Expansion tube sheet structure of a molten salt heat exchanger

Abstract

The present invention provides an expansion tube sheet structure for a molten salt heat exchanger, which can reduce the influence caused by the thermal expansion of the heat exchange tube bundle and effectively extend the service life of the molten salt heat exchanger. It includes a first tube sheet and a second tube sheet respectively located at both ends of the molten salt heat exchanger. A plurality of first tube boxes are installed on the first tube sheet. After passing through the first tube sheet, the heat exchange tubes are communicated with the first tube boxes. It is characterized in that: the second tube sheet is composed of multiple connecting blocks, the connecting blocks are connected to the ends of the heat exchange tubes, and after passing through the connecting blocks, the heat exchange tubes are communicated with the second tube boxes installed on the connecting blocks, and relative movement can occur between adjacent connecting blocks.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and specifically to a telescopic tube sheet structure of a molten salt heat exchanger. Background Art

[0002] Molten salt heat exchangers are often used in the petrochemical production process. Since the medium used in the heat exchange tubes is molten salt, they can participate in heat exchange in a high-temperature environment above 500 degrees Celsius.

[0003] An existing molten salt heat exchanger, such as a new type of molten salt heat exchanger disclosed in the patent with the publication number CN214747367U, includes a heat exchanger tube bundle, a tube sheet, and several horizontally arranged tube boxes. The heat exchanger tube bundle passes through the tube sheet and is connected to the tube boxes. The heat exchanger tube bundle can be supported by an intermediate partition. The heat exchanger tube bundle is filled with the heat exchange medium molten salt. The rear part of the tube sheet is in the shell-side process gas (process gas) to enable the vertically flowing heat exchange gas to directly contact the heat exchanger tube bundle to achieve heat exchange.

[0004] Due to the high working environment temperature of the molten salt heat exchanger, the temperature difference between the heat exchanger tube bundle in the non-working state and the heat exchanger tube bundle in the working state is large. The heat exchanger tube bundle will expand due to heat and its size will change. At the same time, due to the large volume of the heat exchanger, the heat exchanger tube bundle is heated unevenly when successively contacting the heat exchange gas in the vertical direction, resulting in different degrees of expansion of the heat exchanger tube bundle in the vertical direction. If the heat exchanger tube bundle is fixedly installed in the heat exchanger, it will affect the service life of the heat exchanger. Summary of the Invention

[0005] Aiming at the problem that the heat exchanger tube bundle of the heat exchanger will expand due to heat and affect the use of the heat exchanger, the present invention provides a telescopic tube sheet structure of a molten salt heat exchanger, which can reduce the influence caused by the thermal expansion of the heat exchanger tube bundle and effectively extend the service life of the molten salt heat exchanger.

[0006] Its technical solution is as follows: A telescopic tube sheet structure of a molten salt heat exchanger, which includes a first tube sheet and a second tube sheet respectively located at both ends of the molten salt heat exchanger. A plurality of first tube boxes are installed on the first tube sheet. The heat exchange tubes pass through the first tube sheet and are connected to the first tube boxes. It is characterized in that: the second tube sheet is composed of a plurality of connecting blocks, the connecting blocks are connected to the ends of the heat exchange tubes, the heat exchange tubes pass through the connecting blocks and are connected to the second tube boxes installed on the connecting blocks, and adjacent connecting blocks can move relative to each other.

[0007] Further, the first tube sheet includes a molten salt inlet tube sheet, a molten salt outlet tube sheet, and a first return tube sheet. The molten salt inlet tube sheet is provided with a molten salt inlet and is connected to a group of heat exchange tube bundles with the same flow direction. The molten salt outlet tube sheet is provided with a molten salt outlet and is connected to a group of heat exchange tube bundles with the same flow direction. The first return tube sheet and the second tube sheet are respectively used to connect adjacent heat exchange tube bundles with different flow directions.

[0008] Further, each of the connecting blocks is installed with a horizontally arranged second tube sheet, and each second tube sheet is used to connect two groups of heat exchange tube bundles with different flow directions up and down.

[0009] Further, the end of the heat exchange tube is connected to the second tube plate by welding.

[0010] Further, when the heat exchanger is working, the heat exchange tube bundles and the second tube plate are both located in the process gas of the shell side.

[0011] Beneficial effects: When the heat exchange tubes expand due to heat, since the second tube plate is composed of multiple connecting blocks, relative movement can occur between the connecting blocks, enabling each group of heat exchange tube bundles to freely expand and contract at the second tube plate, thereby reducing or even completely eliminating the influence of the heat-induced expansion of the heat exchange tube bundles in the axial direction of the tube bundles, effectively extending the service life of the molten salt heat exchanger. Description of the Drawings

[0012] Figure 1 is a schematic structural diagram of the molten salt heat exchanger;

[0013] Figure 2 is a schematic structural diagram of the first tube plate and the corresponding components;

[0014] Figure 3 is a schematic structural diagram of the second tube plate and the corresponding components;

[0015] Figure 4 is a schematic structural diagram of the connecting blocks during heat-induced expansion;

[0016] Figure 5 is a schematic connection diagram of the heat exchange tubes and the tube plates. Detailed Embodiment

[0017] A telescopic tube plate structure of a molten salt heat exchanger as Figure 1 shown, in combination with Figure 2 、 Figure 3As shown in the figure, it includes a first tube sheet 1 and a second tube sheet 2 respectively located at both ends of the molten salt heat exchanger. A plurality of first tube boxes 3 are installed on the first tube sheet 1. After the heat exchange tubes 4 pass through the first tube sheet 1, they are connected to the first tube boxes 3. The second tube sheet 2 is composed of a plurality of connecting blocks 5. The connecting blocks 5 are connected to the ends of the heat exchange tubes 4. After the heat exchange tubes 4 pass through the connecting blocks 5, they are connected to the second tube boxes 6 installed on the connecting blocks 5. Relative movement can occur between adjacent connecting blocks 5.

