A gap fixed bed reactor and its method of use

Abstract

The application provides a gap type fixed bed reactor and an application method thereof, and belongs to the technical field of chemical reaction or treatment devices.The application realizes double-channel heat exchange in the gap channel of the gap type fixed bed reactor, accurately controls the radial width of the gap channel when amplification, keeps good heat exchange efficiency and mass transfer performance, realizes amplification of the fixed bed reactor by volume order without affecting reaction conversion rate and selectivity, realizes series connection of multiple reactions through vertical cutting of the reactor axial direction to fill different kinds of catalysts, improves production efficiency, realizes quick replacement of catalysts through axial cutting of the reactor to fill catalysts in different zones, is simple to operate, is suitable for gas-solid, liquid-solid, gas-liquid-solid, liquid-liquid and other heterogeneous systems, and is suitable for fields such as hydrogenation reduction, oxidation, ozonation, carbonylation, CO2 fixation and resource utilization, hydrogen storage-hydrogen release, wastewater treatment and the like, and is a kind of reactor with good general performance.

Description

Technical Field

[0001] This invention belongs to the technical field of chemical reaction or treatment equipment, and particularly relates to an intermittent fixed-bed reactor and its application method. Background Technology

[0002] In industrial production of petroleum, pharmaceuticals, pesticides, materials, and fine chemicals, solid-phase catalysts or reagents are often packed into fixed-bed reactors to form a stacked bed of a certain height or thickness. Gaseous materials, liquid materials, or gas-liquid two-phase materials are transported into the stacked bed and flow through the gaps between or within the solids to achieve a heterogeneous reaction process.

[0003] Existing fixed-bed reactors are mainly axial fixed-bed reactors, which are simple in structure, easy to maintain, and suitable for continuous production. However, they have the following disadvantages: When scaling up the equipment to meet production throughput requirements, the reactor size is usually increased. However, excessive axial height of the reactor will lead to excessive pressure drop when the fluid flows through the bed. Increasing the reactor diameter will reduce the heat exchange area and generate radial temperature difference, which will not only affect reaction efficiency, selectivity, and catalyst life, but also easily lead to safety risks such as runaway temperature. More importantly, after the equipment is scaled up, the uniform distribution of gas and liquid in the radial and axial directions of the catalyst bed is crucial, and the problem of uneven distribution is particularly prominent in large industrial reactors.

[0004] Patent CN201410563140.X improves the uniformity of gas-liquid distribution by setting up a layered gas-liquid distribution plate and catalyst bed, and adds annular baffles to the catalyst bed to improve the gas-liquid distribution within the catalyst bed, thus achieving an increase in reaction efficiency with the same catalyst loading. However, the layered design of the catalyst bed and the addition of annular baffles increase the difficulty of catalyst loading, unloading, and replacement. Furthermore, the layered design does not consider radial heat transfer inside the reactor, and cannot effectively solve problems such as temperature run-off caused by low heat exchange efficiency for reactions with high exothermic activity.

[0005] Patent CN201711421857.0 uses a spiral plate fixed bed reactor to increase the heat transfer coefficient of the reactor shell side, thereby increasing the overall heat transfer coefficient and enhancing heat transfer efficiency and reducing the heat transfer temperature difference. However, the device is complex to manufacture, and the multi-layer design makes it difficult to replace the catalyst, resulting in high maintenance costs. Furthermore, this reactor can only meet the needs of gas-solid phase reactions and has low applicability to gas-liquid-solid three-phase reactions.

[0006] Patent CN202110811847.8 employs a U-shaped groove structure and annular groove structure to construct annular channels. Catalyst is loaded into some of these channels, while adjacent channels preheat the gas and enhance heat transfer of the catalyst loading layer, thereby improving reaction efficiency and heat exchange efficiency. However, it requires the use of ribs to fix the reaction device and a gas diffuser to mitigate gas impact, resulting in a complex device structure, difficulty in catalyst replacement, and poor applicability to gas-liquid-solid three-phase reactions.

[0007] Therefore, it is of great significance to develop new fixed-bed reactors to address the problems of poor heat transfer efficiency during large-scale scale-up, cumbersome catalyst loading, uneven gas-liquid phase distribution, and poor applicability to gas-liquid-solid three-phase systems. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes an intermittent fixed-bed reactor and its application method, which is simple to operate, has low maintenance costs, controllable pressure drop, high heat and mass transfer efficiency during large-scale scale-up, and is applicable to gas-solid, liquid-solid, and gas-liquid-solid multiphase reaction systems.

[0009] To achieve the above objectives, the present invention provides an intermittent fixed-bed reactor and its application method.

[0010] A multi-gap fixed-bed reactor includes an inner cylinder, a middle cylinder, and an outer cylinder, wherein the inner cylinder, the middle cylinder, and the outer cylinder have the same shape; from the inside out, they are the inner cylinder, the middle cylinder, and the outer cylinder; and gap channels exist between the inner cylinder and the middle cylinder.

