A direct air carbon capture system and method

Abstract

The application discloses a direct air carbon capture system and method, and relates to the technical field of carbon capture, and in particular to a direct air carbon capture system and method. The system comprises a lye absorption and regeneration integrated device, a heat pump system, a ripener, a calcining furnace, a condenser separator and a compressor. The lye absorption and regeneration integrated device is composed of a shell, an arched biomass carbon material gas absorption plate, a lean liquid tank, a particle reaction tank, a filter and a solution pump. CO2 absorption occurs on the surface of the biomass carbon material gas absorption plate, and due to capillary action, siphon phenomenon caused by the height difference between the lean liquid tank and the particle reaction tank and ion concentration difference, directional transfer of lean liquid and rich liquid is realized. The heat pump system is used for recovering water vapor in decarburized air and CaCO2 primary preheating. CaO ripening reaction heat is used for CaCO3 secondary preheating. The application utilizes the pore structure of the biomass carbon material gas absorption plate, capillary phenomenon and siphon effect to improve CO2 absorption rate and save pump power. The application utilizes the heat pump system to save water resources. The application utilizes system waste heat to reduce system energy consumption.

Description

Technical Field

[0001] This invention relates to the field of air carbon capture, and more particularly to a direct air carbon capture system and method. Background Technology

[0002] Direct CO2 capture in the air (DAC) differs from traditional carbon capture, utilization and storage (CCUS). It can flexibly address CO2 emissions from tens of thousands of fossil fuel installations of varying sizes and mobile sources such as various vehicles. Furthermore, the installation of carbon capture devices is not limited by time, space or geographical location, making it a very commercially promising CO2 emission reduction technology.

[0003] Currently, apart from a small amount of biomass that is effectively utilized, most biomass is landfilled or incinerated, which is very environmentally unfriendly. Biomass carbon materials, formed by simple carbonization of biomass raw materials, have a unique micro-nano porous structure and excellent material properties, and have application potential in hot fields such as energy storage, environmental protection, and interfacial photothermal evaporation.

[0004] Common gas absorption towers include bubble column towers and spray column towers. In bubble column towers, the enrichment effect of gas in the liquid phase is affected by factors such as liquid properties and bubble diameter. In spray column towers, liquid droplets cannot fully contact the gas, and the spraying of droplets and gas flow generate noise and vibration. Enhancing the gas-liquid contact effect is key to developing new types of gas absorption towers. Summary of the Invention

[0005] In view of the above, the present invention provides a direct air carbon capture system and method. The present invention adopts the following technical solution:

[0006] A direct air carbon capture system includes an integrated alkaline absorption and regeneration device, a heat pump system, a curing unit, a calcining furnace, a condenser separator, and a compressor;

[0007] The integrated alkaline solution absorption and regeneration unit is connected to the heat pump system and the ripening device piping, respectively.

[0008] The heat pump system is connected to the integrated alkali absorption and regeneration unit and the ripening unit via pipelines.

[0009] The curing unit is connected to the integrated alkaline solution absorption and regeneration device, the heat pump system, and the calcining furnace pipeline.

[0010] The calcining furnace is connected to the curing unit and the condenser via pipelines; the condenser is connected to the compressor via pipelines.

[0011] As a further preferred embodiment, the integrated alkaline solution absorption and regeneration device has a tower structure, including a lean solution tank, a shell, a biomass carbon material gas absorption plate, a particle reaction tank, a filter, and a solution pump. The shell is equipped with an air inlet pipe and a gas outlet pipe. The biomass carbon material absorption plate has an arched structure, with one end immersed in the lean solution tank and the other end immersed in the particle reaction tank. The lean solution tank is positioned higher than the particle reaction tank.

[0012] The particle reaction tank is connected to the filter pipeline, and the filter is connected to the lean solution tank pipeline via a solution pump.

[0013] The granulation reactor is connected to the ripening unit via piping.

[0014] The filter is connected to the heat pump system piping.

[0015] As a further preferred embodiment, the heat pump system includes an evaporator, a compressor, a condenser, and an expansion valve. The evaporator is connected to the casing via a gas outlet pipe and has two outlets: one for decarbonized air and one for condensate. The condenser is connected to both a filter and a condenser pipe.

