A fixed-fluidized bed reactor for use in a multiphase catalytic reaction
By designing a fixed-fluidized bed reactor and utilizing hollow carrier materials and external field control methods, the problems of low mass and heat transfer efficiency and catalyst loss in fixed-bed and fluidized-bed reactors were solved, thus achieving a highly efficient heterogeneous catalytic reaction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- QUZHOU INSTITUTE FOR INNOVATION IN RESOURCE CHEMICAL ENGINEERING
- Filing Date
- 2023-08-30
- Publication Date
- 2026-05-26
AI Technical Summary
Existing fixed-bed and fluidized-bed reactors suffer from problems such as catalyst loss, low mass and heat transfer efficiency, and difficulty in stabilizing temperature and pressure gradients under high temperature and high pressure conditions, failing to effectively combine the advantages of both.
A fixed-fluidized bed reactor is designed, in which a catalyst is encapsulated in a hollow carrier material and fluidized under the action of gas and liquid phases. Combined with external field assistance such as temperature control, magnetic field control or microwave control, the disturbance of the catalyst and the reaction efficiency are enhanced.
This improved catalyst utilization efficiency, reduced catalyst loss, enhanced heat transfer efficiency, and achieved stability of reaction conditions and improved catalytic efficiency.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of reactor design, specifically to a fixed-fluidized bed reactor for multiphase catalytic reactions. Background Technology
[0002] Fixed-bed and fluidized-bed reactors can meet the high-temperature and high-pressure requirements of most catalytic reactions, making them widely used in industrial production processes. A fixed-bed reactor consists of a feed layer, a catalyst-packed bed, and a discharge layer. Reactants enter the catalyst-packed bed through the feed layer, contacting the catalyst to achieve a multiphase reaction. High conversion rates can be achieved by controlling the residence time of reactants, and the catalyst is less prone to wear after prolonged reactions. However, during the reaction, the catalyst supported on the carrier can detach due to collisions, resulting in significant catalyst loss, low catalyst utilization efficiency, poor mass and heat transfer, and difficulty in maintaining stable reaction conditions due to temperature and pressure gradients at different heights. A fluidized-bed reactor uses gas or liquid to suspend catalyst particles, effectively improving mass and heat transfer rates. Compared to a fixed bed, a fluidized bed offers uniform temperature, a large contact area between the catalyst and reactants, and high catalytic efficiency. However, collisions between catalyst particles during the reaction make them prone to breakage and loss with the waste liquid, resulting in significant catalyst loss. To further improve the efficiency of fixed-bed and fluidized-bed reactors, researchers both domestically and internationally have conducted systematic studies on the common problems existing in fixed-bed and fluidized-bed reactors. The literature Chem. Eng. J., 2021, 423, 130244 optimizes the structure of a traditional vertical fixed-bed reactor, designing a concentric inner tube rotating fixed-bed reactor for the hydrogenation reaction of α-methylstyrene. During the reaction, the reactor is tilted at 45°, with a reaction rate of 1 rpm·s. -1 The rotational speed of the rotary reactor effectively improves mass and heat transfer efficiency, enhances stability under different temperature and pressure gradients, and improves the hydrogenation performance of α-methylstyrene by about 20%. The literature Adv. Powder. Technol., 2021, 32, 10, 3499-3505 optimizes the traditional fluidized bed reactor by adding a vortex structure inside the reactor and injecting particles into the reactor at a rate of 1 kg / s. By comparing the particle loss rate at different injection points, it was found that particle loss is minimal when injected through the rear wall, effectively mitigating the problem of catalyst particle collision and loss in the fluidized bed.
[0003] Currently, thanks to extensive research by scholars both at home and abroad, encouraging progress has been made in the structural optimization of fixed-bed and fluidized-bed reactors. However, the limitations inherent in the reactor structure itself have not been adequately addressed. Therefore, a novel fixed-fluidized-bed concept is proposed. By designing the bed structure and combining the advantages of both fixed-bed and fluidized-bed reactors, a novel fixed-fluidized-bed reaction device for multiphase catalytic processes is invented. Summary of the Invention
[0004] The present invention aims to develop a fixed-fluidized bed reactor, the technical solution of which is as follows:
[0005] An invention discloses a fixed-fluidized bed reactor, wherein "fixed" refers to fixing a hollow carrier material within the reactor, and "fluidized" refers to the process where, after gaseous and liquid feedstocks are introduced into the hollow porous material cavity, the catalyst encapsulated within the cavity is subjected to the buoyancy of the gas and liquid phases, resulting in a regional fluidized state within the cavity. The fixed-fluidized bed reactor comprises, from bottom to top, a feedstock inlet, a catalyst filling inlet, and a reaction outlet inlet, with a circulation section and an auxiliary control section at the side.
