A system and method for multi-stage parallel carbon dioxide catalytic reduction hydrogenation reaction

Abstract

The present disclosure relates to a system and method for multi-stage parallel carbon dioxide catalytic reduction hydrogenation reaction, which can diffuse the hydrogenation reaction material into the whole reaction chamber after entering the reaction chamber, can improve the residence time of the hydrogenation reaction material in the photocatalyst reactor, and can improve the hydrogenation reaction effect of carbon dioxide. Furthermore, a plurality of catalyst arc-shaped sheets with photocatalysts attached to the side walls are arranged in the reaction chamber, so that the hydrogenation reaction material reacts on the side walls of the catalyst arc-shaped sheets, which can improve the total surface area of the hydrogenation reaction material in contact with the catalyst, and further improve the hydrogenation reaction efficiency and effect of carbon dioxide. Furthermore, a plurality of parallel photocatalytic reactors are arranged in the photocatalytic reactor group, so that the hydrogenation reaction material enters each photocatalytic reactor for hydrogenation reaction, which can improve the processing capacity of the hydrogenation reaction per unit time while ensuring the effect of the hydrogenation reaction.

Description

Technical Field

[0001] This disclosure relates to the field of carbon dioxide capture, and more specifically, to a system and method for a multi-stage parallel carbon dioxide catalytic reduction hydrogenation reaction. Background Technology

[0002] The widespread use of fossil fuels leads to massive emissions of carbon dioxide, exacerbating the greenhouse effect and severely impacting the global climate. Therefore, effectively reducing carbon dioxide concentrations has become a major concern. Current technologies often employ photocatalytic reduction to convert collected carbon dioxide and hydrogen produced from water electrolysis driven by renewable energy power generation into energy compounds.

[0003] However, CN206730862U in the prior art discloses a photocatalytic reduction reactor for carbon dioxide. The spiral reaction tube of this reactor is the main body for the reaction of carbon dioxide and hydrogen, and a photocatalyst is attached to the inner wall of the spiral reaction tube, which can convert carbon dioxide and hydrogen into energy compounds. However, when the hydrogenation reaction is carried out in this reactor, the hydrogenation reactants only flow in the spiral reaction tube and react with the photocatalyst attached to the inner wall. The hydrogenation reaction path is single and the hydrogenation reaction area is small. On the one hand, the light generated by the light source is blocked when it irradiates in the reactor, resulting in low light energy utilization. On the other hand, the total surface area of ​​the reactants in contact with the catalyst is small. Therefore, the efficiency and quality of the photocatalytic reaction are low. Summary of the Invention

[0004] The purpose of this disclosure is to provide a system and method for a multi-stage parallel carbon dioxide catalytic reduction hydrogenation reaction, in order to solve the problems of single reaction pathway, low light utilization, small total surface area of ​​hydrogenation reactants and catalysts, and inflexible reaction conditions in the prior art.

[0005] To achieve the above objectives, this disclosure provides a multi-stage parallel carbon dioxide catalytic reduction hydrogenation reaction system. The system includes a gas mixer, a photocatalytic reactor assembly, a blower, a liquid collector, and a gas collector. The photocatalytic reactor assembly includes multiple photocatalytic reactors arranged in parallel. Each photocatalytic reactor includes a cylindrical shell, a temperature regulating layer, a diffuse reflection layer, a catalyst arc-shaped thin plate assembly, and a tunable wavelength light source. The shell contains, from top to bottom, a feed chamber, a reaction chamber, and a discharge chamber. The temperature regulating layer covers the outside of the reaction chamber. The diffuse reflection layer, the catalyst arc-shaped thin plate assembly, and the tunable wavelength light source... The reaction chamber is arranged sequentially from the outside to the inside; the feed chamber and the discharge chamber are respectively provided with a feed inlet and a discharge outlet; the feed inlet is connected to the outlet of the gas mixer, and the discharge outlet is connected to the inlet of the blower; the top and bottom surfaces of the reaction chamber are respectively provided with through holes, so that the feed chamber and the discharge chamber are connected to the reaction chamber through the through holes; the catalyst arc-shaped thin plate assembly includes multiple catalyst arc-shaped thin plates, and the sidewalls of the catalyst arc-shaped thin plates are attached with photocatalysts; the upper and lower ends of the catalyst arc-shaped thin plates extend to the feed chamber and the discharge chamber respectively, and the concave surface of the arc-shaped thin plates faces the axis of the shell.

[0006] Optionally, the diffuse reflection layer is disposed on the inner wall of the temperature regulating layer; the adjustable wavelength light source is disposed inside the reaction chamber along the axial direction of the housing, preferably coaxially disposed with the reaction chamber; the adjustable wavelength light source includes one or more of xenon lamp light source, QTH adjustable quartz halogen lamp light source, deuterium lamp light source and halogen tungsten lamp light source.

