Shell and tube heat exchangers with composite tube sheets

Abstract

A shell-and-tube heat exchanger assembly is disclosed, comprising: a first tube sheet configured for attachment to a shell of the shell-and-tube heat exchanger assembly, the first tube sheet including: a first section and a second section; the second section configured for attachment to a first shell end of the shell; and the first section including a plurality of holes configured to support a plurality of corresponding aluminum tubes extending through the shell, wherein the first section is configured to limit the current response of the plurality of aluminum tubes when exposed to cooling water.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Application No. 62 / 873,571, filed July 12, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Exemplary embodiments relate to shell-and-tube heat exchangers, and more specifically to shell-and-tube heat exchangers having composite tube sheets. Background Technology

[0004] Shell-and-tube heat exchangers are a type of heat exchanger consisting of a shell and a bundle of tubes inside the shell. When aluminum tubes are used in a steel shell, these heat exchangers may experience tube wall thinning beyond permissible limits due to scaling and corrosion. This is due to the high galvanic corrosion pairing between dissimilar metals. For continuous operation of such heat exchangers, the tubes may need to be replaced periodically, leading to operational downtime. Summary of the Invention

[0005] A shell-and-tube heat exchanger assembly is disclosed, comprising: a first tube sheet configured for attachment to a shell of the shell-and-tube heat exchanger assembly, the first tube sheet including: a first section and a second section; the second section configured for attachment to a first shell end of the shell; and the first section including a plurality of holes configured to support a plurality of corresponding aluminum tubes extending through the shell, wherein the first section is configured to limit the current response of the plurality of aluminum tubes when exposed to cooling water.

[0006] In addition to one or more of the features disclosed above, or as an alternative, the first section includes a cladding metal.

[0007] In addition to one or more of the features disclosed above, or as an alternative, the first section includes an insert.

[0008] In addition to one or more of the features disclosed above, or as an alternative, the first section includes a polymer.

[0009] In addition to one or more of the features disclosed above, or as an alternative, the first segment has a rectangular surface area and is fixed to a cutout in the second segment, wherein the cutout is rectangular.

[0010] In addition to one or more of the features disclosed above, or as an alternative, the first segment is press-fitted into the second segment.

[0011] In addition to one or more of the features disclosed above, or as an alternative, the first section is welded to the second section.

[0012] In addition to one or more of the features disclosed above, or as an alternative, the first section is watertightly fixed to the second section.

[0013] In addition to one or more of the features disclosed above, or as an alternative, the component includes a first pressure chamber fixed to a first section, the first section having a surface area at least as large as the contact area between the first pressure chamber and the first section.

[0014] In addition to one or more of the features disclosed above, or as an alternative, the first tube sheet is formed of a polymer.

[0015] In addition to one or more of the features disclosed above, or as an alternative, the first tube sheet includes a hub-spoke-wheel assembly.

[0016] In addition to one or more of the features disclosed above, or as an alternative, the first segment includes a hub segment of a hub-spoke-wheel assembly, the second segment includes a wheel segment of a hub-spoke-wheel assembly, and the third segment of the assembly includes a spoke segment of a hub-spoke-wheel assembly, the third segment being radially located between the first segment and the second segment and connecting the first segment and the second segment to each other.

[0017] In addition to one or more of the features disclosed above, or as an alternative, the second section includes a first groove that extends axially and is configured to receive a first shell end of the shell.

[0018] In addition to one or more of the features disclosed above, or as an alternative, the second section includes a disk component integrated with the second section.

[0019] In addition to one or more of the features disclosed above, or as an alternative, the second section includes a plurality of spokes that are circumferentially spaced apart from each other and extend radially around the disc component.

[0020] In addition to one or more of the features disclosed above, or as an alternative, the first section includes a second groove that extends radially and is configured to be fixed to the disc component and the plurality of spokes.

