Gas-solid contactor for direct capture of carbon dioxide in air, control method and modular stacking structure

Abstract

The application provides a gas-solid contactor for directly capturing carbon dioxide in air, a control method and a modular stacking structure, mainly comprising a fluidized bed container, a gas pre-distributor, a gas distributor and an adsorbent bed. The fluidized bed container is provided with a gas inlet at the lower part and a gas outlet at the upper part. The gas pre-distributor is arranged in the container and communicates with the gas inlet. The gas distributor is arranged above the pre-distributor. The adsorbent bed is arranged between the gas distributor and the gas outlet. The top and bottom of the fluidized bed container are respectively provided with a top cover and a base which can be connected with each other, so that multiple containers can be vertically stacked through the top cover and the base. A water collecting tank is arranged on the base and is communicated with a drain pipe penetrating through the base. The application solves the problems of low gas-solid mass transfer and heat transfer efficiency, high energy consumption and uneven temperature distribution in the prior art, and has the advantages of high capture efficiency, low operation energy consumption, uniform temperature distribution and easy modular expansion.

Description

Technical Field

[0001] This application relates to the field of gas adsorption and separation technology, and in particular to a gas-solid contactor, control method, and modular stacking structure for directly capturing carbon dioxide from the air. Background Technology

[0002] Direct air capture (DAC) is a technology that captures carbon dioxide (CO2) from the atmosphere. By directly capturing CO2 from the air rather than other CO2 emission sources, it can effectively reduce atmospheric CO2 concentration and mitigate the greenhouse effect. As a typical negative carbon technology that can effectively promote the achievement of carbon neutrality goals, the application prospects of DAC technology have been widely recognized by the academic and industrial communities both domestically and internationally.

[0003] Currently, solid adsorbent-based DAC technology mainly uses fixed beds or honeycomb packed beds as gas-solid contactors. The gas-solid contactor is the core equipment of the DAC device, where the mass and heat transfer processes between the gas and particles are completed during the adsorption and desorption stages. Fixed-bed contactors typically use large adsorbent particles (millimeters or larger), resulting in high mass transfer resistance within the particles and slow adsorption and desorption rates. Simultaneously, the pressure drop in the bed increases significantly at high gas velocities, leading to high power consumption for device operation. Furthermore, uneven temperature distribution easily forms within the fixed bed, creating localized hot spots and affecting adsorbent lifespan. While honeycomb packed bed contactors have lower pressure drops, their effective adsorbent loading is typically lower. A large amount of inert matrix is ​​repeatedly heated and cooled during the adsorption-desorption cycle, easily causing thermal energy waste, thus requiring higher energy consumption for the capture process.

[0004] Existing technologies also employ moving bed solutions, but moving beds also face problems such as low mass and heat transfer efficiency due to large particles, high bed pressure drop, and difficulty in ensuring uniform particle flow.

[0005] Therefore, how to overcome the shortcomings of the existing technology mentioned above has become the subject of this application. Summary of the Invention

[0006] The purpose of this invention is to provide a gas-solid contactor, control method, and modular stacking structure for directly capturing carbon dioxide from the air. This invention can significantly improve gas-solid mass and heat transfer efficiency, reduce overall energy consumption, ensure uniform bed temperature distribution, simplify system structure, and improve system operational stability.

[0007] In a first aspect, embodiments of this application provide a gas-solid contactor for directly capturing carbon dioxide from the air, comprising:

[0008] A fluidized bed container, the fluidized bed container including a gas inlet and a gas outlet formed on the container wall, the gas inlet being located below the gas outlet;

[0009] A gas pre-distributor is located inside the fluidized bed container and is connected to the gas inlet;

[0010] A gas distributor is disposed inside the fluidized bed container and located above the gas pre-distributor;

[0011] An adsorbent bed is disposed inside the fluidized bed container and located between the gas distributor and the gas outlet;

[0012] The fluidized bed container is provided with a top cover and a base that can be connected to each other at the top and bottom, and multiple fluidized bed containers can be stacked vertically through the top cover and the base;

[0013] The base is provided with a water collection tank, and the water collection tank is connected to a drain pipe that passes through the base.

[0014] In one possible implementation, the gas pre-distributor includes a main gas pipe and a plurality of gas branches connected to the main gas pipe, the main gas pipe being connected to the gas inlet.

[0015] In one possible implementation, the gas distributor includes a gas distribution plate and a plurality of gas holes formed on the gas distribution plate, the gas distribution plate being installed on the inner wall of the fluidized bed container.

[0016] In one possible implementation, the inner wall of the fluidized bed container is provided with a heat insulation layer.

[0017] In one possible implementation, both the top cover and the base are provided with flange structures;

[0018] When multiple fluidized bed containers are stacked, the top cover and the base of adjacent fluidized bed containers are connected by the flange structure.

[0019] In one possible implementation, the adsorbent bed comprises micron-sized adsorbent particles, and the bed is in a fluidized state during adsorption operation, with an apparent gas velocity ranging from 0.3 to 1.2 m / s.

[0020] Secondly, embodiments of this application provide a control method for a gas-solid contactor that directly captures carbon dioxide from the air, the control method comprising the following steps:

[0021] Adsorption step: Open the gas inlet and introduce air into the fluidized bed container so that CO2 in the air comes into contact with the adsorbent particles in the fluidized state and is adsorbed.

[0022] Vacuum purification step: Close the gas inlet, turn on the vacuum pump connected to the gas outlet, and reduce the absolute pressure inside the fluidized bed container to 0.4~0.9 atmospheres to remove residual air components;

[0023] Heating desorption step: Close the gas outlet and introduce a high-temperature medium through the gas inlet to raise the temperature of the adsorbent particles to the desorption temperature, thereby desorbing the adsorbed CO2 gas;

[0024] Vacuum purging steps: Close the gas inlet, turn on the gas outlet and the vacuum pump connected to the gas outlet, extract the desorbed CO2 gas and transport it to the subsequent processing unit until the absolute pressure in the fluidized bed container drops to 0.4~0.9 atmospheres; turn on the vacuum pump connected to the drain pipe to remove the condensate generated by water vapor condensation during the heating and desorption stage.

