A novel anti-pipe-sheet cracking slurry steam generator and its processing method

Abstract

This invention relates to the field of heat exchange equipment technology, and more particularly to a novel anti-cracking slurry steam generator, comprising a fixed tube sheet and a floating tube sheet. Several spacer tubes are fixedly connected between the fixed and floating tube sheets, and a full support plate is slidably connected through each of the spacer tubes. A slide rail is installed at the bottom of the full support plate. Tube sheet holes are formed inside both the fixed and floating tube sheets, and heat exchange tubes are installed inside these holes. Liners are installed on the outside of the tube sheet holes, extending into the heat exchange tubes. A stress relief groove is formed on the outside of each tube sheet hole. This invention combines internal welding, strength expansion, lining, and stress-reducing grooves to connect the tube sheet and heat exchange tubes, effectively eliminating stress concentration points at the weld root, releasing residual welding stress, reducing corrosion in the velocity abrupt change zone, and effectively coping with the harsh stress corrosion conditions of slurry steam generators.

Description

Technical Field

[0001] This invention relates to the field of heat exchange equipment technology, and in particular to a novel anti-pipe-sheet cracking oil slurry steam generator and its processing method. Background Technology

[0002] Oil slurry steam generators for chemical cracking are key equipment in the petrochemical industry. Their core function is to efficiently recover the waste heat of high-temperature oil slurry and convert it into usable energy, while optimizing the unit's operating efficiency. They play a crucial role in improving the quality of the unit's output and reducing its energy consumption. Through efficient heat exchange between shell-side steam and tube-side oil slurry, not only is the high-temperature oil slurry cooled, but medium-pressure steam is also generated in the process, providing stable energy support for industrial production. The waste heat of the oil slurry is transferred to the feedwater to generate medium-pressure steam. This process both reduces the oil slurry temperature to meet the requirements of subsequent processes and recovers heat energy for power generation or to drive the steam turbine, reducing the unit's overall energy consumption by 5%-8%.

[0003] Traditional oil slurry steam generators operate in high-temperature and high-pressure environments with huge internal and external temperature differences. Under the action of welding residual stress, high-temperature expansion pull-out force, and torsional stress caused by the huge internal and external temperature difference of the tube sheet, circumferential and longitudinal cracks of the tube head weld and tube bridge are common, leading to leakage. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art by proposing a novel anti-pipe-sheet cracking oil slurry steam generator and its processing method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a novel anti-tube sheet cracking slurry steam generator, comprising a fixed tube sheet and a floating tube sheet, wherein several spacer tubes are fixedly connected between the fixed tube sheet and the floating tube sheet, and several full support plates are slidably connected through the spacer tubes, and slide rails are slidably connected to the bottom of the full support plates. Tube sheet holes are opened inside the fixed tube sheet and the floating tube sheet, and several heat exchange tubes are installed inside the tube sheet holes of the fixed tube sheet and the floating tube sheet. The tube openings of the heat exchange tubes are recessed inward, and liner tubes are installed on the outside of the tube sheet holes of the fixed tube sheet and the floating tube sheet. The liner tubes extend into the heat exchange tubes, and the part of the liner tube extending out of the tube sheet hole is welded to the tube sheet. Stress relief grooves are opened on the outside of each tube sheet hole, and tube sheet insulation plates are installed on the outside of both the fixed tube sheet and the floating tube sheet.

[0006] In the above-mentioned novel anti-pipe-sheet cracking slurry steam generator, both the fixed tube sheet and the floating tube sheet are circular tube sheets, and several of the spaced tubes are parallel to each other and arranged in an array with the center of the fixed tube sheet as the center.

[0007] In the above-mentioned novel anti-pipe plate cracking oil slurry steam generator, the slide is fixed on the ground or on an external bearing base to provide support, and the bottom of the full support plate has a notch that is slidably connected to the slide.

[0008] In the above-mentioned novel anti-tube sheet cracking oil slurry steam generator, the tube sheet holes of the fixed tube sheet and the floating tube sheet are positioned correspondingly, and several tube sheet holes are distributed in an array, divided into several different regions. The tube sheet holes are positioned correspondingly to the heat exchange tubes and are fitted with a clearance.

