Drying apparatus and method of operation thereof, and DAC system

Abstract

The invention relates to a drying apparatus (1) for regeneration of an adsorber material (15) by heating, in particular for reducing a carbon dioxide content in the adsorber material (15), preferably for use in a DAC (direct air capture) system (20) for removing carbon dioxide from ambient air, comprising a regenerator chamber (2) for accommodating the adsorber material (15) and a discharge device (3), connected to the regenerator chamber (2), for discharging gases released from the adsorber material (15), in particular carbon dioxide and / or water vapor, from the regenerator chamber (2).

Description

[0001] R. 414413

[0002] - 1 -

[0003] Description

[0004] Drying device and method for its operation as well as DAC system

[0005] Technical field

[0006] The invention relates to a drying device for regenerating an adsorbent material, particularly in a DAC system. The invention further relates to a DAC system with a drying device and a method for operating a drying device.

[0007] State of the art

[0008] To limit the warming of the Earth's atmosphere, it is already known to actively reduce the concentration of carbon dioxide in the atmosphere. So-called "Direct Air Capture" (DAC) systems can be used for this purpose (source: https: / / de.wikipedia.org / wiki / Direct_Air_Capture). Such a system is characterized in principle by the fact that, in a first stage, carbon dioxide is actively separated from the ambient air by adsorption and bound using an adsorbent material. In a second stage, the carbon dioxide is removed from the carbon dioxide-enriched adsorbent material in a desorption process, so that the carbon dioxide can subsequently be permanently bound, e.g., by injecting it into geological cavities.

[0009] Furthermore, EP 3725391 B1 discloses a DAC plant with a drying device having the features of the preamble of claim 1. EP 3725391 B1 teaches how to carry out an adsorption and desorption process of carbon dioxide in a plant which has several chambers containing adsorbent material. In a first operating mode, the adsorption chambers are perfused with ambient air to transfer the carbon dioxide to the adsorbent material. R. 414413

[0010] - 2 -

[0011] Individual chambers of the system can be sealed or evacuated from the environment using appropriate devices to enable carbon dioxide desorption from the adsorbent material under the influence of negative pressure and / or heat in a second operating mode. For this purpose, the chamber or the adsorbent material is heated to a temperature of typically around 100°C. It is known from the known device or system to permeate the chamber with heat-conducting elements (pipes) that serve to guide a heat transfer medium, in particular a heat transfer fluid. This entails considerable technical complexity and consequently high costs. Furthermore, the volume of the heat-conducting elements in the chambers reduces the chamber's capacity for the adsorbent material, meaning that the chamber must be relatively large for a given quantity of adsorbent material.

[0012] The object of the invention is to overcome the aforementioned disadvantages of the prior art and to propose an efficient heating of the adsorber material, particularly with regard to energy efficiency and space efficiency.

[0013] Disclosure of the invention

[0014] The drying device according to the invention, with the features of claim 1, has the advantage that energy for heating an adsorbent material can be introduced very precisely into the adsorbent material in a regenerator chamber, and that the construction of the drying device is particularly simple. Furthermore, no components are necessary in the regenerator chamber for heating the adsorbent material, so that the volume of the regenerator chamber can be filled with adsorbent material particularly efficiently.

[0015] The drying device according to the invention for regenerating an adsorber material by means of heating, in particular for reducing the content of a gas, especially carbon dioxide, in the adsorber material, preferably for use in a gas separation device, in particular a DAC plant for removing carbon dioxide from ambient air, comprises a regenerator chamber for receiving the adsorber material and a [missing information - likely a reference to R. 414413].

[0016] - 3 -

[0017] Regenerator chamber connected to a discharge device for removing gases released from the adsorber material, in particular carbon dioxide and / or water vapor, from the regenerator chamber.

[0018] According to the invention, the drying device comprises a microwave generator which is microwave-conductingly connected to the regenerator chamber, so that the adsorber material in the regenerator chamber can be irradiated with microwaves, in particular heated by microwave energy.

[0019] Advantageous further developments of the drying device according to the invention are listed in the dependent claims.

[0020] In a first preferred embodiment, the microwave generator can be configured as a magnetron. A magnetron offers a particularly efficient and cost-effective method for generating microwaves. The power and frequency of a magnetron are largely determined by its mechanical design and therefore remain constant even over extended periods of operation. For the present application, a constant frequency and power of microwave generation are sufficient, which is why a magnetron is advantageously suited for this purpose.

