Inner cylinder combined catalyst support structure for large etherification reactor

Abstract

The utility model belongs to chemical equipment technical field, concretely relates to the inner tube combined type catalyst support structure for large -scale etherification reactor. Including inner tube body, inner / outer grid, inner / outer support beam, inner / outer support ring. Inner tube body is located on lower head, extends to the lowermost section catalyst bed layer lower portion. Inner support ring is fixed on the inner wall of inner tube body, and outer support ring is fixed on the outer wall of inner tube body and the inner wall of reactor cylinder body respectively, and is same height with corresponding inner support ring. The both ends of inner support beam are supported on the inner wall of inner tube body, and the both ends of outer support beam are supported on the outer wall of inner tube body and the inner wall of reactor cylinder body. The upper surface of inner and outer support beam is flush with corresponding support ring respectively, and inner and outer grid is laid on corresponding support ring and support beam respectively. Adopting inner tube combined type support structure, can make reactor cylinder body height drop significantly, and material flow is more smooth, reduces the use of porcelain ball simultaneously, and saves the cost.

Description

Technical Field

[0001] This utility model belongs to the field of chemical equipment technology, specifically relating to an inner cylinder combined catalyst support structure for large etherification reactors. Background Technology

[0002] In the MTBE production process in the chemical industry, downflow axial fixed-bed reactors are traditionally used. In such reactors, isobutylene and methanol react in a liquid phase environment of 70-100℃ with the aid of a strong acid cation exchange resin catalyst to produce MTBE. The liquid reactants enter from the top of the reactor, react through one or more catalyst beds, and the product flows out from the bottom.

[0003] For catalyst bed support in large-diameter axial reactors, a grid + support beam method has traditionally been used. In this method, the grid is made of flat steel bars and flat steel rings welded into grid blocks, which are then placed into the reactor and assembled before being placed on the support beams and support rings. The number and cross-sectional dimensions of the support beams are determined based on the catalyst loading mass and reactor diameter, through strength and stability calculations. Both ends of the support beams are placed on supports welded to the reactor shell, while the support rings are directly welded to the shell. Ultimately, the mass load and pressure drop load of the catalyst are entirely borne by the shell. However, with the increasing size of equipment and devices, the catalyst loading volume has increased, and the span of the support beams has widened, resulting in an excessive number of support beams or excessively large horizontal dimensions of the flanges, thus reducing the free flow cross-section of the material. Conversely, reducing the number of support beams and increasing the beam height would significantly increase the grid height and the shell height. These factors have made the limitations of this support method increasingly apparent.

[0004] To address the aforementioned issues, Chinese patent CN220194812U discloses a support method using an intermediate head and ceramic balls. However, this method requires additional intermediate heads, liquid collectors, and distributors, resulting in a significant increase in the height of the reactor cylinder. Furthermore, there is substantial local stress at the connection between the intermediate head and the reactor cylinder, necessitating local thickness reinforcement of the reactor cylinder. Moreover, the extensive use of supporting ceramic balls not only increases the overall load and pressure drop of the reactor but also raises procurement and maintenance costs, ultimately leading to a substantial increase in the overall investment in the reactor.

[0005] Therefore, a better support structure is urgently needed to overcome these shortcomings. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an inner cylinder combined catalyst support structure for large etherification reactors. By adopting a combined catalyst support structure of inner cylinder + inner and outer grids + inner and outer support beams, the shortcomings of traditional grid + support beam and intermediate head + ceramic ball methods are overcome, so that the support structure size is reasonable, the reactor cylinder height is significantly reduced, and the material flow is more reasonable and smooth. At the same time, the use of a large number of ceramic balls is reduced, so as to achieve the purpose of lower overall reactor investment and more energy-efficient operation.

