Slotted baffle structure and heat exchanger for reducing tube sheet temperature difference

Abstract

The present invention relates to a slotted baffle structure and a heat exchanger for reducing tubesheet temperature differentials. The slotted baffle structure comprises a baffle body, the baffle body being provided with a plurality of first through-holes, each of which is for receiving a heat exchange tube; and a groove portion provided on one side of the baffle body, the groove portion allowing fluid to flow in. The slotted baffle structure for reducing tubesheet temperature differentials abuts against the shell-side side of the tubesheet, restricting the flow of the shell-side medium at the groove portion, and even forming a dead zone within the groove portion. This significantly increases the thermal resistance on the shell-side side, reduces the temperature differential across the tubesheet, reduces thermal stress in the tubesheet, and improves the structural strength of the heat exchanger tubesheet.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a slotted baffle structure for reducing the temperature difference between tube sheets and a heat exchanger. Background Art

[0002] Heat exchangers are widely used in petrochemical plants due to their robust structure, simple manufacturing, and high reliability. Among the various components of a heat exchanger, the tubesheet is both the most important and the most complex. Its function is to arrange the heat exchange tubes, separate the tube-side and shell-side fluids, and prevent mixing of the cold and hot fluids. It is also affected by the tube-side and shell-side pressures, as well as the thermal stress caused by the temperature difference between the tube and shell sides.

[0003] During normal operation, thermal stress significantly impacts the tubesheet, especially when the operating temperature difference between the tube and shell sides is large. This increases the thermal stress of the heat exchanger's tubesheet. When combined with the pressure stress and exceeding the allowable stress, plastic deformation may occur, affecting the tubesheet's normal operation. During startup and shutdown of the heat exchanger, the tubesheet temperature changes slowly, while the tubes change rapidly. This generates significant thermal stress at the tube-to-tubesheet connection. Rapid shutdown or sudden changes in intake air temperature can lead to cracking at the tubesheet-to-tube connection.

[0004] Therefore, how to effectively reduce the thermal stress intensity value is the key to improving the strength of the tube sheet and is of great significance to improving the safety of the heat exchanger.

[0005] Therefore, the inventors, relying on their many years of experience and practice in related industries, have proposed a slotted baffle structure and a heat exchanger for reducing the temperature difference between tube sheets, so as to overcome the defects of the prior art. Summary of the Invention

[0006] The object of the present invention is to provide a slotted baffle structure and a heat exchanger for reducing the temperature difference of the tube sheet. The slotted baffle structure for reducing the temperature difference of the tube sheet is closely attached to the side of the tube sheet close to the shell side. The flow of the medium on the shell side is restricted at the groove portion, and even a dead zone is formed in the groove portion, which greatly improves the thermal resistance on the shell side, reduces the temperature difference on both sides of the tube sheet, reduces the thermal stress of the tube sheet, and improves the structural strength of the tube sheet of the heat exchanger.

[0007] The object of the present invention is achieved in this way. A slotted partition structure for reducing the temperature difference of the tube sheet includes a partition body, and the partition body is provided with a plurality of first through holes, each of which is used to pass a heat exchange tube; a groove portion is provided on one side surface of the partition body, and the groove portion can allow fluid to flow in.

[0008] In a preferred embodiment of the present invention, the area of ​​the groove portion is greater than 60% of the side area of ​​the partition body.

[0009] In a preferred embodiment of the present invention, the groove portion includes a plurality of linear grooves arranged in parallel and at intervals, and both ends of each linear groove are open; and each first through hole is provided through each linear groove.

[0010] In a preferred embodiment of the present invention, the groove portion includes a spiral groove, and each of the first through holes is disposed through the spiral groove.

[0011] In a preferred embodiment of the present invention, the groove portion includes a plurality of coaxially arranged annular grooves, and each of the first through holes is provided through each of the annular grooves.

[0012] The object of the present invention can also be achieved in this way: a heat exchanger includes a heat exchanger shell and a plurality of heat exchange tubes, wherein a tube sheet can be sealably provided at a first end of the heat exchanger shell and a second end of the heat exchanger shell is sealably provided, and a side of the tube sheet away from the heat exchanger shell can be sealably connected to a hollow end head shell; each of the heat exchange tubes is sealably passed through the tube sheet, and both ends of each of the heat exchange tubes are communicated with an inner cavity of the end head shell, the inner cavity of the end head shell and the inner cavity of each of the heat exchange tubes constitute a tube side, and the inner cavity of the heat exchanger shell constitutes a shell side;

[0013] The aforementioned slotted partition structure for reducing the temperature difference of the tube sheet is arranged in the heat exchanger shell. One side of the groove portion of the partition body is abutted against the tube sheet. Each heat exchange tube is passed through the first through hole. A first flow gap is formed between the inner wall of the first through hole and the outer wall of the heat exchange tube. A second flow gap is formed between the outer peripheral side wall of the partition body and the inner wall of the heat exchanger shell.

