Liquid-solid circulating fluidized bed-moving bed coupling reaction system and application thereof

Abstract

The application discloses a liquid-solid circulating fluidized bed-moving bed coupling reaction system and application, the coupling reaction system of the application includes a liquid-solid circulating fluidized bed reactor and a moving bed reactor, the liquid-solid circulating fluidized bed reactor mainly includes an upflow bed reactor, a liquid-solid separator, a stock bin and a particle feeding inclined pipe which are sequentially communicated through pipelines, the liquid phase outlet of the liquid-solid circulating fluidized bed is connected with the liquid phase inlet of the moving bed reactor, and the moving bed reactor mainly includes a moving bed shell, a particle inlet, a liquid phase inlet, a central pipe, a moving bed particle bed layer, a filter screen, a particle outlet and a moving bed liquid phase outlet; when the coupling reaction system is applied to the process of directly oxidizing propylene (chloropropylene) into propylene oxide (epichlorohydrin) by hydrogen peroxide, the hydrogen peroxide concentration at the system outlet can be controlled below 50 ppm, and the particle loss rate is lower than 0.2%. The loss rate of the catalyst is remarkably reduced, the flow rate of the reactant is improved, the residence time is shortened, the production capacity of the device is improved, and the production cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of multiphase reaction engineering and chemical production technology, specifically relating to a liquid-solid circulating fluidized bed-moving bed coupled reaction system and its application in the preparation of epoxy compounds by direct oxidation with hydrogen peroxide. Background Technology

[0002] The liquid-solid circulating fluidized bed reactor (LCBFR) is a novel reactor characterized by a large liquid-solid phase contact area and high heat and mass transfer rates, effectively enhancing the reaction process. LCBFR couples two different fluidized bed types: rapid liquid-solid fluidized bed and conventional liquid-solid fluidized bed. This allows for a high degree of coupling between the reaction and regeneration processes, and enables online replacement of particulate materials or catalysts within the system, achieving continuous production operation and increasing the plant's operating efficiency and safety stability. Based on these advantages, LCBFR has been successfully applied in wastewater biological treatment, phenol removal from phenol-containing wastewater, lactic acid fermentation and separation, protein extraction, and the hydrogen peroxide process for the production of propylene oxide and epichlorohydrin, demonstrating significant advantages.

[0003] The liquid-solid circulating fluidized bed mainly consists of an upward bed, a liquid-solid separator, a hopper, and a feed control valve. Within the riser reactor, it is a rapid liquid-solid fluidization zone. In the upward bed, the liquid phase is continuous, and the particulate phase is dispersed. The particles move upwards in parallel with the liquid phase under the drag force of the liquid, ensuring full contact and reaction between the liquid and solid phases during this movement. This system is suitable for reactions with low particle concentrations and fast reaction rates. The outlet of the upward bed is connected to the inlet of the liquid-solid separator for separation of the liquid and particulate phases. The liquid-solid separator can be a settling separator or a hydrocyclone separator, etc. The liquid phase flows out from the top of the separator, while the particulate phase enters the hopper from the bottom. The upper part of the hopper is a dilute phase zone, and the lower part is a dense phase zone. In the dilute phase zone, particles move downwards while the liquid phase moves upwards, resulting in countercurrent contact between the liquid and solid phases, which cleans the particles. The dense phase zone is a traditional liquid-solid fluidized bed, suitable for processes with high particle concentrations and slow reaction rates. The bottom of the silo is connected to the bottom of the ascending bed reactor, and a feed control valve is installed on the connecting pipe to control the particle concentration in the ascending bed, enabling particle circulation. Within the entire circulating fluidized bed system, particles circulate within the system. Different liquid phase materials can be introduced into the ascending bed and the silo, achieving a high degree of coupling and integration of the two reaction processes in the ascending bed and the silo. This is particularly suitable for processes requiring frequent switching, such as reaction-regeneration and adsorption-desorption. In the field of chemical production, liquid-solid circulating fluidized bed reactors have been successfully applied in processes such as the direct oxidation of propylene with hydrogen peroxide to produce propylene oxide and the direct oxidation of hydrogen peroxide to produce epichlorohydrin.

