Boiler tight closed top air draft cooling and waste heat energy-saving recovery system and method

Abstract

The invention relates to the technical field of energy-saving and carbon-reducing transformation of boilers, and discloses an air draft cooling and waste heat energy-saving recovery system and method for a close-fitting closed top of a boiler, and the system comprises an air draft mechanism which is connected with the close-fitting closed top of the boiler and used for extracting high-temperature gas in the close-fitting closed top of the boiler; the gas conveying mechanism comprises a reducer pipe and a main exhaust pipe, the gas conveying mechanism is connected with the exhaust mechanism, and high-temperature gas is conveyed to a fan inlet of the primary fan; the safety protection mechanism is used for coping with risks such as system overpressure, medium backflow and emergency faults, and the safety protection mechanism is arranged on the gas conveying mechanism; and the control mechanism is used for adjusting the air draft amount and starting and stopping of the system, and the dual functions of cooling of the close-fitting closed top of the boiler and recycling of high-temperature gas waste heat are achieved. The closed temperature of the boiler can be effectively reduced, high-temperature gas is recycled, and a large number of heat resources are prevented from being directly wasted.

Description

Technical Field

[0001] This invention relates to the field of boiler energy-saving and carbon-reduction retrofit technology, and more specifically, to a boiler closed-top exhaust cooling and waste heat energy-saving recovery system. Background Technology

[0002] Boiler enclosures are closed structures built around the boiler body, not the internal pressurized system. Their core function is to reduce heat loss, ensure safety, and optimize the operating environment. They are commonly found in medium to large power plant boilers or industrial boilers. In my country, the application of boiler enclosures for coal-fired boilers is characterized by a predominance in the north and a secondary presence in the south, with priority given to densely industrialized areas and full coverage of high-parameter units. Key aspects include: frost protection in cold northern regions and wind and sand protection in arid northwestern regions; necessary measures to improve the thermal efficiency of high-parameter boilers; and requirements for ultra-low emission retrofitting and energy efficiency improvement.

[0003] In actual operation, the main problem with tightly sealed boilers is the high temperature in the furnace top area. This area is affected by both high-temperature radiation and heat conduction from inside the furnace, resulting in significantly higher temperatures in summer. For example, based on field measurements at some power plants in Gansu, the furnace top temperature reaches 55℃-60℃ during summer boiler operation, far exceeding the normal ambient temperature range of 20℃-37℃. This high-temperature environment has multiple negative impacts: it accelerates equipment aging, directly threatening the safe and stable operation of the boiler; it significantly worsens the working environment for operation, inspection, and maintenance personnel, thereby increasing the difficulty and cost of equipment maintenance.

[0004] Currently, conventional cooling methods for boilers with enclosed tops primarily rely on natural heat dissipation and enhanced ventilation. However, these methods are inefficient, especially during the high-temperature periods of summer, failing to achieve the desired cooling standards. High-temperature gases are directly emitted into the atmosphere, resulting in a waste of heat resources. Therefore, there is an urgent need to design a boiler enclosed top exhaust cooling and waste heat recovery system to address these issues. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a boiler closed-top exhaust cooling and waste heat energy-saving recovery system, which can effectively reduce the closed-top temperature of the boiler, recover and reuse high-temperature gas, and avoid a large amount of heat resources being directly wasted.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: The boiler's tightly enclosed top-mounted exhaust cooling and waste heat recovery system includes: The extraction mechanism is tightly connected to the top of the boiler and is used to extract high-temperature gases from its interior. The gas conveying mechanism includes a reducing pipe and a main exhaust pipe. The gas conveying mechanism is connected to the exhaust mechanism and conveys high-temperature gas to the fan inlet of the primary air fan. Safety protection mechanisms are used to address risks such as system overpressure, media backflow, and emergency failures. These safety protection mechanisms are located on the gas delivery mechanism. The control mechanism regulates the air volume and system start / stop, achieving the dual functions of cooling the boiler's tightly sealed top and recovering waste heat from high-temperature gases.

[0007] As a preferred embodiment of the present invention, all components of the extraction unit, gas delivery unit, safety protection unit and control unit are installed in pairs and arranged symmetrically. The symmetrical arrangement includes symmetry along the center line of the tightly sealed top of the boiler.

[0008] As a preferred embodiment of the present invention, the exhaust unit includes several flared exhaust branch pipes, which are arranged above the high-temperature area at the top of the boiler. The pipe openings are equipped with grid-type protective covers, and the pipes are equipped with manually adjustable baffles. The manually adjustable baffles are used to accurately distribute the exhaust volume of each area.

