Control method, controller and system for comprehensive cold end temperature of air pre-heater

Abstract

The invention relates to a control method, controller and system for the comprehensive cold end temperature of an air pre-heater, and relates to the technical field of power stations. The control method comprises the steps that the secondary air temperature at an inlet of the air pre-heater is obtained, and the flue gas temperature at an outlet of the air pre-heater is obtained; according to the sum of the secondary air temperature and the flue gas temperature, the comprehensive cold end temperature of the air pre-heater is determined; and under the condition that the comprehensive cold end temperature exceeds the preset range, the opening degree of an outdoor air taking baffle and the opening degree of an indoor air taking baffle are adjusted, so that the secondary air temperature is adjusted, and the comprehensive cold end temperature is controlled to be kept within the preset range. According to the method, the timeliness and accuracy of temperature control over the comprehensive cold end of the air pre-heater can be improved, the method can be used in winter and other seasons, the problem that ammonium bisulfate is condensed and blocked due to the fact that the comprehensive cold end of the air pre-heater is too low can be solved, finally, the station service power consumption rate of a unit is reduced, and the boiler efficiency is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power plants, and in particular to a control method, a controller and a system for controlling the comprehensive cold end temperature of an air preheater. Background Art

[0002] The air preheater is an important equipment in a thermal power plant, used to preheat the secondary air entering the boiler. The comprehensive cold end temperature of the air preheater needs to be controlled within a certain range to prevent the low-temperature corrosion of the heat storage element caused by the condensation of sulfuric acid in the flue gas, and the condensation of ammonium bisulfate in the flue gas from causing the air preheater to accumulate dust and become clogged.

[0003] In the related art, high-temperature auxiliary steam usually extracted from the thermal system of a thermal power plant is used to heat the cold air through a heater to increase the secondary air of the air preheater. This method will cause a waste of high-quality steam and is only suitable for use in winter. In other seasons, an indirect secondary air heater system is usually used, or the opening of the indoor and outdoor air intake dampers of the blower are manually adjusted to change the outlet temperature of the blower to adjust the secondary air of the air preheater. However, due to the rapid changes in ambient temperature in spring and autumn, and the large load variation range of thermal power units, the comprehensive cold end temperature changes frequently, and manual adjustment is inefficient, time-sensitive and inaccurate. Summary of the invention

[0004] In order to overcome the problems existing in the related art, the present application provides a control method, controller and system for the comprehensive cold end temperature of an air preheater.

[0005] According to a first aspect of the present application, a method for controlling the comprehensive cold end temperature of an air preheater is provided, comprising: Acquire the secondary air temperature at the inlet of the air preheater, and acquire the flue gas temperature at the outlet of the air preheater; Determining the comprehensive cold end temperature of the air preheater according to the sum of the secondary air temperature and the flue gas temperature; When the comprehensive cold end temperature exceeds the preset range, the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle are adjusted to adjust the secondary air temperature and control the comprehensive cold end temperature to remain within the preset range. The opening of the outdoor air intake baffle and the indoor air intake baffle can be continuously and arbitrarily adjusted between the fully closed opening and the fully open opening. The indoor air intake baffle is used to transport the hot air from the top of the boiler to the inlet of the air supply fan, and the outdoor air intake baffle is used to transport the cold air outside the boiler room to the inlet of the air supply fan. The air supply fan is used to mix the hot air and the cold air and transport the mixed air to the air preheater through the secondary air heater.

[0006] Optionally, obtaining the secondary air temperature at the inlet of the air preheater and obtaining the flue gas temperature at the outlet of the air preheater include: The secondary air temperature is obtained from the first temperature sensors at the air preheater inlet, there are at least three first temperature sensors, and the secondary air temperature is the middle value of the temperatures measured by all the first temperature sensors; The flue gas temperature is obtained from a second temperature sensor at an air preheater outlet, there are at least three second temperature sensors, and the flue gas temperature is the middle value of the temperatures measured by all the second temperature sensors.