[0007] Optionally, the surface of the catalyst arc-shaped thin plate extends along the axial direction of the shell, the catalyst arc-shaped thin plate is an arc-shaped thin plate of equal thickness and equal width at the top and bottom; the arc α of the arc-shaped thin plate is 20 to 30 rad and the thickness is 1 to 10 mm; multiple catalyst arc-shaped thin plates are arranged in parallel, and multiple catalyst arc-shaped thin plates are arranged at intervals along the same circumference on a plane perpendicular to the axial direction.

[0008] Optionally, the ratio of the height of the reaction chamber to the height of the shell is (0.5 to 0.7):1; the diameter of the through hole is 5 to 10 mm.

[0009] Optionally, the number of photocatalytic reactors in the photocatalytic reactor group is three or more.

[0010] Optionally, the system further includes a control unit and a carbon dioxide concentration detector disposed at the inlet of the photocatalytic reactor group; the control unit is electrically connected to the carbon dioxide concentration detector, the tunable wavelength light source in each of the photocatalytic reactors and the temperature regulation layer in each of the photocatalytic reactors, respectively, for receiving signals from the carbon dioxide concentration detector and adjusting the input power of the tunable wavelength light source and / or the temperature regulation layer in each of the photocatalytic reactors according to the signals.

[0011] The second aspect of this disclosure is a method for performing a carbon dioxide catalytic reduction hydrogenation reaction using the system described in the first aspect. The method includes: mixing carbon dioxide and hydrogen in a gas mixer to obtain hydrogenation reaction materials; introducing the hydrogenation reaction materials into each photocatalytic reactor and contacting them with the photocatalyst attached to the catalyst arc-shaped thin plate assembly to perform a hydrogenation reaction, thereby obtaining hydrogenation reaction products; and sequentially sending the hydrogenation reaction products from each photocatalytic reactor into a gas collector via a fan and a liquid collector.

[0012] Optionally, the photocatalyst comprises one or more of titanium dioxide particles, zinc oxide particles, and tin oxide particles.

[0013] Optionally, the conditions for the hydrogenation reaction include: a reaction temperature of 50–100°C, a reactant residence time of 5–10 s, and a light irradiance of 20–200 W / m² from a tunable wavelength light source. 2 .

[0014] Optionally, the method further includes a control unit adjusting the input power of the tunable wavelength light source and / or the temperature regulation layer in each photocatalytic reactor based on the concentration of carbon dioxide in the hydrogenation reactants and the number of photocatalytic reactors in the photocatalytic reactor group.

[0015] Through the above technical solution, a feed chamber is formed between the temperature regulation layer and the top of the shell of the photocatalytic reactor, a discharge chamber is formed between the temperature regulation layer and the bottom of the shell, and a reaction chamber is formed within the internal cavity of the temperature regulation layer. Furthermore, the reaction chamber is connected to the feed and discharge chambers through multiple through-holes, allowing the hydrogenation reactants to enter the reaction chamber through the through-holes after being buffered in the feed chamber, where they come into contact with the photocatalyst for hydrogenation. The hydrogenation reactants diffuse throughout the entire reaction chamber after entering, increasing their residence time in the photocatalytic reactor and thus improving the hydrogenation effect of carbon dioxide. Additionally, multiple arc-shaped catalyst plates with photocatalysts attached to their sidewalls are arranged in the reaction chamber, allowing the hydrogenation reactants to react on the sidewalls of these plates. This increases the total surface area of ​​contact between the hydrogenation reactants and the catalyst, thereby improving the efficiency and effect of carbon dioxide hydrogenation. Simultaneously, the inclusion of a diffuse reflection layer in the photocatalytic reactor allows light to be continuously reflected within a relatively small enclosed space, significantly improving light utilization and consequently enhancing the efficiency and effect of the photocatalytic reaction. Furthermore, the photocatalytic reactor group is equipped with multiple photocatalytic reactors connected in parallel, so that the hydrogenation reactants enter each photocatalytic reactor for hydrogenation reaction, which can increase the processing capacity per unit time of hydrogenation reaction while ensuring the effect of hydrogenation reaction.

[0016] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a schematic diagram of a cross-section of a photocatalytic reactor disclosed herein.

[0019] Figure 2 This is a top view of another photocatalytic reactor disclosed herein.

[0020] Figure 3 This is a schematic diagram of an arc-shaped thin plate of catalyst used in a photocatalytic reactor disclosed herein.

[0021] Figure 4 This is a schematic diagram of a multi-stage parallel carbon dioxide catalytic reduction hydrogenation system disclosed herein.

[0022] Figure 5 This is a schematic diagram of the photocatalytic reactor used in Comparative Example 1 of this disclosure.