[0014] In a preferred embodiment of the present invention, a distance tube is provided in the heat exchanger shell, and the distance tube is used to press against the partition body to make it rest against the tube sheet.

[0015] In a preferred embodiment of the present invention, the groove portion includes a plurality of parallel and spaced linear grooves, and both ends of each linear groove are open; each first through hole is arranged through each linear groove; the fluid in the shell side flows into each linear groove through the first flow gap and the second flow gap.

[0016] In a preferred embodiment of the present invention, the groove portion includes a spiral groove, and each of the first through holes is provided through the spiral groove; the fluid in the shell side flows into the spiral groove through the first flow gap and the second flow gap.

[0017] In a preferred embodiment of the present invention, the groove portion includes a plurality of coaxially arranged annular grooves, and each of the first through holes is provided through each of the annular grooves; the fluid in the shell side flows into each of the annular grooves through the second flow gap.

[0018] As described above, the slotted baffle structure and heat exchanger for reducing the temperature difference between tube sheets of the present invention have the following beneficial effects:

[0019] The slotted baffle structure for reducing tube sheet temperature differential of the present invention is a structural component that can change the flow path of a portion of the shell-side medium without bearing pressure, does not require strength verification, and can meet structural requirements with a relatively thin thickness. It is durable, inexpensive, easy to purchase, manufacture, and maintain, has strong replaceability, and has good economic performance. The slotted baffle structure for reducing tube sheet temperature differential of the present invention can be applied to heat exchangers for reducing tube sheet temperature differential, and can also be applied to various other fields where temperature differential deformation occurs. It is particularly suitable for working conditions where the shell-side temperature differential is greater than 100°C, the shell-side medium is saturated water, and other fields with stringent requirements on tube sheet conditions.

[0020] In the heat exchanger of the present invention, the slotted baffle structure for reducing the temperature difference of the tube sheet is pressed against the side of the tube sheet close to the shell side. A groove portion is provided on the slotted baffle structure for reducing the temperature difference of the tube sheet, and the groove portion is pressed against the tube sheet. The medium on the shell side is restricted from flowing at the groove portion, and even a dead zone is formed in the groove portion, which greatly improves the thermal resistance on the shell side, makes the temperature of the tube sheet closer to the tube side, greatly reduces the temperature gradient, narrows the temperature difference on both sides of the tube sheet, reduces the thermal stress of the tube sheet, and improves the structural strength of the heat exchanger tube sheet. While ensuring safety and reliability, the design structure is compact and has good economic performance. The slotted baffle for reducing the temperature difference of the tube sheet of the present invention occupies a small space, has a negligible effect on the heat transfer area of ​​the heat exchange tube, and has no effect on other components. It ensures that the heat transfer calculation and structural design of the heat exchanger are the same as those of an ordinary heat exchanger, and is easy to promote the structure in new and modified equipment, and has a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0022] in:

[0023] Figure 1 : is a schematic diagram of a heat exchanger of the present invention.

[0024] Figure 2 : A cross-sectional view of a slotted baffle structure for reducing the temperature difference between tube sheets according to the present invention.

[0025] Figure 3 : It is a schematic diagram when the groove portion of the present invention is a straight groove.

[0026] Figure 4 : is a schematic diagram of the case where the groove portion of the present invention is a spiral groove.

[0027] Figure 5 : is a schematic diagram of the groove portion of the present invention when it is an annular groove.

