CN118925625B - A radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction - Google Patents

Abstract

The invention discloses a radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction. The reactor comprises a reactor, a plurality of annular micro-channel areas, a plurality of radial micro-channel walls, a plurality of dehydrogenation or oxygen evolution catalysts, an inlet, an outlet and a plurality of annular micro-channel walls, wherein the annular micro-channel areas are arranged in a cavity of the reactor to divide the cavity into a central area and a peripheral cavity, the annular micro-channel areas are uniformly divided into a plurality of identical radial micro-channels by the plurality of radial micro-channel walls, the radial micro-channels are not communicated with each other in the annular micro-channel areas and are gradually increased in cross section along the outward direction of the center of the cavity, the inlet is communicated with the central area of the cavity, the outlet is communicated with the peripheral cavity, and the bottom surface of the annular micro-channel areas is provided with the dehydrogenation or oxygen evolution catalysts. The reactor ensures that the distribution of fluid is more uniform, the conditions such as pressure loss and temperature reaction inside each micro-channel are kept consistent, and the design of increasing the cross section of the micro-channel can lead gas and liquid to be rapidly separated, thereby avoiding the problem of detention, being beneficial to the uniform transfer of heat from the center to the periphery and ensuring the controllability of the reaction.

Description

Radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction

Technical Field

The invention belongs to the technical field of microreactors, and particularly relates to a radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction.

Background

Microreactors are a device for carrying out chemical reactions under microscale, and gradually become research hotspots in the fields of chemical synthesis, biochemistry and the like due to the advantages of high efficiency, low cost, energy conservation, environmental protection and the like. Dehydrogenation or oxygen evolution reaction is an important gas-liquid multiphase chemical reaction and plays a key role in the fields of energy conversion, chemical synthesis, biomass utilization, new material preparation, environment-friendly chemistry and the like.

The design of micro-channels and micro-reactors has been an important point and hot spot in the micro-reactor technology field, and is a difficulty in applying the micro-reactor technology to practical processes. In particular, under the dehydrogenation or oxygen evolution reaction system, the micro-reactor has small scale and internal flow in a laminar flow state, the flow and mass transfer characteristics of the micro-reactor are greatly different from those of the conventional reactor, the acceleration of the discharge of gas is important to maintain the reaction and the reaction efficiency, and the means of changing the channel structure, externally applied force field, introducing surface coating and the like are often used for reducing the adhesion and resistance of bubbles so as to improve the discharge rate of the gas. The device does not depend on external power, only utilizes the channel structure design and the control of the fluid flow property, and has the characteristics of stability, simplicity, convenience, wide application range and the like.

In microreactor designs involving dehydrogenation or oxygen evolution reactions, the prior art suffers mainly from the following disadvantages:

(1) In the prior microreactor, a straight microchannel structure is often used as the structure of the reactor, but in the straight microchannel related to multiphase reaction, gas is easy to gather in the channel, the detention time is increased, detention is easy to occur, and gas and liquid cannot be separated in time, so that the reaction conversion rate is reduced.

(2) In order to achieve faster emulsification and rapid generation of micro-droplets while preserving the hydrodynamic and fluidic properties of the reaction stream within the microchannel, the throughput is generally increased by integrating multiple straight flow channels in parallel, which reduces the number of devices and saves space, but the main difficulty of parallel amplification is to maintain uniform distribution of the reaction fluid across the different channels, which is an important influencing factor for the break-up of the droplets within the multistage channels. Under the influence of pressure drop fluctuation, two-phase flow and other factors, the uneven distribution of the fluid in different channels can lead to uneven reaction conditions, thereby leading to uncontrollable reaction results.

(3) In order to improve the mass transfer and heat transfer rate in the reaction process, high integration and quick thermal response are realized, and the microreactor is often in a sealed integrated design, but the sealed integrated structure easily causes accumulation and blockage of bubbles in the microchannel, is not easy to discharge, influences the stability of the reaction process, and can cause uneven distribution of local hot spots and fluid, thereby reducing the overall heat and mass transfer performance. And the micro-channel with a complex structure is easy to have dead zone, deposit and scale after long-time use, and is difficult to clean and maintain, and the micro-channel is blocked when serious, so that the performance of equipment is obviously reduced.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction. The invention shortens the reaction time, reduces the retention of materials in the reactor and reduces the occurrence of side reactions by optimizing the geometry of the reactor, thereby improving the performance of the reactor and obtaining more target products (such as hydrogen and oxygen).

