primary heat exchanger structure maintains the same mass as the length and diameter of the tubes 11 are maintained. The main changes are seen in the secondary heat transfer structure. The results of the frame with the 20mm thick sorbent material layer and 14.1kg of sorbent material are shown in the following table.

[0202] Make the following assumptions. · Frame width = 1.5m, profile thickness 1mm · Frame length = 1.0m, profile thickness 1mm · Primary HEX volume (for 10mm sorbent layer) = 3.964e-4m 3 · Secondary HEX 100 fins, 10mm spacing, 1.5m edge, height 20mm, thickness 0.5mm, 50% of surface area perforated = 7.5e-4m 3 · Secondary HEX mass = 7.5e-4m 3 × 2700kg / m 3 = 2.025kg · Total volume of sorbent in the frame = 0.0282m 3 · Sorbent material mass = sorbent density (500kg / m 3 ) * total volume = 14.1kg

Table 4

[0203] From this example, it can be seen that with the heat transfer structure of the fins and tubes that can increase the sorbent material layer to 20mm, the heat mass per unit sorbent material of each frame is reduced by 30%. This advantage is mainly seen because the primary heat transfer structure, the wedge spacers and the sealing strips do not change according to the thickness of the sorbent material layer.

[0204] External support structure Figure 1A shows the absorbent article 101 as seen from above, incorporating a plurality of external support structures 100 arranged side by side. Each external support structure 100 encloses the absorbent material layer 5 therein to form a module (absorbent article module) mounted on the absorbent article 101. The external support structure 100 can enclose and support the particles capable of forming the absorbent material layer 5 without relying on internal support components such as the internal support frame component 7 as shown in FIG. 1, and is configured to have sufficient rigidity to define the shape and configuration of the layer 5 and maintain the integrity of the layer 5.

[0205] Figure 2A shows a plurality of external support structures 100 as seen from above of the absorbent article 101. The external support structures 100 are connected to each other via connection sites or components 200, and the separation distance of each external support structure 100 with respect to adjacent external support structures 100 can be flexibly changed.

[0206] Figure 6A shows the absorbent article 101 in which a plurality of external support structures 100 are arranged side by side rather than stacked on top of each other, as shown in FIG. 6. The connection component 200 (for example, means for attaching or fixing the external support structures 100 together) maintains the external support structures 100 in a zigzag or V-shaped configuration, and each external support structure 100 is arranged vertically to receive an air flow, as shown in FIG. 2A. Also shown is a header member 600, which can be provided such that the external support structures 100 are interconnected to the header member 600 in a supportable and sealable manner, for example, facilitating handling of the absorbent article 101 as a single unit during installation and / or replacement of the absorbent article 101 or any of its components.

[0207] FIG. 22 shows an example of a part of the external support structure 100. In this example, each external support structure has a first part 100A and a second part 100B on the opposite side of the first part 100A. Each of these parts 100A, 100B can have structures similar to each other or different from each other as will be further described below. Each part 100A, 100B includes a plurality of base parts 2200, deflection parts 2202, and an opening 2204 formed between the base part 2200 and the deflection part 2202. These parts 100A, 100B define an internal volume 2206 therebetween, and particles for forming the absorbent material layer 5 are accommodated or encapsulated in this internal volume 2206. The opening 2204 has a length L, and the base part 2200 has a length L2. L1 is defined as the distance between two adjacent base parts 2200, and L2 is defined as the distance between two adjacent openings 2204. The deflection part 2202 controls the direction of the air flow entering and exiting the internal volume 2206 as indicated by the two thick arrows.

[0208] In some examples, the lengths L1 and L2 are not the same throughout the external support structure 100 and can be different between various base parts 2200 and deflection parts 2202. For example, the deflection part 2202 can be designed to collect more air (with a larger opening and a larger deflection angle) in a location where there may be less air flow in the external support structure 100. In some examples, other variables include the size of the opening 2204, the spacing between the deflection parts 2202, the number of deflection parts 2202 formed, the deflection angle of the deflection part 2202 with respect to the base part 2200, etc., and each of these variables can be controlled to increase or decrease the air flow, change the directionality of the air flow, and / or appropriately control the inflow and outflow to the external support structure 100.

