Multi-channel microreactor and application method thereof

Abstract

The invention relates to a multi-channel micro-reactor and an application method thereof. The multi-channel micro-reactor comprises an inlet section (8), a mixing section (28), a reaction section (5) and an outlet section (3) which are communicated in sequence, a first fluid inlet (2) is formed in the bottom of the inlet section; a mixing channel (30) is arranged in the mixing section, an opening is formed in the bottom of the mixing channel, and distribution holes (11) are formed in the pipe wall of the mixing channel; a reaction channel (6) and a heat exchange channel are arranged in the reaction section, the bottom of the reaction channel is communicated with the mixing channel through a first pore plate (18), and the heat exchange channel is provided with a heat exchange medium inlet (12) and a heat exchange medium outlet (13); the outlet section is provided with a top outlet (1), the bottom of the outlet section is communicated with the reaction channels through a second pore plate (4), and the outlet section is used for collecting materials in the plurality of reaction channels. The multi-channel microreactor provided by the invention can be used for continuous reaction processes of gas-liquid, liquid-liquid, gas-liquid-liquid or gas-liquid-solid and other multi-phase systems.

Description

Technical Field

[0001] The present invention relates to a multi-channel microreactor device and an application method thereof, and more specifically, to a reactor suitable for continuous reactions in gas-liquid, liquid-liquid, gas-liquid-liquid and gas-liquid-solid systems. Background Art

[0002] Microreactor technology is an important process intensification technology, which has the characteristics of small size, large specific surface area, high efficiency and inherent safety. Using a microreactor can eliminate the mass transfer or heat transfer resistance in the reaction process and improve the reaction efficiency. In practical applications, microreactors mostly use a tubular channel structure to provide a reaction space, and the amplification of the reactor generally adopts a mode of amplifying the number of multi-channel parallel. The main problem to be solved in the industrial application of multi-channel microreactors is how to evenly distribute the fluid to ensure that the flow and reaction states in each channel are consistent and avoid the occurrence of non-ideal states such as fluid short-circuit or uneven distribution. And the actual reaction process mostly involves multi-phase flow reaction systems such as gas-liquid, liquid-liquid, gas-liquid-liquid or gas-liquid-solid, so it is very important for multi-channel microreactors to achieve uniform distribution of fluids in multi-phase flow systems.

[0003] CN217189486U provides a multi-channel microreactor for manufacturing micro-droplets. A sleeve structure is formed in each channel. The continuous phase enters the channel through the annular gap flow channel formed between the injection tube and the channel, and the dispersed phase enters the channel through the built-in injection tube and forms droplets under the action of the continuous phase. The distribution of fluid in the multi-channel adopts a multi-way distribution pipe, that is, the fluid enters through the inlet into a distribution pipe connected to each channel and then enters each flow channel.

[0004] CN102600779A provides a multi-channel reactor with a heat exchange function, which consists of a bundle of multi heat exchange tubes. A hydraulic cavitation element is provided at the top of the heat exchange tube to realize the mixing of liquid-liquid two phases and enhance the heat transfer performance of the fluid in the tube.

[0005] It can be found from the existing literature that when multi-channel microreactors are applied to multi-phase flow reaction systems, the research on the uniformity of fluid distribution in each channel mostly focuses on the laboratory scale, and the multi-channel fluid distribution structure is mostly a simple plate-type branch structure, which is difficult to ensure uniform fluid distribution. In addition, in actual industrial applications, the reaction process often has obvious heat exchange, so the heat exchange function of multi-channel microreactors needs to be considered. Therefore, a multi-channel microreactor that conforms to the actual situation of industrial applications should have the function of evenly distributing multi-phase flow fluids and being able to exchange heat in a timely manner. Summary of the Invention

[0006] One of the technical problems to be solved by the present invention is to provide a multi-channel microreactor suitable for multi-phase flow reaction systems such as gas-liquid, liquid-liquid, gas-liquid-liquid and gas-liquid-solid and having a heat exchange function on the basis of the existing technology.

[0007] In a first aspect, the present invention provides a multi-channel microreactor, which includes an inlet section 28, a mixing section 28, a reaction section 5, and an outlet section 3 that are sequentially connected from bottom to top; wherein:

[0008] A first fluid inlet 2 is provided at the bottom of the inlet section.

[0009] A mixing channel 30 is provided in the mixing section. The bottom of the mixing channel is open, and distribution holes 11 are provided on the tube wall of the mixing channel.

[0010] A reaction channel 6 and a heat exchange channel are provided in the reaction section. The bottom of the reaction channel communicates with the mixing channel through a first orifice plate 18. The heat exchange channel is provided with a heat exchange medium inlet 12, a heat exchange medium outlet 13, and a heat exchange medium discharge pipe 15.

[0011] An outlet 1 is provided at the top of the outlet section, and the bottom communicates with the reaction channel through a second orifice plate 4. The outlet section is used to collect the materials in multiple reaction channels.

[0012] In the present invention, optionally, the inlet section is an inverted conical cylinder; preferably, the cone angle of the inverted conical cylinder is 20 to 150°.

[0013] Preferably, a conical dispersion member is provided in the inlet section. The dispersion member is coaxial with the inlet section, and the distance between the bottom of the dispersion member and the bottom of the inlet section is 10 to 150 mm.

[0014] Preferably, a heat exchange pipeline is provided in the inlet section, and the heat exchange pipeline serves as a heat exchange medium channel.

[0015] Preferably, a uniform distribution plate is provided at the bottom of the mixing section, and the fluid in the inlet section is distributed by the uniform distribution plate and then enters the mixing section.

[0016] Preferably, a baffle is provided below the mixing channel, and the distance between the baffle and the bottom of the mixing channel is 5 to 50 mm.

[0017] Preferably, the cross-sectional area of the mixing channel is 0.1 to 65 mm 2 , the length is 10 to 500 mm, and more preferably 15 to 150 mm.

[0018] Preferably, the diameter of the mixing channel increases from bottom to top.

