A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system

Abstract

The application discloses a continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system, which comprises a reaction kettle, a reactor, a heat exchanger, a large micro-nano bubble generating device and a small micro-nano bubble generating device. The reaction kettle is provided with a feeding opening, a gas-liquid inlet, a gas phase outlet and a liquid phase product outlet. The gas-liquid inlet of the reaction kettle is connected with the outlet of the large micro-nano bubble generating device. The liquid phase product outlet of the reaction kettle is connected with the inlet of the heat exchanger and an extraction valve. The outlet of the heat exchanger is connected with the inlet of the large micro-nano bubble generating device. The outlet of the extraction valve is connected with the inlet of the small micro-nano bubble generating device. The outlet of the small micro-nano bubble generating device is connected with the bottom end of the reactor. The reactor is provided with a product outlet which is connected with a product valve. The application can ensure the continuous chemical reaction, the uniform dispersion of the gas-liquid-solid three-phase, the high conversion rate of the gas-liquid two-phase reaction, the avoidance of the solid catalyst into the circulating pump and the guarantee of the reaction activity of the catalyst.

Description

Technical Field

[0001] This utility model relates to the field of chemical production, and in particular to a continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system. Background Technology

[0002] Gas-liquid-solid three-phase reactions are common in the chemical industry, with many types. In most cases, the solid phase acts as the catalyst, while the gas and liquid phases are the reactants and products. Back-mixed reactors, such as loop reactors, have advantages such as good mass transfer, large external heat exchange area, and good sealing, and are widely used in gas-liquid two-phase reactions. A common loop reactor consists of a reaction vessel, heat exchanger, Venturi ejector, loop circulation pump, and circulation pipeline. Its principle is to use a high-speed flowing phase to entrain other phases, ensuring close contact between the phases, followed by uniform dispersion or suspension within the reactor, thus completing the reaction. During operation, the circulation pump sends the reaction liquid into the Venturi ejector, forming a rapid jet stream through the nozzle. Gas is ejected from the gas-carrying chamber, and the liquid impacts the tube wall, mixing and reacting thoroughly. In this region, intense turbulence enables the gas and liquid to complete the initial major mass transfer function. The gas-liquid two-phase mixture is then injected into the reaction vessel, where secondary mixing and reaction continue. However, back-mixed reactors are difficult to use for continuous reactions with high product conversion rates. Furthermore, solid catalysts exhibit poor dispersion within the reactor, are easily mixed into the circulating pump, and are prone to breakage and deactivation under the high shear effect of the circulating pump, limiting the application of gas-liquid-solid three-phase reactions in traditional loop reactors. In addition, fixed-bed reactors suffer from poor gas-liquid mixing and low mass and heat transfer rates, limiting the application of continuous gas-liquid-solid three-phase high-conversion reactions. Utility Model Content

[0003] In view of the shortcomings and defects in the existing technology, this utility model provides a continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system. This reaction system can ensure the continuous progress of chemical reaction, uniform dispersion of gas, liquid and solid phases, high conversion rate of gas-liquid two-phase reaction, avoid solid catalyst entering the circulation pump, and ensure the reaction activity of catalyst.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system includes a reaction vessel, a reactor, a heat exchanger, a large-scale nano-bubble generator, and a small-scale nano-bubble generator. The reaction vessel has a feed port at the top and a gas-liquid inlet at the bottom. A gas phase outlet and a liquid phase product outlet are provided between the feed port and the gas-liquid inlet, with the gas phase outlet located above the liquid phase product outlet. The gas-liquid inlet of the reaction vessel is connected to the outlet of the large-scale nano-bubble generator. The liquid phase product outlet of the reaction vessel is connected to the inlet of the heat exchanger and a product outlet valve. The outlet of the heat exchanger is connected to the inlet of the large-scale nano-bubble generator. The outlet of the product outlet valve is connected to the inlet of the small-scale nano-bubble generator. The outlet of the small-scale nano-bubble generator is connected to the bottom of the reactor. A product outlet is provided in the upper middle part of the reactor and is connected to a product valve.

