A kind of minimal surface reaction unit and microchannel reaction device

Abstract

This application relates to a minimal surface reaction unit and a microchannel reaction device. The minimal surface reaction unit includes a unit body used in the microchannel reaction device, wherein the unit body is separated into reactant channels and heat exchange medium channels by minimal surface boundary walls. The microchannel reaction device includes a shell with a loading channel formed on the shell, and the loading channel is filled with the minimal surface reaction unit. By introducing the minimal surface unit, the microchannel reaction device of this application can significantly increase the specific surface area and improve the heat transfer coefficient, resulting in better mass and heat transfer performance and reactant mixing effect. It can effectively solve the core pain points of existing microchannel reaction devices in continuous flow chemical reactions, and is suitable for complex continuous flow reaction scenarios such as strongly exothermic and multiphase flow, thus facilitating the industrialization and upgrading of continuous flow technology.

Description

Technical Field

[0001] This application relates to the technical field of microchannel reactions, specifically to a minimal surface reaction unit and a microchannel reaction device. Background Technology

[0002] In the field of continuous flow reactions in chemical engineering, continuous flow technology, as an innovative process intensification method, has gradually replaced the traditional batch reaction mode and is widely used in fine chemicals, pharmaceutical intermediate synthesis, and high-risk reactions (such as nitration and diazotization). Its core advantage lies in achieving continuous and precise control of the reaction, reducing reaction risks, and improving production efficiency and product purity. However, current mainstream microchannel reactors still face key bottlenecks in practical industrial applications: the flow channel configurations of traditional microchannels are mostly simple straight channels or serpentine channels with limited specific surface area, resulting in lower-than-expected mass and heat transfer efficiency. Especially in multiphase flow systems (gas-liquid-solid), localized uneven mass transfer and insufficient material mixing are prone to occur, which in turn affects reaction conversion rate and product selectivity. At the same time, for highly exothermic and fast-reaction continuous flow reactions...

[0003] Traditional microchannel reaction vessels, such as the microchannel reactor disclosed in CN109078590B, suffer from insufficient heat exchange capacity, susceptibility to localized overheating, and the potential for side reactions, even posing safety hazards. These shortcomings severely restrict the large-scale application of continuous flow technology in complex chemical reactions. Therefore, developing a microchannel reaction structure that can significantly improve mass and heat transfer performance and mixing efficiency has become an urgent need in the field of continuous flow chemical reactions. Summary of the Invention

[0004] To address the problems existing in the prior art, one objective of this application is to provide a minimally curved surface reaction unit suitable for microchannel reactors. Another objective is to provide a microchannel reactor with a minimally curved surface reaction unit. By introducing minimally curved surface units, the microchannel reactor of this application can significantly increase the specific surface area and improve the heat transfer coefficient, resulting in better mass and heat transfer performance and reactant mixing effect.

[0005] The present application describes a minimal curved surface reaction unit, which includes a unit body used in a microchannel reaction device. The unit body is separated into reactant channels and heat exchange medium channels by minimal curved surface boundary walls.

[0006] The unit body satisfies the control equation, which is used to constrain the length and width of the reactant channel, as well as the offset between the cross-sectional area of ​​the reactant channel and the cross-sectional area of ​​the heat exchange medium channel.

[0007] The governing equation is expressed as follows: ; in, The first length adjustment factor indicates that the reactant channel is in Length adjustment factor in the direction; This is the second length adjustment factor, representing the reactant channel in... Length adjustment factor in the direction; The third length adjustment factor indicates that the reactant channel is in Length adjustment factor in the direction; The first width adjustment factor indicates that the reactant channel is in Width adjustment factor in the direction; The second width adjustment factor indicates that the reactant channel is in Width adjustment factor in the direction; The third width adjustment factor indicates that the reactant channel is in Length adjustment factor in the direction; This indicates the offset between the cross-sectional area of ​​the reactant channel and the cross-sectional area of ​​the heat exchange medium channel.

[0008] Preferably, the first length adjustment coefficient Second length adjustment coefficient and the third length adjustment factor The range of values ​​is .

[0009] Preferably, the first length adjustment coefficient The second length adjustment factor is 5. and the third length adjustment factor All are 1; Alternatively, the second length adjustment factor The first length adjustment coefficient is 5. and the third length adjustment factor All are 1; Alternatively, the third length adjustment coefficient The first length adjustment coefficient is 5. Second length adjustment coefficient All are 1.

[0010] Preferably, the first width adjustment coefficient Second width adjustment coefficient and the third width adjustment factor The range of values ​​is .

[0011] Preferably, the first width adjustment coefficient The second width adjustment factor is 3. and the third width adjustment factor All are 1; Alternatively, the second width adjustment factor The first width adjustment coefficient is 3. and the third width adjustment factor All are 1; Alternatively, the third width adjustment coefficient The first width adjustment coefficient is 3. and the second width adjustment coefficient All are 1.

