Device and method for improving bulk density of catalyst and catalyst

Abstract

The invention relates to the technical field of catalyst treatment, and particularly provides a device and method for improving the bulk density of a catalyst and the catalyst. The device for improving the bulk density of the catalyst comprises a drying kettle, a heating jacket, a stirrer, a plurality of solvent filters, a vacuum unit and a back flushing unit, the heating jacket is arranged on the outer wall of the drying kettle, the stirrer extends into an inner cavity of the drying kettle, the plurality of solvent filters are arranged at the bottom of the drying kettle and communicated with the inner cavity of the drying kettle, and the vacuum unit is communicated with the back flushing unit. The plurality of solvent filters are uniformly distributed along the circumferential direction of the drying kettle, the vacuum unit is communicated with an inner cavity of the drying kettle, and the back flushing unit is respectively communicated with the plurality of solvent filters. The device and the method for improving the bulk density of the catalyst and the catalyst provided by the invention are used for obtaining the catalyst with high bulk density, regular form and concentrated particle size distribution.

Description

Technical Field

[0001] This disclosure relates to the field of catalyst processing technology, and more particularly to an apparatus, method and catalyst for increasing the bulk density of a catalyst. Background Technology

[0002] Ziegler-Natta catalysts are core components in polyolefin polymerization. Their physical form, especially bulk density, determines the powder morphology and bulk density of the produced polymer (such as ultra-high molecular weight polyethylene). High bulk density catalysts are beneficial for improving the production efficiency of polymerization units, reducing the generation of fine powder, and improving the flowability of polymer products.

[0003] Currently, the commonly used industrial methods for catalyst drying are high-temperature drying and spray drying. High temperatures can easily cause catalyst particles to fuse, collapsing their internal pore structure and reducing their bulk density. While spray drying can control particle morphology, its high inlet temperature can damage the catalyst's active sites, and the process easily generates a large amount of fine powder, resulting in an excessively wide catalyst particle size distribution, which is difficult to meet the requirements for ultra-high molecular weight polyethylene production. Summary of the Invention

[0004] This disclosure is made in view of the above-mentioned problems. This disclosure provides an apparatus, method and catalyst for increasing the bulk density of a catalyst, which can obtain a catalyst with high bulk density, regular morphology and concentrated particle size distribution.

[0005] According to a first aspect of this disclosure, an apparatus for increasing the bulk density of a catalyst is provided, comprising: a drying vessel, a heating jacket, a stirrer, a plurality of solvent filters, a vacuum unit, and a backflushing unit. The heating jacket is disposed on the outer wall of the drying vessel, the stirrer extends into the internal cavity of the drying vessel, the plurality of solvent filters are disposed at the bottom of the drying vessel and communicate with the internal cavity of the drying vessel, the plurality of solvent filters are uniformly distributed along the circumference of the drying vessel, the vacuum unit communicates with the internal cavity of the drying vessel, and the backflushing unit is communicated with each of the plurality of solvent filters.

[0006] According to a second aspect of this disclosure, a method for increasing the bulk density of a catalyst is provided, applicable to an apparatus for increasing the bulk density of a catalyst according to embodiments of this disclosure, comprising the following steps: Step 201: The slurry containing the catalyst and solvent is fed into a drying kettle and filtered through multiple solvent filters to form a catalyst filter cake; Step 202: Under the stirring action of the stirrer, turn on the heating jacket and vacuum unit, and dry the catalyst filter cake at a temperature below the boiling point of the solvent and under reduced pressure. Step 203: Use the backflushing unit to introduce backflushing medium into the solvent filter to backflush the catalyst filter cake; Step 204: Repeat steps 202 and 203 until the solvent residue of the catalyst is less than 10 ppm.

[0007] According to a third aspect of this disclosure, a catalyst is provided, prepared according to the method for increasing the bulk density of a catalyst as described in the second aspect, wherein the bulk density of the catalyst is ≥0.35 g / cm³. 3 The catalyst has a specific surface area of ​​202 m². 2 / g~280m 2 / g.

