Air preheater for power station boiler of thermal power plant

Abstract

The invention relates to the technical field of flue gas waste heat recovery, and discloses an air preheater for a power station boiler of a thermal power plant, the air preheater comprises a shell, a supporting seat is fixedly mounted at the bottom of the shell, a rotating shaft is rotatably mounted at the top of the supporting seat, and three partition plates distributed in an annular array are fixedly mounted on the outer side of the top end of the rotating shaft; the top of the shell is divided into a smoke inlet, a primary air outlet and a secondary air outlet through the partition plates, a plurality of heat storage frames distributed in an annular array mode are fixedly installed on the outer side of the rotating shaft, and a set of main heat storage plates and a set of auxiliary heat storage plates are rotationally installed in the heat storage frames. The conversion of the main heat storage plates and the auxiliary heat storage plates in the wave-shaped distribution state and the vertical distribution state can more fully transfer heat from flue gas to the main heat storage plates and the auxiliary heat storage plates, the overall heat exchange performance of the device is optimized, and therefore the efficiency of the whole heat exchange system is improved, and the higher heat exchange effect is achieved.

Description

Technical Field

[0001] This application relates to the technical field of flue gas waste heat recovery, and particularly to an air preheater for utility boilers in thermal power plants. Background Art

[0002] Air preheaters are widely used in the utility boiler systems of thermal power plants. Their purpose is to preheat the air entering the boiler by recovering the heat in the flue gas, thereby improving the thermal efficiency of the boiler, reducing energy consumption, and reducing pollutant emissions. The main principle is to use the residual heat in the flue gas to heat the air entering the boiler, which is usually divided into two airflows: primary air and secondary air.

[0003] In existing regenerative air preheaters, the heat storage plates usually adopt a fixed design. Due to their large surface area and special geometric shape, these corrugated heat storage plates can effectively absorb the heat in the flue gas. When the flue gas flows through the corrugated heat storage plates, the heat is conducted through the heat storage plates to the air, thus realizing heat exchange. However, although the corrugated heat storage plates help to improve the heat exchange efficiency, when the heat storage plates come into contact with the primary air, most of the heat in the heat storage plates is transferred to the primary air through conduction, and the temperature of the primary air rises rapidly. This leads to a significant reduction in the heat transfer efficiency of the heat storage plates when they come into contact with the secondary air. The amount of heat transferred is much lower than that of the primary air, resulting in an insignificant temperature increase of the secondary air, which in turn affects the combustion efficiency and overall thermal efficiency of the boiler. Summary of the Invention

[0004] This application proposes an air preheater for utility boilers in thermal power plants, which has the advantages of optimizing the overall heat exchange performance of the device, thereby improving the efficiency of the entire heat exchange system and achieving a higher heat exchange effect. It is used to solve the problem that the heat exchange efficiency of the internal heat storage plates of existing air preheaters is reduced due to the inability to adjust and change their positions.

[0005] To achieve the above object, this application adopts the following technical solution: An air preheater for utility boilers in thermal power plants includes a housing. A support base is fixedly installed at the bottom of the housing. A rotating shaft is rotatably installed at the top of the support base. Three partition plates are fixedly installed on the outer side of the top end of the rotating shaft and are distributed in a circular array. The partition plates divide the top of the housing into a flue gas inlet, a primary air outlet, and a secondary air outlet, providing a flow space for the flue gas and air.

[0006] A plurality of heat storage frames distributed in an annular array are fixedly installed on the outer side of the rotating shaft. A group of main heat storage plates and a group of secondary heat storage plates are rotatably installed inside the heat storage frames. The plurality of main heat storage plates and secondary heat storage plates are arranged in a staggered manner. Support shafts are fixedly installed on the sides of the main heat storage plates and secondary heat storage plates away from the rotating shaft. One end of the support shaft away from the rotating shaft rotatably penetrates through the protective ring and is fixedly installed with a gear. A plurality of groups of support plates are fixedly installed on the outer side of the protective ring, and each group of support plates is respectively adapted to each group of gears. A rack is slidably installed on the side of each group of support plates close to the gear. The rack is meshed and driven with the gear for adjusting the state of the main heat storage plate or the secondary heat storage plate through meshing transmission.

