Microreactor and microchannel thereof

Abstract

The present application aims to provide a kind of microchannel for microreactor, which includes a plurality of microchannel units in series, each microchannel unit includes a plurality of straight pipes and a plurality of curved pipes, the straight pipes respectively extend along a straight line, the length of each straight pipe is 0.5mm to 5mm, the curved pipes respectively extend along a curve, connect two adjacent straight pipes, the extension direction of the two adjacent straight pipes connected forms a 90° angle. Wherein, the cross section of any position of the microchannel is circular, and the cross section area of any position of the microchannel is constant, the radius of the cross section is 0.05mm to 2.5mm. Through the microchannel, the mixing, mass transfer and heat transfer effect of the fluid in the microreactor can be improved.

Description

Technical Field

[0001] This invention relates to the field of microreactor technology, and more particularly to a microreactor and its microchannels. Background Technology

[0002] Microreactor technology emerged in the 1990s and is a cutting-edge field involving multiple disciplines such as chemical engineering, mechanical engineering, physics, and chemistry. Microreactors possess advantages such as small internal channel dimensions, rapid heat and mass transfer rates, high controllability, intrinsic safety, low process energy consumption, high integration, and minimal scale-up effects. They can improve the selectivity and yield of target products, as well as the comprehensive utilization rate of resources and energy, and are of great significance for achieving energy conservation, emission reduction, and sustainable development in chemical processes.

[0003] The design of microchannels and microreactors has always been a key focus and hot topic in the field of microreactor technology, and also a challenge in the practical application of microreactor technology. A basic requirement for microchannel design is to obtain high mass and heat transfer rates. Various microchannels with special structures have been reported in the literature, such as microchannels with internal obstacles, spiral microchannels, microchannels with branching-converging structures, and microchannels with periodic contraction-expansion structures.

[0004] Most existing microreactors employ one of the aforementioned microchannel structures, which can improve mass and heat transfer rates during the reaction process. However, these microchannel structures are complex, introducing turbulence into the fluid through obstacles, branches, and abrupt contractions, resulting in significant energy dissipation. Moreover, under certain flow conditions, structurally complex microchannels are prone to dead zones and fouling after prolonged use, making maintenance difficult. Therefore, designing and developing a microchannel with high mass and heat transfer efficiency and a simple structure is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a microchannel that can improve the mixing, mass transfer and heat transfer of fluids inside a microreactor.

[0006] Microchannels for achieving the aforementioned objectives, used in microreactors, comprise multiple microchannel units connected in series, each microchannel unit comprising:

[0007] Multiple straight conduits, each extending in a straight line, with a length of 0.5 mm to 5 mm; and

[0008] Multiple curved pipes extend along curves and connect adjacent straight pipes, with the extension directions of the two adjacent straight pipes forming a 90° angle.

[0009] The cross-section of the microchannel at any position is circular, with a radius of 0.05 mm to 2.5 mm, and the cross-sectional area of ​​the microchannel at any position remains constant.

[0010] In one or more embodiments, each of the microchannel units has the same configuration.

[0011] In one or more embodiments, the straight conduit includes a first straight conduit, a second straight conduit, a third straight conduit, a fourth straight conduit, a fifth straight conduit, a sixth straight conduit, a seventh straight conduit, and an eighth straight conduit, and the curved conduit includes a first curved conduit, a second curved conduit, a third curved conduit, a fourth curved conduit, a fifth curved conduit, a sixth curved conduit, a seventh curved conduit, and an eighth curved conduit.

[0012] Wherein, the first curved tube connects the first straight tube and the second straight tube, the first straight tube in the connected state is arranged along the first direction, and the second straight tube is arranged from the first curved tube along the negative direction of the second direction;

[0013] The second curved tube connects the second straight tube and the third straight tube, and the third straight tube is arranged along the first direction in the connected state;

[0014] The third curved tube connects the third straight tube and the fourth straight tube, and the fourth straight tube is arranged along the third direction in the connected state;

[0015] The fourth curved tube connects the fourth straight tube and the fifth straight tube, and the fifth straight tube is arranged along the first direction in the connected state;

[0016] The fifth curved tube connects the fifth straight tube and the sixth straight tube, and the sixth straight tube is arranged along the positive direction of the second direction in the connected state;

[0017] The sixth curved tube connects the sixth straight tube and the seventh straight tube, and the seventh straight tube is arranged along the first direction in the connected state;

[0018] The seventh curved tube connects the seventh straight tube and the eighth straight tube, and the eighth straight tube is arranged along the third direction in the connected state;

[0019] The eighth curved tube connects the eighth straight tube to the first straight tube of the adjacent microchannel unit, and the first straight tube of the adjacent microchannel unit is arranged along the first direction in the connected state;

[0020] Wherein, the first direction is perpendicular to the third direction, and the second direction is perpendicular to the plane containing the first direction and the third direction.

