Carbon dioxide direct air trap, trapping system and trapping method

Abstract

The invention discloses a carbon dioxide direct air trap, a trapping system and a trapping method. A direct air catcher for carbon dioxide comprises a barrel, an electric heater, an electric heating element, a valve plate and a valve rod. An electric heating plate in the trap is used as a partition plate to separate the internal space of a barrel, so that air flows along a one-way channel from an air inlet to an air outlet in the limited space of the barrel, residual air in the barrel before the desorption step is discharged by using the pushing force of a valve plate, and carbon dioxide remaining in the barrel after desorption is discharged. The carbon dioxide obtained through the method is high in purity, a vacuum pump needed by traditional vacuum desorption can be omitted, and the subsequent separation problem caused by water vapor purging desorption is also avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide capture, and in particular relates to a carbon dioxide direct air capture device, a capture system and a capture method. Background Art

[0002] Direct air capture (DAC) technology is an emerging negative carbon emission technology that can directly capture and store or utilize carbon dioxide in the air without geographical restrictions. The capture point and the storage or utilization point can be placed in one place, thereby reducing transportation costs. At the same time, it can solve the emission problems of many carbon dioxide distribution sources such as transportation and construction industries. DAC technology can be divided into two categories: liquid DAC technology and solid DAC technology. Among them, solid-state DAC technology has the advantages of low regeneration temperature and fast adsorption rate, but the adsorption effect is greatly affected by the thermal stability of the adsorbent, and the adsorbent needs to be replaced regularly to ensure a good adsorption effect.

[0003] CN 114504924 A discloses a modular direct air carbon dioxide capture device and a process intensification method, comprising a pretreatment module, a cyclic adsorption thermal desorption module and a storage module, wherein the cyclic adsorption thermal desorption module is used to adsorb carbon dioxide in the air through a two- or three-pass air adsorption loop, and thermally desorb the adsorbed carbon dioxide. The adsorption is carried out in a multi-pass adsorption return mode, which reduces the occupied area, but the contact area between the air and the solid adsorbent in each pass is small, and the amount of carbon dioxide captured is also small.

[0004] CN 115055029 A discloses a carbon dioxide collector, including a shell, a radiation tube and a solid adsorbent. The radiation tube is connected to the shell, and the radiation tube is connected to the heat source. The solid adsorbent is filled between the inner wall of the shell and the outer wall of the radiation tube. The solid adsorbent is used to adsorb carbon dioxide in the conversion gas. A radiation sheet is arranged on the radiation tube, which increases the area of ​​heat radiated by the radiation tube to the solid adsorbent, which not only improves the efficiency of heat radiation from the heat source gas to the solid adsorbent, but also makes the solid adsorbent heated more evenly, thereby improving the decomposition efficiency. However, when the heat source heats the adsorbent through the radiation tube to achieve regeneration, the air retained in the adsorbent gap will leave the collector together with the desorbed carbon dioxide gas, affecting the purity of the carbon dioxide.

[0005] WO2020113281 A1 discloses an adsorption and desorption device, including a tank body, a fan, a vacuum pump, and a solid adsorption unit in the tank body. The solid adsorption unit is rolled from a substrate coated with a composite coating. The substrate is rolled in multiple layers with a heating element as the center. The heating element is used to heat the solid adsorbent, and a vacuum pump is used to form a negative pressure environment in the tank to achieve purging and carbon dioxide desorption. However, when the vacuum pump is used to extract the residual air in the tank, a part of the air will remain in the tank, affecting the purity of the carbon dioxide obtained by desorption, and the heating element heats the solid adsorbent from the inside to the outside, resulting in uneven heating. Summary of the invention

[0006] In view of the problems existing in the prior art, an object of the present invention is to provide a carbon dioxide direct air capture device, a capture system and a capture method.

