External air preheater for multi-stage tube bundle parallel tube box

Abstract

The utility model relates to the field of petrochemical engineering, in particular to an external air preheater for a multi-stage tube bundle parallel tube box, which comprises a plurality of tube bundles, a combustion-supporting air component and a shell component. The plurality of tube bundles are arranged in the shell assembly; the combustion-supporting air assembly comprises a combustion-supporting air inlet assembly and a combustion-supporting air outlet assembly which are arranged on the two faces of the shell assembly correspondingly and used for circulation of combustion-supporting air. The multiple pipe bundles are arranged between the combustion-supporting air inlet assembly and the combustion-supporting air outlet assembly in parallel and used for heating combustion-supporting air, and the multiple pipe bundles are connected with multiple heat sources correspondingly and used for adjusting the heat source flow according to the combustion-supporting air outlet temperature. Three heat sources of boiler blow-down water, deaerator emptying steam and saturated steam are used in parallel, the use amount of the heat sources can be reasonably adjusted according to the temperature of combustion-supporting air at an outlet of the air preheater, the requirements of clients for operation of system equipment in different seasons are met, waste heat of the heat sources is fully recycled, and the energy consumption of the system is reduced. And the purposes of energy conservation and consumption reduction are achieved.

Description

Technical Field

[0001] The utility model relates to the field of petrochemical industry, in particular to a multi-stage tube bundle parallel tube box external air preheater. Background Art

[0002] Directly using natural air as combustion air in systems such as syngas plants, catalytic cracking units, and hydrogen production plants in the petroleum and chemical industries not only results in significant fuel waste but also reduces furnace efficiency. Furthermore, using natural air as a cooling source in heat exchange can easily lead to severe acid dew point corrosion at the cooling source inlet of heat exchange equipment. Directly discharging high-temperature internal heat sources (such as boiler wastewater and deaerator vent steam) from these industries causes thermal pollution, creates a large amount of "white fog" in the winter, and results in energy waste. Using this air to heat the natural air to the required temperature for downstream equipment (such as burners and heat exchangers) can also lead to energy shortages.

[0003] Publication No.: CN106500126B A built-in air preheater and a CO boiler having the same include an air inlet header box, which is provided with an air inlet pipe; an air outlet header box, which is provided with an air outlet pipe and a plurality of heat exchange units, which are arranged side by side with each other and connected in parallel between the air inlet header box and the air outlet header box. Each heat exchange unit has a flat shape and includes a heat exchange tube bundle, which includes an air inlet tube box, an air outlet tube box and a plurality of flat heat exchange tubes connected between the air inlet tube box and the air outlet tube box. The plurality of flat heat exchange tubes are arranged in a row along the long side direction of their cross-section to obtain higher temperature combustion air, which can reduce the fuel consumption of the CO boiler and improve the furnace efficiency.

[0004] However, due to the large temperature differences in the northern region throughout the year, it is difficult to ensure the stability of the combustion air temperature at the air outlet when using a single heat source to heat the combustion air, which cannot meet the process requirements and is prone to acid dew corrosion.

[0005] Therefore, it is urgent to design an air preheater to meet the customer's needs for system equipment operation in different seasons, and to fully reuse the waste heat of the waste heat source to achieve the goal of energy saving and consumption reduction. Summary of the Invention

[0006] In view of this, the utility model aims to propose a multi-stage tube bundle parallel tube box external air preheater to meet the customer's needs for system equipment operation in different seasons, and to fully reuse the waste heat of the waste heat source to achieve the purpose of energy saving and consumption reduction.

[0007] The technical solution of the utility model is achieved as follows: a multi-stage tube bundle parallel tube box external air preheater, comprising multiple tube bundles, a combustion air assembly, a lower frame assembly and a shell assembly;

[0008] The plurality of tube bundles are arranged in the shell assembly, and the shell assembly is arranged on the lower frame assembly;

[0009] The combustion air assembly includes a combustion air inlet assembly and a combustion air outlet assembly, wherein the combustion air inlet assembly and the combustion air outlet assembly are respectively arranged on two sides of the shell assembly for the inflow and outflow of combustion air;

[0010] Multiple tube bundles are arranged in parallel between the combustion air inlet assembly and the combustion air outlet assembly, and are used to heat the circulating combustion air to a set temperature. Multiple tube bundles are respectively connected to multiple heat sources, and valves are provided between the tube bundles and the heat sources, which are used to adjust the heat source flow rate according to the combustion air temperature at the combustion air outlet assembly.

[0011] Furthermore, three tube bundles are provided, and the tube bundles include a first heat exchange tube bundle, a second heat exchange tube bundle and a third heat exchange tube bundle arranged in sequence, the first heat exchange tube bundle is connected to sewage, the second heat exchange tube bundle is connected to vent steam, and the third heat exchange tube bundle is connected to saturated steam.

