Energy-saving air preheater

Abstract

This invention relates to the field of air preheater technology and provides an energy-saving air preheater, including a preheating chamber, a flue gas inlet pipe, a flue gas outlet pipe, an air inlet, and an air outlet. The preheating chamber contains several main heat exchange tubes. The air flow direction within the preheating chamber is opposite to the flue gas flow direction within the main heat exchange tubes. Several flow control valves are evenly spaced on each main heat exchange tube, dividing it into multiple segments. An auxiliary heat exchange tube is located on the outer side of each segment, with a baffle installed at the inlet end of the auxiliary heat exchange tube. A flue gas thermometer is installed at the end of each segment of the main heat exchange tube, and an air thermometer is located on the outer side of each segment. This invention can monitor the temperature difference between the flue gas and the air at the same location in real time. When the difference exceeds a preset value, the flow rate of flue gas exiting that segment decreases, the baffle opens, and some flue gas enters the auxiliary heat exchange tubes from the main heat exchange tubes. Furthermore, with more heat exchange tubes, the heat exchange effect is improved.

Description

Technical Field

[0001] This invention relates to the field of air preheater technology, specifically to an energy-saving air preheater. Background Technology

[0002] Air preheaters are key equipment in boiler systems for improving thermal efficiency. Their core function is to recover waste heat from flue gas to heat combustion air, thereby reducing exhaust losses, enhancing the combustion process, and achieving energy savings. Currently, mainstream air preheaters generally employ a densely arranged heat exchange tube structure to enhance heat transfer by increasing the heat exchange area. However, this design faces the following technical bottlenecks in actual operation:

[0003] The number of heat exchange tubes in a traditional air preheater is fixed and lacks adaptability. The number of heat exchange tubes is determined during the equipment design phase and cannot be dynamically adjusted according to actual operating conditions. When the boiler is operating at low load or the fuel has a low calorific value and the flue gas temperature is insufficient, the heat exchange tubes cannot fully absorb heat, resulting in poor air preheating. Furthermore, when the flue gas passes through a large number of heat exchange tubes, the flow velocity is slow, the heat transfer coefficient decreases, and the overall heat exchange efficiency is reduced. Summary of the Invention

[0004] The purpose of this invention is to provide an energy-saving air preheater, which aims to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an energy-saving air preheater, comprising a preheating chamber, an inlet pipe, an outlet pipe, an air inlet, and an air outlet. The preheating chamber contains several main heat exchange tubes, with both ends connected to the inlet and outlet pipes respectively. The air flow direction within the preheating chamber is opposite to the flue gas flow direction within the main heat exchange tubes. Several flow control valves are evenly spaced on each main heat exchange tube, dividing it into multiple segments. An auxiliary heat exchange tube is located on the outer side of each segment, with both ends connected to the corresponding ends of the main heat exchange tube. A baffle is installed at the inlet of the auxiliary heat exchange tube. When the internal air pressure of the corresponding main heat exchange tube exceeds a certain value, the baffle automatically opens. A flue gas thermometer is installed at the end of each segment of the main heat exchange tube, and an air thermometer is installed on the outer side of each segment of the main heat exchange tube, both of which are installed inside the preheating chamber.

[0006] As a further embodiment of the present invention, the energy-saving air preheater also includes a controller, which is used to control the flow control valve, a flue gas thermometer is used to measure the flue gas temperature and transmit the flue gas temperature to the controller, an air thermometer is used to measure the air temperature and transmit the air temperature to the controller, and the controller is used to calculate the difference between the flue gas temperature and the air temperature corresponding to each section of the main heat exchange tube, and adjust the flow control valve according to the difference.

[0007] As a further embodiment of the present invention, the auxiliary heat exchange tube is V-shaped, one end of the baffle is hinged to the inner wall of the auxiliary heat exchange tube, the outer side of the baffle is connected to the inner wall of the auxiliary heat exchange tube by a tension spring, and a limit block is provided at the input end of the auxiliary heat exchange tube. When the baffle is closed, the limit block contacts the baffle.

[0008] As a further embodiment of the present invention, a one-way valve is installed at the output end of the auxiliary heat exchange tube, allowing only flue gas to flow out from the output end of the auxiliary heat exchange tube.

