Sorption cell and system for separating a gas and / or atmospheric moisture from ambient air, and method for producing a sorption cell
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- VOLKSWAGEN AG
- Filing Date
- 2024-08-13
- Publication Date
- 2026-06-24
Smart Images
Figure EP2024072833_20022025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Sorption cell and system for separating a gas and / or humidity from ambient air and method for producing a sorption cell
[0003] The invention relates to a sorption cell for a system for separating a gas and / or humidity from the ambient air, a system for separating a gas and / or humidity from the ambient air and a method for producing a sorption cell according to the preamble of the independent patent claims.
[0004] To reduce carbon dioxide emissions in the ambient air and achieve climate neutrality, not only must carbon dioxide emissions be reduced, but unavoidable carbon dioxide emissions must also be compensated accordingly. One option for compensating these carbon dioxide emissions is to capture carbon dioxide from the ambient air. This process is also known as a direct air capture process and is suitable for reducing the proportion of carbon dioxide in the atmosphere. Alternatively or additionally, carbon dioxide emissions can be compensated by permanently storing carbon dioxide in a reservoir, particularly in a rock layer, thus preventing it from entering the atmosphere.
[0005] Systems and methods for capturing carbon dioxide from ambient air are known from the prior art. Such capture can be carried out using the so-called "direct air capture" process, whereby the carbon dioxide can be captured directly from the ambient air, stored, or fed into a further process. Most known methods for capturing carbon dioxide from ambient air employ a cyclic process using a combination of pressure and / or temperature changes. In a first process step, the carbon dioxide present in the atmospheric air is bound in a sorption element. The carbon dioxide bound in the sorption element can be released again in a second process step.The development of suitable adsorption materials and their technical implementation in appropriate adsorption systems aims to enable efficient and energetically effective carbon dioxide capture. One challenge is the development of efficient adsorption systems in which the sorption elements are technically arranged and / or designed in such a way that, on the one hand, the adsorption and desorption of carbon dioxide proceeds optimally and, on the other hand, a comparatively cost-effective system concept can be implemented. In particular, the heating and cooling phases influence the process costs, while the design of the sorption element and the process chamber influence the system costs. A further disadvantage of the known solutions is that the sorbent materials used, especially physisorbents, are sensitive to moisture.This means that the sorbent is capable of absorbing even the residual moisture from the dried air into the porous microstructure, which directly reduces the absorption capacity for carbon dioxide from the ambient air. In practical terms, this would mean that the process becomes less efficient, resulting in a much lower carbon dioxide yield for the same energy consumption in the capture process. This fact means that sorbent regeneration would have to be introduced into the process to remove the moisture from the sorbent. This would further worsen the energy balance of the process. According to the current state of the art, the sorbent material is primarily heated to the desired temperature using heat exchangers.The conventionally known sorbent materials have very poor thermal conductivity, which has a negative impact on the overall energy costs, especially during desorption.
[0006] EP 3 151 947 B1 discloses a vacuum chamber for a direct air capture process, which encloses an interior space for accommodating an adsorber structure. The interior space is defined by a wall in which at least one inlet cover and one outlet cover are arranged. In an open position, the covers allow gas to circulate through the vacuum chamber to contact the adsorber structure. In a closed position, the covers seal the vacuum chamber, allowing the interior of the vacuum chamber to be evacuated.
[0007] EP 3 166 708 B1 discloses a method and device for the regeneration of materials that can achieve both a high cyclic yield in cyclic adsorption and desorption processes and a high purity of the desorbed gas during gas separation. The underlying principle is the combination of temperature-vacuum swing adsorption-desorption cycles, which are known to produce a desorption gas of high purity, with the addition of steam as a purge gas, which is known to support desorption processes and enable a high cyclic yield with short process times. A process chamber is evacuated to a pressure of 20–400 mbar, and the sorption material is preheated to a temperature of 35–80°C.To support the desorption of carbon dioxide, water vapor is introduced into the process chamber, which expels the carbon dioxide from the sorption material and thus supports the yield of carbon dioxide at comparatively low process temperatures in a comparatively energy-efficient process.
[0008] Furthermore, WO 2007 / 054255 A1 discloses a process for producing a sorbent-containing coating on a substrate, using an adhesion-promoting component in liquid or dissolved form. The coating is applied to the substrate at a temperature between 100°C and 500°C and at a pressure lower than ambient pressure.
[0009] The invention is based on the object of improving the energy efficiency of a plant for separating carbon dioxide from the ambient air and at least partially overcoming the disadvantages known from the prior art.
[0010] This object is achieved by a sorption cell according to the invention for a system for separating a gas to be adsorbed and / or humidity from the ambient air. The sorption cell comprises a support made of an electrically conductive material and a sorbent material for absorbing the gas to be adsorbed and / or the humidity from the ambient air, which encloses the support. The sorption cell further comprises an electric heating element for heating the sorbent material to a desorption temperature or a regeneration temperature.
[0011] In this context, a carrier is understood to mean any configuration designed to be encased in a material. This includes, in particular but not exclusively, meshes, sieves, grids, spirals, and similar geometric shapes in which a corresponding distance is formed between one structural element and another structural element of the carrier or between a first section of the structural element and a second section of the structural element, so that the structural elements or the sections of the structural element can be correspondingly encased with the sorbent material.
[0012] In this context, a sorbent material is understood to be a material which is suitable for reversibly binding a gas to be adsorbed, in particular carbon dioxide, through chemical or physical processes and subsequently releasing it again or drying an air stream of ambient air.
[0013] In this context, a desorption temperature is the temperature at which the carbon dioxide chemically or physically bound in the sorbent material is released. A regeneration temperature is the temperature at which the sorbent material returns to its original state, particularly at which the humidity bound in the sorbent material is released.
