Structured packing for high gravity rotating bed used for liquid-liquid precipitation reaction

Abstract

The present invention discloses a structured packing for a high-gravity rotating bed for liquid-liquid precipitation reaction, comprising a dispersion structure, a mixing structure, and a support structure; the support structure is composed of a plurality of concentric support rings and a detachable annular plate, and is arranged in parallel up and down, and a dispersion structure and a mixing structure consisting of an arc-shaped blade structure are provided between two layers of concentric rings; from the inside to the outside, the odd-numbered layers are the dispersion structure, and the arc-shaped blades of the dispersion structure are provided with circular holes with larger apertures; the even-numbered layers are the mixing structure, and the arc-shaped blades of the mixing structure are provided with circular holes with smaller apertures; gradually larger arc-shaped blades are provided in the interval annular layers and are arranged in a circle around the annular layers; the packing as a whole presents a plurality of "Z"-shaped dense multi-annular structures. The structured packing designed by the present invention can efficiently realize the full dispersion, aggregation and mixing of the liquid-liquid two-phase, and has many advantages such as large specific surface area, high mass transfer efficiency, high void ratio, easy installation and maintenance, no dead angle, and no material accumulation.

Description

Technical Field

[0001] The invention relates to a structured filler for a high-gravity rotating bed used for liquid-liquid precipitation reaction, belonging to the technical field of chemical equipment and process intensification. Background Art

[0002] Currently, one of the most far-reaching trends in the chemical industry is process intensification. As a new process intensification technology, high-gravity technology is an applied technology created using the scientific principles of high-gravity and has broad application prospects in industry. Among the many industrial reactions, liquid-liquid mixing and contact reactions currently account for the majority of reaction processes. Therefore, from the perspective of enhancing the transfer process and micromixing, the impinging stream-rotating packed bed coupling mechanism came into being. It effectively combines the advantages of both the impinging stream reactor and the rotating packed bed reactor, enabling the two-phase liquid to achieve contact and mass transfer under conditions of high dispersion, high turbulence, strong mixing, and rapid interface renewal. It has the characteristics of efficient micromixing, short residence time, small footprint, and easy installation and maintenance, making it more suitable for large-scale industrial production.

[0003] As the core component of the impinging stream-rotating packed bed, the packing plays an important role in the mass transfer and mixing inside it. The packing structure and characteristics determine the overall performance of the rotating packed bed. In order to further develop the application potential of the equipment, research and innovation on the equipment structure is very necessary. According to the packing method of the packing in the rotating bed, the packing can be divided into bulk packing and structured packing. Bulk packing was reported earlier and has been studied more. In 2021, Wang et al. ( Chemical Engineering Science.2021, 240 (1)) studied the impact of droplets on a rotating single-layer stainless steel wire mesh using high-speed camera technology and conducted three-dimensional numerical simulations, confirming that the increase in the impact angle increases the dispersion cone angle and reduces the average diameter of the droplets, which is beneficial to the dispersion of the liquid. Although the wire mesh filler has a large specific surface area and high mass transfer efficiency, from another perspective, the wire mesh filler will be deformed by the centrifugal force generated by the high-speed rotating rotor in the hypergravity field, breaking its geometric symmetry and dynamic balance, resulting in insufficient reaction mixing or uneven dispersion. In 2022, Wang Dan et al. (Journal of the Chinese Rare Earth Society. 2022, 40 (4): 616-623) used Pall ring fillers in an impinging stream-rotating packed bed to prepare 68 nm spherical nano-cerium oxide by precipitation reaction. From the SEM, it can be seen that the powder particles are small in size and evenly distributed, so the advantages of the hypergravity reactor are obvious. However, the density and filling degree of the ball ring packing structure will also lead to uneven reactions. When it is too dense, it is easy to clog and increase energy consumption; when it is too sparse, the mixing and reaction will be insufficient, and the packing will be more likely to deform. Structured packing has good uniformity and symmetry, and can still achieve mixing and dispersion of liquid-liquid phases in a high-speed rotating packed bed. Therefore, the development and design of new structured packing is very important for improving the performance of rotating packed beds. The surface modification of the packing, the packing structure, the manufacturing technology, and the installation method will affect the mass transfer and fluid mechanics properties of the packing. Among them, the packing structure has the most obvious effect on the mass transfer and fluid mechanics properties of the rotating bed. The purpose of improving the performance of the supergravity device can be achieved by changing the structure of the packing. In 2022, Zhang et al. (Chemical Engineering Journal. 2022, 427: 130874) conducted CFD simulations on a rotating packed bed reactor with wire mesh packing to understand the liquid flow in the packing area, such as Figure 1 As shown in the figure, at the packing inlet, the droplets move radially and are relatively dense. As the collision resistance increases while passing through the packing, the radial velocity decreases. As the droplets move away from the inlet, the radial velocity is very small due to the momentum loss during the initial impact at the inlet, and the droplets are basically dispersed.