[0011] The interstitial channels are used to fill solid catalysts (such as Raney nickel, Pd / C, solid acids, or solid bases) or inert supports. The inert supports can also be glass beads, quartz sand, silica microspheres, polystyrene microspheres, or foamed metals with uniform particle size or narrow particle size distribution. Their function is to act as fillers; due to the good uniformity of particle size and packing density, they can form dense, narrow channels with consistent channel widths, providing pathways for fluid flow. This greatly enhances mass transfer in heterogeneous systems such as gas-liquid two-phase and liquid-liquid two-phase systems, achieving excellent mixing effects. This overcomes the limitation of reaction rate on mass transfer efficiency, significantly improving the efficiency of heterogeneous reactions.

[0012] One advantage of this invention is that it provides a scalable interstitial fixed-bed reactor. By setting an interstitial structure to control the radial width of the catalyst bed, the specific surface area of ​​the catalyst bed is kept consistent and does not decrease as the catalyst packing volume increases during scale-up. This avoids problems such as radial temperature differences in the catalyst bed during scale-up, which can lead to runaway temperatures and other difficulties in precise heat control. It also eliminates problems such as reduced mass transfer efficiency during scale-up, affecting reaction conversion and selectivity. Heat exchange occurs through a heat exchange fluid within the inner cylinder, and similarly, heat exchange occurs through the gap between the intermediate cylinder and the outer cylinder.

[0013] Furthermore, the gap channel is provided with an inlet and an outlet for materials.

[0014] Furthermore, a material premixer or distributor is provided at the material inlet to achieve enhanced mixing of multiphase materials and uniform entry into the catalyst bed.

[0015] Furthermore, the mixer and distributor are of at least one type: a T-type microchannel mixer, a Y-type microchannel mixer, a multi-cross microchannel mixer, or a porous mixer constructed by sintering or stacking porous structural materials. The width and height of the mixing passage and the passage formed by material stacking are 50 μm-5.0 cm, preferably 300 μm-2.0 cm. This invention enhances the mixing efficiency of homogeneous or heterogeneous systems such as gas-gas, gas-liquid, and liquid-liquid before entering the catalyst bed by using T-type microchannel mixers, Y-type microchannel mixers, multi-cross microchannel mixers, and porous mixers. It also utilizes these mixers to uniformly distribute and transport materials to the channels filled with the catalyst bed, avoiding the problem of uneven material distribution in the catalyst bed during large-scale scaling.

[0016] Furthermore, the fixed-bed reactor is divided into several sections along an axis perpendicular to the reactor. Different catalysts can be filled in each section for multiple reactions to be carried out in series. The heights can be equal or unequal. Adjacent sections are separated by perforated partitions or screens with pore sizes smaller than the catalyst or inert support particle size to prevent catalyst or inert support loss and mixing within different sections, which could affect reaction conversion and selectivity. The number of sections is 1-100, preferably 1-10.

[0017] Furthermore, the reactor is divided along its axial direction to obtain multiple units, each of which can be independently and quickly loaded and unloaded, allowing for easy and convenient catalyst replacement. The number of units ranges from 1 to 10,000, preferably from 1 to 300, and each unit has the same size.

[0018] Furthermore, the fixed-bed reactor is divided into multiple units along its axial direction. Each unit is separated by a perforated baffle or screen with a diameter smaller than the catalyst particle size but without affecting material dispersion and mass transfer, and is equipped with a handle. When replacing the catalyst, each unit can be directly lifted out for unloading and loading under an inert atmosphere, greatly simplifying catalyst replacement operations in production applications and ensuring safety during catalyst replacement. In addition to the traditional monolithic packing method, the catalyst of this invention can be filled by cutting it into multiple units along the reactor's axial direction, separated by perforated baffles or screens. This allows for easy extraction and replacement, facilitating disassembly, maintenance, and catalyst replacement, and reducing the impact of daily maintenance and catalyst replacement on production progress.

[0019] This invention achieves a magnitude-scale increase in reaction flux by proportionally increasing the radial dimension of an intermittent fixed-bed reactor while maintaining a constant specific surface area, while maintaining consistent reaction conversion rate and product selectivity. Multiple intermittent fixed-bed reactors can also be connected in series or parallel for large-scale scaling, and the output can be flexibly adjusted as needed.

[0020] Furthermore, the present invention does not limit the shape of the cylinder of the fixed bed reactor. It can be any shape of a fixed bed reactor commonly used in the art. For example, the shape of the cylinder (including the inner cylinder, the middle cylinder and the outer cylinder) of the fixed bed reactor can be one of the following: circular, square, rectangular, rhomboid, triangular, gear-shaped, corrugated, fin-shaped and threaded. It is preferred to be circular, square, rectangular or gear-shaped.

[0021] The present invention does not limit the material of the shell of the fixed bed reactor. Any material commonly used in fixed bed reactors in the field can be used. For example, the material of the shell of the fixed bed reactor (including the inner shell, the middle shell and the outer shell) is at least one of stainless steel, Hastelloy, tantalum, zirconium, silicon carbide and glass.