[0025] In one possible implementation, the gas-solid contactor cyclically performs the adsorption step, the vacuum impurity removal step, the heating desorption step, and the vacuum purging step;

[0026] The vacuum purification step, the heating desorption step, and the vacuum purging step are non-adsorption steps.

[0027] In one possible implementation, the method further includes:

[0028] The gas-solid contactors are controlled to alternately perform adsorption and non-adsorption steps, such that at any given time, at least one gas-solid contactor module is in the adsorption step, while the remaining gas-solid contactors are in the non-adsorption step.

[0029] After one of the gas-solid contactors completes the adsorption step, the gas-solid contactor is controlled to switch to the non-adsorption step, and simultaneously another gas-solid contactor that has completed the non-adsorption step is controlled to switch to the adsorption step.

[0030] Thirdly, embodiments of this application provide a modular stacked structure for directly capturing carbon dioxide from the air, comprising:

[0031] Multiple standard modules of the aforementioned gas-solid contactor for direct capture of carbon dioxide from the air are vertically stacked via flange connections.

[0032] Compared with the prior art, the beneficial effects of this application are at least as follows:

[0033] This application employs a gas pre-distributor, a gas distributor, and an adsorbent bed sequentially arranged inside a fluidized bed container. The gas pre-distributor is connected to the gas inlet, and the gas distributor is located above the pre-distributor to ensure uniform gas distribution. Furthermore, the use of micron-sized particles with smaller diameters and larger specific surface areas allows for more thorough contact between the gas and adsorbent particles compared to fixed-bed or moving-bed contactors in related technologies. This significantly increases the gas-solid mass and heat transfer area, thereby substantially improving the adsorption and desorption rates of carbon dioxide and effectively enhancing the production efficiency of the device.

[0034] Because the fluidized bed vessel has a top cover and a base that can be connected to each other, multiple vessels can be vertically stacked and connected via flanges on the top cover and the base. Compared to traditional single large reactors or multiple reactors arranged in a planar layout, this application can flexibly expand modularly according to the gas processing capacity requirements, thereby greatly saving the footprint of the device and reducing equipment layout costs, thus facilitating the miniaturized deployment and large-scale industrial application of the device. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] Figure 1 A schematic diagram of the structure of a gas-solid contactor for directly capturing carbon dioxide from the air, provided in an embodiment of this application;

[0037] Figure 2 This is a schematic diagram of the structure of the gas pre-distributor provided in the embodiments of this application;

[0038] Figure 3 This is a schematic diagram of the structure of the gas distribution plate provided in the embodiments of this application;

[0039] Figure 4 This is a schematic diagram of the structure of the top cover and the base provided in the embodiments of this application;

[0040] Figure 5 This is a schematic diagram of the vessel wall insulation layer structure provided in the embodiments of this application;

[0041] Figure 6 A schematic diagram of the standardized module structure provided in the embodiments of this application;

[0042] Figure 7 This is a schematic diagram of a structure in which multiple modules are stacked vertically, as provided in an embodiment of this application.

[0043] Explanation of reference numerals in the attached figures:

[0044] 100: Fluidized bed container; 110: Gas inlet; 120: Gas outlet; 200: Gas pre-distributor; 210: Gas main pipe; 220: Gas branch pipe; 300: Gas distributor; 310: Gas distribution plate; 320: Vent; 400: Adsorbent bed; 500: Top cover; 600: Base; 700: Insulation layer; 800: Flange structure; 900: Water collection tank; 910: Drain pipe.

[0045] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0046] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0047] Direct air capture (DAC) is a technology that captures carbon dioxide (CO2) from the atmosphere. By directly capturing CO2 from the air rather than other CO2 emission sources, it can effectively reduce atmospheric CO2 concentration and mitigate the greenhouse effect. As a typical negative carbon technology that can effectively promote the achievement of carbon neutrality goals, the application prospects of DAC technology have been widely recognized by the academic and industrial communities both domestically and internationally.

[0048] DAC technology is mainly divided into two categories: liquid absorption and solid adsorption. Among them, solid temperature-switching adsorption DAC technology is relatively mature. Production efficiency and energy consumption are two key parameters for evaluating the performance of solid adsorption DAC devices. Among these, the efficient mass and heat transfer between the gas and solid two-phase media in the gas-solid contactor (or reactor) is one of the factors that has the greatest impact on the performance of the DAC device.

[0049] During the adsorption phase of the gas-solid contactor, the adsorbent needs to be in full contact with the incoming air to reach saturated or near-saturated adsorption more quickly. During the desorption phase, the adsorbent needs to be in efficient contact with high-temperature gas (water vapor or CO2) or a heat exchange surface for heat transfer and temperature rise to achieve rapid desorption. This rapid adsorption-desorption process helps the DAC device achieve higher production efficiency and directly affects the overall energy consumption (electricity and heat) of the DAC device.

[0050] Furthermore, during the operation of the DAC device, the pressure drop of the gas passing through the adsorbent bed should be minimized, as this is closely related to the device's power consumption. The adsorbent bed should also maintain a uniform temperature distribution as much as possible to avoid localized hot spots, which could impair the adsorbent's lifespan.

[0051] Common solid temperature swing adsorption (DAC) devices typically employ two types of gas-solid contactors: fixed beds and honeycomb packed beds. Fixed beds tend to generate high bed pressure drops, especially at high gas flow rates. Therefore, larger particles must be used, typically with a diameter of 1 mm or more. However, large particle size significantly increases the mass transfer resistance of the gas within the pores of the particles, which is detrimental to achieving rapid CO2 adsorption.

[0052] Furthermore, large particle size reduces the heating and desorption rates as well as the cooling rate. Uneven airflow distribution also leads to uneven temperature distribution within the bed during adsorption and desorption, which reduces the CO2 adsorption capacity of the bed to some extent and prolongs the time required for the adsorption and desorption stages. In honeycomb packed beds, effective CO2 adsorption components are typically sprayed or impregnated onto the surface of the honeycomb-shaped inert packing support structure. Because the adsorption layer thickness is generally less than 1 mm and the gas flow area is large, the gas mass transfer rate is faster and the bed resistance drop is smaller.

