Heat exchanger for heating supplied air of boiler at extremely low air temperature
By employing vertically arranged heat exchange tube bundles and low-temperature resistant materials at extremely low temperatures, the problem of weld cracking caused by thermal stress in the heat exchanger was solved, enabling stable heating of the boiler air supply and ensuring normal operation and efficient heat exchange of the equipment at extremely low temperatures.
Patent Information
- Application Number
- CN202422545490.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2034-10-22
AI Technical Summary
At extremely low temperatures, conventional heat exchange devices suffer from weld cracking due to thermal stress, leading to equipment failure and difficulty in effectively heating boiler air to meet ignition requirements.
The heat exchange tube bundles are arranged vertically, the high-temperature steam inlet header and the condensate header are directly welded, the heat exchange tubes are connected to the frame, the heat exchange surface is increased, low-temperature resistant materials are used, and the header inlet/outlet is distributed along the circumference to reduce the welding area and improve structural strength and heat exchange efficiency.
It improves the operational stability and pressure resistance of the heat exchanger, avoids freezing, can heat air from -50℃ to above 21℃, improves the heat exchange effect, and solves the reliability problem of the equipment at extremely low temperatures.
Smart Images
Figure CN223663804U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to heat exchanger technical field especially a kind of heat exchanger of heating boiler air supply under extremely low temperature. BACKGROUND
[0002] Boiler burns coal, oil or natural gas, and air (oxygen) is needed for burning these fuels. The air temperature entering the boiler, i.e. the boiler air supply temperature, needs to meet certain requirements to successfully ignite. In some regions (such as parts of Russia), the ambient temperature can reach minus 50°C, or even lower. If air at such low temperatures is used directly for fuel combustion, it can cause problems such as failure to ignite or difficulty in igniting. Therefore, the extremely cold air must be heated to above 5°C before ignition can be successfully achieved.
[0003] In the prior art, a heat exchanger with high-temperature side steam can be used to heat the boiler air supply. However, conventional heat exchangers have the problem of freezing and failure due to low air temperature. Moreover, the heat exchange tubes of conventional heat exchangers are welded to the tube sheet at the high-temperature steam inlet end and the low-temperature drain outlet end, respectively, and the tube sheet is connected to the high-temperature steam header and the low-temperature drain header through a semicircular tube, and the tube sheet and the semicircular tube are angle-welded. At extremely low temperatures, high-temperature and high-pressure steam can generate a large temperature difference stress, which can easily cause the weld to crack and cause the equipment to fail. SUMMARY
[0004] To overcome the shortcomings of the prior art, the utility model provides a heat exchanger for heating boiler air supply at extremely low temperature, which aims to improve the structural strength of the heat exchanger and prevent failure caused by temperature difference stress.
[0005] The technical solutions adopted by the utility model are as follows:
[0006] A heat exchanger for heating boiler air supply at extremely low temperature, comprising a high-temperature steam inlet header, a heat exchange tube bundle, a drain header, and an air passage.
[0007] The high-temperature steam inlet header and the drain header are arranged in one or more groups above and below each other, and each group of the high-temperature steam inlet header and the drain header is provided with a group of heat exchange tube bundles.
[0008] Each group of heat exchange tube bundles comprises one or more columns of vertically arranged heat exchange tubes, and the multiple columns of heat exchange tubes are arranged in parallel.
[0009] The inlet of the top end of the heat exchange tube is connected to the outlet of the high-temperature steam inlet header, and the outlet of the bottom end of the heat exchange tube is connected to the inlet of the drain header.
[0010] The heat exchange tube bundle is fixedly arranged in a frame, and the frame is connected to the air passage on both sides.
[0011] The air passage is horizontally arranged, the air to be heated flows into the air passage from the air passage inlet, is heated by the heat exchange tube bundle, and then flows out from the air passage outlet.
[0012] Further technical solutions are as follows:
[0013] The high-temperature steam inlet header and the drain header are horizontally arranged respectively, and the header bodies are circular.
