Anti-corrosion device for air pre-heater

Abstract

The utility model provides an anti-corrosion device for an air pre-heater, which comprises a primary air inlet pipe, a secondary air inlet pipe, a primary air outlet pipe and a secondary air outlet pipe, a primary fan is arranged on the primary air inlet pipe, and a secondary fan is arranged on the secondary air inlet pipe; an inlet of the primary fan is communicated with the secondary air outlet pipe through a circulating pipe, and an adjusting mechanism and a gas mixing mechanism are arranged on the circulating pipe; the gas mixing mechanism comprises a gas mixing pipe and a gas inlet pipe, the length direction of the gas mixing pipe is the same as that of the circulating pipe, and the gas mixing pipe is communicated with the circulating pipe; the two gas inlet pipes are evenly arranged in the circumferential direction of the gas mixing pipe, all the gas inlet pipes communicate with the gas mixing pipe, and all the gas inlet pipes are perpendicular to the gas mixing pipe. The anti-corrosion device for the air pre-heater has the advantages of being simple in structure, easy to assemble and use and high in applicability, can be modified based on an existing air pre-heater equipment structure, and is low in modification cost and good in anti-corrosion effect.

Description

Technical Field

[0001] This utility model belongs to the field of air preheater technology, and in particular relates to an anti-corrosion device for air preheaters. Background Technology

[0002] Currently, thermal power units are required to implement environmental protection ultra-clean emission standards. However, due to the difficulty in controlling nitrogen oxide emissions, a large amount of ammonia escapes. The ammonia escape forms ammonium bisulfate, and the urea residue from the denitrification reaction mixes with fly ash, increasing the fly ash viscosity. The flue gas temperature on the primary air side of the air preheater is relatively low, causing the flue gas to reach the acid dew point, resulting in severe ash accumulation and blockage on the air preheater's heating surfaces. Furthermore, the accumulated ash is highly corrosive, easily exacerbating air leakage in the air preheater tube bundle. The root cause is that the temperature of the air preheater's heating surface tube wall is lower than the flue gas acid dew point, causing a series of problems such as ash accumulation on the air preheater's heating surfaces. Moreover, the ash accumulation on the air preheater's heating surfaces cannot be cleaned online during unit operation, posing a safety hazard for long-term unit operation. Therefore, to avoid low-temperature corrosion on the primary air side heating surfaces of the air preheater and alleviate the degree of ash caking in the low-temperature section, the primary air temperature of the air preheater needs to be increased by more than 30°C, so that the cold end temperature of the air preheater is higher than the flue gas dew point temperature. However, the current primary air temperature of the air preheater cannot meet this requirement. Utility Model Content

[0003] In view of this, the present invention aims to propose an anti-corrosion device for air preheaters to solve the problem of low-temperature corrosion on the primary air side heating surface of existing air preheaters.

[0004] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0005] A corrosion protection device for an air preheater includes a primary air inlet pipe, a secondary air inlet pipe, a primary air outlet pipe, and a secondary air outlet pipe. A primary fan is mounted on the primary air inlet pipe, and a secondary fan is mounted on the secondary air inlet pipe. The inlet of the primary fan is connected to the secondary air outlet pipe via a circulation pipe. The circulation pipe is equipped with an adjustment mechanism and a mixing mechanism. The mixing mechanism includes a mixing pipe and an inlet pipe. The length direction of the mixing pipe is the same as the length direction of the circulation pipe, and the mixing pipe is connected to the circulation pipe. Two inlet pipes are evenly arranged along the circumference of the mixing pipe, each inlet pipe being connected to the mixing pipe and perpendicular to the mixing pipe.

[0006] Furthermore, the mixing pipe is detachably mounted on the circulation pipe.

