A flexible tube sheet structure and a waste heat boiler having the same

Abstract

The present invention relates to the technical field of heat exchange equipment, and specifically to a flexible tube sheet structure and a waste heat boiler having the structure, wherein the flexible tube sheet structure includes a thin tube sheet, a thick tube sheet, and a plurality of tension plates, the tension plates including a plate body and a plurality of tie rods arranged on the plate body, the thick tube sheet is provided with a plurality of arranged bosses, the plate body is butt-welded to the corresponding bosses of the thick tube sheet, the thick tube sheet and the thin tube sheet are provided with tube holes for heat exchange tubes to pass through; the thin tube sheet is provided with a plurality of rows of support holes, the plurality of tie rods of the tension plates are inserted into the corresponding rows of support holes and are countersunk welded to each other. The thin tube sheet and the thick tube sheet are welded together by tension plates, and the thick tube sheet, which is not prone to deformation, is connected to the thin tube sheet into one piece by tension plates with greater rigidity, thereby strengthening the strength of the thin tube sheet, preventing deformation of the thin tube sheet, and preventing problems such as instability of the tension plates; the arrangement and welding of the tension plates of the present invention are convenient, reducing manufacturing difficulty; the overall strength is higher, and a more effective strengthening effect is provided for the thin tube sheet.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange equipment used in the fields of petroleum refining, chemical industry, coal chemical industry, and more particularly to a flexible tube sheet structure and a waste heat boiler having the structure. Background Art

[0002] In fields such as petroleum refining and chemical engineering, coal chemical industry, and others, research on energy-saving technologies is increasing. Heat exchangers are the most widely used and widely used equipment for heat recovery. The junction between the tube sheet and the heat transfer tubes is the core and most vulnerable part of the heat exchanger. A large number of heat exchanger failures occur in this area. Waste heat boilers are a common type of heat exchanger.

[0003] Due to the thickness of traditional tubesheets, heat transfer is slow, temperature gradients are large, and stress concentration is a detrimental factor to equipment operation. This can easily damage the connection between the heat exchange tubes and the tubesheet, making it a major weak point in the heat exchanger. Excessively thick tubesheets also create excessive gaps between the tube holes and the heat exchange tubes, allowing salts to concentrate and scale in these gaps, leading to scaling corrosion. Under high-temperature conditions, thick tubesheet heat exchangers struggle to maintain long-term operation.

[0004] The use of thin tubesheets effectively reduces the temperature difference between the tubesheets, effectively preventing damage to the joints between the heat exchange tubes and the tubesheets, as well as equipment failure caused by tubesheet cracking. However, in large, high-pressure, and high-temperature environments, especially those with large pressure differences between the shell and tube, thin tubesheet waste heat boilers can experience significant deformation of the tubesheets due to the shell-to-tube pressure difference, which can easily lead to failure of the joints between the tubesheets and the heat exchange tubes.

[0005] As a result, the inventors proposed a technology with Chinese patent number CN201720412001.6, entitled "A Double-Tubesheet Combined Rapid-Cooling Boiler for Coal Chemical Industry." This technology combines thin tubesheets with thick tubesheets, which are welded together using dense reinforcement bars. The thin tubesheets can absorb some thermal expansion due to their elastic deformation, and they conduct heat well, minimizing the temperature difference between the two sides of the thin tubesheets. This reduces thermal stress on the tubesheets during operation and enhances the cooling effect. Furthermore, the reinforcement bars connect the thin tubesheets and thick tubesheets into a single unit, strengthening the thin tubesheets and making them less prone to deformation, maintaining a flat surface. This prevents the connection between the thin tubesheets and the shell from being subjected to alternating bending loads, allowing the thin tubesheets to withstand greater pressure.

[0006] As can be seen from the above, the thin tube sheet and the thick tube sheet are fixed by welding in large numbers and densely arranged, which makes welding and fixing difficult. In addition, the tie bars and the thick tube sheet are fillet welded, and the fixing strength is low. Summary of the Invention

[0007] In view of the above technical problems existing in the prior art, the present invention provides a flexible tube sheet structure and a waste heat boiler having the structure, which is easy to weld and fix and has high connection strength.

[0008] To achieve the above objectives, the present invention provides the following technical solutions:

[0009] A flexible tube sheet structure is provided, comprising a thin tube sheet and a thick tube sheet, and further comprising a plurality of tensioning plates arranged in parallel, wherein the tensioning plates comprise a plate body and a plurality of tie rods arranged on the plate body, the thick tube sheet is provided with a plurality of arranged bosses, the plate bodies of the plurality of tensioning plates are butt-welded to the bosses corresponding to the thick tube sheet, the thick tube sheet and the thin tube sheet are both provided with tube holes for passing heat exchange tubes; the thin tube sheet is provided with a plurality of rows of support holes, the plurality of tie rods of the tensioning plates are inserted into the support holes of the corresponding rows and are fixed by countersunk welding.