The technical scheme of the invention is as follows:

The invention provides a radial micro-reactor for liquid phase dehydrogenation or oxygen evolution reaction, which comprises a reactor chamber, wherein the reactor chamber is connected with an inlet and a plurality of outlets, a circle of annular micro-channel area is arranged in the chamber and divides the chamber into a central area and a peripheral chamber, a plurality of micro-channel walls are circumferentially arranged in the annular micro-channel area and uniformly divide the annular micro-channel area into a plurality of identical radial micro-channels, the radial micro-channels are not communicated with each other in the annular micro-channel area and are gradually increased in cross section along the central outward direction of the chamber, the inlet is communicated with the central area of the chamber, the outlets are communicated with the peripheral chamber, the width of the radial micro-channel is less than or equal to 3mm, the height of the chamber is less than or equal to 2mm, and a dehydrogenation or oxygen evolution catalyst is arranged on the bottom surface of the annular micro-channel area.

According to the preferred scheme of the invention, one or more circles of fins for preventing bubbles from flowing back are arranged around the inlet in the central area, wherein the diameter of a circle surrounded by the outermost circle of fins is 0-2mm larger than the diameter of the inlet, the distance between the adjacent fins in the same circle is not more than 0.5mm, the fins in the adjacent circles are arranged in a staggered mode, and the distance between the adjacent circles is not more than 0.5mm.

The invention also provides a dehydrogenation or oxygen evolution method based on the microreactor, which comprises the steps that liquid phase reaction raw materials enter the central area of the reactor chamber from an inlet, then the raw materials uniformly flow into each radial microchannel, in the radial microchannels, liquid phase reactants react on the surface of a catalyst to generate gas and form gas-liquid two-phase flow in the microchannels, generated bubbles can push the fluid to move outwards through the ascending dynamic action of the bubbles, the generation and the ascending of the bubbles enhance the mixing of the fluid, the contact efficiency of the reactants on the surface of the catalyst is improved, the cross section of the radial microchannels is gradually increased, the flow resistance in the product discharging process is reduced, the side reaction caused by product accumulation is prevented, and the obtained product and unreacted materials enter the peripheral chamber along the radial microchannels with the gradually increased cross section and are finally discharged through an outlet.

Compared with the prior art, the invention has the beneficial effects that:

(1) The radial micro-reactor provided by the invention has a structure with the middle gathered and the periphery dispersed, the middle gathered structure is favorable for diffusing gas to an outlet, is favorable for quickly separating gas from liquid, avoids the problem of detention, increases the contact area of reactants and a catalyst by virtue of the design of the radial micro-channels, is favorable for uniformly transferring heat from the center to the periphery, is favorable for controlling the reaction temperature, and can ensure that fluid is uniformly distributed among a plurality of reactor units, and the accumulation or shortage of the fluid in certain units is avoided. The uniformity improves the stability and consistency of the reaction, the scale of the reactor can be flexibly adjusted according to the actual demand by connecting a plurality of micro-reactor units in parallel, the total reaction area is increased and the contact between reactants is increased, so that the overall reaction rate and the conversion rate are improved, a plurality of micro-reactor units can be well integrated in parallel, and the performance of the reactor is improved.

(2) The radial reactor has the advantages that the distribution of fluid is more uniform, the problem of uneven distribution of fluid among different channels is avoided, meanwhile, the conditions such as pressure loss and temperature reaction in each channel are more uniform, the controllability of the reaction result is ensured, the flow change of two-phase flow in different channels can be balanced better, the non-uniformity of the reaction is reduced, and the parallel amplification is facilitated.

(3) The reactor adopts the design that the walls of each channel are closed, so that the gas-liquid flows in the channels of the reactor are not mutually influenced, the retention phenomenon is reduced, the risk of inter-phase reaction is reduced, the stability of the reaction is maintained, and the gas-liquid separation efficiency is obviously improved. In addition, the channels separated from each other enhance the reaction control capability, enable gas and liquid to flow in independent channels, facilitate precise adjustment of flow rate, pressure and temperature, and achieve consistency and repeatability of reaction conditions. In addition, in the aspect of reducing maintenance cost, the channel wall is not opened, so that the risks of fluid leakage and cross contamination are effectively reduced, the failure rate is reduced, the cleaning process is simplified, and the economy and stability of the equipment are improved. Finally, the design improves the safety, reduces the risk of inter-phase reaction, and ensures the safety of operators. These advantages make the invention have important application value and good market prospect in the field of microreactors.