[0009] As a further embodiment of the present invention, a filter assembly is installed on the smoke inlet pipe. The filter assembly includes a rotating column, a ring, and a filter screen. Several rings are arranged in a circumferential array about the rotating column. One end of the rotating column is connected to a handle, and the other end of the rotating column is rotatably connected to the preheating box. The filter screen is installed in the ring. The ring and the rotating column are connected by a movable plate. A notch is provided on the smoke inlet pipe, and the ring is adapted to the notch.

[0010] As a further embodiment of the present invention, annular holes are provided on the two end faces of the ring, a sealing ring is movably installed on the outer end of the annular hole, a through groove is provided on the outer side of the ring, a pair of movable plates are slidably connected to the inner wall of the through groove, the sealing ring is connected to the movable plate through a connecting plate, the pair of movable plates are connected through a return spring, a sliding groove is provided on the surface of the rotating column, and the end of the movable plate is slidably connected to the sliding groove.

[0011] As a further embodiment of the present invention, a pair of triangular prisms are fixedly provided on both sides of the notch. When a ring is installed in the notch, the inclined surface on the triangular prism contacts the moving plate. When the ring is replaced, the inclined surface will squeeze the moving plate, causing the pair of moving plates to move closer to each other, thereby causing the sealing ring to shrink into the annular hole.

[0012] As a further embodiment of the present invention, the inlet pipe is connected to several main heat exchange tubes through a first distributor, and the outlet pipe is connected to several main heat exchange tubes through a second distributor. Both the inlet pipe and the outlet pipe pass through the preheating box and are fixedly connected to the preheating box.

[0013] In summary, the beneficial effects of this invention are:

[0014] By ensuring the airflow direction is opposite to the flue gas flow direction, the flue gas temperature at the same section of the main heat exchanger tube is consistently higher than the air temperature, enabling continuous and efficient heating of the air. The actual number of heat exchanger tubes used can be adjusted by installing auxiliary heat exchanger tubes, flow control valves, flue gas thermometers, air thermometers, and baffles. By monitoring the temperature difference between the flue gas and air at the same location, when the difference exceeds a preset value, the flow control valve is adjusted to reduce the flue gas flow rate out of that section, the baffles open, and some flue gas enters the auxiliary heat exchanger tubes from the main heat exchanger tubes. This slows the flue gas flow rate, increases the number of heat exchanger tubes, and improves the heat exchange effect, fully utilizing the high-temperature flue gas and increasing energy efficiency. When the difference is less than the preset value, the flow control valve is adjusted to increase the flue gas flow rate out of that section, allowing the insufficiently heated flue gas to quickly pass through the main heat exchanger tubes, thus improving heat exchange efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0016] Figure 1 This is a three-dimensional structural diagram of an energy-saving air preheater according to an embodiment of the present invention. Figure 1 .

[0017] Figure 2 This is a schematic diagram of the internal three-dimensional structure of an energy-saving air preheater according to an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the internal front structure of an energy-saving air preheater according to an embodiment of the present invention.

[0019] Figure 4 for Figure 3 A magnified view of a portion of point B in the middle.

[0020] Figure 5 This is a three-dimensional structural diagram of an energy-saving air preheater according to an embodiment of the present invention. Figure 2 .

[0021] Figure 6 for Figure 2 A magnified view of a portion of point A in the middle.

[0022] Figure 7 This is a schematic diagram of the structure of a filter component in an energy-saving air preheater according to an embodiment of the present invention.

[0023] Figure 8This is a schematic diagram of the internal structure of a filter assembly in an energy-saving air preheater according to an embodiment of the present invention.