[0012] Furthermore, the first heat exchange tube bundle is adjacent to the combustion-supporting air inlet assembly, and the third heat exchange tube bundle is adjacent to the combustion-supporting air outlet assembly.

[0013] Furthermore, the tube bundle includes multiple heat exchange tubes, and the multiple heat exchange tubes are one of a serpentine multi-flow flexible structure or a linear flow structure. The multiple heat exchange tubes are arranged in parallel in a single row or multiple rows, and the heat exchange tubes are one of a plain tube, a corrugated tube, an elliptical tube and a finned tube.

[0014] Furthermore, the inlet and outlet ends of the plurality of heat exchange tubes are respectively connected to a pipe box for collecting and distributing the fluid heat source.

[0015] Furthermore, the combustion air adopts one of the following methods: straight in from bottom and straight out from top, straight in from bottom and side out from top, side in from bottom and straight out from top, or side in from bottom and side out from top, and the heat medium adopts side in and side out.

[0016] Furthermore, a tripod is provided on the outside of the shell assembly, and the pipe box is provided on the tripod.

[0017] Furthermore, the shell assembly includes a shell plate, and a windshield is provided between the heat exchange tube and the shell plate.

[0018] Furthermore, the heat exchange tube is fixedly installed in the shell assembly through positioning clamps and support bars.

[0019] Furthermore, it also includes a control system and a temperature sensor, wherein the temperature sensor is used to detect the combustion air temperature at the combustion air inlet assembly and the combustion air outlet assembly, and the temperature sensor is connected to the control system.

[0020] Compared with the existing technology, the utility model has the following advantages:

[0021] 1. This utility model adopts three or more heat sources to heat the low-temperature combustion air in sequence through parallel tube bundles, and reasonably adjusts the amount of heat source according to the air temperature at the air preheater outlet, so as to meet the customer's needs for system equipment operation in different seasons. Saturated steam is not used under normal working conditions. When the temperature is low in winter, the amount of heat source is reasonably adjusted according to the air temperature at the air preheater outlet, and the waste heat of the heat source is fully reused to achieve the purpose of energy saving and consumption reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 This is the main view of the device structure of the utility model;

[0024] Figure 2 This is a left view of the device of the utility model;

[0025] Figure 3 This is a diagram of the housing assembly of the device of the utility model;

[0026] Figure 4 This is a schematic diagram of the heat source flow automatic control system of the utility model device.

[0027] Description of reference numerals:

[0028] 1. Tube bundle; 101. First heat exchange tube bundle; 102. Second heat exchange tube bundle; 103. Third heat exchange tube bundle; 104. Heat exchange tube; 2. Combustion air assembly; 201. Combustion air inlet assembly; 202. Combustion air outlet assembly; 3. Tube box; 4. Shell assembly; 401. Shell plate; 402. Lifting lug; 5. Wind shield; 6. Roof support; 7. Positioning card; 8. Tripod; 9. First heat exchange tube bundle inlet pipe; 10. First heat exchange tube bundle outlet pipe; 11. Second heat exchange tube bundle inlet pipe; 12. Second heat exchange tube bundle outlet pipe; 13. Third heat exchange tube bundle inlet pipe; 14. Third heat exchange tube bundle outlet pipe; 15. Second heat exchange tube bundle condensate discharge port; 16. Third heat exchange tube bundle condensate discharge port; 17. Lower frame assembly; 18. Temperature sensor; 19. Control system. DETAILED DESCRIPTION

[0029] In order to make the technical means, objectives and effects of the present invention easier to understand, embodiments of the present invention are described in detail below with reference to specific drawings.

[0030] It should be noted that all directional and positional terms in this utility model, such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," "center," etc., are used only to explain the relative positional relationships and connections between components in a specific state. They are intended solely to facilitate the description of this utility model and do not require that this utility model must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," etc., used in this utility model are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated.

[0031] In the description of this utility model, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0032] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0033] The utility model discloses a multi-stage tube bundle parallel tube box external air preheater, comprising a plurality of tube bundles 1, a combustion air assembly 2, a lower frame assembly 17 and a shell assembly 4;

[0034] A plurality of tube bundles 1 are arranged in a shell assembly 4, and the shell assembly 4 is arranged on the lower frame assembly 17;

[0035] The combustion air assembly 2 includes a combustion air inlet assembly 201 and a combustion air outlet assembly 202. The combustion air inlet assembly 201 and the combustion air outlet assembly 202 are respectively arranged on two sides of the shell assembly 4 for the inflow and outflow of combustion air.

[0036] Multiple tube bundles 1 are arranged in parallel between the combustion air inlet assembly 201 and the combustion air outlet assembly 202 for preheating the circulating combustion air. The inlets of the multiple tube bundles 1 are respectively connected to multiple heat sources. A valve is provided between the tube bundles 1 and the heat source for adjusting the heat source flow of the multiple tube bundles 1 according to the combustion air temperature at the combustion air outlet assembly 202.