[0008] Compared with the prior art, the apparatus, method, and catalyst provided in this disclosure for increasing the bulk density of a catalyst have the following advantages: In one or more technical solutions provided in this disclosure, the device first includes a drying kettle, a heating jacket, a stirrer, multiple solvent filters, a vacuum unit, and a backflushing unit. The multiple solvent filters are located at the bottom of the drying kettle and communicate with its internal cavity. Therefore, a slurry containing catalyst and solvent can be fed into the drying kettle and filtered through the multiple solvent filters to form a catalyst filter cake. This allows for rapid separation of the catalyst and solvent. The multiple solvent filters are evenly distributed along the circumference of the drying kettle, ensuring a uniform and efficient filtration rate and preventing excessive localized filter cake buildup, thus initially regulating the packing state of the catalyst particles. Then, under the stirring action of the stirrer, the heating jacket and vacuum unit are activated. The catalyst filter cake is dried at a temperature below the solvent boiling point and under reduced pressure. This not only prevents high temperatures from causing catalyst particle melting and pore structure collapse but also accelerates solvent evaporation. Combined with the mechanical action of the stirrer, this ensures uniform dispersion and thorough drying of the catalyst particles, further optimizing the particle packing density and effectively protecting the catalyst's active centers. Next, a backflushing medium is introduced into the solvent filter using a backflushing unit to backflush the catalyst filter cake. This effectively removes catalyst particles adhering to the filter surface, prevents filter pore blockage, and ensures the continuity of the filtration and drying processes. Simultaneously, the impact force of the backflushing breaks up any small agglomerated particles in the filter cake, resulting in more regular catalyst particle morphology and reducing the generation of fine powder. Subsequently, the drying and backflushing steps are repeated until the solvent residue in the catalyst is below 10 ppm. Through the cyclical operation of drying and backflushing, deep solvent removal and continuous optimization of the particle structure are achieved, ultimately yielding a catalyst with high bulk density, concentrated particle size distribution, and a solvent residue below 10 ppm. Attached Figure Description

[0009] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0010] Figure 1 This is a schematic diagram of the structure of an apparatus for increasing the bulk density of a catalyst according to an embodiment of this disclosure; Figure 2 This is a flowchart of a method for increasing the bulk density of a catalyst according to an embodiment of this disclosure.

[0011] Figure label: 101 Drying vessel, 102 Stirrer, 102a Stirring head, 103 Solvent filter. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, and not all embodiments of this disclosure. It should be understood that this disclosure is not limited to the exemplary embodiments described herein.

[0013] Ultra-high molecular weight polyethylene (UHMWPE) is a high-performance engineering plastic with excellent impact resistance, abrasion resistance, self-lubrication, and chemical stability. It is widely used in mining, food, chemical, papermaking, textile, and construction machinery industries. However, its extremely high molecular weight (typically exceeding 1.5 million) results in extremely high melt viscosity and poor flowability, posing significant challenges to processing and molding, thus limiting the large-scale application and promotion of UHMWPE materials.

[0014] In the synthesis of ultra-high molecular weight polyethylene, the catalytic system is the core factor determining the polymer's properties and processability. In the field of polyolefins, the powder morphology and bulk density of the catalyst largely determine the morphology of the final polymer particles.

[0015] Currently, the commonly used drying methods for Ziegler-Natta catalysts in industry are high-temperature drying, atmospheric pressure drying, or spray drying. Ziegler-Natta catalysts have a porous structure with numerous internal pores that can adsorb hexane solvent. During drying, the hexane solvent adsorbed on the catalyst particles desorbs, and the desorption rate determines the catalyst morphology. Therefore, at high temperatures (>68°C), the solvent desorption rate is rapid. During solvent removal, particle melting can occur, damaging the catalyst particles and causing the internal pore structure to collapse, thus reducing the bulk density. Atmospheric pressure drying is prone to particle breakage due to excessively rapid solvent evaporation, forming internal pores. While spray drying can control particle morphology, its high inlet temperature can easily damage the catalyst's active sites, and the process easily generates a large amount of fine powder, resulting in an excessively wide catalyst particle size distribution, which is difficult to meet the requirements of ultra-high molecular weight polyethylene production.

