Carbon reduction apparatus and method

Abstract

The application provides a carbon reduction device and method. The carbon reduction device comprises a solid adsorption layer, a heat supply plate and an electrolysis unit. The solid adsorption layer is used for adsorbing carbon dioxide in air. The solid adsorption layer has a first side and a second side arranged oppositely. The heat supply plate is arranged on the first side and used for providing heat for desorption of carbon dioxide from the solid adsorption layer. The electrolysis unit is arranged on the second side and used for electrolytic reduction of the desorbed carbon dioxide from the solid adsorption layer. The carbon reduction device directly absorbs carbon dioxide from air and realizes in-situ electrochemical conversion, thereby avoiding the cost of air drying. In-situ carbon reduction conversion also enhances the concentration difference driving force of carbon capture, thereby improving the carbon capture efficiency. Furthermore, the carbon dioxide in air is directly converted into valuable products in the electrolysis unit, thereby avoiding the cost of carbon sequestration.

Description

Technical Field

[0001] This application relates to the field of carbon reduction technology, and in particular to a carbon reduction device and method. Background Technology

[0002] With the introduction of dual-carbon targets, carbon dioxide capture and utilization have received increasing attention. Direct air carbon capture, unrestricted by location or carbon source, is a promising technology. However, due to the low carbon dioxide content, direct air carbon capture suffers from high energy consumption and low capture efficiency, and post-capture carbon storage also presents certain challenges.

[0003] Carbon capture, storage, and utilization are also key issues in carbon reduction. While stored carbon dioxide cannot generate economic benefits, converting it into valuable products and utilizing it to form a carbon cycle is a more sustainable carbon reduction strategy. Using electrochemical methods to reduce carbon dioxide into organic products has the advantages of being environmentally friendly and simple; however, electrochemical carbon reduction often faces disadvantages such as low conversion efficiency and low selectivity. Furthermore, in aqueous electrochemical carbon reduction, the presence of anion exchange membranes increases system costs. Summary of the Invention

[0004] In view of this, one object of this application is to provide a carbon reduction device that avoids the cost of air drying by directly absorbing carbon dioxide from the air and performing in-situ electrochemical conversion; the in-situ carbon reduction conversion also enhances the concentration drive of the capture, which helps to improve the capture efficiency; in addition, the direct conversion of carbon dioxide in the air into valuable products is realized in the electrolysis unit, avoiding the cost of carbon sequestration.

[0005] Another objective of this application is to provide a carbon reduction method.

[0006] To achieve the above objectives, a first aspect of this application provides a carbon reduction apparatus, comprising:

[0007] A solid adsorption layer for adsorbing carbon dioxide from the air, the solid adsorption layer having a first side and a second side disposed opposite to each other;

[0008] A heating plate, located on the first side, is used to provide heat for the desorption of carbon dioxide from the solid adsorption layer.

[0009] An electrolysis unit is installed on the second side for electrolyzing and reducing the carbon dioxide desorbed from the solid adsorption layer.

[0010] In some embodiments, the adsorption material of the solid adsorption layer includes at least one of solid amine adsorbent and metal-organic framework material.

[0011] In some embodiments, the thickness of the solid adsorption layer is 0.1-1 mm.

[0012] In some embodiments, the solid adsorption layer further has an inlet side for air before carbon dioxide is adsorbed and an outlet side for air after carbon dioxide is adsorbed, wherein the inlet side and the outlet side are both arranged perpendicularly to the first side and the second side.

[0013] In some embodiments, the air intake side and the air outlet side are arranged opposite to each other.

[0014] In some embodiments, the air intake side is connected to a blower for forcing air to flow through the solid adsorption layer before carbon dioxide is adsorbed.

[0015] In some embodiments, the blowing volume of the blower is such that the air transfer velocity within the solid adsorption layer before carbon dioxide is adsorbed is 4-10 m / s.

[0016] In some embodiments, the air intake side is provided with an air inlet, and a gas distributor is provided at the air inlet.

[0017] In some embodiments, the solid adsorption layer is in close contact with the heating plate.

[0018] In some embodiments, the heating plate is one of a solar collector, an electric heating plate, or a flat plate heat exchanger.

[0019] In some embodiments, the heating plate is a solar collector plate, which includes a solar energy absorbing material layer and a sealing layer arranged sequentially; the solar energy absorbing material layer is adjacent to the solid adsorption layer.

[0020] In some embodiments, the material of the solar energy absorbing material layer includes at least one of titanium oxide, aluminum oxide, boron oxide, and perovskite thin film.

[0021] In some embodiments, the thickness of the solar energy absorbing material layer is 2-10 μm.

[0022] In some embodiments, the material of the sealing layer includes at least one of polydimethylsiloxane, polymethyl methacrylate, polycarbonate, polypropylene, and polyvinyl chloride.

[0023] In some embodiments, the thickness of the sealing layer is 1-2 mm.

[0024] In some embodiments, the electrolysis unit is a diaphragmless electrolytic cell.

