Gas photocatalytic reactor, reaction system and method

Abstract

The invention relates to a gas photocatalytic reactor, a reaction system and a method.The reactor comprises a reactor body, the reactor body is of a bowl-shaped light-transmitting structure with the periphery closed and the interior being a curved-surface cavity, and a catalyst disc is arranged in the curved-surface cavity; the catalyst disc is installed on the inner wall of the bottom of the reactor body through a supporting piece, the bottom of the reactor body is an arc-shaped bottom protruding towards the top of the reactor body, and the curve surface of the inner cavity of the reactor can better utilize a light source; light sources of different incident angles are concentrated on the catalytic reaction surface through transmission and reflection. The unique curved surface design at the bottom of the reactor effectively prevents part of reaction gas from directly flowing out of the outlet without flowing through the catalytic surface, and enhances mass transfer of the catalyst surface, thereby improving the reaction conversion rate.

Description

Technical Field

[0001] The present invention relates to a gas photocatalytic reactor, a reaction system and a method, belonging to the technical fields of energy and chemical engineering. Background Art

[0002] Currently, except for the technologies of enhanced oil recovery in oilfields and carbon dioxide capture from flue gas in coal-fired power plants that have achieved a certain degree of industrialization, carbon dioxide sequestration is in the demonstration stage in China, and most carbon dioxide conversion and utilization technologies are in the laboratory research stage with the lowest industrial maturity. The main reason is that the carbon-oxygen double bond of carbon dioxide has high chemical stability, and a very high energy is required to break the bond energy for conversion. Therefore, in carbon dioxide conversion technologies, using catalysts to reduce the potential energy required for the reaction is one of the main research directions. Photocatalysis is a catalytic conversion reaction technology driven by sunlight. For example, in the process of converting carbon dioxide and water, low-density and intermittent solar energy is converted into high-density and storable clean energy or chemicals, providing a feasible solution for optimizing and transforming the energy consumption structure.

[0003] Currently, the key to promoting the application of light-driven catalytic conversion technology is to improve the conversion efficiency of solar energy. The efficiency of light-driven catalytic reactions is closely related to the light absorption efficiency of the catalyst, the separation efficiency of hole-electron pairs, and the catalytic reaction efficiency. Therefore, to improve the reaction efficiency of photocatalysis, it is very important to design a solar light reaction device with high light utilization rate and high mass transfer efficiency. Currently, the photocatalytic reaction devices on the market can be divided into flat plate type, shallow pool type, tubular and ring type reaction devices according to their structures and shapes, but most of them have key problems such as poor light collection effect, low mass transfer efficiency of reactants on the catalyst surface, internal condensation leading to reduced reaction rate and light scattering, etc. It is necessary to design the reaction surface inside the reaction device and optimize the light path to improve the light utilization rate. At the same time, it is necessary to ensure that the incident light reaches a certain temperature on the catalytic reaction surface to increase the reaction rate and mass transfer efficiency and avoid the occurrence of condensation on the light path. Summary of the Invention

[0004] Aiming at the above technical problems, the present invention provides a gas photocatalytic reactor, a reaction system and a method. The inner cavity curved surface of the reactor can better utilize the light source, and concentrate light sources with different incident angles on the catalytic reaction surface through transmission and reflection. The unique curved surface design at the bottom of the reactor effectively avoids some reaction gases flowing out directly from the outlet without passing through the catalytic surface, enhances the mass transfer on the catalyst surface, and thus improves the reaction conversion rate.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A gas photocatalytic reactor, comprising: The reactor body is a bowl-shaped light-transmitting structure that is enclosed on all sides and has a curved cavity inside. A catalyst disk is arranged in the curved cavity, and the catalyst disk is installed on the inner wall of the bottom of the reactor body through a support. The bottom of the reactor body is an arc-shaped bottom that bulges towards the top of the reactor body.

[0006] In the gas photocatalytic reactor described above, preferably, the catalyst disk is parallel or non-parallel to the top of the reactor body.