[0016] As a further preferred option, biomass carbon material absorber plates are prepared from biomass raw materials with natural porous structures through processes such as freezing, carbonization, and molding. The biomass raw materials used include, but are not limited to, plant trunks, roots, leaves, and fruits. In addition to being made into plates, the original shape of the biomass carbon material can also be made into tubes, which are then processed into arches.

[0017] A method for capturing carbon in a direct air capture system includes the following steps:

[0018] Step 1: The lean liquid is drawn from the lean liquid tank into the biomass carbon material gas absorption plate through capillary action and siphon effect, and is uniformly adsorbed in the pore structure of the biomass carbon material gas absorption plate, where it reacts with CO2 in the air introduced from the gas inlet of the shell to generate rich liquid.

[0019] Step 2: The rich solution is transferred to the particle reaction tank under the siphon effect and the ion concentration difference. In the particle reaction tank, it reacts with Ca(OH)2 to form a precipitate. The precipitate enters the filter, and the filtered liquid phase is the regenerated lean solution. The lean solution is returned to the lean solution tank through the solution pump.

[0020] Step 3: The solids produced by the filter are preheated in the heat pump system condenser, then preheated in the curing unit, and finally enter the calcining furnace. Calcination in the calcining furnace desorbs CO2. The CO2 released during calcination is condensed in the condenser separator and then compressed by the compressor to obtain high-concentration CO2. High-concentration CO2 can be utilized physically, chemically, biologically, geologically, or geologically stored.

[0021] Step 4: The CaO generated from calcining CaCO3 in the calcining furnace enters the ripening tank and reacts with water to generate Ca(OH)2 slurry. This slurry enters the particle reaction tank and reacts with the rich liquor to achieve lean liquor regeneration.

[0022] Step 5: The decarbonized air is discharged from the gas outlet pipe of the shell into the evaporator of the heat pump system, where it is cooled, achieving gas-water separation. The gas is then discharged. The water can be returned to the lean liquid tank as makeup liquid.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. This invention integrates an alkaline solution absorption and regeneration device, which utilizes the porous structure of biomass carbon materials to increase the gas-liquid contact area and extend the gas-liquid contact time, thereby improving the gas absorption rate.

[0025] 2. This invention utilizes the capillary action of biomass carbon materials, the siphon effect generated by the height difference between the lean solution tank and the particle reaction tank, and the ion concentration difference to achieve directional transfer of lean and rich solutions, saving the power consumption of the liquid pump.

[0026] 3. This invention adds a heat pump system to recover moisture from the decarbonized gas and preheat the CaCO3 particles in the first stage, thereby reducing water consumption and lowering system energy consumption.

[0027] 4. This invention utilizes the heat released by the CaO ripening reaction to perform secondary preheating of CaCO3 particles, further reducing system energy consumption. Attached Figure Description

[0028] Figure 1 This is a structural diagram of the integrated alkali absorption and regeneration device of the present invention;

[0029] Figure 2 Schematic diagram of an integrated alkaline solution absorption and regeneration device;

[0030] Figure 3 Flowchart of a direct air carbon capture system;

[0031] In the diagram, 101 is the lean solution tank; 102 is the shell; 103 is the biomass carbon material gas absorption plate; 104 is the particle reaction tank; 105 is the filter; 106 is the solution pump; 201 is the integrated alkaline solution absorption and regeneration device; 202 is the heat pump system; 203 is the curing device; 204 is the calcining furnace; 205 is the condenser separator; 206 is the CO2 compressor; 301 is the heat pump system evaporator; 302 is the refrigerant compressor; 303 is the heat pump system condenser; and 304 is the refrigerant expansion valve. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Example 1

[0034] like Figure 1 As shown, Example 1 of the present invention provides an integrated alkaline absorption and regeneration device for a direct air carbon capture system, including a lean solution tank 101, a shell 102, an arched biomass carbon material gas absorption plate 103, a particle reaction tank 104, a filter 105, and a solution pump 106.

