A recovery reaction system based on ultrafine catalyst

Abstract

This invention provides a catalyst recovery reaction system based on ultrafine catalysts. The catalyst recovery reaction system includes a reaction tower and a nano-micro catalyst separator connected in sequence. The reaction tower has a two-stage structure, comprising an upper coarse-diameter section and a lower fine-diameter section. An intensifier unit is installed at the bottom of the fine-diameter section, and multiple layers of grids are installed within the coarse-diameter section. This invention significantly improves catalytic reaction efficiency and catalyst recovery rate through the synergistic effect of multiple layers of grids, the intensifier unit, and high-efficiency separation technology. Simultaneously, the two-stage structure of the reaction tower, combining a catalyst-repellent coating and a dynamic anti-fouling ultrafiltration membrane, effectively prevents catalyst deposition and membrane fouling, ensuring efficient and stable operation of the reaction process.

Description

Technical Field

[0001] This utility model belongs to the field of chemical production technology, specifically to a recovery reaction system based on an ultrafine catalyst. Background Technology

[0002] In the field of chemical production, the development of efficient catalytic reaction systems has always been a key focus of technological research, especially when ultrafine catalysts are involved. The dispersibility, reaction efficiency, and recovery rate of the catalyst directly determine the economic efficiency and environmental friendliness of the entire process. Traditional catalytic reaction systems typically employ fixed-bed or fluidized-bed reactors, which, while achieving catalytic reactions to some extent, face numerous bottlenecks in the application of ultrafine catalysts. First, due to their extremely small particle size, ultrafine catalysts are prone to agglomeration or deposition during the reaction, leading to a reduction in active sites and a significant decrease in reaction efficiency. Second, traditional separation technologies struggle to efficiently recover ultrafine catalysts, resulting in resource waste and increased production costs. Furthermore, catalyst loss and contamination during the reaction process severely restrict the long-term stable operation of the system. While existing technologies attempt to optimize catalyst recovery by improving reactor structure or introducing novel separation equipment, they often fail to achieve ideal results due to unreasonable design or insufficient material performance. For example, some systems use ordinary filters to separate the catalyst, but due to the wide particle size distribution of ultrafine catalysts, the separation efficiency is low, and the filter membrane is easily fouled and clogged, requiring frequent replacements and increasing maintenance costs. Other technologies attempt to stabilize catalysts chemically, but this may introduce additional reagents, affecting product purity or increasing the difficulty of subsequent processing. Furthermore, traditional reaction systems are poor in terms of energy consumption, with significant heat loss during the reaction process, further exacerbating production costs and environmental burden.

[0003] To address these issues, there is an urgent need to develop a novel catalyst recovery reaction system that can effectively solve the problems of ultrafine catalyst dispersion, reaction efficiency, and recovery, while achieving low energy consumption and high stability operation.

[0004] In view of the above, this utility model is hereby proposed. Utility Model Content

[0005] The primary objective of this invention is to provide a recovery reaction system based on ultrafine catalysts. This system is suitable for reaction systems catalyzed by ultrafine catalysts. By designing a two-stage reaction tower structure and combining it with multi-layer grids and enhanced units, the system optimizes the hydrodynamic conditions of the reaction fluid, thereby improving the dispersion of the catalyst and the reaction efficiency. The nano-micro catalyst separator adopts a unique geometric design and a high-performance coating to achieve efficient separation and recycling of the catalyst. The application of a dynamic anti-fouling ultrafiltration membrane and a catalyst-repellent coating further reduces system pollution and energy consumption.

[0006] In order to achieve the above-mentioned objectives of this utility model, the following technical solution is adopted:

[0007] A recovery reaction system based on ultrafine catalysts includes a reaction tower and a nano-micro catalyst separator connected in sequence. The reaction tower has a two-section structure, which includes an upper coarse-diameter section and a lower fine-diameter section. An intensifying unit is provided at the bottom of the fine-diameter section, and a multi-layer grid is provided inside the coarse-diameter section. The inner diameter of the coarse-diameter section is 1.2-2 times the inner diameter of the fine-diameter section.

[0008] The nano-micro catalyst separator includes an upper cylindrical section and a lower conical section. The inner diameter of the cylindrical section is the same as the maximum inner diameter of the conical section, and the height of the cylindrical section is 2-2.5 times the height of the conical section. A filter assembly is provided at the top of the nano-micro catalyst separator, and a catalyst outlet is provided at the bottom of the nano-micro catalyst separator. The catalyst outlet is connected to a catalyst return pump. An outlet is provided on one side of the top of the nano-micro catalyst separator and is connected to a storage tank. An inlet is provided in the middle of the nano-micro catalyst separator and is connected to the reaction tower.