[0014] The sorption cell according to the invention enables particularly energy-efficient heating of the sorbent material, since it does not heat an entire bed of spheres, but rather the sorbent material is in direct contact with the easily heatable support. This reduces the number of heat transfers, thereby reducing losses and increasing energy efficiency.
[0015] The additional features listed in the dependent claims enable advantageous further developments and improvements of the sorption cell specified in the independent claim.
[0016] In an advantageous embodiment of the sorption cell, the support is coated with the sorbent material or wrapped with the sorbent material. This enables particularly efficient heat transfer from the electrically conductive support, in particular a metallic support, to the sorbent material. Furthermore, a coating can achieve a correspondingly large surface area with minimal material usage, thus reducing the required sorbent material. This is particularly advantageous for expensive sorbent materials.
[0017] In a particularly advantageous embodiment of the sorption cell, the heating element is integrated into the carrier. This allows for a particularly compact design of the sorption cell. In particular, the carrier itself can form the electrical heating element by supplying current to the carrier via a corresponding connection, and heating up due to the electrical resistance as the medium flows through the carrier.
[0018] According to an advantageous embodiment of the sorption cell, the electrical heating element is designed as a heating coil. A heating coil is a particularly simple embodiment of a heating element, which can be formed from only a single structural element with a corresponding electrical connection. The coil windings can be easily and cost-effectively coated with the sorbent material.
[0019] In a further advantageous embodiment of the sorption cell, the electric heating element is designed as a heating mat or a heating fabric. A heating mat or a heating fabric are further options for creating an efficient and cost-effective heating element that can be easily coated with a sorbent material.
[0020] According to an advantageous embodiment of the invention, the heating element comprises a wire mesh composed of warp and weft threads, with either the warp or weft threads, or both the warp and weft threads, being designed as heating wires. Configuring the heating element as a wire mesh with warp and weft threads enables simple and cost-effective production of the heating element.
[0021] Warp and weft threads also include, in particular, warp wires and weft wires, as used to manufacture such a wire mesh. The wire mesh allows for the mesh size of the heating element to be adjusted easily and reproducibly. The use of different warp and weft threads also provides an additional degree of design flexibility, which can improve the efficiency of heating and / or carbon dioxide sorption.
[0022] In an advantageous embodiment of the invention, the heating element comprises a wire mesh composed of heating wires and wires, tapes, or threads other than the heating wires. The individual wires can be ideally designed for their respective tasks. Thus, the heating wires can be optimized for the best possible temperature transfer, while the other wires, tapes, or threads can be optimized with regard to thermal conductivity and adhesion properties for coating with the sorbent material. Furthermore, the wires, tapes, or threads other than the heating wire can also form the sorbent material or support the sorbent material.
[0023] According to an advantageous embodiment of the heating element, the heating wires are connected to one another via a busbar. This enables a simple and cost-effective power supply for all of the heating wires of the heating element. The busbar can be made of copper in particular, since copper not only conducts electrical current but also has high thermal conductivity. In an advantageous embodiment of the sorption cell, the carrier has a connection for a power supply. This enables particularly simple electrical contact with the carrier, so that the carrier can be heated in a particularly energy-efficient manner. In addition, such a power connection facilitates the installation of the sorption cell in a process chamber of a system for separating carbon dioxide from the ambient air.
[0024] In a further advantageous embodiment of the invention, a peripheral surface of the sorption cell is molded with sorbent material in a uniform and essentially flawless manner. During the manufacture and assembly of the sorption cell, care must be taken to ensure that the peripheral surface electrically insulates the heating element to prevent short circuits and simultaneously achieves a seal against a system wall. Essentially flawless means that the peripheral surface has no breakouts, notches, or depressions beyond the manufacturing-related roughness.
[0025] In a preferred embodiment of the sorption cell, the carrier is designed as a fine wire mesh, with openings formed between the individual wires of the fine wire mesh, through which openings a gas stream is conducted to separate the carbon dioxide present in this gas stream. The design of the carrier offers a correspondingly wide range of structural design options. For example, the diameter of the wire, the surface quality, the mesh size, the material selection and the manufacturing process for producing the carrier can be varied in order to find an optimal combination for the application. The size of the openings is essentially determined by the mesh size of the fine wire mesh. The diameter of the openings is advantageously in the range from 0.1 mm to 5 mm, preferably in the range from 0.2 mm to 3 mm, particularly preferably in the range from 0.25 mm to 2 mm.
[0026] In an advantageous embodiment, these openings are distributed substantially evenly over the surface of the sorption cell. This allows for a particularly favorable flow through the sorption cell, resulting in maximum absorption of carbon dioxide by the sorbent material.
[0027] According to a particularly preferred embodiment of the sorption cell, the sorbent material is a physisorbent, in particular a zeolite. Physisorbents are particularly efficient at absorbing carbon dioxide from a dry air stream with a residual humidity of less than 5%. At higher air humidity, additional humidity is absorbed by the sorbent material, thereby reducing the carbon dioxide absorption capacity.
[0028] In an alternative design of the sorption cell, the sorbent material can also be a chemisorbent. Chemisorbents are also suitable for adsorbing carbon dioxide from the ambient air and subsequently releasing it in a desorption process.
[0029] A further aspect of the invention relates to a system for separating a gas to be adsorbed and / or humidity from the ambient air. The system comprises a flow generator, in particular a fan, for conveying the ambient air through the system. The system further comprises a first process chamber for drying the ambient air and a second process chamber downstream of the first process chamber in the flow direction of a gas stream through the system for separating the gas to be adsorbed, in particular carbon dioxide, from the ambient air dried in the first process chamber. At least one of the two process chambers, in particular the second process chamber, contains one or preferably several sorption cells described in the preceding sections.