(4) The channel wall of the invention can be further optimally designed according to the requirements (such as the channel wall can be processed with notched concave-convex points and the like, thereby increasing the contact area of reactants and the catalyst, forming more reaction sites, increasing the contact area of the reactants and the catalyst, being beneficial to mass transfer process, thereby improving the reaction conversion rate, embedding or coating the catalyst on the channel wall, and the like), and the designs can increase the contact area of the reactants and the catalyst, improve the mass transfer and heat transfer efficiency, and ensure that the reaction is carried out in the optimal temperature range.

Drawings

FIG. 1 is a schematic view of the whole radial microreactor in the example.

FIG. 2 is a schematic illustration of the placement of different exit locations of a radial microreactor.

FIG. 3 is a schematic diagram of a radial microreactor split.

Fig. 4 is a schematic diagram of a cover plate and microchannel wall arrangement.

Fig. 5 is a schematic of a linear stepped diverging microchannel wall as illustrated in the examples.

Fig. 6 is a schematic diagram of a sinusoidal microchannel wall as illustrated in the examples.

Fig. 7 is a schematic view of a microchannel wall structure with grooves and secondary microchannel walls as illustrated in the examples.

FIG. 8 is a schematic view of a finned microchannel through wall structure.

Fig. 9 is a schematic view of an arrangement of different fins.

FIG. 10 is a graph showing the conversion of 30wt% hydrogen peroxide in a radial microreactor and in a channel-free configuration.

FIG. 11 is a schematic diagram of 10wt% hydrogen peroxide conversion and reaction rate.

FIG. 12 is a schematic of 30wt% hydrogen peroxide sinusoidal radial microreactor conversion.

FIG. 13 is a graph showing the comparison of hydrogen production from a stirred tank reactor and a microchannel reactor.

FIG. 14 is a schematic of a parallel microchannel reactor for comparative experiments.

FIG. 15 is a schematic diagram of the test results of example 4.

In the figure, an inlet 1, a cover plate 2, a reactor bottom plate 3, mounting holes 4, an outlet 5, a pipeline interface device 6, a micro-channel wall 7, fins 8 and a sealing ring 9.

Detailed Description

The invention is further illustrated and described below in connection with specific embodiments. The described embodiments are merely exemplary of the present disclosure and do not limit the scope. The technical features of the embodiments of the invention can be combined correspondingly on the premise of no mutual conflict.

The invention provides a radial microreactor which is mainly used for dehydrogenation or oxygen evolution reaction of liquid phase reaction raw materials, and in the embodiment of the invention, hydrogen peroxide oxygen evolution and perhydrogenated dibenzyl toluene dehydrogenation are used as two typical liquid phase oxygen evolution and dehydrogenation reactions for experiments. However, the reactor of the present invention can be applied to dehydrogenation or oxygen evolution of any liquid phase reaction raw material. In the dehydrogenation or oxygen evolution reaction process of the liquid phase reaction raw material, generated hydrogen or oxygen can overflow from the liquid phase in the form of bubbles, the overflowed bubbles can prevent the flow of liquid phase materials and even flow guide, and on the other hand, the bubbles can raise the pressure in the reactor to generate certain potential safety hazards.

In order to solve the problems in the prior art, as shown in fig. 1-3, the radial micro-reactor for liquid phase dehydrogenation or oxygen evolution reaction comprises a reactor chamber, wherein the reactor chamber is connected with an inlet 1 and a plurality of outlets 5, a circle of annular micro-channel area is arranged in the chamber and divides the chamber into a central area and a peripheral chamber, a plurality of micro-channel walls 7 are circumferentially arranged in the annular micro-channel area, each micro-channel wall 7 is radially arranged, the annular micro-channel area is uniformly divided into a plurality of identical radial micro-channels by the plurality of micro-channel walls 7, the radial micro-channels are not communicated with each other in the annular micro-channel area and are gradually increased in the cross section area of each radial micro-channel along the center of the chamber outwards direction, the inlet 1 is communicated with the central area of the chamber, the plurality of outlets 5 are communicated with the peripheral chamber, the width of the radial micro-channel is less than or equal to 3mm, the height of the chamber is less than or equal to 2mm, and the bottom surface of the annular micro-channel area is provided with a dehydrogenation or oxygen catalyst.