[0009] In the above-mentioned novel anti-tube sheet cracking oil slurry steam generator, several heat exchange tubes are arranged in parallel, and the outer side of the portion of the heat exchange tubes that extends into the tube sheet hole is fixedly connected with a strength expansion, which is snapped into the side wall of the tube sheet hole.

[0010] In the aforementioned novel anti-tube sheet cracking slurry steam generator, the outer portion of the tube sheet holes has a reduced pore size and an inclined gap. The inclined gap is coated with a high-temperature sulfate adhesive, which strengthens the connection between the heat exchange tube inlet and the tube sheet hole.

[0011] In the aforementioned novel anti-pipe-sheet cracking slurry steam generator, the stress relief groove has a depth of 6mm and a rounded chamfer on the inner side to avoid stress singularities.

[0012] In the above-mentioned novel anti-pipe-sheet cracking slurry steam generator, several tube-sheet insulation plates of different specifications are fixed on the outside of the fixed tube sheet and the floating tube sheet. The tube-sheet insulation plates of different specifications are fixed by several mounting nuts. The tube-sheet insulation plates of different specifications are respectively opened with insulation plate holes, and the insulation plate holes correspond to the tube-sheet holes.

[0013] In the above-mentioned novel anti-pipe plate cracking oil slurry steam generator, several lugs are welded to the outside of the fixed pipe plate, and the lugs are arranged in an array with the center of the fixed pipe plate as the center.

[0014] In the aforementioned novel anti-pipe-sheet cracking slurry steam generator, the processing method of the novel anti-pipe-sheet cracking slurry steam generator includes the following steps:

[0015] S1: The slide is fixed to a suitable working platform. Several full support plates are slidably connected on the slide. Several arrayed fixed-distance tubes pass through the full support plates to form a preliminary frame.

[0016] S2: Several tube sheet holes are opened on both the circular fixed tube sheet and the floating tube sheet. The heat exchange tubes are installed through the entire support plate. The two ends of the heat exchange tubes are inserted into the tube sheet holes respectively. Before welding, they are cleaned. Then, a strength expansion patch without lubricant is used to ensure that the heat exchange tubes are aligned with the tube sheet holes.

[0017] S3: The heat exchange tube end is about 20-100mm away from the outer surface of the tube sheet. The tube sheet hole at the end of the heat exchange tube has a welding space, which is filled with high-temperature sulfate adhesive. The heat exchange tube is preheated before welding to the tube sheet to ensure that the weld is embedded in the tube sheet hole. After welding, heat treatment is performed to relieve stress.

[0018] S4: Located in the inlet and outlet areas of the fixed tube sheet and floating tube sheet, the heat exchange tubes are fitted with a liner to ensure that there is an annular space between the liner and the heat exchange tubes. Stress relief grooves with a depth of about mm are opened on the tube sheet surface around each tube sheet hole and rounded corners are made.

[0019] S5: Install the tube sheet insulation plate on the outside of the fixed tube sheet and floating tube sheet using mounting nuts. The holes in the insulation plate correspond to the holes in the tube sheet, which not only limits the position of the liner tubes but also adds a robust external protection layer to the outer surface of the tube sheet.

[0020] Compared with existing technologies, the advantages of this invention are:

[0021] 1. The tube sheet and heat exchange tube of this invention are connected by internal hole welding, strength expansion, lining tube and stress relief groove, which avoids weld protrusion, effectively eliminates stress concentration points at the weld root, releases residual welding stress, reduces corrosion in the flow velocity change zone, and improves service life. It is suitable for high temperature difference conditions, equipment with frequent start and stop, corrosive media and high pressure systems, and is sufficient to cope with the severe stress corrosion conditions of oil slurry steam generators.

[0022] 2. This invention eliminates the factors that cause leakage due to cracking, eliminates the risk of leakage, improves fatigue life, effectively enhances equipment safety, and avoids huge losses caused by frequent equipment shutdowns and maintenance due to cracks and leaks in pipe bridges and pipe head welds, thus generating significant social and economic benefits. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of a novel anti-pipe-sheet cracking oil slurry steam generator proposed in this invention;

[0024] Figure 2 This is a schematic diagram of the structure of a novel anti-pipe-sheet cracking slurry steam generator proposed in this invention from another perspective;

[0025] Figure 3 This is a schematic diagram of the front structure of a novel anti-pipe-sheet cracking slurry steam generator proposed in this invention.