[0007] Furthermore, a protective ring is fixedly installed on the outer sides of the plurality of heat storage frames together. An installation groove adapted to the protective ring is opened on the inner side wall of the housing. A main adjustment plate is fixedly installed on the inner bottom wall of the installation groove. The main adjustment plate is within the coverage range of the primary air outlet and the secondary air outlet. A secondary adjustment plate is fixedly installed on the inner top wall of the installation groove. The secondary adjustment plate is within the coverage range of the smoke inlet. The relative inner sides of the main adjustment plate and the secondary adjustment plate are both provided with inclined surfaces for controlling the up and down movement of the rack.

[0008] Furthermore, a limit slide bar is fixedly installed on the side of the rack close to the support plate. A limit sliding groove for limit sliding connection with the limit slide bar is opened on the side of the support plate close to the rack, and the limit slide bar is arranged in a T shape.

[0009] Furthermore, one end of the support shaft away from the protective ring penetrates through the gear and is fixedly installed with a fixing plate. Two springs are symmetrically fixedly installed at one end of the fixing plate away from the support shaft. A regulating column is fixedly installed at the ends of the two springs away from the fixing plate together. A plurality of grooves are opened on the inner side wall of the installation groove, and the plurality of grooves are within the coverage range of the secondary air outlet.

[0010] Furthermore, a connecting column is sleeved inside the spring. One end of the connecting column close to the regulating column is fixedly connected with the regulating column. The other end of the connecting column away from the regulating column is slidably connected with the fixing plate.

[0011] Furthermore, a filter screen is fixedly installed on the inner top wall of the protective ring for intercepting dust and impurities.

[0012] The beneficial effects of the present invention are as follows:

[0013] An air preheater for a utility boiler in a thermal power plant provided by the present application, when the heat storage frame, the main heat storage plates and the secondary heat storage plates are rotated by a rotating shaft, the corresponding racks are also rotated accordingly. When the racks move, they move up and down under the extrusion of the main adjusting plate and the secondary adjusting plate. The racks then control the rotation of the main heat storage plates and the secondary heat storage plates through meshing transmission with gears, so that the main heat storage plates and the secondary heat storage plates are transformed between two states of wavy distribution and vertical distribution. The main heat storage plates and the secondary heat storage plates in wavy distribution increase the heat transfer surface area, and also change the path and velocity distribution of gas flow, generating a turbulence effect, which helps to increase the heat transfer efficiency to the flue gas, and can transfer heat from the flue gas to the main heat storage plates and the secondary heat storage plates more fully, thereby improving the heat transfer efficiency of the entire device. After the main heat storage plates and the secondary heat storage plates in vertical distribution exchange heat with the primary air, there is more residual heat on their surfaces. When they exchange heat with the secondary air, the temperature difference between the two is larger, the air resistance is small, the flow rate is faster, and the heat transfer effect on the secondary air is also better. The state distribution of the main heat storage plates and the secondary heat storage plates optimizes the overall heat exchange performance of the device, thereby improving the efficiency of the entire heat exchange system and achieving a higher heat exchange effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings:

[0015] Figure 1 is a three-dimensional structural schematic diagram of the present invention;

[0016] Figure 2 is a front sectional structural schematic diagram of the present invention;

[0017] Figure 3 is a structural schematic diagram of the main heat storage plates and the secondary heat storage plates of the present invention when they are in a wavy distribution;

[0018] Figure 4 is a structural schematic diagram of the main heat storage plates and the secondary heat storage plates of the present invention when they are in a vertical state distribution;

[0019] Figure 5 is a sectional structural schematic diagram of the outer shell and the support seat of the present invention when viewed from the side;

[0020] Figure 6 is of the present invention Figure 2 the enlarged structural schematic diagram at A in;

[0021] Figure 7 is a structural schematic diagram of the support shaft, the fixing plate and the adjusting column of the present invention.