[0021] In addition to one or more of the features disclosed above, or alternatively, a plurality of spokes are circumferentially forward of the disc component and have radially outer sides fixed to the radially lower side of the second section.

[0022] In addition to one or more of the features disclosed above, or as an alternative, the component includes a second tube sheet that is substantially the same as the first tube sheet.

[0023] In addition to one or more of the features disclosed above, or alternatively, the plurality of aluminum tubes are supported by a plurality of holes in a first section, wherein the first section comprises aluminum.

[0024] A method for guiding fluid through a shell-and-tube heat exchanger assembly is further disclosed, the method comprising: guiding a first fluid through a plurality of tubes extending through the shell; and guiding a second fluid through the shell outside the plurality of aluminum tubes without causing a corrosion reaction between the aluminum tubes and a first tube sheet of the shell-and-tube heat exchanger assembly. Attached Figure Description

[0025] The following description should not be construed as limiting in any way. Referring to the accompanying drawings, similar element numbers are similar:

[0026] Figure 1 A shell-and-tube heat exchanger assembly according to this disclosure is shown;

[0027] Figure 2 An exploded view of a shell-and-tube heat exchanger assembly according to one embodiment is shown;

[0028] Figure 3 An exploded view of a shell-and-tube heat exchanger assembly according to another embodiment is shown;

[0029] Figure 4 An exploded view of a shell-and-tube heat exchanger assembly according to another embodiment is shown;

[0030] Figure 5 It shows the use of Figure 4 Tube sheet of shell-and-tube heat exchanger assembly, wherein the tube sheet is polymer / plastic;

[0031] Figure 6 It shows Figure 4 Part of a shell-and-tube heat exchanger assembly, wherein the tube sheet is made of polymer / plastic; and

[0032] Figure 7 A method for guiding fluid through a shell-and-tube heat exchanger assembly is shown. Detailed Implementation

[0033] This document provides a detailed description of one or more embodiments of the disclosed apparatus and methods by way of example and not limitation, with reference to the accompanying drawings.

[0034] Go to Figures 1-2A shell-and-tube heat exchanger assembly (assembly) 100 is shown, comprising a shell 101 (i.e., a large container) and a plurality of aluminum tubes (aluminum tubes) 120 bundled within the shell 101. The shell 101 may have a plurality of ports 102 including a first port 102a and a second port 102b, the first port and the second port being an upstream port and a downstream port, respectively. In this disclosure, the terms upstream and downstream refer to the flow direction relative to the fluid within the aluminum tubes 120. The shell 101 may also have a discharge port 102c to discharge vapor formed within the shell 101 during a heat transfer cycle.

[0035] Although the embodiment without baffle 125 is within the scope of this disclosure, one or more baffles 125 may be present within the housing 101 (in Figure 1 (Illustrated schematically). Component 100 may include a plurality of pressure chambers (pressure chambers) 150 (sometimes referred to as tanks), including a first pressure chamber 150a and a second pressure chamber 150b, which may be an upstream pressure chamber and a downstream pressure chamber, respectively. Pressure chambers 150 are connected to housing 101 via a plurality of tube sheets (tube sheets) 160, including a first tube sheet 160a and a second tube sheet 160b, which may be an upstream tube sheet and a downstream tube sheet, respectively. Tube sheets 160 are fixed to a plurality of shell ends (shell ends) 165, including a first shell end 165a and a second shell end 165b, which may be an upstream shell end and a downstream shell end, respectively.

[0036] Component 100 is designed to allow multiple fluids 130, including a first fluid 130a and a second fluid 130b with different initial temperatures, to flow through it. The first fluid 130a flows through the aluminum tube 120 (tube side), while the second fluid 130b flows in the shell (shell side) but outside the aluminum tube 120. Heat is transferred between the fluids 130 through the aluminum tube 120, from the tube side to the shell side, or vice versa. On the shell or tube side, the fluid 130 can be liquid or gas. For efficient heat transfer, a generally large heat transfer area is required, necessitating numerous aluminum tubes 120, which are typically arranged horizontally inside the shell 101, which can be a cylindrical, tank-like structure.