[0007] This utility model is achieved using the following technical solution: The inner cylinder combined catalyst support structure for a large etherification reactor includes an inner cylinder, an inner grid, an outer grid, an inner support beam, an outer support beam, an inner support ring, and an outer support ring. The inner cylinder is located on the lower end cap of the reactor and extends upward to the lower part of the uppermost catalyst bed; The inner support ring is fixedly installed on the inner wall of the inner cylinder and is located at the lower part of each catalyst bed section; The outer support ring includes a portion fixed to the outer wall of the inner cylinder and a portion fixed to the inner wall of the reactor cylinder, and is located at the same height as the inner support ring of the corresponding bed layer. The lower surfaces of both the inner and outer support rings are uniformly provided with ribs to improve their load-bearing capacity. The inner and outer support rings on the inner cylinder are symmetrically arranged on both sides of the inner cylinder. By adjusting the diameter of the inner cylinder, the additional bending moment on the inner cylinder can be minimized, thus improving the overall structural stability.

[0008] The inner support beam is located inside the inner cylinder, with both ends supported by the inner wall of the inner cylinder. The outer support beam is located in the annular space between the inner cylinder and the reactor cylinder, and is evenly distributed radially, with both ends supported by the outer wall of the inner cylinder and the inner wall of the reactor cylinder. The number of outer support beams is determined based on the principle that the distance between the two outer support beams on the reactor cylinder side is similar to the diameter of the inner cylinder. Since the spans of both the inner and outer support beams are relatively short, the structural dimensions of the beams are smaller and the stability is higher when bearing the same load. By adjusting the diameter of the inner cylinder, the load borne by the inner and outer support beams can be optimized, making the beam cross-sectional dimensions more reasonable.

[0009] The upper surface of the inner support beam is flush with the upper surface of the inner support ring, and the upper surface of the outer support beam is flush with the upper surface of the outer support ring. The inner grid is laid on the inner support ring and the inner support beam; the outer grid is laid on the outer support ring and the outer support beam.

[0010] Both the inner cylinder and the reactor cylinder have manholes for the installation and removal of the grid assembly, support beams, and pipe openings, as well as the unloading of the catalyst; the manholes are reinforced with short cylindrical sections.

[0011] Both the inner and outer grids are segmented structures, and the segment sizes are configured to allow entry and exit through manholes opened on the reactor cylinder and / or the inner cylinder.

[0012] The flat steel bars of the inner grid are set perpendicular to the inner support beam; the number of circumferential blocks of the outer grid is the same as the number of outer support beams, and its flat steel bars are set along the circumferential direction, and are made of bent arc-shaped flat steel or straight flat steel.

[0013] Both the inner and outer grid blocks are covered with Johnson mesh to support the catalyst bed and allow material to pass through.

[0014] The two ends of the inner support beam are fixedly connected to the supports or stiffening plates welded to the inner wall of the inner cylinder by bolts, and the two ends of the outer support beam are fixedly connected to the supports or stiffening plates welded to the outer wall of the inner cylinder and the inner wall of the reactor cylinder by bolts.

[0015] Both the inner and outer support beams are made of I-beams or welded H-beams, and the number of inner support beams is at most one.

[0016] The inner cylinder is placed on or welded to the lower head of the reactor via a pad, which can fully utilize the load-bearing capacity of the lower head to share the mass of the catalyst bed and the pressure drop load; the connection between the inner cylinder and the lower head of the reactor is uniformly reinforced with ribs in the circumferential direction. The inner cylinder only bears compressive stress, has high rigidity and strong resistance to instability, and requires a small wall thickness.

