A SiC reactor for cyclohexanone ammoximation and a design method thereof

Abstract

The application discloses a SiC reactor for cyclohexanone aminooxidation and a design method thereof, and relates to the technical field of chemical reactors. The SiC reactor comprises a reactor shell, a plurality of reaction channels, a plurality of composite plates, and a plurality of reaction channels. The axis direction of the reaction channel is parallel to the axis direction of the reactor shell. The plurality of composite plates are arranged in the plurality of reaction channels. The flat plate and the corrugated plate made of silicon carbide are arranged in the axial direction of the reaction channel and matched with the rhombic through-hole structure. The fluid in the reaction channel can be disturbed, the radial diffusion effect of the fluid is improved, and the effective residence time of the fluid is prolonged. Based on the excellent heat conduction performance of silicon carbide and the plate combination structure, the heat exchange between the wall surface and the fluid is strengthened, the temperature field distribution in the channel is optimized, the mass transfer and heat transfer conditions of the material are improved, and the generation effect of cyclohexanone oxime is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical reactor technology, and in particular to a SiC reactor for the ammonium oximeation of cyclohexanone and its design method. Background Technology

[0002] Cyclohexanone ammoniation is the core process for producing caprolactam, characterized by strong exothermicity, multiphase transformation, and limited mass transfer. With the continuous upgrading of the chemical industry, higher demands are placed on the process control of cyclohexanone ammoniation. As a key piece of equipment in the cyclohexanone ammoniation reaction, the reactor is gradually becoming the preferred equipment for this process.

[0003] With the development of the industry, silicon carbide (SiC) based monolithic reactors have become a research hotspot due to their high thermal conductivity, high specific surface area and low pressure drop characteristics. They usually adopt a simple straight channel design and carry out catalytic reactions and media flow through a regular arrangement of through holes.

[0004] However, in existing silicon carbide-based monolithic reactors, radial mixing of materials within the straight channels mainly occurs through molecular diffusion. Under low flow rates, this diffusion is prone to incomplete mixing, leading to uneven reactant concentrations between the channel center and the walls. Furthermore, heat is difficult to dissipate rapidly from the channel center, and increasing the channel's tortuosity results in a significant increase in pressure drop. Therefore, existing technologies suffer from insufficient molecular diffusion and poor heat transfer efficiency within straight channels. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a SiC reactor and its design method for the aminooximation of cyclohexanone, which solves the technical problems of insufficient molecular diffusion and poor heat transfer efficiency in straight channels in existing technologies.

[0006] The technical means employed in this invention are as follows:

[0007] In a first aspect, embodiments of the present invention provide a SiC reactor for the ammonium oximeation of cyclohexanone, comprising: Reactor shell; Multiple reaction channels are arranged in an array within the reactor shell, and the axial direction of the reaction channels is parallel to the axial direction of the reactor shell. Multiple composite plates are disposed within multiple reaction channels. Each composite plate includes multiple first plates and multiple second plates. The first plates and the second plates are spaced apart along the axial direction of the reaction channel. The first plates have multiple first through holes, and the second plates have multiple second through holes. The first plate is a flat plate, the second plate is a corrugated plate, the first through hole and the second through hole are both rhomboid in shape, the corresponding sides of the first plate and the second plate have a preset angle, and the reactor shell, the reaction channel and the composite plate are all made of silicon carbide.

[0008] Furthermore, a plurality of first through holes are arranged in an array on the first plate, and a plurality of second through holes are arranged in an array on the second plate.

[0009] Furthermore, the angle between the corresponding edges of the first plate and the second plate is 30°-60°; in each composite plate, the number of the first plate and the second plate is not less than 4; the diameter of the ribs of the first plate and the second plate is 0.32-0.4mm.

[0010] Furthermore, the cross-sectional area of ​​the reaction channel is 50-100 mm2, the length is 20-60 mm, and a heating component is provided on the side wall.

[0011] Secondly, embodiments of the present invention also provide a design method for a SiC reactor for the ammonium oximeation of cyclohexanone, the method comprising: Determine the preset plate shape and preset hole shape of the first plate and the second plate, and obtain a variety of plate shape-hole shape combination structures based on the preset plate shape and preset hole shape; Based on the plate-hole combination structure, the spatial range of the reactor's computational domain, as well as the physical dimensions of the core reaction zone and the fluid guiding section, are determined, and the thermal boundary and the conjugate heat transfer boundary of the fluid-solid interface are defined. The spatial extent of the reactor computational domain is divided into grids, and the grid size gradient is determined in order to perform numerical modeling of the reactor computational domain; Based on the numerical modeling results, coupled control equations and physical models for flow, heat transfer, mass transfer and chemical reaction are established to construct a fully coupled numerical system for solution. Based on the numerical system of the fully coupled solution, the target parameters of the reactor are parametrically scanned and optimized to determine the optimal parameter values ​​of the plate-pore combined structure. The optimal parameter values ​​of the plate-hole combination structure were verified by performance simulation to obtain the optimal plate-hole combination structure. Based on the optimal plate-hole combination structure, a SiC reactor was designed.