[0004] In summary, designing a structured packing with appropriate density and non-clogging properties and applying it to liquid-liquid precipitation reactions has extremely important practical value. Summary of the Invention

[0005] To address the problems of uneven dispersion of packing channels, imprecise structure, easy reaction blockage, and inconvenient installation and maintenance within the impinging flow-rotating packed bed, the present invention provides a structured packing for a 3D-printed high-gravity rotating bed suitable for liquid-liquid precipitation reactions. The present invention utilizes Maxon Cinema 4D software to design a packing model and converts it into a solid packing using a 3D printer. In this packing, droplets generated by the collision of the two-phase liquid are evenly sprayed onto the inner edge of the packing layer. The strong shear force generated by the high-speed rotation of the packing driven by the motor further shears and disperses the droplets into liquid microelements, which are then fully mixed in the gaps between the packings, achieving multiple dispersion and aggregation of the materials, thereby significantly improving the mixing efficiency and reaction rate.

[0006] The structured packing for a high-gravity rotating packed bed suitable for liquid-liquid precipitation reactions provided by the present invention has an overall design that focuses on the aggregation and dispersion of two liquid phases inside. The structured packing model is designed using Maxon Cinema 4D three-dimensional modeling software, and a specific liquid phase reaction channel and a unique curved blade structure are constructed within the packing.

[0007] The present invention provides a structured packing for a high-gravity rotating bed for liquid-liquid precipitation reaction, comprising a dispersion structure, a mixing structure, and a support structure;

[0008] The support structure is composed of a plurality of concentric support rings and detachable annular plates, and is arranged in parallel up and down. A dispersed structure and a mixed structure composed of arc-shaped blade structures are provided between the two layers of concentric rings. The innermost and outermost layers of the rings are both dispersed structures, and are arranged from the inside to the outside as follows: the multi-layer support ring structure has a total of 2n layers (n≥2 and is a positive integer), wherein the odd-numbered layers, i.e., the 1st layer and the (2n-1)th layer, are dispersed structures, and the arc-shaped blades of the dispersed structure are provided with circular holes with larger apertures; the even-numbered layers (i.e., the 2nth layer) are mixed structures, and the arc-shaped blades of the mixed structure are provided with circular holes with smaller apertures; gradually larger arc-shaped blades are provided in the interval annular layers and are arranged in a circle around the annular layers, i.e., the sizes of the arc-shaped blades in the dispersed structure and the mixed structure increase as the circle in which they are located increases, and the overall size of the arc-shaped blades tends to gradually increase from the inside to the outside.

[0009] Liquid droplets passing through the dispersion and mixing structures pass through multiple curved blades, each uniformly provided with a number of circular holes of uniform aperture. Vertically adjacent circular holes on the blades are staggered at 45 degrees, and their apertures gradually decrease and their number increases from the inside out. The curved blades of the dispersion and mixing structures are fixed to supporting circular rings on both sides. Specifically, one vertical edge of the curved blades of the two structures is connected to the inner circular ring, and the other vertical edge is connected to the outer circular ring. Furthermore, one vertical edge of the curved blade of the dispersion structure intersects with a vertical edge of the curved blade of the adjacent mixing structure, ultimately forming a "Z"-shaped structure. Finally, a removable circular plate structure is used to secure the support structures of the upper and lower layers of the packing. A three-dimensional packing model with an overall "Z"-shaped multi-layer structure can be obtained from top view. This model has multiple components that facilitate segmentation and mixing, effectively achieving the aggregation and dispersion of droplets and reducing material retention. 3D printing technology was ultimately used to print the solid packing.

[0010] Specifically, the inner and outer diameters of the adjacent concentric rings are increased by 1.1 to 1.5 times. The innermost ring has an outer diameter (D) of 40 to 400 mm and a thickness of 1 to 2 mm. If the rotating packed bed is larger, the ring diameter can be further increased. On this basis, the adjacent outer diameters of the rings are enlarged by (1.1 to 1.5) × D to create a multi-layered ring structure. The distance between the upper and lower rings is H = 40 to 300 mm (this size can be adjusted according to actual conditions). To enhance the dispersion effect, a multi-layered arc-shaped blade structure is installed between the two rings, with a circle of arc-shaped blades between each adjacent ring.