[0021] In a further preferred embodiment, the magnetron can be configured with a central, cylindrical cathode and an anode radially surrounding the cathode, wherein an annular gap is formed between the cathode and the anode, and at least one cylindrical cavity in the anode is formed as a resonator parallel to the cathode, the resonator being connected to the annular gap by a slot-shaped opening along one longitudinal side of the resonator. This configuration allows for advantageously simple manufacturing of the magnetron. Advantageously, the magnetron has at least six resonators.

[0022] In a further preferred embodiment, sensor means can be arranged in operative connection with the regenerator chamber and configured to detect an electromagnetic voltage wave emanating from the microwave generator, so that an interaction of the microwave generator with R. 414413

[0023] - 4 -

[0024] The state of the adsorber material in the regenerator chamber can be detected. During the regeneration process, the dielectric properties of the adsorber material change, which affects its interaction with the microwave generator. Therefore, the state of the adsorber material can be determined indirectly and particularly easily via its interaction with the microwave generator.

[0025] Particularly advantageous is the arrangement of the sensor means in such a way that the regenerator chamber is not affected by the sensor means, so that, for example, no sensor means arranged in the regenerator chamber impede the filling of the regenerator chamber with adsorbent material. Advantageously, sensor means designed in this way can enable the detection of the condition of the adsorbent material without requiring direct contact between the sensor means and the adsorbent material.

[0026] In a further and advantageously improved embodiment, the sensor means for detecting the permittivity of the adsorber material in the regenerator chamber can be configured and preferably designed as a directional coupler. The permittivity of the adsorber material depends on its regeneration state. The permittivity decreases with progressive regeneration. It is possible to link a permittivity threshold to a target regeneration value of the adsorber material, so that sufficient regeneration of the adsorber material can be detected when this threshold is reached. A directional coupler is a proven and advantageous component for detecting microwaves and thus for detecting the interaction of microwaves with a material irradiated by microwaves.

[0027] In a further preferred embodiment, a magnetron resonator can be at least partially configured as a regenerator chamber and filled with the adsorbent material. The magnetron resonator is designed as a cavity. Using this cavity as a regenerator chamber allows for an advantageously compact design of the drying device. A regenerator chamber can be configured as a vessel arranged within a resonator, which is mechanically sealed to the adsorbent material, with one wall of the vessel being made of an electrically non-conductive material, such as plastic, ceramic, or glass. Alternatively, an inner surface of the resonator can be made electrically conductive by a layer of such a material.

[0028] - 5 -

[0029] The resonator can be constructed of non-conductive material, and / or it can be rigidly connected to this layer, so that the resonator forms the vessel. A magnetron as a microwave generator and the regenerator chamber are thus advantageously combined in a single unit. Furthermore, the transmission of microwave energy is particularly low-loss because the use of microwave energy is spatially linked to the generation of microwaves, thus minimizing a lossy transmission path. To implement this design, a suitable means is required for filling the resonator with adsorbent material and for removing the regenerated adsorbent material from the regenerator chamber located within the resonator. For example, a dosing scale is suitable for this purpose.

[0030] In a further preferred embodiment, the drying device can include sensing electronics that detect the frequency response of the magnetron and make it available for evaluation. The filling of the magnetron's resonator influences its frequency response. This applies to both the quantity and the regeneration state of the adsorbent material located in the resonator. By detecting the magnetron's frequency response, it is therefore technically possible and easy to determine the regeneration state of the adsorbent material.

[0031] In a further preferred embodiment, a mode barrier can be arranged to delimit the regenerator chamber in a magnetron resonator, wherein the mode barrier is permeable to the adsorber material. A mode barrier limits the space in which the generated microwaves propagate within the resonator. It is therefore made of electrically conductive material. Sufficiently large openings in the mode barrier allow adsorber material to pass through it without being permeable to microwaves. This design advantageously eliminates the need for mechanically moving parts in the magnetron, which improves durability, reliability, and cost. For example, no movable seal is required to fill the resonator with adsorber material and to contain microwaves within the resonator.This makes it possible, for example, to fill the resonator with adsorber material using the effect of gravity or to remove adsorber material from the resonator to R. 414413.

[0032] - 6 -

[0033] It is also advantageous to be able to fill and / or remove adsorbent material during operation of the magnetron.