[0017] The reactor is provided with a feed inlet and a distributor at the top and a discharge outlet at the bottom. At least two catalyst beds are arranged axially within the reactor cylinder. The upper part of each catalyst bed is filled with catalyst, and the bottom of the catalyst bed is filled with ceramic balls.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows: (1) The inner cylinder combined catalyst support structure for large etherification reactor described in this utility model adopts an inner cylinder combined catalyst support structure, which eliminates the use of unnecessary stainless steel internal parts (such as intermediate end caps, liquid collectors, distributors, etc.) and a large number of ceramic balls, so that the height of the reactor cylinder can be reduced significantly. For large etherification reactors made of stainless steel composite plates, this can significantly reduce the direct manufacturing cost of the reactor; at the same time, it reduces the procurement, replacement and maintenance costs of internal parts and ceramic balls, further reducing the overall cost of the reactor. (2) The inner cylinder combined catalyst support structure for large etherification reactor described in this utility model has rationally optimized the dimensions of its support beams and support grids, shortened the span of the inner and outer support beams, resulting in smaller structural dimensions and higher stability when bearing the same load. Furthermore, the load borne by the beams can be optimized by adjusting the diameter of the inner cylinder, making the beam cross-sectional dimensions more reasonable. This increases the free flow area of ​​the reactor cross-section. In addition, the elimination of internal components such as intermediate heads and distributors, as well as redundant ceramic balls, makes the material reaction and flow smoother, reducing fluid resistance and pressure drop. (3) The inner cylinder combined catalyst support structure for large etherification reactor described in this utility model has an inner cylinder placed or welded to the lower head of the reactor via a pad. This fully utilizes the bearing capacity of the lower head to share the mass of the catalyst bed and the pressure drop load. The inner cylinder only bears compressive stress, has high rigidity and strong resistance to instability, and the reinforcing ribs uniformly arranged circumferentially at the connection further enhance local stability. The inner and outer support rings are symmetrically arranged on both sides of the inner cylinder, and the lower surface is uniformly distributed with reinforcing ribs. This not only improves its own bearing capacity, but also minimizes the additional bending moment of the inner cylinder by adjusting the diameter of the inner cylinder, thus improving the overall stability of the structure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the inner cylinder combined catalyst support structure for a large etherification reactor described in this utility model. Figure 2 for Figure 1 A top view of the structure at point A in the middle; Figure 3 for Figure 1 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the support structure described in Comparative Example 1; In the diagram: 1. Outer grid; 2. Outer support ring; 3. Outer support beam; 4. Inner cylinder; 5. Reactor cylinder; 6. Inner grid; 7. Inner support ring; 8. Inner support beam; 9. Lower head; 10. Catalyst; 11. Catalyst bed; 12. Ceramic balls; 13. Manhole; 14. Intermediate head; 15. Liquid collector; 16. Distributor; 17. Feed inlet; 18. Discharge outlet; 19. Circulating liquid outlet. Detailed Implementation

[0020] To make the objectives and technical solutions of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0021] Example 1 like Figure 1-3As shown, the MTBE unit has a single-stage etherification reactor with a feed inlet 17 and a distributor 16 at the top, and a discharge outlet 18 and a circulating liquid outlet 19 at the bottom. The reactor cylinder 5 has a diameter of 5.4 m, and two catalyst beds 11 are arranged axially inside, each catalyst bed 11 having a height of 3.45 m. The upper part of each catalyst bed 11 is filled with catalyst 10, and the bottom of the catalyst bed 11 is filled with ceramic balls 12. The reactor adopts the inner cylinder combined catalyst support structure for large etherification reactors described in this utility model.

[0022] The inner cylinder 4 is welded to the lower head 9 of the reactor via a gasket. Reinforcing ribs are evenly distributed circumferentially at the connection between the inner cylinder 4 and the lower head 9 to enhance the local connection strength. The inner cylinder 4 has a diameter of 1.8m and a height of 8.25m, extending upwards to the lower part of the uppermost catalyst bed 11. Three manholes 13 are provided on the inner cylinder 4 from top to bottom, and short cylindrical sections are provided at the locations of the manholes 13 for local reinforcement.

[0023] On the inner wall of the inner cylinder 4, corresponding to the lower position of each catalyst bed 11, an inner support ring 7 is fixedly welded. The outer support ring 2 is divided into two parts: one part is fixedly welded to the outer wall of the inner cylinder 4, and the other part is fixedly welded to the inner wall of the reactor cylinder 5. The outer support ring 2 and the inner support ring 7 corresponding to the same catalyst bed 11 are located at the same height. The lower surfaces of both the inner support ring 7 and the outer support ring 2 are uniformly welded with stiffeners along the circumference to improve their load-bearing capacity. The inner support ring 7 and the outer support ring 2 on the inner cylinder 4 are symmetrically arranged on both sides of the inner cylinder 4.

