Feed device for large-scale fixed-bed reactor

Abstract

The application discloses a feeding device for a large-scale fixed-bed reactor with tubes, which comprises a cylinder assembly for air flow, an upper end of the cylinder assembly being provided with a feeding port, and a lower end of the cylinder assembly being provided with a discharging port; a primary filtering assembly connected below the feeding port, through which the air flow is initially filtered; a gas distributor arranged in the cylinder assembly and below the primary filtering assembly, through which the air flow is uniformly distributed; and a heat exchange pipe assembly between the gas distributor and the discharging port, through which the air flow flows to the discharging port and is discharged. The feeding device for the large-scale fixed-bed reactor with tubes can effectively filter the sundries in the air through the filtering assembly, and can uniformly distribute the air through the heat exchange pipe assembly by the gas distributor, so that terminal interception filtering and efficient air flow distribution can be simultaneously realized, and the catalytic efficiency is ensured.

Description

Technical Field

[0001] This invention relates to the field of chemical machinery, specifically to tubular fixed-bed reactors, and more particularly to a feeding device for large tubular fixed-bed reactors. Background Technology

[0002] Tubular fixed-bed reactors are among the most widely used gas-solid phase catalytic reaction equipment in chemical production, and are widely used in important processes such as hydrogenation, oxidation, and dehydrogenation. In this type of reactor, the catalyst is placed in heat exchange tubes, and the reactant gas flows from top to bottom through the tubes to react with the catalyst bed in the gas phase. The heating medium flows through the shell side to provide the heat required for the reaction.

[0003] As equipment becomes larger, the diameter of a single reactor is increasing, with the number of internal heat exchange tubes reaching thousands or even tens of thousands. This large-scale operation presents challenges for feed structure design, with existing structures exhibiting two major problems. First, the increased size leads to uneven flow field distribution and a "jet" effect. In small-scale reactors, the gas flow is relatively easy to distribute evenly due to the small tube diameter. However, in large industrial reactors, the feed inlet is typically located at the center of the head, and its diameter is much smaller than the reactor shell diameter. The high-speed incoming feed gas forms a strong central jet, resulting in a much higher gas velocity in the central region than in the peripheral region. This velocity difference leads to inconsistent residence times in the tubes. Excessive velocity in the central region results in insufficient conversion; excessively slow velocity in the peripheral region may lead to over-reaction or increased byproducts. In strongly exothermic reactions, this uneven distribution easily leads to "hot spots," severely affecting catalytic efficiency. Second, in actual long-term industrial operation, the reactant gas inevitably carries solid impurities. The sources and formation of these impurities mainly include: ① Upstream process carryover: If the upstream process involves fluidized bed or slurry bed, the feed gas often carries fine catalyst dust or adsorbent powder that has not been completely separated; ② Generation in the pipeline: Under the action of high temperature, high pressure or corrosive media, the pipe wall of long-distance metal pipelines will detach and oxidize (rust scale); In addition, large particulate impurities such as welding slag and gasket fragments left during equipment maintenance often enter the system in the early stage of operation; ③ Thermal denaturation of the material itself: Some organic raw materials may coke or thermally polymerize due to local overheating in high-temperature feed pipelines and preheaters, forming coke powder or polymer particles.

[0004] To address the aforementioned problems, existing technologies typically employ the following methods: ① External pipeline filters: A filter is installed on the feed main pipe outside the reactor. For example, patent application CN202682909U discloses a Y-type filter that intercepts solid particles through a metal mesh. While this method can intercept upstream impurities, it cannot intercept "secondary impurities" (such as rust scale detached from the pipe wall) generated downstream to the reactor inlet flange section, and it cannot solve the problem of uneven airflow distribution inside the reactor. ② Traditional distribution plates: To solve the distribution problem, existing technologies often install porous distribution plates inside the reactor. For example, patent application CN103721642A discloses a filter distribution plate for a fixed-bed reactor, combining filtration and distribution functions. However, without fine filtration, coke powder and rust scale easily clog the small holes of the distribution plate, leading to uneven airflow distribution, and the distribution plate is very difficult to disassemble and clean. Summary of the Invention