[0034] To prevent microwaves, or a significant portion thereof, from unintentionally escaping the regenerator chamber during microwave operation, the regenerator chamber preferably has a covering device for closing and / or covering openings, in particular inlet and outlet openings, of the regenerator chamber, e.g., at the exhaust unit. The covering device can, for example, comprise a metallic grid or similar material that does not allow microwaves to pass through.

[0035] The invention further relates to a gas separation device, in particular a DAC system, comprising a drying device according to the invention.

[0036] The gas separation device or DAC system has the advantage of being particularly simple in design and enables particularly energy-efficient operation.

[0037] In a first preferred embodiment, the gas separation device, in particular a DAC system, can comprise the following components and / or assemblies: an adsorber unit through which the gas to be treated can flow; conduit for conveying adsorber material from the drying device to the adsorber unit and from the adsorber unit to the drying device; conveying means for conveying the adsorber material in the conduit; and preferably, a storage means for storing adsorber material. Such a design of a DAC system enables continuous operation of the DAC system, with the adsorber material being used in a closed loop. This results in a significantly lower requirement for adsorber material. Furthermore, the adsorber material can be used for an advantageously long time before it needs to be replaced, which advantageously reduces costs and improves the environmental performance of the DAC system.Storage devices for adsorbent material are also advantageous, as they allow for the separation of the operation of the adsorbent unit from the operation of the drying device. For example, energy-intensive regeneration of the adsorbent material can be carried out when energy prices, especially electricity prices, are low, while the operation of the adsorbent unit can run continuously. For a DAC system that is as compact and mechanically simple as possible, see R. 414413.

[0038] - 7 -

[0039] The adsorber unit and a drying device are combined in a single unit, saving space and components such as piping and / or conveying equipment. In a first operating mode, ambient air flows through the adsorber material in the adsorber unit to bind the gas, especially carbon dioxide. In a second operating mode, the adsorber material can be irradiated with microwaves to selectively release the bound carbon dioxide.

[0040] The invention further relates to a method for operating a drying device, in particular a drying device designed according to the present invention. Advantageously, the method enables a particularly targeted and efficient heating of the adsorbent material.

[0041] According to the invention, the method provides that an adsorber material is irradiated with microwaves in a regenerator chamber, in particular heated by microwave energy, whereby a regeneration of the adsorber material is carried out using microwave energy.

[0042] In a first preferred embodiment, the regeneration of the adsorber material can be carried out batchwise. Batch regeneration of the adsorber material requires a significantly lower level of plant engineering effort. It is technically simple to fill a regenerator chamber with a defined quantity of adsorber material and then irradiate it with microwave energy until a target regeneration state is reached. Subsequently, it is equally simple to empty the regenerator chamber and make the regenerated adsorber material available again for carbon dioxide adsorption. Batch, discontinuous regeneration of the adsorber material works advantageously in conjunction with discontinuous operation of the adsorber unit.Furthermore, the use of storage agents for adsorbent material can support discontinuous, batch-based regeneration of the adsorbent material. R. 414413.

[0043] - 8 -

[0044] In an alternative embodiment, the regeneration of the adsorbent material can be carried out continuously. Continuous operation of the adsorbent material regeneration process can advantageously maximize the throughput of regenerated adsorbent material and thus the overall performance of the DAC system. For example, it is possible to continuously feed adsorbent material through a regenerator chamber, with the feed rate influencing the residence time in the regenerator chamber and thus the degree of regeneration. A sensor designed to detect the feed rate of the adsorbent material through the regenerator chamber can measure the feed rate and thus indirectly the residence time, allowing the feed rate to be controlled to achieve a target regeneration level.For example, it is possible to convey the adsorber material through the regenerator chamber by gravity, whereby a controlled and / or regulated withdrawal from the regenerator chamber creates a backflow, so that the residence time or the conveying speed through the regenerator chamber can be influenced.

[0045] Advantageously, an electromagnetic voltage wave emanating from the microwave generator is detected by means of a sensor device which is arranged in operative connection with the regenerator chamber in order to detect an interaction of the microwave generator with the adsorber material in the regenerator chamber.

[0046] Advantageously, the permittivity of the adsorber material in the regenerator chamber is also determined. Preferably, the frequency response of the microwave generator, which is in particular designed as a magnetron (5), is determined.

[0047] Features disclosed by process shall be considered as disclosed by device as well and shall be claimable, and vice versa.