[0024] Reference numerals in the attached drawings: 1-Preheating chamber, 2-Inlet pipe, 3-Outlet pipe, 4-Inlet, 5-Outlet, 6-Filter assembly, 7-First distributor, 8-Second distributor, 9-Main heat exchanger tube, 10-Auxiliary heat exchanger tube, 11-Flow control valve, 12-Flue gas thermometer, 13-Air thermometer, 14-Tension spring, 15-Baffle, 16-Limit block, 60-Through groove, 61-Sleeve, 62-Sealing ring, 63-Rotating column, 64-Handle, 65-Filter screen, 66-Moving plate, 67-Reset spring, 68-Triangular prism, 69-Slide groove, 70-Annular hole. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0027] Please see Figures 1 to 5This invention provides an energy-saving air preheater, comprising a preheating chamber 1, an inlet pipe 2, an outlet pipe 3, an air inlet 4, and an air outlet 5. Boiler tail flue gas enters the preheating chamber 1 through the inlet pipe 2, and air enters the preheating chamber 1 through the air inlet 4. The air inlet 4 and the air outlet 5 are respectively located on both sides of the preheating chamber 1. The preheating chamber 1 contains several main heat exchange tubes 9, which are parallel to each other. The two ends of each main heat exchange tube 9 are connected to the inlet pipe 2 and the outlet pipe 3, respectively. The inlet pipe 2 is connected to the several main heat exchange tubes 9 via a first distributor 7, and the outlet pipe 3 is connected to the several main heat exchange tubes 9 via a second distributor 8. Both the inlet pipe 2 and the outlet pipe 3 penetrate the preheating chamber 1 and are fixedly connected to it. The air flows in the preheating chamber 1 in the opposite direction to the flue gas flows in the main heat exchange tube 9. For example, the flue gas flows from left to right, and the air flows from right to left. It is easy to understand that the flue gas at the leftmost end is hotter than the flue gas at the rightmost end, and the air at the leftmost end is also hotter than the air at the rightmost end. In this way, the flue gas temperature at the same section of the main heat exchange tube 9 is always higher than the air temperature, ensuring that the air can be continuously heated. Several flow control valves 11 are evenly installed on each main heat exchange tube 9. The flow control valves 11 divide the main heat exchange tube 9 into multiple segments. An auxiliary heat exchange tube 10 is provided on the outside of each segment of the main heat exchange tube 9. The two ends of the auxiliary heat exchange tube 10 are connected to the two ends of the corresponding segment of the main heat exchange tube 9. A baffle 15 is installed at the input end of the auxiliary heat exchange tube 10. When the internal air pressure of the corresponding segment of the main heat exchange tube 9 is higher than a certain value, the baffle 15 automatically opens, and the flue gas can enter the auxiliary heat exchange tube 10 from the main heat exchange tube 9. A flue gas thermometer 12 is installed at the end of each segment of the main heat exchange tube 9. An air thermometer 13 is provided on the outside of each segment of the main heat exchange tube 9. The air thermometer 13 is installed on the inner wall of the preheating box 1.

[0028] In this embodiment of the invention, the energy-saving air preheater further includes a controller. The controller is used to control the flow control valve 11. The controller is electrically connected to the flue gas thermometer 12 and the air thermometer 13. The flue gas thermometer 12 is used to measure the flue gas temperature and transmit the flue gas temperature to the controller. The air thermometer 13 is used to measure the air temperature and transmit the air temperature to the controller. The controller is used to calculate the difference between the flue gas temperature and the air temperature corresponding to each section of the main heat exchange tube 9, and adjust the flow control valve 11 according to the difference. When the difference between the flue gas temperature and the air temperature is greater than a preset value, which is determined in advance according to actual needs, it indicates that the flue gas still has high value and can heat the outside air well. At this time, the flow control valve 11 of that section will be adjusted, so that the flow rate of the flue gas flowing out of that section will decrease. The high-temperature flue gas will accumulate in the main heat exchange tube 9, the internal air pressure will increase, and the baffle 15 will open. The flue gas will enter the auxiliary heat exchange tube 10 from the main heat exchange tube 9. In this way, there are more heat exchange tubes, the heat exchange effect is better, and the high-temperature flue gas is fully utilized. When the temperature difference between the flue gas and the air is less than the preset value, the temperature difference is very small, indicating that the flue gas cannot heat the outside air well. At this time, the flow control valve 11 of this section will be adjusted to increase the flow rate of the flue gas out of this section, so that the flue gas can quickly pass through the main heat exchange tube 9 to improve the heat exchange efficiency. At this time, the internal air pressure is insufficient to open the baffle 15, and the flue gas will flow through the main heat exchange tube 9 quickly.

