A diffusion welding microchannel reactor with a supported catalyst

Abstract

The present invention belongs to the technical field of chemical reaction intensification, and specifically relates to a diffusion-welded microchannel reactor carrying a catalyst. The present invention provides a neck-shaped recess for fixing a solid catalyst on the reaction channel along the direction of fluid flow in the reaction channel of the reaction plate, which can solve the problem of accurately fixing the catalyst position in the channel of the diffusion-welded microchannel reactor and the weak heat exchange capacity of the reaction side under laminar flow. In addition, the catalyst replacement method of the present invention utilizes the combination of the catalyst and the detachable pipe box to solve the problem of the difficulty in replacing the solid catalyst in the microchannel. At the same time, the specific stacking form of the reaction plate and the heat exchange plate of the present invention can solve the problem of catalyst filling in the diffusion-welded microchannel reactor and the uneven temperature distribution of the reaction channel of the diffusion-welded microchannel reactor during the amplification process.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical reaction intensification, and in particular relates to a diffusion welding microchannel reactor carrying a catalyst. Background Art

[0002] Compared to batch reactors, microchannel reactors enable a more refined and continuous reaction process, precisely control reaction time, and improve reaction conversion and selectivity. They hold significant value in terms of experience, safety, and environmental protection in the field of chemical reaction intensification. However, due to the small size of microchannel reactors, they need to be scaled up to increase production.

[0003] To this end, the Chinese patent with the announcement number CN112403413B discloses an integrated countercurrent enhanced diffusion welding microchannel reactor. The diffusion welding microchannel reactor is characterized in that a plurality of parallel semicircular channels are first etched on each plate by chemical etching technology, and the channel radius is generally 0.5 to 2.5 mm. Then, a plurality of plates with parallel semicircular channels are welded to form a core body by a vacuum diffusion welding process, and finally a diffusion welding microchannel reactor with quantity amplification characteristics is formed through other processes. This diffusion welding microchannel reactor not only significantly improves the reactant flux, but also maintains the characteristics of high efficiency and compactness of the microchannel reactor. However, since most chemical reactions require solid catalysts, in addition to realizing the internal amplification process of the microchannel reactor, there are also high requirements for the technology of filling the microchannel with solid catalysts; simply performing internal amplification while ignoring the basic catalyst filling process is obviously inappropriate.

[0004] Currently, microchannels and solid catalysts can be combined in two ways: filling and coating. In a Chinese patent with publication number CN105968123B, the catalyst is made into a metal foam and filled into the channel. This utilizes the micropores of the metal foam to achieve the connection between the catalyst and the microchannel. The average pore size of the metal foam is 0.1 mm to 10 mm, and the length ranges from 10 mm to 1000 mm. The metal foam generally requires machining large grooves on a plate before it can be filled into the channel. This filling method is not suitable for diffusion-bonded microchannel reactors, and the metal foam filling presents significant flow resistance. In the Chinese patent application number CN115245790A, the catalyst is coated on the inner surface of the channel by dipping the channel into a liquid containing a precursor, then drying and calcining it. This method integrates the catalyst and the reactor. However, the obvious problem is that the amount of catalyst used in the channel is small, and it is difficult to replace the catalyst after it is deactivated. Most importantly, the vacuum diffusion welding process of the diffusion welding microchannel reactor requires a temperature of 1800°C to 2000°C. Even if the catalyst is first coated on the inner wall of the channel intact, it is difficult to ensure that the active components of the catalyst will not be deactivated in the ultra-high temperature environment during the diffusion welding process. Based on this, whether it is possible to develop a new type of diffusion welding microchannel reactor that can ensure its own high processing capacity and high compactness of the reaction materials while also having the advantages of easy filling of solid catalysts, simple positioning, and even convenient assembly and disassembly of the overall structure has become a technical problem that needs to be solved in recent years in this field. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a diffusion welding microchannel reactor with a catalyst, which can easily realize the precise fixation of the solid catalyst at a single point or even multiple points, which is conducive to improving the flexible use of the solid catalyst and effectively saving the reaction space of the reaction channel. The convenience of filling the solid catalyst can also be effectively guaranteed.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A diffusion-bonded microchannel reactor carrying a catalyst, characterized in that: along the direction of fluid flow in the reaction channel of a reaction plate, a constricted recess for fixing a solid catalyst is provided on the reaction channel; the recess satisfies the following relationship:

[0008]

[0009] in:

[0010] P n The position of the n-th level concave cavity with the material inlet of the reaction channel as the coordinate origin, in mm;

[0011] n is the number of levels of the concave holes;

[0012] L is the length of the reaction plate, in mm;

[0013] D n is the depression amplitude of the n-th level concave cavity, in mm;

[0014] i is the length of the necking section of the cavity, in mm.