[0048] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments of the invention and from the drawings. R. 414413

[0049] - 9 -

[0050] Brief description of the drawings

[0051] Fig. 1 shows a schematic representation of a device according to the invention.

[0052] drying device,

[0053] Fig. 2 shows a schematic representation of the basic structure of a magnetron,

[0054] Fig. 3 shows a schematically represented magnetron, with a resonator designed as a regenerator chamber,

[0055] Fig. 4 shows a schematic representation of a DAC system according to the invention.

[0056] Embodiments of the invention

[0057] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0058] Figure 1 shows a schematic representation of a drying device 1. A regenerator chamber 2 is filled with an adsorbent material 15. A microwave generator 4, which in this example is a magnetron 5, is connected to the regenerator chamber 2 by means of a microwave conductor 17. A sensor 6, which in this example is a directional coupler 7, is also connected to the regenerator chamber 2. During operation of the drying device 1, microwaves 16 are generated by the microwave generator 4 and introduced into the regenerator chamber 2 by means of the microwave conductor 17, so that the adsorbent material 15 is irradiated with the microwaves 16 and thereby heated. The heating of the adsorbent material 15 releases carbon dioxide, which is removed from the regenerator chamber 2 by means of a discharge device 3.The removed carbon dioxide can be used for technical purposes or disposed of / stored in a final repository. The regeneration status of the adsorber material 15 is indirectly monitored by the directional coupler 7 via its interaction with the microwave generator 4. R. 414413.

[0059] - 10 -

[0060] Figure 2 shows a schematic representation of the basic structure of a magnetron 5 in a sectional view. A cylindrical cathode 11 is arranged centrally in the magnetron 5. The cathode 11 is surrounded by an annular gap 13, which separates the cathode 11 from a concentric anode 12. Resonators 8 are designed as axially parallel bores in the anode 12.

[0061] The resonators 8 are connected to the annular gap 13 by means of slot-shaped, axially parallel openings 14. A magnet for generating a magnetic field acting in the space between the anode 12 and cathode 11 is not shown. Depending on the geometric design of the magnetron 5, electromagnetic waves with a frequency of approximately 0.3 GHz to 95 GHz are generated during operation.

[0062] Figure 3 shows a top view of components of a magnetron 5 with resonators 8 configured as regenerator chambers 2. A cathode 11 is arranged centrally in the magnetron 5. The view is oriented at a small angle to the axis of the central cathode 11. The magnetron 5 is axially closed by a termination element 18. The termination element 18 has ten openings, each equipped with mode-blocking elements 10, allowing adsorber material to be added to or removed from resonators 8 with regenerator chambers 2 located behind the openings. The mode-blocking elements 10 are cross-shaped and prevent microwaves 16 from escaping the resonators 8. It is readily apparent that a free-flowing adsorber material 15 can be poured through the mode-blocking elements 10 into a regenerator chamber 2 formed within a resonator. The anode 12, which surrounds the cathode 11, is covered by the terminal element 18.The anode 12 has ten resonators 8.

[0063] Figure 4 schematically shows a structure of a DAC system 20 according to the invention. The DAC system 20 has an adsorber unit 21 through which a gas 25 to be treated can flow. The gas 25 to be treated can, in particular, be ambient air. The adsorber unit 21 is connected to the drying device 1 by means of conduits 22. The drying device 1 is also connected to the adsorber unit 21 by means of conduits 22. The DAC system 20 forms a closed circuit for adsorber material 15. The adsorber material is conveyed through this circuit by means of a conveying means 23.

[0064] - 11 -

[0065] The adsorber material 15 is circulated in a cycle 15. Storage media 24 are arranged between the adsorber unit 21 and the drying device 1, and between the drying device 1 and the adsorber unit 21. In the interconnected components of the DAC system 20, the adsorber material 15 is used multiple times to adsorb carbon dioxide 26 and is subsequently regenerated. The drying device 1 has a magnetron 5 with resonators designed as a regenerator chamber and a detection electronics unit 9. The detection electronics unit 9 is designed to detect the frequency response of the magnetron 5, so that the drying state of the adsorber material 15 in the magnetron 5 can be detected. A discharge device 3 removes the separated carbon dioxide 26 from the drying device 1.The storage means 24 enable the regeneration of the adsorber material 15 in the drying device 1 to be carried out independently of the operation of the adsorber unit 21.

