CN117282359A

CN117282359A - Gap type fixed bed reactor and application method thereof

Info

Publication number: CN117282359A
Application number: CN202311358006.1A
Authority: CN
Inventors: 万力; 周长路
Original assignee: East China University of Science and Technology
Current assignee: East China University of Science and Technology
Priority date: 2023-10-19
Filing date: 2023-10-19
Publication date: 2023-12-26

Abstract

The invention provides a gap type fixed bed reactor and an application method thereof, which belong to the technical field of chemical reaction or treatment devices. The reactor is axially cut to realize the series connection of various reactions, the production efficiency is improved, the reactor is axially cut to realize the sectional filling of the catalyst, the quick replacement of the catalyst is realized, the operation is simple, and the reactor is suitable for heterogeneous systems such as gas-solid, liquid-solid, gas-liquid-solid, liquid-liquid and the like, such as hydrogenation reduction, oxidation, ozonization, carbonylation and CO ₂ The method is a reaction with good general performance in the fields of immobilization and resource utilization, hydrogen storage-hydrogen discharge, wastewater treatment and the likeAnd (3) a device.

Description

Gap type fixed bed reactor and application method thereof

Technical Field

The invention belongs to the technical field of chemical reaction or treatment devices, and particularly relates to a gap type fixed bed reactor and an application method thereof.

Background

In industrial production of petroleum, medicine, pesticide, materials, fine chemicals and the like, solid-phase catalysts or solid-phase reagents are often filled in a fixed bed reaction device to form a stacked bed layer with a certain height or thickness, and gas materials, liquid materials or gas-liquid two-phase materials enter the stacked bed layer to flow into a solid or a solid internal gap through conveying, so that a heterogeneous reaction process is realized.

The existing fixed bed reactor mainly takes an axial fixed bed reactor as a main part, has a simple structure, is convenient to maintain and continuously produce, but has the following defects: when the device is enlarged to meet the production flux requirement, the size of the reactor is enlarged, the pressure drop is overlarge when the fluid flows through a bed layer due to the overhigh axial height of the reactor, and the radial temperature difference is generated due to the reduction of the heat exchange area due to the increase of the diameter of the reactor, so that the reaction efficiency, the selectivity and the service life of the catalyst are influenced, and safety risks such as temperature runaway and the like are easy to occur; more importantly, even distribution of the gas and the liquid in the radial direction and the axial direction of the catalyst bed layer after the device is enlarged is very critical, and the problem of uneven distribution is particularly prominent in a large industrial reactor.

The patent CN2014105634140. X improves the uniformity of gas-liquid distribution by arranging the gas-liquid distribution plate and the catalyst bed layer in a layered manner, and the annular baffle plate is additionally arranged on the catalyst bed layer to improve the gas-liquid distribution condition in the catalyst bed layer, so that the improvement of the reaction efficiency is realized under the condition of the same catalyst loading. However, the layered design of the catalyst bed and the addition of the annular baffle plate increase the difficulty of filling, discharging and changing new catalyst, but the layered design does not consider the radial heat transfer in the reactor, and the problems of temperature runaway and the like caused by low heat exchange efficiency can not be effectively solved for the reaction with large heat release.

The patent CN201711421857.0 adopts a spiral plate fixed bed reactor to increase the heat exchange coefficient of the shell side of the reactor, so that the total heat transfer coefficient is increased to strengthen the heat transfer efficiency and reduce the heat transfer temperature difference. However, the device is complex in manufacture, the catalyst is difficult to replace due to the multilayer design, so that the maintenance cost is high, and the reactor can only meet the requirement of gas-solid phase reaction and has low applicability to gas-liquid-solid three-phase reaction.

The patent CN202110811847.8 adopts a U-shaped groove structure and an annular groove structure to construct an annular gap channel, catalyst filling is carried out in part of the channels, gas preheating and heat transfer enhancement of a catalyst filling layer are carried out in the adjacent channels, and the reaction efficiency and the heat exchange efficiency are improved. But the reaction device and the gas expander are required to be fixed by using ribs to slow down the impact force of gas, the device has a complex structure, the catalyst is difficult to replace, and the applicability to gas-liquid-solid three-phase reaction is poor.

Therefore, the development of the novel fixed bed reactor has important significance for solving the problems of poor heat transfer efficiency, tedious catalyst filling, uneven gas-liquid phase distribution, poor applicability of a gas-liquid-solid three-phase system and the like during large-scale amplification in the fixed bed reactor.

Disclosure of Invention

In order to solve the technical problems, the invention provides a gap type fixed bed reactor which is simple to operate, low in maintenance cost, controllable in pressure drop, high in heat and mass transfer efficiency during large-scale amplification and applicable to a gas-solid, liquid-solid and gas-liquid-solid multiphase reaction system and an application method thereof.

In order to achieve the above object, the present invention provides a gap type fixed bed reactor and a method for using the same.