[0021] In one or more embodiments, the plurality of straight pipes are of the same length.

[0022] In one or more embodiments, the radii of curvature of the plurality of curved pipes are all the same.

[0023] In one or more embodiments, the radius of curvature of the curved conduit is 1.4 to 3 times the radius of the cross-section.

[0024] In one or more embodiments, an inlet conduit and an outlet conduit are included;

[0025] The inlet pipe is connected to the first straight pipe of the microchannel unit located at the microchannel inlet, and the outlet pipe is connected to the eighth curved pipe of the microchannel unit located at the microchannel outlet.

[0026] On the other hand, according to some embodiments of this application, a microreactor is also provided, which includes a reaction microchannel and a heat exchange microchannel, wherein the reaction microchannel adopts the microchannel described in the previous one or more embodiments;

[0027] The reaction microchannel is composed of multiple microchannel units connected in series in the same plane;

[0028] The heat exchange microchannel includes a first pipeline group and a second pipeline group that are connected to each other. The first pipeline group and the second pipeline group are respectively arranged in different planes and separated from each other by a distance. The reaction microchannel is sandwiched between the first pipeline group and the second pipeline group. In the orthographic projection seen in the height direction of the microreactor, the reaction microchannel is covered by the heat exchange microchannel.

[0029] In one or more embodiments, the microchannels and / or the tubing within the first tubing group and / or the second tubing group are respectively arranged in a meandering direction.

[0030] In one or more embodiments, the cross-section of the pipes constituting the first pipe group and / or the second pipe group is rectangular, the width of the rectangle being 3 mm to 5 mm and the height of the rectangle being 1 mm to 3 mm.

[0031] In one or more embodiments, the inlet of the reaction microchannel and the inlet of the heat exchange microchannel are respectively located at opposite corners of the microreactor.

[0032] The beneficial effects of this invention are as follows:

[0033] This microchannel allows for continuous 90-degree turns in its extension direction in three-dimensional space, generating a secondary flow dominated by Dean vortices within the fluid. This enhances fluid turbulence, thereby improving mixing, mass transfer, and heat transfer within the fluid. Dean vortices are generated because when fluid passes through a curved pipe, it experiences centrifugal force, which, under certain conditions, produces two symmetrical vortices perpendicular to the main flow direction. The two vortices rotate clockwise and counterclockwise, respectively; these are the Dean vortices. Furthermore, unlike existing microchannel structures, this microchannel contains no obstructions, preventing fluid splitting and recombination, and minimizing dead zones and dead ends. The microchannel's longitudinal cross-section is circular with a constant diameter, further reducing dead zones and significantly improving the pressure drop in the microreactor.

[0034] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0036] Figure 1 A three-dimensional schematic diagram of a microchannel according to some embodiments of this application is shown;

[0037] Figure 2 A perspective schematic diagram of a microchannel unit according to some embodiments of this application is shown;

[0038] Figure 3 A three-dimensional schematic diagram of a microreactor according to some embodiments of this application is shown;

[0039] Figure 4 A velocity vector diagram on a longitudinal section of a microchannel according to some embodiments of this application is shown;

[0040] Figure 5 The results of comparing microreactors according to some embodiments of this application with existing microreactors are shown. Detailed Implementation

[0041] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0043] To address the problems existing in the prior art, on the one hand, according to some embodiments of this application, a microchannel for use in a microreactor is provided, such as... Figure 1 A three-dimensional schematic diagram of a microchannel according to some embodiments of the present application is shown. The microchannel 100 is composed of a plurality of microchannel units 1 connected in series, wherein the microchannel units 1 are connected in series means that two adjacent microchannel units 1 are connected in series with each other and internally connected.

[0044] Figure 2 A perspective view of a microchannel unit according to some embodiments of this application is shown. Each microchannel unit 1 includes multiple straight conduits 11 and multiple curved conduits 12. Each straight conduit 11 extends along a straight line and has a length of 0.5 mm to 5 mm. Each curved conduit 12 extends along a curve and connects two adjacent straight conduits 11. The extension directions of two adjacent straight conduits 11 connected by the curved conduit 12 form a 90° angle.