[0028] In the picture:

[0029] 100. Heat exchanger;

[0030] 1. Slotted baffle structure for reducing tube sheet temperature difference;

[0031] 11. Partition body;

[0032] 12. a first through hole;

[0033] 131. Linear groove; 132. Spiral groove; 133. Annular groove;

[0034] 2. Heat exchanger shell;

[0035] 3. Heat exchange tube;

[0036] 4. Tube sheet;

[0037] 5. Terminal housing;

[0038] 6. Fixed distance tube. DETAILED DESCRIPTION

[0039] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0040] The specific embodiments of the present invention described herein are intended only to illustrate the present invention and are not to be construed as limiting the present invention in any way. In light of the present invention, a skilled person may conceive of any possible variations based on the present invention, all of which should be considered to fall within the scope of the present invention. It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to mechanical or electrical connections, or to internal communication between two elements, and may be directly connected or indirectly connected through an intermediate medium. A person of ordinary skill in the art can understand the specific meanings of the above terms based on the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] like Figures 2 to 5 As shown, the present invention provides a slotted baffle structure 1 for reducing tube-sheet temperature differences. The structure comprises a baffle body 11 having a plurality of first through-holes 12 formed therein, each of which is adapted to receive a heat exchange tube. A groove is formed on one side of the baffle body 11 to allow fluid flow. The baffle body 11 is relatively thin and can be made of steel plate.

[0043] The slotted baffle structure for reducing the temperature difference of the tube sheet of the present invention is a structural component, which can change the flow path of a portion of the shell-side medium without bearing pressure, does not require strength verification, and can meet structural requirements with a relatively thin thickness. It is durable, low-cost, easy to purchase, manufacture and maintain, has strong replaceability, and has good economic performance.

[0044] The slotted baffle structure for reducing the temperature difference of the tube sheet of the present invention can be applied to heat exchangers for reducing the temperature difference of the tube sheet, and can also be applied to various other fields where temperature difference deformation exists. It is particularly suitable for working conditions where the temperature difference between the shell and tube side is greater than 100°C, the shell side medium is saturated water, and other fields with stringent requirements on tube sheet conditions.

[0045] Furthermore, the area of ​​the groove portion is greater than 60% of the side area of ​​the partition body 11 to reduce metal heat conduction.

[0046] The groove portion on the partition body 11 can be designed in a variety of slotting methods as needed, and the specific methods are as follows:

[0047] like Figure 3 As shown, the groove portion can be a plurality of linear grooves 131 arranged in parallel and at intervals, and both ends of each linear groove 131 are open; each first through hole 12 is arranged to penetrate each linear groove 131.

[0048] like Figure 4 As shown, the groove portion may be a spiral groove 132 , and each first through hole 12 is disposed through the spiral groove 132 .

[0049] like Figure 5 As shown, the groove portion can be a plurality of coaxially arranged annular grooves 133 , and each first through hole 12 is arranged through each annular groove 133 .

[0050] like Figure 1As shown, the present invention also provides a heat exchanger 100 comprising a heat exchanger shell 2 and a plurality of heat exchange tubes 3. A tube sheet 4 can be sealably mounted on the first end of the heat exchanger shell 2, and a seal can be mounted on the second end of the heat exchanger shell 2. The side of the tube sheet 4 facing away from the heat exchanger shell can be sealably connected to a hollow end shell 5. Each heat exchange tube 3 is sealably mounted through the tube sheet 4, and both ends of each heat exchange tube 3 are connected to the inner cavity of the end shell. The inner cavity of the end shell 5 and the inner cavity of each heat exchange tube 3 constitute the tube side, while the inner cavity of the heat exchanger shell 2 constitutes the shell side. In this embodiment, the end shell 5, tube sheet 4, and heat exchanger shell 2 are connected by flanges. Fluid inlets and fluid outlets are provided on the sidewalls of the end shell 5 and the heat exchanger shell 2.

[0051] The heat exchanger shell 2 is equipped with the aforementioned slotted baffle structure 1 for reducing the temperature difference between the tube sheets. One side of the baffle body 11, with its grooved portion, rests against the tube sheet 4. The baffle body 11's straightness is required to be consistent with that of the tube sheet 4, ensuring a tight fit. Each heat exchange tube 3 passes through a first through-hole 12. A first flow gap is formed between the inner wall of the first through-hole 12 and the outer wall of the heat exchange tube 3, while a second flow gap is formed between the outer peripheral sidewall of the baffle body 11 and the inner wall of the heat exchanger shell 2. The tolerance of the first through-hole 12 on the baffle body 11 is consistent with that of the baffle (existing technology), preventing crevice corrosion and fatigue damage caused by the expansion of the heat exchange tube 3 being constrained by the first through-hole 12. The baffle body 11 is chamfered on the outer circumference for ease of installation.

