Heat exchange medium flow structure of a para-xylene condenser

Abstract

The application provides a heat exchange medium flow structure of a xylene condenser, which provides a large-volume heat exchange shell, improves the gas-liquid phase replacement space of the shell side, and divides and collects the gas phase medium and the liquid phase medium at the outlet of the tube side, thereby ensuring subsequent reuse. The application relates to a heat exchange cylinder, which is horizontally arranged, and the length direction middle part of the heat exchange cylinder is provided with an upper convex gas cavity; a first tube box, which is a tube side inlet tube box and comprises an upper large-diameter inlet; a second tube box, which is a tube side outlet tube box and comprises an upper gas phase outlet and a lower liquid phase outlet; a tube bundle; and two end tube plates; the length direction two ends of the heat exchange cylinder are respectively connected with the tube plates and the corresponding connecting flanges of the two groups of tube boxes through fastening connecting pieces; the upper large-diameter inlet of the first tube box is connected with high-temperature tube side medium; and the heat exchange cylinder is arranged with the tube bundle in the whole surface area corresponding to the tube plate, and the two ends of each tube bundle are respectively inserted into the corresponding connecting interfaces of the tube plate.

Description

Technical Field

[0001] This invention relates to the technical field of paraxylene production equipment, specifically to the heat exchange medium flow structure of a paraxylene condenser. Background Technology

[0002] In the production of para-xylene, multiple operations are required to finally extract the corresponding substance. During this process, the intermediate product gas-liquid mixture needs to be purified by heat exchange to reliably separate the gas and liquid in the gas-liquid mixture for subsequent operations.

[0003] Existing paraxylene condensers (condensers for paraxylene production) generally adopt a horizontal cylindrical tank structure. They use heat exchange tubes to exchange heat between the high-temperature medium and the gas-liquid mixture in the shell side. The gas after heat exchange is located in the upper space of the horizontal cylindrical tank and is then directly output to the corresponding gas storage device through the exhaust port. The high-temperature medium in the tube side becomes a low-temperature medium after heat exchange and is directly discharged.

[0004] In existing paraxylene condensers, the high-temperature medium used for tube-side heat exchange mixes with the gas-liquid mixture in the shell side, generating both gaseous and liquid phases. However, existing paraxylene condensers have only one tube-side outlet, making it impossible to reliably distinguish and collect the two phases. Consequently, the gaseous medium, which could otherwise be reused, cannot be directly reused. Furthermore, since the gas and liquid in the shell side are placed in the upper and lower layers of a horizontal cylindrical tank, a gas cavity needs to be reserved. This means that the heat exchange tubes cannot completely fill the vertical space of the horizontal cylindrical tank, resulting in low heat exchange efficiency. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a heat exchange medium flow structure for a paraxylene condenser. This structure provides a large-volume heat exchange shell, which increases the gas-liquid phase replacement space in the shell side. Furthermore, it separates and collects the gas and liquid phase media at the tube side outlet, ensuring that they can be reused subsequently.

[0006] The heat exchange medium flow structure of a p-xylene condenser is characterized by comprising: A heat exchange cylinder, which is arranged horizontally, has an upwardly convex air cavity in the middle of its length direction; The first tube box is a tube-side feed tube box, which includes an upper large-diameter feed inlet; The second tube box is a tube-side discharge tube box, which includes an upper gas phase outlet and a lower liquid phase outlet; Tubes; and the tube sheets at both ends; The heat exchange cylinder is connected to the tube sheet and the corresponding connecting flanges of the two sets of tube boxes at both ends of its length direction by fastening connectors. The high-temperature tube medium is introduced into the upper large-diameter inlet of the first tube box. The heat exchange cylinder is arranged with tube bundles in the entire area corresponding to the tube sheet, and the two ends of each tube bundle are respectively inserted into the corresponding interface of the tube sheet.