[0004] A moving bed reactor is a type of reactor capable of gas-solid or liquid-solid phase reactions. Fixed particulate material or catalyst is continuously added to the top of the reactor; as the reaction proceeds, the solid material gradually moves downwards and is eventually discharged continuously from the bottom. Compared to a fixed bed reactor, this type of reactor allows for continuous addition and removal of solid particles or catalyst. Compared to a fluidized bed reactor, it has lower requirements for catalyst strength. This type of reactor was first used in pressurized gasifiers (Lurgi furnaces) and has subsequently been successfully applied in industrial processes such as continuous reforming and xylene isomerization. In addition, moving beds are also a typical filtration device. In a moving bed, the particles continuously move downwards under their own gravity. The fluid containing fine particles to be filtered is intercepted by these particles and moves out of the bed along with them. The particles carrying fine particles can be recycled after passing through a regeneration system that separates them from the fine particles. They can be added back from the top of the moving bed to continue capturing new materials containing fine particles. A dynamic balance is formed in the moving bed between continuous dust deposition and continuous dust removal, achieving continuous and stable operation while ensuring high filtration efficiency. According to the gas-solid (liquid-solid) two-phase flow pattern, moving beds can be classified into cross-flow (particles flow downwards, gas / liquid flows horizontally), parallel flow (both gas / liquid and particles move downwards), counter-flow (gas / liquid flow and particle flow are in opposite directions), and mixed flow (simultaneously having both co-current and counter-current bed layers).

[0005] Invention patent CN115745918B discloses an HPPO process for producing propylene oxide using a liquid-solid circulating fluidized bed reaction-regeneration system. This process innovatively proposes using a liquid-solid circulating fluidized bed reaction-regeneration system instead of a traditional tubular fixed-bed reactor, avoiding the bed "hot spots" that easily occur in fixed-bed reactors, thus improving the reaction rate. Furthermore, it achieves a high degree of coupling between the reaction and regeneration processes. Microspherical TS-1 catalyst is used in an upward-flowing bed reactor to realize the direct oxidation of propylene with hydrogen peroxide to produce propylene oxide. In the feed silo, a loosening liquid methanol cleaning method is used to remove reaction products between catalyst particles and within the pores, achieving catalyst regeneration and extending catalyst lifespan. Simultaneously, the catalyst can be replaced online in the feed silo, achieving external catalyst regeneration and ensuring the continuity and stability of production operations.

[0006] Invention patent CN115894400B discloses a process for directly oxidizing propylene chloride to epichlorohydrin using a liquid-solid circulating fluidized bed reactor. This process uses a liquid-solid circulating fluidized bed reactor instead of a tubular fixed-bed reactor or a stirred tank reactor. The liquid-solid rapid fluidized bed reactor enhances heat and mass transfer between the liquid and solid phases, reduces backmixing, significantly increases the reaction rate, shortens the reaction time, suppresses side reactions such as hydrolysis and alcoholysis of the generated epichlorohydrin, and increases the selectivity of epichlorohydrin. Furthermore, the catalyst silo allows for catalyst cleaning and online replacement, avoiding frequent start-up and shutdown operations. Both of these invention patents use a liquid-solid circulating fluidized bed reactor instead of a traditional tubular fixed-bed reactor or a continuous stirred tank reactor, increasing the epoxidation rate of propylene or propylene chloride and enabling catalyst regeneration and replacement, thus achieving long-term stable operation of the equipment. To ensure that the residual hydrogen peroxide at the reactor outlet does not pose a danger to subsequent processes, the hydrogen peroxide concentration is generally required to be below 500 ppm. Therefore, upward bed reactors are typically designed to be at least 20 m high, and sometimes even as high as 50 m. However, in actual operation, it has been found that most of the epoxidation reaction occurs in the lower and middle parts of the upward bed reactor. The upper and middle parts of the reactor have relatively low hydrogen peroxide concentrations, resulting in a slow reaction rate and low space utilization efficiency. Even with a designed high reactor height, excessively high hydrogen peroxide concentrations at the reactor outlet can still occur in practice. Furthermore, since propylene or allyl chloride epoxidation processes generally use spherical titanium-silicon molecular sieve catalysts with a particle size of 50-150 μm, some fine particles can easily escape from the liquid-solid separator, leading to significant catalyst loss or blockage of subsequent systems. Currently, the application of liquid-solid circulating fluidized bed reactors for the epoxidation of propylene or allyl chloride and other olefins faces problems such as easily excessively high hydrogen peroxide concentrations at the reactor outlet and catalyst particle loss. Summary of the Invention