[0209] Figures 23A - 23C show different configurations of the external support structure 100, or more specifically, a single part of the support structure (100A or 100B). For example, Figure 23A shows the external support structure 100 in a "cheese grater" design. In this design, there is a continuous sheet of a rigid material such as a polymer composite, metal, or plastic (and other suitable materials as known in the art) (forming the base portion 2200), holes are opened in the surface of the sheet or base portion 2200 to form openings 2204, and a part of the sheet is permanently deformed to deflect or bulge relative to the base portion 2200, forming the deflected portion 2202.

[0210] In Figure 23B, the external support structure 100 is shown in a "louver" design, which is defined as a continuous sheet of a rigid material forming a base portion 2200 with a plurality of slits cut parallel to each other, and the portion of the base portion 2200 near the slits is permanently deformed to deflect or bulge relative to the base portion 2200, forming the deflected portion 2202.

[0211] In Figure 23C, the external support structure 100 is shown in a "fishnet" design, which is defined as a continuous sheet of a rigid material forming a base portion 2200 with a plurality of slits formed parallel to each other, and then, two opposite ends of the sheet are pulled apart by a tensile load from an external source. Due to the tension, the deflected portion 2202 buckles out of the plane that originally defined the sheet, and a plurality of openings are formed between each deflected portion 2202 and the adjacent base portion 2200 from which the deflected portion 2202 has moved in response to the tension applied to the sheet.

[0212] Figures 24A - 24D illustrate a method of assembling or forming an external support structure 100 in accordance with an example disclosed herein. Figure 24A shows an initial state of a first portion 100A that can be formed from a single continuous sheet of a rigid material as described above, after a deflection portion 2202 and an opening 2204 have been formed with respect to a base portion 2200. In Figure 24B, a layer of a porous laminate material 2400 is disposed on an inner surface of the base portion 2200 (i.e., the surface facing the internal volume 2206 when the external support structure 100 is fully assembled), covering the entire inner surface of the base portion 2200. The porous laminate material can be a flexible porous material, gas permeable, but can be impermeable to loose particulate sorbent material of the sorbent material layer 5, and is formed using any suitable porous polymer including, but not limited to, expanded polyethylene (ePE) and expanded polytetrafluoroethylene (ePTFE).

[0213] In FIG. 24C, a first portion 100A and a second portion 100B (which has undergone the same process as the first portion 100A in FIGS. 24A and 24B) are arranged relative to each other such that the porous laminate material layers 2400 of each portion face the porous laminate material layer 2400 of the other portion in a mirror image (but reversed). In the example as shown, the first portion 100A and the second portion 100B have the same structure, but it should be understood that in other examples, different structures or combinations of structures may be used for these portions. When the first portion 100A and the second portion 100B are properly aligned, the two opposing ends of these portions are joined using end caps 2402. Only two end caps 2402A and 2402B are shown, but additional end caps can be implemented as needed to create a container that defines the internal volume 2206 of the external support structure 100. The end caps 2402 are removable and, as shown in FIG. 24D, can be filled with sorbent particles that form a sorbent material layer 5 encapsulated within the end caps 2402 and the porous laminate material layer 2400. The pores of the porous laminate material layer 2400 are smaller than the size of the sorbent particles and retain such particles within the internal volume 2206, while at the same time allowing an air flow to enter through the opening 2204 of the second portion 100B of the external support structure 100 and exit through the opening 2204 of the first portion 100A (e.g., as shown in FIG. 22). The removable end caps 2402 also allow the sorbent particles of the sorbent material layer 5 to be emptied or refilled. In this configuration, there is no internal structure that would impede the process of emptying or refilling.

[0214] FIG. 25 shows the external support structure 100 as seen from above the absorbent article 101. Air flow (inflow and outflow) through the absorbent article 101 (and the individual external support structure 100) is shown, and the air flow is controlled by the angle and shape of the deflector portion 2202 as described above.

[0215] FIG. 26 shows an example of an external support structure 100 including a first portion 100A and a second portion 100B. The first portion 100A includes a plurality of base portions 2200A. The base portions 2200A are made from a single continuous sheet of material or from a plurality of discrete components attached or fixed to each other to form the first portion 100A of the external support structure 100. The first portion 100A also includes a first porous laminate material layer 2400A attached thereto. The second portion 100B includes a plurality of base portions 2200B. The base portions 2200B are made from a single continuous sheet of material or from a plurality of discrete components attached or fixed to each other to form the second portion 100B of the external support structure 100. The second portion 100B also includes a second porous laminate material layer 2400B attached thereto. The particles forming the absorbent material layer 5 can be housed between the first portion 100A and the second portion 100B within an internal volume 2206 defined by the porous laminate material layers 2400A, 2400B and the end caps 2402A, 2402B.