[0007] In the gas photocatalytic reactor described above, preferably, the reactor body is further provided with a gas inlet and a gas outlet. The central axis of the gas inlet is at the same height as the thickness midline of the catalyst disk.

[0008] In the gas photocatalytic reactor described above, preferably, the gas outlet is arranged below the vertex of the bottom of the reactor body.

[0009] In the second aspect of the present invention, a gas photocatalytic reaction system is provided, which includes the gas photocatalytic reactor described in any one of the above, and further includes: A light source generator and a static mixer. The light source generator is placed above the reactor body, and the outlet of the static mixer is connected to the inlet of the reactor body; A heat exchanger and a reaction gas separation tank. The outlet of the reactor body is connected to the hot end inlet of the heat exchanger, the inlet of the reaction gas separation tank is connected to the hot end outlet of the heat exchanger, the cold end inlet of the heat exchanger is connected to the water inlet pipeline, and the cold end outlet of the heat exchanger is connected to the first inlet of the static mixer; A gas compressor and a reaction gas cooler. The gas phase outlet of the reaction gas separation tank is connected to the inlet of the gas compressor, and the outlet of the gas compressor is connected to the hot end inlet of the reaction gas cooler; A compressor buffer tank and a membrane separation device. The inlet of the compressor buffer tank is connected to the hot end outlet of the reaction gas cooler, the outlet of the compressor buffer tank is connected to the inlet of the membrane separation device, the permeate end outlet of the membrane separation device is connected to the gas source and the cold end inlet of the reaction gas cooler, the retentate end outlet of the membrane separation device is the gas product, and the cold end outlet of the reaction gas cooler is connected to the second inlet of the static mixer.

[0010] In the gas photocatalytic reaction system described above, preferably, it further includes a buffer tank pressure regulating valve. The inlet of the buffer tank pressure regulating valve is connected to the liquid phase outlet of the compressor buffer tank, and the outlet of the buffer tank pressure regulating valve is connected to the water inlet pipeline.

[0011] In the described gas photocatalytic reaction system, preferably, a temperature measuring device is provided on the pipeline connecting the outlet of the static mixer to the inlet of the reactor body, and the temperature measuring device is used to control the opening or closing of the electric heating of the static mixer according to the measured temperature.

[0012] In the described gas photocatalytic reaction system, preferably, it further includes a check valve. The liquid phase outlet of the reaction gas separation tank is connected to the inlet of the check valve, and the outlet of the check valve is connected to the water inlet pipeline.

[0013] In the described gas photocatalytic reaction system, preferably, a buffer tank safety valve is further provided on the compressor buffer tank.

[0014] The third aspect of the present invention provides a method for using a gas photocatalytic reaction system, including the following steps: The mixed gas to be reacted flows from the static mixer into the reactor body to undergo a photocatalytic reaction to generate product gas. The product gas flows out from the outlet of the reactor body and enters the heat exchanger to exchange heat with the cold fluid in the heat exchanger. The product gas after cooling is separated by the reaction gas separation tank to separate out part of the condensed liquid water, and the liquid water is recycled to the cold end inlet of the heat exchanger; The product gas from which part of the condensed water has been separated is pressurized by the gas compressor and used as the hot fluid of the reaction gas cooler to exchange heat with the cold fluid gas. The cooled product gas enters the compressor buffer tank to further separate the condensed liquid water; The compressed product gas is processed by the membrane separation device, and the gas is separated to the membrane permeation end. After mixing with the supplementary gas, it is preheated as the cold fluid in the reaction gas cooler. The compressed product gas flows out from the outlet of the retention end of the membrane separation device; The gas and water vapor entering the static mixer, after being heated and processed by the static mixer, form a uniformly mixed gas and water vapor, that is, the mixed gas to be reacted.