[0007] Optionally, when the comprehensive cold end temperature exceeds a preset range, adjusting the opening of the outdoor air intake damper and the opening of the indoor air intake damper includes: The opening of the outdoor air intake baffle and the opening of the indoor air intake baffle are adjusted, and the sum of the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle is maintained at a first preset opening.

[0008] Optionally, when the comprehensive cold end temperature exceeds a preset range, adjusting the opening of the outdoor air intake damper and the opening of the indoor air intake damper includes: When the comprehensive cold end temperature is greater than the upper limit of the preset range, increasing the opening of the outdoor air intake damper and decreasing the opening of the indoor air intake damper; When the comprehensive cold-end temperature is less than the lower limit of the preset range, the opening of the indoor air intake damper is increased, and the opening of the outdoor air intake damper is decreased.

[0009] Optionally, the method further comprises: When the sum of the opening of the indoor air intake damper and the opening of the indoor air intake damper is greater than the second preset opening, the air supply fan is controlled to start.

[0010] Optionally, the method further comprises: When the deviation between the actual value of the opening degree of any one of the indoor air intake damper and the outdoor air intake damper and the command value is greater than a preset value, the control is terminated.

[0011] According to the second aspect of the present application, a controller for the comprehensive cold end temperature of an air preheater is provided, and the controller is used to execute the steps of the control method provided in the first aspect of the present application.

[0012] According to a third aspect of the present application, a control system for the integrated cold end temperature of an air preheater is provided, comprising: An outdoor air intake baffle, an indoor air intake baffle, a blower, a boiler, a secondary air heater, an air preheater, and a controller, wherein the secondary air heater is coupled to the outdoor air intake baffle and the indoor air intake baffle, the secondary air heater is connected to the air preheater, the air preheater is connected to the boiler, and the controller is connected to the outdoor air intake baffle and the indoor air intake baffle; The indoor air intake baffle is used to transport the hot air from the top of the boiler to the inlet of the blower; The outdoor air intake baffle is used to transport the cold air outside the boiler room to the inlet of the air blower; The blower is used to mix the hot air and the cold air and deliver the mixed air to the air preheater through the secondary air heater; The controller is used to execute the steps of the control method provided in the first aspect of the present application.

[0013] Optionally, the control system comprises: A first temperature sensor is provided at the inlet of the air preheater, and the controller is connected to the first temperature sensor.

[0014] Optionally, the control system comprises: A second temperature sensor is provided at the outlet of the air preheater, and the controller is connected to the second temperature sensor.

[0015] The above technical solution calculates the comprehensive cold end temperature of the air preheater by real-time monitoring of the secondary air temperature at the air preheater inlet and the flue gas temperature at the outlet, and automatically adjusts the opening of the outdoor air intake damper and the indoor air intake damper when the comprehensive cold end temperature exceeds the preset range, so as to accurately control the comprehensive cold end temperature to remain within the optimal range. At the same time, the technical solution adopts a continuously adjustable electric damper, which can more accurately control the secondary air temperature compared to the manual switch air intake damper. The above technical solution can effectively avoid the problem of the comprehensive cold end temperature of the air preheater being too high or too low due to changes in ambient temperature and unit load, thereby preventing the air preheater from low-temperature corrosion, blockage and other problems, and improving the thermal efficiency and economy of the boiler.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings: Figure 1 is a flow chart showing a method for controlling the comprehensive cold end temperature of an air preheater according to an exemplary embodiment; Figure 2 is a block diagram of a controller for integrated cold end temperature of an air preheater according to an exemplary embodiment; Figure 3 It is a structural diagram of a control system for the integrated cold end temperature of an air preheater according to an exemplary embodiment.

[0018] Reference numerals: The control system 300 of the integrated cold end temperature of the air preheater, the outdoor air intake damper 310, the indoor air intake damper 320, the boiler 330, the secondary air heater 340, the air preheater 350, the controller 200, the first temperature sensor 370, the second temperature sensor 380, and the air blower 390. DETAILED DESCRIPTION

[0019] The specific embodiments of the present application are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application and are not intended to limit the present application. When the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The terms "first", "second", etc. used in this application are to distinguish one element from another element and do not have order and importance.