[0012] Preferably, the minimum side length of the unit body is The offset satisfy: .

[0013] Preferably, the offset Equals 0.1 .

[0014] Preferably, the side length of the unit body is in the range of 2.5mm to 20mm.

[0015] Preferably, the thickness of the minimal curved surface boundary wall ranges from 0.5 mm to 2.5 mm.

[0016] Preferably, the reactant channel includes a plurality of sequentially connected sub-channels, each of the sub-channels including a first flow channel and four second flow channels. The four second flow channels are distributed in pairs at both ends of the first flow channel and are all connected to the first flow channel. The two second flow channels located at the same end extend away from each other from the axis of the first flow channel.

[0017] Preferably, the reactant channel is provided with a turbulence structure for prolonging the reactant flow time.

[0018] Preferably, the turbulence structure includes a plurality of turbulence columns and / or groups of turbulence columns spaced apart along the flow direction of the reactants, wherein the cross-section of the turbulence columns is one or more of the following: circular, triangular, V-shaped, arc-shaped, and square.

[0019] This application discloses a microchannel reaction device, comprising a housing and miniature curved surface reaction units as described above. The housing has a loading channel and a reactant inlet, a reactant outlet, a heat exchange medium inlet, and a heat exchange medium outlet connected to the loading channel. A plurality of miniature curved surface reaction units are sequentially arranged in the loading channel along the flow direction of the loading channel, and the reactant channels of adjacent miniature curved surface reaction units are sequentially connected to form a reactant flow channel. The heat exchange medium channels of adjacent miniature curved surface reaction units are sequentially connected to form a heat exchange medium flow channel. The two ends of the reactant flow channel are respectively connected to the reactant inlet and the reactant outlet, and the two ends of the heat exchange medium flow channel are respectively connected to the heat exchange medium inlet and the heat exchange medium outlet.

[0020] Preferably, the volume of the loading channel is The volume of the reaction flow channel is The volume of the heat exchange medium flow channel is ,satisfy: .

[0021] Preferably, the volume of the loading channel is The volume of the reaction flow channel is ,satisfy: .

[0022] The advantages of the minimal curved surface reaction unit and microchannel reaction device described in this application are as follows: This application combines the characteristics of microchannel reactions to design a minimal curved surface reaction unit suitable for microchannel reaction devices. Applying this minimal curved surface reaction unit to microchannel reaction devices enables the microchannel reaction devices to have the advantages of large heat exchange area and precise process control. Compared with traditional microchannel reaction devices, it greatly increases the heat exchange area and significantly improves the mass and heat transfer performance of microchannel reaction devices. The minimal curved surface reaction unit of this application can generate a strong turbulent effect by setting a turbulence structure in the reactant channel and combining the alternating design of the first and second flow channels. The reactant mixing degree at each flow rate is significantly better than that of traditional devices, effectively improving the reactant mixing effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a minimal curved surface reaction unit structure as described in this application (the reactant channel and heat exchange medium channel are materialized in the figure for easier understanding). Figure 2 This is a schematic diagram of the physical structure of the reactant channel described in this application; Figure 3 This is a schematic diagram of the physical structure of the heat exchange medium channel described in this application; Figure 4 This is a schematic diagram of the structure of Embodiment 1 of the turbulence structure described in this application; Figure 5 This is a schematic diagram of the structure of Embodiment 2 of the turbulence structure described in this application; Figure 6 This is a schematic diagram of the structure of embodiment 3 of the turbulence structure described in this application; Figure 7 This is a schematic diagram of the structure of embodiment 4 of the turbulence structure described in this application; Figure 8 This is an exploded view of the microchannel reaction device described in this application (only a portion of the minimal curved surface reaction units are shown). Figure 9 This is a schematic diagram of the internal structure of the microchannel reaction device described in this application (only a portion of the minimal curved surface reaction units are shown). Figure 10 This is a comparison of experimental results between the microchannel reactor and the jacketed reactor of this application; Figure 11 This is a comparison of the pressure drop and flow rate at the inlet and outlet of the microchannel reactor and the jacketed reactor of this application.

[0024] Explanation of reference numerals in the attached drawings: 1-Unit body, 11-Minimum curved surface boundary wall, 12-Reactant channel, 121-First flow channel, 122-Second flow channel, 123-Turbulence structure, 13-Heat exchange medium channel, 2-Shell, 21-Loading channel, 22-Reactant inlet, 23-Reactant outlet, 24-Heat exchange medium inlet, 25-Heat exchange medium outlet, 3-Cover plate. Detailed Implementation

[0025] like Figures 1-3 As shown, the minimal curved surface reaction unit of this application includes a unit body 1. The unit body 1 is separated by minimal curved surface boundary walls 11 to form staggered reactant channels 12 and heat exchange medium channels 13 for heat exchange. The reactant channels 12 are used to inject reactants, and the heat exchange medium channels 13 are used to inject heat exchange medium. The reactants and heat exchange medium exchange heat through the boundary walls to carry out a catalytic reaction. Specifically, the minimal curved surface is formed by 3D printing or additive manufacturing.