[0035] The shape and arrangement of biomass carbon material gas absorption plates are as follows: Figure 1 , Figure 2 As shown, one end of the biomass carbon material gas absorber plate is immersed in the lean liquor tank, and the other end is immersed in the particle reaction tank, with the lean liquor tank positioned higher than the particle reaction tank. Those skilled in the art can select the number and arrangement of the carbon material interface absorber plates according to specific circumstances; details will not be elaborated here.

[0036] In this example, preferably, the lean liquid is transferred from the lean liquid tank 101 to the biomass carbon material gas absorption plate 103 through capillary action and siphon effect. The lean liquid is uniformly adsorbed in the pore structure of the biomass carbon material gas absorption plate 103 and reacts with the air introduced from the gas inlet of the shell 102 to generate a rich liquid.

[0037] CO2 + 2NaOH → Na2CO3 + H2O (Equation 1)

[0038] The rich solution is transferred to the particle reaction tank 104 driven by the ion concentration gradient, where a precipitate is formed.

[0039] Na2CO3+Ca(OH)2→2NaOH+CaCO3 Formula (2)

[0040] The precipitate enters the filter 105 for filtration. The liquid phase after precipitate filtration is the regenerated lean solution. The lean solution flows into the lean solution tank 101 through the solution pump 106 for re-reaction.

[0041] In this example, preferably, the biomass carbon material absorption plate 103 is prepared from biomass raw materials with natural porous structures through processes such as freezing, carbonization, and molding. The biomass raw materials used include, but are not limited to, plant trunks, roots, leaves, and fruits. Besides being made into plates, the original shape of the biomass carbon material can also be made into tubes, which are then processed into arches. Those skilled in the art can select the biomass and processing methods according to specific circumstances, which will not be elaborated upon here.

[0042] The alkaline absorption and regeneration integrated device for direct air carbon capture described in this invention can also be connected and integrated with CO2 desorption equipment to form a complete direct air carbon capture system.

[0043] Example 2:

[0044] The present invention provides a direct air carbon capture system, including the integrated alkaline absorption and regeneration device described in Embodiment 1 of the present invention.

[0045] like Figure 3 As shown, the present invention also provides a direct air carbon capture system, comprising: an integrated alkaline absorption and regeneration device 201, a heat pump system 202, a curing device 203, a calcining furnace 204, a condenser separator 205, and a CO2 compressor 206.

[0046] In this example, the NaOH solution in the lean solution tank 101 flows through the porous structure of the biomass carbon material gas absorption plate 103, reacting with CO2 in the air to generate Na2CO3 solution:

[0047] CO2 + 2NaOH → Na2CO3 + H2O (Equation 1)

[0048] The generated Na2CO3 solution undergoes a causticizing reaction with Ca(OH)2 solution in particle reaction tank 104 to generate NaOH solution and CaCO3 precipitate, as shown in formula (2), thereby achieving NaOH regeneration:

[0049] Na2CO3+Ca(OH)2→2NaOH+CaCO3 Formula (2)

[0050] The sediment from the outlet of the particle reaction tank 104 enters the filter 105. The filtered solution is then pressurized by the solution pump 106 and fed into the lean solution tank 101 for circulation.

[0051] The solids produced by the filter 105 are preheated in the heat pump system condenser 303 (first stage), then preheated in the curing tank 203 (second stage), and finally calcined in the calcining furnace 204, as shown in equation (3), to achieve CO2 desorption.

[0052] CaCO3→CaO+CO2 Equation (3)

[0053] The generated high-temperature CO2 is condensed and separated into low-temperature dried CO2 by condenser 205, and then compressed by CO2 compressor 206 to obtain high-concentration CO2. High-concentration CO2 can be used for physical, chemical, biological, geological, or geological sequestration.

[0054] The CaO generated by calcination undergoes a hydration reaction with water in the curing tank 203 to generate Ca(OH)2, thus regenerating Ca(OH)2. See equation (4):

[0055] CaO + H₂O → Ca(OH)₂ (Equation 4)

[0056] The decarbonized air is discharged from the gas outlet pipe of the casing 102 into the heat pump system evaporator 301, where it is cooled, achieving gas-water separation. The gas is then discharged. The water can be returned to the lean liquid tank 101 as makeup liquid.