[0007] Therefore, the purpose of this invention is to provide a liquid-solid circulating fluidized bed-moving bed coupled reaction system and its application in the preparation of epoxy compounds by direct oxidation with hydrogen peroxide. The coupled reaction system of this application can ensure that the hydrogen peroxide concentration at the system outlet is less than 50 ppm and the catalyst particle loss rate is less than 0.2%, which can reduce catalyst loss, increase reactor throughput, increase reactor capacity, and improve the safety of equipment operation.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, the present invention provides a liquid-solid circulating fluidized bed-moving bed coupled reaction system, comprising a liquid-solid circulating fluidized bed reactor 10 and a moving bed reactor 20. The liquid-solid circulating fluidized bed reactor 10 mainly includes an ascending bed reactor 11, a liquid-solid separator 12, a hopper 13, and a particle feed inclined pipe 14 connected sequentially by pipes. The bottom of the ascending bed reactor 11 is provided with a reactant inlet and a hydrogen peroxide inlet, and a heat exchange system is provided on the side wall of the ascending bed reactor 11. The top of the liquid-solid separator 12 is provided with a liquid-solid circulating fluidized bed liquid phase outlet 15, which is connected to the liquid phase inlet 24 of the moving bed reactor 20 by a pipe. The moving bed reactor 20 mainly includes a moving bed shell 21, a particle inlet 23, a liquid phase inlet 24, a central pipe 25, a moving bed particle bed 26, a filter screen 27, and a particle outlet. The moving bed liquid phase outlet 29 and the moving bed shell 21 are connected by a heat exchange system on the side wall. The liquid phase inlet 24 is located at the top center of the moving bed shell 21, and the moving bed liquid phase outlet 29 is located at the bottom center of the moving bed shell 21. The particle inlet 23 is located on the side of the liquid phase inlet 24. The particle inlet 23 penetrates the moving bed shell 21 and is connected to the top of the interlayer of the concentric cylindrical filter screen 27. The bottom of the interlayer of the concentric cylindrical filter screen 27 is connected to the particle outlet 28 located at the bottom of the moving bed shell 21. A baffle is provided on the top cross-section of the inner circle of the concentric cylindrical filter screen 27. The interior of the concentric cylindrical filter screen 27 forms a central tube 25. The bottom of the central tube 25 is connected to the moving bed liquid phase outlet 29. The moving bed liquid phase outlet 29 is connected to the product separation and purification system, and the particle outlet 28 is connected to the particle processing system.

[0010] Based on the above technical solution, the liquid-solid separator 12 is further described as a sedimentation separator, a filtration separator, or a hydrocyclone separator.

[0011] Based on the above technical solution, a flow control valve is further provided on the feed inclined tube 14.

[0012] Based on the above technical solution, a regenerated liquid inlet is further provided at the bottom of the silo 13.

[0013] Based on the above technical solution, further, the particles are filled into the interlayer of the concentric cylindrical filter screen 27 to form a moving bed particle bed 26.

[0014] Based on the above technical solution, the main functions of the moving bed reactor 20 are: firstly, to further increase the reaction depth, ensure that the remaining trace reactants are completely converted, make full use of raw materials, increase product yield, and improve the safety and continuity of the device operation; secondly, to filter out the fine particles carried out by the upstream liquid-solid sedimentation separator.

[0015] Secondly, the present invention provides the application of the above-mentioned liquid-solid circulating fluidized bed-moving bed coupled reaction system in the preparation of epoxide alkane compounds by direct oxidation with hydrogen peroxide.

[0016] Based on the above technical solution, the epoxy alkane compounds further include propylene oxide, epichlorohydrin, epichlorohydrin, and methyl epichlorohydrin.