[0012] Further, determining the preset plate shape and preset hole shape of the first plate and the second plate includes: The first plate and the second plate are determined to be either flat plates or corrugated plates. The shapes of the plurality of first through holes opened on the first plate and the plurality of second through holes opened on the second plate are determined to be one of triangle, square, rhombus and hexagon.

[0013] Furthermore, the opening structure of the first plate is determined based on the principle of two-dimensional periodic array arrangement; The first plate is periodically bent using a sine curve mathematical function to obtain the second plate.

[0014] Further, the step of meshing the spatial range of the reactor computational domain and determining the mesh size gradient includes: The reactor computational domain is divided into an unstructured mesh based on polyhedral elements to obtain the initial mesh structure; Sensitivity analysis was performed on the initial mesh structure to obtain the region gradient partitioning results; Based on the region gradient partitioning results, the region cell size and mesh growth rate are determined; Based on the region unit size and the mesh growth rate, the core reaction region is refined to obtain a refined mesh region. The global mesh parameters are integrated based on the refined mesh region to determine the mesh size gradient.

[0015] Furthermore, the area unit size includes a first unit size and a second unit size, the first unit size being 0.008~0.012mm, the second unit size being 0.17~0.19mm, and the mesh growth rate being 1.0~1.2.

[0016] Further, the optimal parameter values ​​of the plate-hole combination structure are verified through performance simulation to obtain the optimal plate-hole combination structure, including: The optimal parameter values ​​of the plate-hole combined structure were simulated to obtain velocity cloud map, temperature cloud map and product concentration cloud map; Based on the velocity cloud map, temperature cloud map, and product concentration cloud map, flow field, temperature field, and concentration field analysis are performed to obtain the analysis results. Based on the analysis results, the optimal plate-hole combination structure is determined.

[0017] Compared with the prior art, the present invention has the following advantages: The present invention discloses a SiC reactor for the ammonium oxime formation of cyclohexanone. The reactor employs silicon carbide flat plates and corrugated plates arranged alternately along the axial direction of the reaction channel and fitted with a diamond-shaped through-hole structure. This structure can agitate the fluid within the reaction channel, improving the radial diffusion effect and extending the effective residence time of the fluid. Based on the excellent thermal conductivity of silicon carbide and the combined plate structure, the heat exchange between the wall and the fluid is enhanced, optimizing the temperature field distribution within the channel. This facilitates improved mass and heat transfer conditions, thereby enhancing the formation of cyclohexanone oxime.

[0018] This invention discloses a design method for a SiC reactor for the ammonium oxime process of cyclohexanone. The optimal configuration is determined by screening and simulation iteration through multiple combinations of plate-type composite plates and composite plate pore types. The structural parameters are precisely optimized by numerical modeling and multi-field coupled simulation. The internal flow channels of the formed composite plate SiC reactor can moderately disturb the fluid, which is conducive to improving the radial mixing degree of reactants and improving the molecular diffusion effect. At the same time, the distribution of fluid-solid heat transfer interface is optimized, which improves the heat transfer capacity of the cavity to a certain extent and steadily improves the reaction conversion performance of the ammonium oxime process of cyclohexanone.

[0019] Based on the above reasons, this invention can be widely applied in fields such as chemical reactors. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a front view of a SiC reactor for the ammonium oximeation of cyclohexanone according to the present invention; Figure 2 This is a schematic diagram of the reaction channel and composite plate of the present invention; Figure 3 This is a three-dimensional structural diagram of the composite plate of the present invention; Figure 4 This is a schematic flow diagram of a SiC reactor design method for the ammonium oximeation of cyclohexanone according to the present invention. Figure 5 A comparison of flow velocities for different rib diameters for various hole types; Figure 6 A comparison of flow velocities for different orifice types under different plate angles; Figure 7 A comparison of flow rates for different orifice types with different numbers of plate layers; Figure 8 The fluid flow diagrams in the channels of each structure under optimal parameters are shown. Figure 9 The heat transfer diagram of the SiC framework to the fluid in each structure is shown. Figure 10 This is a diagram showing the concentration distribution of the product in each structure.

[0022] In the figure: 1. Reactor shell; 2. Reaction channel; 3. Composite plate; 301. First plate; 3011. First through hole; 302. Second plate; 3021. Second through hole. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0026] Please see Figure 1 , Figure 1 This is a front view of a SiC reactor for the ammonium oximeation of cyclohexanone according to the present invention.

[0027] This application provides an embodiment of the invention that provides a SiC reactor for the ammonium oximeation of cyclohexanone, including a reactor shell 1, multiple reaction channels 2 and multiple composite plates 3.