[0015] Due to the adoption of the above technical solutions, the present invention has the following advantages: 1. The transparent wall surface of the reactor of the present invention has a bowl-shaped curvature. The light source, as the only energy source for the gas photocatalytic reaction, can penetrate the wall surface and reach the circular flat plate surface attached with the photocatalyst. The light penetrating into the reactor can also reach the two side surfaces of the circular flat plate through the reflection of the wall surface curve, improving the light utilization rate (as Figure 2 shown).

[0016] 2. The convex design at the bottom of the reactor of the present invention can not only reflect the light source entering the reactor, increasing the light utilization efficiency, but also improve the path of the gas passing through the reactor. This design can transfer the gas to be reacted to both sides of the circular flat plate (as Figure 3As shown in the figure, the mass transfer efficiency from gas to the catalyst surface is improved, the photocatalytic reaction conversion rate is optimized, and to a certain extent, some gases are prevented from passing through a path far away from the circular flat plate surface of the catalyst and flowing out directly from the outlet without participating in the catalytic reaction.

[0017] 3. The carbon dioxide and water vapor photocatalytic reaction system of the present invention performs secondary heat exchange treatment on the gas at the outlet of the reactor, thereby improving the efficiency of heat utilization. The heat of the reaction product gas is first used to heat water to generate water vapor, and then used to preheat the carbon dioxide gas. The heated carbon dioxide gas and water vapor pass through a pipeline with an electric heating wire before entering the static mixer to ensure that the mixed gas to be reacted is in a gaseous state before entering the photocatalytic reactor. The methane and oxygen products generated by the reaction are mixed with unreacted carbon dioxide and water vapor, and after cooling and water separation, they are compressed by a compressor and enter the carbon dioxide membrane separation module. Carbon dioxide flows out from the permeation side, and the product gas with a certain pressure is mainly methane and oxygen. The product gas can be directly and efficiently utilized, such as oxygen-enriched combustion of methane. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a gas photocatalytic reactor provided by an embodiment of the present invention, wherein FIG a is a stereoscopic diagram and FIG b is a cross-sectional diagram; Figure 2 A schematic diagram of the light path in the gas photocatalytic reactor provided in this embodiment of the present invention; Figure 3 A schematic diagram of gas streamlines in a gas photocatalytic reactor provided in this embodiment of the present invention; Figure 4 A schematic diagram of a system for photocatalytically producing methane from carbon dioxide and water vapor provided in this embodiment of the present invention; The reference numerals in the figures are as follows: 1-reactor body; 2-light source generator; 3-heat exchanger; 4-reaction gas separation tank; 5-reaction gas cooler; 6-gas compressor; 7-compressor buffer tank; 8-membrane separation device; 9-static mixer; 10-buffer tank pressure regulating valve; 11-buffer tank safety valve; 12-temperature measuring device; 13-check valve; 101 - catalyst disc, 102 - gas inlet, 103 - gas outlet, 104 - disc support column, 105 - arc-shaped bottom. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0020] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second", "third", "fourth" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or items appearing before this term cover the elements or items listed after this term and their equivalents, without excluding other elements or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0021] For the sake of convenience of description, spatial relative relationship terms may be used in the text to describe the relationship of one element or feature shown in the figure relative to another element or feature. Such relative relationship terms are, for example, "inner", "outer", "inside", "outside", "below", "above", etc. Such spatial relative relationship terms are intended to include different orientations of the device in use or operation in addition to the orientations depicted in the figure.

[0022] Currently, the key to promoting the application of the light-driven catalytic conversion technology is to improve the conversion efficiency of solar energy. The efficiency of the light-driven catalytic reaction is closely related to the light absorption efficiency of the catalyst, the separation efficiency of the hole-electron pairs and the catalytic reaction efficiency. Therefore, in order to improve the reaction efficiency of photocatalysis, it is very important to design a solar reaction device with high light utilization rate and high mass transfer efficiency. The current photocatalytic reaction devices on the market can be divided into flat plate type, shallow pool type, tubular and annular reaction devices according to their structures and shapes, but most of them have key problems such as poor light concentration effect, low mass transfer efficiency of the reactants on the catalyst surface, reduction of the reaction rate caused by internal condensation and light scattering, etc. It is necessary to design the reaction surface in the reaction device and optimize the light path to improve the light utilization rate. At the same time, it is necessary to ensure that the incident light reaches a certain temperature on the catalytic reaction surface to increase the reaction rate and mass transfer efficiency and avoid the occurrence of condensation on the light path.