[0029] In this embodiment of the invention, the auxiliary heat exchanger tube 10 is V-shaped. One end of the baffle 15 is hinged to the inner wall of the auxiliary heat exchanger tube 10. The outer side of the baffle 15 is connected to the inner wall of the auxiliary heat exchanger tube 10 by a tension spring 14. A limit block 16 is provided at the input end of the auxiliary heat exchanger tube 10. When the baffle 15 is closed, the limit block 16 contacts the baffle 15, and the limit block 16 is used to limit the baffle 15. A one-way valve is installed at the output end of the auxiliary heat exchanger tube 10, allowing only flue gas to flow out and not allowing flue gas to flow in.

[0030] Please see Figures 1 to 8 In this embodiment of the invention, a filter assembly is installed on the flue gas inlet pipe 2. The filter assembly includes a rotating column 63, a sleeve 61, and a filter screen 65. Several sleeves 61 are arranged in a circumferential array about the rotating column 63. One end of the rotating column 63 is connected to a handle 64, and the other end of the rotating column 63 is rotatably connected to the preheating chamber 1. The filter screen 65 is installed in the sleeve 61. The sleeve 61 and the rotating column 63 are connected by a moving plate 66. A notch is provided on the flue gas inlet pipe 2, and the sleeve 61 is adapted to the notch. By placing the sleeve 61 into the notch, impurities in the flue gas can be filtered. The filter screen 65 can be replaced by rotating the rotating column 63 by the handle 64 without affecting the normal use of the air preheater.

[0031] In this embodiment of the invention, annular holes 70 are provided on both end faces of the sleeve 61, and a sealing ring 62 is movably installed on the outer end of the annular hole 70. A through groove 60 is provided on the outer side of the sleeve 61, and a pair of movable plates 66 are slidably connected to the inner wall of the through groove 60. The sealing ring 62 is connected to the movable plate 66 through a connecting plate, and the pair of movable plates 66 are connected through a return spring 67. A sliding groove 69 is provided on the surface of the rotating column 63, and the end of the movable plate 66 is slidably connected to the sliding groove 69. With the sealing ring 62, the connection between the sleeve 61 and the notch is tighter, preventing smoke leakage.

[0032] In this embodiment of the invention, a pair of triangular prisms 68 are fixedly provided on both sides of the notch. The triangular prisms 68 are fixedly connected to the smoke inlet pipe 2 through a connecting rod. When a ring 61 is installed in the notch, the inclined surface on the triangular prism 68 contacts the moving plate 66. When the ring 61 is replaced, the inclined surface will squeeze the moving plate 66, causing the pair of moving plates 66 to move closer to each other, thereby causing the sealing ring 62 to shrink into the annular hole 70. In this way, when the ring 61 is replaced, wear between the sealing ring 62 and the notch is avoided, ensuring subsequent sealing performance.

[0033] The working process of this invention embodiment is as follows: During use, the flue gas from the boiler tail end enters the preheating chamber 1 from the inlet pipe 2, then enters the heat exchange tubes, and finally exits from the outlet pipe 3; air enters the preheating chamber 1 from the inlet 4, is heated by the heat exchange tubes, and then exits from the outlet 5. It is worth mentioning that the air flow direction in the preheating chamber 1 is opposite to the flue gas flow direction in the main heat exchange tube 9, ensuring that the flue gas temperature at the same section of the main heat exchange tube 9 is always higher than the air temperature, enabling continuous and efficient heating of the air. Furthermore, when the temperature difference between the flue gas and the air in the same section exceeds a preset value, the flow control valve 11 of that section will be automatically adjusted, reducing the flow rate of the flue gas exiting that section and causing the baffle 15 to open, allowing the flue gas to enter the auxiliary heat exchange tube 10 from the main heat exchange tube 9. This results in more heat exchange tubes, better heat exchange effect, and full utilization of the high-temperature flue gas. When the difference between the flue gas temperature and the air temperature is less than the preset value, the flow control valve 11 of that section will be adjusted to increase the flow rate of the flue gas flowing out of that section, so that the flue gas can quickly pass through the main heat exchange tube 9 to improve the heat exchange efficiency.