[0006] The raw material feeding section consists of a raw material inlet tube 1, a jet tube 2, and a connecting tube 3. The inner diameter of the inlet tube 1 is 4-8 mm, the thickness is 1-4 mm, and the height is 30-70 mm. Its lower end is connected to the raw material conveying system and can convey gas phase, liquid phase, or gas-liquid mixture. The upper end of the inlet tube has an upwardly extending jet tube 2, whose inner diameter gradually and linearly decreases to 0.4-0.8 times the inner diameter of the inlet tube, and its height is 35-120 mm. The outer layer of the jet tube is the connecting tube 3, whose upper end is connected to the catalyst packing layer. The inner diameter of the connecting tube is 1.5-3 times the inner diameter of the inlet tube, the wall thickness is 1-4 mm, and the height is 1.5-2 times the height of the inlet tube.
[0007] The upper layer of the raw material feeding section is the catalyst filling section, which consists of porous grid plates 4, catalyst filling tubes 5, and hollow porous material 6. The catalyst filling tube 5 has an inner diameter of 15-30 mm, a wall thickness of 1-4 mm, and a height of 70-700 mm. Inside the tube, 4-6 sets of grid plates 4 and hollow porous material 6 are stacked, with a stacking height 2-6 times the inner diameter. The bottom is a porous cylindrical grid plate 4 with a diameter the same as the inner diameter of the filling tube and a thickness of 3-6 mm. The grid plate has evenly distributed grooves, which are hemispherical or conical in shape, with a diameter of 3-6 mm. The centers of each groove on the top cross-section of the grid plate are spaced 3-27 mm apart, and there are 4-16 grooves in total. The bottom of the concave surface has connecting holes with a diameter of 0.1-1.5 mm. Hollow porous material is stacked on the grid plate. Hollow porous material refers to a millimeter-sized catalyst carrier with a cavity structure and mesopores or micropores, with a particle size of 2-5 mm and an internal cavity diameter of... The material, ranging from 0.5 to 2 mm in diameter, comprises alumina, silica, and carbon materials with hollow spheres or hollow tube structures. Nanoscale or microscale catalysts are filled within the cavities of the hollow porous material. Four to six sets of grid plates and hollow porous material are stacked inside the tube. Each grid plate contains 10-30 mm of hollow porous material. The diameter of the connecting holes at the bottom of the concave surface of the stacked grid plates decreases by 0.1-0.35 mm from bottom to top. The diameter of the connecting holes at the bottom of the concave surface of the bottom grid plate is 0.4-1.5 mm, and the diameter of the connecting holes on the topmost grid plate is 0.1-1.2 mm. Reducing the diameter of the connecting holes reduces the molecular diameter of the gas, liquid, or gas-liquid mixtures passing through, making it easier for the raw material to enter the cavity through the pores of the hollow porous material. A filling height to inner diameter ratio of 2-6 ensures efficient catalyst utilization.
[0008] The upper part of the catalyst filling section is the reaction discharge section, which is the discharge pipe 9, connected to an external separation and collection system. The inner diameter of the discharge pipe is 19-24mm, the thickness is 1-5mm, and the height is 30-70mm.
[0009] The side end has a circulation section and an auxiliary control section. The circulation section is a reflux tube 8 with an inner diameter of 5-10 mm and a thickness of 1-5 mm. The lower end of the tube is located inside the connecting tube of the raw material injection section, 50-120 mm higher than the raw material injection tube. The upper end of the tube is 60-210 mm higher than the bottom of the packing layer. The horizontal length of the reflux tube is 15-40 mm and the height is 70-300 mm.
[0010] The outer layer of the reactor is an external field control system 7, which controls temperature, magnetic field, or microwave. Temperature control provides the necessary thermal field for the reactor. The external magnetic field enhances the disturbance of the catalyst by controlling the magnetic microspheres inside the hollow carrier. The magnetic microspheres are magnetic composite microspheres formed by combining magnetic inorganic particles with organic polymers. The magnetic inorganic particles include oxides of Fe, Co, and Ni, and the organic polymer materials include cellulose, polystyrene, or polyamide materials. The particle size of the composite microspheres is 50-1*10. 4 The sample has a mass of 0.5-3 mg and a charge of 10-50 C. The magnetic field is generated by a solenoid connected to a power source. The solenoid is composed of insulated wire tightly wound around a cylindrical iron ring. The number of turns of the coil wound in the solenoid is more than 60. The voltage is 220V and the current is 0-10A. The microwave part is connected to an external microwave generator to induce vibrations in the gas or liquid phase to enhance the disturbance of the catalyst inside the hollow carrier. Microwave energy can be generated by a magnetron, traveling wave tube, or microwave oscillator. An external power supply and transformer are connected. The power supply voltage is 220V and the current is 0-10A. The transformer reduces the voltage to between 50-150V to reach the rated voltage of the microwave generator to protect the instrument. The microwave frequency generated by the microwave generator is 1-5MHz.