[0026] Figure 4 This is a schematic diagram of the fixed tube sheet portion of a novel anti-pipe sheet cracking oil slurry steam generator proposed in this invention;

[0027] Figure 5 for Figure 4Enlarged structural diagram of section A;

[0028] Figure 6 for Figure 5 Enlarged structural diagram of section B;

[0029] Figure 7 for Figure 5 Enlarged structural diagram of section C;

[0030] Figure 8 This is a process flow diagram of a novel anti-pipe-sheet cracking oil slurry steam generator processing method proposed in this invention.

[0031] In the diagram: 1. Fixed tube sheet; 2. Spacing tube; 3. Full support plate; 4. Floating tube sheet; 5. Tube sheet insulation plate; 6. Insulation plate hole; 7. Heat exchange tube; 8. Tube sheet hole; 9. High-temperature sulfate adhesive; 10. Liner; 11. Slide rail; 12. Support lug; 13. Mounting nut; 14. Stress relief groove; 15. Strength expansion joint. Detailed Implementation

[0032] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] Example

[0034] Reference Figure 1-4 A novel anti-cracking slurry steam generator and its manufacturing method are disclosed. The generator includes a fixed tube sheet 1 and a floating tube sheet 4. Several spacer tubes 2 are fixedly connected between the fixed tube sheet 1 and the floating tube sheet 4. A full support plate 3 is slidably connected through the spacer tubes 2. The full support plate 3 can be freely adjusted by moving along the bottom slide rail 11. Tube sheet holes 8 are provided inside both the fixed tube sheet 1 and the floating tube sheet 4 for installing heat exchange tubes 7. The heat exchange tubes 7 penetrate the full support plate 3. Liners 10 are installed outside the tube sheet holes 8 of both the fixed tube sheet 1 and the floating tube sheet 4. The liner 10 extends into the heat exchange tube 7. As an intermediate layer, the liner 10 allows for a smooth transition in stiffness between the tube sheet and the heat exchange tube 7, avoiding stress concentration caused by sudden changes in stiffness and improving the tensile and bending resistance of the orifice. The portion of the liner 10 extending out of the tube sheet hole 8 is welded to the tube sheet. Each tube sheet hole 8 has a stress relief groove 14 on its outer side. The stress relief groove allows for minor local deformation, while the stress in the inner hole weld is evenly distributed because it is completely wrapped by the tube sheet. Tube sheet insulation plates 5 are installed on the outer side of both the fixed tube sheet 1 and the floating tube sheet 4 for further port protection.

[0035] Reference Figure 5-7Rust and oil stains are removed from the tube sheet hole 8 and the end of the heat exchange tube 7 within a range of twice the tube thickness. Then, the outer side of the end of the tube sheet hole 8 is slightly expanded and flared without lubricant by strength expansion 15. The heat exchange tube 7 is then fixedly snapped into the tube sheet hole 8. Strength expansion 15 can effectively eliminate gap corrosion between the heat exchange tube 7 and the tube sheet hole 8, reduce the risk of leakage, and ensure that the heat exchange tube 7 and the tube sheet hole 8 are aligned. The end of the heat exchange tube 7 is recessed into the tube sheet by about 20-100mm. The end of the heat exchange tube 7 in the tube sheet hole 8 is left with welding space, which is filled with high-temperature sulfate adhesive 9.

[0036] Stress relief grooves 14 with rounded chamfers and a depth of about 6 mm are opened on the surface of the tube sheet around the tube sheet hole 8. Even if microcracks are generated during operation, the presence of stress relief grooves 14 prevents them from spreading to adjacent tube holes or the tube sheet body.

[0037] Reference Figure 8 The processing method of this novel anti-pipe-sheet cracking slurry steam generator includes the following steps:

[0038] S1: The slide rail 11 is fixed to a suitable working platform. Several full support plates 3 are slidably connected on the slide rail 11. Several arrayed fixed-distance tubes 2 pass through the full support plates 3 to form a preliminary frame.

[0039] S2: Several tube sheet holes 8 are opened on both the circular fixed tube sheet 1 and the floating tube sheet 4. The heat exchange tube 7 is installed through the support plate 3. The two ends of the heat exchange tube 7 are inserted into the tube sheet holes 8 respectively. Before welding, the tubes are cleaned. Then, a strength expansion 15 without lubricant is used to ensure that the heat exchange tube 7 is aligned with the tube sheet holes 8.