[0019] Optionally, the aperture of the distribution holes on the mixing channel is 0.3 to 5 mm, and the center distance between two adjacent distribution holes is 5 to 100 mm, preferably 10 to 40 mm.

[0020] Preferably, a draft tube is provided in the mixing channel. The end face of the connecting pipe extending into the draft tube is an inclined plane, and its tip is located at the top of the inclined plane.

[0021] The ratio of the cross-sectional area of the built-in draft tube in the mixing channel to the cross-sectional area of the mixing channel is 0.1 - 0.6:1. The distance from the top of the draft tube to the top of the mixing channel is 5 - 30 mm, and the distance from the bottom of the draft tube to the bottom of the mixing channel is 5 - 30 mm.

[0022] Optionally, heat exchange tubes are provided in the mixing section. A second fluid inlet is provided on the side wall of the mixing section, and the distance between the second fluid inlet and the first orifice plate is 5 - 100 mm.

[0023] Optionally, the mixing section has a shell-side heat exchange structure, and a heat exchange medium inlet and a heat exchange medium outlet are provided on the heat exchange shell.

[0024] Optionally, a third fluid inlet is provided in the inlet section.

[0025] In the present invention, there are at least two reaction channels and mixing channels. The distance between adjacent reaction channels is 1 - 50 mm, preferably 3 - 30 mm;

[0026] The ratio of the heat exchange space in the reaction section to the volume of the reaction channel is 2 - 50:1, preferably 5 - 30:1.

[0027] Preferably, internal components are provided in the reaction channel, and the internal components are used to enhance the mass transfer and heat transfer processes of the fluid.

[0028] Preferably, a plurality of baffle plates are provided in the heat exchange channel, and the distance between two adjacent baffle plates is 100 - 600 mm.

[0029] Preferably, the cross-sectional area of the reaction channel is 0.1 - 65 mm 2 , and the length is 50 - 20000 mm, preferably 100 - 6000 mm.

[0030] Preferably, the first orifice plate and / or the second orifice plate are internally provided with heat exchange pipelines.

[0031] Preferably, the height of the outlet section is less than 15 cm. Preferably, a second outlet is further provided on the side wall at the bottom of the outlet section.

[0032] Optionally, the reaction section is divided into at least two sections, and each section communicates with each other through a second orifice plate.

[0033] The multi-channel microreactor provided by the present invention can be used for reaction processes in multiphase flow systems such as gas-liquid, liquid-liquid, gas-liquid-liquid, or gas-liquid-solid.

[0034] In a second aspect, the present invention provides a method for using a multi-channel microreactor for gas-liquid reactions. The liquid enters the inlet section from the first fluid inlet, flows upward into the mixing channels in the mixing section, the gas enters the mixing section from the second fluid inlet, and enters the mixing channels through the distribution holes on the mixing channels. In the mixing channels, the liquid and the gas are mixed and flow upward through the first orifice plate into the reaction channels in the reaction section for reaction; the fluid that has completed the reaction leaves the reaction channels and enters the outlet section, and after gathering in the outlet section, it is discharged from the reactor through the outlet; the volume ratio of the introduced gas to the liquid is 0.05 to 100:1, preferably 0.1 to 40:1.

[0035] In a third aspect, the present invention provides a method for using a multi-channel microreactor for liquid-liquid reactions. The first liquid enters the inlet section from the first fluid inlet, flows upward into the mixing channels in the mixing section, the second liquid enters the mixing section of the reactor from the second fluid inlet, and the second liquid enters the mixing channels through the distribution holes on the mixing channels to be mixed with the first liquid; the mixed fluid flows upward through the first orifice plate into the reaction channels in the reaction section for reaction; the fluid that has completed the reaction leaves the reaction channels and enters the outlet section, and after gathering in the outlet section, it is discharged from the reactor through the outlet; wherein, the density of the first liquid is greater than that of the second liquid, and the volume ratio of the first liquid to the second liquid is 0.01 to 20:1, preferably 0.1 to 6:1.

[0036] When the multi-channel microreactor provided by the present invention is used in a gas-liquid-solid system, the solid can be fixed in the reaction channels in the form of a catalyst or internal components to form a bed layer, or can form a pseudo-homogeneous slurry with the liquid phase in the form of nano- or micron-sized particles and pass through the reactor.

[0037] The beneficial effects of the multi-channel microreactor and its application method provided by the present invention are as follows:

[0038] Compared with the multi-channel microreactors disclosed in the prior art, the multi-channel microreactor provided by the present invention can achieve uniform distribution of various multiphase flow reaction systems such as gas-liquid, liquid-liquid, gas-liquid-liquid, and gas-liquid-solid through special structural design, and can ensure that the residence time of the reaction fluid in each channel is as consistent as possible, avoiding the unsatisfactory reaction performance caused by the residence time distribution. The provided multi-channel microreactor has the ability of timely heat exchange, and the heat exchange space volume is much larger than the volumes of the reaction channels and the mixing channels, which can ensure that the temperature during the reaction process remains stable. The reaction channels are provided with mixing components, which can strengthen the mixing and mass transfer during the reaction process and improve the reaction performance. Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of the multi-channel microreactor provided by the present invention.

[0040] Figure 2 It is a schematic structural diagram of the inlet section and the mixing section with heat exchange function.

[0041] Figure 3 It is a schematic diagram of the structure of a mixing channel with a draft tube.

[0042] Figure 4 It is a side view of the first orifice plate with heat exchange function.

[0043] Figure 5 It is a top view of the structure of the first orifice plate with heat exchange function.

[0044] Figure 6 Schematic diagram of the heat exchange pipeline structure of the inlet section.

[0045] Figure 7 It is a schematic diagram of the structure of a multi-channel microreactor with multiple reaction sections.

[0046] Figure 8 It is a schematic diagram of the structure of the multi-channel microreactor in Comparative Example 8.

