Lining pipe structure for heat exchange device and heat exchange device

Abstract

The invention provides a lining pipe structure for a heat exchange device and the heat exchange device. The lining pipe structure comprises one or more lining pipes, and the mounting structure is connected with the lining pipe, and the mounting structure is used for being connected or welded and fixed with the main steam pipe plate, so that the lining pipe is reliably fixed in the heat exchange pipe at the main steam pipe plate and / or the hole of the main steam pipe plate. Wherein the lining pipe is arranged in a heat exchange pipe at the main steam pipe plate and / or an open pore of the main steam pipe plate in a penetrating manner, a gap is formed between the lining pipe and the heat exchange pipe and / or the open pore, and fluid in the gap is in a stagnation state or the fluid speed is smaller than 2m / s, so that the thermal resistance between steam and the heat exchange pipe and / or the main steam pipe plate is increased. And / or, a heat insulation coating or structure is arranged on the surface of the lining pipe, so that the heat resistance between the steam and the heat exchange pipe and / or the main steam pipe plate is increased. Thus, the endurance capacity of structures such as the main steam pipe plate to the main steam temperature difference is enhanced, the operation margin of the steam generator is improved, the service life of the steam generator is prolonged, and the yield and quality of steam are improved.

Description

Technical Field

[0001] This application relates to the field of steam generating equipment technology, and in particular to an inner liner tube structure and a heat exchange device for a heat exchanger. Background Technology

[0002] Direct-flow steam generators can directly produce superheated steam as well as steam with ultra-high pressure and supercritical parameters, resulting in higher power generation efficiency. They are also compact in structure and widely used in nuclear power generation and other power applications. However, in actual use, when there is a large temperature difference between adjacent areas of the main steam tube sheet, a significant temperature gradient will form at the boundary between these areas, leading to substantial thermal stress and affecting the reliable operation and service life of the steam generator. Summary of the Invention

[0003] This application provides an inner liner tube structure and a heat exchange device for a heat exchanger, in order to solve at least some of the problems in the related art.

[0004] In a first aspect, embodiments of this application provide an inner liner structure for a heat exchanger, the heat exchanger including a main steam tube sheet, at least a portion of the main steam tube sheet having openings, and at least a portion of the main steam tube sheet containing heat exchange tubes; the inner liner structure includes:

[0005] One or more inner liner tubes;

[0006] The mounting structure is connected to the inner liner tube and is used to connect or weld to the main steam tube sheet to reliably fix the inner liner tube in the heat exchange tube and / or the opening of the main steam tube sheet.

[0007] The inner liner is used to pass through the heat exchange tubes and / or openings in the main steam tube sheet, forming a gap between the inner liner and the heat exchange tubes and / or the openings. Within this gap, the fluid is stagnant or its velocity is less than 2 m / s, thereby increasing the thermal resistance between the steam and the heat exchange tubes or the main steam tube sheet; and / or

[0008] The surface of the inner liner tube is provided with a heat-insulating coating or structure to increase the thermal resistance between the steam and the heat exchange tube and / or the main steam tube sheet.

[0009] In some possible implementations, the length of the liner tube inserted into the heat exchange tube and / or the opening in the main steam tube sheet covers the entire thickness of the main steam tube sheet.

[0010] In some possible implementations, the liner tube is positioned inside the heat exchange tube and / or in the main steam tube sheet opening such that the liner tube is at the center of the heat exchange tube or the opening, to ensure that the gap between the liner tube and the heat exchange tube and / or the opening is uniformly distributed circumferentially.

[0011] In some possible implementations, the stiffness of the liner is configured to prevent flow-induced vibrations when the liner is subjected to the scouring of the internal fluid medium.

[0012] In some possible implementations, the side of the liner tube that is inserted into the opening of the main steam tube sheet or the heat exchange tube is provided with a flared structure. The outer diameter of the flared structure is slightly larger than the size of the opening of the main steam tube sheet or the heat exchange tube, so as to achieve elastic fixation between the liner tube and the wall of the heat exchange tube or the inner wall of the opening of the main steam tube sheet, thereby improving the installation rigidity of the liner tube.

[0013] In some possible implementations, the flared structure is provided with a slot that extends axially along the inner liner tube to make the end structure elastic and improve the long-term effectiveness of the flared structure's clamping force.

[0014] In some possible implementations, the mounting structure is a detachable fixing structure; all inner liner tubes are fixed together as a whole; or the inner liner tubes are divided into several areas and each area is fixed as a whole; or each inner liner tube is fixed individually; or

[0015] The installation structure is a permanent, fixed structure.

[0016] In some possible implementations, the mounting structure is fixed to the side of the liner pipe near the main steam tube sheet. The mounting structure is pre-set with a reasonable flow limiting or flow blocking structure to reduce the flow velocity of the fluid in the gap and prevent or reduce the axial flow of the fluid along the gap.

[0017] In some possible implementations, the mounting structure includes:

[0018] The support fixing plate includes a first surface and a second surface opposite to each other. The first surface has a plurality of first stepped countersunk holes that extend to the second surface. The inner lining tube passes through the first stepped countersunk holes. The support fixing plate is used to connect with the main steam tube sheet.

[0019] A pressure cover plate is fixedly connected to the first surface, and the pressure cover plate is used to press the inner liner tube into the first stepped countersunk hole.

[0020] In some possible implementations, a first stepped groove is formed on the inner wall of the first stepped countersunk hole, and the first stepped groove is located on one side of the first surface.

[0021] The outer periphery of the inner liner tube has a first stepped structure formed radially, the first stepped structure is engaged in the first stepped groove, and the pressing cover plate is used to press the first stepped structure into the first stepped groove.

[0022] In some possible implementations, the mounting structure further includes a first elastic member sleeved on the inner liner and located within the first stepped groove, with one end of the first elastic member abutting against the first stepped structure and the other end abutting against the clamping cover plate.

[0023] In some possible implementations, the outer edge of the support fixing plate is provided with a support ring, and the support fixing plate is also provided with a first fixing hole, the axis of the first fixing hole being parallel to the axis of the first stepped countersunk hole.

[0024] The mounting structure also includes fasteners for fixing the main steam tube sheet through the first fixing hole.