[0010] Further preferably, the plate body and the pull rod of each of the support plates are an integrated structure.

[0011] Further preferably, the plate body is a square plate, and the end surface of the boss is a flat surface that matches the end surface of the plate body.

[0012] Further preferably, the supporting hole is a circular hole, and the pull rod is a round rod that matches the supporting hole.

[0013] Further preferably, the plate body is provided with slots running through the thickness thereof.

[0014] Further preferably, there are multiple slots, and the multiple slots are arranged along the width and length directions of the plate.

[0015] Further preferably, the periphery of the tube hole is expanded with an extension groove, so that the tube hole is in a plum blossom shape; and / or the thick tube plate is provided with a plurality of liquid holes near its periphery.

[0016] Further preferably, the end of the pull rod is flush with the end surface of the thin tube sheet.

[0017] The waste heat boiler with the above-mentioned flexible tube sheet structure includes an inlet tube box, an outlet tube box and a shell-side cylinder. The shell-side cylinder has multiple heat exchange tubes built in. The thin tube sheet is connected to the inlet tube box, and the thick tube sheet is connected to the shell-side cylinder. One end of the heat exchange tube passes through the tube hole of the thick tube sheet, then passes through between two adjacent tension plates, and then connects to the inlet tube box through the thin tube sheet; the shell-side cylinder is also provided with a rear tube sheet, and the other end of the heat exchange tube passes through the rear tube sheet and connects to the outlet tube box.

[0018] Further preferably, the width of the plate body of the support plate is smaller than the inner diameter of the shell-side cylinder, so that a gap is left between the plate body and the shell-side cylinder.

[0019] Beneficial effects of the present invention:

[0020] Compared with the prior art, the flexible tube sheet structure and the waste heat boiler having the same have the following effects:

[0021] 1) Compared with the existing heat exchange tube and thick tube sheet connection structure, the heat exchange tube and thin tube sheet connection structure of the present invention is more likely to achieve full penetration deep hole welding, ensure the quality of the tube head, and avoid high temperature failure and crevice corrosion problems in the welds connecting the heat exchange tube and thick tube sheet;

[0022] 2) The double tube sheet structure with thin tube sheets combined with thick tube sheets can enhance the strength of the thin tube sheets and avoid the thin tube sheets from bending and deforming significantly during use, which could cause equipment failure.

[0023] 3) The double tube sheets of thin tube sheets and thick tube sheets are welded together by tension plates. The thick tube sheets that are less prone to deformation are connected to the thin tube sheets by tension plates with greater rigidity, thereby strengthening the strength of the thin tube sheets and preventing them from deformation.

[0024] 4) The connection between the brace plate and the thick tube sheet is a plate structure, which can prevent the brace plate from becoming unstable.

[0025] 5) Compared with the existing technology of densely welding multiple tie bars separately, the present invention can arrange and weld each tie plate, which facilitates the welding operation and reduces the manufacturing difficulty;

[0026] 6) Each row of tie rods is connected to each other by the plate body, which has higher overall strength and provides more effective reinforcement for the thin tube sheet;

[0027] Further:

[0028] 7) The connection between the tension plate and the thin tube sheet is a tie rod structure, while the connection with the thick tube sheet is a plate with slotted holes. This structure enables the shell-side cooling water to flow quickly and evenly between the double tube sheets, preventing high-temperature dead corners that may cause high-temperature failure of the equipment.

[0029] 8) There is a large gap between the plum blossom-shaped tube holes on the thick tube sheet and the heat exchange tubes, so that the cooling liquid can pass through the thick tube sheet without clogging and gap corrosion; the plum blossom-shaped tube holes on the thick tube sheet have plum blossom petals evenly distributed, so that the cooling liquid flows evenly;

[0030] 9) The width of the support plate is smaller than the inner diameter of the shell cylinder. A liquid flow channel is left between the shell cylinder and the support plate, so that the outer ring of the shell can also be cooled by cooling water to avoid high temperature failure;

[0031] 10) The support plate is inserted into the thin tube sheet and welded with a countersunk hole; a boss is left on the thick tube sheet to be welded with the support plate, and the thick tube sheet and the support plate are butt-welded to ensure the welding quality between the support plate and the tube sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the waste heat boiler in the embodiment.

[0033] Figure 2 It is the specific structure diagram of position I in the figure.

[0034] Figure 3 for Figure 2 Cross-sectional view along the BB direction.

[0035] Figure 4 for Figure 2 Schematic diagram of direction A.

[0036] Figure 5 for Figure 2 View from the CC direction.

[0037] Figure 6 Schematic diagram of the bracing plate in the embodiment.