[0011] The present invention provides a structured packing structure for a high-gravity rotating packed bed for liquid-liquid precipitation reactions, printed in one piece using 3D printing technology. The structure of the curved blades is described as follows: the central angle of the blades ranges from 15° to 45°. The blades are evenly distributed with circular holes, each with a size d of 2 to 6 mm, and are staggered d / 2 between the upper and lower layers. The spacing between the holes is approximately d / 2 to 2d, and the porosity is 60% to 70%. Too dense a distribution of holes will reduce the space for liquid flow, and a 1-5 mm space around the blades is required to allow them to fit within the rings. The curved blades are placed within two adjacent layers of supporting rings, with one end connected to the outer ring and the other to the inner ring. Furthermore, the curved blades in the dispersion structure rotate in the opposite direction to the reactor motor, allowing reactants to pass through them in a staggered manner. The curved blades in the mixing structure rotate in the opposite direction to the former, following the direction of motor rotation. If the direction of the arc-shaped blades in the dispersion structure is the same as the rotation direction of the motor, the reactants and products will be mixed first, thereby affecting the dispersion effect of the reactants.

[0012] The arcuate blade structure is placed within each layer of circular rings, with the spacing between adjacent layers of rings ≥5 mm. Concentric rings embed and secure 1-2 mm thick arcuate blades. From the inside out, the curvature and length of the blades change with increasing radius across all layers. In a dispersed structure, the angle between the blades in odd-numbered layers of rings and the inner ring of the ring layer is 35°-40°, followed by 15°-20° and 5°-10°. The angle decreases toward the outermost layer, and the appropriate number of ring layers and blades can be selected based on the actual packing size. In a mixed structure, the angle increases between even-numbered layers of rings and toward the outermost layers.

[0013] For the determination of the number of arc-shaped blades, both the dispersed structure and the mixed structure are consistent. The circumference of the ring is set to C. Since the ring is closed, the number of arc-shaped blades is set to m. Since the ring size needs to be selected according to the actual equipment, the interval d of the arc-shaped blades in the same ring is: d=C / m.

[0014] The number, size, and arrangement of the circular holes within the arcuate blades vary from the inner to the outer layers of the packing. This shift in orientation creates a multi-dimensional "Z"-shaped structure. Furthermore, as the radius of the ring increases, the number of holes increases and the radius decreases, facilitating multiple dispersion and aggregation of the product and unreacted raw materials, ensuring thorough mixing and complete reaction.

[0015] The multi-ring structure and the curved blade structure are relatively weak, so 1-6 mm thick removable ring plates are embedded on the upper and lower sides of the rings to support and fix the filler. The ring plates are located between the two supporting rings.

[0016] The method for constructing the structured packing structure is as follows: First, the structured packing model is designed using Maxon Cinema 4D 3D modeling software. Using a circular ring structure as the foundation, multiple circular ring structures are arranged along a radius around the same center, creating a multi-ring structure. Curved blade structures are embedded within the rings at a predetermined angle. Furthermore, removable circular plates are added above and below the rings to secure the packing, completing the packing structure. The solid packing is then printed using 3D printing technology, and the structured packing model is designed using Maxon Cinema 4D software. The software's design freedom allows the design of the dispersed, mixed, and support structures required for the 3D packing model.

[0017] Furthermore, Maxon Cinema 4D software was used to construct arc-shaped blades of a certain height with regularly arranged circular holes. These blades were arranged in a rotational pattern along and spaced apart from the circular ring. On the one hand, the circular ring with blades intersected with the droplets sprayed from the nozzle, achieving multiple dispersions of the liquid raw materials and products. On the other hand, the blades in the opposite direction thoroughly mixed the unreacted liquid raw materials, achieving multiple coalescence of the reactants. Finally, removable circular plates were embedded on the upper and lower surfaces of the packing to stabilize the packing and to deposit the back-splashed material into the packing. This structured packing was used in an impinging stream-rotating packed bed. The placement of the packing depended on the actual packing position within the reactor. The structured packing could be placed horizontally or rotated 90 degrees into the high-gravity rotating bed.

[0018] The present invention provides an impinging stream-rotating packed bed made of the above-mentioned structured packing for use in a liquid-liquid precipitation reaction. The specific reaction process is as follows: Solution A and Solution B are placed in a first liquid storage tank and a second liquid storage tank, respectively. Driven by a pump, the two solutions enter the impinging stream region (the center of the packing) of the impinging stream reactor at a set flow rate. They collide with each other along the nozzle of a liquid distributor, are atomized, and initially mixed, and then enter the rotating packing region. Driven by a motor, the material passes through the packing region layer by layer in a spiral motion from the inner edge of the packing, achieving full dispersion, aggregation, mixing, and reaction of the materials. After the reaction is completed, the desired materials enter a product storage tank under the action of gravity for collection.