[0015] Preferably, the solid catalyst is a cylindrical controllable structure catalyst with a hollow straight cylindrical shape, and a straight groove with a groove length direction parallel to the axis of the solid catalyst is provided on the outer wall of the solid catalyst, and the bottom of the straight groove and the hollow channel of the solid catalyst are connected to each other by a radially extending connecting hole; the minimum depth of the straight groove is greater than or equal to 0.5 mm; the straight groove constitutes a turbulent flow area, and the solid area of the solid catalyst constitutes a porous medium area; the hydraulic radius of the solid catalyst is 0.5 to 2.5 mm, and the hydraulic radius is smaller than the hydraulic radius of the reaction channel and greater than the hydraulic radius of the recess with the largest depression amplitude, the length of the solid catalyst is 1 to 10 mm, and the difference between the diameter of the solid catalyst and the diameter of the reaction channel is less than 0.1 mm.

[0016] Preferably, the solid catalyst is a cylindrical controllable structure catalyst with a hollow straight cylindrical shape, and the outer wall and inner wall of the solid catalyst are provided with W-shaped grooves that pass through both ends of the solid catalyst, and the bottom of the W-shaped groove and the hollow channel of the solid catalyst are connected to each other by radially extending connecting holes; the minimum depth of the W-shaped groove is greater than or equal to 0.5 mm; the W-shaped groove constitutes a turbulent flow area, and the solid area of the solid catalyst constitutes a porous medium area; the hydraulic radius of the solid catalyst is 0.5 to 2.5 mm, and the hydraulic radius is smaller than the hydraulic radius of the reaction channel and greater than the hydraulic radius with the largest depression amplitude, the length of the solid catalyst is 1 to 10 mm, and the difference between the diameter of the solid catalyst and the diameter of the reaction channel is less than 0.1 mm.

[0017] Preferably, the solid catalyst is a spherical controlled structure catalyst with a hollow spherical appearance, and a through hole is radially provided between the outer wall and the inner wall of the solid catalyst, and the minimum pore diameter of the through hole is greater than or equal to 0.5 mm; the through hole constitutes a turbulent flow area, and the solid area of the solid catalyst constitutes a porous medium area; the hydraulic radius of the solid catalyst is 0.5 to 2.5 mm, and the hydraulic radius is smaller than the hydraulic radius of the reaction channel and larger than the hydraulic radius of the recess with the largest depression amplitude, and the difference between the diameter of the solid catalyst and the diameter of the reaction channel is less than 0.1 mm.

[0018] Preferably, the porous medium region is formed by a calcination process, the pore diameter in the porous medium region is 1 to 100 μm, and the porosity is 20% to 45%;

[0019] Preferably, the catalyst replacement method comprises the following steps:

[0020] S1. Disassemble the reaction inlet pipe box;

[0021] S2. The reaction outlet pipe box is fed with a high-pressure drying fluid, so that the high-pressure drying fluid enters the reaction channel through the material outlet of the reaction plate, and the original solid catalyst in the reaction channel is flushed out;

[0022] S3. Filling the reaction channel with new solid catalyst;

[0023] S4. Reinstall the reaction inlet pipe box to complete the catalyst replacement process.

[0024] Preferably, it also includes a core body, including a first heat exchange plate, a first reaction plate, a second reaction plate and a second heat exchange plate stacked in sequence from top to bottom, the adjacent surfaces of the first reaction plate and the second reaction plate are both concavely provided with grooves, so that when the two reaction plates are fitted together, the grooves on the two reaction plates cooperate with each other to form the reaction channel, the first heat exchange plate has an upper heat exchange channel or the prefabricated grooves at the first heat exchange plate cooperate with the upper surface of the first reaction plate to form the upper heat exchange channel, the second heat exchange plate has a lower heat exchange channel or the prefabricated grooves at the second heat exchange plate cooperate with the lower surface of the second reaction plate to form the lower heat exchange channel; a projection plane is made along the assembly direction parallel to the core body, and the directions of the pipe openings between the upper heat exchange channel and the reaction channel and between the lower heat exchange channel and the reaction channel are all intersected with each other, and the reaction channel and the remaining channel areas of the two heat exchange channels overlap with each other.

[0025] Preferably, the first heat exchange plate, the first reaction plate, the second reaction plate and the second heat exchange plate stacked in sequence from top to bottom form a submodule, and the submodules are more than two groups and are assembled in sequence along the assembly direction of the core.

[0026] Preferably, the upper heat exchange flow channel and the lower heat exchange flow channel of the core body overlap with each other in the projection parallel to the assembly direction of the core body; the pipe inlet and pipe outlet of each heat exchange flow channel of the core body are respectively arranged with a heat exchange inlet pipe box and a heat exchange outlet pipe box, and the pipe inlet end and pipe outlet end of the reaction flow channel of the core body are respectively fixed to the reaction outlet pipe box and the reaction inlet pipe box, wherein:

[0027] The core body and the reaction inlet pipe box are connected by bolts and sealing gaskets to form a detachable threaded seal, and the other end of the core body is welded to the reaction outlet pipe box; the heat exchange inlet pipe box and the heat exchange outlet pipe box are respectively welded to both sides of the core body.