[0007] Its further features are: The heat exchange cylinder is provided with shell-side feed inlets on both sides of the middle region of the tube bundle region in the height direction. The shell-side feed inlets are arranged close to the first tube box. The heat exchange cylinder is provided with shell-side liquid phase outlets on both sides of the middle region of the tube bundle region in the height direction. The shell-side liquid phase outlets are arranged close to the second tube box. This ensures that the shell-side gas-liquid mixture in the heat exchange cylinder is kept at a relatively high level. The second tube box is equipped with vertically arranged baffles. The baffles are arranged behind the tube sheet and are fixedly installed in the middle and upper regions of the second tube box. The baffles guide the tube-side medium flowing out of the tube bundle downwards. In this way, the baffles can prevent the tube-side medium after heat exchange from directly scouring the end cap of the second tube box and reduce the flow rate of the tube-side medium after heat exchange. After the baffles are guided, the heavy components flow out from the lower liquid phase outlet and the light components flow out from the upper gas phase outlet. This separates the heat exchange medium in the shell side into gas and liquid phases. The gas phase medium can be reused directly, while the liquid phase medium needs to be reheated to form a gas phase medium before it can be used. The heat exchange cylinder has a structure that gradually slopes upward from one end of the second tube box to one end of the first tube box, with an inclination of 1° to 2° relative to the horizontal plane. When the heat exchange cylinder is arranged at an inclination, an expansion joint is installed on the docking port of the heat exchange cylinder corresponding to the second tube box. A low saddle and a high saddle are respectively provided at both ends of the bottom length direction of the heat exchange cylinder. The high saddle is arranged close to the first tube box, and the low saddle is arranged close to the second tube box. The setting of the expansion joint allows the inclination of the heat exchange cylinder to be quickly adjusted, making assembly simple and quick. The heat exchange cylinder is equipped with several level gauges and thermometers. Due to the large heat exchange volume in the shell side, the multiple sets of level gauges and thermometers ensure that the tube side medium can meet the process requirements during the heat exchange process. When the tube side medium fails to meet the process requirements, the input of the tube side medium is adjusted to coordinate the process.

[0008] With this invention, the high-temperature tube-side medium enters the first tube box through the upper large-diameter inlet, and then exchanges heat with the shell-side medium located in the heat exchange cylinder through the annular tube bundle. Since the heat exchange cylinder includes an upward-convex cylinder, the tube bundle can be arranged within the height space corresponding to the tube sheet, which improves the gas-liquid phase replacement space of the shell side. In addition, after the tube-side medium enters the second tube box through the tube bundle, it is diverted according to the state of the tube-side medium. The liquid flows out from the lower liquid phase outlet and the gas flows out from the upper gas phase outlet. At the same time, the gas phase medium and liquid phase medium at the tube-side outlet are diverted and collected to ensure that they can be reused later. Attached Figure Description

[0009] Figure 1 This is a simplified schematic diagram of the main view structure of the present invention; The names corresponding to the serial numbers in the diagram are as follows: Heat exchanger body 10, shell-side feed inlet 101, shell-side liquid phase outlet 102, upper convex gas chamber 11, expansion joint 12, low saddle 13, high saddle 14, first tube box 20, upper large-diameter feed inlet 21, second tube box 30, upper gas phase outlet 31, lower liquid phase outlet 32, guide plate 33, tube bundle 40, tube sheet 50, fastening connector 60. Detailed Implementation

[0010] The heat exchange medium flow structure of the PX condenser is shown below. Figure 1 It includes a heat exchange cylinder 10, a first tube box 20, a second tube box 30, a tube bundle 40, and tube sheets 50 at both ends; The heat exchanger shell 10 is arranged horizontally, and an upward convex air chamber 11 is provided in the middle of the length direction of the heat exchanger shell 10; in specific implementation, the upward convex air chamber 11 is a truncated cone structure or a cylindrical structure, which can ensure that the gas in the shell side can be smoothly discharged upward. The first tube box 20 is a tube-side feed tube box, which includes an upper large-diameter feed port 21; The second tube box 30 is a tube-side discharge tube box, which includes an upper gas phase outlet 31 and a lower liquid phase outlet 32. The heat exchange cylinder 10 is connected to the tube sheet 50 and the corresponding connecting flanges of the first tube box 20 and the second tube box 30 at both ends of its length direction through fastening connectors 60. The high-temperature tube side medium is introduced into the large-diameter inlet 21 at the top of the first tube box 20. The heat exchange cylinder 10 is arranged with tube bundles 40 in the entire area corresponding to the tube sheet 50. The two ends of each tube bundle 40 are respectively inserted into the corresponding interface of the tube sheet 50.

[0011] In a specific embodiment, the heat exchange cylinder 10 is provided with shell-side feed inlets 101 on both sides of the middle region of the tube bundle region in the height direction. The shell-side feed inlets 101 are arranged close to the first tube box 20. The heat exchange cylinder 10 is provided with shell-side liquid phase outlets 102 on both sides of the middle region of the tube bundle region in the height direction. The shell-side liquid phase outlets 102 are arranged close to the second tube box 30, which makes the shell-side gas-liquid mixture in the heat exchange cylinder 10 maintain a relatively high level. A vertically arranged guide plate 33 is provided inside the second tube box 30. The guide plate 33 is arranged behind the tube sheet 50 connected to the second tube box 30. The guide plate 33 is fixedly installed in the middle and upper regions of the second tube box 30. The guide plate 33 guides the tube-side medium flowing out of the tube bundle 40 downward. In this way, the guide plate 33 can prevent the tube-side medium after heat exchange from directly scouring the end cap of the second tube box 30 and can reduce the flow rate of the tube-side medium after heat exchange. After the flow is guided, the heavy components flow out from the lower liquid phase outlet 32, and the light components flow out from the upper gas phase outlet 31. This separates the heat exchange medium in the shell side into a gas phase and a liquid phase. The gas phase medium can be reused directly, while the liquid phase medium needs to be reheated to form a gas phase medium before it can be used.