[0023] Explanation of reference numerals in the attached figures

[0024] 1. Gas mixer; 2. Photocatalytic reactor group; 2-1. Primary photocatalytic reactor; 2-2. Secondary photocatalytic reactor; 2-3. Tertiary photocatalytic reactor; 2-4. Quaternary photocatalytic reactor; 2-5. Fifth-stage photocatalytic reactor; 2-6. Sixth-stage photocatalytic reactor; 3. Fan; 4. Liquid collector; 5. Gas collector; 9. Control unit; 20. Shell; 21. Temperature regulation layer; 22. Diffuse reflection layer; 23. Catalyst arc-shaped thin plate; 24. Tunable wavelength light source; 25. Feed chamber; 26. Discharge chamber; 27. Through hole; 29. ​​Heating layer; 30. Reflective layer; 31. Reaction tube; 32. Light source. Detailed Implementation

[0025] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0026] In this disclosure, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, for example, as shown in the reference. Figure 1 In the drawing orientation, "inner" and "outer" refer to those relative to the outline of the device. 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 one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] The first aspect of this disclosure provides a system for a multi-stage parallel carbon dioxide catalytic reduction hydrogenation reaction. The system includes a gas mixer 1, a photocatalytic reactor group 2, a blower 3, a liquid collector 4, and a gas collector 5. The photocatalytic reactor group 2 includes multiple photocatalytic reactors arranged in parallel. Each photocatalytic reactor includes a cylindrical shell 20, a temperature regulating layer 21, a diffuse reflection layer 22, a catalyst arc-shaped thin plate group, and a tunable wavelength light source 24. The shell 20 contains, from top to bottom, a feed chamber 25, a reaction chamber, and a discharge chamber 26. The temperature regulating layer 21 covers the outside of the reaction chamber. The diffuse reflection layer 22, the catalyst arc-shaped thin plate group, and the tunable wavelength light source 24 are arranged from the outside... The components are arranged sequentially inside the reaction chamber; the feed chamber 25 and the discharge chamber 26 are respectively provided with a feed inlet and a discharge outlet; the feed inlet is connected to the outlet of the gas mixer 1, and the discharge outlet is connected to the inlet of the blower 3; the top and bottom surfaces of the reaction chamber are respectively provided with through holes 27, so that the feed chamber 25 and the discharge chamber 26 are connected to the reaction chamber through the through holes 27; the catalyst arc-shaped thin plate assembly includes multiple catalyst arc-shaped thin plates 23, and the sidewalls of the catalyst arc-shaped thin plates 23 are attached with photocatalyst; the upper and lower ends of the catalyst arc-shaped thin plates 23 extend to the feed chamber 25 and the discharge chamber 26 respectively, and the concave surface of the arc-shaped thin plates faces the axis of the shell 20.

[0028] Through the above technical solution, a feed chamber is formed between the temperature regulation layer and the top of the shell of the photocatalytic reactor, a discharge chamber is formed between the temperature regulation layer and the bottom of the shell, and a reaction chamber is formed within the internal cavity of the temperature regulation layer. Furthermore, the reaction chamber is connected to the feed and discharge chambers through multiple through-holes, allowing the hydrogenation reactants to enter the reaction chamber through the through-holes after being buffered in the feed chamber, where they come into contact with the photocatalyst for hydrogenation. The hydrogenation reactants diffuse throughout the entire reaction chamber after entering, increasing their residence time in the photocatalytic reactor and thus improving the hydrogenation effect of carbon dioxide. Additionally, multiple arc-shaped catalyst plates with photocatalysts attached to their sidewalls are arranged in the reaction chamber, allowing the hydrogenation reactants to react on the sidewalls of these plates. This increases the total surface area of ​​contact between the hydrogenation reactants and the catalyst, thereby improving the efficiency and effect of carbon dioxide hydrogenation. Simultaneously, the inclusion of a diffuse reflection layer in the photocatalytic reactor allows light to be continuously reflected within a relatively small enclosed space, significantly improving light utilization and consequently enhancing the efficiency and effect of the photocatalytic reaction. Furthermore, the photocatalytic reactor group is equipped with multiple photocatalytic reactors connected in parallel, so that the hydrogenation reactants enter each photocatalytic reactor for hydrogenation reaction, which can increase the processing capacity per unit time of hydrogenation reaction while ensuring the effect of hydrogenation reaction.

[0029] The gas mixer used in this disclosure is a conventional choice in the art, and this application does not make any special requirements. For example, the gas mixer is generally cylindrical, with a hydrogen inlet and a carbon dioxide inlet on the top surface of the cylindrical body, and a mixed raw material gas outlet on the bottom surface of the cylindrical body; and multiple baffles are staggered inside the cylindrical body to make the hydrogen and carbon dioxide mix evenly under the action of the baffles.

[0030] In one embodiment, a first valve 6 is also provided on the outlet pipeline of the gas mixer 1 to control whether the hydrogenation reaction material enters the photocatalytic reactor group 2.

[0031] The fan used in this disclosure is a conventional choice in the art, and this application does not make any special requirements, as long as it can transport the hydrogenation reaction products in the photocatalytic reactor to the liquid collector 4.