[0016] To address the aforementioned issues, this disclosure provides an apparatus for increasing the bulk density of a catalyst, effectively overcoming problems such as particle fusion, pore destruction, excessive fine powder, and damage to active centers caused by traditional high-temperature drying and spray drying, ultimately obtaining a high-performance catalyst with high bulk density, regular morphology, and concentrated particle size distribution.

[0017] Figure 1 A schematic diagram of an apparatus for increasing catalyst packing density according to an embodiment of this disclosure is shown. Figure 1 As shown, the apparatus for increasing the bulk density of a catalyst according to an embodiment of this disclosure includes: a drying vessel 101, a heating jacket (not shown in the figure), a stirrer 102, a plurality of solvent filters 103, a vacuum unit (not shown in the figure), and a backflushing unit (not shown in the figure). The heating jacket is disposed on the outer wall of the drying vessel 101, the stirrer 102 extends into the internal cavity of the drying vessel 101, the plurality of solvent filters 103 are disposed at the bottom of the drying vessel 101 and communicate with the internal cavity of the drying vessel 101, the plurality of solvent filters 103 are evenly distributed along the circumference of the drying vessel 101, the vacuum unit is communicated with the internal cavity of the drying vessel 101, and the backflushing unit is communicated with the plurality of solvent filters 103 respectively.

[0018] It is understood that the number of solvent filters 103 can be 3 to 8, preferably 3 to 6, and the spacing between each solvent filter 103 is equal. By uniformly distributing multiple solvent filters 103 at the bottom of the drying vessel 101, the uniformity of filtration and backflushing can be significantly improved, ensuring a uniform and efficient filtration rate, avoiding excessively thick local filter cake accumulation, and initially regulating the packing state of catalyst particles. The heating jacket can be set on the outer wall of the drying vessel 101, using heat transfer oil or steam as the heat medium to achieve uniform heating of the material inside the drying vessel 101, avoiding local overheating, and ensuring that the catalyst maintains its complete particle morphology and pore structure during low-temperature vacuum drying.

[0019] The aforementioned vacuum unit can be a liquid ring vacuum pump, and the aforementioned backflush unit can be a gas supply system equipped with a gas heater, a pressure regulating valve, and a pulse controller, using nitrogen as the medium to provide backflush airflow to the solvent filter in a pulse mode.

[0020] In practice, the slurry containing catalyst and solvent is first fed into the drying kettle 101 and filtered through multiple solvent filters 103 to form a catalyst filter cake, thus quickly separating the catalyst and solvent. Then, under the stirring action of the stirrer 102, the heating jacket and vacuum unit are turned on to dry the catalyst filter cake at a temperature below the solvent boiling point and under reduced pressure. This not only avoids the catalyst particles from melting and the pore structure from collapsing due to high temperature, but also accelerates solvent evaporation. Combined with the mechanical action of the stirrer 102, the catalyst particles are evenly dispersed and fully dried, further optimizing the density of particle packing and effectively protecting the active centers of the catalyst. Next, the backflushing unit introduces backflushing medium into the solvent filter 103 to backflush the catalyst filter cake. This effectively removes catalyst particles adhering to the filter surface, prevents filter pore blockage, and ensures the continuity of the filtration and drying process. At the same time, the impact force of the backflushing can break up the small number of agglomerated particles in the filter cake, making the catalyst particles more regular in shape and reducing the generation of fine powder. Subsequently, the drying and backflushing steps were repeated to achieve deep solvent removal and continuous optimization of particle structure, ultimately resulting in a catalyst with high bulk density, concentrated particle size distribution, and solvent residue of less than 10 ppm.