[0022] Furthermore, the radial width and height of the gap channel are adjustable as needed, and the radial width and height determine the catalyst bed filling volume. The radial width of the gap channel is 0.1-10cm, preferably 0.3-3cm; the narrower the radial width, the larger the specific surface area, that is, the larger the surface area per unit filling volume, which is equivalent to a large heat exchange area, allowing for precise temperature control during the reaction process and preventing uncontrollable exothermic reactions and production hazards such as material overflow. However, if the width is too narrow, the reactor filling volume will be too small, making scale-up impossible or the cost of scale-up equipment too high. If the width is too large, it will lead to a decrease in specific surface area, poor heat exchange effect, and a significant scale-up effect, resulting in a deterioration in the reaction effect after scale-up. At the same time, the reaction temperature control will deteriorate, easily leading to uneven temperature distribution inside the reaction liquid and the generation of hot spots and other hazards.

[0023] When scaling up, the radial width of the interstitial channel changes by 50%-1000% of the original width, preferably 80%-600%; the axial height changes by 50%-20000% of the original width, preferably 80%-15000%. For example, when the radial width is 50% of the original width but the axial height is 1000% of the original height, as long as the total volume increases, this increase in reactor volume constitutes reaction scale-up.

[0024] Furthermore, heat exchange occurs on both sides of the gap channel, with the direction of the heat exchange fluid inside the gap channel being the same as or opposite to the direction of material flow; or a baffle is installed in the heat exchange pipe inside the gap channel to form a U-shaped channel so that the heat exchange fluid enters from the top and exits from the top or enters from the bottom and exits from the bottom, with the direction of the heat exchange fluid outside the gap channel being the same as or opposite to the direction of material flow.

[0025] Another advantage of this invention is that by setting heat exchange fluid channels on both sides of the catalyst bed, heat exchange during the reaction process is enhanced, heat exchange efficiency is improved, the temperature of any area of ​​the catalyst bed is precisely controlled, and the accumulation of heat to generate hot spots that affect reaction selectivity and process safety is avoided.

[0026] The intermittent fixed-bed reactor described herein is used in gas-gas, gas-liquid, gas-solid, liquid-solid, gas-liquid-solid, and liquid-liquid mass transfer processes, such as hydrogenation reduction, oxidation, ozonation, carbonylation, CO2 immobilization and resource utilization, hydrogen storage-dehydrogenation, and wastewater treatment.

[0027] The application method of the intermittent fixed bed reactor involves connecting multiple intermittent fixed bed reactors in series or in parallel for large-scale scaling. When connected in series, multiple intermittent fixed bed reactors are directly connected to the material inlet and outlet in sequence according to modular assembly. When connected in parallel, they can be connected according to modular assembly, or multiple cylinders can be connected in parallel to share a set of material premixer or distributor, simplifying equipment complexity.

[0028] Furthermore, the intermittent fixed-bed reactor of the present invention includes an intermittent channel for catalyst filling, an inner heat exchange channel (for heat exchange fluid inlet and outlet), an outer channel (for heat exchange fluid inlet and outlet), an inlet and outlet for the reactants, and a distributor or premixer for uniformly introducing the reactants into the intermittent channel.

[0029] Compared with the prior art, the present invention has the following advantages and technical effects:

[0030] In the multi-gap fixed-bed reactor of this invention, to ensure that the reactants enter the gap channels uniformly, the inlet pipe is made to have the same cross-sectional shape as the gap channels by means of a diameter change. A grid-like cross-mixing passage is set within this diameter-changing channel to distribute the single inlet into multiple inlets, allowing the catalyst to enter the catalyst-packed bed uniformly within the gap channels. Alternatively, a porous structure or inert ceramic balls can be filled within the diameter-changing channel to allow the reactants to undergo multiple cross-mixing processes within the narrow channel, forming a uniform distribution before entering the catalyst-packed bed within the gap channels.

[0031] In the multi-gap fixed-bed reactor of this invention, in order to ensure good heat exchange efficiency during the reaction process, inlet and outlet channels for heat exchange fluid are provided in the inner cylinder that constitutes the gap channels, and inlet and outlet channels for heat exchange fluid are provided on the outside of the outer cylinder, so as to realize dual-channel heat exchange, ensure that the heat exchange area is proportionally increased when the catalyst filling volume of the gap channels is increased, the specific surface area remains unchanged, and avoid the scale-up effect.

[0032] In the multi-gap fixed-bed reactor of this invention, in order to realize the flexible application of the fixed-bed reactor, it is divided along the axial direction perpendicular to the reactor and separated by perforated baffles or screens. Different catalysts are filled in each section to carry out multi-step reaction and post-reaction treatment in series, so as to realize the flexible adjustment of the same raw materials to prepare different or complex products under different catalyst conditions.

[0033] In the multi-gap fixed-bed reactor of this invention, in order to achieve easy operation of catalyst loading in the fixed-bed reactor, it is divided along the axial direction of the reactor and separated by perforated baffles or screens without affecting the diffusion and mixing of reactants in the reactor. The separated units can be easily extracted and replaced, which facilitates catalyst loading and unloading and reduces the impact of daily maintenance and catalyst replacement on production progress.

[0034] In the multi-gap fixed-bed reactor of this invention, in order to achieve large-scale scaling of the intermittent fixed-bed reactor, in addition to increasing the radial dimension of the reactor proportionally while keeping the specific surface area constant, multiple intermittent fixed-bed reactors can also be connected in series to achieve large-scale scaling, and the output can be flexibly adjusted according to demand.