[0052] The diameter of the baffle body 11 can be referenced to the dimensions of a baffle (existing technology) and is slightly smaller than the inner diameter of the heat exchanger shell 2. The distribution of the first through-holes 12 in the baffle body 11 is consistent with the layout of the heat exchange tubes 3. The heat exchange tubes pass through the baffle body 11 and the tube sheet 4 and are connected to the tube sheet 4.

[0053] For heat exchanger structures with large temperature differentials between the shell and tube sides, temperature loads can cause significant thermal stresses in the tubesheet. There are two key factors influencing thermal stress: the heat exchanger's structural form, namely, tubesheet thickness and structural discontinuities. According to shell-and-tube heat exchanger design standards, reducing the tubesheet thickness can help reduce thermal stress, but this also reduces pressure-bearing capacity. Especially for heat exchangers subject to both high and low temperature differentials, thinning the tubesheet is not feasible. Thermal stress along the thickness of the tubesheet is extremely high, and temperature loads are likely to be the primary factor causing the heat exchanger to fail strength verification. Another factor is the heat exchanger's process design, namely, fluid temperature and flow path. However, changes to the process design can alter the heat exchanger's heat transfer area and heat transfer coefficient, representing a major modification or redesign of the entire heat exchanger, potentially preventing it from meeting operating conditions and achieving its intended performance. Therefore, finding ways to effectively reduce thermal stress intensity through minor structural changes is crucial and is the key to improving the strength of a heat exchanger's tubesheet.

[0054] The present invention shares its structural similarity with conventional heat exchangers in that the tubesheet separates the tubeside from the shellside, with the heat exchange tubes serving as heat transfer elements. In the heat exchanger of the present invention, a slotted baffle structure for reducing the tubesheet temperature difference rests against the shell-side side of the tubesheet. A grooved portion is provided on the baffle structure, which is in close contact with the tubesheet. The flow of the medium on the shell side is restricted at the grooved portion, even forming a dead zone within the grooved portion. This significantly increases the thermal resistance on the shell side, bringing the tubesheet temperature closer to the tubeside, significantly reducing the temperature gradient, narrowing the temperature difference across the tubesheet, reducing thermal stress on the tubesheet, and improving the structural strength of the heat exchanger tubesheet. While ensuring safety and reliability, the design is compact and economical. The slotted baffle structure for reducing the tubesheet temperature difference of the present invention occupies little space, has minimal impact on the heat transfer area of ​​the heat exchange tubes, and has no impact on other components. This ensures that the heat transfer calculation and structural design of the heat exchanger are the same as those of conventional heat exchangers, making it easy to promote the structure in new and modified equipment and having wide applicability.

[0055] Further, if Figure 1 As shown, spacer tubes 6 are installed within the heat exchanger shell 2. These spacer tubes 6 abut the bulkhead body 11, securing it against the tube sheet 4. The slotted bulkhead structure 1, designed to reduce tubesheet temperature differences, adheres tightly to the shell-side of the tube sheet solely through the spacer tubes 6, eliminating the need for additional fixing components. This design ensures the heat transfer calculations and structural design of the heat exchanger are identical to those of conventional heat exchangers, facilitating its widespread adoption in both new and retrofitted equipment.

[0056] Further, if Figure 3 As shown, the groove portion is a plurality of linear grooves 131 arranged in parallel and spaced apart, and both ends of each linear groove 131 are open; each first through hole 12 is set through each linear groove 131; the fluid in the shell side flows into each linear groove 131 through the first flow gap and the second flow gap.

[0057] Further, if Figure 4 As shown, the groove portion is a spiral groove 132 , and each first through hole 12 is provided through the spiral groove 132 ; the fluid in the shell side flows into the spiral groove 132 through the first flow gap and the second flow gap.

[0058] Further, if Figure 5 As shown, the groove portion includes a plurality of coaxially arranged annular grooves 133 , and each first through hole 12 is provided through each annular groove 133 ; the fluid in the shell side flows into each annular groove 133 through the second flow gap.

[0059] Both the first and second flow gaps are very small. Consequently, the flow of the shell-side medium in the groove is restricted, even forming a dead zone within the groove. Because the heat transfer coefficient of the gas-liquid medium outside the groove is much lower than that of steel, the presence of the slotted baffle structure 1, which is used to reduce the temperature difference between the tubesheet and the shell, significantly increases the thermal resistance between the shell and the tubesheet, bringing the tubesheet temperature closer to that of the tubeside. This significantly reduces the temperature gradient, narrows the temperature difference across the tubesheet, and reduces thermal stress on the tubesheet.