[0030] The system according to the invention enables particularly efficient separation of the gas to be adsorbed, in particular carbon dioxide, from the ambient air. The design of the sorption cells in the first process chamber allows for particularly efficient drying of the ambient air. The described design of the sorption cells in the second process chamber enables particularly energy-efficient desorption of the gas to be adsorbed, in particular carbon dioxide, from the sorbent material, thereby achieving a high yield of carbon dioxide with relatively low energy consumption and minimizing waste heat losses.
[0031] In an advantageous embodiment of the system, a sorption element comprising a plurality of heatable sorption cells is arranged in one of the process chambers. The sorption cells are arranged in at least two different cascades in the flow direction of a gas stream through the process chamber. Furthermore, the sorption element has at least two heating elements, with at least one heating element assigned to each cascade. Ambient air flows through the cascades in series, such that the waste heat from the sorption cells of the first cascade is transferred to the sorption cells of the second cascade.
[0032] Such a system enables particularly efficient drying of the ambient air and subsequent efficient adsorption of carbon dioxide or another gas to be separated from the ambient air.
[0033] A further aspect of the invention relates to a method for producing a sorption cell for a system for separating carbon dioxide from ambient air. The method comprises at least the following steps:
[0034] Providing a carrier made of an electrically conductive material,
[0035] Providing a sorbent material for absorbing carbon dioxide from the
[0036] ambient air,
[0037] Providing an electric heating element,
[0038] Coating the carrier with the sorbent material, and
[0039] - Arranging the electric heating element in such a way that the carrier coated with the sorbent material can be heated by the electric heating element.
[0040] Such a process enables the production of a sorption cell according to the invention in a simple and cost-effective manner.
[0041] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.
[0042] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show:
[0043] Figure 1 shows a state-of-the-art system for separating
[0044] Carbon dioxide from the ambient air,
[0045] Figure 2 shows a prior art adsorption chamber for such a
[0046] Attachment,
[0047] Figure 3 shows a plant according to the invention for separating carbon dioxide from the
[0048] Ambient air in a schematic representation, Figure 4 shows a preferred embodiment of a sorption cell of a plant according to the invention for separating carbon dioxide from the ambient air,
[0049] Figure 5 shows a further preferred embodiment of a sorption cell for a
[0050] Plant for the separation of carbon dioxide from the ambient air,
[0051] Figure 6 shows a further preferred embodiment of a sorption cell for a
[0052] Plant for the separation of carbon dioxide from the ambient air,
[0053] Figure 7 shows a preferred embodiment of a system according to the invention for
[0054] Separation of carbon dioxide from the ambient air in a schematic representation,
[0055] Figure 8 shows a further preferred embodiment of an inventive
[0056] Plant for the separation of carbon dioxide from the ambient air,
[0057] Figure 9 is a schematic representation of a process room with several
[0058] Cascades of sorption cells for a plant according to the invention for separating carbon dioxide from the ambient air,
[0059] Figure 10 shows a heating element in the form of a heating coil for a system according to the invention for separating carbon dioxide from the ambient air,
[0060] Figure 11 shows a collection of possible heating elements in the form of heating mats, which can be used to construct a sorption cell for a process room,
[0061] Figure 12 shows a preferred variant of a heatable carrier with a carrier material with a coating of a sorbent material,
[0062] Figure 13 shows a further preferred variant of a heatable carrier with a carrier material with a coating of a sorbent material, and
[0063] Figure 14 shows a flow diagram for producing a sorption cell according to the invention. Figure 1 shows a simplified schematic representation of a system 10 known from the prior art for separating carbon dioxide 70 from the ambient air 11. The system 10 comprises a process chamber 12 in which an adsorption chamber 14 for adsorbing carbon dioxide 70 is arranged. The adsorption chamber 14 comprises at least one sorption element 16 with a spherical sorbent material 18, which is preferably designed as a chemisorbent. The sorbent material 18 chemically binds carbon dioxide 70 from the ambient air 11 and thus removes the carbon dioxide 70 from the ambient air 11. Amine-functionalized, porous materials are particularly suitable as the sorbent material 18. The sorbent material 18 is stored in the adsorption chamber 14 as a fixed bed.For this purpose, a support frame 20 is provided for receiving the sorbent material 18, into which the sorbent material 18 is introduced. The adsorption chamber 14 arranged in the process chamber 12 can be heated and cooled by a temperature control unit, in particular by a heat exchanger 22. The process chamber 12 has an inlet through which the ambient air 11 can flow into the process chamber 12 and which can be closed by a corresponding flap, hatch, or door. The system 10 further comprises a flow generator 24, in particular a fan 26, for conveying an air flow of the ambient air 11 through the process chamber 12. A pressure reduction unit 28, in particular a vacuum pump, is also provided on the process chamber 12 to at least partially evacuate the process chamber 12 and reduce the pressure in the process chamber 12 compared to the ambient pressure.Furthermore, a first outlet is provided on the process chamber 12, which is preferably connected to the environment and enables the ambient air 11 to be discharged from the process chamber 12 into the environment. Furthermore, a second outlet is provided on the process chamber 12, via which a gas stream containing the separated carbon dioxide 70 can be discharged from the process chamber 12. The inlet and the outlets can be closed by corresponding control elements, in particular by valves, in order to seal the process chamber 12 gas-tight from the environment. The carbon dioxide 70 from the ambient air 11 is first absorbed in the adsorption chamber 14 in the sorbent material 18 in a known manner and, in a subsequent process step, is released again from the sorbent material 18 by temperature and pressure changes, optionally supported by the additional introduction of water vapor into the process chamber 12.