[0009] This invention provides a recovery reaction system based on an ultrafine catalyst. This system is suitable for reaction systems catalyzed by ultrafine catalysts, such as the reaction of formaldehyde and acetylene to produce BYD. The core of this invention lies in the synergistic design of a specific two-stage reaction tower and a nano-micro catalyst separator, which solves the technical problems of uneven catalyst dispersion, difficult recovery, and low reaction efficiency in traditional catalytic reaction systems. Furthermore, this ultrafine catalyst recovery reaction system, through its unique design, achieves efficient reaction completion under ultrafine catalyst conditions while simultaneously enabling catalyst recovery. The core of this system is the two-stage structure of the reaction tower, consisting of an upper coarse-diameter section and a lower fine-diameter section. The coarse-diameter section, serving as a catalyst pre-separation section, has an inner diameter 1.2-2 times that of the fine-diameter section. By increasing the flow cross-sectional area and reducing the fluid velocity, most of the ultrafine catalyst settles naturally under gravity, achieving preliminary separation. Simultaneously, multiple layers of grids are arranged within the coarse-diameter section. The grid surface is coated with a catalyst-repellent coating composed of polytetrafluoroethylene and nano-silica particles. This coating significantly reduces catalyst adhesion to the grid surface, further preventing catalyst rise and ensuring efficient catalyst retention during the reaction process. The multi-layered grid in the coarse-diameter section also prevents back-mixing of materials. The fine-diameter section, as the main reaction zone, features a bottom-mounted intensifier unit that uses high shear force to break the material into micro- and nano-sized bubbles, enhancing the contact efficiency between reactants and catalyst, resulting in a more complete reaction and significantly increasing the reaction rate. Furthermore, the height ratio of the upper cylindrical section to the lower conical section of the nano-catalyst separator ensures efficient sedimentation and collection of catalyst particles during separation. The filter assembly at the top of the nano-catalyst separator uses an ultrafiltration membrane structure combined with a dynamic anti-fouling coating, effectively preventing membrane fouling and extending service life. The catalyst outlet at the bottom is connected to a catalyst return pump, enabling continuous catalyst recycling and significantly reducing production costs.

[0010] Preferably, as a further feasible option, the surface of each layer of the multi-layer grid is coated with a catalyst-repellent coating, which is composed of polytetrafluoroethylene and nano-silica particles.

[0011] This invention further defines the catalyst recovery reaction system, specifically involving a catalyst-repellent coating technology on the surface of a multi-layer grid. This coating is composed of polytetrafluoroethylene (PTFE) and nano-silica particles. This design fundamentally solves the technical problem of catalyst adhesion and agglomeration on the grid surface in traditional catalytic reaction systems. In chemical production processes, especially in reaction systems involving ultrafine catalysts, catalyst particles, due to their extremely small size and high surface energy, are prone to deposition on the surface of reactor internals. This not only leads to the loss of active catalyst but also alters the fluid flow state, forming reaction dead zones and severely affecting reaction efficiency and product quality. Traditional solutions typically employ methods such as increasing flow rate or mechanical cleaning, but these methods are either too energy-intensive or... Frequent downtime for maintenance makes it difficult to meet the demands of continuous industrial production. Therefore, this invention constructs a catalyst-repellent coating on the surface of a multi-layer grid. By utilizing the low surface energy of PTFE and the synergistic effect of the microscopic rough structure of nano-silica particles, a super-repellent catalytic interface similar to the "lotus leaf effect" is formed on the material surface, making it difficult for catalyst particles to adhere. At the same time, it maintains the uniform distribution of fluid between the grids. The catalyst-repellent performance of this coating is not a simple physical barrier, but rather a composite surface with a specific topological structure formed at the microscale by precisely controlling the ratio and dispersion state of PTFE and nano-silica. Its surface free energy is controlled within an extremely low range, which significantly reduces the interaction energy between catalyst particles and the coating surface, making them easy to detach.

[0012] In addition, in this catalyst-repellent coating, PTFE, as a classic fluoropolymer, has extremely low surface energy and excellent chemical inertness, which can resist the erosion of various corrosive media in the reaction system and ensure the stability of the coating during long-term use. However, the mechanical strength of pure PTFE coating is insufficient, and it is easily worn under high-speed fluid scouring. Although its smooth surface can reduce adhesion, its repulsion effect on catalyst particles is limited. Therefore, this invention introduces nano-silica particles as a reinforcing phase. These particles are uniformly dispersed in the PTFE matrix. On the one hand, they improve the hardness and wear resistance of the coating through physical filling. On the other hand, they form a nanoscale protrusion structure on the coating surface, which greatly increases the surface roughness. This composite structure coating minimizes the actual contact area between the catalyst particles and the surface.

[0013] Preferably, as a further feasible option, the nano-silica particles have a particle size of 20-50 nm and are uniformly dispersed in polytetrafluoroethylene body, and the thickness of the catalyst coating is 10-30 μm.