[0025] In some possible implementations, the support fixing plate is provided with a plurality of second fixing holes, the axial direction of the second fixing holes being parallel to the axial direction of the first stepped countersunk hole;

[0026] The mounting structure also includes fasteners that pass through the clamping cover and are fixedly connected to the second fixing hole.

[0027] In some possible implementations, the support fixing plate is formed by splicing together multiple sub-fixing plates; and / or

[0028] The clamping cover is composed of multiple sub-covers joined together.

[0029] In some possible implementations, the outer periphery of the inner liner tube extending from the second surface is radially formed with an installation positioning structure, which is used to limit the opening of the heat exchange tube or the main steam tube sheet.

[0030] In some possible implementations, the mounting and positioning structure is a stepped surface structure or a conical surface structure.

[0031] In some possible implementations, the mounting structure includes a plurality of inner liner fastening structures fitted around the outer periphery of the inner liner, the inner liner fastening structures being used to connect to the heat exchange tubes or the main steam tube sheet.

[0032] In some possible implementations, the inner liner fastening structure has a second stepped countersunk hole, and the inner wall of the second stepped countersunk hole has a second stepped groove.

[0033] The outer periphery of the inner liner tube has a second step structure formed radially, and the second step structure is engaged in the second stepped groove.

[0034] In some possible implementations, the mounting structure further includes a second elastic member sleeved on the inner liner and located within the second stepped groove, with one end of the second elastic member abutting against the second stepped structure and the other end abutting against the groove wall of the second stepped groove.

[0035] In some possible implementations, the plurality of inner liner tube fastening structures are interconnected as a single structure.

[0036] In a second aspect, embodiments of this application provide a heat exchange device, including: a main steam tube sheet, a plurality of heat exchange tubes and an inner lining tube structure as described in the first aspect, wherein the mounting structure is fixedly connected to the main steam tube sheet, and the main steam tube sheet has a plurality of openings, wherein at least a portion of the openings are through which the heat exchange tubes pass.

[0037] Wherein, at least a portion of the opening is perforated by the inner liner tube, and a gap is formed between the inner liner tube and the opening, wherein the fluid in the gap is stagnant or the fluid velocity is less than 2 m / s, so as to increase the thermal resistance between the steam and the main steam tube sheet; and / or

[0038] At least a portion of the heat exchange tubes are perforated by the inner liner tube, and a gap is formed between the inner liner tube and the heat exchange tubes. The fluid within the gap is stagnant or has a velocity less than 2 m / s, thereby increasing the thermal resistance between the steam and the heat exchange tubes; and / or

[0039] The surface of the inner liner tube is provided with a heat-insulating coating or structure to increase the thermal resistance between the steam and the heat exchange tube and / or the main steam tube sheet.

[0040] Thirdly, embodiments of this application provide a heat exchange device, including: a main steam tube sheet and an inner lining tube structure as described in the first aspect, wherein the mounting structure is fixedly connected to the main steam tube sheet, and the main steam tube sheet has a plurality of openings;

[0041] Wherein, at least a portion of the opening is perforated by the inner liner tube, and a gap is formed between the inner liner tube and the opening, wherein the fluid in the gap is stagnant or the fluid velocity is less than 2 m / s, so as to increase the thermal resistance between the steam and the main steam tube sheet; and / or

[0042] The surface of the inner liner tube is provided with a heat-insulating coating or structure to increase the thermal resistance between the steam and the heat exchange tube and / or the main steam tube sheet.

[0043] The liner tube structure provided in this application uses an installation structure to fix the liner tube. A gap is formed between the liner tube and the opening of the heat exchange tube or main steam tube sheet. The fluid in the gap is in a stagnant state or the fluid velocity is less than 2m / s. Alternatively, a heat insulation coating or structure can be provided on the surface of the liner tube. This can increase the thermal resistance between the main steam and the main steam tube sheet and / or heat exchange tube, enhance the tolerance of the main steam tube sheet and other structures to the temperature difference of the main steam, reduce the peak thermal stress caused by the temperature difference of the main steam tube sheet and other structures, improve the operating margin and service life of the steam generator, and ensure the increase in steam output and quality.

[0044] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0045] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0046] Figure 1 This is a cross-sectional view of a steam generator according to this application.

[0047] Figure 2 for Figure 1 The image shows a partial enlarged view of point A in one embodiment.

[0048] Figure 3 and Figure 4 for Figure 1 The diagram shows a partial enlarged view of point A in another embodiment.

[0049] Figure 5 and Figure 6 for Figure 1 The image shown is a partial enlarged view of point A in another embodiment.

[0050] Figure 7 for Figure 1 The enlarged view of section B shown.

[0051] Figure 8 for Figure 1 The enlarged view of point C shown.

[0052] Figure 9 for Figure 1 The enlarged view of point D shown.

[0053] Figure 10 for Figure 1 The view shown is in the direction E.

[0054] Figure 11 for Figure 1A schematic diagram of a splicing structure of the support and fixing plate of the inner lining tube structure of the steam generator shown.

[0055] Wherein: 100, inner lining tube structure; 110, support fixing plate; 111, first stepped countersunk hole; 112, support ring; 113, first fixing hole; 114, second fixing hole; 115, first stepped groove; 116, sub-fixing plate; 120, inner lining tube; 121, first step structure; 122, flared structure; 123, slot; 124, positioning boss; 125, second step structure; 126, installation positioning structure; 130, first elastic element; 140, clamping cover plate; 150, fastener; 160, inner lining tube fastening structure; 161, second stepped countersunk hole; 162, second stepped groove; 163, second elastic element; 200, main steam tube sheet; 300, heat exchange tube. Detailed Implementation

[0056] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0057] During actual use of a steam generator, deviations between the flow rate of the heat transfer medium and the heat exchange capacity will cause variations in the steam temperature. Specifically, the steam temperature in some areas will be higher than the average steam temperature, while in others it will be lower. These temperature deviations will also cause changes in the temperature of the main steam tube sheet. When the temperature deviation between adjacent areas of the main steam tube sheet is significant, a large temperature gradient will form at the boundary between these areas, resulting in substantial thermal stress and affecting the reliable operation and service life of the steam generator.