[0026] In this embodiment, the minimum surface reaction unit adopts a G-type minimum surface. In other feasible embodiments, the minimum surface reaction unit can be any one of S-type, D-type, L-type or GD hybrid type. This embodiment does not limit this.

[0027] Based on the structure and characteristics of the microchannel reactor, the applicant designed a microchannel unit that combines the high heat transfer efficiency of the microchannel unit with the advantages of high heat transfer efficiency, aiming to improve the mass and heat transfer efficiency of the microchannel reactor.

[0028] Specifically, unit body 1 is usually in the form of a cuboid or cube, and is established with one of its vertices as the origin of the coordinate system. In a spatial rectangular coordinate system, the coordinates of element body 1 are mutually perpendicular. direction, direction and direction.

[0029] Based on the aforementioned spatial rectangular coordinate system, the unit body 1 in this embodiment satisfies the following governing equations: ; This governing equation uses a combination of G-shaped curves and sinusoidal surfaces to give it sinusoidal wave characteristics.

[0030] in, , , For example, unit body 1 is in , , The spatial periodic frequencies in the three directions are specifically the length adjustment coefficients of reactant channel 12, used to adjust the projected lengths of reactant channel 12 in the three directions. The first length adjustment factor indicates that the reactant channel 12 is in Length adjustment factor in the direction; The second length adjustment factor indicates that the reactant channel 12 is in Length adjustment factor in the direction; The third length adjustment factor indicates that the reactant channel 12 is in Length adjustment factor in the direction; Since reactant channel 12 penetrates unit body 1, in actual operation, unit body 1 is... , , Adjust the side lengths in all three directions.

[0031] For example, when At that time, unit body 1 is in , , Extending proportionally in three directions, unit body 1 has a cube structure.

[0032] when At that time, unit body 1 is in Stretching in the direction, unit body 1 has a cuboid structure, in which... The side length in the direction is greater than that in the direction direction and Side length in the direction.

[0033] Similarly, At that time, unit body 1 is in direction and The components are stretched proportionally in the same direction, resulting in a cuboid structure for unit body 1. The side length in the direction is equal to that in The side length in the direction and greater than in Side length in the direction.

[0034] Similarly, this embodiment does not exhaustively list all possibilities.

[0035] By adjusting , , The value can be used to adjust the side length of the unit body 1, i.e. the projected length of the reactant channel 12, thereby adjusting the reaction process of the minimal surface reaction unit so that it can be used in a microchannel reaction device.

[0036] , , For example, unit body 1 is in , , The spatial amplitude in three directions, specifically the width adjustment coefficient of reactant channel 12, is used to adjust the spatial amplitude of reactant channel 12 in three directions. , , The total width of the cross-section in three directions. Specifically: The first width adjustment factor represents the reactant channel 12 in... Width adjustment factor in the direction; The second width adjustment factor represents the reactant channel 12 in... Width adjustment factor in the direction; The third width adjustment factor indicates that the reactant channel 12 is in Length adjustment factor in the direction; For example, when At that time, unit body 1 is in , , The spatial amplitudes in the three directions are equal, meaning that reactant channel 12 is in... , , The total width of the cross-section is equal in all three directions.

[0037] when At that time, reactant channel 12 in The total width of the cross section in the direction is greater than , Total width of the cross section in the direction.

[0038] when At that time, reactant channel 12 in The total width of the cross section in the direction is equal to The total width of the cross section in the direction and greater than Total width of the cross section in the direction.

[0039] Similarly, this embodiment does not exhaustively list all possibilities.

[0040] This represents the offset between the cross-sectional area of ​​the reactant channel 12 and the cross-sectional area of ​​the heat exchange medium channel 13, i.e., the difference between the cross-sectional areas of the two channels.

[0041] Specifically, when At that time, the cross-sectional area of ​​reactant channel 12 is equal to the cross-sectional area of ​​heat exchange medium channel 13.

[0042] when At that time, the maximum cross-sectional area of ​​reactant channel 12 is greater than the cross-sectional area of ​​heat exchange medium channel 13, and the difference increases with... The values ​​are negatively correlated.

[0043] when At that time, the cross-sectional area of ​​the heat exchange medium channel 13 is greater than the maximum cross-sectional area of ​​the reactant channel 12, and the difference is greater than that of the heat exchange medium channel 13. The values ​​are positively correlated.

