On-line regulation and control system and method for regulating flue gas waste heat recovery amount of wide-channel plate-type low-temperature economizer

Abstract

The invention relates to the technical field of flue gas waste heat recovery, and discloses an online regulation and control system and method for regulating the flue gas waste heat recovery amount of a wide-channel plate type low-temperature economizer. The system comprises a flue gas treatment main process assembly, a low-temperature economizer water circulation assembly and an intelligent regulation and control assembly. Sensors are arranged at all key parts, an intelligent control unit is used for regulating and controlling a circulating water pump, a valve and other assemblies on the basis of a control model and real-time data, and the flue gas waste heat recovery amount is precisely regulated and controlled. Meanwhile, the system has the functions of data storage and analysis, fault diagnosis and interaction with external meteorological equipment, can optimize a control strategy, guarantees the system stability, and improves the adaptability. According to the system and method, the energy utilization efficiency is effectively improved, it is ensured that the system stably operates under complex working conditions, and the system and method have wide application prospects in the fields of thermal power generation and the like.

Description

Technical Field

[0001] The invention relates to the field of wide channel plate type low temperature economizer regulating flue gas waste heat recovery amount, and in particular to an online control system and method for wide channel plate type low temperature economizer regulating flue gas waste heat recovery amount. Background Art

[0002] In areas such as thermal power generation, a large amount of waste heat is contained in boiler flue gas. Traditional flue gas waste heat recovery systems have many problems, such as the difficulty in accurately regulating the amount of waste heat recovery according to actual operating conditions, which limits energy utilization efficiency. At the same time, the lack of effective data management and analysis during system operation is not conducive to troubleshooting and optimization control. In addition, the equipment is susceptible to the accumulation of dirt that affects the heat exchange efficiency, and lacks flexibility in responding to changes in operating conditions, making it impossible to ensure the stable operation of the entire thermal system. Summary of the invention

[0003] The object of the present invention is to provide an online control system and method for adjusting the amount of flue gas waste heat recovery in a wide-channel plate-type low-temperature economizer.

[0004] The present invention is achieved through the following technical solutions.

[0005] Wide channel plate type low temperature economizer regulates flue gas waste heat recovery amount online control system, including: Main process components of flue gas treatment: including air preheater, low-temperature economizer, electrostatic precipitator, induced draft fan, absorption tower, wet electrostatic precipitator and chimney, the inlet of low-temperature economizer is connected with the outlet of air preheater, the flue gas outlet of low-temperature economizer is connected with the flue gas inlet of electrostatic precipitator, the flue gas of electrostatic precipitator is transported to the flue gas inlet of absorption tower through induced draft fan, the flue gas outlet of absorption tower is connected with the flue gas inlet of wet electrostatic precipitator, the flue gas outlet of wet electrostatic precipitator is connected with the flue gas inlet of chimney, a pressure sensor is installed on the inlet pipe of low-temperature economizer to monitor the flue gas pressure entering the low-temperature economizer, and a temperature sensor is installed on the flue gas outlet pipe of low-temperature economizer to detect the flue gas temperature discharged from low-temperature economizer; Low-temperature economizer water circulation components: The water outlet and water inlet of the low-temperature economizer are respectively provided with a low-temperature economizer outlet valve and a low-temperature economizer inlet valve, the outlet of the low-temperature economizer outlet valve and the inlet of the low-temperature economizer inlet valve are connected with a bypass pipe, a circulating water pump and a low-temperature economizer bypass valve are provided on the bypass pipe, a pressurized water pump is installed on the inlet pipe of the low-temperature economizer inlet valve, three groups of low-temperature heating pipe circulating water inlets are provided with low-temperature heating inlet valves, the low-temperature heating inlet valves are connected to the low-temperature heating inlet valves through pipes with low-temperature heating inlet valves and low-temperature heating bypass valves, the low-temperature heating inlet valves are connected to the low-temperature heating inlet valves through branch pipes with two groups of low-temperature heating pipes and low-temperature heating outlet valves, the pipes connected with the low-temperature heating inlet valves and the low-temperature heating split valves are connected with a water supply pipeline with a low-temperature heating pipe, the outlet pipe branch of the low-temperature economizer can flow directly into the heater, and the outlet pipe of the heater merges into the low-temperature heating inlet valve, and a temperature sensor and a temperature sensor are respectively installed at the water inlet and outlet of each group of low-temperature heating pipes to monitor the temperature change of the circulating water in the low-temperature heating pipes; Intelligent control component: including an intelligent control unit, which is electrically connected to the pressure sensor, temperature sensor, circulating water pump, low-temperature economizer bypass valve, booster water pump, each low-temperature economizer inlet valve, low-temperature economizer bypass valve, low-temperature economizer outlet valve and each temperature sensor and temperature sensor. The intelligent control unit has a built-in control model based on the relationship between the flue gas waste heat recovery amount and the operating parameters of each component under different working conditions. It can calculate the optimal operating parameter adjustment strategy through the control model according to the data feedback from the pressure sensor, temperature sensor and each low-temperature economizer pipe-related temperature sensor, and then control the operating status of the circulating water pump, low-temperature economizer bypass valve, booster water pump, each low-temperature economizer inlet valve, low-temperature economizer bypass valve, and low-temperature economizer outlet valve components to achieve online precise control of the flue gas waste heat recovery amount of the low-temperature economizer. At the same time, the intelligent control unit also has data storage and analysis functions, and can regularly store and analyze the system operation data to optimize the control model and troubleshoot system faults.

[0006] Furthermore, the intelligent control unit is connected to a data storage module, which uses a large-capacity hard disk and can store at least one year's system operation data, including but not limited to historical monitoring data of each sensor, switch and operation parameter records of each valve and water pump, and flue gas waste heat recovery data at different times; at the same time, the data storage module has a data encryption function to ensure the security and confidentiality of the data and prevent data leakage; by analyzing the stored historical data, the changing trend of the system operation status can be traced, providing strong data support for optimizing control strategies, predicting equipment maintenance cycles and troubleshooting, and further improving the reliability and stability of the system.

[0007] Furthermore, flow regulating baffles are respectively provided on the flue gas inlet and outlet pipes of the low-temperature economizer. The flow regulating baffles are made of special high-temperature resistant and corrosion-resistant alloy materials to ensure long-term stable operation in a high-temperature flue gas environment; its electric actuator has a high-precision position feedback system, which can accurately feedback the actual opening of the baffle to the intelligent control unit; the intelligent control unit is based on advanced algorithms, and according to the real-time operation requirements of the system, such as changes in boiler load, fluctuations in fuel quality, and changes in external ambient temperature factors, it quickly and accurately controls the opening of the flow regulating baffle, thereby realizing stepless regulation of the flue gas flow entering and discharging the low-temperature economizer; this dynamic adjustment method can enable the low-temperature economizer to always maintain the best heat exchange efficiency under various operating conditions, effectively improve the system's recovery and utilization rate of flue gas waste heat, and at the same time help to stabilize the operating parameters of the entire thermal system and reduce the adverse effects of operating condition fluctuations on the equipment.