The multi-gap fixed bed reactor comprises an inner layer cylinder body, a middle cylinder body and an outer layer cylinder body, wherein the inner layer cylinder body, the middle cylinder body and the outer layer cylinder body are consistent in shape; the inner layer cylinder, the middle cylinder and the outer layer cylinder are sequentially arranged from inside to outside; a clearance channel exists between the inner layer cylinder and the middle cylinder;

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 carrier can also be glass beads, quartz sand, silica microspheres, polystyrene beads or foam metal with uniform particle size or narrow particle size distribution range, and the inert carrier is used as a filler for filling, and the filler has good particle size uniformity and good bulk density uniformity, so that a path for fluid circulation with compactness, narrow channels and good channel width uniformity can be formed, the mass transfer enhancement of a heterogeneous system of gas-liquid two phases and liquid-liquid two phases can be greatly improved, the good mixing effect is achieved, the limitation of the reaction rate due to the mass transfer efficiency is broken through, and the heterogeneous reaction efficiency is greatly improved.

The invention has the advantages that the gap type fixed bed reactor easy to scale up is provided, the radial width of the catalyst bed layer is controlled by arranging the gap structure, the specific surface area of the catalyst bed layer is kept consistent, the catalyst filling volume is not reduced along with the enlargement of the catalyst filling volume during scale up, the problem that heat such as temperature flying is difficult to accurately regulate and control due to radial temperature difference generated by the catalyst bed layer during scale up is avoided, and the problems that the reaction conversion rate and selectivity are influenced due to the reduction of mass transfer efficiency during the scale up are eliminated. The inner space of the inner cylinder body is used for heat exchange by heat exchange fluid, and the interval between the middle cylinder body and the outer cylinder body is also used for heat exchange by heat exchange fluid.

Further, the gap channel is provided with an inlet and an outlet for material.

Further, a material pre-mixer or a distributor is arranged at the inlet of the material, so that the multi-phase material can be mixed intensively and uniformly enter the catalyst bed.

Further, the mixer and the distributor are at least one of T-type micro-channel mixer, Y-type micro-channel mixer, multi-crossing micro-channel mixer, porous mixer constructed by sintering or stacking porous structure materials, and the width and the height of the passage formed by the passage and the material stacking of the mixer are 50 μm-5.0cm, preferably 300 μm-2.0cm. The invention strengthens the mixing efficiency of homogeneous or heterogeneous systems such as gas, gas-liquid, liquid-liquid and the like before entering the catalyst bed by arranging the T-shaped microchannel mixer, the Y-shaped microchannel mixer, the multi-time cross-shaped microchannel mixer, the porous mixer and the like, and utilizes the mixer to uniformly distribute and convey materials to the channels filled with the catalyst bed, thereby avoiding the problem of uneven distribution of the materials in the catalyst bed during large-scale amplification.

Further, the fixed bed reactor is divided into a plurality of sections along the axial direction perpendicular to the reactor, different catalysts can be filled in each section to carry out series operation of various reactions, the heights are equal or unequal, the adjacent sections are separated by a porous baffle plate or a screen with the aperture smaller than the particle size of the catalyst or the inert carrier, and the loss of the catalyst or the inert carrier and the influence on the reaction conversion rate and the selectivity caused by the mixing of the catalyst or the inert carrier in the different sections are avoided. Wherein the number of the segments is 1-100, preferably 1-10.

Further, a plurality of units are obtained by dividing along the axial direction of the reactor, each unit can be independently and quickly assembled and disassembled, and the catalyst is simply and conveniently replaced. Wherein the number of units is 1-10000, preferably 1-300, and each unit has the same size.

Further, a plurality of units are obtained by dividing along the axial direction of the fixed bed reactor, each unit is separated by a porous baffle plate or a screen which is smaller than the particle size of the catalyst but does not influence material dispersion and mass transfer, and a handle is arranged, when the catalyst is replaced, each unit is directly put forward to discharge and fill the catalyst under an inert atmosphere, so that the catalyst replacement operation in production application is greatly simplified, and the safety of the catalyst during replacement is ensured. Besides the traditional integral stacking filling mode, the catalyst filling mode can be divided into a plurality of units along the axial direction of the reactor, and the units are separated by the porous partition plates or the screens, so that the catalyst can be conveniently extracted and replaced, the disassembly and the maintenance of the device and the replacement of the catalyst are facilitated, and the influence of the daily maintenance of the device and the replacement of the catalyst on the production progress is reduced.

The invention realizes the order-of-magnitude amplification of the reaction flux by increasing the radial size of the gap type fixed bed reactor in proportion and keeping the specific surface area unchanged, simultaneously keeps the consistent reaction conversion rate and product selectivity, can also realize the large-scale amplification of a plurality of gap type fixed bed reactors in series or in parallel, and flexibly adjusts the yield as required.

