A radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction

Abstract

The present invention discloses a radial microreactor for liquid-phase dehydrogenation or oxygen evolution reaction. A ring-shaped microchannel area is arranged in the chamber of the reactor to divide the chamber into a central area and a peripheral chamber; a plurality of radial microchannel walls are arranged in the ring-shaped microchannel area to evenly divide the ring-shaped microchannel area into a plurality of completely identical radial microchannels; each radial microchannel is not connected to each other in the ring-shaped microchannel area, and the cross-sectional area of ​​each radial microchannel gradually increases from the center of the chamber to the outside; the inlet is connected to the central area of ​​the chamber, and the outlet is connected to the peripheral chamber, and a dehydrogenation or oxygen evolution catalyst is arranged on the bottom surface of the ring-shaped microchannel area. The reactor makes the distribution of the fluid more uniform, and the pressure loss, temperature reaction and other conditions inside each microchannel remain consistent, and the design of gradually increasing the cross-section of the microchannel can make the gas and liquid separate quickly, avoid the problem of retention, and facilitate the uniform transfer of heat from the center to the surroundings, thereby ensuring the controllability of the reaction.

Description

Technical Field

[0001] The invention belongs to the technical field of microreactors, and in particular relates to a radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction. Background Art

[0002] Microreactors are devices that carry out chemical reactions at a microscale. Due to their advantages of high efficiency, low cost, energy saving and environmental protection, they have gradually become a research hotspot in the fields of chemical synthesis and biochemistry. Dehydrogenation or oxygen evolution reaction is an important gas-liquid multiphase chemical reaction, playing a key role in energy conversion, chemical synthesis, biomass utilization, new material preparation and environmentally friendly chemistry.

[0003] The design of microchannels and microreactors has always been a focus and hotspot in the field of microreactor technology, and it is also a difficulty in the application of microreactor technology in practice. Especially in the dehydrogenation or oxygen evolution reaction system, the scale of the microreactor is small, and the internal flow is mostly in a laminar state. Its flow and mass transfer characteristics are very different from those of conventional reactors. Accelerating the discharge of gas is crucial to maintaining the reaction and maintaining the reaction efficiency. Changing the channel structure, applying an external force field, introducing surface coatings, etc. are often used to reduce the adhesion and resistance of bubbles to increase the gas discharge rate. It does not rely on external power, but only uses channel structure design and control of fluid flow properties. It has the characteristics of stability, simplicity, and a wide range of applications.

[0004] In the design of microreactors involving dehydrogenation or oxygen evolution reactions, the existing technology mainly has the following deficiencies:

[0005] (1) In current microreactors, straight microchannel structures are often used as the reactor structure. However, in straight microchannels involving multiphase reactions, gas tends to accumulate in the channel, increasing the residence time and easily causing retention. Gas and liquid cannot be separated in time, thereby reducing the reaction conversion rate.

[0006] (2) In order to achieve faster emulsification and rapid generation of tiny droplets while retaining the fluid mechanics and fluid properties of the reaction flow in the microchannel, the processing capacity is generally expanded by integrating multiple parallel straight channels in parallel. This method reduces the number of equipment and saves space, but the main difficulty in parallel amplification is to maintain the uniform distribution of the reaction fluid in different channels, which is an important factor affecting the rupture of droplets in multi-stage channels. Under the influence of many factors such as pressure drop fluctuations and two-phase flow rates, the uneven distribution of fluids in different channels leads to uneven reaction conditions, resulting in uncontrollable reaction results.

[0007] (3) In order to improve the mass transfer and heat transfer rates during the reaction process and achieve high integration and rapid thermal response, microreactors are often sealed and integrated. However, the closed integrated structure easily causes bubbles to accumulate and clog inside the microchannel, making it difficult to discharge, affecting the stability of the reaction process and possibly causing local hot spots and uneven fluid distribution, thereby reducing the overall heat and mass transfer performance. In addition, microchannels with complex structures are prone to dead zones, which are prone to deposition and scaling after long-term use, making them difficult to clean and maintain. In severe cases, microchannel blockage can significantly reduce the performance of the equipment. Summary of the invention

[0008] In order to solve the problems in the prior art, the present invention proposes a radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction. The present invention improves the reactor performance and obtains more target products (such as hydrogen and oxygen) by optimizing the reactor geometry to shorten the reaction time, reduce the retention of materials in the reactor, and reduce the occurrence of side reactions.