[0037] The inlet of each tube bundle 1 is connected to a heat source. A valve is provided between the tube bundle 1 and the heat source for adjusting the heat source flow of the tube bundle 1 according to the temperature of the combustion air at the combustion air outlet assembly 202 to ensure that the combustion air reaches the set temperature. Increasing the temperature of the combustion air can not only reduce the demand for fuel and thus save energy, but also perform temperature regulation by multiple heat sources to avoid acid dew point corrosion caused by the combustion air temperature at the combustion air outlet assembly 202 being lower than the acid dew point when the temperature is low in winter, thereby extending the service life of the equipment.

[0038] This setup uses multiple heat sources to heat the low-temperature combustion air in sequence through the parallel tube bundle 1, and reasonably adjusts the amount of heat source according to the combustion air temperature at the combustion air outlet component 202, to meet the customer's needs for system equipment operation in different seasons, and to fully reuse the waste heat of the waste heat source, thereby achieving the purpose of energy saving and consumption reduction.

[0039] Preferably, at least two combustion air inlet assemblies 201 are provided, including multiple components such as an air inlet pipe, a regulating valve or baffle, a filter device, a guide vane, an insulation layer, a flange connection and a temperature sensor. The pipe cross-section of the combustion air inlet assembly 201 can be set to square, circular or other shapes.

[0040] This setting is combined together through a reasonable connection method to ensure that air can enter the air preheater at an appropriate speed and direction, thereby improving the heat exchange efficiency. Through careful design and installation, the combustion air inlet assembly 201 can effectively improve the working performance of the air preheater, extend the service life of the equipment, and reduce operating costs.

[0041] Specifically, three tube bundles 1 are provided, and the tube bundle 1 includes a first heat exchange tube bundle 101, a second heat exchange tube bundle 102 and a third heat exchange tube bundle 103 arranged in sequence. The first heat exchange tube bundle 101 is adjacent to the combustion air inlet assembly 201, and the third heat exchange tube bundle 103 is adjacent to the combustion air outlet assembly 202. The first heat exchange tube bundle 101 is connected to sewage, the second heat exchange tube bundle 102 is connected to vent steam, and the third heat exchange tube bundle 103 is connected to saturated steam.

[0042] The first heat exchange tube bundle 101 uses the waste heat of the sewage to preliminarily heat the combustion air, the second heat exchange tube bundle 102 uses the vent steam to further increase the temperature of the combustion air, and the third heat exchange tube bundle 103 uses saturated steam to heat the combustion air to the final target temperature; each section of the heat exchange tube bundle 1 uses a different heat source, and performs segmented heating according to the temperature and characteristics of the heat source. Through the three sequentially arranged heat exchange tube bundles 1, the combustion air can be heated step by step to finally reach the required target temperature; at the same time, through multi-stage heat exchange, the combustion air can be heated to a higher temperature, thereby improving the combustion efficiency. The heating effect can also be adjusted in real time according to the combustion air temperature at the combustion air outlet component 202 by controlling the heat source flow at the inlet of different heat exchange tube bundles 1.

[0043] This arrangement comprises three tube bundles 1, namely a first heat exchange tube bundle 101, a second heat exchange tube bundle 102 and a third heat exchange tube bundle 103. The multi-stage tube bundle 1 can flexibly adjust its working state according to actual needs to adapt to different working conditions. It can also achieve efficient step-by-step heating of the combustion air, fully utilize waste heat resources, improve energy utilization, enhance combustion efficiency, reduce emissions, extend equipment life, and has the advantages of flexible regulation and safety protection. This multi-stage tube bundle parallel tube box external air preheater is suitable for a variety of industrial applications and can effectively improve the overall performance of the combustion system.

[0044] Preferably, the first heat exchange tube bundle 101 , the second heat exchange tube bundle 102 and the third heat exchange tube bundle 103 are arranged in sequence from bottom to top.

[0045] Preferably, the second heat exchange tube bundle 102 further includes a second heat exchange tube bundle condensate discharge port 15 ; and the third heat exchange tube bundle 103 further includes a third heat exchange tube bundle condensate discharge port 16 .

[0046] This arrangement can effectively remove condensate or other liquids generated during the heat exchange process by adding a condensate drain port on the lower side of the outlet pipe box 3 of the second heat exchange tube bundle 102 and the third heat exchange tube bundle 103, thereby improving the heat exchange efficiency and reliability of the system. The condensate drain port can not only reduce internal corrosion and extend the service life of the equipment, but also improve safety and simplify maintenance work.

[0047] Specifically, the tube bundle 1 includes a plurality of heat exchange tubes 104 , which are either a serpentine multi-flow flexible structure or a linear flow structure. The plurality of heat exchange tubes 104 are arranged in parallel in a single row or multiple rows.