Further, the shape of the cylinder of the fixed bed reactor is not limited, and is a shape of a fixed bed reactor common in the art, for example, the shape of the cylinder (including an inner cylinder, an intermediate cylinder and an outer cylinder) of the fixed bed reactor can be one of a circle, a square, a rectangle, a diamond, a triangle, a gear shape, a ripple shape, a fin shape and a screw shape, preferably a circle, a square, a rectangle or a gear shape;

the material of the cylinder body of the fixed bed reactor is not limited, and the material is common in the field of fixed bed reactors, for example, the material of the cylinder body (comprising an inner layer cylinder body, a middle cylinder body and an outer layer cylinder body) of the fixed bed reactor is at least one of stainless steel, hastelloy, tantalum, zirconium, silicon carbide and glass.

Further, the radial width and the height of the clearance channel are randomly adjustable according to requirements, and the radial width and the height determine the filling volume of the catalyst bed. The radial width of the clearance channel is 0.1-10cm, preferably 0.3-3cm; the narrower the radial width is, the larger the specific surface area is, namely the larger the surface area per unit filling volume is, which is equivalent to the large heat exchange area, the temperature control in the reaction process is accurate, and the production risks of uncontrollable reaction heat release, flushing and the like can not occur. However, if too narrow, the reactor packing volume is too small to be scalable or the cost of the scaled-up unit is too high. The excessively large reaction temperature can lead to the reduction of the specific surface area, the poor heat exchange effect and the obvious amplification effect, the reaction effect is poor after amplification, the reaction temperature is controlled to be poor, the uneven temperature distribution in the reaction liquid is easy to generate, and the dangers such as hot spots are generated.

The radial width of the gap channel is changed to 50% -1000% of the original width, preferably 80% -600% during large-scale amplification; the axial height change is 50% -20000%, preferably 80% -15000%. For example, when the radial width is 50% of the original, but the axial height is 1000% of the original, it is calculated that the total volume is increased, so that the increase in the reactor volume is a reaction amplification.

Further, heat exchange is carried out on two sides of the clearance channel, and the direction of heat exchange fluid on the inner side of the clearance channel is the same as or opposite to the material flow direction; or a baffle plate is arranged in the heat exchange pipeline at the inner side of the clearance channel to form a U-shaped channel so that heat exchange fluid enters and exits upwards or enters and exits downwards, and the direction of the heat exchange fluid at the outer side of the clearance channel is the same as or opposite to the material flowing direction.

The invention has the advantages that the heat exchange fluid channels are arranged on the two sides of the packed catalyst bed layer, so that the heat exchange in the reaction process is enhanced, the heat exchange efficiency is improved, the temperature of any area of the catalyst bed layer is accurately controlled, and the hot spot generated by heat accumulation is avoided to influence the reaction selectivity and the process safety.

The application of the gap type fixed bed reactor in gas-gas, gas-liquid, gas-solid, liquid-solid, gas-liquid-solid and liquid-liquid mass transfer, such as hydrogenation reduction, oxidation, ozonization, carbonylation and CO ₂ Immobilization and immobilizationThe fields of resource utilization, hydrogen storage-hydrogen release, wastewater treatment and the like.

According to the application method of the gap type fixed bed reactor, the gap type fixed bed reactors are connected in series or in parallel to carry out large-scale amplification; when in series connection, a plurality of gap type fixed bed reactors are directly connected with a material inlet and a material outlet in sequence according to modularized assembly; the material premixing device can be connected according to modularized assembly during parallel connection, and a plurality of cylinders can be connected in parallel to share one set of material premixing device or distributor, so that the complexity of equipment is simplified.

Further, the gap-type fixed bed reactor of the invention comprises a gap channel for filling catalyst, a gap channel inner layer heat exchange channel (for heat exchange fluid in and out), a gap channel outer layer channel (for heat exchange fluid in and out), an inlet and an outlet of reaction materials, and a distributor or a premixer for uniformly entering the gap channel.

Compared with the prior art, the invention has the following advantages and technical effects:

in the multi-gap fixed bed reactor, in order to ensure that reaction materials uniformly enter a gap channel, an inlet pipeline is changed into the same shape as the section of the gap channel in a reducing way, and grid-crossing type mixing channels are arranged in the reducing channel so as to realize that single inlets are distributed into multiple inlets and catalyst filling beds uniformly enter the gap channel. In addition, porous passages or inert porcelain balls can be arranged in the reducing channels to enable the reactant materials to be subjected to multiple cross mixing in the narrow channels to form uniform distribution and then enter the catalyst filling bed layers of the clearance channels.

In the multi-gap fixed bed reactor, in order to ensure good heat exchange efficiency in the reaction process, the inflow and outflow channels of heat exchange fluid are arranged in the inner layer cylinder body forming the gap channel, and the inflow and outflow channels of the heat exchange fluid are arranged outside the outer layer cylinder body, so that double-channel heat exchange is realized, equal-proportion amplification of the heat exchange area is ensured when the filling volume of the gap channel catalyst is amplified, the specific surface area is maintained unchanged, and the amplification effect is avoided.

In the multi-gap fixed bed reactor, in order to realize flexible application of the fixed bed reactor, the fixed bed reactor is divided along the axial direction perpendicular to the reactor, and is separated by a baffle plate or a screen mesh with holes, different catalysts are filled in each section, and the serial operation of multi-step reaction and post-reaction treatment is carried out, so that flexible adjustment of different products or complex products prepared from the same raw material under different catalyst conditions is realized.

