M- and p-cresol separating device

Abstract

The application belongs to the technical field of m-p-cresol separation, and discloses a m-p-cresol separation device, which comprises a gas-liquid-solid three-phase fluidized bed reactor, a micro-channel reaction tube and a high-pressure crystallization separator. A core-shell catalyst is arranged in the gas-liquid-solid three-phase fluidized bed reactor, and a plurality of sieve plates and an ultrasonic transducer assembly are arranged at the bottom. The inlet of the micro-channel reaction tube is connected with the outlet of the gas-liquid-solid three-phase fluidized bed reactor, and the micro-channel reaction tube is coated with a composite film. The inlet of the high-pressure crystallization separator is connected with the outlet of the micro-channel reaction tube, and the high-pressure crystallization separator is used for rapidly settling m-cresol crystals. The core-shell structure catalyst inhibits the dealkylation side reaction by passivating the acidic sites on the outer surface, solves the problem that the ionic liquid acid catalyst has strong corrosion to the equipment, needs alkali washing / water washing to remove acid, and the residual acid causes the dealkylation side reaction, and causes the problem of insufficient m-cresol purity. The gas-liquid-solid three-phase fluidized bed reactor is adopted, the gas-liquid contact efficiency is improved, and the utilization rate of the catalyst is improved.

Description

Technical Field

[0001] This utility model belongs to the field of m- and p-cresol separation technology, and specifically relates to a m- and p-cresol separation device. Background Technology

[0002] m- and p-cresols are important fine chemical intermediates. m-cresol has a wide range of applications, commonly used in the synthesis of pesticides, fragrances, and dyes, while p-cresol is an indispensable raw material for the synthesis of antioxidants and also has important applications in pharmaceuticals and pesticides. However, the atmospheric pressure boiling points of m- and p-cresols are very close, differing by less than 1°C, making it difficult to effectively separate mixtures of m- and p-cresols using traditional distillation methods. For example, Chinese invention patent application number CN201410226258.3 discloses a method for separating m- and p-cresol mixtures. Specifically, it discloses using a mixture of m- and p-cresol liquids and raw material gases as raw materials, employing a supported acidic ionic liquid as a catalyst to carry out an alkylation reaction in a fixed bed, separating the resulting alkylation products, and detert-butylating the mono-tert-butylcresol to obtain high-purity m- and p-cresols.

[0003] However, traditional fixed-bed reactors have low gas-liquid contact efficiency, and the ionic liquid acid catalysts are highly corrosive to the equipment, requiring alkali / water washing to remove acid. The residual acid triggers dehydrocarbonization side reactions, resulting in insufficient purity of m-cresol. Summary of the Invention

[0004] Based on this, this application provides a m- and p-cresol separation device to solve the problems of low gas-liquid contact efficiency in traditional fixed-bed reactors, strong corrosiveness of ionic liquid acid catalysts to equipment, the need for alkali / water washing to remove acid, and residual acid initiating dehydrocarbonization side reactions, resulting in insufficient m-cresol purity.

[0005] The technical solution to the above-mentioned technical problems in this application is as follows:

[0006] A m- and p-cresol separation device, comprising:

[0007] The system comprises a gas-liquid-solid three-phase fluidized bed reactor, a microchannel reaction tube, and a high-pressure crystallization separator. The gas-liquid-solid three-phase fluidized bed reactor contains a core-shell structured HZSM-5@Silicalite-1 molecular sieve catalyst. The bottom of the reactor is equipped with multi-layer sieve plates and an ultrasonic transducer. The multi-layer sieve plates ensure uniform gas-liquid distribution, and the ultrasonic transducer accelerates the dissolution of the raw materials. The inlet of the microchannel reaction tube is connected to the outlet of the gas-liquid-solid three-phase fluidized bed reactor, and the microchannel reaction tube is coated with a SiO2-Al2O3 composite membrane. The inlet of the high-pressure crystallization separator is connected to the outlet of the microchannel reaction tube, and the high-pressure crystallization separator is used for the rapid sedimentation of m-cresol crystals.

[0008] Preferably, the multiple sieve plate is made of 316L stainless steel with a surface treated by plasma nitriding.