[0007] A first aspect of the present invention provides a carbon dioxide direct air collector, comprising: a cylinder, an electric heater, an electric heating element, a valve plate, and a valve stem; The top of the cylinder is provided with a top plate, which is provided with one or more valve stem holes for the valve stem to move up and down; the upper part of the cylinder is provided with an air outlet, the lower part of the cylinder is provided with a carbon dioxide outlet, and the side wall of the cylinder is provided with an air inlet; the bottom of the cylinder is connected to the electric heater through a flange; the side wall, top plate and flange of the cylinder are all provided with an inner insulation layer of a certain thickness; The electric heating element is arranged inside the cylinder parallel to the central axis of the cylinder, and is arranged to form a one-way channel from the air inlet end to the air outlet end, and the channel length is greater than the longest distance between two points on the cross section of the cylinder; the one-way channel is preferably a spiral one-way channel or a zigzag one-way channel; The bottom end of the electric heating element is connected to the top of the electric heater, and the top end is connected to the inner insulation layer of the top plate; a solid adsorbent of a certain thickness is coated on the surface of the electric heating element; the electric heating element is preferably an electric heating plate; the top and bottom ends of the electric heating element are along the axial direction of the cylinder; The electric heating element can be arranged in a spiral-like manner, rotating along a certain shape with the central axis of the cylinder as the center and gradually moving away from the center. The rotating shape can be circular, rectangular or triangular, preferably circular and rectangular, and the one-way channel formed is spiral-like; the electric heating element can also be arranged in a parallel staggered manner to form a zigzag one-way channel, one end of which is parallel to the length direction of the electric heating element and is fixedly connected to the corresponding inner wall of the cylinder, and the other end maintains a certain gap with the inner wall of the opposite cylinder, and the length of the gap is 20~500mm, preferably 50~300mm; The valve plate is connected to the valve stem, the valve plate covers the entire cross section of the channel (wherein the cross section does not include the wall thickness of the channel formed by the electric heating element), the valve stem is arranged parallel to the central axis of the cylinder, and the valve stem drives the valve plate to move up and down along the inner wall of the channel; In the collector of the present invention, the cross-section of the cylinder can be circular or polygonal, preferably circular or square; the top plate and side walls of the cylinder have a certain wall thickness and can withstand a certain negative pressure; the outer periphery of the top plate of the cylinder is sealed and welded to the upper edge of the side wall of the cylinder, and a flange is provided at the lower end of the cylinder, and the flange is sealed and welded to the side wall of the cylinder; the thickness of the inner insulation layer arranged on the side wall of the cylinder, the top plate and the lower flange is determined according to the heating temperature and the performance of the insulation material, and is generally 20~100mm.

[0008] In the collector of the present invention, the electric heater is a detachable structure, and the temperature of the electric heating element can be adjusted through the control box; the electric heating plate can be a large piece or several small pieces, determined according to the arrangement method; the gas in the cylinder moves along the one-way channel formed by the electric heating element, and the width of the one-way channel perpendicular to the gas flow direction is 20~500mm, preferably 50~300mm.

[0009] In the trap of the present invention, all edges of the valve plate are uniformly coated with a layer of sealing material, and the sealing material is preferably graphite, tetrafluoroethylene or carbon fiber material; the thickness of the valve plate is not less than 10mm, and the diameter of the valve stem is not less than 50mm; the valve plate is fixedly connected to the valve stem, and the number of valve stems can be one or more; the valve stem moves up and down along the central axis of the cylinder under the action of air pressure or hydraulic drive. The number of the valve stem holes in the top plate is the same as the number of the valve stems, and a packing seal is used between the valve stem holes and the valve stem.

[0010] In the collector of the present invention, the air inlet, air outlet and carbon dioxide outlet are all provided with corresponding valves and pipelines, and the valves are all switch valves; the material of the cylinder and its flange, valve stem and valve plate is stainless steel; the material of the inner insulation layer is industrial general insulation cotton, preferably aluminum silicate or ceramic fiber.

[0011] In the collector of the present invention, the solid adsorbent is preferably a solid amine adsorbent or a MOFs adsorbent. The solid adsorbent is evenly coated on the outer surface of the electric heating element by an adhesive, and the outer surface after coating should be flat and sufficiently smooth.

[0012] The second aspect of the present invention provides a carbon dioxide direct air capture system, which includes the above-mentioned carbon dioxide direct air capture device, pretreatment equipment, a fan, a valve and a pipeline; the fan outlet is connected to the pretreatment equipment inlet through a pipeline, the pretreatment equipment outlet is connected to the collector air inlet through a pipeline, and each inlet and outlet of the collector are connected to the corresponding valves through pipelines.

[0013] The pretreatment equipment is used to remove dust and moisture from the air to prevent dust or excessive moisture in the air from entering the collector and affecting the adsorption effect. Generally, a filter and a dehumidifier are used.