[0009] As a preferred embodiment of the present invention, the gas delivery unit further includes a manifold, which is connected to the outlet end of each flared exhaust branch pipe for collecting the high-temperature gas extracted by each branch pipe; one end of a reducing pipe is connected to the manifold and the other end is connected to the main exhaust pipe, for adapting to the difference in pipe diameter between the manifold and the main exhaust pipe, adjusting the gas fluid pressure and flow rate, and reducing gas impact; the end of the main exhaust pipe away from the reducing pipe is connected to the fan inlet; a filter screen is provided inside the main exhaust pipe for filtering solid impurities such as dust and gravel mixed in with the high-temperature gas; a maintenance manhole is provided at the key maintenance position of the main exhaust pipe for maintenance personnel to enter the pipeline to inspect equipment, clean damper baffles and dust accumulated on the inner wall of the pipeline; supports are provided on the outside of the main exhaust pipe for supporting the weight of the pipeline, limiting pipeline displacement, and reducing pipeline vibration.

[0010] As a preferred embodiment of the present invention, the safety protection unit includes an explosion-proof door, a pneumatic shut-off door, and a check valve. The explosion-proof door is used to release pressure when there is overpressure in the pipeline and is installed at the end of the conveying end of the manifold. The pneumatic shut-off door is installed on the main exhaust pipe and is used to cut off the exhaust passage when the system fails or stops. The check valve is installed at the access point of the main exhaust pipe near the inlet of the primary air fan and is used to prevent primary or secondary air from flowing back into the exhaust system.

[0011] As a preferred embodiment of the present invention, the control unit includes a temperature sensor, an air volume measuring device, a differential pressure flow meter, and an electrically adjustable damper, and adopts a temperature-air volume closed-loop control strategy; the upper ambient temperature of the boiler's tight-fitting enclosure is used as the main control parameter, the upper ambient temperature is the average value of the temperature measured by the temperature sensors of each branch pipe, and the exhaust volume is used as an auxiliary control parameter. The exhaust volume is dynamically changed by adjusting the opening of the electrically adjustable damper, so that the upper ambient temperature of the boiler's tight-fitting enclosure is stabilized within a preset range.

[0012] This invention also provides a method for boiler top-entry ventilation cooling and waste heat recovery, comprising the following steps: S1. System startup preparation: Check whether the status of all equipment in the extraction unit, gas delivery unit, safety protection unit and control unit is normal. S2. Establish a negative pressure exhaust passage, open the manual adjustment baffle door to the preset position, and then open the electric adjustment baffle door to the initial opening to create negative pressure inside the main exhaust pipe, manifold and flared exhaust branch pipe. S3. High-temperature gas extraction and transportation: High-temperature gas is extracted from the tightly sealed top of the boiler through the funnel-shaped exhaust branch pipe. The grid-type protective cover intercepts impurities in the gas. The high-temperature gas enters the manifold through the manually adjustable baffle door, and after the fluid parameters are adjusted by the variable diameter pipe, it is transported by the main exhaust pipe. During the transportation process, the filter screen filters solid impurities in the gas. S4. Waste heat recovery and cooling cycle: The high-temperature gas in the main exhaust duct passes through the electric regulating damper, pneumatic shut-off valve and non-return valve in sequence, and then enters the inlet air duct of the primary air fan or blower. It is fully mixed with the outside cold air in the mixing section. The mixed gas is transported to the air preheater by the fan to participate in the subsequent flue gas process. At the same time, the outside cold air is replenished into the boiler through the tightly sealed doors and windows, forming a cooling cycle of exhausting high temperature and replenishing low temperature. S5. System operation adjustment: The control unit monitors the operating parameters in real time, dynamically adjusts the exhaust volume to maintain the stable ambient temperature of the upper part of the tightly sealed boiler, and responds to abnormal situations. S6. The system stops. Switch the system to manual control and close the electric regulating damper, pneumatic shut-off door, and manual regulating damper in sequence to complete the system shutdown.