[0008] Furthermore, the circulating water pump is a variable frequency speed regulating water pump, and its speed can be continuously adjusted within the range of 0-5000 rpm; the intelligent control unit accurately controls the speed of the circulating water pump according to the real-time operating parameters of the system and the target value of the flue gas waste heat recovery; when the flue gas waste heat recovery amount is low, the circulating water pump speed is reduced to reduce energy consumption; when the flue gas waste heat recovery amount needs to be increased, the circulating water pump speed is increased to increase the circulating water flow rate, so that the heat exchange in the low-temperature economizer is more sufficient; this variable frequency speed regulation control method can dynamically adjust the circulating water flow rate according to actual needs, improve the energy utilization efficiency of the system, and at the same time reduce the mechanical wear of the water pump and extend the service life of the circulating water pump.

[0009] Furthermore, the low-temperature economizer bypass valve adopts an electric butterfly valve, which has good sealing performance and a leakage rate of less than 0.1%; the electric butterfly valve has a fast switching speed and can complete the full opening or full closing action within 1-5 seconds, and can accurately control the valve opening, and the opening adjustment accuracy can reach ±1%; the intelligent control unit controls the opening of the low-temperature economizer bypass valve according to the system operation status. When it is necessary to increase the flue gas treatment capacity of the low-temperature economizer, the low-temperature economizer bypass valve is closed to allow more flue gas to pass through the low-temperature economizer; when the low-temperature economizer needs maintenance or fails, the low-temperature economizer bypass valve is quickly opened to ensure that the system flue gas passage is unobstructed, does not affect the normal operation of the entire system, and improves the reliability and flexibility of the system.

[0010] Furthermore, an automatic cleaning device is arranged inside the low-temperature economizer, and the automatic cleaning device comprises a plurality of high-pressure nozzles, which are evenly distributed between the plates of the low-temperature economizer, and the spraying direction of the nozzles is toward the surface of the plate; when the intelligent control unit detects that the accumulation of plate dirt reaches a certain level according to a preset cleaning cycle or according to the plate pressure difference sensor, the automatic cleaning device is started; the high-pressure nozzle sprays a high-pressure water flow to clean the plate, removes the dirt and impurities on the surface of the plate, and ensures the heat exchange efficiency of the plate; at the same time, the sewage generated during the cleaning process is discharged through a special drainage pipe to avoid pollution to other parts of the system, thereby ensuring the long-term stable and efficient operation of the low-temperature economizer.

[0011] The method for online regulating the amount of flue gas waste heat recovery by a wide channel plate type low temperature economizer comprises the following steps: System preparation and parameter setting steps: Start the wide-channel plate-type low-temperature economizer to adjust the flue gas waste heat recovery amount online control system, set the target value range of the flue gas waste heat recovery amount under different working conditions in the intelligent control unit. These target value ranges are determined based on multiple factors such as power generation efficiency requirements, environmental emission standards, and equipment operation safety. At the same time, the operating parameter thresholds related to each component and the control model of the relationship between the flue gas waste heat recovery amount and the operating parameters of each component based on a large amount of experimental and actual operation data are input into the intelligent control unit, and each sensor is calibrated to ensure measurement accuracy; Real-time data collection steps: The flue gas pressure data entering the low-temperature economizer is collected in real time by a pressure sensor installed in the low-temperature economizer inlet pipe, and the flue gas temperature information discharged from the low-temperature economizer is obtained by a temperature sensor on the low-temperature economizer flue gas outlet pipe. At the same time, the temperature sensors and temperature sensors at the water inlet and outlet of each low-temperature heating pipe respectively monitor the inlet and outlet water temperatures of the circulating water in the low-temperature heating pipe, and each sensor transmits the collected data to the intelligent control unit in real time; Data analysis and control decision-making steps: After receiving the sensor data, the intelligent control unit substitutes the real-time data into the control model, analyzes the deviation between the current flue gas waste heat recovery amount and the target value range, and comprehensively judges the operating status of the system based on the comparison results of the current operating parameters of each component and the threshold value. According to the control model, the adjustment amount of the operating parameters of each component required to make the flue gas waste heat recovery amount reach the target value range is calculated. When it is detected that the flue gas temperature discharged from the low-temperature economizer is higher than the upper limit of the target value range, and it is analyzed that it is caused by insufficient water circulation in the low-temperature economizer, the intelligent control unit calculates the speed increase of the circulating water pump and the opening adjustment of the relevant valves according to the control model; Instruction execution and effect verification steps: The intelligent control unit generates control instructions according to the regulation decision and sends them to the corresponding components. The circulating water pump, low-temperature economizer bypass valve, pressurized water pump, each low-temperature adder inlet valve, low-temperature adder bypass valve, and low-temperature adder outlet valve components adjust their operating status according to the instructions to achieve online regulation of the flue gas waste heat recovery amount. After the regulation action is executed, the system operating parameters are continuously monitored through various sensors, especially the temperature sensor on the flue gas outlet pipe of the low-temperature economizer detects the change in the exhaust flue gas temperature, and feeds back the new operating data to the intelligent control unit to determine whether the flue gas waste heat recovery amount reaches the target value range. If not, repeat the above data analysis and regulation decision steps as well as the instruction execution and effect verification steps until the target value range is reached. In the whole process, the intelligent control unit regularly stores the system operation data, uses the data analysis function to continuously optimize the control model, and at the same time uses data backtracking to troubleshoot possible system failures to ensure stable and efficient operation of the system.

[0012] Furthermore, in the data analysis and control decision-making step, when the intelligent control unit determines that the water circulation volume in the low-temperature economizer needs to be adjusted, in addition to controlling the circulating water pump and related valves, it will also use the expert system algorithm built into the intelligent control unit based on the low-temperature economizer inlet flue gas temperature, pressure and current operating load parameters to predict the impact of adjusting the water circulation volume on the entire system, such as the impact on the operating parameters of the downstream equipment of the electrostatic precipitator and induced draft fan; if it is predicted that it may have an adverse impact on the downstream equipment, the intelligent control unit will recalculate the adjustment strategy, and by fine-tuning the operating parameters of other components, while achieving the flue gas waste heat recovery control target, minimize the negative impact on other parts of the system to ensure stable and efficient operation of the entire system.

[0013] Furthermore, in the instruction execution and effect verification steps, if the flue gas waste heat recovery amount still does not reach the target value range after multiple adjustments, the intelligent control unit will start the fault diagnosis program; the fault diagnosis program first verifies the accuracy of each sensor data. If the sensor data is found to be abnormal, a sensor fault alarm is promptly issued and a sensor replacement prompt is given; if the sensor data is normal, a comprehensive inspection is performed on the operating status of each component, and by comparing the electrical parameters and mechanical operating sound characteristics during normal operation, it is determined whether there is a component failure; if a component failure is detected, the intelligent control unit will issue a corresponding fault alarm and locate the fault location, and provide preliminary solution suggestions based on the fault type, so that maintenance personnel can quickly repair the fault and restore the normal operation of the system to ensure that the flue gas waste heat recovery amount can be accurately regulated.

[0014] Furthermore, in the system preparation and parameter setting steps, the intelligent control unit can also interact with external meteorological monitoring equipment to obtain real-time meteorological data such as ambient temperature, humidity, and atmospheric pressure; these meteorological data are used as important reference factors when determining the target value range and control model of flue gas waste heat recovery; when the ambient temperature is low, the target value of flue gas waste heat recovery is appropriately lowered to avoid excessive cooling of the flue gas and causing condensation water problems in subsequent equipment; when the atmospheric pressure is low, the operating parameters of the system are adjusted according to the gas state equation to ensure that the flow and heat exchange process of the flue gas in the low-temperature economizer proceed normally, thereby improving the system's adaptability and stability to different environmental conditions.