[0048] The serpentine multi-flow structure increases the heat exchange area and improves the heat exchange efficiency through multiple turns. The staggered row arrangement increases the turbulence of the fluid and improves the heat transfer coefficient. At the same time, the serpentine structure has a certain flexibility and can absorb thermal expansion and vibration, reducing stress accumulation. Single-row or multi-row arrangement can be selected according to actual needs to adapt to different space and flow requirements, facilitate maintenance and cleaning, and reduce maintenance costs. Multi-row arrangement can provide fault redundancy. Even if a single row of heat exchange tubes 104 has a problem, the other rows can continue to work. Select the sequential or staggered row arrangement according to the heat exchange requirements to improve the heat exchange uniformity and efficiency. The staggered row arrangement has a compact structure, which can improve the stability of the structure and make better use of limited space.

[0049] By employing a flexible, serpentine multi-flow structure or a linear flow structure, combined with a parallel single-row or multi-row arrangement, this configuration enables efficient heat exchange with excellent adaptability and reliability. This not only improves heat transfer efficiency, but also simplifies maintenance, reduces costs, and adapts to various operating conditions. Furthermore, through rational design and layout, the performance and efficiency of the heat exchange system can be maximized.

[0050] Specifically, the heat exchange tube 104 can be a plain tube, a corrugated tube, an elliptical tube, a finned tube, or the like.

[0051] Smooth tubes are suitable for general heat exchange occasions and provide basic heat exchange functions. Smooth tubes are relatively simple to process, low in cost, have a smooth surface, are easy to clean and maintain, and are suitable for a variety of working conditions, especially when no additional enhanced heat exchange is required.

[0052] The corrugated tube refers to a heat exchange tube 104 with a corrugated or node-like structure on the surface, which helps to increase the heat exchange area, increase the turbulence level, and enhance the heat exchange effect. The corrugated structure can also reduce dirt deposition and extend the service life of the heat exchanger.

[0053] An elliptical tube refers to a heat exchange tube 104 with an elliptical cross-section. It is suitable for occasions where specific fluid flow characteristics are required, such as when it is necessary to control the fluid velocity or distribution. The elliptical cross-section can optimize the fluid flow characteristics and improve the uniformity of heat exchange. Compared with circular tubes, elliptical tubes can reduce fluid resistance, reduce energy consumption, and make better use of space, especially when space is limited.

[0054] Finned tubes refer to heat exchange tubes 104 with fins on the surface. The fins greatly increase the heat exchange area and improve the heat exchange efficiency. The fins can also increase the turbulence of the fluid, further improving the heat exchange effect. They are suitable for high-temperature environments that require higher heat exchange efficiency.

[0055] This setting can achieve the best heat exchange effect according to the requirements of specific working conditions by selecting different types of heat exchange tubes 104, such as plain tubes, corrugated tubes, elliptical tubes and finned tubes, which helps to improve heat exchange efficiency, reduce maintenance costs, extend service life, and is suitable for different working environments, which can maximize the performance and economic benefits of the heat exchange system.

[0056] Specifically, the heat exchange tube 104 is made of corrosion-resistant, high-temperature-resistant, and thermally conductive stainless steel, carbon steel, alloy steel, etc., and is selected based on the customer's on-site operating conditions.

[0057] Stainless steel is suitable for occasions that require corrosion resistance and high temperature resistance. It has good corrosion resistance and is suitable for a variety of corrosive media. It is suitable for high temperature environments, is not easily oxidized, has good thermal conductivity, and is suitable for occasions that require efficient heat exchange.

[0058] Carbon steel has relatively low cost, is suitable for general working conditions, has high mechanical strength, good processing performance, and is easy to manufacture and weld.

[0059] Alloy steel is suitable for occasions requiring special properties such as high temperature resistance and corrosion resistance. It has good comprehensive performance, is both high temperature resistant and corrosion resistant, has good thermal conductivity, and is suitable for occasions requiring efficient heat exchange.

[0060] This setting can achieve the best heat exchange effect according to the requirements of specific working conditions by selecting different materials, such as stainless steel, carbon steel, and alloy steel. These heat exchange tube 104 materials each have unique advantages, which can improve heat exchange efficiency, reduce maintenance costs, extend service life, and are suitable for different working environments. Reasonable selection of the heat exchange tube 104 material can maximize the performance and economic benefits of the heat exchange system.

[0061] Specifically, the inlet and outlet ends of the plurality of heat exchange tubes 104 are respectively connected to a tube box 3 for collecting and distributing fluid.

[0062] The two pipe boxes 3 are respectively connected to the inlet and outlet ends of multiple heat exchange tubes 104, which play the role of collecting and distributing fluids, so that the fluids can be evenly distributed before entering the heat exchange tubes 104, thereby improving the heat transfer effect, ensuring good sealing, and reducing the risk of leakage.