[0038] Figure 7 FIG. 1 is another visual schematic diagram of the tensioning plate in the embodiment.

[0039] Figure 8 Schematic diagram of the thick tube sheet in the embodiment.

[0040] Figure 9 FIG. 1 is another visual schematic diagram of the thick tube plate in the embodiment.

[0041] Figure 10 It is another visual schematic diagram of the thick tube plate in the embodiment.

[0042] Figure 11 Schematic diagram of the tube holes of the thick tube sheet in the embodiment.

[0043] Reference numerals:

[0044] Inlet tube box 1, flexible tube sheet structure 2, shell-side cylinder 3, rear tube sheet 4, outlet tube box 5, thin tube sheet 6, support plate 7, boss 8, thick tube sheet 9, heat exchange tube 10, support hole 11, tie rod 12, plate body 13, slot hole 14, tube hole 15, liquid hole 16. DETAILED DESCRIPTION

[0045] The present invention is described in detail below with reference to specific embodiments and accompanying drawings.

[0046] The waste heat boiler of this embodiment, such as Figures 1 to 11As shown, it includes an inlet tube box 1, an outlet tube box 5, and a shell-side cylinder 3. The shell-side cylinder 3 is provided with a flexible tube sheet structure 2 at the end near the inlet tube box 1. The flexible tube sheet structure 2 includes a thin tube sheet 6, a thick tube sheet 9, and multiple bracing plates 7 arranged in parallel. Each bracing plate 7 includes a plate body 13 and multiple tie rods 12 arranged on one side of the plate body 13. The thick tube sheet 9 is provided with multiple arranged bosses 8. The bosses 8 are arranged in the same direction as the width of the plate body 13. The other side of the plate body 13 is butt-welded to the corresponding bosses 8 on the thick tube sheet 9. The thin tube sheet 6 has multiple rows of support holes 11. The multiple tie rods 12 of the bracing plate 7 are inserted into the corresponding rows of support holes 11 and are fixed by countersunk welding. They are then ground flat after welding. In practice, the tie rods 12 can only extend a small section from the plate body 13. Controlling the length of the tie rods 12 can further improve the overall strength of the bracing plate 7. The thickness of the thin tube sheet 6 and the thick tube sheet 9 are relative to each other. The thickness of the thin tube sheet 6 meets the requirement of flexible deformation, and the thickness of the thick tube sheet 9 meets the requirement of strength.

[0047] The combination of thin tubesheet 6 and thick tubesheet 9 prevents damage to the traditional heat exchange tube 10-tubesheet connection and equipment failure caused by tubesheet cracking. It also reduces the risk of significant bending and deformation of the tubesheet under high-pressure and high-temperature conditions, particularly under conditions with large pressure differences between the shell and tube sides. This structure also offers the advantage of preventing corrosion failure in the interstitial structure. The dual tubesheet structure, combining thin tubesheet 6 with thick tubesheet 9, strengthens the thin tubesheet 6 and prevents significant bending and deformation during use, which could lead to equipment failure. The thin tubesheet 6 and thick tubesheet 9 are welded together using bracing plates 7. The rigid bracing plates 7 connect the thin tubesheet 6, which is less prone to deformation, to a single unit, strengthening its strength and preventing deformation. The connecting side of the bracing plates 7 and the thick tubesheet 9 is a plate body 13, which prevents instability and other issues. Compared to existing techniques that involve closely welding multiple tie bars, the present invention requires only the alignment and welding of individual bracing plates 7. This modular welding method facilitates welding and reduces manufacturing complexity. Each row of tie rods 12 is connected to each other by a plate body 13 to form an integral body, which has a higher overall strength and provides a more effective reinforcement effect for the thin tube sheet 6.

[0048] The shell-side cylinder 3 is equipped with a plurality of heat exchange tubes 10 arranged in parallel. The thin tube sheet 6 is connected to the inlet tube box 1, and the thick tube sheet 9 is connected to the shell-side cylinder 3. Both the thin tube sheet 6 and the thick tube sheet 9 are provided with tube holes 15 for the heat exchange tubes 10 to pass through. After one end of the heat exchange tube 10 passes through the tube hole 15 of the thick tube sheet 9, it passes between two adjacent tension plates 7 and then connects to the inlet tube box 1 through the thin tube sheet 6. The fluid in the inlet tube box 1 flows into the heat exchange tube 10. The heat exchange tube 10 is welded to the thin tube sheet 6. Compared with the traditional connection structure of heat exchange tubes and thicker tube sheets, the heat exchange tube 10 and the thin tube sheet 6 of this embodiment are more easily fully welded with deep holes, ensuring the quality of the tube head. Compared with the traditional connection structure of thick tube sheet 9 and heat exchange tube 10, the fully welded deep hole structure of the thin tube sheet 6 avoids the high-temperature failure and crevice corrosion problems of the welds connecting the heat exchange tube 10 and the thick tube sheet 9. The shell-side cylinder 3 is further provided with a rear tube sheet 4 , and the other end of the heat exchange tube 10 passes through the rear tube sheet 4 and is connected to the outlet pipe box 5 .