[0021] In one feasible way, such as Figure 1 As shown, the bottom of the drying vessel 101 in this embodiment is configured as a converging structure for concentrating materials, and the bottom of the stirrer 102 is provided with a stirring head 102a that matches the converging structure of the drying vessel 101. The cross-sectional area of ​​the converging structure gradually decreases from top to bottom, forming a flow channel that guides the materials to concentrate towards the center. Working in conjunction with the matching stirring head 102a, it ensures that the catalyst particles achieve uniform three-dimensional tumbling during the drying process, effectively preventing localized overheating and promoting uniform evaporation of the solvent, thus ensuring the integrity of the catalyst particle morphology and a significant increase in bulk density.

[0022] For example, the above-mentioned convergence structure can be any one of a conical structure, an inverted frustum structure, or a parabolic structure, preferably a conical structure. This embodiment uses a conical structure as an example of the convergence structure. When the convergence structure is conical, the cone angle is preferably 45°~75°, more preferably 60°, which can ensure smooth material concentration while avoiding the formation of flow dead zones.

[0023] In one alternative embodiment, the stirring head 102a of this disclosure has an angle with the horizontal direction, the angle being 45° to 75°, preferably 60°.

[0024] In practical applications, the aforementioned angle range ensures that the stirring head 102a generates sufficient upward pushing force on the material, while also guiding the catalyst particles along the inner wall of the converging structure towards the center through the inclined surface, preventing particles from adhering and accumulating on the conical wall. Specifically, the aforementioned angle design is adapted to the conical converging structure at the bottom of the drying vessel 101. The axial force generated by the stirring head 102a during stirring can break up the dense catalyst filter cake settled at the bottom, allowing the particles to redisperse and then accumulate evenly. The radial force, combined with the guiding effect of the converging structure, allows the particles to concentrate orderly along the flow channel, reducing the generation of fine powder caused by irregular collisions and further improving the density of particle accumulation.

[0025] For example, the stirrer 102 is a ribbon stirrer, which is integrally formed by a vertical ribbon and a stirring head 102a. The ribbon stirrer pushes the catalyst particles at the bottom of the drying vessel upward through the progressive pushing of the spiral surface. This can both disperse the slightly agglomerated particles in the filter cake and avoid the catalyst particles from breaking due to strong impact, thereby reducing the generation of fine powder.

[0026] In some examples, the distance between the outer edge of the stirrer 102 and the inner wall of the drying vessel 101 in this embodiment of the present disclosure is 2mm to 5mm, preferably 3mm. By reducing the distance between the outer edge of the stirrer 102 and the inner wall of the drying vessel 101 to the millimeter level, this embodiment of the present disclosure ensures that the catalyst particles near the inner wall can also be fully driven by the stirring head, achieving uniform agitation throughout the entire vessel, thereby preventing local overheating that could lead to particle melting. Simultaneously, it avoids excessive shearing and breakage of the particles due to excessively small spacing. Therefore, it ensures both the uniform mass and heat transfer effect of the stirrer 102 on the material and maintains the morphological integrity of the catalyst particles, providing a guarantee for obtaining a catalyst product with high bulk density and low fine powder content.

[0027] In some examples, the pore size of each solvent filter 103 in this disclosure embodiment is 10 μm to 40 μm, preferably 15 μm to 30 μm. On the one hand, this pore size can effectively block catalyst particles from entering the solvent discharge channel through the filter, preventing catalyst loss and ensuring the recovery rate of catalyst in the slurry. On the other hand, a pore size of 10 μm to 40 μm will not excessively intercept tiny impurities or low-molecular-weight byproducts in the solvent, ensuring smooth solvent filtration and avoiding problems such as rapid clogging of filter pores and sudden increase in filtration pressure due to excessively small pore size. Therefore, the packing layers of catalyst particles can be initially organized during the filtration stage, preventing fine particles from randomly filling inside the filter cake and laying a uniform particle distribution foundation for subsequent increases in bulk density.