[0216] FIGS. 27A and 27B show examples of the external support structure 100 when the lengths of the end caps 2402A, 2402B are different. For example, in FIG. 27A, the end cap 2402A is longer in length than the end cap 2402B, and in FIG. 27B, the end cap 2402A is shorter in length than the end cap 2402B, and both define a trapezoidal cross-section of the internal volume 2206.

[0217] Figures 28A and 28B show an example of how the particles forming the sorptive material layer 5 vary depending on the region located within the internal volume 2206 of the external support structure 100. Thus, the loose particle sorptive material includes at least a first set of particles of a first size and a second set of particles of a second size smaller than the first size, and in some examples, a third set of particles smaller than the second size. Specifically, in this example, three different sizes of particles are shown, where particles 5A (first set) are the largest in size, particles 5B (second set) are smaller than particles 5A, and particles 5C (third set) are smaller than particles 5A and 5B. The particles 5A within the internal volume 2206 occupy region A, the particles 5B occupy region B, and the particles 5C occupy region C. Region A is located near the longer end cap 2402A, region C is located near the shorter end cap 2402B, and region B is located between them.

[0218] Advantageously, the different sizes of the sorptive particles allow for more flexible control of the air flow through the internal volume 2206. For example, region A containing the larger sized particles 5A can reduce the pressure change (ΔP) when the air flow passes from one side of the external support structure 100 to the other side, i.e., between the air flow (in) and the air flow (out) as shown in Figure 28B. Since the cross-sectional thickness "d1" of the sorptive material layer 5 within region A is large, the flow path within region A is also long, but due to the large particle size and low density, the flow resistance within region A can be reduced. For example, region C can contain smaller particles and increase the packing density of the particles because the cross-sectional thickness "d2" of the sorptive material layer 5 is the thinnest. Thus, the external support structure 100 can taper from one end (thickness d1) to the other end (thickness d2) and take a tapered configuration.

[0219] The geometric shape of the individual particles, the size of the individual particles, and the packing density of the particles can vary from region to region, but it is understood that these parameters can be controlled such that the flow characteristics through two or more regions are relatively similar. Advantageously, forming such regions with different parameters increases the freedom and flexibility in the design and properties of the sorbent material layer 5, and also makes it easier to appropriately design each component within the absorbent article 101 to minimize "dead zones" or non-uniform use of the sorbent material. Using the sorbent material homogeneously causes all sorbent particles to be decomposed evenly and consistently, making it easier to identify when to replace the absorbent article 101 without wasting sorbent material particles that are still usable when replacing the entire absorbent article 101.

[0220] Figures 29 and 30 show SEM images of the structure of the porous laminate material layer 2400 according to several examples using different materials. Nodes 3108, fibrils 3110, and pores, openings, or intervals 3106 are shown, which are as further described herein. Figure 29 shows ePE as the material used for the porous laminate material layer 2400. At the bottom of Figure 29, it is labeled "1.0kV 11.0mm x15.0k SE(UL) 1 / 21 / 2013", and the distance between two consecutive lines shown in the lower right corner represents 3.00 μm. Figure 30 shows ePTFE as the material used for the porous laminate material layer 2400. In some examples, the material used for the porous laminate material layer 2400 is hydrophobic to prevent liquid water from entering the internal volume 2206. In some examples, the material is also microporous with a pore size small enough to facilitate air flow while retaining sorbent particles that form the sorbent material layer 5 within the internal volume 2206. In some examples, the material withstands repeated heating and cooling cycles and has sufficient durability (e.g., higher durability than the sorbent particles of the sorbent material layer 5), so the porous laminate material layer 2400 requires less frequent replacement.