[0024] The inner support beam 8 is located inside the inner cylinder 4, consisting of one beam made of welded H-beams. Both ends of the beam are bolted to supports welded to the inner wall of the inner cylinder 4, and the upper surface of the inner support beam 8 is flush with the upper surface of the inner support ring 7. The outer support beams 3 are located in the annular space between the inner cylinder 4 and the reactor cylinder 5, arranged radially and evenly, numbering twelve. These are also made of H-beams, and both ends are bolted to supports welded to the outer wall of the inner cylinder 4 and the inner wall of the reactor cylinder 5, respectively. The upper surface of the outer support beams 3 is flush with the upper surface of the outer support ring 2. Because both the span of the inner support beam 8 (1.8m) and the span of the outer support beam 3 (approximately 1.8m) are relatively short, the beam cross-sectional dimensions are smaller and the stability is higher when bearing the loads of the catalyst 10 and ceramic balls 12.

[0025] The inner grid 6 is laid on the inner support ring 7 and the inner support beam 8, and adopts a segmented structure, consisting of three sections. Each inner grid 6 is welded from straight flat steel bars, which are set perpendicular to the inner support beam 8. The segment size ensures that it can pass through the manhole 13 on the inner cylinder 4 and the reactor cylinder 5. The outer grid 1 is laid on the outer support ring 2 and the outer support beam 3, and also adopts a segmented structure. The number of circumferential segments is the same as the number of outer support beams 3 (twelve segments). The flat steel bars of each outer grid 1 are set circumferentially and are made of bent arc-shaped flat steel and straight flat steel, respectively. Its segment size allows it to pass through the manhole 13 on the reactor cylinder 5. Johnson mesh is laid flat on the inner and outer grids to support the catalyst 10 and ceramic balls 12 and allow material to pass through.

[0026] After adopting the above-mentioned inner cylinder combined catalyst support structure, the reactor cylinder 5 has a height of 12.61m, and the net metal mass of the reactor, including the distributor 16, support grid, and support beam assembly, is approximately 160.1 tons. The total amount of ceramic balls 12 used in the catalyst bed 11 is 20.6m. 3 .

[0027] Comparative Example 1 like Figure 4 As shown, Comparative Example 1 uses a single-stage etherification reactor of the MTBE unit with the same specifications as Example 1. The reactor has a feed inlet 17 and a distributor 16 at the top, and a discharge outlet 18 and a circulating liquid outlet 19 at the bottom. The reactor shell 5 also has a diameter of 5.4m, and two catalyst beds 11 are arranged axially inside, each catalyst bed 11 with a height of 3.45m. The upper part of each catalyst bed 11 is filled with catalyst 10, and the bottom of the catalyst bed 11 is filled with ceramic balls 12. The catalyst bed 11 of this reactor is supported by an "intermediate head 14 + ceramic balls 12" structure.

[0028] The support structure mainly consists of an intermediate end cap 14, a liquid collector 15, a distributor 16, and a large number of ceramic balls 12, as detailed below: To support the upper catalyst bed 11, an intermediate end cap 14 is welded and fixed inside the reactor shell 5, below the upper catalyst bed 11. The end cap 14 is filled with supporting ceramic balls 12 and has a dish-shaped structure, with its edges welded to the inner wall of the reactor shell 5. Because the intermediate end cap 14 must bear the entire mass load of the upper catalyst bed 11 (including the catalyst 10 and ceramic balls 12) and the material pressure drop, there is significant local stress at the connection point. Therefore, the corresponding connection area of ​​the reactor shell 5 needs to be locally reinforced—the local shell wall thickness is increased from 30mm to 36mm.

[0029] A liquid collector 15 is installed inside the intermediate head 14. The liquid collector 15 adopts an open cylindrical section structure and is wrapped with wire mesh to isolate ceramic balls. It is used to collect the reaction material flowing out of the upper catalyst bed 11. Below the intermediate head 14 and the liquid collector 15, a distributor 16 is installed. The distributor 16 has a central and branch pipe distribution structure. The end of the distribution pipe is placed on the support of the reactor body 5. It is used to evenly distribute the material collected by the liquid collector 15 to the lower catalyst bed 11 to ensure reaction uniformity.