[0013] As a preferred embodiment of the present invention, the system operation adjustment in S5 adopts a temperature-airflow closed-loop control strategy. The upper ambient temperature of the boiler's sealed body is the main control parameter, which is the average value of the branch pipe temperature sensor measurement. The exhaust volume is used as an auxiliary control parameter, which is monitored by an airflow measuring device. The control unit adjusts the opening of the electric regulating damper to dynamically change the exhaust volume in the main exhaust pipe, so that the upper ambient temperature of the boiler's sealed body is stabilized within a preset range, with a target of 30°C, which can be adjusted as needed. System operation adjustment = adopts segmented control mode: When the average temperature of the branch pipe temperature sensor is ≤25℃, the control unit automatically shuts down the ventilation system and stops the extraction of high-temperature gas. When 25℃ < average temperature of branch pipe temperature sensor ≤ 45℃, the control unit automatically adjusts the opening of electric regulating damper according to temperature deviation to achieve dynamic adaptation of exhaust volume. When the average temperature of the branch pipe temperature sensor is greater than 45℃, the control unit controls the electric regulating damper to open fully, so that the exhaust system operates at full load.

[0014] As a preferred embodiment of the present invention, S5 employs a safety-priority control logic to handle abnormal situations, specifically including: If the inlet temperature sensor of the fan detects a temperature exceeding 40°C, the control unit automatically reduces the opening of the electric regulating damper to reduce the air volume. If an abnormal negative pressure is detected at the inlet of the primary blower or supply blower, the control unit will automatically reduce the opening of the electric regulating damper until the negative pressure returns to normal. If the temperature sensor of the main exhaust duct detects an abnormal increase in temperature, the control unit will automatically close the pneumatic shut-off door and stop the exhaust system, while simultaneously issuing an audible and visual alarm. If the differential pressure flow meter reports a high differential pressure, the control unit will automatically close the pneumatic shut-off valve and issue an audible and visual alarm. After the maintenance personnel clean the filter, the system will be restarted to resume operation. If the temperature sensor in the mixing section detects a temperature >38℃, the control unit will issue an audible and visual alarm and reduce the opening of the electric adjustment damper door; if the temperature continues to rise to 40℃, the pneumatic shut-off door will be automatically closed to cut off the exhaust passage.

[0015] As a preferred embodiment of the present invention, the waste heat recovery in S4 can be further optimized: a heat pump device is added to the main exhaust pipe to extract the waste heat in the high-temperature gas that is not utilized by the flue gas system for use in factory heating and hot water supply. Alternatively, a variable frequency drive (VFD) can be used to replace the electric regulating damper. Based on the real-time temperature data from the branch pipe temperature sensor, the output frequency of the VFD can be automatically adjusted to change the air volume and improve energy efficiency.

[0016] The beneficial technical effects of this invention are: This invention employs the principle of negative pressure ventilation, using a funnel-shaped exhaust branch pipe as the core extraction component to directionally extract high-temperature gas from the tightly sealed interior of the boiler, significantly improving the high-temperature condition of the upper part of the boiler's sealed interior. As the high-temperature gas is discharged, low-temperature outside gas can be automatically and continuously replenished into the tightly sealed interior of the boiler through the tightly sealed doors and windows, forming a cycle of extraction and replenishment. The extracted high-temperature gas is used to preheat the primary or secondary air, which can increase the temperature of the primary or secondary air and thus reduce fuel consumption.

[0017] Operating the boiler top equipment at around 30℃ slows down the aging rate and extends its service life. The gas temperature in the mixing section can be controlled within a safe range of 30℃-34℃, preventing damage to the equipment from localized high temperatures; at the same time, the temperature inside the tightly sealed boiler body is reduced to 27℃-30℃, improving the safety of the working environment. Attached Figure Description

[0018] Figure 1 This is a side view schematic diagram of the present invention.

[0019] Figure 2 This is a front view schematic diagram of the present invention.

[0020] Figure 3 This is a visual flowchart of the present invention.

[0021] Figure 4 This is a flowchart of the control system of the present invention.

[0022] In the diagram: 1. Trumpet-shaped exhaust branch pipe; 1.1. Grille-type protective cover; 1.2. Manually adjustable baffle door; 2. Manifold; 3. Reducer; 4. Main exhaust pipe; 5. Explosion-proof door; 6. Electric adjustable baffle door; 7. Pneumatic shut-off door; 8. Check valve; 9. Filter screen; 10. Maintenance manhole; 11. Support bracket; 12. Fan inlet; 13. Mixing section; 14. Primary air fan; 15. Boiler tight seal; 16. Denitrification reactor roof; 17. Fan room; a1, a2, a3. Branch pipe temperature sensor; a5. Main exhaust pipe temperature sensor; a6. Fan inlet temperature sensor; a7. Mixing section temperature sensor; b1, b2, b3. Branch pipe airflow measuring device; b4. Main exhaust pipe airflow measuring device; c. Differential pressure flow meter. Detailed Implementation

