A hot air duct ash discharging device for a coal mill of a power plant boiler

Abstract

The utility model discloses a power plant boiler coal mill hot -blast air duct ash removal device relates to the boiler auxiliary equipment technical field, including with the support pipe of a plurality of coal mill connection and with the support pipe connection's hot -blast mother pipe, and the hot -blast mother pipe tail end is equipped with dust cleaning subassembly, and dust cleaning subassembly includes the discharge pipe of being equipped with in the hot -blast mother pipe tail end, is equipped with the gate valve on the discharge pipe, and dust cleaning subassembly still includes the initiative dust delivery subassembly of being equipped with in the hot -blast mother pipe, and the dust guide mechanism is equipped with in the hot -blast mother pipe, and the dust guide mechanism includes the guide plate of being laid on the hot -blast mother pipe pipe wall. The dust cleaning subassembly of tail end setting is the final export of the dust accumulation, wherein the discharge pipe is used for the dust guided to this concentrated discharge, and the gate valve is used for opening when needing dust cleaning, and is closed to seal the system in normal operation time or dust cleaning after. Initiative dust delivery subassembly provides additional dust cleaning power. Avoided the dust in the mother pipe middle section or elbow place disorderly accumulation, improved dust cleaning efficiency and pertinence significantly, reduced the pipeline jam risk.

Description

Technical Field

[0001] This utility model relates to the technical field of boiler auxiliary equipment. Background Technology

[0002] In coal-fired power plant boiler systems, the pulverizing stage is crucial for ensuring combustion efficiency. After the coal mill grinds the raw coal into fine powder, the pulverized coal needs to be transported to the boiler furnace for combustion using primary air. This system for transporting hot air is called the primary air system. Ambient air is first drawn in and pressurized by a blower, then enters an air preheater, where the waste heat from the boiler's flue gas is used to heat the air to the required temperature. The heated, high-temperature air is collected in a hot air header and then distributed to branch pipes leading to each coal mill. This hot air header is the core hub for the collection and distribution of hot air in the entire primary air system.

[0003] Although coal mill outlets are typically equipped with coarse and fine powder separators to recover most of the substandard coal particles, some extremely fine coal particles and mineral impurities that are difficult to completely separate from the raw coal inevitably escape with the primary airflow. These escaped dust and impurities, under the negative pressure at the blower inlet, enter the blower along with the drawn-in ambient air and are subsequently pressurized and transported. After this hot airflow carrying residual dust is heated by the air preheater, it continues into the hot air header.

[0004] The key reason for severe dust accumulation in hot air headers lies in the changes in internal airflow dynamics and the cumulative effect of long-term operation. Hot air headers are typically designed with large cross-sections to reduce flow velocity, minimize resistance, and distribute airflow evenly. However, when dust-laden airflow enters the large-section header from smaller cross-section pipes such as blower outlet pipes or air preheater connection pipes, the flow velocity decreases significantly. This reduction in velocity greatly weakens the airflow's ability to carry dust particles, making heavier dust particles more likely to settle to the bottom of the header under gravity. Furthermore, the presence of localized eddies, changes in flow direction, or dead zones within the header further exacerbates dust deposition. Long-term continuous operation means this settling process occurs continuously; even small amounts settled each time accumulate over time to form a considerable dust layer at the bottom of the header. Simultaneously, while the hot air temperature is high, it is insufficient to completely prevent settling, and start-ups, shutdowns, or load changes during operation can cause temperature fluctuations, sometimes causing the deposited dust to harden and become even more difficult to remove by airflow. The lack of effective online dust removal methods or insufficient maintenance windows also make it difficult to alleviate the dust accumulation problem in a timely manner. Utility Model Content