[0011] The reactor is filled with 10-170 ml of feed solution. When the volume of the feed solution increases or decreases beyond 10-170 ml, the height and inner diameter should be increased or decreased by 0.5-1.5 times the amount of the original solution increase or decrease.
[0012] The beneficial effects achieved by this invention are as follows: This invention combines the advantages of fixed-bed and fluidized-bed reactors, resulting in low catalyst particle loss and high heat transfer efficiency. The raw material gaseous, liquid, or gas-liquid mixture enters the catalyst-filling section through the reactor's raw material inlet. After contacting the hollow porous material through the connecting holes on the grid plate, it enters the cavity through the channels on the material surface. The catalyst powder filled inside is fluidized within the cavity under the disturbance of the gaseous, liquid, or gas-liquid mixture. An external magnetic field or microwave can further promote the fluidization of the catalyst powder, increasing the collision probability between the reactants and the catalyst powder, thereby... To improve catalytic efficiency, the catalyst is encapsulated in a cavity to reduce loss, and the hollow support is fixed in the tray to reduce wear. The mixed phase after reaction is released through the pores of the material, and the reaction liquid can be refluxed through the reflux pipe at the side of the reactor to achieve complete reaction. The external field control section can be composed of one or more of temperature control, magnetic field control, or microwave control. Temperature control provides the necessary thermal field for the reactor, the external magnetic field enhances the disturbance of the catalyst by controlling the magnetic microspheres inside the hollow support, and the microwave section uses an external microwave generator to cause vibration of the gas or liquid phase to enhance the disturbance of the catalyst inside the hollow support. Attached Figure Description
[0013] Figure 1 Here are schematic diagrams of the fixed-fluidized bed reactor of the present invention: (a) front view of the fixed-fluidized bed reactor, (b) side view of the fixed-fluidized bed reactor, and (c) top view of the fixed-fluidized bed reactor.
[0014] Figure 2 Here are schematic diagrams of grating plates: (a) Schematic diagram of conical perforated grating plate, (b) Schematic diagram of hemispherical perforated grating plate;
[0015] Figure 3 It serves as a millimeter-scale hollow support for encapsulating catalysts;
[0016] Figure 4 For Application Example 1, a comparison of hydrogenation efficiency between hollow spherical supports and solid spherical supports with the same catalyst loading is presented.
[0017] In the figure, 1. Feed pipe; 2. Jet pipe; 3. Connecting pipe; 4. Porous grid plate; 5. Catalyst filling pipe; 6. Millimeter-scale hollow porous carrier for encapsulating catalyst; 7. External control system; 8. Return pipe; 9. Discharge pipe; 10. Conical grid plate; 11. Hemispherical grid plate; 12. Hollow spherical shell; 13. Catalyst powder; 14. Channel. Detailed Implementation
[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but this is not intended to limit the present invention.
[0019] Example 1
[0020] The feed layer of the fixed-fluidized bed reactor is designed with an inner diameter of 6 mm, a thickness of 1 mm, and a height of 30 mm for the inlet tube, and the jet tube gradually shrinks to 4 mm with a height of 50 mm; the connecting tube has an inner diameter of 15 mm, a wall thickness of 1.5 mm, and a height of 60 mm.
[0021] The catalyst packing layer has an inner diameter of 20 mm, a thickness of 1.5 mm, and a height of 380 mm. It is filled with 5 sets of grid plates and hollow spherical alumina carriers for millimeter-level encapsulation of catalyst. The grid plates are 3 mm thick and have a hemispherical groove structure with a total of 7 grooves. The concave diameter is 4 mm. Hollow alumina spheres with a diameter of 3 mm are stacked on top. The filling height of each layer is 16 mm. The diameter of the connecting hole in the groove of the bottom grid plate is 1.5 mm. The diameter decreases by 0.2 mm from bottom to top. The diameter of the connecting hole in the groove of the fifth grid plate is 0.8 mm. The total filling height of the 5 sets is 100 mm.
[0022] The discharge pipe has an inner diameter of 24mm, a thickness of 1.5mm, and a height of 30mm.