[0022] In the figure: 1. Outer shell; 101. Smoke inlet; 102. Primary air outlet; 103. Secondary air outlet; 2. Support base; 3. Rotating shaft; 4. Partition plate; 5. Heat storage frame; 6. Protective ring; 61. Installation groove; 7. Main heat storage plate; 71. Secondary heat storage plate; 8. Support shaft; 9. Gear; 10. Support plate; 11. Rack; 12. Main adjustment plate; 121. Secondary adjustment plate; 13. Limit slide bar; 14. Fixed plate; 15. Connecting column; 16. Adjustment column; 17. Spring; 18. Groove. Specific embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Embodiment 1, refer to Figures 1 to 7 , an air preheater for a utility boiler in a thermal power plant, including an outer shell 1, a support base 2 is fixedly installed at the bottom of the outer shell 1, a rotating shaft 3 is rotatably installed at the top of the support base 2, and three partition plates 4 distributed in a circular array are fixedly installed on the outer side of the top end of the rotating shaft 3. The partition plates 4 divide the top of the outer shell 1 into a smoke inlet 101, a primary air outlet 102, and a secondary air outlet 103, which are used to provide a flow space for the flue gas and air and separate the flue gas from the air to prevent the two from mixing;

[0025] A plurality of heat storage frames 5 distributed in a circular array are fixedly installed on the outer side of the rotating shaft 3, a protective ring 6 is fixedly installed on the outer sides of the plurality of heat storage frames 5, and a filter screen is fixedly installed on the inner side wall of the top of the protective ring 6 for intercepting dust and impurities. An installation groove 61 adapted to the protective ring 6 is opened on the inner side wall of the outer shell 1. Since the bottom wall and the top wall of the protective ring 6 are respectively attached to the bottom wall or the top wall of the installation groove 61, when the rotating shaft 3 rotates to drive the heat storage frame 5 and the protective ring 6 to rotate, the flue gas or air will not enter the inside of the installation groove 61, achieving the sealing purpose. A group of main heat storage plates 7 and a group of secondary heat storage plates 71 are rotatably installed inside the heat storage frame 5. The plurality of main heat storage plates 7 and secondary heat storage plates 71 are arranged in an alternating manner, and the alternating arrangement between the main heat storage plates 7 and the secondary heat storage plates 71 is in a wavy distribution. The wavy distribution of the main heat storage plates 7 and the secondary heat storage plates 71 can generate a turbulent flow effect. This flow state helps to increase the heat transfer efficiency to the flue gas, so that when the flue gas enters the inside of the outer shell 1 through the smoke inlet 101, the heat can be transferred from the flue gas to the main heat storage plates 7 and the secondary heat storage plates 71 faster, thereby improving the heat exchange efficiency of the entire device.