[0020] In the related art, a secondary air heater is used to control the comprehensive cold end temperature of the air preheater. The secondary air heater is used to heat the secondary air at the inlet of the air preheater, thereby preventing the comprehensive cold end temperature of the air preheater from being too low. High-temperature steam of 250-300 degrees Celsius is extracted from the auxiliary steam system and enters the heat exchange tube inside the secondary air heater. After heat exchange, the cold air is heated to hot air of 40-50 degrees Celsius. The heated hot air will enter the air preheater and exchange heat with the high-temperature flue gas again. Finally, the hot air will be further heated to 290-330 degrees Celsius and then sent to the boiler combustion chamber.

[0021] However, in the above method, the secondary air heater consumes a large amount of high-quality steam, which affects the economic efficiency of the unit. The secondary air heater is frequently put into operation and stopped in spring and autumn, which increases the operation and maintenance cost.

[0022] In the related technology, in seasons other than winter, two methods of indoor and outdoor air intake are usually used. The secondary air intake method is switched by manual observation and judgment. When the temperature of the integrated cold end of the air preheater is too low, the staff opens the indoor air intake to extract the high-temperature air from the furnace top; when the temperature of the integrated cold end is too high, the staff opens the outdoor air intake to extract the low-temperature air from the outside.

[0023] However, the above method has poor timeliness and cannot accurately control the integrated cold end temperature in a timely manner. In addition, the air intake baffle can only be fully opened or fully closed, and cannot be continuously adjusted, and the adjustment accuracy is poor. When switching the air intake mode, it is easy to cause the integrated cold end temperature to be too high or too low.

[0024] In summary, the relevant technology has the problems of low adjustment accuracy, slow response speed and poor economy, and cannot effectively control the comprehensive cold end temperature of the air preheater.

[0025] In view of the deficiencies in the related art, the present application provides a method and system for controlling the comprehensive cold end temperature of an air preheater.

[0026] Figure 1 1 is a flow chart showing a method for controlling the comprehensive cold end temperature of an air preheater according to an exemplary embodiment. Figure 1 The method for controlling the comprehensive cold end temperature of the air preheater comprises the following steps: In step 110, the secondary air temperature at the inlet of the air preheater is obtained, and the flue gas temperature at the outlet of the air preheater is obtained; In step 120, the comprehensive cold end temperature of the air preheater is determined according to the sum of the secondary air temperature and the flue gas temperature; In step 130, when the combined cold end temperature exceeds a preset range, the opening of the outdoor air intake damper and the opening of the indoor air intake damper are adjusted to adjust the secondary air temperature and control the combined cold end temperature to remain within the preset range. The openings of the outdoor air intake damper and the indoor air intake damper are continuously and arbitrarily adjusted between a fully closed opening and a fully open opening. The indoor air intake damper is used to transport the hot air from the top of the boiler to the inlet of the air supply fan, and the outdoor air intake damper is used to transport the cold air outside the boiler room to the inlet of the air supply fan. The air supply fan is used to mix the hot air and the cold air and transport the mixed air to the air preheater through a secondary air heater.

[0027] Here, the air preheater is a device used in thermal power plants to preheat the secondary air entering the boiler. It heats the secondary air from a lower temperature to a higher temperature by exchanging heat with the high-temperature flue gas, and then sends it to the boiler for combustion with the fuel. The secondary air at the inlet of the air preheater is the air entering the air preheater, which needs to be heated to a higher temperature before entering the boiler for combustion. The flue gas at the outlet of the air preheater is the high-temperature flue gas discharged from the boiler, which exchanges heat with the secondary air to heat the secondary air.

