Multi-stage phoenix tree branch flow-equalizing gas-solid photocatalytic reactor and reaction method thereof

Abstract

The invention belongs to the technical field of photocatalysis, and discloses a multistage phoenix tree branch flow-equalizing gas-solid photocatalytic reactor and a reaction method thereof. Wherein the multistage phoenix tree branch flow-equalizing gas-solid photocatalytic reactor comprises a bottom plate, a splitter plate is mounted at the top of the bottom plate, an upper cover plate is mounted at the top of the splitter plate, a through hole is formed in the splitter plate, the through hole is matched with a catalyst loading surface, phoenix tree branch flow-equalizing distribution runners are arranged on two sides of the through hole, and the phoenix tree branch flow-equalizing distribution runners are communicated with the upper cover plate. The phoenix tree branch flow-equalizing distribution flow channel comprises a main flow channel located at the bottom of the air inlet and the air outlet, a plurality of stages of branch flow channels are connected between the main flow channel and the through hole, the branch flow channels comprise mother flow channels, and the mother flow channels are connected with son flow channels through forks; according to the invention, on the basis of the fluid distribution and flow-equalizing design of the phoenix tree branch flow-equalizing distribution runner, the entering gas can be uniformly contacted with the surface of the photocatalyst, so that the photocatalytic reaction efficiency is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalysis, and particularly relates to a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor and a reaction method thereof. Background Art

[0002] As a cutting-edge environmental protection technology, the core of photocatalysis technology is to utilize light energy to stimulate chemical reactions on the surface of the catalyst, showing great application potential in pollutant decomposition and resource utilization. Among them, photocatalytic CO2 reduction technology has received extensive attention in recent years. It can convert CO2 into methanol, carbon monoxide or other hydrocarbons through photocatalysts, providing a technical path for carbon neutrality.

[0003] However, in the actual application of current photocatalysis technology, especially in the field of treating gaseous pollutants and photocatalytic CO2 reduction, photocatalytic reactors usually adopt single-channel or parallel flow channel designs, making it difficult to effectively regulate and control the flow rate distribution of reactant gases on the surface of the catalyst. Different reactant gas flow rates have a significant impact on the photocatalytic process. Uneven gas flow rates will lead to insufficient contact of reactants in some areas on the surface of the catalyst, resulting in waste of catalyst active sites, and thus reducing the reaction efficiency and product selectivity.

[0004] Therefore, photocatalysis technology still faces the key technical problem that due to the inability to control the flow rate of reactant gases on the surface of the catalyst, the gas cannot be evenly distributed, resulting in too high gas concentration on some parts of the catalyst surface, while on the other parts, the reaction cannot proceed fully due to insufficient gas, thus affecting the overall catalytic efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor and a reaction method thereof to overcome the problems existing in the prior art. Based on the fluid distribution and uniform flow design of the sycamore branch uniform flow distribution channel, the present invention can evenly distribute gas to the surface of the catalyst through multi-stage branch channels (sycamore branch uniform flow distribution channels), ensuring a uniform flow rate distribution of gas in the reactor. The sycamore branch uniform flow distribution channel enables the incoming gas to evenly contact the surface of the photocatalyst, thereby significantly improving the catalytic reaction efficiency; by ensuring the high light transmittance of quartz glass, the light energy can be transmitted to the surface of the photocatalyst without loss, ensuring the uniform distribution and efficient utilization of light energy, and further enabling efficient photocatalytic reactions; through the two-way airbag, cyclic reactions can be achieved, significantly reducing the overall energy consumption and operating costs of the system compared with traditional parallel flow or single-channel reactors, and further improving the utilization rate of reaction gases; through the sealing groove and the sealing rubber ring, a closed structure is formed, further enhancing the airtightness of the structure.

[0006] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0007] In a first aspect, the present invention provides a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor, which includes a bottom plate. A flow distribution plate is installed on the top of the bottom plate, and an upper cover plate is installed on the top of the flow distribution plate.

[0008] A catalyst loading surface is installed on the top of the bottom plate for placing a photocatalyst during experiments.