[0058] Therefore, this application provides an inner liner tube structure and a heat exchange device, which can be a steam generator or other equipment with heat exchange function. Taking a steam generator as an example, this inner liner tube structure is applied in the fields of nuclear power generation and power, which can enhance the tolerance of the main steam tube sheet and other structures of the steam generator to the temperature difference of the main steam, improve the operating margin and service life of the steam generator, and ensure the increase of steam output and quality. Of course, in other embodiments of this application, this inner liner tube structure can also be applied to other fields that require enhanced tolerance to temperature differences or peak temperatures of the heat exchange medium.

[0059] To better understand the technical solution of this application, the inner liner tube structure and heat exchange device of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementations can be combined with each other.

[0060] See Figures 1 to 3 As shown, embodiments of this application provide a heat exchange device, which can be a steam generator or heat exchanger, or other equipment with heat exchange functions. The following embodiments all use a steam generator as an example. In one embodiment, the steam generator includes a main steam tube sheet 200 and an inner liner structure 100, with the main steam tube sheet 200 having multiple openings. In another embodiment, the steam generator includes a main steam tube sheet 200, multiple heat exchange tubes 300, and an inner liner structure 100, with the main steam tube sheet 200 having multiple openings, and at least some of the openings housing heat exchange tubes 300.

[0061] The inner liner structure 100 includes:

[0062] One or more inner liner tubes 120 are used to pass through the openings of the heat exchange tubes 300 and / or the main steam tube sheet 200, forming a gap between the inner liner tubes 120 and / or the openings of the heat exchange tubes 300 and / or the main steam tube sheet 200. The fluid within the gap is in a stagnant state or the fluid velocity is less than 2 m / s, i.e., in a laminar flow state, to increase the thermal resistance between the steam and the heat exchange tubes 300 or the main steam tube sheet. Alternatively, the surface of the inner liner tube 120 may be provided with a heat-insulating coating or structure to increase the thermal resistance between the steam and the heat exchange tubes 300 and / or the main steam tube sheet 200. Optionally, the inner liner tube 120 may undergo surface treatment or have additional structures added, such as spraying a thermal barrier (insulating) coating or structure onto the surface of the inner liner tube 120. The heat exchange tubes and the main steam tube sheet are connected by expansion joints and / or welding. The heat exchange tubes and the main steam tube sheet are connected by butt welding via internal hole welding.

[0063] An installation structure is connected to the inner liner 120. This installation structure is used to connect to or weld the inner liner 120 to the main steam tube sheet 200 to fix its position within the openings of the heat exchange tubes and / or the main steam tube sheet 200. Depending on the specific requirements of the actual project, this fixing method can be either detachable or permanent.

[0064] Understandably, in embodiments where the steam generator includes heat exchange tubes 300, at least a portion of the main steam tube sheet 200 has an inner liner tube 120 inserted through its openings, forming a gap between the inner liner tube 120 and the openings of the main steam tube sheet 200. This gap is either a fluid stagnation zone or the fluid within the gap is in a laminar flow state, thereby increasing the thermal resistance between the steam and the main steam tube sheet 200. Alternatively, at least a portion of the heat exchange tubes 300 has an inner liner tube 120 inserted through its openings, forming a gap between the inner liner tube 120 and the heat exchange tubes 300. This gap is either a fluid stagnation zone or the fluid within the gap is in a laminar flow state, thereby increasing the thermal resistance between the steam and the heat exchange tubes 300. Alternatively, an inner liner 120 may be installed in at least part of the opening of the main steam tube sheet 200 and in at least part of the heat exchange tube 300, with gaps formed between the inner liner 120 and the heat exchange tube 300 and the opening of the main steam tube sheet 200. The gaps are fluid stagnation zones or the fluid in the gaps is in a laminar flow state, so as to increase the thermal resistance between the steam and the heat exchange tube 300 and the main steam tube sheet 200.

[0065] In embodiments where the steam generator does not include the heat exchange tube 300, at least a portion of the openings in the main steam tube sheet 200 are fitted with an inner liner tube 120, and a gap is formed between the inner liner tube 120 and the openings in the main steam tube sheet 200. The gap is a fluid stagnation zone or the fluid in the gap is in a laminar flow state, so as to increase the thermal resistance between the steam and the main steam tube sheet 200.

[0066] With the above-described configuration, the inner liner structure 100 provided in this application uses an installation structure to fix the position of the inner liner 120. A gap is formed between the inner liner 120 and the openings of the heat exchange tube 300 and / or the main steam tube sheet 200. This gap is a fluid stagnation zone, or the fluid within the gap is in a laminar flow state, so that the steam flow rate is stagnant or at a low velocity. Alternatively, a heat-insulating coating or structure can be provided on the surface of the inner liner 120. This reduces the temperature gradient of the main steam tube sheet 200 in areas with a large main steam temperature gradient, thereby reducing the thermal stress caused by the temperature difference gradient. This increases the thermal resistance between the main steam and the main heat exchange tube 300 and / or the main steam tube sheet 200, enhances the tolerance of the main steam tube sheet 200 and other structures to the main steam temperature difference, reduces the peak thermal stress of the main steam tube sheet 200 and other structures caused by the main steam temperature difference, improves the operating margin and service life of the steam generator, and ensures improved steam output and quality. It should be noted that the inner liner structure 100 can be used not only in steam generators, but also in other equipment that requires enhanced tolerance to temperature differences or peak temperatures of the heat exchange medium.

[0067] See Figure 3As shown, in some possible embodiments, a plurality of positioning bosses 124 are formed radially on the outer periphery of the inner liner tube 120, and the plurality of positioning bosses 124 are arranged at intervals along the axial direction of the inner liner tube 120. That is, the radial dimension of the outer surface of the inner liner tube 120 is relatively large in some areas, close to the inner diameter of the opening of the heat exchange tube 300 and / or the main steam tube plate 200, which serves to assemble, position and support the inner liner tube 120, and to impede the flow between the inner liner tube 120 and the heat exchange tube 300 and / or the main steam tube plate 200. Optionally, the positioning bosses 124 can be gaskets to ensure that the axis of the inner liner tube 120 is located at the centerline of the heat exchange tube 300.