[0017] Based on the above technical solution, the specific process for preparing epoxide alkane compounds by direct hydrogen peroxide oxidation further includes the following steps: S1: Olefin compounds, solvents, and hydrogen peroxide are introduced into the bottom of the rising bed reactor 11 and contacted with the catalyst to carry out an epoxidation reaction. After liquid-solid separation in the liquid-solid separator 12, the liquid phase product flows out through the liquid phase outlet 15 of the liquid-solid circulating fluidized bed. The catalyst particles settle into the silo 13, and methanol regeneration liquid is introduced through the regeneration liquid inlet at the bottom of the silo 13 to realize catalyst regeneration. S2: The catalyst particles are introduced into the particle inlet 23 of the moving bed reactor, and the liquid phase product described in step S1 is introduced into the liquid phase inlet 24 of the moving bed reactor. The product enters the moving bed central tube 25 through the moving bed liquid phase annular region 22, filter screen 27, and moving bed particle bed 26. The fine catalyst particles carried in the liquid phase product are intercepted by the moving bed particle bed 26. The resulting reaction liquid phase mixture with low hydrogen peroxide residue and low particle carrying capacity enters the subsequent product separation and purification system through the liquid phase outlet 29. S3: Moving bed catalyst particles carrying trace amounts of catalyst particles escaping from the liquid-solid circulating fluidized bed enter the subsequent moving bed particle processing system or return to the liquid-solid circulating fluidized bed silo through particle outlet 28.

[0018] Based on the above technical solution, the olefin compounds mentioned in step S1 further include propylene, chloropropylene, n-butene, and methylallyl chloride.

[0019] Based on the above technical solution, further, the solvent mentioned in step S1 is at least one of methanol, ethanol, acetone, acetonitrile, chloroform, 1,4-dioxane, isopropanol, and tert-butanol.

[0020] Based on the above technical solution, further, in step S1, the effective height of the ascending bed reactor 11 is 5~15 m, and the liquid residence time is controlled to be 5~20 min; the apparent liquid velocity of the liquid phase mixture in the ascending bed reactor 11 is 20~100 m / h; the catalyst is TS-1 catalyst, the average particle size of the catalyst particles is 20~1000 μm, and the particle density is 500~3000 kg / m³. 3The hydrogen peroxide raw material used is hydrogen peroxide with a mass fraction of 10-60%, the molar ratio of hydrogen peroxide to olefin compounds is 1:1-1:6, the molar ratio of hydrogen peroxide to solvent is 1:2-1:10, the mass concentration of catalyst in the ascending bed reactor 11 is 0.1-5%, the reactor temperature is controlled at 10-60 ℃, and the reaction pressure is 0.1-5 MPa.

[0021] Based on the above technical solution, further, the catalyst particles used in the moving bed reactor in step S2 are TS-1 catalyst particles with an average particle size of 0.05~10 mm.

[0022] Based on the above technical solution, further, the movement speed of the catalyst particles in the moving bed reactor in step S2 is controlled by the control valve of the particle outlet 28 of the moving bed reactor or the slurry pump, and the apparent flow velocity of the particles in the bed is 0.1~100 m / h.

[0023] Based on the above technical solution, further, the operating pressure of the moving bed reactor in step S2 is 0.1~5MPa, and the reaction temperature is 10~60℃.

[0024] Compared with the prior art, the present invention has the following beneficial effects: The liquid-solid circulating fluidized bed-moving bed coupled reaction system of the present invention can achieve a hydrogen peroxide residue of less than 50 ppm and a catalyst particle loss rate of less than 0.2% in the process of producing epichlorohydrin by direct oxidation of propylene with hydrogen peroxide. The same effect can be achieved in the process of producing epichlorohydrin by direct oxidation of chloropropylene with hydrogen peroxide, which improves the safety of the equipment operation, reduces the catalyst loss rate, and can appropriately increase the equipment throughput, and has very good application prospects. Attached Figure Description

[0025] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0026] Figure 1 This is a schematic diagram of the liquid-solid circulating fluidized bed-moving bed coupled reaction system of the present invention, wherein 10-liquid-solid circulating fluidized bed reactor, 11-rising bed reactor, 12-liquid-solid separator, 13-hopper, 14-particle feed inclined tube, 15-liquid-solid circulating fluidized bed liquid phase outlet, 20-moving bed reactor, 21-moving bed shell, 22-moving bed liquid phase annular region, 23-particle inlet, 24-liquid phase inlet, 25-central tube, 26-moving bed particle bed, 27-filter screen, 28-particle outlet, 29-moving bed liquid phase outlet. Detailed Implementation