[0009] The technical solution of the present invention is as follows:

[0010] The invention provides a radial microreactor for liquid phase dehydrogenation or oxygen evolution reaction, comprising a reactor chamber, wherein the reactor chamber is connected with an inlet and a plurality of outlets, wherein a ring-shaped microchannel area is arranged in the chamber, wherein the ring-shaped microchannel area divides the chamber into a central area and a peripheral chamber; wherein a plurality of microchannel walls are arranged in the circumferential direction in the ring-shaped microchannel area, wherein the plurality of microchannel walls evenly divide the ring-shaped microchannel area into a plurality of completely identical radial microchannels; wherein the radial microchannels are not interconnected in the ring-shaped microchannel area, and the cross-sectional area of ​​the radial microchannels increases gradually from the center of the chamber to the outside; wherein the inlet is connected with the central area of ​​the chamber, and the plurality of outlets are connected with the peripheral chamber; wherein the width of the radial microchannel is ≤3 mm, and the height of the chamber is ≤2 mm; and a dehydrogenation or oxygen evolution catalyst is arranged on the bottom surface of the ring-shaped microchannel area.

[0011] According to a preferred embodiment of the present invention, 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 0-2mm larger than the inlet diameter, and the distance between adjacent fins in the same circle does not exceed 0.5mm; the fins of adjacent circles are staggered, and the distance between two adjacent circles does not exceed 0.5mm.

[0012] The present invention also provides a dehydrogenation or oxygen evolution method based on the microreactor, which comprises: liquid-phase reaction raw materials enter the central area of ​​the reactor chamber from an inlet, and then the 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, and the generated bubbles can push the fluid to move outward through the dynamic effect of the rising bubbles; the generation and rise 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 during the product discharge process, preventing side reactions caused by product accumulation, and the obtained products and unreacted materials enter the peripheral chamber along the radial microchannels with gradually increasing cross-sections, and are finally discharged through the outlet.

[0013] Compared with the prior art, the beneficial effects of the present invention include:

[0014] (1) The radial microreactor provided by the present invention has a structure that gathers in the middle and diverges around. The structure that gathers in the middle is conducive to the diffusion of gas to the outlet, helps the rapid separation of gas and liquid, and avoids the problem of retention; the design of the radial microchannel increases the contact area between the reactant and the catalyst, and is conducive to the uniform transfer of heat from the center to the surroundings, which helps to control the reaction temperature; the radial microchannel structure can ensure that the fluid is evenly distributed among multiple reactor units, avoiding the accumulation or shortage of fluid in some units. This uniformity improves the stability and consistency of the reaction. By connecting multiple microreactor units in parallel, the scale of the reactor can be flexibly adjusted according to actual needs, increasing the overall reaction area and the contact of the reactants, thereby improving the overall reaction rate and conversion rate, so that multiple microreactor units can be well integrated in parallel, and the reactor performance is improved.

[0015] (2) The structure of the radial reactor can make the fluid distribution more uniform, avoiding the problem of uneven fluid distribution between different channels. At the same time, the pressure loss, temperature reaction and other conditions inside each channel are more consistent, thereby ensuring the controllability of the reaction results. It can better balance the flow changes of the two-phase flow in different channels, reduce the unevenness of the reaction, and thus facilitate parallel amplification.

[0016] (3) The reactor of the present invention adopts a design in which each channel wall is closed, which makes the gas-liquid flow in each channel not affect each other, reduces the retention phenomenon, reduces the risk of interphase reaction, helps to maintain the stability of the reaction, and thus significantly improves the gas-liquid separation efficiency. In addition, the channels separated from each other enhance the reaction control ability, allowing gas and liquid to flow in independent channels, facilitating precise adjustment of flow rate, pressure and temperature, and achieving consistency and repeatability of reaction conditions. In addition, the design can also reduce maintenance costs. The non-opening of the channel wall effectively reduces the risk of fluid leakage and cross-contamination, reduces the failure rate, simplifies the cleaning process, and improves the economy and stability of the equipment. Finally, the design improves safety, reduces the risk of interphase reaction, and ensures the safety of operators. These advantages make the present invention have important application value and good market prospects in the field of microreactors.