[0014] The third aspect of the present invention provides a method for direct air capture of carbon dioxide, comprising the following contents: (1) Open the air inlet and air outlet valves, close the carbon dioxide outlet valve, and start the fan; adjust the temperature of the electric heater to the adsorption temperature T1, so that the electric heating element is heated and maintained at the adsorption temperature; after the air flows through the pretreatment equipment under the action of the fan to remove the dust and excess moisture contained in it, it enters the cylinder from the air inlet of the collector and flows along the channel formed by the inner wall of the cylinder and the electric heating element and between the electric heating elements; the carbon dioxide in the air flows through the electric heating element and is adsorbed by the solid adsorbent on the surface, and the carbon dioxide-depleted air flows out from the air outlet and is discharged into the atmosphere. This process is the adsorption process, which needs to last for a certain period of time to allow the adsorbent to reach adsorption saturation; (2) After the solid adsorbent is saturated with adsorption, turn off the fan, open the air outlet valve, and close the air inlet valve and the carbon dioxide outlet valve; adjust the temperature of the electric heater to the preheating temperature T2, so that the electric heating element heats up and maintains the preheating temperature for 5 to 10 minutes. The volume of the air in the channel and the pores of the adsorbent expands as the temperature rises, and part of the air is discharged from the air outlet; then adjust the valve stem action so that the valve stem is lifted from the bottom of the collector to the top, and the air in the channel is completely discharged from the air outlet under the push of the valve plate. The above process is the purge process, which discharges the air in the channel and most of the air in the adsorbent air to prepare for the desorption of carbon dioxide; (3) Open the carbon dioxide outlet valve, close the air inlet valve and the air outlet valve. As the valve plate moves up, a certain negative pressure is generated in the cylinder. Adjust the temperature of the electric heater to the desorption temperature T3, so that the electric heating element continues to heat up and maintain the desorption temperature for a certain period of time. Under the simultaneous action of high temperature and negative pressure, the carbon dioxide adsorbed by the solid adsorbent is gradually desorbed. As the amount of carbon dioxide desorbed increases, the pressure in the cylinder gradually rises. When the pressure no longer changes, adjust the valve stem again to make the valve stem drop from the top of the collector to the bottom. The carbon dioxide in the channel is completely discharged from the carbon dioxide outlet under the push of the valve plate. This process is the desorption process. (4) Close the CO2 outlet valve, open the air inlet valve and the air outlet valve, stop the electric heater from heating, and start the fan; after the air flows through the pretreatment equipment under the action of the fan to remove the dust and excess moisture contained in it, it enters the cylinder from the air inlet of the collector and continues to flow forward along the channel formed by the inner wall of the cylinder and the electric heating element, so that the electric heating element and the solid adsorbent are cooled to the adsorption temperature T1; (5) Repeat steps (1) to (4) to realize the adsorption-purge-desorption-cooling cycle process of direct air capture of carbon dioxide.

[0015] Furthermore, the adsorption temperature T1, preheating temperature T2, desorption temperature T3, adsorption time and desorption time are determined according to the type of solid adsorbent, wherein the adsorption time includes the total time of heating to the adsorption temperature and maintaining the adsorption temperature, and the desorption time includes the total time of heating to the desorption temperature and maintaining the desorption temperature.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The electric heating plate in the collector acts as a partition to separate the internal space of the cylinder, so that the air flows along a longer one-way channel from the air inlet to the air outlet in the limited space of the cylinder, which increases the contact time and contact area between the air and the adsorbent and improves the adsorption efficiency.

[0017] 2. The adsorbent is evenly coated on the outer surface of the electric heating plate, so that the adsorbent at each position is heated at the same time and evenly heated, thereby improving the desorption efficiency of carbon dioxide.

[0018] 3. The driving force of the valve plate is used to discharge the residual air in the cylinder before the desorption step, and the carbon dioxide remaining in the cylinder after desorption is discharged, and the obtained carbon dioxide has high purity; it can not only save the vacuum pump required for traditional vacuum desorption, but also avoid the subsequent separation problems caused by water vapor purge desorption.

[0019] 4. The electric heater adopts a detachable flange connection, which is convenient for replacing the electric heating element and the adsorbent. The device has a simple structure, small footprint, and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the carbon dioxide direct air capture device of the present invention.

[0021] Figure 2 It is a schematic diagram of an arrangement of electric heating elements in the collector of the present invention.

[0022] Figure 3 It is a schematic diagram of another arrangement of the electric heating elements in the collector of the present invention.

[0023] Figure 4 The present invention is a schematic diagram of a capture device of a carbon dioxide direct air capture device.

