A sector barrel for a radial reactor

Abstract

This invention discloses a fan-shaped cylinder for a radial reactor. The back plate of the fan-shaped cylinder has openings, and the opening area, opening ratio, and opening size are defined as follows: Openings can be made along the entire length, but in practice, the main coking area is in the lower middle part. Therefore, the opening area is distributed within 2 / 3 of the height range starting from the bottom of the fan-shaped cylinder. The opening ratio can vary from bottom to top, typically around 10% of the front opening ratio. The opening shape can be circular or oblong, and the opening size is comparable to the front opening. This invention, through the application of a new structure, reduces and eliminates coking and carbon buildup caused by the presence of dead zones, as well as the possibility of both forming large coke lumps with the catalyst within the dead zones. This significantly improves the reliability of the reaction and reduces internal damage and abnormal downtime caused by coking and carbon buildup.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, specifically relating to a sector-shaped cylinder for a radial reactor. Background Technology

[0002] The sector-shaped cylinder is a key internal component of a radial reactor, commonly used in continuous reforming and isomerization processes. In catalytic reforming, after the feed gas enters the reactor through the inlet, it initially disperses to the periphery of the reactor. At this point, the sector-shaped cylinder plays a crucial role, ensuring the gas is evenly distributed from top to bottom into the catalyst bed. This allows the gas to fully contact the catalyst and undergo a chemical reaction.

[0003] In existing technologies, the sector-shaped cylinders are distributed circumferentially along the inner wall of the reactor. There are two main types of sector-shaped cylinders, as shown in the attached figures. Figure 1 and attached Figure 2 As shown. (Attached) Figure 1 The diagram shows a simplified representation of a perforated plate sector, consisting of a perforated plate 2 facing the catalyst bed and a back plate 1 backing onto the reactor wall. (See attached diagram.) Figure 2 The diagram shown is a simplified representation of a strip screen fan-shaped cylinder, consisting of V-section wires 4, support rings 3, and a back plate 1. The back plate is a non-perforated arc-shaped plate with an arc radius matching the inner diameter of the reactor. (As shown in the attached diagram...) Figure 1 Still attached Figure 2 The shown sector-shaped cylinder receives the reaction feed from the reactor inlet, which enters longitudinally into the cylinder and then radially through the perforated area (wire mesh or perforated plate) on the front of the cylinder, the catalyst bed, and finally into the central tube. A schematic diagram of the material flow through the cross-section of the sector-shaped cylinder is attached. Figure 3 The fan-shaped cylinder serves to guide and uniformly distribute the reaction feed into the catalyst bed.

[0004] Most sector-shaped cylinders are over 10 meters long. When installed inside a reactor, due to manufacturing and installation precision issues with both the reactor and the sector-shaped cylinder, a certain degree of flow dead zone exists between the reactor wall and the back plate of the sector-shaped cylinder. Figure 3 As shown, the presence of dead zones can lead to the accumulation of fine catalyst particles, which in turn induces coking and carbon buildup, causing deformation and damage to the fan-shaped cylinder, preventing the achievement of the corresponding process performance, and ultimately resulting in a shutdown event where the reaction cannot proceed normally.

[0005] The current sector-shaped cylinder has the following disadvantages:

[0006] 1. Since the sector cylinders are arranged along the circumference of the reactor shell, some dimensional allowance is left during production to avoid interference caused by dimensional deviations during the installation of internal components. Therefore, there will inevitably be a gap between the two sector cylinders, and the existence of this gap will induce coking.

[0007] 2. Due to manufacturing and installation precision issues with the reactor and sector cylinders, a gap of approximately 10mm inevitably appears between the back plate and the inner wall of the reactor shell during installation. This creates a flow dead zone, where a small amount of catalyst can become stuck. Consequently, the coke deposits formed after coking continuously increase in volume at the gap between the back plate and the two sector cylinders, causing mechanical damage to the sector cylinders. (See attached document) Figure 3 .