[0014] This invention further specifies the technical details of the catalyst coating, specifically defining the particle size range of the nano-silica particles as 20-50 nm, requiring these nanoparticles to be uniformly dispersed in the polytetrafluoroethylene matrix, and clarifying that the coating thickness is controlled within the range of 10-30 μm. This allows the two to form a synergistic system solution, fundamentally solving the technical problems of catalyst agglomeration and deposition in traditional catalytic reactions. In reactions involving ultrafine catalysts, catalyst particles, due to their extremely high specific surface area and surface energy, are highly prone to agglomeration. This not only significantly reduces the effective utilization rate of catalytic active sites but also leads to non-selective deposition of the catalyst on the surface of reactor internals, subsequently causing a series of chain problems such as flow channel blockage and decreased mass transfer efficiency. Therefore, this invention... This novel method precisely controls the particle size of nano-silica particles within the range of 20-50 nm. This provides sufficient surface roughness to enhance the catalytic degradation effect without compromising the continuity and mechanical strength of the coating due to excessively large particle size. While particles smaller than 20 nm exhibit better dispersibility, they struggle to form effective surface micro / nano structures, resulting in poor catalytic degradation. Conversely, particles larger than 50 nm tend to form noticeable protrusions on the coating surface, affecting the uniformity of fluid flow and potentially causing coating damage under long-term scouring by high-speed fluids. Furthermore, the uniform dispersion of nano-silica particles within the PTFE matrix is ​​crucial for ensuring the stability of the coating performance. This uniform dispersion allows for the formation of evenly distributed micro / nano-scale protrusion structures on the coating surface, resulting in stable and durable catalytic degradation performance on a macroscopic scale.

[0015] Preferably, as a further feasible option, the inner wall of the nano-micro catalyst separator is coated with a wear-resistant and catalyst-repellent composite coating, which is composed of tungsten carbide particles and polyetheretherketone, and the thickness of the wear-resistant and catalyst-repellent composite coating is 50-150 μm.

[0016] Furthermore, the catalyst recovery reaction system of this invention also coats the inner wall of the nano-micro catalyst separator with a wear-resistant and catalyst-repellent composite coating. This coating consists of tungsten carbide particles and polyetheretherketone (PEEK), with a thickness controlled within the range of 50-150 μm. This solves two core problems faced by catalyst separators during long-term operation: firstly, the continuous wear of the inner wall by ultrafine catalyst particles; and secondly, the deposition and adhesion of catalyst on the inner wall surface. In chemical production practice, traditional separator inner walls are either made of ordinary metals or alloys, which, while possessing a certain degree of wear resistance, cannot prevent catalyst adhesion; or they are lined with plastic, which, while reducing adhesion, lacks sufficient wear resistance. Therefore, this invention combines high-hardness tungsten carbide particles with high-performance engineering plastic PEEK to form a novel coating material that combines excellent wear resistance and catalyst-repellent properties. Simultaneously, by precisely controlling the coating thickness within the specific range of 50-150 μm, the optimal balance between wear resistance and catalyst-repellent properties is achieved. Tungsten carbide, as an ultra-hard material second only to diamond in hardness, significantly enhances the coating's wear resistance through the introduction of its particles. PEEK, as a special engineering plastic, not only has excellent mechanical strength and chemical corrosion resistance, but also has certain low surface energy characteristics, providing a basic catalytic degradation function for the coating. The thickness range of the coating can ensure that the coating has sufficient mechanical strength to resist the long-term erosion and wear of catalyst particles, without causing excessive internal stress in the coating due to excessive thickness, which would affect adhesion or increase manufacturing costs. When the coating thickness is less than 50μm, its wear life is significantly shortened, and it is prone to local damage under the continuous erosion of high-speed catalyst-containing materials. When the thickness exceeds 150μm, it not only increases the material cost, but may also cause the coating to crack or peel off due to the difference in thermal expansion coefficient.

[0017] Preferably, as a further feasible option, the filtration component is an ultrafiltration membrane, the surface of which is coated with a dynamic antifouling coating, the dynamic antifouling coating being composed of zwitterionic polymers and nano-graphene.

[0018] This invention specifies that the filtration component in the catalyst recovery reaction system is an ultrafiltration membrane coated with a dynamic antifouling coating. This coating is composed of zwitterionic polymers and nano-graphene, solving the industry problem of easy fouling and rapid flux decline of ultrafiltration membranes during catalyst separation. In the field of chemical separation, ultrafiltration membrane fouling has always been a bottleneck restricting its large-scale industrial application, especially when dealing with complex systems containing ultrafine catalysts. Traditional ultrafiltration membranes often experience a sharp decline in flux within a short period of time due to catalyst particle deposition and organic matter adsorption, requiring frequent chemical cleaning or physical backwashing. This not only increases operating costs but also affects the continuity of production. This invention, by organically combining the antifouling properties of zwitterionic polymers with the enhanced mass transfer function of nano-graphene, has developed a dynamic antifouling coating with self-cleaning capabilities. By precisely controlling the synergistic effect of the two functional materials, a self-cleaning dynamic antifouling coating is achieved. The dynamic repulsion and removal of contaminants on the membrane surface is achieved through amphoteric polymers. Due to the presence of both positive and negative charged groups in their molecular structure, zwitterionic polymers can form a tight hydration layer in aqueous solutions, giving them excellent non-specific adsorption capabilities. The introduction of nano-graphene not only enhances the coating's mechanical strength and thermal conductivity, but its unique two-dimensional structure also provides additional mass transfer channels, significantly improving the membrane's permeation flux. The "dynamic" characteristic of the dynamic antifouling coating is reflected in its responsiveness to changes in the external environment. When contaminant deposition begins on the membrane surface, the conformation of the zwitterionic polymer molecular chains adjusts with the interfacial environment, repelling contaminants through enhanced hydration. Simultaneously, the presence of nano-graphene increases surface energy, making it more difficult for deposits to adhere firmly. This dynamic response mechanism allows the coating to adapt to catalyst suspensions of different compositions and properties, maintaining a long-lasting antifouling effect.