[0064] Figure 2 shows a schematic and simplified representation of an arrangement of adsorption chambers 14 in a process chamber 12 known from the prior art. Figure 2 shows a zigzag arrangement of several fixed beds, which accordingly support the sorbent material 18. Heat exchangers 22 are installed within the individual adsorption chambers 14 in order to heat the sorbent material 18 accordingly in the desorption process or to cool it again in a process step following the desorption process in order to precondition the sorbent material 18 for a renewed absorption of carbon dioxide 70.
[0065] The disadvantages resulting from the prior art can be seen in the system 10 shown in Figures 1 and 2. Depending on the process, the temperature control of the sorbent material 18 is energy-intensive and inefficient. The sorbent material 18 itself has low thermal conductivity and is formed from a bed of sorbent spheres. Due to the numerous heat transfers from sorbent sphere to sorbent sphere, the temperature control time is significantly extended, requiring high energy consumption and resulting in correspondingly high heat losses.
[0066] Figure 3 shows a schematic representation of a system 10 according to the invention for separating a gas to be adsorbed and / or air humidity from the ambient air 11. The system 10 is designed in particular as a system for drying an air stream of the ambient air 11 and for the subsequent separation of carbon dioxide 70 from the ambient air 11. The system 10 comprises a first process chamber 12 for dehumidifying the ambient air 11 and a second process chamber 30 for separating carbon dioxide 70 from the dried ambient air 11. The first process chamber 12 and the second process chamber 30 are fluidly connected to one another via an intermediate element 32. In the first process chamber 12, a plurality of sorption cells 100, 102, 104, 106, 108 are arranged, wherein each sorption cell 100, 102, 104, 106, 108 has a heatable carrier 36 which is encased and / or coated with a first sorbent material 18.The electrically heatable support makes it possible to introduce a defined amount of heat into the sorption cells 100, 102, 104, 106, 108 at a desired position in order to simplify the process control, in particular the drying of the ambient air. Silica gels and zeolites are particularly intended as the first sorbent material 18 for the first process chamber 12. In principle, however, any material is suitable that absorbs the moisture from the ambient air 11 and thus dries the gas stream 72 and makes it cyclically regenerable. The dried ambient air 11 is introduced into the second process chamber 30 via the intermediate element 32. A plurality of sorption cells 60, 62, 64, 66, 68 are arranged in the second process chamber 30, each having a support 36, a heating element 40, and a second sorbent material 38. Preferably, the carrier 36 is coated and / or encased with the second sorbent material 38.The second sorbent material 38 can differ from the first sorbent material 18 with regard to its chemical composition and structural design. Preferably, the second sorbent material 38 is a physisorbent, in particular a zeolite. The primary function of the second sorbent material 38 is to adsorb carbon dioxide 70 from the gas stream 72 of the dried ambient air 11. Accordingly, any material suitable for physically and / or chemically binding carbon dioxide and subsequently releasing it again in a desorption process is suitable as the second sorbent material 38. The system 10 further comprises a flow generator 24, in particular a blower 26, for conveying a gas stream 72 of the ambient air 11 through the two process chambers 12, 30.Furthermore, a pressure reduction unit 28, a pressure sensor 42, a temperature sensor 44, and a gas sensor 46 for detecting the carbon dioxide concentration are arranged at least in the second process chamber 30. Preferably, at least one pressure reduction unit 28, a pressure sensor 42, and a temperature sensor 44 are also arranged in the first process chamber 12. The system 10 further comprises a central control device 114, via which different profiles can be mapped during the drying of the ambient air 11, during the adsorption of the carbon dioxide 70, and during the desorption of the carbon dioxide 70. Compared to systems 10 known from the prior art, the system 10 according to the invention eliminates the need for complex and energy-intensive temperature control devices such as heat exchangers, allowing the system 10 to be designed in a simpler, more cost-effective, and more compact manner. The temperature of the sorbent materials 18, 38 is controlled directly by heating the supports 36.
[0067] Figure 4 shows a preferred embodiment of a sorption cell 60, 62, 64, 66, 68 according to the invention for a process chamber 12, 30 of a system 10 according to the invention for drying ambient air and subsequently separating carbon dioxide 70 from the ambient air. Preferably, the sorption cells 100, 102, 104, 106, 108 of the first process chamber 12 are constructed similarly. The description of the embodiment is a general explanation of design and function. It is assumed that any sorbent materials 18, 38 can be used for adsorption and desorption cells 60, 62, 64, 66, 68. The sorbent material 18, 38 can be a sorbent material 18 for drying the ambient air 11 or a sorbent material 38 for adsorbing carbon dioxide 70. In principle, however, the sorption cell according to the invention is also suitable for adsorbing other gases.The sorption cell 60 comprises a metallic support 36 configured as an electrical heating element 40. Due to the process, the heating element 40 has the function of heating sorbent material 18, 38 in the sorption cell 60 and thus drying the ambient air 11, assisting the desorption of carbon dioxide, and / or regenerating the sorbent material 18, 32 of the sorption cell 60.
[0068] In addition to its heating function, the metallic support 36 serves as a structural support, to which sorbent materials 18, 38 are attached on both sides. This can be achieved, in particular, by coating or encasing the support 36 with the sorbent material 18, 38. One or more supports 36 form a sorption cell 60, which is manufactured to be compact and robust in order to demonstrate full functionality in industrial use over a planned service life of at least 10 years. The sorbent material 18, 38 is a purely porous material coating on the support 36. In this exemplary embodiment, the support 36 of the sorption cell 60 is made of a metallic fine wire mesh. The finished woven and / or welded heating element 40 has corresponding connections to the power supply 122. The design of the heating element 40 depends on many factors.It is assumed that different combinations are possible with regard to the selection of wire diameter, surface quality, mesh size, material selection, and manufacturing processes. The invention is not limited to the exemplary embodiment shown in Figure 4; during the manufacture of the sorption cell 60, care must be taken to ensure that the peripheral surfaces 126 are reproduced uniformly and without defects. This involves, on the one hand, covering the heating element 40 with sorbent material 18, 38 and, on the other hand, ensuring that these peripheral surfaces 126 provide a corresponding seal with a system wall when the sorption cell 60 is installed in a process chamber 12, 30 of the system 10.