[0047] Reference numerals:

[0048] 1 - Top outlet, 2 - First fluid inlet, 3 - Outlet section

[0049] 4 - Second orifice plate, 5 - Reaction section, 6 - Reaction channel

[0050] 7 - Baffle plate, 8 - Inlet section, 9 - Dispersion member

[0051] 10 - Uniform distribution plate, 11 - Distribution holes, 14 - Second fluid inlet

[0052] 15 - Discharge pipe, 17 - Baffle, 18 - First orifice plate

[0053] 21 - Orifice plate heat exchange pipeline, 23 - Inlet section heat exchange pipeline, 26 - Connecting pipe

[0054] 27 - Draft tube, 28 - Mixing section, 29 - Mixing section heat exchange shell

[0055] 30 - Mixing channel, 31 - Reaction section shell

[0056] 12, 19, 22, 24 - Heat exchange medium inlets, 13, 16, 20, 25 - Heat exchange medium outlets Specific embodiments

[0057] The following details the specific embodiments of the present invention.

[0058] In a first aspect, the present invention provides a multi-channel microreactor, including an inlet section 28, a mixing section 28, a reaction section 5, and an outlet section 3 that are sequentially connected in communication from bottom to top; wherein:

[0059] The bottom of the inlet section is provided with a first fluid inlet 2, and the top is communicated with the mixing section;

[0060] A mixing channel 30 is arranged in the mixing section. The bottom of the mixing channel is open, and distribution holes 11 are arranged on the tube wall of the mixing channel;

[0061] A reaction channel 6 and a heat exchange channel are arranged in the reaction section. The bottom of the reaction channel is communicated with the mixing channel through a first orifice plate 18. The heat exchange channel is provided with a heat exchange medium inlet 12, a heat exchange medium outlet 13 and a heat exchange medium discharge pipe 15;

[0062] The top of the outlet section is provided with an outlet 1, and the bottom is communicated with the reaction channel through a second orifice plate 4. The outlet section is used to collect the materials in multiple reaction channels.

[0063] In the present invention, the inlet section is used to accommodate the first fluid and distribute it into the mixing channel. The inlet section can be a cylindrical shape with a smooth bottom or an inverted conical cylinder. A preferred embodiment is as shown in the attached Figure 1 figure. The inlet section 8 is an inverted conical cylinder, and the preferred cone angle is 20 to 150°. The inverted conical cylinder can make the fluid flow gradually stable and flow upward to the mixing section, and be evenly distributed into each mixing channel.

[0064] In the present invention, in a preferred embodiment, a dispersion member 9 is arranged in the inlet section 8. The dispersion member is coaxial with the inlet section and is located above the first fluid inlet. The distance between the bottom of the dispersion member and the top of the first fluid inlet is 10 to 150 mm. The dispersion member adopts a structure of a perforated plate, a porous medium or a packed particle layer, and can adopt shapes such as a conical shape and a frustum shape. The dispersion member can evenly distribute the fluid entering the inlet section from the first fluid inlet, avoid the situation that the flow rate is high at the center and low at the wall surface, so that the fluid passing through the dispersion member can flow with a relatively uniform flow rate distribution, and then enter the mixing section. <00>

[0065] In the present invention, a heat exchange pipeline is arranged or not arranged in the inlet section. In addition to the first fluid inlet at the bottom, the inlet section can also be provided with other fluid inlets. In a preferred embodiment, a heat exchange pipeline 23 is arranged in the inlet section. The heat exchange pipeline serves as a heat exchange medium channel, and the heat exchange pipeline is provided with a heat exchange medium inlet 22 and a heat exchange medium outlet 16.

[0066] In the present invention, the inlet section is communicated with the mixing section. In a preferred embodiment, a uniform distribution plate 10 is arranged at the bottom of the mixing section, and the fluid in the inlet section flows upward and is distributed by the uniform distribution plate and then enters the mixing section.

[0067] In the present invention, a plurality of mixing channels are provided in the mixing section. The bottom of the mixing channel is open, and distribution holes 11 are provided on the tube wall of the mixing channel. After the fluid enters the mixing section, it flows into the mixing channel through the distribution holes. Preferably, the cross-sectional area of the mixing channel is 0.1 - 65 mm 2 , and the length is 10 - 500 mm; in a preferred embodiment, the cross-sectional area of the mixing channel is 0.1 - 65 mm 2 , and the length is 15 - 150 mm.

[0068] A baffle 17 is provided or not provided below the open bottom of the mixing channel. In a preferred embodiment, a baffle is provided below the mixing channel, and the distance between the baffle and the open bottom of the mixing channel is 5 - 50 mm. The baffle can make the fluid entering the mixing channel more evenly distributed, avoiding the situation of high central flow velocity and low wall surface flow velocity inside the mixing channel. The baffle can be in various shapes such as circular, rectangular, perforated plate, cup-shaped, etc. or a combination of various shapes.

[0069] In the present invention, the cross-section of the mixing channel is circular or rectangular, and the diameter of the mixing channel is a straight tube or a variable-diameter cylinder that expands from bottom to top. In one embodiment, the mixing channel is a circular tube with a constant diameter.

[0070] In a preferred embodiment, the diameter of the mixing channel expands from bottom to top, and the mixing channel is a conical tube with a gradually increasing cross-sectional area. This can effectively reduce the possibility of bubble or droplet coalescence.

[0071] In a preferred embodiment, the cross-section of the mixing channel is rectangular, and the aspect ratio of length to width is 0.1 - 15:1, preferably 0.5 - 10:1. The rectangular channel can reduce the characteristic size of the mass transfer or heat transfer process to improve the corresponding mass transfer or heat transfer performance.

[0072] During the application of the multi-channel microreactor of the present invention, there is a phenomenon of fluid stratification inside the mixing section. The fluid distribution from top to bottom is gas and liquid in sequence, or it can also be gas, a liquid with a smaller density, and a liquid with a larger density.

[0073] In the mixing section, the aperture of the distribution holes provided on the mixing channel is 0.3 - 5 mm, preferably 0.5 - 1.5 mm, and the center distance between two adjacent distribution holes is 5 - 100 mm, preferably 10 - 40 mm.