[0037] Go to Figure 2 This shows additional features of component 100. Figure 2 include Figure 1 Each feature. For example Figure 2As shown, the aluminum tube 120 has opposing tube ends 140, including a first tube end 140a and a second tube end 140b, which can be an upstream tube end and a downstream tube end, respectively. The opposing tube ends 140 are connected to the pressure chamber 150 via a tube sheet 160. The tube sheet 160 may each include a plurality of holes (or openings) 180 as tube support holes, including a first set of tube support holes (first holes) 180a in the first tube sheet 160a and a second set of tube support holes (second holes) 180b in the second tube sheet 160b.

[0038] Shell 101 can be formed of steel. Figure 2 In this embodiment, the tube sheet 160 may be at least partially formed of steel for suitably welded to the shell 101. The aluminum tube 120 may be thin-walled. If the tube sheet 160 is formed entirely of untreated steel, the aluminum tube 120 and the tube sheet 160 will undergo chemical reactions over time, especially when the fluid 130 is conductive (e.g., water), leading to corrosion of the aluminum tube 120. The first tube end 140a, as the upstream end, may corrode at a higher rate than the second tube end 140b, as the downstream end. This may be due to a greater temperature difference between the first fluid 130a and the second fluid 130b at the upstream end compared to the downstream end.

[0039] According to the disclosed embodiments, one of the tube sheets 160 (e.g., the first tube sheet 160a) may be a composite tube sheet, which may include multiple segments (sections) 120, including a first section 210a and a second section 210b. The first section 210a may include a hole 180, and the second section 210b may be fixed to the housing 101. For example, the first section 210a may be a radially inner section, and the second section 210b may be a radially outer section.

[0040] In one embodiment, the first tube sheet 160a has a circular surface area, while the first segment 210a has a rectangular surface area. In one embodiment, the diameter D1 of the first tube sheet 160a is larger than each peripheral edge 215 of the first segment 210a. With this configuration, and with the first segment 210a located at the center of the first tube sheet 160a, the first segment 210a will avoid direct contact with the shell 101. As discussed below, the segment 210a may comprise a different material, such that this configuration avoids joining the shell 101 to a different material and potentially compromises the strength of the connection between the second segment 210b and the shell 101.

[0041] In one embodiment, the service life of component 100 is predetermined, and the current carrying capacity of the first section 210a is designed to protect the aluminum tube 120 during the service life of component 100. Therefore, downtime for replacing the aluminum tube 120 due to corrosion at the first tube sheet 160a can be avoided.

[0042] In one embodiment, the first segment 210a and the second segment 210b are formed from a continuous substrate such as steel. The first segment 210a may be clad. The cladding may be a rolled thin metal layer of aluminum or a suitable alloy, a sprayed coating, or other commercially produced cladding metal. The cladding material may be any material that is more electrochemically negative than the aluminum tube when exposed to cooling water. For example, materials with a lower electrochemical potential than the aluminum tube when exposed to cooling water (e.g., the cladding) may be aluminum alloys (e.g., including zinc and / or magnesium), pure zinc, pure magnesium, etc., which have higher electrochemical activity.