[0005] The purpose of this utility model is to provide an ash removal device for the hot air duct of a coal mill in a power plant boiler in order to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, this utility model specifically adopts the following technical solution: A hot air duct ash removal device for a coal mill in a power plant boiler includes branch pipes connected to several coal mills and a hot air main pipe connected to the branch pipes. A ash removal assembly is provided at the end of the hot air main pipe. The ash removal assembly includes a discharge pipe at the end of the hot air main pipe, and a gate valve is provided on the discharge pipe. The ash removal assembly also includes an active ash feeding assembly provided inside the hot air main pipe. A dust guiding mechanism is provided inside the hot air main pipe, and the dust guiding mechanism includes a guide plate laid on the wall of the hot air main pipe. With the above scheme, when hot air carrying pulverized coal flows within the main pipe, some of the heavier particles will settle. The guide plates laid on the pipe wall play a crucial role, altering the natural accumulation pattern of the deposited dust and guiding it along its inclined or specific surfaces towards the end of the hot air main pipe. The end-of-pipe cleaning assembly is the final outlet for the accumulated dust. The discharge pipe is used to centrally discharge the dust guided there, while the gate valve opens when cleaning is needed and closes during normal operation or after cleaning to seal the system. The active dust feeding assembly provides additional cleaning power. By proactively guiding the dust to a designated location in advance through the guide plates, combined with the end-of-pipe discharge pipe and valves, disorderly accumulation of dust in the middle section or bends of the main pipe is avoided, significantly improving the efficiency and targeting of cleaning. This creates favorable conditions for subsequent active cleaning, reducing the risk of pipe blockage and maintenance frequency.

[0007] Furthermore, the active ash feeding assembly includes a ash cleaning pipe distributed along the length of the hot air main pipe. The ash cleaning pipe is connected to the branch pipe through a pipeline. The ash cleaning pipe is laid at the bottom end of the hot air main pipe, and pressurized ash cleaning nozzles are symmetrically distributed on both sides of the ash cleaning pipe. The above scheme arranges the cleaning pipe along the length of the main pipe at its bottom, which is the area with the most severe dust accumulation. Pressurized cleaning nozzles symmetrically distributed on both sides of the cleaning pipe intermittently or continuously spray high-speed airflow downwards and to both sides. This airflow directly acts on the dust layer deposited at the bottom of the main pipe, blowing it up, fluidizing it, and propelling it forward. This achieves active, mechanical removal of dust accumulated at the bottom of the main pipe, particularly solving the problem of caking dust that may not be completely removed by gravity or guide plates alone. The symmetrically distributed nozzles effectively cover the areas on both sides of the cleaning pipe, avoiding cleaning dead zones and significantly enhancing cleaning capacity and reliability.

[0008] Furthermore, the pressurized cleaning nozzles are distributed at an angle and are positioned towards the discharge pipe. With the above method, the nozzles are not installed vertically downwards or arbitrarily, but are intentionally tilted, and their spray direction is uniformly towards the discharge pipe at the end. When the pressurized airflow is ejected from the nozzle, its tilt angle generates a horizontal component force pointing towards the discharge pipe. This component force not only stirs up the dust, but more importantly, continuously drives and transports the stirred-up dust towards the discharge pipe. This greatly optimizes the dust removal efficiency, allowing the airflow energy generated by active dust removal to be effectively utilized for the directional transport of dust, preventing dust from flying disorderly or diffusing backwards within the main pipe.

[0009] Furthermore, the cross-section of the cleaning pipe is arranged in a "C" shape to fit the hot air main pipe, and the air outlet of the pressurized cleaning nozzle is either rectangular or fan-shaped. Through the above scheme, the "C"-shaped cross-section cleaning pipe can closely fit the inner wall of the curved bottom of the hot air main pipe, minimizing its own space occupation while maximizing the fit between its lower and side surfaces and the bottom of the main pipe, providing a good foundation for nozzle installation. The rectangular or fan-shaped nozzle outlet design, compared to a circular nozzle, can generate a flat or fan-shaped airflow field with a wider coverage area. This improves the coverage and uniformity of the airflow on the deposition surface at the bottom of the main pipe, enhancing the effectiveness and efficiency of a single cleaning operation.