[0074] In a preferred embodiment, a guide cylinder is arranged inside the mixing channel. The ratio of the cross-sectional area of the guide cylinder to that of the mixing channel is 0.1 - 0.6:1. The top of the guide cylinder is 5 - 30 mm away from the top of the mixing channel, and the bottom of the guide cylinder is 5 - 30 mm away from the bottom of the mixing channel.

[0075] The connecting pipe 26 is inserted into the draft tube through the distribution holes 11, and the fluid to be mixed is introduced into the draft tube through the connecting pipe 26. Through the special structures of the distribution holes and the draft tube, the mixing channel can introduce dispersed-phase fluids such as gas, liquid or gas-liquid mixture into the interior of the mixing channel, and mix with the continuous-phase fluid entering the mixing channel from the bottom. The dispersed-phase fluid entering the mixing channel through the connecting pipe is dispersed into bubbles or droplets by the continuous-phase fluid moving upward inside the mixing channel and then continues to move upward.

[0076] Preferably, the end face of the connecting pipe extending into the draft tube inside the mixing channel is an inclined plane, similar to the shape of a syringe needle, with its tip located at the upper part, which is beneficial to generating bubbles or droplets with smaller diameters to promote the mixing of the dispersed-phase fluid and the continuous-phase fluid. Since the fluid passing through the connecting pipe has a smaller density, two regions with different densities are formed inside the mixing channel. The fluid inside the draft tube contains a large number of bubbles or droplets, so its density is smaller, while the space between the draft tube and the wall of the mixing channel is mainly continuous-phase fluid, so its density is larger. Due to the obvious density difference between the fluids contained in the inner and outer spaces of the draft tube in the mixing channel, a circulation is formed, with the fluid inside the draft tube moving upward and the fluid outside the draft tube moving downward. The circulation speed inside the mixing channel is relatively high, so it can have a stronger shearing effect on the dispersed-phase fluid flowing in through the connecting pipe, and the generated bubbles or droplets have smaller sizes and better mixing effect with the continuous-phase fluid. At this time, due to the relatively high flow velocity of the fluid, the coalescence between bubbles and droplets can be inhibited, and the mixing between the dispersed-phase and continuous-phase fluids can be strengthened. In addition, the mixing channel can preferably be a conical pipe with a gradually expanding cross-sectional area at the top, which can further reduce the possibility of coalescence of bubbles or droplets and maintain the highly dispersed state of the dispersed phase.

[0077] In the present invention, a second fluid inlet is provided on the sidewall of the inlet section or the sidewall of the mixing section. The position of the second fluid inlet can be set accordingly according to the structure of the mixing section. If the reaction system involved does not react under normal temperature or lower temperature conditions, there is no need to provide a heat exchange shell layer in the mixing section, and the second fluid inlet is provided on the sidewall of the mixing section, and the distance from the orifice plate above it is 5 to 100 mm. If the reaction system involved can react under normal temperature or lower temperature conditions, the second fluid inlet is preferably provided on the sidewall of the inlet section. In this case, the second fluid inlet can still be provided on the sidewall of the mixing section. In one embodiment, the second fluid inlet is provided at the top of the mixing section and is more than 5 mm above the phase interface in the mixing section. Since the inlet section and the mixing section are relatively large in volume, if the two fluids come into direct contact in the non-mixing channels in the inlet section or the mixing section and react, problems such as insufficient mixing, poor reaction effect, and serious fluid backmixing will occur, and the advantages of the microreactor in enhancing the mixing and reaction processes cannot be exerted. Therefore, with the above special structural design of the fluid inlet, the two fluids that can react do not mix and react as much as possible before entering the mixing channel. Since there is still a certain degree of contact between the two fluids in the mixing section, in order to avoid temperature rise caused by the reaction heat effect, the inlet section, the mixing section and the orifice plate of the reactor can all have heat exchange functions. Heat exchange pipelines can be provided inside the inlet section, and heat exchange pipelines can also be provided on the orifice plate. A heat exchange shell layer can be provided in the mixing section. Through the heat exchange function settings at the above three places, heat exchange can be carried out in a timely manner to maintain the stability of the reaction temperature.

[0078] In the present invention, the mixing channels in the mixing section communicate with the reaction channels in the reaction section one by one. The cross-sectional areas of the mixing channels and the reaction channels are the same. In the reaction section, the cross-sectional area of the reaction channel is 0.1 to 65 mm 2 , and the cross-sectional shape of the reaction channel can be rectangular or circular. In the present invention, the length of the reaction channel is 50 to 20,000 mm, preferably 100 to 6,000 mm. The distance between two adjacent reaction channels is 1 to 50 mm, preferably 3 to 30 mm.

[0079] In the present invention, the reaction channel is an empty tube, and internal components or a particle bed layer can be provided inside. In one embodiment, plate-shaped, porous, granular, corrugated or grid-shaped internal components are provided in the reaction channel, or a combination of the above various shapes. Providing internal components can strengthen the mixing, mass transfer and heat transfer processes of the fluid inside the reaction channel, promote the progress of the reaction process, and timely transfer the heat to the channel wall surface and exchange heat with the heat exchange medium inside the shell layer of the reaction section to maintain the stability of the reaction temperature. In addition, a catalyst bed layer can be filled inside the reaction channel to have the catalytic function of the catalyst and accelerate the progress of the reaction process.

[0080] In the present invention, the outlet section is provided with at least one outlet. In one embodiment, the outlet is provided at the top of the outlet section, and the first fluid and the second fluid after the reaction are discharged from the reactor together through the top outlet. In one embodiment, the outlet is provided at the top of the outlet section, and a second outlet is provided on the bottom side wall of the outlet section. The top outlet and the second outlet discharge different fluids respectively. At this time, the multiphase flow fluid is phase-separated inside the outlet section. The top outlet is located above the phase interface and mainly discharges gas or the light phase, while the second outlet is located below the phase interface and mainly discharges liquid or the heavy phase. By adopting two outlets and utilizing the fluid phase separation, the function of the separation device is integrated, and the problem of excessive reaction caused by too long contact time of the multiphase flow fluid can be avoided.