[0014] The outlet of the high-temperature steam inlet header is located on the side wall of the header body and is welded with the heat exchange tube.
[0015] The inlet of the drain header is located on the side wall of the header body and is welded with the heat exchange tube.
[0016] The heat exchange tubes in each column are arranged in parallel to form a symmetrical structure, and the symmetrical axis of the symmetrical structure coincides with the center line connecting the high-temperature steam inlet header and the drain header.
[0017] The outlet of the high-temperature steam inlet header is distributed along the circumferential direction of the circle, and the inlet of the drain header is distributed along the circumferential direction of the circle.
[0018] For the heat exchange tube bundle including one column of heat exchange tubes, the center line of the tube coincides with the center line connecting the high-temperature steam inlet header and the drain header.
[0019] The structure of the heat exchange tube includes a seamless steel tube, and the outer surface of the seamless steel tube is provided with an expanded heating surface, which is spirally wrapped along the axial direction of the seamless steel tube.
[0020] The expanded heating surface is welded on the outer surface of the heat exchange tube by using a steel belt.
[0021] The heat exchange tube bundle is welded with the frame.
[0022] The beneficial effects of the utility model are as follows:
[0023] Compared with the conventional horizontally arranged heat exchange tube, the heat exchange tube of the utility model is vertically arranged, so that the freezing condition of the heat exchange device is avoided, and the operation stability of the heat exchanger is improved.
[0024] Compared with the conventional structure that the heat exchange tube is welded with the tube plate, the tube plate is welded with the semicircular tube, and then the header is connected, the heat exchange tube of the utility model is directly welded with the inlet / outlet of the two-end header, which greatly improves the pressure resistance on one hand, and reduces the welding area and the welding operation steps on the other hand. Moreover, the header adopts a circular tube structure, the inlet / outlet is distributed along the circumference, and the strength of the connecting structure between the heat exchange tube and the header is improved, so that there is no great stress even under a large temperature difference.
[0025] The utility model discloses an extended heating surface improves the heat exchange power of the heat exchanger, improves the heat exchange effect, can heat -50 DEG C air to 21 DEG C or more.
[0026] Other features and advantages of the utility model will be set forth in the subsequent description, or be understood through the implementation of the utility model. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 It is the installation structure schematic drawing of three groups of heat exchange tube bundles of the utility model embodiment.
[0028] Figure 2 It is the horizontal section view of three groups of heat exchange tube bundles of the utility model embodiment.
[0029] Figure 3 It is the whole installation structure schematic drawing of the utility model embodiment.
[0030] Figure 4 It is the partial section view of heat exchange pipe of the utility model embodiment.
[0031] In the drawing: 1, high temperature steam import header tank, 2, drain header tank, 3, heat exchange pipe, 4, frame, 5, air channel, 6, extended heating surface, 7, symmetry axis. DETAILED DESCRIPTION
[0032] The specific implementation of the utility model will be explained below in combination with the drawings.
[0033] Participate Figures 1 to 3 The heat exchanger of the utility model embodiment under extremely low temperature heating boiler air supply, including high temperature steam import header tank 1, heat exchange tube bundle, drain header tank 2 and air channel 5,
[0034] High temperature steam import header tank 1 and drain header tank 2 are correspondingly arranged one or more groups above and below, and a group of heat exchange tube bundles is arranged between each group of high temperature steam import header tank 1 and drain header tank 2.
[0035] Each group of heat exchange tube bundles includes one or more columns of vertically arranged heat exchange pipes 3, and the multiple columns of heat exchange pipes 3 are arranged in parallel.
[0036] The top end inlet of heat exchange pipe 3 is connected with the outlet of high temperature steam import header tank 1, and the bottom end outlet of heat exchange pipe 3 is connected with the inlet of drain header tank 2.
[0037] The heat exchange tube bundle is fixedly arranged in frame 4, and the two sides of frame 4 are connected with air channel 5 respectively.