[0010] Furthermore, the guide plate is inclined toward the discharge pipe, the cleaning pipe is laid on the guide plate, the guide plate is arc-shaped and fits into the hot air main pipe, and the guide plate and the cleaning pipe are fixed by riveting. With the above design, the guide plate is inclined towards the discharge pipe, and its overall shape is an arc that fits snugly against the inner wall of the hot air main pipe. Dust, under the influence of gravity, naturally slides down or is disturbed by airflow, and is continuously guided towards the discharge pipe by the inclined guide plate surface. The cleaning pipe is no longer directly mounted on the bottom of the main pipe, but is laid directly on the guide plate, and the two are firmly fixed by riveting. In this way, the guide plate serves the dual function of guiding dust and acting as a mounting base for the cleaning pipe.

[0011] Furthermore, the hot air header is provided with an observation window. The above solution involves installing pressure-resistant and high-temperature-resistant observation windows at appropriate locations on the hot air header. Operation or maintenance personnel can then visually observe the ash accumulation inside the header, the operational status of the cleaning components, and the cleaning effect through these windows.

[0012] Furthermore, a pressurizing fan is installed on the ash removal pipe, and the pressurizing fan is driven by a variable frequency PLC controller. With the above scheme, the pressurized blower provides power as the air source for the ash cleaning pipe, and its operation is precisely controlled by a variable frequency PLC controller. The PLC can dynamically adjust the speed of the blower according to the preset program, operating conditions, or feedback signals from the observation window / other sensors, thereby steplessly adjusting the pressure and flow rate of the compressed air output to the ash cleaning pipe.

[0013] The beneficial effects of this utility model are as follows: 1. This utility model has a simple structure. When hot air carrying coal powder particles flows in the main pipe, some of the heavier particles will settle. The guide plate laid on the pipe wall plays a key role, changing the natural accumulation pattern of the deposited dust and guiding the dust to move towards the end of the hot air main pipe along its inclined or specific surface. The dust removal component at the end is the final outlet for the accumulated dust. The discharge pipe is used to centrally discharge the dust guided there, and the gate valve is used to open when dust removal is needed and close during normal operation or after dust removal to seal the system. The active dust feeding component provides additional dust removal power. By actively guiding the dust to the designated location in advance by the guide plate, combined with the discharge pipe and valve at the end, the disorderly accumulation of dust in the middle section or bend of the main pipe is avoided, which significantly improves the efficiency and targeting of dust removal, creates favorable conditions for subsequent active dust removal, and reduces the risk of pipeline blockage and maintenance frequency. 2. The PLC can dynamically adjust the fan speed according to the preset program, operating conditions, or feedback signals from the observation window / other sensors, thereby steplessly adjusting the pressure and flow rate of the compressed air output to the dust removal pipe. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Attached reference numerals: 11. Branch pipe; 12. Hot air main pipe; 13. Discharge pipe; 14. Gate valve; 15. Baffle plate; 16. Ash removal pipe; 17. Pressurized ash removal nozzle; 18. Observation window; 19. Pressurized fan. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0018] Example 1 like Figure 1 As shown, this embodiment provides an ash removal device for the hot air duct of a coal mill in a power plant boiler, including branch pipes 11 connected to several coal mills and a hot air main pipe 12 connected to the branch pipes 11. A ash removal assembly is provided at the end of the hot air main pipe 12. The ash removal assembly includes a discharge pipe 13 located at the end of the hot air main pipe 12, and a gate valve 14 is provided on the discharge pipe 13. The ash removal assembly also includes an active ash feeding assembly located inside the hot air main pipe 12. A dust guiding mechanism is provided inside the hot air main pipe 12. The dust guiding mechanism includes a guide plate 15 laid on the wall of the hot air main pipe 12. The active ash feeding assembly includes ash removal pipes 16 distributed along the length of the hot air main pipe 12. The ash removal pipes 16 are connected to the branch pipes 11 through pipes. The ash removal pipes 16 are laid at the bottom end of the hot air main pipe 12. Pressurized ash removal nozzles 17 are symmetrically distributed on both sides of the ash removal pipes 16.