[0019] Beneficial effects of the present invention:

[0020] (1) The use of 3D modeling software and 3D printing technology breaks the limitations of traditional filler design, provides more possibilities for the design and development of new fillers, and can further promote the development of supergravity technology;

[0021] (2) This invention shifts the research and development of fillers from overall structural changes to the fine design of the filler's internal channels designed for liquid-liquid precipitation reactions, achieving dispersion and aggregation of the liquid phase. By designing multiple dense-sparse-dense structures, the purpose of improving filler performance is achieved, providing new ideas for the research and development of new fillers between liquid phases;

[0022] (3) The structured packing of the present invention has a large specific surface area and porosity, which greatly reduces the edge effect. While improving the mixing and mass transfer efficiency, the presence of multiple dispersion and mixing structures enables the liquid-liquid two-phase to have good dispersion under the condition of multiple sufficient reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram showing the simulated flow of liquid droplets in a wire mesh filler in the prior art;

[0024] Figure 2 The figure shows the simulated droplet flow of structured packing;

[0025] Figure 3 This is a schematic diagram of the impinging stream-rotating packed bed structure;

[0026] Figure 4 Schematic diagram of the upper and lower support ring structures;

[0027] Figure 5 Schematic diagram of the first dispersed structure;

[0028] Figure 6 Schematic diagram of the second dispersed structure;

[0029] Figure 7 Schematic diagram of the third dispersed structure;

[0030] Figure 8 is a schematic diagram of the first hybrid structure;

[0031] Figure 9 is a schematic diagram of the second hybrid structure;

[0032] Figure 10 Schematic diagram of the assembled multi-ring dispersion and mixing structure;

[0033] Figure 11 Schematic diagram of a three-dimensional structured packing model with a complete supporting structure.

[0034] In the figure: 1 is the first liquid storage tank, 2 is the first pump, 3 is the first flow meter, 4 is the second pump, 5 is the second flow meter, 6 is the second liquid storage tank, 7 is the impinging flow-rotating packed bed reactor, 8 is the product storage tank, 9 is the motor, and 10 is the annular plate. DETAILED DESCRIPTION

[0035] The present invention is further illustrated with reference to the following examples, but is not limited to the following embodiments and should also include any other known changes within the scope of the packing design method protected by the present invention.

[0036] According to the existing technology, Zhang et al. simulated the flow of liquid droplets in the filler, and drew the Figure 1 The droplet distribution diagram is combined with the flow of the droplets by the filler in the high gravity rotating packed bed suitable for liquid-liquid precipitation reaction designed by the present invention. Figure 2 shown. Figure 1 At a rotational speed of 1000 rpm, the droplets undergo radial spiral motion under the influence of various forces, including centrifugal force, packing drag, and Coriolis force. In the inner region, the liquid is relatively concentrated. As it continuously collides with the packing, the radial velocity of the droplets decreases under a certain resistance, gradually moving in the direction of rotation. As it approaches the outer region, the droplets gradually disperse. Figure 2The structured packing model designed by the present invention is added to the droplet flow trajectory and the packing intersect, which is conducive to cutting and dispersion. At the same time, a certain number of arc-shaped blades surrounding the ring eliminate dead corners when the droplets are dispersed, effectively eliminating the existence of stagnant areas.

[0037] like Figures 3 to 11 As shown, the present invention provides a packing structure for a high-gravity rotating packed bed for liquid-liquid precipitation reaction. First, multiple circular rings are constructed using Maxon Cinema 4D software. The circular ring spacer layer is used to construct arc-shaped blades around the circular rings. Each layer of blades has circular holes of uniform size and neatly staggered arrangements. Two circular ring plates are used to cover and fix the packing to construct a regular packing structure model suitable for liquid-liquid precipitation reaction. Then, 3D printing technology is used to convert it into a solid packing.

[0038] A structured packing for a high-gravity rotating packed bed suitable for liquid-liquid precipitation reaction, comprising a dispersion structure, a mixing structure, and a support structure; the support structure is composed of a plurality of concentric support rings and detachable ring plates, and is arranged in parallel up and down, and a dispersion structure and a mixing structure composed of arc-shaped blade structures are provided between two layers of concentric rings; the innermost and outermost layers of the rings are both dispersion structures, and are arranged from the inside out as follows: the multi-layer support ring structure has a total of 2n layers (n ≥ 2 and is a positive integer), wherein the odd-numbered layers, i.e., the 1st layer and the (2n-1)th layer, are dispersion structures, and the arc-shaped blades of the dispersion structure are provided with circular holes with larger apertures; the even-numbered layers (i.e., the 2nth layer) are mixing structures, and the arc-shaped blades of the mixing structure are provided with circular holes with smaller apertures; arc-shaped blades of gradually increasing size are provided in the interval ring layers and are arranged in a circle around the ring layers, i.e., the size of the arc-shaped blades in the dispersion structure and the mixing structure increases as the circle in which they are located increases, and the overall size of the arc-shaped blades tends to gradually increase from the inside out;