[0038] Air channel 5 is horizontally arranged, and the air to be heated flows into from the inlet of air channel 5, is heated by the heat exchange tube bundle, and then flows out from the outlet of air channel 5.
[0039] In the working process of the embodiment, high-temperature and high-pressure steam with a temperature of about 260℃ flows into the heat exchange tube bundle from the high-temperature steam inlet header 1, the high-temperature steam in the heat exchange tube bundle flows vertically from top to bottom, cold air with a temperature of about -50℃ and under normal pressure enters the air passage, exchanges heat with the high-temperature steam in the heat exchange tube bundle in the horizontal direction, and the medium after being cooled (167℃, 0.64MPa) enters the drain header 2, the air after being heated has a temperature of about 21℃, and is discharged from the air passage outlet for subsequent use in the boiler combustion.
[0040] The heat exchange tube bundle of the embodiment is vertically arranged, which avoids the ice freezing condition of several rows of tubes close to the lower part in the conventional horizontal arrangement of the tube bundle, and ensures the normal operation of the heat exchanger in the low-temperature environment.
[0041] The high-temperature steam inlet header 1 and the drain header 2 are horizontally arranged respectively, and the header bodies are circular.
[0042] The outlet of the high-temperature steam inlet header 1 is located on the side wall of the header body and is welded with the heat exchange tube 3.
[0043] The inlet of the drain header 2 is located on the side wall of the header body and is welded with the heat exchange tube 3.
[0044] As a specific embodiment, three groups of the high-temperature steam inlet header 1 and the drain header 2 are arranged correspondingly above and below, and one group of heat exchange tube bundle is arranged between each group of the high-temperature steam inlet header 1 and the drain header 2, and each group of heat exchange tube bundle includes two rows of heat exchange tubes. Correspondingly, two outlets of the high-temperature steam inlet header 1 are arranged along the circumferential direction of the circle, and two inlets of the drain header 2 are arranged along the circumferential direction of the circle. After the high-temperature steam enters the high-temperature steam inlet header, the high-temperature steam is discharged into two heat exchange tubes through the two radially arranged outlets, and then enters the corresponding drain header 2 through the two radially arranged inlets.
[0045] As a preferred embodiment, the two rows of heat exchange tubes 3 are arranged in parallel to form a symmetrical structure, and the symmetry axis 7 of the symmetrical structure coincides with the center line of the high-temperature steam inlet header 1 and the drain header 2.
[0046] The heat exchange tube bundle is directly welded with the upper and lower headers, and the symmetry axis coincides with the center line to realize "radial welding", and the strength of this structure is high, there is no large stress under large temperature difference, and the problems of weld cracking and equipment failure are effectively solved.
[0047] As an alternative to the above embodiment, a set of high-temperature steam inlet headers 1 and a set of drain headers 2 are arranged above and below each other, and a set of heat exchange tube bundles is arranged between the high-temperature steam inlet headers 1 and the drain headers 2, each set of heat exchange tube bundles comprising a row of heat exchange tubes, and in order to achieve the above high-strength structure, the tube center lines of the row of heat exchange tubes coincide with the center lines of the high-temperature steam inlet headers 1 and the drain headers 2, i.e. "radial welding" is performed.
[0048] participate Figure 4 The structure of the heat exchange tube 3 comprises a seamless steel tube, and the outer surface of the seamless steel tube is provided with an extended heating surface 6, which has helical fins that are helically arranged along the axial direction of the seamless steel tube. The distance between two adjacent helical fins in the axial direction is preferably 4.5 mm, the distance of the helical fins beyond the outer surface of the steel tube in the radial direction is 22 mm, and the thickness of the helical fins is 1.2 mm.
[0049] As an embodiment, the extended heating surface 6 is made of a steel strip with a size of 22X1.2 and is welded to the outer surface of the heat exchange tube 3.