[0069] After production, the finished sorption cell 60 has a plurality of openings 124 distributed in a grid. The size of the openings 124 is determined in particular by the mesh size of the electric heating element 40. The webs of the support 36, which can also have different dimensions, are located between the openings 124. The sorbent materials 18, 38 are designed such that the entire surface of the sorption cell 60 ensures full activity during adsorption, desorption, drying, and regeneration. The distribution and shape of the openings 124 of the sorption cell 60 can be designed differently. One embodiment is shown in section AA, in which the openings 35 are distributed symmetrically. In another possible embodiment, shown in section A'-A', the supports 36 of the sorption cell 60 are arranged slightly offset.The offset of the openings 124 can enable better wetting of the surface of the sorbent material 18, 38 with the ambient air 11, which can lead to improved adsorption and desorption of carbon dioxide 70. In addition to the sorption cell designs shown in Figure 4, further embodiments are possible, so the invention is not limited to the embodiments shown in Figure 4. For this purpose, Figure 4 shows further possible final design shapes of sorption cells 60, such as a rectangular shape, a triangle or square design, or a plurality of adjacent squares.
[0070] Figure 5 shows a further preferred embodiment of a sorption cell 60 for a system 10 for separating a gas and / or humidity, in particular for separating carbon dioxide 70, from the ambient air 11. The basic structure corresponds to the structure described in Figure 4. In contrast to the embodiment in Figure 4, in this embodiment, the openings 124 are circular. The openings 124 can be designed symmetrically or asymmetrically along the entire surface of the sorption cell 60. The diameter of the openings 124 can vary in the range from 0.1 mm to 5 mm. The metallic carrier 36 can be designed as a mesh or as a specific contour, whereby a controlled current flow is provided by a power supply 122. The carrier 36 has corresponding connections for the power supply 122.As in the embodiment in Figure 4, in this embodiment, other design shapes of sorption cells 60 are also possible, such as rectangle, triangle, square, multiple squares.
[0071] Figure 6 shows a further preferred embodiment of a sorption cell 60. The structure essentially corresponds to the structure described in Figure 4. However, in the embodiment shown in Figure 6, the sorption cell 60 has no visible openings 124. Instead of visible openings 124, a sorbent material 18, 38 with a high degree of surface roughness is used here, wherein the surface is designed similarly to the surface of a rice cake. The structure of the sorbent material 18, 38 is manufactured such that a gas stream 72 of the ambient air 11 flows not only partially perpendicular to the sorption cell 60 through the process chamber 12, 30, but at least partially along the rough surface of the sorption cell 60. The flow path of the ambient air is shown in section AA in Figure 6. The flow paths through the sorption cell 60 can be designed symmetrically or asymmetrically along the entire surface.
[0072] As with other embodiments, the design of the electrically heatable support 36 can be varied. Figure 6 shows four different configurations in the form of a mesh, a meander, a meander with a return line, and a heating coil. The electrically heatable support 36 has a power connection 122 in each case.
[0073] Figure 7 shows a schematic representation of a preferred embodiment of a system 10 according to the invention for separating carbon dioxide 70 from the ambient air 11. The system 10 comprises a first process chamber 12 for separating atmospheric humidity from the ambient air 11 and a second process chamber 30, connected to the first process chamber 12 via an intermediate element 32, in particular via a connecting line, for adsorbing and subsequently desorbing carbon dioxide 70 from the gas stream 72 of the ambient air 11 dried in the first process chamber.
[0074] The first process chamber 12 has a plurality of sorption cells 100, 102, 104, 106, 108, through which fluid flows one after the other. Any material that extracts moisture from the ambient air 11 and can be periodically regenerated is suitable as the sorbent material 18 for the sorption cells 100, 102, 104, 106, 108. Preferably, the sorbent material 18 is a material known for drying, such as silica gel, zeolite A3, or the like. The first process chamber 12 is connected to the second process chamber 30 via the connecting line in such a way that semi- and fully automatic control is possible. The sorption cells 60, 62, 64, 66, 68 according to the invention described in the previous sections are installed in the second process chamber 30. The sorbent material 38 used for the second process chamber 30 is suitable for the adsorption and desorption of carbon dioxide 70.The second sorbent material 38 is preferably a physical sorbent material, in particular a zeolite. Due to their robustness, zeolites are particularly well suited as adsorbers for the capture of carbon dioxide. The sorption cells 100, 102, 104, 106, 108 of the first process chamber 12 and the sorption cells 60, 62, 64, 66, 68 of the second process chamber 30 each have an electrical connection 122, which are connected to the control device 114 for the overall system control. A fully regulated power unit 120 provides the energy for heating at the desired current and voltage level, either constant or pulsed (AC / DC). Preferably, a corresponding adjustment of voltage profiles (e.g., pulsating DC voltage, sinusoidal AC voltage, etc.) is possible in the case of pulsed control.The system 10 further comprises a pressure reduction unit 28, in particular a vacuum pump 112, which extracts the residual air from the second process chamber 30 before desorption takes place or supports the desorption itself in the second process chamber 30. Additionally, the pressure reduction unit 28, in particular the vacuum pump 112, can support the drying of the air and / or the regeneration of the sorbent material 18 in the first process chamber 18. Furthermore, the system has a carbon dioxide storage unit 110 for absorbing the carbon dioxide desorbed from the second sorbent material 38 in the second process chamber 30.