Claims

R. 414413 - 12 - Claims 1. Drying device (1) for regenerating an adsorber material (15) by heating, in particular for reducing the content of a gas, preferably carbon dioxide, in the adsorber material (15), preferably for use in a gas separation device (20), in particular a DAC (Direct Air Capture) system (20) for extracting carbon dioxide from ambient air, comprising a regenerator chamber (2) for receiving the adsorber material (15) and a discharge device (3) connected to the regenerator chamber (2) for removing gases released from the adsorber material (15), in particular carbon dioxide and / or water vapor, from the regenerator chamber (2), characterized by that the drying device (1) comprises a microwave generator (4) which is microwave-conductingly connected to the regenerator chamber (2) so that the adsorber material (15) in the regenerator chamber (2) can be irradiated with microwaves (16), in particular heated by microwave energy.

2. Drying device according to claim 1, characterized by that the microwave generator (4) is designed as a magnetron (5).

3. Drying device according to claim 2, characterized by that the magnetron (5) is formed with a central, cylindrical cathode (11) and an anode (12) radially surrounding the cathode (11), wherein an annular gap (13) is formed between the cathode (11) and the anode (12), and in the anode (12) at least one cylindrical cavity is formed as a resonator (8) axially parallel to the cathode (11), wherein the resonator (8) is formed by a slot-shaped R. 414413 - 13 - The opening (14) is connected along a longitudinal side of the resonator (8) to the annular gap (13).

4. Drying device according to one of claims 1 to 3, characterized by that a sensor means (6) is arranged in operative connection with the regenerator chamber (2) and is set up to detect an electromagnetic voltage wave emanating from the microwave generator (4), so that an interaction of the microwave generator (4) with the adsorber material (15) in the regenerator chamber (2) can be detected.

5. Drying device (1) according to claim 4, characterized by that the sensor means (6) is configured to detect a permittivity of the adsorber material (15) in the regenerator chamber (2) and is preferably designed as a directional coupler (7).

6. Drying device according to claim 2 or 3, characterized by that a resonator (8) of the magnetron (5) is at least partially designed as a regenerator chamber (2) and can be filled with the adsorber material (15).

7. Drying device according to claim 6, characterized by that the drying device (1) includes a detection electronics (9) which detects the frequency behavior of the magnetron (5) and makes it available for evaluation.

8. Drying device according to claim 6 or 7, characterized by that a mode barrier (10) is arranged to limit the regenerator chamber (2) in the resonator (8) of the magnetron (5), wherein the mode barrier (10) is designed to be permeable to the adsorber material (15).

9. Drying device according to one of the preceding claims, R. 414413 - 14 - characterized in that the regenerator chamber (2) comprises a covering device for closing and / or covering openings, in particular inlet and outlet openings of the regenerator chamber (2).

10. Gas separation device (20), in particular DAC (Direct-Air-Capturing) system (20), comprising a drying device (1) configured according to any one of claims 1 to 9.

11. Gas separation device (20) according to claim 10, characterized by that the gas separation device (20) comprises the following components and / or assemblies: an adsorber unit (21) in which adsorber material (15) can be permeated by gas (25) to be treated, in particular ambient air, a conduit (22) for conveying adsorber material (15) from the drying device (1) to the adsorber unit (21) and from the adsorber unit (21) to the drying device (1), a conveying means (23) for conveying the adsorber material (15) in the conduit (22) and preferably a storage means (24) for storing adsorber material (15).

12. Method for operating a drying device (1), which is designed in particular according to one of claims 1 to 9, characterized by that an adsorber material (15) is irradiated with microwaves (16) in a regenerator chamber (2), in particular heated by microwave energy, whereby a regeneration of the adsorber material (15) is carried out by means of microwave energy.

13. Method according to claim 12, characterized by that the regeneration of the adsorber material (15) is carried out batchwise or continuously.

14. Method according to claim 12 or 13, characterized by R. 414413 - 15 - that an electromagnetic voltage wave emanating from the microwave generator (4) is detected by means of a sensor means (6) which is arranged in operative connection with the regenerator chamber (2) in order to detect an interaction of the microwave generator (4) with the adsorber material (15) in the regenerator chamber (2).

15. Method according to claim 14, characterized by that, furthermore, a permittivity of the adsorber material (15) is determined in the regenerator chamber (2).

16. Drying device according to claim 15, characterized by that the frequency response of the microwave generator (4), which is designed in particular as a magnetron (5), is recorded.

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