[0015] It can be seen from the above technical solutions that the beneficial effects of the present invention are: Through the coordinated work of the intelligent control unit and various sensors and components, the operating parameters can be adjusted in real time according to different working conditions, the amount of flue gas waste heat recovery can be accurately controlled to reach the target value range, and energy utilization efficiency can be improved.

[0016] During the regulation process, the system can predict the impact on downstream equipment, reduce the negative impact of waste heat recovery adjustments on downstream equipment such as electrostatic precipitators and induced draft fans, and ensure stable and efficient operation of the entire thermal system.

[0017] The characteristics of components such as the low-temperature economizer bypass valve ensure that the system can still operate normally when the low-temperature economizer is maintained or fails, thereby improving system reliability; functions such as the variable frequency speed regulation of the circulating water pump enhance the system's adaptability to different working conditions and improve its flexibility.

[0018] The variable frequency speed control of the circulating water pump reduces mechanical wear, and the automatic cleaning device of the low-temperature economizer ensures heat exchange efficiency, all of which help to extend the service life of the equipment.

[0019] The data storage module facilitates data storage and analysis, and provides support for optimizing control strategies, etc. The fault diagnosis program can detect and locate faults in a timely manner, provide solution suggestions, and improve system operation and maintenance efficiency.

[0020] The intelligent control unit interacts with external meteorological monitoring equipment and adjusts system operating parameters based on meteorological data, so that the system can operate stably under different environmental conditions and avoid problems caused by environmental factors, such as condensation water. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the flue gas waste heat recovery system for wide channel plate low temperature economizer regulation.

[0022] In the figure: 1. air preheater; 2. low-temperature economizer; 3. electrostatic precipitator; 4. induced draft fan; 5. absorption tower; 6. wet electrostatic precipitator; 7. chimney; 8. low-pressure heating pipe; 9. heater; 10. low-pressure economizer outlet valve; 11. circulating water pump; 12. low-pressure heating inlet valve; 13. low-pressure heating split valve; 14. low-pressure heating bypass valve; 15. low-pressure heating outlet valve; 16. booster water pump; 17. low-pressure economizer inlet valve; 18. low-pressure economizer bypass valve. DETAILED DESCRIPTION

[0023] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. The implementation conditions used in the examples can be further adjusted according to the conditions of the manufacturer, and the implementation conditions not described are usually conventional experimental conditions.

[0024] Referring to 1, the implementation method of the online control system and method for adjusting the flue gas waste heat recovery amount of the wide channel plate type low temperature economizer is as follows: Flue gas treatment main process components Air preheater 1: As the front-end equipment of the flue gas waste heat recovery system, its main function is to use the waste heat of the flue gas at the tail of the boiler to heat the air required for combustion and improve the thermal efficiency of the boiler. The outlet of air preheater 1 is connected to the inlet of low-temperature economizer 2, so that the flue gas after preliminary heat exchange can smoothly enter the low-temperature economizer for further waste heat recovery.

[0025] Low-temperature economizer 2: This is one of the key equipment in the whole system, used to recover the waste heat in the flue gas and heat the circulating water. Its internal structure adopts a wide channel plate design, which helps to reduce the resistance on the flue gas side, improve the heat exchange efficiency, and also facilitates internal cleaning and maintenance. The flue gas outlet of the low-temperature economizer 2 is connected to the flue gas inlet of the electrostatic precipitator 3, and the flue gas after waste heat recovery is transported to the electrostatic precipitator for the next step of treatment.

[0026] Electrostatic precipitator 3: Responsible for removing particulate matter in the flue gas, reducing smoke and dust emissions, and protecting the environment. Its working principle is to use the electric field force to charge the particulate matter in the flue gas, and then move to the dust collecting electrode under the action of the electric field and settle down. The flue gas outlet of the electrostatic precipitator 3 is connected to the flue gas inlet of the absorption tower 5 through the induced draft fan 4. The induced draft fan 4 provides power for the transportation of the flue gas to ensure that the flue gas can flow smoothly in the system.

[0027] Absorption tower 5: It is mainly used to absorb harmful gases such as sulfur dioxide in the flue gas to achieve flue gas desulfurization. The absorption tower 5 is usually equipped with a spraying device, which sprays the absorbent to fully contact the flue gas to produce a chemical reaction, thereby removing harmful gases. The flue gas outlet of the absorption tower 5 is connected to the flue gas inlet of the wet electrostatic precipitator 6 to further purify the flue gas.

[0028] Wet electrostatic precipitator 6: deeply purifies the flue gas after being treated by the absorption tower, removes fine particles, acid mist, heavy metals and other pollutants, and ensures that the flue gas emissions meet environmental protection standards. The flue gas outlet of the wet electrostatic precipitator 6 is connected to the flue gas inlet of the chimney 7, and the purified flue gas is finally discharged into the atmosphere through the chimney.

[0029] A pressure sensor is installed on the inlet pipe of low-temperature economizer 2 to monitor the flue gas pressure entering the low-temperature economizer in real time and provide data support for the intelligent control of the system. A temperature sensor is installed on the flue gas outlet pipe of low-temperature economizer 2 to accurately detect the flue gas temperature discharged from the low-temperature economizer. This temperature data is crucial for judging the heat exchange effect of the low-temperature economizer and subsequent control decisions.

[0030] Low-temperature economizer outlet valve 10 and low-temperature economizer inlet valve 17: installed at the water outlet and water inlet of low-temperature economizer 2 respectively, used to control the inlet and outlet of circulating water in the low-temperature economizer. The opening and closing state and opening size of these two valves directly affect the water circulation volume and heat exchange process in the low-temperature economizer.

[0031] The outlet of the low-temperature economizer outlet valve 10 and the inlet of the low-temperature economizer inlet valve 17 are connected to a bypass pipe. A circulating water pump 11 and a low-temperature economizer bypass valve 18 are provided on the bypass pipe. The circulating water pump 11 provides power for the flow of circulating water in the bypass pipe, and its operating state can be adjusted according to system requirements to achieve flexible control of the water circulation volume in the low-temperature economizer. The low-temperature economizer bypass valve 18 is used to control the on-off and flow rate of the bypass pipe. When it is necessary to adjust the working state of the low-temperature economizer or perform maintenance, it can be achieved by operating the valve.

[0032] A pressure water pump 16 is installed on the inlet pipe of the low-temperature economizer inlet valve 17. The function of the pressure water pump 16 is to increase the circulating water pressure entering the low-temperature economizer, ensure that the circulating water can flow fully in the low-temperature economizer, and improve the heat exchange efficiency.

[0033] The circulating water inlet of the three groups of low-pressure heating pipes 8 is provided with a low-pressure heating inlet valve 12, and the low-pressure heating inlet valve 12 is connected to the low-pressure bypass inlet valve 17 through a pipeline with the low-pressure heating inlet valve 12 and the low-pressure heating bypass valve 14. The opening and closing of the low-pressure heating inlet valve 12 can control whether the circulating water enters the low-pressure heating pipe 8 for heat exchange. The low-pressure heating bypass valve 14 can adjust the distribution ratio of the circulating water between the low-pressure heating pipe 8 and the bypass, and optimize the heat exchange effect according to the actual working conditions.