As shown in fig. 1 to 3, in some embodiments of the present invention, the reactor includes a reactor bottom plate 3 and a cover plate 2 that can be fastened to each other, the reactor bottom plate 3 is internally provided with the reactor chamber, and the reactor chamber is sealed by the fastened cover plate 2. In some embodiments of the invention, fastening of the two is achieved by machining mechanical locating holes in the reactor bottom plate 3 and the cover plate 2 and by bolts. As shown in fig. 3, in order to connect the inlet 1 and the outlet 5 of the microreactor with external pipelines, in this embodiment, a pipeline interface device 6 is disposed on the inlet 1 and the outlet 5, the pipeline interface device 6 is composed of a pipeline, a compression ring and a compression plug, wherein the pipeline penetrates into the compression plug, the fixation of the pipeline and the compression plug is realized through the compression ring, and the compression plug is installed in the inlet 1 or the outlet 5 through threads. In fig. 3, a sealing ring groove is arranged at the top of the reactor chamber, and a sealing ring 9 is arranged in the sealing ring groove and used for realizing sealing when the reactor bottom plate 3 and the cover plate 2 are buckled.

As shown in fig. 2, the inlet 1 is arranged in the center of the cover plate 2, the outlet 5 can be arranged on the cover plate 2, or on the side wall or even the bottom surface of the bottom plate 3 of the reactor, and the outlets 5 are preferably uniformly arranged along the peripheral chamber. The diameter of the reactor inlet 1 is less than or equal to 4mm, and the horizontal distance between the inlet of each micro-channel and the edge of the reactor inlet 1 is equal to or less than 5mm.

In some embodiments of the invention, as shown in fig. 4-8, the microchannel walls are maintained at equal widths throughout the length of the microchannel to ensure uniform flow and heat transfer, and the microchannel walls may be linear in length (as illustrated in fig. 4, 5 and 7) or uniformly curved in length (as illustrated in fig. 6, sinusoidal in length), reducing flow separation and turbulence to reduce flow resistance and dead space and improve flow efficiency of the reactor. The uniform curved design allows for more complex flow paths to be achieved in a limited space, optimizing the shape and size of the reactor.

In some embodiments of the invention, the central region of the reactor chamber has a height that is less than the height of the annular microchannel region, with the reactor chamber height increasing gradually or stepwise in the radial direction within the annular microchannel region. The reactor chamber can be realized by machining an inverted cone structure on the lower surface of the cover plate, and the inverted cone structure can be a truncated cone, a cone or a stepped boss. The design of the reactor chamber can ensure that reactants are uniformly distributed in the chamber, avoid overhigh or overlow local concentration, promote the stability and the efficiency of the reaction, reduce the influence of dead zones, promote the overall efficiency of the reactor, and effectively slow down the fluid speed, promote the mixing and the contact of the reactants and improve the reaction efficiency. When the shape of the reactor chamber changes due to the design, the microchannel walls also need to be adjusted in shape to meet the purpose of separating adjacent microchannels, fig. 5 illustrates a 4-stage stepped-up microchannel wall with equal stage lengths and equal adjacent step increases to accommodate the reactor chamber with stepped increases in height.

In some embodiments of the invention, in order to increase the contact area of reactants with catalyst, more reaction sites are formed, dehydrogenation or oxygen evolution catalysts are further embedded or coated on the surface of the microchannel walls, or grooves or bumps are provided on the surface of the microchannel walls to increase the surface area, which designs are beneficial to mass transfer process and thus increase the reaction conversion, fig. 7 illustrates a microchannel wall with groove design.

As shown in fig. 4 and 7, when the cross section of the micro-channel is too large, a secondary micro-channel wall may be further disposed in each radial micro-channel, where the secondary micro-channel wall is disposed along the fluid flow direction to divide the downstream area of the radial micro-channel into a plurality of identical sub-divided micro-channels, and the starting point of the secondary micro-channel wall may be selected according to the cross section size or width of the radial micro-channel, for example, when the cross section size reaches a set value or the micro-channel width is greater than 3mm, the secondary micro-channel wall may be disposed, and the end point is the outlet of the radial micro-channel.