[0068] See Figure 1 and Figure 4 As shown, in some possible embodiments, the liner tube 120 has a flared structure 122 on the side away from the main steam tube sheet 200 or the heat exchange tube 300 through which it passes. The radial dimension of the flared structure 122 is larger than the radial dimension of the liner tube 120. The flared structure 122 is inserted into the opening of the heat exchange tube 300 and / or the main steam tube sheet 200 to press the liner tube 120 against the heat exchange tube 300 and / or the main steam tube sheet 200. It can be understood that the liner tube 120 has a flared structure 122 on the inlet side near the heat exchange tube 300 or the main steam tube sheet 200. Figure 1 and Figure 4 The radial dimension of the outer surface of the part shown (left side) is larger than the inner diameter of the opening of the heat exchange tube 300 and the main steam tube plate 200, so that the inner liner tube 120 has radial clamping force and axial friction force with the heat exchange tube 300 or the main steam tube plate 200.

[0069] In some possible implementations, the flared structure 122 is provided with a slot 123, which extends axially along the inner liner tube to achieve a certain degree of elasticity in the end structure and improve the long-term effectiveness of the clamping force of the flared structure 122. It is understood that the flared structure 122 is provided with a slot 123, which extends axially along the inner liner tube 120. Where the radial dimension of the outer surface of the inner liner tube 120 near the inlet side of the heat exchange tube 300 or the main steam tube plate 200 is locally larger than the inner diameter of the opening of the heat exchange tube 300 and the main steam tube plate 200, and in its extended region, a slot 123 can be provided to reduce the stiffness of the local area, adjust the magnitude of the interaction force between the inner liner tube 120 and the heat exchange tube 300 or the main steam tube plate 200, and control the local stress level of the inner liner tube 120.

[0070] It should be noted that the inner diameter of the liner tube 120 can be reasonably selected according to actual engineering needs; it can be of equal diameter or variable diameter. The inner diameter of the liner tube 120 should be as large as possible to reduce the throttling effect at the steam outlet. The length of the liner tube 120 is adjustable, and the length of the liner tube inserted into the heat exchange tube and / or the opening of the main steam tube plate covers the entire thickness of the main steam tube plate. Preferably, the length of the liner tube 120 is such that the gap between the liner tube 120 and the opening of the heat exchange tube 300 or the main steam tube plate 200 covers the thickness of the main steam tube plate 200 as much as possible. The number of liner tubes 120 is consistent with the number of openings on the main steam tube plate 200 or the number of heat exchange tubes 300 connected to the main steam tube plate 200. In Embodiment 1 of this application, the outer surface of the liner tube 120 can be sprayed with a thermal barrier (insulation) coating, which can increase the thermal resistance between the steam and the heat exchange tube 300 and / or the main steam tube plate 200.

[0071] In some possible implementations, the mounting structure includes a support fixing plate 110 and a clamping cover plate 140.

[0072] Support plate 110, including opposing first surfaces ( Figure 1 and Figure 3 The image shows the right side and the second surface. Figure 1 and Figure 3 As shown in the diagram (left side), the first surface has multiple first stepped countersunk holes 111 extending to the second surface. The number and position of the first stepped countersunk holes 111 correspond to the number and position of the openings in the main steam tube sheet 200 or the heat exchange tubes 300. The inner liner tube 120 passes through the first stepped countersunk holes 111, and the support fixing plate 110 is used to connect with the main steam tube sheet 200. It is understood that the outer radial dimension (outer diameter radial dimension) of the portion of the inner liner tube 120 inserted into the opening of the heat exchange tube 300 or the main steam tube sheet 200 is smaller than the inner diameter of the opening of the heat exchange tube 300 or the main steam tube sheet 200, so as to form a gap between the inner liner tube 120 and the heat exchange tube 300 and the main steam tube sheet 200. The nominal size of the gap is half the difference between the inner diameter of the heat exchange tube 300 or the opening and the outer diameter of the inner liner tube 120. In actual engineering projects, the gap size can be reasonably selected according to the actual situation.

[0073] A clamping cover plate 140 is fixedly connected to the first surface of the support fixing plate 110. The clamping cover plate 140 is used to press the inner liner tube 120 into the first stepped countersunk hole 111. With the above arrangement, the inner liner tube 120 is fixed by the support fixing plate 110 and the clamping cover plate 140.

[0074] Further, a first stepped groove 115 is formed on the inner wall of the first stepped countersunk hole 111, and the first stepped groove 115 is located on one side of the first surface. A first stepped structure 121 is formed radially on the outer periphery of the liner tube 120. The first stepped structure 121 is engaged within the first stepped groove 115. The first stepped structure 121 cooperates with the first stepped groove 115, and the pressing cover plate 140 is used to press the first stepped structure 121 of the liner tube 120 into the first stepped groove 115. It can be understood that the liner tube 120 is located near the outlet side of the main steam tube sheet 200 or the heat exchange tube 300 (…). Figure 1 and Figure 3 The right side shown has a radial first stepped structure 121 for mounting in the first stepped countersunk hole 111 of the support plate 110.

[0075] Optionally, the heat exchange between the liner tube 120 and the steam is forced convection, while the heat exchange tube 120 and the inner wall of the opening in the heat exchange tube 300 or the main steam tube sheet 200 are mainly conductive and radiative heat exchange. The size of the gap can be reasonably selected according to the actual engineering needs. When installing the liner tube 120, the position of the liner tube inserted into the heat exchange tube and / or the opening in the main steam tube sheet is such that the liner tube is at the center of the heat exchange tube or the opening (ensuring the coaxiality of the liner tube installation), so as to ensure that the gap between the liner tube and the heat exchange tube and / or the opening is evenly distributed circumferentially. It is necessary to ensure that the centerline of the liner tube 120 coincides with the centerline of the heat exchange tube 300 or the opening as much as possible (ensuring the coaxiality of the two), so that the circumferential dimension of the gap is as uniform as possible. To further increase the thermal resistance between the steam and the heat exchange tube 300 and the main steam tube sheet 200, the inner liner tube 120 or the heat exchange tube 300 can be surface treated or additional structures can be added, such as spraying a thermal barrier (insulation) coating.

[0076] In some possible embodiments, the inner liner tube structure 100 further includes a first elastic member 130, sleeved on the inner liner tube 120 and located within the first stepped groove 115. One end of the first elastic member 130 abuts against the first stepped structure 121, and the other end abuts against the pressing cover plate 140. Thus, the first stepped structure 121 of the inner liner tube 120 and the first elastic member 130 are installed together in the first stepped groove 115 of the support fixing plate 110, and the pressing cover plate 140 compresses the first elastic member 130 to press the inner liner tube 120 into the first stepped countersunk hole 111. It is understood that the first stepped groove 115 is used for the installation of the first stepped structure 121 and the first elastic member 130 of the inner liner tube 120.