[0028] In some examples, the diameter of each solvent filter 103 in this disclosure embodiment is 100mm to 250mm, preferably 150mm, which ensures that the effective filtration area of ​​a single filter is moderate. At the same time, it also allows the subsequent backflushing medium (such as nitrogen gas at 40°C to 50°C) to act evenly on the entire end face of the filter, avoiding dead corners of filter holes caused by incomplete local backflushing.

[0029] In some examples, the length-to-diameter ratio of the drying vessel 101 in this embodiment of the present disclosure is 1:1 to 1:2, preferably 1:1 to 1:1.5. By controlling the length-to-diameter ratio within this range, the problem of bottom material compaction caused by an excessively large length-to-diameter ratio is avoided, while the uneven drying phenomenon caused by an excessively small length-to-diameter ratio is prevented.

[0030] In one possible implementation, embodiments of this disclosure also provide a method for increasing the bulk density of a catalyst, applied to the apparatus for increasing the bulk density of a catalyst according to embodiments of this disclosure. Figure 2 A flowchart of a method for increasing the bulk density of a catalyst according to an embodiment of this disclosure is shown, such as... Figure 2 As shown, the method for increasing the bulk density of a catalyst according to embodiments of this disclosure includes: Step 201: The slurry containing the catalyst and solvent is fed into a drying kettle and filtered through multiple solvent filters to form a catalyst filter cake.

[0031] It should be understood that the catalysts mentioned above can be Ziegler-Natta type polyolefin catalysts, including but not limited to magnesium-titanium catalyst systems used in the production of ultra-high molecular weight polyethylene, high-density polyethylene, or polypropylene. These catalysts are typically dispersed in a solvent in the form of solid particles. The solvents mentioned above can be alkane solvents with 5 to 10 carbon atoms, including but not limited to hexane and heptane.

[0032] For example, a Ziegler-Natta catalyst-hexane slurry with a solid content of 10%~20% is transferred to a drying reactor. The hexane solvent is removed by filtering through multiple solvent filters at the bottom of the reactor, forming a catalyst filter cake with a moisture content of <40%. This moisture content avoids both excessive dryness leading to loose particles and excessive moisture causing excessive solvent evaporation load during the drying stage. It allows the particles within the filter cake to form a loose but orderly initial structure, which, after subsequent drying, dehydration, and backflushing, more easily forms a dense and regularly shaped aggregate.

[0033] Step 202: Under the stirring action of the stirrer, turn on the heating jacket and vacuum unit, and dry the catalyst filter cake at a temperature below the boiling point of the solvent and under reduced pressure.

[0034] For example, the stirrer 102 is turned on and controlled to run at a speed of 5 rpm to 20 rpm. Simultaneously, the heating jacket and vacuum unit are activated. The heating jacket controls the internal temperature of the drying vessel 101 within the range of 40℃ to 60℃, while the vacuum unit maintains a vacuum level of 30 kPa to 80 kPa within the drying vessel 101. Under these conditions, the catalyst filter cake is subjected to low-temperature reduced-pressure drying for 4 to 10 hours.

[0035] Utilizing a stirring speed of 5 rpm to 20 rpm, the combined motion of the ribbon agitator ensures uniform agitation of the catalyst material within the drying vessel, preventing localized cake agglomeration or overheating due to prolonged static storage. This also reduces shear damage to the catalyst particles, particularly for easily breakable types such as brittle metallocene catalysts, effectively decreasing the fine powder formation rate and ensuring particle morphology integrity. The temperature control within the drying vessel 101, at 40℃ to 60℃, is lower than the boiling points of commonly used solvents such as hexane and heptane, and far below the melting temperature of the catalyst particles. This prevents damage to active centers and collapse of the pore structure caused by high temperatures, while providing stable heat for solvent evaporation. Combined with the low-pressure environment created by a vacuum of 30 kPa to 80 kPa, the solvent vapor pressure is significantly increased, accelerating solvent diffusion from the interior to the surface of the filter cake, improving drying efficiency. Simultaneously, it avoids violent boiling of the filter cake, preventing explosive boiling and loosening, thus laying a foundation for dense packing and subsequent increases in bulk density.