[0009] Through holes are formed in the flow distribution plate, and the through holes are adapted to the catalyst loading surface for the catalyst loading surface to pass through the through holes. Uniform flow distribution channels of sycamore branches are arranged on both sides of the through holes. During use, the catalyst loading surface passes through the through holes, and the reaction gas uniformly flows through the catalyst loading surface from one side of the uniform flow distribution channels of sycamore branches to carry out a photocatalytic reduction reaction with the photocatalyst, and the obtained reaction products uniformly flow out from the uniform flow distribution channels of sycamore branches on the other side. The uniform flow distribution channels of sycamore branches include main flow channels located at the bottoms of the air inlet and the air outlet. A number of stages of branch flow channels are connected between the main flow channels and the through holes. The branch flow channels include mother flow channels, and the mother flow channels are connected with sub-flow channels through bifurcations. The number of branch flow channels increases stage by stage, the diameter of the branch flow channels decreases stage by stage, and the flow velocity of the branch flow channels decreases stage by stage. The relationship between the hydraulic diameter and the length of the uniform flow distribution channels of sycamore branches satisfies:

[0010]

[0011] In the formula, D represents the hydraulic diameter in mm; L represents the flow channel length in mm; n represents the number of sub-flow channels at the bifurcation of each branch flow channel; i represents the flow channel stage number of the mother flow channel at the bifurcation of each branch flow channel.

[0012] Furthermore, sealing grooves are respectively arranged on the top of the bottom plate and the bottom of the upper cover plate, and sealing rubber rings are installed in the sealing grooves.

[0013] Furthermore, n = 2.

[0014] Furthermore, a quartz glass is installed on the upper cover plate. The quartz glass is located on the top of the through hole for transmitting a light source to the catalyst loading surface. An air inlet is formed at one end of the upper cover plate, and an air outlet is formed at the other end. The air inlet is sequentially connected with a water supply bottle, a washing bottle, an air inlet flow monitoring device and a circulation pump through pipelines. The air outlet is sequentially connected with a collection bottle and an air outlet flow monitoring device through pipelines. A two-way air bag is also connected between the circulation pump and the air outlet flow monitoring device through a pipeline.

[0015] Furthermore, a light source transmission window is formed on the upper cover plate, and the quartz glass is installed on the upper cover plate through the light source transmission window.

[0016] Furthermore, a two-way air valve is installed on the two-way air bag.

[0017] Further, the photocatalyst is titanium dioxide or metal-doped titanium dioxide.

[0018] In a second aspect, the present invention provides a multi-stage plane tree branch uniform flow gas-solid photocatalytic reaction method. Based on the above-mentioned multi-stage plane tree branch uniform flow gas-solid photocatalytic reactor, the method includes the following steps:

[0019] Step 1: Place the photocatalyst on the catalyst loading surface, introduce CO2 gas into the air inlet, and at the same time transmit the light source to the catalyst loading surface through quartz glass;

[0020] Step 2: The CO2 gas is uniformly introduced onto the catalyst loading surface through the plane tree branch uniform flow distribution channel and undergoes a photocatalytic reduction reaction with the photocatalyst to obtain gaseous products or gaseous and liquid products. Among them, unreacted CO2 gas exists in the gaseous products;

[0021] Step 3: The gaseous and liquid products are introduced into the air outlet. The gaseous products are introduced into the two-way gas bag. The unreacted CO2 gas in the gaseous products enters the air inlet again through the two-way gas bag, and step 2 is executed;

[0022] Further, the air inlet is sequentially connected with a water supply bottle, a washing bottle, an air inlet flow monitoring device, and a circulation pump through pipelines; the air outlet is sequentially connected with a collection bottle and an air outlet flow monitoring device through pipelines. A two-way gas bag is also connected between the circulation pump and the air outlet flow monitoring device through a pipeline;

[0023] Further, the introduction of CO2 gas into the air inlet in step 1 is specifically as follows: CO2 gas is introduced. The CO2 gas sequentially passes through the circulation pump, the air inlet flow monitoring device, the washing bottle, and the water supply bottle and enters the air inlet; step 3 is specifically as follows: the gaseous and liquid products are introduced into the air outlet. The liquid products enter the collection bottle. The gaseous products flow through the air outlet flow monitoring device and are introduced into the two-way gas bag. The unreacted CO2 gas in the gaseous products enters the air inlet again through the two-way gas bag, and step 2 is executed;

[0024] Further, the flow rate of the CO2 gas is 0.5 - 2 m / s.