[0063] Specifically, the first heat exchange tube bundle 101 is connected to the first heat exchange tube bundle inlet pipe 9 and the first heat exchange tube bundle outlet pipe 10; the second heat exchange tube bundle 102 is connected to the second heat exchange tube bundle inlet pipe 11 and the second heat exchange tube bundle outlet pipe 12; the third heat exchange tube bundle 103 is connected to the third heat exchange tube bundle inlet pipe 13 and the third heat exchange tube bundle outlet pipe 14; the first heat exchange tube bundle inlet pipe 9 is connected to the boiler sewage, the second heat exchange tube bundle inlet pipe 11 is connected to the deaerator vent steam, and the third heat exchange tube bundle inlet pipe 13 is connected to the saturated steam.

[0064] This arrangement introduces boiler wastewater, deaerator vent steam and saturated steam into different heat exchange tube bundles 1 for heat exchange through pipes, which can facilitate the connection of multiple heat sources and effectively reduce the overall size of the tube bundle 1, facilitate the installation, disassembly and maintenance of the tube bundle 1, and help reduce maintenance costs.

[0065] Specifically, the low-temperature combustion air can be supplied in straight from the bottom and out straight from the top, straight from the bottom and out from the side, from the bottom and out straight from the top, or from the bottom and out from the side. The heat medium can be supplied in side and out side. The inlet and outlet directions can be reasonably selected according to the site location and working conditions.

[0066] When the air enters directly from the bottom and exits directly from the top, the combustion air enters from the bottom center of the preheater and is discharged from the top center after heat exchange. It is suitable for occasions where the preheater needs to be arranged vertically. It can make full use of gravity to make the cold combustion air flow downward and the hot combustion air flow upward, which is beneficial to natural convection and improves heat exchange efficiency. The inlet and outlet positions are simple, which is easy to install and maintain. The vertical arrangement can also save horizontal space and is suitable for occasions with limited space.

[0067] When the air enters directly from the bottom and exits from the top side, the combustion air enters from the bottom center of the preheater and is discharged from the top side after heat exchange. This is suitable for situations where the preheater needs to be arranged vertically but the air outlet is not conveniently located at the top center. The position of the air outlet can be flexibly arranged to meet different installation requirements. The top side air outlet can make better use of space and avoid interference with other equipment.

[0068] When the air enters from the bottom and exits from the top, the combustion air enters from the bottom side of the preheater and is discharged from the top center after heat exchange. This is suitable for situations where the preheater needs to be arranged vertically but the air inlet is not conveniently arranged at the bottom center.

[0069] When the air enters from the bottom and exits from the top, the combustion air enters from the bottom side of the preheater and is discharged from the top side after heat exchange. This is suitable for situations where the preheater needs to be arranged vertically but it is inconvenient to arrange the air inlet and outlet at the bottom and top center positions.

[0070] This setting can achieve the best heat exchange effect according to the site location and working conditions by reasonably selecting the inlet and outlet directions of the combustion air and heat medium. It can not only improve the heat exchange efficiency, but also adapt to different installation requirements, simplify maintenance, improve the reliability and safety of the system, and maximize the performance and economic benefits of the air preheater.

[0071] Specifically, the pipe box 3 adopts a structure such as a round collecting pipe, a square pipe box, or a D-shaped pipe box, and is arranged outside the shell assembly 4 and supported by a tripod 8 arranged on the shell assembly 4 .

[0072] The circular manifold adopts a cylindrical manifold structure to ensure that the air intake of each tube bundle 1 is consistent, which helps to evenly distribute the hot fluid and improve the heat exchange efficiency. It has a simple structure, is easy to process and install, and can also reduce air flow resistance and energy consumption.

[0073] The square structure of the pipe box 3 can better adapt to the working conditions of being detachable and requiring regular maintenance throughout the year, and can arrange multiple rows of heat exchange tubes 104 in a single pass, which is convenient for welding the tube heads of the heat exchange tubes 104, improving the heat exchange efficiency, and having a compact structure, which can reduce the floor space.

[0074] The pipe box 3 adopts a D-shaped structure with one side being arc-shaped and the other side being flat. It can take into account the uniform distribution of the circular collecting pipes and the space utilization advantage of the square pipe box. The arc radius and plane size can be adjusted according to actual needs to adapt to different installation requirements. It can also reduce airflow resistance and improve heat exchange efficiency.

[0075] The pipe box 3 is arranged outside the shell assembly 4, which can save internal space and improve the overall compactness of the equipment. It is fixed to the shell assembly 4 through a tripod 8 to ensure the stability and safety of the pipe box 3.

[0076] The tripod 8 can provide stable support to ensure the stability of the pipe box 3 under various working conditions and during equipment transportation.

