Air preheater ring shock wave cleaning system

Abstract

The utility model discloses a kind of air preheater ring shock wave dust cleaning systems, air preheater rotor cold end end face is divided into two or more concentric rings by partition, including dust cleaning nozzle group, shock wave generator, bleeder line, gas storage tank and gas supply line;Dust cleaning nozzle group, shock wave generator and bleeder line one-to-one, and all are two or more;Each concentric ring below is equipped with dust cleaning nozzle group;Dust cleaning nozzle group includes inflatable pipe, and inflatable pipe is equipped with conical nozzle distributed along length direction, and conical nozzle outlet is towards the concentric ring cold end heat storage element of being;Shock wave generator is arranged on the outside wall of air preheater shell, and bleeder line one end is communicated with the outlet of corresponding shock wave generator, and other end is inserted into air preheater shell and is communicated with corresponding inflatable pipe;Gas supply line one end is communicated with gas storage tank gas outlet, and other end is branched into two gas supply branch lines, and respectively connected the inlet of each shock wave generator.The above-mentioned system effectively solves the problem of incomplete dust blocking of existing rotary air preheater by shock wave.

Description

Technical Field

[0001] This utility model relates to a shock wave cleaning system for air preheaters, belonging to the field of anti-clogging technology for rotary air preheaters. Background Technology

[0002] A rotary air preheater (referred to as a "preheater") is a heat exchange device used in large power plant boilers. It utilizes the heat from boiler flue gas to heat the air needed for combustion, thereby improving boiler efficiency. Key issues concerning preheaters include ash blockage, high air leakage rate, low heat transfer efficiency, and severe low-temperature corrosion. These problems have long affected the safe and economical operation of the equipment. These issues are long-standing and mutually reinforcing. In recent years, with the widespread operation of denitrification systems, the operating environment of preheaters has changed, making the aforementioned ash blockage problem particularly prominent, difficult, and complex to manage.

[0003] Currently, the flue gas denitrification facilities added to coal-fired power plants mainly use selective catalytic reduction (SCR) technology. After adopting the SCR denitrification process, some of the SO2 in the flue gas will be oxidized to SO3 by the denitrification catalyst, increasing the volume concentration of SO3 in the flue gas. In addition, there is an unavoidable ammonia escape phenomenon, which leads to the large-scale generation of by-products such as ammonium bisulfate (NH4HSO4), and also increases the acid dew point temperature of the flue gas, resulting in intensified low-temperature corrosion.

[0004] The aforementioned byproduct, ammonium bisulfate (NH4HSO4), is molten in the temperature range of 146~207 ℃ and adheres firmly to the surface of the heat storage elements in the air preheater, causing corrosion and ash accumulation. This can easily lead to ash blockage, posing a significant threat to the safe operation of the unit. Some power plants in China have already experienced load limitations or even been forced to shut down due to their inability to resolve or mitigate this problem.

[0005] Traditional rotary air preheater cleaning technology involves two steam sootblowers at the hot end and one at the cold end. As the high-pressure superheated steam travels along the sootblower inlet, its pressure gradually decreases. By the time it reaches the front of the sootblower, the pressure is far below the rated sootblower pressure, resulting in only localized cleaning. A large amount of ammonium bisulfate remains on the rotor, causing it to deposit and corrode the heat exchange elements in the air preheater, affecting heat exchange performance and shortening their lifespan. In severe cases, it can affect the thermal balance of the entire boiler combustion system. Furthermore, the deposited ammonium bisulfate increases rotor resistance, leading to increased output power of the induced draft fan at the flue gas outlet and increased energy consumption. Summary of the Invention