[0034] While several embodiments and examples of the present invention have been described for those skilled in the art, these embodiments and examples are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

[0035] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An energy-saving air preheater, comprising a preheating chamber (1), an inlet pipe (2), an outlet pipe (3), an air inlet (4), and an air outlet (5), wherein the preheating chamber (1) is provided with a plurality of main heat exchange tubes (9), the two ends of which are respectively connected to the inlet pipe (2) and the outlet pipe (3), characterized in that, The air flow direction in the preheating chamber (1) is opposite to the flue gas flow direction in the main heat exchange tube (9). Several flow control valves (11) are installed at equal intervals in each main heat exchange tube (9). The flow control valves (11) divide the main heat exchange tube (9) into multiple segments. An auxiliary heat exchange tube (10) is provided on the outside of each segment of the main heat exchange tube (9). The two ends of the auxiliary heat exchange tube (10) are connected to the two ends of the corresponding segment of the main heat exchange tube (9). A baffle (15) is installed at the inlet end of the auxiliary heat exchange tube (10). When the internal air pressure of the corresponding segment of the main heat exchange tube (9) is higher than a certain value, the baffle (15) opens automatically. At the end of each segment of the main heat exchange tube (9) A flue gas thermometer (12) is installed, and an air thermometer (13) is installed on the outside of each section of the main heat exchange tube (9). The air thermometer (13) is installed inside the preheating box (1). The energy-saving air preheater also includes a controller. The controller is used to control the flow control valve (11). The flue gas thermometer (12) is used to measure the flue gas temperature and transmit the flue gas temperature to the controller. The air thermometer (13) is used to measure the air temperature and transmit the air temperature to the controller. The controller is used to calculate the difference between the flue gas temperature and the air temperature corresponding to each section of the main heat exchange tube (9) and adjust the flow control valve (11) according to the difference.

2. The energy-saving air preheater according to claim 1, characterized in that, The auxiliary heat exchange tube (10) is V-shaped. One end of the baffle (15) is hinged to the inner wall of the auxiliary heat exchange tube (10). The outer side of the baffle (15) is connected to the inner wall of the auxiliary heat exchange tube (10) by a tension spring (14). A limit block (16) is provided at the input end of the auxiliary heat exchange tube (10). When the baffle (15) is closed, the limit block (16) contacts the baffle (15).

3. The energy-saving air preheater according to claim 1, characterized in that, A one-way valve is installed at the output end of the auxiliary heat exchange tube (10), and only flue gas is allowed to flow out from the output end of the auxiliary heat exchange tube (10).

4. The energy-saving air preheater according to claim 1, characterized in that, A filter assembly is installed on the smoke inlet pipe (2). The filter assembly includes a rotating column (63), a ring (61), and a filter screen (65). Several rings (61) are arranged in a circular array about the rotating column (63). One end of the rotating column (63) is connected to a handle (64), and the other end of the rotating column (63) is rotatably connected to the preheating box (1). The filter screen (65) is installed in the ring (61). The ring (61) and the rotating column (63) are connected by a moving plate (66). A notch is provided on the smoke inlet pipe (2), and the ring (61) is adapted to the notch.

5. The energy-saving air preheater according to claim 4, characterized in that, The two end faces of the ring (61) are provided with annular holes (70), and a sealing ring (62) is movably installed on the outer end of the annular hole (70). The outer side of the ring (61) is provided with a through groove (60). A pair of movable plates (66) are slidably connected to the inner wall of the through groove (60). The sealing ring (62) and the movable plate (66) are connected by a connecting plate. The pair of movable plates (66) are connected by a return spring (67). The surface of the rotating column (63) is provided with a sliding groove (69). The end of the movable plate (66) is slidably connected to the sliding groove (69).

6. The energy-saving air preheater according to claim 5, characterized in that, A pair of triangular prisms (68) are fixedly provided on both sides of the notch. When a ring (61) is installed in the notch, the inclined surface on the triangular prism (68) contacts the moving plate (66). When the ring (61) is replaced, the inclined surface will squeeze the moving plate (66), causing the pair of moving plates (66) to move closer to each other, thereby causing the sealing ring (62) to shrink into the annular hole (70).

7. The energy-saving air preheater according to claim 1, characterized in that, The inlet pipe (2) is connected to several main heat exchange tubes (9) through a first distributor (7), and the outlet pipe (3) is connected to several main heat exchange tubes (9) through a second distributor (8). Both the inlet pipe (2) and the outlet pipe (3) pass through the preheating box (1) and are fixedly connected to the preheating box (1).

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