[0050] The material of the tube and the extended heating surface can be a low-temperature resistant material (S30403) that can withstand a low temperature of -269°C.
[0051] The high-temperature steam exchanges heat with the cold air in the air passage through the outer surface of the steel tube and the extended heating surface. The light tube heat exchange area of the heat exchanger in this embodiment is 55m 2 , and after the extended heating surface is added, the heat exchange area reaches 955m 2 . The heat exchange area is greatly improved, thereby improving the heat exchange effect. Under the working condition of a steam consumption of 10000kg / h and an air flow of 216292Nm 3 , the heat exchange power can reach 5548KW.
[0052] Specifically, the heat exchange tube bundle is welded to the frame 4.
[0053] The utility model is suitable for heating air at extremely low temperature for use by other equipment, and solves the problems of freezing and failure due to low temperature and cracking of the weld.
[0054] Those skilled in the art can understand that the above description is only a preferred embodiment of the utility model, and is not used to limit the utility model, although the utility model has been described in detail with reference to the foregoing embodiment, and for those skilled in the art, the technical scheme recorded in the foregoing embodiment can be modified, or some technical features can be replaced equivalently. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. A heat exchanger for heating boiler air supply at extremely low temperatures, characterized in that, It includes a high-temperature steam inlet header (1), a heat exchange tube bundle, a condensate header (2), and an air duct (5); One or more sets of high-temperature steam inlet header (1) and condensate header (2) are provided on the upper and lower sides respectively, and a set of heat exchange tube bundles are provided between each set of high-temperature steam inlet header (1) and condensate header (2). Each heat exchange tube bundle includes one or more vertically arranged heat exchange tubes (3), and the multiple rows of heat exchange tubes (3) are arranged in parallel; The top inlet of the heat exchange tube (3) is connected to the outlet of the high-temperature steam inlet header (1), and the bottom outlet of the heat exchange tube (3) is connected to the inlet of the condensate header (2). The heat exchange tube bundle is fixedly installed in the frame (4), and the two sides of the frame (4) are respectively connected to the air duct (5); The air duct (5) is set horizontally. The air to be heated flows in from the inlet of the air duct (5), is heated by the heat exchange tube bundle, and then flows out from the outlet of the air duct (5). The high-temperature steam inlet header (1) and the condensate header (2) are respectively set horizontally, and both are circular. The outlet of the high-temperature steam inlet header (1) is located on the side wall of its body and is welded to the heat exchange tube (3); The inlet of the hydrophobic header (2) is located on the side wall of its body and is welded to the heat exchange tube (3); The heat exchange tubes (3) in each column are arranged in parallel to form a symmetrical structure. The axis of symmetry (7) of the symmetrical structure coincides with the center line connecting the high-temperature steam inlet header (1) and the condensate header (2).
2. The heat exchanger for heating boiler air supply at extremely low temperatures according to claim 1, characterized in that, The outlets of the high-temperature steam inlet header (1) are distributed along the circumference of the circle; the inlets of the hydrophobic header (2) are distributed along the circumference of the circle.
3. The heat exchanger for heating boiler air supply at extremely low temperatures according to claim 1, characterized in that, For a heat exchange tube bundle containing a row of heat exchange tubes (3), the center line of its tubes coincides with the center line connecting the high-temperature steam inlet header (1) and the condensate header (2).
4. The heat exchanger for heating boiler air supply at extremely low temperatures according to claim 1, characterized in that, The structure of the heat exchange tube (3) includes a seamless steel tube, and the outer surface of the seamless steel tube is provided with an extended heating surface (6), which is spirally surrounded along the axial direction of the seamless steel tube.
5. The heat exchanger for heating boiler air supply at extremely low temperatures according to claim 4, characterized in that, The extended heating surface (6) is welded to the outer surface of the heat exchange tube (3) using steel strips.
6. The heat exchanger for heating boiler air supply at extremely low temperatures according to claim 1, characterized in that, The heat exchange tube bundle is welded to the frame (4).