[0028] Among them, the reactor shell 1, reaction channel 2 and composite plate 3 are all made of silicon carbide. Based on the excellent thermal conductivity and corrosion resistance of silicon carbide, it can improve the mixing uniformity of the fluid inside the reaction channel 2, optimize the distribution of temperature field and product concentration field in the cavity, and help improve the generation efficiency of cyclohexanone oxime.

[0029] Multiple reaction channels 2 are arrayed inside the reactor shell 1, with the axial direction of the reaction channels 2 parallel to the axial direction of the reactor shell 1. The multiple reaction channels 2 can be separated by multiple silicon carbide partitions inside the reactor shell 1. The axial direction of the reaction channels 2 is parallel to the axial direction of the reactor shell 1, which can promote heat transfer between the reaction channels 2, improve the uniformity of the temperature field distribution inside the reactor, and optimize the mixing effect of materials inside the channels.

[0030] Please see Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the reaction channel and composite plate of the present invention. Figure 3 This is a three-dimensional structural diagram of the composite plate of the present invention.

[0031] Multiple composite plates 3 are disposed within multiple reaction channels 2. At least one composite plate 3 can be disposed within each reaction channel 2. The composite plates 3 can agitate the fluid flowing through the inside of the reaction channel 2 to enhance the radial mixing effect of the fluid. The composite plate 3 includes multiple first plates 301 and multiple second plates 302. The first plates 301 and second plates 302 are spaced apart along the axial direction of the reaction channel 2. The first plates 301 and second plates 302 can be stacked, i.e., the first plates 301 and second plates 302 are in contact. The staggered stacking and contact of the first plates 301 and second plates 302 can optimize the flow field distribution inside the reaction channel 2, improve the uniformity of the temperature field and product concentration field inside the reactor, and improve the production efficiency of cyclohexanone oxime.

[0032] The first plate 301 is a flat plate, and the second plate 302 is a corrugated plate. The corresponding edges of the first plate 301 and the second plate 302 have a preset angle. Figure 3 As shown, the angle between the corresponding sides of the first plate 301 and the second plate 302 is β. The angle between the corresponding sides of the first plate 301 and the second plate 302 (i.e., the value of β) can be 30°-60°. By setting the angle between the corresponding sides of the first plate 301 and the second plate 302 to a preset angle, and by spacing and stacking the first plate 301 of the flat plate structure and the second plate 302 of the corrugated plate structure, a tortuous flow channel with axial periodicity can be formed, thereby changing the flow direction of the fluid inside the reaction channel 2, forming local shearing and secondary flow inside the channel, improving the distribution of the flow field, temperature field and product concentration field inside the reaction channel 2, and helping to prolong the effective residence time of the reactants in the channel.

[0033] The first plate 301 has multiple first through holes 3011, and the second plate 302 has multiple second through holes 3021. The multiple first through holes 3011 are arranged in an array on the first plate 301, and the multiple second through holes 3021 are arranged in an array on the second plate 302. The shapes of the first through holes 3011 and the second through holes 3021 are both rhomboid. Based on the high thermal conductivity of silicon carbide material and the high specific surface area of ​​the arrayed reaction channels 2, the heat of reaction can be rapidly and uniformly conducted from the wall of the reaction channel 2 to the fluid core area. The shapes of the first through holes 3011 and the second through holes 3021 are both rhomboid. The rhomboid shape, with its sharp angles, induces a transverse velocity component in the fluid at the corrugated turning points and transition areas between the straight and corrugated sections of the composite plate 3. This transverse velocity component enhances radial heat diffusion and mass transfer within the channel, while simultaneously disrupting the spatial symmetry of the original flow field. This creates a controllable secondary flow and local shearing within the channel, thereby eliminating the axial high-speed core region of the reaction channel 2 and suppressing short-circuit flow. This ensures that the ratio of the actual flow path length of the fluid within the reactor to the geometric length of the reaction channel 2 approaches 1, allowing the reactants sufficient residence time under low-speed flow conditions.

[0034] In some embodiments, each composite plate 3 contains at least four first plates 301 and two plates 302. Multiple first plates 301 and second plates 302 are stacked alternately along the axial direction of the reaction channel 2, which can form a multi-level turbulence structure in the reaction channel 2, facilitating continuous disturbance of the fluid flowing through the channel. There is a preset plate distance between adjacent first plates 301 and second plates 302. This plate distance determines the hydraulic diameter and porosity of the microchannel. The appropriate hydraulic diameter and porosity can optimize the flow state of the fluid inside the reaction channel 2, generate secondary flow and local shear effect, improve the distribution of the flow field, temperature field and product concentration field inside the channel, and help improve the residence effect of reactants in the channel.