[0023] The inner diameter of the side return pipe is 6mm, the thickness is 1.5mm, the bottom pipe opening is 50mm higher than the feed pipe, the top pipe opening is 120mm higher than the bottom of the filler layer, the length is 30mm, and the height is 130mm.
[0024] Before operation, weigh 8g of hollow spherical alumina support with a particle size of 3mm and an internal cavity diameter of 1.3mm. Fill the cavity with 1mg of Pd / Al2O3 with a particle size of 700nm. Uniformly fill the hollow spherical alumina support and supporting material into the fixed-fluidized bed reactor. The outer layer of the reactor is a temperature control system, and the temperature of the temperature control system is set to 50℃. Mix the feed liquid and the reaction gas and then transport it into the fixed-fluidized bed reactor through the feed pipe. The gas-liquid mixture enters the inner cavity through the channels of the hollow spherical alumina support. The catalyst powder inside is in a fluidized state under the flow of gas and liquid. After the gas-liquid mixture comes into contact with the catalyst, the reaction is accelerated. The reacted gas-liquid mixture diffuses out through the channels and is then transported to a gas collection bottle through the upper outlet for storage. After the reaction, collect the reaction liquid in the feed liquid collection tank for storage. After the liquid is drained, disassemble the device and clean the feed storage tank and the fixed-fluidized bed reactor for storage.
[0025] Example 2
[0026] The feed layer of the fixed-fluidized bed reactor is designed with an inner diameter of 7 mm, a thickness of 1.5 mm, and a height of 40 mm for the inlet tube, and the jet tube gradually shrinks to 4 mm with a height of 50 mm; the connecting tube has an inner diameter of 16 mm, a wall thickness of 1.5 mm, and a height of 70 mm.
[0027] The catalyst packing layer has an inner diameter of 22 mm, a thickness of 1.5 mm, and a height of 450 mm. It is filled with 6 sets of grid plates and hollow spherical alumina carriers for millimeter-level encapsulated catalyst. The grid plates are 4 mm thick, and the grooves on the grid plates are hemispherical structures with a total of 7 concave surfaces. The diameter of the concave surfaces is 4 mm. Hollow alumina spheres with a diameter of 3.3 mm are stacked on top. The filling height of each layer is 15 mm. The diameter of the connecting hole in the groove of the bottom grid plate is 1.4 mm. The diameter decreases by 0.15 mm from bottom to top, and the diameter of the connecting hole in the groove of the sixth grid plate is 0.65 mm. The total filling height of the 6 sets is 120 mm.
[0028] The discharge pipe has an inner diameter of 24mm, a thickness of 1.5mm, and a height of 50mm.
[0029] The inner diameter of the side return pipe is 8mm, the thickness is 1.5mm, the bottom pipe opening is 55mm higher than the feed pipe, the top pipe opening is 150mm higher than the bottom of the filler layer, the length is 30mm, and the height is 165mm.
[0030] Before operation, 10g of hollow spherical alumina support was weighed. The alumina support had a particle size of 3.3mm and an internal cavity diameter of 1.5mm. The cavity was filled with 1mg of Pd / Al₂O₃ (500nm particle size) and 2mg of CoFe₂O₄ (10μm particle size) bonded to polystyrene, with a charge of 10C. The hollow spherical alumina support and supporting material were uniformly filled into a fixed-fluidized bed reactor. The outer layer of the reactor was a magnetic field control system, consisting of surface-insulated wires tightly wound around a cylindrical iron ring. The wire current intensity was 1.9A, the coil had 100 turns, and the winding height was 140mm. The generated magnetic field had a magnetic induction intensity of B = 2.4 * 10⁻⁶. -4 T; The raw material liquid and the reaction gas are mixed and then transported to the fixed-fluidized bed reactor through the feed pipe. The gas-liquid mixture enters the inner cavity through the pores of the hollow spherical alumina carrier. The catalyst powder inside is in a fluidized state under the flow of gas and liquid. With the assistance of the magnetic field control system, the magnetic microspheres enhance the disturbance of the catalyst. The gas-liquid mixture after the reaction diffuses out through the pores. After the reaction, it is transported to the gas collection bottle through the upper outlet and stored. After the reaction is completed, the reaction liquid is collected in the feed liquid collection tank and stored. After the liquid is drained, the device is disassembled, and the raw material storage tank and the fixed-fluidized bed reactor are cleaned and stored.
[0031] Example 3
[0032] The feed layer of the fixed-fluidized bed reactor is designed with an inner diameter of 4 mm, a thickness of 2 mm, and a height of 50 mm for the inlet tube, and the jet tube gradually shrinks to 2.4 mm with a height of 40 mm; the connecting tube has an inner diameter of 7 mm, a wall thickness of 2 mm, and a height of 80 mm.