[0053] However, due to the low content of effective adsorbent in the honeycomb packing bed (generally less than 10%), a large amount of inert matrix material needs to be continuously heated and cooled during the operation of the DAC device, which is not conducive to reducing the energy consumption per unit of CO2 capture.

[0054] The purpose of this application is to address the shortcomings of existing gas-solid contactors (DAC contactors) in direct carbon dioxide capture devices (DCC) by proposing a novel DCC contactor. Unlike the fixed-bed and honeycomb-filled-bed contactors used in conventional DCC devices, the DCC contactor proposed in this application employs a gas-solid fluidized bed, which uses micron-sized adsorbent particles with smaller particle sizes and larger specific surface areas. During adsorption and desorption at elevated temperatures, as the gas flows upward through the adsorbent particle bed, the particles are suspended in the gas flow. At this point, the particle powder exhibits properties very close to those of a liquid, such as buoyancy, and can be easily moved in and out of the reactor on a large scale. This achieves a so-called fluidized state.

[0055] In a fluidized bed, adsorbent particles with a diameter much smaller than those in a fixed bed can be used, resulting in a larger mass and heat transfer interface between the gas and solid phases. Furthermore, since the particles are always in a strong mixing process, the mass and heat transfer efficiency between the gas and solid phases is more efficient. This is beneficial for significantly shortening the time required for DAC adsorption and desorption operations and greatly improving the production efficiency of DAC devices.

[0056] During fluidized bed operation, the pressure drop of the granular bed is only related to the particle content and bed height. Therefore, the pressure drop of a fluidized bed with the same material height can be much lower than that of a fixed bed with the same particle size. Due to the strong particle mixing effect in the fluidized bed, the temperature distribution inside the bed is very uniform, and hot spots will not appear in the bed. This helps to avoid hot spots and extend the service life of the adsorbent.

[0057] The following provides a detailed description of the specific structure and various possible implementation methods of the gas-solid contactor for directly capturing carbon dioxide from the air.

[0058] Figure 1 This is a schematic diagram of the structure of a gas-solid contactor for directly capturing carbon dioxide from the air, provided in an embodiment of this application. Figure 2 This is a schematic diagram of the gas pre-distributor provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of the gas distribution plate provided in an embodiment of this application. Figure 4 This is a schematic diagram of the structure of the top cover and base provided in the embodiments of this application. Figure 5 This is a schematic diagram of the vessel wall insulation layer structure provided in the embodiments of this application. Figure 6 This is a schematic diagram of the standardized module structure provided in the embodiments of this application. Figure 7 This is a schematic diagram of a structure in which multiple modules are stacked vertically, as provided in an embodiment of this application.

[0059] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 as well as Figure 7 This application discloses a gas-solid contactor for directly capturing carbon dioxide from air, mainly comprising a fluidized bed container 100, a gas pre-distributor 200, a gas distributor 300, an adsorbent bed 400, a top cover 500, and a base 600. The gas pre-distributor 200 is located inside the fluidized bed container 100 and communicates with a gas inlet 110. The gas distributor 300 is located inside the fluidized bed container 100 and above the gas pre-distributor 200. The adsorbent bed 400 is located inside the fluidized bed container 100 and between the gas distributor 300 and the gas outlet 120. The top and bottom of the fluidized bed container 100 are respectively provided with an interconnectable top cover 500 and a base 600, allowing multiple fluidized bed containers 100 to be vertically stacked via the top cover 500 and the base 600. A water collection trough 900 is provided on the base 600, and the water collection trough 900 is connected to a drain pipe 910 that penetrates the base 600.

[0060] In this embodiment, the application mainly includes a fluidized bed container 100, a gas pre-distributor 200, a gas distributor 300, and an adsorbent bed 400. The gas pre-distributor 200 is located below the gas distributor 300 and is used to distribute the incoming gas in stages. Compared to related technologies that use a single distribution device or a simple air inlet structure, this allows for a more uniform gas distribution across the bed cross-section, ensuring sufficient contact between the gas and the adsorbent particles, thereby improving the carbon dioxide capture efficiency.

[0061] Because the adsorbent bed 400 uses micron-sized adsorbent particles and operates in a fluidized state, the fluidized bed can maintain a relatively low bed pressure drop when the gas flow rate is high. Furthermore, due to the vigorous mixing of the particles, the bed temperature distribution is very uniform, thus avoiding adsorbent failure caused by localized overheating. This extends the adsorbent's service life and ensures the stable operation of the device.

[0062] Because the fluidized bed container 100 has an interconnectable top cover 500 and a base 600 at its top and bottom, respectively, multiple containers can be stacked vertically. This modular design allows for flexible addition of processing units as needed to expand the processing scale, significantly saving floor space and reducing the cost of large-scale deployment, thus facilitating the industrial-scale application of the device. This achieves high efficiency, stability, and modular expansion of the carbon dioxide capture device, significantly improving its technical and economic efficiency.

[0063] Through the above structural design, the gas-solid contactor for directly capturing carbon dioxide from the air in this application achieves higher mass and heat transfer efficiency, lower operating energy consumption, more uniform temperature distribution, and better scalability than the prior art.

[0064] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 2 and Figure 6 The gas pre-distributor 200 adopts a dendritic structure, including a main gas pipe 210 connected to the gas inlet 110 and multiple gas branch pipes 220 connected to the main gas pipe 210. Each gas branch pipe 220 is distributed at intervals along the length of the main gas pipe 210, and its end extends toward the inner wall of the fluidized bed container 100.

[0065] The purpose of setting up the gas pre-distributor 200 is to initially and uniformly distribute the incoming gas to avoid uneven initial distribution when the gas enters and passes through the gas distributor 300, thereby creating good intake conditions for the gas distributor 300. In order to effectively reduce the power consumption of the entire system, the pressure drop of the gas pre-distributor 200 is controlled within 500 Pa.

[0066] Since the dendritic distribution structure is a commonly used airflow distribution structure in industry, it has good airflow uniformity, high structural reliability and simple manufacturing process, which helps to improve the uniform distribution effect of the gas pre-distributor 200 on the initial airflow, while ensuring the structural stability of the gas pre-distributor 200 in long-term operation and effectively controlling the manufacturing cost of the gas-solid contactor.