[0034] The low-pressure addition inlet valve 12 is connected to the low-pressure addition inlet valve 17 through a branch pipeline with two sets of low-pressure addition pipes 8 and a low-pressure addition outlet valve 15. The low-pressure addition outlet valve 15 is used to control the outflow of circulating water in the low-pressure addition pipe 8, and works in conjunction with the low-pressure addition inlet valve 12 to achieve precise control of the water circulation in the low-pressure addition pipe 8.

[0035] The pipeline connected to the low-pressure injection inlet valve 12 and the low-pressure injection split valve 13 is connected to a water supply pipeline with a low-pressure injection pipe 8. The water supply pipeline can add circulating water to the low-pressure injection pipe 8 when the system needs it, thereby ensuring the normal operation of the system.

[0036] Air heater 9: The outlet pipe branch of the low-temperature economizer 2 can flow directly into the air heater 9, and the hot water at the outlet of the low-temperature economizer can be used as a heat source for the air heater to increase the air temperature. For example, it can be used to improve the ambient temperature in the factory in winter. The outlet pipe of the air heater 9 is connected to the low-temperature inlet valve 12, so that the circulating water after heat exchange in the air heater returns to the system circulation.

[0037] Temperature sensor: Temperature sensors are installed at the water inlet and outlet of each set of low-pressure heating pipes 8 to monitor the temperature change of circulating water in the low-pressure heating pipes in real time. By monitoring the temperature difference between the water inlet and the water outlet, the heat exchange effect of the low-pressure heating pipes can be intuitively understood, providing a basis for system regulation. Intelligent control components Intelligent control unit: This is the core control part of the whole system, which is electrically connected to the pressure sensor, temperature sensor, circulating water pump 11, low-pressure bypass valve 18, booster water pump 16, low-pressure inlet valves 12, low-pressure bypass valve 14, low-pressure outlet valve 15 and temperature sensors. The intelligent control unit has a built-in control model based on the relationship between the flue gas waste heat recovery amount and the operating parameters of each component under different working conditions. The model is established through a large number of experiments and actual operation data. The intelligent control unit can calculate the optimal operating parameter adjustment strategy through the control model based on the data fed back by the pressure sensor, temperature sensor and the temperature sensors related to each low-pressure pipe, and then control the operating status of each component to achieve online precise regulation of the flue gas waste heat recovery amount of the low-temperature economizer.

[0038] Data storage module: connected to the intelligent control unit, using a large-capacity hard disk, capable of storing at least one year of system operation data, including but not limited to historical monitoring data of each sensor, switch and operation parameter records of each valve and water pump, and flue gas waste heat recovery data at different times. At the same time, the data storage module has a data encryption function to ensure data security and confidentiality and prevent data leakage. By analyzing the stored historical data, the trend of system operation status changes can be traced, providing strong data support for optimizing control strategies, predicting equipment maintenance cycles, and troubleshooting, further improving the reliability and stability of the system.

[0039] Online Control Method System preparation and parameter setting steps Start the wide-channel plate-type low-temperature economizer to adjust the online control system of flue gas waste heat recovery, and set the target value range of flue gas waste heat recovery under different working conditions in the intelligent control unit. These target value ranges are determined based on multiple factors such as power generation efficiency requirements, environmental emission standards, and equipment operation safety. When the power generation efficiency requirements are high, the target value of flue gas waste heat recovery can be appropriately increased; in areas with strict environmental emission standards, it is necessary to ensure that the flue gas waste heat recovery is sufficient to make the flue gas temperature and pollutant content meet the standards; at the same time, the safety of equipment operation must also be considered to avoid equipment overheating and overpressure problems caused by excessive recovery of waste heat.

[0040] When setting the target value range, it is necessary to classify and analyze different working conditions. For example, according to the different boiler loads, the corresponding flue gas waste heat recovery target value range is determined. Under high load conditions, the boiler generates more flue gas and waste heat, so a higher waste heat recovery target value can be set, but the equipment's bearing capacity must also be considered; under low load conditions, the target value should be appropriately lowered to ensure stable operation of the system.

[0041] The operating parameter thresholds related to each component are input into the intelligent control unit. These thresholds include but are not limited to the pressure threshold of the pressure sensor, the temperature threshold of the temperature sensor, the opening threshold of each valve, and the operating parameter threshold of the water pump. When the system operating parameters exceed these thresholds, the intelligent control unit will take corresponding control measures to ensure the safe and stable operation of the system.

[0042] At the same time, the control model of the relationship between the flue gas waste heat recovery amount and the operating parameters of each component, which is established based on a large amount of experimental and actual operation data, is input into the intelligent control unit. This control model is the key to the system's precise control. It describes how changes in the operating parameters of each component affect the flue gas waste heat recovery amount under different operating conditions. The model may include the relationship between the speed of the circulating water pump and the circulating water flow in the low-temperature economizer, the relationship between the opening of the low-temperature bypass valve and the amount of flue gas passing through the low-temperature economizer, etc. By continuously optimizing the model, the control accuracy and adaptability of the system can be improved.

[0043] Calibrate each sensor to ensure measurement accuracy. The calibration process includes comparing and adjusting pressure sensors, temperature sensors, etc. using standard instruments. For example, for pressure sensors, high-precision pressure gauges can be used to calibrate them at different pressure values, record the deviation between the sensor measurement value and the standard value, and reduce the deviation by adjusting the sensor parameters or algorithms so that its measurement accuracy meets the system requirements. For temperature sensors, a constant temperature bath and other equipment can be used to provide a standard temperature environment for calibrating the sensor. Accurate measurement of sensors is the basis for the system to achieve precise control. Only by accurately obtaining data such as flue gas pressure, temperature, and circulating water temperature can the intelligent control unit make correct control decisions based on these data.

[0044] Real-time data collection steps Flue gas pressure data collection: The flue gas pressure data entering the low-temperature economizer is collected in real time through the pressure sensor installed in the inlet pipe of the low-temperature economizer 2. The pressure sensor converts the sensed pressure signal into an electrical signal and transmits it to the intelligent control unit. The intelligent control unit monitors and processes these data in real time, such as calculating the average value of the pressure, the fluctuation range and other statistical parameters to understand the changes in the flue gas pressure. Flue gas pressure data is very important for judging the operating status of the system. For example, an abnormal increase in pressure may indicate that the system is blocked or has other problems. Too low pressure may affect the flow and heat exchange effect of the flue gas.

[0045] Flue gas temperature information acquisition: The temperature sensor on the flue gas outlet pipe of low-temperature economizer 2 is used to obtain the flue gas temperature information discharged from the low-temperature economizer. The temperature sensor uses high-precision thermocouples or thermal resistors and other components to accurately measure the temperature of high-temperature flue gas. These temperature data are transmitted to the intelligent control unit in real time, and the intelligent control unit judges it according to the preset temperature threshold. If the exhaust flue gas temperature is too high, it may mean that the heat exchange efficiency of the low-temperature economizer has decreased and needs to be adjusted; if the temperature is too low, it may have an adverse effect on subsequent equipment, such as causing condensation water in the absorption tower and other problems.