[0032] The liquid collector 4 and gas collector used in this disclosure are conventional choices in the art, and this application does not make any special requirements. For example, the liquid collector 4 can be selected from a gas-liquid separation tower and / or a gas-liquid separation tank. In this embodiment, the liquid collector 4 includes a hydrogenation reaction product inlet, a liquid phase product outlet, and a separated gas phase outlet. The hydrogenation reaction product inlet of the liquid collector 4 is connected to the outlet of the blower 3 so that the hydrogenation reaction product can enter the liquid collector 4; the liquid phase product outlet of the liquid collector 4 is used to connect to a liquid phase product using device; the separated gas phase outlet of the liquid collector 4 is connected to the inlet of the gas collector so that the separated gas phase can be collected by the gas collector.

[0033] In one embodiment, the number of photocatalytic reactors in the photocatalytic reactor group 2 is three or more; for example, the number of photocatalytic reactors in the photocatalytic reactor group 2 is three, four, five or six.

[0034] In one specific embodiment, the photocatalytic reactor group 2 of this disclosure comprises six photocatalytic reactors: a primary photocatalytic reactor 2-1, a secondary photocatalytic reactor 2-2, a tertiary photocatalytic reactor 2-3, a quaternary photocatalytic reactor 2-4, a quinary photocatalytic reactor 2-5, and a sixth-stage photocatalytic reactor 2-6. The inlets of the primary photocatalytic reactor 2-1, the secondary photocatalytic reactor 2-2, the tertiary photocatalytic reactor 2-3, the quaternary photocatalytic reactor 2-4, the quinary photocatalytic reactor 2-5, and the sixth-stage photocatalytic reactor 2-6 are respectively connected to the outlet of the gas mixer 1. The outlets of the primary photocatalytic reactor 2-1, the secondary photocatalytic reactor 2-2, the tertiary photocatalytic reactor 2-3, the quaternary photocatalytic reactor 2-4, the quinary photocatalytic reactor 2-5, and the sixth-stage photocatalytic reactor 2-6 are respectively connected to the inlet of the fan 3.

[0035] In one embodiment, in order to allow for maintenance or shutdown of any photocatalytic reactor, a valve can be installed on the inlet pipeline of each photocatalytic reactor.

[0036] like Figure 1 and Figure 2 As shown, the temperature regulating layer 21 in the photocatalytic reactor is generally cylindrical in shape. This cylindrical structure is disposed inside the shell 20. The sidewall of the temperature regulating layer 21 is tightly connected to the inner wall of the shell 20, and the internal cavity of the temperature regulating layer 21 forms a reaction chamber. A gap is left between the top surface of the temperature regulating layer 21 and the top of the shell 20 to form a feed chamber 25, and a gap is left between the bottom surface of the temperature regulating layer 21 and the bottom of the shell 20 to form a discharge chamber 26.

[0037] In one embodiment, in order to further increase the residence time of the reactants in the reaction chamber, on the one hand, a plurality of through holes 27 are uniformly provided on the top and bottom surfaces of the reaction chamber, and the diameter of the through holes 27 is 5-10 mm, preferably 7-8 mm; on the other hand, the through holes 27 on the top surface of the reaction chamber and the through holes 27 on the bottom surface of the reaction chamber are staggered.

[0038] The through-hole 27 on the top surface of the reaction chamber is formed in the upper temperature regulating layer 21, and the through-hole 27 on the bottom surface of the reaction chamber is formed in the lower temperature regulating layer 21.

[0039] In one embodiment, the temperature regulating device used in the temperature regulating layer 21 is a conventional choice in the art, and this application does not make any requirements. For example, the temperature regulating device used in the temperature regulating layer 21 is an electric heater.

[0040] In one embodiment, the ratio of the height of the reaction chamber to the height of the shell 20 is (0.5-0.7):1, preferably (0.55-0.65):1.

[0041] In one embodiment, a diffuse reflection layer 22 is provided inside the internal cavity of the reaction chamber, and the diffuse reflection layer 22 is placed on the inner wall of the temperature regulating layer 21; the overall structure of the diffuse reflection layer 22 can be conventionally selected in the art, for example, the overall structure of the diffuse reflection layer 22 can be a square cylindrical structure, a circular cylindrical structure or an irregular cylindrical structure, preferably a circular cylindrical structure, and more preferably a circular cylindrical structure without a top surface and a bottom surface.

[0042] The diffuse reflection layer 22 and the inner wall of the temperature regulating layer 21 can be tightly bonded or have a certain gap. Preferably, the diffuse reflection layer 22 and the inner wall of the temperature regulating layer 21 are tightly bonded.

[0043] In one embodiment, the diffuse reflection layer 22 is a reflective grating layer, wherein the reflective grating layer contains 1000-1500 optical slits per millimeter of scribe line. The material of the reflective grating layer includes one or more environmentally friendly materials such as PET, PP, PVC, and TPU.

[0044] In one embodiment, the form of the tunable wavelength light source 24 is conventionally chosen in the art, and this application does not make any special requirements. For example, the light source used in this disclosure is in the form of a rod-shaped light source. The tunable wavelength light source 24 is disposed inside the reaction chamber along the axial direction of the housing 20. Preferably, the tunable wavelength light source 24 is coaxially disposed with the housing 20.