[0035] The rib diameter of the first plate 301 and the second plate 302 is 0.32-0.4 mm. The rib diameter is the diameter of the silicon carbide skeleton support rib (i.e., the diameter of the rib between two adjacent first through holes 3011 on the first plate 301 and between two adjacent second through holes 3021 on the second plate 302). The value of the rib diameter can be 0.36 mm. The silicon carbide support rib of this size can provide reliable support for the first plate 301 and the second plate 302. While ensuring the structural strength of the plate, it is easy to maintain the forming size of the reaction channel 2, which is conducive to maintaining a suitable channel porosity and hydraulic diameter, and optimizing the distribution of the flow field, temperature field and product concentration field inside the channel.

[0036] In some embodiments, the cross-sectional area of ​​reaction channel 2 is 50-100 mm². 2The length is 20-60mm, and heating components are provided on the side walls; specifically, the cross-sectional dimensions of reaction channel 2 can be 8mm×8mm, and the cross-sectional area can be 64mm². 2 The cross-sectional dimensions can be matched with the first plate 301 and the second plate 302 inside the channel, which facilitates the formation of a reasonable fluid flow space inside the reaction channel 2. This is beneficial for generating secondary flow and local shear effect during fluid flow, and improving the flow field distribution inside the channel. The axial length can be 40mm, and the reaction zone within the 15-35mm length range inside the reaction channel 2 can be set as the core reaction zone. This core reaction zone is the area where the cyclohexanone ammonium oxime reaction occurs. Heating components are set on the side wall of the core induction zone. The heating components set on the side wall of the core reaction zone can specifically control the temperature of the core reaction zone. Combined with the excellent thermal conductivity of silicon carbide, it is easy to transfer heat evenly to the fluid in the channel, optimize the temperature field and product concentration field inside the core reaction zone, and help improve the formation effect of cyclohexanone oxime.

[0037] The present invention discloses a SiC reactor for the ammonium oxime formation of cyclohexanone. The reactor employs silicon carbide flat plates and corrugated plates arranged alternately along the axial direction of the reaction channel 2, and is equipped with a diamond-shaped through-hole structure. This structure can agitate the fluid within the reaction channel 2, improving the radial diffusion effect and extending the effective residence time of the fluid. Based on the excellent thermal conductivity of silicon carbide and the combined plate structure, the heat exchange between the wall and the fluid is enhanced, optimizing the temperature field distribution within the channel. This facilitates improved mass and heat transfer conditions, thereby improving the formation of cyclohexanone oxime.

[0038] Please see Figure 4 , Figure 4 This is a schematic flow diagram of a SiC reactor design method for the ammonium oximeation of cyclohexanone according to the present invention.

[0039] This invention also provides a design method for a SiC reactor for the ammonium oximeation of cyclohexanone, the method comprising the following steps: Step 101: Determine the preset plate shape of the first plate 301 and the second plate 302 and the preset hole shape of the first plate 301, and obtain a variety of plate shape-hole shape combination structures based on the preset plate shape and the preset hole shape.

[0040] Specifically, the SiC reactor includes a reactor shell 1, multiple reaction channels 2, and multiple composite plates 3. The multiple reaction channels 2 are arrayed inside the reactor shell 1, and the axial direction of the reaction channels 2 is parallel to the axial direction of the reactor shell 1. The multiple composite plates 3 are disposed inside the multiple reaction channels 2. The composite plates 3 include multiple first plates 301 and multiple second plates 302. The first plates 301 and the second plates 302 are spaced apart along the axial direction of the reaction channels 2. The first plates 301 have multiple first through holes 3011, and the second plates 302 have multiple second through holes 3021. The reactor shell 1, the reaction channels 2, and the composite plates 3 are all made of silicon carbide.

[0041] Using various plate-hole combination structures as test objects, the optimal structural form suitable for reaction channel 2 was compared and screened. Different combinations can form different turbulence effects in the channel. The changes in secondary flow, local shear effect, flow field, temperature field, and product concentration field corresponding to each group of schemes can be compared and screened to select the plate combination scheme that is beneficial to improving the cyclohexanone ammonium oxime reaction effect.

[0042] In some embodiments, determining the preset plate shape of the first plate 301 and the second plate 302 and the preset hole shape of the first plate 301 includes: determining that the plate shape of the first plate 301 and the second plate 302 is one of a flat plate or a corrugated plate; and determining that the shape of the plurality of first through holes 3011 opened on the first plate 301 is one of a triangle, a square, a rhombus, and a hexagon.