[0025] In some embodiments, the electrolysis unit includes an electrolysis cell body and a cathode, an anode, and an electrolyte disposed within the electrolysis cell body; the electrolysis cell body is a container with an opening on one side, and the end of the opening side is sealed to the second side surface of the solid adsorption layer.

[0026] In some embodiments, the surface of the electrolyte contacts the second side surface of the solid adsorption layer.

[0027] In some embodiments, the electrolyte is an alkaline electrolyte.

[0028] In some embodiments, the electrolyte contains a substrate for the anodic reaction.

[0029] In some embodiments, the cathode is located adjacent to the solid adsorption layer, and the anode is located on the side of the cathode away from the solid adsorption layer.

[0030] In some embodiments, the cathode is a carbon dioxide reduction reaction electrode.

[0031] In some embodiments, the anode is a metal oxide-based electrode.

[0032] To achieve the above objectives, a second aspect of this application provides a method for carbon reduction, comprising:

[0033] The solid adsorption layer adsorbs carbon dioxide from the air;

[0034] The carbon dioxide adsorbed by the solid adsorption layer is desorbed upon heating;

[0035] The desorbed carbon dioxide enters the electrolytic cell and is absorbed by the electrolyte, subsequently undergoing a carbon reduction reaction.

[0036] In some embodiments, the carbon reduction method further includes: adding an electrolyte to the reaction system during the carbon reduction reaction.

[0037] The carbon reduction apparatus of this application has at least the following beneficial effects:

[0038] 1. Air carbon capture is achieved through solid adsorption, eliminating the need for air drying.

[0039] 2. Carbon dioxide consumption is achieved in the electrolysis unit, which provides a driving force for gas adsorption and synergistically enhances process efficiency.

[0040] 3. By setting up the electrolyte, cathode, anode, and reaction substrate, different types of carbon reduction reactions can occur in the electrolysis unit, thereby achieving diversified application paths.

[0041] 4. Using solar collectors and other heating panels to provide desorption heat to the solid adsorption layer is green and environmentally friendly.

[0042] 5. The electrolysis unit adopts a diaphragm-free electrolytic cell, which can further reduce the cost of carbon reduction compared to the existing aqueous electrochemical carbon reduction with anion exchange diaphragms.

[0043] 6. The electricity used for carbon reduction in the electrolysis unit can come from clean energy sources such as photovoltaic power generation and wind power.

[0044] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0045] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0046] Figure 1 This is a schematic diagram of the structure of a carbon reduction device shown in an exemplary embodiment of this application.

[0047] Figure 2 This is a schematic diagram of the structure of a carbon reduction device shown in another exemplary embodiment of this application.

[0048] Figure label:

[0049] 1-Solid adsorption layer; 101-First side; 102-Second side; 103-Inlet side; 104-Outlet side; 2-Heating plate; 201-Solar energy absorption material layer; 202-Sealing layer; 3-Electrolysis unit; 301-Electrolysis cell body; 302-Cathode; 303-Anode; 4-Blower; 5-Sealing bonding surface. Detailed Implementation

[0050] The embodiments of this application are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0051] In the application, the disclosure of the numerical range includes all values ​​throughout the range and the disclosure of further subdivisions of the range, including the endpoints and subranges given for these ranges.

[0052] Unless otherwise specified, all raw materials and equipment involved in the application are those that can be manufactured commercially or by known methods; and all methods involved are conventional methods unless otherwise specified.

[0053] A carbon reduction apparatus and a carbon reduction method according to embodiments of this application are described below with reference to the accompanying drawings.

[0054] Figure 1This is a schematic diagram of the structure of a carbon reduction device shown in an exemplary embodiment of this application.

[0055] like Figure 1 As shown, the carbon reduction device in this embodiment includes a solid adsorption layer 1, a heating plate 2, and an electrolysis unit 3.

[0056] The solid adsorption layer 1 is used to adsorb carbon dioxide in the air. The solid adsorption layer 1 has a first side 101 and a second side 102 disposed opposite to each other.

[0057] The heating plate 2 is located on the first side 101 and is used to provide heat for the desorption of carbon dioxide from the solid adsorption layer 1.

[0058] Electrolysis unit 3 is installed on the second side 102 and is used to electrolyze and reduce the carbon dioxide desorbed from the solid adsorption layer 1.

[0059] The carbon reduction apparatus of this application avoids the cost of air drying by directly absorbing carbon dioxide from the air and performing in-situ electrochemical conversion; the in-situ carbon reduction conversion also enhances the concentration drive of the capture, which helps to improve the capture efficiency; in addition, the direct conversion of carbon dioxide in the air into valuable products is realized in the electrolysis unit, avoiding the cost of carbon sequestration.

[0060] In some embodiments, the solid adsorption layer 1 is tightly attached to the heating plate 2.

[0061] It should be noted that in the embodiments of this application, the solid adsorption layer is closely attached to the heating plate, including but not limited to the first side surface of the solid adsorption layer being in direct surface contact with the surface of the heating plate only through the placement position, and the first side surface of the solid adsorption layer being connected to the surface of the heating plate by means of hot pressing, adhesive bonding, etc., so that the two are closely attached, etc.