[0077] Understandably, the number of first elastic elements 130 corresponds to the number of inner liner tubes 120. The first elastic element 130 is fitted onto the outer circumference of the inner liner tube 120 and is installed together with the first stepped structure 121 of the inner liner tube 120 in the first stepped groove 115 structure of the support fixing plate 110, providing elastic force to press the inner liner tube 120 firmly into the first stepped countersunk hole 111 structure. Optionally, the first elastic element 130 can be a disc spring. The first elastic element 130 can be a single disc spring or a combination of multiple disc springs.

[0078] A clamping cover plate 140 is mounted on a support fixing plate 110 to press the first elastic element 130 into the first stepped countersunk hole 111 structure of the support fixing plate 110, providing elastic force to press the inner liner tube 120 firmly into the first stepped countersunk hole 111 structure. The clamping cover plate 140 has a certain thickness to provide sufficient rigidity to ensure that the first elastic element 130 is pressed into the support fixing plate 110.

[0079] See Figure 1 and Figure 5 As shown, in some possible embodiments, the outer edge of the support fixing plate 110 is provided with a support ring 112, and the support fixing plate 110 has a first fixing hole 113, the axial direction of the first fixing hole 113 being parallel to the axial direction of the first stepped countersunk hole 111. The inner liner structure 100 also includes a fastener 150, which passes through the first fixing hole 113 and is fixedly connected to the main steam pipe plate 200, thereby fixing the support fixing plate 110 to the main steam pipe plate 200. Optionally, the fastener 150 can be a bolt, and the first fixing hole 113 can be a smooth hole, through which the support fixing plate 110 is installed on the main steam pipe plate 200 using bolts. The support fixing plate 110 is connected to the main steam pipe plate 200 through the fastener 150 and other structures. The fastener 150 connecting the support fixing plate 110 and the main steam pipe plate 200 can be mechanically prevented from loosening by a single-ear locking washer. The support fixing plate 110 may have a certain thickness to ensure the rigidity of the support fixing plate 110. At the same time, it is preferable to limit the mass of the support fixing plate 110 to a range that can be operated by a single person, so as to facilitate on-site disassembly and assembly operations.

[0080] Understandably, the support ring 112 serves as the contact structure between the support fixing plate 110 and the main steam tube sheet 200, determining the gap between them and limiting flow. The support ring 112 may have local radial slots to drain any water that may accumulate between the support fixing plate 110 and the main steam tube sheet 200 during the two-phase shutdown process.

[0081] See Figure 1 and Figure 6As shown, in some possible embodiments, the support fixing plate 110 has a plurality of second fixing holes 114, the axial direction of the second fixing holes 114 being parallel to the axial direction of the first stepped countersunk hole 111. The support fixing plate 110 and the pressure cover plate 140 are fixedly connected by fasteners 150 passing through the pressure cover plate 140 and the second fixing holes 114. Optionally, the fastener 150 can be a bolt, the second fixing holes 114 can be threaded holes, and the pressure cover plate 140 is mounted on the support fixing plate 110 using bolts that engage with the threaded holes.

[0082] See Figure 2 and Figure 7 As shown, in some possible implementations, the support fixing plate 110 is formed by splicing together multiple sub-fixing plates 116. In this embodiment, there are two sub-fixing plates 116. It can be understood that the support fixing plate 110 can be a single plate structure or a spliced ​​structure, so as to facilitate the disassembly, fixing and maintenance of the support fixing plate 110.

[0083] The clamping cover plate 140 can also be assembled from multiple sub-cover plates. The clamping cover plate 140 is fixed to the support fixing plate 110 by fasteners 150. It can be understood that the clamping cover plate 140 can be a single plate structure or multiple clamping cover plates 140. The clamping cover plate 140 is preferably multiple clamping cover plates 140 to facilitate disassembly and assembly and structural maintenance.

[0084] The number of fasteners 150 corresponds to the number of the first fixing holes 113 and the second fixing holes 114. Fasteners 150 are used to fix the support fixing plate 110 to the main steam pipe plate and to fix the pressure cover plate 140 to the support fixing plate 110. Fasteners 150 may include anti-loosening structures such as single-eared locking washers used when connecting the support fixing plate 110 and the main steam pipe plate 200 to ensure the lateral displacement freedom between the support fixing plate 110 and the main steam pipe plate 200.

[0085] See Figure 1 , Figure 8 and Figure 9 As shown, in some possible embodiments, the liner tube 120 extends radially outward from the outer periphery of the second surface and has a mounting and positioning structure 126. Optionally, the mounting and positioning structure 126 is a stepped surface or a conical surface structure.

[0086] Understandably, the liner tube 120 is supported at the end of the heat exchange tube 300 (right end shown in the figure) or the secondary side surface of the main steam tube plate 200 (right end shown in the figure) by the mounting and positioning structure 126. The mounting and positioning structure 126 seals the gap between the liner tube 120 and the heat exchange tube 300 at the end, causing the steam flow rate in the gap to be stagnant or low. Preferably, the mounting and positioning structure 126 of the liner tube 120 is selected as a stepped surface or a conical surface structure. A gap is left between the liner tube 120 and the first stepped countersunk hole 111 on the support fixing plate 110. The mounting and positioning structure 126 can form a clamping force between the liner tube 120 and the end of the heat exchange tube 300 or the secondary side surface of the main steam tube plate 200, thus sealing the gap between the liner tube 120 and the heat exchange tube 300 at the end.

[0087] Optionally, a thermal barrier (insulating) coating may be sprayed onto the ends of the liner tube 120 and the heat exchange tube 300, or onto the secondary side surface of the main steam tube sheet 200, or even onto the entire outer surface of the liner tube 120, to increase the thermal resistance between the steam and the main steam tube sheet 200. The thermal barrier (insulating) coating is located in the steam stagnation zone, further enhancing the tolerance for coating detachment, allowing for replacement and cleaning during maintenance. Alternatively, the thermal barrier (insulating) coating may also be sprayed onto the inner surface of the openings of the heat exchange tube 300 or the main steam tube sheet 200 that mates with the liner tube 120, preferably, such as the inner surface of the openings of the main steam tube sheet 200 with internal welded connections.