[0045] The cross-section of the microchannel 100 at any position is circular, the radius of the cross-section of the microchannel 100 is 0.05 mm to 2.5 mm, and the cross-sectional area of ​​the microchannel 100 at any position remains unchanged.

[0046] By employing a microchannel with the aforementioned configuration, the extension direction of the microchannel undergoes continuous 90-degree turns in three-dimensional space, generating a secondary flow dominated by Dean vortices within the fluid. This enhances fluid turbulence, thereby improving mixing, mass transfer, and heat transfer within the fluid. Dean vortices are generated because when fluid passes through a curved pipe, it experiences centrifugal force, which, under certain conditions, produces two symmetrical vortices perpendicular to the main flow direction. The directions of these two vortices are clockwise and counterclockwise, respectively; these two vortices are known as Dean vortices. Furthermore, unlike existing microchannel structures, the microchannel in this application contains no obstruction structures, preventing fluid splitting and recombination, and minimizing dead zones and dead ends. Simultaneously, the microchannel has a circular longitudinal section with a constant diameter, which, in addition to further reducing dead zones, significantly improves the pressure drop of the microreactor.

[0047] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In some embodiments of this microchannel, the microchannel is as follows: Figure 1 As shown, among the multiple microchannel units 1 constituting the microchannel 100, each microchannel unit 1 has the same configuration, thereby making the overall configuration of the microchannel 100 simpler and easier to process and manufacture.

[0049] In some embodiments of this microchannel, such as Figure 2 As shown, the straight conduit 11 constituting the microchannel unit 1 includes a first straight conduit 111, a second straight conduit 112, a third straight conduit 113, a fourth straight conduit 114, a fifth straight conduit 115, a sixth straight conduit 116, a seventh straight conduit 117, and an eighth straight conduit 118. The curved conduit 12 constituting the microchannel unit 1 includes a first curved conduit 121, a second curved conduit 122, a third curved conduit 123, a fourth curved conduit 124, a fifth curved conduit 125, a sixth curved conduit 126, a seventh curved conduit 127, and an eighth curved conduit 128.

[0050] The system comprises the following components: a first curved pipe 121 connects a first straight pipe 111 and a second straight pipe 112, with the first straight pipe 111 positioned along the first direction X, and the second straight pipe 112 positioned from the first curved pipe 121 along the negative direction of the second direction Z. A second curved pipe 122 connects the second straight pipe 112 and a third straight pipe 113, with the third straight pipe 113 positioned along the first direction X. A third curved pipe 123 connects the third straight pipe 113 and a fourth straight pipe 114, with the fourth straight pipe 114 positioned along the third direction Y. A fourth curved pipe 124 connects the fourth straight pipe 114 and a fifth straight pipe 115, with the fifth straight pipe 115 positioned along the first direction X. A fifth curved pipe 125 connects the fifth straight pipe 115 and a sixth straight pipe 116, with the sixth straight pipe 116 positioned along the positive direction of the second direction Z. The sixth curved tube 126 connects the sixth straight tube 116 and the seventh straight tube 117. In the connected state, the seventh straight tube 117 is arranged along the first direction X. The seventh curved tube 127 connects the seventh straight tube 117 and the eighth straight tube 118. In the connected state, the eighth straight tube 118 is arranged along the third direction Y. The eighth curved tube 128 connects the eighth straight tube 118 and the first straight tube of the adjacent microchannel unit (e.g., ...). Figure 2As shown, in the connected state, the first straight tubes of adjacent microchannel units are arranged along the first direction X. The first direction X is perpendicular to the third direction Y, and the second direction Z is perpendicular to the plane containing the first direction X and the third direction Y. It has been verified that by configuring each microchannel unit 1 constituting the microchannel 100 with the aforementioned configuration, not only can each microchannel unit 1 in the microchannel 100 have the same configuration, making it easy to manufacture, but the microchannel 100 as a whole with the aforementioned configuration can significantly improve the pressure drop of the microreactor. In the description of the embodiments of this application, the technical terms "first" and "second," such as "first straight tube" and "second straight tube," are only used to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0051] In some embodiments of this microchannel, multiple straight tubes 11 are of the same length. It has been verified that the microchannel 100 with this configuration can reduce dead zones and dead angles of the internal fluid.