[0067] This dendritic structure achieves airflow distribution through a staged gas distribution method. When carbon dioxide-containing air enters the main gas pipe 210 from the gas inlet 110, it is diverted to various gas branch pipes 220. The ends of these branch pipes extend towards the container wall, guiding the airflow to the edge region of the container. This effectively eliminates the dead zone at the bottom of the bed, creating favorable conditions for uniform gas distribution in the upper gas distributor 300. This achieves effective dispersion and guidance of the initial airflow, ensuring a uniform distribution of airflow across the bed cross-section, thus providing crucial support for the formation of a stable fluidized state.

[0068] In this embodiment, a water collection tank 900 is provided on the base 600, and a drain pipe 910 is connected to the water collection tank 900 through the base 600. A drain valve is provided on the drain pipe 910, and the drain valve is electrically connected to the control unit.

[0069] Since the water collection tank 900 and the drain pipe 910 constitute a liquid water collection and discharge structure, it has high drainage efficiency, good structural stability and low manufacturing cost, which is conducive to timely removal of water accumulated inside the device, while ensuring the long-term reliable operation of the drainage system and effectively controlling the manufacturing cost of the device.

[0070] Because the water collection tank 900 is located on the upper surface of the base 600, and the drain pipe 910 works in conjunction with the drain valve, when condensate or other liquid water is generated during the operation of the device, the water will collect in the water collection tank 900 by gravity. When the liquid level reaches a preset height or the predetermined drainage time is reached, the control unit will send an opening command to the drain valve, and the accumulated liquid will be automatically discharged from the outside of the device through the drain pipe 910. After drainage is completed, the control unit will send a closing command to the drain valve, thereby preventing backflow of external gas and ensuring the sealing and operational stability of the device. This achieves the function of automatically removing water accumulated inside the device, and also achieves the purpose of protecting the adsorbent and extending the life of the device.

[0071] As an optional implementation, in some embodiments, the bottom of the water collection tank 900 is inclined, and its lowest point is connected to the inlet end of the drain pipe 910.

[0072] In this embodiment, the bottom of the water collection tank 900 is inclined, which allows the collected liquid to flow naturally to the inlet of the drain pipe 910 under gravity, thereby improving drainage efficiency and preventing liquid accumulation in the tank. Since the lowest point of the tank bottom is directly connected to the inlet of the drain pipe 910, it ensures that the liquid in the water collection tank 900 is completely drained, effectively preventing corrosion or bacterial growth caused by liquid accumulation in dead zones, thus further ensuring the hygienic operation and long-term reliability of the device.

[0073] As an optional implementation, in some embodiments, the diameter of the branch pipe 220 gradually decreases along the airflow direction, and the connection between each branch pipe and the main pipe adopts an arc transition.

[0074] In this embodiment, since the diameter of the gas branch pipe 220 gradually decreases along the airflow direction, this conforms to the pressure distribution law of airflow within the branch pipe, which helps maintain the momentum consistency of the airflow at the outlet of each branch pipe, thereby further improving the uniformity of airflow distribution. Because the connection between each branch pipe and the main pipe uses a rounded transition, local resistance loss can be effectively reduced, preventing eddies and energy loss in the airflow at this point, thus reducing the overall pressure drop of the gas pre-distributor 200, which helps reduce the overall operating energy consumption of the device.

[0075] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 3 and Figure 6 The gas distributor 300 includes a gas distribution plate 310 and a plurality of air holes 320 formed on the gas distribution plate 310. The gas distribution plate 310 is fixedly installed on the inner wall of the fluidized bed container 100.

[0076] The gas distribution plate 310, with uniformly distributed vents 320, is a key component in the fluidized bed. Its robust structure, precise airflow distribution, and controllable pressure drop facilitate the formation of a uniform and stable airflow across the entire cross-section of the adsorbent bed 400, ensuring high-quality fluidization. Furthermore, the gas distribution plate 310 boasts strong pressure resistance and a long service life, contributing to the long-term stable operation of the entire gas-solid contactor.

[0077] Because the gas distribution plate 310 is located above the gas pre-distributor 200 and fixed to the inner wall of the container, when the gas, after initial distribution by the pre-distributor, flows upward, it is forced through the pores 320 on the gas distribution plate 310. These uniformly distributed pores 320 can perform secondary distribution and rectification of the airflow, dividing the airflow into a large number of fine streams, thereby forming a dead-zone-free, uniformly velocity-field airflow distribution surface at the bottom of the adsorbent bed 400. In this way, the adsorbent particles can obtain uniform drag and be fluidized smoothly and consistently, effectively avoiding undesirable fluidization phenomena such as local dead zones or stagnation, ensuring sufficient contact between the gas and solid phases, thereby achieving efficient adsorption and desorption of carbon dioxide.

[0078] As an optional implementation, in some embodiments, the gas distribution plate 310 is a multilayer sintered metal filter plate or a powder metallurgy filter plate. The pressure drop of the gas distribution plate 310 is controlled between 0.4 and 2 kPa. In addition to requiring a low pressure drop, the gas distribution plate 310 should also have sufficient rigidity and mechanical strength to avoid excessive deformation or damage under alternating pressure loads during different operating stages such as adsorption, vacuum, and purging, thus ensuring the long-term reliability of the device.

[0079] In this embodiment, a multi-layer sintered metal filter plate or powder metallurgy filter plate is used as the gas distribution plate 310. This type of element is made of metal powder sintered at high temperature and has a large number of nano- and micro-sized, tortuous and interconnected pores inside, which can serve as a natural, high-performance, densely porous distribution plate. In this way, when gas passes through, it is further refined by these tiny pores, achieving an excellent gas distribution effect.

[0080] Because the gas distribution plate 310 employs the aforementioned porous or densely porous structure and strictly controls its pressure drop, it can minimize the energy loss of the gas passing through the distribution plate itself while ensuring uniform airflow distribution. This directly reduces the power consumption of the blower driving the gas flow, thereby facilitating low-energy operation of the carbon dioxide capture process.