[0081] The multi-channel microreactor provided by the present invention can be used for the reaction processes of multiphase flow systems such as gas-liquid, liquid-liquid, gas-liquid-liquid or gas-liquid-solid. When used in a gas-liquid-solid system, the solid can be fixed in the reaction channel in the form of a catalyst or an internal component to form a bed layer, or can form a pseudo-homogeneous slurry with the liquid phase in the form of nano- or micron-sized particles and pass through the reactor. It can be understood that when used in a gas-liquid-liquid or gas-liquid-solid system, the above gas-liquid volume ratio and liquid-liquid volume ratio are still applicable.

[0082] The multi-channel microreactor provided by the present invention is preferably placed vertically, which is beneficial to the uniform distribution of bubbles or droplets formed in the multiphase flow system in each channel.

[0083] According to the characteristics of the actual reaction, the reaction section can be set in one or more series-connected sections. The orifice plate connecting two adjacent reaction sections can be provided with a heat exchange function to conduct heat exchange in a timely manner. The series-connected reaction sections can be separately introduced with a heat exchange medium, and different reaction sections can have different reaction temperatures for the purpose of further enhancing the reaction performance. It is also possible for the same heat exchange medium to pass through the multi-section reaction sections in sequence. The fluid flowing out of the reaction channel enters the outlet section and is discharged from the reactor through the outlet. The length of the outlet section is short, which can suppress the undesirable flow conditions such as the deflection and vortex of the multiphase flow fluid, and can also shorten the residence time of the fluid as much as possible.

[0084] In the second aspect, a method for gas-liquid reaction using the multi-channel microreactor provided by the present invention is as follows: The liquid enters the inlet section from the first fluid inlet, flows upward into the mixing channel of the mixing section, the gas enters the mixing section from the second fluid inlet, enters the mixing channel through the distribution holes on the mixing channel, and in the mixing channel, the liquid and the gas are mixed and flow upward through the first orifice plate into the reaction channel of the reaction section for reaction; the fluid that has completed the reaction leaves the reaction channel and enters the outlet section, and after being collected in the outlet section, it is discharged from the reactor through the outlet; the volume ratio of the introduced gas to the liquid is 0.05-100:1, preferably 0.1-40:1.

[0085] In a third aspect, the present invention provides a method for using a multi-channel microreactor for liquid-liquid reactions. The first liquid enters the inlet section through the first fluid inlet and flows upward into the mixing channels in the mixing section. The second liquid enters the mixing section of the reactor through the second fluid inlet. The second liquid enters the mixing channels through the distribution holes on the mixing channels and mixes with the first liquid. The mixed fluid flows upward through the first orifice plate and enters the reaction channels in the reaction section for reaction. The fluid that has completed the reaction leaves the reaction channels and enters the outlet section, where it converges and is discharged from the reactor through the outlet. Among them, the density of the first liquid is greater than that of the second liquid, and the volume ratio of the first liquid to the second liquid is 0.01 to 20:1, preferably 0.1 to 6:1.

[0086] In the specific implementation process, the first fluid and the second fluid enter the reactor from the lower part of the reactor. If the two fluids react immediately after mixing and have a significant heat effect, in order to avoid premature mixing of the reactants in the space of the non-mixing channels in the inlet section or the mixing section, resulting in an unsatisfactory reaction effect, the two fluids should enter the reactor separately. There is at least one phase interface in the mixing section, which can be a gas-liquid phase interface, a liquid-liquid phase interface, or both phase interfaces coexist. The first fluid mainly enters the liquid phase or heavy phase space at the lower part of the mixing section from the inlet section, passes through the baffle, and enters the mixing channels from the bottom of the mixing channels. The top of the inlet of the second fluid should be immersed in the gas phase or light phase space at the upper part of the mixing section and enters the mixing channels through the distribution holes via the connecting pipe. Inside the mixing channels, the second fluid as the dispersed phase is dispersed into bubbles or droplets by the first fluid as the continuous phase and is thoroughly mixed with the first fluid, and then moves upward into the reaction channels. Since the length of the mixing channels is short and the heat effect is not significant, it has little impact on the overall reaction result. Heat exchange functions can be added at three places, namely the inlet section, the mixing section, and the orifice plate, to ensure that the temperature of the two fluids remains stable after mixing. The fluid entering the reaction channels continues to move upward and reacts fully. Internal components that promote fluid mixing can be provided inside the reaction channels to strengthen the mixing, mass transfer, and heat transfer processes. In addition, a bed layer with catalyst function can be provided inside the reaction channels to catalyze the reaction process. A heat exchange shell layer is provided in the reaction section, thereby forming a tube side for the reaction and a shell side for heat exchange. Preferably, baffle plates are provided inside the shell side to strengthen the heat exchange process and maintain the reaction temperature stable. A discharge pipe is provided at the bottom of the reaction section to drain the heat exchange medium when the reactor is shut down.

[0087] If the two fluids do not react immediately after mixing, the first fluid and the second fluid can enter the reactor in parallel flow from the reactor inlet, or the inlet structures of the two fluids can be arranged in the manner of the previous paragraph. At this time, the heat exchange functions of the inlet section, the mixing section, and the orifice plate can preheat the fluids or the heat exchange functions are not used.

[0088] The gas-liquid mixed fluid in the outlet section can flow out from the outlet at the top. When there is a second outlet at the bottom of the side wall of the outlet section, the gas mainly flows out from the outlet at the top of the outlet section, while the liquid mainly flows out from the second outlet on the side wall.

[0089] The multi-channel microreactor provided by the present invention, when used in the continuous reaction process of multiphase flow fluids such as gas-liquid, liquid-liquid, gas-liquid-liquid or gas-liquid-solid, through special structural design, can achieve the uniform distribution of fluids, especially the dispersed phase bubbles and droplets, and ensure the consistency of the reaction process inside each channel. The multi-channel microreactor provided by the present invention can be used in reaction processes such as hydrogenation, oxidation or other reactions involving the continuous synthesis of fine chemicals and additives in multiphase flow.

[0090] The following specifically describes the specific embodiments of the present invention in conjunction with the accompanying drawings. However, the present invention is not limited thereby.