In the multi-gap fixed bed reactor, in order to realize easy operability of catalyst filling of the fixed bed reactor, the fixed bed reactor is divided along the axial direction of the reactor, and the divided units are separated by a baffle plate or a screen mesh with holes without influencing the diffusion and mixing of reaction materials in the reactor, so that the separated units can be conveniently extracted and replaced, the catalyst loading and unloading are convenient, and the influence of daily maintenance of the device and the catalyst replacement on the production progress is reduced.

In the multi-gap fixed bed reactor, in order to realize the large-scale amplification of the gap fixed bed reactor, a plurality of gap fixed bed reactors can be connected in series to realize the large-scale amplification in addition to the mode of keeping the specific surface area unchanged by increasing the radial size of the reactor proportionally, and meanwhile, the yield can be flexibly adjusted according to the requirement.

In a word, the gap type fixed bed reactor carries out double-channel heat exchange at the inner side and the outer side of the gap channel, and during amplification, the radial width of the gap channel is accurately regulated and controlled to keep good heat exchange efficiency and mass transfer performance, so that the amplification of the volume order of the gap type fixed bed reactor is realized without influencing the reaction conversion rate and the selectivity. The multi-time cross-type micro-channel mixer or the porous structure mixer is arranged to realize the premixing of a heterogeneous system and the uniformity of material distribution in a catalyst bed layer. The reactor is axially cut to realize the series connection of various reactions by sectionally filling different types of catalysts, so that the production efficiency is improved, and the reactor is axially cut to realize the rapid replacement of the catalyst by sectionally filling the catalysts, so that the operation is simple. The gap type fixed bed reactor is suitable for heterogeneous systems such as gas-solid, liquid-solid, gas-liquid-solid, liquid-liquid and the like, such as hydrogenation reduction, oxidation, ozonization, carbonylation and CO ₂ The reactor has good universal performance in the fields of immobilization and resource utilization, hydrogen storage-hydrogen discharge, wastewater treatment and the like.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:

FIG. 1 is a schematic illustration of catalyst loading, reaction material ingress and egress, and barrel setup for a gap fixed bed reactor;

FIG. 2 is a schematic diagram of the heat exchange fluid arrangement of a gap type fixed bed reactor, wherein 2-a is the upper inlet and lower outlet of the inner layer heat exchange fluid, and the lower inlet and upper outlet of the outer layer heat exchange fluid; 2-b is to arrange a baffle plate to form a U-shaped channel so that the inner layer heat exchange fluid enters and exits from the upper part, and the outer layer heat exchange fluid enters and exits from the lower part;

FIG. 3 is a schematic cross-sectional shape of a gap type fixed bed reactor, wherein 3-a is a fixed bed reactor cylinder which is circular, 3-b is a fixed bed reactor cylinder which is triangular, 3-c is a fixed bed reactor cylinder which is square, and 3-d is a fixed bed reactor cylinder which is gear-shaped;

FIG. 4 is a schematic view of a gap-type fixed bed reactor divided in a direction perpendicular to the axial direction;

FIG. 5 is a schematic view of a gap type fixed bed reactor divided in the axial direction;

FIG. 6 is a schematic view of a gap type fixed bed reactor structure of example 1, 6-a is a schematic view of a longitudinal section of the reactor, and 6-b is a schematic view of a transverse section of the reactor; wherein, 1-material inlet, 2-material outlet, 3-gap channel inner layer heat exchange fluid inlet, 4-gap channel inner layer heat exchange fluid outlet, 5-gap channel outer layer heat exchange fluid inlet, 6-gap channel outer layer heat exchange fluid outlet, 7-perforated screen plate or mesh, 8-catalyst filling layer, 9-inner layer cylinder, 10-middle cylinder, 11-outer layer cylinder, 12-mixer/distributor integration, 13-inner layer cylinder diameter, 14-middle cylinder diameter, 15-outer layer cylinder diameter, 16-gap channel, 17-inner layer heat exchange fluid channel, 18-outer layer heat exchange fluid channel;

FIG. 7 is a schematic view of the structure of a fixed bed reactor of comparative example 1, 7-a is a schematic view of the longitudinal section of the reactor, and 7-b is a schematic view of the transverse section of the reactor; wherein, 1-material inlet, 2-material outlet, 3-outer layer heat exchange fluid inlet, 4-outer layer heat exchange fluid outlet, 5-porous passage mixer, 6-porous passage mixer, 7-catalyst filling layer, 8-inner layer cylinder, 9-outer layer cylinder, 10-inner layer cylinder diameter, 11-outer layer cylinder diameter, 12-heat exchange channel.

Detailed Description

Various exemplary embodiments of the invention will now be described in detail, which should not be considered as limiting the invention, but rather as more detailed descriptions of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the invention described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from consideration of the specification of the present invention. The specification and examples of the present invention are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.