[0028] Preferably, the fluid flow direction in the reaction channel and each heat exchange channel is downstream or countercurrent or crossflow or cross-counterflow; the cross-section of the groove and the prefabricated groove at the two heat exchange plates is a semicircular groove or a semi-elliptical groove or a rectangular groove or an arched groove with a hydraulic radius of 0.5 to 2 mm, and the flow channel form of the groove and the prefabricated groove at the two heat exchange plates is a straight channel or a wavy flow channel or a zigzag flow channel; the material of each reaction plate and each heat exchange plate is stainless steel or titanium or nickel-based alloy or Hastelloy alloy, and the processing method of each reaction plate and each heat exchange plate is chemical etching or machining.

[0029] The beneficial effects of the present invention are:

[0030] 1) Through the above scheme, the present invention relies on arranging recesses in the reaction channel of the microchannel reactor, which can easily realize the precise fixation of a single point or even multiple points of the solid catalyst, improve the flexible use of the solid catalyst, and effectively save the reaction space of the reaction channel. During actual use, due to the presence of recesses, after the solid catalyst is filled from the entrance, it can slide to the recess by gravity or under the push of the fluid, and has the characteristics of convenient filling and accurate positioning. In addition, multi-stage recesses are also conducive to enhancing the heat exchange capacity of the reaction side, especially in order to achieve a sufficiently long residence time and make the reaction side flow state laminar, the presence of multi-stage recesses can cause flow velocity changes many times, accurately control the location where turbulence occurs, and destroy the fluid boundary layer at multiple points, thereby improving the problem that the heat exchange capacity of the core reaction area is difficult to improve under the laminar state.

[0031] 2) Furthermore, the present invention also controls the structure of the solid catalyst in a controllable manner, solves the problem of matching commercial catalysts with traditional microchannel reactors, and customizes the structure of the solid catalyst to adapt it to the external structure of different channel types. For example: for a zigzag microchannel, the external structure of the solid catalyst can be made into a spherical shape to facilitate the filling of the solid catalyst; for a straight channel microchannel, the solid catalyst can also be made into a cylindrical shape, so that it can be filled into the microchannel while enhancing the heat and mass transfer capacity of the solid catalyst. Compared with traditional commercial catalysts, the structure of the solid catalyst of the present invention, that is, the controllable structure catalyst, is controllable and has higher manufacturing precision. By controlling the structure of the solid catalyst, the solid catalyst entity part is made into a porous medium, so that the material can still contact the active components in the entity part by diffusion. In addition, holes or grooves are formed on the surface of the entity part, which reduces the space occupied by the solid catalyst in the microchannel, reduces the pressure drop in the microchannel, saves pump work, and facilitates the filling of the solid catalyst into or blowing out of the microchannel. Furthermore, the presence of grooves or holes on the outer and even inner walls of the solid catalyst can also help form special channels between the solid catalyst and the flow channel, promoting heat and mass transfer, enhancing heat conduction and convection, reducing thermal resistance, increasing convection heat transfer coefficient, and reducing heat loss. The presence of special channels can also control the direction of material flow, enabling customization of the catalyst reaction process path, and improving reaction selectivity and conversion rate.

[0032] 3) Spherical solid catalysts are more suitable for wavy reaction channels, solving the problem of catalyst filling difficulties in tortuous channels. By utilizing the low resistance of spherical motion, spherical solid catalysts can flow flexibly within microchannels or reaction channels. Furthermore, the use of spherical solid catalysts ensures that any spherical surface intersecting the flow direction has the same structure, ensuring that the chemical reaction effect will not vary significantly when the fluid passes through any spherical surface of the axisymmetric spherical solid catalyst in any direction.

[0033] 4) In actual design, relying on the above-mentioned specific solid catalyst, the adaptation problem of the solid catalyst and the microchannel shape can be further solved; by high-precision customization of the solid catalyst structure and size, the heat and mass transfer process of the solid catalyst can be further enhanced, and efficient coordination with the multi-level recesses can be achieved, ultimately making it easier to fill, fix, and replace the catalyst.

[0034] 5) As a preferred alternative to the above scheme, the present invention also ensures a 1:1 heat exchange process within each reaction channel by overlapping the corresponding reaction plates and heat exchange plates, improving temperature uniformity and temperature control capabilities within the reaction channels, thereby enhancing conversion and selectivity within the reaction channels. Furthermore, by configuring the two reaction plates as mirror images, they interlock while maintaining microchannel characteristics, increasing the usable space within the reaction channel, increasing material throughput, and reducing channel pressure drop. This significantly further optimizes catalyst filling, fixation, and replacement.