[0043] Specifically, during the selection phase, the first plate 301 and the second plate 302 can both be flat or corrugated plates, and the shape of the first through hole 3011 can be one of triangle, square, rhombus, and hexagon. Based on the preset plate shape and preset hole shape, various plate-hole combination structures can be obtained as follows: the first plate 301 and the second plate 302 are both flat plates, and the first through hole 3011 and the second through hole 3021 are rhombuses; the first plate 301 is a flat plate, the second plate 302 is a corrugated plate, and the first through hole 3011 and the second through hole 3021 are rhombuses; the first plate 301 is a corrugated plate, the second plate 302 is a flat plate, and the first through hole 3011 and the second through hole 3021 are squares; the first plate 301 and the second plate 302 are both corrugated plates, and the first through hole 3011 and the second through hole 3021 are hexagons.

[0044] The above-mentioned plate-hole combination structures were arranged as test samples in reaction channel 2 for testing. Different combinations can form different fluid disturbance effects inside reaction channel 2. The changes in secondary flow, local shear effect, flow field, temperature field and product concentration field corresponding to each group of structures can be compared, and the plate combination scheme that is conducive to optimizing the cyclohexanone ammonium oxime reaction effect can be screened.

[0045] In some embodiments, the opening structure of the first plate 301 is determined based on the principle of two-dimensional periodic array arrangement; the first plate 301 is periodically bent through a sine curve mathematical function to obtain the second plate 302; the first plate 301 and the second plate 302 are arranged alternately and stacked in the reaction channel 2, which can form a continuously changing flow space inside the reaction channel 2, continuously disturb the fluid inside the channel, facilitate the formation of secondary flow and local shear effect in the flow channel, improve the distribution of flow field, temperature field and product concentration field inside the reaction channel 2, and help prolong the effective residence time of reactants in the channel.

[0046] Step 102: Determine the spatial range of the reactor's computational domain, as well as the physical dimensions of the core reaction zone and the fluid guiding section, and define the thermal boundary and the conjugate heat transfer boundary of the fluid-solid interface.

[0047] The cross-sectional dimensions of the core reaction zone are limited to 8mm × 8mm and the axial length is 40mm. Fluid guide sections with a length of 10mm are set at both ends of the core reaction zone along the axial direction. The sidewalls corresponding to the 15~35mm interval in the core reaction zone are selected as the constant temperature heating walls. The diameter of the reinforcing ribs D, the angle between the plates β, and the number of stacked layers I are defined as the core structural parameters. These structural parameters are used as variables for comparative testing. The parameter changes can change the internal flow space and turbulence structure of the reaction channel 2. The secondary flow and local shear effects corresponding to each set of parameters can be compared, which is convenient for observing the changes in the flow field, temperature field and product concentration field. From this, the parameter combination scheme that is conducive to optimizing the cyclohexanone ammonium oxime reaction effect can be screened.

[0048] Step 103: Mesh the spatial range of the reactor computational domain and determine the mesh size gradient to perform numerical modeling of the reactor computational domain. Using a gradient-changing mesh size to divide the computational domain allows for mesh refinement in areas of abrupt structural changes such as plates and through-holes, improving the accuracy of the numerical model in capturing secondary flow and local shear effects within reaction channel 2. This facilitates the accurate acquisition of simulation data for the flow field, temperature field, and product concentration field.

[0049] In some embodiments, the spatial extent of the reactor computational domain is meshed, and the mesh size gradient is determined, including the following steps: Step 1031: Perform unstructured meshing of the reactor computational domain based on polyhedral elements to obtain the initial mesh structure.

[0050] The reactor was numerically modeled and meshed using COMSOL Multiphysics 6.1 software. Based on the assumptions of incompressibility, steady state, and laminar flow, a fully coupled set of governing equations for flow, heat transfer, mass transfer, and chemical reaction was constructed. Dimensionless parameters such as Reynolds number, Peckley number, Nusselt number, and Sherwood number were introduced as performance evaluation indicators. Polyhedral elements were used to perform unstructured meshing of the entire computational domain, and the mesh size gradient was determined.

[0051] This modeling and meshing method can be adapted to the geometric contours of the first plate 301 and the second plate 302 inside the reaction channel 2, and obtain the variation characteristics of secondary flow and local shear effect in the channel. Based on various dimensionless parameters, the differences in flow field, temperature field and product concentration field corresponding to different plate-hole structures can be quantitatively compared, which is convenient for screening structural schemes that are beneficial to improving the cyclohexanone ammonium oxime reaction effect.

[0052] Step 1032: Perform sensitivity analysis on the initial mesh structure to determine the region cell size and mesh growth rate.

[0053] In some embodiments, the region cell size includes a first cell size and a second cell size, wherein the first cell size is 0.008~0.012mm, the second cell size is 0.17~0.19mm, and the mesh growth rate is 1.0~1.2.