[0045] In one embodiment, the tunable wavelength light source 24 can be selected from the TLS series tunable wavelength light source or the CP-L series wavelength-tunable monochromatic light source; preferably, the tunable wavelength light source 24 includes one or more of xenon lamp sources, QTH tunable quartz halogen lamp sources, deuterium lamp sources, and halogen tungsten lamp sources. In this embodiment, the wavelength of the tunable wavelength light source 24 is 200nm-2500nm.

[0046] In one embodiment, the temperature regulating layer 21 and the tunable wavelength light source 24 are respectively provided with an electrical transmission device, so that the tunable wavelength light source 24 can adjust the light irradiance intensity according to the input power.

[0047] In one embodiment, the catalyst arc-shaped thin plate assembly includes a plurality of catalyst arc-shaped thin plates 23, which are uniformly disposed in the region between the inner side of the diffuse reflection layer 22 and the outer side of the tunable wavelength light source 24.

[0048] The catalyst arc-shaped thin plate 23 is arranged parallel to the tunable wavelength light source 24, that is, the surface of the catalyst arc-shaped thin plate 23 is arranged along the axial direction of the housing 20.

[0049] The catalyst arc-shaped thin plates 23 are arranged in parallel, and the catalyst arc-shaped thin plates 23 are arranged at intervals along the same circumference on a plane perpendicular to the axial direction. In addition, the catalyst arc-shaped thin plates 23 penetrate the reaction chamber.

[0050] In one implementation, such as Figure 3 As shown, the catalyst arc-shaped thin plate 23 is an arc-shaped thin plate of uniform thickness and equal width at both ends; the ratio of the height of the arc-shaped thin plate to the height of the shell 20 is (0.7-0.95):1, preferably (0.75-0.9):1; the thickness of the uniformly thick arc-shaped thin plate is 1-10 mm, preferably 5-10 mm, and more preferably 7-8 mm. The arc α of the arc-shaped thin plate is 20-30 rad, preferably 22-28 rad.

[0051] In one embodiment, the material of the arc-shaped thin plate can be selected from one or more of acrylic sheet, MDF, plywood and fine-mesh board. In order to further improve the light utilization rate, the material of the catalyst arc-shaped thin plate 23 can be set to a transparent arc-shaped thin plate. For example, the material of the arc-shaped thin plate can be a transparent acrylic sheet.

[0052] In one embodiment, the input power of the tunable wavelength light source 24 and / or the temperature regulation layer 21 in each photocatalytic reactor is the same. Specifically, the system further includes a control unit 9 and a carbon dioxide concentration detector at the inlet of the photocatalytic reactor group 2. The control unit 9 is electrically connected to the carbon dioxide concentration detector, the tunable wavelength light source 24 in each photocatalytic reactor, and the temperature regulation layer 21 in each photocatalytic reactor, respectively, for receiving signals from the carbon dioxide concentration detector and adjusting the input power of the tunable wavelength light source 24 and / or the temperature regulation layer 21 in each photocatalytic reactor according to the signals.

[0053] In this embodiment, before the hydrogenation reaction, the photocatalytic reaction temperature is 50–100°C and the light irradiation intensity is 20–200 W / m². 2In the input control unit 9, after the reaction temperature and light irradiation intensity in each photocatalytic reactor reach the input value, the control unit 9 receives the carbon dioxide concentration of the hydrogenation reaction material detected by the carbon dioxide concentration detector installed at the inlet of the photocatalytic reactor group 2. When the carbon dioxide concentration in the hydrogenation reaction material is less than a first threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are increased; the first threshold is 28-33% by volume. When the carbon dioxide concentration in the hydrogenation reaction material is greater than a second threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are decreased; the second threshold is 20-25% by volume.

[0054] The second aspect of this disclosure is a method for performing a carbon dioxide catalytic reduction hydrogenation reaction using the system described in the first aspect. The method includes: mixing carbon dioxide and hydrogen in a gas mixer 1 to obtain hydrogenation reaction materials; allowing the hydrogenation reaction materials to enter each photocatalytic reactor and contact the photocatalyst attached to the catalyst arc-shaped thin plate assembly to perform a hydrogenation reaction, thereby obtaining hydrogenation reaction products; and allowing the hydrogenation reaction products in each photocatalytic reactor to sequentially enter a gas collector 5 via a fan 3 and a liquid collector 4.

[0055] In this embodiment, the hydrogenation reactants are subjected to hydrogenation reaction through a group of photocatalytic reactors 2, which consists of multiple photocatalytic reactors connected in parallel. The resulting hydrogenation reaction products are then separated by a liquid collector 4, allowing the liquid phase product to exit the system and the separated gas phase to be collected. This method can improve the throughput per unit time of the hydrogenation reaction while ensuring the effectiveness of the hydrogenation reaction.

[0056] In one embodiment, the input power of the tunable wavelength light source 24 and / or the temperature regulation layer 21 in each photocatalytic reactor is the same. Specifically, the conditions for the hydrogenation reaction include: a reaction temperature of 50–100°C, preferably 60–80°C; a reactant residence time of 5–10 s, preferably 7–8 s; and a light irradiance of 20–200 W / m² for the tunable wavelength light source 24. 2 Preferably, it is 50-150W / m 2 .