[0035] In summary, the intermittent fixed-bed reactor of this invention implements dual-channel heat exchange inside and outside the intermittent channels. During scale-up, precise control of the radial width of the intermittent channels maintains good heat exchange efficiency and mass transfer performance, achieving a volumetric scale-up of the intermittent fixed-bed reactor without affecting reaction conversion and selectivity. Multiple cross-type microchannel mixers or porous structure mixers are used to achieve premixing of heterogeneous systems and uniform material distribution within the catalyst bed. Different types of catalysts are segmented and filled by cutting perpendicular to the reactor axis, enabling the series connection of multiple reactions and improving production efficiency. The axial cutting of the reactor also allows for rapid catalyst replacement and simplifies operation. The intermittent fixed-bed reactor of this invention is suitable for heterogeneous systems such as gas-solid, liquid-solid, gas-liquid-solid, and liquid-liquid reactions, including hydrogenation reduction, oxidation, ozonation, carbonylation, CO2 immobilization and resource utilization, hydrogen storage-desorption, and wastewater treatment. It is a versatile reactor with good performance. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 A schematic diagram of catalyst loading, reactant inlet and outlet, and shell configuration for an intermittent fixed-bed reactor;

[0038] Figure 2 The diagram shows the heat exchange fluid configuration for an intermittent fixed-bed reactor. In 2-a, the inner heat exchange fluid enters from the top and exits from the bottom, while the outer heat exchange fluid enters from the bottom and exits from the top. In 2-b, a U-shaped channel is formed by baffles, allowing the inner heat exchange fluid to enter from the top and exit from the top, while the outer heat exchange fluid enters from the bottom and exits from the top.

[0039] Figure 3 The diagram shows the cross-sectional shape of an intermittent fixed-bed reactor. 3-a shows a circular fixed-bed reactor body, 3-b shows a triangular fixed-bed reactor body, 3-c shows a square fixed-bed reactor body, and 3-d shows a gear-shaped fixed-bed reactor body.

[0040] Figure 4 This is a schematic diagram of a segmented fixed-bed reactor divided along a direction perpendicular to the axial direction.

[0041] Figure 5 A schematic diagram showing the axial division of an intermittent fixed-bed reactor;

[0042] Figure 6The diagram below shows the structure of the intermittent fixed-bed reactor in Example 1. 6-a is a longitudinal section of the reactor, and 6-b is a transverse section of the reactor. Wherein, 1--material inlet, 2--material outlet, 3--inlet of the heat exchange fluid in the inner layer of the intermittent channel, 4--outlet of the heat exchange fluid in the inner layer of the intermittent channel, 5--inlet of the heat exchange fluid in the outer layer of the intermittent channel, 6--outlet of the heat exchange fluid in the outer layer of the intermittent channel, 7--perforated sieve plate or screen, 8--catalyst packing layer, 9--inner cylinder, 10--middle cylinder, 11--outer cylinder, 12--mixer / distributor integration, 13--diameter of the inner cylinder, 14--diameter of the middle cylinder, 15--diameter of the outer cylinder, 16--intermittent channel, 17--inner heat exchange fluid channel, 18--outer heat exchange fluid channel;

[0043] Figure 7 The diagram shows the structure of the fixed-bed reactor in Comparative Example 1. 7-a is a longitudinal section of the reactor, and 7-b is a transverse section of the reactor. Wherein, 1--material inlet, 2--material outlet, 3--outer heat exchange fluid inlet, 4--outer heat exchange fluid outlet, 5--porous channel mixer, 6--perforated sieve plate or screen, 7--catalyst packing layer, 8--inner cylinder, 9--outer cylinder, 10--diameter of the inner cylinder, 11--diameter of the outer cylinder, 12--heat exchange channel. Detailed Implementation

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0046] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0047] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0048] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0049] In the embodiments of this invention, the raw materials, catalysts, solvents, etc., were all obtained through purchase.

[0050] A schematic diagram of catalyst loading and reactant inlet / outlet of the intermittent fixed-bed reactor of this invention is shown below. Figure 1 ;

[0051] Schematic diagrams of the heat exchange fluid arrangement of the intermittent fixed-bed reactor in some embodiments of the present invention are shown below. Figure 2 ;

[0052] Schematic diagrams of the cross-sectional shape of the intermittent fixed-bed reactor of some embodiments of the present invention are shown below. Figure 3 ;

[0053] A schematic diagram of the intermittent fixed-bed reactor of some embodiments of the present invention, divided along a line perpendicular to the axial direction, is shown below. Figure 4 ;

[0054] A schematic diagram of the axially segmented intermittent fixed-bed reactor of some embodiments of the present invention is shown below. Figure 5 .