[0006] To solve the current problem of ash blockage in air preheaters, this utility model provides an air preheater ring shock wave cleaning system.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: An air preheater ring-shaped shock wave cleaning system is provided, wherein the cold end face of the air preheater rotor is divided into two or more concentric rings by a partition, and includes a cleaning nozzle group, a shock wave generator, an exhaust pipeline, an air storage tank, and an air supply pipeline. The dust removal nozzle assembly is located inside the air preheater shell, while the shock wave generator, air supply pipeline, and air storage tank are all located outside the air preheater shell. The number of cleaning nozzle groups, shock wave generators, and venting pipes are equal, each consisting of two or more, and are in one-to-one correspondence; the number of cleaning nozzle groups is not less than the number of concentric rings, and each concentric ring has at least one cleaning nozzle group below it; the cleaning nozzle group includes an air filling pipe, one end of which is a sealed structure and the other end is an open structure, and the side wall of the air filling pipe is provided with three or more conical nozzles distributed along the length direction, with the outlet of the conical nozzles facing the heat storage element at the cold end of the concentric ring. The shock wave generator is installed on the outer wall of the air preheater shell. One end of the venting pipe is connected to the outlet of the shock wave generator corresponding to the venting pipe, and the other end extends into the air preheater shell and is connected to the open end of the air charging pipe of the cleaning nozzle group corresponding to the venting pipe. That is, the open end of the air charging pipe on the cleaning nozzle, the venting pipe corresponding to this cleaning nozzle, and the outlet of the shock wave generator corresponding to this cleaning nozzle are connected in sequence. One end of the gas supply pipeline is connected to the gas outlet of the gas storage tank, and the other end branches into two gas supply branches. The number of gas supply branches is equal to the number of shock wave generators and they correspond one-to-one. The gas supply branches are connected to the inlet of the corresponding shock wave generator.

[0008] The above-mentioned method reduces costs and saves space by branching the air supply pipeline so that all shock wave generators can share a single air storage tank. By setting the dust removal nozzle group to a multi-cone nozzle structure and arranging the dust removal nozzle group radially in each concentric ring, and using shock waves for purging, a thorough and complete removal of accumulated dust is achieved.

[0009] The above system, through a simple and ingenious arrangement, achieves shock wave cleaning of the split-loop air preheater.

[0010] During operation, once the shock generator outlet is opened, the compressed air stored in the air tank rushes out rapidly, forming a shock wave within the pipeline. This shock wave is then quickly released through the cleaning nozzle assembly, impacting and vibrating the accumulated ash on the cold-end heat storage elements, causing the ash to fall off and be discharged with the airflow. This effectively solves the problem of incomplete cleaning in existing rotary air preheaters.

[0011] During operation, the dust removal nozzle assembly does not rotate with the rotor.

[0012] It is common knowledge that the air preheater rotor contains heat storage elements, so it will not be elaborated here.

[0013] To further improve the dust removal effect, the conical nozzle has a connecting end at one end and an outlet end at the other. The conical nozzle has a structure that gradually tapers from both sides towards the middle in the direction from the connecting end to the outlet end, resulting in a flat, straight outlet. The connecting end of the conical nozzle is connected to the side wall of the air inlet pipe. This design of a flat, straight outlet for the conical nozzle ensures both purging speed and purging range.

[0014] In this application, "connected" means that the two entities are linked and interconnected.

[0015] To further improve the dust removal effect, the distance between the outlet of the conical nozzle and the heat storage element at the cold end of the concentric ring should be ≤0.5m.

[0016] To further ensure the purging speed, the inflation tube has a tapering structure from the open end to the sealed end.

[0017] The sealed end of the aforementioned air-filled pipe points towards the rotor shaft of the air preheater, meaning the air-filled pipe is arranged radially along the rotor, which better ensures the purging range.

[0018] To meet general production needs, the number of conical nozzles on each inflation pipe is 5 to 10, which are evenly spaced.

[0019] To facilitate disassembly and maintenance, the open end of the inflation pipe is connected to the corresponding deflation pipe via a connecting flange. In other words, the open end of the inflation pipe is equipped with a connecting flange, and the end of the deflation pipe connected to the inflation pipe is also equipped with a connecting flange, which facilitates disassembly and maintenance.

[0020] For ease of control, the aforementioned air preheater ring shock wave cleaning system also includes an electrical control unit for sequentially controlling the gas storage in the gas tank and the gas release from the shock wave generator.

[0021] The aforementioned electrical control unit consists of an electrical control cabinet and a solenoid valve, and has automatic sequential control and manual operation modes. In the automatic sequential control mode, the electrical control cabinet receives specific signal commands to control the gas storage tank to store gas and the shock wave generator to release gas. In the manual operation mode, the electrical control cabinet receives local button action signals to control the gas storage tank to store gas and the shock wave generator to release gas. The specific structure and control method adopt existing mature technologies, and this application has not made any special improvements to them, so they will not be described in detail here.