[0081] Meanwhile, due to its sufficient rigidity, the gas distribution plate 310 can effectively withstand the static pressure of the adsorbent bed 400, as well as the huge pressure differential stress generated during vacuum and pressurized cyclic operation. This prevents the distribution plate from bending, deforming, or even cracking during long-term use, avoiding serious consequences such as uneven gas distribution and adsorbent leakage caused by damage to the distribution plate. Therefore, the gas distribution plate 310 not only ensures the efficient and stable operation of the gas-solid contactor in the initial stage, but also greatly improves the operational reliability and service life of the entire gas-solid contactor.

[0082] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 5 and Figure 6The fluidized bed container 100 has an insulation layer 700 on its inner wall. The insulation material used in the insulation layer 700 should have the lowest possible thermal conductivity and be able to withstand the periodic changes in temperature and pressure experienced by the fluidized bed container 100 during cyclic operations such as adsorption, vacuum, and heating desorption.

[0083] The insulation layer 700 is an effective thermal insulation measure to cope with internal temperature changes. It has good thermal insulation effect, compact structure and high reliability, which helps to form a temperature field inside the fluidized bed container 100 that is less affected by the external environment, providing a stable thermal environment for the adsorption and desorption processes. At the same time, it can significantly reduce ineffective heat loss during circulation operation, which helps to reduce the operating energy consumption of the entire carbon dioxide capture device.

[0084] Because the insulation layer 700 is directly applied to the inner surface of all fluidized bed containers 100 in contact with the process gas, when the gas-solid contactor introduces a heat medium during the high-temperature desorption stage, the insulation layer 700 effectively blocks heat transfer to the container wall, thereby reducing heat loss to the environment through the metal walls. When the device switches to the ambient temperature adsorption stage, the insulation layer 700 also blocks heat from the external environment, helping to maintain the optimal temperature required for adsorption.

[0085] In this way, the heat energy introduced into the gas-solid contactor can be used more concentratedly for the heating and desorption of the adsorbent, or more effectively maintain the low temperature of the adsorption bed, avoiding the additional energy burden caused by heat dissipation or heat absorption of the compensator wall, and improving the thermal efficiency of the entire system.

[0086] As an optional implementation, in some embodiments, the insulation material used for the insulation layer 700 is ceramic fiber or high-temperature resistant foam ceramic.

[0087] In this embodiment, ceramic fiber or high-temperature resistant foam ceramic is used as the material of the insulation layer 700. Such materials have extremely low thermal conductivity, excellent temperature resistance and good chemical stability, and can withstand repeated temperature rises and falls and pressure changes during the operation of the gas-solid contactor for a long time.

[0088] Because the insulation layer 700, composed of ceramic fiber or high-temperature resistant foam ceramic, possesses the aforementioned characteristics, it can form a highly efficient, reliable, and durable thermal barrier inside the fluidized bed container 100. This not only minimizes the aforementioned ineffective heat loss, achieving energy conservation and consumption reduction, but its stable physicochemical properties also ensure that the insulation layer 700 will not fail due to thermal shock or aging throughout the entire life cycle of the device, thereby guaranteeing the stability and reliability of the gas-solid contactor during long-term operation and helping to maintain the service life of the adsorbent.

[0089] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 4 and Figure 7 Both the top cover 500 and the base 600 are elliptical covers, and the top cover 500 is connected to the base 600 of the adjacent module via a flange 800.

[0090] Since both the top cover 500 and the base 600 adopt a standard elliptical shape, their load-bearing performance is excellent, effectively and evenly transmitting internal pressure to the entire container. This minimizes local stress concentration when subjected to pressure fluctuations during the cyclic operation of the fluidized bed container 100, significantly improving the structural integrity and operational safety of the fluidized bed container 100. Furthermore, this shape is a standard component in industry, facilitating procurement and manufacturing, and helping to control equipment costs.

[0091] The flange structure 800 on the top cover 500 and the base 600 provides a standardized and highly reliable mechanical connection interface for a single module. When multiple contactor modules need to be stacked vertically to expand processing capacity, a secure and sealed connection between the two pressure vessels can be easily achieved by fastening the flange of the upper module base 600 to the flange structure 800 of the lower module top cover 500.

[0092] Specifically, flange connections ensure the sealing of individual containers under vacuum and low-pressure operation, preventing gas leakage. They also provide a crucial technological foundation for modular scaling up of the device. This allows multiple modules to be quickly and precisely stacked into a single unit, like building blocks, with naturally interconnected flow channels between modules. This linearly increases the overall carbon dioxide capture capacity without significantly increasing the footprint. This design greatly enhances the flexibility of scalability and reduces the design and construction costs of large-scale systems.

[0093] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 , Figure 6 and Figure 7 The fluidized bed container 100 adopts a cylindrical structure.

[0094] Because cylindrical containers can evenly distribute loads across the entire shell when subjected to internal or external pressure, their stress performance is significantly superior to other geometries. Therefore, adopting this structure is beneficial for improving the structural stability and safety of the fluidized bed container 100 under vacuum and low-pressure operating conditions. Furthermore, as a standard industrial container form, the cylindrical structure has a mature manufacturing process, is easy to procure and process, and helps control equipment manufacturing costs.

[0095] As an optional implementation, in some embodiments, the fluidized bed container 100 is a metal or non-metal container with a certain compressive strength, and the inner wall of the container is provided with a heat-insulating material with good thermal insulation effect. The main purpose of this design is to avoid the continuous heating and cooling of the structure of the fluidized bed container 100 during the gas-solid contactor circulation operation, thereby avoiding additional energy consumption.

[0096] Because the fluidized bed container 100 is made of materials with sufficient compressive strength, it can withstand the internal pressure changes and external atmospheric pressure generated during the four-stage cyclic operation of adsorption, vacuum purification, heating desorption and vacuum purging, ensuring the safety and structural reliability of the equipment under long-term alternating loads.

[0097] By adopting a design philosophy that avoids the container structure itself from participating in thermal cycling, and by incorporating an insulation layer 700 on the inner wall of the container, the wall temperature of the fluidized bed container 100 can be kept relatively stable. This greatly reduces ineffective heat transfer caused by the temperature difference between the container wall and the internal adsorbent bed 400.