[0046] Monitoring of circulating water temperature in low-pressure heating pipes: The temperature sensors at the water inlet and outlet of each low-pressure heating pipe 8 monitor the inlet and outlet water temperatures of the circulating water in the low-pressure heating pipes respectively. By monitoring the water inlet temperature, the initial temperature of the circulating water entering the low-pressure heating pipe can be understood, and combined with the water outlet temperature, the actual heat exchange effect of the low-pressure heating pipe can be calculated. The real-time collection and transmission of these temperature data provide a basis for the intelligent control unit to judge the working status of the low-pressure heating pipe. For example, when the inlet and outlet water temperature difference is too small, it may indicate that there is dirt in the low-pressure heating pipe that affects the heat exchange, or there is insufficient circulating water flow.

[0047] Data analysis and control decision-making steps After receiving the sensor data, the intelligent control unit substitutes the real-time data into the control model. For example, the collected data such as flue gas pressure, temperature, low-pressure pipe circulating water inlet and outlet temperature are input into the control model to calculate the actual value of the flue gas waste heat recovery under the current operating conditions. Then, the actual value is compared with the preset target value range to analyze the deviation between the current flue gas waste heat recovery and the target value range. If the actual value is higher than the upper limit of the target value range, it means that the waste heat recovery is too much, and it may be necessary to reduce the heat exchange of the low-temperature economizer; if the actual value is lower than the lower limit of the target value range, measures need to be taken to increase the waste heat recovery.

[0048] At the same time, a comprehensive judgment is made based on the comparison results of the current operating parameters of each component with the threshold. For example, check whether the current speed of the circulating water pump 11 is within the set speed threshold range, whether the opening of the low-voltage bypass valve 18 is normal, etc. If the operating parameters of a component exceed the threshold, it may affect the normal operation of the system and needs to be adjusted in time.

[0049] According to the control model and the deviation analysis results, the adjustment amount of the operating parameters of each component required to make the flue gas waste heat recovery reach the target value range is calculated. For example, when it is detected that the flue gas temperature discharged from the low-temperature economizer is higher than the upper limit of the target value range, and the analysis is that it is caused by insufficient water circulation in the low-temperature economizer, the intelligent control unit calculates the speed increase of the circulating water pump 11 according to the control model. Assuming that the current speed of the circulating water pump is 3000 rpm, according to the model calculation, the speed needs to be increased to 3500 rpm to increase the circulating water flow, improve the heat exchange efficiency, and reduce the exhaust flue gas temperature.

[0050] In addition to adjusting the speed of the circulating water pump, the valve opening may also be adjusted. For example, it is calculated that the low-temperature bypass valve 18 needs to be closed to a certain degree to allow more flue gas to pass through the low-temperature economizer for heat exchange, thereby reducing the flue gas temperature. When calculating the adjustment amount, the intelligent control unit will also consider the mutual influence between the components to ensure that the adjusted system can operate stably.

[0051] When the intelligent control unit determines that the water circulation volume in the low-temperature economizer 2 needs to be adjusted, in addition to controlling the circulating water pump 11 and related valves, it will also use the expert system algorithm built into the intelligent control unit based on the flue gas temperature and pressure at the inlet of the low-temperature economizer 2 and the current operating load parameters to predict the impact that the adjustment of the water circulation volume may have on the entire system, especially the impact on the operating parameters of the downstream equipment of the electrostatic precipitator 3 and the induced draft fan 4.

[0052] Increasing the amount of water circulation in the low-temperature economizer may cause the flue gas temperature to decrease, which in turn affects the electric field strength and dust removal efficiency in the electrostatic precipitator. The expert system algorithm predicts the extent of this impact based on pre-set rules and empirical data. If it is predicted that there may be adverse effects on downstream equipment, such as a decrease in the dust removal efficiency of the electrostatic precipitator, which may lead to excessive emissions, the intelligent control unit will recalculate the adjustment strategy. It is possible to fine-tune the operating parameters of other components, such as appropriately adjusting the speed of the induced draft fan to compensate for the change in flue gas flow caused by the decrease in flue gas temperature, while achieving the flue gas waste heat recovery control target, while minimizing the negative impact on other parts of the system and ensuring the stable and efficient operation of the entire system.

[0053] Instruction execution and effect verification steps The intelligent control unit generates control instructions based on the control decision and sends them to the corresponding components. For example, the instruction to adjust the speed of the circulating water pump 11 is sent to the driving motor controller of the circulating water pump, and the instruction to adjust the opening of the low-voltage bypass valve 18 is sent to the electric actuator of the valve. The control instructions contain specific operating parameters, such as the target speed of the circulating water pump, the target opening of the valve, etc.

[0054] Components such as the circulating water pump 11, the low-temperature economizer bypass valve 18, the booster water pump 16, each low-temperature economizer inlet valve 12, the low-temperature economizer bypass valve 14, and the low-temperature economizer outlet valve 15 adjust their operating status according to the instructions. The circulating water pump adjusts its speed according to the instructions to change the circulating water flow; the valve adjusts its opening according to the instructions to control the flow distribution of flue gas or circulating water. The coordinated work of each component realizes the online regulation of the flue gas waste heat recovery amount. For example, after the speed of the circulating water pump is increased, the circulating water flow in the low-temperature economizer increases, the heat exchange is more sufficient, and the flue gas waste heat recovery amount gradually increases; after the low-temperature economizer bypass valve is closed, more flue gas passes through the low-temperature economizer, further improving the waste heat recovery effect.

[0055] After the control action is executed, the system operating parameters are continuously monitored through various sensors, especially the temperature sensor on the flue gas outlet pipe of the low-temperature economizer 2 detects the change in the exhaust flue gas temperature. The new operating data is fed back to the intelligent control unit in real time, and the intelligent control unit determines whether the flue gas waste heat recovery amount reaches the target value range. If the exhaust flue gas temperature gradually decreases and approaches the target value range, it means that the control measures are effective; if it still does not reach the target value range, it is necessary to further analyze the reasons, which may be insufficient adjustment or other factors that are not considered in the system.

[0056] If the flue gas waste heat recovery amount still does not reach the target value range after multiple adjustments, the intelligent control unit will start the fault diagnosis program. The fault diagnosis program first verifies the accuracy of each sensor data to check whether the sensor is working properly. For example, compare whether the same parameter values ​​measured by different sensors are consistent, or check whether the sensor measurement value is within a reasonable range. If the sensor data is found to be abnormal, a sensor fault alarm will be issued in time and a sensor replacement will be prompted.

[0057] If the sensor data is normal, a comprehensive test will be conducted on the operating status of each component. By comparing the electrical parameters and mechanical operating sound characteristics during normal operation, it is determined whether there is a component failure. If a component failure is detected, the intelligent control unit will issue a corresponding fault alarm and locate the fault location. At the same time, it will provide preliminary solution suggestions based on the type of fault, so that maintenance personnel can quickly repair the fault and restore the normal operation of the system to ensure that the amount of flue gas waste heat recovery can be accurately regulated. For example, if the current of the circulating water pump motor is found to be abnormally high, it may indicate that there is a mechanical failure or motor overload in the water pump. The intelligent control unit will prompt the maintenance personnel to check whether the water pump impeller is blocked, whether the motor bearing is damaged, etc., and give corresponding maintenance instructions, such as cleaning the impeller, replacing the bearing and other operation suggestions. After the maintenance personnel troubleshoot and repair the fault according to the prompts of the intelligent control unit, they will start the system again for regulation until the amount of flue gas waste heat recovery reaches the target value range to ensure stable and efficient operation of the system.