[0026] On one side of the main heat storage plate 7 and the secondary heat storage plate 71 away from the rotating shaft 3, a support shaft 8 is fixedly installed. One end of the support shaft 8 away from the rotating shaft 3 rotatably penetrates through the protective ring 6 and is fixedly installed with a gear 9. A plurality of support plates 10 are fixedly installed on the outer side of the protective ring 6, and each group of support plates 10 is respectively adapted to each group of gears 9. A rack 11 is slidably installed on the side of each group of support plates 10 close to the gear 9. The rack 11 is in meshing transmission with the gear 9. A main adjusting plate 12 is fixedly installed on the inner bottom wall of the installation groove 61. The main adjusting plate 12 is within the coverage range of the primary air outlet 102 and the secondary air outlet 103. A secondary adjusting plate 121 is fixedly installed on the inner top wall of the installation groove 61. The secondary adjusting plate 121 is within the coverage range of the smoke inlet 101. The relative inner sides of the main adjusting plate 12 and the secondary adjusting plate 121 are both provided with inclined surfaces. When the rack 11 is within the coverage range of the smoke inlet 101, the bottom wall of the rack 11 is in contact with the inner bottom wall of the installation groove 61, and the top wall of the rack 11 is in contact with the bottom wall of the secondary adjusting plate 121. At this time, the corresponding main heat storage plate 7 and secondary heat storage plate 71 are both in an inclined state to form a wavy shape. Due to the wavy main heat storage plate 7 and secondary heat storage plate 71 under the action of the turbulence effect, the heat storage effect is better. Therefore, the main heat storage plate 7 and secondary heat storage plate 71 can better absorb the heat in the flue gas. When the rack 11 enters the coverage range of the primary air outlet 102, the rack 11 moves to one end of the main adjusting plate 12 and moves upward under the action of the main adjusting plate 12 with an inclined surface. When the rack 11 moves, it drives the gear 9 to rotate through the meshing transmission with the gear 9, and then drives the corresponding main heat storage plate 7 or secondary heat storage plate 71 to rotate through the support shaft 8, so that the main heat storage plate 7 and secondary heat storage plate 71 are adjusted to a vertical state. The resistance of the main heat storage plate 7 and secondary heat storage plate 71 in the vertical state to air is small, and more heat remains after the air passes quickly. When the main heat storage plate 7 and secondary heat storage plate 71 after heat exchange with the primary air contact with the secondary air for heat exchange, the temperature difference between the two is larger, and the heat exchange effect on the secondary air is also better. A limiting slide bar 13 is fixedly installed on the side of the rack 11 close to the support plate 10. A limiting chute for limiting sliding connection with the limiting slide bar 13 is opened on the side of the support plate 10 close to the rack 11. The limiting slide bar 13 is T-shaped. The T-shaped limiting slide bar 13 makes it difficult for the rack 11 to shift when sliding up and down, prevents it from falling off the support plate 10, and makes it more stable during operation.

[0027] Embodiment 2, please refer to Figures 5 to 7, on the basis of the first embodiment, one end of the support shaft 8 away from the protection ring 6 penetrates through the gear 9 and is fixedly installed with a fixing plate 14. Symmetrically slidably installed at one end of the fixing plate 14 away from the support shaft 8 are two connecting columns 15. A regulating column 16 is fixedly installed at one end of the two connecting columns 15 away from the fixing plate 14. A spring 17 is sleeved on the outer side of the connecting column 15, and both ends of the spring 17 are fixedly connected to the fixing plate 14 or the regulating column 16 respectively. A plurality of grooves 18 are formed on the inner side wall of the installation groove 61, and the plurality of grooves 18 are within the coverage range of the secondary air outlet 103. When the fixing plate 14 and the regulating column 16 are within the coverage range of the smoke inlet 101 and the primary air outlet 102, the regulating column 16 is squeezed by the inner side wall of the installation groove 61, and the spring 17 is also compressed. After the fixing plate 14 and the regulating column 16 enter the coverage range of the primary air outlet 102, they rotate to a vertical state along with the support shaft 8. Therefore, when the fixing plate 14 and the regulating column 16 enter the coverage range of the secondary air outlet 103, when the regulating column 16 in the vertical state slides to the groove 18, under the action of the elastic force of the spring 17, the regulating column 16 is bounced towards the inner side wall of the groove 18. At the same time, the regulating column 16 also has a certain vibration due to the reaction force. This vibration is then transmitted through the connecting column 15 and the fixing plate 14 to act on the support shaft 8. Finally, the corresponding main heat storage plate 7 or the secondary heat storage plate 71 is vibrated, so that the dust on the surface of the main heat storage plate 7 or the secondary heat storage plate 71 can be detached. The dust detached from the main heat storage plate 7 or the secondary heat storage plate 71 will be blown upward by the air and intercepted by the filter screen. As the protection ring 6 rotates, the filter screen rotates into the coverage range of the smoke inlet 101, and the dust on the filter screen will be blown downward by the flue gas, thereby achieving the effect of dust removal for the main heat storage plate 7 and the secondary heat storage plate 71, and reducing the accumulation speed of the dust on the surfaces of the main heat storage plate 7 and the secondary heat storage plate 71.