[0008] 3. Once coking occurs, it is difficult to remove during equipment operation. The only way to remove coking is through manual removal or replacement of internal parts during shutdown and maintenance, which affects long-term safe production. Summary of the Invention

[0009] This invention provides a sector-shaped cylinder for a radial reactor to solve the technical problem of coking in sector-shaped cylinders under high-temperature operating conditions in the prior art.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows:

[0011] A sector-shaped cylinder for a radial reactor is mainly composed of V-shaped cross-section wire, a perforated back plate, and a support ring. Its characteristic is that a vent hole is provided on the back plate of the sector-shaped cylinder body. Through the vent hole, part of the raw material gas is guided to flow out from the gap between the back plate of the sector-shaped cylinder and the inner wall of the shell, which can reduce the occurrence of coking around the sector-shaped cylinder.

[0012] The present invention provides a fan-shaped cylinder for a radial reactor, further characterized in that: the vent holes are arranged vertically or linearly at a certain angle on the back plate of the fan-shaped cylinder, with 3 to 10 holes evenly arranged in the horizontal direction and one hole arranged at intervals of 0.5m to 1.5m in the vertical direction.

[0013] The present invention provides a sector-shaped cylinder for a radial reactor, further characterized in that: the diameter of the vent hole should be slightly larger than the equivalent diameter D of the outer screen, approximately 1.5D to 3D.

[0014] The present invention provides a sector-shaped cylinder for a radial reactor, which is further characterized in that: in order to increase the opening area of ​​the vent, the vent can also be set as an oblong hole, with the diameter of the semicircles at both ends of the hole being the same as that of a single circular hole, and the length in the middle being set to 3 to 5D according to the specific structure of the sector-shaped cylinder.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. Through the opening in the back plate, material can flow out through the gap between the back plate and the inner wall of the reactor, thereby eliminating the dead flow zone in this part. Without the dead flow zone, the material will not be able to stay here, thus reducing the risk of carbon buildup.

[0017] 2. Due to the flow of materials, the accumulation of catalyst in this area is eliminated, and the probability of filamentous carbon formation caused by the catalyst is reduced accordingly. It plays an active decoking role in the operation of the continuous reforming unit and has an inhibitory effect on the initial formation of filamentous carbon.

[0018] 3. It solves the problem of insufficient catalyst utilization between sector cylinders, thereby improving the catalyst activity in this area, promoting chemical reactions, significantly improving catalyst utilization efficiency, and eliminating coking problems between sector cylinders.

[0019] 4. The application of the new structure reduces and eliminates the possibility of coking and carbon buildup caused by the presence of dead zones, as well as the formation of large coke lumps by both and the catalyst in the dead zones. This greatly improves the reliability of the reaction and reduces internal damage and abnormal shutdowns caused by coking and carbon buildup. Attached Figure Description

[0020] Appendix Figure 1 A simplified diagram of the basic structure of a perforated plate sector cylinder in the prior art;

[0021] Appendix Figure 2 A simplified diagram of the basic structure of a strip wire mesh fan-shaped cylinder in the prior art;

[0022] Appendix Figure 3 A schematic diagram of material flow and coking zone in a traditional sector-shaped cylinder in the prior art;

[0023] Appendix Figure 4 A schematic diagram of a sector-shaped cylinder opening for a radial reactor according to the present invention;

[0024] Appendix Figure 5 The present invention relates to a fan-shaped cross-section flow field for a radial reactor.

[0025] The attached figures are labeled as follows: 1-back plate, 2-perforated plate, 3-support ring, 4-V-section wire, 5-perforated back plate. Detailed Implementation

[0026] The implementation of the technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0027] To make the description of the usage method, technical solution, and features of this patent clearer and more understandable, the following description is in conjunction with the appendix. Figure 1-5 This patent will be described in more detail below.