[0005] The technical problem to be solved by this invention is: in order to solve the problem of uneven gas distribution and ineffective filtration of impurities in the prior art, this invention provides a feeding device for a large-scale tubular fixed-bed reactor. The device effectively filters all impurities in the air through the filter assembly and uses a gas distributor to uniformly distribute the gas through the heat exchange tube assembly. It can simultaneously achieve terminal interception filtration and efficient gas flow uniformity, thereby ensuring catalytic efficiency.

[0006] The technical solution adopted by this invention to solve its technical problem is: a feeding device for a large-scale tubular fixed-bed reactor, comprising: A cylindrical assembly for supplying airflow, the upper end of the cylindrical assembly having a feed inlet and the lower end of the cylindrical assembly having a discharge outlet; A primary filter assembly is connected below the feed inlet, and the airflow undergoes initial filtration through the primary filter assembly. A gas distributor is located inside the cylindrical assembly and below the primary filter assembly, through which the airflow is evenly distributed; A heat exchange tube assembly is located between a gas distributor and a discharge port, and the gas flow flows along the heat exchange tube assembly to the discharge port.

[0007] This invention relates to a feeding device for a large-scale tubular fixed-bed reactor. The gas flow is filtered through a primary filter assembly at the feed inlet, removing impurities such as rust, coke powder, and catalyst dust from the raw gas before it enters the catalytic bed, ensuring gas purity. This, combined with a gas distributor, achieves uniform gas flow distribution, ensuring consistent reaction intensity and temperature across the heat exchange tube assembly and guaranteeing catalytic efficiency.

[0008] Furthermore, in order to achieve uniform airflow distribution, the gas distributor includes multiple annular distribution units, which are arranged radially from the inside out at intervals, and adjacent distribution units form a flow distribution channel for evenly distributing airflow.

[0009] Furthermore, in order to ensure that the airflow can cover all heat exchange tube assemblies, the distribution unit has a trumpet-shaped structure, with the trumpet-shaped opening facing the outlet along the axial direction, and adjacent distribution units form a multi-layered annular airflow channel.

[0010] Furthermore, in order to further optimize the airflow distribution effect, the distribution units are arranged concentrically, with the lengths of the distribution units arranged from the inside out increasing in the axial direction, and the taper of the distribution units arranged from the inside out gradually increasing.

[0011] Furthermore, in order to fully filter different impurities, the primary filtration assembly includes: Filter cartridge, the filter cartridge being installed inside the feed inlet; A coarse filter plate, which is installed at the inlet of the filter cartridge; The intermediate filter plate is installed inside the filter cylinder, and the spacing between the intermediate filter plates is set below the coarse filter plate. Fine filter plates are installed at the bottom of the filter cylinder and are spaced apart above the gas distributor.

[0012] Furthermore, in order to assemble the filter plates, a filter shell is provided inside the filter cylinder, the intermediate filter plate is installed at the bottom of the filter shell, and the coarse filter plate is installed at the top of the filter shell.

[0013] Furthermore, in order to assemble the primary filter assembly with the cylinder assembly, the filter assembly also includes a mounting plate, the filter cylinder is connected to the mounting plate, and the mounting plate is installed on top of the feed inlet.

[0014] Furthermore, in order to enable quick assembly and disassembly of the primary filter assembly, the bottom of the mounting plate is provided with an insert block, on which an elastic element is connected. The other end of the elastic element is connected to a locking block, and the insert block and locking block cooperate with the feed inlet to assemble and disassemble the mounting plate.

[0015] Furthermore, in order to further improve the filtration effect, a secondary filtration assembly is also provided inside the cylindrical assembly. The secondary filtration assembly includes a secondary filter cylinder and a secondary filter plate. The secondary filter cylinder is installed inside the cylindrical assembly, and the secondary filter plate is installed on the secondary filter cylinder. The secondary filter plate is located between the gas distributor and the heat exchange tube assembly.