[0033] The catalyst packing layer has an inner diameter of 18 mm, a thickness of 2 mm, and a height of 300 mm. It is filled with 6 sets of grid plates and hollow spherical silica carriers for millimeter-level encapsulation of catalyst. The grid plates are 3.5 mm thick and have conical grooves with 7 concave surfaces and a diameter of 4 mm. Hollow silica spheres with a diameter of 3 mm are stacked on top. Each layer is 13 mm high. The diameter of the connecting hole in the groove of the bottom grid plate is 1.4 mm. The diameter decreases by 0.1 mm from bottom to top, reaching 0.9 mm in the diameter of the connecting hole in the groove of the sixth grid plate. The total height of the 6 sets is 120 mm.
[0034] The discharge pipe has an inner diameter of 24mm, a thickness of 2mm, and a height of 50mm;
[0035] The inner diameter of the side return pipe is 5mm, the thickness is 2mm, the bottom pipe opening is 60mm higher than the feed pipe, the top pipe opening is 150mm higher than the bottom of the filler layer, the length is 20mm, and the height is 170mm.
[0036] Before operation, 14g of hollow spherical silica support was weighed out. The support was filled with 0.5mg of 1μm Pt / Al₂O₃ particles and 1mg of 5μm Fe₃O₄ particles bonded to polystyrene, with a charge of 16C. The hollow spherical silica support and supporting material were uniformly filled into a fixed-fluidized bed reactor. The outer layer of the reactor was a magnetic field control system, consisting of surface-insulated wires tightly wound around a cylindrical iron ring. The wire current intensity was 1.5A, the coil had 80 turns, and the winding height was 100mm. The generated magnetic field had a magnetic induction intensity of B = 1.5 * 10⁻⁶. -4 T; The raw material liquid and the reaction gas are mixed and then transported to the fixed-fluidized bed reactor through the feed pipe. The gas-liquid mixture enters the inner cavity through the pores of the hollow spherical silica carrier. The catalyst powder inside is in a fluidized state under the flow of gas and liquid. With the assistance of the magnetic field control system, the magnetic microspheres enhance the disturbance of the catalyst. The gas-liquid mixture after the reaction diffuses out through the pores. After the reaction, it is transported to the gas collection bottle through the upper outlet and stored. After the reaction is completed, the reaction liquid is collected in the feed liquid collection tank and stored. After the liquid is drained, the device is disassembled, and the raw material storage tank and the fixed-fluidized bed reactor are cleaned and stored.
[0037] Example 4
[0038] The feed layer of the fixed-fluidized bed reactor is designed with an inner diameter of 8 mm, a thickness of 2 mm, and a height of 40 mm. The jet tube gradually shrinks to 5 mm and has a height of 70 mm. The connecting tube has an inner diameter of 16 mm, a wall thickness of 2 mm, and a height of 80 mm.
[0039] The catalyst packing layer has an inner diameter of 22 mm, a thickness of 2 mm, and a height of 480 mm. It is filled with 5 sets of grid plates and hollow spherical carbon supports for millimeter-level encapsulation of the catalyst. The grid plates are 4 mm thick, and the grooves on the grid plates are hemispherical structures with a total of 8 concave surfaces. The diameter of the concave surfaces is 5 mm. Hollow carbon spheres with a diameter of 5 mm and a height of 4 mm are stacked on top. The filling height of each layer is 21 mm. The diameter of the connecting hole in the groove of the bottom grid plate is 1.1 mm. The diameter decreases by 0.1 mm from bottom to top. The diameter of the connecting hole in the groove of the fifth grid plate is 0.7 mm. The total filling height of the 5 sets is 130 mm.
[0040] The discharge pipe has an inner diameter of 24mm, a thickness of 1.5mm, and a height of 30mm.
[0041] The inner diameter of the side return pipe is 8mm, the thickness is 1mm, the bottom pipe opening is 65mm higher than the feed pipe, the top pipe opening is 180mm higher than the bottom of the filler layer, the length is 40mm, and the height is 195mm.