[0098] As an alternative implementation, in some embodiments, the adsorbent bed 400 comprises micron-sized carbon dioxide adsorbent particles.

[0099] Because it uses micron-sized adsorbent particles, it has a much larger specific surface area compared to the large-diameter (millimeter-sized) particles used in traditional fixed or moving beds. When these particles are fluidized in the fluidized bed, they can provide an extremely sufficient contact interface for the gas and solid phases, thereby significantly improving the capture and desorption rates of carbon dioxide.

[0100] Specifically, the application of micron-sized particles solves the internal mass transfer resistance problem faced by large particles. During the adsorption stage, low-concentration CO2 molecules in the air can diffuse to the active sites inside the particles more quickly.

[0101] During the desorption phase, adsorbed CO2 molecules can also be released from the pores more rapidly, significantly shortening the time required for a complete adsorption-desorption cycle. Simultaneously, micron-sized particles exhibit a faster thermal response in fluidized states, allowing for rapid and uniform heating during the heating-desorption phase and rapid cooling in the subsequent cooling phase, reducing ineffective heating and cooling time and effectively lowering the unit operating energy consumption of the device. The selection of particle size is one of the core key technical features for achieving the high efficiency and low energy consumption operation of this application.

[0102] The apparent gas velocity of the adsorbent bed 400 is recommended to be controlled within the range of 0.3~1.2 m / s, and it should be placed in the turbulent fluidization operating region. The apparent gas velocity is defined as the ratio of the gas volumetric flow rate under operating conditions to the cross-sectional flow area of ​​the fluidized bed container 100.

[0103] By precisely controlling the apparent gas velocity within the range of 0.3–1.2 m / s and ensuring the bed is in a turbulent fluidized state, the micron-sized adsorbent particles within the bed generate intense, irregular vortex motion. This motion greatly enhances the interaction and renewal frequency between the gas and solid particles, thereby creating a huge mass and heat transfer interface and extremely high transfer rates between the gas and solid phases.

[0104] Specifically, the selection of the gas velocity range ensures, on the one hand, that the adsorbent particles can be fully fluidized, avoiding local dead zones or stratification at lower gas velocities, thus guaranteeing that all adsorbents can effectively participate in the CO2 capture process. On the other hand, it limits the gas velocity to a reasonable upper limit, avoiding excessively high gas velocities that lead to severe particle entrainment, accelerated equipment wear, and unnecessary increases in energy consumption.

[0105] Determining the turbulent fluidization operating domain is key to achieving high mass and heat transfer efficiency. It directly leads to a significant increase in CO2 adsorption and desorption rates, thereby significantly shortening the time required for each operating cycle and improving the unit time processing capacity and production efficiency of the DAC device.

[0106] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 1 The gas outlet 120 of the fluidized bed container 100 should be located above the surface of the adsorbent bed 400. Its vertical height from the bottom gas distribution plate 310 is designed to be 2 to 6 times the height of the static adsorbent bed.

[0107] By positioning the gas outlet 120 at a sufficient height away from the bed surface, ample settling space is provided to suppress the fine particles entrained by the airflow after leaving the bed. This allows most of the entrained adsorbent particles to settle back into the bed due to their own gravity, thereby achieving effective separation of the gas and solid phases.

[0108] Specifically, this height design (2 to 6 times the static bed height) is based on a balance between the operating characteristics of the fluidized bed and the particle entrainment pattern. Too low a height could result in a large number of adsorbent particles being directly carried into the outlet pipe by the airflow, causing severe adsorbent loss and blockage of subsequent systems. Conversely, an excessively high design would unnecessarily increase the equipment's manufacturing cost and floor space.

[0109] This height range effectively ensures that, within the expected operating gas velocity range, adsorbent entrainment loss can be controlled to an acceptablely low level, while maintaining stable bed stock levels. This not only protects downstream process equipment and avoids adsorbent waste, but also fundamentally guarantees that the DAC contactor can achieve long-term, stable, and continuous reliable operation.

[0110] As an alternative implementation, in some embodiments, the gas outlet 120 is connected to a vacuum pump.

[0111] Because the gas outlet 120 is connected to a vacuum pump, the fluidized bed container 100 can actively reduce the absolute pressure inside the system through this vacuum pump, providing the necessary conditions for achieving an efficient desorption process and obtaining high-purity carbon dioxide products. At the same time, using a vacuum pump as a pressure control device is a mature technology in industry, offering precise control and rapid response, which helps improve the operational reliability and stability of the entire system.

[0112] A vacuum pump is also connected to drain pipe 910. During vacuum purification or purging, when liquid water collected in collection tank 900 needs to be drained, the negative pressure environment provided by the vacuum pump can actively and quickly extract the accumulated liquid, overcoming the problems of incomplete drainage and slow speed that may occur when relying solely on gravity drainage. This active drainage mechanism ensures that the drainage system can still operate efficiently and reliably when the device is under negative pressure, avoiding the adverse effects of accumulated liquid on the fluidization quality of the adsorbent and the operational stability of the device, further improving the adaptability and reliability of the device under complex operating conditions.

[0113] This application discloses a gas-solid contactor control method for directly capturing carbon dioxide from the air, comprising a plurality of gas-solid contactors for directly capturing carbon dioxide from the air, and a control unit electrically connected to a fluidized bed container 100. The control unit is configured to control the fluidized bed container 100 to sequentially perform adsorption, vacuum purification, heating desorption and vacuum purging operations.

[0114] The fluidized bed vessel 100 needs to perform four operation steps in sequence: adsorption, vacuum purification, heating desorption, and vacuum purging.

[0115] Adsorption Steps: The control unit starts the blower, introducing ambient air into the fluidized bed container 100 through the gas inlet 110. The air first flows through the gas pre-distributor 200 for initial distribution, and then through the gas distribution plate 310 for secondary uniform distribution, thus uniformly entering the adsorbent bed 400. In the turbulent fluidized bed, CO2 gas in the air is efficiently adsorbed by micron-sized adsorbent particles. After CO2 capture is complete, the carbon dioxide-lean air rising out of the bed is discharged from the contactor through the gas outlet.