[0016] Furthermore, in order to enable the heat exchanger to fully contact the gas, the heat exchange tube assembly includes a plurality of heat exchange tubes arranged axially within the cylindrical assembly and arranged circumferentially around the center circle of the cylindrical assembly.

[0017] The beneficial effects of this invention are: 1. The feeding device for a large tubular fixed-bed reactor of the present invention filters the gas through a primary filtration component to ensure the purity of the gas and prevent impurities from entering the catalytic bed. At the same time, the gas distributor is used to uniformly distribute the gas flow, which solves the problem of uneven gas distribution in the reactor and thus improves the catalytic efficiency.

[0018] 2. The feeding device for a large tubular fixed-bed reactor of the present invention utilizes a multi-layer annular gas distribution unit of a gas distributor to uniformly divide the gas flow, ensuring that the divided gas can be evenly dispersed to the inlet end face of each heat exchange tube, so that the reaction degree and temperature in all heat exchange tubes are consistent, thereby avoiding insufficient conversion rate caused by excessively fast gas flow in the central region during the reaction process, and also avoiding side reactions or over-reactions caused by excessively slow flow velocity in the edge region.

[0019] 3. The feeding device for a large tubular fixed-bed reactor of the present invention allows for quick assembly and disassembly of the primary filter assembly at the feed inlet, enabling rapid replacement or maintenance of the primary filter assembly. This avoids the accumulation of excessive impurities in the primary filter assembly, which could affect the catalytic efficiency, greatly improving the reactor's maintenance efficiency and reducing downtime.

[0020] 4. The feeding device for a large tubular fixed-bed reactor of the present invention uses a primary filter and a secondary filter assembly to optimize the filtration effect, effectively removing impurities such as rust, coke powder, and catalyst dust from the reaction raw material gas. This ensures the purity of the gas entering the reactor and prevents impurities from entering the catalytic bed, thereby guaranteeing catalytic efficiency. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the feeding device of the present invention for a large tubular fixed bed reactor.

[0023] Figure 2 yes Figure 1 A schematic diagram of the internal structure.

[0024] Figure 3 yes Figure 2 A partial structural diagram.

[0025] Figure 4 yes Figure 3A magnified schematic diagram of the structure at point B.

[0026] Figure 5 yes Figure 3 A magnified schematic diagram of the structure at point A.

[0027] Figure 6 This is a schematic diagram of the structure of Embodiment 3.

[0028] In the picture: 1. Cylinder assembly; 11. Inlet; 12. Outlet; 2. Primary filtration assembly; 21. Filter cartridge; 22. Coarse filter plate; 23. Medium filter plate; 24. Fine filter plate; 25. Filter housing; 26. Mounting plate; 27. Insert block; 28. Elastic element; 29. ​​Locking block; 3. Gas distributor; 31. Distribution unit; 32. Diversion channel; 4. Heat exchanger tube assembly; 41. Heat exchanger tube; 5. Secondary filter assembly; 51. Secondary filter cartridge; 52. Secondary filter plate. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0030] Example 1: like Figures 1 to 4 As shown, a feeding device for a large tubular fixed-bed reactor includes: a cylindrical assembly 1, a primary filter assembly 2, a gas distributor 3, and a heat exchange tube assembly 4. The upper end of the cylindrical assembly 1 has a feed inlet 11, and the lower end of the cylindrical assembly 1 has a discharge outlet 12. Gas flow enters through the feed inlet 11 and exits through the discharge outlet 12. The cylindrical assembly 1 consists of an upper cylinder, a cylindrical body, and a lower cylinder; the feed inlet 11 is located at the upper end of the upper cylinder, and the discharge outlet 12 is located at the lower end of the lower cylinder.