[0039] Liquid droplets passing through the dispersion and mixing structures pass through multiple curved blades, each uniformly provided with a number of circular holes of uniform aperture. Vertically adjacent circular holes on the blades are staggered at 45 degrees, with the aperture gradually decreasing and the number increasing from the inside out. The curved blades of the dispersion and mixing structures are respectively connected and fixed to supporting circular rings on their left and right sides. Specifically, one vertical edge of the curved blades of the two structures is connected to the inner circular ring, and the other vertical edge is connected to the outer circular ring. Furthermore, one vertical edge of the curved blade of the dispersion structure intersects with a vertical edge of the curved blade of the adjacent mixing structure, ultimately forming a "Z"-shaped structure. Finally, a removable circular plate structure is used to secure the support structures of the upper and lower layers of the packing. A three-dimensional packing model with an overall "Z"-shaped multi-layer structure can be obtained from above. This model has multiple components that facilitate segmentation and mixing, effectively achieving the aggregation and dispersion of droplets and reducing material retention. Ultimately, 3D printing technology was used to print the solid packing.

[0040] Specifically, the inner and outer diameters of the adjacent concentric rings are increased by 1.1 to 1.5 times. The innermost ring has an outer diameter (D) of 40 to 400 mm and a thickness of 1 to 2 mm. If the rotating packed bed is larger, the ring diameter can be further increased. On this basis, the adjacent outer diameters of the rings are enlarged by (1.1 to 1.5) × D to create a multi-layered ring structure. The distance between the upper and lower rings is H = 40 to 300 mm (this size can be adjusted according to actual conditions). To enhance the dispersion effect, a multi-layered arc-shaped blade structure is installed between the two rings, with a circle of arc-shaped blades between each adjacent ring.

[0041] The structure of the curved blades is described as follows: the central angle of the blades ranges from 15° to 45°. The blades are uniformly provided with circular holes, with a size d ranging from 2 to 6 mm, and are staggered d / 2 between the upper and lower layers. The spacing between the holes is approximately d / 2 to 2d, and the aperture ratio is 60% to 70%. Too dense a density of holes will reduce the space for liquid flow, and a 1-5 mm space is required around the blades to allow them to fit into the rings. The curved blades are placed within two adjacent layers of supporting rings of the packing, with one end connected to the outer ring and the other to the inner ring. Furthermore, the curved blades in the dispersion structure rotate in the opposite direction to the reactor motor, meaning that the reactants pass through them in a staggered manner. The curved blades in the mixing structure rotate in the opposite direction to the former, following the direction of motor rotation.

[0042] The arcuate blade structure is placed within each layer of circular rings, with the spacing between adjacent layers of rings ≥5 mm. Concentric rings embed and secure 1-2 mm thick arcuate blades. From the inside out, the curvature and length of the blades change with increasing radius across all layers. In a dispersed structure, the angle between the blades in odd-numbered layers of rings and the inner ring of the ring layer is 35°-40°, followed by 15°-20° and 5°-10°. The angle decreases toward the outermost layer, and the appropriate number of ring layers and blades can be selected based on the actual packing size. In a mixed structure, the angle increases between even-numbered layers of rings and toward the outermost layers.

[0043] For the determination of the number of arc-shaped blades, both the dispersed structure and the mixed structure are consistent. The circumference of the ring is set to C. Since the ring is closed, the number of arc-shaped blades is set to m. Since the ring size needs to be selected according to the actual equipment, the interval d of the arc-shaped blades in the same ring is: d=C / m.

[0044] The number, size, and arrangement of the circular holes within the arcuate blades vary from the inner to the outer layers of the packing. This shift in orientation creates a multi-layered "Z"-shaped structure. Furthermore, as the radius of the ring increases, the number of holes increases and the radius decreases, facilitating multiple dispersion and aggregation of the product and unreacted raw materials, ensuring a complete reaction.

[0045] The multi-ring structure and the curved blade structure are relatively weak, so 1-6 mm thick removable ring plates are embedded on the upper and lower sides of the rings to support and fix the filler. The ring plates are located between the two supporting rings.

[0046] The method for constructing the structured packing structure is as follows: First, the structured packing model is designed using Maxon Cinema 4D 3D modeling software. Using a circular ring structure as the foundation, multiple circular ring structures are arranged along a radius around the same center, creating a multi-ring structure. Curved blade structures are embedded within the rings at a predetermined angle. Furthermore, removable circular plates are added above and below the rings to secure the packing, completing the packing structure. The solid packing is then printed using 3D printing technology, and the structured packing model is designed using Maxon Cinema 4D software. The software's design freedom allows the design of the dispersed, mixed, and support structures required for the 3D packing model.