[0035] 6) By arranging multiple parallel flow channels on the heat exchange plates and reaction plates and stacking multiple plates to form a core, the reaction material processing capacity of the diffusion-bonded microchannel reactor was increased. Furthermore, the heat exchange and reaction channels intersect at the inlet and outlet, while remaining overlapping along the stacking direction. This not only facilitates the rational layout of the corresponding tube boxes, but also ensures temperature control of the reaction channels by the heat exchange channels, and uniforms the thermal efficiency of multiple reaction channels.

[0036] 7) bolt fastening and sealing gasket such as multiple chemical corrosion resistant washers are used to cooperate as the sealing method of the reaction inlet pipe box, which solves the contradiction that the traditional full diffusion microchannel reactor needs to face before filling the catalyst and then performing vacuum diffusion welding sealing, and avoids the overheating deactivation of the solid catalyst under ultra-high temperature diffusion welding environment. At the same time, the present invention can realize the filling of the solid catalyst before the detachable diffusion welding microchannel reactor is sealed by the detachable reaction inlet pipe box, and can also be directly replaced online by disassembling the reaction inlet pipe box and relying on the purge mode to complete the solid catalyst after the solid catalyst is deactivated, which is very flexible and convenient to use. The use of multiple chemical corrosion resistant washers can prevent the reaction materials from corroding the washers and causing material leakage, and can also solve the multiple elastic compensation problems that may exist in the mechanical sealing method under the conditions of large temperature change caused by the reaction, and prevent the material leakage caused by the loss of bolts and pre-tightening under the temperature change condition.

[0037] 8) From the above, it can be seen that the microchannel reactor of the present invention has the advantages of convenient catalyst fixation and simple catalyst replacement process. In addition, the reactor simultaneously utilizes microchannels to enhance the reaction and heat exchange process, has a small device footprint, and is easy to install. The present invention also provides a catalyst structure with a controllable structure to solve the problems of rapid catalyst filling and online replacement. The controllable catalyst structure can even further achieve customization of the catalytic reaction path, with significant results. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a diagram showing the arrangement of the recesses;

[0039] Figure 2 This is a disassembled state diagram of the solid catalyst and reaction plate;

[0040] Figure 3 、 Figure 4 and Figure 5 Schematic diagrams of the three-dimensional structures of three embodiments of solid catalysts;

[0041] Figure 6 Schematic diagram of the three-dimensional structure of the heat exchange plate;

[0042] Figure 7 Schematic diagram of the core body in disassembled state;

[0043] Figure 8 Schematic diagram of the three-dimensional structure of the microchannel reactor.

[0044] The actual correspondence between the reference numerals and component names of the present invention is as follows:

[0045] 10-core; 10a-first reaction plate; 10b-second reaction plate; 10c-first heat exchange plate; 10d-second heat exchange plate; 11-recess; 12-groove; 13-prefabricated groove;

[0046] 20-solid catalyst; 21-porous medium region; 22-turbulent flow region;

[0047] 31-reaction inlet pipe box; 32-reaction outlet pipe box;

[0048] 41-heat exchange inlet pipe box; 42-heat exchange outlet pipe box;

[0049] 50-bolts. DETAILED DESCRIPTION

[0050] For ease of understanding, here we combine Figure 1-8 The specific structure and working mode of the present invention are further described as follows:

[0051] The specific implementation structure of the present invention is shown in FIG. Figure 8 As shown, the core 10 formed by each reaction plate and heat exchange plate is matched with the corresponding pipe box and finally assembled to form Figure 8 The microchannel reactor shown.

[0052] More specifically, Figure 8 The structure shown first includes a reaction-heat exchange functional unit, namely the core 10, and also includes four pipe boxes in different directions, namely the reaction inlet pipe box 31, the reaction outlet pipe box 32, the heat exchange inlet pipe box 41 and the heat exchange outlet pipe box 42. The reaction-heat exchange functional unit includes multiple groups of submodules, each group of submodules is as shown. Figure 7The first heat exchange plate 10c, the first reaction plate 10a, the second reaction plate 10b, and the second heat exchange plate 10d are stacked in order from top to bottom. In this case, the first reaction plate 10a and the second reaction plate 10b constitute the aforementioned reaction plate, and the first heat exchange plate 10c and the second heat exchange plate 10d constitute the aforementioned heat exchange plate.

[0053] In addition, if Figure 2 As shown, after the reaction channel formed by the grooves 12 of the first reaction plate 10a and the second reaction plate 10b is used to accommodate the solid catalyst 20, the fluid flow direction of the reaction channel and the fluid flow direction of the heat exchange channel formed by the prefabricated grooves 13 on the two heat exchange plates have both overlapping and intersecting characteristics in the projection in the stacking direction. In other words, the projection of part of the flow channel at the inlet and outlet of the heat exchange plate in the stacking direction intersects with the reaction channel, while the remaining part of the flow channel coincides with the projection of the reaction channel in the stacking direction. Figure 7 At this time, when projecting along the assembly direction of the parallel core 10, the nozzles between the upper heat exchange channel and the reaction channel, as well as between the lower heat exchange channel and the reaction channel, intersect with each other, and the reaction channel and the remaining channel areas of the two heat exchange channels overlap with each other.