[0044] By adjusting the offset The difference in cross-sectional area between the heat exchange medium channel 13 and the reactant channel 12 in the control unit body 1 can be limited.

[0045] This application proposes a control equation for a minimal curved surface reaction unit suitable for microchannel reactors. The structure of the minimal curved surface reaction unit can be controlled from three dimensions: the length of the reactant channel 12, the cross-sectional width of the reactant channel 12, and the difference in cross-sectional area between the reactant channel 12 and the heat exchange medium channel 13. This allows the fabricated minimal curved surface reaction unit to be well-suited for use in microchannel reactors, effectively enhancing heat and mass transfer.

[0046] Furthermore, in this embodiment, the first length adjustment coefficient Second length adjustment coefficient and the third length adjustment factor The range of values ​​is The minimal surface reaction unit structure defined by this range of values ​​is applicable to microchannel reaction devices.

[0047] Preferably, the first length adjustment coefficient The second length adjustment factor is 5. and the third length adjustment factor All are 1; Alternatively, the second length adjustment factor The first length adjustment factor is 5. and the third length adjustment factor All are 1; Alternatively, the third length adjustment factor The first length adjustment factor is 5. Second length adjustment coefficient All are 1.

[0048] That is, the first length adjustment coefficient Second length adjustment coefficient and the third length adjustment factor One of them is equal to 5, and the other two are 1. Through actual verification, this length adjustment coefficient can achieve better reactant mixing and heat exchange efficiency.

[0049] Furthermore, in this embodiment, the first width adjustment coefficient Second width adjustment coefficient and the third width adjustment factor The range of values ​​is The minimal surface reaction unit structure defined by this range of values ​​is applicable to microchannel reaction devices.

[0050] Preferably, the first width adjustment coefficient The second width adjustment factor is 3. and the third width adjustment factor All are 1; Alternatively, the second width adjustment factor The first width adjustment factor is 3. and the third width adjustment factor All are 1; Alternatively, the third width adjustment factor The first width adjustment factor is 3. Second width adjustment coefficient All are 1.

[0051] That is, the first width adjustment coefficient Second width adjustment coefficient and the third width adjustment factor One of the values ​​is 3, and the other two are 1. This length adjustment factor can be used to obtain a better reactant mixing degree and heat exchange efficiency.

[0052] Furthermore, in this embodiment, the minimum side length of unit body 1, that is, the length of the relatively smaller side, is... Offset satisfy: .

[0053] offset The offset is related to the side length of unit body 1. The value of the value is restricted, thereby controlling the difference in cross-sectional area between the reactant channel 12 and the heat exchange medium channel 13, so that the miniature curved surface reaction unit formed can be used in microchannel reaction devices and has good mixing effect and heat transfer efficiency.

[0054] Preferably, offset Equals 0.1 Practical verification has shown that this offset value enables the minimal surface reaction unit to achieve good mixing effect and heat transfer efficiency.

[0055] More specifically, the side length of the unit body 1 ranges from 2.5 mm to 20 mm. The thickness of the minimal curved surface boundary wall 11 ranges from 0.5 mm to 2.5 mm. These side length and wall thickness values ​​are applicable to microchannel reaction devices.

[0056] Details as follows Figures 4 to 7 As shown, the reactant channel 12 includes multiple sequentially connected sub-channels, which are approximately "I"-shaped. Each sub-channel includes a first flow channel 121 and four second flow channels 122. The four second flow channels 122 are distributed in pairs at both ends of the first flow channel 121 and are all connected to the first flow channel 121. The two second flow channels 122 located at the same end extend outwards from the axis of the first flow channel 121 in opposite directions, specifically extending outwards in an arc shape, making the sub-channel approximately "I"-shaped. Preferably, the cross-sectional area of ​​the second flow channel 122 is smaller than the cross-sectional area of ​​the first flow channel 121. The "I"-shaped sub-channel structure, combined with the small-channel-large-channel-small-channel structure, allows the reactants to be fully mixed when flowing through the reactant channel 12.

[0057] The reactant channel 12 is provided with a turbulence structure 123 for prolonging the reactant flow time. The turbulence structure 123 has at least four of the following embodiments: Example 1 Details as follows Figure 4 As shown, the turbulence structure 123 includes several V-shaped plates spaced apart along the length of the first flow channel 121, with the reactants flowing from above (with... Figure 4 Taking the direction shown as an example, after the second flow channel 122 flows into the first flow channel 121, it collides with the V-shaped plate. The reactants change their flow direction under the action of the V-shaped plate, which prolongs the flow time of the reactants in the first flow channel 121 and increases the contact area.