[0040] S3: The heat exchange tube 7 port is about 20-100mm away from the outer surface of the tube sheet. The tube sheet hole 8 at the end of the heat exchange tube 7 has a welding space, which is filled with high-temperature sulfate adhesive 9. The heat exchange tube 7 is preheated before welding to the tube sheet to ensure that the weld is embedded in the tube sheet hole 8. After welding, heat treatment is performed to eliminate stress.

[0041] S4: Located in the inlet and outlet areas of the fixed tube sheet 1 and the floating tube sheet 4, the heat exchange tube 7 is fitted with a liner 10 to ensure that there is an annular space between the liner 10 and the heat exchange tube 7. A stress relief groove 14 with a depth of about 6mm is opened on the tube sheet surface around each tube sheet hole 8 and the corners are rounded.

[0042] S5: Install the tube sheet insulation plate 5 on the outside of the fixed tube sheet 1 and the floating tube sheet 4 by installing the mounting nut 13. The position of the insulation plate hole 6 corresponds to the position of the tube sheet hole 8, which not only limits the position of the liner tube 10, but also adds a layer of robust external protection to the outer surface of the tube sheet.

[0043] In this invention, the slide 11 is fixed to a suitable working platform to ensure that it is placed horizontally as much as possible. Then, several full support plates 3 are slidably connected on the slide 11. The full support plates 3 can only move along the direction of the slide 11 and the spacing can be freely adjusted. Several arrayed fixed-distance tubes 2 are passed through the full support plates 3.

[0044] Both the circular fixed tube sheet 1 and the floating tube sheet 4 have several tube sheet holes 8. The internal dimensions of the tube sheet holes 8 are specially designed, with the diameter of the tube sheet hole 8 on the outer side being reduced. Several arrayed heat exchange tubes 7 pass through the gap of the spaced tubes 2 of the full support plate 3. The position of the heat exchange tubes 7 corresponds to the position of the tube sheet holes 8. The two ends of the heat exchange tubes 7 are inserted into the tube sheet holes 8 respectively, and the heat exchange tubes 7 and the outer periphery of the tube sheet holes 8 are fitted with a clearance.

[0045] Rust and oil stains were removed from the welding surface of the tube sheet hole 8 and the end of the heat exchange tube 7 within a range of twice the tube thickness. Before welding, the heat exchange tube 7 was fixed in the tube sheet hole 8 by light expansion without lubricant or by light flaring with a punch with a cone angle of 60°. The heat exchange tube 7 was aligned with the tube sheet hole 8. The end of the heat exchange tube 7 was about 20-100mm away from the outer surface of the tube sheet. Welding space was left at the end of the tube sheet hole 8 of the heat exchange tube 7 and filled with high-temperature sulfate adhesive 9. The heat exchange tube 7 was preheated to 100℃ before welding to the tube sheet. During welding, a small current was used for rapid welding at 150℃. Welding was done symmetrically from the center line of the tube sheet to the periphery to minimize welding deformation and residual stress. Welding was done in two passes, and the second pass must be a filler wire weld. The arc starting point should avoid the arc starting point and arc ending point of the first pass. Welding should be done by automatic argon arc welding. Post-weld heat treatment was performed to relieve stress at a temperature of 615℃ ± 15℃ for more than 2 hours.

[0046] If the manufacturer has sufficient experience and measures to ensure that the heat exchange tubes do not undergo severe deformation during heat treatment, the heat treatment should preferably be carried out by the whole tube bundle, including the tube sheet and a certain length of heat exchange tubes 7, being placed into the furnace for heat treatment. The portion outside the furnace, within at least 2000 mm, must be insulated. If a tracked electric heater is used to heat treat the tube heads, the entire tube sheet and at least 700 mm of the tube bundle should be insulated during heat treatment, with an insulation thickness of at least 100 mm. Appropriate tooling should be provided to ensure that all effective heating parts of the electric heater can be tightly fitted to the tube sheet, with no areas not in contact. At least two thermocouples should be arranged in each quadrant of the heat exchange tubes 7 to monitor the heat treatment insulation temperature, and at least one thermocouple should be installed on the tube sheet heated by the heater in each power circuit. The value measured by any thermocouple must not exceed the specified heat treatment temperature range.