[0023] In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] Combination Figure 1 - Figure 4 The present invention provides the following embodiments: The boiler's tightly sealed top exhaust cooling and waste heat energy recovery system comprises the following hardware components: 1. Trumpet-shaped exhaust branch pipe, 1.1. Grille-type protective cover, 1.2. Manually adjustable baffle door, 2. manifold, 3. reducer pipe, 4. main exhaust pipe, 5. explosion-proof door, 6. electrically adjustable baffle door, 7. pneumatic shut-off door, 8. non-return door, 9. filter screen, 10. maintenance manhole door, and 11. support brackets.

[0025] The structural layout and core functions of each hardware facility in the system are described below: Trumpet-shaped exhaust branch pipe 1: Located above the high-temperature area at the top of the boiler, it serves as the core inlet component for extracting high-temperature gas under negative pressure. Its trumpet-shaped structure can improve gas extraction efficiency.

[0026] 1.1 Grille-type protective cover: Installed at the inlet of the flared exhaust branch pipe, its core function is to intercept and block debris from entering the pipe during the negative pressure extraction of high-temperature gas, so as to avoid blockage or damage to downstream equipment.

[0027] Manually adjustable damper 1.2: Installed on the flared exhaust branch pipe, the valve opening can be manually adjusted according to the temperature distribution in different areas of the boiler top, thereby achieving precise distribution of exhaust volume in each area.

[0028] Manifold 2: As the converging component of the exhaust branch pipes, its function is to collect and gather the high-temperature gas drawn from each bell-shaped exhaust branch pipe and then smoothly transport it to the main exhaust pipe.

[0029] Reducer 3: Connected between the manifold and the main exhaust pipe, it not only serves as the basic function of pipe connection and specification adaptation, but also adjusts parameters such as fluid pressure and flow rate through gradual change of pipe diameter, while reducing the impact effect during gas flow and improving system stability.

[0030] Main exhaust duct 4: The core delivery channel of the system, responsible for continuously and stably delivering the high-temperature gas collected by the manifold to the inlet duct of the fan, providing a medium guarantee for the subsequent mixing process.

[0031] Explosion-proof door 5: Installed at critical locations in the ventilation duct system, it can be quickly opened to release pressure when an overpressure or explosion occurs inside the duct, effectively protecting the safety of the duct, equipment, and on-site personnel, and preventing the accident from escalating further.

[0032] Electric adjustable damper 6: As the core actuator for system air volume regulation, it can precisely adjust the valve opening through electric drive during system operation to achieve real-time dynamic adjustment of the air volume.

[0033] Pneumatic shut-off door 7: It adopts a pneumatic drive and has a rapid response capability. In the event of an emergency failure in the system or when it needs to be shut down, it can be quickly closed to cut off the ventilation passage and ensure system safety.

[0034] Check valve 8: Installed at the connection point of the main exhaust duct near the fan inlet, it is a one-way flow protection component that can effectively prevent primary or secondary air from flowing back into the exhaust system and avoid equipment failure caused by backflow of the medium.

[0035] Filter 9: Located inside the main exhaust duct, it is used to filter solid impurities such as dust and gravel mixed in with high-temperature gas, reducing the wear of impurities on downstream equipment such as fans and air preheaters.

[0036] Manhole 10: Located at a critical maintenance position in the main exhaust duct, it provides an operating passage for maintenance personnel to enter the duct for maintenance, cleaning dampers and dust accumulation on the inner wall of the duct.

[0037] Pipe support 11: As a supporting and protective component for the pipeline, it mainly bears the weight of the pipeline itself; at the same time, it can limit the displacement range and direction of the pipeline under thermal expansion and contraction, operating vibration or external force, and prevent the pipeline from colliding and being damaged by surrounding equipment; in addition, it can absorb or reduce the vibration generated by the pipeline during operation, and improve the overall stability of the system. Pipe support 11 can be installed on the roof 16 of the denitrification reactor room and the fan room 17 to support the pipeline.