[0043] Go to Figure 3 Further embodiments are shown. Unless otherwise indicated, Figure 1 and Figure 2 The features of component 100 shown are included in this embodiment. Figure 3 In one embodiment, the second segment 210b includes a notch 220, and the first segment 210a is an insert fixed to the second segment 210b within the notch 220. In such an embodiment, the second segment 210b may be steel, while the first segment 210a may be the same material as the aluminum tube 120, or a material configured to limit the current response of the plurality of aluminum tubes 120 when exposed to cooling water. Although a chemical reaction may occur between the first segment 210a and the second segment 210b, the first segment 210a may be configured to survive the service life of the assembly 100. For example, the first segment 210a may be formed from a relatively thick aluminum plate. In one embodiment, the first segment 210a configured as an insert is a polymer. For example, the polymer may include monomers, copolymers, liquid crystal polymers (LCPs), polysulfones (PSUs), polyethersulfones (PESs), polyvinylidene fluoride (PVDFs), polyetherimides (PEIs), polyphenylene sulfide (PPSs), polyether ether ketones (PEEKs), styrene-butadiene copolymers (SBCs), polyketides (PKs), etc. The polymer may include reinforcing materials such as aromatic polyamide fibers, glass fibers, carbon fibers, carbon nanotubes, etc. The connection between the insert and the tube sheet may be mechanical (e.g., bolts and flanges), welded, inserted, glued, etc., for securing the insert to the tube sheet.

[0044] Cooling water as used herein may include pure water, drinking water, brine (e.g., brine, polyethylene, polypropylene, etc.), and treated water including additives (such as corrosion inhibitors or antifreeze).

[0045] In one embodiment, the surface dimension of the first segment 210a of the first tube sheet 160a is equal to or greater than the contact area between the first pressure chamber 150a and the first tube sheet 160a. This avoids a configuration where the first pressure chamber 150a is positioned on a non-watertight, uneven surface when, for example, the thickness of the first segment 210a differs from the thickness of the second segment 210b. The first segment 210a can be press-fitted into the second segment 210b, welded to the second segment 210b, or secured by another leak-proof process. In such an embodiment, the first tube sheet 160a can be a template for use with different coolers that require different configurations of the orifices 180 and / or different materials for the first segment 210a due to the use of different aluminum tubes 120 (e.g., with different thicknesses, outer diameters, flow areas, etc.). That is, the first segment 210a can be interchanged for different operating parameters.

[0046] exist Figure 3 In the embodiment shown, the second tube sheet 160b may be configured identically to the first tube sheet 160a. Therefore, for the sake of brevity, further discussion of the construction of the second tube sheet 160b is omitted.

[0047] Go to Figures 4-6 Another embodiment is shown. Unless otherwise indicated, Figure 1 and Figure 2 The features of component 100 shown are included in this embodiment. Figures 4-6 In one embodiment, the first tube sheet 160a is a disc-shaped polymer having a hub-spoke-wheel assembly.

[0048] In such an embodiment, the first section 210a is a hub section including the bore 180, and the first pressure chamber 150a is fixed to the first section 210a. Figure 6 The second segment 210b is a wheel segment, which is annular and connected to the housing 101 via an axially extending first groove 250. The third segment 210c of the assembly 100 is a spoke segment, which is annular and extends radially between the first segment 210a and the second segment 210b. The third segment 210c has a disc member 240a, which extends radially and is integrated with the second segment 210b. The third segment 210c has a plurality of spokes 240b, which are circumferentially spaced from each other and extend radially. The spokes 240b are axially ahead of the disc member 240a and serve to reinforce the third segment 210c. The radially outer side 242a of the spokes 240b contacts the radially lower side 242b of the second segment 210b to provide radial support. A second groove 260 extending radially in the first section 210a receives both the disc component 240a and the spoke 240b, wherein the front portion 270 of the second groove 260 forms a flange fixed relative to the spoke 240b. Figure 5The feature provided is an example of a structurally rational geometry for polymer / plastic tubing sheets. Other designs leading to structurally rational geometries for polymer / plastic tubing sheets are within the scope of this disclosure. It should be recognized that... Figure 6 The features described represent one embodiment of this disclosure and are not intended to limit the scope of this disclosure.

[0049] exist Figures 4-6 In the embodiment shown, the second tube sheet 160b may be configured identically to the first tube sheet 160a. Therefore, for the sake of brevity, further discussion of the construction of the second tube sheet 160b is omitted.