[0047] The weld is embedded inside the tube sheet, avoiding direct exposure to the impact of hot and cold media. There is no weld on the end face of the tube sheet, and the welded joint is wrapped by the tube sheet material, forming a three-dimensional constraint. This eliminates surface stress concentration points, enhances tensile strength, and avoids thermal fatigue of the end face weld. Direct impact avoids stress concentration in the heat-affected zone of the tube sheet surface, thus solving the problem of cracking and failure of the tube bridge caused by the end face weld in traditional welding.

[0048] Located in the inlet and outlet areas of the tube sheet, the heat exchange tube 7 is fitted with a liner 10. There is an annular space between the liner 10 and the heat exchange tube 7. The annular space forms an air layer or a stagnant fluid layer, which can effectively reduce the direct heat conduction between the root of the heat exchange tube and the tube sheet, and reduce the risk of local overheating and deformation of the tube sheet. The liner 10 increases the metal thickness in the weak orifice area of ​​the tube sheet, which is equivalent to forming a reinforcing ring at the edge of the orifice, protecting the root of the heat exchange tube 7 from high-speed erosion by the medium. Especially on the side of the high temperature and high pressure hot medium, long-term use can effectively extend the service life of the heat exchange tube 7.

[0049] Stress relief grooves 14 with rounded chamfers and a depth of about 6 mm are opened on the surface of the tube sheet around each tube sheet hole 8. The stress relief grooves 14 concentrate the stress in a local small area instead of spreading along the entire tube sheet. When thermal expansion and contraction occur, the stress relief grooves 14 provide a small deformation space and reduce rigid constraints. The rounded chamfers inside the stress relief grooves 14 can eliminate sharp edges and avoid stress singularities.

[0050] The tube sheet insulation plate 5 is installed on the outside of the fixed tube sheet 1 and the floating tube sheet 4 by mounting nuts 13. The position of the insulation plate hole 6 corresponds to the position of the tube sheet hole 8, which not only limits the position of the liner tube 10, but also adds a layer of robust external protection to the outer surface of the tube sheet.

[0051] This invention achieves graded protection through three lines of defense: the outermost liner 10 is responsible for heat insulation and cooling and for dispersing impact; the middle stress relief groove 14 limits stress and prevents crack propagation through local deformation; and the innermost tube sheet hole 8 inner hole weld structure forms three-dimensional constraints and deep anchoring inside the tube sheet.

[0052] During the rapid heating phase of system startup, the liner 10 first absorbs thermal shock and slows down heat transfer, making the temperature gradient at the root of the heat exchange tube tend to be gentle. After entering steady-state operation, the liner establishes a stable temperature field distribution, the stress relief groove continuously dissipates the initial assembly stress, and the inner hole weld mainly bears the uniform tensile stress.

[0053] When the system is shut down and cooled, the layers of the structure respond in concert to the temperature difference and contract. The groove structure effectively avoids the accumulation of contraction stress concentration, ensuring that the weld interface is not directly damaged by surface tensile stress, thereby guaranteeing the sealing and durability of the overall connection.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A novel anti-tube sheet cracking slurry steam generator, comprising a fixed tube sheet (1) and a floating tube sheet (4), characterized in that, Several spacer tubes (2) are fixedly connected to the fixed tube sheet (1) and the floating tube sheet (4). Several full support plates (3) are slidably connected through the spacer tubes (2). Slide rails (11) are slidably connected to the bottom of the full support plates (3). Tube sheet holes (8) are opened inside both the fixed tube sheet (1) and the floating tube sheet (4). Several heat exchange tubes (7) are installed inside the tube sheet holes (8) of the fixed tube sheet (1) and the floating tube sheet (4). The heat exchange tube (7) has its opening recessed inward. A liner (10) is installed on the outside of the tube plate hole (8) of the fixed tube plate (1) and the floating tube plate (4). The liner (10) extends into the heat exchange tube (7). The part of the liner (10) extending out of the tube plate hole (8) is welded to the tube plate. A stress relief groove (14) is opened on the outside of each tube plate hole (8). A tube plate heat insulation plate (5) is installed on the outside of the fixed tube plate (1) and the floating tube plate (4).

2. The novel anti-pipe-sheet cracking slurry steam generator according to claim 1, characterized in that, Both the fixed tube sheet (1) and the floating tube sheet (4) are circular tube sheets. Several of the fixed-distance tubes (2) are parallel to each other and are arranged in an array with the center of the fixed tube sheet (1) as the center.