[0055] In some embodiments of the present invention, the mixer and distributor are at least one of the following types: T-type microchannel mixer, Y-type microchannel mixer, multi-cross microchannel mixer, and porous mixer constructed by sintering or stacking porous structural materials. The width and height of the mixing passage and the passage formed by material stacking are 50 μm-5.0 cm, preferably 300 μm-2.0 cm. The present invention enhances the mixing efficiency of homogeneous or heterogeneous systems such as gas-gas, gas-liquid, and liquid-liquid before entering the catalyst bed by setting T-type microchannel mixers, Y-type microchannel mixers, multi-cross microchannel mixers, and porous mixers. It also utilizes these mixers to uniformly distribute and transport materials to the channels filled with the catalyst bed, avoiding uneven material distribution in the catalyst bed during large-scale scaling. For example, in some embodiments, "a porous sieve is used to form a cross-distributed porous passage to uniformly mix the reaction liquid and hydrogen before distributing them into the catalyst bed." In reality, the distributor also functions as a mixer.

[0056] Example 1

[0057] A schematic diagram of the fixed-bed reactor structure in this embodiment is shown below. Figure 6 The reactor is connected by concentric circles of the inner cylinder 9, the intermediate cylinder 10, and the outer cylinder 11, with the upper and lower sections connected by welding or flanges. The inner cylinder 9 and the intermediate cylinder 10 are separated by a gap channel 16. The lower end of the gap channel 16 is connected by a perforated sieve plate or screen 7. During catalyst filling, 1 cm of 80-mesh quartz sand is first filled, followed by Raney nickel catalyst, and then another 1 cm of 80-mesh quartz sand is placed on top. The lower end of the gap channel 16 is the material inlet 1, and the upper end is the material outlet 2, both connected by a conical structure. The center of the cone is either the inlet or outlet. The cone connecting the inner cylinder 9 and the intermediate cylinder 10 also forms a gap channel. Inside this channel, a grid-crossing mixing passage is arranged as a mixer for the gas-liquid two-phase materials, and also serves as a material distributor, ensuring uniform mixing of the gas and liquid phases within the grid-crossing mixing passage while maintaining a consistent material ratio at any point entering the gap channel 16. Two inner heat exchange fluid inlets 3 are symmetrically arranged on both sides of the material outlet position at the center of the cone, penetrating the cone gap channel but not connected to the inside of the cone. The two heat exchange fluid inlets 3 are located close to the material outlet 1 to avoid affecting the material distribution consistency due to being too close to the gap channel 16 filled with catalyst. Similarly, two inner heat exchange fluid outlets 4 are symmetrically arranged on both sides of the material inlet 1 at the center of the cone, connected in the same way as the heat exchange fluid inlets 3. The gap between the intermediate cylinder 10 and the outer cylinder 11 is the outer heat exchange fluid channel 18. A serpentine baffle is installed in the channel to avoid dead zones in the heat exchange fluid flow. The outer heat exchange fluid inlet and outlet have one upper end and one lower end, forming a 180° angle with the left and right sides.

[0058] Nitro reduction reaction

[0059] p-Chlorotibene was selected as the substrate, methanol as the solvent, hydrogen was used at a rate of 3 equivalents, the reaction pressure was 2.5 MPa, the reaction temperature was 70℃, and the reactor shell was circular (e.g., Figure 3 (3-a) The reactor dimensions are as follows: the inner diameter of the interstitial channel is 10 cm (referring to the diameter of the inner cylinder), the outer diameter of the interstitial channel is 12 cm (referring to the diameter of the middle cylinder), the width of the catalyst-fillable interstitial channel is 1 cm, the height is 29 cm, the volume is 1 L, the catalyst is Raney nickel, and the reaction residence time is 2 min. The flow direction of the reaction liquid and hydrogen is from bottom to top, the flow direction of the heat exchange fluid in the inner channel is countercurrent from top to bottom, and the flow direction of the heat exchange fluid in the outer channel is cocurrent from bottom to top (e.g., ...). Figure 2 In step 2-a), a grid-cross type mixing pathway is used to uniformly mix the reaction liquid and hydrogen and then distribute them into the catalyst bed, resulting in a reaction conversion rate of 96% and a selectivity of 98%.

[0060] Example 2

[0061] Nitro reduction reaction

[0062] p-Chlorotibene was selected as the substrate, methanol as the solvent, hydrogen was used at a rate of 3 equivalents, the reaction pressure was 2.5 MPa, the reaction temperature was 70℃, and the reactor shell was circular (e.g., Figure 3 (3-a) The reactor dimensions are as follows: inner diameter of the interstitial channel is 10 cm, outer diameter of the interstitial channel is 12 cm, width of the catalyst-filled interstitial channel is 1 cm, height is 29 cm, volume is 1 L, catalyst is Raney nickel, and reaction residence time is 2 min. The reaction liquid and hydrogen flow direction is from bottom to top, the inner heat exchange fluid flow direction is countercurrent from top to bottom, and the outer heat exchange fluid flow direction is cocurrent from bottom to top (e.g., ...). Figure 2 In step 2-a), a porous sieve is used to form a cross-distributed porous channel to uniformly mix the reaction liquid and hydrogen and then distribute them into the catalyst bed, resulting in a reaction conversion rate of 99% and a selectivity of 98%.