As shown in figures 8 and 9, in order to prevent the backflow of fluid, one or more circles of fins for preventing bubbles from flowing back are arranged around the inlet in the central area, wherein the diameter of a circle surrounded by the outermost circle of fins is 0-2mm larger than the diameter of the inlet, the distance between the adjacent circles of fins is not more than 0.5mm, the fins of the adjacent circles are arranged in a staggered mode, and the distance between the adjacent circles is not more than 0.5mm. Fig. 9 shows two forms of cylindrical fins and triangular fins, and the staggered arrangement is adopted, so that the back flow of bubbles can be well prevented.

The invention is further described below in connection with specific examples. The flow of the reaction performed by the microreactor can be described as that liquid phase reaction raw materials enter a central area of a reactor chamber from an inlet, then the raw materials uniformly flow into radial microchannels, in the radial microchannels, liquid phase reactants react on the surface of a catalyst to generate gas and form gas-liquid two-phase flow in the microchannels, generated bubbles can push fluid to move outwards under the action of the ascending power of the bubbles, the generation and the ascending of the bubbles enhance the mixing of the fluid, the contact efficiency of the reactants on the surface of the catalyst is improved, the cross section of the radial microchannels is gradually increased, the flow resistance in the product discharging process is reduced, the side reaction caused by product accumulation is prevented, and the obtained product and unreacted materials enter the peripheral chamber along the radial microchannels with the gradually increased cross section and are finally discharged through an outlet.

1. Taking a hydrogen peroxide decomposition experiment as an example

Example 1 experiments were carried out in a radial microreactor with a cavity volume of 62mm x 2mm as shown in fig. 1, the bottom surface of the cavity of which was laid with a catalyst Pt layer, the annular microchannel zone comprising 20 radially arranged linear microchannel walls of 18.5mm x 1mm, in addition, two linear secondary microchannel walls were arranged between every two linear microchannel walls, the total number of secondary microchannel walls of the annular microchannel zone was 20, the size was 12mm x 1mm, the tail ends of the linear microchannel walls and the secondary microchannel walls were all located on the same circumference, the entrance width of each radial microchannel was 1mm, the largest channel size was 3mm, and the starting point of the secondary microchannel wall was laid at 3mm channel width. The inlet and the outlet are connected with an M6 compression ring switching hard pipe (the outer diameter is 3.2mm multiplied by the inner diameter is 1.6 mm), and 3mm is reserved between the inlet position of the micro-channel and the inlet edge of the cavity. At the same time, a comparative experiment was performed in a rectangular cavity of the same size without the microchannel structure.

The hydrogen peroxide solution with the concentration of 30wt percent is introduced from the inlet at different flow rates, the gas-liquid mixture flows out from the outlet, the conversion rate in the reactor provided with the radial micro-channels can reach 92.2% at the highest, and the reaction conversion rate exceeds 50% at a low inlet flow rate (7 ml/h). As shown in fig. 10, it can be seen from fig. 10 that compared with the comparative experiment without the microchannel structure, the conversion rate of hydrogen peroxide is greatly improved by arranging the radial microchannels.

Example 2 by using the radial microreactor of example 1, 10wt% hydrogen peroxide solution was introduced from the inlet at different flow rates, the gas-liquid mixture was flowed out from the outlet, the conversion rate was up to 87%, and the experimental results were shown in fig. 11. As can be seen from fig. 11, the microreactor has a concentration conversion of 10wt% higher than that of 30wt% in the microchannel-free structure in the example, enabling low concentration hydrogen peroxide conversion.

Example 3 experiments were carried out in a microreactor having a cavity volume of 62mm x 2mm, the bottom surface of the cavity of which was laid with a catalyst Pt layer, the microchannel walls were changed to the microchannel structure shown in fig. 7, i.e., the microchannel walls were of sinusoidal structure in the length direction, the wave-form fluctuation direction was the wave-form of the microchannel in the width direction, i.e., y=sin (x) driving, the wave-form length was 25mm (6-8 pi), and the entrance width of the channels was 1mm for a total of 20 channel walls (wall width 1mm, height 1 mm). The hydrogen peroxide solution with 30wt% is introduced from the inlet at different flow rates, and the gas-liquid mixture flows out from the outlet, and the result is shown in fig. 12, and as can be seen from fig. 12, the conversion rate of the reaction can be improved by the microchannel walls with sine structures. Both the rectilinear microchannel walls of examples 1 and 2, and the sinusoidal configuration of example 3, reduce flow separation and turbulence and thus reduce drag and dead space, improving the flow efficiency of the reactor. The sinusoidal design of example 3 also allows for more complex flow paths to be achieved in a limited space, optimizing the shape and size of the reactor.