[0058] Flow regulating baffle The flue gas inlet and outlet pipes of the low-temperature economizer 2 are respectively provided with flow regulating baffles, which are made of special high-temperature resistant and corrosion-resistant alloy materials. This material can operate stably for a long time in a high-temperature flue gas environment, withstand the scouring and corrosion of the flue gas, and ensure the service life and performance of the baffle. For example, materials such as nickel-based alloys or high-chromium alloys are used, which have excellent high-temperature resistance and can work normally at temperatures as high as 800°C or even higher. At the same time, they have good corrosion resistance and can resist the erosion of acidic gases and particulate matter in the flue gas.

[0059] The electric actuator of the flow regulating damper is equipped with a high-precision position feedback system, which can accurately feed back the actual opening of the damper to the intelligent control unit. Based on advanced algorithms, the intelligent control unit quickly and accurately controls the opening of the flow regulating damper according to the real-time operation requirements of the system, such as changes in boiler load, fluctuations in fuel quality, and changes in external ambient temperature, to achieve stepless regulation of the flue gas flow entering and exiting the low-temperature economizer.

[0060] For example, when the boiler load increases, more heat transfer is required. The intelligent control unit will send instructions to the electric actuator according to the preset control strategy to increase the flow adjustment damper opening, allowing more flue gas to pass through the low-temperature economizer to improve the heat exchange efficiency; when the fuel quality fluctuates and causes the flue gas calorific value to change, the damper opening can also be adjusted in time to ensure that the low-temperature economizer is always in the best working state. This dynamic adjustment method can enable the low-temperature economizer to always maintain the best heat exchange efficiency under various operating conditions, effectively improve the system's recovery and utilization rate of flue gas waste heat, and at the same time help stabilize the operating parameters of the entire thermal system and reduce the adverse effects of operating condition fluctuations on the equipment.

[0061] The circulating water pump 11 is a variable frequency speed regulating water pump, and its speed can be continuously adjusted within the range of 0-5000 rpm. The intelligent control unit accurately controls the speed of the circulating water pump according to the real-time operating parameters of the system and the target value of the flue gas waste heat recovery. When the flue gas waste heat recovery is low, the speed of the circulating water pump is reduced to reduce energy consumption. For example, when the system detects that the current flue gas waste heat recovery has exceeded the target value range and there is a large margin, the intelligent control unit will reduce the speed of the circulating water pump and reduce the circulating water flow, thereby reducing the heat exchange intensity of the low-temperature economizer, so that the flue gas waste heat recovery is gradually reduced to within the target value range, while reducing the energy consumption of the water pump.

[0062] When it is necessary to increase the amount of flue gas waste heat recovery, increase the speed of the circulating water pump, increase the circulating water flow rate, and make the heat exchange in the low-temperature economizer 2 more sufficient. For example, when the ambient temperature is low in winter, in order to improve the boiler efficiency and waste heat recovery utilization rate, the intelligent control unit will increase the speed of the circulating water pump, increase the circulating water flow rate in the low-temperature economizer, enhance the heat exchange effect, increase the amount of flue gas waste heat recovery, and provide more thermal energy for the plant. This variable frequency speed control method can dynamically adjust the circulating water flow rate according to actual needs, improve the energy utilization efficiency of the system, and at the same time reduce the mechanical wear of the water pump and extend the service life of the circulating water pump. Because compared with traditional fixed speed water pumps, variable frequency speed regulation water pumps can avoid frequent starting and stopping, reduce the impact current and mechanical wear of the water pump at the moment of starting, and make the water pump run more smoothly and reliably.

[0063] The low-temperature economizer bypass valve 18 adopts an electric butterfly valve, which has good sealing performance and a leakage rate of less than 0.1%. This high sealing performance can effectively prevent the flue gas from leaking between the bypass pipe and the low-temperature economizer, ensuring the operating efficiency of the system and the flue gas treatment effect. The electric butterfly valve has a fast switching speed and can complete the full opening or full closing action within 1-5 seconds, and can accurately control the valve opening, and the opening adjustment accuracy can reach ±1%. This enables the system to respond quickly when it is necessary to quickly switch the working state of the low-temperature economizer or make emergency adjustments. For example, when the low-temperature economizer fails and needs to be bypassed immediately, the electric butterfly valve can be opened quickly to ensure that the flue gas passage is unobstructed and does not affect the normal operation of the entire system.

[0064] The intelligent control unit controls the opening of the low-energy bypass valve 18 according to the system operating status. When it is necessary to increase the flue gas processing capacity of the low-temperature economizer 2, the low-energy bypass valve 18 is closed to allow more flue gas to pass through the low-temperature economizer. For example, when the power generation load is high and the waste heat recovery efficiency needs to be improved, the intelligent control unit will calculate based on the system parameters, close the low-energy bypass valve, increase the amount of flue gas passing through the low-temperature economizer, increase the amount of waste heat recovery, provide more heat energy for subsequent equipment, or reduce the flue gas emission temperature. When the low-temperature economizer needs maintenance or fails, the low-energy bypass valve 18 is quickly opened to ensure that the system flue gas passage is unobstructed, thereby improving the reliability and flexibility of the system and enabling the system to maintain basic operation during equipment maintenance or failure, reducing the impact on production.

[0065] An automatic cleaning device is provided inside the low-temperature economizer 2, and the automatic cleaning device includes a plurality of high-pressure nozzles, which are evenly distributed between the plates of the low-temperature economizer, and the spray direction of the nozzles is toward the plate surface. When the intelligent control unit detects that the plate dirt accumulation reaches a certain level according to the preset cleaning cycle or according to the plate pressure difference sensor, the automatic cleaning device is started. For example, it is preset to perform cleaning once every certain period of operation, or when the plate pressure difference sensor detects that the pressure difference on both sides of the plate exceeds the set threshold, the automatic cleaning is started.

[0066] The high-pressure nozzle sprays high-pressure water to clean the plates, remove dirt and impurities on the surface of the plates, and ensure the heat exchange efficiency of the plates. The pressure of the high-pressure water flow can be adjusted according to the stubbornness of the dirt, generally between 1-10MPa. The sewage generated during the cleaning process is discharged through a special drainage pipe to avoid pollution to other parts of the system, ensuring the long-term stable and efficient operation of the low-temperature economizer. At the same time, regular cleaning can also extend the service life of the low-temperature economizer, reduce equipment corrosion and damage caused by dirt accumulation, and improve the reliability and economy of the entire system.

[0067] Data exchange with external meteorological monitoring equipment The intelligent control unit can exchange data with external meteorological monitoring equipment to obtain real-time meteorological data such as ambient temperature, humidity, and atmospheric pressure. These meteorological data are used as important reference factors when determining the target value range and control model of flue gas waste heat recovery. For example, when the ambient temperature is low, the target value of flue gas waste heat recovery should be appropriately reduced to avoid excessive cooling of the flue gas and causing condensation problems in subsequent equipment. Because when the ambient temperature is low, if the flue gas waste heat recovery is too large, the flue gas temperature may drop below the dew point temperature, generating condensation in subsequent equipment such as absorption towers and chimneys, corroding the equipment and affecting the normal operation of the system.