[0009] Preferably, the multi-layer sieve plate includes a gas distribution plate and a liquid distributor. The gas distribution plate is disposed at the bottom of the gas-liquid-solid three-phase fluidized bed reactor and is located below the liquid inlet of the gas-liquid-solid three-phase fluidized bed reactor. The inlet of the liquid distributor is connected to the liquid inlet of the gas-liquid-solid three-phase fluidized bed reactor through a water pipe. The liquid distributor is provided with a plurality of perforations, and the perforations are vertically downward.

[0010] Preferably, the ultrasonic transducer assembly includes a central transducer and circumferential transducers. The central axis of the central transducer coincides with the central axis of the gas-liquid-solid three-phase fluidized bed reactor and is located in the middle of the gas-liquid-solid three-phase fluidized bed reactor. Several circumferential transducers are provided and located on the periphery of the reaction zone in the gas-liquid-solid three-phase fluidized bed reactor.

[0011] Preferably, the circumferential transducer is a longitudinal ultrasonic vibrator, and is arranged in a ring array around the reaction zone in the gas-liquid-solid three-phase fluidized bed reactor.

[0012] Preferably, the microchannel reaction tube is arranged in a serpentine pattern, and a corrugated baffle is slidably disposed inside the microchannel reaction tube, and the surface of the corrugated baffle is coated with polytetrafluoroethylene.

[0013] Preferably, the high-pressure crystallizer is provided with three temperature zones, namely a low-temperature zone, a medium-temperature zone, and a high-temperature zone. The low-temperature zone is close to the inlet of the high-pressure crystallizer, the high-temperature zone is far from the inlet of the high-pressure crystallizer, and the medium-temperature zone is located between the low-temperature zone and the high-temperature zone.

[0014] Preferably, the system further includes a waste heat recovery component, which includes a heat exchange pipe. The inlet of the heat exchange pipe is connected to the outlet of the gas-liquid-solid fluidized bed reactor and the outlet of the high-pressure crystallizer, respectively. The outlet of the heat exchange pipe is connected to the inlet of the high-pressure crystallizer for recovering reaction heat and preheating the raw material liquid.

[0015] Preferably, the waste heat recovery assembly includes a spiral coil heat exchanger, the inlet of which is connected to the outlet of the heat exchange pipe, and the outlet of which is connected to the inlet of the high-pressure crystallizer.

[0016] The technical solution adopted in this application can achieve the following beneficial effects:

[0017] 1. The core-shell structure HZSM-5@Silicalite-1 catalyst suppresses dehydrocarbonization side reactions by passivating the acidic sites on the outer surface. This solves the problem that ionic liquid acid catalysts are highly corrosive to equipment, requiring alkali / water washing to remove acid, and residual acid can trigger dehydrocarbonization side reactions, leading to insufficient purity of m-cresol.

[0018] 2. By using a gas-liquid-solid three-phase fluidized bed reactor instead of a traditional fixed bed reactor, the gas-liquid contact efficiency is improved, and the catalyst utilization rate is increased.

[0019] 3. Microchannel reactors reduce mixing time to the millisecond level, improving reaction conversion rate.

[0020] 4. Through multi-technology collaborative innovation (three-phase fluidized bed, microchannel reaction, high-pressure crystallization), the problems of low mass transfer efficiency, rapid catalyst deactivation, and high energy consumption in the traditional p-cresol separation process have been systematically solved. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall p-cresol separation device of this application.

[0022] The diagram shows: a gas-liquid-solid three-phase fluidized bed reactor 100, a multi-layer sieve plate 110, a gas distribution plate 111, a liquid distributor 112, an ultrasonic transducer 120, a central transducer 121, a circumferential transducer 122, a microchannel reaction tube 200, a corrugated baffle 210, a high-pressure crystallization separator 300, a low-temperature zone 310, a medium-temperature zone 320, a high-temperature zone 330, a waste heat recovery assembly 400, a heat exchange pipe 410, and a spiral coil heat exchanger 420. Detailed Implementation