[0005] Furthermore, the gas-liquid inlet of the reactor is connected to the outlet of the first check valve, and the inlet of the first check valve is connected to the raw material inlet valve and the outlet of the large micro-nano bubble generator.

[0006] Furthermore, the gas phase outlet of the reactor is connected to the inlet of the second check valve, the top gas phase outlet of the heat exchanger is connected to the inlet of the third check valve, the top gas phase outlet of the reactor is connected to the fourth check valve, and the outlets of the second, third, and fourth check valves are respectively connected to the gas supply pipeline.

[0007] Furthermore, the large micro-nano bubble generator includes a circulation pump A, a micro-nano bubble generator A, and an air inlet pipe A, while the small micro-nano bubble generator includes a circulation pump B, a micro-nano bubble generator B, and an air inlet pipe B. The air inlet pipe A and the air inlet pipe B are respectively connected to an air circuit valve, and the air circuit valve is connected to an air supply device.

[0008] Furthermore, both the micro-nano bubble generator A and the micro-nano bubble generator B include a housing and a generating column installed inside the housing. The housing has a gas-liquid inlet and a gas-liquid outlet. The gas-liquid mixture entering from the gas-liquid inlet flows through the generating column and then flows out from the gas-liquid outlet. The generating column includes multiple bubble cutting units. The surface of the bubble cutting unit is provided with a flow channel, and there are pressure-reducing grooves between the bubble cutting units.

[0009] Preferably, the flow channel is a spiral flow channel.

[0010] Preferably, the inflow end of the bubble cutting unit has a serrated surface.

[0011] Preferably, the front end of the bubble cutting unit at the gas-liquid inlet is provided with an impact platform.

[0012] Preferably, the impact platform is a multi-stage frustum, and the impact platform, the bubble cutting unit, and the gas-liquid inlet are coaxially arranged.

[0013] Preferably, the housing includes an outer shell and an inner shell, the generating column is disposed in the inner shell cavity, the two ends of the inner shell are respectively provided with a gas-liquid inlet and a gas-liquid outlet, the outer shell cavity is provided with a gas chamber, the gas inlet of the gas chamber is disposed on the outer shell, and the gas outlet of the gas chamber is connected to the inner shell cavity.

[0014] Preferably, the air inlet of the air chamber is located in the upper middle part of the outer shell, and the air outlet of the air chamber is located at the gas-liquid outlet.

[0015] Preferably, the gas-liquid inlet includes a gradually decreasing volume funnel-shaped section and a cylindrical section, with the diameter of the generating column being larger than the diameter of the cylindrical section but smaller than the maximum diameter of the funnel-shaped section.

[0016] Preferably, the gas-liquid outlet is a gradually expanding funnel shape, and the end of the generating column has a truncated cone section with a gradually increasing diameter, the diameter of which is smaller than the diameter of the bubble cutting unit.

[0017] Furthermore, a feed valve is provided between the large micro-nano bubble generator and the reaction vessel.

[0018] Furthermore, the reactor is a tubular reactor with an external jacket for heat exchange.

[0019] Furthermore, during the continuous operation of the reaction system, the feed rate of the feed valve, the output rate of the output valve, and the output rate of the product valve should be the same.

[0020] Furthermore, the interior of the reaction vessel and the reactor are respectively provided with a supported catalyst, which is arranged vertically, horizontally, or spirally inside the reaction vessel.