[0057] In this embodiment, the hydrogenation reaction rate increases with increasing reaction temperature because the activation energy decreases, molecular motion speed increases, and the collision frequency between reactant molecules increases. However, the reaction rate slows down when the temperature exceeds a critical point because the photocatalyst deactivates at high temperatures. Therefore, the heating layer is improved to be temperature-adjustable, and the optimal reaction temperature must be selected according to different catalysts to maximize reaction efficiency. Only light absorbed by the reaction system can trigger the photochemical reaction, and the system exhibits selective light absorption with a suitable wavelength.

[0058] In one embodiment, the hydrogen can be produced by electrolysis of water driven by renewable energy sources such as solar, wind, and biomass power generation, wherein the concentration of the hydrogen is 90% by volume or higher. The carbon dioxide can be sourced from one or more of the following: burning fossil fuels, industrial production, agricultural activities, and energy consumption, wherein the concentration of the carbon dioxide is 90% by volume or higher.

[0059] In this embodiment, since the hydrogen raw material is generated by water electrolysis, and the electricity generated by the aforementioned renewable energy source is unstable, there will be fluctuations in the hydrogen concentration. Therefore, the ratio of carbon dioxide to hydrogen in the hydrogenation reaction material obtained by mixing in gas mixer 1 is unstable. By using the method disclosed herein, the reaction conditions of the hydrogenation reaction can be flexibly adjusted according to the above ratio, and the problem of product quality deterioration caused by fluctuations in the quality of raw materials can be avoided.

[0060] In one embodiment, the molar ratio of hydrogen and carbon dioxide feed into the gas mixer 1 is (2-4):1, preferably (2.5-3.5):1.

[0061] In one embodiment, the photocatalyst comprises one or more of titanium dioxide particles, zinc oxide particles, and tin oxide particles, preferably titanium dioxide particles. Preferably, the average particle size of the photocatalyst is 10–50 nm, more preferably 20–40 nm.

[0062] In this embodiment, when light with energy greater than or equal to the band gap irradiates the photocatalyst nanoparticles, electrons in their valence band will be excited and jump to the conduction band, leaving relatively stable holes in the valence band, thereby forming electron-hole pairs, which cause the carbon dioxide reduction reaction to occur. Therefore, the hydrogenation reaction of carbon dioxide and hydrogen needs to be carried out in the presence of a photocatalyst.

[0063] In one embodiment, the method further includes: allowing the hydrogenation reaction product to enter the liquid collector 4 under the action of the blower 3 for gas-liquid separation; allowing the obtained liquid phase product to enter the fractionation device for separation processing to obtain hydrocarbons with high purity, which can be used directly as fuel or made into chemical reagents; allowing the liquid phase product to exit the system; and allowing the separated gas phase to enter the gas collector 5.

[0064] In one embodiment, the gaseous material collected by the gas collector 5 is fed into a hydrogen purification device for hydrogen purification treatment and then returned to the gas mixer for continued use.

[0065] In one embodiment, the liquid phase product obtained in liquid collector 4 mainly consists of hydrocarbons and water. The separated gas phase obtained in gas collector 5 mainly consists of hydrocarbons, hydrogen, and carbon dioxide. The hydrocarbons primarily include one or more of methane, ethylene, ethane, and propylene.

[0066] In one implementation, such as Figure 1 , Figure 2 and Figure 4 As shown, the methods for carrying out the catalytic reduction hydrogenation reaction of carbon dioxide include:

[0067] Carbon dioxide and hydrogen are mixed in gas mixer 1 to obtain hydrogenation reaction material; wherein the molar ratio of carbon dioxide to hydrogen is (2-4):1.

[0068] The photocatalytic reaction temperature is 50–100℃, and the light irradiance is 20–200 W / m². 2 In the input control unit 9, after the reaction temperature and light irradiation intensity in each photocatalytic reactor reach the input value, the control unit 9 receives the carbon dioxide concentration of the hydrogenation reaction material detected by the carbon dioxide concentration detector installed at the inlet of the photocatalytic reactor group 2. When the carbon dioxide concentration in the hydrogenation reaction material is less than a first threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are increased; the first threshold is 28-33 vol%. When the carbon dioxide concentration in the hydrogenation reaction material is greater than a second threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are decreased; the second threshold is 20-25 vol%. The residence time of the hydrogenation reaction material is 5-10 s.

[0069] The hydrogenation reactants are introduced into the photocatalytic reactor group 2 and come into contact with the photocatalyst attached to the catalyst arc-shaped thin plate group inside each photocatalytic reactor to carry out the hydrogenation reaction and obtain the hydrogenation reaction product.

[0070] The hydrogenation reaction product is introduced into a liquid collector 4 by the blower 3 for gas-liquid separation. The resulting liquid product is then introduced into a fractionation unit for further separation, yielding high-purity hydrocarbons that can be used directly as fuel or manufactured into chemical reagents. The liquid product exits the system, and the separated gas phase enters a gas collector 5. The gas phase material collected by the gas collector 5 is then introduced into a hydrogen purification unit for hydrogen purification before being returned to the gas mixer for continued use.