[0042] Before operation, 16g of hollow spherical carbon support was weighed and filled with 1mg of Pd / Al2O3 with a particle size of 900nm. The hollow spherical carbon support and supporting material were uniformly filled into a fixed-fluidized bed reactor. The outer layer of the reactor was a microwave control system, consisting of a transformer and a microwave oscillator. The external voltage was 220V, which was reduced to 80V by the transformer, with a current of 0.5A. The electromagnetic frequency of the microwave oscillator was 1MHz. The feed liquid and reaction gas were mixed and fed into the fixed-fluidized bed reactor through the feed pipe. The gas-liquid mixture entered the inner cavity through the pores of the hollow spherical carbon support. The catalyst powder inside was in a fluidized state under the flow of gas and liquid. With the assistance of the microwave control system, the gas-liquid phase oscillation was enhanced, further strengthening the fluidization of the catalyst. After the reaction, the mixture was fed into a gas collection bottle through the upper outlet and stored. After the reaction was completed, the reaction liquid was collected in a liquid collection tank and stored. After the liquid was drained, the device was disassembled, and the feed storage tank and the fixed-fluidized bed reactor were cleaned and stored.
[0043] Example 5
[0044] The feed layer of the fixed-fluidized bed reactor is designed with an inner diameter of 8 mm, a thickness of 4 mm, and a height of 70 mm. The jet tube gradually shrinks to 6 mm and has a height of 120 mm. The connecting tube has an inner diameter of 16 mm, a wall thickness of 4 mm, and a height of 140 mm.
[0045] The catalyst packing layer has an inner diameter of 30 mm, a thickness of 4 mm, and a height of 700 mm. It is filled with 5 sets of grid plates and hollow tubular alumina carriers for millimeter-level encapsulated catalyst. The grid plates are 6 mm thick and have conical grooves with 12 concave surfaces, each with a diameter of 6 mm. Hollow alumina tubes with a diameter of 4 mm and a height of 6 mm are stacked on top. Each layer is 24 mm high. The diameter of the connecting hole in the groove of the bottom grid plate is 1.4 mm, decreasing by 0.2 mm from bottom to top, until the diameter of the connecting hole in the groove of the fifth grid plate is 0.6 mm. The total height of the 5 sets is 150 mm.
[0046] The discharge pipe has an inner diameter of 24mm, a thickness of 4mm, and a height of 70mm.
[0047] The inner diameter of the side return pipe is 10mm, the thickness is 5mm, the bottom pipe opening is 100mm higher than the feed pipe, the top pipe opening is 180mm higher than the bottom of the filler layer, the length is 40mm, and the height is 220mm.
[0048] Before operation, 18g of a hollow tubular alumina support, 4mm in diameter, 6mm in height, and 2mm in wall thickness, was weighed and filled with 2mg of Pt / Al₂O₃ with a particle size of 900nm. The hollow tubular alumina support and supporting material were uniformly filled into a fixed-fluidized bed reactor. The outer layer of the reactor was a microwave control system, consisting of a transformer, a magnetron, and a metal shell. The external voltage was 220V, which was stepped down to 100V by the transformer, with a current of 0.2A. The electromagnetic frequency of the magnetron was 5MHz. The feed liquid and the reaction gas were mixed and then transported through the feed pipe. In the fixed-fluidized bed reactor, the gas-liquid mixture enters the inner cavity through the hollow tubular alumina carrier channels. The catalyst powder inside is in a fluidized state under the flow of gas and liquid. With the assistance of the microwave control system, the gas-liquid phase oscillates more strongly, further enhancing the fluidization of the catalyst. The gas-liquid mixture after the reaction diffuses out through the channels and is then conveyed to a gas collection bottle through the upper outlet for storage. After the reaction is completed, the reaction liquid is collected in a feed liquid collection tank for storage. After the liquid is drained, the device is disassembled, and the raw material storage tank and the fixed-fluidized bed reactor are cleaned and stored.
[0049] Example 6
[0050] The feed layer of the fixed-fluidized bed reactor is designed with an inner diameter of 7 mm, a thickness of 2 mm, and a height of 40 mm. The jet tube gradually shrinks to 5 mm and has a height of 60 mm. The connecting tube has an inner diameter of 16 mm, a wall thickness of 2 mm, and a height of 70 mm.
[0051] The catalyst packing layer has an inner diameter of 20 mm, a thickness of 2 mm, and a height of 690 mm. It is filled with 6 sets of grid plates and hollow tubular silica carriers for millimeter-level encapsulation of catalyst. The grid plates are 4 mm thick and have a hemispherical groove structure with 8 concave surfaces, each with a diameter of 5 mm. Hollow silica tubes with a diameter of 5 mm and a height of 4 mm are stacked on top. Each layer is 12 mm high. The diameter of the connecting hole in the groove of the bottom grid plate is 1.2 mm, decreasing by 0.15 mm from bottom to top, until the diameter of the connecting hole in the groove of the sixth grid plate is 0.45 mm. The total height of the 6 sets is 100 mm.