[0007] Furthermore, the mixing pipe includes a large-diameter end and a small-diameter end. The large-diameter end of the mixing pipe is positioned towards the secondary air outlet pipe, and the small-diameter end is positioned towards the primary air fan. The large-diameter end and the small-diameter end of the mixing pipe are connected by a tapered transition section. The air inlet pipe is positioned corresponding to the large-diameter end of the mixing pipe.

[0008] Furthermore, an air guide is provided inside the mixing pipe at the connection between the large-diameter end and the transition section; a ventilation pipe is provided in the middle of the air guide for connecting the large-diameter end and the small-diameter end of the mixing pipe, the ventilation pipe is coaxially arranged with the mixing pipe, and the inner diameter of the ventilation pipe is smaller than the inner diameter of the small-diameter end of the mixing pipe; an air guide groove is provided on one end of the air guide facing the secondary air outlet for connecting the ventilation pipe and the air inlet pipe, and air passage holes are provided on the air guide around the air guide groove for connecting the large-diameter end and the small-diameter end of the mixing pipe, the air passage holes being connected to the air guide groove.

[0009] Furthermore, the air guide groove has a hexagonal structure, and the air intake pipe is set on two opposite sides of the hexagonal structure.

[0010] Furthermore, multiple air vents are evenly distributed.

[0011] Furthermore, the ventilation duct is a tapered structure, with the smaller diameter end of the ventilation duct facing the secondary air outlet duct.

[0012] Furthermore, the adjusting mechanism includes an adjusting gate disposed on the circulation pipe, the adjusting gate being detachably mounted on the circulation pipe.

[0013] Furthermore, the regulating door is a petal-shaped air regulating door.

[0014] Compared with existing technologies, the corrosion protection device for air preheaters described in this utility model has the following advantages:

[0015] This utility model discloses an anti-corrosion device for air preheaters, which has the advantages of simple structure, easy assembly and use, and high applicability. It can be modified based on the existing air preheater equipment structure, with low modification cost and good anti-corrosion effect. By connecting the primary air fan inlet and secondary air outlet pipe with a circulation pipe, it can not only increase the primary air side wall temperature of the air preheater tube bundle, reducing the probability of ash accumulation and blockage on the air preheater tube heating surface, thereby reducing the workload of air preheater cleaning, but also increase the primary hot air temperature at the air preheater outlet. While ensuring boiler efficiency, it alleviates the corrosion rate of the air preheater heating surface, reduces the air preheater leakage rate and fan power consumption, and helps to extend the service life of the air preheater. Attached Figure Description

[0016] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0017] Figure 1 This is a schematic diagram of the structure of an anti-corrosion device for an air preheater according to an embodiment of the present invention;

[0018] Figure 2This is a cross-sectional view of the mixing pipe in an anti-corrosion device for an air preheater according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the air guide component in an anti-corrosion device for an air preheater, as described in an embodiment of this utility model.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. Air preheater; 2. Primary air inlet duct; 3. Secondary air inlet duct; 4. Primary air outlet duct; 5. Secondary air outlet duct; 6. Primary air fan; 7. Secondary air fan; 8. Circulation duct; 9. Adjustment mechanism; 10. Mixing mechanism; 11. Mixing duct; 12. Air inlet duct; 13. Ventilation duct; 14. Air guide; 15. Air passage hole; 16. Air guide groove. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0023] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] A corrosion protection device for air preheaters, such as Figures 1 to 3 As shown, the system includes a primary air inlet duct 2, a secondary air inlet duct 3, a primary air outlet duct 4, and a secondary air outlet duct 5. A primary air fan 6 is installed on the primary air inlet duct 2, and a secondary air fan 7 is installed on the secondary air inlet duct 3. Specifically, the connection methods of the primary air inlet duct 2, secondary air inlet duct 3, primary air outlet duct 4, and secondary air outlet duct 5 to the air preheater 1 are all existing technologies. The primary air fan 6 and secondary air fan 7 can also use existing equipment. The installation and power supply methods of the fans are also existing technologies, and therefore will not be elaborated upon here.