[0057] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A direct air carbon capture system, characterized in that: It includes an integrated alkaline absorption and regeneration device (201), a heat pump system (202), a curing device (203), a calcining furnace (204), a condenser (205), and a CO2 compressor (206). The integrated alkaline absorption and regeneration device (201) is connected to the heat pump system (202) and the ripening device (203) via pipelines respectively; The heat pump system (202) is connected to the integrated alkaline absorption and regeneration device (201) and the ripening device (203) via pipelines respectively; The ripening device (203) is connected to the integrated alkaline absorption and regeneration device (201), the heat pump system (202), and the calcining furnace (204) via pipelines. The calcining furnace (204) is connected to the curing unit (203) and the condenser (205) via pipelines; the condenser (205) is connected to the CO2 compressor (206) via pipelines. The integrated alkaline absorption and regeneration device (201) has a tower structure, including a lean solution tank (101), a shell (102), a biomass carbon material gas absorption plate (103), a particle reaction tank (104), a filter (105), and a solution pump (106). The shell (102) is provided with an air inlet pipe and a gas outlet pipe. The biomass carbon material gas absorption plate (103) has an arched structure, with one end immersed in the lean solution tank (101) and the other end immersed in the particle reaction tank (104). The lean solution tank (101) is positioned higher than the particle reaction tank (104). The particle reaction tank (104) is connected to the filter (105) by a pipeline, and the filter (105) is connected to the lean liquid tank (101) by a solution pump (106); The particle reaction tank (104) is connected to the ripening device (203) by a pipe; The filter (105) is connected to the heat pump system (202) via piping.

2. The direct air carbon capture system according to claim 1, characterized in that: The heat pump system (202) includes an evaporator (301), a compressor (302), a condenser (303), and an expansion valve (304). The evaporator (301) is connected to the shell (102) through a gas outlet pipe and has two outlets: decarbonized air and condensate. The condenser (303) is connected to the filter (105) and the aging device (203) through pipes.

3. The direct air carbon capture system according to claim 1, characterized in that: The biomass carbon material gas absorption plate (103) is prepared from biomass raw materials with natural porous structure through freezing, carbonization and molding processes. The biomass raw materials used include, but are not limited to, plant trunks, roots, leaves and fruits. In addition to being made into a plate shape, the original shape of the biomass carbon material can also be made into a tube shape and then processed into an arch shape.

4. A carbon capture method for an airborne carbon capture system according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: The lean liquid is drawn from the lean liquid tank (101) into the biomass carbon material gas absorption plate (103) through capillary action and siphon phenomenon, and is uniformly adsorbed in the pore structure of the biomass carbon material gas absorption plate (103), and reacts with CO2 in the air introduced from the gas inlet of the shell (102) to generate rich liquid. Step 2: The rich solution is transferred to the particle reaction tank (104) under the siphon effect and the ion concentration difference. In the particle reaction tank (104), it reacts with Ca(OH)2 to generate a precipitate. The precipitate enters the filter (105). The filtered liquid phase is the regenerated lean solution. The lean solution is returned to the lean solution tank (101) through the solution pump (106). Step 3: The solids produced by the filter (105) are preheated in the heat pump system condenser (303) for the first stage, then preheated in the curing tank (203) for the second stage, and finally enter the calcining furnace (204). The CO2 is desorbed by calcination in the calcining furnace (204). The CO2 released by calcination is condensed in the condenser separator (205) and then compressed by the CO2 compressor (206) to obtain high-concentration CO2. The high-concentration CO2 can be used for physical, chemical, biological, geological utilization, or geological sequestration. Step 4: The CaO generated from calcining CaCO3 in the calcining furnace (204) enters the ripening device (203) and reacts with water to generate Ca(OH)2 slurry. This slurry enters the particle reaction tank (104) and reacts with the rich liquor in the particle reaction tank (104) to achieve lean liquor regeneration. Step 5: The decarbonized air is discharged from the gas outlet pipe of the shell (102) into the heat pump system evaporator (301), where it is cooled to achieve gas-water separation. The gas is discharged and the water can be returned to the lean liquid tank (101) as a makeup liquid.

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