[0024] Among them, 1 is a cylinder, 2 is an electric heating element, 3 is a solid adsorbent, 4 is a flange, 5 is an electric heater, 6 is a control box, 7 is a carbon dioxide outlet pipe, 8 is an air inlet pipe, 9 is a valve plate, 10 is a valve stem, 11 is an inner insulation layer, 12 is a side wall, 13 is a top plate, 14 is an air outlet pipe, and 15 is a valve stem drive member; I—air to be adsorbed, II—air after adsorption and capture, III—captured carbon dioxide; 101—fan, 102—pretreatment equipment, 103—collector, 104—air inlet valve, 105—air outlet valve, 106—carbon dioxide outlet valve. DETAILED DESCRIPTION

[0025] The present invention will be further described below by way of specific examples, but is not limited to the following examples. Example 1

[0026] Combination Figure 1 and Figure 2 , a carbon dioxide direct air collector of the present invention is as follows: A carbon dioxide direct air collector comprises a cylinder 1, an electric heater 5, a valve plate 9 and a valve stem 10; a top plate 13 is provided on the top of the cylinder 1, and a valve stem hole is opened on the top plate 13 for the valve stem 10 to move up and down; an air outlet pipe 14 is provided on the upper part of the cylinder 1, a carbon dioxide outlet pipe 7 is provided on the lower part of the cylinder 1, and an air inlet pipe 8 is provided on the side wall 12 of the cylinder 1; the bottom of the cylinder 1 is connected to the electric heater 5 through a flange 4; the side wall 12 of the cylinder, the top plate 13 and the flange 4 are all provided with a 35mm thick ceramic fiber inner insulation layer 11; the electric heating element 2 is arranged inside the cylinder 1 in parallel with the central axis of the cylinder 1; the bottom end of the electric heating element 2 is connected to the top of the electric heater 5, and the top end is connected to the inner insulation layer 11 of the top plate 13; the front and rear surfaces of the electric heating element 2 are evenly coated with a solid amine adsorbent 3 with a thickness of about 500μm by an adhesive, and the outer surface after coating should be flat and sufficiently smooth; In the collector of the present invention, the electric heater 5 is a detachable structure, and the temperature of the electric heating element 2 can be adjusted through the control box; the electric heating element 2 is a large piece of integral ceramic electric heating plate, and serves as a partition plate to separate the internal space of the cylinder 1, so that the air flows along a unidirectional and relatively long integral channel from the air inlet 8 to the air outlet 14 in the limited space of the cylinder 1; the electric heating element 2 is arranged in a spiral-like manner that rotates along a certain shape with the central axis of the cylinder 1 as the center and gradually moves away from the center, and its rotating shape is circular, and the formed unidirectional channel is spiral; the gas in the cylinder 1 moves along the integral channel formed by the electric heating element 2, and the width of the integral channel perpendicular to the flow direction is 50 mm; In the trap of the present invention, the valve plate 9 is connected to the valve stem 10, the valve plate 9 covers the cross section of the entire channel (wherein the cross section does not include the wall thickness of the channel formed by the electric heating element 2), and the number of the valve stem 10 is one; the valve stem 10 is arranged parallel to the central axis of the cylinder 1, and the valve stem 10 drives the valve plate 9 to move up and down along the inner wall of the channel under the action of the hydraulic drive 15; the thickness of the valve plate 9 is 10 mm, and the diameter of the valve stem 10 is 50 mm; all edges of the valve plate 9 are evenly coated with a layer of carbon fiber sealing material; In the collector of the present invention, the cylinder 1 is a circular cylinder with a diameter of 1000 mm and a height of 1500 mm, and the thickness of the top plate 13 and the side wall 12 thereof is 10 mm; the outer periphery of the cylinder top plate 13 is sealed and welded to the upper edge of the cylinder side wall 12, and a flange 4 is provided at the lower end of the cylinder 1, and the flange 4 is sealed and welded to the cylinder side wall 12; In the collector of the present invention, the air inlet pipe 8, the air outlet pipe 14 and the carbon dioxide outlet pipe 7 are all provided with corresponding valves and pipelines, and the valves are all switch valves; the cylinder 1 and its flange 4, the valve stem 10 and the valve plate 9 are made of stainless steel.