[0019] As hot air carrying pulverized coal flows within the main pipe, some of the heavier particles settle. The guide vanes 15, laid on the pipe wall, play a crucial role, altering the natural accumulation pattern of the deposited dust and guiding it along its inclined or specific surfaces towards the end of the hot air main pipe 12. The cleaning pipe 16 is arranged along the length of the main pipe at its bottom, in the area with the most severe dust accumulation. Pressurized cleaning nozzles 17, symmetrically distributed on both sides of the cleaning pipe 16, intermittently or continuously spray high-speed airflow downwards and to both sides. This airflow directly acts on the dust layer deposited at the bottom of the main pipe, blowing it up, fluidizing it, and propelling it forward. This achieves active, mechanical removal of dust accumulated at the bottom of the main pipe, particularly solving the problem of caking dust that may not be completely removed by gravity or the guide vanes 15 alone. The cleaning assembly at the end is the final outlet for the accumulated dust. The discharge pipe 13 is used to centrally discharge the dust guided there, while the gate valve 14 is used to open when cleaning is needed and close during normal operation or after cleaning to seal the system. The active dust feeding component provides additional cleaning power. By pre-directing the dust flow to a designated location through the guide plate 15, combined with the discharge pipe 13 and valve at the end, it avoids the disorderly accumulation of dust in the middle section or bend of the main pipe, which significantly improves the efficiency and targeting of dust cleaning, creates favorable conditions for subsequent active dust cleaning, and reduces the risk of pipeline blockage and maintenance frequency.

[0020] Reference Figure 1The pressurized dust removal nozzles 17 are inclined and face the discharge pipe 13. The cross-section of the dust removal pipe 16 is C-shaped, fitting the hot air header 12. The air outlets of the pressurized dust removal nozzles 17 are either rectangular or fan-shaped. A pressurized fan 19 is installed on the dust removal pipe 16, driven by a variable frequency PLC controller. The pressurized fan 19 provides power to the dust removal pipe 16, and its operation is precisely controlled by the variable frequency PLC controller. The nozzles are not installed vertically downwards or arbitrarily, but are intentionally inclined, and their spray direction is uniformly towards the discharge pipe 13 at the end. When the pressurized airflow is ejected from the nozzle, its inclination angle generates a horizontal component force pointing towards the discharge pipe 13. This component force not only raises the dust, but more importantly, continuously drives and transports the raised dust towards the discharge pipe 13. This significantly optimizes dust removal efficiency, effectively utilizing the airflow energy generated by active dust removal for directional dust transport. The PLC can dynamically adjust the fan speed based on preset programs, operating conditions, or feedback signals from the observation window 18 / other sensors, thereby steplessly adjusting the pressure and flow rate of the compressed air output to the dust removal pipe 16. The "C"-shaped cross-section of the dust removal pipe 16 tightly fits the arc-shaped bottom inner wall of the hot air header 12, minimizing its own space occupation while maximizing the fit between its lower and side surfaces and the bottom of the header, providing a good foundation for nozzle installation. The rectangular or fan-shaped nozzle outlet design, compared to a circular nozzle, can generate a flat or fan-shaped airflow field with a wider coverage area. This improves the coverage and uniformity of the airflow on the deposition surface at the bottom of the header, enhancing the effect and efficiency of a single dust removal action.

[0021] Reference Figure 1 The hot air header 12 is equipped with an observation window 18, which is pressure-resistant and high-temperature resistant and installed at an appropriate position on the hot air header 12. Operation or maintenance personnel can directly observe the dust accumulation inside the header, the working status of the dust removal components, and the dust removal effect through this window.