[0060] As described above, the slotted baffle structure and heat exchanger for reducing the temperature difference between tube sheets of the present invention have the following beneficial effects:

[0061] The slotted baffle structure for reducing tube sheet temperature differential of the present invention is a structural component that can change the flow path of a portion of the shell-side medium without bearing pressure, does not require strength verification, and can meet structural requirements with a relatively thin thickness. It is durable, inexpensive, easy to purchase, manufacture, and maintain, has strong replaceability, and has good economic performance. The slotted baffle structure for reducing tube sheet temperature differential of the present invention can be applied to heat exchangers for reducing tube sheet temperature differential, and can also be applied to various other fields where temperature differential deformation occurs. It is particularly suitable for working conditions where the shell-side temperature differential is greater than 100°C, the shell-side medium is saturated water, and other fields with stringent requirements on tube sheet conditions.

[0062] In the heat exchanger of the present invention, the slotted baffle structure for reducing the temperature difference of the tube sheet is pressed against the side of the tube sheet close to the shell side. A groove portion is provided on the slotted baffle structure for reducing the temperature difference of the tube sheet, and the groove portion is pressed against the tube sheet. The medium on the shell side is restricted from flowing at the groove portion, and even a dead zone is formed in the groove portion, which greatly improves the thermal resistance on the shell side, makes the temperature of the tube sheet closer to the tube side, greatly reduces the temperature gradient, narrows the temperature difference on both sides of the tube sheet, reduces the thermal stress of the tube sheet, and improves the structural strength of the heat exchanger tube sheet. While ensuring safety and reliability, the design structure is compact and has good economic performance. The slotted baffle for reducing the temperature difference of the tube sheet of the present invention occupies a small space, has a negligible effect on the heat transfer area of ​​the heat exchange tube, and has no effect on other components. It ensures that the heat transfer calculation and structural design of the heat exchanger are the same as those of an ordinary heat exchanger, and is easy to promote the structure in new and modified equipment, and has a wide range of applicability.

[0063] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A heat exchanger comprising a heat exchanger shell and a plurality of heat exchange tubes, characterized in that: The first end of the heat exchanger shell can be sealably provided with a tube sheet, and the second end of the heat exchanger shell is also sealably provided. The side of the tube sheet away from the heat exchanger shell can be sealably connected to a hollow end head shell. Each of the heat exchange tubes is sealably passed through the tube sheet, and both ends of each of the heat exchange tubes are communicated with the inner cavity of the end head shell. The inner cavity of the end head shell and the inner cavity of each of the heat exchange tubes constitute a tube side, and the inner cavity of the heat exchanger shell constitutes a shell side. A slotted baffle structure for reducing the temperature difference of the tube sheet is provided in the heat exchanger shell. The slotted baffle structure for reducing the temperature difference of the tube sheet includes a baffle body, a plurality of first through holes are provided on the baffle body, and a groove portion is provided on one side surface of the baffle body, and the groove portion can allow fluid to flow in; one side of the baffle body where the groove portion is provided is against the tube sheet, and each heat exchange tube is passed through the first through hole, and a first flow gap is formed between the inner wall of the first through hole and the outer wall of the heat exchange tube, and a second flow gap is formed between the outer peripheral side wall of the baffle body and the inner wall of the heat exchanger shell; the area of ​​the groove portion is greater than 60% of the side area of ​​the baffle body.

2. The heat exchanger according to claim 1, wherein A distance tube is provided in the heat exchanger shell, and the distance tube is used to press against the partition body so that it rests against the tube sheet.

3. The heat exchanger according to claim 1, wherein The groove portion includes a plurality of linear grooves arranged in parallel and at intervals, and both ends of each linear groove are open; each first through hole is arranged through each linear groove; the fluid in the shell side flows into each linear groove through the first flow gap and the second flow gap.

4. The heat exchanger according to claim 1, wherein The groove portion includes a spiral groove, and each of the first through holes is provided through the spiral groove; the fluid in the shell side flows into the spiral groove through the first flow gap and the second flow gap.

5. The heat exchanger according to claim 1, wherein The groove portion includes a plurality of coaxially arranged annular grooves, and each of the first through holes is provided through each of the annular grooves; the fluid in the shell side flows into each of the annular grooves through the second flow gap.

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