[0019] Preferably, as a further feasible option, the content of the nano-graphene is 0.5%-2% of the total mass of the coating.

[0020] This invention also limits the content of nano-graphene in the dynamic antifouling coating to 0.5%-2% of the total coating mass. When the nano-graphene content is below 0.5%, its dispersed network in the coating is difficult to form effectively, limiting its improvement on the mechanical strength and mass transfer performance of the membrane material, and failing to fully utilize the unique two-dimensional structural advantages and excellent thermal conductivity of nano-graphene. While when the content exceeds 2%, although the mechanical properties of the coating are further enhanced, excessive nano-graphene will partially cover the hydrophilic groups of the zwitterionic polymer, weakening its hydration ability. Simultaneously, the π-π stacking effect between nanosheets is enhanced, easily forming local agglomerations, which not only reduces the uniformity of the coating but may also block some membrane pores, affecting the separation flux. Within the 0.5%-2% range, nano-graphene can be uniformly dispersed in the zwitterionic polymer matrix, thus forming a... This method effectively enhances the network without compromising the antifouling properties of the matrix polymer, achieving a perfect balance between mechanical properties and surface functionality. Furthermore, due to its moderate content, the nano-graphene sheets are fully encapsulated and isolated by zwitterionic polymer molecules, preventing direct contact and aggregation between graphene sheets and maintaining good dispersion stability. Simultaneously, these uniformly dispersed nano-graphene sheets and zwitterionic polymer molecular chains form stable interfacial bonds through electrostatic interactions, hydrogen bonds, and other forces, constructing an organic-inorganic hybrid three-dimensional network structure. This structure not only possesses excellent mechanical properties, but more importantly, the oxygen-containing functional groups remaining at the edges and surface of the nano-graphene interact strongly with the charged groups of the zwitterionic polymer, enabling the entire coating system to maintain structural integrity under external stress or solvent erosion.

[0021] Preferably, as a further feasible option, a first feed inlet, a second feed inlet, a buffer solution feed inlet, and a catalyst feed inlet are respectively provided on one side of the bottom of the reaction tower. The first feed inlet and the second feed inlet are connected to the intensifier unit. A filter is provided on the second feed inlet. A circulation feed inlet is provided on the other side of the reaction tower and is connected to the catalyst return pump. A reaction liquid outlet is also provided at the top of the reaction tower and is connected to the feed inlets.

[0022] Preferably, as a further feasible option, a circulating liquid outlet is provided below the reaction liquid outlet, the circulating liquid outlet is connected to a circulating pump, the circulating pump is connected to an intensifier unit, and a heat exchanger is also provided between the circulating pump and the circulating liquid outlet.

[0023] The specific reaction process of the system of this utility model is as follows:

[0024] When the reaction system is started, the reaction raw materials are injected into the system through the first feed port set at the bottom of the reaction tower. At the same time, other reaction raw materials are purified by a filter to remove any possible impurities such as sulfides and moisture before entering the system through the second feed port. The buffer solution is added through a separate buffer solution feed port to maintain the optimal pH conditions of the reaction system. The ultrafine catalyst suspension is injected through the catalyst feed port. All raw materials are broken into microbubbles in the intensifier unit at the bottom of the fine section, thereby increasing the contact area between the reaction raw materials and improving the reaction efficiency. During this process, the reaction temperature is returned to the reaction system after heat exchange through an external circulating pump and heat exchanger.

[0025] The reacted mixture then flows upward into the coarse-diameter section of the reaction tower. Since the inner diameter of the coarse-diameter section is 1.2-2 times that of the fine-diameter section, the flow rate suddenly decreases, causing most of the catalyst particles to begin to settle under gravity. At the same time, the vertically arranged multi-layer grids in the coarse-diameter section further prevent the catalyst from rising and the material from back-mixing. Each grid layer is coated with a 10-30μm thick catalyst-repellent coating, which consists of polytetrafluoroethylene and silica particles with a particle size of 20-50nm, reducing the amount of catalyst adhering by more than 90%.