[0075] The system 10 further comprises at least one flow generator 24, in particular a blower 26, for directing a gas stream 72 of the ambient air 11 through the process chambers 12, 30. The system 10 preferably has a first flow generator 24, in particular a first blower 26, which conveys the ambient air 11 into the first process chamber 12, and a second flow generator 48, in particular a second blower 26, which conveys the dried gas stream 72 of the ambient air 11 into the second process chamber 30. Furthermore, a pressure sensor 42, a temperature sensor 44, a gas sensor 46 for detecting the air humidity, or a gas sensor 46 for detecting the concentration of carbon dioxide 70 can be arranged at the process chambers 12, 30, via which the control device 114 receives corresponding information for the overall system control.The sorption cells 100, 102, 104, 106, 108 of the first process chamber or the sorption cells 60, 62, 64, 66, 68 of the second process chamber 30 are electrically connected to the control device 114. This makes it possible to control the sorption cells 60, 62, 64, 66, 68, 100, 102, 104, 106, 108 as desired or to heat the desired sorption cell 60, 62, 64, 66, 68, 100, 102, 104, 106, 108 to the desired temperature via temperature sensors integrated into the sorption cells, via temperature control or current regulation, thus enabling optimal process control.
[0076] Detail "A" shows the sorption element 34 of the second process chamber 30. The individual sorption cells 60, 62, 64, 66, 68 are designed as described for Figures 3 to 5. Preferably, each sorption cell 60, 62, 64, 66, 68 has its own power supply 122. When designing the system 10, all construction guidelines regarding issues such as expansion, sealing, insulation, etc. are taken into account.
[0077] Figure 8 shows a further preferred embodiment of a system 10 according to the invention for separating carbon dioxide 70 from the ambient air 11. With essentially the same functional structure as described for Figure 7, the system has a 2 + 1 configuration, i.e. two first process chambers 12, 13 connected in parallel for drying the ambient air 11 and a second process chamber 30 for separating carbon dioxide 70 from the ambient air 11. After the first flow generator 24 is switched on, the ambient air 11 flows into the system 10 and the ambient air 11 is dried in the first process chambers 12, 13. The air humidity is separated at the sorption cells 100, 102, 104, 106, 108.Parallel to or subsequently thereto, a gas stream 72 of dried ambient air 11 flows into the second process chamber 30, where the air molecules come into contact with the sorption cells 60, 62, 64, 66, 68 and the adsorption of carbon dioxide molecules on the second sorbent material 38 takes place. When the sorption cells 100, 102, 104, 106, 108 of the first process chamber 12 are saturated with humidity, the flow generator 24 for the other first process chamber 13 switches on and takes over the air drying in the first process chamber 13. At the same time, the regeneration or activation of the sorption cells 100, 102, 104, 106, 108 begins in process chamber 12 according to the method according to the invention. In this context, regeneration or activation means that the first sorbent material 18 of individual sorption cells 60, 62, 64, 66, 68 is freed of water.The water must diffuse out of the sorbent structure so that repeated air drying can be carried out periodically in continuous operation with the sorption cells 100, 102, 104, 106, 108. During the regeneration of the sorption cells 100, 102, 104, 106, 108, the vacuum pump 112 can optionally be switched on for support. In the two process chambers 12, 13 for air drying, a known design solution is implemented to remove the condensate and / or the collected water from the first process chambers 12, 13 via channels, separators, filters, etc.
[0078] To separate carbon dioxide 70 in the second process chamber 30, corresponding sensors are provided, which signal to the control unit 114 that the sorption cells 60, 62, 64, 66, 68 are saturated with carbon dioxide. If this is the case, the second process chamber 30 is decoupled from the gas stream 72, which can be done in particular by suitable shut-off valves, and an evacuation of the second process chamber 30 is initiated by means of the vacuum pump 112 in order to pump out the residual air from the dead volume of the second process chamber 30 so that the adsorbed carbon dioxide 70 is not contaminated. In parallel or subsequently, the control device 114 initiates the desorption of the carbon dioxide 70 from the sorbent material 38 of the second process chamber 30, whereby the carbon dioxide storage 110 is filled with carbon dioxide 70. For this purpose, the sorption cells 60, 62, 64, 66, 68 are heated accordingly.The heating elements 40 integrated into the support elements 36 transfer heat more homogeneously and quickly, without heat transfer or other heat losses, directly from the heating element 40 to the sorbent material 38. The temperature increase to 150–220°C unstables the physical bond between the carbon dioxide molecules and the zeolite, allowing the desorption process to proceed optimally with the vacuum support. Once desorption is complete, an additional temperature increase can optionally be preprogrammed (e.g., to 250°C with a 15-minute ramp). This would result in a slight activation of the sorbent material 38 to remove any residual moisture from the sorbent material 38.
[0079] Figure 9 shows a preferred example for controlling a system 10 according to the invention for drying an air stream from ambient air 11 and for the subsequent separation of carbon dioxide 70 from the ambient air 11. Figure 9 represents a schematic representation of the activation plan of the sorption cells 60, 62, 64, 66, 68 in the second process chamber 30 during the desorption of the carbon dioxide 70. The control of the sorption cells 60, 62, 64, 66, 68 takes place in the form of cascades 50, 52, 54, 56, 58 of sorption cells 60, 62, 64, 66, 68. Each cascade 50, 52, 54, 56, 58 is assigned several sorption cells 60, 62, 64, 66, 68, wherein The sorption cells within a cascade are preferably flowed through in parallel, and the cascades are flowed through serially. At the beginning of the desorption process, the second process chamber 30 has a starting temperature of, for example, 35°C.After the air has been evacuated from the second process chamber 30, the heating elements 40 of the sorption cells 60 of the first cascade 50 are switched on and heat the sorption cells 60 at a heating rate of 30°C / min. After approximately 6 minutes, the sorption cells 60 of the first cascade 50 reach the target value of 200°C. The vacuum pump 112 assists the desorption and ensures that warm carbon dioxide molecules leave the sorption cells 60 and are passed on to the carbon dioxide storage 110. The gas stream transfers heat to the second cascade 62 following downstream in the flow direction. This results in the sorption cells 62 of the second cascade 52 having a higher initial temperature of, for example, 40°C before the heating elements 41 of the sorption cells 62 of the second cascade 52 are activated.This shortens the required heating time from cascade to cascade for the same heating output, with the last cascade 58 having the shortest heating time. Thus, the required activation time of the heating elements 41 is reduced from cascade to cascade, which also reduces energy consumption.