[0030] A liquid collector 15 is provided above the discharge port on the lower head 9. Supporting ceramic balls 12 are filled in the space between the lower head 9 and the lower catalyst bed 11 to support the lower catalyst bed 11. A wire mesh is wrapped around the circulating liquid outlet 19 in this space to prevent the ceramic balls from entering the distribution pipe through the openings on the distribution pipe of the circulating liquid outlet 19.

[0031] With the above-mentioned "intermediate head 14 + ceramic balls 12" structure, the reactor body 5 needs to be increased to 14.6m in height due to the inclusion of the intermediate head 14, the collector 15, and the distributor 16; the net metal mass of the reactor, including the distributor 16, the intermediate head 14, and the collector 15, is approximately 175 tons; the normal usage of ceramic balls 12 in the two catalyst beds 11 is 20.6m. 3 The total amount of 12 newly added ceramic balls for filling and support reached 83.1m. 3 This not only increased the equipment procurement cost, but also increased the reactor operating pressure drop compared to Example 1, and significantly increased long-term operating energy consumption and the cost of replacing and maintaining ceramic balls 12.

Claims

1. A combined inner cylinder catalyst support structure for a large etherification reactor, characterized in that, It includes an inner cylinder (4), an inner grid (6), an outer grid (1), an inner support beam (8), an outer support beam (3), an inner support ring (7), and an outer support ring (2); The inner cylinder (4) is set on the lower head (9) of the reactor and extends upward to the lower part of the uppermost catalyst bed (11); The inner support ring (7) is fixedly installed on the inner wall of the inner cylinder (4) and located at the lower part of each catalyst bed (11); the outer support ring (2) includes a part fixed to the outer wall of the inner cylinder (4) and a part fixed to the inner wall of the reactor cylinder (5), and is at the same height as the inner support ring (7) of the corresponding catalyst bed (11); The inner support beam (8) is located inside the inner cylinder (4), and its two ends are supported on the inner wall of the inner cylinder (4); the outer support beam (3) is located in the annular space between the inner cylinder (4) and the reactor cylinder (5), and is evenly arranged radially, with its two ends supported on the outer wall of the inner cylinder (4) and the inner wall of the reactor cylinder (5). The upper surface of the inner support beam (8) is flush with the upper surface of the inner support ring (7), and the upper surface of the outer support beam (3) is flush with the upper surface of the outer support ring (2). The inner grid (6) is laid on the inner support ring (7) and the inner support beam (8); the outer grid (1) is laid on the outer support ring (2) and the outer support beam (3).

2. The inner cylinder combined catalyst support structure for a large etherification reactor according to claim 1, characterized in that, Both the inner cylinder (4) and the reactor cylinder (5) have manholes (13).

3. The inner cylinder combined catalyst support structure for a large etherification reactor according to claim 2, characterized in that, The inner grid (6) and outer grid (1) are both segmented structures, and the segment size is configured to allow entry and exit through manholes (13) opened on the reactor cylinder (5) and / or the inner cylinder (4).

4. The inner cylinder combined catalyst support structure for a large etherification reactor according to claim 3, characterized in that, The flat steel strips of the inner grid (6) are set perpendicular to the inner support beam (8); the number of circumferential blocks of the outer grid (1) is the same as the number of outer support beams (3), and its flat steel strips are set along the circumferential direction, and are made of bent arc-shaped flat steel or straight flat steel.

5. The inner cylinder combined catalyst support structure for a large etherification reactor according to claim 1, characterized in that, The two ends of the inner support beam (8) are fixedly connected to the supports or stiffeners welded to the inner wall of the inner cylinder (4) by bolts, and the two ends of the outer support beam (3) are fixedly connected to the supports or stiffeners welded to the outer wall of the inner cylinder (4) and the inner wall of the reactor cylinder (5) by bolts.

6. The inner cylinder combined catalyst support structure for a large etherification reactor according to claim 1, characterized in that, Both the inner support beam (8) and the outer support beam (3) are made of I-beams or welded H-beams, and the number of inner support beams (8) is at most one.

7. The inner cylinder combined catalyst support structure for a large etherification reactor according to claim 1, characterized in that, The inner cylinder (4) is placed or welded to the lower head (9) of the reactor by means of a pad.

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