[0025] The above technical solutions have the following advantages or beneficial effects:

[0026] In a first aspect, the present invention provides a multi-stage parasol branch uniform flow gas-solid photocatalytic reactor. Through the gas distribution design of the parasol branch uniform flow distribution channel, this channel can evenly distribute the fluid from the main inlet to the target area to achieve precise control of the flow rate and efficient coverage. The flow rate and velocity of each stage of the branch are optimized by fluid mechanics design. By setting a multi-stage branch channel from the main flow channel to the through hole, the main flow channel is the main channel for the fluid to enter, responsible for introducing gas or liquid from the air inlet into the channel network. The number of branch channels increases gradually, the diameter of the branch channels decreases gradually, and the flow velocity of the branch channels decreases gradually, significantly improving the gas flow path and distribution state to ensure uniform gas or liquid flow velocity on the catalyst surface, and ensuring that the reaction gas or liquid uniformly covers and maximizes the contact area on the photocatalyst surface, thereby greatly improving the reaction efficiency on the catalyst surface, significantly enhancing the efficiency of the photocatalytic reaction, increasing the utilization rate of active sites by more than 30%, and avoiding problems such as uneven gas flow, stagnation in local channels, and dead zones on the photocatalyst surface, resulting in low utilization rate of the photocatalyst and low photocatalytic efficiency; by precisely controlling the flow rate of the reaction fluid on the catalyst surface, the product selectivity in the photocatalytic product can be improved. Due to the uniform surface flow rate, the contact of the reactants is more balanced, and it is not easy to produce by-products, so that a high-concentration target product can be generated; through the uniform flow rate distribution, the non-uniformity of the reaction rate can also be reduced, and the accuracy of the reaction kinetic model can be improved, thereby providing theoretical support for the optimization of the catalytic process and industrial applications.

[0027] Furthermore, through the cooperation of the sealing groove and the sealing rubber ring, it has the advantages of high temperature resistance and corrosion resistance, can further improve the airtightness of the device, and the sealing structure significantly enhances the stability of the device, and can adapt to the complex high-pressure and corrosive gas environment in the industrial scenario.

[0028] Furthermore, by setting the case of n = 2, there are fewer sub-channels at the bifurcation of each branch channel, which helps to maintain better flow uniformity, avoid the generation of dead zones, and ensure that the gas can be evenly distributed on the catalyst surface.

[0029] Furthermore, through the high light transmittance of the quartz glass, it ensures that the light energy is transmitted to the surface of the photocatalyst without loss, ensuring the uniform distribution and efficient utilization of the light energy, and can further achieve an efficient photocatalytic reaction; through the two-way air bag, a cyclic reaction can be realized, greatly reducing the overall energy consumption and operating cost of the system, and further improving the utilization rate of the reaction gas; the present invention is also applicable to various application scenarios such as the decomposition of high-efficiency volatile organic compounds (VOCs), industrial waste gas purification, air quality improvement, and photocatalytic CO2 reduction reaction, and can achieve pollutant purification and resource utilization.

[0030] Furthermore, through the two-way air valve, the controllability of the gas flow direction can be ensured, and the unreacted CO2 gas can be recycled again, further improving the utilization rate of the reaction gas.

[0031] Furthermore, the photocatalyst is titanium dioxide or metal-doped titanium dioxide, which can catalytically decompose volatile organic compounds and reduce CO2 to methanol, carbon monoxide or other hydrocarbons.

[0032] In the second aspect, the present invention provides a multi-stage sycamore branch uniform flow gas-solid photocatalytic reaction method. By placing the photocatalyst on the catalyst loading surface and using quartz glass to transmit light to the catalyst, it ensures that the photocatalyst can fully receive light energy, thereby improving the efficiency of the photocatalytic reduction reaction; through the sycamore branch uniform flow distribution channel, the CO2 gas can be evenly distributed on the catalyst loading surface, further promoting the efficient progress of the reaction; the unreacted CO2 gas is recycled by being re-introduced into the inlet through the two-way air bag, which not only reduces resource waste but also improves the conversion rate of CO2, making the whole reaction process more environmentally friendly and economical; the gaseous products and liquid products are collected separately, improving the controllability and operability of the whole reaction process.

[0033] Furthermore, the washing bottle can preliminarily remove impurities from the input CO2 gas to remove acidic gases, solid particles and other impurity gases in the raw material gas. The water supply bottle can humidify the input CO2 gas, that is, by introducing water vapor into the CO2 gas, the humidity of the gas is increased, providing necessary water molecules for the photocatalytic reduction reaction. The humidified CO2 gas enters the photocatalytic reactor through the inlet, which helps to improve the photocatalytic reaction efficiency; the circulation pump (W) can provide gas circulation power to ensure the flow of the reaction gas in the system; the collection bottle is used to collect liquid products. After the liquid products are dissolved in water, they can be purified and recovered through subsequent separation devices, improving the recovery rate of the products and reducing environmental pollution; both the inlet flow monitoring device (FI) and the outlet flow monitoring device (FI) are mass flow meters, which can monitor the input and output flows of the reaction gas in real time to ensure that the flow rate of the reaction gas operates within the optimal range (0.5 - 2 m / s), thereby ensuring the efficiency and stability of the catalytic reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor of the present invention;