[0026] A small amount of catalyst that failed to settle flowed out of the reaction liquid outlet at the top of the reaction tower along with the reaction liquid. It then entered the nano-catalyst separator tangentially through the feed inlet on the nano-catalyst separator. Due to the unique combination of cylindrical and conical sections in the separator, the reaction liquid mixed with catalyst particles generated a vortex as it entered the conical section at the bottom of the separator tangentially. This caused the catalyst to be thrown out under centrifugal force, thus achieving catalyst separation. The catalyst was then thrown against the inner wall of the conical section of the separator. The thick wear-resistant and catalyst-repellent composite coating on the inner wall of the separator reduces the adhesion of the catalyst to the inner wall of the nano-micro catalyst separator, so that the catalyst particles gradually settle to the bottom of the conical section, while a small amount of unsettled catalyst flows upward and settles through the top filter assembly. The filter assembly uses an ultrafiltration membrane with a dynamic antifouling coating on the membrane surface. This coating is composed of zwitterionic polymer and graphene oxide. Finally, the pure product solution enters the storage tank from the top outlet of the nano-micro catalyst separator, while the catalyst settled at the bottom of the nano-micro catalyst separator is recycled back to the reaction tower by the catalyst return pump.

[0027] The top of the reaction tower is also equipped with a circulating liquid outlet, in which part of the reactants are extracted by a circulating pump, heat exchanged by a heat exchanger, and then reintroduced into the reaction tower to achieve heat replacement.

[0028] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0029] (1) This utility model proposes a recovery reaction system based on ultrafine catalyst. By designing a two-stage reaction tower structure and combining it with multi-layer grid and enhanced unit, the reaction fluid dynamics conditions are optimized, thereby improving the dispersion and reaction efficiency of the catalyst. The nano-micro catalyst separator adopts a unique geometric design and high-performance coating to achieve efficient separation and recycling of the catalyst. The application of dynamic anti-fouling ultrafiltration membrane and catalyst-repellent coating further reduces system pollution and energy consumption. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0031] Figure 1 This is a structural diagram of a recovery reaction system based on an ultrafine catalyst according to the present invention;

[0032] Figure 2 This is a schematic diagram of the feeding method of the reactants in the nano-micro catalyst separator of a recovery reaction system based on ultrafine catalysts according to this utility model.

[0033] In the attached diagram:

[0034] 1. Reaction tower; 2. Grille; 3. First feed inlet; 4. Acetylene inlet; 5. Filter; 6. Circulation pump; 7. Catalyst return pump; 8. Heat exchanger; 9. Nano-micro catalyst separator; 10. Storage tank; 11. Buffer feed inlet; 12. Catalyst feed inlet; 13. Enhancement unit; 14. Filter assembly; 15. Feed inlet. Detailed Implementation

[0035] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this utility model, not all embodiments, and are only used to illustrate this utility model, and should not be regarded as limiting the scope of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0036] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0038] To more clearly illustrate the technical solution of this utility model, the following description is provided in the form of specific embodiments.

[0039] Example 1

[0040] This embodiment describes in detail the application of the recovery reaction system based on an ultrafine catalyst in the reaction system for preparing BYD based on an ultrafine catalyst. The complete operation process is as follows:

[0041] Please see Figure 1 When the reaction system is started, the first feed is injected into the first inlet 3 at the bottom of the reaction tower 1 at a constant flow rate of 10 L / min. At the same time, the second feed is injected into the first inlet 4 at a constant flow rate of 5 m after passing through the filter 5 to remove impurities such as sulfides and moisture. 3 A flow rate of 2 L / min is introduced into the system. To maintain the optimal pH environment of the reaction system, buffer solution is added through buffer inlet 11 at a flow rate of 2 L / min. The suspension of ultrafine catalyst is injected into the system through catalyst inlet 12 at a flow rate of 1.5 L / min. Subsequently, all raw materials are fully mixed in the intensifier unit at the bottom of the fine diameter section to improve the reaction efficiency. At the same time, the intensifier unit breaks the reactants into microbubbles, thereby increasing the contact area between the reactants and improving the reaction efficiency. Meanwhile, the reaction temperature is replaced by an externally connected circulating pump 6 and heat exchanger 8, thereby reducing the temperature inside the reaction tower.