[0091] Figure 1 It is a schematic structural diagram of the multi-channel microreactor provided by the present invention. As shown in the appendix Figure 1 As shown, the multi-channel microreactor includes an inlet section 8, a mixing section 28, a reaction section 5 and an outlet section 3 that are sequentially connected from bottom to top. Among them, a first fluid inlet 2 is provided at the bottom of the inlet section 8, a dispersion member 9 is provided above the first fluid inlet, and a heat exchange pipeline 23 is also provided inside the inlet section. Attached Figure 6 is a top view of the heat exchange pipeline in the inlet section. It can be seen from the appendix Figure 6 that the inlet section heat exchange pipeline 23 has a heat exchange medium inlet 22 and a heat exchange medium outlet 16. A mixing channel 30 is provided in the mixing section 28, the bottom of the mixing channel is open, and distribution holes 11 are provided on the wall of the mixing channel; a uniform distribution plate 10 is provided at the bottom of the mixing section 28, and the fluid from the inlet section is distributed by the uniform distribution plate and then enters the mixing section. A baffle 17 is provided below the open bottom of the mixing channel.

[0092] A plurality of reaction channels 6 and heat exchange channels are provided in the reaction section 5. The reaction channels communicate with the mixing channels and correspond one by one. The bottom of the reaction channels communicates with the mixing channels through a first orifice plate 18. Baffle plates 7 are provided in the heat exchange channels, and the heat exchange channels are provided with a heat exchange medium inlet 12 and a heat exchange medium outlet 13. A top outlet 1 is provided at the top of the outlet section 3, and the bottom communicates with the reaction channels through a second orifice plate 4. The outlet section is used to collect the materials in multiple reaction channels.

[0093] Attached Figure 2 is a schematic structural diagram of the mixing section with heat exchange function and the inlet section. As shown in the appendix Figure 2 As shown, a heat exchange pipeline 22 can be provided inside the inlet section 8, and a heat exchange shell layer 29 is provided in the mixing section 28, and a heat exchange medium is introduced into the heat exchange shell layer.

[0094] Attached Figure 3Schematic structural diagram of an implementation manner of a mixing channel. As shown in the appendix Figure 3 As shown, a draft tube 27 is built inside the mixing channel 6, and the connecting pipe 26 extends into the draft tube 27 inside the mixing channel 6. One end of the connecting pipe 26 inside the draft tube is beveled, with a shape similar to that of a syringe needle tip, and its tip is located at the upper part.

[0095] Appendix Figure 4 、 5 Side view and top view of an orifice plate with heat exchange function. Heat exchange pipelines 21 are arranged inside the orifice plate 18, and the heat exchange pipelines have a heat exchange medium inlet 19 and a heat exchange medium outlet 19. Through the heat exchange function settings at the above three places, heat exchange can be carried out in a timely manner to maintain the stability of the reaction temperature.

[0096] Appendix Figure 7 Schematic structural diagram of a multi-channel microreactor with multiple reaction sections. As shown in the appendix Figure 7 As shown, the reaction section 5 is at least one section, and can also be multiple sections in series. Each section is connected by a second orifice plate 4. The temperatures of different reaction sections can be the same or different. Each reaction section can be separately introduced with a heat exchange medium, or the same heat exchange medium can be introduced in series. Since the actual reaction process is relatively complex, different reaction temperatures often need to be set at different stages of the reaction to improve the overall reaction performance. Therefore, when setting multiple reaction sections, the temperature of different reaction sections can be controlled according to the actual reaction characteristics. The specific method is to separately introduce the heat exchange medium into different reaction sections without sharing the same heat exchange medium. It is also possible to use the same heat exchange medium to sequentially pass through the shell sides of each reaction section in sequence.

[0097] The application method of the multi-channel microreactor provided by the present invention is that a liquid, slurry or gas-liquid mixture is introduced into the first fluid inlet, preferably a liquid or slurry, and a gas, liquid, slurry or gas-liquid mixture is introduced into the second fluid inlet 14. Preferably, a gas is introduced into the second fluid inlet 14. In an ideal situation for the two fluids, they are mixed inside the mixing channel 30. The first fluid as the continuous phase disperses the second fluid as the dispersed phase into a highly dispersed system such as bubbles or droplets to increase the interfacial specific surface area and strengthen the mass transfer and reaction process.

[0098] At the place where the mixing section 28 is connected to the inlet section 8, that is, at the bottom of the mixing section), a uniform distribution member 10 is provided, and its form can be a perforated plate, porous medium, corrugated packing, grid packing, and particle bed layer, or a combination of the above various forms. The uniform distribution member 10 can further uniformly distribute the fluid flowing from the inlet section 8 into the mixing section 28 to avoid the phenomenon of uneven distribution of the continuous phase fluid in different mixing channels.

[0099] The reaction section 5 is of a shell-and-tube structure and has a heat exchange function. The space between the shell layer 31 and the reaction channel 6 is the shell side of the multi-channel microreactor, where a heat exchange medium can be introduced to exchange heat in a timely manner and maintain the stability of the reaction temperature. At least one baffle 7 is provided in the shell side to enhance the turbulence and heat transfer performance of the heat exchange fluid in the shell side. The distance between two adjacent baffles is 100 - 600 mm. In order to fully conduct heat exchange in the reaction section 5, the volume ratio of the shell side heat exchange space of the reaction section 5 to the volume of the reaction channel 6 is 2 - 50:1, preferably 5 - 30:1. The volume of the shell side space is greater than or significantly greater than the volume of the reaction channel space, which is beneficial to maintaining the temperature stability of the reactor using the heat exchange medium. At the bottom of the heat exchange shell layer 31 of the reaction section 5, a discharge pipe 15 is provided. When the reactor stops running, it is convenient to empty the heat exchange medium in the shell side in a timely manner.

[0100] The specific embodiments of the present invention are further described above in conjunction with the accompanying drawings. However, the present invention is not limited thereby. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0101] The implementation method of the present invention is further described below through examples, but the present invention is not limited thereby.