[0221] As disclosed herein, the absorbent article 101 is more efficient than prior art designs because the module (i.e., the external support structure 100 containing a loose particulate absorbent material for gas adsorption therein) is refillable and not discarded after a single use. The replaceability and reusability of the absorbent article 101 provide a more environmentally friendly design and, in the long term, improve cost efficiency. The design freedom allows for the complete and total use of all the loose particulate absorbent material within the absorbent article 101. Further, using the current structure, thinner beds or panels of particulate absorbent material for gas adsorption can be manufactured with a thickness of less than about 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.5 mm, 0.3 mm, or any suitable range or value therebetween. Implementing a thinner absorbent material layer within the aforementioned range facilitates reducing the pressure drop across the absorbent material layer. Since there is no internal support within the external support structure 100, filling and refilling the granular absorbent material for gas adsorption inside is also made easier. Also, different sized particles can be layered inside the external support structure 100 during filling or refilling. Further, the base portion 2200, the deflecting portion 2202, and the opening portion 2204 can be adjusted or changed throughout the external support structure 100 for various purposes, not limited to, for example, reinforcing large panels, preventing entry of large objects or animals, and accommodating high or low flow regions inside the external support structure 100 through its internal volume 2206 or inside.

[0222] Figures 31A, 31B, 32A, and 32B show cross-sectional views of an absorbent material layer 3100 (e.g., used as absorbent material layer 5) that includes a first surface 3102 and a second surface 3104 through which air flow can pass.

[0223] In FIG. 31A, the absorbent material layer 3100 includes two parts, namely, a first part 3101 having a larger pore size that defines a first surface 3102, and a second part 3103 having a smaller pore size that defines a second surface 3104. The two parts are adjacent to each other, and the second surface 3104 is more sealed relative to the more open first surface 3102. Each surface has a plurality of pores, openings or gaps 3106 through which foreign particles 3112 of a specific size can enter (as indicated by the white arrows), but passage to the other surface is prevented. For example, the particles that are prevented from passing through the layer can have dimensions greater than about 10 μm, greater than about 20 μm, greater than about 30 μm, greater than about 40 μm, greater than about 50 μm, or any suitable range or value therebetween.

[0224] For example, in FIG. 31A, the shape and size of the pores 3106 in each of the different parts 3101 and 3103 can be defined by a plurality of nodes 3108 and fibrils 3110 that can connect two or more nodes to each other. Thereby, the nodes 3108 and fibrils 3110 prevent foreign particles 3112 larger than a specific size from passing through the layer 3100. For example, foreign particles 3112 entering the first part 3101 are prevented from entering the second part 3103, thereby potentially preventing them from passing through the absorbent material layer 3100. The foreign particles 3112 can be trapped within the pores 3106 of the first part 3101 or released to the external environment through the first surface 3102 into which the foreign particles 3112 have entered. The nodes 3108 and fibrils 3110 can be included within a frame or an external support structure 100 (not shown).

[0225] The nodes and fibrils referred to in this specification are part of a non-woven microporous material having interconnected nodes and fibrils, and these nodes and fibrils work together to prevent foreign particles of a specific size from passing through layer 3100 while allowing air flow to pass through. By preventing the passage of such particles, not only is the purity of the contained particles maintained, but also sorptive particles are prevented from exiting the packaging layer, foreign particles are prevented from entering the package from the layer, and the purity is maintained even if the structure is bent and moved.

[0226] For example, in FIG. 31B, the sorptive material layer 3100 can be provided with an additional portion, a third portion 3105, having a pore size smaller than that of the first portion 3101, whereby the first portion 3101 can be sandwiched between two portions (3103 and 3105) having a pore size smaller than that of the first portion 3101. The third portion 3105 also has pores, openings or intervals 3106, as well as nodes 3108 and fibrils 3110. In such a configuration, since the first surface 3102 is defined by the third portion 3105 and the second surface 3104 is defined by the second portion 3103, foreign particles 3112 that may have entered the sorptive material layer 3100 from one side are captured and / or fixed within the pores 3106 of the first portion 3101, preventing passage to the other surface.

[0227] In some examples, the particles captured within the pores 3106 of the first portion 3101 can be sorptive particles, as described above, to maintain the purity of the contained sorptive particles. The sorptive particles are supplied into the pores 3106 of the first portion 3101, and then the second portion 3103 and the third portion 3105 are subsequently formed on two opposing surfaces, within which the particles are captured. The sorptive particles are provided in the form of dry particles, entrained in a forced flow (e.g., in the direction indicated by the white arrow in FIG. 31A), introduced from the more open first surface 3102, and then captured by the more sealed second surface 3104 and confined between the nodes and fibrils of the first portion 3101 of the sorptive material layer 3100, whereby the sorptive material is retained within the pores 3106 of the first portion 3101.