2. With the radial microreactor structure of example 1, an inlet/outlet port was connected to an M6 pressure ring-connected hard tube (outer diameter 3.2 mm. Times.inner diameter 1.6 mm), 2 wt% Pt/Al ₂O₃ catalyst was coated on the bottom of the reactor, and the perhydrogenated dibenzyl toluene was introduced from the inlet port at an inlet flow rate of 10ml/h, and an experiment was conducted on the dehydrogenation of the perhydrogenated dibenzyl toluene. Meanwhile, the dehydrogenation experiment of the perhydrogenated dibenzyl toluene is carried out in a cylindrical stirred tank reactor with the volume of pi× (70/2 mm) ² X10 mm, and 2 wt percent Pt/Al ₂O₃ is taken as a catalyst. The experimental temperature is 290 ℃, the working pressure is 1Mpa, and the reactor materials are stainless steel.

The change in reactant concentration was calculated from the number of moles of hydrogen gas generated during the reaction. The hydrogen yield was calculated using the following formula hydrogen yield = maximum hydrogen yield per theoretical hydrogen yield in practical experiments x 100%.

As shown in fig. 13, it can be seen from fig. 13 that the radial microreactor of the present invention can significantly improve the dehydrogenation yield of perhydrogenated dibenzyl toluene compared to the stirred tank reactor.

Example 4 set up of a microchannel experimental group a, a fin-added microchannel experimental group B and a comparative group, wherein experiments of experimental group a and experimental group B were performed in a radial microreactor with a cavity volume of 62mm x 2mm shown in fig. 1,2 wt% of Pt/Al ₂O₃ catalyst was coated on the bottom of the reactor, an annular microchannel zone comprising 20 linear microchannel walls of 18.5mm x 1mm, and further, a linear secondary microchannel wall was provided between every two linear microchannel walls, the total of the secondary microchannel walls of the entire annular microchannel zone being 20, and the size was 12mm x 1mm. Compared with the experimental group A, the experimental group B is only different in that fins for preventing bubbles from flowing back are arranged, specifically, a circle of 20 circular needle posts (with the diameter of 0.6mm and uniformly distributed according to the circumference) are arranged at a position 1mm away from the inlet edge of a micro-channel, the vertical distance between the center of each needle post and the center axis of the channel wall is 0.9mm, the inlet width of the micro-channel is 1mm, the maximum channel size is 3mm, the inlet and the outlet are connected with M6 compression ring switching hard pipes (with the outer diameter of 3.2mm multiplied by the inner diameter of 1.6 mm), and 3mm is reserved between the inlet position of the micro-channel and the inlet edge of a cavity. The comparative group was subjected to comparative experiments in a parallel microchannel reactor chamber as shown in fig. 14, the parallel microchannels had an inlet-outlet pitch of 50mm, 26 parallel microchannels in total, and the walls of the parallel microchannels were 45mm long, 1mm wide and 1mm in channel pitch.

The full hydrogenated dibenzyl toluene is introduced from an inlet at different inlet flow rates, the experimental temperature is 290 ℃, the working pressure is 1Mpa, and the reactor material is stainless steel. The experimental results are shown in the following figure 15, compared with the parallel microchannel employed in the invention, the conversion rate of the radial microreactor with the pin is obviously higher than that of the parallel microchannel reactor, and the radial microchannel with the pin can further improve about 10% of conversion rate under the condition of high inlet flow, and the main reason is that the design of the pin fin further prevents the back flow of bubbles, so that the material can flow more smoothly.

The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit of the invention.