[0038] During the operation of the coal-fired power generating unit, the synchronously matched fan 14 is also in operation. Because the fan inlet is under negative pressure, after the main exhaust pipe 4 of this invention is connected to the air duct of the fan inlet 12, when the manually adjustable damper 1.2, the electrically adjustable damper 6, and the pneumatic shut-off valve 7 are all opened, negative pressure will also be simultaneously formed inside the bell-shaped exhaust branch pipe 1, the manifold 2, the reducer 3, and the main exhaust pipe 4. Under this negative pressure suction, the high-temperature gas inside the boiler's sealed enclosure 15 passes sequentially through the grille-type protective cover 1.1, the bell-shaped exhaust branch pipe 1, the manually adjustable damper 1.2, the manifold 2, and the reducer 3, and then through the electrically adjustable damper 6, the pneumatic shut-off valve 7, the check valve 8, and the filter screen 9 on the main exhaust pipe 4, finally entering the air duct of the fan inlet 12. Figure 1 , Figure 2 As indicated by the red arrow in the middle. Outside cold air enters the air duct from the fan inlet 12, as... Figure 1 , Figure 2 As indicated by the blue arrow, the gas is thoroughly mixed in mixing section 13 with the high-temperature gas extracted from the boiler's tight seal 15, and then conveyed to the air preheater by fan 14. Figure 1 , Figure 2 As indicated by the orange arrow, the process proceeds to the subsequent ventilation and smoke control system.

[0039] The boiler's tightly sealed top exhaust cooling and waste heat energy recovery system includes the following control system: a1, a2, a3 - branch pipe temperature sensors; a5 - main exhaust pipe temperature sensor; a6 - fan inlet temperature sensor; a7 - mixing section temperature sensor; b1, b2, b3 - branch pipe airflow measuring device; b4 - main exhaust pipe airflow measuring device; c - differential pressure flow meter; 1.2 - manual adjustment damper; 6 - electric adjustment damper; 7 - pneumatic shut-off valve; 9 - filter screen.

[0040] The main objectives of the exhaust cooling system control are: to ensure that the ambient temperature in the upper part of the tightly sealed boiler is stable at around 30℃; to ensure the safe and stable operation of the primary or secondary air system; and to achieve automatic system adjustment to reduce manual intervention.

[0041] Based on the above objectives, the following control strategy is adopted: The control strategy prioritizes temperature and uses air volume as a secondary parameter. The upper ambient temperature of the boiler's sealed enclosure is used as the primary control parameter, while the exhaust volume is used as the secondary control parameter, forming a closed-loop control system. Based on the deviation between the set value and the actual value of the upper ambient temperature of the boiler's sealed enclosure, the system automatically adjusts the opening of the electric regulating damper (6) of the exhaust duct to change the exhaust volume, thereby keeping the upper ambient temperature of the boiler's sealed enclosure within the set range.

[0042] Segmented control strategy: Based on changes in ambient temperature and boiler load, the control system is divided into three control segments: Low temperature segment (ambient temperature above the boiler's sealed upper layer ≤ 25℃): The exhaust system automatically shuts off. Medium temperature segment (25℃ < ambient temperature above the boiler's sealed upper layer ≤ 45℃): The exhaust system automatically adjusts according to the ambient temperature above the boiler's sealed upper layer. High temperature segment (ambient temperature above the boiler's sealed upper layer > 45℃): The exhaust system operates at full load.

[0043] Safety Priority Strategy: When the system detects the following abnormal conditions, it will automatically take safety measures: When the temperature of the fan inlet temperature sensor a6 exceeds 40℃, the exhaust volume will be automatically reduced; when the negative pressure at the fan inlet is abnormal, the electric regulating damper 6 will be automatically reduced to decrease the exhaust volume; when the temperature of the main exhaust pipe temperature sensor a5 rises abnormally, the pneumatic shut-off door 7 will be automatically closed and the exhaust system will be shut down.

[0044] The control logic design for the exhaust cooling and waste heat recovery system is as follows: 1. Normal Operation Control Logic: During normal operation, the control logic is as follows: The upper ambient temperature setting for the tightly sealed boiler body is 30℃. This temperature can be adjusted according to actual conditions. The measured ambient temperature of the upper sealed layer of the boiler: the average value of the temperature sensors of branch pipes a1, a2, and a3; Control output: The main exhaust duct is electrically adjustable with a 6-degree opening baffle.

[0045] 2. Abnormal Situation Handling Logic: When the system detects the following abnormal situations, it shall take corresponding handling measures: When the temperature sensor a7 in the mixing section exceeds 38℃: an audible and visual alarm is triggered; the opening of the electric regulating damper 6 of the main exhaust duct is automatically reduced; and the air volume measuring device b4 of the main exhaust duct displays that the exhaust volume decreases accordingly. 3. If the temperature of the mixing section temperature sensor a7 continues to rise to 40℃, the pneumatic shut-off door 7 will automatically close to cut off the exhaust cooling system.