[0228] For example, in FIGS. 32A and 32B, the shape and size of the pores 3106 can be defined by a plurality of individual particles 3200 of the sorptive material. The sorptive particles 3200 can be included within a frame or external support structure 100 to maintain a packed bed. Here, the particles 3200 are densely packed such that while air flow can still pass through, foreign particles (not shown) are prevented from passing through the layer 3100. The frame 100 is compressible and can form a more compressed packed bed as shown in FIG. 32B as compared to a less compressed (or more expanded) packed bed as shown in FIG. 32A. The more compressed or densified packed bed results in a lower porosity (defining the pores 3106 therein) and potentially lower gas accessibility than a less compressed or densified (or more expanded) packed bed. Porosity is the relative ratio of the volume of void space in a region to the total volume of that region. As a result, in FIG. 32B, the diffusion distance is shorter compared to FIG. 32A, so the initial reaction rate of the gas adsorbed by the sorptive material layer 3100 may be faster, but the equilibrium time for CO2 adsorption in the sorptive material layer 3100 of FIG. 32B increases compared to FIG. 32A.

[0229] FIG. 33 is a SEM image of a woven fabric with openings formed between each “thread” of the fabric. Due to the size of such openings, foreign particles can enter through the fabric and internal particles can exit the fabric through these openings. FIG. 34 is a SEM image of a cross-section of a microporous material of a non-woven fabric (compared to the top view shown in FIG. 30), and for example, the material forming the sorptive material layer 3100 shown in FIGS. 31A and 31B shows nodes 3108, fibrils 3110, and pores, openings, or gaps 3106 formed therebetween. At the bottom of both FIGS. 30 and 34, it is indicated as “5.0 kv 13.3 μ”. In some examples, the fabric of FIG. 33 and the non-woven fabric material of FIG. 34 can have the same or similar air flow rates, ΔP measurements, and / or porosity measurements. The flow through the fabric can be due to large through-hole features, and the flow through the non-woven fabric material can be due to a number of small but interconnected void features (e.g., internal pores, openings, or gaps).

[0230] FIG. 35 is a SEM image of the upper surface of microporous material particles such as the particles 3200 forming the sorptive material layer 3100 shown in FIGS. 32A and 32B. The particles can have different variable sizes and shapes or configurations. Some particles may be larger or smaller than other particles, and some particles may be more rounded or less rounded than other particles. At the bottom of the image, it is indicated as "2.9 kV 10.8 mm × 200 LM(UL) 6 / 25 / 2020". The distance between two consecutive white lines shown in the lower right corner represents 200 μm. FIG. 36 is another SEM image of the top view of the microporous material particles shown in FIG. 35, but at a higher magnification. The distance between two consecutive white lines shown in the lower right corner represents 20 μm. At the bottom of the image, it is indicated as "2.0 kV 10.8 mm x2.50 k LA80(UL) 2020 / 6 / 25".

Explanation of Signs

[0231] List of Reference Signs 1 Inlet gas flow, gas inflow, main gas inflow direction 2 Outlet gas flow, gas outflow, main gas outflow direction 3 Gas inlet channel 4 Gas outlet channel 5 Granular sorptive material layer 6 Sheet of fabric material surrounding the sorptive material 7 Part of the frame that defines the geometric structure of the sorptive material layer and supports the fabric material surrounding the sorptive material 8 Structure that blocks the end of the gas inlet channel 9 Structure that blocks the start of the gas outlet channel 10 Secondary heat transfer structure within the sorptive material layer 11 Tube containing a heat transfer fluid that is part of the primary heat transfer structure within the sorptive material layer 12 Z-profile that is part of the frame defining the geometric structure of the sorptive material layer 13 Path of the bypass gas flow along the edge of the packed bed of the sorptive material within the sorptive material layer 14 Container surrounding the stack of layers of the sorptive material 15 Gas outlet manifold 16 Valve / cover for opening and closing the outlet manifold to the environment 17 C-profile which is part of the frame defining the geometry of the sorbent layer 18 Inlet surface 19 Outlet surface 20 Heat transfer structure in the thermal model 21 Sorbent material in the thermal model 22 Contact thermal resistance in the thermal model 23 Wedge-shaped spacer at the edge 24 Mounting screw 25 Mounting and orientation screw 26 Wedge-shaped spacer on 27 Heat transfer fluid distributor 28 Heat transfer fluid return line 100 External support structure 200 Flexible connection site or component 2200 Base part 2202 Deflection part 2204 Opening 2206 Internal volume 2400 Porous laminate material layer 2402 End cap 3100 Sorbent material layer 3101 First part 3102 First surface 3103 Second part 3104 Second surface 3105 Third part 3106 Pores or openings 3108 Node 3110 Fibre 3112 Foreign particles 3200 Sorbent particles d Distance between 18 and 19 d1 Thicker cross-section of the sorbent material layer d2 Thinner cross-section of the sorbent material layer Tb Temperature boundary of the thermal model L Distance between fin groups