[0077] This configuration allows for optimal heat exchange performance based on site location and operating requirements. These pipe box 3 structures not only improve heat exchange efficiency but also adapt to varying installation requirements, simplify maintenance, and enhance system reliability and safety. They also facilitate welding of heat exchange tube 104 headers, reduce internal corrosion points, and facilitate subsequent maintenance. Furthermore, they reduce equipment size and save space.

[0078] Specifically, the shell assembly 4 includes a shell plate 401 , a shell frame and a lifting lug 402 . The shell plate 401 is used to close the shell frame. The lifting lug 402 is provided on the shell plate 401 and is used to lift the air preheater.

[0079] The shell plate 401 encloses the shell frame to form a complete shell, protecting the internal air preheater from the influence of the external environment, such as dust, moisture, corrosive substances, etc. The shell frame provides an installation basis for the shell plate 401 and provides the main structural support to ensure the stability and firmness of the shell assembly 4. It is hoisted through the lifting lug 402 to ensure the safety and reliability of the air preheater during the hoisting process. The shell plate 401 and the shell frame adopt a detachable connection method, which is easy to disassemble and assemble, and convenient for maintenance and inspection. It can also be fixed by welding.

[0080] This arrangement not only protects the air preheater from the influence of the external environment and improves its reliability and service life, but also facilitates the lifting and transportation of the air preheater through the design of the lifting lug 402, thereby improving the installation and maintenance efficiency of the equipment.

[0081] Specifically, a windshield 5 is provided between the heat exchange tube 104 and the shell plate 401 as needed. When the distance between the heat exchange tube 104 and the shell plate 401 is small, the windshield 5 may not be provided. The material and form of the windshield 5 may be selected according to the equipment structure and on-site working conditions.

[0082] The wind shield 5 can reduce the airflow directly passing through the gap between the heat exchange tube 104 and the shell plate 401, avoid airflow short circuit, and prevent the cold combustion air from being discharged directly through the combustion air outlet assembly 202 without being heated by the hot fluid of the heat exchange tube 104, thereby affecting the combustion air preheating effect. At the same time, by reasonably setting the wind shield 5, the "dead zone" where the airflow stagnates can also be reduced, thereby improving the heat exchange efficiency.

[0083] The windshield 5 can be made of stainless steel, aluminum alloy, galvanized steel, or fiberglass. Stainless steel is suitable for applications requiring corrosion resistance and high-temperature resistance. Aluminum alloy is suitable for applications requiring lightweight and corrosion resistance. Galvanized steel is suitable for general operating conditions, offers low cost, and offers good corrosion resistance. Fiberglass is suitable for non-high-temperature environments, offering excellent corrosion resistance and lightweight characteristics.

[0084] The windshield 5 may be in the form of a flat plate, a folded plate, a grille, an arc or a curve.

[0085] Flat plate type: Simple flat plate wind deflector is suitable for situations where the airflow direction is single.

[0086] Folding type: Folding windshield can change the direction of airflow through multiple layers of folding, which is suitable for situations where complex airflow distribution is required.

[0087] Grille type: Grille type wind deflectors can guide airflow through a grid structure and are suitable for situations where a larger ventilation area is required.

[0088] Curved or curved: Curved or curved wind deflectors can better guide airflow and are suitable for situations where optimized airflow distribution is required.

[0089] By rationally positioning the windshield 5 and selecting the appropriate material and form based on the equipment structure and on-site operating conditions, this configuration optimizes airflow distribution, improves heat exchange efficiency, and protects the equipment from mechanical stress and foreign matter. The windshield 5 not only enhances equipment performance and reliability, but also simplifies maintenance, improves safety, and adapts to diverse operating environments.

[0090] Specifically, the heat exchange tube 104 is fixedly installed in the shell assembly 4 through the positioning clamping plate 7 and the shelf support 6.

[0091] The positioning card plate 7 and the trellis support 6 ensure the accurate position of the heat exchange tube 104 in the shell assembly 4. The combined use of the positioning card plate 7 and the trellis support 6 can reduce the vibration of the equipment caused by airflow or thermal expansion and contraction during operation, reduce the noise during equipment operation, stably support the heat exchange tube 104, ensure its stability during operation, and quickly locate the position of the heat exchange tube 104, facilitate the installation, disassembly and reinstallation of the heat exchange tube 104, enhance the strength of the overall structure, improve the bearing capacity of the equipment, and relieve thermal stress caused by thermal expansion and contraction.

[0092] This arrangement, which secures the heat exchange tubes 104 using a combination of positioning clips 7 and slat supports 6, ensures the stability and reliability of the equipment, optimizes airflow distribution, improves heat exchange efficiency, and simplifies installation and maintenance. This approach not only improves equipment performance and service life, but also enhances safety and reduces maintenance costs.