[0058] Example 2 Details as follows Figure 5 As shown, the turbulence structure 123 includes several groups of triangular plates arranged at intervals along the length of the first flow channel 121. Each group of triangular plates includes two parallel triangular plates, and the axis of the triangular plates is in the same direction as the length of the first flow channel 121. The reactants flow from above (within the direction shown). Figure 5 Taking the direction shown as an example, after the second flow channel 122 flows into the first flow channel 121, it collides with the triangular plate. The reactants change their flow direction under the action of the triangular plate, which prolongs the flow time of the reactants in the first flow channel 121 and increases the contact area.

[0059] Example 3 Details as follows Figure 6 As shown, the turbulence structure 123 includes several groups of square plates arranged at intervals along the length of the first flow channel 121. Each group of square plates includes four square plates arranged side by side, with gaps between adjacent square plates. The reactants flow from above (within...) Figure 6 Taking the direction shown as an example, after the second flow channel 122 flows into the first flow channel 121, it collides with the square plate. The reactants change their flow direction under the action of the square plate, which prolongs the flow time of the reactants in the first flow channel 121 and increases the contact area.

[0060] Example 4 Details as follows Figure 7 As shown, the turbulence structure 123 includes three cylinders, two of which are distributed within two second flow channels 122 at the same end, and the other is distributed within a first flow channel 121 near that end. The reactants flow from above (within...) Figure 7 Taking the direction shown as an example, after the second flow channel 122 flows into the first flow channel 121, when it flows to the lower end of the first flow channel 121, it collides with the cylinder located therein and changes its flow direction. Then it flows from both sides into the second flow channel 122 below, where it changes its flow direction and is fully mixed by the cylinder therein.

[0061] All four different flow-delay structures 123 described above can extend the mixing time of the reactants, change the flow direction of the reactants, and increase the contact area. They can be selected and configured according to requirements. It should be noted that conventional modifications made by those skilled in the art to the shape or arrangement of the flow-delay structure 123 based on the above four embodiments should also fall within the scope of protection of this application.

[0062] This embodiment also provides a microchannel reaction device, detailed as follows: Figure 8 , Figure 9 As shown, the device includes a housing 2 and the aforementioned miniature curved surface reaction units. The housing 2 has a square box structure with a hollow interior. Its interior is divided by partitions to form a serpentine loading channel 21, which is used to fill the miniature curved surface reaction units. Specifically, multiple miniature curved surface reaction units are sequentially filled into the loading channel 21 along its extension direction. Adjacent miniature curved surface units are tightly fitted together, aligning the reactant channels 12 and the heat exchange medium channels 13. This allows the reactant channels 12 of the multiple miniature curved surface reaction units to connect sequentially, forming a reactant flow channel, and the heat exchange medium channels 13 of the multiple miniature curved surface reaction units to connect sequentially, forming a heat exchange medium flow channel. One side of the housing 2 is the bottom wall, and the other side is sealed by a cover plate 3.

[0063] The shell 2 is provided with a reactant inlet 22, a reactant outlet 23, a heat exchange medium inlet 24, and a heat exchange medium outlet 25. The number of reactant inlets 22 is usually at least two to allow the input of at least two different reactants. The reactants are input into the reactant flow channel from the reactant inlet 22 and flow through each minimal surface reaction unit in sequence. Similarly, the heat exchange medium is input into the heat exchange medium flow channel from the heat exchange medium inlet 24. The reactants and the heat exchange medium exchange heat through the minimal surface boundary 11. After the reactants have fully reacted in the reactant flow channel, they flow out from the reactant outlet 23, and the heat exchange medium flows out from the heat exchange medium outlet 25.

[0064] In a specific embodiment, a sealing plate for sealing the heat exchange medium flow channel is provided at the reactant inlet 22 and the reactant outlet 23. Specifically, holes are made on the sealing plate at positions corresponding to the reactant inlet 22 and the reactant outlet 23, and the remaining positions are sealed. Thus, the heat exchange medium inlet 24 and the heat exchange medium outlet 25 can be sealed by the sealing plate to prevent reactants from entering the heat exchange medium flow channel.

[0065] Similarly, the reactant inlet 22 and reactant outlet 23 at the heat exchange medium inlet 24 and heat exchange medium outlet 25 can be sealed with a sealing plate to prevent the heat exchange medium from entering the reaction flow channel.

[0066] The microchannel reactor in this embodiment can significantly improve the heat exchange efficiency between reactants and heat exchange medium by introducing extremely small curved surface reaction units, thus enabling the microchannel reactor to have better mass and heat transfer performance and reactant mixing effect.

[0067] Furthermore, in this embodiment, the volume of the loading channel 21 is... The volume of the reaction logistics channel is The volume of the heat exchange medium flow channel is ,satisfy: .