[0021] The beneficial effects of this utility model are: (1) The reactor, heat exchanger, large micro-nano bubble reaction device, small micro-nano bubble reaction device and reactor are connected to form a circulation loop, which is conducive to gas-liquid two-phase or gas-liquid-solid three-phase reaction. During the reaction, the flow rates of the feed valve, the outlet valve and the product valve are controlled to be the same, so as to realize continuous reaction; (2) The gas and liquid components enter the reactor through the large micro-nano bubble reaction device and enter the reactor through the small micro-nano bubble reaction device. Compared with macro bubbles, the micro-nano bubble generated by the micro-nano bubble generator has the advantages of large specific surface area, high activity, fast mass transfer rate and long residence time, which can promote the uniform dispersion and efficient reaction of gas-liquid two-phase or gas-liquid-solid three-phase reaction; the coupling of the reactor and the reactor can improve the reaction conversion rate; (3) During the gas-liquid-solid three-phase reaction, the reactor and the reactor are loaded with catalysts respectively. The solid catalyst is in full contact with the gas-liquid reactants, the catalytic effect is good, and the catalyst is not easy to enter the circulation pump, which can ensure the reaction activity of the catalyst. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of this utility model.

[0024] Figure 2 This is a schematic diagram of a preferred micro / nano bubble generator.

[0025] Figure 3 yes Figure 2 Enlarged view of a portion of point A in the middle.

[0026] Figure 4 This is a schematic diagram of the column structure.

[0027] Figure 5 This is a schematic diagram of the shell structure.

[0028] Figure 6 This is a comparison chart of the mass transfer effects of different bubbles.

[0029] Figure 7 This is a schematic diagram of a fully converted reaction system using a preferred micro / nano bubble generator.

[0030] In the diagram: 1. Reactor; 11. Supported catalyst; 12. Gas-liquid inlet; 13. Liquid product outlet; 14. Gas outlet; 15. Feed port; 21. First check valve; 22. Second check valve; 23. Third check valve; 24. Fourth check valve; 3. Feed valve; 41. Large / micro / nano bubble generator; 411. Circulation pump A; 412. Micro / nano bubble generator A; 413. Inlet pipe A; 42. Small / micro / nano bubble generator; 421. Circulation pump B; 422. Micro / nano bubble generator B; 423. Inlet pipe B. 431 Generating column, 4311 Bubble cutting unit, 4312 Flow channel, 4313 Serrated surface, 4314 Pressure reducing groove, 4315 Impact platform, 4316 Frustum section, 432 Shell, 4321 Outer shell, 4322 Inner shell, 4323 Gas-liquid inlet, 43231 Trumpet section, 43232 Cylindrical section, 4324 Gas-liquid outlet, 433 Gas chamber, 4331 Inlet, 4332 Outlet, 5 Production valve, 6 Gas valve, 7 Heat exchanger, 71 Gas phase outlet, 8 Reactor, 81 Loaded catalyst, 82 Gas phase outlet, 83 Feed port, 9 Product valve, 10 Gas supply pipeline. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] Example 1 This utility model discloses a continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system, including a reaction vessel 1, a reactor 8, a heat exchanger 7, a large micro-nano bubble generator 41, and a small micro-nano bubble generator 42. The reaction vessel 1 is provided with a feed port 15 at the top and a gas-liquid inlet 12 at the bottom. A gas phase outlet 14 and a liquid phase product outlet 13 are provided between the feed port 15 and the gas-liquid inlet 12, with the gas phase outlet 14 located above the liquid phase product outlet 13. The gas-liquid inlet 12 of the reaction vessel 1 is connected to the outlet of the large micro-nano bubble reaction device. The liquid phase product outlet 13 of the reaction vessel 1 is connected to the inlet of the heat exchanger 7 and the outlet valve 5. The outlet of the heat exchanger 7 is connected to the inlet of the large micro-nano bubble reaction device. The outlet of the outlet valve 5 is connected to the inlet of the small micro-nano bubble generator 42. The outlet of the small micro-nano bubble generator 42 is connected to the bottom end of the reactor 8. A product outlet is provided in the upper middle part of the reactor 8, and the product outlet is connected to the product valve 9. The reaction vessel 1 and the reactor 8 are used together. After the reactants have initially reacted in the reaction vessel 1 and reached the expected conversion rate, the outlet valve 5 is opened and the material enters the reactor 8 for further reaction. When the complete conversion is reached, the product valve 9 is opened to discharge the product.