[0047] The structure of the packing provided in this embodiment is as follows: the inner diameter is 42 mm, the outer diameter is 160 mm, and the height of the packing (ie, the distance between the upper and lower rings) is 40 mm.

[0048] The two circular rings enclosing curved blades form a dispersed or mixed structure for the packing. The innermost layer is a dispersed structure, and upon impact, the liquid enters the innermost layer of the packing radially. The dispersed structure within the packing effectively disperses, tears, and shears the liquid. In the impinging stream-rotating packed bed, centrifugal force causes droplets to spiral in the direction of rotation. The curved blades, however, oppose this rotation, causing the droplets to cross and stagger contact with the packing holes, facilitating tearing and dispersion. Furthermore, the impediment of the packing blades smooths out droplet splashing, while the multi-layered dispersed structure near the outer diameter reduces its curvature and increases its specific surface area, achieving multiple dispersions of the droplets.

[0049] The curved blades, facing in the opposite direction from the dispersion structure, combine with the two circular rings to form the packing's mixing structure. While the initial dispersion structure doesn't guarantee a complete reaction between the two liquid phases, unreacted material may remain. The mixing structure allows splashed droplets to further mix and react. Furthermore, the ample circular hole space also reduces clogging to a certain extent.

[0050] The multi-layered curved blade structure varies in radius, curvature, and length, significantly minimizing edge under-reaction. Longer blades have smaller and more numerous internal holes, achieving better liquid redispersion. A circular plate covers the rings and curved blades, making the packing structure more secure and stable. This arrangement creates a three-dimensional structured packing model of a specific specification.

[0051] There are arc-shaped blade structures between adjacent rings, forming a first dispersion structure, such as Figure 5The first arc-shaped blade shown in a has an angle of 35°~40° with the inner ring. 8 blades are evenly arranged along the circumference in a unit of 45°. Figure 5 As shown in b, it is embedded in the ring sandwich 1 mm. Each arc-shaped leaf has a 4 mm diameter circular hole, with a vertical spacing of 0.5 mm and a horizontal spacing of 1 mm. The circular holes are arranged in 3 columns and 9 rows, and are combined with circular rings with an outer diameter of 44 mm and a thickness of 2 mm and an outer diameter of 64 mm and a thickness of 2 mm to form the first dispersed structure, as shown in Figure 5 As shown in Figure c, during the impinging stream reactor's impingement atomization, i.e., after the initial reaction, droplets are radially cut by the dispersion structure from the inner edge of the packing. Furthermore, the rotation of the packing disperses the droplets that are in circumferential motion after the reaction.

[0052] The second dispersed structure is similar to the first dispersed structure. Figure 6 In unit a, the angle between the blade and the inner ring is 15°~20°, and its complete arc blade structure is as follows Figure 6 As shown in unit b in the figure, the 3 mm diameter circular holes are staggered in 7 columns and 12 rows. As the radius increases, the length of the arc blades of the second dispersion structure also increases in order to achieve full coverage of the dispersion. Together with the two circular rings with an outer diameter of 88 mm and a thickness of 2 mm and an outer diameter of 112 mm and a thickness of 2 mm, a complete second dispersion structure is formed, as shown in the figure. Figure 6 Unit c in .

[0053] The third dispersed structure is similar to the first and second dispersed structures. Figure 7 In unit a, the angle between the blade and the inner ring is 5°~10°, and its complete arc blade structure is as follows Figure 7 As shown in unit b in the figure, the 2 mm diameter circular holes are staggered in 15 columns and 18 rows. The arc-shaped blades of the third dispersed structure and the two circular rings with an outer diameter of 136 mm and a thickness of 2 mm and an outer diameter of 160 mm and a thickness of 2 mm form a complete third dispersed structure, as shown in the figure. Figure 7 Unit c in .

[0054] The first hybrid structure, such as Figure 8 The blade direction of unit a in the packing is opposite to that of the dispersed structure (the arrangement direction of the two in the packing). The complete arc blade structure is as follows: Figure 8 As shown in unit b in the figure, the circular holes with a diameter of 3.5 mm are arranged in 5 columns and 11 rows. This structure is connected with two dispersed blades to form a "Z"-shaped structure, as shown in Figure 8 The second hybrid structure is similar to the first hybrid structure, such as Figure 9As shown in the units a, b, and c, the circular holes with a diameter of 2.5 mm are arranged in 9 columns and 15 rows. The three dispersed structures and the two mixed structures are combined to form Figure 10 Integral fillers such as Figure 10 As shown in units a and b (top view), they form multiple "Z"-shaped structures, namely, a multi-ring packing structure with blades that disperse-mix-disperse-mix-disperse, which improves its mass transfer efficiency. The blade curvature is oriented opposite to the direction of rotation of the rotating packed bed, and the sprayed droplets contact the packing blades in a cross-shaped pattern. The blade curvature is oriented in the same direction as the rotating packed bed, and the droplets gather, mix, and react along the blades, passing through six concentric rings in sequence. On the one hand, the dispersion structure has a good dispersion and shearing effect, without dead spots, and the blade volume distribution is relatively non-dense, which is not easy to clog the packing. On the other hand, the dispersed materials are more or less incompletely mixed. The mixing structure allows the scattered droplets to contact and further fully react.