The raw materials, the catalyst, the solvent and the like in the embodiment of the invention are all obtained through purchase.

The catalyst filling and reaction material inlet and outlet schematic diagrams of the gap type fixed bed reactor are shown in figure 1;

schematic of the heat exchange fluid placement of a gap-type fixed bed reactor according to some embodiments of the present invention is shown in FIG. 2;

schematic cross-sectional shape of a gap fixed bed reactor according to some embodiments of the invention is shown in FIG. 3;

schematic of the split vertical to the axial direction of the gap type fixed bed reactor according to some embodiments of the present invention is shown in fig. 4;

schematic of the split axially of the gap fixed bed reactor of some embodiments of the present invention is shown in fig. 5.

In some embodiments of the invention, the mixer and distributor are of the type at least one of a T-microchannel mixer, a Y-microchannel mixer, a multiple cross-microchannel mixer, a porous mixer constructed by sintering or stacking porous structured materials, the width and height of the passages formed by the mixer and the stacking of materials being 50 μm to 5.0cm, preferably 300 μm to 2.0cm. The invention strengthens the mixing efficiency of homogeneous or heterogeneous systems such as gas, gas-liquid, liquid-liquid and the like before entering the catalyst bed by arranging the T-shaped microchannel mixer, the Y-shaped microchannel mixer, the multi-time cross-shaped microchannel mixer, the porous mixer and the like, and utilizes the mixer to uniformly distribute and convey materials to the channels filled with the catalyst bed, thereby avoiding the problem of uneven distribution of the materials in the catalyst bed during large-scale amplification. For example, in some embodiments, the distributor also has the function of a mixer in the actual situation that "the porous screens with porous structures are selected to form porous passages which are distributed in a crossing manner to uniformly mix the reaction solution and the hydrogen gas and then distribute the mixture into the catalyst bed".

Example 1

The structure of the fixed bed reactor of this embodiment is schematically shown in fig. 6, and the reactor is connected by connecting the inner cylinder 9, the middle cylinder 10 and the outer cylinder 11 in concentric circles, and connecting the upper and lower ends by welding or flange. The interval between the inner cylinder 9 and the middle cylinder 10 is a gap channel 16, the lower end of the gap channel 16 is connected with a sieve plate or a screen 7 with holes, 80-mesh quartz sand with the height of 1cm is filled firstly when the catalyst is filled, raney nickel catalyst is filled, and the upper end of the gap channel is covered with 80-mesh quartz sand with the height of 1 cm. The lower end of the gap channel 16 is a material inlet 1, the upper end is a material outlet 2, and the inlet and the outlet are connected by using a conical structure. The middle of the cone is the inlet or outlet. The cone of the inner cylinder 9 and the cone of the middle cylinder 10 are connected to form a clearance channel, a grid cross type mixing passage is arranged in the clearance channel to serve as a mixer of gas-liquid two-phase materials, and meanwhile, the gas-liquid two-phase mixer has the function of a material distributor, so that the gas-liquid two-phase mixer realizes uniform mixing in the grid cross type mixing passage and simultaneously ensures that the material ratio of any position entering the clearance channel 16 is consistent. Two inner layer heat exchange fluid inlets 3 are symmetrically arranged on two sides of the material outlet position in the middle of the cone, penetrate through the clearance channel of the cone and are not communicated with the interior of the cone. The two heat exchange fluid inlets 3 are positioned close to the material outlet 1, so that the influence of too close to the gap channels 16 filled with the catalyst on the uniformity of material distribution caused by the grid-crossing type mixing passage is avoided. Similarly, two inner layer heat exchange fluid outlets 4 are symmetrically arranged on two sides of the position of the material inlet 1 in the middle of the cone, and the connection method is the same as that of the heat exchange fluid inlet 3. The gap between the middle cylinder 10 and the outer cylinder 11 is an outer heat exchange fluid channel 18, a serpentine baffle plate is arranged in the channel to avoid the occurrence of a flow dead zone of heat exchange fluid, and an outer heat exchange fluid inlet and an outer heat exchange fluid outlet are provided with an upper end and a lower end, and an included angle of 180 degrees is formed between the left side and the right side.

Nitroreduction reaction

P-chloronitrobenzene is selected as a substrate, methanol is taken as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, a reactor cylinder is circular (as shown as 3-a in figure 3), the size of the reactor is that the diameter of the inner layer of a gap channel is 10cm (the diameter of the inner layer cylinder), the diameter of the outer layer of the gap channel is 12cm (the diameter of the middle cylinder), the width of the gap channel which can be filled with the catalyst is 1cm, the height is 29cm, the volume is 1L, the catalyst is Raney nickel, and the reaction residence time is 2min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the heat exchange fluid of the inner layer channel is from top to bottom countercurrent, the flow direction of the heat exchange fluid of the outer layer channel is from bottom to top concurrent (as 2-a in figure 2), the reaction liquid and the hydrogen are uniformly mixed by using grid cross type mixing channels and then distributed into a catalyst bed, and the reaction conversion rate is 96% and the selectivity is 98%.