[0062] In some embodiments, the heating plate 2 includes, but is not limited to, a solar collector plate, an electric heating plate, or a flat plate heat exchanger. When a flat plate heat exchanger is selected, it can simply be a flat, hollow container in which a hot coal medium, such as hot flue gas, hot water, or hot oil, circulates.

[0063] As a possible example, the heating panel 2 is a solar collector panel, which includes a solar absorber material layer 201 and a sealing layer 202 arranged sequentially; the solar absorber material layer 201 is adjacent to the solid adsorption layer 1. That is, the sealing layer 202 is provided on one side of the solar absorber material layer, and the aforementioned solid adsorption layer 1 is provided on the other side. The sealing layer can isolate convective heat dissipation and improve the collection efficiency of carbon dioxide gas.

[0064] In some embodiments, the solar energy absorbing material layer 201 and the sealing layer 202 are connected by overlapping and close contact, hot pressing, ultrasonic welding, etc.

[0065] In some embodiments, the material of the solar energy absorbing material layer 201 includes at least one of titanium oxide, aluminum oxide, boron oxide, and perovskite film, such as titanium oxide plate, aluminum oxide plate, boron oxide plate, etc.

[0066] In some embodiments, the thickness of the solar energy absorbing material layer 201 is 2-10 μm, including but not limited to 2 μm, 5 μm, 7 μm, 9 μm, or 10 μm. If the thickness of the solar energy absorbing material layer is too large, it will lead to a decrease in the solar energy absorption rate per unit material and a reduction in the heat transfer rate; if the thickness of the solar energy absorbing material layer is too small, it will lead to insufficient overall heat absorption and will not achieve a good carbon dioxide heating and release effect.

[0067] In some embodiments, the material of the sealing layer 202 includes at least one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polycarbonate (PC), polypropylene (PP), and polyvinyl chloride (PVC).

[0068] In some embodiments, the thickness of the sealing layer 202 is 1-2 mm, including but not limited to 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, or 2 mm. If the thickness of the sealing layer is too low, the heat convection blocking effect will be poor, resulting in more heat dissipation; if the thickness of the sealing layer is too high, it will block sunlight to some extent, reducing the sunlight absorption rate of the underlying absorbing material.

[0069] In some embodiments, the adsorption material of the solid adsorption layer 1 includes, but is not limited to, at least one of solid amine adsorbents and metal-organic framework materials. As non-limiting examples, solid amine adsorbents include, but are not limited to, at least one of polyethyleneimine (PEI)-supported porous carbon, tetraethylenepentamine (TEPA)-supported SBA-15 (SBA-15 is a type of mesoporous molecular sieve), and polyethyleneimine (PEI)-supported mesoporous alumina; metal-organic framework (MOF) materials include, but are not limited to, at least one of MOF-177, MOF-5, IRMOF-1, SIFSIX-3-Ni, SIFSIX-3-Cu, NbOFFIVE-1-Ni, and ZIF-8 / chitosan-polyacrylamide hydrogel composites. In the embodiments of this application, the solid adsorption layer can collect carbon dioxide from the air through physical adsorption.

[0070] As a possible example, the adsorbent material of the solid adsorbent layer is a ZIF-8 / chitosan-polyacrylamide hydrogel composite, which is synthesized as follows: a certain amount of chitosan (CS) is added to a 2% acetic acid solution to make the mass concentration of CS 5-15 g / L, and then a certain amount of hexadecyltrimethylammonium bromide (CTAB) is added, the mass of CTAB being 1 / 3 of that of CS. The mixture is stirred thoroughly to obtain a CS solution. A 50 g / L solution of ammonium persulfate (APS) with 1 / 3 CS mass was prepared in pure water and stirred until homogeneous. The prepared APS solution was then added. Next, 1 / 6 volume of acrylic acid was added to the APS solution. Then, a 12 g / L solution of N,N'-methylenebisacrylamide (BIS) with 1 / 12 CS mass was prepared in pure water and stirred until homogeneous. This solution was then added to the prepared APS solution. The mixture was stirred at 70°C for 4 hours under a vacuum nitrogen atmosphere to obtain chitosan-polyacrylic acid gel. The chitosan-polyacrylic acid gel was then sequentially immersed in a methanol solution of Zn(NO3)2 and a methanol solution of 2-methylimidazole (2-MeIM), and stirred at 60°C for at least 4 hours each time. The Zn... 2+ The molar ratio of Zn to 2-MeIM is 1:8. 2+ The concentration was 0.6 mol / L, allowing ZIF-8 to grow in situ on the gel surface. The product was washed three times with methanol and water, and then vacuum dried at 50°C for more than 12 hours to obtain ZIF-8 / chitosan-polyacrylic acid hydrogel. During the synthesis process, the thickness of the solid adsorbent layer was controlled within the range specified in this application embodiment by controlling the thickness of the gel layer before drying and molding.