Claims

1. A gas separation unit for separating a first gas from a mixture comprising the first gas and at least one additional gas different from the first gas, using a cyclic adsorption / desorption process that uses a loose granular sorbent material for gas adsorption, wherein the granular sorbent material is disposed within at least two stacked layers, each layer comprising two sheets of a flexible porous material that is gas permeable but impermeable to the loose granular sorbent material, the loose granular sorbent material being (1) disposed within the internal volume of an external support structure and supported by the external support structure, the external support structure including a plurality of base portions, deflecting portions, and openings therebetween, (2) disposed essentially in parallel, defining an inlet face and an outlet face of the layer, (3) disposed with the distance between the sheets in the range of 0.1 to 2.5 cm, (4) surrounding a cavity in which the granular sorbent material is disposed, the unit having a gas inlet side or gas inlet manifold through which an inflow of the gas mixture enters the unit and a gas outlet side or gas outlet manifold through which an outflow of gas exits the unit, the gas path between the inflow and the outflow being confined within the unit to pass through at least one layer, the directionality of the inflow and outflow through the external support structure being controlled by the deflecting portions of the external support structure, the layer being disposed within the unit such that the inflow passes through the inlet face, then through the granular sorbent material located within the cavity of each layer, and then out of each layer through the outlet face to form a gas outflow, the layers being arranged such that the inlet faces of adjacent layers face each other to surround a gas inlet channel and the outlet faces face each other to surround a gas outlet channel, the average distance between the inlet face and / or the outlet face defining the channel being in the range of 0.5 to 5 cm as measured in a direction essentially perpendicular to the main gas inflow direction and the main gas outflow direction, respectively, the length of each of the inlet face and / or the outlet face in the direction parallel to the main gas inflow direction and the main gas outflow direction being at least 10 times greater than the distance (d) between the sheets within the layer, and a gas separation unit, wherein at least one layer, or a majority of the layers, or all of the layers are provided with a primary heat exchange element in the form of a tube containing a heat exchange fluid, in combination with a secondary heat exchange element for enhancing heat transfer between the sorbent material and the heat exchange element.

2. The unit according to claim 1, wherein the base portion and the deflecting portion of the external support structure are formed from a continuous sheet of rigid material.

3. The unit according to claim 2, wherein the external support structure forms a cheese lattice, a louver or a fishnet structure.

4. The unit according to claim 1, wherein the plurality of base portions are separate components attached or fixed to each other.

5. The unit according to any one of claims 1 to 4, wherein the loose granular sorptive material comprises at least a first set of particles having a first size and a second set of particles having a second size smaller than the first size.

6. The unit according to claim 5, wherein the first set occupies a first region within the internal volume and the second set occupies a second region within the internal volume different from the first region.

7. The unit according to claim 5 or 6, wherein the external support structure has a tapered configuration.

8. The unit according to any one of claims 1 to 7, wherein the external support structure includes at least one end cap through which the loose granular sorptive material is provided to fill the support structure.

9. The unit according to any one of claims 1 to 8, wherein the length of the inlet face and / or the outlet face in a direction parallel to the main gas inflow direction and the main gas outflow direction respectively is at least 40 times greater than the distance (d) between the sheets within the layer.

10. The unit according to any one of claims 1 to 9, wherein the flexible porous material comprises a hydrophobic material.