Example 2

Nitroreduction reaction

P-chloronitrobenzene is selected as a substrate, methanol is taken as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, the reactor barrel is circular (as shown as 3-a in figure 3), the size of the reactor is that the diameter of the inner layer of a gap channel is 10cm, the diameter of the outer layer of the gap channel is 12cm, the width of the gap channel filled with a catalyst is 1cm, the height is 29cm, the volume is 1L, the catalyst is Raney nickel, and the reaction residence time is 2min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the inner layer heat exchange fluid is from top to bottom in countercurrent, the flow direction of the outer layer heat exchange fluid is from bottom to top in concurrent flow (as 2-a in figure 2), a porous structure screen mesh is selected to form a cross-distributed porous passage, the reaction liquid and the hydrogen are uniformly mixed and then distributed into a catalyst bed, and the reaction conversion rate is 99% and the selectivity is 98%.

Example 3

Nitroreduction reaction

P-chloronitrobenzene is selected as a substrate, methanol is taken as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, the reactor barrel is circular (as shown as 3-a in figure 3), the size of the reactor is that the diameter of the inner layer of a gap channel is 10cm, the diameter of the outer layer of the gap channel is 12cm, the width of the gap channel filled with a catalyst is 1cm, the height is 29cm, the volume is 1L, the catalyst is Raney nickel, and the reaction residence time is 2min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the inner layer heat exchange fluid is from top to bottom in countercurrent, the flow direction of the outer layer heat exchange fluid is from bottom to top in concurrent flow (as shown as 2-a in figure 2), inert porcelain balls with uniform particle sizes are selected to form porous paths which are distributed in a crossed manner, the reaction liquid and the hydrogen are uniformly mixed and then distributed into a catalyst bed, and the reaction conversion rate is 98% and the selectivity is 99%.

Example 4

Hydrogenation debenzylation reaction

The p-bromophenol protected by benzyl is selected as a substrate, tetrahydrofuran is taken as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 3.5MPa, the reaction temperature is 85 ℃, the reactor barrel is square (as shown as 3-C in figure 3), the size of the reactor is 10cm at the inner side of a gap channel, 12cm at the outer side of the gap channel, 1cm at the width of the gap channel filled with the catalyst, 23cm at the height, 1L at the volume, 10% Pd/C (purchased from the safety Ji Shiji) of the catalyst, and the reaction residence time is 3min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the inner layer heat exchange fluid is from top to bottom, a U-shaped channel (2-b in figure 2) is formed by arranging a baffle plate in the inner layer heat exchange pipeline, the flow direction of the outer layer heat exchange fluid is from bottom to top, a porous passage which is distributed in a crossing way is formed by selecting a screen with a porous structure, the reaction liquid and the hydrogen are uniformly mixed and then distributed into a catalyst bed layer, and the reaction conversion rate is 99% and the selectivity is 98%.

Example 5

Ozone oxidation reaction

P-methoxystyrene is selected as a substrate, ethyl acetate is selected as a solvent, 1.5 equivalent of ozone (mixed gas of ozone and oxygen, ozone concentration is 3.5 mmol/L), reaction pressure is 0.5MPa, reaction temperature is 30 ℃, a reactor cylinder is of an equilateral triangle shape (as shown in 3-b) in fig. 3, the size of the reactor is that the inner side length of a gap channel is 10cm, the outer side length of the gap channel is 12cm, the width of the gap channel is 0.86cm, the height is 52.5cm, the volume is 1L, inert porcelain balls with the particle size of 500 mu m are filled in the gap channel, and reaction residence time is 1min. The flow direction of the reaction liquid and the ozone-oxygen mixed gas is from bottom to top, the flow direction of the inner layer heat exchange fluid is from top to bottom, a U-shaped channel is formed by arranging a baffle plate in an inner layer heat exchange pipeline, the flow direction of the outer layer heat exchange fluid is from bottom to top downstream (as 2-b in figure 2), the reaction liquid and the ozone-oxygen mixed gas are uniformly mixed by using a grid cross type mixing passage and then distributed into an inert porcelain ball filling layer, the reaction conversion rate is 98%, and the selectivity of the product p-methoxybenzaldehyde is 94%.

Example 6 (size enlargement)

Nitroreduction reaction

P-chloronitrobenzene is selected as a substrate, methanol is taken as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, the reactor barrel is circular (as shown as 3-a in figure 3), the size of the reactor is that the diameter of the inner layer of a gap channel is 58cm, the diameter of the outer layer of the gap channel is 60cm, the width of the gap channel filled with a catalyst is 1cm, the height is 539cm, the volume is 100L, the catalyst is Raney nickel, and the reaction residence time is 2min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the inner layer heat exchange fluid is from top to bottom in countercurrent, the flow direction of the outer layer heat exchange fluid is from bottom to top in concurrent flow (as 2-a in figure 2), a porous structure screen mesh is selected to form a cross-distributed porous passage, the reaction liquid and the hydrogen are uniformly mixed and then distributed into a catalyst bed, and the reaction conversion rate is 99% and the selectivity is 98%.