[0102] Example 1

[0103] A multi-channel microreactor as shown in the attached Figure 1 drawings is used. The microreactor contains 108 reaction channels. The cross-section of each channel is rectangular, with a cross-sectional area of 54 mm 2 . The length of the mixing channel is 100 mm, and the length of the reaction channel is 1200 mm. One distribution hole is opened on each mixing channel, and the inner diameter of the connecting pipe passing through the distribution hole is 1 mm. The first fluid inlet is at the bottom of the reactor, and the second fluid inlet is located at the upper part of the mixing section. The operating conditions are normal temperature and pressure. The local gas holdup at the outlet of each reaction channel is measured using a conductivity probe. The first fluid is water with a flow rate of 1 m 3 / h, and the second fluid is air with a flow rate of 4 m 3 / h. After detection, the local gas holdups at the outlets of different channels are basically the same, with an average value of 0.0303. The non-uniformity of the local gas holdup distribution detected in each reaction channel is only 0.09, indicating that the fluid, especially the gas, can be evenly distributed in the multi-channel microreactor. In addition, the average gas holdup of the reactor is detected by the volume displacement method to be 0.0308, which is basically the same as the data detected by the probe method used, indicating that the data detected by the conductivity probe used is accurate and reliable.

[0104] Example 2

[0105] A multi-channel microreactor similar to that in Example 1 is adopted, with the difference that the second fluid inlet is arranged in the inlet section. The first fluid and the second fluid enter the inlet section. The microreactor contains 8 reaction channels, each channel having a rectangular cross-section with a cross-sectional area of 18 mm 2 , the mixing channel is 60 mm long, and the reaction channel is 300 mm long. Each mixing channel is provided with a distribution hole, and the inner diameter of the connecting pipe passing through the distribution hole is 1 mm. The length of the outlet section is 100 mm. The operating conditions are normal temperature and pressure, and the sampling method is used to detect the liquid volume at the outlet of each reaction channel. The first fluid is water with a flow rate of 70 L / h, and the second fluid is air with a flow rate of 540 L / h. After detection, within the same time (3.8 min), the liquid volumes collected at the outlets of different channels are basically the same, with an average value of 561.125 g, and the non-uniformity of the local gas holdup distribution detected in each reaction channel is only 0.056, indicating that the fluid can be evenly distributed in the multi-channel microreactor. By the sampling average value, the number of channels, and the sampling time, the total flow rate of water can be obtained as 70.88 L / h, which is basically consistent with the 70 L / h detected before entering the reactor, indicating that the detected data used is accurate and reliable.

[0106] Example 3

[0107] The multi-channel microreactor shown in the appendix is adopted. Figure 1 The microreactor contains 4 reaction channels, each channel having a rectangular cross-section with a cross-sectional area of 10 mm 2 , the mixing channel is 120 mm long, and the length of the reaction channel is 8800 mm. Each mixing channel is provided with a distribution hole, and the inner diameter of the connecting pipe passing through the distribution hole is 1.5 mm. The length of the outlet section is 150 mm. The mixing section and the inlet section have no heat exchange function. 4-layer laminated tooth-shaped mixing components are adopted inside the reaction channel to enhance the fluid mixing inside the channel. The first fluid is diluted residue oil (the mass ratio of residue oil raw material to dilution solvent is 1:1), which contains an oil-soluble molybdenum-based catalyst (mass content 5%), and the flow rate at normal temperature is 16.56 L / h. The second fluid is hydrogen peroxide (concentration 30%), and the flow rate at normal temperature is 4.2 L / h. The two fluids that are mixed in the mixing channel enter the reaction channel for reaction. The reaction temperature is 85 °C, and the reaction pressure is normal pressure. The residue oil sample flowing out of the reactor is analyzed, and 55% of the thiophene substances contained in it are converted into sulfone substances. It shows that the provided multi-channel microreactor can complete the oxidation reaction of thiophene substances in a relatively short time.

[0108] Example 4

[0109] A multi-channel microreactor similar to that in Example 1 was used, except that the second fluid inlet was located in the inlet section. The first and second fluids entered the inlet section. The microreactor contained four reaction channels, each of which had a rectangular cross-section and a cross-sectional area of 10 mm. 2 The mixing channel is 20 mm long and the reaction channel is 100 mm long. Each mixing channel has a distribution hole, and the inner diameter of the connecting pipe passing through the distribution hole is 1 mm. The outlet section is 120 mm long. The mixing section and the inlet section have no heat exchange function. The first fluid is a 5-hydroxymethylfurfural aqueous solution with a concentration of 0.025 mol / L, which also contains NaOH with a molar ratio of 4:1 to 5-hydroxymethylfurfural. The flow rate at room temperature is 152.9 mL / h. The second fluid is O2, and the flow rate under standard conditions is 10.7 L / h. The first fluid and the second fluid flow into the microreactor in parallel at the bottom of the microreactor, and then pass through the mixing section. The O2 of the second fluid is dispersed into droplets and fully mixed with the solution of the first fluid, and then the gas-liquid mixture enters the reaction channel. The reaction channel is filled with Au / CeO2 powder catalyst. The reaction temperature is 90°C and the reaction pressure is 0.6 MPa. Under the action of the catalyst, 5-hydroxymethylfurfural can be oxidized to various oxidation products, the main product of which is 2,5-furandicarboxylic acid. Analysis of the liquid at the reactor outlet shows that the conversion rate of 5-hydroxymethylfurfural is 100%, and the selectivity of the main product 2,5-furandicarboxylic acid is 90%.

[0110] Comparative Example 1

[0111] Use the attached Figure 8 The multi-channel microreactor structure shown in FIG Figure 1 The main difference is that it does not contain a mixing section and the outlet section is 500 mm long. The microreactor system contains 108 reaction channels, each of which has a rectangular cross-section and a cross-sectional area of 54 mm. 2 The reaction channel is 1200 mm long. The first fluid and the second fluid flow in parallel into the reactor from the inlet section. The operating conditions are normal temperature and pressure. The first fluid is water, and the flow rate is 1m 3 / h, the second fluid is air, the flow rate is 4m 3 Observation showed that there were no bubbles in the 12 channels, and the fluid distribution was significantly uneven.