[0017] (4) The channel wall of the present invention can be further optimized and designed as needed (for example, the channel wall can be treated with grooves, recesses, and convex points to increase the contact area between the reactants and the catalyst, form more reaction sites, increase the contact area between the reactants and the catalyst, and facilitate the mass transfer process, thereby improving the reaction conversion rate; the catalyst can be embedded or coated on the channel wall, etc.). These designs can increase the contact area between the reactants and the catalyst, improve the mass transfer and heat transfer efficiency, and ensure that the reaction is carried out within the optimal temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the overall radial microreactor in the embodiment.

[0019] Figure 2 Schematic diagram of the arrangement of different outlet positions of radial microreactor.

[0020] Figure 3 Schematic diagram of the decomposition of radial microreactor.

[0021] Figure 4 Schematic diagram of the cover plate and microchannel wall arrangement.

[0022] Figure 5 Schematic diagram of a linear stepped gradually expanding microchannel wall illustrated in an embodiment.

[0023] Figure 6 Schematic diagram of the sinusoidal microchannel wall shown in the embodiment.

[0024] Figure 7 Schematic diagram of the microchannel wall structure with grooves and secondary microchannel walls shown in the embodiments.

[0025] Figure 8 Schematic diagram of the microchannel wall structure with fins.

[0026] Fig. 9 Schematic diagram of the arrangement of different fins.

[0027] Fig.10 Schematic diagram of the conversion rate of 30wt% hydrogen peroxide in a radial microreactor and in a channel-free structure.

[0028] Fig.11 Schematic diagram of 10wt% hydrogen peroxide conversion rate and reaction rate.

[0029] Fig.12 Schematic diagram of the conversion rate of a 30wt% hydrogen peroxide sinusoidal radial microreactor.

[0030] Fig.13 This is a comparison chart of the hydrogen production effects of stirred tank reactor and microchannel reactor.

[0031] Fig.14 Schematic diagram of the parallel microfluidic reactor used for comparative experiments.

[0032] Fig.15 This is a schematic diagram of the test results of Example 4.

[0033] In the figure, there are an inlet 1, a cover plate 2, a reactor bottom plate 3, a mounting hole 4, an outlet 5, a pipeline interface device 6, a microchannel wall 7, a fin 8, and a sealing ring 9. DETAILED DESCRIPTION

[0034] The present invention is further described and illustrated below in conjunction with specific embodiments. The embodiments are merely exemplary of the present disclosure and do not define the scope of limitation. The technical features of each embodiment of the present invention may be combined accordingly without conflicting with each other.

[0035] The present invention provides a radial microreactor, which is mainly used for the dehydrogenation or oxygen evolution reaction of liquid phase reaction raw materials. In the embodiments of the present invention, hydrogen peroxide oxygen evolution and fully hydrogenated dibenzyltoluene dehydrogenation are used as two typical liquid phase oxygen evolution and dehydrogenation reactions for testing. However, it should be noted that the reactor of the present invention can be applied to the dehydrogenation or oxygen evolution reaction of any liquid phase reaction raw materials. During the dehydrogenation or oxygen evolution reaction of the liquid phase reaction raw materials described in the present invention, the generated hydrogen or oxygen will overflow from the liquid phase in the form of bubbles. On the one hand, the overflowing bubbles may prevent the flow of the liquid phase material or even divert the flow. On the other hand, the bubbles will increase the pressure in the reactor and produce certain safety hazards. In the existing reactors, the product yield is usually not high, and the reaction is difficult to control and difficult to scale up.

[0036] In order to solve the problems of the prior art, such as Figure 1-3As shown, the radial microreactor for liquid-phase dehydrogenation or oxygen evolution reaction provided by the present invention comprises a reactor chamber, the reactor chamber is connected with an inlet 1 and a plurality of outlets 5, a ring-shaped microchannel area is arranged in the chamber, and the ring-shaped microchannel area divides the chamber into a central area and a peripheral chamber; a plurality of microchannel walls 7 are arranged circumferentially in the annular microchannel area, each microchannel wall 7 itself is arranged radially, and the plurality of microchannel walls 7 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 ​​each radial microchannel increases gradually from the center of the chamber to the outside; the inlet 1 is connected to the central area of ​​the chamber, and the plurality of outlets 5 are connected to the peripheral chamber; the width of the radial microchannel is ≤3 mm, and the height of the chamber is ≤2 mm; a dehydrogenation or oxygen evolution catalyst is arranged on the bottom surface of the ring-shaped microchannel area.