[0055] The blade thickness is 1 mm and the support is not strong. Two removable circular plates 10 are embedded on the upper and lower sides of the packing ring (see Figure 11 Finally, a suitable 3D printer was selected to print the solid filler, which was then placed in an impinging stream-rotating packed bed to replace the original filler for liquid-liquid precipitation reaction.

[0056] Figure 11 A schematic diagram of a three-dimensional structured packing model with a complete support structure is given. According to the actual device, the structured packing is rotated 90° and placed Figure 3 As shown, the impinging stream is used in a rotating packed bed.

[0057] The structured packing is used in Figure 3 The illustrated impinging stream-rotating packed bed apparatus includes storage tanks for liquid-liquid two-phase solutions: a first liquid storage tank 1, a second liquid storage tank 6, a product storage tank 8, a pump, a rotameter, an impinging stream-rotating packed bed reactor 7, and a motor 9. The liquid-liquid contact reaction process is as follows: the two liquids enter the impinging stream region under the action of the pump, collide along the nozzle, and are atomized before entering the rotating packed bed. Driven by the motor, the packing rotor moves the material from the inner edge of the packing layer by layer in a spiral motion from the inside out, achieving thorough dispersion, mixing, and further reaction. After the reaction is complete, the material is collected in the product storage tank under the action of gravity.

[0058] Figure 3 The application device of the filler is given. Taking the preparation process of barium strontium titanate precursor as an example, solution A is a mixed solution of barium chloride, strontium chloride, and titanium tetrachloride, and solution B is a 2 mol / L sodium hydroxide solution. The specific reaction process is as follows:

[0059] (1) Prepare 0.5 mol / L barium chloride and strontium chloride solutions respectively;

[0060] (2) To prevent excessive hydrolysis of titanium tetrachloride to produce hydrated titanium dioxide, first dilute hydrochloric acid to 0.3 mol / L and seal it in a refrigerated environment at 5°C. Then, take 500 mL of the refrigerated hydrochloric acid solution in a beaker and place it in a magnetic stirrer. Use a dry pipette to take 27.474 mL of titanium tetrachloride and slowly drip it into the hydrochloric acid solution to obtain a slightly transparent hydrochloric acid solution of titanium tetrachloride.

[0061] (3) Mix the barium chloride solution, strontium chloride solution and titanium tetrachloride hydrochloric acid solution and stir until uniformly mixed to obtain solution A;

[0062] (4) Prepare an appropriate amount of 2 mol / L sodium hydroxide solution and mix it evenly in a beaker to obtain solution B.

[0063] (5) The reaction process is as follows Figure 3 As shown, solution A and solution B are placed in the first liquid storage tank 1 and the second liquid storage tank 6 respectively. Driven by a pump, the two solutions enter the impinging stream reactor at the required flow rate to collide with each other, mix and react. The mist surface formed by the collision will then enter the inner side of the rotating packed bed and be driven by a motor to rotate and mix again. The products after the mixed reaction flow into the product storage tank 8 under the action of gravity.

[0064] The barium strontium titanate product obtained by using the filler of the present invention has uniform particle distribution, narrow particle size distribution and good dispersibility. At the same time, the filler used in the present invention is also more convenient to disassemble and clean.