[0052] The discharge pipe has an inner diameter of 22mm, a thickness of 2mm, and a height of 40mm.
[0053] The inner diameter of the side return pipe is 8mm, the thickness is 2mm, the bottom pipe opening is 55mm higher than the feed pipe, the top pipe opening is 120mm higher than the bottom of the filler layer, the length is 30mm, and the height is 135mm.
[0054] Before operation, 8g of hollow spherical alumina carrier was weighed. The alumina carrier had a particle size of 3mm and an internal cavity diameter of 1.3mm. The cavity was filled with 1mg of Pd / Al₂O₃ with a particle size of 700nm and 1.5mg of Ni₂(Fe₂O₄)₃ with a particle size of 100nm, bonded to polyamide as magnetic spheres. The hollow tubular silica carrier and supporting material were uniformly filled into a fixed-fluidized bed reactor. The outer layer of the reactor consisted of a temperature control system and a magnetic field control system. The temperature control system was set to 50℃. The magnetic field control system consisted of surface-insulated wires tightly wound around a cylindrical iron ring. The wire current intensity was 3.4A, the coil had 100 turns, and the winding height was 140mm. The generated magnetic field had a magnetic induction intensity of B = 4.3 * 10⁻⁶. -4 T; The raw material liquid and the reaction gas are mixed and then transported to the fixed-fluidized bed reactor through the feed pipe. The gas-liquid mixture enters the inner cavity through the hollow tubular silica carrier channels. The catalyst powder inside is in a fluidized state under the flow of gas and liquid. With the assistance of the magnetic field control system, the magnetic microspheres enhance the disturbance of the catalyst. The gas-liquid mixture after the reaction diffuses out through the channels and is then transported to the gas collection bottle through the upper outlet for storage. After the reaction is completed, the reaction liquid is collected in the liquid collection tank for storage. After the liquid is drained, the device is disassembled, and the raw material storage tank and the fixed-fluidized bed reactor are cleaned and stored.
[0055] Application Example 1:
[0056] The anthraquinone hydrogenation reaction was evaluated using the reactor designed in Example 1. The operating steps were as shown in the example. The Pd loading of the Pd / Al2O3 used in Example 1 was 2.5%. The feed liquid and reactant gas were mixed and fed into the reactor at a flow rate of 200 ml / min. The anthraquinone working liquid was replaced every half hour. The collected working liquid was evaluated for the reaction, for a total of 4 evaluations. The hydrogenation efficiency was calculated using the hydrogenation efficiency calculation formula. The hydrogenation efficiencies obtained by the hollow spherical support for encapsulated catalyst used in Example 1 and the solid spherical support with the same external Pd catalyst loading under the same evaluation conditions are as follows: Figure 4 As shown in the comparison, the hollow spherical carrier has a higher hydrogenation efficiency.
[0057] In summary, the fixed-fluidized bed reactor of this invention is designed as a reactor with a hollow porous material that can be filled with a cavity structure. The hollow porous material is millimeter-sized, and the internal cavity is filled with a nano- or micron-sized catalyst. The hollow porous material has a mesoporous or microporous channel structure, allowing the gas-liquid mixture to enter the cavity through the material's channels and fully contact the catalyst. Under the buoyancy of the flowing mixture, the catalyst floats and fluidizes in the cavity. The confined microenvironment of the channels greatly increases the contact area between the reactants and the catalyst, enabling them to react fully and increasing the yield of the desired product. Encapsulating the catalyst in the cavity reduces loss. The external field control section can be composed of one or more of temperature control, magnetic field control, or microwave control. Temperature control provides the necessary thermal field for the reactor, the external magnetic field enhances the disturbance of the catalyst by controlling the magnetic microspheres inside the hollow carrier, and the microwave section uses an external microwave generator to cause vibrations in the gas or liquid phase to enhance the disturbance of the catalyst inside the hollow carrier.