Example 7 (series connection)

Nitroreduction reaction

P-chloronitrobenzene is selected as a substrate, methanol is used as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, the reactor cylinder is round (as shown as 3-a in figure 3), the reactors are three groups of reactors connected in series, the size is 58cm for the inner layer diameter of a gap channel, 60cm for the outer layer diameter of the gap channel, 1cm for the gap channel for filling the catalyst, and 135cm for the height. The heights of the three groups of back clearance channels connected in series are accumulated to be 540cm, the volumes of the back clearance channels are accumulated to be 100L, the catalyst is Raney nickel, and the reaction residence time is 2min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the inner layer heat exchange fluid is from top to bottom in countercurrent, the flow direction of the outer layer heat exchange fluid is from bottom to top in concurrent flow (as 2-a in figure 2), a porous structure screen mesh is selected to form a cross-distributed porous passage, the reaction liquid and the hydrogen are uniformly mixed and then distributed into a catalyst bed, and the reaction conversion rate is 99% and the selectivity is 99%.

Example 8 (division in the axial direction perpendicular to the reactor)

Aromatic aldimine-imine reduction tandem reaction

Benzaldehyde is selected as a substrate, phenethylamine is used as a reagent, the dosage is 1.1 equivalent, toluene is used as a solvent, the dosage of hydrogen is 1.5 equivalent, the reaction pressure is 2.0MPa, the reaction temperature is 40 ℃, the reactor barrel is circular (as shown as 3-a in figure 3), the size of the reactor is 10cm in diameter of the inner layer of a gap channel, 12cm in diameter of the outer layer of the gap channel, 1cm in width of the gap channel filled with the catalyst, 29cm in height (the total height of the upper end and the lower end), and 1L in volume. The gap channel is divided into an upper section and a lower section along the axial direction perpendicular to the reactor, the lower section is filled with alkaline resin to catalyze imidization reaction of aromatic aldehyde and phenethylamine, and the upper section is filled with 5% Pd/C catalyst (purchased from security Ji Shiji) to catalyze reduction of imine double bond. The upper and lower layers are separated by a sieve plate with 15-30 μm holes to prevent the two catalysts from being mixed by diffusion. The total residence time of the reaction was 3min. The reaction liquid of benzaldehyde and phenethylamine and the hydrogen flow from bottom to top, the flow direction of the inner layer heat exchange fluid is countercurrent from top to bottom, the flow direction of the outer layer heat exchange fluid is downstream from bottom to top, and the reaction liquid and the hydrogen are uniformly mixed by using grid-crossing type mixing passages and then distributed into a catalyst bed layer, wherein the reaction conversion rate is 97%, and the selectivity is 98%.

Example 9 (axial separation along the reactor)

Nitroreduction reaction

P-chloronitrobenzene is selected as a substrate, methanol is taken as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, the reactor barrel is circular (as shown as 3-a in figure 3), the size of the reactor is that the diameter of the inner layer of a gap channel is 10cm, the diameter of the outer layer of the gap channel is 12cm, the width of the gap channel filled with a catalyst is 1cm, the height is 29cm, the volume is 1L, the catalyst is Raney nickel, and the reaction residence time is 2min. The gap channel is divided into six sections equally along the axial direction of the reactor, each section is separated on two sides by a sieve plate with 15-30 mu m holes, and the diffusion and mixing of the catalyst between the adjacent two ends are prevented. The bottom of each section is separated by a sieve plate with 15-30 mu m holes, so that each section can be quickly extracted from a gap channel to replace the catalyst (each section is filled with the same catalyst, the effect is that the two sides and the bottom are separated by the sieve plates and are equivalent to independent blocks, and the catalyst can be directly extracted from the upper part to conveniently discharge and replace. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the inner layer heat exchange fluid is from top to bottom countercurrent, the flow direction of the outer layer heat exchange fluid is from bottom to top downstream, and grid-crossing type mixing passages are selected to uniformly mix the reaction liquid and the hydrogen and then distribute the mixture into a catalyst bed layer, so that the reaction conversion rate is 98% and the selectivity is 99%.

Comparative example 1

The structure of the fixed bed reactor of this example is schematically shown in FIG. 7.

P-chloronitrobenzene is selected as a substrate, methanol is taken as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, the inner diameter of a circular channel of a reactor is 2cm, the height is 318cm, the volume is 1L, the catalyst is Raney nickel, and the reaction residence time is 2min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the outer layer heat exchange fluid is from top to bottom in countercurrent, a porous passage which is distributed in a crossing way is formed by selecting a porous screen, the reaction liquid and the hydrogen are uniformly mixed and then enter a catalyst bed, and the reaction conversion rate is 88% and the selectivity is 90%.