[0052] In some embodiments of this microchannel, the curvature radii of multiple curved pipes 12 are all the same, wherein the curvature radius of the curved pipe 12 is the curvature radius of the extended direction of the curved pipe 12. This configuration can also reduce the dead zones and dead angles of the internal fluid.

[0053] In some embodiments of this microchannel, the radius of curvature of the curved conduit 12 is 1.4 to 3 times the radius of the cross-section to enhance fluid turbulence, thereby improving the mixing, mass transfer and heat transfer within the fluid.

[0054] In some embodiments of this microchannel, the reaction microchannel includes an inlet pipe 2 and an outlet pipe (not shown in the figure). In the embodiment shown, the inlet pipe 2 has two material inlets 20 to facilitate the simulation of mixing two fluid streams. Of course, in other suitable embodiments, the number of material inlets 20 can be one, three, or more. The inlet pipe 2 is connected to the first straight pipe of the microchannel unit located at the microchannel inlet, and the outlet pipe is connected to the eighth curved pipe of the microchannel unit located at the microchannel outlet.

[0055] On the other hand, according to some embodiments of this application, a microreactor is also provided. Figure 3 A three-dimensional schematic diagram of a microreactor according to some embodiments of this application is shown. It includes reaction microchannels and heat exchange microchannels, the reaction microchannels employing the configuration of microchannel 100 as described in the preceding one or more embodiments.

[0056] The reaction microchannel consists of multiple microchannel units 1 connected in series in the same plane. The heat exchange microchannel includes a first pipe group 101 and a second pipe group 102 that are connected. The first and second pipe groups are arranged in different planes and separated from each other by a distance. The reaction microchannel 100 is sandwiched between the first and second pipe groups. In the orthographic projection seen in the height direction of the microreactor, the reaction microchannel is covered by the heat exchange microchannel, so that the heat exchange microchannel is located above and below the reaction microchannel and can cover the entire reaction microchannel area. This microreactor can be scaled up by connecting microreactors in series or in parallel, increasing the flux, etc., making it suitable for industrial scale-up and ensuring the needs of industrial production.

[0057] According to some embodiments of this microreactor, the pipes in the microchannel 100 and / or the first pipe group 101 and / or the second pipe group 102 are respectively extended in a meandering direction, thereby forming a longer reaction path in a limited space.

[0058] According to some embodiments of this microreactor, the cross-section of the pipes constituting the first pipe group 101 and / or the second pipe group 102 is rectangular, with a width of 3 mm to 5 mm and a height of 1 mm to 3 mm.

[0059] According to some embodiments of this microreactor, such as Figure 3 As shown, the inlet of the reaction microchannel and the inlet 1030 of the heat exchange microchannel are respectively located at opposite corners of the microreactor.

[0060] The following examples 1-3 further illustrate the advanced effects of this microreactor and its microchannels:

[0061] Example 1: Three-dimensional serpentine curved circular cross-section microchannel

[0062] Adopting such Figure 1 The microchannel shown in the experiment comprises three microchannel units 1 and one inlet conduit 2. Each microchannel unit 1 contains eight interconnected straight conduits 11 and eight 90-degree curved conduits 12. In this embodiment, the longitudinal section of the microchannel is a circular cross-section with a constant radius of 0.25 mm. All straight conduits 11 are 1 mm long, and all 90-degree curved conduits 12 have a radius of curvature of 0.75 mm. The inlet conduit 2 contains two inlets, one for each of two different materials. The total volume of the three-dimensional serpentine microchannel in this embodiment is 10.8 μL. The velocity vector diagram on the longitudinal section of the channel was obtained through computational fluid dynamics simulation, as shown below. Figure 4 As shown, two symmetrical vortices, known as Dean vortices, form on the longitudinal section of the channel, thereby enhancing mass and heat transfer processes in the radial direction. Further computational fluid dynamics simulations reveal... Figure 1The microchannel shown was continuously fed with fluids of the same flow rate and properties as water at 25 degrees Celsius at the two inlets. The mixing index at different volume positions within the microchannel used in this embodiment was obtained at different flow rates, as shown in Table 1. It can be seen that within the studied flow rate range, i.e., 0.248-0.99 ml / min, the mixing index at the outlet of the microchannel used in this embodiment is 1, meaning that the material is completely mixed at the outlet. Furthermore, a good mixing index is also observed at the 1 / 4 volume position of the microchannel. This indicates that the microchannel of this embodiment can achieve complete mixing of materials within 0.65 s, demonstrating excellent mixing performance. It is understood that a higher mixing index in the table indicates better mixing performance. The volume position of the microchannel refers to the ratio of the volume of fluid flowing and filling that position to the volume of fluid used to fill the microchannel.