[0028] The comprehensive cold end temperature of the air preheater is the sum of the secondary air temperature and the flue gas temperature. The comprehensive cold end temperature of the air preheater needs to be controlled within the preset range. If the comprehensive cold end temperature is too low, it will cause low-temperature corrosion of the air preheater and condensation of ammonium bisulfate and ash accumulation, reducing the heat exchange efficiency. If the comprehensive cold end temperature is too high, the boiler exhaust temperature will be too high, increasing exhaust heat loss and reducing boiler efficiency. According to industry standards, in order to prevent low-temperature corrosion and blockage of the air preheater, the preset range of the comprehensive cold end temperature can be 148±2 degrees Celsius.

[0029] The outdoor air intake damper is an adjustable electric damper installed outside the boiler room to control the amount of cold air sucked in from the outside. When the comprehensive cold end temperature is too high, the outdoor air intake damper will be opened wider to increase the amount of cold air sucked in from the outside, thereby reducing the secondary air temperature.

[0030] The indoor air intake damper is an adjustable electric damper installed on the top of the boiler room, which is used to control the amount of hot air sucked in from the top of the boiler. When the comprehensive cold end temperature is too low, the indoor air intake damper will be opened wider to increase the amount of high-temperature air sucked in from the top of the boiler, thereby increasing the secondary air temperature. The air temperature at the top of the boiler is relatively high (about 40-50 degrees Celsius), and using this part of hot air can effectively increase the secondary air temperature, thereby increasing the comprehensive cold end temperature.

[0031] The outdoor air intake damper and indoor air intake damper are not simply fully open or fully closed, but can be adjusted continuously between 0-100%. This allows for more precise control of the secondary air temperature, thereby better maintaining the comprehensive cold end temperature within the preset range.

[0032] The secondary air heater uses the high-temperature auxiliary steam extracted from the thermal system of the thermal power plant to heat the secondary air to a higher temperature through a tubular heat exchanger, and then sends it to the air preheater. This can further increase the temperature of the secondary air, cooperate with the heat exchange of the air preheater, and finally achieve sufficient heating of the secondary air.

[0033] The above technical solution calculates the comprehensive cold end temperature of the air preheater by real-time monitoring of the secondary air temperature at the air preheater inlet and the flue gas temperature at the outlet, and automatically adjusts the opening of the outdoor air intake damper and the indoor air intake damper when the comprehensive cold end temperature exceeds the preset range, so as to accurately control the comprehensive cold end temperature to remain within the optimal range. At the same time, the technical solution adopts a continuously adjustable electric damper, which can more accurately control the secondary air temperature compared to the manual switch air intake damper. The above technical solution can effectively avoid the problem of the comprehensive cold end temperature of the air preheater being too high or too low due to changes in ambient temperature and unit load, thereby preventing the air preheater from low-temperature corrosion, blockage of heat storage elements and other problems, and improving the thermal efficiency and economy of the boiler.

[0034] In one embodiment, step 110 may include: obtaining the secondary air temperature from a first temperature sensor at the air preheater inlet, there are at least three first temperature sensors, and the secondary air temperature is the middle value of the temperatures measured by all the first temperature sensors; obtaining the flue gas temperature from a second temperature sensor at the air preheater outlet, there are at least three second temperature sensors, and the flue gas temperature is the middle value of the temperatures measured by all the second temperature sensors.

[0035] Here, the first temperature sensor is installed at the entrance of the secondary air duct of the air preheater to measure the temperature of the secondary air entering the air preheater. The second temperature sensor is installed at the outlet of the flue gas channel of the air preheater to measure the flue gas temperature at the outlet of the air preheater. The middle value of the secondary air temperature at the inlet of the air preheater is measured by the first temperature sensor. The middle value of the flue gas temperature at the outlet of the air preheater is measured by the second temperature sensor. The comprehensive cold end temperature of the air preheater can be obtained by adding these two average temperatures.

[0036] At least three first temperature sensors and second temperature sensors are respectively provided, and the secondary air temperature and the flue gas temperature are measured by taking the middle value, which can improve the accuracy and reliability of the measurement and provide a reliable basis for the subsequent precise control of the comprehensive cold end temperature.