[0018] With such a design, relative movement can occur between the connecting blocks 5 along with the expansion of the heat exchange tubes to achieve the expansion and contraction of the tube sheet. As the connecting blocks 5 extend, the influence brought by thermal expansion can be offset. The following will be combined with Figure 4 For example: During the heat exchange process, since the uppermost part contacts the gas to be heated first, the temperature of the heat exchange medium in the uppermost second tube box and the corresponding heat exchange tubes is the highest, such as 500 degrees Celsius. The temperature of the heat exchange medium in the second tube box and the corresponding heat exchange tubes below is slightly lower, which is 480 degrees Celsius. The temperature of the heat exchange medium in the third tube box and the corresponding heat exchange tubes is further reduced to 450 degrees Celsius. The temperature of the heat exchange medium in the fourth tube box and the corresponding heat exchange tubes is 430 degrees Celsius. Therefore, the expansion degrees of the heat exchange tubes corresponding to each tube box are inconsistent due to different temperatures, resulting in Figure 4 As shown in the figure, there is a 2mm drop between adjacent connecting blocks. In addition, it should be mentioned that when designing the dimensions, it is necessary to ensure that the connecting blocks have a certain thickness to avoid the connecting blocks from disengaging and not being able to reset. The heat exchanger tube bundle can be supported by the middle support plate 10 (the partition plate mentioned in the background technology); when the molten salt heat exchanger is working, the heat exchange tube bundle and the second tube sheet 2 are both located in the shell-side process gas environment. Only the right part of the first tube sheet 1 is located outside for connection with the molten salt inlet and outlet pipes. Therefore, it is necessary to set heat exchange tubes 9 between the first tube boxes 3 to prevent the molten salt located outside from solidifying due to condensation.

[0019] The first tube box 3 includes a molten salt inlet tube box 3-1, a molten salt outlet tube box 3-2, and a first return tube box 3-3. The molten salt inlet tube box 3-1 is provided with a molten salt inlet 7 and is connected to a group of heat exchange tube bundles with the same flow direction. The molten salt outlet tube box 3-2 is provided with a molten salt outlet 8 and is connected to a group of heat exchange tube bundles with the same flow direction. The remaining first return tube box 3-3 and the second tube box 6 are respectively used to connect adjacent heat exchange tube bundles with different flow directions. Combining Figure 2 、 Figure 3 with the arrow directions in the figure, the flow direction of the molten salt in the tube side of the heat exchanger is as follows: First, it enters the molten salt inlet tube box 3-1 through the molten salt inlet 7 and enters a group of heat exchange tube bundles with the same flow direction until it passes through the second tube sheet 2 and enters the second tube box 6 to change the direction and enter another group of heat exchange tube bundles with the opposite flow direction. Then, it flows into the first return tube box 3-3 and enters the heat exchange tube bundles with the opposite flow direction again. The above process is repeated until it flows to the molten salt outlet tube box 3-2 and flows out from the molten salt outlet 8.

[0020] In this solution, each connecting block 5 is equipped with a laterally arranged second tube sheet 6. Each second tube sheet 6 is used to connect two sets of heat exchange tube bundles with different flow directions up and down. Multiple tube sheets can also be connected to one connecting block as needed. For example, one tube sheet in this solution can be replaced by multiple tube sheets horizontally, or multiple tube sheets can be arranged vertically at the same time (the temperature difference change of the heat exchange tube bundles with close positions vertically is small), thereby reducing the number of connecting blocks. The above designs are all covered by the protection scope of this solution.

[0021] Further, as Figure 5 shown, the end of the heat exchange tube 4 can be connected to the second tube plate 2 by welding, and the welding point is at B in the figure.

[0022] The above is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those familiar with the technology within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A telescopic tube sheet structure of a molten salt heat exchanger, which includes a first tube sheet and a second tube sheet respectively located at both ends of the molten salt heat exchanger. A plurality of first tube boxes are installed on the first tube sheet, and heat exchange tubes pass through the first tube sheet and are communicated with the first tube boxes. It is characterized in that: The second tube sheet is composed of a plurality of connecting blocks, the connecting blocks are connected to the ends of the heat exchange tubes, the heat exchange tubes pass through the connecting blocks and then communicate with a second tube box installed on the connecting blocks, and relative movement can occur between adjacent connecting blocks; The first tube box includes a molten salt inlet tube box, a molten salt outlet tube box and a first return tube box. The molten salt inlet tube box is provided with a molten salt inlet and communicates with a group of heat exchange tube bundles with the same flow direction. The molten salt outlet tube box is provided with a molten salt outlet and communicates with a group of heat exchange tube bundles with the same flow direction. The first return tube box and the second tube box are respectively used to communicate adjacent heat exchange tube bundles with different flow directions; The ends of the heat exchange tubes are connected to the second tube sheet by welding.

2. The telescopic tube sheet structure of a molten salt heat exchanger according to claim 1, characterized in that: Each connecting block is provided with a horizontally arranged second tube box, and each second tube box is used to communicate two groups of heat exchange tube bundles with different flow directions up and down.

3. The telescopic tube sheet structure of a molten salt heat exchanger according to any one of claims 1-2, characterized in that: When the heat exchanger is working, the heat exchange tube bundles and the second tube sheet are both located in the shell-side process gas.

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