[0034] The gas-liquid inlet 12 of reactor 1 is connected to the outlet of the first check valve 21, and the inlet of the first check valve 21 is connected to the raw material inlet valve and the outlet of the large and micro nano bubble generator 41. The first check valve 21 ensures that the material flows in one direction at the gas-liquid inlet 12 of reactor 1 and prevents backflow.

[0035] The gas phase outlet 14 of reactor 1 is connected to the inlet of the second check valve 22, the top gas phase outlet 71 of heat exchanger 7 is connected to the inlet of the third check valve 23, and the top gas phase outlet 82 of reactor 8 is connected to the fourth check valve 24. The outlets of the second check valve 22, the third check valve 23, and the fourth check valve 24 are respectively connected to the gas supply pipeline 10. The gas discharged through the second check valve 22, the third check valve 23, and the fourth check valve 24 re-enters the large micro-nano bubble generator 41 or the small micro-nano bubble generator 42 through the gas supply pipeline, and then enters the reactor 1 or reactor 8 to continue the reaction, thereby improving the gas conversion rate.

[0036] The large-scale micro-nano bubble generator 41 includes a circulation pump A411, a micro-nano bubble generator A412, and an air inlet pipe A413, which is connected to a gas valve 6. The small-scale micro-nano bubble generator 42 includes a circulation pump B421, a micro-nano bubble generator B422, and an air inlet pipe B423, which is connected to the gas valve 6. The gas valve 6 is connected to a gas supply device. Circulation pumps A411 and B421 provide power to the micro-nano bubble generators A412 and B422, as well as the gas-liquid circulation. The gas supply device provides gaseous raw materials to the reaction vessel 1 and the reactor 8.

[0037] The liquid phase circulation rates of the large-scale nanobubble generator 41 and the small-scale nanobubble generator 42 are different. The liquid phase circulation rate of the large-scale nanobubble generator 41 is several to tens of times that of the small-scale nanobubble generator 42. The gas intake rate of the large-scale nanobubble generator 41 is the maximum gas intake rate that the reaction system can withstand. The gas intake rate of the small-scale nanobubble generator 42 is related to the liquid phase circulation rate and the conversion rate set by the extraction valve 5. The higher the conversion rate, the lower the gas intake rate and liquid phase circulation rate of the small-scale nanobubble generator 42.

[0038] A feed valve 3 is provided between the large / micro / nano bubble generator 41 and the reaction vessel 1. The feed valve 3 can replenish liquid reactants to the reaction system.

[0039] The reactor 8 is a tubular reactor with an external jacket for heat exchange. A heat exchange fluid is introduced into the jacket to exchange heat with the substances inside the reactor 8. A feed port 83 is also provided at the top of the reactor 8 for adding materials to the reactor 8.

[0040] During continuous operation of the reaction system, the feed rate of feed valve 3, the output rate of output valve 5, and the output rate of product valve 9 should be the same.

[0041] In addition, both reactor 1 and reactor 8 should be equipped with pressure gauges and safety valve ports.

[0042] Example 2 The difference between Example 2 and Example 1 is that: The reactor 1 is equipped with a supported catalyst 11, which is arranged vertically, horizontally, or spirally inside the reactor 1. The reactor 8 is equipped with a supported catalyst 81, which is also arranged vertically, horizontally, or spirally inside the reactor 8. Example 1 is suitable for gas-liquid two-phase reactions, while Example 2, by using supported catalysts in the reactor 1 and reactor 8, is suitable for gas-liquid-solid three-phase reactions. Using supported catalysts increases the contact area between the catalyst and the reactants, improving catalytic efficiency. Simultaneously, the catalyst is less likely to enter the circulating pump, thus ensuring the catalyst's reactivity.