[0054] After completing the mesh sensitivity analysis, for key regions with significant parameter gradient changes, such as the fluid region and the solid structure wall, the size of the first element (i.e., the local minimum mesh element size) was limited to the range of 0.008 mm to 0.012 mm, and the size of the second element (i.e., the maximum mesh element size) was controlled within the range of 0.17 mm to 0.19 mm. Simultaneously, the overall mesh growth rate was configured within the range of 1.0 to 1.2. This gradient mesh configuration scheme can adapt to the structural contours of the first plate 301 and the second plate 302, reducing the numerical calculation deviation of mesh sizes and ensuring the reliability of simulation results for different plate-hole combination structures. Based on the simulation results, structural parameters suitable for the cyclohexanone ammonium oxime reaction were selected.

[0055] Step 1033: Based on the region element size and mesh growth rate, refine the mesh of the core reaction region to obtain the refined mesh region. Refining the mesh of the core reaction region can reduce data deviations caused by numerical calculations and ensure the accuracy of the solutions for the flow field, temperature field, and concentration field.

[0056] Step 1034: Integrate the global mesh parameters based on the refined mesh region to determine the mesh size gradient. Based on the globally integrated mesh size gradient, local fine mesh layout can be achieved on the inner wall of reaction channel 2 and around the irregular structures of the first plate 301 and the second plate 302. This can balance the overall mesh quantity and simulation computation overhead, improve the numerical model's ability to capture secondary flow and local shear effects inside the channel, facilitate the accurate acquisition of simulation data on flow field, temperature field, and product concentration field corresponding to different plate-hole combinations, and help compare and screen the optimal structural parameters suitable for the cyclohexanone ammonium oxime reaction.

[0057] Step 104: Based on the numerical modeling results, establish the coupled control equations and physical models for flow, heat transfer, mass transfer and chemical reaction to construct a fully coupled numerical system for solution.

[0058] Based on the numerical modeling results, key geometric parameters were scanned and optimized according to the criteria of reducing the characteristic average velocity of cyclohexanone, extending the fluid residence time, and enhancing radial mixing. Coupled control equations and physical models of flow, heat transfer, mass transfer, and chemical reaction were established.

[0059] Step 105: Based on the fully coupled numerical solution system, perform parametric scanning and optimization analysis on the target parameters of the reactor to determine the optimal parameter values ​​for the plate-pore combination structure. Adjusting the geometric parameters such as the inter-plate angle, layer height, number of layers, and rib diameter can change the flow channels and turbulence structures formed by the first plate 301 and the second plate 302 inside the reaction channel 2. This allows for comparison of secondary flow and local shear effects corresponding to different parameter combinations. Summarizing the flow field, temperature field, and product concentration field data obtained from each simulation facilitates the selection of the optimal plate-pore combination parameters that are relatively suitable for the cyclohexanone ammonium oxime reaction. Using the parametric scan function of COMSOL Multiphysics 6.1, parametric scan analysis of four key geometric parameters—inter-slab angle, story height, number of stories, and rib diameter—was performed sequentially to determine the optimal parameter values ​​for the slab-hole composite structure.

[0060] Step 106: Perform performance simulation verification on the optimal parameter values ​​of the plate-pore combined structure to obtain the optimal plate-pore combined structure, and design a SiC reactor based on the optimal plate-pore combined structure. The SiC reactor is prepared using the plate-pore structure verified by the optimal parameters. This structure can continuously form a stable secondary flow and local shear effect within the reactor channel, which helps improve the radial mixing effect of the fluid inside the channel, prolongs the residence time of reactants, and is beneficial to improving the mass transfer and reaction performance of the cyclohexanone ammonium oxime process.

[0061] In some embodiments, the optimal parameter values ​​of the plate-hole combination structure are verified by performance simulation to obtain the optimal plate-hole combination structure, including the following steps: Step 1061: Simulate the optimal parameter values ​​of the plate-hole combination structure to obtain velocity cloud map, temperature cloud map, and product concentration cloud map. The generated velocity, temperature, and product concentration cloud maps can intuitively present the details of fluid flow, heat transfer, and component distribution around the first plate 301 and the second plate 302 in the reaction channel 2, which is convenient for quantitatively reading the fluid velocity, temperature, and product concentration data in different regions.

[0062] Step 1062: Analyze the flow field, temperature field, and concentration field based on velocity contour maps, temperature contour maps, and product concentration contour maps to obtain the analysis results. Performing three-field analysis based on multiple types of contour maps allows for a quantitative assessment of the radial mixing level, reactant residence effect, and heat transfer performance corresponding to the current plate-orifice combination, objectively reflecting the influence of geometric parameters on the cyclohexanone ammonium oxime reaction.

[0063] Step 1063: Determine the optimal plate-pore combination structure based on the analysis results. The optimal plate-pore combination structure is determined through multi-field analysis. After being assembled inside the SiC reactor, this structure can form a relatively stable secondary flow and local shearing effect in the reaction channel, which helps to improve the radial mixing efficiency of the fluid, prolong the residence time of the reactants, and improve the mass transfer and reaction effect of the cyclohexanone ammonium oxime process.