[0027] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0028] Example 1 This embodiment provides a liquid-solid circulating fluidized bed-moving bed coupled reaction system and its application in the direct oxidation of propylene with hydrogen peroxide to produce propylene oxide. The liquid-solid circulating fluidized bed-moving bed coupled reaction system includes a liquid-solid circulating fluidized bed reactor 10 and a moving bed reactor 20. The liquid-solid circulating fluidized bed reactor 10 mainly includes an upward bed reactor 11, a liquid-solid separator 12, a hopper 13, and a particle feed inclined pipe 14, which are connected in sequence by pipelines. A flow control valve is installed on the feed inclined pipe 14. The bottom of the upward bed reactor 11 is equipped with... The reactor 11 has a reactant inlet and a hydrogen peroxide inlet. A heat exchange system is installed on the side wall of the rising bed reactor 11. A regenerated liquid inlet is located at the bottom of the hopper 13. The liquid-solid separator 12 is a settling separator. A liquid-solid circulating fluidized bed liquid phase outlet 15 is located at the top of the liquid-solid separator 12. The liquid-solid circulating fluidized bed liquid phase outlet 15 is connected to the liquid phase inlet 24 of the moving bed reactor 20 via a pipeline. The moving bed reactor 20 mainly includes a moving bed shell 21, a moving bed liquid phase annular region 22, a particle inlet 23, a liquid phase inlet 24, and a central tube 25. The moving bed includes a particle bed 26, a filter screen 27, a particle outlet 28, and a moving bed liquid outlet 29. A heat exchange system is installed on the side wall of the moving bed shell 21. The liquid inlet 24 is located at the top center of the moving bed shell 21, and the liquid outlet 29 is located at the bottom center of the moving bed shell 21. Particle inlets 23 are located on both sides of the liquid inlet 24, penetrating the moving bed shell 21 and communicating with the top of the interlayer of the concentric cylindrical filter screen 27. The bottom of the interlayer of the concentric cylindrical filter screen 27 is connected to the bottom of the moving bed shell 21. The particle outlet 28 is connected to the moving bed particle bed 26 after the particles are filled in the interlayer of the concentric cylindrical filter screen 27. A baffle is provided on the top cross-section of the inner circle of the concentric cylindrical filter screen 27 to divert the liquid entering from the liquid phase inlet 24 to the moving bed liquid phase annular region 22. The interior of the concentric cylindrical filter screen 27 forms a central tube 25. The bottom of the central tube 25 is connected to the moving bed liquid phase outlet 29. The moving bed liquid phase outlet 29 is connected to the product separation and purification system, and the particle outlet 28 is connected to the particle processing system.

[0029] The production of propylene oxide using the above-mentioned liquid-solid circulating fluidized bed-moving bed coupled reaction system via direct oxidation of propylene with hydrogen peroxide includes the following steps: S1: Propylene, methanol, and hydrogen peroxide are introduced into the bottom of the ascending bed reactor 11 and contacted with the catalyst for epoxidation. After liquid-solid separation in the liquid-solid separator 12, the liquid product flows out through the liquid-solid circulating fluidized bed liquid outlet 15. The catalyst particles settle into the silo 13, and methanol regeneration liquid is introduced through the regeneration liquid inlet at the bottom of the silo 13 to regenerate the catalyst. The effective height of the ascending bed reactor 11 is 8 m, and the liquid residence time is controlled at 16 min. The apparent liquid velocity of the liquid mixture in the ascending bed reactor 11 is 30 m / h. The average particle size of the TS-1 catalyst particles is 75 μm, and the particle density is 2000 kg / m³. 3 The hydrogen peroxide feedstock used is 50% by mass, the molar ratio of hydrogen peroxide to propylene is 1:4, the molar ratio of hydrogen peroxide to methanol is 1:7.5, the catalyst concentration in the rising bed reactor 11 is 0.6%, the reactor temperature is controlled at 35℃, and the reaction pressure is 3 MPa. S2: The catalyst particles (TS-1 catalyst particles) are introduced into the particle inlet 23 of the moving bed reactor, and the apparent flow rate of the catalyst particle bed in the moving bed reactor is controlled at 0.5 m / h. S3: The liquid product described in S1 is introduced into the liquid inlet 24 of the moving bed reactor. It enters the moving bed central tube 25 through the moving bed liquid annular region 22, filter screen 27, and moving bed particle bed 26. The operating pressure of the moving bed reactor 20 is 2.8 MPa, and the reaction temperature is 35℃. After the liquid product passes through the moving bed 26, the residual hydrogen peroxide reacts further. The fine catalyst particles it carries are intercepted by the moving bed particle bed 26. At the liquid outlet 29, a reaction liquid mixture with low hydrogen peroxide residue and low particle carrying capacity is obtained, which enters the subsequent product separation and purification system. S4: Moving bed catalyst particles carrying trace amounts of catalyst particles escaping from the liquid-solid circulating fluidized bed enter the subsequent moving bed particle processing system or return to the liquid-solid circulating fluidized bed silo through particle outlet 28.