[0088] See Figure 1 , Figure 10 and Figure 11 As shown, in some possible embodiments, the inner liner tube structure 100 further includes an inner liner tube fastening structure 160, which is sleeved on the outer periphery of the inner liner tube 120 extending from the second surface. One end of the inner liner tube fastening structure 160 is connected to the support fixing plate 110, and the other end is connected to the heat exchange tube 300 or the main steam tube sheet 200. Optionally, the inner liner tube fastening structure 160 may also be installed on the tube end of the heat exchange tube 300 or the main steam tube sheet 200.

[0089] The inner liner 120 is reliably fixed to the main steam tube sheet 200 or the heat exchange tube 300 by the inner liner fastening structure 160. A gap is provided between the inner liner 120 and the heat exchange tube 300, and the steam within the gap is impounded or kept at a low flow rate to increase the thermal resistance between the steam and the main steam tube sheet 200 and the heat exchange tube 300. Alternatively, the inner liner 120 or the heat exchange tube 300 can be surface-treated or have additional structures added, such as spraying a thermal barrier (insulation) coating, to further increase the thermal resistance between the steam and the main steam tube sheet 200 and enhance its wear resistance, lubrication, corrosion resistance, or insulation properties. In practice, the inner liner fastening structure 160 can be selected based on the connection between the heat exchange tube 300 and the main steam tube sheet 200. The inner liner fastening structure 160 can be used to independently fix a single inner liner 120 to eliminate mutual interference between fixing structures, or multiple inner liner 120s can be fixed as a whole. The fixing method can be permanent (such as welding, which is non-removable) or detachable (threaded connection or clamping structure). The specific fixing structure can be reasonably set according to the actual requirements of the specific project.

[0090] Understandably, the installation structure can be flexibly designed according to the actual engineering requirements. The installation structure can be either a detachable fixed structure or a permanent fixed structure. For detachable structures, a unified fixing method can be chosen to secure all inner liner tubes together, or a zoned fixing method can be chosen to divide the inner liner tubes into several areas and fix each area as a whole, or a single fixing method can be chosen to fix each inner liner tube individually. The entire installation structure is safe and reliable, and can meet the service requirements for long-term reliable operation at high temperatures. During operation, there will be no loosening, wear, or vibration of the inner liner tubes.

[0091] If the liner tubes do not require disassembly or reassembly during the entire operation period, a permanent fixing structure is preferred for the liner tubes. For ease of installation, partial or overall fixing structures are preferred. Permanent fixing structures are preferably welded or threaded with anti-loosening features. If in-service inspections of the heat exchanger tube bundle or the liner tubes are required during the entire operation period, the liner tubes should have a removable structure. For ease of disassembly and reassembly, partial or overall fixing structures are preferred. To facilitate localized in-service inspections of the heat exchanger tubes or liner tubes, localized fixing in sections is preferred. This fixing should be easy to install and remove and reliably secured.

[0092] In the gap formed between the inner liner tube 120 and the inner wall of the opening in the heat exchange tube 300 or the main steam tube sheet 200, the flow velocity of the heat transfer medium (such as steam) should be stagnant or as low as possible; the lower the flow velocity, the better the effect. Therefore, a reasonable flow-limiting structure can be set according to the actual situation. This flow-limiting structure can be an independent flow-limiting structure for each inner liner tube 120, or a unified flow-limiting structure for a portion or the entire inner liner tube 120. The inner liner tube fastening structure 160 should meet various requirements such as operation and testing. It is understood that the installation structure is fixed to the side of the inner liner tube closest to the main steam tube sheet, and the installation structure is pre-set with a reasonable flow-limiting or flow-blocking structure to reduce the flow velocity of the fluid in the gap and prevent or reduce axial flow of the fluid along the gap.

[0093] The stiffness of the inner liner is configured to prevent flow-induced vibration under the scouring of the internal fluid medium. When the flow velocity of the heat transfer medium inside the inner liner 120 is low and the stiffness of the inner liner 120 is high, it can be fixed at one end. For ease of structural design and installation, it is preferable to fix it on the side of the main steam tube sheet 200. When the flow velocity of the heat transfer medium inside the inner liner 120 is high and the stiffness of the inner liner 120 is low, it can be fixed at both ends. The section inserted into the heat exchange tube 300 can be designed as a spring structure to facilitate the insertion of the inner liner 120. At the same time, during the insertion process, care should be taken to avoid scratching the tube wall with the inner liner 120.

[0094] In some possible embodiments, the inner liner fastening structure 160 has a second stepped countersunk hole 161, and the inner wall of the second stepped countersunk hole 161 has a second stepped groove 162, which is located on the side away from the support fixing plate 110. The number and position of the second stepped countersunk holes 161 correspond to the number and position of the openings in the main steam pipe plate 200. The outer periphery of the inner liner 120 has a second stepped structure 125 formed radially, which engages with the second stepped groove 162. The second stepped structure 125 cooperates with the second stepped groove 162 to confine the inner liner 120 within the second stepped countersunk hole 161.

[0095] In some possible embodiments, the inner liner structure 100 further includes a second elastic member 163, sleeved on the inner liner 120 and located within the second stepped groove 162. One end of the second elastic member 163 abuts against the second stepped structure 125, and the other end abuts against the groove wall of the second stepped groove 162. The heat exchange tube 300 and the main steam tube sheet 200 can abut against the other end of the second stepped structure 125 opposite to the second elastic member 163, thereby compressing the inner liner 120 into the second stepped countersunk hole 161 through the compression of the second elastic member 163 by the second stepped structure 125. It is understood that the number of first elastic members 130 corresponds to the number of inner liner tubes 120.

[0096] In some possible implementations, the thickness of the first stepped countersunk hole 111 structure on the support plate 110 and the compression amount of the first elastic element 130 (the combined disc spring is the overall compression amount) are adjustable to limit the clamping force of the inner liner tube 120 within a certain range, accommodating manufacturing deviations and the evolution of the structure and mechanical state during operation; at the same time, the lateral friction force between the radial first step structure 121 and the first stepped countersunk hole 111 on the inner liner tube 120 is limited to a certain limit to avoid mechanical damage to the inner liner tube 120 by lateral shear or bending moment.