[0023] Based on the above technical problems, the present invention provides a gas photocatalytic reactor. The reactor with a bowl-shaped design has a light-transmitting wall surface, which can ensure that the light source can penetrate the reactor and enter its interior to provide the energy required for the photocatalytic reaction. Through computational fluid dynamics verification and optimization, the flow characteristics of the gas inside the reactor are obtained.

[0024] As Figure 1As shown in the figure, the gas photocatalytic reactor involved in the present invention includes: a reactor body 1, the reactor body 1 is a bowl-shaped structure with a closed perimeter and a cavity inside. A catalyst disk 101 is arranged in the cavity. The catalyst disk 101 is installed on the inner wall of the bottom of the reactor body 1 through a disk support column 104. The bottom of the reactor body 1 is an arc-shaped bottom 105 that bulges towards the top of the reactor body 1. A gas inlet 102 and a gas outlet 103 are also provided on the reactor body 1. The central axis of the pipeline of the gas inlet 102 is at the same height as the thickness midline of the catalyst disk 101. The wall surface of the reactor body 1 is made of a light-transmitting material. Photocatalysts are attached to both sides of the catalyst disk 101. The catalyst disk 101 is located at the position of the convex vertex at the bottom of the reactor body 1 and is fixed by the disk support column 104. The gas outlet 103 is arranged below the vertex of the convex bottom 105. The design of the cavity can effectively reduce the velocity of the reaction gas in the inlet pipeline and disperse the reaction gas on both sides of the catalyst disk 101. The cavity curved surface can project incident light at different angles and then reflect it onto the catalyst disk 101, improving the light utilization efficiency. The gas photocatalytic reactor of the present invention internally includes a circular flat plate with catalysts attached to both the front and back sides, and a curved cavity. The design of the cavity can effectively reduce the velocity of the reaction gas in the inlet pipeline and disperse the reaction gas on both sides of the catalyst flat plate. The cavity curved surface can project incident light at different angles and then reflect it onto the catalyst flat plate, improving the light utilization efficiency.

[0025] Specifically, as Figure 2 shown, the uniformly mixed reaction gas enters the cavity of the reactor from the gas inlet 102. The center line of the inlet pipeline coincides with the midline of the height of the catalyst disk 101. The reaction gas is dispersed on both sides of the catalyst disk 101 attached with catalysts. The light source can be incident into the reactor from different angles. The light source is a yellow straight line with an arrow, and the arrow direction represents the incident direction of the light source. The straight line with a red arrow represents the transmitted light. After entering the reactor, a part of it directly irradiates on the catalyst disk 101; another part, due to the reflection effect of the cavity curved surface of the device, reflects the transmitted light and then irradiates on the catalyst disk 101. The reflected light is represented by a straight line with a green arrow. The light irradiating on the catalyst surface can be absorbed by the plasmon light-absorbing unit of the catalyst, and the energy is transmitted to the catalytically active metal atomic sites. The reaction gas undergoes corresponding catalytic reactions at the catalytic sites to generate reaction products. Under the dual thermal effects of the light source and the reaction, the reaction products need to be gaseous; otherwise, it will affect the propagation of light in the reactor and reduce the light use efficiency. The reaction gas products and the unreacted reaction gas flow out of the photocatalytic reactor from the gas outlet 103.