[0054] Furthermore, the grooves 12 at each reaction plate can be implemented in various ways, such as straight grooves or wavy grooves, etc., which can correspondingly form straight flow channel type reaction-heat exchange functional subunits and wavy flow channel type reaction-heat exchange functional subunits.

[0055] In order to precisely control the fixed position of the solid catalyst 20, the present invention can further provide multi-level recesses 11 in the flow channel of the reaction plate to flexibly fix the catalyst position. The arrangement position of the recesses 11 satisfies the following relationship: Where n is the number of stages, L is the length of the plate; the amplitude of the recess 11 satisfies the relationship: D (n) = 0.1n; all units above are millimeters. At this point, with the material inlet of the reaction channel as the coordinate origin, the first-stage recess 11 is located at the center of the plate, with a width of 0.1mm. The second-stage recess 11 is located at 0.75L of the plate, with a width of 0.2mm, and so on. The length of the recess 11 is 1-3mm.

[0056] Furthermore, each heat exchange plate can be further divided into straight-flow heat exchange plates and wavy-flow heat exchange plates based on different flow channel forms. The working medium flowing in the heat exchange plate is the second-flow working medium, and the working medium flowing in the reaction plate is the first-flow working medium. The flow directions of the first-flow working medium and the second-flow working medium can be co-current or counter-current with each other. The appropriate flow direction can be freely selected based on the physical and chemical properties of the first-flow working medium and the second-flow working medium as well as the desired chemical reaction temperature gradient distribution control.

[0057] Specifically, the reaction inlet pipe box 31 in this embodiment is a detachable mechanically sealed pipe box, and the opposite side is the reaction outlet pipe box 32; if the detachable diffusion-welded microchannel reactor requires the flow direction relationship between the first and second flow working fluids to be in a co-current flow form during use, then the heat exchange inlet pipe box 41 for the second flow working fluid and the heat exchange outlet pipe box 42 for the second flow working fluid are connected to the pipe openings of the heat exchange plate. If the detachable diffusion-welded microchannel reactor requires the flow direction relationship between the first and second flow working fluids to be in a counter-current flow form during use, the reaction inlet pipe box 31 and the reaction outlet pipe box 32 remain unchanged, and the heat exchange inlet pipe box 41 and the heat exchange outlet pipe box 42 can be swapped. In addition, in order to facilitate the filling and replacement of the solid catalyst 20, the present invention sets the reaction inlet pipe box 31 as a mechanically sealed pipe box; the other pipe boxes are diffusion-welded sealed pipe boxes, which cannot be disassembled without damaging the core 10. In order to achieve good sealing performance, corresponding matching grooves and sealing gaskets are respectively provided at the mechanical matching points between the core body 10 and the corresponding pipe box; the matching grooves and sealing gaskets can be multi-layered, mainly to prevent chemical corrosion and temperature changes that may cause the bolts 50 to lose pre-tightening, and to prevent the leakage of chemical materials and reaction products.

[0058] Specifically, Figure 2-5 A cylindrical solid catalyst 20 and a spherical solid catalyst 20 are also provided.

[0059] When the solid catalyst 20 is a cylindrical controllable structure catalyst with a hollow right cylindrical shape, a straight groove with a groove length direction parallel to the axis of the solid catalyst 20 is provided on the outer wall of the solid catalyst 20, and the bottom of the straight groove and the hollow channel of the solid catalyst 20 are connected to each other by radially extending connecting holes; the minimum depth of the straight groove is greater than or equal to 0.5 mm; the straight groove constitutes a turbulent flow area 22, and the solid area of the solid catalyst 20 constitutes a porous medium area 21.

[0060] When the solid catalyst 20 is a cylindrical controllable structure catalyst with a hollow straight cylindrical shape, the outer wall and inner wall of the solid catalyst 20 are both provided with W-shaped grooves that pass through both ends of the solid catalyst 20, and the bottom of the W-shaped groove and the hollow channel of the solid catalyst 20 are connected to each other by radially extending connecting holes; the minimum depth of the W-shaped groove is greater than or equal to 0.5 mm; the W-shaped groove constitutes a turbulent flow area 22, and the solid area of the solid catalyst 20 constitutes a porous medium area 21.

[0061] When the solid catalyst 20 is a spherical controllable structure catalyst with a hollow spherical appearance, a through hole is radially provided between the outer wall and the inner wall of the solid catalyst 20, and the minimum pore diameter of the through hole is greater than or equal to 0.5 mm; the through hole constitutes a turbulent flow area 22, and the solid area of the solid catalyst 20 constitutes a porous medium area 21.