[0097] Optionally, the radial dimension of the first stepped countersunk hole 111 structure on the support fixing plate 110, the radial dimension of the first step structure 121 of the inner liner tube 120, and the major diameter dimension of the first elastic element 130 can be adjusted to accommodate the lateral displacement difference caused by the temperature difference between the support fixing plate 110 and the main steam pipe plate 200, and to avoid mechanical damage to the inner liner tube 120 by lateral shear or bending moment.

[0098] Optionally, the support fixing plate 110 and the clamping cover plate 140 are designed to be spliced ​​together, with each clamping cover plate 140 fixed only to one splicing plate of the support fixing plate 110, thus avoiding the influence of relative displacement between the splicing structures of the support fixing plate 110 on the clamping effect of the clamping cover plate 140. Alternatively, the clamping cover plate 140 and the support fixing plate 110 are designed to be spliced ​​together, with any splice seam of the support fixing plate 110 covered by the clamping cover plate 140, thereby enhancing the overall rigidity of the spliced ​​support fixing plate 110.

[0099] Optionally, the area near the first step structure 121 in the radial direction of the inner liner tube 120 may be locally thickened to reduce the local stress peak caused by transverse shear or bending moment to the inner liner tube 120 and avoid mechanical damage. The distance between the positioning boss 124 structure on the inner liner tube 120 and the first step structure 121 is adjustable to reduce the stress peak on the inner liner tube 120 and avoid damage to the inner liner tube 120.

[0100] Optionally, the number and position of the positioning bosses 124 on the inner liner 120 can be adjusted in conjunction with the thickness of the main steam tube sheet 200 and the main steam operating parameters to adjust the temperature distribution of the main steam tube sheet 200, reduce the stress peak of the main steam tube sheet 200, and improve the stress cycle characteristics. The number and position of the positioning bosses 124 on the inner liner 120 and the thickness of the inner liner 120 can be adjusted in conjunction with the thickness of the main steam tube sheet 200 and the main steam operating parameters to reduce the risk of flow-induced vibration.

[0101] Optionally, a partial flaring structure 122 may be added to the inner liner tube 120 at a location where the radial dimension of its outer surface near the inlet side of the main steam tube sheet 200 is larger than the inner diameter of the heat exchange tube 300. This prevents the end of the inner liner tube 120 from scratching the inner wall of the heat exchange tube and increases the insertion depth of the inner liner tube 120 into the heat exchange tube 300, reducing the impact of bends in the heat exchange tube 300. To improve the rigidity of the inner liner tube, a flaring structure is provided on the side of the inner liner tube that inserts into the opening of the main steam tube sheet or the heat exchange tube. The outer diameter of the flaring structure is slightly larger than the size of the opening of the main steam tube sheet or the heat exchange tube, achieving elastic fixation between the inner liner tube and the wall of the heat exchange tube or the inner wall of the opening of the main steam tube sheet, thereby improving the installation rigidity of the inner liner tube.

[0102] Optionally, the area near the root of the grooved region 123 of the inner liner tube 120 and the extension section towards the ungrooved region 123 can be locally thickened radially, with the thickened size close to the inner diameter of the heat exchange tube 300 to reduce local stress peaks and to act as a flow obstruction.

[0103] Optionally, the outer side of the inner liner 120, the first stepped countersunk hole 111 structure of the support fixing plate 110, and the support ring 112 of the support fixing plate 110 can be treated with surface treatment processes such as nitriding to reduce the friction coefficient between structures and improve the wear resistance of the structure.

[0104] Optionally, the difference between the inner diameter of the first fixing hole 113 on the support fixing plate 110 for connecting with the main steam pipe plate 200 and the major diameter of the fastener 150 is the maximum allowable sliding dimension between the support fixing plate 110 and the main steam pipe plate 200; this maximum sliding dimension is less than the lateral displacement limit corresponding to the radial dimension of the first stepped countersunk hole 111 structure on the support fixing plate 110, the radial dimension of the first step structure 121 of the inner liner tube 120, and the major diameter of the first elastic element 130.

[0105] Optionally, all the inner liner structures are designed for high-temperature environments, and appropriate high-temperature resistant alloys are selected based on the service temperature. The material of the inner liner 120 should be as consistent as possible with the material of the heat exchange tube 300, and the material of the support and fixing plate 110 should be as consistent as possible with the material of the main steam tube plate 200. The material of the first elastic element 130 is preferably 718 high-temperature resistant alloy. High-temperature resistant anti-galling solutions are selected for fasteners 150, such as molybdenum disulfide coating.

[0106] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A liner tube structure for a heat exchanger, characterized in that, The heat exchange device includes a main steam tube sheet, at least a portion of which has multiple openings and at least a portion of which contains heat exchange tubes; The inner liner structure includes: One or more inner liner tubes; The mounting structure is connected to the inner liner tube and is used to connect or weld to the main steam tube sheet to reliably fix the inner liner tube in the heat exchange tube and / or the opening of the main steam tube sheet. The inner liner is used to pass through the heat exchange tubes and / or openings in the main steam tube sheet, forming a gap between the inner liner and the heat exchange tubes and / or the openings. Within this gap, the fluid is stagnant or its velocity is less than 2 m / s, thereby increasing the thermal resistance between the steam and the heat exchange tubes or the main steam tube sheet; and / or The surface of the inner liner tube is provided with a heat-insulating coating or structure to increase the thermal resistance between the steam and the heat exchange tube and / or the main steam tube sheet.

2. The inner liner tube structure according to claim 1, characterized in that, The length of the lining tube inserted into the heat exchange tube and / or the opening in the main steam tube sheet covers the entire thickness of the main steam tube sheet.

3. The inner liner tube structure according to claim 1, characterized in that, The lining tube is inserted into the heat exchange tube and / or the opening in the main steam tube sheet such that the lining tube is located at the center of the heat exchange tube or the opening, so as to ensure that the gap between the lining tube and the heat exchange tube and / or the opening is uniformly distributed circumferentially.

4. The inner liner tube structure according to claim 1, characterized in that, The stiffness of the inner liner is configured to prevent flow-induced vibrations when the inner liner is subjected to the scouring of the internal fluid medium.