[0023] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0024] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "end," "top," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0025] 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 application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] Please see Figure 1 This application provides a device for separating m- and p-cresol, comprising: a gas-liquid-solid three-phase fluidized bed reactor 100, a microchannel reaction tube 200, and a high-pressure crystallization separator 300. The gas-liquid-solid three-phase fluidized bed reactor 100 is equipped with a core-shell structured HZSM-5@Silicalite-1 molecular sieve catalyst (e.g., the HZSM-5@silicalite-1 core-shell structured molecular sieve disclosed in CN103708496B, which describes its preparation method and application). The bottom of the liquid-solid three-phase fluidized bed reactor 100 is provided with a multi-layer sieve plate 110 and an ultrasonic transducer 120. The multi-layer sieve plate 110 is used to ensure uniform gas-liquid distribution, and the ultrasonic transducer 120 is used to accelerate the dissolution of raw materials. The inlet of the microchannel reaction tube 200 is connected to the outlet of the gas-liquid-solid three-phase fluidized bed reactor 100, and the microchannel reaction tube 200 is coated with a SiO2-Al2O3 composite membrane. The inlet of the high-pressure crystallizer 300 is connected to the outlet of the microchannel reaction tube 200, and the high-pressure crystallizer 300 is used for rapid sedimentation of m-cresol crystals.

[0027] Specifically, gas-liquid-solid three-phase fluidization refers to a fluidization state in which solid particles are suspended in an upward gas-liquid flow, with a particle density much greater than that of the liquid. Gas (such as air) is introduced from the bottom of the gas-liquid-solid three-phase fluidization reactor, uniformly dispersed by multiple sieve plates 110, and then flows upward in parallel with the liquid (such as water or wastewater). Solid particles (a core-shell structured HZSM-5@Silicalite-1 molecular sieve catalyst) are suspended under the combined action of the gas and liquid flows, forming a fluidized bed. This flow state significantly increases the three-phase contact area and enhances mass transfer efficiency.

[0028] The microchannel reaction tube 200 has a size ranging from micrometers to millimeters and can form parallel, serpentine, spiral, or mesh structures (such as mesh structures composed of elliptical channels). The microchannel reaction tube 200 can be filled with microfilaments, microspheres, or reinforced hybrid structures such as octagonal protrusions. By coating the microchannel reaction tube 200 with a SiO2-Al2O3 composite film, the coefficient of friction is reduced.

[0029] The high-pressure crystallizer 300 includes a high-pressure reaction and crystallization unit. The high-pressure vessel for the high-pressure reaction is typically made of corrosion-resistant alloys (such as 316L stainless steel or titanium alloy) and can withstand ultra-high pressure environments of 500MPa to 550MPa. The crystallization separation unit includes a filter layer (such as a microporous filter plate), a water distributor, and a conical tank bottom, arranged sequentially from top to bottom on one side of the high-pressure vessel for solid-liquid separation and crystal collection. The high-pressure vessel is equipped with a temperature control system, including a jacketed heat exchanger or heating wire, to precisely regulate the internal temperature (e.g., high-temperature zone 330: 80-100℃, low-temperature zone 310: 20-30℃). Similarly, the high-pressure crystallizer 300 also includes a pressure regulation system, including a booster pump and a vacuum pump: connected to the crystallization unit via a three-way pipe, enabling seamless switching between ultra-high pressure pressurization and depressurization / sweating operations.

[0030] The core-shell structure of the HZSM-5@Silicalite-1 molecular sieve catalyst comprises a core layer (HZSM-5) and a shell layer (Silicalite-1). 1. The core layer is a high-silicon-to-aluminum ratio (SAR) HZSM-5 molecular sieve (SAR = 25-3000), exhibiting an MFI topology and containing a cross-channel system: cylindrical channels (0.54 × 0.56 nm) intersect perpendicularly with Z-shaped channels (0.52 × 0.58 nm), with the pore size extending to 0.9 nm at the intersections. This is the main distribution area for strong acid sites (Brønsted acids). The core layer regulates the acid quantity and strength through the SAR; for example, a low SAR (e.g., 25) provides high acid density but is prone to carbon deposition; a high SAR (e.g., 300) reduces strong acid sites and improves resistance to carbon deposition. 2. The shell layer is a pure silicon MFI molecular sieve (Silicalite-1), without the introduction of aluminum atoms, and therefore contains no acidic sites. Its pore size is the same as HZSM-5 (0.51nm to 0.58nm), but its surface is highly hydrophobic. By epitaxial growth, it covers the acidic sites on the outer surface of the core layer, suppressing macromolecular side reactions (such as dehydrocarbonization and coking). The shell thickness is usually 50nm to 100nm, which can be precisely controlled by the number of coatings (2 to 3 times).