[0012] In a specific embodiment, the heat exchange cylinder 10 has a structure that gradually tilts upward from one end of the second tube box 30 to one end of the first tube box 20, and its inclination relative to the horizontal plane is 1° to 2°. When the heat exchanger body 10 is arranged at an incline, an expansion joint 12 is installed on the docking port of the heat exchanger body corresponding to the second tube box 30. A low saddle 13 and a high saddle 14 are respectively set at both ends of the bottom length direction of the heat exchanger body 10. The high saddle 14 is arranged closer to the first tube box 20, and the low saddle 13 is arranged closer to the second tube box 30. The setting of the expansion joint 12 allows the inclination of the heat exchanger body 10 to be quickly adjusted, making assembly simple and quick. The use of the expansion joint 12 reduces the thermal stress generated by the tube side and shell side under different operating temperatures and different linear expansion coefficients of materials, so that the deformation of the tube sheet and the heat exchange tubes is coordinated. Moreover, the shell side feed inlet is on the first tube box side, and the equipment is tilted downward towards the second tube box side, which allows the liquid phase to quickly pass through the support plate to the right shell side under the action of gravity.

[0013] Several level gauges and thermometers are arranged on the heat exchange cylinder 10. Due to the large heat exchange volume in the shell side, the setting of multiple level gauges and thermometers ensures that the tube side medium can meet the process requirements during the heat exchange process. When the tube side medium fails to meet the process requirements, the input of the tube side medium is adjusted to coordinate.

[0014] Its working principle is as follows: The hot tube-side medium enters the first tube box through the large-diameter inlet at the top, and then exchanges heat with the shell-side medium located in the heat exchange cylinder through the annular tube bundle. Since the heat exchange cylinder includes an upward-convex cylinder, the tube bundle can be arranged in the height space corresponding to the tube sheet, which improves the gas-liquid phase replacement space of the shell side. In addition, after the tube-side medium enters the second tube box through the tube bundle, it is guided downward by the guide plate. Then, it is split according to the state of the tube-side medium. The liquid flows out from the lower liquid phase outlet and the gas flows out from the upper gas phase outlet.

[0015] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0016] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. The heat exchange medium flow structure of a p-xylene condenser, characterized in that, It includes: A heat exchange cylinder, which is arranged horizontally, has an upwardly convex air cavity in the middle of its length direction; The first tube box is a tube-side feed tube box, which includes an upper large-diameter feed inlet; The second tube box is a tube-side discharge tube box, which includes an upper gas phase outlet and a lower liquid phase outlet; Tubes; and the tube sheets at both ends; The heat exchange cylinder is connected to the tube sheet and the corresponding connecting flanges of the two sets of tube boxes at both ends of its length direction by fastening connectors. The high-temperature tube medium is introduced into the upper large-diameter inlet of the first tube box. The heat exchange cylinder is arranged with tube bundles in the entire area corresponding to the tube sheet, and the two ends of each tube bundle are respectively inserted into the corresponding interface of the tube sheet.

2. The heat exchange medium flow structure of the p-xylene condenser according to claim 1, characterized in that: The heat exchange cylinder has shell-side feed inlets on both sides of the central region in the height direction corresponding to the tube bundle region. The shell-side feed inlets are located close to the first tube box. The heat exchange cylinder has shell-side liquid phase outlets on both sides of the central region in the height direction corresponding to the tube bundle region. The shell-side liquid phase outlets are located close to the second tube box.

3. The heat exchange medium flow structure of the p-xylene condenser according to claim 1, characterized in that: The second tube box is equipped with vertically arranged guide plates, which are located behind the tube sheet and are fixedly installed in the middle and upper regions of the second tube box.

4. The heat exchange medium flow structure of the p-xylene condenser according to claim 1, characterized in that: The heat exchange cylinder has a structure that gradually slopes upward from one end of the second tube box to the other end of the first tube box, with an inclination of 1° to 2° relative to the horizontal plane.

5. The heat exchange medium flow structure of the p-xylene condenser according to claim 4, characterized in that: When the heat exchange cylinder is arranged at an incline, an expansion joint is installed on the docking port of the heat exchange cylinder corresponding to the second tube box. A low saddle and a high saddle are respectively provided at both ends of the bottom length direction of the heat exchange cylinder. The high saddle is arranged close to the first tube box, and the low saddle is arranged close to the second tube box.

6. The heat exchange medium flow structure of the p-xylene condenser according to claim 1, characterized in that: The heat exchange cylinder is equipped with several level gauges and thermometers.

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