[0035] Figure 2 is a top view of the upper cover plate of a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor of the present invention;

[0036] Figure 3Top view of the flow distributor plate of a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to the present invention;

[0037] Figure 4 Top view of the bottom plate of a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to the present invention;

[0038] Figure 5 Schematic structural diagram of the sycamore branch uniform flow distribution channel of a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to the present invention;

[0039] Figure 6 Flow field simulation diagram of the uniform flow effect of a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to the present invention;

[0040] Figure 7 Flow chart of a multi-stage sycamore branch uniform flow gas-solid photocatalytic reaction method according to the present invention;

[0041] In the figure, 1 - quartz glass; 2 - upper cover plate; 21 - light source transmission window; 3 - flow distributor plate; 31 - sycamore branch uniform flow distribution channel; 32 - through hole; 4 - bottom plate; 5 - air inlet; 6 - air outlet; 7 - sealing groove; 8 - catalyst loading surface. Detailed implementation manners

[0042] The following further elaborates on the present invention in detail with specific embodiments, which are explanations of the present invention rather than limitations.

[0043] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily need to be limited to those clearly listed steps or units, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0045] Example 1:

[0046] Referring to Figure 1 , the present invention provides a multi-stage parasol branch uniform flow gas-solid photocatalytic reactor, which includes an upper cover plate 2, a flow dividing plate 3, and a bottom plate 4. The flow dividing plate 3 is installed on the top of the bottom plate 4, and the upper cover plate 2 is installed on the top of the flow dividing plate 3; Referring to Figure 4 , a catalyst loading surface 8 is installed on the top of the bottom plate 4, and a photocatalyst is provided on the catalyst loading surface 8 for CO2 reduction reaction and decomposition of volatile organic compounds. The photocatalyst is titanium dioxide or titanium dioxide doped with metal, and is used for catalytic decomposition of volatile organic compounds and reduction of CO2 to methanol, carbon monoxide or other hydrocarbons. A sealing groove 7 is provided on the top of the bottom plate 4, and a sealing rubber ring is installed in the sealing groove 7;

[0047] Preferably, a plurality of corresponding bolt holes are provided on the upper cover plate 2, the flow dividing plate 3 and the bottom plate 4. The upper cover plate 2, the flow dividing plate 3 and the bottom plate 4 are installed through the bolt holes and bolts to form a double-sided airtight structure, which can be disassembled independently, facilitating maintenance and cleaning. It can not only be applied to the refined research in the laboratory, but also meet the requirements of the complex industrial-scale waste gas treatment environment, avoiding gas leakage;

[0048] Preferably, the sealing groove 7 can be an oval groove or a square groove, which is consistent with the shape of the sealing rubber ring, further enhancing the airtightness of the structure;

[0049] Preferably, the sealing rubber ring has the advantages of high temperature resistance and corrosion resistance, which can further improve the airtightness of the device.

[0050] Referring to Figure 3 、 Figure 5 and Figure 6, a through hole 32 is formed in the flow splitter plate 3. The through hole 32 is adapted to the catalyst loading surface 8. On both sides of the through hole 32, there are plane tree branch uniform flow distribution channels 31. The plane tree branch uniform flow distribution channels 31 include main flow channels at the bottom of the air inlet 5 and the air outlet 6. The main flow channel is the inlet of the fluid, similar to the main trunk of a plane tree, and is used to transport the fluid to the entire flow splitting system. From the main flow channel to the through hole 32, multi-level branch channels are formed. The multi-level branch channels are further divided into first-level branch channels and second-level branch channels. The first-level branch channels are the primary bifurcations of the main trunk and are used to achieve preliminary fluid distribution to balance the fluid velocity and flow rate. The second-level branch channels are finer bifurcated channels and are used to evenly distribute the fluid to the catalyst surface. The diameter of the main flow channel is larger to ensure sufficient fluid flow rate and stable fluid velocity, providing uniform pressure support for the distribution of subsequent branch channels. The length and cross-sectional size of the main flow channel are designed and optimized according to the properties and flow rate requirements of the fluid to reduce the fluid pressure drop; the branch channels, that is, the first-level branch channels and the second-level branch channels, include mother channels. The mother channels are connected with sub-channels at the bifurcation. The number of branch channels increases step by step, the diameter of the branch channels decreases step by step, and the flow velocity of the branch channels decreases step by step. The relationship between the hydraulic diameter and the length of the plane tree branch uniform flow distribution channels 31 satisfies:

[0051]