[0050] Figure 7 A method for guiding fluid through assembly 100 is disclosed. As shown in block 510, the method includes guiding a first fluid 130a through an aluminum tube 120 extending through housing 101. Block 520 illustrates guiding a second fluid 130b through housing 101 outside aluminum tube 120 without causing a corrosion reaction between aluminum tube 120 and first tube sheet 160a.

[0051] Using the above embodiments, current pairing between the aluminum tube 120 and the support structure of the assembly 100 can be selectively eliminated at one or two tube sheets 160.

[0052] The term “about” is intended to include the degree of error associated with a measurement of a specific quantity based on the equipment available at the time of filing. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The singular forms “a,” “an,” and “the” as used herein are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the terms “comprising” and / or “including” as used in this specification indicate the presence of the indicated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0053] While this disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes may be made and elements may be substituted with equivalents without departing from the scope of this disclosure. Furthermore, many modifications can be made to suit particular situations or materials to the teachings of this disclosure without departing from its essential scope. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed as the best mode for carrying out the concepts of this disclosure, but rather that this disclosure will include all embodiments falling within the scope of the claims.

Claims

1. A shell-and-tube heat exchanger assembly, comprising: A first tube sheet, configured as a shell for attachment to the shell-and-tube heat exchanger assembly, the first tube sheet comprising: First section and second section; The second section is configured to be fixed to the first shell end of the shell; and The first section includes a plurality of holes configured to support corresponding plurality of aluminum tubes extending through the housing, wherein the first section is configured to limit the current response of the plurality of aluminum tubes when exposed to cooling water. Wherein: the first segment is a radially inner segment, and the second segment is a radially outer segment; The first segment is an insert having a rectangular surface area, which is press-fitted or welded into a cutout in the second segment, which is disc-shaped; and A first pressure chamber, which is a water tank, is fixed to the first section, and the first section has a surface area at least as large as the contact area between the first pressure chamber and the first section.

2. The assembly of claim 1, wherein, The first segment includes a cladding metal.

3. The assembly of claim 1, wherein, The first segment includes a polymer.

4. The component according to claim 1, characterized in that, The first section is watertightly fixed to the second section.

5. The component according to claim 1, characterized in that, The first tube sheet is formed of polymer.

6. The component according to claim 5, characterized in that, The first tube sheet includes a hub-spoke-wheel assembly.

7. The component according to claim 6, characterized in that, The first section includes the hub section of the hub-spoke-wheel assembly, the second section includes the wheel section of the hub-spoke-wheel assembly, and the third section of the assembly includes the spoke section of the hub-spoke-wheel assembly, the third section being radially located between the first section and the second section and connecting the first section and the second section to each other.

8. The component according to claim 7, characterized in that, The second section includes a first groove that extends axially and is configured to receive a first shell end of the shell.

9. The component according to claim 8, characterized in that, The second section includes a disk component integrated with the second section.

10. The component according to claim 9, characterized in that, The second section includes a plurality of spokes that are circumferentially spaced apart from each other and extend radially around the disc component.

11. The component according to claim 10, characterized in that, The first section includes a second groove that extends radially and is configured to be fixed to the disc component and the plurality of spokes.

12. The component according to claim 10, characterized in that, The plurality of spokes are located axially in front of the disc component and have radially outer sides fixed to the radially lower side of the second section.

13. The component according to claim 1, characterized in that, The component includes a second tube sheet that is substantially the same as the first tube sheet.

14. The component according to claim 1, characterized in that, The plurality of aluminum tubes are supported by the plurality of holes in the first section, wherein the first section comprises aluminum.

15. A method for guiding fluid through a shell-and-tube heat exchanger assembly as claimed in any one of claims 1-14, the method comprising: The first fluid is guided through multiple tubes that extend through the shell; as well as A second fluid is guided through the shell outside the plurality of aluminum tubes without causing a corrosion reaction between the aluminum tubes and the first tube sheet of the shell-and-tube heat exchanger assembly.

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