[0037] like Figures 1 to 3 As shown, in some embodiments of the present invention, the reactor includes a reactor bottom plate 3 and a cover plate 2 that can be interlocked, the reactor chamber is processed in the reactor bottom plate 3, and the reactor chamber is sealed by interlocking the cover plate 2. In some embodiments of the present invention, mechanical positioning holes are processed on the reactor bottom plate 3 and the cover plate 2 and the two are fastened by bolts. Figure 3 As shown, in order to connect the inlet 1 and outlet 5 of the microreactor with external pipelines, a pipeline interface device 6 is provided on the inlet 1 and outlet 5 in this embodiment. The pipeline interface device 6 is composed of a pipeline, a pressure ring and a pressure plug. The pipeline passes through the pressure plug, and the pipeline and the pressure plug are fixed by the pressure ring. Then the pressure plug is installed in the inlet 1 or outlet 5 through threads. Figure 3 In the embodiment, a sealing ring groove is arranged around the top of the reactor chamber, and a sealing ring 9 is arranged in the sealing ring groove to achieve sealing when the reactor bottom plate 3 and the cover plate 2 are buckled together.

[0038] like Figure 2 As shown, the inlet 1 is arranged at the center of the cover plate 2, and the outlet 5 can be arranged on the cover plate 2, or on the side wall or even the bottom surface of the reactor bottom plate 3; the outlets 5 are preferably evenly arranged along the peripheral chamber. The diameter of the reactor inlet 1 is ≤4 mm; the horizontal distance between the inlet of each microchannel and the edge of the reactor inlet 1 is equal and ≤5 mm.

[0039] like Figure 4-Figure 8 As shown, in some embodiments of the present invention, the width of the microchannel wall remains equal over the entire length of the microchannel to ensure uniform flow and heat transfer of the fluid; the microchannel wall can be designed to be straight along the length direction (such as Figure 4 , Figure 5 and Figure 7 The microchannel walls are shown as straight lines) or uniformly curved ( Figure 6The microchannel wall shown is sinusoidal along the length direction), reducing flow separation and turbulence to reduce flow, thereby reducing resistance and dead zone, and improving the flow efficiency of the reactor. The uniformly curved design allows for more complex flow paths in a limited space, optimizing the shape and size of the reactor.

[0040] In some embodiments of the present invention, the height of the central area of ​​the reactor chamber is lower than the height of the annular microchannel area, and the height of the reactor chamber gradually increases or increases in a step-like manner along the radial direction in the annular microchannel area. This reactor chamber can be realized by processing 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. This reactor chamber design can ensure that the reactants are evenly distributed in the chamber, avoid local concentrations that are too high or too low, and promote the stability and efficiency of the reaction; reduce the impact of dead zones and improve the overall efficiency of the reactor; the gradual expansion design of the reactor chamber (cover plate) can effectively slow down the fluid velocity, and promote the mixing and contact of reactants, thereby improving the reaction efficiency. When the shape of the reactor chamber changes due to the design change, the microchannel wall also needs to be adjusted in shape to meet the purpose of separating adjacent microchannels. Figure 5 A four-step gradually expanding microchannel wall is illustrated, where each step has the same length and adjacent steps have the same increased height to accommodate a reactor chamber with a step-like increasing height.

[0041] In some embodiments of the present invention, in order to increase the contact area between the reactants and the catalyst and form more reaction sites, a dehydrogenation or oxygen evolution catalyst is further embedded or coated on the surface of the microchannel wall; or grooves or convex points are provided on the surface of the microchannel wall to increase the surface area. These designs are beneficial to the mass transfer process, thereby improving the reaction conversion rate; Figure 7 Schematic diagram of a microchannel wall with a groove design.

[0042] like Figure 4 and Figure 7 As shown, when the microchannel cross-section is too large, a secondary microchannel wall can be further arranged in each radial microchannel, and the secondary microchannel wall is arranged along the fluid flow direction to divide the downstream area of ​​the radial microchannel into multiple identical subdivided microchannels; the starting point of the secondary microchannel wall can be selected according to the cross-sectional size or width of the radial microchannel, for example, when the cross-sectional size reaches a set value or the microchannel width is greater than 3mm, the secondary microchannel wall can be arranged, and the end point is the outlet of the radial microchannel.