[0022] During operation, the electrical control unit issues a command, and the air tank begins to fill with gas until the preset pressure value is reached, while the shock wave generator remains off. When cleaning is required, the shock wave generator receives a command, and its outlet opens instantly, allowing high-pressure gas to rush out rapidly, forming a shock wave within the pipe. This shock wave propagates at supersonic speed towards the cold-end heat storage element. When the shock wave reaches the ash-covered surface, it generates instantaneous impact force and vibration, causing the ash to fall off and be discharged with the airflow. The shock wave generator's outlet closes, and the air tank begins filling again, awaiting the next soot blowing cycle.

[0023] This application can use a shock generator of model A20003 (brand: Martin Engineering), which has a built-in spring reset mechanism. It can quickly open the outlet, and the opening process takes no more than 1 second.

[0024] The diameter of the aforementioned air supply pipeline shall not be less than DN50, and the diameter of the air release pipeline shall not be less than DN50; both the air supply pipeline and the air release pipeline shall be made of metal. High-pressure rubber hoses may also be used for the air supply pipeline.

[0025] The above-mentioned gas storage tanks shall have a volume of not less than 50L and not more than 1m³, and a pressure resistance rating of not less than 0.5Mpa.

[0026] As one specific preferred embodiment, each of the concentric rings is provided with a set of cleaning nozzles.

[0027] Any technologies not mentioned in this utility model are based on existing technologies.

[0028] This utility model's air preheater ring-type shock wave cleaning system uses shock waves to impact and vibrate the ash accumulated on the concentric ring heat storage elements at the cold end of the air preheater, causing the ash to fall off and be discharged with the airflow. This effectively solves the problem of incomplete ash blockage in existing rotary air preheaters, while avoiding corrosion problems caused by long-term deposition of corrosive substances, extending the service life of heat exchange components, and improving the operational stability of the boiler combustion system. The system has a simple and reasonable structure and is easy to modify and promote. Attached Figure Description

[0029] Figure 1 This is a front view structural diagram of an air preheater ring shock wave cleaning system according to this utility model.

[0030] Figure 2 This is a top view of the shock wave cleaning system for an air preheater according to the present invention.

[0031] Figure 3 This is a front view structural diagram of the cleaning nozzle assembly in the air preheater ring shock wave cleaning system of this utility model.

[0032] Figure 4 This is an axial view of the cleaning nozzle assembly in an air preheater ring shock wave cleaning system according to this utility model.

[0033] Figure 5 for Figure 3 Top view.

[0034] In the diagram, 1 is the dust removal nozzle assembly, 1-1 is the connecting flange, 1-2 is the air charging pipe, 1-3 is the conical nozzle, 2 is the shock wave generator, 3 is the air storage tank, 4 is the air supply pipeline, 5 is the air release pipeline, and 6 is the electrical control unit. Detailed Implementation

[0035] To better understand this utility model, the following embodiments further illustrate the content of this utility model, but the content of this utility model is not limited to the following embodiments.

[0036] The directional terms used in this application, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," refer to the orientation or positional relationship in the usage state. They are used only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application. Example 1

[0037] like Figure 1-2 As shown, an air preheater split-ring shock wave cleaning system is provided. The cold end face of the air preheater rotor is divided into three concentric rings by two baffles. The system includes a cleaning nozzle group, a shock wave generator, an exhaust pipeline, an air storage tank, and an air supply pipeline. The dust removal nozzle assembly is located inside the air preheater shell, while the shock wave generator, air supply pipeline, and air storage tank are all located outside the air preheater shell. The number of cleaning nozzle groups, shock wave generators, and venting pipelines are all three, and they correspond one-to-one. The number of cleaning nozzle groups is not less than the number of concentric rings, and each concentric ring has a cleaning nozzle group below it. The cleaning nozzle group includes an air filling pipe, one end of which is a sealed structure and the other end is an open structure. The side wall of the air filling pipe is provided with three or more conical nozzles distributed along the length direction, and the outlet of the conical nozzles faces the heat storage element at the cold end of the concentric ring. The shock wave generator is installed on the outer wall of the air preheater shell. One end of the venting pipe is connected to the outlet of the shock wave generator corresponding to the venting pipe, and the other end extends into the air preheater shell and is connected to the open end of the air charging pipe of the cleaning nozzle group corresponding to the venting pipe. That is, the open end of the air charging pipe on the cleaning nozzle, the venting pipe corresponding to this cleaning nozzle, and the outlet of the shock wave generator corresponding to this cleaning nozzle are connected in sequence. One end of the gas supply pipeline is connected to the gas outlet of the gas storage tank, and the other end branches into two gas supply branches. The number of gas supply branches is equal to the number of shock wave generators and they correspond one-to-one. The gas supply branches are connected to the inlet of the corresponding shock wave generator.