[0068] This structure ensures that the sum of the volumes of the reactant flow channels and the heat exchange medium flow channels of the minimal curved surface reaction unit accounts for a certain proportion of the volume of the loading channel 21, so as to guarantee the improvement effect of the minimal curved surface reaction unit on the microchannel reaction device.

[0069] Furthermore, in this embodiment, the volume of the loading channel 21 is... The volume of the reaction flow channel is ,satisfy: .

[0070] This structure limits the proportion of the volume of the reaction channel in the loading channel 21 to ensure that the microchannel reactor can accommodate a sufficient amount of reactants for reaction.

[0071] The following will, in conjunction with comparative examples, detail the differences between the microchannel reaction device of this embodiment and conventional microchannel reaction devices.

[0072] The microchannel reactor equipped with a minimal curved surface reaction unit described in this embodiment is used as an example, while a conventional jacketed microchannel reactor is used as a comparative example.

[0073] The liquid holding capacity of the minimally curved surface microreactor is the same as that of a traditional jacketed microreactor, which is 10 mL. The cross-sectional area of ​​the reactant channel 12 is approximately 1 mm². 2 The size of the microchannel reactor in this embodiment is about 1 / 2 that of a jacketed reactor.

[0074] The heat transfer coefficients were measured using the microchannel reactor of this embodiment and a conventional jacketed reactor at different flow rates, and the results are as follows: Figure 10 And as shown in Table 1 below: Table 1. As shown in the graphs, the heat transfer coefficients of both devices increase with increasing flow rate, which is consistent with the heat transfer law. Furthermore, the heat transfer coefficient of the microchannel reactor in this embodiment is more than three times that of the conventional plate heat exchanger at all tested flow rates. This clearly demonstrates that the microchannel reactor in this embodiment has a significantly better heat transfer coefficient than the conventional jacketed heat exchanger.

[0075] Further comparative experiments were conducted, using parallel competing reactions to characterize the efficiency of micromixing. This experiment, similar in principle, involved preparing a diluted sulfuric acid solution and an alkaline solution mixed with boric acid, potassium iodide, and potassium iodate at room temperature. Both solutions were then injected into the microchannel reaction apparatus and jacketed reaction device of this embodiment using a plunger pump. The resulting test reactions included two competing reactions with different rates: one producing I₃ that absorbs ultraviolet light. -The rapid reaction and the ultrafast neutralization reaction of boric acid, which does not produce ultraviolet light absorption, can lead to the generation of I3 that absorbs ultraviolet light if the mixing degree of the microchannel reaction device in this embodiment is poor. - The UV transmittance will be less than 100%, therefore the closer the UV transmittance is to 100%, the better the mixing effect of the device on the reactants.

[0076] Therefore, Table 2 below shows the curves of reaction flow rate and UV transmittance. It can be seen from the table that the modified miniature surface has good mixing degree. As the flow rate increases, the mixing degree gradually increases, and the performance is better than that of the comparative example.

[0077] Table 2. Figure 11 Table 3 below shows the pressure drop-flow rate at the inlet and outlet of the microchannel reactor in this embodiment and compared with a conventional jacketed reactor. Deionized water was used as the solution. Figure 11 As can be seen, the pressure drop gradually increases with the increase of flow rate, which is in line with the pressure drop law. The pressure drop of the microchannel reactor in this embodiment is lower than that of the conventional jacketed reactor.

[0078] Table 3. Furthermore, four different implementations of the aforementioned turbulence structure 123 were verified.

[0079] exist Figure 4 In the embodiment shown, V-shaped plates are added inside the channel with an angle of 90 degrees. Four V-shaped plates are arranged in sequence inside the channel to ensure sufficient turbulence. This structure can maintain a low pressure drop while keeping the mixture in place.

[0080] exist Figure 5 In the illustrated embodiment, three separate triangular plates are added inside the channel, arranged sequentially within the channel. This helps maintain the degree of liquid mixing. The high-speed fluid generated by the transition from the large channel to the small channel, and the cavitation effect created by the high-speed fluid entering the larger open channel, ensure thorough mixing.

[0081] exist Figure 6 In the illustrated embodiment, separate, unevenly distributed square plates are added to the channel, which are also distributed sequentially inside the pipe. This helps to increase the Dean number of the fluid, which can effectively mix heterogeneous liquids, especially suitable for rapidly stratified chemical liquids.

[0082] exist Figure 7 In the illustrated embodiment, a cylinder is added at the junction of the three pipes. This effectively prevents dead zones in the liquid flow and reduces resistance, allowing the liquid containing solids to pass through effectively.

[0083] The structures tested in the above embodiments are in accordance with Figures 4-7 The structural manufacturing and mixing degree test results are shown in Table 4 below. As can be seen in Table 4, the various turbulence structures 123 described above have good mixing performance at various flow rates, and have excellent mixing performance at flow rates above 200 mL / min.