[0062] At the same time, the hydraulic radius of the solid catalyst 20 is 0.5-2.5 mm, which is smaller than the hydraulic radius of the reaction channel and larger than the hydraulic radius of the cavity 11 with the largest depression amplitude. The difference between the diameter of the solid catalyst 20 and the diameter of the reaction channel is less than 0.1 mm.

[0063] It can be seen that the above three types of solid catalysts 20, namely Figure 3-5 The porous medium region 21 of the controllable structure catalyst shown contains a large number of pores with characteristic dimensions in the micrometer range, which are mainly generated during the catalyst carrier molding process; when the first flow medium passes through the porous medium region 21, its flow path is uncontrollable, and the flow form is mainly concentration diffusion; the turbulent flow region 22 of the controllable structure catalyst is set as a combination of holes and / or grooves, and can even be grooves with a tortuous path or axisymmetric equal-diameter holes. The structure and form of the turbulent flow zone can be determined according to the physical properties, chemical properties and required heat transfer-mass transfer effect of the fluid medium. The purpose of the turbulent flow region 22 is to reduce the proportion of the first flow medium flowing through the catalyst in an infiltration manner, increase the turbulence level of the first flow medium, reduce the thermal conductivity of the catalyst, increase the convective heat transfer coefficient of the first flow medium, and ultimately improve the selectivity and conversion rate of the catalytic reaction by customizing the catalytic reaction path.

[0064] Example 1:

[0065] To facilitate further understanding of the present invention, the chemical reaction of methanol reforming to produce hydrogen is taken as an example. The main steps are as follows:

[0066] Sa. Prepare the slurry required for the Cu / ZnO / Al2O3 catalyst, then use digital light-curing 3D printing technology to print the slurry into a green body with a controllable structure. The green body is calcined to form a catalyst carrier. Finally, the active component is added to the carrier, dried, and calcined to form a catalyst with a controllable structure.

[0067] Sb. A reaction channel and a heat exchange channel with multi-stage recesses 11 are formed by chemical etching, and the corresponding reaction plates and heat exchange plates are stacked according to a specific stacking rule, and then the core 10 is formed by vacuum diffusion welding. The specific stacking rule takes two reaction plates and two heat exchange plates as a sub-stack unit or sub-module as an example: the two reaction plates are tightly fastened to each other and form a stacking form of the first heat exchange plate 10c-first reaction plate 10a-second reaction plate 10b-second heat exchange plate 10d with the other two heat exchange plates. After the core 10 is formed, an upper clamping plate and a lower clamping plate can be additionally arranged; of course, it can also be as follows Figure 8As shown, the top and bottom heat exchange plates of the core 10 are directly fixed to their corresponding manifolds. Subsequently, the heat exchange inlet manifold 41, heat exchange outlet manifold 42, and reaction outlet manifold 32 are welded and sealed to the core 10. After the solid catalyst 20 is filled in the next step, the reaction inlet manifold 31 and the core 10 are finally sealed. This sealing method can be mechanical or welded. To facilitate catalyst replacement, Example 1 uses a mechanical seal, which is easier to disassemble.

[0068] Sc. After filling and sealing the solid catalyst 20, the diffusion-bonded microchannel reactor carrying the solid catalyst 20 is connected to the methanol reforming hydrogen production system. A preheated methanol-water vapor mixture is continuously introduced into the reaction side, followed by clean, high-temperature thermal oil into the heat exchange side. After the reaction begins, hydrogen is collected at the reaction outlet manifold 32, and the heat-exchanged thermal oil is collected at the heat exchange outlet manifold 42.

[0069] Sd. When the solid catalyst 20 in the diffusion-welded microchannel needs to be replaced: first disassemble the diffusion-welded microchannel reactor, then remove the reaction inlet pipe box 31. Next, introduce high-pressure dry fluid, such as high-pressure nitrogen or air, into the reaction outlet pipe box 32. After all used solid catalysts 20 are blown out, refill with new solid catalysts 20, then reinstall the reaction inlet pipe box 31. Finally, place the microchannel reactor after replacing the solid catalyst 20 on the methanol reforming hydrogen production platform to prepare for the next use.

[0070] The overall catalyst macrostructure provided by the above step Sa can be referred to Figure 3 As shown, the solid catalyst 20 has a length of 10 mm and an outer diameter of 3.8 mm. The outer edge of the solid catalyst is provided with eight grooves with a rectangular cross-section, a length of 1 mm, and a width of 0.5 mm. The grooves are provided with five equally spaced connecting holes with a pore diameter of 0.5 mm.