[0031] Specifically, the primary filter assembly 2 is connected below the feed inlet 11, and the airflow undergoes initial filtration through the primary filter assembly 2. The gas distributor 3 is located inside the cylindrical assembly and below the primary filter assembly 2, and the airflow is evenly distributed through the gas distributor 3. The heat exchange tube assembly 4 is located between the gas distributor 3 and the outlet 12, and the airflow flows along the heat exchange tube assembly 4 to the outlet 12. In this embodiment, the reactant gas enters the cylindrical assembly 1 from the top feed inlet 11. When the gas flows through the primary filter assembly 2, impurities such as particulate matter, rust, coke powder, and catalyst dust in the gas are intercepted by the primary filter assembly 2. Then, the gas enters the gas distributor 3. Under the action of the gas distributor 3, the gas flowing through the gas distributor 3 is evenly distributed radially, so that the airflow can completely cover the entire heat exchange tube assembly 4 in the radial direction. The gas flows evenly towards the end face inlet of the heat exchange tube assembly 4, ensuring that the reaction degree and temperature are consistent in all heat exchange tube assemblies 4.

[0032] Specifically, the heat exchange tube assembly 4 includes a plurality of heat exchange tubes 41, which are arranged axially within the cylindrical assembly 1 and circumferentially around the center circle of the cylindrical assembly 1. The heat exchange tubes 41 are arranged radially at intervals within the cylindrical assembly 1, and airflow flows axially from the upper end face of the heat exchange tubes 41 across the side wall of the heat exchange tubes 41.

[0033] Preferably, the gas distributor 3 includes multiple annular distribution units 31, which are arranged radially from the inside out at intervals, and adjacent distribution units 31 form a flow distribution channel 32 for evenly distributing the airflow. Due to the structural relationship between the feed inlet 11 and the upper cylinder, the airflow is difficult to diffuse radially automatically when passing through the cylinder assembly 1, which leads to inconsistent temperatures and reaction rates between the center and periphery of the heat exchange tube assembly 4. Therefore, before the airflow enters the heat exchange tube assembly 4, it passes through the gas distributor 3. Since the gas distributor 3 forms multiple flow distribution channels 32 radially from the inside out, the gas diffuses radially evenly along the flow distribution channels 32, so that the airflow can cover the entire heat exchange tube assembly 4 in the radial direction, ensuring that the overall reaction rate and temperature of the heat exchange tube assembly 4 are consistent, and improving the catalytic efficiency.

[0034] Specifically, the distribution unit 31 has a trumpet-shaped structure, with the trumpet-shaped opening facing the discharge port 12 along the axial direction. Adjacent distribution units 31 form a multi-layered annular airflow channel. Guided by the trumpet-shaped structure of the distribution unit 31, the airflow can diffuse radially as much as possible, ensuring uniform airflow distribution.

[0035] Preferably, the distribution units 31 are concentrically arranged, with their axial lengths overlapping from the inside out, and the taper of the distribution units 31 gradually increasing from the inside out. In this embodiment, the taper of the innermost distribution unit 31 is 5°, and the taper of the outermost distribution unit 31 is 45°.

[0036] In this embodiment, there are five distribution units 31. The outermost distribution unit 31 has the longest axial length on its left end, while the innermost distribution unit 31 has the longest axial length. Through the synergistic effect of the "cohesive and diffuse" cone angle gradient (gradually increasing from 5° at the innermost layer to 45° at the outermost layer) and the "long inner and short outer" axial length gradient of the distribution units, the physical reconstruction of the high-pressure gas flow at the feed inlet of the large reactor is achieved. The inner layer distribution units, with their smaller cone angle and longer axial stroke, can penetrate deep into the core of the high-pressure flow field to strongly intercept and mitigate the "central jet" effect, preventing gas from accumulating too quickly in the central region. Simultaneously, the gradually increasing cone angle and shortened axial height of the outer layer distribution units can guide the gas flow to diffuse smoothly radially using a larger slope, effectively compensating for the flow resistance caused by the increased radial span. This dual reverse gradient coupling design ensures that the feed gas achieves an absolutely uniform flow distribution throughout the entire catalytic bed, thereby ensuring that the reaction bed is maintained at the optimal reaction temperature.