11. The unit according to claim 1, wherein more than 5 layers are stacked essentially parallel to each other within the unit or stacked at a relative inclination angle in the range of 0.2 to 15°, and the corresponding inlet channels converge in the main gas inflow direction and the corresponding outlet channels diverge in the main gas outflow direction.

12. The unit according to claim 1, wherein the layers are stacked in an essentially planar structure essentially parallel to each other, or the layers are arranged concentrically with each other in an essentially cylindrical structure.

13. The unit according to claim 1, wherein spacers are arranged within the layer.

14. The unit according to claim 1, wherein the primary heat exchange element or the secondary heat exchange element also functions as a frame structure that supports a sheet of flexible porous material.

15. The unit according to claim 1, wherein the additional secondary heat exchange element is provided based on an expansion material.

16. The unit according to claim 1, wherein the loose granular sorbent material is an amine-modified granular material.

17. The unit according to claim 1, wherein the external support structure is provided with holes filled with the loose granular sorbent material, and the openings of the holes are closed after filling the sorbent material.

18. The unit according to claim 1, including an airtight surrounding cage except for the gas inlet opening for inflow and the gas outlet opening for outflow.

19. The sheets of each layer are arranged with the distance between the sheets in the range of 0.5 to 1.5 cm, or the average distance between adjacent inlet surfaces or outlet surfaces is in the range of 0.5 to 1.5 cm as measured in a direction essentially parallel to the main gas inflow direction and the main gas outflow direction respectively, of the unit according to claim 1.

20. The unit according to claim 1, wherein at least one length of the inlet surface or the outlet surface in a direction parallel to the main gas inflow direction and the main gas outflow direction respectively is at least 80 times greater than the distance (d) between the sheets in the layer.

21. The unit according to claim 1, wherein the flexible porous material is a flexible fabric material of a woven or non-woven fabric based on polymer fibers or yarns, including those based on at least one of ePTFE, ePE, PET or PE.

22. More than 20 layers are stacked essentially parallel to each other within the unit using a stack of corresponding external support structures, or stacked at a relative inclination angle in the range of 0.5 to 10°, with the corresponding inlet channels converging in the main gas inflow direction and the corresponding outlet channels spreading in the main gas outflow direction, either of which the inlet channels are closed at the downstream end by the contact of the side edges of adjacent layers, the outlet channels are closed at the upstream end by the side edges of adjacent layers, of the unit according to claim 1.

23. The unit according to claim 1, wherein the spacer is arranged within the layer, and the spacer is a rigid bar or rail structure including a T, H, C or Z-bar structure, or is provided by a joint or seam between the sheets.

24. The unit according to claim 1, wherein the primary heat exchange element or the secondary heat exchange element also functions as a frame structure that supports a sheet of flexible porous material.

25. The unit according to claim 1, wherein the secondary heat exchange element is based on expanded metal including corrugated expanded metal.

26. The unit according to claim 1, wherein the loose granular sorptive material is an amine-modified granular material based on amine-modified nanofibrillated cellulose having an average particle diameter in the range of 60 to 1200 μm for adsorbing carbon dioxide.

27. Including an enclosure cage made of a flexible or rigid material, the enclosure cage being airtight except for a gas inlet opening for inflow and a gas outlet opening for outflow, attached to a vacuum unit for the desorption process, and a controllable lid or valve for switching between the adsorption stage and the desorption stage being provided at the inlet opening and / or the outlet opening. The unit according to claim 1.

28. The unit according to claim 1, wherein the loose granular sorptive material is arranged in a range where the distance between the sheets is 0.1 to 0.5 cm.

29. A method for extracting carbon dioxide from air or flue gas in a cyclic adsorption / desorption process using a loose granular sorptive material for gas adsorption, adsorbing carbon dioxide or carbon dioxide and water vapor using the unit according to claim 1, wherein the adsorption is carried out in a temperature range of -30 to 40 °C and an absolute pressure of 0.7 to 1.3 bar, and, After adsorbing carbon dioxide or carbon dioxide and water vapor, heat the sorbent material to 50 to 120 °C, and reduce the absolute pressure to lower the partial pressure of CO ２ around the sorbent material, and / or expose the sorbent material to a purge gas stream to desorb the sorbent material. A method including.