[0084] Table 4. Furthermore, this application further verifies the reactant mixing effect of reactant channel 12 under different values ​​of length adjustment coefficient, width adjustment coefficient, and offset in the control equation, to prove that the coefficient values ​​in this embodiment have superior effects. Specifically, for the first length adjustment coefficient... Second length adjustment coefficient Third length adjustment coefficient First width adjustment coefficient Second width adjustment coefficient Third width adjustment coefficient and offset Different values ​​were used and actual experiments were conducted to obtain the reaction mixture degree measurement results, which are shown in Table 5 below.

[0085] Table 5. As shown in the table above, when the first length adjustment coefficient... Second length adjustment coefficient Third length adjustment coefficient The ratio is 1:1:5, and the first width adjustment coefficient is... Second width adjustment coefficient Third width adjustment coefficient The ratio is 1:1:3, and The value is 0.1 In the above-mentioned experimental example 14, the reactant channel 12 and the heat exchange medium channel 13 are coordinated in size, with moderate pressure, good heat exchange and mixing, no adverse indicators, and the effect is significantly better than other experimental examples. It can be seen that the values ​​of each length adjustment coefficient, width adjustment coefficient and offset in this embodiment have better heat exchange and mixing effects.

[0086] Furthermore, this application also verified the effect of reactant viscosity on pressure in reactant channel 12 under different values ​​of length adjustment coefficient, width adjustment coefficient and offset in the control equation. The test results are shown in Table 6 below.

[0087] Table 6. To further verify the effectiveness of this device in exothermic reactions, the following experiments were conducted in this application.

[0088] Experimental Example 1 The nitration of benzene is a typical rapid and strongly exothermic reaction, which mainly produces nitrobenzene and the side reaction is dinitration to produce m-dinitrobenzene. When using ordinary microchannel devices, heat exchange may not be timely, which may lead to runaway reaction temperature. The adiabatic temperature rise can reach 30~50℃, which requires extremely high heat exchange efficiency of the reaction device.

[0089] Experimental conditions: Reaction raw materials: benzene (99.9%), mixed acid (H2SO4:HNO3 = 2:1, molar ratio); Test apparatus: The embodiment uses the minimal curved surface microchannel reaction device described in this embodiment, with the following unit parameters: side length 5mm, wall thickness 1mm, m / q / n=1:1:5, α / β / γ=1:1:3, offset=0.1.

[0090] The comparative experiments used traditional jacketed microchannel reactors, with a liquid holding capacity of 50 mL.

[0091] Reaction parameters: reaction temperature 50~60℃, feed flow rate 100~150mL / min, benzene to mixed acid feed molar ratio 1:1.05; The experimental results are shown in Table 7 below.

[0092] Table 7. As shown in Experimental Example 1, the yield of the microchannel reactor with minimal curved surface described in this application is significantly better than that of the traditional jacketed microchannel reactor in the nitration reaction of benzene, and the temperature fluctuation range is smaller, making it suitable for the nitration reaction of benzene.

[0093] Experiment Example 2 The oxidation reaction of dimethyl sulfoxide (DMSO) is a typical strongly exothermic fine chemical reaction. Industrially, dimethyl sulfone (DMS) is often prepared by oxidizing DMSO. This reaction releases a large amount of heat (adiabatic temperature rise of about 45~60℃).

[0094] 1. Experimental materials Dimethyl sulfoxide (DMSO, purity 99.9%), hydrogen peroxide (60% mass fraction, industrial grade), dilute sulfuric acid (2 mol / L, catalyst); raw material molar ratio: DMSO:H2O2:H2SO4 = 1:1.05:0.02.

[0095] 2. Testing apparatus The embodiment uses the minimal curved surface microchannel reaction device described in this application, with the following parameter configuration: The unit body has a side length of 5mm and a minimum curved surface wall thickness of 1mm; the length adjustment coefficient m:q:n=1:1:5, the width adjustment coefficient α:β:γ=1:1:3, and the offset=0.1; the reactant channel is equipped with the square plate turbulence structure described in Example 3 above to enhance reactant mixing and has a liquid holding capacity of 50mL.

[0096] The comparative example used a traditional jacketed microchannel reactor with a liquid holding capacity of 50 mL, a straight channel configuration, and no enhanced mixing structure.

[0097] The experimental results are shown in Table 8 below.

[0098] Table 8. As shown in Experimental Example 2, the miniature curved surface microchannel reactor described in this application has significantly better yield performance in the oxidation reaction of dimethyl sulfoxide (DMSO) than the traditional jacketed microchannel reactor, and has a smaller temperature fluctuation range, making it suitable for the oxidation reaction of dimethyl sulfoxide (DMSO).