[0093] Specifically, each process interface and pipeline connection can be bolted or welded. For example, the connection between the combustion air inlet assembly 201 and the shell assembly 4, the combustion air outlet assembly 202 and the shell assembly 4, the tube bundle 1 and the heat source, the combustion air inlet assembly 201 and the air duct, and the combustion air outlet assembly 202 and the air duct can all be connected by one or more of welding, bolting, riveting, etc.

[0094] This setting can achieve the best connection effect according to specific application requirements and working conditions by selecting bolt connection or welding structure. Bolt connection is suitable for occasions that require rapid disassembly, maintenance and adjustment, while welding structure is suitable for occasions that require high-strength connection and long-term stable operation. Reasonable selection of connection method can improve equipment performance and reliability, reduce maintenance costs, and ensure safe operation of the system.

[0095] Specifically, the interior of the housing assembly 4 is treated with appropriate anti-corrosion methods and materials according to the on-site working conditions. For example, the interior of the housing plate 401 may be treated with anti-corrosion treatment or painted.

[0096] This setting can achieve the best anti-corrosion effect according to the on-site working conditions by selecting appropriate anti-corrosion methods and materials. The anti-corrosion measures can not only improve the corrosion resistance and durability of the shell component 4, but also optimize the performance of the equipment, reduce maintenance costs, and improve safety. Reasonable selection of anti-corrosion methods and materials can ensure the long-term stable operation of the equipment and improve economic benefits.

[0097] Specifically, it also includes a control system 19 and a temperature sensor 18 . The temperature sensor 18 is used to detect the combustion air temperature at the combustion air inlet component 201 and the combustion air outlet component 202 . The temperature sensor 18 is connected to the control system 19 .

[0098] The control system 19 receives data from the temperature sensor 18 and adjusts the valve opening according to the set parameters to ensure that the combustion air temperature is within the predetermined range. It can be a PLC programmable logic controller, a DCS distributed control system, or other dedicated control system.

[0099] The temperature sensor 18 at the combustion air outlet assembly 202 can detect the temperature of the combustion air in real time and transmit the data to the control system. The temperature sensor 18 can be a thermocouple, a thermal resistor RTD, or an infrared temperature sensor, etc., selected based on measurement accuracy and response speed.

[0100] This setting is achieved by setting a valve between the tube bundle 1 and the heat source, and setting temperature sensors 18 at the combustion air inlet component 201 and the combustion air outlet component 202. The control system 19 can be used to achieve precise control of the combustion air temperature and heat source flow rate, so that it can adapt to various working conditions, meet the customer's needs for system equipment operation in different seasons, and improve the heat exchange efficiency and combustion efficiency of the equipment. This design not only ensures the stability of the combustion air temperature, but also extends the service life of the equipment, improves safety, simplifies the operating process, and reduces maintenance costs.

[0101] Example 1

[0102] Multi-stage tube bundle parallel tube box external air preheater

[0103] The combustion-supporting air inlet assembly 201 is provided with a combustion-supporting air inlet, the combustion-supporting air outlet assembly 202 is provided with a combustion-supporting air outlet, a first heat exchange tube bundle 101, a second heat exchange tube bundle 102, a third heat exchange tube bundle 103, a shell assembly 4, a lower frame assembly, a tripod 8, a first heat exchange tube bundle inlet pipe 9, a first heat exchange tube bundle outlet pipe 10, a second heat exchange tube bundle inlet pipe 11, a second heat exchange tube bundle outlet pipe 12, a third heat exchange tube bundle inlet pipe 13, a third heat exchange tube bundle outlet pipe 14, a boiler sewage inlet manifold, a boiler sewage outlet manifold, a deaerator vent steam inlet manifold, a deaerator vent steam outlet manifold, a saturated steam inlet manifold, a saturated steam outlet manifold, a second heat exchange tube bundle condensate discharge port 15, a third heat exchange tube bundle condensate discharge port 16, a positioning card plate 7, a shed support 6 and a wind shield 5.

[0104] Boiler sewage, deaerator vent steam and saturated steam enter the first heat exchange tube bundle 101, the second heat exchange tube bundle 102 and the third heat exchange tube bundle 103 from bottom to top through the first heat exchange tube bundle inlet pipe 9, the second heat exchange tube bundle inlet pipe 11 and the third heat exchange tube bundle inlet pipe 13 of the multi-stage tube bundle 1 respectively. Cold combustion-supporting air enters from the combustion-supporting air inlet assemblies 201 on the lower sides and exits from the combustion-supporting air outlet assembly 202 on the upper side. The second heat exchange tube bundle condensate discharge port 15 and the third heat exchange tube bundle condensate discharge port 16 are respectively provided on the lower sides of the deaerator vent steam outlet manifold and the saturated steam outlet manifold. The heat exchange tubes 104 of each stage of the tube bundle 1 are fixed to the internal frame of the shell assembly 4 through their positioning clamps 7 and slat supports 6, and the heat exchange tubes 104 are arranged in parallel in a single layer; wind shields 5 are provided between the heat exchange tubes 104 and the shell assembly 4 and on both sides above and below to prevent short circuit of cold combustion air; the pipe boxes 3 of all tube bundles 1 are arranged on the outside of the shell assembly 4 and supported by tripods 8; a lower frame assembly is provided on the lower side of the external air preheater of the multi-stage tube bundle parallel pipe box for fixing to the on-site foundation.