[0071] In some embodiments, the thickness of the solid adsorption layer 1 is 0.1-1 mm, including but not limited to 0.1 mm, 0.3 mm, 0.5 mm, 0.8 mm, or 1 mm. A thickness within the above range allows the solid adsorption layer to achieve both high carbon dioxide adsorption and transfer rates, while also having a high adsorption capacity. This fully utilizes solar energy or other heat sources provided by the heating plate, thereby improving the efficiency of the carbon reduction reaction.

[0072] In some embodiments, the solid adsorption layer 1 further has an inlet side 103 for air before carbon dioxide is adsorbed and an outlet side 104 for air after carbon dioxide is adsorbed, both the inlet side 103 and the outlet side 104 being arranged perpendicularly to the first side 101 and the second side 102.

[0073] It is understandable that as long as the intake side 103 and the exhaust side 104 are both perpendicular to the first side 101 and the second side 102, the relative positions of the intake side and the exhaust side are not limited, and can be adjacent or opposite.

[0074] However, in order to extend the airflow path within the solid adsorption layer and ensure that as much carbon dioxide as possible in the air is adsorbed by the solid adsorption layer, as a possible example, the air inlet side 103 and the air outlet side 104 are arranged opposite each other.

[0075] It should be noted that in the embodiments of this application, the specific positions of the first side, the second side, the air intake side, and the air outlet side are not limited, as long as they conform to the positional relationship between them. For example, as Figure 1 As shown, when the carbon reduction device is placed horizontally, the first side 101 refers to the upper side of the solid adsorption layer 1, the second side 102 refers to the lower side of the solid adsorption layer 1, the inlet side 103 refers to the left side of the solid adsorption layer 1, and the outlet side 104 refers to the right side of the solid adsorption layer 1.

[0076] In the embodiments of this application, the structure of the solid adsorption layer can exist in at least one of the following ways:

[0077] The first type: The solid adsorption layer is only a material layer composed of the adsorption material itself;

[0078] The second type: A shell layer is provided in the part of the solid adsorption layer other than the first side, the second side, the air inlet side and the air outlet side to cover the solid adsorption layer (for example, when the solid adsorption layer is cuboid and the first side is the top side, the second side is the bottom side, the air inlet side is the left side and the air outlet side is the right side, the shell layer covers the front and rear sides of the solid adsorption layer).

[0079] The third type: A shell is provided on all parts of the solid adsorption layer except for the first side and the second side to cover the solid adsorption layer (for example, when the solid adsorption layer is cuboid and the first side is the upper side and the second side is the lower side, the shell covers the entire sidewall of the solid adsorption layer - the air inlet side (front side), the air outlet side (rear side), the left side and the right side), and the air inlet side 103 and the air outlet side 104 are respectively provided with an air inlet and an air outlet.

[0080] All three methods can achieve the goal of adsorbing carbon dioxide from the air through the solid adsorption layer, and then releasing it from the solid adsorption layer. Compared with the first method, the second and third methods can better ensure that air enters from the inlet side and exits from the outlet side; however, compared with the third method, the air distribution entering the solid adsorption layer is more uniform in the second method, while the uniformity of air distribution entering the solid adsorption layer is slightly worse in the third method due to the presence of both inlet and outlet.

[0081] Therefore, as Figure 2As shown, in some embodiments, to ensure that air enters the solid adsorption layer from the inlet side more effectively before carbon dioxide is adsorbed, and that air exits the solid adsorption layer from the outlet side more effectively after carbon dioxide is adsorbed, for the solid adsorption layer in the above three methods in the embodiments of this application, a blower 4 for driving the air before carbon dioxide adsorption to flow through the solid adsorption layer 1 can be connected to the inlet side 103. In this way, on the one hand, the blower drives the air to flow from the inlet side to the outlet side through the solid adsorption layer, adsorbing the carbon dioxide therein, and the contact between the air and each part of the solid adsorption layer is relatively uniform; on the other hand, by setting the blower volume, the boundary layer resistance of heat transfer can be eliminated, and the transfer speed of carbon dioxide to the electrolysis unit can be improved; in addition, the setting of the blower can also provide sufficient carbon dioxide adsorption substrate for the solid adsorption layer.

[0082] As a non-limiting example, the blower device 4 includes, but is not limited to, one of a centrifugal blower, a positive displacement blower, an axial flow blower, etc.

[0083] In some embodiments, the blowing volume of the blower 4 ensures that the air transfer velocity within the solid adsorption layer 1 before carbon dioxide adsorption is 4-10 m / s, including but not limited to 4 m / s, 6 m / s, 8 m / s, or 10 m / s. When the blowing volume of the blower ensures that the air transfer velocity within the solid adsorption layer before carbon dioxide adsorption is within the above range, it can eliminate the boundary layer resistance of solar heat transfer when a solar collector is selected as the heating plate, and improve the transfer velocity of carbon dioxide to the electrolysis unit. If the transfer velocity is too low, the improvement effect of ensuring air enters from the inlet side and exits from the outlet side is not significant; if the transfer velocity is too high, the air flows through the solid adsorption layer too quickly, and some carbon dioxide may be discharged with the air before being adsorbed, reducing the content of carbon dioxide participating in carbon reduction, reducing the amount of recovered products, and causing carbon emissions.