[0080] The cascaded design of the sorption element 34 in the second process chamber 30 allows for a further optimized energy balance during desorption, as the duty cycle (ED) becomes increasingly shorter from cascade to cascade. The power supply to the heating elements 40, 41 of the sorption cells 60, 62, 64, 66 is regulated accordingly, ensuring homogeneous heating within the cascade. The cascaded design and control strategy can also be used for the sorption cells 100, 102, 104, 106, 108 of the first process chamber 12, i.e., for the energy-efficient drying of the ambient air stream 11. Such a system design enables numerous control strategies and can significantly reduce energy consumption.
[0081] Figure 10 shows another possible design for the electrically heatable support element 36, which serves as the heating element 40. It is a heating coil 99, which is connected to a power source 90 and can be controlled with various AC and / or DC pulse profiles. In practical terms, this would mean that a pulsating power supply can generate additional electromagnetic radiation in addition to the heating, which can also support the desorption of carbon dioxide 70 from the sorbent material 38.
[0082] Alternatively, the heating element 40 can also be integrated onto an additional support or a sieve to increase rigidity. Preferred sorbent materials 18, 38 for the sorption cells 60, 62, 64, 66, 68, 100, 102, 104, 106, 108 are physical sorbents such as zeolites, silica materials, MOFs (metal organic frameworks), activated carbon, COFs (covalent organic frameworks), carbon molecular sieves, materials based on alkali metals or metal oxides, ordered porous carbon, ACFs (activated carbon fibers), graphene, CMS (carbon molecular sieves), and composites thereof.
[0083] Alternatively, chemical adsorbents such as potassium carbonate (K2CO3), sodium nitrate (NaNO3), aluminum oxide (Al2O3), zirconium dioxide (ZrCh), titanium dioxide (TiC>2), manganese dioxide (MnCh), zinc oxide (ZnO), and binary eutectic mixtures consisting of potassium nitrate (KNO3) and lithium nitrate (UNO3) can be used as sorbent materials 18, 38. Furthermore, a polymer with a nitrogen-containing functional group, for example, with an amino group or an imine group, can be used as sorbent material 18, 38. Solid sorbents made of one of the following polymers: polyethyleneimine (PEI), polyallylamine (PAA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), or polyethyleneimine-modified silica (gel) are also possible. A (macroporous) divinylbenzene-crosslinked polymer with primary amino groups is particularly preferred as a solid sorbent. An example of a (macroporous) divinylbenzene-crosslinked polymer with primary amino groups is Lewatit® VP OC 1065.
[0084] Depending on which sorbent material 18, 38 is used to produce a sorption cell 60, 62, 64, 66, 68, 100, 102, 104, 106, 108, other directly heatable methods or heating elements 40 could also be used as electrically heatable supports 36 of a sorption cell 60, 62, 64, 66, 68, 100, 102, 104, 106, 108. Figure 11 shows a collection of possible heating elements 40 in the form of heating mats 92, which can be used to construct a sorption cell 60, 62, 64, 66, 68, 100, 102, 104, 106, 108 for a process chamber 12, 13, 30. In particular, a heating mat 92 with an integrated heating wire 98 or a heating fabric 96, in particular a carbon heating fabric or a heating surface 94, in particular a carbon heating surface, can be used.
[0085] Figure 12 shows a preferred variant of a heatable carrier 36 with a carrier material 116 with a coating 118 with a sorbent material 38. The carrier material 116, in particular a wire mesh, is simultaneously the heating element 40. The wire mesh comprises warp threads and weft threads which form the wire mesh. In the embodiment shown in Figure 12, the warp threads 76 contained in the wire mesh are used as the heating element 40. Alternatively, Kanthai wire, among others, can be used as the heating element. The weft thread 78 can consist of a different (even non-conductive) material which, for example, is cheaper, has better thermal conductivity or better adhesive properties than the sorbent material 38. Using the weft wire as a heating thread is also conceivable.
[0086] Another possible embodiment of heating the wire mesh, in which the weft threads 78 are electrically heated, is shown in Figure 13. In this case, the weft thread 78 is designed and heated as a circulating wire.
[0087] The current is fed into and out of the wire mesh from a power source 90 via busbars 74. Alternatively, an embodiment is possible in which both the warp threads 76 and the weft threads 78 are electrically heated. In this case, the intersection points of the warp and weft wires are to be brought into the best possible electrical contact, either by pressing (calendering the wire mesh), by gluing, or by welding.