[0031] Furthermore, the core-shell structured HZSM-5@Silicalite-1 molecular sieve catalyst is fed into the fluidized bed of the gas-liquid-solid three-phase fluidized bed reactor 100. Gas and liquid enter from the liquid inlet and gas inlet at the bottom of the reactor 100, respectively. After passing through multiple sieve plates 110, they are uniformly distributed and enter the fluidized bed together, contacting the core-shell structured HZSM-5@Silicalite-1 molecular sieve catalyst. The catalyst is accelerated and melted by the ultrasonic transducer 120, reaching the gas-liquid-solid separation chamber at the top of the reactor 100. The gas escapes from the gas outlet at the top of the reactor 100. The liquid-solid mixture, due to its density... The density difference returns to the bottom of the gas-liquid-solid three-phase fluidized bed reactor 100 through the self-circulation pipe (the circulation flow rate is driven by the density difference between the fluidized bed and the circulation pipe), and then the above steps are repeated to achieve dynamic circulation; at the same time, the fluid separated in the gas-liquid-solid separation chamber enters the microchannel reaction tube 200. In the serpentine or spiral flow channel, the fluid generates secondary flow and eddies due to the tortuous path and cross-sectional changes, breaking the laminar boundary layer. Through the turbulence effect, the mixing time is shortened to the millisecond level, realizing the rapid reaction of isobutylene and cresol. After the material is mixed and reacted again, it enters the high-pressure crystallization separator 300. Under the pressure ≥30MPa, the characteristic that the viscosity of cresol increases with pressure is used to make the m-cresol crystals settle rapidly and collect them.

[0032] Furthermore, by adjusting the internal pressure to a high pressure of 500MPa to 550MPa, the material undergoes a liquid-solid phase change, and selective separation is achieved by utilizing the difference in solubility. After separation, the crystals are slightly melted by reducing the pressure, and the impurities encapsulated inside (such as high-concentration mother liquor) are discharged through the pores, further improving the purity of the crystals. Then, the crystals are collected.

[0033] The technical solution of the m- and p-cresol separation device adopted in this application can achieve the following beneficial effects:

[0034] 1. The core-shell structure HZSM-5@Silicalite-1 catalyst suppresses dehydrocarbonization side reactions by passivating the acidic sites on the outer surface. This solves the problem that ionic liquid acid catalysts are highly corrosive to equipment, requiring alkali / water washing to remove acid, and residual acid can trigger dehydrocarbonization side reactions, leading to insufficient purity of m-cresol.

[0035] 2. By using a gas-liquid-solid three-phase fluidized bed reactor 100 to replace the traditional fixed bed reactor, the gas-liquid contact efficiency is improved, and the catalyst utilization rate is increased.

[0036] 3. Microchannel reactors reduce mixing time to the millisecond level, improving reaction conversion rate.

[0037] 4. Through multi-technology collaborative innovation (three-phase fluidized bed, microchannel reaction, high-pressure crystallization), the problems of low mass transfer efficiency, rapid catalyst deactivation, and high energy consumption in the traditional p-cresol separation process have been systematically solved.

[0038] Based on the above scheme, the multi-layer sieve plate 110 is made of 316L stainless steel with a surface treated by plasma nitriding. The surface treatment with plasma nitriding enhances corrosion resistance, thereby increasing its service life.

[0039] Furthermore, the multi-layer sieve plate 110 includes a gas distribution plate 111 and a liquid distributor 112. The gas distribution plate 111 is disposed at the bottom of the gas-liquid-solid three-phase fluidized bed reactor 100 and is located below the liquid inlet of the gas-liquid-solid three-phase fluidized bed reactor 100. The inlet of the liquid distributor 112 is connected to the liquid inlet of the gas-liquid-solid three-phase fluidized bed reactor 100 through a water pipe. The liquid distributor 112 is provided with a plurality of perforations, and the perforations are vertically downward.