[0063] Table 1

[0064]

[0065] Example 2: Three-dimensional serpentine curved circular cross-section microchannel reactor

[0066] like Figure 3 As shown, the microreactor in this embodiment includes reaction microchannels and heat exchange microchannels. The reaction microchannels are three-dimensional serpentine curved circular cross-section microchannels, consisting of ten interconnected rows of microchannels. Each row of microchannels contains 12 microchannel units, and each microchannel unit 1 contains 8 interconnected straight tubes 11 and 8 90-degree curved tubes 12. In this embodiment, the longitudinal cross-section of each microchannel unit 1 is a circular cross-section with a constant radius of 0.5 mm, all straight tubes 11 are 1 mm long, and all 90-degree curved tubes 12 have a radius of curvature of 1 mm. In this embodiment of the microchannel reactor, adjacent rows of microchannels are connected by three-dimensional curved channels. The three-dimensional curved tubes used for connecting rows include 5 straight tubes and 4 90-degree curved tubes. In this embodiment of the microchannel reactor, the volume of the reaction microchannels is 2 ml. In this embodiment of the microreactor, the heat exchange channel is divided into upper and lower layers, located above and below the reaction channel respectively, 1 mm away from the reaction channel. The upper and lower layers are connected by a straight pipe with a circular cross-section and a radius of 1.25 mm. The longitudinal cross-section of the heat exchange microchannel is rectangular, with a channel width of 5 mm and a height of 1 mm. A three-dimensional serpentine curved circular cross-section microchannel reactor made of glass is obtained using ultrafast laser technology.

[0067] The mass transfer coefficient was determined using a chemical absorption method. CO2 and Na2CO3 solutions contacted, dispersed, and underwent mass transfer in the microreactor. The mass transfer performance of the microreactor in this embodiment and existing microreactors was compared under different gas-liquid two-phase flow ratios. The results are as follows: Figure 5As shown, it should be noted that the gas phase flow rate was always maintained at 60 mL / min, and the gas-liquid two-phase flow ratio was changed by altering the liquid flow rate. Experimental results show that, under the experimental conditions, the mass transfer coefficient of the microreactor of this invention is higher than that of existing microreactors, indicating that the three-dimensional curved circular cross-section microchannel of this invention has excellent mass transfer performance.

[0068] The heat transfer coefficient was determined using a counter-current heat exchange method. The cold fluid flowed through the reaction microchannel at a flow rate of 30 mL / min, while the hot fluid flowed through the heat exchange microchannel and was transported via a circulating water bath at a temperature of 80 degrees Celsius. The measured heat transfer coefficient of this microreactor was 476.6 W / m² / °C, significantly higher than the 150.8 W / m² / °C of a microreactor from a certain company, indicating that the microchannel reactor of this invention possesses excellent heat transfer performance.

[0069] Example 3: Zidovudine hydroxyl protection reaction

[0070] A small amount of pyridine was added to β-thymidine (1.817 g) and triphenylchloromethane (6.273 g), and the mixture was then placed in an ultrasonic cleaner to promote rapid dissolution of the solid until the solution was clear and transparent. The solution was then poured into a 20 mL volumetric flask and brought to volume to obtain the reaction feed solution. The feed solution was delivered using a syringe pump at a flow rate of 0.033 mL / min into the reaction microchannel of the microreactor in Example 2. A back pressure valve was connected to the outlet of the reaction channel, with a pressure of approximately 0.52 MPa. A circulating oil bath was used to deliver the heat exchange fluid (silicone oil) at an inlet temperature of 100°C into the heat exchange microchannel of the microreactor in Example 2. After the system reached steady state, the reaction effluent was collected, and the reaction yield was determined to be 98.6% by HPLC analysis. Under the same experimental conditions, a zidovudine hydroxyl protection reaction was carried out using a capillary microchannel reactor with an inner diameter of 0.5 mm and a total volume of 2 mL, yielding a reaction yield of 93.2%. A comparison of the reaction results in the two microreactors shows that the microchannel reactor of the present invention has excellent reaction performance.