[0071] The reaction channel of the reaction plate provided in the above step Sb is a straight channel with three levels of recesses 11, the length of each recess 11 is 2 mm, the position of the first-level recess 11 is located at the 1 / 2 position of the plate, and the diameter of the recess 11 is 3.9 mm; the second-level recess 11 is located at the 3 / 4 position of the plate, and the diameter of the recess 11 is 3.8 mm; the third-level recess 11 is located at the 7 / 8 position of the plate, and the diameter of the recess 11 is 3.7 mm. Therefore, according to the external dimensions of the controllable structure catalyst, the catalyst fixing position will start from the position of the second-level recess 11.

[0072] The methanol vapor in step Sc above originates from the evaporator. A methanol-water solution is first passed through the evaporator. After the methanol vapor is preheated to above 100°C via electrical heating, it is passed into the reaction side of the microchannel reactor. The preheating temperature of the methanol vapor can be adjusted according to reaction requirements. A regulating valve is provided between the evaporator and the core 10 to adjust the inlet flow rate of the methanol vapor. Furthermore, the temperature of the thermal oil entering the heat exchange side of the core 10 is controlled between 260°C and 300°C to improve methanol conversion. The methanol reforming reaction will continue automatically until completion.

[0073] The pressure of the high-pressure nitrogen or air used in the above step Sd is about 4 MPa; before removing the reaction inlet pipe box 31 and reinstalling it, it should be considered to replace the sealing gasket between the reaction inlet pipe box 31 and the core body 10 with a new one.

[0074] It can be seen from this that the microchannel reactor or microchannel reactor of the present invention is suitable for chemical reactions that are temperature-sensitive and require a solid catalyst 20, such as alcohol reforming reactions, alkane reforming reactions, etc. It is also suitable for chemical reactions that are temperature-sensitive but do not require a solid catalyst 20, such as nitration reactions, etc. It is also suitable for hydrogenation reactions that need to be carried out under a high-pressure environment.

[0075] Of course, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also encompasses the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that fall within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0076] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0077] The technology, shape, and structure not described in detail in the present invention are all well-known technologies.

Claims

1. A diffusion-bonded microchannel reactor with a catalyst, characterized in that: Along the direction of fluid flow in the reaction channel of the reaction plate, a concave cavity (11) with a constricted shape for fixing the solid catalyst (20) is provided on the reaction channel; the concave cavity (11) satisfies the following relationship: ； in: P n When the material inlet of the reaction channel is taken as the coordinate origin, n The position point of the concave hole (11) of the first level, in mm; n is the number of levels of the concave holes (11), n >1; L is the length of the reaction plate, in mm; D n For the n The depression amplitude of the first-level concave cavity (11), in mm; i is the length of the necking section of the cavity (11), in mm.

2. The catalyst-supported diffusion bonding microchannel reactor according to claim 1, characterized in that: The solid catalyst (20) is a cylindrical controllable structure catalyst having a hollow straight cylindrical shape. A straight groove is provided on the outer wall of the solid catalyst (20) with the groove length direction parallel to the axis of the solid catalyst (20). The bottom of the straight groove and the hollow channel of the solid catalyst (20) are connected to each other by a radially extending connecting hole. The minimum depth of the straight groove is greater than or equal to 0.5 mm. The straight groove constitutes a turbulent flow area (22), and the solid area of the solid catalyst (20) constitutes a porous medium area (21). The hydraulic radius of the solid catalyst (20) is 0.5-2.5 mm, and the hydraulic radius is smaller than the hydraulic radius of the reaction channel and larger than the hydraulic radius of the recess (11) with the largest depression amplitude. The length of the solid catalyst (20) is 1-10 mm, and the difference between the diameter of the solid catalyst (20) and the diameter of the reaction channel is less than 0.1 mm.

3. The catalyst-supported diffusion bonding microchannel reactor according to claim 1, characterized in that: The solid catalyst (20) is a cylindrical controllable structure catalyst having a hollow straight cylindrical shape. The outer wall and inner wall of the solid catalyst (20) are both provided with W-shaped grooves penetrating the two ends of the solid catalyst (20). The bottom of the W-shaped groove and the hollow channel of the solid catalyst are connected to each other by radially extending connecting holes. The minimum depth of the W-shaped groove is greater than or equal to 0.5 mm. The W-shaped groove constitutes a turbulent flow area (22), and the solid area of the solid catalyst (20) constitutes a porous medium area (21). The hydraulic radius of the solid catalyst (20) is 0.5-2.5 mm, and the hydraulic radius is smaller than the hydraulic radius of the reaction channel and larger than the hydraulic radius of the maximum depression amplitude. The length of the solid catalyst (20) is 1-10 mm, and the difference between the diameter of the solid catalyst (20) and the diameter of the reaction channel is less than 0.1 mm.