[0052] In the formula, D represents the hydraulic diameter, with the unit of mm; L represents the flow channel length, with the unit of mm; n represents the number of sub-channels at the bifurcation of each branch channel; i represents the flow channel level of the mother channel at the bifurcation of each branch channel; it significantly improves the gas flow path and distribution state, enables the input reaction gas to be evenly distributed through the multi-level branch channels, evenly contacts the surface of the photocatalyst, and ensures that the reaction gas is evenly covered on the photocatalyst surface and maximizes the contact area, thereby significantly enhancing the efficiency of the photocatalytic reaction, avoiding problems such as uneven gas flow, stagnation in local flow channels, and dead zones on the photocatalyst surface, which lead to low utilization rate of the photocatalyst and low photocatalytic efficiency. During use, the catalyst loading surface 8 passes through the through hole 32, and the reaction gas evenly flows through the catalyst loading surface 8 from the plane tree branch uniform flow distribution channels 31 on one side and undergoes a photocatalytic reduction reaction with the photocatalyst. The obtained reaction products evenly flow out from the plane tree branch uniform flow distribution channels 31 on the other side;

[0053] Preferably, n = 2. There are fewer sub-channels at the bifurcation of each branch channel, which helps to maintain better flow uniformity, avoid the generation of dead zones, and ensure that the gas can be evenly distributed on the catalyst surface. When the number of branches increases to n = 3 or n = 4, the geometric shape of the channel becomes more complex, and the gas flow rate gradually decreases. Especially in the case of low flow rates, problems of uneven flow rates are likely to occur, resulting in gas retention or backflow, forming a backflow area. These backflow areas will affect the uniform distribution of the gas on the catalyst surface and reduce the utilization efficiency of the catalyst. Therefore, the number of sub-channels at the bifurcation of each branch channel is selected to be 2;

[0054] Preferably, the uniformity (v min / v max ) of different channels is shown in the following table:

[0055] Table 1 Comparison table of the uniformity (v min / v max ) of different channels

[0056]

[0057] By comparing the flow uniformity, is the optimal dendritic channel structure.

[0058] Refer to Figure 2 , a quartz glass 1 is installed on the upper cover plate 2, and the quartz glass 1 is located at the top of the through hole 32. Specifically, a light source transmission window 21 is opened on the upper cover plate 2, and the quartz glass 1 is installed on the upper cover plate 2 through the light source transmission window 21. During use, the light source is transmitted to the catalyst loading surface 8 through the quartz glass 1, ensuring the uniform distribution and efficient utilization of light energy. An air inlet 5 is opened at one end of the upper cover plate 2, and an air outlet 6 is opened at the other end. The air inlet 5 and the air outlet 6 are used to connect to external gas pipelines; during use, the air inlet 5 is sequentially connected with a water supply bottle, a washing bottle, an air inlet flow monitoring device, and a circulation pump through pipelines. The circulation pump is used to provide the power for gas circulation to ensure the flow of reaction gas in the system. The washing bottle is used to preliminarily remove impurities from the input CO2 gas to remove acidic gases, solid particles, and other impurity gases in the raw material gas. The water supply bottle is used to moisten the input CO2 gas, that is, by introducing water vapor into the CO2 gas, the humidity of the gas is increased, providing the necessary water molecules for the photocatalytic reduction reaction. The moistened CO2 gas enters the photocatalytic reactor through the air inlet 5, which helps to improve the photocatalytic reaction efficiency. The air outlet 6 is sequentially connected with a collection bottle and an air outlet flow monitoring device through pipelines. A two-way air bag is also connected between the circulation pump and the air outlet flow monitoring device through a pipeline. A two-way air valve is installed on the two-way air bag to ensure the controllability of the gas flow direction and realize the circulation reaction. A sealing groove 7 is provided at the bottom of the upper cover plate 2, and a sealing rubber ring is installed in the sealing groove 7;

[0059] Preferably, the light transmittance of the quartz glass 1 is greater than 90%, facilitating the efficient transmission of ultraviolet or visible light;

[0060] Preferably, both the inlet gas flow monitoring device and the outlet gas flow monitoring device are mass flow meters, used to monitor the input and output flow rates of the reaction gas in real time, so as to ensure that the flow rate of the reaction gas operates within the optimal range (0.5 - 2 m / s), thereby guaranteeing the efficiency and stability of the catalytic reaction;

[0061] Preferably, the sealing groove 7 can be an oval groove or a square groove, which is consistent with the shape of the sealing rubber ring, further enhancing the tightness of the structure;

[0062] Preferably, the sealing rubber ring has the advantages of high temperature resistance and corrosion resistance, and can further improve the tightness of the device.