[0036] Step 203: Use the backflushing unit to introduce backflushing medium into the solvent filter to backflush the catalyst filter cake. The backflushing medium is nitrogen gas heated to 40℃~50℃, and the backflushing pressure is 0.1MPa~0.3MPa.

[0037] In practice, a pulsed backflushing mode is adopted, in which the drying vessel is backflushed through multiple solvent filters. This backflushing process uses hot nitrogen to penetrate the catalyst filter cake layer. First, it can effectively remove fine catalyst particles that are clogging the micropores of the filter, restoring the filtration channels to unobstructed flow. Second, the airflow impact force can break up the solvent retention zones formed inside the catalyst filter cake due to capillary action, promoting the migration of deep solvents to the surface. Moreover, the periodic airflow disturbance reconstructs the particle packing structure, allowing the catalyst particles to form a denser packing morphology.

[0038] Step 204: Repeat steps 202 and 203 until the solvent residue of the catalyst is less than 10 ppm.

[0039] In practice, by repeating steps 202 and 203 2-3 times, the solvent residue can be stably controlled below 10 ppm, which is far lower than that of traditional drying processes (typically 50-100 ppm). The resulting catalyst has a bulk density ≥ 0.35 g / cm³. 3 Specific surface area is 202m² 2 / g~280m2 / g achieves a balance between high bulk density and high activity. This avoids interference from residual solvents in subsequent polymerization reactions, such as affecting catalyst activity or polymer purity, and also prevents particle agglomeration caused by residual solvents during catalyst storage, ensuring long-term product stability.

[0040] This disclosure also provides a catalyst prepared using the method described above for increasing the bulk density of a catalyst, wherein the bulk density of the catalyst is ≥0.35 g / cm³. 3 The catalyst has a specific surface area of ​​202 m². 2 / g~280m 2 / g. Its high bulk density indicates that the particles are packed more densely, which helps to improve the reactor loading efficiency in the subsequent polymerization process, while the moderate specific surface area range ensures that the catalyst has sufficient active sites and avoids particle agglomeration caused by excessive specific surface area.

[0041] In summary, the apparatus, method, and catalyst for improving catalyst bulk density in this disclosure employ a combination of a conical bottom and a ribbon agitator, combined with a composite process of low-temperature vacuum drying and pulse backflushing. This approach achieves gradient solvent removal and optimized particle structure while maintaining the active sites of the catalyst. The catalyst prepared by this method exhibits high bulk density and suitable specific surface area, which helps to improve reaction efficiency and enhance the flowability of polymer powder during subsequent polymerization processes.

[0042] Example 1 This embodiment provides a method for increasing the bulk density of a catalyst, using the apparatus disclosed herein for increasing the bulk density of a catalyst, wherein the volume of the drying vessel used is 0.65 m³. 3 Four solvent filters, each 150 mm in diameter with a 15 μm pore size. The process includes the following steps: The first step involved placing 400L of catalyst-hexane slurry with a solid content of 10% into a drying reactor, and filtering it by opening the bottom filter under a pressure of 0.15MPa for 1.5 hours, during which a total of 360L of hexane was recovered. The second step is to turn on the stirrer and control the speed to 15 rpm, start the liquid ring vacuum pump to maintain the system vacuum at 40 kPa, and at the same time control the temperature inside the vessel to 45 ± 2 ℃ through the heating system to carry out the first stage of drying, which lasts for 6 hours.