4. The catalyst-supported diffusion bonding microchannel reactor according to claim 1, characterized in that: The solid catalyst (20) is a spherical controllable structure catalyst having a hollow spherical shape. A through hole is radially provided between the outer wall and the inner wall of the solid catalyst (20), and the minimum pore size of the through hole is greater than or equal to 0.5 mm. The through hole constitutes a turbulent flow area (22), and the solid area of the solid catalyst (20) constitutes a porous medium area (21). The hydraulic radius of the solid catalyst (20) is 0.5-2.5 mm, and the hydraulic radius is smaller than the hydraulic radius of the reaction channel and larger than the hydraulic radius of the recess (11) with the largest depression amplitude. The difference between the diameter of the solid catalyst (20) and the diameter of the reaction channel is less than 0.1 mm.

5. A diffusion-bonded microchannel reactor with catalyst according to claim 2, 3 or 4, characterized in that: The porous medium region (21) is formed by a calcination process, and the pore diameter in the porous medium region (21) is 1-100 μm, and the porosity is 20%-45%.

6. A diffusion-bonded microchannel reactor with a catalyst according to claim 2, 3 or 4, characterized in that: The catalyst replacement method includes the following steps: S1. Disassemble the reaction inlet pipe box (31); S2. A high-pressure drying fluid is introduced into the reaction outlet pipe box (32), so that the high-pressure drying fluid enters the reaction channel through the material outlet of the reaction plate, and the original solid catalyst (20) in the reaction channel is flushed out; S3. Filling new solid catalyst (20) into the reaction channel from the inlet of the reaction plate; S4. Reinstall the reaction inlet pipe box (31) to complete the catalyst replacement process.

7. A diffusion-bonded microchannel reactor with a catalyst according to claim 1, 2, 3 or 4, characterized in that: The core body also includes a first heat exchange plate (10c), a first reaction plate (10a), a second reaction plate (10b) and a second heat exchange plate (10d) stacked in order from top to bottom, the adjacent surfaces of the first reaction plate (10a) and the second reaction plate (10b) are both concavely provided with grooves (12), so that when the two reaction plates are attached to each other, the grooves (12) on the two reaction plates cooperate with each other to form the reaction channel, the first heat exchange plate (10c) carries the upper heat exchange channel or the first heat exchange plate ( The prefabricated groove at 10c) cooperates with the upper plate surface of the first reaction plate (10a) to form an upper heat exchange flow channel, and the second heat exchange plate (10d) has a lower heat exchange flow channel or the prefabricated groove at the second heat exchange plate (10d) cooperates with the lower plate surface of the second reaction plate (10b) to form a lower heat exchange flow channel; a projection plane is made along the assembly direction of the parallel core (10), and the directions of the pipe openings between the upper heat exchange flow channel and the reaction flow channel and between the lower heat exchange flow channel and the reaction flow channel are all intersected with each other, and the reaction flow channel and the remaining flow channel areas of the two heat exchange flow channels overlap with each other.

8. The catalyst-supported diffusion bonding microchannel reactor according to claim 7, characterized in that: A first heat exchange plate (10c), a first reaction plate (10a), a second reaction plate (10b), and a second heat exchange plate (10d) stacked in sequence from top to bottom form a submodule. The submodules consist of two or more groups and are assembled in sequence along the assembly direction of the core (10).

9. The catalyst-supported diffusion-bonded microchannel reactor according to claim 7, characterized in that: The upper heat exchange flow channel and the lower heat exchange flow channel at the core (10) overlap with each other in a projection parallel to the assembly direction of the core (10); the pipe inlet and pipe outlet of each heat exchange flow channel of the core (10) are respectively arranged with a heat exchange inlet pipe box (41) and a heat exchange outlet pipe box (42), and the pipe outlet end and pipe inlet end of the reaction flow channel of the core (10) are respectively fixed to the reaction outlet pipe box (32) and the reaction inlet pipe box (31), wherein: The core (10) and the reaction inlet pipe box (31) are connected by bolts (50) and sealing gaskets to form a detachable threaded seal, and the other end of the core (10) is welded to the reaction outlet pipe box (32); the heat exchange inlet pipe box (41) and the heat exchange outlet pipe box (42) are respectively welded to both sides of the core (10).

10. The catalyst-supported diffusion bonding microchannel reactor according to claim 9, characterized in that: The flow direction of the fluid in the reaction channel and each heat exchange channel is downstream or countercurrent or cross-flow or cross-countercurrent; the cross section of the groove (12) and the prefabricated groove (13) at the two heat exchange plates is a semicircular groove or a semi-elliptical groove or a rectangular groove or an arched groove with a hydraulic radius of 0.5 to 2 mm, and the flow channel form of the groove (12) and the prefabricated groove (13) at the two heat exchange plates is a straight channel or a wavy flow channel or a zigzag flow channel; the material of each reaction plate and each heat exchange plate is stainless steel or titanium or nickel-based alloy or Hastelloy alloy, and the processing method of each reaction plate and each heat exchange plate is chemical etching or machining.

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