[0043] In operation, the reaction system of this invention involves opening the feed valve 3 and / or adding liquid raw materials to the reactor 1 and heat exchanger 7 through the feed port 15. The liquid level of the raw materials should cover the loaded catalyst 11 in the reactor 1, leaving some space for the gas phase. The feed valve 3 and feed port 15 are then closed, and the large / micro / nano bubble generator 41 is turned on to allow the gas-liquid two-phase or gas-liquid-solid three-phase reaction to proceed fully in the reactor 1 until the conversion rate of the raw materials reaches the conversion rate requirement set by the outlet valve 5 (the conversion rate of the product at the outlet valve 5 is generally set to above 80%). The feed valve 3, outlet valve 5, product valve 9, and small / micro / nano bubble generator 42 are then opened, allowing the gas-liquid two-phase or gas-liquid-solid three-phase reaction to proceed fully in the reactor 8 until the conversion rate reaches the conversion rate requirement set by the product valve 9 (the conversion rate of the product valve 9 is set according to actual requirements; for a reactant requiring complete conversion, the conversion rate can be set to 100%). The product flows out from the product valve 9, thus achieving a continuous gas-liquid-solid three-phase reaction. Example 3 The structures of micro-nano bubble generators A412 and B422 in the large micro-nano bubble generator 41 and the small micro-nano bubble generator 42 can be adopted as follows: Figure 2 The aforementioned micro / nano bubble generator, and the reaction system using this preferred micro / nano bubble generator, are as follows: Figure 7 As shown, the micro / nano bubble generator includes a housing 432 and a generating column 431 installed within the housing 432. The housing 432 has a gas-liquid inlet 4323 and a gas-liquid outlet 4324. The gas-liquid mixture entering from the gas-liquid inlet 4323 flows through the generating column 431 and exits from the gas-liquid outlet 4324. The generating column 431 includes multiple bubble-cutting units 4311. The surface of the bubble-cutting unit 4311 is provided with flow channels 4312, and there are pressure-reducing grooves 4314 between the bubble-cutting units 4311. Under the action of the bubble-cutting units 4311, the gas-liquid mixture is sheared, stirred, and dispersed, and enters the annular pressure-reducing groove 4314. Because the cross-sectional area of ​​the fluid passage cavity at the pressure-reducing groove 4314 increases, the pressure is reduced, releasing the dissolved gas in the liquid and continuously generating micro / nano-sized bubbles.

[0044] In this embodiment, the flow channel 4312 is a spiral flow channel 4312. When the fluid flows through the spiral flow channel 4312, the spiral structure causes the gas and liquid two-phase fluid to rotate. The gas and liquid are continuously sheared, stirred and dispersed within the flow channel 4312. Compared with a straight channel, the spiral flow channel can significantly improve the uniformity of gas-liquid mixing.

[0045] The inflow end of the bubble cutting unit 4311 is provided with a serrated surface 4313, see [reference]. Figure 2 and Figure 3 Serrated surfaces can increase impact and convection effects.

[0046] The front end of the bubble cutting unit 4311 at the gas-liquid inlet 4323 is provided with an impact platform 4315. The impact platform 4315 is a multi-stage frustum, and the impact platform 4315, the bubble cutting unit 4311, and the gas-liquid inlet 4323 are coaxially arranged. The impact platform 4315 impacts and collides with the fluid entering through the gas-liquid inlet 4323 to generate convection, enhancing the gas-liquid mixing effect; under the action of the impact force, the bubbles will split into multiple smaller bubbles.