[0040] Gas distribution plate 111 is used to uniformly distribute gas (such as air or syngas). Gas distribution plate 111 has a hole diameter of 0.5 mm to 1.5 mm, is made of 316L stainless steel and has a surface treated with plasma nitriding to improve corrosion resistance. Liquid distributor 112 works in conjunction with gas distribution plate 111 to uniformly introduce liquid into the fluidized bed through a perforated structure (hole diameter of 5 mm to 12 mm). The orifice direction is vertically downward to enhance mixing with the gas flow.

[0041] In a preferred embodiment of this application, the ultrasonic transducer assembly 120 includes a central transducer 121 and circumferential transducers 122. The central axis of the central transducer 121 coincides with the central axis of the gas-liquid-solid three-phase fluidized bed reactor 100 and is located in the middle of the gas-liquid-solid three-phase fluidized bed reactor 100. A plurality of circumferential transducers 122 are provided and are located on the periphery of the reaction zone in the gas-liquid-solid three-phase fluidized bed reactor 100.

[0042] The central transducer 121 is positioned to form the main radiation source of the sound field, ensuring uniform action on the materials in the bed. By placing it in the middle, it ensures that gas, liquid, and solid are all in contact, thus accelerating dissolution and uniform distribution. The circumferential transducer 122 works in conjunction with the central transducer 121 to enhance the coverage of the ultrasonic waves and avoid blind spots in the sound field.

[0043] The emitting surfaces of both the central transducer 121 and the circumferential transducer 122 must be completely submerged below the liquid surface, with the liquid level covering the top of the transducers by at least 10mm to 15mm to prevent damage to the equipment due to no-load conditions.

[0044] Furthermore, the circumferential transducer 122 is a longitudinal ultrasonic vibrator, and is arranged in a ring array around the reaction zone in the gas-liquid-solid three-phase fluidized bed reactor 100.

[0045] The circumferential transducer 122 is fixed to the inner wall of the reactor or the central support structure by means of high-strength adhesives, welding, etc., to ensure direct contact with the reaction medium. It is usually located in the middle of the reaction zone to ensure that the ultrasonic energy is fully applied to the gas-liquid-solid three-phase mixture, while avoiding interference to the sound field caused by bottom solid deposition or top gas escape.

[0046] In another preferred embodiment of this application, the microchannel reaction tube 200 is arranged in a serpentine pattern, a corrugated baffle 210 is slidably disposed inside the microchannel reaction tube 200, and the surface of the corrugated baffle 210 is coated with a polytetrafluoroethylene coating.

[0047] The corrugated baffle 210 reciprocates within the flow channel via a sliding component (manual or automatic drive; automatic drive utilizes levers, cylinders, etc.), causing periodic changes in the channel cross-section. As the corrugated baffle 210 moves, the upper and lower branch flow channel cross-sections alternately contract and expand. The fluid within the corrugated channel forms localized vortices due to these cross-sectional changes, further amplifying the turbulence effect when combined with the channel's own directional changes (e.g., sinusoidal / cosine curve paths). The fluid experiences periodic acceleration-deceleration within the alternating narrow and wide regions formed by the corrugated baffle 210 and the channel wall. Based on the laminar flow characteristics of microchannels, reducing channel size significantly shortens molecular diffusion distances, while the corrugated structure enhances chaotic mixing through secondary flow and recirculation zones, producing a turbulent-like mixing effect from the originally laminar flow. Furthermore, traditional fixed-section microchannels are prone to clogging due to increased resistance in materials with high solid content or high viscosity. The adjustable corrugated baffle 210 optimizes the local flow velocity and pressure distribution by dynamically adjusting the cross-sectional area of ​​the flow channel, thereby reducing the overall flow channel pressure gradient and thus reducing the system pressure drop.

[0048] Based on the above scheme, the high-pressure crystallizer 300 is provided with three temperature zones, namely a low-temperature zone 310, a medium-temperature zone 320, and a high-temperature zone 330. The low-temperature zone 310 is close to the inlet of the high-pressure crystallizer 300, the high-temperature zone 330 is far away from the inlet of the high-pressure crystallizer 300, and the medium-temperature zone 320 is located between the low-temperature zone 310 and the high-temperature zone 330.