[0046] The boiler's tightly sealed top temperature alarm is triggered when the average temperature of the a1, a2, and a3 branch pipe temperature sensors exceeds 40℃. An audible and visual alarm is issued, and the opening of the electric regulating damper 6 of the main exhaust duct is automatically increased. The air volume measurement device b4 of the main exhaust duct displays the increased exhaust volume accordingly.

[0047] Abnormal negative pressure at the fan inlet: It issues an audible and visual alarm; automatically reduces the opening of the electric regulating damper 6 of the main exhaust duct, and the air volume measuring device b4 of the main exhaust duct displays that the exhaust volume decreases accordingly; it adjusts the exhaust volume of the main exhaust duct according to the recovery of the negative pressure at the fan inlet.

[0048] Differential pressure flow meter C reports a high differential pressure alarm: An audible and visual alarm is triggered; the pneumatic shut-off door 7 automatically closes, cutting off the ventilation and cooling system. After cleaning the filter 9, the ventilation and cooling system is restored.

[0049] The system start-up and shutdown logic is as follows: Start-up sequence: First, check that all equipment in the system is in normal condition; then, open the manual adjustment damper 1.2 to the preset position; next, open the electric adjustment damper 6 of the main exhaust duct to 5%; finally, put the exhaust cooling system into automatic control.

[0050] Stop sequence: 1. Switch the system to manual control; 2. Close the electric regulating damper 6 of the main exhaust duct; 3. Close the pneumatic shut-off valve 7 of the main exhaust duct; 4. Close the manual regulating dampers 1.2 at the outlets of each flared exhaust branch pipe 1; 5. The exhaust cooling system is taken out of operation.

[0051] In this embodiment, a heat pump device can be added to the exhaust system to further extract and utilize the heat from the extracted high-temperature gas. Besides preheating primary or secondary air, this heat can be used for other areas within the plant requiring heating, such as heating systems and hot water supply. This allows for more efficient use of waste heat and improves energy efficiency, but it increases equipment investment and system complexity. Alternatively, a variable frequency drive (VFD) can replace the existing electric damper, automatically adjusting the exhaust volume based on real-time temperature changes within the boiler's sealed enclosure. This makes the exhaust system more energy-efficient, but the VFD is relatively expensive.

[0052] This embodiment consists of 16 types of hardware, including flared exhaust branch pipes, manifolds, reducers, main exhaust pipes, explosion-proof doors, manual / electric adjustable dampers, pneumatic shut-off doors, check valves, filters, and various types of sensors. All components are installed in pairs and arranged symmetrically. Combined with airflow and temperature control logic based on a symmetrical structure, this ensures uniform stress and stable parameters in the system, avoids equipment damage caused by excessive load on one side, extends the system's service life, and guarantees system stability.

[0053] The aforementioned flared exhaust branch pipes are arranged above the high-temperature zone at the top of the boiler, and the flared structure improves the efficiency of high-temperature gas extraction. The reducing pipe connects the manifold and the main exhaust pipe, adapting to different pipe diameters while adjusting fluid parameters and reducing gas impact. Safety protection components include: explosion-proof doors for overpressure relief; check valves to prevent backflow; and pneumatic shut-off doors for emergency shut-off. These safety protection components form a three-tiered safety guarantee. Maintenance components include: manholes providing access to the internal piping, and filters to remove dust and impurities, protecting downstream equipment.

[0054] By utilizing the negative pressure at the fan inlet, a negative pressure environment is created within the system's piping, directionally drawing away the high-temperature gas from the boiler's sealed enclosure. Simultaneously, outside cold air is supplied through the boiler's sealed doors and windows, forming a cycle of high-temperature extraction and low-temperature replenishment, thus stabilizing and controlling the ambient temperature within the boiler's sealed enclosure. The extracted high-temperature gas is not directly discharged but is instead introduced into the fan inlet duct, where it mixes with outside cold air in the mixing section before entering the air preheater. By increasing the initial temperature of the air entering the boiler, fuel consumption is reduced, achieving the dual goals of cooling and energy saving.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A boiler with a tightly sealed top exhaust cooling and waste heat recovery system, characterized in that, include: An extraction mechanism is connected to the top of the boiler body-sealed (15) and is used to extract high-temperature gas from inside the boiler. The gas conveying mechanism includes a reducing pipe (3) and a main exhaust pipe (4). The gas conveying mechanism is connected to the exhaust mechanism to convey high-temperature gas to the fan inlet (12) of the primary fan (14). A safety protection mechanism is provided to address risks such as system overpressure, media backflow, and emergency failures. The safety protection mechanism is located on the gas delivery mechanism. The control mechanism adjusts the ventilation volume and system start / stop to achieve the dual functions of cooling the top of the boiler (15) and recovering and utilizing the waste heat of high-temperature gas.