[0084] As a possible example, when the third form described above is adopted—when a shell for covering the solid adsorption layer is provided in all parts of the solid adsorption layer except for the first and second sides, and an air inlet and an air outlet are respectively provided on the air inlet side 103 and the air outlet side 104, or when a blower 4 is connected to the air inlet at the same time, a gas distributor for uniformly distributing the air from the air inlet on the air inlet side is provided at the air inlet.

[0085] It should be noted that the electrolysis unit in the carbon reduction apparatus of this application embodiment can be a conventional diaphragm-based electrolytic cell or a diaphragm-less electrolytic cell. However, in order to reduce costs, in some embodiments, the electrolysis unit uses a diaphragm-less electrolytic cell, and the structure of the diaphragm-less electrolytic cell is not limited.

[0086] As a non-limiting example, the electrolysis unit 3 in this embodiment employs a diaphragm-free electrolytic cell, which includes an electrolytic cell body 301 and a cathode 302, an anode 303, and an electrolyte disposed within the electrolytic cell body 301; the electrolytic cell body 301 is a container with an opening on one side, and its opening end is sealed to the surface of the second side 102 of the solid adsorption layer 1, and the contact area between the two can become a sealing bonding surface 5 (e.g., Figure 1 and Figure 2 (As shown).

[0087] In some embodiments, the material of the electrolytic cell body 301 includes, but is not limited to, stainless steel, transparent or translucent plastic, wherein the transparent or translucent plastic includes, but is not limited to, polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA, commonly known as acrylic or plexiglass).

[0088] In some embodiments, the surface of the electrolyte contacts the surface of the second side 102 of the solid adsorption layer 1. The purpose of this design is to enable the alkaline electrolyte to absorb the carbon dioxide removed from the surface of the second side 102, thereby enhancing the mass transfer of carbon dioxide from the solid adsorption layer to the electrolyte and thus enhancing the mass transfer within the solid adsorption layer.

[0089] In some embodiments, the electrolyte is an alkaline electrolyte, such as a 20-30 wt% KOH solution.

[0090] In some embodiments, the electrolyte contains, in addition to an alkaline electrolyte, a substrate for the anodic reaction. The substrate for the anodic reaction includes, but is not limited to, at least one of ethylene glycol, methanol, and heteroaromatic hydrocarbons (bispyridine, tripyridine, pyrimidine, pyrazine, quinoline, etc.). In the embodiments of this application, different types of carbon reduction reactions occur in the electrolysis unit through the design of the reaction process and the reaction substrate.

[0091] In some embodiments, the content of the anodic reaction substrate in the electrolyte is 0.1-0.5M, including but not limited to 0.1M, 0.2M, 0.3M, 0.4M or 0.5M.

[0092] In some embodiments, the cathode 302 is adjacent to the solid adsorption layer 1, and the anode 303 is provided on the side of the cathode 302 away from the solid adsorption layer 1. It should be noted that in the embodiments of this application, the closer the cathode is to the solid adsorption layer, the better. The reason is that the proximity of the cathode to the solid adsorption layer can shorten the mass transfer path of carbon dioxide in the electrolyte, and the process of carbon dioxide being transferred to the cathode surface is faster, thereby enhancing the carbon dioxide reduction reaction at the cathode. The distance between the anode and the cathode is not limited, as long as it is ensured that the surface of the anode away from the solid adsorption layer does not contact the electrolytic cell body.

[0093] In some embodiments, the cathode 302 is a carbon dioxide reduction reaction electrode, including but not limited to one of a Pb electrode, Hg electrode, Tl electrode, In electrode, Sn electrode, Cd electrode, Ni electrode, and Cu electrode.

[0094] In some embodiments, the anode 303 is a metal oxide-based electrode, including but not limited to one of an Ir oxide electrode, a Ru oxide electrode, a composite nickel-based metal oxide electrode, etc.

[0095] In some embodiments, the specific installation method of the cathode 302 and anode 303 in the electrolytic cell body 301 is not limited, including but not limited to solid mounting with a bracket, or fixing by engaging with a groove provided on the side wall of the electrolytic cell body.

[0096] The method for carbon reduction using the carbon reduction apparatus of this application (i.e., the working method of the carbon reduction apparatus of this application) includes the following steps:

[0097] S101, Solid adsorption layer 1 adsorbs carbon dioxide from the air.

[0098] S102. Carbon dioxide adsorbed by solid adsorption layer 1 is desorbed upon heating.

[0099] Carbon dioxide adsorbed in the solid adsorption layer is desorbed from the solid adsorption layer by the heating plate.

[0100] In some embodiments, the temperature at which carbon dioxide adsorbed by the solid adsorption layer is desorbed by heat is 25-60°C, including but not limited to 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C.