[0064] Please see Figure 5 , Figure 6 and Figure 7 ,in, Figure 5 A comparison of flow velocities for different rib diameters for various hole types; Figure 6 A comparison of flow velocities for different orifice types under different plate angles; Figure 7 This is a comparison chart of flow velocities for different orifice types with different numbers of plate layers.

[0065] The number of stacking layers has a unified influence on the flow pattern of three types of structures: flat plate, corrugated plate, and composite plate 3 composed of alternating stacked flat and corrugated plates. The fluid velocity of all three types of structures gradually decreases as the number of stacking layers increases, and the overall working condition is relatively excellent when the number of layers exceeds 4. Among them, the composite plate 3, based on the throttling and turbulence superposition effect brought about by the sandwich structure, can form a stronger flow field disturbance effect when stacked to 8 layers.

[0066] Regarding the inter-plate angle parameter, the sensitivity characteristics of different structures are significantly different: the flat plate is less affected by the change of the angle, and the preferred angle range is 60° to 75°; the fluid velocity of the corrugated plate decreases significantly as the angle increases, and the optimal angle for each hole type fluctuates within the range of 30° to 90°; the composite plate 3 is most sensitive to the change of the inter-plate angle, and the preferred working angle range is 30° to 60°.

[0067] Regarding the rib diameter parameter, different types of plates exhibit different flow velocity variation patterns: the fluid velocity inside the flat plate structure increases significantly with the increase of the rib diameter, and the preferred rib diameter is in the smaller range of 0.24mm to 0.36mm; due to the combined effect of the flow channel bending shape and flow damping, the fluid velocity of the corrugated plate and composite plate 3 gradually decreases with the increase of the rib diameter, and both types of structures can obtain better working performance by using a larger rib diameter greater than 0.32mm.

[0068] Please see Figure 8 , Figure 9 and Figure 10 ,in, Figure 8 The fluid flow diagrams in the channels of each structure under optimal parameters are shown. Figure 9 The heat transfer diagram of the SiC framework to the fluid in each structure is shown. Figure 10 This is a diagram showing the concentration distribution of the product in each structure.

[0069] All three analytical graphs were uniformly selected with L=0 and L=1 / 3. W, L = 2 / 3 Data observations were conducted at four cross sections: W, L=W. Comparison of the flow field, temperature field, and product concentration distribution patterns of different plate-hole configurations revealed that no backflow or eddy current phenomena occurred in the inlet region of any configuration. Therefore, the fluid guide section at the inlet can be eliminated.

[0070] From the perspective of overall reaction performance, the three types of structures show significant differences: the flat plate structure forms a large-scale axial high-speed core area inside, resulting in a weaker radial mixing effect of the fluid, which restricts the heat transfer efficiency and product component distribution; the corrugated plate can effectively weaken the high-speed area of ​​the flow channel, and when combined with diamond-shaped holes, it can achieve a more uniform heat transfer effect; the composite plate 3 can significantly compress the high-speed flow area, promoting the low-speed fluid to spread evenly over a large area in the flow channel, with the shortest heating path and the optimal cyclohexanone product concentration distribution, resulting in a better overall reaction enhancement effect.

[0071] Based on the comprehensive simulation results, it can be determined that the overall performance of composite plate 3 is better than that of flat plate and corrugated plate structures. Among them, the combination configuration of diamond hole with composite plate 3 (with an included angle between plates of 30°~60°, a stacking number of no less than 4 layers, and a rib diameter of 0.32~0.40mm) has a faster heating rate and a more uniform temperature field distribution. At the same time, the yield of cyclohexanone oxime and the uniformity of composition are higher, making it the optimal configuration for SiC reactor.

[0072] This invention discloses a design method for a SiC reactor for the ammonium oxime conversion of cyclohexanone. The optimal configuration is determined through a combination of multiple plate-type composite plates (3-3 pore types) and simulation iteration optimization. Numerical modeling and multi-field coupled simulation are used to precisely optimize structural parameters. The internal flow channels of the formed composite plate 3SiC reactor can moderately disturb the fluid, which is beneficial for improving the radial mixing degree of reactants and enhancing molecular diffusion. Simultaneously, it optimizes the distribution of the fluid-solid heat exchange interface, thereby improving the heat transfer capacity of the cavity to a certain extent and steadily improving the reaction conversion performance of the cyclohexanone ammonium oxime conversion process.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A SiC reactor for the ammonium oximeation of cyclohexanone, characterized in that, include: Reactor shell (1); Multiple reaction channels (2) are arranged in an array inside the reactor shell (1), and the axial direction of the reaction channels (2) is parallel to the axial direction of the reactor shell (1). Multiple composite plates (3) are disposed in multiple reaction channels (2). Each composite plate (3) includes multiple first plates (301) and multiple second plates (302). The first plates (301) and the second plates (302) are spaced apart along the axial direction of the reaction channel (2). Multiple first through holes (3011) are provided on the first plates (301), and multiple second through holes (3021) are provided on the second plates (302). The first plate (301) is a flat plate, the second plate (302) is a corrugated plate, the first through hole (3011) and the second through hole (3021) are both rhomboid in shape, the corresponding sides of the first plate (301) and the second plate (302) have a preset angle, and the reactor shell (1), the reaction channel (2) and the composite plate (3) are all made of silicon carbide.