[0063] Example 3

[0064] Nitro reduction reaction

[0065] p-Chlorotibene was selected as the substrate, methanol as the solvent, hydrogen was used at a rate of 3 equivalents, the reaction pressure was 2.5 MPa, the reaction temperature was 70℃, and the reactor shell was circular (e.g., Figure 3 (3-a) The reactor dimensions are as follows: inner diameter of the interstitial channel is 10 cm, outer diameter of the interstitial channel is 12 cm, width of the catalyst-filled interstitial channel is 1 cm, height is 29 cm, volume is 1 L, catalyst is Raney nickel, and reaction residence time is 2 min. The reaction liquid and hydrogen flow direction is from bottom to top, the inner heat exchange fluid flow direction is countercurrent from top to bottom, and the outer heat exchange fluid flow direction is cocurrent from bottom to top (e.g., ...). Figure 2 In step 2-a), inert ceramic balls with uniform particle size are selected to form a cross-distributed porous channel to uniformly mix the reaction liquid and hydrogen gas and then distribute them into the catalyst bed. The reaction conversion rate is 98% and the selectivity is 99%.

[0066] Example 4

[0067] Hydrodebenzylation reaction

[0068] The reaction was carried out using benzyl-protected p-bromophenol as the substrate, tetrahydrofuran as the solvent, 3 equivalents of hydrogen gas, a reaction pressure of 3.5 MPa, a reaction temperature of 85 °C, and a square reactor (e.g., [missing information]). Figure 3The reactor (3-c) has the following dimensions: inner layer of the interstitial channel has a side length of 10cm, outer layer of the interstitial channel has a side length of 12cm, the width of the catalyst-filled interstitial channel is 1cm, the height is 23cm, the volume is 1L, the catalyst is 10% Pd / C (purchased from Anaiji Reagent), and the reaction residence time is 3min. The reaction liquid and hydrogen flow direction is from bottom to top, and the inner heat exchange fluid flow direction is from top to top. A U-shaped channel is formed by setting baffles in the inner heat exchange pipe (e.g., ...). Figure 2 In section 2-b), the outer heat exchange fluid flows from bottom to top in a co-current manner. A porous sieve is used to form a cross-distributed porous channel to uniformly mix the reaction liquid and hydrogen before distributing them into the catalyst bed. The reaction conversion rate is 99% and the selectivity is 98%.

[0069] Example 5

[0070] ozone oxidation reaction

[0071] p-Methoxystyrene was selected as the substrate, ethyl acetate as the solvent, 1.5 equivalents of ozone (a mixture of ozone and oxygen, with an ozone concentration of 3.5 mmol / L), a reaction pressure of 0.5 MPa, a reaction temperature of 30 °C, and an equilateral triangular reactor shell (e.g., Figure 3 (3-b) The reactor dimensions are as follows: inner side length of the gap channel is 10cm, outer side length of the gap channel is 12cm, gap channel width is 0.86cm, height is 52.5cm, volume is 1L, the gap channel is filled with inert ceramic balls with a particle size of 500μm, and the reaction residence time is 1min. The reaction liquid and ozone-oxygen mixture flow from bottom to top, the inner heat exchange fluid flows from top to top, a U-shaped channel is formed by baffles in the inner heat exchange pipe, and the outer heat exchange fluid flows from bottom to top in a co-current manner (e.g., ...). Figure 2 In step 2-b), a grid-cross type mixing pathway was used to uniformly mix the reaction liquid and the ozone-oxygen mixture and then distribute it into the inert ceramic ball filling layer. The reaction conversion rate was 98% and the product selectivity for methoxybenzaldehyde was 94%.

[0072] Example 6 (Enlarged Size)

[0073] Nitro reduction reaction

[0074] p-Chlorotibene was selected as the substrate, methanol as the solvent, hydrogen was used at a rate of 3 equivalents, the reaction pressure was 2.5 MPa, the reaction temperature was 70℃, and the reactor shell was circular (e.g., Figure 3(3-a) The reactor dimensions are as follows: inner diameter of the interstitial channel is 58 cm, outer diameter of the interstitial channel is 60 cm, width of the catalyst-filled interstitial channel is 1 cm, height is 539 cm, volume is 100 L, catalyst is Raney nickel, and reaction residence time is 2 min. The reaction liquid and hydrogen flow direction is from bottom to top, the inner heat exchange fluid flow direction is countercurrent from top to bottom, and the outer heat exchange fluid flow direction is cocurrent from bottom to top (e.g., ...). Figure 2 In step 2-a), a porous sieve is used to form a cross-distributed porous channel to uniformly mix the reaction liquid and hydrogen and then distribute them into the catalyst bed, resulting in a reaction conversion rate of 99% and a selectivity of 98%.

[0075] Example 7 (Series)

[0076] Nitro reduction reaction

[0077] p-Chlorotibene was selected as the substrate, methanol as the solvent, hydrogen was used at a rate of 3 equivalents, the reaction pressure was 2.5 MPa, the reaction temperature was 70℃, and the reactor shell was circular (e.g., Figure 3 In reactor 3-a), three reactors are connected in series. The dimensions are as follows: inner diameter of the interstitial channel is 58 cm, outer diameter is 60 cm, the width of the catalyst-filled interstitial channel is 1 cm, and the height is 135 cm. The total height of the three interconnected interstitial channels is 540 cm, and the total volume is 100 L. The catalyst is Raney nickel, and the residence time is 2 min. The reaction liquid and hydrogen flow from bottom to top, the inner heat exchange fluid flows counter-currently from top to bottom, and the outer heat exchange fluid flows co-currently from bottom to top (e.g., ...). Figure 2 In step 2-a), a porous sieve is used to form a cross-distributed porous channel to uniformly mix the reaction liquid and hydrogen and then distribute them into the catalyst bed, achieving a reaction conversion rate of 99% and a selectivity of 99%.