5. The inner liner structure according to claim 4, characterized in that, The liner tube is provided with a flared structure on the side where it is inserted into the opening of the main steam tube sheet or the opening of the heat exchange tube. The outer diameter of the flared structure is slightly larger than the size of the opening of the main steam tube sheet or the opening of the heat exchange tube, so as to realize the elastic fixation of the liner tube to the wall of the heat exchange tube or the inner wall of the opening of the main steam tube sheet, thereby improving the installation rigidity of the liner tube.

6. The inner liner structure according to claim 5, characterized in that, The flared structure is provided with a slot that extends axially along the inner liner tube to make the end structure elastic and improve the long-term effectiveness of the flared structure's clamping force.

7. The inner liner tube structure according to claim 1, characterized in that, The installation structure is a detachable fixing structure; all inner liner tubes can be fixed together as a whole; or the inner liner tubes can be divided into several areas and each area can be fixed as a whole; or each inner liner tube can be fixed individually; or The installation structure is a permanent, fixed structure.

8. The inner liner tube structure according to claim 7, characterized in that, The mounting structure is fixed to the side of the inner lining pipe near the main steam tube sheet. The mounting structure is pre-set with a reasonable flow limiting or flow blocking structure to reduce the flow velocity of the fluid in the gap and prevent or reduce the axial flow of the fluid along the gap.

9. The inner liner tube structure according to claim 1, characterized in that, The mounting structure includes: The support fixing plate includes a first surface and a second surface opposite to each other. The first surface has a plurality of first stepped countersunk holes that extend to the second surface. The inner lining tube passes through the first stepped countersunk holes. The support fixing plate is used to connect with the main steam tube sheet. A pressure cover plate is fixedly connected to the first surface, and the pressure cover plate is used to press the inner liner tube into the first stepped countersunk hole.

10. The inner liner tube structure according to claim 9, characterized in that, The inner wall of the first stepped countersunk hole is formed with a first stepped groove, which is located on one side of the first surface; The outer periphery of the inner liner tube has a first stepped structure formed radially, the first stepped structure is engaged in the first stepped groove, and the pressing cover plate is used to press the first stepped structure into the first stepped groove.

11. The inner liner tube structure according to claim 10, characterized in that, The installation structure further includes a first elastic element, which is sleeved on the inner liner tube and located in the first stepped groove. One end of the first elastic element abuts against the first stepped structure, and the other end abuts against the pressing cover plate.

12. The inner liner tube structure according to claim 9, characterized in that, The outer edge of the support fixing plate is provided with a support ring, and the support fixing plate is also provided with a first fixing hole, the axis of the first fixing hole being parallel to the axis of the first stepped countersunk hole. The mounting structure also includes fasteners for fixing the main steam tube sheet through the first fixing hole.

13. The inner liner tube structure according to claim 9, characterized in that, The support fixing plate is provided with a plurality of second fixing holes, the axial direction of the second fixing holes being parallel to the axial direction of the first stepped countersunk hole; The mounting structure also includes fasteners that pass through the clamping cover and are fixedly connected to the second fixing hole.

14. The inner liner tube structure according to claim 9, characterized in that, The support fixing plate is assembled from multiple sub-fixing plates; and / or The clamping cover is composed of multiple sub-covers joined together.

15. The inner liner tube structure according to claim 9, characterized in that, The lining tube extends outward from the second surface and has a radially formed mounting and positioning structure, which is used to limit the opening of the heat exchange tube or the main steam tube sheet.

16. The inner liner tube structure according to claim 15, characterized in that, The installation and positioning structure is a stepped surface structure or a conical surface structure.

17. The inner liner tube structure according to claim 1, characterized in that, The installation structure includes multiple inner liner tube fastening structures, which are sleeved on the outer periphery of the inner liner tube. The inner liner tube fastening structures are used to connect with the heat exchange tube or the main steam tube sheet.

18. The inner liner tube structure according to claim 17, characterized in that, The inner liner fastening structure has a second stepped countersunk hole, and the inner wall of the second stepped countersunk hole has a second stepped groove. The outer periphery of the inner liner tube has a second step structure formed radially, and the second step structure is engaged in the second stepped groove.

19. The inner liner tube structure according to claim 18, characterized in that, The installation structure further includes a second elastic element, which is sleeved on the inner liner tube and located in the second stepped groove. One end of the second elastic element abuts against the second stepped structure, and the other end abuts against the groove wall of the second stepped groove.

20. The inner liner tube structure according to claim 17, characterized in that, The multiple inner lining tube fastening structures are interconnected to form an integral structure.

21. A heat exchange device, characterized in that, include: The main steam tube sheet, multiple heat exchange tubes, and the inner lining tube structure as described in any one of claims 1-20, wherein the mounting structure is fixedly connected to the main steam tube sheet, and the main steam tube sheet has multiple openings, with at least a portion of the openings containing the heat exchange tubes; Wherein, at least a portion of the opening is perforated by the inner liner tube, and a gap is formed between the inner liner tube and the opening, wherein the fluid in the gap is stagnant or the fluid velocity is less than 2 m / s, so as to increase the thermal resistance between the steam and the main steam tube sheet; and / or At least a portion of the heat exchange tubes are perforated by the inner liner tube, and a gap is formed between the inner liner tube and the heat exchange tubes. The fluid within the gap is stagnant or has a velocity less than 2 m / s, thereby increasing the thermal resistance between the steam and the heat exchange tubes; and / or The surface of the inner liner tube is provided with a heat-insulating coating or structure to increase the thermal resistance between the steam and the heat exchange tube and / or the main steam tube sheet.

22. A heat exchange device, characterized in that, include: The main steam tube sheet and the inner lining tube structure as described in any one of claims 1-20, wherein the mounting structure is fixedly connected to the main steam tube sheet, and the main steam tube sheet is provided with a plurality of openings; Wherein, at least a portion of the opening is perforated by the inner liner tube, and a gap is formed between the inner liner tube and the opening, wherein the fluid in the gap is stagnant or the fluid velocity is less than 2 m / s, so as to increase the thermal resistance between the steam and the main steam tube sheet; and / or The surface of the inner liner tube is provided with a heat-insulating coating or structure to increase the thermal resistance between the steam and the heat exchange tube and / or the main steam tube sheet.

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