[0071] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0072] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0073] It should be understood that the two directions mentioned in the text, such as "perpendicular", "consistent", and "parallel", do not need to meet strict mathematical angle requirements, but are allowed a certain tolerance range. For example, the difference from the mathematically required angle is within 5°. "Along" a certain direction means that there is at least a component in that direction. Preferably, the angle with that direction is within 10°, and more preferably, the angle is within 5°.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A microchannel for use in a microreactor, characterized in that, It comprises multiple microchannel units connected in series, each of the microchannel units comprising: Multiple straight conduits, each extending in a straight line, with a length of 0.5 mm to 5 mm; and Multiple curved pipes extend along curves and connect adjacent straight pipes. The extension directions of the two adjacent straight pipes are at a 90° angle, which causes the extension direction of the microchannel unit to turn 90 degrees continuously in three-dimensional space. This allows the straight pipes to be laid out along a first direction, a second direction, and a third direction in three-dimensional space, wherein the first direction is perpendicular to the third direction, and the second direction is perpendicular to the plane containing the first direction and the third direction. Wherein, the cross-section of the microchannel at any position is circular, the radius of the cross-section is 0.05 mm to 2.5 mm, and the cross-sectional area of ​​the microchannel at any position remains unchanged; the curvature radius of the multiple curved pipes is the same; the curvature radius of the curved pipe is 1.4 to 3 times the cross-sectional radius.

2. The microchannel as described in claim 1, characterized in that, Each of the microchannel units has the same configuration.

3. The microchannel as described in claim 2, characterized in that, The straight conduit includes a first straight conduit, a second straight conduit, a third straight conduit, a fourth straight conduit, a fifth straight conduit, a sixth straight conduit, a seventh straight conduit, and an eighth straight conduit; the curved conduit includes a first curved conduit, a second curved conduit, a third curved conduit, a fourth curved conduit, a fifth curved conduit, a sixth curved conduit, a seventh curved conduit, and an eighth curved conduit. Wherein, the first curved tube connects the first straight tube and the second straight tube, the first straight tube in the connected state is arranged along the first direction, and the second straight tube is arranged from the first curved tube along the negative direction of the second direction; The second curved tube connects the second straight tube and the third straight tube, and the third straight tube in the connected state is arranged along the negative direction of the first direction; The third curved tube connects the third straight tube and the fourth straight tube, and the fourth straight tube is arranged along the third direction in the connected state; The fourth curved tube connects the fourth straight tube and the fifth straight tube, and the fifth straight tube is arranged along the first direction in the connected state; The fifth curved tube connects the fifth straight tube and the sixth straight tube, and the sixth straight tube is arranged along the positive direction of the second direction in the connected state; The sixth curved tube connects the sixth straight tube and the seventh straight tube, and the seventh straight tube in the connected state is arranged along the negative direction of the first direction; The seventh curved tube connects the seventh straight tube and the eighth straight tube, and the eighth straight tube is arranged along the third direction in the connected state; The eighth curved tube connects the eighth straight tube to the first straight tube of the adjacent microchannel unit, and the first straight tube of the adjacent microchannel unit is arranged along the first direction in the connected state.

4. The microchannel as described in claim 1, characterized in that, The multiple straight pipes are of the same length.

5. The microchannel as described in claim 1, characterized in that, Including inlet and outlet pipelines; The inlet pipe is connected to the first straight pipe of the microchannel unit located at the microchannel inlet, and the outlet pipe is connected to the eighth curved pipe of the microchannel unit located at the microchannel outlet.

6. A microreactor, characterized in that, It includes reaction microchannels and heat exchange microchannels, wherein the reaction microchannels are microchannels as described in any one of claims 1 to 5; The reaction microchannel is composed of multiple microchannel units connected in series in the same plane; The heat exchange microchannel includes a first pipeline group and a second pipeline group that are connected to each other. The first pipeline group and the second pipeline group are respectively arranged in different planes and separated from each other by a distance. The reaction microchannel is sandwiched between the first pipeline group and the second pipeline group. In the orthographic projection seen in the height direction of the microreactor, the reaction microchannel is covered by the heat exchange microchannel.

7. The microreactor as described in claim 6, characterized in that, The cross-section of the pipes constituting the first pipe group and / or the second pipe group is rectangular, the width of the rectangle is 3 mm to 5 mm, and the height of the rectangle is 1 mm to 3 mm.

8. The microreactor as described in claim 6, characterized in that, The inlet of the reaction microchannel and the inlet of the heat exchange microchannel are respectively located at opposite corners of the microreactor.

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