[0028] Working principle:

[0029] By using the existing flue gas pipeline, the flue gas is introduced into the interior of the housing 1 from the flue gas inlet 101. Then, by using the existing air pipeline, the primary air and the secondary air are respectively introduced into the interior of the housing 1 from below and flow out through the primary air outlet 102 and the secondary air outlet 103 respectively. The rotating main heat storage plate 7 and the secondary heat storage plate 71 inside the housing 1 absorb the heat in the flue gas and then transfer it to the primary air and the secondary air. When the main heat storage plate 7 and the secondary heat storage plate 71 are placed inside the coverage area of the flue gas inlet 101, the top wall of the corresponding rack 11 is in contact with the bottom wall of the secondary adjusting plate 121, so that the main heat storage plate 7 and the secondary heat storage plate 71 are inclined at this time and form a wavy distribution. The wavy main heat storage plate 7 and secondary heat storage plate 71 increase the heat transfer surface area, change the path and velocity distribution of the gas flow, generate a turbulence effect, which helps to increase the heat transfer efficiency to the flue gas. Furthermore, when the flue gas enters the interior of the housing 1 through the flue gas inlet 101, the heat can be more fully transferred from the flue gas to the main heat storage plate 7 and the secondary heat storage plate 71, thereby improving the heat transfer efficiency of the entire device. At the same time, the corresponding fixing plate 14 and the adjusting column 16 are also in an inclined state;

[0030] When the main heat storage plate 7 and the secondary heat storage plate 71 rotate to the interior of the coverage area of the primary air outlet 102 along with the heat storage frame 5 and the protective ring 6, when the rack 11 contacts the inclined surface of the main adjusting plate 12, under the extrusion of the inclined surface, the rack 11 slides upward. The rack 11 then drives the gear 9 to rotate through meshing transmission, and further drives the support shaft 8 and the corresponding main heat storage plate 7 or secondary heat storage plate 71 to rotate through the gear 9, so that the main heat storage plate 7 and the secondary heat storage plate 71 are adjusted to a vertical state. The main heat storage plate 7 and the secondary heat storage plate 71 in the vertical state have less resistance to air, and more heat remains after the air passes quickly. When the main heat storage plate 7 and the secondary heat storage plate 71 after heat exchange with the primary air come into contact with the secondary air for heat exchange, the temperature difference between the two is larger, and the heat exchange effect on the secondary air is also better. The state distribution of the main heat storage plate 7 and the secondary heat storage plate 71 optimizes the overall heat exchange performance of the device, thereby improving the efficiency of the entire heat exchange system and achieving a higher heat exchange effect;

[0031] As the main heat storage plate 7 and the secondary heat storage plate 71 rotate, the corresponding fixed plate 14 and the adjusting column 16 are also adjusted to the vertical state. When the adjusting column 16 slides to the groove 18, under the action of the elastic force of the spring 17, the adjusting column 16 is bounced towards the inner wall of the groove 18. At the same time, the adjusting column 16 also vibrates to a certain extent due to the reaction force. This vibration is then transmitted through the connecting column 15 and the fixed plate 14 to act on the support shaft 8, ultimately causing the corresponding main heat storage plate 7 or secondary heat storage plate 71 to vibrate, so that the dust on the surface of the main heat storage plate 7 or secondary heat storage plate 71 can be detached. The dust detached from the main heat storage plate 7 or secondary heat storage plate 71 will be blown upward by the air and intercepted by the filter screen. As the protective ring 6 rotates, the filter screen rotates to the inside of the coverage range of the smoke inlet 101, and the dust on the filter screen will be blown downward by the flue gas, thereby achieving the effect of dust removal for the main heat storage plate 7 and the secondary heat storage plate 71, reducing the speed of dust accumulation on the surfaces of the main heat storage plate 7 and the secondary heat storage plate 71. The intermittent vibration of the fixed plate 14 and the adjusting column 16 within the coverage range of the secondary air outlet 103 can not only slow down the speed of dust accumulation on the surfaces of the main heat storage plate 7 and the secondary heat storage plate 71, but also prevent the main heat storage plate 7 and the secondary heat storage plate 71 from being damaged due to long-term vibration, avoiding an increase in maintenance costs.