[0030] According to the above embodiments, samples were taken at the liquid phase outlet 15 of the liquid-solid circulating fluidized bed and the liquid phase outlet 29 of the moving bed to analyze the residual amount of hydrogen peroxide and the mass of the contained catalyst particles in the liquid phase product. The catalyst particle overflow rate was calculated based on the raw material composition and the catalyst concentration in the upward bed reactor. The results show that using the above-mentioned liquid-solid circulating fluidized bed-moving bed coupled reaction system to directly oxidize propylene with hydrogen peroxide to produce propylene oxide can ensure that the hydrogen peroxide concentration at the reaction system outlet is below 50 ppm and the catalyst particle loss rate is below 0.2%.

[0031] Example 2 Similar to Example 1, except that the flow rate of the liquid reactants in the ascending bed reactor is increased to 60 m / h, which shortens the residence time to 8 min, thus doubling the reactor's capacity, while other operating conditions remain unchanged.

[0032] Example 3 Similar to Example 1, except that the propylene in the liquid phase reactant in the ascending bed reactor is replaced with allyl chloride, the reaction pressure is adjusted to 0.3 MPa, the reaction product is epichlorohydrin, and other operating conditions remain unchanged.

[0033] Example 4 Similar to Example 3, except that the flow rate of the liquid reactants in the rising bed reactor is increased to 60 m / h, and the residence time is shortened to 8 min, thus doubling the reactor's capacity, while other operating conditions remain unchanged.

[0034] The hydrogen peroxide concentration and particle loss rate at the liquid phase outlet of the liquid-solid circulating fluidized bed and the liquid phase outlet of the moving bed in Examples 1-4 were calculated respectively, and the results are shown in Table 1 below.

[0035] Table 1 Comparison of hydrogen peroxide concentration and particle loss rate at different locations in Examples 1-4

[0036] As shown in Table 1, for the two processes of direct oxidation of propylene with hydrogen peroxide to produce propylene oxide and direct oxidation of chloropropylene with hydrogen peroxide to produce epichlorohydrin, the use of a liquid-solid circulating fluidized bed-moving bed coupled reaction system can ensure that the hydrogen peroxide concentration at the system outlet is below 50 ppm and the catalyst loss rate is below 0.2%. Compared with using a liquid-solid circulating fluidized bed alone, in a reactor of the same size, the liquid velocity of the reactants can be increased, the reactor capacity can be increased, and the equipment investment can be reduced. At the same time, it can also achieve the separation and recovery of fine catalysts. That is, using the coupled reaction system of the present invention can increase the safety of the equipment, increase the production capacity of the equipment, reduce catalyst loss, and improve the economic benefits of the equipment.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid-solid circulating fluidized bed-moving bed coupled reaction system, characterized in that, This includes liquid-solid circulating fluidized bed reactors and moving bed reactors. The liquid-solid circulating fluidized bed reactor mainly comprises an upward-flowing bed reactor, a liquid-solid separator, a silo, and a particle feed inclined tube, all connected sequentially by pipes. The bottom of the upward-flowing bed reactor has a reactant inlet and a hydrogen peroxide inlet, and a heat exchange system is installed on its sidewall. The top of the liquid-solid separator has a liquid-solid circulating fluidized bed liquid phase outlet, which is connected to the liquid phase inlet of the moving bed reactor via a pipe. The moving bed reactor mainly includes a moving bed shell, a particle inlet, a liquid phase inlet, a central tube, a moving bed particle bed, a filter screen, a particle outlet, and a moving bed liquid phase outlet. A heat exchange system is installed on the side wall of the moving bed shell. The liquid phase inlet is located at the top center of the moving bed shell, and the liquid phase outlet is located at the bottom center of the moving bed shell. The particle inlet is located next to the liquid phase inlet. The particle inlet penetrates the moving bed shell and is connected to the top of the interlayer of the concentric cylindrical filter screen. The bottom of the interlayer of the concentric cylindrical filter screen is connected to the particle outlet located at the bottom of the moving bed shell. A baffle is installed on the top cross-section of the inner circle of the concentric cylindrical filter screen. The inside of the concentric cylindrical filter screen forms a central tube, and the bottom of the central tube is connected to the liquid phase outlet of the moving bed. The liquid phase outlet of the moving bed is connected to the product separation and purification system, and the particle outlet is connected to the particle processing system.