[0071] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited thereto. The hydrogen used in this disclosure is produced by electrolyzing water using electricity generated by a wind turbine, and has a purity of 98% by volume; the carbon dioxide used in this disclosure is obtained by burning fossil fuels, and has a purity of 98% by volume.

[0072] Example 1

[0073] use Figure 4 The system performs a carbon dioxide catalytic reduction and hydrogenation reaction, wherein the photocatalytic reactor used is such as... Figure 1 and Figure 2 As shown, the photocatalytic reactor group contains six photocatalytic reactors. The shell of each reactor is cylindrical, with a height of 1.2m and a cross-sectional diameter of 1m. The reaction chamber has a height of 0.8m and a cross-sectional diameter of 0.8m. The through-hole 27 has a diameter of 5mm. The catalyst arc-shaped thin plate used in the photocatalytic reactor is shown in the figure. Figure 3 As shown, the arc α of the catalyst coating arc plate is 25 rad, the thickness is 1 mm, the height of the arc plate is 0.9 m, and the photocatalyst attached to the inner wall is titanium dioxide particles with a particle size of 30 nm.

[0074] Methods for the catalytic reduction hydrogenation of carbon dioxide include:

[0075] Carbon dioxide and hydrogen are mixed in gas mixer 1 to obtain hydrogenation reaction material; wherein the molar ratio of hydrogen to carbon dioxide is 3:1.

[0076] The photocatalytic reaction temperature was 70℃ and the light irradiance was 50W / m². 2 In the input control unit 9, after the reaction temperature and light irradiation intensity in each photocatalytic reactor reach the input value, the control unit 9 receives the carbon dioxide concentration of the hydrogenation reaction material detected by the carbon dioxide concentration detector installed at the inlet of the photocatalytic reactor group 2. When the carbon dioxide concentration in the hydrogenation reaction material is less than a first threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are increased; the first threshold is 30% by volume. When the carbon dioxide concentration in the hydrogenation reaction material is greater than a second threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are decreased; the second threshold is 22% by volume. The residence time of the hydrogenation reaction material is 7 seconds.

[0077] The hydrogenation reactants are introduced into the photocatalytic reactor group 2 and come into contact with the photocatalyst attached to the catalyst arc-shaped thin plate group inside each photocatalytic reactor to carry out the hydrogenation reaction and obtain the hydrogenation reaction product.

[0078] The hydrogenation reaction product is introduced into a liquid collector 4 by the blower 3 for gas-liquid separation. The resulting liquid product is then introduced into a fractionation unit for further separation, yielding high-purity hydrocarbons that can be used directly as fuel or manufactured into chemical reagents. The liquid product exits the system, and the separated gas phase enters a gas collector 5. The gas phase material collected by the gas collector 5 is then introduced into a hydrogen purification unit for hydrogen purification before being returned to the gas mixer for continued use.

[0079] Example 2

[0080] use Figure 4 The system performs a carbon dioxide catalytic reduction hydrogenation reaction, and the method for performing the carbon dioxide catalytic reduction hydrogenation reaction is the same as in Example 1, except that no carbon dioxide concentration detector is set at the inlet of the photocatalytic reactor group of the system and no control unit is included, so that the reaction conditions of the photocatalytic reactor do not change with the concentration of carbon dioxide in the hydrogenation reaction material.

[0081] Comparative Example 1

[0082] use Figure 4 The system performs the catalytic reduction and hydrogenation reaction of carbon dioxide, the difference being that it uses... Figure 5 The photocatalytic reactor in this embodiment replaces the photocatalytic reactor in Example 1 for hydrogenation. This reactor has a cylindrical structure and, from the outside in, includes a heating layer 29, a reflective layer 30, a reaction tube 31, and a light source 32. The heating layer 29 is a hollow cylinder used to provide and maintain the required temperature for the entire reactor interior. The reflective layer 30 is attached to the inner wall of the heating layer 29 and is used to perform multiple reflections of the light emitted by the light source 32. The light source 32 is rod-shaped and extends coaxially with the heating layer 29 to provide illumination for the photocatalytic reaction. The reaction tube 31 is a hollow tube and extends spirally around the light source 32 through the entire heating layer. Furthermore, the reaction tube 31 has a material inlet and a material outlet at both ends, and its inner wall is coated with a photocatalyst, thereby maintaining a spiral transport and synchronous reaction within the hollow tube.

[0083] Table 1. Properties of the products in the examples and comparative examples.