[0027] Recombination Figure 4 , a carbon dioxide direct air capture method of the present invention is as follows: (1) Open the air inlet valve 104 and the air outlet valve 105, close the carbon dioxide outlet valve 106, and start the fan 101; adjust the temperature of the electric heater 5 to the adsorption temperature of 25°C, and after the adsorption treated air I flows through the pretreatment equipment 102 under the action of the fan 101 to remove the dust and excess moisture contained therein, it enters the interior of the cylinder 1 from the air inlet valve 104 of the collector 103, and flows along the channel surrounded by the inner wall of the cylinder 1 and the electric heating element 2, and the electric heating element 2; the carbon dioxide in the air is adsorbed by the solid amine adsorbent 3 on the surface when flowing through the electric heating element 2, and the air II after adsorption and capture flows out from the air outlet 14 to the atmosphere, and the adsorption time is 60 minutes; (2) After the solid adsorbent is saturated with adsorption, the fan 101 is turned off, the air outlet valve 105 is opened, and the air inlet valve 104 and the carbon dioxide outlet valve 106 are closed; the temperature of the electric heater 5 is adjusted to the preheating temperature of 60°C and the preheating temperature is maintained for 10 minutes. The volume of the air in the channel and the pores of the adsorbent expands as the temperature rises, and part of the air is discharged from the air outlet; then the valve stem 10 is adjusted to move so that the valve stem 10 is lifted from the bottom of the collector 103 to the top, and the air in the channel is completely discharged from the air outlet 14 under the push of the valve plate 9. The above process is a purge process, which discharges the air in the channel and most of the air in the adsorbent air to prepare for the desorption of carbon dioxide; (3) Open the carbon dioxide outlet valve 106, close the air inlet valve 104 and the air outlet valve 105. As the valve plate 9 moves upward, a certain negative pressure is generated in the cylinder 1. Adjust the temperature of the electric heater 5 to the desorption temperature of 120°C. Under the simultaneous action of high temperature and negative pressure, the carbon dioxide adsorbed by the solid amine adsorbent 3 is gradually desorbed. As the amount of carbon dioxide desorbed increases, the pressure in the cylinder 1 gradually rises. When the pressure no longer changes, adjust the valve stem 10 again to make the valve stem 10 drop from the top of the collector 103 to the bottom. The captured carbon dioxide III is completely discharged from the carbon dioxide outlet 7 under the push of the valve plate 9. This process is the desorption process, and the desorption time is 35 minutes. (4) Close the carbon dioxide outlet valve 106, open the air inlet valve 104 and the air outlet valve 105, stop the electric heater 5 from heating, and start the fan 101; after the air flows through the pretreatment equipment 102 under the action of the fan 101 to remove the dust and excess moisture contained therein, it enters the cylinder 1 from the air inlet valve 104 of the collector 103, and continues to flow forward along the channel surrounded by the inner wall of the cylinder 1 and the electric heating element 2, so that the electric heating element 2 and the solid amine adsorbent 3 are cooled to the adsorption temperature of 25°C, and the cooling time is 15 minutes; (5) Repeat steps (1) to (4) to realize the adsorption-purge-desorption-cooling cycle process of direct air capture of carbon dioxide.

[0028] The adsorption-purge-desorption-cooling cycle of direct air capture of carbon dioxide is realized according to the above method, and the purity of the obtained carbon dioxide is 90%. Example 2