[0026] As Figure 3As shown in the figure, the gas photocatalytic reactor is verified by means of computational fluid dynamics simulation, with a uniform mixed gas of carbon dioxide and water vapor, the molar ratio is 1:1, at 200°C and 1 atmosphere, and the flow trajectory of the mixed gas in the photocatalytic reactor. The simulation results show that the gas in the photocatalytic reactor is evenly distributed on both sides of the catalytic disc 101. Since the position of the gas outlet 103 is far away from the gas inlet 102, there is no obvious path connecting the gas inlet 102 and the gas outlet 103. This design can improve the gas mass transfer efficiency and reaction conversion rate.

[0027] The gas photocatalytic reaction system can produce methane by photocatalytic reaction of carbon dioxide and water vapor. The chemical reaction equation is as follows: .

[0028] The gas photocatalytic reactor involved in the present invention is used for catalytic reaction of gas in the reactor under the action of light, and a special bowl-shaped reactor with an arc bottom is designed. The light source is incident into the reactor at different angles, and is reflected by the curved wall and the arc bottom, which can improve the efficiency of light use. Due to the special arc bottom design, it is beneficial for the gas to be reacted to be transferred to the catalyst surface, thereby achieving the effect of optimizing mass transfer and improving the reaction rate.

[0029] like Figure 4 As shown, the present invention also provides a carbon dioxide and water vapor photocatalytic methane production system including a gas photocatalytic reactor, the system including: a reactor body 1, a light source generator 2, a heat exchanger 3, a reaction gas liquid separation tank 4, a reaction gas cooler 5, a gas compressor 6, a compressor buffer tank 7, a membrane separation device 8, a static mixer 9, etc.

[0030] Specifically, the water inlet pipeline is respectively connected to the outlet of the buffer tank pressure regulating valve 10, the cold-end inlet of the heat exchanger 3, and the outlet of the check valve 13; the cold-end outlet of the heat exchanger 3 is connected to the inlet of the static mixer 9 with electric heating; the outlet of the static mixer 9 is connected to the inlet of the reactor body 1, and a temperature measuring device 12 is connected to this pipeline to control the opening or closing of the electric heating of the static mixer 9 according to the measured temperature; the light source generator 2 is placed near the reactor body 1, and the position of the light source generator 2 is adjusted according to the light intensity; the outlet of the reactor body 1 is connected to the hot-end inlet of the heat exchanger 3; the hot-end outlet of the heat exchanger 3 is connected to the inlet of the reaction gas separation tank 4; the liquid-phase outlet of the reaction gas separation tank 4 is connected to the inlet of the check valve 13; the gas-phase outlet of the reaction gas separation tank 4 is connected to the inlet of the gas compressor 6; the outlet of the gas compressor 6 is connected to the hot-end inlet of the reaction gas cooler 5; the hot-end outlet of the reaction gas cooler 5 is connected to the inlet of the compressor buffer tank 7; the liquid-phase outlet of the compressor buffer tank 7 is connected to the inlet of the buffer tank pressure regulating valve 10; the gas-phase outlet of the compressor buffer tank 7 is connected to the inlet of the membrane separation device 8; the top of the compressor buffer tank 7 is connected to the inlet of the buffer tank safety valve 11; the outlet of the buffer tank safety valve 11 is connected to the atmosphere; the permeate-end outlet of the membrane separation device 8 is connected to the carbon dioxide gas source and the cold-end inlet of the reaction gas cooler 5; the retentate-end outlet of the membrane separation device 8 is the gas product; the cold-end outlet of the reaction gas cooler 5 is connected to the other inlet of the static mixer 9.