[0042] After the reaction, the mixture flows upward into a coarse-diameter section with an inner diameter 1.2 times that of the fine-diameter section. Due to the sudden increase in the flow cross-sectional area, the fluid linear velocity decreases significantly. At this point, the catalyst particles begin to settle at the bottom of the reaction tower under gravity. The three vertically installed grids 2 in the coarse-diameter section further enhance the catalyst retention effect. Each grid is 200 mm apart and coated with a 10 μm thick catalyst-repellent coating (composed of 85 wt% polytetrafluoroethylene and 15 wt% silica particles with a particle size of 20 nm). This coating reduces the amount of catalyst adhering to the grid surface. The portion of ultrafine catalyst that fails to settle flows out of the reaction liquid outlet at the top of the reaction tower with the reaction liquid and then enters the nano-micro catalyst separator 9 tangentially through the feed inlet 15 in the middle of the nano-micro catalyst separator 9. The specific feed direction is as follows: Figure 2 As shown;

[0043] Inside the nano-micro catalyst separator, the mixture enters the conical section at the bottom of the separator tangentially. The conical section generates a vortex, thereby using centrifugal force to separate the catalyst. Under these conditions, the catalyst particles are thrown against the inner wall of the conical section. At the same time, the inner wall of the nano-micro catalyst separator is coated with a 50 μm thick wear-resistant and catalyst-repellent composite coating (composed of 60 wt% tungsten carbide particles with a particle size of 5 μm and 40 wt% polyetheretherketone). This coating effectively prevents particle adhesion.

[0044] At this point, most of the catalyst settles to the bottom of the conical section. The settled catalyst is then circulated back to the reaction tower 1 via the catalyst return pump 7. The remaining ultrafine catalyst rises with the liquid phase to a cylindrical section at the top of the nano-micro catalyst separator, which is twice the height of the conical section. Subsequently, it passes through an ultrafiltration membrane assembly installed at the top of the cylindrical section of the nano-micro catalyst separator, thus achieving catalyst separation and sedimentation. The surface of this ultrafiltration membrane is coated with a dynamic antifouling coating (composed of zwitterionic polymer and 0.5 wt% graphene oxide). This coating reduces the rate of contaminant deposition. Finally, the pure BYD solution enters the storage tank 10 from the top outlet of the nano-micro catalyst separator to await subsequent distillation and purification. At the same time, the circulating liquid outlet at the top of the reaction tower 1 uses a circulating pump 6 to pump 20% of the reaction liquid through a heat exchanger 8 and then reinject it into the bottom of the reaction tower, thereby achieving heat exchange.

[0045] Example 2

[0046] This embodiment describes in detail the application of the recovery reaction system based on an ultrafine catalyst in the reaction system for preparing BYD based on an ultrafine catalyst. The complete operation process is as follows:

[0047] Please see Figure 1When the reaction system is started, a first feed with a mass concentration of 37% is first injected through the first feed inlet 3 at the bottom of the reaction tower 1 at a constant flow rate of 10 L / min. At the same time, a second feed with high purity (purity ≥99.9%) is injected through the second feed inlet 4 at a constant flow rate of 10 L / min after passing through the filter 5 to remove impurities such as sulfides and moisture. 3 A flow rate of 2 L / min is introduced into the system. To maintain the optimal pH environment of the reaction system, buffer solution is added through buffer inlet 11 at a flow rate of 2 L / min. The suspension of ultrafine catalyst is injected into the system through catalyst inlet 12 at a flow rate of 1.5 L / min. Subsequently, all raw materials are fully mixed in the intensifier unit at the bottom of the fine diameter section to improve the reaction efficiency. At the same time, the intensifier unit breaks the reactants into microbubbles, thereby increasing the contact area between the reactants and improving the reaction efficiency. Meanwhile, the reaction temperature is replaced by an externally connected circulating pump 6 and heat exchanger 8, thereby reducing the temperature inside the reaction tower.

[0048] After the reaction, the mixture flows upward into the coarse-diameter section, which has an inner diameter twice that of the fine-diameter section. Due to the sudden increase in the flow cross-sectional area, the fluid linear velocity decreases significantly. At this point, the catalyst particles begin to settle at the bottom of the reaction tower under gravity. The seven vertically installed grids 2 in the coarse-diameter section further enhance the catalyst retention effect. Each grid is spaced 200 mm apart and coated with a 30 μm thick catalyst-repellent coating (composed of 85 wt% polytetrafluoroethylene and 15 wt% silica particles with a particle size of 50 nm). This coating reduces the amount of catalyst adhering to the grid surface. The portion of ultrafine catalyst that fails to settle flows out of the reaction liquid outlet at the top of the reaction tower with the reaction liquid and then enters the nano-micro catalyst separator 9 tangentially through the feed inlet 15 in the middle of the nano-micro catalyst separator 9. The specific feed direction is as follows: Figure 2 As shown;

[0049] Inside the nano-micro catalyst separator, the mixture enters the conical section at the bottom of the separator tangentially. A stable swirling field is formed by the vortex generator in the conical section, generating centrifugal force. Under these conditions, the catalyst particles are thrown towards the inner wall of the conical section. At the same time, the inner wall of the nano-micro catalyst separator is coated with a 150 μm thick wear-resistant and catalyst-repellent composite coating (composed of 60 wt% tungsten carbide particles with a particle size of 5 μm and 40 wt% polyetheretherketone). This coating effectively prevents particle adhesion.