[0029] Combination Figure 1 and Figure 3 , a carbon dioxide direct air collector of the present invention is as follows: A carbon dioxide direct air collector comprises a cylinder 1, an electric heater 5, a valve plate 9 and a valve stem 10; a top plate 13 is provided on the top of the cylinder 1, and two valve stem holes are opened on the top plate 13 for the valve stem 10 to move up and down; an air outlet pipe 14 is provided on the upper part of the cylinder 1, a carbon dioxide outlet pipe 7 is provided on the lower part of the cylinder 1, and an air inlet pipe 8 is provided on the side wall 12 of the cylinder 1; the bottom of the cylinder 1 is connected to the electric heater 5 through a flange 4; the cylinder side wall 12, the top plate 13 and the flange 4 are all provided with a 50mm thick ceramic fiber inner insulation layer 11; the electric heating element 2 is arranged inside the cylinder 1 in parallel with the central axis of the cylinder 1; the bottom end of the electric heating element 2 is connected to the top of the electric heater 5, and the top end is connected to the inner insulation layer 11 of the top plate 13; the front and rear surfaces of the electric heating element 2 are evenly coated with a MOFs adsorbent 3 with a thickness of about 200μm by an adhesive, and the outer surface after coating should be flat and sufficiently smooth; In the collector of the present invention, the electric heater 5 is a detachable structure, and the temperature of the electric heating element 2 can be adjusted through the control box; the electric heating element 2 is a plurality of ceramic electric heating plates, and serves as a partition plate to separate the internal space of the cylinder 1, so that the air flows along a unidirectional and relatively long overall channel from the air inlet 8 to the air outlet 14 in the limited space of the cylinder 1; one end of the electric heating element 2 is fixedly connected to the two corresponding inner walls of the cylinder 1 in front and behind in sequence, and the other end is sequentially connected to the inner wall of the cylinder 1 opposite to the connection end to maintain a 50mm length gap, and the formed unidirectional channel is in a zigzag shape, and the gas in the cylinder 1 moves along the channel formed by the electric heating element 2, and the width of the overall channel perpendicular to the flow direction is 50mm; In the trap of the present invention, the valve plate 9 is connected to the valve stem 10, the valve plate 9 covers the cross section of the entire channel (wherein the cross section does not include the wall thickness of the channel formed by the electric heating element 2), and the number of valve stems 10 is 2; the valve stem 10 is arranged parallel to the central axis of the cylinder 1, and the valve stem 10 drives the valve plate 9 to move up and down along the inner wall of the channel under the action of the hydraulic drive 15; the thickness of the valve plate 9 is 10 mm, and the diameter of the valve stem 10 is 50 mm; all edges of the valve plate 9 are evenly coated with a layer of carbon fiber sealing material; In the collector of the present invention, the cylinder 1 is a rectangular cylinder with a length, a width and a height of 1300 mm, 1300 mm and 1500 mm respectively, and the thickness of the top plate 13 and the side wall 12 is 16 mm; the outer periphery of the cylinder top plate 13 is sealed and welded to the upper edge of the cylinder side wall 12, and a flange 4 is provided at the lower end of the cylinder, and the flange 4 is sealed and welded to the cylinder side wall 12; the cylinder side wall 12 and the top plate 13 are provided with a plurality of reinforcing ribs; In the collector of the present invention, the air inlet pipe 8, the air outlet pipe 14 and the carbon dioxide outlet pipe 7 are all provided with corresponding valves and pipelines, and the valves are all switch valves; the cylinder 1 and its flange 4, the valve stem 10 and the valve plate 9 are made of stainless steel.

[0030] Recombination Figure 4 , a carbon dioxide direct air capture method of the present invention is as follows: (1) Open the air inlet valve 104 and the air outlet valve 105, close the carbon dioxide outlet valve 106, and start the fan 101; adjust the temperature of the electric heater 5 to the adsorption temperature of 30°C, and after the adsorbed air I flows through the pretreatment equipment 102 under the action of the fan 101 to remove the dust and excess moisture contained therein, it enters the interior of the cylinder 1 from the air inlet valve 104 of the collector 103, and flows along the channel surrounded by the inner wall of the cylinder 1 and the electric heating element 2, and the electric heating element 2; the carbon dioxide in the air is adsorbed by the MOFs adsorbent 3 on the surface when flowing through the electric heating element 2, and the air II after adsorption and capture flows out from the air outlet 14 to the atmosphere, and the adsorption time is 60 minutes; (2) After the solid adsorbent is saturated with adsorption, the fan 101 is turned off, the air outlet valve 105 is opened, and the air inlet valve 104 and the carbon dioxide outlet valve 106 are closed; the temperature of the electric heater 5 is adjusted to the preheating temperature of 45°C and maintained for 5 minutes. The volume of the air in the channel and the pores of the adsorbent expands as the temperature rises, and part of the air is discharged from the air outlet; then the valve stem 10 is adjusted to move so that the valve stem 10 is lifted from the bottom of the collector 103 to the top, and the air in the channel is completely discharged from the air outlet 14 under the push of the valve plate 9. The above process is a purge process, which discharges the air in the channel and most of the air in the adsorbent air to prepare for the desorption of carbon dioxide; (3) Open the carbon dioxide outlet valve 106, close the air inlet valve 104 and the air outlet valve 105. As the valve plate 9 moves upward, a certain negative pressure is generated in the cylinder 1. The temperature of the electric heater 5 is adjusted to the desorption temperature of 90°C. Under the simultaneous action of high temperature and negative pressure, the carbon dioxide adsorbed by the MOFs adsorbent 3 is gradually desorbed. As the amount of carbon dioxide desorbed increases, the pressure in the cylinder 1 gradually rises. When the pressure no longer changes, adjust the valve stem 10 again to make the valve stem 10 drop from the top of the collector 103 to the bottom. The captured carbon dioxide III is completely discharged from the carbon dioxide outlet 7 under the push of the valve plate 9. This process is the desorption process, and the desorption time is 45 minutes. (4) Close the carbon dioxide outlet valve 106, open the air inlet valve 104 and the air outlet valve 105, stop the electric heater 5 from heating, and start the fan 101; after the air flows through the pretreatment equipment 102 under the action of the fan 101 to remove the dust and excess moisture contained therein, it enters the interior of the cylinder 1 from the air inlet valve 104 of the collector 103, and continues to flow forward along the channel surrounded by the inner wall of the cylinder 1 and the electric heating element 2, so that the electric heating element 2 and the MOFs adsorbent 3 are cooled to the adsorption temperature of 30°C, and the cooling time is 10 minutes; (5) Repeat steps (1) to (4) to realize the adsorption-purge-desorption-cooling cycle process of direct air capture of carbon dioxide.