[0043] like Figure 8 and Fig. 9As shown, in order to prevent the backflow of fluid, the present invention further provides one or more circles of fins for preventing the backflow of bubbles around the inlet in the central area, wherein the diameter of the circle surrounded by the outermost circle of fins is 0-2mm larger than the diameter of the inlet, and the distance between adjacent fins in the same circle does not exceed 0.5mm; the fins of adjacent circles are staggered, and the distance between two adjacent circles does not exceed 0.5mm. Fig. 9 The diagram shows two types of fins: cylindrical fins and triangular fins. The staggered arrangement can effectively prevent bubble backflow.

[0044] The present invention is further described below in conjunction with specific embodiments. Among them, the process of using the microreactor of the present invention for reaction can be described as follows: the liquid phase reaction raw material enters the central area of ​​the reactor chamber from the inlet, and then the raw material flows evenly into each radial microchannel, in the radial microchannel, the liquid phase reactant reacts on the catalyst surface to generate gas and forms a gas-liquid two-phase flow in the microchannel, and the generated bubbles can push the fluid to move outward through the dynamic effect of the rising bubbles; the generation and rise of 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 during the product discharge process, preventing the side reaction caused by the accumulation of products, and the obtained products and unreacted materials enter the peripheral chamber along the radial microchannel with a gradually increasing cross-section, and are finally discharged through the outlet.

[0045] 1. Take the hydrogen peroxide decomposition experiment as an example

[0046] Example 1: Experimental Figure 1 The experiment was carried out in a radial microreactor with a cavity volume of 62mm×62mm×2mm, and a catalyst Pt layer was laid on the bottom of the cavity of the reactor; the annular microchannel area includes 20 18.5mm×1mm×1mm straight microchannel walls arranged radially, and in addition, a straight secondary microchannel wall is arranged between each pair of straight microchannel walls, and there are 20 secondary microchannel walls in the entire annular microchannel area, with a size of 12mm×1mm×1mm; the tail ends of the straight microchannel wall and the secondary microchannel wall are located on the same circumference, the inlet width of each radial microchannel is 1 mm, the maximum channel size is 3 mm, and the starting point of the secondary microchannel wall is arranged at a channel width of 3 mm. The inlet and outlet are connected to M6 pressure ring adapter hard pipes (outer diameter 3.2mm×inner diameter 1.6mm), and 3mm is reserved between the inlet position of the microchannel and the edge of the chamber inlet. At the same time, a comparative experiment was carried out in a rectangular cavity of the same size without a microchannel structure.

[0047] A 30wt% hydrogen peroxide solution was introduced from the inlet at different flow rates, and the gas-liquid mixture flowed out from the outlet. The conversion rate in the reactor with radial microchannels was as high as 92.2%, and at a low inlet flow rate (7ml / h), the reaction conversion rate exceeded 50%. The results are shown in Fig.10As shown, from Fig.10 It can be seen that, compared with the comparative experiment without microchannel structure, the present invention greatly improves the conversion rate of hydrogen peroxide by setting radial microchannels.

[0048] Example 2: Using the radial microreactor of Example 1, a 10 wt% hydrogen peroxide solution was introduced from the inlet at different flow rates, and the gas-liquid mixture flowed out from the outlet. The conversion rate can reach up to 87%. The experimental results are shown in FIG. Fig.11 As shown. Fig.11 It can be seen that the conversion rate of the microreactor at a concentration of 10wt% is higher than the conversion rate of 30wt% in the structure without microchannels in the example, and the conversion rate of low-concentration hydrogen peroxide can be achieved.

[0049] Example 3: The experiment was carried out in a microreactor with a cavity volume of 62 mm×62 mm×2 mm. The bottom surface of the cavity of the reactor was paved with a catalyst Pt layer; the microchannel wall was changed to Figure 7 The microchannel structure shown in the figure is that the microchannel wall is a sinusoidal structure along the length direction, and the waveform fluctuation direction is the width direction of the microchannel, that is, the waveform driven by y=sin(x), the band length is 25mm (6-8pi), a total of 20 channel walls (wall width 1mm, height 1mm) and the channel inlet width is 1mm. 30wt% hydrogen peroxide solution is introduced from the inlet at different flow rates, and the gas-liquid mixture flows out from the outlet. The results are shown in Fig.12 As shown, from Fig.12 It can be seen that the sinusoidal microchannel wall can also improve the conversion rate of the reaction. The straight microchannel walls of Examples 1 and 2 and the sinusoidal microchannel wall of Example 3 can reduce flow separation and turbulence, thereby reducing resistance and dead zone, and improving the flow efficiency of the reactor. The sinusoidal curved design of Example 3 also allows a more complex flow path to be realized in a limited space, optimizing the shape and size of the reactor.