[0043] The third step involves using hot nitrogen gas at 40-50℃ to perform pulse-style backflushing of the filter cake in the drying vessel through four filters for 5 minutes.

[0044] Fourth, restart the vacuum pump and perform the second stage of vacuum drying under the same temperature conditions for 2 hours.

[0045] The fifth step is to confirm that the hexane content is 10 ppm by checking the exhaust port, at which point the drying process is complete.

[0046] Example 2 The temperature inside the drying kettle is controlled at 50±2℃, and the remaining steps are the same as in Example 1.

[0047] Example 3 The temperature inside the drying kettle was controlled at 55±2℃, and the remaining steps were the same as in Example 1.

[0048] Example 4 The temperature inside the drying kettle was controlled at 50±2℃, and the first drying time was controlled at 5 hours. The remaining steps were the same as in Example 1.

[0049] Example 5 The temperature inside the drying vessel was controlled at 50±2℃, the vacuum degree was controlled at 60kpa, the first drying time was controlled at 5 hours, and the remaining steps were the same as in Example 1.

[0050] Example 6 The temperature inside the drying vessel was controlled at 55±2℃, and the vacuum degree was controlled at 60kpa. The remaining steps were the same as in Example 4.

[0051] Comparative Example 1 The temperature inside the drying vessel was controlled at 70±2℃, and the vacuum degree was controlled at 80kpa. The remaining steps were the same as in Example 1.

[0052] Comparative Example 2 The temperature inside the drying kettle was controlled at 80±2℃, and the first drying time was controlled at 4 hours. The remaining steps were the same as those in Comparative Example 1.

[0053] Comparative Example 3 The temperature inside the drying vessel was controlled at 80±2℃, the vacuum degree was atmospheric pressure (about 101kPa), the first drying time was controlled at 8 hours, and the remaining steps were the same as in Example 4.

[0054] Comparative Example 4 The difference from Example 1 is that the third step of backflushing is not performed.

[0055] The bulk density and specific surface area of ​​the catalysts in the above embodiments and comparative examples were measured using the following methods: The bulk density of the catalyst was determined in a glove box using the ASTM-D-1895 method.

[0056] The specific surface area of ​​the catalyst was determined using a Micrometer Analyzer.

[0057] Table 1 shows the bulk density and specific surface area data of the catalysts of Examples 1 to 6 and Comparative Examples 1 to 4 of this disclosure, as shown in Table 1 below: Table 1

[0058] As can be seen from the above, the low-temperature reduced-pressure drying combined with pulse backflushing process described in this disclosure can effectively improve the bulk density of the catalyst while maintaining a suitable specific surface area. In Examples 1 to 6, under drying temperatures of 45℃~55℃ and vacuum conditions of 40kPa~60kPa, the bulk density of the catalyst all reached 0.36 g / cm³. 3 The above, and the specific surface area remains at 280m². 2 Below / g. In contrast, Comparative Examples 1 to 3, using higher temperatures (≥65℃), higher vacuum levels (≥80kPa), or atmospheric pressure conditions, showed significantly lower catalyst bulk density and significantly increased specific surface area. Comparative Example 4, without pulse backflushing, had a catalyst bulk density of 0.32 g / cm³. 3 The specific surface area is 311.0791 m². 2 / g. Compared with Example 1, which has the same process conditions but includes a backflushing step, its bulk density is significantly reduced and its specific surface area is increased. This indicates that the pulse backflushing operation helps to break down the pores and agglomerates in the filter cake, promotes more uniform and efficient removal of solvent, and thus more effectively maintains the tight packing between particles during the drying process, increasing the bulk density, while avoiding over-drying that would lead to an increase in specific surface area.

[0059] Therefore, the process conditions provided in this disclosure can effectively maintain the pore structure of the catalyst and prevent particle melting, thereby achieving an increase in bulk density.