[0116] Vacuum purification step: When the adsorbent bed 400 reaches or is close to adsorption saturation, the control unit closes the gas inlet 110 and starts the vacuum pump connected to the gas outlet 120. This reduces the absolute pressure inside the fluidized bed container 100 to 0.4–0.9 atmospheres. The purpose of this stage is to remove residual nitrogen, oxygen, and other non-target components from the container, thereby significantly improving the purity of the subsequently collected CO2 product gas.

[0117] Heating and desorption step: The control unit closes the gas outlet 120 and instead introduces a high-temperature medium, preferably high-temperature water vapor or high-temperature CO2 gas, through the gas inlet 110. The hot medium uniformly and rapidly heats the fluidized adsorbent particles to a preset desorption temperature (e.g., 100~150℃) and maintains it for a period of time. Under these conditions, the CO2 adsorbed in the pores of the adsorbent particles is fully released.

[0118] Vacuum purging procedure: The control unit shuts off the heat medium supply and restarts gas outlet 120 and the connected vacuum pump. At this time, gas outlet 120 is connected to the downstream CO2 compression and liquefaction unit. Under vacuum, the high-concentration CO2 gas generated by desorption is continuously extracted and transported to the compression and liquefaction unit until the absolute pressure inside the fluidized bed container 100 drops back to 0.4~0.9 atmospheres, thus completing one complete operating cycle.

[0119] In the operation of this application, since the concentration of CO2 in the air is only about 0.04%, the adsorption stage usually takes a long time, which is several times longer than the total time of the other three stages (vacuum removal, steam heating desorption, and vacuum purging).

[0120] To improve the overall production efficiency of the equipment, the control unit accurately calculates the ratio of the adsorption stage to the total time of the last three stages based on the characteristics of the adsorbent used, and coordinates the operation sequence of multiple gas-solid contactors based on this ratio.

[0121] Specifically, control methods also include:

[0122] Multiple gas-solid contactors are controlled to operate in an alternating sequence, ensuring that at any given time, at least N gas-solid contactors are in the adsorption stage, while M gas-solid contactors are in the non-adsorption stage, which consists of vacuum purification, heating desorption, and vacuum purging. Here, N and M are both positive integers, and N≥1, M≥1.

[0123] When the first gas-solid contactor that has completed the adsorption stage is detected, the gas-solid contactor is controlled to switch from the adsorption stage to the non-adsorption stage, and simultaneously the gas-solid contactor that has completed the non-adsorption stage first is controlled to switch from the non-adsorption stage to the adsorption stage.

[0124] As an optional implementation, in some embodiments, the ratio of the number N of contactors in the adsorption phase to the number M of contactors in the non-adsorption phase is determined based on the ratio of the adsorption phase time of a single contactor to the total non-adsorption phase time of a single contactor.

[0125] As an optional implementation, in some embodiments, the ratio is determined by the following formula: N ≈ K×M, where K is the ratio of the adsorption phase time of a single contactor to the total non-adsorption phase time. When K is a decimal, the result of K×M is rounded up to determine the value of N.

[0126] This optimized operating strategy ensures that most contactors are in a highly efficient CO2 capture state at all times, maximizing the overall utilization of the adsorption unit.

[0127] Specifically, by coordinating the operation between contactors, the originally serial adsorption and regeneration process is transformed into parallel processing, realizing the semi-continuous operation of the carbon dioxide capture process. This significantly improves the CO2 capture rate per unit time while maintaining the integrity and independence of each contactor's operation, providing key technical support for the efficient and stable operation of large-scale DAC devices.

[0128] A modular stacked structure for direct capture of carbon dioxide from the air includes: standard modules of multiple gas-solid contactors for direct capture of carbon dioxide from the air, wherein the standard modules are connected to the bottom flange structures 800 of adjacent modules via a top flange structure 800.

[0129] As an optional implementation, in some embodiments, see [link to relevant documentation]. Figure 6 and Figure 7 The fluidized bed container 100 is designed and manufactured as a standard modular unit. When the carbon dioxide capture capacity needs to be increased, multiple standard modules can be stacked vertically together to form an integrated treatment system.

[0130] Thanks to its standardized modular design, each contactor module has identical structural dimensions and interface specifications, making the connection and assembly between modules simple and reliable. At the same time, the modular design facilitates industrial mass production, effectively reducing the production cost of individual modules through large-scale manufacturing.

[0131] Thanks to the vertically stacked integration method, multiple modules are securely combined together through standardized interfaces (such as flange connections) at their top and bottom. This arrangement allows for increased processing capacity by vertical stacking, rather than horizontal expansion, enabling the scaling up of the unit.

[0132] Specifically, this modular, vertically integrated design offers several significant advantages. First, it greatly reduces the footprint of the DAC system, enabling large-scale CO2 capture facilities to be deployed in areas with limited land resources, thus improving project feasibility. Second, the design provides the unit with extremely high scalability flexibility; production capacity can be linearly and precisely adjusted according to actual needs by adding or removing modules, avoiding the radical redesign often required when expanding traditional facilities.

[0133] In addition, standardized modules greatly facilitate maintenance and component replacement. When a single module needs to be repaired, it can be handled specifically without affecting the overall structure of the entire system, significantly improving the maintainability and operational efficiency of the device.

[0134] To accurately evaluate the technical effectiveness of this application under laboratory conditions, two small-scale DAC evaluation devices were constructed for comparative testing, employing a fixed-bed contactor and the gas-solid contactor of this application. The contactor has an inner diameter of 0.2 m and a total height of approximately 0.56 m, and is made of a 5 mm thick stainless steel housing.

[0135] The adsorbent used was a certain type of resin-based solid amine adsorbent with an average particle size of 0.602 mm. The same mass of adsorbent was used in all experimental tests, and the corresponding static packing height of the bed was 0.1 m.