[0088] Figure 14 shows a flow diagram for the production of a sorption cell 60 according to the invention. In one process step <200> a carrier 36 made of an electrically conductive material is provided. In a process step <210> A sorbent material 38 is provided for adsorbing carbon dioxide from the ambient air. In one process step <220> A heating element 40 is provided for electrically heating the carrier 36. The process steps <200> , <210> and <220> can be carried out in any order or in parallel. The heating element 40 can also be integrated into the carrier 36, or the carrier 36 itself can form the heating element 40. In one process step <230> the carrier 36 is coated with the sorbent material 38, in particular with the sorbent material 38.The heating element 40 is arranged in such a way that the carrier 36 coated with the sorbent material 38 can be heated by the electric heating element 40. In a one-piece design, this is preferably done by coating both sides of the carrier 36 with the sorbent material 38. In a multi-piece design of the sorption cell 60, the heating element 40 is coated in one process step <240> Preferably, the heating element 40 is arranged upstream of the carrier 36 in the direction of flow and connected to it in order to achieve particularly efficient heating of the carrier 36 through thermal conduction, convection, and thermal radiation. In a one-piece design in which the heating element 40 is integrated into the carrier 36, this process step is omitted.
[0089] List of reference symbols
[0090] Plant for the separation of carbon dioxide from the ambient air
[0091] Ambient air first process room first process room
[0092] Adsorption chamber first sorption element first sorbent material
[0093] Supporting frame
[0094] heat exchanger
[0095] Flow generator
[0096] fan
[0097] Pressure reduction unit second process chamber
[0098] Intermediate element second sorption element metallic carrier second sorbent material first heating element second heating element
[0099] pressure sensor
[0100] Temperature sensor
[0101] Gas sensor second flow generator first cascade second cascade third cascade fourth cascade further cascade first sorption cell second sorption cell third sorption cell fourth sorption cell fifth sorption cell
[0102] Carbon dioxide
[0103] Gas flow
[0104] Busbar
[0105] warp thread
[0106] Weft thread first cascade second cascade third cascade fourth cascade further cascade
[0107] Power source heating mat
[0108] Carbon heating surface
[0109] Carbon heating fabric heating wire
[0110] Heating coil first sorption cell second sorption cell third sorption cell fourth sorption cell fifth sorption cell
[0111] Carbon dioxide storage
[0112] Vacuum pump Control device Carrier material Coating Power device Power supply Opening Circumferential surface
Claims
Patent claims 1. Sorption cell (60) for a system (10) for separating a gas and / or humidity from the ambient air (11), comprising a carrier (36) made of an electrically conductive material, and a sorbent material (38) for absorbing the gas to be absorbed or the humidity from the ambient air (11), which encases the carrier (36), and an electrical heating element (40) for heating the sorbent material (38) to a desorption temperature (TD) or a regeneration temperature (TR).
2. Sorption cell (60) according to claim 1, wherein the carrier (36) is coated with the sorbent material (38) or wrapped with the sorbent material (38).
3. Sorption cell (60) according to claim 1 or 2, wherein the electrical heating element (40) is integrated into the carrier (36).
4. Sorption cell (60) according to one of claims 1 to 3, wherein the electrical heating element (40) is designed as a heating coil (99), a heating mat (92) or a heating fabric (96).
5. Sorption cell (60) according to one of the preceding claims, wherein the heating element (40) comprises a wire mesh of warp threads (76) and weft threads (78), wherein either the warp threads (76) or the weft threads (78) or both the warp threads (76) and the weft threads (78) are designed as heating wires (98).
6. Sorption cell (60) according to claim 5, wherein the heating element (40) comprises a wire mesh of heating wires (98) and wires, ribbons or threads different from the heating wires (98).
7. Sorption cell (60) according to claim 5 or 6, wherein the heating wires (98) are connected to one another via a busbar (74).
8. Sorption cell (60) according to one of the preceding claims, wherein the carrier (36) has a connection for a power supply (122).
9. Sorption cell (60) according to one of the preceding claims, wherein a peripheral surface (126) of the sorption cell (60) is molded uniformly and substantially flawlessly with sorbent material (38).
10. Sorption cell (60) according to one of the preceding claims, wherein the carrier is designed as a fine wire mesh, wherein openings (124) are formed between the wires of the fine wire mesh, through which openings a gas stream (72) is guided for separating gas to be adsorbed and / or dried in the gas stream (72).
11. Sorption cell (60) according to claim 10, wherein the openings (124) are distributed substantially uniformly over the surface of the sorption cell (60).
12. Sorption cell (60) according to one of the preceding claims, wherein the sorbent material (38) is a physisorbent or a chemisorbent.
13. Plant (10) for separating a gas and / or air humidity from the ambient air (11), comprising a flow generator (24) for conveying the ambient air (11) through the plant (10), a first process chamber (12) for drying the ambient air (11) and a second process chamber (30) downstream of the first process chamber (12) in the flow direction for separating carbon dioxide (70) from the ambient air (11) dried in the first process chamber (12), wherein a sorption cell (60) according to one of claims 1 to 12 is arranged in at least one of the two process chambers (12, 30).
14. Plant according to claim 13, wherein in one of the process spaces (12, 30) a sorption element (16, 34) is arranged, which comprises a plurality of heatable sorption cells (60, 62, 64, 66, 68) which are arranged in the flow direction of a gas stream (72) through the process space (12, 30) in at least two different cascades (50, 52, 54, 56, 58), as well as at least two heating elements (40, 41), wherein each cascade (50, 52, 54, 56, 58) is assigned at least one heating element (40, 41), wherein the ambient air (11) flows through the cascades (50, 52, 54, 56, 58) in series, such that the waste heat of the sorption cells (60) of the first cascade (50) is transferred to the sorption cells (62) of the second cascade (52).
15. A method for producing a sorption cell (60) for a system (10) for separating a gas and / or humidity from the ambient air (11), comprising the following process steps: Providing a carrier (36) made of an electrically conductive material, Providing a sorbent material (38) for absorbing carbon dioxide (70) from the ambient air (11), Providing an electric heating element (40), Coating the carrier (36) with the sorbent material (38), Arranging the electrical heating element (40) such that the carrier (36) coated with the sorbent material (38) can be heated by the electrical heating element (40).