[0031] Furthermore, as Figure 4 shown, the present invention also provides the working process of the carbon dioxide and water vapor photocatalytic methane production system, and the specific process is as follows: The uniformly mixed carbon dioxide and water vapor flow into the reactor body 1 from the static mixer 9. Under the action of the light generated by the light source generator 2, a photocatalytic reaction occurs on the surface of the catalyst in the reactor body 1, converting into gaseous methane and oxygen. The produced methane and oxygen are mixed with the unreacted carbon dioxide and water vapor, and are heated under the thermal effect of light, flowing out from the gas outlet 102 of the reactor body 1, serving as the hot fluid of the heat exchanger 3 to heat the cold fluid (i.e., the water additionally supplemented to the system). The cooled product gas passes through the reaction gas liquid separation tank 4 to separate out part of the condensed liquid water. The condensed water circulates to the cold end inlet of the heat exchanger 3 through the check valve 13. The product gas from which part of the condensed water has been separated is pressurized by the gas compressor 6 and serves as the hot fluid of the reaction gas cooler 5 to exchange heat with the cold fluid carbon dioxide. The cooled product gas enters the compressor buffer tank 7 to further separate the condensed liquid water. The condensed water is depressurized by the buffer tank pressure regulating valve 10 and then circulates to the cold end inlet of the heat exchanger 3. The compressed product gas is processed by the membrane separation device 8 to separate carbon dioxide to the membrane permeation end at atmospheric pressure. After being mixed with the supplemented carbon dioxide gas, it is preheated as the cold fluid in the reaction gas cooler 5. The compressed product gas flows out from the outlet of the retention end of the membrane separation device 8, and its main components are methane and oxygen. The compressed product gas of methane and oxygen can be directly used as the fuel gas for oxy-fuel combustion. The carbon dioxide gas and water vapor entering the static mixer 9 are heated by the electric heating wire and processed by the static mixer 9 to form uniformly mixed carbon dioxide and water vapor, that is, the mixed gas to be reacted. The temperature measuring device 12 instantaneously records the temperature of the mixed gas and ensures that the mixed fluid is in a gaseous state according to the temperature. When the temperature is less than or equal to the dew point of the mixed gas, the electric heating system in the static mixer 9 is started. When the temperature of the mixed gas is more than 10 degrees above the dew point, the electric heating system in the static mixer 9 is turned off.

[0032] Based on safety considerations, a buffer tank safety valve 11 is designed for the compressor buffer tank 7. When an abnormal situation of excessive pressure occurs, the buffer tank safety valve 11 opens and alarms. In addition, a check valve 13 is set at the liquid phase outlet of the reaction gas liquid separation tank 4 to ensure the flow direction of the condensed water and the supplemented water, and to prevent the unreacted liquid water from directly flowing into the reaction gas liquid separation tank 4.

[0033] The design of the gas photocatalytic reactor and reaction system of the present invention is original. Based on the design of a bowl-shaped reactor with a convex bottom, after the light source penetrates the reactor wall, the light entering the reactor can be reflected by the curved wall to the surface of the catalyst disk, improving the light utilization efficiency. Catalysts required for the reaction are attached to both sides of the disk, and the gas to be reacted can more conveniently flow through the surface of the disk by virtue of the convex bottom design, thereby optimizing mass transfer and reaction conversion rate. Based on the gas photocatalytic reactor, the present invention designs a system for photocatalytic production of methane from carbon dioxide and water vapor. While optimizing the thermal efficiency, it incorporates a carbon dioxide membrane separation device and a condensate water circulation design, saving the usage amount of reactants. The gas products are compressed methane and oxygen, which can be directly used for oxy-fuel combustion of methane.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended 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 recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas photocatalytic reactor, characterized in that, Comprising: A reactor body (1), the reactor body (1) being a bowl-shaped light-transmitting structure that is enclosed on all sides and has a curved cavity inside. A catalyst disk (101) is arranged in the curved cavity, and the catalyst disk (101) is installed on the bottom inner wall of the reactor body (1) through a support. The bottom of the reactor body (1) is an arc-shaped bottom (105) that protrudes towards the top of the reactor body (1).

2. The gas photocatalytic reactor according to claim 1, characterized in that, The catalyst disk (101) is parallel or non-parallel to the top of the reactor body (1).

3. The gas photocatalytic reactor according to claim 1, wherein A gas inlet (102) and a gas outlet (103) are further arranged on the reactor body (1). The central axis of the gas inlet (102) is at the same height as the thickness median line of the catalyst disk (101).