[0038] The above-mentioned method reduces costs and saves space by branching the air supply pipeline so that all shock wave generators can share a single air storage tank. By setting the dust removal nozzle group to a multi-cone nozzle structure and arranging the dust removal nozzle group radially in each concentric ring, and using shock waves for purging, a thorough and complete removal of accumulated dust is achieved.

[0039] The aforementioned system, through a simple and ingenious arrangement, achieves shock wave cleaning of the split-loop air preheater. During operation, after the shock wave generator outlet is opened, the compressed air stored in the air tank is rapidly released, forming a shock wave within the pipeline. This shock wave is quickly released through the cleaning nozzle assembly, impacting and vibrating the accumulated ash on the cold-end heat storage elements, causing the ash to fall off and be discharged with the airflow. This effectively solves the problem of incomplete cleaning in existing rotary air preheaters. Example 2

[0040] Based on Example 1, the following improvements were made: Figure 3-5 As shown, to further improve the dust removal effect, the conical nozzle has a connecting end at one end and an outlet end at the other. The conical nozzle has a structure that gradually tapers from both sides towards the middle in the direction from the connecting end to the outlet end, and the outlet of the conical nozzle forms a flat, straight line (the length is 8 times the width). The connecting end of the conical nozzle is connected to the side wall of the air inlet pipe. The aforementioned design of the flat, straight outlet of the conical nozzle ensures both the purging speed and the purging range. Example 3

[0041] Based on Example 2, the following improvements were made: Figure 3 As shown, to further ensure the purging speed, the inflation tube has a tapering structure from the open end to the sealed end. Each inflation tube has seven equally spaced conical nozzles. Example 4

[0042] Based on Example 3, the following improvements were made: Figure 2 As shown, the sealed end of the aforementioned air-charging pipe points towards the rotor shaft of the air preheater, meaning the air-charging pipe is arranged radially along the rotor, which better ensures the purging range. To further improve the dust removal effect, the distance between the outlet of the conical nozzle and the heat storage element at the cold end of the concentric ring is 0.5m (or 0.4m, etc.). Example 5

[0043] Based on Example 4, the following improvements were made: Figure 2-3 As shown, for ease of disassembly and maintenance, the open end of the inflation pipe is connected to the corresponding venting pipe via a connecting flange. That is, the open end of the inflation pipe has a connecting flange, and the end of the venting pipe connected to the inflation pipe also has a connecting flange, facilitating disassembly and maintenance. The diameter of both the inflation and venting pipes is not less than DN50; both the inflation and venting pipes are made of metal (316L stainless steel). The gas storage tank has a volume of not less than 50L and not more than 1m³, with a pressure resistance rating of not less than 0.5Mpa. Example 6

[0044] Based on Example 5, the following improvements were further made: Figure 1As shown, for ease of control, the aforementioned air preheater ring shock wave cleaning system also includes an electrical control unit for sequentially controlling the gas storage tank's gas storage and the shock wave generator's gas release. The electrical control unit is mounted on the outer wall of the air preheater housing. The electrical control unit consists of an electrical control cabinet and solenoid valves, and features automatic sequential control and manual operation modes. In automatic sequential control mode, the electrical control cabinet receives specific signal commands to control the gas storage tank's gas storage and the shock wave generator's gas release. In manual operation mode, the electrical control cabinet receives local button operation signals to control the gas storage tank's gas storage and the shock wave generator's gas release. The specific structure and control method utilize existing mature technologies, and this application does not offer any special improvements; therefore, they will not be elaborated further. In this example, the shock wave generator model is A20003, and the brand is Martin Engineering.

[0045] During operation, the electrical control unit issues a command, and the air tank begins to fill with gas until the preset pressure value is reached, while the shock wave generator remains off. When cleaning is required, the shock wave generator receives a command, and its outlet opens instantly, allowing high-pressure gas to rush out rapidly, forming a shock wave within the pipe. This shock wave propagates at supersonic speed towards the cold-end heat storage element. When the shock wave reaches the ash-covered surface, it generates instantaneous impact force and vibration, causing the ash to fall off and be discharged with the airflow. The shock wave generator's outlet closes, and the air tank begins filling again, awaiting the next soot blowing cycle (opening when signs or indications of ash blockage are detected).