[0099] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application.

[0100] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this application.

Claims

1. A minimal surface reaction unit, characterized in that, The invention includes a unit body used in a microchannel reactor, wherein the unit body is separated into reactant channels and heat exchange medium channels by a minimal curved surface boundary; The unit body satisfies the control equation, which is used to constrain the length and width of the reactant channel, as well as the offset between the cross-sectional area of ​​the reactant channel and the cross-sectional area of ​​the heat exchange medium channel. The governing equation is expressed as follows: in, The first length adjustment factor indicates that the reactant channel is in Length adjustment factor in the direction; This is the second length adjustment factor, representing the reactant channel in... Length adjustment factor in the direction; The third length adjustment factor indicates that the reactant channel is in Length adjustment factor in the direction; The first width adjustment factor indicates that the reactant channel is in Width adjustment factor in the direction; The second width adjustment factor indicates that the reactant channel is in Width adjustment factor in the direction; The third width adjustment factor indicates that the reactant channel is in Length adjustment factor in the direction; This indicates the offset between the cross-sectional area of ​​the reactant channel and the cross-sectional area of ​​the heat exchange medium channel.

2. The minimal surface reaction unit according to claim 1, characterized in that, First length adjustment coefficient Second length adjustment coefficient and the third length adjustment factor The range of values ​​is .

3. The minimal surface reaction unit according to claim 2, characterized in that, First length adjustment coefficient The second length adjustment factor is 5. and the third length adjustment factor All are 1; Alternatively, the second length adjustment factor The first length adjustment coefficient is 5. and the third length adjustment factor All are 1; Alternatively, the third length adjustment coefficient The first length adjustment coefficient is 5. Second length adjustment coefficient All are 1.

4. The minimal surface reaction unit according to claim 2 or 3, characterized in that, First width adjustment coefficient Second width adjustment coefficient and the third width adjustment factor The range of values ​​is .

5. The minimal surface reaction unit according to claim 4, characterized in that, First width adjustment coefficient The second width adjustment factor is 3. and the third width adjustment factor All are 1; Alternatively, the second width adjustment factor The first width adjustment coefficient is 3. and the third width adjustment factor All are 1; Alternatively, the third width adjustment coefficient The first width adjustment coefficient is 3. and the second width adjustment coefficient All are 1.

6. The minimal surface reaction unit according to claim 5, characterized in that, The minimum side length of the unit body is The offset satisfy: 。 7. The minimal surface reaction unit according to claim 6, characterized in that, The offset Equals 0.1 .

8. The minimal surface reaction unit according to claim 6 or 7, characterized in that, The side length of the unit body ranges from 2.5mm to 20mm.

9. The minimal surface reaction unit according to claim 8, characterized in that, The thickness of the minimal curved surface boundary wall ranges from 0.5 mm to 2.5 mm.

10. The minimal surface reaction unit according to claim 1, characterized in that, The reactant channel includes multiple sequentially connected sub-channels. Each sub-channel includes a first flow channel and four second flow channels. The four second flow channels are distributed in pairs at both ends of the first flow channel and are all connected to the first flow channel. The two second flow channels located at the same end extend away from each other from the axis of the first flow channel.

11. The minimal surface reaction unit according to claim 10, characterized in that, The reactant channel is equipped with a turbulence structure to prolong the reactant flow time.

12. The minimal surface reaction unit according to claim 11, characterized in that, The turbulence structure includes several turbulence columns and / or groups of turbulence columns spaced apart along the direction of reactant flow. The cross-section of the turbulence columns is one or more of the following: circular, triangular, V-shaped, arc-shaped, and square.

13. A microchannel reaction device, characterized in that, The device includes a housing and a miniature curved surface reaction unit as described in any one of claims 1 to 12. The housing has a loading channel and a reactant inlet, a reactant outlet, a heat exchange medium inlet, and a heat exchange medium outlet connected to the loading channel. A plurality of miniature curved surface reaction units are sequentially arranged in the loading channel along the flow direction of the loading channel. The reactant channels of adjacent miniature curved surface reaction units are sequentially connected to form a reactant flow channel, and the heat exchange medium channels of adjacent miniature curved surface reaction units are sequentially connected to form a heat exchange medium flow channel. The two ends of the reactant flow channel are respectively connected to the reactant inlet and the reactant outlet, and the two ends of the heat exchange medium flow channel are respectively connected to the heat exchange medium inlet and the heat exchange medium outlet.

14. The microchannel reaction device according to claim 13, characterized in that, The volume of the loading channel is The volume of the reaction flow channel is The volume of the heat exchange medium flow channel is ,satisfy: 。 15. The microchannel reaction device according to claim 14, characterized in that, The volume of the loading channel is The volume of the reaction flow channel is ,satisfy: 。

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