[0063] Example 2:

[0064] See Figure 7 , the present invention provides a multi-stage Chinese parasol tree branch uniform flow gas-solid photocatalytic reaction method, including the following steps:

[0065] Step 1, place TiO2 (titanium dioxide) on the catalyst loading surface 8, and introduce CO2 (carbon dioxide) gas at a flow rate of 1 m / s. The CO2 gas passes through the circulation pump, the inlet gas flow monitoring device, the washing bottle and the water supply bottle in sequence. The CO2 gas is mixed with water vapor at concentrations of 10% and 5%, enters the inlet 5, and at the same time, ultraviolet light with a wavelength of 365 - 400 nm is transmitted to the catalyst loading surface 8 through the quartz glass 1 with a light source intensity of 500 W / m 2 ;

[0066] Preferably, N2 (nitrogen) gas is introduced while introducing CO2 gas;

[0067] Step 2, the CO2 gas is uniformly introduced onto the catalyst loading surface 8 through the Chinese parasol tree branch uniform flow distribution channel 31 to carry out a photocatalytic reduction reaction with TiO2, obtaining CO (carbon monoxide) and CH3OH (methanol). Among them, there is unreacted CO2 gas in the CO;

[0068] Step 3, the CO and CH3OH are introduced into the outlet 6. The CH3OH enters the collection bottle, and the CO flows through the outlet gas flow monitoring device and is introduced into the two-way gas bag. The unreacted CO2 gas in the CO re-enters the inlet 5 through the two-way gas bag, and step 2 is executed.

[0069] This example demonstrates the application of a multi-stage parasol branch uniform flow gas-solid photocatalytic reactor in the photocatalytic reduction reaction of CO2. Using TiO2 as the catalyst, CO2 is reduced to CO and CH3OH. In the experiment, CO2 gas and water vapor are mixed at concentrations of 10% and 5%, and enter the reactor through the gas input module. In this reactor, the CO2 gas is evenly distributed to the catalyst loading surface 8 through the multi-stage branch channels 32 of the multi-stage parasol branch shunt reaction section. CO2 molecules and water vapor are adsorbed on the active sites on the catalyst surface. This multi-stage parasol branch channel design ensures uniform gas flow on the catalyst surface, maximizes the surface active sites of the catalyst, and avoids the problems of flow channel dead zones and uneven reactant flow rates that may exist in traditional reactors, thus significantly improving the reaction efficiency; the gas with uniform flow rate distribution also improves the utilization rate of the surface active sites of the catalyst, reduces the phenomenon of gas retention or uneven flow, and makes the reaction more stable and efficient.

[0070] Under the conditions of this embodiment, the conversion rate of CO2 reached 82%, the yield of CH3OH produced was 0.18 mmol / g catalyst, and the yield of CO was 0.12 mmol / g catalyst. This achievement is significantly higher than that of traditional photocatalytic reactors, proving the key role of the multi-stage parasol branch channel design in improving the reaction efficiency.

[0071] Through the multi-stage parasol branch channel design, the present invention ensures the uniform distribution of reactant gases on the catalyst surface, thereby maximizing the surface utilization rate of the catalyst. Compared with traditional single-channel reactors, it significantly reduces the problems of uneven gas flow, too fast or too slow flow rates, and avoids the waste of active sites of the catalyst due to insufficient contact of reactants in some areas on the catalyst surface during the reaction process; at the same time, the selectivity of reaction products has also been significantly improved. In this embodiment, the amount of CH3OH produced accounts for 65% of the total products, while CO accounts for 35%. The results show that under the action of the multi-stage parasol branch channels, the generation of by-products during the reaction process is effectively inhibited, and the main products have higher selectivity. The refined control not only improves the efficiency of CO2 reduction, but also provides support for the accurate calculation of the photocatalytic reaction kinetic formula. Through precise gas flow rate distribution and the uniformity of surface reactions on the catalyst, the fluctuations in the reaction rate are minimized, enabling the kinetic formula to more accurately reflect the actual situation of the reaction, providing a theoretical basis for subsequent catalyst optimization and industrial scale application, and laying a foundation for the application of photocatalytic technology in the field of carbon neutrality.