2. The boiler enclosed top ventilation cooling and waste heat recovery system according to claim 1, characterized in that, All components of the extraction unit, gas delivery unit, safety protection unit and control unit are installed in pairs and arranged symmetrically. The symmetrical arrangement includes symmetry along the top center line of the boiler body enclosure (15).

3. The boiler enclosed top ventilation cooling and waste heat recovery system according to claim 1, characterized in that, The exhaust unit includes several flared exhaust branch pipes (1), which are arranged above the high-temperature area at the top of the boiler. The pipe openings are equipped with grid-type protective covers (1.1), and the pipes are equipped with manually adjustable baffles (1.2). The manually adjustable baffles (1.2) are used to accurately distribute the exhaust volume of each area.

4. The boiler enclosed top ventilation cooling and waste heat recovery system according to claim 1, characterized in that, The gas delivery unit also includes a manifold (2), which is connected to the outlet end of each of the bell-shaped exhaust branches (1) to collect the high-temperature gas extracted by each branch; one end of the reducer (3) is connected to the manifold (2) and the other end is connected to the main exhaust pipe (4) to adapt to the difference in pipe diameter between the manifold (2) and the main exhaust pipe (4), adjust the gas fluid pressure and velocity and reduce gas impact; the end of the main exhaust pipe (4) away from the reducer (3) is connected to the fan inlet (12); a filter screen (9) is provided inside the main exhaust pipe (4) to filter solid impurities such as dust and gravel mixed in the high-temperature gas; a maintenance manhole (10) is provided at the key maintenance position of the main exhaust pipe (4) to allow maintenance personnel to enter the pipeline to maintain equipment, clean the damper baffle and the dust accumulated on the inner wall of the pipeline; a support bracket (11) is provided on the outside of the main exhaust pipe (4) to support the weight of the pipeline, limit the displacement of the pipeline and reduce the vibration of the pipeline.

5. The boiler enclosed top ventilation cooling and waste heat recovery system according to claim 1, characterized in that, The safety protection unit includes an explosion-proof door (5), a pneumatic shut-off door (7), and a check valve (8). The explosion-proof door is used to release pressure when there is overpressure in the pipeline. The explosion-proof door (5) is installed at the end of the conveying of the manifold (2). The pneumatic shut-off door (7) is installed on the main exhaust pipe (4) and is used to cut off the exhaust passage when the system fails or stops. The check valve (8) is installed at the access point of the main exhaust pipe (4) near the inlet of the primary air fan (14) and is used to prevent primary air or secondary air from flowing back into the exhaust system.

6. The boiler enclosed top ventilation cooling and waste heat recovery system according to claim 1, characterized in that... The control unit includes a temperature sensor, an air volume measuring device (b1, b2, b3, b4), a differential pressure flow meter (c), and an electric regulating damper (6). It adopts a temperature-air volume closed-loop control strategy. The upper ambient temperature of the boiler body seal (15) is the main control parameter. The upper ambient temperature is the average value of the measured values ​​of each branch pipe temperature sensor (a1, a2, a3). The exhaust volume is used as an auxiliary control parameter. The exhaust volume is dynamically changed by adjusting the opening of the electric regulating damper (6) so that the upper ambient temperature of the boiler body seal (15) is stabilized within the preset range.