[0065] The above embodiments are only some implementation methods of the present invention, and are not limitations of the present invention. For other different forms of changes or modifications in the relevant field, all obvious changes derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A structured packing for a high gravity rotating bed for liquid-liquid precipitation reaction, characterized in that: It includes a dispersed structure, a mixed structure, and a support structure; the support structure is composed of a number of concentric support rings and detachable ring plates, and is arranged in parallel up and down. A dispersed structure and a mixed structure composed of an arc-shaped blade structure are arranged between the two layers of concentric rings; circular holes are evenly arranged on the arc-shaped blades, and the hole diameter d is 2~6 mm. The holes in the upper and lower layers are staggered d / 2. The innermost and outermost layers of the rings are both dispersed structures, and are arranged from the inside to the outside: the multi-layer support ring structure has a total of 2 n layer, n ≥2 and is a positive integer; the odd-numbered layers are dispersed structures, and the arc-shaped blades of the dispersed structure are provided with circular holes of larger apertures; the even-numbered layers are mixed structures, and the arc-shaped blades of the mixed structure are provided with circular holes of smaller apertures; the arc-shaped blades of gradually increasing size are arranged in a circle around the ring layer, that is, the size of the arc-shaped blades in the dispersed structure and the mixed structure increases as the circle in which they are located increases, and the overall size of the arc-shaped blades increases from the inside to the outside respectively; Each arc-shaped blade is evenly provided with a number of circular holes of the same aperture size. The adjacent circular holes in the vertical direction on the blade are staggered at 45 degrees, and the aperture gradually decreases and the number gradually increases from the inside to the outside. The left and right sides of the arc-shaped blades with a dispersed structure and a mixed structure are respectively connected and fixed to the supporting circular rings. Specifically: one vertical side of the arc-shaped blade is connected to the inner circular ring, and the other vertical side is connected to the outer circular ring. A vertical side of the arc-shaped blade with a dispersed structure intersects with a vertical side of the arc-shaped blade of the adjacent mixed structure, eventually forming a "Z"-shaped structure; finally, a detachable circular plate structure is used to fix the supporting circular ring structure of the upper and lower layers of the filler.

2. The structured packing for a high gravity rotating bed for liquid-liquid precipitation reaction according to claim 1, characterized in that: The diameters of the adjacent inner and outer layers of the concentric rings are enlarged by 1.1 to 1.5 times; the dimensions of the innermost ring are: outer diameter D is 40 to 100 mm, and thickness is 1 to 2 mm. If the rotating packed bed is larger, the diameter of the ring is further enlarged. On this basis, the diameters of the adjacent outer layers of the rings are enlarged by (1.1 to 1.5) × D to construct a multi-layer ring structure, and the distance between the upper and lower rings is H = 40 to 300 mm; to improve the dispersion effect, a multi-layer arc blade structure is set between the two rings, and a circle of arc blades is set between each adjacent ring.

3. The structured packing for a high gravity rotating bed for liquid-liquid precipitation reaction according to claim 1, characterized in that: The central angle range of the arc-shaped blades is 15~45°, the upper and lower spacing and the left and right spacing of the circular holes of the arc-shaped blades are d / 2~2d, and the opening rate is 50%~80%. Too dense will lead to a reduction in the liquid flow space, and a space of 1~5 mm must be left around the blades to be embedded in the ring.

4. The structured packing for a high gravity rotating bed for liquid-liquid precipitation reaction according to claim 3, characterized in that: The arc-shaped blade structure is placed in each layer of circular rings, and the difference in spacing between adjacent layers of circular rings is ≥5 mm. Concentric circular rings are embedded and fixed with arc-shaped blades 1 to 2 mm thick. From the inside out, as the radius increases, the curvature and length of the blades in all layers change accordingly. In the dispersed structure, the angle between the blades between the odd-numbered layers of circular rings and the inner ring of the circular layer is 35° to 40°, and then 15° to 20° and 5° to 10° respectively. The closer to the outermost layer, the smaller the angle. The appropriate number of circular ring layers and blades is selected according to the actual size of the filler. In the mixed structure, the angle between the even-numbered layers of circular rings and the outermost layer is larger.

5. The structured packing for a high gravity rotating bed for liquid-liquid precipitation reaction according to claim 1, characterized in that: In the support structure, a detachable circular plate with a thickness of 1 to 6 mm is embedded between adjacent supporting circular rings to support and fix the filler.

6. A method for constructing a structured packing according to any one of claims 1 to 5, characterized in that: First, a regular packing model was designed using Maxon Cinema 4D 3D modeling software. Based on a circular ring structure, multiple circular ring structures were set along the radius with the same center to construct a multi-circular ring structure. Arc-shaped blade structures at a certain angle of 15 to 45 degrees were embedded in the rings. Removable circular ring plates were then added above and below the rings to fix the packing, thus forming a complete packing structure. The solid packing was then printed using 3D printing technology.

7. A high gravity rotating bed made of the structured packing according to any one of claims 1 to 5, characterized in that: Place the structured packing horizontally or rotated 90° into the high gravity rotating bed.

8. Use of the high gravity rotating bed according to claim 7 in a liquid-liquid precipitation reaction.

9. The use according to claim 8, characterized in that: Solution A and solution B are placed in the first liquid storage tank and the second liquid storage tank respectively. Driven by the pump, the two solutions enter the impinging stream area of ​​the impinging stream reactor at a set flow rate, collide with each other along the nozzle of the liquid distributor and are atomized before entering the rotating packing area. Under the action of the motor, the material passes through the packing area layer by layer in a spiral motion from the inner edge of the packing to the outside, achieving full dispersion, aggregation, mixing and reaction of the materials; after the reaction is completed, the required materials enter the product storage tank for collection under the action of gravity or pressure.

Images