[0047] See Figure 2 and Figure 5 The housing 432 includes an outer shell 4321 and an inner shell 4322. A generating column 431 is disposed within the cavity of the inner shell 4322. The inner shell 4322 has a gas-liquid inlet 4323 and a gas-liquid outlet 4324 at its two ends, respectively. An outer shell 4321 contains a gas chamber 433. The inlet 4331 of the gas chamber 433 is located on the outer shell 4321, and the outlet 4332 of the gas chamber 433 communicates with the cavity of the inner shell 4322. The inlet 4331 of the gas chamber 433 is located in the upper middle part of the outer shell 4321, and the outlet 4332 of the gas chamber 433 is located at the gas-liquid outlet 4324. The outlet 4332, located at the gas-liquid outlet 4324, allows for the introduction of more gaseous medium under the action of a high-speed gas-liquid mixture. The gas inlet 4331 of the gas chamber is connected to the gas phase outlet 14 of the reactor 1, the gas phase outlet 71 of the heat exchanger 7, and the gas phase outlet 82 of the reactor 8. The discharged gas phase medium is reintroduced into the reaction system through the gas chamber 433, which can improve the reaction conversion rate.

[0048] The gas-liquid inlet 4323 includes a gradually decreasing volume bell-shaped section 43231 and a cylindrical section 43232. The diameter of the generating column 431 is larger than the diameter of the cylindrical section 43232 but smaller than the maximum diameter of the bell-shaped section 43231. The structure of the gradually decreasing volume bell-shaped section 43231 and the cylindrical section 43232 increases the fluid inflow velocity and enhances the impact effect.

[0049] The gas-liquid outlet 4324 is a gradually expanding funnel-shaped opening, and the end of the generating column 431 has a truncated cone section 4316 with a gradually increasing diameter. The diameter of the truncated cone section 4316 is smaller than the diameter of the bubble cutting unit 4311. A channel is formed between the truncated cone section 4316 and the gas-liquid outlet 4324, and high-concentration micro-nano bubbles are discharged from the gas-liquid outlet 4324.

[0050] The number of bubble cutting units 4311 is no less than 3. In this embodiment, the generating column 431 has 10 bubble cutting units 4311 and 9 pressure-reducing grooves 4314. The pressure inside the generating column is measured. An existing pressure transmitter can be installed at the position to be measured in the generating column. The pressure transmitter is connected to a secondary instrument to read and record the value. The pressure at each location is shown in Table 1. When the gas-liquid mixed fluid enters the cylindrical section 43232 of the gas-liquid inlet 4323, the pressure is 0.4-1.0 MPa. The cross-sectional area at the impact platform 4315 and the pressure-reducing groove 4314 increases, and the pressure is reduced to generate micro-nano-scale bubbles. After 10 times of pressure reduction by increasing the cross-sectional area, the pressure is 0.14-0.3 MPa.

[0051] Table 1 Pressure values ​​at the location of increased cross-sectional area Higher pressure results in higher gas solubility. Reducing the pressure gradually releases the dissolved gas (forming bubbles), and the gas undergoes impact and collision to generate micro- and nano-sized bubbles. The bubble size and proportion can be controlled by increasing or decreasing the number of pressure reduction cycles.

[0052] The mass transfer effects of bubbles of different sizes were compared. The mass transfer effect was determined using the dissolved oxygen measurement method (dissolved oxygen can be detected using the electrode method). Water was used instead of liquid material, and air was used instead of gaseous material. The degree of gas-liquid mixing was determined by measuring the amount of oxygen dissolved in the water. The results are as follows: Figure 6 As shown, Stratified Flow, Translent Flow, and Mist Flow refer to laminar flow, transport flow, and mist flow, respectively, with a higher proportion of mist flow indicating better mass transfer. a, b, c, and d represent the mass transfer effects of large bubbles, medium bubbles, small bubbles, and micro / nano bubbles, respectively. Bubbles in c are generated using a Venturi ejector, and micro / nano bubbles in d are generated using the micro / nano bubble generator of this invention. The micro / nano bubble generator can reduce laminar flow and increase mist flow, improving mass transfer efficiency by more than 30%. Compared to ordinary bubbles generated by a Venturi ejector, the mass transfer effect of micro / nano bubbles can be improved by 4 times.