30. A gas separation unit for separating a first gas from a mixture containing the first gas and at least one additional gas different from the first gas using a cyclic adsorption / desorption process using a loose granular sorptive material for gas adsorption, wherein the granular sorptive material is arranged in at least two stacked layers, each layer includes two sheets of flexible porous material that are gas permeable but impermeable to the loose granular sorptive material, and the loose granular sorptive material is (1) arranged within the internal volume of an external support structure, supported by the external support structure, the external support structure including a plurality of base portions, deflection portions, and openings therebetween, (2) arranged essentially parallel, defining an inlet face and an outlet face of the layer, (3) arranged in a range where the distance between the sheets is 0.1 to 2.5 cm, (4) surrounding a cavity in which the granular sorptive material is arranged. The unit has a gas inlet side or gas inlet manifold through which an inflow of the gas mixture enters the unit, and a gas outlet side or gas outlet manifold through which a gas outflow exits the unit, and a gas path between the inflow and the outflow is confined within the unit to pass through at least one layer, and the directionality of the inflow and outflow through the external support structure is controlled by the deflecting portion of the external support structure. The layer is arranged within the unit such that the inflow passes through the inlet face, then through a granular sorptive material located within the cavities of each layer, and then exits each layer through the outlet face to form a gas outflow. The layers are arranged such that the inlet faces of adjacent layers face each other to surround a gas inlet channel, and the outlet faces face each other to surround a gas outlet channel. The average distance between the inlet face and / or the outlet face defining the channel, measured in a direction essentially perpendicular to the main gas inflow direction and the main gas outflow direction respectively, is in the range of 0.5 to 5 cm. The length of each of the inlet face and / or the outlet face in a direction parallel to the main gas inflow direction and the main gas outflow direction is at least 10 times greater than the distance (d) between the sheets within the layer, and Each layer is provided with a tube and a stackable backbone element is provided. Means for fluid transfer attachment of the ends of the tubes are provided within or to the stackable backbone element, and The stackable backbone element is a gas separation unit that can be connected to each other to transfer heat transfer fluid to and from the tubes within individual layers.

31. A gas separation unit for separating a first gas from a mixture containing the first gas and at least one additional gas different from the first gas, using a cyclic adsorption / desorption process using a loose granular sorptive material for gas adsorption, wherein the granular sorptive material is arranged within at least two stacked layers. Each layer is gas permeable but includes two sheets of a flexible porous material that is impermeable to the loose granular sorbent material. The loose granular sorbent material is disposed within the internal volume of an external support structure and is supported by the external support structure. The external support structure, which includes a plurality of base portions, deflecting portions, and openings therebetween, is disposed essentially parallel to define an inlet face and an outlet face of the layer. The distance between the sheets is in the range of 0.1 to 2.5 cm and encloses a cavity in which the granular sorbent material is disposed. The unit has a gas inlet side or gas inlet manifold through which an inflow of a gas mixture enters the unit and a gas outlet side or gas outlet manifold through which a gas outflow exits the unit. The gas path between the inflow and the outflow is confined within the unit to pass through at least one layer. The directionality of the inflow and outflow through the external support structure is controlled by the deflecting portions of the external support structure. The layer is disposed within the unit such that the inflow passes through the inlet face, then through the granular sorbent material located within the cavity of each layer, and then exits each layer through the outlet face to form a gas outflow. The layers are arranged such that the inlet faces of adjacent layers face each other to enclose a gas inlet channel and the outlet faces face each other to enclose a gas outlet channel. The average distance between the inlet face and / or the outlet face that defines the channel is in the range of 0.5 to 5 cm, measured in a direction essentially perpendicular to the main gas inflow direction and the main gas outflow direction, respectively. The length of each of the inlet face and / or the outlet face in a direction parallel to the main gas inflow direction and the main gas outflow direction is at least 10 times greater than the distance (d) between the sheets within the layer. And Tubes are provided in each layer, and stackable backbone elements are provided within or as part of the external support structure. Means for fluid transfer attachment of the ends of the tubes are provided within or to the stackable backbone elements. The stackable backbone elements are connected to each other directly or via additional tubes including the use of O-rings and can be connected to transfer heat transfer fluid to and from the tubes within individual layers. The stackable backbone elements are cylindrical elements with diameters in the range of 1 to 5 cm, and the tubes of the primary heat exchange structure and the secondary heat exchange structure can be directly included within the external support structure during an injection molding process, a gas separation unit.

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