[0105] According to the changes in seasonal ambient temperature and the combustion air temperature at the air outlet, the inlet and outlet control valves of the first heat exchange tube bundle 101, the second heat exchange tube bundle 102 and the third heat exchange tube bundle 103 can be adjusted independently to meet the process requirements of the device equipment.

[0106] The shell assembly 4 is composed of a shell plate 401 , an inner frame of the shell assembly and a lifting lug 402 . The interior of the shell assembly 4 is provided with internal corrosion protection as required.

[0107] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-stage tube bundle parallel tube box external air preheater, characterized in that: It comprises a plurality of tube bundles (1), a combustion air assembly (2), a lower frame assembly (17) and a shell assembly (4); The plurality of tube bundles (1) are arranged in the shell assembly (4), and the shell assembly (4) is arranged on the lower frame assembly (17); The combustion air component (2) comprises a combustion air inlet component (201) and a combustion air outlet component (202), wherein the combustion air inlet component (201) and the combustion air outlet component (202) are respectively arranged on two surfaces of the housing component (4) for the inflow and outflow of combustion air; The plurality of tube bundles (1) are arranged in parallel between the combustion-supporting air inlet assembly (201) and the combustion-supporting air outlet assembly (202) for heating the circulating combustion-supporting air to a set temperature. The plurality of tube bundles (1) are respectively connected to a plurality of heat sources. A valve is provided between the tube bundle (1) and the heat source for adjusting the heat source flow rate according to the combustion-supporting air temperature at the combustion-supporting air outlet assembly (202).

2. The multi-stage tube bundle parallel tube box external air preheater according to claim 1, characterized in that: Three tube bundles (1) are provided, and the tube bundle (1) comprises a first heat exchange tube bundle (101), a second heat exchange tube bundle (102), and a third heat exchange tube bundle (103) which are provided in sequence. The first heat exchange tube bundle (101) is connected to sewage, the second heat exchange tube bundle (102) is connected to vent steam, and the third heat exchange tube bundle (103) is connected to saturated steam.

3. The multi-stage tube bundle parallel tube box external air preheater according to claim 2, characterized in that: The first heat exchange tube bundle (101) is adjacent to the combustion-supporting air inlet assembly (201), and the third heat exchange tube bundle (103) is adjacent to the combustion-supporting air outlet assembly (202).

4. The multi-stage tube bundle parallel tube box external air preheater according to claim 1, characterized in that: The tube bundle (1) comprises a plurality of heat exchange tubes (104), wherein the plurality of heat exchange tubes (104) are one of a serpentine multi-flow flexible structure or a linear flow structure, and the plurality of heat exchange tubes (104) are arranged in parallel in a single row or multiple rows, and the heat exchange tubes (104) are one of a plain tube, a corrugated tube, an elliptical tube and a finned tube.

5. The multi-stage tube bundle parallel tube box external air preheater according to claim 4, characterized in that: The inlet and outlet ends of the plurality of heat exchange tubes (104) are respectively connected to a tube box (3) for collecting and distributing fluid heat sources.

6. The multi-stage tube bundle parallel tube box external air preheater according to claim 5, characterized in that: A tripod (8) is provided on the outside of the housing assembly (4), and the pipe box (3) is provided on the tripod (8).

7. The multi-stage tube bundle parallel tube box external air preheater according to claim 1, characterized in that: The combustion air adopts one of the following methods: straight in from bottom and straight out from top, straight in from bottom and side out from top, side in from bottom and straight out from top, or side in from bottom and side out from top. The heat medium adopts the method of side in and side out.

8. The multi-stage tube bundle parallel tube box external air preheater according to claim 4, characterized in that: The shell assembly (4) comprises a shell plate (401), and a windshield (5) is provided between the heat exchange tube (104) and the shell plate (401).

9. The multi-stage tube bundle parallel tube box external air preheater according to claim 4, characterized in that: The heat exchange tube (104) is fixedly installed in the shell assembly (4) through a positioning clamp (7) and a shed bar support (6).

10. The multi-stage tube bundle parallel tube box external air preheater according to claim 1, characterized in that: The invention also includes a control system (19) and a temperature sensor (18), wherein the temperature sensor (18) is used to detect the combustion air temperature at the combustion air inlet component (201) and the combustion air outlet component (202), and the temperature sensor (18) is connected to the control system (19).

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