[0022] Reference Figure 1 The guide plate 15 is inclined towards the discharge pipe 13, and the cleaning pipe 16 is laid on the guide plate 15. The guide plate 15 is generally arc-shaped and fits into the hot air header 12. The guide plate 15 and the cleaning pipe 16 are fixed together by riveting. The guide plate 15 itself is designed to be inclined towards the discharge pipe 13, and its overall shape is arc-shaped and fits into the inner wall of the hot air header 12. Dust will naturally slide down under gravity or be disturbed by airflow and will be continuously guided towards the discharge pipe 13 by the inclined guide plate 15.

[0023] Implementation Principle: This utility model has a simple structure. When hot air carrying coal powder particles flows inside the main pipe, some of the heavier particles will settle. The guide plate 15 laid on the pipe wall plays a key role, changing the natural accumulation pattern of the deposited dust and guiding the dust along its inclined or specific surface towards the end of the hot air main pipe 12. The dust removal component at the end is the final outlet for the accumulated dust. The discharge pipe 13 is used to centrally discharge the dust guided there, and the gate valve 14 is used to open when dust removal is needed and close during normal operation or after dust removal to seal the system. The active dust feeding component provides additional dust removal power. By actively guiding the dust to the designated location in advance through the guide plate 15, combined with the discharge pipe 13 and valve at the end, disorderly accumulation of dust in the middle section or bend of the main pipe is avoided, significantly improving the efficiency and targeting of dust removal, creating favorable conditions for subsequent active dust removal, and reducing the risk of pipeline blockage and maintenance frequency.

[0024] It should be noted that the connection relationships of components not specifically mentioned in this application are all assumed to be based on existing technology. Since they do not involve the inventive point and are commonly used in existing technology, the structural connection relationships are not described in detail.

Claims

1. A hot air duct ash removal device for a coal mill in a power plant boiler, comprising branch pipes (11) connected to several coal mills and a hot air main pipe (12) connected to the branch pipes (11), characterized in that, A dust removal assembly is provided at the end of the hot air main pipe (12). The dust removal assembly includes a discharge pipe (13) at the end of the hot air main pipe (12). A gate valve (14) is provided on the discharge pipe (13). The dust removal assembly also includes an active dust feeding assembly provided in the hot air main pipe (12). A dust guiding mechanism is provided in the hot air main pipe (12). The dust guiding mechanism includes a guide plate (15) laid on the pipe wall of the hot air main pipe (12).

2. The ash removal device for the hot air duct of a coal mill in a power plant boiler according to claim 1, characterized in that, The active ash feeding assembly includes a ash cleaning pipe (16) distributed along the length of the hot air main pipe (12). The ash cleaning pipe (16) is connected to the branch pipe (11) through a pipe. The ash cleaning pipe (16) is laid at the bottom end of the hot air main pipe (12). Pressurized ash cleaning nozzles (17) are symmetrically distributed on both sides of the ash cleaning pipe (16).

3. The ash removal device for the hot air duct of a coal mill in a power plant boiler according to claim 2, characterized in that, The pressurized cleaning nozzles (17) are distributed at an angle and are positioned toward the discharge pipe (13).

4. The ash removal device for the hot air duct of a coal mill in a power plant boiler according to claim 3, characterized in that, The cross-section of the cleaning pipe (16) is arranged in a "C" shape that fits the hot air main pipe (12), and the air outlet of the pressurized cleaning nozzle (17) is either rectangular or fan-shaped.

5. The ash removal device for the hot air duct of a coal mill in a power plant boiler according to claim 3, characterized in that, The guide plate (15) is inclined toward the discharge pipe (13), and the cleaning pipe (16) is laid on the guide plate (15). The guide plate (15) is arc-shaped and fits the hot air main pipe (12). The guide plate (15) and the cleaning pipe (16) are fixed by riveting.

6. The ash removal device for the hot air duct of a coal mill in a power plant boiler according to claim 1, characterized in that, The hot air header (12) is provided with an observation window (18).

7. The ash removal device for the hot air duct of a coal mill in a power plant boiler according to claim 3, characterized in that, The cleaning pipe (16) is equipped with a pressurizing fan (19), which is driven by a variable frequency PLC controller.

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