2. The liquid-solid circulating fluidized bed-moving bed coupled reaction system according to claim 1, characterized in that, The liquid-solid separator is one of a sedimentation separator, a filtration separator, or a hydrocyclone separator; a flow control valve is installed on the feed inclined pipe; and a regenerated liquid inlet is installed at the bottom of the silo.

3. The liquid-solid circulating fluidized bed-moving bed coupled reaction system according to claim 1, characterized in that, The moving bed particle bed is formed by filling the interlayer of the concentric cylindrical filter screen with particles.

4. The application of the liquid-solid circulating fluidized bed-moving bed coupled reaction system according to any one of claims 1-3 in the preparation of epoxide alkane compounds by direct oxidation with hydrogen peroxide.

5. The application according to claim 4, characterized in that, The epoxy alkane compounds include propylene oxide, epichlorohydrin, epichlorohydrin, and methyl epichlorohydrin.

6. The application according to claim 5, characterized in that, The specific process for preparing epoxide alkane compounds by direct hydrogen peroxide oxidation includes the following steps: S1: Olefin compounds, solvents, and hydrogen peroxide are introduced into the bottom of the rising bed reactor and contacted with the catalyst to carry out an epoxidation reaction. After liquid-solid separation in the liquid-solid separator, the liquid phase product flows out through the liquid phase outlet of the liquid-solid circulating fluidized bed. The catalyst particles settle into the silo, and methanol regeneration liquid is introduced through the regeneration liquid inlet at the bottom of the silo to regenerate the catalyst. S2: The catalyst particles are introduced into the particle inlet of the moving bed reactor, and the liquid phase product described in step S1 is introduced into the liquid phase inlet of the moving bed reactor. The product enters the moving bed central tube through the liquid phase annular region of the moving bed via the filter screen and the moving bed particle bed. The fine catalyst particles carried in the liquid phase product are intercepted by the moving bed particle bed. The resulting reaction liquid phase mixture with low hydrogen peroxide residue and low particle carrying capacity enters the subsequent product separation and purification system through the liquid phase outlet. S3: Moving bed catalyst particles carrying trace amounts of catalyst particles escaping from the liquid-solid circulating fluidized bed enter the subsequent moving bed particle processing system or return to the liquid-solid circulating fluidized bed silo from the particle outlet.

7. The application according to claim 6, characterized in that, The olefinic compounds mentioned in step S1 include propylene, chloropropylene, n-butene, and methylallyl chloride; the solvent is at least one of methanol, ethanol, acetone, acetonitrile, chloroform, 1,4-dioxane, isopropanol, and tert-butanol.

8. The application according to claim 6, characterized in that, In step S1, the effective height of the rising bed reactor is 5–15 m, and the residence time of the liquid is controlled to be 5–20 min; the apparent liquid velocity of the liquid phase mixture in the rising bed reactor is 20–100 m / h; the catalyst is TS-1 catalyst, with an average particle size of 20–1000 μm and a particle density of 500–3000 kg / m³. 3 The reactor uses hydrogen peroxide with a mass fraction of 10-60%, a molar ratio of hydrogen peroxide to olefins of 1:1-1:6, a molar ratio of hydrogen peroxide to solvent of 1:2-1:10, and a catalyst mass concentration of 0.1-5% in the ascending bed reactor. The reactor temperature is controlled at 10-60 °C, and the reaction pressure is 0.1-5 MPa.

9. The application according to claim 6, characterized in that, The catalyst particles used in the moving bed reactor described in step S2 are TS-1 catalyst particles with an average particle size of 0.05~10 mm and an apparent particle flow rate of 0.1~100 m / h.

10. The application according to claim 6, characterized in that, The operating pressure of the moving bed reactor described in step S2 is 0.1~5 MPa, and the reaction temperature is 10~60℃.

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