[0050] At this point, most of the catalyst settles to the bottom of the conical section. The settled catalyst is then circulated back to the reaction tower 1 via the catalyst return pump 7. The remaining ultrafine catalyst rises with the liquid phase to the cylindrical section at the top of the nano-micro catalyst separator, which is 2.5 times the height of the conical section. Subsequently, it passes through an ultrafiltration membrane assembly at the top of the cylindrical section to achieve catalyst separation. The surface of this ultrafiltration membrane is coated with a dynamic antifouling coating (composed of zwitterionic polymer and 2wt% graphene oxide). This coating reduces the rate of contaminant deposition. Finally, the pure BYD solution enters the storage tank 10 from the top outlet of the nano-micro catalyst separator to await subsequent distillation and purification. At the same time, the circulating liquid outlet at the top of the reaction tower 1 uses the circulating pump 6 to pump 20% of the reaction liquid through the heat exchanger 8 and then reinject it into the bottom of the reaction tower, thereby achieving heat exchange.

[0051] Example 3

[0052] This embodiment describes in detail the application of the recovery reaction system based on an ultrafine catalyst in the reaction system for preparing BYD based on an ultrafine catalyst. The complete operation process is as follows:

[0053] Please see Figure 1 When the reaction system is started, a first feed with a mass concentration of 37% is first injected through the first feed inlet 3 at the bottom of the reaction tower 1 at a constant flow rate of 10 L / min. At the same time, a second feed with high purity (purity ≥99.9%) is injected through the second feed inlet 4 at a constant flow rate of 10 L / min after passing through the filter 5 to remove impurities such as sulfides and moisture. 3 A flow rate of 2 L / min is introduced into the system. To maintain the optimal pH environment of the reaction system, buffer solution is added through buffer inlet 11 at a flow rate of 2 L / min. The suspension of ultrafine catalyst is injected into the system through catalyst inlet 12 at a flow rate of 1.5 L / min. Subsequently, all raw materials are fully mixed in the intensifier unit at the bottom of the fine diameter section to improve the reaction efficiency. At the same time, the intensifier unit breaks the reactants into microbubbles, thereby increasing the contact area between the reactants and improving the reaction efficiency. Meanwhile, the reaction temperature is replaced by an externally connected circulating pump 6 and heat exchanger 8, thereby reducing the temperature inside the reaction tower.

[0054] After the reaction, the mixture flows upward into the coarse-diameter section, which has an inner diameter 1.6 times that of the narrow section. Due to the sudden increase in the flow cross-sectional area, the fluid linear velocity decreases significantly. At this point, the catalyst particles begin to settle at the bottom of the reaction tower under gravity. The five vertically installed grids 2 in the coarse-diameter section further enhance the catalyst retention effect. Each grid has a spacing of 200 mm and is coated with a 20 μm thick catalyst-repellent coating (composed of 85 wt% polytetrafluoroethylene and 15 wt% silica particles with a particle size of 35 nm). This coating reduces the amount of catalyst adhering to the grid surface. The portion of ultrafine catalyst that fails to settle flows out of the reaction liquid outlet at the top of the reaction tower and then tangentially enters the nano-micro catalyst separator 9 through the feed inlet 15 in the middle of the nano-micro catalyst separator 9. The specific feed direction is as follows: Figure 2 As shown;

[0055] Inside the nano-micro catalyst separator, the mixture enters the conical section at the bottom of the separator tangentially. A stable swirling field is formed by the vortex generator in the conical section, generating centrifugal force. Under these conditions, the catalyst particles are thrown towards the inner wall of the conical section. At the same time, the inner wall of the nano-micro catalyst separator is coated with a 100 μm thick wear-resistant and catalyst-repellent composite coating (composed of 60 wt% tungsten carbide particles with a particle size of 5 μm and 40 wt% polyetheretherketone). This coating effectively prevents particle adhesion.

[0056] At this point, most of the catalyst settles to the bottom of the conical section. The settled catalyst is then circulated back to the reaction tower 1 via the catalyst return pump 7. The remaining ultrafine catalyst rises with the liquid phase to the cylindrical section at the top of the nano-micro catalyst separator, which is 2.2 times the height of the conical section. The catalyst is then separated by an ultrafiltration membrane assembly located at the top of the cylindrical section. The surface of the ultrafiltration membrane is coated with a dynamic antifouling coating (composed of zwitterionic polymer and 1 wt% graphene oxide). This coating reduces the deposition rate of contaminants. Finally, the pure BYD solution enters the storage tank 10 from the top outlet of the nano-micro catalyst separator to await subsequent distillation and purification. Meanwhile, the circulating liquid outlet at the top of the reaction tower 1 uses the circulating pump 6 to pump 20% of the reaction liquid through the heat exchanger 8 and then reinject it into the bottom of the reaction tower, thereby achieving heat exchange.