[0060] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0061] The block diagrams of devices, apparatuses, devices, and apparatuses involved in this disclosure are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and apparatuses can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0062] Additionally, as used herein, the "or" used in a list of items beginning with "at least one" indicates a separate list, such that a list of, for example, "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word "exemplary" does not imply that the described example is preferred or better than other examples.

[0063] It should also be noted that in the apparatus and method of this disclosure, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions to this disclosure.

[0064] Various changes, substitutions, and modifications can be made to the technology described herein without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, events, means, methods, and actions described above. Currently existing or later-developed processes, machines, manufactures, events, means, methods, or actions that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Therefore, the appended claims include such processes, machines, manufactures, events, means, methods, or actions within their scope.

[0065] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0066] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. An apparatus for increasing the bulk density of a catalyst, characterized in that, include: The apparatus comprises a drying vessel, a heating jacket, a stirrer, multiple solvent filters, a vacuum unit, and a backflushing unit. The heating jacket is disposed on the outer wall of the drying vessel. The stirrer extends into the internal cavity of the drying vessel. The multiple solvent filters are disposed at the bottom of the drying vessel and communicate with the internal cavity of the drying vessel. The multiple solvent filters are evenly distributed along the circumference of the drying vessel. The vacuum unit communicates with the internal cavity of the drying vessel. The backflushing unit is communicated with each of the multiple solvent filters.

2. The apparatus for increasing the bulk density of a catalyst according to claim 1, characterized in that, The bottom of the drying kettle is configured as a converging structure for concentrating materials, and the bottom of the agitator is provided with a stirring head that matches the converging structure of the drying kettle.

3. The apparatus for increasing the bulk density of a catalyst according to claim 2, characterized in that, The stirring head has an angle with the horizontal direction, the angle being 45°~75°, and the distance between the outer edge of the stirrer and the inner wall of the drying kettle is 2mm~5mm.

4. The apparatus for increasing the bulk density of a catalyst according to claim 1, characterized in that, The pore size of each solvent filter is 10μm to 40μm, and the diameter of each solvent filter is 100mm to 250mm.

5. The apparatus for increasing the bulk density of a catalyst according to any one of claims 1 to 4, characterized in that, The length-to-diameter ratio of the drying vessel is 1:1 to 1:

2.

6. A method for increasing the bulk density of a catalyst, characterized in that, The apparatus for increasing the bulk density of a catalyst according to any one of claims 1 to 5, wherein the method for increasing the bulk density of the catalyst comprises the following steps: Step 201: The slurry containing the catalyst and solvent is fed into a drying kettle and filtered through multiple solvent filters to form a catalyst filter cake; Step 202: Under the stirring action of the stirrer, turn on the heating jacket and vacuum unit, and dry the catalyst filter cake at a temperature below the boiling point of the solvent and under reduced pressure. Step 203: Use the backflushing unit to introduce backflushing medium into the solvent filter to backflush the catalyst filter cake; Step 204: Repeat steps 202 and 203 until the solvent residue of the catalyst is less than 10 ppm.

7. The method for increasing the bulk density of a catalyst according to claim 6, characterized in that, In step 202, the stirring speed of the stirrer is 5 rpm to 20 rpm, the drying temperature in the drying kettle is 40℃ to 60℃, the pressure in the drying kettle is 30 kPa to 80 kPa, and the drying time is 4 hours to 10 hours.

8. The method for increasing the bulk density of a catalyst according to claim 6, characterized in that, The backflushing medium in step 203 is nitrogen gas heated to 40°C~50°C, and the backflushing pressure is 0.1MPa~0.3MPa.

9. The method for increasing the bulk density of a catalyst according to claim 6, characterized in that, The catalyst content in the slurry is 10wt%~20wt%, and the solvent is hexane or heptane.

10. A catalyst, characterized in that, The catalyst is prepared according to any one of claims 6 to 9, wherein the bulk density of the catalyst is ≥0.35 g / cm³. 3 The catalyst has a specific surface area of ​​202 m². 2 / g~280m 2 / g.

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