[0078] Example 8 (divided along the axis perpendicular to the reactor)

[0079] Aromatic aldehyde imineation-imine reduction tandem reaction

[0080] Benzaldehyde was selected as the substrate, phenylethylamine as the reagent (1.1 equivalents), toluene as the solvent, and hydrogen gas (1.5 equivalents). The reaction pressure was 2.0 MPa, the reaction temperature was 40℃, and the reactor was circular (e.g., ...). Figure 3In reactor 3-a), the inner diameter of the interstitial channel is 10 cm, the outer diameter is 12 cm, the width of the catalyst-filled interstitial channel is 1 cm, the height is 29 cm (total height at both ends), and the volume is 1 L. The interstitial channel is divided into upper and lower sections along the axial direction perpendicular to the reactor. The lower section is filled with alkaline resin to catalyze the imine reaction of aromatic aldehydes and phenylethylamine, while the upper section is filled with 5% Pd / C catalyst (purchased from Anaiji Reagent) to catalyze the reduction of imine double bonds. The upper and lower sections are separated by a sieve plate with 15-30 μm pores to prevent diffusion and mixing of the two catalysts. The total residence time is 3 min. The reaction liquid of benzaldehyde and phenylethylamine, as well as hydrogen, flows from bottom to top. The inner heat exchange fluid flows counter-currently from top to bottom, and the outer heat exchange fluid flows co-currently from bottom to top. A grid-cross mixing channel is used to uniformly mix the reaction liquid and hydrogen before distributing them into the catalyst bed. The reaction conversion rate is 97%, and the selectivity is 98%.

[0081] Example 9 (divided along the reactor axis)

[0082] Nitro reduction reaction

[0083] p-Chlorotibene was selected as the substrate, methanol as the solvent, hydrogen was used at a rate of 3 equivalents, the reaction pressure was 2.5 MPa, the reaction temperature was 70℃, and the reactor shell was circular (e.g., Figure 3 (3-a) The reactor dimensions are as follows: inner diameter of the interstitial channel is 10 cm, outer diameter of the interstitial channel is 12 cm, width of the catalyst-filled interstitial channel is 1 cm, height is 29 cm, volume is 1 L, catalyst is Raney nickel, and reaction residence time is 2 min. The interstitial channel is divided into six equal sections along the reactor's axial direction. Each section is separated on both sides by a sieve plate with 15-30 μm pores to prevent catalyst diffusion and mixing between adjacent ends. The bottom of each section is also separated by a sieve plate with 15-30 μm pores, facilitating rapid extraction from the interstitial channel for catalyst replacement (each section is filled with the same catalyst). The purpose is that the sieve plates on both sides and the bottom effectively separate the sections, making them independent and allowing for direct extraction from the top for convenient catalyst unloading and replacement. Without this separation, the reactor would have to be disassembled at both ends, requiring tools to push the catalyst out, which is prone to adhesion to the reactor walls, difficult to unload completely, inefficient, and time-consuming. The reaction liquid and hydrogen flow from bottom to top, the inner heat exchange fluid flows counter-currently from top to bottom, and the outer heat exchange fluid flows co-currently from bottom to top. A grid-cross type mixing channel is used to uniformly mix the reaction liquid and hydrogen before distributing them into the catalyst bed. The reaction conversion rate is 98% and the selectivity is 99%.

[0084] Comparative Example 1

[0085] A schematic diagram of the fixed-bed reactor structure in this embodiment is shown below. Figure 7 .

[0086] p-Chlorotibene was selected as the substrate, methanol as the solvent, and hydrogen was used at a rate of 3 equivalents. The reaction pressure was 2.5 MPa, the reaction temperature was 70 °C, and the reactor was a circular channel with an inner diameter of 2 cm, a height of 318 cm, and a volume of 1 L. Raney nickel was used as the catalyst, and the residence time was 2 min. The reaction liquid and hydrogen flowed from bottom to top, while the outer heat exchange fluid flowed counter-currently from top to bottom. A porous sieve was used to form a cross-distributed porous channel to uniformly mix the reaction liquid and hydrogen before they entered the catalyst bed. The reaction conversion rate was 88%, and the selectivity was 90%.

[0087] Comparative Example 2

[0088] p-Chlorotibene was selected as the substrate, methanol as the solvent, hydrogen was used at a rate of 3 equivalents, the reaction pressure was 2.5 MPa, the reaction temperature was 70℃, and the reactor was a circular channel (e.g., Figure 3 (a) The reactor has an inner diameter of 20 cm, a height of 318 cm, and a volume of 100 L. The catalyst is Raney nickel, and the reaction residence time is 2 min. The reaction liquid and hydrogen flow from bottom to top, while the outer heat exchange fluid flows counter-currently from top to bottom. A porous sieve is used to form a cross-distributed porous channel to uniformly mix the reaction liquid and hydrogen before they enter the catalyst bed. The reaction conversion rate is 72%, and the selectivity is 81%.