[0072] Example 3:

[0073] See Figure 7 , the present invention provides a multi-stage parasol branch uniform flow gas-solid photocatalytic reaction method, including the following steps:

[0074] Step 1: Place Au / TiO2 (gold-doped titanium dioxide) on the catalyst loading surface 8, and introduce CO2 (carbon dioxide) gas at a flow rate of 1 m / s. The CO2 gas passes through a circulation pump, an inlet flow rate monitoring device, a washing bottle, and a water supply bottle in sequence, and enters the inlet 5. At the same time, a xenon light source (simulating natural light) with a wavelength of 365 - 400 nm is transmitted to the catalyst loading surface 8 through the quartz glass 1 with a light source intensity of 500 W / m 2 ;

[0075] Preferably, N2 (nitrogen) gas is introduced while introducing CO2 gas;

[0076] Step 2: The CO2 gas is evenly introduced onto the catalyst loading surface 8 through the plane tree branch uniform flow distribution channel 31 and undergoes a photocatalytic reduction reaction with Au / TiO2 to obtain CO (carbon monoxide), CH4 (methane), and CH3OH (methanol). Among them, there is unreacted CO2 gas in CO and CH4;

[0077] Step 3: CO, CH4, and CH3OH are introduced into the outlet 6. CH3OH enters the collection bottle, and CO and CH4 flow through the outlet flow rate monitoring device and are introduced into a two-way gas bag. The unreacted CO2 gas in CO and CH4 re-enters the inlet 5 through the two-way gas bag, and Step 2 is executed.

[0078] This embodiment can achieve a CO2 reduction efficiency of 80%, a methanol production of 2.5 mmol / g. Based on the gas distribution design of the plane tree branch uniform flow distribution channel 31, the reaction efficiency on the catalyst surface is greatly improved, and the utilization rate of active sites is increased by more than 30%. Secondly, through the two-way gas bag, a cyclic reaction can be achieved. Compared with traditional parallel flow or single-channel reactors, the overall energy consumption and operating cost of the system are greatly reduced, and the utilization rate of reaction gases is further improved.

[0079] Example 4:

[0080] As Figure 7 shown, the present invention provides a multi-stage plane tree branch uniform flow gas-solid photocatalytic reaction method, including the following steps:

[0081] Step 1: Place Cu / TiO2 (copper-doped titanium dioxide) on the catalyst loading surface 8, and introduce CO2 gas. The CO2 gas passes through a circulation pump, an inlet flow rate monitoring device, a washing bottle, and a water supply bottle in sequence, and enters the inlet 5. At the same time, the sunlight concentrated by a condenser with a wavelength of 365 - 400 nm is transmitted to the catalyst loading surface 8 through the quartz glass 1;

[0082] Preferably, N2 gas is introduced while introducing CO2 gas;

[0083] Step 2: The CO2 gas is evenly introduced onto the catalyst loading surface 8 through the plane tree branch uniform flow distribution channel 31 and undergoes a photocatalytic reduction reaction with Cu / TiO2 to obtain CH4, C2H4 (ethylene), CH3OH, and C2H5OH (ethanol). Among them, there is unreacted CO2 gas in CH4 and C2H4.

[0084] Step 3: CH4, C2H4, CH3OH, and C2H5OH are introduced into the air outlet 6. CH3OH and C2H5OH enter the collection bottle. CH4 and C2H4 flow through the air outlet flow monitoring device and are introduced into the bidirectional air bag. The unreacted CO2 gas in CH4 and C2H4 re-enters the air inlet 5 through the bidirectional air bag, and Step 2 is executed.

[0085] Example 5:

[0086] As Figure 7 shown, the present invention provides a multi-stage plane tree branch uniform flow gas-solid photocatalytic reaction method, including the following steps:

[0087] Step 1: Place W / TiO2 (tungsten-doped titanium dioxide) on the catalyst loading surface 8, introduce CO2 gas, and the CO2 gas sequentially passes through the circulation pump, the air inlet flow monitoring device, the washing bottle, and the water supply bottle, and enters the air inlet 5. At the same time, ultraviolet light with a wavelength of 365 - 400 nm is transmitted to the catalyst loading surface 8 through the quartz glass 1.

[0088] Preferably, N2 gas is introduced while introducing CO2 gas.

[0089] Step 2: The CO2 gas is evenly introduced onto the catalyst loading surface 8 through the plane tree branch uniform flow distribution channel 31 and undergoes a photocatalytic reduction reaction with W / TiO2 to obtain CO and H2 (hydrogen). Among them, there is unreacted CO2 gas in CO and H2.

[0090] Step 3: CO and H2 are introduced into the air outlet 6. CO and H2 flow through the air outlet flow monitoring device and are introduced into the bidirectional air bag. The unreacted CO2 gas in CO and H2 re-enters the air inlet 5 through the bidirectional air bag, and Step 2 is executed.