[0057] Experimental Example 1: Performance Verification of the Catalyst Recovery Reaction System for the Preparation of BYD from Ultrafine Catalysts

[0058] 1. Experimental objective: To verify the performance advantages of the ultrafine catalyst-based recovery reaction system of this invention in terms of catalyst dispersion, reaction efficiency, catalyst recovery rate and membrane fouling control in ultrafine catalyst-based reaction systems, and to compare it with traditional catalyst recovery reaction systems;

[0059] 2. Experimental Methods

[0060] Experimental group: The catalyst recovery reaction system described in Examples 1-3 of this utility model was used;

[0061] Control group: Comparative example 1 used a traditional BYD reaction system;

[0062] Test indicators: catalyst recovery rate, BYD space-time yield, membrane fouling cycle, energy consumption, and catalyst activity loss rate. The final test results are shown in Table 1 below.

[0063] Table 1 Test Results

[0064]

[0065] The recovery reaction system based on ultrafine catalyst provided by this invention, through detailed implementation of Examples 1-3 and comparative testing with Comparative Example 1, comprehensively verified its significant advantages in catalyst dispersibility, reaction efficiency, recovery rate, and system stability. Examples 1-3, through a two-stage reaction tower structure, the synergistic effect of functional coatings, and an optimized nano-micro catalyst separator design, achieved highly efficient catalyst utilization and recovery. In contrast, traditional systems, due to structural defects and insufficient material performance, lagged significantly behind in many indicators. Specifically, the core of this invention lies in promoting catalyst sedimentation through a two-stage reaction tower, reducing catalyst adhesion by more than 90% with a multi-layer grid catalyst-repellent coating, solving wear and adhesion problems with the wear-resistant and catalyst-repellent composite coating of the nano-micro separator, and extending the fouling cycle to 6-9 times that of traditional systems with a dynamic anti-fouling ultrafiltration membrane. Experimental data show that the catalyst recovery rate, space-time yield, and energy consumption of Examples 1-3 are significantly better than those of Comparative Example 1, especially Example 3, which achieves the lowest energy consumption while maintaining a high recovery rate.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model 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 this utility model.

Claims

1. A recovery reaction system based on an ultrafine catalyst, characterized in that, The device includes a reaction tower and a nano-micro catalyst separator connected in sequence. The reaction tower has a two-section structure, which includes an upper coarse-diameter section and a lower fine-diameter section. An intensifying unit is installed at the bottom of the fine-diameter section, and a multi-layer grid is installed inside the coarse-diameter section. The inner diameter of the coarse-diameter section is 1.2-2 times that of the inner diameter of the fine-diameter section. The nano-micro catalyst separator includes an upper cylindrical section and a lower conical section. The inner diameter of the cylindrical section is the same as the maximum inner diameter of the conical section, and the height of the cylindrical section is 2-2.5 times the height of the conical section. A filter assembly is provided at the top of the nano-micro catalyst separator, and a catalyst outlet is provided at the bottom of the nano-micro catalyst separator. The catalyst outlet is connected to a catalyst return pump. An outlet is provided on one side of the top of the nano-micro catalyst separator and is connected to a storage tank. An inlet is also provided on the nano-micro catalyst separator and is connected to the reaction tower.

2. The recovery reaction system according to claim 1, characterized in that, Each layer of the multi-layer grid is coated with a catalyst-repellent coating, which is composed of polytetrafluoroethylene and nano-silica particles.

3. The recovery reaction system according to claim 2, characterized in that, The nano-silica particles have a particle size of 20-50 nm and are uniformly dispersed in polytetrafluoroethylene body, and the thickness of the catalyst coating is 10-30 μm.

4. The recovery reaction system according to claim 1, characterized in that, The inner wall of the nano-micro catalyst separator is coated with a wear-resistant and catalyst-repellent composite coating, which is composed of tungsten carbide particles and polyetheretherketone, and the thickness of the wear-resistant and catalyst-repellent composite coating is 50-150 μm.

5. The recovery reaction system according to claim 1, characterized in that, The filtration component is an ultrafiltration membrane, and the surface of the ultrafiltration membrane is coated with a dynamic antifouling coating, which is composed of zwitterionic polymer and nano-graphene.

6. The recovery reaction system according to claim 5, characterized in that, The content of the nano-graphene is 0.5%-2% of the total mass of the coating.

7. The recovery reaction system according to claim 1, characterized in that, The bottom of the reaction tower is provided with a first feed inlet, a second feed inlet, a buffer solution feed inlet, and a catalyst feed inlet. The first feed inlet and the second feed inlet are connected to the intensifier unit. A filter is provided on the second feed inlet. A circulation feed inlet is provided on the other side of the reaction tower and is connected to the catalyst return pump. A reaction liquid outlet is also provided at the top of the reaction tower and is connected to the feed inlets.

8. The recovery reaction system according to claim 7, characterized in that, A circulating liquid outlet is provided below the reaction liquid outlet. The circulating liquid outlet is connected to a circulating pump, which is connected to an intensifier unit. A heat exchanger is also provided between the circulating pump and the circulating liquid outlet.

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