[0050] 2. The radial microreactor structure of Example 1 was used, and the inlet and outlet were connected to M6 pressure ring adapter hard tubes (outer diameter 3.2 mm×inner diameter 1.6 mm). 2 wt.% Pt / Al 2 O 3 The catalyst was coated on the bottom of the reactor, and fully hydrogenated dibenzyltoluene was introduced from the inlet at an inlet flow rate of 10 ml / h. The dehydrogenation of fully hydrogenated dibenzyltoluene was tested. 2 The dehydrogenation of fully hydrogenated dibenzyltoluene was carried out in a cylindrical stirred tank reactor with a diameter of 110 mm × 110 mm. 2 O 3 The experimental temperature is 290℃, the working pressure is 1Mpa, and the reactor material is stainless steel.

[0051] The change in reactant concentration was calculated based on the number of moles of hydrogen produced during the reaction. The hydrogen production was calculated using the following formula: Hydrogen production = actual experimental hydrogen production / maximum theoretical hydrogen production × 100%.

[0052] The experimental results are as follows Fig.13 As shown, from Fig.13 It can be seen that, compared with the stirred tank reactor, the radial microreactor of the present invention can significantly improve the dehydrogenation yield of fully hydrogenated dibenzyltoluene.

[0053] Example 4: A microchannel experimental group A, a microchannel experimental group B with added fins, and a control group were set; wherein the experiments of the experimental groups A and B were Figure 1 The 2 wt.% Pt / Al 2 O 3 The catalyst is coated on the bottom of the reactor; the annular microchannel area includes 20 18.5mm×1mm×1mm straight microchannel walls. In addition, straight secondary microchannel walls are set between the two straight microchannel walls. There are 20 secondary microchannel walls in the entire annular microchannel area, with a size of 12mm×1mm×1mm. The only difference between experimental group B and experimental group A is that fins are set to prevent bubble backflow. Specifically, a circle of 20 circular needle columns (diameter 0.6mm, evenly distributed around the circumference) are arranged 1mm away from the edge of the microchannel entrance. The vertical distance between the center of the needle column and the center axis of the channel wall is 0.9mm; the inlet width of the microchannel is 1 mm, and the maximum channel size is 3 mm. The inlet and outlet are connected to M6 pressure ring adapter hard pipes (outer diameter 3.2mm×inner diameter 1.6mm), and 3mm is reserved between the inlet position of the microchannel and the edge of the chamber inlet. The control group is as follows Fig.14 The parallel microchannel reactor chamber shown was used for comparative experiments. The inlet and outlet spacing of the parallel microchannels was 50 mm. There were 26 parallel microchannels in total. The microchannel wall was 45 mm long and 1 mm wide, and the channel spacing was 1 mm.

[0054] Fully hydrogenated dibenzyltoluene was introduced from the inlet at different inlet flow rates, the experimental temperature was 290°C, the working pressure was 1Mpa, and the reactor material was stainless steel. The experimental results are as follows Fig.15 As shown, compared with the parallel microchannel reactor, the conversion rate of the radial microreactor with needle columns and the radial microreactor of the present invention is significantly higher than that of the parallel microchannel reactor; the radial microchannel with needle columns can further increase the conversion rate by about 10% under high inlet flow rate, and the main reason is that the design of the needle column fins further prevents the backflow of bubbles, thereby allowing the material to flow more smoothly.

[0055] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

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, and is 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 radial microreactor according to claim 1, characterized in that: The radial microreactor comprises a reactor bottom plate and a cover plate which can be buckled with each other, the reactor bottom plate is processed with the reactor chamber, and the cover plate buckles 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 radial microreactor according to claim 2, 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 radial microreactor according to claim 1, 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 radial microreactor according to claim 1, characterized in that: The surface of the microchannel wall is embedded or coated with a dehydrogenation or oxygen evolution catalyst.

6. The liquid phase dehydrogenation or oxygen evolution method based on 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 radial microreactor according to claim 1, 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 radial microreactor according to claim 1, 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 0-2mm larger than the inlet diameter, and the distance between adjacent fins in the same circle does not exceed 0.5mm; the fins of adjacent circles are staggered, and the distance between two adjacent circles does not exceed 0.5mm.

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