[0084]

[0085] As shown in Table 1, a comparison of the data from Examples 1-2 and Comparative Example 1 reveals that the method of this disclosure can increase the throughput per unit time of the hydrogenation reaction while ensuring the effectiveness of the hydrogenation reaction. Specifically, a comparison of the data from Examples 1 and 2 shows that by flexibly adjusting the hydrogenation reaction conditions of the photocatalytic reactor based on the carbon dioxide concentration of the hydrogenation reactants at the inlet of the photocatalytic reactor group, the hydrogenation reaction effect of carbon dioxide can be further improved; a comparison of the data from Examples 1 and Comparative Example 1 shows that the photocatalytic reactor of this disclosure can further improve the hydrogenation reaction effect of carbon dioxide.

[0086] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0087] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0088] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A system for a multi-stage parallel catalytic reduction and hydrogenation reaction of carbon dioxide, characterized in that, The system includes a gas mixer (1), a photocatalytic reactor group (2), a fan (3), a liquid collector (4), and a gas collector (5); The photocatalytic reactor group (2) includes multiple photocatalytic reactors arranged in parallel; The photocatalytic reactor includes a cylindrical shell (20), a temperature regulating layer (21), a diffuse reflection layer (22), a catalyst arc-shaped thin plate assembly, and a tunable wavelength light source (24); the shell (20) is provided with a feed chamber (25), a reaction chamber, and a discharge chamber (26) from top to bottom; the temperature regulating layer (21) covers the outside of the reaction chamber; the catalyst arc-shaped thin plate assembly and the tunable wavelength light source (24) are arranged from the outside to the inside of the reaction chamber. The feeding chamber (25) and the discharging chamber (26) are respectively provided with a feeding port and a discharging port; the feeding port is connected to the outlet of the gas mixer (1), and the discharging port is connected to the inlet of the blower (3); the top and bottom surfaces of the reaction chamber are respectively provided with through holes (27) so that the feeding chamber (25) and the discharging chamber (26) are connected to the reaction chamber through the through holes (27); The catalyst arc-shaped thin plate assembly includes multiple catalyst arc-shaped thin plates (23), and the sidewalls of the catalyst arc-shaped thin plates (23) are attached with photocatalysts; the upper and lower ends of the catalyst arc-shaped thin plates (23) extend to the feed chamber (25) and the discharge chamber (26) respectively, and the concave surface of the arc-shaped thin plates faces the axis of the shell (20); The diffuse reflection layer (22) is disposed on the inner wall of the temperature regulating layer (21); The adjustable wavelength light source (24) is arranged along the axial direction of the housing (20) inside the reaction chamber and is coaxial with the reaction chamber; The adjustable wavelength light source (24) includes one or more of the following: xenon lamp light source, deuterium lamp light source, and halogen tungsten lamp light source; The surface of the catalyst arc-shaped thin plate (23) extends along the axial direction of the shell (20). The catalyst arc-shaped thin plate (23) is an arc-shaped thin plate of equal thickness and equal width at the top and bottom. The thickness of the arc-shaped thin plate is 1~10mm. Multiple catalyst arc-shaped thin plates (23) are arranged in parallel, and the multiple catalyst arc-shaped thin plates (23) are arranged at intervals along the same circumference on a plane perpendicular to the axial direction; The height ratio of the reaction chamber to the shell (20) is (0.5~0.7):1; The diameter of the through hole (27) is 5~10mm; The system also includes a control unit (9) and a carbon dioxide concentration detector located at the inlet of the photocatalytic reactor group (2); The control unit (9) is electrically connected to the carbon dioxide concentration detector, the tunable wavelength light source (24) in each of the photocatalytic reactors and the temperature regulation layer (21) in each of the photocatalytic reactors, respectively, for receiving the signal from the carbon dioxide concentration detector and adjusting the input power of the tunable wavelength light source (24) and / or the temperature regulation layer (21) in each of the photocatalytic reactors according to the signal.

2. The system according to claim 1, characterized in that, The number of photocatalytic reactors in the photocatalytic reactor group (2) is more than 3.

3. A method for performing a carbon dioxide catalytic reduction hydrogenation reaction using the system described in claim 1 or 2, characterized in that, The method includes: After carbon dioxide and hydrogen are mixed in a gas mixer (1), hydrogenation reaction material is obtained; The hydrogenation reactants are introduced into each photocatalytic reactor and come into contact with the photocatalyst attached to the arc-shaped thin plate assembly to carry out the hydrogenation reaction, thereby obtaining the hydrogenation reaction products. The hydrogenation reaction products in each of the photocatalytic reactors are sequentially passed through a blower (3) and a liquid collector (4) into a gas collector (5).

4. The method according to claim 3, characterized in that, The photocatalyst includes one or more of titanium dioxide particles, zinc oxide particles, and tin oxide particles.

5. The method according to claim 3, characterized in that, The conditions for the hydrogenation reaction include: a reaction temperature of 50~100℃, a reactant residence time of 5~10s, and a light irradiance of 20~200W / m² from the tunable wavelength light source (24). 2 .

6. The method according to claim 3, characterized in that, The method further includes a control unit (9) adjusting the input power of the tunable wavelength light source (24) and / or the temperature regulation layer (21) in each photocatalytic reactor according to the concentration of carbon dioxide in the hydrogenation reactant and the number of photocatalytic reactors in the photocatalytic reactor group (2).

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