[0091] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor, characterized in that: It comprises a bottom plate (4), a diverter plate (3) is installed on the top of the bottom plate (4), and an upper cover plate (2) is installed on the top of the diverter plate (3); A catalyst loading surface (8) is installed on the top of the bottom plate (4) for placing the photocatalyst during the experiment; The diverter plate (3) is provided with a through hole (32), the through hole (32) being adapted to the catalyst loading surface (8) and being used for allowing the catalyst loading surface (8) to pass through the through hole (32), and two sides of the through hole (32) are provided with a wutong branch equal flow distribution flow channel (31), the wutong branch equal flow distribution flow channel (31) comprising a main flow channel located at the bottom of the air inlet (5) and the air outlet (6), and a plurality of levels of branch flow channels connected from the main flow channel to the through hole (32), the branch flow channels comprising a mother flow channel, the mother flow channel being connected to a sub-flow channel at a bifurcation, the number of branch flow channels increasing step by step, the diameter of the branch flow channel decreasing step by step, the flow velocity of the branch flow channel decreasing step by step, and the hydraulic diameter and length relationship of the wutong branch equal flow distribution flow channel (31) satisfying the following: Where D is the hydraulic diameter, in mm; L is the length of the flow channel, in mm; n is the number of sub-flow channels at the bifurcation of each branch flow channel; i is the flow channel level of the mother flow channel at the bifurcation of each branch flow channel.

2. A multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to claim 1, characterized in that: The top of the base plate (4) and the bottom of the upper cover plate (2) are respectively provided with sealing grooves (7), and sealing rubber rings are installed in the sealing grooves (7).

3. The multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to claim 1, characterized in that: Said n=2.

4. The multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to claim 1, characterized in that: The upper cover plate (2) is provided with a quartz glass (1), which is located at the top of the through hole (32) and is used to transmit the light source to the catalyst loading surface (8). An air inlet (5) is provided at one end of the upper cover plate (2), and an air outlet (6) is provided at the other end. The air inlet (5) is connected to a water supply bottle, a gas washing bottle, an air inlet flow monitoring device and a circulation pump in sequence through pipelines. The air outlet (6) is connected to a collection bottle and an air outlet flow monitoring device in sequence through pipelines. A two-way air bag is also connected between the circulation pump and the air outlet flow monitoring device through pipelines.

5. The multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to claim 4, characterized in that: The upper cover plate (2) is provided with a light source transmission window (21), and the quartz glass (1) is mounted on the upper cover plate (2) through the light source transmission window (21).

6. The multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to claim 4, characterized in that: A two-way air valve is installed on the two-way air bag.

7. The multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to claim 1, characterized in that: The photocatalyst is titanium dioxide or metal-doped titanium dioxide.

8. A multi-stage sycamore branch uniform flow gas-solid photocatalytic reaction method, based on a multi-stage sycamore branch uniform flow gas-solid photocatalytic reactor according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, placing a photocatalyst on the catalyst loading surface (8), introducing CO2 gas into the air inlet (5), and transmitting a light source through the quartz glass (1) to the catalyst loading surface (8); S2, CO2 gas is uniformly introduced into the catalyst support surface (8) through the sycamore branch uniform flow distribution channel (31) to undergo photocatalytic reduction reaction with the photocatalyst to obtain a gaseous product or a gaseous product and a liquid product, wherein unreacted CO2 gas exists in the gaseous product; S3, the gaseous product and the liquid product are introduced into the gas outlet (6), the gaseous product is introduced into the two-way gas bag, and the unreacted CO2 gas in the gaseous product enters the gas inlet (5) again through the two-way gas bag, and S2 is executed.

9. A multi-stage sycamore branch uniform flow gas-solid photocatalytic reaction method according to claim 8, characterized in that: The air inlet (5) is connected to a water supply bottle, a gas washing bottle, an air inlet flow monitoring device and a circulation pump in sequence through pipelines; the air outlet (6) is connected to a collection bottle and an air outlet flow monitoring device in sequence through pipelines, and a two-way air bag is also connected between the circulation pump and the air outlet flow monitoring device through pipelines.

10. A multi-stage sycamore branch uniform flow gas-solid photocatalytic reaction method according to claim 9, characterized in that: The step of introducing CO2 gas into the air inlet (5) in S1 is as follows: introducing CO2 gas, and the CO2 gas passes through the circulation pump, the air inlet flow monitoring device, the gas washing bottle and the water supply bottle in sequence, and enters the air inlet (5); S3 is as follows: the gaseous product and the liquid product pass into the air outlet (6), the liquid product enters the collecting bottle, the gaseous product flows through the air outlet flow monitoring device and enters the two-way air bag, and the unreacted CO2 gas in the gaseous product enters the air inlet (5) again through the two-way air bag, and S2 is executed.

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