4. The gas photocatalytic reactor according to claim 1, wherein The gas outlet (103) is arranged below the vertex of the bottom of the reactor body (1).

5. A gas photocatalytic reaction system, characterized in that, Comprising the gas photocatalytic reactor according to any one of claims 1-4, further comprising: A light source generator (2) and a static mixer (9). The light source generator (2) is placed above the reactor body (1), and the outlet of the static mixer (9) is connected to the inlet of the reactor body (1); A heat exchanger (3) and a reaction gas separation tank (4). The outlet of the reactor body (1) is connected to the hot-end inlet of the heat exchanger (3), the inlet of the reaction gas separation tank (4) is connected to the hot-end outlet of the heat exchanger (3), the cold-end inlet of the heat exchanger (3) is connected to a water inlet pipeline, and the cold-end outlet of the heat exchanger (3) is connected to the first inlet of the static mixer (9); A gas compressor (6) and a reaction gas cooler (5). The gas-phase outlet of the reaction gas separation tank (4) is connected to the inlet of the gas compressor (6), and the outlet of the gas compressor (6) is connected to the hot-end inlet of the reaction gas cooler (5); A compressor buffer tank (7) and a membrane separation device (8). The inlet of the compressor buffer tank (7) is connected to the hot-end outlet of the reaction gas cooler (5), the outlet of the compressor buffer tank (7) is connected to the inlet of the membrane separation device (8), the permeate-end outlet of the membrane separation device (8) is connected to a gas source and the cold-end inlet of the reaction gas cooler (5), the retentate-end outlet of the membrane separation device (8) is a gas product, and the cold-end outlet of the reaction gas cooler (5) is connected to the second inlet of the static mixer (9).

6. The gas photocatalytic reaction system according to claim 5, characterized in that A buffer tank pressure regulating valve (10) is further included. The inlet of the buffer tank pressure regulating valve (10) is connected to the liquid-phase outlet of the compressor buffer tank (7), and the outlet of the buffer tank pressure regulating valve (10) is connected to the water inlet pipeline.

7. The gas photocatalytic reaction system according to claim 5, characterized in that A temperature measuring device (12) is arranged on the pipeline where the outlet of the static mixer (9) is connected to the inlet of the reactor body (1). The temperature measuring device (12) is used to control the opening or closing of the electric heating of the static mixer (9) according to the measured temperature.

8. The gas photocatalytic reaction system according to claim 5, characterized in that, It further includes a check valve (13). The liquid phase outlet of the reaction gas separation tank (4) is connected to the inlet of the check valve (13), and the outlet of the check valve (13) is connected to the water inlet pipeline.

9. The gas photocatalytic reaction system according to claim 5, wherein, A buffer tank safety valve (11) is further provided on the compressor buffer tank (7).

10. A method for using the gas photocatalytic reaction system according to any one of claims 5-9, characterized in that, It includes the following steps: The mixed gas to be reacted flows into the reactor body (1) from the static mixer (9) to undergo a photocatalytic reaction to generate product gas. The product gas flows out of the outlet of the reactor body (1) and enters the heat exchanger (3) to exchange heat with the cold fluid in the heat exchanger (3). The cooled product gas separates part of the condensed liquid water through the reaction gas separation tank (4), and the liquid water is circulated to the cold end inlet of the heat exchanger (3); The product gas from which part of the condensed water is separated is pressurized by the gas compressor (6) and serves as the hot fluid of the reaction gas cooler (5) to exchange heat with the cold fluid gas. The cooled product gas enters the compressor buffer tank (7) to further separate the condensed liquid water; The compressed product gas is processed by the membrane separation device (8), and the gas is separated to the membrane permeation end. After being mixed with the supplementary gas, it is preheated as the cold fluid in the reaction gas cooler (5). The compressed product gas flows out from the outlet of the retention end of the membrane separation device (8); The gas and water vapor entering the static mixer (9) form a uniformly mixed gas and water vapor, that is, the mixed gas to be reacted, after being heated and processed by the static mixer (9).

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