[0049] High-temperature zone 330 (80-100℃): Located far from the inlet end of the high-pressure crystallizer 300, serving as the initial reaction / dissolution section, promoting material dissolution or inhibiting premature crystallization through high temperature; temperature control components (such as heating elements) are symmetrically distributed along the axis of the high-pressure crystallizer 300, with cylindrical heating elements symmetrically arranged on both sides along the third direction (perpendicular to the flow direction) to ensure temperature uniformity; Medium-temperature zone 320 (40-60℃): Located in the middle of the high-pressure crystallizer 300, serving as a transition section, inducing crystal nuclei formation through slow cooling. Heating and condensing elements are arranged alternately to form a dynamic temperature control interface to match the phase change requirements of the material; Low-temperature zone 310 (20-30℃): Closest to the inlet end of the high-pressure crystallizer 300, triggering crystal growth and separation through rapid cooling. Temperature control components (such as condensing elements) adopt a hollow cylindrical structure, uniformly distributed along the inner wall circumferentially, combined with a jacketed heat exchanger to achieve rapid cooling.

[0050] The material enters the low-temperature zone 310 through the inlet and is rapidly cooled. The reduced solubility at low temperatures triggers a supersaturated state, promoting initial crystal nucleation. The medium-temperature zone 320 (40-60℃) is matched with the metastable zone (5-7℃). Gradual cooling prevents uncontrolled nucleation and improves the uniformity of crystal size distribution (CSD). The high-temperature zone 330, located away from the inlet, reduces heat loss from the low-temperature zone 310. Combined with heat exchanger optimization, this achieves overall energy efficiency improvement. The gradient temperature control module achieves precise matching between the temperature field and material flow and phase change kinetics, providing an efficient and stable process foundation for high-pressure crystallization separation.

[0051] In another embodiment of this application, a waste heat recovery component 400 is further included. The waste heat recovery component 400 includes a heat exchange pipe 410. The inlet of the heat exchange pipe 410 is connected to the gas outlet of the gas-liquid-solid fluidized bed reactor and the outlet of the high-pressure crystallizer 300, respectively. The gas outlet of the heat exchange pipe 410 is connected to the inlet of the high-pressure crystallizer 300 for recovering reaction heat and preheating the raw material liquid.

[0052] The inlet end of heat exchange pipe 410 is connected to the high-temperature gas outlet or the side wall of the dense phase zone of the gas-liquid-solid fluidized bed reactor to capture the waste heat released during the reaction. Heat exchange pipe 410 is sealed via flange connection or plug-in resin collar (fluororubber sealing ring). The outlet end of heat exchange pipe 410 is connected to the feed liquid preheating section or gradient temperature control module inlet of the high-pressure crystallizer 300; for example, the low-temperature zone 310 (20-30℃) of the high-pressure crystallizer 300. A flange + elbow combination can be used at the pipe end to avoid direct impact on the separator's inner wall, while a spiral flow guiding structure (such as a stainless steel spiral flow guide rocker) is matched to enhance heat transfer efficiency. The connection between the inlet and outlet of heat exchange pipe 410 needs to comprehensively consider high-temperature sealing, fluid mixing efficiency, and equipment space limitations. Through flange / plug-in structure, spiral flow guiding design, and dynamic flow channel adjustment technology, efficient waste heat recovery and process stability are achieved.

[0053] Based on the above scheme, the waste heat recovery component 400 includes a spiral coil heat exchanger 420, the inlet of which is connected to the outlet of the heat exchange pipe 410, and the outlet of which is connected to the inlet of the high-pressure crystallizer 300.

[0054] The spiral coil heat exchanger 420 achieves counter-current heat exchange between hot and cold fluids through a spiral pipe design. Hot fluids (such as exhaust gas from a fluidized bed reactor) enter from the bottom inlet of the spiral tube and rise along the spiral channel; cold fluids (such as feed liquid) flow in the opposite direction from the shell side, forming counter-current contact. The spiral structure extends the fluid flow path and generates secondary circulation through the centrifugal force of the curved pipe, disrupting the laminar boundary layer and significantly improving the heat transfer coefficient. The crest and trough design of the spiral pipe creates strong turbulence in the fluid flow. Simultaneously, the scouring effect of the spiral structure reduces the tendency to scale; even if scale does accumulate, it can be quickly removed through chemical cleaning, resulting in low maintenance costs. Counter-current heat exchange and enhanced turbulence improve waste heat utilization. The spiral coil heat exchanger 420 achieves high-efficiency heat recovery and energy-saving goals through spiral counter-current, enhanced turbulence, and a compact structure, while also possessing high pressure resistance, low maintenance, and wide applicability.