[0032] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An air preheater for a power plant boiler in a thermal power plant, characterized in that: The invention comprises a shell (1), a support base (2) is fixedly mounted on the bottom of the shell (1), a rotating shaft (3) is rotatably mounted on the top of the support base (2), three partition plates (4) distributed in a ring array are fixedly mounted on the outer side of the top end of the rotating shaft (3), and the partition plates (4) divide the top of the shell (1) into a smoke inlet (101), a primary air outlet (102) and a secondary air outlet (103), so as to provide a flow space for smoke and air; A plurality of heat storage frames (5) distributed in a ring array are fixedly mounted on the outside of the rotating shaft (3); a group of main heat storage plates (7) and a group of secondary heat storage plates (71) are rotatably mounted inside the heat storage frames (5); the plurality of main heat storage plates (7) and secondary heat storage plates (71) are arranged in a staggered manner; a support shaft (8) is fixedly mounted on the side of the main heat storage plates (7) and the secondary heat storage plates (71) away from the rotating shaft (3); and the end of the support shaft (8) away from the rotating shaft (3) is A gear (9) is fixedly mounted on a rotatable protective ring (6). A plurality of groups of support plates (10) are fixedly mounted on the outer side of the protective ring (6). Each group of support plates (10) is matched with each group of gears (9). A rack (11) is slidably mounted on a side of each group of support plates (10) close to the gear (9). The rack (11) is meshed with the gear (9) for transmission and is used to adjust the state of the main heat storage plate (7) or the slave heat storage plate (71) through meshing transmission.

2. The air preheater for a power plant boiler in a thermal power plant according to claim 1, characterized in that: A protective ring (6) is fixedly mounted on the outer sides of the plurality of heat storage frames (5); a mounting groove (61) matched with the protective ring (6) is provided on the inner side wall of the outer shell (1); a main adjustment plate (12) is fixedly mounted on the inner bottom wall of the mounting groove (61); the main adjustment plate (12) is placed within the coverage of the primary air outlet (102) and the secondary air outlet (103); a secondary adjustment plate (121) is fixedly mounted on the inner top wall of the mounting groove (61); the secondary adjustment plate (121) is placed within the coverage of the smoke inlet (101); and the relative inner sides of the main adjustment plate (12) and the secondary adjustment plate (121) are both arranged as inclined surfaces for controlling the up and down movement of the rack (11).

3. The air preheater for a power station boiler in a thermal power plant according to claim 2, characterized in that: A limiting slide bar (13) is fixedly mounted on one side of the rack (11) close to the support plate (10); a limiting slide groove is provided on one side of the support plate (10) close to the rack (11) and is connected to the limiting slide bar (13) in a limiting sliding manner; and the limiting slide bar (13) is arranged in a T-shape.

4. The air preheater for a power plant boiler in a thermal power plant according to claim 2, characterized in that: The end of the support shaft (8) away from the protective ring (6) passes through the gear (9) and is fixedly mounted with a fixing plate (14); the end of the fixing plate (14) away from the support shaft (8) is symmetrically fixedly mounted with two springs (17); the ends of the two springs (17) away from the fixing plate (14) are jointly fixedly mounted with an adjustment column (16); a plurality of grooves (18) are provided on the inner side wall of the mounting groove (61), and the plurality of grooves (18) are placed within the coverage area of ​​the secondary air outlet (103).

5. The air preheater for a power plant boiler in a thermal power plant according to claim 4, characterized in that: A connecting column (15) is sleeved on the inner side of the spring (17); one end of the connecting column (15) close to the adjusting column (16) is fixedly connected to the adjusting column (16); and one end of the connecting column (15) away from the adjusting column (16) is slidably connected to the fixing plate (14).

6. The air preheater for a power plant boiler in a thermal power plant according to claim 1, characterized in that: A filter is fixedly mounted on the inner side wall of the top of the protective ring (6) to intercept dust and impurities.

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