[0031] The adsorption-purge-desorption-cooling cycle of direct air capture of carbon dioxide is realized according to the above method, and the purity of the obtained carbon dioxide is 92%.

Claims

1. A carbon dioxide direct air collector, characterized in that include: Cylinder, electric heater, electric heating element, valve plate, valve stem; The top of the cylinder is provided with a top plate, which is provided with one or more valve stem holes for the valve stem to move up and down; the upper part of the cylinder is provided with an air outlet, the lower part of the cylinder is provided with a carbon dioxide outlet, and the side wall of the cylinder is provided with an air inlet; the bottom of the cylinder is connected to the electric heater through a flange; the side wall, top plate and flange of the cylinder are all provided with an inner insulation layer of a certain thickness; The electric heating element is arranged inside the cylinder parallel to the central axis of the cylinder, and is arranged to form a one-way channel from the air inlet end to the air outlet end, and the channel length is greater than the longest distance between two points on the cross section of the cylinder; the bottom end of the electric heating element is connected to the top of the electric heater, and the top end is connected to the inner insulation layer of the top plate; the surface of the electric heating element is coated with a solid adsorbent of a certain thickness; The valve plate is connected to the valve stem, the valve plate covers the entire cross-section of the channel, the valve stem is arranged parallel to the central axis of the cylinder, and the valve stem drives the valve plate to move up and down along the inner wall of the channel.

2. The collector according to claim 1, characterized in that: The cross section of the cylinder is circular or polygonal; a flange is arranged at the lower end of the cylinder, and the flange is sealed and welded to the side wall of the cylinder; the thickness of the inner insulation layer is 20-100 mm.

3. The collector according to claim 1, characterized in that: The electric heater is a detachable structure, and the temperature of the electric heating element is adjusted by a control box; the electric heating element is a large piece or several small pieces, which are determined according to the arrangement method.

4. The collector according to claim 1, characterized in that: The gas in the cylinder moves along the one-way channel formed by the electric heating element; the width of the one-way channel perpendicular to the gas flow direction is 20-500 mm, preferably 50-300 mm.

5. The collector according to claim 1, characterized in that: The one-way channel is a quasi-spiral one-way channel or a zigzag one-way channel.

6. The trap according to claim 1, characterized in that: The electric heating elements are arranged in a spiral manner, rotating along a certain shape with the central axis of the cylinder as the center and gradually moving away from the center. The rotating shape is circular or polygonal, preferably circular and rectangular, and the one-way channel formed is spiral-like; or the electric heating elements are arranged in a parallel and staggered manner to form a zigzag one-way channel, one end of which is fixedly connected to the corresponding inner wall of the cylinder along the length direction of the electric heating elements, and the other end maintains a certain gap with the opposite inner wall of the cylinder, and the length of the gap is 20~500mm, preferably 50~300mm.

7. The collector according to claim 1, characterized in that: All edges of the valve plate are evenly coated with a layer of sealing material, and the sealing material is preferably graphite, tetrafluoroethylene or carbon fiber material; the thickness of the valve plate is not less than 10mm, and the diameter of the valve stem is not less than 50mm.

8. The trap according to claim 1, characterized in that: There are one or more valve stems; the valve stem moves up and down along the central axis of the cylinder under the action of air pressure or hydraulic drive.