7. A method for boiler top-mounted exhaust cooling and waste heat recovery with a tightly sealed body, characterized in that, Includes the following steps: S1. System startup preparation: Check whether the status of all equipment in the extraction unit, gas delivery unit, safety protection unit and control unit is normal. S2. Establish a negative pressure exhaust passage, open the manual adjustment baffle door (1.2) to the preset position, and then open the electric adjustment baffle door (6) to the initial opening, so that negative pressure is formed inside the main exhaust pipe (4), the manifold (2) and the flared exhaust branch pipe (1); S3. High-temperature gas extraction and transportation: High-temperature gas is extracted from the top of the boiler's tightly sealed (15) through the bell-shaped exhaust branch pipe (1). The grid-type protective cover (1.1) intercepts impurities in the gas. The high-temperature gas enters the manifold (2) through the manually adjustable baffle door (1.2) and is then transported by the main exhaust pipe (4) after the fluid parameters are adjusted by the reducer pipe (3). During the transportation process, the filter screen (9) filters solid impurities in the gas. S4. Waste heat recovery and cooling cycle: The high-temperature gas in the main exhaust pipe (4) passes through the electric regulating baffle door (6), the pneumatic shut-off door (7), and the non-return door (8) in sequence, and then enters the inlet air duct (12) of the primary air fan or blower (14). It is fully mixed with the outside cold air in the mixing section (13). The mixed gas is transported to the air preheater by the fan (14) to participate in the subsequent flue gas process. At the same time, the outside cold air is supplemented into the boiler through the doors and windows of the boiler body seal (15), forming a cooling cycle of exhausting high temperature and supplementing low temperature. S5. System operation adjustment: The operating parameters are monitored in real time by the control unit, and the exhaust volume is dynamically adjusted to maintain the upper ambient temperature of the boiler tightly sealed (15) and to deal with abnormal situations. S6. The system stops. Switch the system to manual control and close the electric regulating baffle door (6), pneumatic shut-off door (7), and manual regulating baffle door (1.2) in sequence to complete the system shutdown.

8. The boiler top-sealed ventilation cooling and waste heat recovery method according to claim 7, characterized in that, In S5, the system operation adjustment adopts a temperature-airflow closed-loop control strategy. The upper ambient temperature of the boiler's tight enclosure (15) is the main control parameter. The upper ambient temperature is the average value measured by the branch pipe temperature sensors (a1, a2, a3). The exhaust volume is the auxiliary control parameter. The exhaust volume is monitored by the airflow measuring device (b1, b2, b3, b4). The control unit adjusts the opening of the electric regulating damper (6) to dynamically change the exhaust volume in the main exhaust pipe (4), so that the upper ambient temperature of the boiler's tight enclosure (15) is stabilized within the preset range, with a target of 30℃. It can be adjusted as needed. The system operation adjustment adopts a segmented control mode: When the average temperature of the branch pipe temperature sensors (a1, a2, a3) is ≤25℃, the control unit automatically shuts down the ventilation system and stops the extraction of high-temperature gas. When the average temperature of the branch pipe temperature sensors (a1, a2, a3) is less than 25℃ and less than 45℃, the control unit automatically adjusts the opening of the electric regulating baffle door (6) according to the temperature deviation to achieve dynamic adaptation of the exhaust volume. When the average temperature of the branch pipe temperature sensors (a1, a2, a3) is greater than 45°C, the control unit controls the electric regulating baffle door (6) to be fully opened, so that the ventilation system operates at full load.

9. The boiler body-sealed top exhaust cooling and waste heat recovery method according to claim 7, characterized in that, The safety-first control logic described in S5 for handling abnormal situations specifically includes: If the inlet temperature sensor (a6) detects a temperature exceeding 40°C, the control unit automatically reduces the opening of the electric regulating damper (6) to reduce the air volume. If an abnormal negative pressure is detected at the inlet of the primary blower or blower (14), the control unit automatically reduces the opening of the electric regulating damper (6) until the negative pressure returns to normal. If the temperature sensor (a5) of the main exhaust pipe detects an abnormal increase in temperature, the control unit will automatically close the pneumatic shut-off door (7) and stop the exhaust system, while issuing an audible and visual alarm. If the differential pressure flow meter (c) reports a high differential pressure, the control unit will automatically close the pneumatic shut-off valve (7) and issue an audible and visual alarm. After the maintenance personnel clean the filter screen (9), the system will be restarted to resume operation. If the temperature sensor (a7) of the mixing section detects a temperature >38°C, the control unit will issue an audible and visual alarm and reduce the opening of the electric regulating baffle door (6); if the temperature continues to rise to 40°C, the pneumatic shut-off door (7) will be automatically closed to cut off the ventilation passage.

10. The boiler top-sealed ventilation cooling and waste heat recovery method according to claim 7, characterized in that, Waste heat recovery in S4 can be further optimized: a heat pump device is added to the main exhaust pipe (4) to extract the waste heat in the high-temperature gas that is not used by the flue gas system for heating and hot water supply in the plant area. Alternatively, a variable frequency drive can be used to replace the electric regulating baffle door (6). Based on the real-time temperature data of the branch pipe temperature sensors (a1, a2, a3), the output frequency of the variable frequency drive can be automatically adjusted to change the air volume and improve energy efficiency.

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