[0053] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system, characterized in that: The device includes a reaction vessel, a reactor, a heat exchanger, a large-scale nano-bubble generator, and a small-scale nano-bubble generator. The reaction vessel has a feed port and a gas-liquid inlet at the top and bottom, respectively. A gas phase outlet and a liquid phase product outlet are provided between the feed port and the gas-liquid inlet, with the gas phase outlet located above the liquid phase product outlet. The gas-liquid inlet of the reaction vessel is connected to the outlet of the large-scale nano-bubble reactor. The liquid phase product outlet of the reaction vessel is connected to the inlet of the heat exchanger and a collection valve. The outlet of the heat exchanger is connected to the inlet of the large-scale nano-bubble reactor. The outlet of the collection valve is connected to the inlet of the small-scale nano-bubble generator. The outlet of the small-scale nano-bubble generator is connected to the bottom of the reactor. A product outlet is provided in the upper middle part of the reactor and is connected to a product valve.

2. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 1, characterized in that: The gas-liquid inlet of the reactor is connected to the outlet of the first check valve, and the inlet of the first check valve is connected to the raw material inlet valve and the outlet of the large and micro nano bubble generator.

3. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 1, characterized in that: The gas phase outlet of the reactor is connected to the inlet of the second check valve, the top gas phase outlet of the heat exchanger is connected to the inlet of the third check valve, the top gas phase outlet of the reactor is connected to the fourth check valve, and the outlets of the second, third, and fourth check valves are respectively connected to the gas supply pipeline.

4. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 1, characterized in that: The large micro-nano bubble generator includes a circulation pump A, a micro-nano bubble generator A, and an air inlet pipe A. The small micro-nano bubble generator includes a circulation pump B, a micro-nano bubble generator B, and an air inlet pipe B. The air inlet pipe A and the air inlet pipe B are respectively connected to an air circuit valve, and the air circuit valve is connected to an air supply device.

5. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 4, characterized in that: Both the micro-nano bubble generator A and the micro-nano bubble generator B include a housing and a generating column installed inside the housing. The housing has a gas-liquid inlet and a gas-liquid outlet. The gas-liquid mixture entering from the gas-liquid inlet flows through the generating column and then flows out from the gas-liquid outlet. The generating column includes multiple bubble cutting units. The surface of the bubble cutting unit is provided with a flow channel, and there are pressure-reducing grooves between the bubble cutting units.

6. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 5, characterized in that: The flow channel is a spiral flow channel; the inflow end of the bubble cutting unit is provided with a serrated surface; the front end of the bubble cutting unit at the gas-liquid inlet end is provided with an impact platform.

7. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 5, characterized in that: The housing includes an outer shell and an inner shell. The generating column is disposed in the inner shell cavity. The inner shell has a gas-liquid inlet and a gas-liquid outlet at both ends, respectively. The outer shell cavity has a gas chamber. The gas inlet of the gas chamber is disposed on the outer shell, and the gas outlet of the gas chamber is connected to the inner shell cavity.

8. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 7, characterized in that: The air inlet of the gas chamber is located in the upper middle part of the outer shell, and the air outlet of the gas chamber is located at the gas-liquid outlet. The gas-liquid inlet includes a gradually decreasing volume funnel-shaped section and a cylindrical section. The diameter of the generating column is larger than the diameter of the cylindrical section but smaller than the maximum diameter of the funnel-shaped section. The gas-liquid outlet is a gradually expanding funnel-shaped section. The end of the generating column has a truncated cone section with a gradually increasing diameter. The diameter of the truncated cone section is smaller than the diameter of the bubble cutting unit.

9. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to claim 1, characterized in that: A feed valve is provided between the large and small nano bubble generator and the reactor.

10. A continuous gas-liquid two-phase or gas-liquid-solid three-phase reaction system according to any one of claims 1-9, characterized in that: The reaction vessel and reactor are respectively equipped with a supported catalyst, which is arranged vertically, horizontally or spirally inside the reaction vessel.

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