[0068] When the atmospheric pressure is low, the system's operating parameters are adjusted according to the gas state equation to ensure that the flue gas flow and heat exchange process in the low-temperature economizer proceed normally. For example, when the atmospheric pressure decreases, the gas volume will expand, which may affect the flow rate and distribution of the flue gas in the pipeline. The intelligent control unit will adjust the speed of the induced draft fan, the opening of the flow regulating damper and other parameters according to the meteorological data to ensure that the flue gas has a suitable flow rate and residence time in the low-temperature economizer, improve the heat exchange efficiency, and thus improve the system's adaptability and stability to different environmental conditions, so that the system can achieve efficient and stable operation under various meteorological conditions, and ensure the economy and environmental protection of the power generation process.

Claims

1. Wide channel plate type low temperature economizer adjusts flue gas waste heat recovery amount online control system, characterized in that: include: The main flow assembly of flue gas treatment comprises an air preheater (1), a low-temperature economizer (2), an electrostatic precipitator (3), an induced draft fan (4), an absorption tower (5), a wet electrostatic precipitator (6) and a chimney (7). The inlet of the low-temperature economizer (2) is connected to the outlet of the air preheater (1). The flue gas outlet of the low-temperature economizer (2) is connected to the flue gas inlet of the electrostatic precipitator (3). The flue gas of the electrostatic precipitator (3) is transported to the flue gas inlet of the absorption tower (5) through the induced draft fan (4). The flue gas outlet of the absorption tower (5) is connected to the flue gas inlet of the wet electrostatic precipitator (6). The flue gas outlet of the wet electrostatic precipitator (6) is connected to the flue gas inlet of the chimney (7). A pressure sensor is installed on the inlet pipe of the low-temperature economizer (2) to monitor the flue gas pressure entering the low-temperature economizer. A temperature sensor is installed on the flue gas outlet pipe of the low-temperature economizer (2) to detect the flue gas temperature discharged from the low-temperature economizer. Low-temperature economizer water circulation component: The water outlet and water inlet of the low-temperature economizer (2) are respectively provided with a low-temperature economizer outlet valve (10) and a low-temperature economizer inlet valve (17); the outlet of the low-temperature economizer outlet valve (10) and the inlet of the low-temperature economizer inlet valve (17) are connected to a bypass pipe, and a circulating water pump (11) and a low-temperature economizer bypass valve (18) are provided on the bypass pipe; a pressurized water pump (16) is installed on the inlet pipe of the low-temperature economizer inlet valve (17); the circulating water inlets of the three groups of low-temperature economizer pipes (8) are provided with low-temperature addition inlet valves (12); the low-temperature addition inlet valves (12) are connected to the low-temperature economizer via a pipe having the low-temperature addition inlet valve (12) and the low-temperature bypass valve (14). The economizer inlet valve (17) is connected to the low-pressure economizer inlet valve (12) through a branch pipeline with two groups of low-pressure heating pipes (8) and a low-pressure heating outlet valve (15). The pipeline connected to the low-pressure heating inlet valve (12) and the low-pressure heating split valve (13) is connected to a water supply pipeline with a low-pressure heating pipe (8). The outlet pipe branch of the low-temperature economizer (2) can directly flow into the heater (9), and the outlet pipe of the heater (9) merges into the low-pressure economizer inlet valve (12). A temperature sensor and a temperature sensor are respectively installed at the water inlet and the water outlet of each group of low-pressure heating pipes (8) to monitor the temperature change of the circulating water in the low-pressure heating pipes; The intelligent control component comprises an intelligent control unit, which is electrically connected to the pressure sensor, the temperature sensor, the circulating water pump (11), the low-temperature economizer bypass valve (18), the booster water pump (16), each low-temperature economizer inlet valve (12), the low-temperature economizer bypass valve (14), the low-temperature economizer outlet valve (15), and each temperature sensor and temperature sensor. The intelligent control unit has a built-in control model based on the relationship between the flue gas waste heat recovery amount and the operating parameters of each component under different working conditions. The intelligent control unit can calculate the optimal operating parameter adjustment strategy through the control model based on the data fed back by the pressure sensor, the temperature sensor and the temperature sensors related to each low-temperature economizer pipe, thereby controlling the operating status of the circulating water pump (11), the low-temperature economizer bypass valve (18), the booster water pump (16), each low-temperature economizer inlet valve (12), the low-temperature economizer bypass valve (14), and the low-temperature economizer outlet valve (15), thereby realizing online precise control of the flue gas waste heat recovery amount of the low-temperature economizer. At the same time, the intelligent control unit also has data storage and analysis functions, and can regularly store and analyze system operation data to optimize the control model and troubleshoot system failures.

2. An online control method for adjusting the flue gas waste heat recovery amount of a wide channel plate type low temperature economizer according to claim 1, characterized in that: The following steps are involved: System preparation and parameter setting steps: Start the wide-channel plate-type low-temperature economizer to adjust the flue gas waste heat recovery amount online control system, set the target value range of the flue gas waste heat recovery amount under different working conditions in the intelligent control unit. These target value ranges are determined based on multiple factors such as power generation efficiency requirements, environmental emission standards, and equipment operation safety. At the same time, the operating parameter thresholds related to each component and the control model of the relationship between the flue gas waste heat recovery amount and the operating parameters of each component based on a large amount of experimental and actual operation data are input into the intelligent control unit, and each sensor is calibrated to ensure measurement accuracy; Real-time data collection step: a pressure sensor installed on the inlet pipe of the low-temperature economizer (2) is used to collect the flue gas pressure data entering the low-temperature economizer in real time, and a temperature sensor on the flue gas outlet pipe of the low-temperature economizer (2) is used to obtain the flue gas temperature information discharged from the low-temperature economizer. At the same time, the temperature sensors and temperature sensors at the water inlet and outlet of each low-temperature heating pipe (8) respectively monitor the inlet and outlet water temperatures of the circulating water in the low-temperature heating pipe, and each sensor transmits the collected data to the intelligent control unit in real time; Data analysis and control decision-making steps: After receiving the sensor data, the intelligent control unit substitutes the real-time data into the control model, analyzes the deviation between the current flue gas waste heat recovery amount and the target value range, combines the comparison results of the current operating parameters of each component and the threshold value, comprehensively judges the operating state of the system, and calculates the adjustment amount of the operating parameters of each component required to make the flue gas waste heat recovery amount reach the target value range according to the control model. When it is detected that the flue gas temperature discharged from the low-temperature economizer is higher than the upper limit of the target value range, and it is analyzed that it is caused by insufficient water circulation in the low-temperature economizer, the intelligent control unit calculates the speed increase of the circulating water pump (11) and the opening adjustment amount of the relevant valves according to the control model; Instruction execution and effect verification steps: The intelligent control unit generates a control instruction according to the control decision and sends it to the corresponding components. The circulating water pump (11), the low-temperature economizer bypass valve (18), the booster water pump (16), each low-temperature adder inlet valve (12), the low-temperature adder bypass valve (14), and the low-temperature adder outlet valve (15) components adjust their operating states according to the instructions to achieve online control of the flue gas waste heat recovery amount. After the control action is executed, the system operating parameters are continuously monitored through various sensors, especially the temperature sensor on the flue gas outlet pipe of the low-temperature economizer (2) detects the change in the exhaust flue gas temperature, and feeds back the new operating data to the intelligent control unit to determine whether the flue gas waste heat recovery amount reaches the target value range. If not, the above data analysis and control decision steps and instruction execution and effect verification steps are repeated until the target value range is reached. In the whole process, the intelligent control unit regularly stores the system operation data, uses the data analysis function to continuously optimize the control model, and at the same time uses data backtracking to check possible system faults to ensure stable and efficient operation of the system.