[0027] The main improvement of this utility model is that the inlet of the primary air blower 6 is connected to the secondary air outlet pipe 5 through the circulation pipe 8, and an adjustment mechanism 9 and a mixing mechanism 10 are provided on the circulation pipe 8. Specifically, the mixing mechanism 10 includes a mixing pipe 11 and an inlet pipe 12. The length direction of the mixing pipe 11 is the same as the length direction of the circulation pipe 8. Two inlet pipes 12 are evenly arranged around the circumference of the mixing pipe 11, and each inlet pipe 12 is connected to the mixing pipe 11. Each inlet pipe 12 is perpendicular to the mixing pipe 11.

[0028] For example, the intake pipe 12 is fixed to the mixing pipe 11. By evenly arranging two intake pipes 12 around the circumference of the mixing pipe 11, the cold air entering through the intake pipe 12 can fully collide and mix with the secondary hot air entering through the circulation pipe 8 within the mixing pipe 11, which is beneficial to improving the mixing effect of cold and hot air, thereby increasing the air temperature flowing into the primary air fan 6 through the circulation pipe 8. In actual use, by connecting the inlet of the primary air fan 6 and the secondary air outlet pipe 5 through the circulation pipe 8, the hot air recirculation can be increased, which can not only increase the temperature of the hot air on the primary air side and solve the problem of low temperature of the cold primary air, but also reduce the exhaust gas temperature on the secondary air side, and at the same time reduce the exhaust gas temperature of the mixed flue gas at the outlet of the air preheater 1.

[0029] Preferably, the mixing pipe 11 is detachably mounted on the circulation pipe 8. Exemplarily, the mixing pipe 11 and the circulation pipe 8 can be connected by a flange, and the mixing pipe 11 is connected to the circulation pipe 8. The air inlet pipe 12 can be connected to an external air supply line or directly connected to external air. Those skilled in the art can also choose other methods to install the mixing pipe 11 according to actual needs, to achieve convenient assembly of the mixing pipe 11 and facilitate subsequent replacement and maintenance of the mixing pipe 11; these will not be elaborated further here. In actual use, the circulation pipe 8 can adopt a split structure, with two sections of the circulation pipe 8 connected by a mixing pipe 11. By using a detachable installation method for the mixing pipe 11, the difficulty of using and maintaining this corrosion-resistant device is reduced.

[0030] Preferably, the mixing pipe 11 includes a large-diameter end and a small-diameter end. The large-diameter end of the mixing pipe 11 is disposed towards the secondary air outlet pipe 5, and the small-diameter end is disposed towards the primary air fan 6. The large-diameter end and the small-diameter end of the mixing pipe 11 are connected by a conical transition section. The air inlet pipe 12 is disposed corresponding to the large-diameter end of the mixing pipe 11. By adopting the above-described structure, the hot and cold air entering the mixing pipe 11 through the circulation pipe 8 and the air inlet pipe 12 can be further collided and mixed under the guidance of the conical transition section, thereby improving the uniformity of the hot and cold air mixture and rapidly increasing the temperature of the air entering the small-diameter end.

[0031] Preferably, a guide element 14 is provided inside the mixing pipe 11 at the position corresponding to the connection between the large-diameter end and the transition section; a ventilation pipe 13 is provided in the middle of the guide element 14 for connecting the large-diameter end and the small-diameter end of the mixing pipe 11, the ventilation pipe 13 is coaxially arranged with the mixing pipe 11, and the inner diameter of the ventilation pipe 13 is smaller than the inner diameter of the small-diameter end of the mixing pipe 11; an air guide groove 16 is provided on the end of the guide element 14 facing the secondary air outlet pipe 5 for connecting the ventilation pipe 13 and the air inlet pipe 12, and air passage holes 15 are provided on the guide element 14 around the air guide groove 16 for connecting the large-diameter end and the small-diameter end of the mixing pipe 11, the air passage holes 15 are connected to the air guide groove 16.