[0046] The air preheater ring shock wave cleaning systems described above use shock waves to impact and vibrate the ash accumulation on the concentric ring heat storage elements at the cold end of the air preheater, causing the ash to fall off and be discharged with the airflow. This effectively solves the problem of incomplete ash blockage in existing rotary air preheaters, while avoiding corrosion problems caused by long-term deposition of corrosive substances, extending the service life of heat exchange components, and improving the operational stability of the boiler combustion system. The systems are simple and reasonable in structure and easy to modify and promote.

Claims

1. An air preheater ring-splitting shock wave cleaning system, wherein the cold end face of the air preheater rotor is divided into two or more concentric rings by a partition, characterized in that: It includes a dust removal nozzle assembly, a shock wave generator, a venting pipeline, a gas storage tank, and a gas supply pipeline; The dust removal nozzle assembly is located inside the air preheater shell, while the shock wave generator, air supply pipeline, and air storage tank are all located outside the air preheater shell. The number of cleaning nozzle groups, shock wave generators, and venting pipes are equal, each consisting of two or more, and are in one-to-one correspondence; the number of cleaning nozzle groups is not less than the number of concentric rings, and each concentric ring has at least one cleaning nozzle group below it; the cleaning nozzle group includes an air filling pipe, one end of which is a sealed structure and the other end is an open structure, and the side wall of the air filling pipe is provided with three or more conical nozzles distributed along the length direction, with the outlet of the conical nozzles facing the heat storage element at the cold end of the concentric ring. The shock wave generator is installed on the outer wall of the air preheater shell. One end of the venting pipe is connected to the outlet of the corresponding shock wave generator, and the other end extends into the air preheater shell and is connected to the open end of the air charging pipe of the corresponding dust removal nozzle group. One end of the gas supply pipeline is connected to the gas outlet of the gas storage tank, and the other end branches into two gas supply branches. The number of gas supply branches is equal to the number of shock wave generators and they correspond one-to-one. The gas supply branches are connected to the inlet of the corresponding shock wave generator.

2. The air preheater ring shock wave cleaning system according to claim 1, characterized in that: The conical nozzle has a connecting end at one end and an outlet end at the other end. The conical nozzle has a structure that gradually narrows from both sides to the middle in the direction from the connecting end to the outlet end, and the outlet of the conical nozzle forms a flat, straight line. The connecting end of the conical nozzle is connected to the side wall of the inflation tube.

3. The air preheater ring shock wave cleaning system according to claim 1 or 2, characterized in that: The distance between the cone nozzle outlet and the heat storage element at the cold end of the concentric ring is ≤0.5m.

4. The air preheater ring shock wave cleaning system according to claim 1 or 2, characterized in that: The inflation tube has a tapering structure from the open end to the sealed end.

5. The air preheater ring shock wave cleaning system according to claim 1 or 2, characterized in that: The sealed end of the air inlet pipe points towards the rotor shaft of the air preheater.

6. The air preheater ring shock wave cleaning system according to claim 1 or 2, characterized in that: Each inflation tube has 5 to 10 conical nozzles, which are evenly spaced.

7. The air preheater ring shock wave cleaning system according to claim 1 or 2, characterized in that: The open end of the inflation pipe is connected to the corresponding venting pipe via a connecting flange.

8. The air preheater ring shock wave cleaning system according to claim 1 or 2, characterized in that: It also includes an electrical control unit for sequentially controlling the gas storage in the gas tank and the gas release from the shock generator.

9. The air preheater ring shock wave cleaning system as described in claim 1 or 2, characterized in that: The diameter of the gas supply pipeline shall not be less than DN50, and the diameter of the gas venting pipeline shall not be less than DN50; both the gas supply pipeline and the gas venting pipeline shall be made of metal.

10. The air preheater ring shock wave cleaning system as described in claim 1 or 2, characterized in that: The gas storage tank has a volume of not less than 50L and not more than 1m³, and a pressure resistance rating of not less than 0.5Mpa; each concentric ring is equipped with a set of cleaning nozzles.

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