[0028] The existing technology of sector-shaped cylinders is as follows: Figures 1-2 As shown, it includes a back plate 1, a perforated plate 2 or a V-section wire 4, and a support ring 3. After long-term operation, coking is prone to occur between the fan-shaped cylindrical back plate and the reactor shell; during the operation of the unit, the flow field distribution of its feed gas is shown in the attached figure. Figure 3As shown, the inner side is the central tube, the outer side is the reactor shell, the fan-shaped cylinders are distributed circumferentially along the inner wall of the reactor, the area between the fan-shaped cylinders is the area where the catalyst is easy to accumulate, and the gap between the back plate and the reactor shell is the flow dead zone.

[0029] To improve the process performance of the sector-shaped cylinder, this patent proposes a sector-shaped cylinder for a radial reactor, the structure of which is shown in the attached figure. Figure 4 As shown, it includes: an open back plate 5, a V-shaped cross-section wire 4, and a support ring 3. During equipment operation, the raw material gas enters the sector cylinder from the top of the sector cylinder. Under the action of pressure difference, it flows through the gap between the V-shaped wire and the open hole on the back plate (see attached diagram). Figure 4 In this process, the gas is evenly distributed from top to bottom into the catalyst bed. (This is in contrast to the previous sentence about gas distribution.) Figure 3 To address the areas prone to coking, the flow field of the fan-shaped cylinder cross-section was optimized by opening vents in the back plate, allowing a portion of the airflow to escape from the gap between the back plate and the reactor inner wall under pressure differential. (Appendix) Figure 5 The diagram shows the cross-sectional flow field of the sector-shaped cylinder of the present invention. The inner side is the central tube, and the outer side is the reactor shell. The sector-shaped cylinder is distributed circumferentially along the inner wall of the reactor. Point ① is the coking area of ​​the existing structure. By opening the back plate structure, the traditional flow field distribution of the coking-prone area is disrupted, enabling the structure to avoid coking around the sector-shaped cylinder.

[0030] The hole structure parameters of the back plate opening need to be determined according to the actual process operation conditions. Generally, the ventilation holes are required to be arranged vertically or linearly at a certain angle on the fan-shaped cylinder back plate, with 3 to 10 holes evenly arranged in the horizontal direction and one hole arranged every 0.5m to 1.5m in the vertical direction. The diameter of the ventilation hole should be slightly larger than the equivalent diameter D of the outer screen, about 1.5D to 3D.

[0031] If the circular hole cannot meet the flow field requirements according to the above rules, an oblong hole can be made on the back plate. The diameter of the semicircles at both ends of the hole is the same as that of the single circular hole, and the length in the middle is set to 3 to 5D according to the specific structure of the fan-shaped cylinder.

[0032] The above are merely typical embodiments of the present invention. It should be noted that those skilled in the art can make several improvements or substitutions without departing from the principles described in the present invention, and these improvements or substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A sector-shaped cylinder for a radial reactor, mainly composed of V-shaped cross-section wires, a perforated back plate, and a support ring, characterized in that: A vent is provided on the back plate of the sector cylinder body. Through the vent, some of the raw material gas is guided to flow out from the gap between the back plate of the sector cylinder and the inner wall of the shell, which can reduce the occurrence of coking around the sector cylinder.

2. The sector cartridge for a radial reactor of claim 1, wherein: The ventilation holes are arranged vertically or linearly at a certain angle on the back plate of the fan-shaped cylinder.

3. The sector barrel for a radial reactor of claim 1, wherein: The ventilation holes are arranged in a uniform manner in the horizontal direction (3 to 10 holes) and in the vertical direction (one hole every 0.5m to 1.5m).

4. The sector barrel for a radial reactor of claim 1, wherein: The diameter of the vent hole should be slightly larger than the equivalent diameter D of the outer screen, ranging from 1.5D to 3D.

5. The sector barrel for a radial reactor of claim 1, wherein: The vent is an oblong hole, with the diameter of the semicircles at both ends being the same as that of a single circular hole, and the length in the middle being 3 to 5D depending on the specific structure of the fan-shaped cylinder.

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