[0032] For example, the air guide groove 16 has a hexagonal structure, and the air intake pipe 12 is arranged on two opposite sides of the hexagonal structure. The air guide component 14 is fixed to the mixing pipe 11.

[0033] In practical applications, by setting an air guide 14 inside the mixing pipe 11, the air guide 14 can not only block and disperse the hot air entering through the circulation pipe 8, but also guide the cold air entering through the air inlet pipe, guiding the cold air to flow along the air guide groove 16 to the ventilation pipe, so that the cold air can be fully mixed with the hot air during the flow along the air guide groove 16.

[0034] Meanwhile, by setting the inner diameter of the ventilation duct 13 to be smaller than the inner diameter of the small-diameter end of the mixing pipe 11, the ventilation duct 13 cannot meet all the airflow needs. Some air also needs to pass through the air passage holes 15 around the air guide groove 16 and through the air guide component 14. This not only further increases the distance of cold air flow, ensuring that cold air and hot air are fully mixed and collided, thereby improving the mixing effect of the mixing pipe 11 on cold and hot air and rapidly increasing the temperature of cold air, but also, while ensuring ventilation efficiency, the outer wall of the ventilation duct 13 can be used to disperse and guide the cold air, guiding the cold air to various parts of the air guide groove 16 to mix with the hot air, and finally flowing to the small-diameter end of the mixing pipe 11 through the air passage holes 15.

[0035] Preferably, multiple air passages 15 are evenly arranged. For example, one, two, three or more air passages 15 can be arranged on each side of the air guide groove 16. Those skilled in the art can set them according to actual needs, which will not be elaborated here. By evenly arranging multiple air passages 15, the hot and cold air passing through the air passages 15 can be further dispersed, which is also conducive to improving the mixing effect of hot and cold air.

[0036] Preferably, the ventilation duct 13 is a tapered structure, with its smaller diameter end facing the secondary air outlet duct 5. Exemplarily, the larger diameter end of the ventilation duct 13 is fixed to the air guide 14. Using a tapered structure for the ventilation duct 13 helps reduce its air resistance, and the tapered outer surface of the ventilation duct 13 effectively guides both cold air and hot-cold mixed air, guiding cold air towards the center of the ventilation duct 13 or towards the air passage 15, thereby improving airflow efficiency and reducing air resistance within the mixing duct 11.

[0037] Preferably, the regulating mechanism 9 includes a regulating gate disposed on the circulation pipe 8, the regulating gate being detachably mounted on the circulation pipe 8. Specifically, the regulating gate and the circulation pipe 8 can be connected via a flange. Those skilled in the art can also choose a suitable method to install the regulating gate according to actual needs, so as to achieve detachable installation of the regulating gate, which facilitates subsequent replacement and maintenance of the regulating gate. This will not be elaborated further here.

[0038] For example, the regulating door adopts a petal-shaped air regulating door. By adopting a petal-shaped air regulating door, it is beneficial to improve the uniformity of the flow of secondary hot air after passing through the regulating door, and to ensure the mixing effect of subsequent hot and cold air.

[0039] In practical applications, the anti-corrosion device described in this embodiment, by combining with the existing air preheater 1 equipment structure, adds hot air recirculation on the primary air side of the air preheater 1, and extracts a portion of hot air from the preheater outlet hot secondary air to mix with the cold air at the inlet of the primary air fan 6, thereby increasing the inlet air temperature of the primary air fan 6, and installing regulating valves on the hot air recirculation pipe 8 to facilitate adjustment according to seasonal air temperature and hot air temperature during unit operation.