Claims
1. A fixed-fluidized-bed reactor for heterogeneous catalytic reactions, characterized in that: From bottom to top, it includes the raw material feeding section, the catalyst filling section, and the reaction discharge section, with the circulation section and auxiliary control section on the side. The raw material feeding section consists of an injection tube, a jet tube, and a connecting tube. The injection tube has an inner diameter of 4-8 mm, a thickness of 1-4 mm, and a height of 30-70 mm. Its lower end connects to the raw material conveying system and can convey gas, liquid, or gas-liquid mixtures. The upper end of the injection tube has an upward-extending jet tube with a height of 35-120 mm. The outer layer of the jet tube is a connecting tube, the upper end of which is connected to the catalyst packing layer. The inner diameter of the connecting tube is 1.5-3 times that of the injection tube, the wall thickness is 1-4 mm, and the height is 1.5-2 times that of the injection tube. The upper part of the raw material feeding section is the catalyst filling section, which consists of a porous grid plate, a catalyst filling tube and a hollow porous material. The inner diameter of the catalyst filling tube is 15-30 mm, the wall thickness is 1-4 mm, and the height is 70-700 mm. 4-6 sets of porous grid plates and hollow porous materials are stacked inside the tube, and the stacking height is 2-6 times the inner diameter. The upper part of the catalyst filling section is the reaction discharge section, which is a discharge pipe connected to an external separation and collection system. The discharge pipe has an inner diameter of 19-24 mm, a thickness of 1-5 mm, and a height of 30-70 mm. The side end has a circulation section and an auxiliary control section. The circulation section is a reflux tube with an inner diameter of 5-10 mm and a thickness of 1-5 mm. The lower end of the tube is located inside the connecting tube of the raw material feed section, 50-120 mm higher than the raw material feed tube. The upper end of the tube is 60-210 mm higher than the bottom of the packing layer. The horizontal length of the reflux tube is 15-40 mm and the height is 70-300 mm. The outer layer of the reactor is an external field control system that controls temperature, magnetic field, or microwave; or a combination of these control systems. The reactor is filled with 10-170 ml of feed liquid. When the volume of the feed liquid increases or decreases beyond 10-170 ml, the height and inner diameter dimensions should be increased or decreased by 0.5-1.5 times the amount of increase or decrease in the feed liquid.
2. A fixed-fluidized bed reactor for heterogeneous catalytic reactions according to claim 1, characterized in that: The inner diameter of the jet tube gradually decreases linearly and uniformly from the inner diameter of the sample inlet tube to 0.4-0.8 times the inner diameter of the sample inlet tube.
3. A fixed-fluidized bed reactor for heterogeneous catalytic reactions according to claim 1, characterized in that: The bottom of the catalyst packing tube stack consists of a porous grid plate with the same diameter as the inner diameter of the packing tube and a thickness of 3-6 mm. The grid plate has evenly distributed grooves, which are hemispherical or conical in shape and 3-6 mm in diameter. The centers of each groove on the top cross-section of the grid plate are spaced 3-27 mm apart, and there are 4-16 grooves in total. The bottom of each groove has a connecting hole with a diameter of 0.1-1.5 mm. Hollow porous material is stacked on the grid plate. This hollow porous material refers to a millimeter-sized catalyst support with a cavity structure and mesopores or micropores, with a size ranging from 2-5 mm and an internal cavity diameter ranging from 0.5-2 mm. It includes alumina, silica, and carbon materials with hollow sphere or hollow tube structures. Nano- or micron-sized catalysts are filled into the cavities of the hollow porous material. 4-6 sets of porous grid plates and hollow porous material are stacked inside the tube, with 10-30 layers of material stacked on each grid plate. The hollow porous material is made of mm. The diameter of the connecting holes at the bottom of the concave surface of the stacked grid plates decreases by 0.1-0.35 mm from bottom to top. The diameter of the connecting holes at the bottom of the concave surface of the bottom grid plate is 0.4-1.5 mm, and the diameter of the connecting holes on the top grid plate is 0.1-1.2 mm.
4. A fixed-fluidized bed reactor for heterogeneous catalytic reactions according to claim 1, characterized in that: The magnetic field controls the movement of the magnetic microspheres. These microspheres are composite microspheres formed by combining magnetic inorganic particles with organic polymer materials. The magnetic inorganic particles include oxides of Fe, Co, and Ni, while the organic polymer materials include cellulose-based materials, polystyrene-based materials, or polyamide-based materials. The particle size of the composite microspheres is 50-1*10. 4 nm, with a mass of 0.5-3 mg, a charge of 10-50 C, and a magnetic field generated by a solenoid connected to a power source. The solenoid is composed of insulated wires tightly wound around a cylindrical iron ring. The solenoid has more than 60 turns of coil, and the voltage passing through it is 220 V, while the current passing through it is 0-10 A.
5. A fixed-fluidized bed reactor for heterogeneous catalytic reactions according to claim 1, characterized in that... Microwave control specifically involves: a microwave generator producing microwaves, which is connected to an external power supply and transformer. The power supply voltage is 220V, and the current passing through it is 0-10A. The transformer reduces the voltage to between 50-150V to reach the rated voltage of the microwave generator, thus protecting the instrument. The microwave frequency generated by the microwave generator is 1-5 MHz.