[0101] It should be noted that in the embodiments of this application, the adsorption and thermal desorption of carbon dioxide from the air by the solid adsorption layer occur simultaneously. Since carbon dioxide is continuously consumed on the side below the adsorption layer near the electrolytic cell, the resulting concentration gradient perpendicular to the direction of the adsorption layer provides a high mass transfer drive for carbon dioxide, so that the adsorption, desorption, and transfer of carbon dioxide are in dynamic equilibrium. Under steady state, the adsorption, desorption, and transfer rates are unified within an appropriate temperature range, providing sufficient reaction substrate for the electrolytic cell.

[0102] S103. The desorbed carbon dioxide enters the electrolytic cell and is absorbed by the electrolyte, followed by a carbon reduction reaction.

[0103] The carbon dioxide is transferred from the side containing the solid adsorption layer to the side of the electrolysis unit (for example, when the heating plate, solid adsorption layer, and electrolysis unit are arranged sequentially from top to bottom, i.e., the desorbed carbon dioxide is transferred from top to bottom). When it comes into contact with the concentrated alkaline solution (e.g., the aforementioned 20-30 wt% KOH solution) on the surface of the solid adsorption layer away from the heating plate (i.e., the second side 102 mentioned above), it is absorbed by the concentrated alkaline solution; the carbon dioxide reacts on the cathode surface, for example:

[0104] CO2 + H2O + 2e - —>HCOOH+OH -

[0105] On the anode surface, the anodic reaction substrate undergoes an oxidation reaction, producing the same products, such as:

[0106] 6OH - +C2H4(OH)2——>2HCOOH+4H2O+2e - .

[0107] In some embodiments, the process conditions for the carbon reduction reaction are: a reaction voltage of 1-5V and a current density of 10-500mA / cm². 2 The reaction temperature is 25-80℃.

[0108] As a non-limiting example, the reaction voltage for carbon reduction reactions includes, but is not limited to, 1V, 2V, 3V, 4V, or 5V, and the current density includes, but is not limited to, 10mA / cm². 2 50mA / cm 2 100mA / cm 2 200mA / cm 2 300mA / cm 2 400mA / cm 2 Or 500mA / cm 2 The reaction temperature includes, but is not limited to, 25℃, 30℃, 40℃, 50℃, 60℃, 70℃ or 80℃.

[0109] In some embodiments, to ensure the continuity of the reaction, the carbon reduction method further includes the step of adding an electrolyte to the reaction system during the carbon reduction reaction. That is, the carbon reduction method also includes the step of adding an alkaline solution and an anolyte to the reaction system during the carbon reduction reaction.

[0110] The following non-limiting embodiments further illustrate certain features of the present technology.

[0111] like Figure 2 As shown, the carbon reduction device of this embodiment includes a solid adsorption layer 1, a heating plate 2, and an electrolysis unit 3 arranged sequentially from top to bottom.

[0112] The solid adsorption layer 1, which adsorbs carbon dioxide from the air, is rectangular in shape. Its upper surface (the surface of the first side 101) is tightly attached to the heating plate 2, which provides heat for the desorption of carbon dioxide from the solid adsorption layer 1. In this embodiment, a solar collector plate is used. The lower surface of the solid adsorption layer 1 (the surface of the second side 102) is sealed to the electrolysis unit 3, which is used to electrolyze and reduce the carbon dioxide desorbed from the solid adsorption layer 1. In this embodiment, a diaphragm-free electrolysis cell is used. The left side of the solid adsorption layer 1 is the air inlet side 103, and the right side is the air outlet side 104.

[0113] A blower 4 is provided on the left side of the solid adsorption layer 1 to force air to flow through the solid adsorption layer 1 before carbon dioxide is adsorbed. The exhaust port of the blower 4 is directly opposite the middle part of the left side of the solid adsorption layer 1, and the distance between the two is 1 cm. The blower 4 is a volumetric blower. In this way, on the one hand, the blower drives the air to flow from the air inlet side to the air outlet side through the solid adsorption layer, adsorbing the carbon dioxide therein, and the air contact with all parts of the solid adsorption layer is relatively uniform; on the other hand, by setting the air volume of the blower, the boundary layer resistance of solar heat transfer can be eliminated, and the transfer speed of carbon dioxide to the electrolysis unit can be improved; in addition, the setting of the blower can also provide sufficient carbon dioxide adsorption substrate for the solid adsorption layer.

[0114] Solid adsorption layer 1 is a ZIF-8 / chitosan-polyacrylamide hydrogel composite, and its synthesis method is as follows:

[0115] A certain mass (e.g., 12 g) of chitosan (CS) is added to a 2 wt% acetic acid solution to make the mass concentration of CS 5-15 g / L. Then, a certain amount of hexadecyltrimethylammonium bromide (CTAB) is added, with the mass of CTAB being 1 / 3 of that of CS. The mixture is stirred thoroughly to obtain a CS solution. A 50 g / L solution of ammonium persulfate (APS) with 1 / 3 CS mass was prepared in pure water and stirred until homogeneous. The prepared CS solution was then added. Next, 1 / 6 volume of acrylic acid was added to the CS solution to obtain a mixed solution. Then, a 12 g / L solution of N,N'-methylenebisacrylamide (BIS) with 1 / 12 CS mass was prepared in pure water and stirred until homogeneous. This solution was then added to the aforementioned mixed solution. The mixture was stirred at 70°C for 4 hours under a vacuum nitrogen atmosphere to obtain chitosan-polyacrylic acid gel. The chitosan-polyacrylic acid gel was then sequentially immersed in a methanol solution of Zn(NO3)2 and a methanol solution of 2-methylimidazole (2-MeIM), and stirred at 60°C for at least 4 hours (e.g., 6 hours). The Zn... 2+ The molar ratio of Zn to 2-MeIM is 1:8. 2+The concentration was 0.6 mol / L, allowing ZIF-8 to grow in situ on the gel surface. The product was washed three times with methanol and deionized water, and then vacuum dried at 50°C for at least 12 hours (e.g., 15 hours) to obtain ZIF-8 / chitosan-polyacrylic acid hydrogel. During the synthesis process, the thickness of the solid adsorption layer was controlled within the range specified in this embodiment of the application by controlling the thickness of the gel layer before drying and molding. The resulting gel thickness was 0.2 mm. The adsorption rate of the solid adsorption layer for carbon dioxide was 0.12 mmol (CO2) / g (adsorbent) / min, which was achieved when the solar power reached 2 W / cm². 2 When the average residence time of air through the solid adsorption layer reaches 0.5 h and the surface flow velocity reaches 4 m / s, a carbon dioxide absorption rate of over 80% and a carbon dioxide release rate of 0.1 mmol (CO2) / g (adsorbent) / min can be obtained.

[0116] As mentioned earlier, the heating panel 2 is a solar collector panel, which includes a solar absorption material layer 201 and a sealing layer 202 arranged sequentially from top to bottom. The lower surface of the solar absorption material layer 201 is tightly attached to the lower surface of the solid adsorption layer 1. The sealing layer can isolate convective heat dissipation and improve the collection efficiency of carbon dioxide gas. It is connected to the solar absorption material layer 201 by hot pressing. The solar absorption material layer 201 is a titanium oxide plate with a thickness of 5 μm. The sealing layer 202 is made of polydimethylsiloxane (PDMS) with a thickness of 1.5 mm.

[0117] As described above, the electrolysis unit 3 employs a diaphragm-free electrolytic cell, which includes an electrolytic cell body 301 and a cathode 302, an anode 303, and an electrolyte disposed within the electrolytic cell body 301. The electrolytic cell body 301 is a cuboid container with a top opening (completely open), and its top is sealed to the lower surface of the solid adsorption layer 1 at the location directly opposite the side wall of the electrolytic cell body. The contact area between the two can serve as a sealing bonding surface 5 (e.g., Figure 2 (As shown).

[0118] The electrolytic cell body 301 is made of polytetrafluoroethylene (PTFE). The electrolytic cell body 301 is equipped with an electrolyte replenishment port (alkali solution and anolyte products) and a product collection port. The electrolyte consists of a 25 wt% KOH solution and ethylene glycol, the anolyte substrate, with a content of 0.1-0.5 M (e.g., 0.3 M) in the electrolyte. The electrolyte surface contacts the lower surface of the solid adsorption layer 1.

[0119] Both cathode 302 and anode 303 are arranged parallel to the solid adsorption layer 1 and the heating plate 2, with cathode 302 positioned above anode 303. Cathode 302 is adjacent to the solid adsorption layer 1, with a distance of 1 mm between them. A gap is left between the lower surface of anode 303 and the bottom of the electrolytic cell body 301, and the distance between anode 303 and cathode 302 is 1-5 cm (e.g., 3 cm). Both anode 303 and cathode 302 are fixedly connected to the front and rear sides of the electrolytic cell body 301 by engaging with slots on the front and rear walls, respectively. Gaps are also left between the left and right sides of anode 303 and cathode 302 and the left and right walls of the electrolytic cell body 301. Cathode 302 is a Sn electrode, and anode 303 is an Ir oxide electrode.

[0120] The working method (i.e., carbon reduction method) of the carbon reduction device in this embodiment is as follows:

[0121] Solid adsorption layer 1 adsorbs carbon dioxide from the air. Under the heating action of the solar collector plate 2, the carbon dioxide desorbs from solid adsorption layer 1 and is transferred from top to bottom. When it comes into contact with the concentrated alkaline solution (25wt% KOH solution) on the lower surface of solid adsorption layer 1, it is absorbed by the concentrated alkaline solution. The carbon dioxide reacts on the cathode surface, for example:

[0122] CO2 + H2O + 2e - —>HCOOH+OH -

[0123] On the anode surface, the anodic reaction substrate undergoes an oxidation reaction, producing the same products, such as:

[0124] 6OH - +C2H4(OH)2——>2HCOOH+4H2O+2e - .

[0125] The process conditions for the carbon reduction reaction are as follows: reaction voltage of 1.8-2.2V (e.g., 2V) and current density of 10-50mA / cm². 2 (For example, 30mA / cm) 2 The reaction temperature is 25℃.