Claims

1. A multi-channel microreactor, characterized in that, It includes an inlet section (8), a mixing section (28), a reaction section (5), and an outlet section (3) that are connected in sequence; where: A first fluid inlet (2) is provided at the bottom of the inlet section. A mixing channel (30) is provided in the mixing section. The bottom of the mixing channel is open, and distribution holes (11) are provided on the tube wall of the mixing channel. A reaction channel (6) and a heat exchange channel are provided in the reaction section. The bottom of the reaction channel communicates with the mixing channel through a first orifice plate (18), and the heat exchange channel is provided with a heat exchange medium inlet (12) and a heat exchange medium outlet (13). The outlet section is provided with a top outlet (1), and the bottom communicates with the reaction channel through a second orifice plate (4). The outlet section is used to collect the materials in multiple reaction channels.

2. The multi-channel microreactor according to claim 1, characterized in that, The inlet section is an inverted conical cylinder, and the cone angle is 20 - 150°. Preferably, a conical dispersion member (9) is provided in the inlet section. The dispersion member is coaxial with the inlet section, and the distance between the bottom of the dispersion member and the bottom of the inlet section is 10 - 150 mm. Preferably, an inlet section heat exchange pipeline (23) is provided in the inlet section, and the heat exchange pipeline serves as a heat exchange medium channel.

3. The multi-channel microreactor according to claim 1, characterized in that, A uniform distribution plate (10) is provided at the bottom of the mixing section. The uniform distribution plate is made of porous material or has a sieve plate structure. Preferably, a baffle (17) is provided below the mixing channel, and the distance between the baffle and the bottom of the mixing channel is 5 - 50 mm.

4. The multi-channel microreactor according to claim 1, wherein The cross-sectional area of the mixing channel is 0.1 to 65 mm 2 , and the length is 10 to 500 mm; Preferably, the length of the mixing channel is 15 - 150 mm. Preferably, the mixing channel has a diameter-expanding structure from bottom to top.

5. The multi-channel microreactor according to claim 1, characterized in that, The aperture of the distribution holes on the mixing channel is 0.3 - 5 mm, and the center distance between two adjacent distribution holes is 5 - 100 mm, preferably 10 - 40 mm.

6. The multi-channel microreactor according to claim 1, wherein A guide cylinder (27) is provided in the mixing channel. The end face of the connecting pipe (26) extending into the guide cylinder (27) is an inclined plane, and its tip is located at the top of the inclined plane. The ratio of the cross-sectional area of the built-in guide cylinder (27) in the mixing channel (30) to the cross-sectional area of the mixing channel (30) is 0.1 - 0.6:

1. The distance between the top of the guide cylinder (27) and the top of the mixing channel (30) is 5 - 30 mm, and the distance between the bottom of the guide cylinder (27) and the bottom of the mixing channel (30) is 5 - 30 mm.

7. The multi-channel microreactor according to claim 1, characterized in that, A second fluid inlet (14) is provided on the side wall of the mixing section, and the distance between the second fluid inlet and the first orifice plate is 5 - 100 mm. Preferably, a heat exchange tube is provided in the mixing section.

8. The multi-channel microreactor according to claim 1, characterized in that, The mixing section has a shell-side heat exchange structure, and the inlet section is provided with a second fluid inlet (14).

9. The multi-channel microreactor according to claim 1, characterized in that, The distance between adjacent reaction channels is 1 to 50 mm, preferably 3 to 30 mm; the cross-sectional area of the reaction channels is 0.1 to 65 mm 2 , and the length is 50 to 20,000 mm; Preferably, the length of the reaction channel is 100 - 6000 mm. Preferably, internal components are provided in the reaction channel.

10. The multi-channel reactor according to claim 1 or 9, characterized in that, The volume ratio of the heat exchange channel in the reaction section to the reaction channel is 2 - 50:1, preferably 5 - 30:

1. Preferably, multiple baffle plates are provided in the heat exchange channel of the reaction section, and the distance between two adjacent baffle plates is 100 - 600 mm.

11. The multi-channel microreactor according to claim 1, characterized in that, The first orifice plate and / or the second orifice plate are internally provided with a heat exchange pipeline (21).

12. The multi-channel microreactor according to claim 1, characterized in that, The height of the outlet section is less than 15 cm. Preferably, a second outlet is further provided on the side wall at the bottom of the outlet section.

13. The multi-channel microreactor according to claim 1, wherein, The reaction section is divided into at least two sections, and each section communicates with each other through a second orifice plate.

14. A method for applying a multi-channel microreactor according to any one of claims 1 to 13, characterized in that, The liquid enters the inlet section from the first fluid inlet and flows upward into the mixing channel of the mixing section. The gas enters the mixing section from the second fluid inlet and enters the mixing channel through the distribution holes on the mixing channel. In the mixing channel, the liquid and the gas are mixed and flow upward through the first orifice plate into the reaction channel of the reaction section for reaction; the fluid that has completed the reaction leaves the reaction channel and enters the outlet section, and after converging in the outlet section, it is discharged from the reactor through the outlet; the volume ratio of the introduced gas to the liquid is 0.05 to 100:1, preferably 0.1 to 40:

1.

15. The application method of the multi-channel microreactor according to any one of claims 1-13, characterized in that, The first liquid enters the inlet section from the first fluid inlet and flows upward into the mixing channel of the mixing section. The second liquid enters the mixing section of the reactor from the second fluid inlet, and the second liquid enters the mixing channel through the distribution holes on the mixing channel to be mixed with the first liquid; the mixed fluid flows upward through the first orifice plate into the reaction channel of the reaction section for reaction; the fluid that has completed the reaction leaves the reaction channel and enters the outlet section, and after converging in the outlet section, it is discharged from the reactor through the outlet; wherein, the density of the first liquid is greater than that of the second liquid, and the volume ratio of the first liquid to the second liquid is 0.01 to 20:1, preferably 0.1 to 6:1.

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