[0040] This utility model discloses an anti-corrosion device for air preheaters, which has the advantages of simple structure, easy assembly and use, and high applicability. It can be modified based on the existing air preheater equipment structure, with low modification cost and good anti-corrosion effect. By connecting the primary air fan inlet and secondary air outlet pipe with a circulation pipe, it can not only increase the primary air side wall temperature of the air preheater tube bundle, reducing the probability of ash accumulation and blockage on the air preheater tube heating surface, thereby reducing the workload of air preheater cleaning, but also increase the primary hot air temperature at the air preheater outlet. While ensuring boiler efficiency, it alleviates the corrosion rate of the air preheater heating surface, reduces the air preheater leakage rate and fan power consumption, and helps to extend the service life of the air preheater.

[0041] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A corrosion protection device for an air preheater, comprising a primary air inlet pipe (2), a secondary air inlet pipe (3), a primary air outlet pipe (4), and a secondary air outlet pipe (5), wherein a primary air inlet pipe (2) is provided with a primary fan (6), and a secondary air inlet pipe (3) is provided with a secondary fan (7), characterized in that: The inlet of the primary air blower (6) is connected to the secondary air outlet pipe (5) through the circulation pipe (8). The circulation pipe (8) is provided with an adjustment mechanism (9) and a mixing mechanism (10). The mixing mechanism (10) includes a mixing pipe (11) and an inlet pipe (12). The length direction of the mixing pipe (11) is the same as the length direction of the circulation pipe (8), and the mixing pipe (11) is connected to the circulation pipe (8). Two inlet pipes (12) are evenly arranged around the circumference of the mixing pipe (11). Each inlet pipe (12) is connected to the mixing pipe (11), and each inlet pipe (12) is perpendicular to the mixing pipe (11).

2. The anti-corrosion device for an air preheater according to claim 1, characterized in that: The mixing pipe (11) is detachably installed on the circulation pipe (8).

3. A corrosion protection device for an air preheater according to claim 1 or 2, characterized in that: The mixing pipe (11) includes a large-diameter end and a small-diameter end. The large-diameter end of the mixing pipe (11) is set towards the secondary air outlet pipe (5), and the small-diameter end is set towards the primary air fan (6). The large-diameter end and the small-diameter end of the mixing pipe (11) are connected by a tapered transition section. The air inlet pipe (12) is set corresponding to the large-diameter end of the mixing pipe (11).

4. The anti-corrosion device for an air preheater according to claim 3, characterized in that: A guide element (14) is provided inside the mixing pipe (11) at the position corresponding to the connection between the large diameter end and the transition section; a ventilation pipe (13) is provided in the middle of the guide element (14) for connecting the large diameter end and the small diameter end of the mixing pipe (11), the ventilation pipe (13) is coaxially arranged with the mixing pipe (11), and the inner diameter of the ventilation pipe (13) is smaller than the inner diameter of the small diameter end of the mixing pipe (11); a guide groove (16) is provided on one end of the guide element (14) facing the secondary air outlet pipe (5) for connecting the ventilation pipe (13) and the air inlet pipe (12), and an air passage hole (15) is provided on the guide element (14) around the air passage hole (16) for connecting the large diameter end and the small diameter end of the mixing pipe (11), the air passage hole (15) is connected to the air passage hole (16).

5. A corrosion protection device for an air preheater according to claim 4, characterized in that: The air guide groove (16) has a hexagonal structure, and the air intake pipe (12) is set on two opposite sides of the hexagonal structure.

6. A corrosion protection device for an air preheater according to claim 5, characterized in that: Multiple air vents (15) are evenly arranged.

7. A corrosion protection device for an air preheater according to any one of claims 4-6, characterized in that: The ventilation pipe (13) is a tapered structure. The small diameter end of the ventilation pipe (13) is set towards the secondary air outlet pipe (5), and the other end is set on the air guide (14).

8. A corrosion protection device for an air preheater according to claim 1, characterized in that: The regulating mechanism (9) includes a regulating gate provided on the circulation pipe (8), which is detachably installed on the circulation pipe (8).

9. A corrosion protection device for an air preheater according to claim 8, characterized in that: The regulating door is a petal-shaped air regulating door.

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