[0055] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A device for separating m- and p-cresol, characterized in that, include: A gas-liquid-solid three-phase fluidized bed reactor is provided with a core-shell structured HZSM-5@Silicalite-1 molecular sieve catalyst. The bottom of the gas-liquid-solid three-phase fluidized bed reactor is provided with a multi-layer sieve plate and an ultrasonic transducer. The multi-layer sieve plate is used to make the gas and liquid uniformly distributed, and the ultrasonic transducer is used to accelerate the dissolution of the raw materials. A microchannel reaction tube, the inlet of which is connected to the outlet of the gas-liquid-solid three-phase fluidized bed reactor, the microchannel reaction tube being coated with a SiO2-Al2O3 composite membrane; and A high-pressure crystallizer, the inlet of which is connected to the outlet of the microchannel reaction tube, is used for the rapid sedimentation of m-cresol crystals.

2. The m- and p-cresol separation device as described in claim 1, characterized in that, The multi-layer sieve plate is made of 316L stainless steel with a surface treated by plasma nitriding.

3. The m- and p-cresol separation device as described in claim 2, characterized in that, The multi-layer sieve plate includes a gas distribution plate and a liquid distributor. The gas distribution plate is located at the bottom of the gas-liquid-solid three-phase fluidized bed reactor and below the liquid inlet of the gas-liquid-solid three-phase fluidized bed reactor. The inlet of the liquid distributor is connected to the liquid inlet of the gas-liquid-solid three-phase fluidized bed reactor through a water pipe. The liquid distributor is provided with several perforations, and the perforations are vertically downward.

4. The m- and p-cresol separation device as described in claim 1, characterized in that, The ultrasonic transducer assembly includes a central transducer and circumferential transducers. The central axis of the central transducer coincides with the central axis of the gas-liquid-solid three-phase fluidized bed reactor and is located in the middle of the gas-liquid-solid three-phase fluidized bed reactor. Several circumferential transducers are provided and located on the periphery of the reaction zone in the gas-liquid-solid three-phase fluidized bed reactor.

5. The m- and p-cresol separation device as described in claim 4, characterized in that, The circumferential transducer is a longitudinal ultrasonic vibrator, and it is arranged in a ring array around the reaction zone in the gas-liquid-solid three-phase fluidized bed reactor.

6. The m- and p-cresol separation apparatus as described in claim 1, characterized in that, The microchannel reaction tube is arranged in a serpentine pattern, and a corrugated baffle is slidably disposed inside the microchannel reaction tube, with the surface of the corrugated baffle coated with polytetrafluoroethylene.

7. The m- and p-cresol separation apparatus as described in claim 1, characterized in that, The high-pressure crystallizer is equipped with three temperature zones: a low-temperature zone, a medium-temperature zone, and a high-temperature zone. The low-temperature zone is close to the inlet of the high-pressure crystallizer, the high-temperature zone is far from the inlet of the high-pressure crystallizer, and the medium-temperature zone is located between the low-temperature zone and the high-temperature zone.

8. The m- and p-cresol separation apparatus as described in claim 1, characterized in that, It also includes a waste heat recovery component, which includes a heat exchange pipe. The inlet of the heat exchange pipe is connected to the outlet of the gas-liquid-solid fluidized bed reactor and the outlet of the high-pressure crystallizer, respectively. The outlet of the heat exchange pipe is connected to the inlet of the high-pressure crystallizer for recovering reaction heat and preheating the raw material liquid.

9. The m- and p-cresol separation apparatus as described in claim 8, characterized in that, The waste heat recovery assembly includes a spiral coil heat exchanger, the inlet of which is connected to the outlet of the heat exchange pipeline, and the outlet of which is connected to the inlet of the high-pressure crystallizer.

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