[0037] Specifically, the primary filtration assembly 2 includes a filter cartridge 21. The filter cartridge 21 is installed inside the feed inlet 11. A coarse filter plate 22 is installed at the inlet of the filter cartridge 21. A medium filter plate 23 is installed inside the filter cartridge 21, with the spacing between the medium filter plates 23 below the coarse filter plate 22. A fine filter plate 24 is installed at the bottom of the filter cartridge 21, with the fine filter plates 24 spaced above the gas distributor 3. The coarse filter plate 22, medium filter plate 23, and fine filter plate 24 achieve step-by-step filtration, effectively removing residual fine particulate matter and preventing these particles from entering the bed and clogging the catalyst pores, which would lead to increased bed pressure drop and decreased reaction efficiency.

[0038] Preferably, the filter cartridge 21 contains a filter shell 25, with the intermediate filter plate 23 installed at the bottom of the filter shell 25 and the coarse filter plate 22 installed at the top of the filter shell 25. The primary filtration assembly 2 is integrally assembled onto the feed inlet 11 via the filter cartridge 21.

[0039] Example 2: Based on Example 1, such as Figure 5As shown, the filter assembly also includes a mounting plate 26, on which the filter cartridge 21 is connected. The mounting plate 26 is installed on the top of the feed inlet 11. A plug 27 is located at the bottom of the mounting plate 26, and an elastic element 28 is connected to the plug 27. The other end of the elastic element 28 is connected to a locking block 29. The plug 27 and locking block 29 cooperate with the feed inlet 11 to install and remove the mounting plate 26. The plug 27, elastic element 28, and locking block 29 allow for quick replacement of the primary filter assembly 2. After long-term use, the primary filter assembly 2 can be removed for cleaning or replaced with a new one. Simply press the locking block 29 to retract it into the cavity of the plug 27, insert the plug 27 into the feed inlet 11, and release the locking block 29. The locking block 29 rebounds under the action of the elastic element 28 (a spring can be selected) and presses against the feed inlet 11, thus fixing the mounting plate 26 to the top of the feed inlet 11.

[0040] Example 3: Based on Example 2, such as Figure 6 As shown, a secondary filter assembly 5 is also provided inside the cylinder assembly 1. The secondary filter assembly 5 includes a secondary filter cylinder 51 and a secondary filter plate 52. The secondary filter cylinder 51 is installed inside the cylinder assembly 1, and the secondary filter plate 52 is installed on the secondary filter cylinder 51. The secondary filter plate 52 is located between the gas distributor 3 and the heat exchange tube assembly 4.

[0041] The reaction feed gas first undergoes primary filtration through the primary filter assembly 2 inside the feed inlet 11 to remove most of the rust, coke powder, catalyst dust, and other particulate matter. Subsequently, the gas is initially dispersed through the annular outlet of the gas distributor 3. Before entering the heat exchange tube 41, the gas flow passes through the secondary filter plate 52 installed at the bottom of the gas distributor 3 for secondary filtration, further intercepting residual fine particulate matter. The purified gas after dispersion and secondary filtration enters each heat exchange tube 41 to participate in subsequent reactions.

[0042] The secondary filter cartridge 51 and secondary filter plate 52 perform deep filtration on the gas after the primary filtration, effectively removing residual fine particles and preventing them from entering the catalyst bed within the heat exchange tube 41, thus preventing catalyst pore blockage. This reduces the impact of particulate matter on the catalyst, further lowering the risk of increased bed pressure drop, ensuring the stability of reaction efficiency and catalytic conversion rate, and extending the catalyst's lifespan. Combined with the existing filter components, this forms a two-stage filtration system, enhancing the purification capacity of the reactant gas and providing better feedstock gas conditions for the smooth progress of the reaction.