[0049] In this embodiment, the plate body 13 and tie rods 12 of each bracing plate 7 are integrated. Specifically, grooves are cut into the plate to form multiple tie rods 12. The plate body 13 is square, and the end faces of the bosses 8 are flat surfaces that match the ends of the plate body 13, providing a larger welding area and a stronger weld. The support holes 11 are circular, and the tie rods 12 are round rods that fit into the support holes 11.

[0050] In this embodiment, the plate body 13 is provided with a plurality of elliptical slots 14 extending through the thickness thereof, and the plurality of slots 14 are arranged along the width and length of the plate body 13. This structure enables the shell-side cooling water to flow quickly and evenly between the double tube sheets, thereby preventing the formation of high-temperature dead corners that could cause high-temperature failure of the equipment.

[0051] In this embodiment, Figure 11 As shown, the perimeter of the tube hole 15 is expanded with an extended groove, giving the tube hole 15 a plum blossom shape. A large gap exists between the plum blossom-shaped tube hole 15 on the thick tube sheet 9 and the heat exchange tube 10, allowing cooling liquid to pass through the thick tube sheet 9 without clogging or gap corrosion. The plum blossom-shaped tube hole 15 on the thick tube sheet 9 is evenly distributed, ensuring uniform cooling liquid flow. Multiple liquid holes 16 are also uniformly distributed around the perimeter of the thick tube sheet 9. These holes do not pass through the heat exchange tubes 10, but rather provide smooth, unimpeded passages. Shell-side cooling water can flow through these holes and the gaps between the holes 15 and the heat exchange tubes 10.

[0052] In this embodiment, the width of the plate body 13 of the support plate 7 is smaller than the inner diameter of the shell-side cylinder 3, so that a gap is left between the plate body 13 and the shell-side cylinder 3, and a liquid flow channel is left between the shell-side cylinder 3 and the support plate 7, so that the outer ring of the shell side is also cooled by cooling water to avoid high-temperature failure.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A waste heat boiler with a flexible tube sheet structure comprises an inlet tube box, an outlet tube box, and a shell-side cylinder. The flexible tube sheet structure comprises a thin tube sheet and a thick tube sheet. The thin tube sheet is connected to the inlet tube box, and the thick tube sheet is connected to the shell-side cylinder. The shell-side cylinder has multiple heat exchange tubes built in. Both the thick tube sheet and the thin tube sheet have tube holes for the heat exchange tubes to pass through. The invention is characterized by: The flexible tube sheet structure further includes a plurality of bracing plates arranged in parallel, each of the bracing plates including a plate body and a plurality of tie rods arranged on the plate body. The thick tube sheet is provided with a plurality of arranged bosses, and the plate bodies of the plurality of bracing plates are butt-welded to the corresponding bosses of the thick tube sheet. The thin tube sheet is provided with multiple rows of support holes, and the multiple tie rods of the support plate are inserted into the corresponding rows of support holes and fixed by countersunk welding; one end of the heat exchange tube passes through the tube hole of the thick tube sheet, and then passes through between two adjacent support plates, and then connects to the inlet pipe box through the thin tube sheet; the shell-side cylinder is also provided with a rear tube sheet, and the other end of the heat exchange tube passes through the rear tube sheet and connects to the outlet pipe box; The plate body is provided with slots extending through its thickness; The width of the plate body of the bracing plate is smaller than the inner diameter of the shell-side cylinder, so that a gap is left between the plate body and the shell-side cylinder; The plate body and the pull rod of each of the tensioning plates are an integrated structure.

2. The waste heat boiler with a flexible tube sheet structure according to claim 1, characterized in that: The plate body is a square plate, and the end surface of the boss is a flat surface that matches the end surface of the plate body.

3. The waste heat boiler with a flexible tube sheet structure according to claim 1 or 2, characterized in that: The supporting hole is a circular hole, and the pull rod is a round rod that matches the supporting hole.

4. The waste heat boiler with a flexible tube sheet structure according to claim 1, characterized in that: There are a plurality of slots, and the slots are arranged along the width and length directions of the plate.

5. The waste heat boiler with a flexible tube sheet structure according to claim 1, characterized in that: The periphery of the tube hole is expanded with an extension groove, so that the tube hole is in a plum blossom shape; and / or the thick tube plate is provided with a plurality of liquid holes near its periphery.

6. The waste heat boiler with a flexible tube sheet structure according to claim 1, characterized in that: The end of the tie rod is flush with the end surface of the thin tube plate.

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