[0089] Comparative Examples 1 and 2 do not have an intermediate cylinder; they only have two cylinders, with the catalyst inside and the heat exchange fluid outside. Examples 1 and 6 show that when the reactor volume is increased 100 times from 1L to 100L, the reaction maintains a consistent conversion rate and selectivity, indicating that the intermittent fixed-bed reactor has good scalability and avoids scale-up effects. Examples 1 and 7 show that when the reactor volume is increased 100 times from 1L to 100L using three sets in series, the reaction maintains a consistent conversion rate and selectivity, indicating that the intermittent fixed-bed reactor not only has good scalability and avoids scale-up effects but also offers flexible scale-up methods. Furthermore, when scaled up in series, the height of each reactor can be reduced, making it easier to process and maintain during production, thus increasing its practicality. Example 4 shows that the intermittent fixed-bed reactor is also suitable for filling and catalytic reactions with other solid catalysts, demonstrating good versatility. As can be seen from Example 5, in addition to filling with catalyst, the intermittent fixed-bed reactor can also enhance the mass transfer process of gas-liquid two-phase or liquid-liquid immiscible two-phase by filling with inert support, and can be used for heterogeneous reactions such as gas-liquid two-phase reactions.

[0090] Comparative Examples 1 and 2 show that the fixed-bed reactor obtained by simply scaling up the channel size exhibits a significant decrease in reaction conversion and a sharp decline in product selectivity. This is because the reduced specific surface area after size scaling leads to a substantial reduction in the reactor's heat exchange capacity, resulting in an increase in byproducts. This further demonstrates that the designed and developed intermittent fixed-bed reactor has broad application prospects, especially in large-scale production.

[0091] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An intermittent fixed-bed reactor, characterized in that, It includes an inner cylinder, a middle cylinder, and an outer cylinder, wherein the inner cylinder, the middle cylinder, and the outer cylinder have the same shape; from the inside out, they are the inner cylinder, the middle cylinder, and the outer cylinder; there is a gap channel between the inner cylinder and the middle cylinder; The gap channels are used to fill solid catalysts or inert supports; The radial width of the gap channel is 0.1-10cm; The gap channel is provided with a material inlet and an outlet, with the lower end of the gap channel being the material inlet and the upper end being the material outlet; The material inlet is provided with a material premixer or distributor. The type of the mixer and distributor is at least one of T-type microchannel mixer, Y-type microchannel mixer, multi-cross microchannel mixer, and porous mixer constructed by sintering or stacking porous structure materials. The width and height of the passage of the mixer and the passage formed by the material stacking are 50μm-5.0cm. The intermittent fixed-bed reactor is divided into several sections along the axial direction perpendicular to the reactor, with equal or unequal heights. Adjacent sections are separated by perforated baffles or screens with pore sizes smaller than the particle size of the catalyst or inert support. Heat exchange occurs on both sides of the gap channel, with the direction of the heat exchange fluid inside the gap channel being the same as or opposite to the direction of material flow; or a baffle is set in the heat exchange pipe inside the gap channel to form a U-shaped channel so that the heat exchange fluid enters from the top and exits from the top or enters from the bottom and exits from the bottom, with the direction of the heat exchange fluid outside the gap channel being the same as or opposite to the direction of material flow. The application method of intermittent fixed bed reactor is as follows: multiple intermittent fixed bed reactors are connected in series or in parallel for large-scale scaling; when connected in series, multiple intermittent fixed bed reactors are directly connected to the material inlet and outlet in sequence according to modular assembly; when connected in parallel, they are connected according to modular assembly, or multiple cylinders are connected in parallel and share a set of material premixer or distributor.

2. The intermittent fixed-bed reactor according to claim 1, characterized in that, When scaled up, the radial width of the time gap channel changes by 50% to 20,000% of the original width, and the axial height changes by 50% to 20,000% of the original height.

3. The intermittent fixed-bed reactor according to claim 2, characterized in that, When scaled up, the radial width of the time gap channel changes by 50%-1000% of the original width, and the axial height changes by 80%-15000% of the original height.

4. The intermittent fixed-bed reactor according to claim 1, characterized in that, The fixed-bed reactor is divided into multiple units along its axial direction.

5. The application of the intermittent fixed-bed reactor according to any one of claims 1-4 in gas-gas, gas-liquid, gas-solid, liquid-solid, gas-liquid-solid, and liquid-liquid mass transfer.

6. A method of applying the intermittent fixed-bed reactor according to any one of claims 1-4, characterized in that, The multiple intermittent fixed-bed reactors are connected in series or in parallel for large-scale scaling. In series, multiple intermittent fixed-bed reactors are directly connected to the material inlet and outlet in sequence according to modular assembly; in parallel, they are connected according to modular assembly, or multiple cylinders are connected in parallel and share a set of material premixer or distributor.

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