[0043] This invention relates to a feeding device for a large-scale tubular fixed-bed reactor. It effectively filters out all impurities in the air through a filter assembly and uses a gas distributor to uniformly distribute the gas through the heat exchange tube assembly. This simultaneously achieves terminal interception filtration and efficient gas flow distribution, thereby ensuring catalytic efficiency.

[0044] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A feeding device for a large-scale tubular fixed-bed reactor, characterized in that: include: A cylindrical assembly (1) for supplying airflow has an inlet (11) at its upper end and an outlet (12) at its lower end. A primary filter assembly (2) is connected below the feed inlet (11), and the airflow is initially filtered through the primary filter assembly (2); Gas distributor (3) is located inside the cylinder assembly (1) and below the primary filter assembly (2). The airflow is evenly distributed through the gas distributor (3). The heat exchange tube assembly (4) is located between the gas distributor (3) and the outlet (12), and the airflow flows along the heat exchange tube assembly (4) to the outlet (12) and flows out.

2. The feeding device for a large-scale tubular fixed-bed reactor according to claim 1, characterized in that: The gas distributor (3) includes multiple annular distribution units (31), which are arranged radially from the inside to the outside at intervals, and a flow distribution channel for evenly distributing airflow is formed between adjacent distribution units (31).

3. The feeding device for a large-scale tubular fixed-bed reactor according to claim 2, characterized in that: The distribution unit (31) has a trumpet-shaped structure, and the trumpet-shaped opening faces the discharge port (12) axially. Adjacent distribution units (31) form a multi-layered annular airflow channel.

4. The feeding device for a large-scale tubular fixed-bed reactor according to claim 3, characterized in that: The distribution units (31) are arranged concentrically, and the lengths of the distribution units (31) arranged from the inside to the outside are intersecting in the axial direction. The taper of the distribution units (31) arranged from the inside to the outside gradually increases.

5. The feeding device for a large-scale tubular fixed-bed reactor according to claim 1, characterized in that: The primary filter component (2) includes: A filter cartridge (21) is installed inside the feed inlet (11); A coarse filter plate (22) is installed at the inlet of the filter cylinder (21); The intermediate filter plate (23) is installed inside the filter cylinder (21), and the spacing of the intermediate filter plate (23) is set below the coarse filter plate (22); Fine filter plate (24) is installed at the bottom of filter cylinder (21) and is spaced above gas distributor (3).

6. The feeding device for a large-scale tubular fixed-bed reactor according to claim 5, characterized in that: The filter cylinder (21) is provided with a filter shell (25), the intermediate filter plate (23) is installed at the bottom of the filter shell (25), and the coarse filter plate (22) is installed at the top of the filter shell (25).

7. The feeding device for a large-scale tubular fixed-bed reactor according to claim 5, characterized in that: The filter assembly also includes a mounting plate (26), on which the filter cartridge (21) is connected, and the mounting plate (26) is mounted on top of the feed inlet (11).

8. The feeding device for a large-scale tubular fixed-bed reactor according to claim 7, characterized in that: The bottom of the mounting plate (26) is provided with a plug (27), and an elastic element (28) is connected to the plug (27). The other end of the elastic element (28) is connected to a locking block (29). The plug (27) and the locking block (29) cooperate with the feed port (11) to install and remove the mounting plate (26).

9. The feeding device for a large-scale tubular fixed-bed reactor according to any one of claims 1-8, characterized in that: The cylindrical assembly (1) is further provided with a secondary filter assembly (5). The secondary filter assembly (5) includes a secondary filter cylinder (51) and a secondary filter plate (52). The secondary filter cylinder (51) is installed inside the cylindrical assembly (1), and the secondary filter plate (52) is installed on the secondary filter cylinder (51). The secondary filter plate (52) is located between the gas distributor (3) and the heat exchange tube assembly (4).

10. The feeding device for a large-scale tubular fixed-bed reactor according to claim 1, characterized in that: The heat exchange tube assembly (4) includes a plurality of heat exchange tubes (41), which are arranged axially inside the cylindrical assembly (1) and are arranged circumferentially around the center circle of the cylindrical assembly (1).

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