9. The trap according to claim 1, characterized in that: The number of the top plate valve stem holes is the same as the number of the valve stems, and packing is used to seal between the valve stem holes and the valve stems.

10. The collector according to claim 1, characterized in that: The air inlet, air outlet and carbon dioxide outlet are all provided with corresponding valves and pipelines, and the valves are all switch valves; the material of the cylinder and its flange, valve stem and valve plate is stainless steel; the material of the inner insulation layer is industrial general insulation cotton.

11. The collector according to claim 1, characterized in that: The solid adsorbent is a solid amine adsorbent or a MOFs adsorbent. The solid adsorbent is evenly coated on the outer surface of the electric heating element through an adhesive. The outer surface after coating should be flat and smooth enough.

12. Use of the carbon dioxide direct air capture device according to any one of claims 1 to 11 in carbon dioxide direct air capture.

13. A carbon dioxide direct air capture system, the system comprising the carbon dioxide direct air capture device as described in any one of claims 1 to 11, a pretreatment device, a fan, a valve and a pipeline; the fan outlet is connected to the pretreatment device inlet through a pipeline, the pretreatment device outlet is connected to the collector air inlet through a pipeline, and each inlet and outlet of the collector are connected to the corresponding valves through pipelines.

14. The capture system according to claim 13, characterized in that: The pretreatment equipment is used to remove dust and moisture from the air, so as to prevent dust or excessive moisture in the air from entering the collector and affecting the adsorption effect.

15. A method for direct air capture of carbon dioxide using the capture system of claim 13, characterized in that It includes the following: (1) Open the air inlet and air outlet valves, close the carbon dioxide outlet valve, and start the fan; adjust the temperature of the electric heater to the adsorption temperature T1, so that the electric heating element is heated and the adsorption temperature is maintained; after the air flows through the pretreatment equipment under the action of the fan to remove the dust and excess moisture contained in it, it enters the cylinder from the air inlet of the collector and flows along the one-way channel formed by the inner wall of the cylinder and the electric heating element and between the electric heating elements; When the carbon dioxide in the air flows through the electric heating element, it is adsorbed by the solid adsorbent on the surface, and the carbon dioxide-depleted air flows out from the air outlet and is discharged into the atmosphere. This process is the adsorption process, which needs to last for a certain period of time to allow the adsorbent to reach adsorption saturation. (2) After the solid adsorbent is saturated with adsorption, turn off the fan, open the air outlet valve, and close the air inlet valve and the carbon dioxide outlet valve. Adjust the temperature of the electric heater to the preheating temperature T2, so that the electric heating element heats up and maintains the preheating temperature for 5 to 10 minutes. The volume of the air in the channel and the adsorbent pores expands as the temperature rises, and part of the air is discharged from the air outlet. Then adjust the valve stem action so that the valve stem is lifted from the bottom of the collector to the top, and the air in the channel is completely discharged from the air outlet under the push of the valve plate. The above process is the purge process, which discharges the air in the channel and most of the air in the adsorbent air to prepare for the desorption of carbon dioxide. (3) Open the carbon dioxide outlet valve, close the air inlet valve and the air outlet valve. As the valve plate moves up, a certain negative pressure is generated in the cylinder. Adjust the electric heating element to The temperature of the heater is the desorption temperature T3, so that the electric heating element continues to heat up and maintain the desorption temperature for a certain period of time. Under the simultaneous action of high temperature and negative pressure, the carbon dioxide adsorbed by the solid adsorbent is gradually desorbed. As the amount of carbon dioxide desorbed increases, the pressure in the cylinder gradually rises. When the pressure no longer changes, the valve stem is adjusted again to make the valve stem drop from the top of the collector to the bottom. The carbon dioxide in the channel is completely discharged from the carbon dioxide outlet under the push of the valve plate. This process is the desorption process; (4) Close the carbon dioxide outlet valve, open the air inlet valve and the air outlet valve, stop heating the electric heater, and start the fan; after the air flows through the pretreatment equipment under the action of the fan to remove the dust and excess moisture contained in it, it enters the cylinder from the air inlet of the collector and continues to flow forward along the channel surrounded by the inner wall of the cylinder and the electric heating element, so that the electric heating element and the solid adsorbent are cooled to the adsorption temperature T1; (5) Repeat steps (1) to (4) to realize the adsorption-purge-desorption-cooling cycle of direct air capture of carbon dioxide.

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