Comparative example 2

P-chloronitrobenzene is selected as a substrate, methanol is used as a solvent, the hydrogen consumption is 3 equivalents, the reaction pressure is 2.5MPa, the reaction temperature is 70 ℃, the inner diameter of a circular channel (shown as a in figure 3 a) of a reactor is 20cm, the height is 318cm, the volume is 100L, the catalyst is Raney nickel, and the reaction residence time is 2min. The flow direction of the reaction liquid and the hydrogen is from bottom to top, the flow direction of the outer layer heat exchange fluid is from top to bottom in countercurrent, a porous passage which is distributed in a crossing way is formed by selecting a porous screen, the reaction liquid and the hydrogen are uniformly mixed and then enter a catalyst bed, and the reaction conversion rate is 72% and the selectivity is 81%.

Comparative examples 1 and 2 each had no intermediate cylinder, only two cylinders, with the innermost catalyst and the outer heat exchange fluid. It can be seen from examples 1 and 6 that the reaction can maintain consistent conversion and selectivity when the reactor volume is enlarged from 1L by 100 times to 100L, indicating that the gap-type fixed bed reactor has good scale-up application capability and avoids the scale-up effect. It can be seen from examples 1 and 7 that the reaction can maintain consistent conversion rate and selectivity when the reactor volume is enlarged from 1L to 100L by three groups of series connection modes, which indicates that the gap type fixed bed reactor has good scale-up application capability, avoids the scale-up effect and has flexible and changeable scale-up modes. Meanwhile, the height of each group of reactors can be reduced when the reactors are amplified in series, the reactors are easier to process and detect and maintain in the production process, and the practicability is higher. It can be seen from example 4 that the gap-type fixed bed reactor is also applicable to filling and catalytic reaction of other solid catalysts, and has good universality. As can be seen from example 5, the gap-type fixed bed reactor can be used for heterogeneous reactions such as gas-liquid two-phase or liquid-liquid immiscible two-phase by filling inert carrier to strengthen the mass transfer process of the gas-liquid two-phase or liquid-liquid immiscible two-phase besides filling catalyst.

As can be seen from comparative examples 1 and 2, the fixed bed reactor obtained by simple channel size enlargement has significantly reduced reaction conversion, and the product selectivity is drastically reduced due to the reduced specific surface area after size enlargement, and the heat exchange capacity of the reactor is greatly reduced, resulting in an increase in byproducts. Further illustrates that the gap type fixed bed reactor developed by design has wide application prospect, especially in large-scale production.

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. The gap type fixed bed reactor is characterized by comprising an inner layer cylinder body, a middle cylinder body and an outer layer cylinder body, wherein the inner layer cylinder body, the middle cylinder body and the outer layer cylinder body are consistent in shape; the inner layer cylinder, the middle cylinder and the outer layer cylinder are sequentially arranged from inside to outside; a clearance channel exists between the inner layer cylinder and the middle cylinder;

the interstitial channels are used to fill solid catalysts or inert supports.

2. The gapped fixed bed reactor of claim 1 wherein the gapped channels are provided with inlets and outlets for materials.

3. The gap-type fixed bed reactor according to claim 1, wherein the gap-type fixed bed reactor is divided into several sections in an axial direction perpendicular to the reactor, the height is equal or unequal, and adjacent sections are separated by a perforated partition or screen with a smaller pore diameter than the particle size of the catalyst or inert carrier.

4. The gapped fixed bed reactor of claim 1 wherein the radial width of the gapped channels is from 0.1 to 10cm.

5. The gap-type fixed bed reactor according to claim 4, wherein the radial width of the gap channel is changed to 50% -20000% of the original width and the axial height is changed to 50% -20000% of the original width during large-scale amplification.

6. The gap-type fixed bed reactor according to claim 5, wherein the radial width of the gap channel is changed to 50% -1000% of the original width and the axial height is changed to 80% -15000% of the original width during the large-scale amplification.

7. The gap-type fixed bed reactor according to claim 1, wherein a plurality of units are divided in an axial direction of the fixed bed reactor.

8. The gap-type fixed bed reactor according to claim 1, wherein heat exchange is performed at both sides of the gap channel, and the direction of the heat exchange fluid at the inner side of the gap channel is the same as or opposite to the material flow direction; or a baffle plate is arranged in the heat exchange pipeline at the inner side of the clearance channel to form a U-shaped channel so that heat exchange fluid enters and exits upwards or enters and exits downwards, and the direction of the heat exchange fluid at the outer side of the clearance channel is the same as or opposite to the material flowing direction.

9. Use of the gapped fixed bed reactor of any one of claims 1 to 8 in gas-gas, gas-liquid, gas-solid, liquid-solid, gas-liquid-solid and liquid-liquid mass transfer.

10. A method of using the gapped fixed bed reactor of any one of claims 1 to 8, wherein the plurality of gapped fixed bed reactors are scaled up in series or in parallel;

when in series connection, a plurality of gap type fixed bed reactors are directly connected with a material inlet and a material outlet in sequence according to modularized assembly;

when in parallel connection, the material premixing devices are connected according to modularized assembly, or a plurality of cylinders are connected in parallel to share one set of material premixing devices or distributing devices.