[0126] During the reaction, 25wt% KOH solution and ethylene glycol, the substrate for the anolyte reaction, need to be added to the system. The standard for replenishment is to replenish the amount of hydroxide ions and ethylene glycol consumed, and to maintain the concentrations of KOH and ethylene glycol within the optimal range during the continuous reaction.

[0127] It should be noted that different types of carbon reduction reactions can occur in the electrolysis unit through the design of reactants and reaction processes. Besides formic acid production mentioned above, at least the following reactions can also occur in a diaphragm-less electrolyzer:

[0128] (1) Production of dimethyl carbonate: Reference: Redox-neutral electrochemical conversion of CO2 to dimethyl carbonate.

[0129] (2) Pharmaceuticals: Reference Electrochemical reactor dictates site selectivity in N-heteroarene carboxylations.

[0130] In summary, the carbon reduction apparatus and method of this application avoid the cost of air drying by directly absorbing carbon dioxide from the air and performing in-situ electrochemical conversion; the in-situ carbon reduction conversion also enhances the concentration gradient drive of the capture, which helps to improve the capture efficiency; in addition, the direct conversion of carbon dioxide in the air into valuable products is realized in the electrolysis unit, avoiding the cost of carbon sequestration.

[0131] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0132] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0133] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0134] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0135] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0136] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A carbon reduction apparatus, characterized in that, include: A solid adsorption layer for adsorbing carbon dioxide from the air, the solid adsorption layer having a first side and a second side disposed opposite to each other; A heating plate, located on the first side, is used to provide heat for the desorption of carbon dioxide from the solid adsorption layer. An electrolysis unit is installed on the second side and is used to electrolyze and reduce the carbon dioxide desorbed by the solid adsorption layer. The electrolysis unit is a membraneless electrolysis cell and includes an electrolysis cell body and a cathode, an anode and an electrolyte disposed within the electrolysis cell body. The electrolysis cell body is a container with one side open, and its open side end is sealed to the second side surface of the solid adsorption layer. The surface of the electrolyte contacts the second side surface of the solid adsorption layer; And / or, the cathode is located adjacent to the solid adsorption layer, and the anode is located on the side of the cathode away from the solid adsorption layer.

2. The carbon reduction apparatus according to claim 1, characterized in that, The adsorption material of the solid adsorption layer includes at least one of solid amine adsorbent and metal-organic framework material; And / or, the thickness of the solid adsorption layer is 0.1-1 mm.

3. The carbon reduction apparatus according to claim 1, characterized in that, The solid adsorption layer also has an inlet side for air before carbon dioxide is adsorbed and an outlet side for air after carbon dioxide is adsorbed, both of which are arranged perpendicularly to the first side and the second side.

4. The carbon reduction apparatus according to claim 3, characterized in that, The air intake side and the air outlet side are arranged opposite to each other; And / or, the air intake side is connected to a blower for forcing air to flow through the solid adsorption layer before carbon dioxide is adsorbed.

5. The carbon reduction apparatus according to claim 4, characterized in that, The blowing volume of the blower makes the air transfer velocity in the solid adsorption layer before carbon dioxide is adsorbed 4-10 m / s. And / or, the air intake side is provided with an air inlet, and a gas distributor is provided at the air inlet.

6. The carbon reduction apparatus according to claim 1, characterized in that, The solid adsorption layer is in close contact with the heating plate; And / or, the heating plate is one of a solar collector, an electric heating plate, or a flat plate heat exchanger.

7. The carbon reduction apparatus according to claim 6, characterized in that, The heating plate is a solar collector plate, which includes a solar energy absorption material layer and a sealing layer arranged in sequence; the solar energy absorption material layer is adjacent to the solid adsorption layer.

8. The carbon reduction apparatus according to claim 7, characterized in that, The material of the solar energy absorbing material layer includes at least one of titanium oxide, aluminum oxide, boron oxide, and perovskite thin film; And / or, the thickness of the solar energy absorbing material layer is 2-10 μm; And / or, the material of the sealing layer includes at least one of polydimethylsiloxane, polymethyl methacrylate, polycarbonate, polypropylene, and polyvinyl chloride; And / or, the thickness of the sealing layer is 1-2 mm.

9. The carbon reduction apparatus according to claim 1, characterized in that, The electrolyte is an alkaline electrolyte; And / or, the electrolyte contains a substrate for the anodic reaction; And / or, the cathode is a carbon dioxide reduction reaction electrode; And / or, the anode is a metal oxide-based electrode.

10. A method for carbon reduction using the carbon reduction apparatus as described in any one of claims 1 to 9, characterized in that, include: The solid adsorption layer adsorbs carbon dioxide from the air; The carbon dioxide adsorbed by the solid adsorption layer is desorbed upon heating; The desorbed carbon dioxide enters the electrolytic cell and is absorbed by the electrolyte, subsequently undergoing a carbon reduction reaction.

11. The carbon reduction method according to claim 10, characterized in that, The carbon reduction method further includes: Electrolyte is added to the reaction system during the carbon reduction reaction.

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