[0136] Table 1. Comparison of performance of fixed-bed and fluidized-bed DAC experimental setups (U=0.6m / s)

[0137]

[0138] Table 2 Comparison of performance of fixed-bed and fluidized-bed DAC experimental setups (U=0.4m / s)

[0139]

[0140] As shown in Table 1, during the adsorption stage, when the apparent gas velocity (total air volumetric flow rate / bed cross-sectional area) U = 0.6 m / s, the pressure drop of the fixed-bed contactor is 11.5 kPa, while that of the gas-solid contactor is only 0.41 kPa. Even with the pressure drop from the bottom gas distributor, the total pressure drop is only 1.56 kPa. At an even lower apparent gas velocity of U = 0.4 m / s, the pressure drop of the fixed bed is 6.9 kPa, while the total pressure drop of the fluidized bed is only 0.92 kPa (Table 2). This significant reduction in the total pressure drop of the contactor helps to save on the power consumption and operating costs of the DAC device.

[0141] Because fluidized beds have higher gas-solid contact efficiency, CO2 gas in the air can contact and transfer mass with adsorbent particles more efficiently during the adsorption stage. Therefore, the adsorption time is significantly reduced compared to fixed beds. When U=0.6m / s, the time required for the adsorbent to reach 80% saturation (i.e., 80% of the saturated adsorption capacity) is reduced from 131.5min to 112.2min. When U=0.4m / s, the adsorption time is reduced from 201min to 168.3min, as shown in Tables 1 and 2.

[0142] During the desorption stage, because water vapor can achieve more efficient contact heat transfer with adsorbent particles in the gas-solid contactor, the desorption time (the total time of the three stages of vacuum removal, steam heating desorption, and vacuum purging) is also reduced to a certain extent. Under the same desorption operation process, the desorption time of the gas-solid contactor is reduced from 30 min to 26 min (Tables 1 and 2).

[0143] When the gas-solid contactor is insulated with 30mm thick high-efficiency aerosol insulation material, the desorption time can be further reduced to 24 minutes, as there is no need to heat the external steel contactor container. This reduction in adsorption and desorption time improves the production efficiency of the DAC device and reduces the heat consumption required for CO2 capture per unit mass.

[0144] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for controlling a gas-solid contactor for direct capture of carbon dioxide from air, characterized in that, It includes multiple gas-solid contactors that directly capture carbon dioxide from the air, and a control unit that is electrically connected to the fluidized bed container; The gas-solid contactor includes: A fluidized bed container, the fluidized bed container including a gas inlet and a gas outlet formed on the container wall, the gas inlet being located below the gas outlet; A gas pre-distributor is located inside the fluidized bed container and is connected to the gas inlet; A gas distributor is disposed inside the fluidized bed container and located above the gas pre-distributor; An adsorbent bed is disposed inside the fluidized bed container and located between the gas distributor and the gas outlet; The fluidized bed container is provided with a top cover and a base that can be connected to each other at the top and bottom, and multiple fluidized bed containers can be stacked vertically through the top cover and the base; The base is provided with a water collection tank, and the water collection tank is connected to a drain pipe that passes through the base; The gas-solid contactor control method includes the following steps: Adsorption step: Open the gas inlet and introduce air into the fluidized bed container so that CO2 in the air comes into contact with and is adsorbed by the adsorbent particles in the fluidized state. Vacuum purification step: Close the gas inlet, turn on the vacuum pump connected to the gas outlet, and reduce the absolute pressure inside the fluidized bed container to 0.4~0.9 atmospheres to remove residual air components; Heating desorption step: Close the gas outlet and introduce a high-temperature medium through the gas inlet to raise the temperature of the adsorbent particles to the desorption temperature, thereby desorbing the adsorbed CO2 gas; Vacuum purging step: Close the gas inlet, turn on the gas outlet and the vacuum pump connected to the gas outlet, extract the desorbed CO2 gas and transport it to the subsequent processing unit until the absolute pressure in the fluidized bed container drops to 0.4~0.9 atmospheres; turn on the vacuum pump connected to the drain pipe to discharge the condensate produced by the water vapor condensation in the heating and desorption step; The gas-solid contactor cyclically performs the adsorption step, the vacuum impurity removal step, the heating desorption step, and the vacuum purging step; The vacuum purification step, the heating desorption step, and the vacuum purging step are non-adsorption steps. Multiple gas-solid contactors are controlled to operate in an interleaved sequence, such that at any given time, at least N gas-solid contactors are in the adsorption step, while M gas-solid contactors are in the non-adsorption step; where N and M are both positive integers, and N≥1, M≥1. When the first gas-solid contactor that has completed the adsorption step is detected, the gas-solid contactor is controlled to switch from the adsorption step to the non-adsorption step, and simultaneously the gas-solid contactor that has completed the non-adsorption step first is controlled to switch from the non-adsorption step to the adsorption step. The ratio of the number of contactors N in the adsorption step to the number of contactors M in the non-adsorption step is determined by the following formula: N ≈ K×M Where K is the ratio of the adsorption step time to the total non-adsorption step time of a single gas-solid contactor. When K is a decimal, the result of K×M is rounded up to determine the value of N.

2. The gas-solid contactor control method for directly capturing carbon dioxide from air according to claim 1, characterized in that, The gas pre-distributor includes a main gas pipe and several branch gas pipes connected to the main gas pipe, and the main gas pipe is connected to the gas inlet.

3. The gas-solid contactor control method for directly capturing carbon dioxide from air according to claim 1, characterized in that, The gas distributor includes a gas distribution plate and a plurality of gas holes formed on the gas distribution plate, and the gas distribution plate is installed on the inner wall of the fluidized bed container.

4. The gas-solid contactor control method for directly capturing carbon dioxide from air according to claim 1, characterized in that, The inner wall of the fluidized bed container is provided with a heat insulation layer.

5. The gas-solid contactor control method for directly capturing carbon dioxide from air according to claim 1, characterized in that, Both the top cover and the base are provided with flange structures; When multiple fluidized bed containers are stacked, the top cover and the base of adjacent fluidized bed containers are connected by the flange structure.

6. The gas-solid contactor control method for directly capturing carbon dioxide from air according to claim 1, characterized in that, The adsorbent bed comprises micron-sized adsorbent particles. During adsorption, the bed is in a fluidized state, with an apparent gas velocity ranging from 0.3 to 1.2 m / s.

7. The gas-solid contactor control method for directly capturing carbon dioxide from air according to claim 1, characterized in that, include: Multiple standard modules of the gas-solid contactor that directly captures carbon dioxide from the air are vertically stacked via flange connections.

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