2. The SiC reactor for the ammonium oximeation of cyclohexanone according to claim 1, characterized in that, A plurality of first through holes (3011) are arranged in an array on the first plate (301), and a plurality of second through holes (3021) are arranged in an array on the second plate (302).

3. A SiC reactor for the ammonium oximeation of cyclohexanone according to claim 1, characterized in that, The angle between the corresponding edges of the first plate (301) and the second plate (302) is 30°-60°; in each composite plate (3), the number of the first plate (301) and the second plate (302) is not less than 4; the diameter of the ribs of the first plate (301) and the second plate (302) is 0.32-0.4mm.

4. A SiC reactor for the ammonium oximeation of cyclohexanone according to claim 1, characterized in that, The cross-sectional area of ​​the reaction channel (2) is 50-100 mm². 2 It has a length of 20-60mm and a heating element is installed on the side wall.

5. A design method for a SiC reactor for the ammonium oxime reaction of cyclohexanone, characterized in that, The method includes: Determine the preset plate type of the first plate (301) and the second plate (302) and the preset hole type of the first plate (301), and obtain a variety of plate type-hole type combination structures based on the preset plate type and the preset hole type; Determine the spatial extent of the reactor's computational domain, as well as the physical dimensions of the core reaction zone and the fluid guiding section; define the thermal boundary and the conjugate heat transfer boundary of the fluid-solid interface. The spatial extent of the reactor computational domain is divided into grids, and the grid size gradient is determined in order to perform numerical modeling of the reactor computational domain; Based on the numerical modeling results, coupled control equations and physical models for flow, heat transfer, mass transfer and chemical reaction are established to construct a fully coupled numerical system for solution. Based on the numerical system of the fully coupled solution, the target parameters of the reactor are parametrically scanned and optimized to determine the optimal parameter values ​​of the plate-pore combined structure. The optimal parameter values ​​of the plate-hole combination structure were verified by performance simulation to obtain the optimal plate-hole combination structure. Based on the optimal plate-hole combination structure, a SiC reactor was designed.

6. The design method of a SiC reactor for the ammonium oxime reaction of cyclohexanone according to claim 5, characterized in that, The process of determining the preset plate shape and preset hole shape of the first plate (301) and the second plate (302) includes: The plate type of the first plate (301) and the second plate (302) is determined to be either a flat plate or a corrugated plate; The shape of the plurality of first through holes (3011) opened on the first plate (301) is determined to be one of the following: triangle, square, rhombus and hexagon.

7. The design method of a SiC reactor for the ammonium oxime reaction of cyclohexanone according to claim 6, characterized in that, The opening structure of the first plate (301) is determined based on the principle of two-dimensional periodic array arrangement; The first plate (301) is periodically bent using a sine curve mathematical function to obtain the second plate (302).

8. The design method of a SiC reactor for the ammonium oxime reaction of cyclohexanone according to claim 5, characterized in that, The step of dividing the spatial range of the reactor computational domain into a grid and determining the grid size gradient includes: The reactor computational domain is divided into an unstructured mesh based on polyhedral elements to obtain the initial mesh structure; Sensitivity analysis was performed on the initial mesh structure to determine the region cell size and mesh growth rate; Based on the region unit size and the mesh growth rate, the core reaction region is refined to obtain a refined mesh region. The global mesh parameters are integrated based on the refined mesh region to determine the mesh size gradient.

9. The design method of a SiC reactor for the ammonium oxime reaction of cyclohexanone according to claim 8, characterized in that, The area unit size includes a first unit size and a second unit size, the first unit size is 0.008~0.012mm, the second unit size is 0.17~0.19mm, and the grid growth rate is 1.0~1.

2.

10. The design method of a SiC reactor for the ammonium oxime reaction of cyclohexanone according to claim 5, characterized in that, The process of performing performance simulation verification on the optimal parameter values ​​of the plate-hole combination structure to obtain the optimal plate-hole combination structure includes: The optimal parameter values ​​of the plate-hole combined structure were simulated to obtain velocity cloud map, temperature cloud map and product concentration cloud map; Based on the velocity cloud map, temperature cloud map, and product concentration cloud map, flow field, temperature field, and concentration field analysis are performed to obtain the analysis results. Based on the analysis results, the optimal plate-hole combination structure is determined.

Images