3. A novel anti-pipe-sheet cracking slurry steam generator according to claim 2, characterized in that, The slide (11) is fixed on the ground or on an external support base to provide support. The bottom of the full support plate (3) has a notch and the notch is slidably connected to the slide (11).

4. A novel anti-pipe-sheet cracking slurry steam generator according to claim 3, characterized in that, The tube sheet holes (8) of the fixed tube sheet (1) and the floating tube sheet (4) are in corresponding positions. Several tube sheet holes (8) are arranged in an array and divided into several different regions. The tube sheet holes (8) are in corresponding positions with the heat exchange tubes (7) and are fitted with a gap.

5. A novel anti-pipe-sheet cracking slurry steam generator according to claim 4, characterized in that, Several heat exchange tubes (7) are arranged in parallel. The heat exchange tubes (7) are fixedly connected to the outer side of the portion of the tube sheet hole (8) that extends into the tube sheet hole (8). The strength expansion (15) is snapped into the side wall of the tube sheet hole (8).

6. A novel anti-pipe-sheet cracking slurry steam generator according to claim 5, characterized in that, The tube sheet hole (8) has a smaller pore size and an inclined gap on the outer side. The inclined gap is coated with a high-temperature sulfate adhesive (9), which strengthens the connection between the heat exchange tube (7) opening and the tube sheet hole (8).

7. A novel anti-pipe-sheet cracking slurry steam generator according to claim 6, characterized in that, The stress relief groove (14) has a depth of 6 mm and the inner side of the stress relief groove (14) is rounded to avoid stress singularities.

8. A novel anti-pipe-sheet cracking slurry steam generator according to claim 7, characterized in that, Several tube sheet insulation plates (5) of different specifications are fixed on the outside of the fixed tube sheet (1) and the floating tube sheet (4). The several tube sheet insulation plates (5) of different specifications are fixed by several mounting nuts (13). The several tube sheet insulation plates (5) of different specifications are respectively opened with insulation plate holes (6). The insulation plate holes (6) correspond to the tube sheet holes (8).

9. A novel anti-pipe-sheet cracking slurry steam generator according to claim 8, characterized in that, Several lugs (12) are welded to the outside of the fixed tube sheet (1), and the lugs (12) are arranged in an array with the center of the fixed tube sheet (1) as the center.

10. A novel anti-pipe-sheet cracking slurry steam generator according to claim 9, characterized in that, The processing method of this novel anti-pipe-sheet cracking slurry steam generator includes the following steps: S1: The slide (11) is fixed to a suitable working platform. Several full support plates (3) are slidably connected on the slide (11). Several arrayed fixed-distance tubes (2) pass through the full support plates (3) to form a preliminary frame. S2: Several tube sheet holes (8) are opened on both the circular fixed tube sheet (1) and the floating tube sheet (4). Heat exchange tubes (7) are installed through the full support plate (3). The two ends of the heat exchange tubes (7) are inserted into the tube sheet holes (8) respectively. Before welding, they are cleaned. Then, a strength expansion (15) without lubricant is used to ensure that the heat exchange tubes (7) are aligned with the tube sheet holes (8). S3: The heat exchange tube (7) is about 20 to 100 mm away from the outer surface of the tube sheet. The tube sheet hole (8) at the end of the heat exchange tube (7) has a welding space and is filled with high-temperature sulfate adhesive (9). The heat exchange tube (7) is preheated before welding to the tube sheet to ensure that the weld is embedded in the tube sheet hole (8). After welding, heat treatment is performed to eliminate stress. S4: Located in the inlet and outlet areas of the fixed tube sheet (1) and the floating tube sheet (4), the heat exchange tube (7) is fitted with a liner (10) to ensure that there is an annular space between the liner (10) and the heat exchange tube (7). A stress relief groove (14) with a depth of about 6 mm is opened on the tube sheet surface around each tube sheet hole (8) and rounded corners are made. S5: Install the tube sheet insulation plate (5) on the outside of the fixed tube sheet (1) and the floating tube sheet (4) by installing nuts (13). The position of the insulation plate hole (6) corresponds to the position of the tube sheet hole (8), which not only limits the position of the liner (10), but also adds a layer of robust external protection to the outer surface of the tube sheet.

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