3. The wide channel plate type low temperature economizer online control system for adjusting flue gas waste heat recovery according to claim 1 is characterized in that: The intelligent control unit is connected to a data storage module, which uses a large-capacity hard disk and can store at least one year's system operation data, including but not limited to the historical monitoring data of each sensor, the switch and operation parameter records of each valve and water pump, and the flue gas waste heat recovery data at different times; at the same time, the data storage module has a data encryption function to ensure the security and confidentiality of the data and prevent data leakage; by analyzing the stored historical data, the changing trend of the system operation status can be traced, providing strong data support for optimizing control strategies, predicting equipment maintenance cycles and troubleshooting, and further improving the reliability and stability of the system.

4. The wide channel plate type low temperature economizer online control system for adjusting flue gas waste heat recovery according to claim 1 is characterized in that: The flue gas inlet and outlet pipes of the low-temperature economizer (2) are respectively provided with flow regulating baffles, which are made of special high-temperature resistant and corrosion-resistant alloy materials to ensure long-term stable operation in a high-temperature flue gas environment; its electric actuator is equipped with a high-precision position feedback system, which can accurately feed back the actual opening of the baffle to the intelligent control unit; the intelligent control unit is based on advanced algorithms and controls the opening of the flow regulating baffle quickly and accurately according to the real-time operation requirements of the system, such as changes in boiler load, fluctuations in fuel quality and changes in external ambient temperature, to achieve stepless regulation of the flue gas flow entering and exiting the low-temperature economizer; this dynamic regulation method can enable the low-temperature economizer to always maintain the best heat exchange efficiency under various operating conditions, effectively improve the system's recovery and utilization rate of flue gas waste heat, and at the same time help stabilize the operating parameters of the entire thermal system and reduce the adverse effects of operating condition fluctuations on the equipment.

5. The wide channel plate type low temperature economizer online control system for adjusting flue gas waste heat recovery according to claim 1 is characterized in that: The circulating water pump (11) is a variable frequency speed regulating water pump, the rotation speed of which can be continuously adjusted within the range of 0-5000 rpm; the intelligent control unit accurately controls the rotation speed of the circulating water pump (11) according to the real-time operating parameters of the system and the target value of the flue gas waste heat recovery amount; when the flue gas waste heat recovery amount is low, the rotation speed of the circulating water pump is reduced to reduce energy consumption; when the flue gas waste heat recovery amount needs to be increased, the rotation speed of the circulating water pump is increased to increase the circulating water flow rate, so that the heat exchange in the low-temperature economizer (2) is more sufficient; this variable frequency speed regulating control method can dynamically adjust the circulating water flow rate according to actual needs, improve the energy utilization efficiency of the system, and at the same time reduce the mechanical wear of the water pump and extend the service life of the circulating water pump.

6. The wide channel plate type low temperature economizer online control system for adjusting flue gas waste heat recovery according to claim 1 is characterized in that: The low-temperature economizer bypass valve (18) adopts an electric butterfly valve, which has good sealing performance and a leakage rate of less than 0.1%. The electric butterfly valve has a fast switching speed and can complete a full opening or full closing action within 1-5 seconds, and can accurately control the valve opening, with an opening adjustment accuracy of up to ±1%. The intelligent control unit controls the opening of the low-temperature economizer bypass valve (18) according to the system operation status. When it is necessary to increase the flue gas treatment capacity of the low-temperature economizer (2), the low-temperature economizer bypass valve (18) is closed to allow more flue gas to pass through the low-temperature economizer. When the low-temperature economizer needs maintenance or fails, the low-temperature economizer bypass valve (18) is quickly opened to ensure that the system flue gas passage is unobstructed, without affecting the normal operation of the entire system, thereby improving the reliability and flexibility of the system.

7. The wide channel plate type low temperature economizer online control system for adjusting flue gas waste heat recovery according to claim 1 is characterized in that: The low-temperature economizer (2) is internally provided with an automatic cleaning device, which includes a plurality of high-pressure nozzles, which are evenly distributed between the plates of the low-temperature economizer, and the spray direction of the nozzles is toward the surface of the plates; when the intelligent control unit detects that the accumulation of dirt on the plates reaches a certain level according to a preset cleaning cycle or according to the plate pressure difference sensor, the automatic cleaning device is started; the high-pressure nozzles spray high-pressure water flow to clean the plates, remove dirt and impurities on the surface of the plates, and ensure the heat exchange efficiency of the plates; at the same time, the sewage generated during the cleaning process is discharged through a special drainage pipe to avoid pollution to other parts of the system, thereby ensuring the long-term stable and efficient operation of the low-temperature economizer.

8. The method for online control of flue gas waste heat recovery amount of a wide channel plate type low temperature economizer according to claim 2 is characterized in that: In the data analysis and control decision-making step, when the intelligent control unit determines that the water circulation volume in the low-temperature economizer (2) needs to be adjusted, in addition to controlling the circulating water pump (11) and related valves, it will also use the expert system algorithm built into the intelligent control unit based on the flue gas temperature and pressure at the inlet of the low-temperature economizer (2) and the current operating load parameters to predict the impact that the adjustment of the water circulation volume may have on the entire system, such as the impact on the operating parameters of the downstream equipment such as the electrostatic precipitator (3) and the induced draft fan (4); if it is predicted that there may be an adverse impact on the downstream equipment, the intelligent control unit will recalculate the adjustment strategy and, by fine-tuning the operating parameters of other components, minimize the negative impact on other parts of the system while achieving the flue gas waste heat recovery control target, thereby ensuring stable and efficient operation of the entire system.

9. The method for online control of flue gas waste heat recovery amount of wide channel plate type low temperature economizer according to claim 2 is characterized in that: In the instruction execution and effect verification steps, if the flue gas waste heat recovery amount still does not reach the target value range after multiple adjustments, the intelligent control unit will start the fault diagnosis program; the fault diagnosis program first verifies the accuracy of each sensor data, and if the sensor data is found to be abnormal, a sensor fault alarm is issued in time and a sensor replacement is prompted; If the sensor data is normal, a comprehensive inspection will be conducted on the operating status of each component, and by comparing the electrical parameters and mechanical operating sound characteristics during normal operation, it will be determined whether there is a component failure. If a component failure is detected, the intelligent control unit will issue a corresponding fault alarm and locate the fault. At the same time, it will provide preliminary solution suggestions based on the fault type, so that maintenance personnel can quickly repair the fault, restore the normal operation of the system, and ensure that the amount of flue gas waste heat recovery can be accurately controlled.

10. The method for online control of flue gas waste heat recovery amount of wide channel plate type low temperature economizer according to claim 2, characterized in that: In the system preparation and parameter setting steps, the intelligent control unit can also exchange data with external meteorological monitoring equipment to obtain real-time meteorological data such as ambient temperature, humidity, and atmospheric pressure; these meteorological data are used as important reference factors when determining the target value range and control model of flue gas waste heat recovery; when the ambient temperature is low, the target value of flue gas waste heat recovery is appropriately reduced to avoid excessive cooling of the flue gas and causing condensation water problems in subsequent equipment; when the atmospheric pressure is low, the operating parameters of the system are adjusted according to the gas state equation to ensure that the flow and heat exchange process of the flue gas in the low-temperature economizer proceed normally, thereby improving the system's adaptability and stability to different environmental conditions.

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