Claims (8)

1. A liquid phase dehydrogenation or oxygen evolution method based on a radial microreactor, characterized in that the radial microreactor comprises a reactor chamber, the reactor chamber is connected with an inlet and a plurality of outlets, characterized in that a circle of annular microchannel area is arranged in the chamber, the annular microchannel area divides the chamber into a central area and a peripheral chamber; a plurality of microchannel walls are arranged in the annular microchannel area, the microchannel walls are arranged radially, and the plurality of microchannel walls evenly divide the annular microchannel area into a plurality of completely identical radial microchannels; the radial microchannels are not interconnected in the annular microchannel area, and the cross-sectional area of the radial microchannels increases gradually from the center of the chamber to the outside; the inlet is connected to the central area of the chamber, and the plurality of outlets are connected to the peripheral chamber; the width of the radial microchannel is ≤3mm, and the height of the chamber is ≤2mm; a dehydrogenation or oxygen evolution catalyst is arranged on the bottom surface of the annular microchannel area; The height of the central area of the reactor chamber is lower than that of the annular microchannel area, and the height of the reactor chamber gradually increases or increases in steps along the radial direction in the annular microchannel area; The liquid phase dehydrogenation or oxygen evolution method comprises the following steps: liquid phase reaction raw materials enter the central area of the reactor chamber from an inlet, and then the liquid phase reaction raw materials flow evenly into each radial microchannel; in the radial microchannel, the liquid phase reactants react on the catalyst surface to generate gas and form a gas-liquid two-phase flow in the microchannel; the generated bubbles can push the fluid to move outward through the dynamic effect of the rising bubbles; the generation and rising of the bubbles enhance the mixing of the fluid and improve the contact efficiency of the reactants on the catalyst surface; the cross-section of the radial microchannel gradually increases, reducing the flow resistance in the process of product discharge, preventing side reactions caused by product accumulation, and the obtained products and unreacted materials enter the peripheral chamber along the radial microchannel with gradually increasing cross-section, and are finally discharged through the outlet. 2. The liquid-phase dehydrogenation or oxygen evolution method based on a radial microreactor according to claim 1 is characterized in that the radial microreactor comprises a reactor bottom plate and a cover plate that can be interlocked, the reactor bottom plate is processed with the reactor chamber, and the cover plate is engaged with the reactor bottom plate to seal the reactor chamber; the inlet is arranged on the cover plate, and the outlet is arranged on the cover plate or the reactor bottom plate; the outlets are evenly arranged along the peripheral chamber. 3. The liquid-phase dehydrogenation or oxygen evolution method based on a radial microreactor according to claim 2 is characterized in that a sealing ring groove is arranged around the top of the reactor chamber, and a sealing ring is arranged in the sealing ring groove to achieve sealing when the reactor bottom plate and the cover plate are buckled together. 4. The liquid-phase dehydrogenation or oxygen evolution method based on a radial microreactor according to claim 1 is characterized in that the width of the microchannel wall remains equal over the entire length of the microchannel; the microchannel wall is designed to be straight or uniformly curved along the length direction; the horizontal distance between the inlet of each microchannel and the edge of the reactor inlet is ≤5mm; and the diameter of the reactor inlet is ≤4mm. 5. The liquid phase dehydrogenation or oxygen evolution method based on a radial microreactor according to claim 1, characterized in that a dehydrogenation or oxygen evolution catalyst is embedded or coated on the surface of the microchannel wall. 6. The liquid phase dehydrogenation or oxygen evolution method based on a radial microreactor according to claim 1, characterized in that the surface of the microchannel wall is provided with grooves or convex points to increase the surface area. 7. The liquid-phase dehydrogenation or oxygen evolution method based on a radial microreactor according to claim 1 is characterized in that a secondary microchannel wall is arranged in each radial microchannel, and the secondary microchannel wall is arranged along the fluid flow direction and divides the downstream area of the radial microchannel into a plurality of identical subdivided microchannels; the starting point of the secondary microchannel wall is selected according to the cross-sectional size of the radial microchannel, and the end point is the outlet of the radial microchannel. 8. The liquid-phase dehydrogenation or oxygen evolution method based on a radial microreactor according to claim 1 is characterized in that, in the central area, one or more circles of fins are arranged around the inlet to prevent bubble backflow, wherein the diameter of the circle surrounded by the outermost circle of fins is 0-2 mm larger than the inlet diameter, and the distance between adjacent fins in the same circle does not exceed 0.5 mm; the fins of adjacent circles are staggered, and the distance between two adjacent circles does not exceed 0.5 mm.