[0037] In one embodiment, step 130 may include: adjusting the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle, and maintaining the sum of the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle at a first preset opening.

[0038] Here, the first preset opening can be an opening of 100%. The sum of the openings of the outdoor air intake damper and the indoor air intake damper is kept at a fixed first preset opening, and the total air intake volume can remain unchanged while adjusting the opening ratio of the two dampers. If the sum of the openings of the two dampers is not kept at a fixed value, the total air intake volume will change, thereby affecting the heat exchange effect of the air preheater.

[0039] By keeping the total air intake unchanged, it can be ensured that the heat exchange performance of the air preheater will not fluctuate due to changes in the air intake. This can better control the comprehensive cold end temperature of the air preheater and avoid temperature fluctuations caused by changes in the air intake. At the same time, it also avoids boiler load fluctuations caused by changes in the air intake, improving the stable operation of the unit.

[0040] In one embodiment, step 130 may include: when the comprehensive cold end temperature is greater than the upper limit of the preset range, increasing the opening of the outdoor air intake baffle and reducing the opening of the indoor air intake baffle; when the comprehensive cold end temperature is less than the lower limit of the preset range, reducing the opening of the outdoor air intake baffle and increasing the opening of the indoor air intake baffle.

[0041] Here, the preset range may be 148±2 degrees Celsius. The upper limit of the preset range may be 150 degrees Celsius, and the lower limit of the preset range may be 146 degrees Celsius.

[0042] Reducing the opening of the outdoor air intake damper means reducing the amount of cold air sucked in from the outside. Increasing the opening of the outdoor air intake damper means increasing the amount of cold air sucked in from the outside. Reducing the opening of the indoor air intake damper means reducing the amount of hot air sucked in from the top of the boiler. Increasing the opening of the indoor air intake damper means increasing the amount of hot air sucked in from the top of the boiler.

[0043] When the comprehensive cold end temperature is greater than the upper limit of the preset range, increase the outdoor air intake and reduce the indoor air intake, which can reduce the secondary air temperature and thus reduce the comprehensive cold end temperature. When the comprehensive cold end temperature is less than the lower limit of the preset range, reduce the outdoor air intake and increase the indoor air intake, which can increase the secondary air temperature and thus increase the comprehensive cold end temperature.

[0044] By finely adjusting the opening of the two outdoor and indoor air intake dampers, the comprehensive cold end temperature can be effectively controlled and maintained within a preset reasonable range. This can prevent the comprehensive cold end temperature from being too high or too low, thereby improving the heat exchange efficiency and service life of the air preheater, and reducing the boiler exhaust temperature and improving the boiler efficiency.

[0045] In one embodiment, the control method may further include: controlling the air supply fan to start when the sum of the opening of the indoor air intake damper and the opening of the indoor air intake damper is greater than a second preset opening.

[0046] Here, the second preset opening can be an opening of 95%. When the sum of the openings of the indoor air intake damper and the outdoor air intake damper reaches the fixed second preset opening, the blower can be started. The function of the blower is to mix and pressurize the air sucked in from indoor and outdoor, then heat it through the secondary air heater, further heat it in the air preheater, and finally send it to the boiler.

[0047] It should be understood that, when the blower meets other conditions for starting, if the sum of the opening of the indoor air intake damper and the opening of the indoor air intake damper is greater than the second preset opening, the blower can be controlled to start. Other conditions for starting the above blower include but are not limited to: 1) two air preheaters are running; 2) the corresponding side induced draft fan is running; 3) the outlet door of the blower on the other side is open; 4) the inlet door of the blower on the other side is open; 5) the opening of the blower blades on the other side is greater than 5%; 6) the opening of 10 secondary air dampers is greater than 15%; 7) the opening of the blower blades is less than 5%; 8) the outlet door of the blower is closed; 9) at least one inlet damper of the blower is open; 10) the temperature of the blower body allows; 11) the oil level of the lubricating oil tank ≮ minimum value; 12) the control oil pressure P>2.5MPa; 13) the lubricating oil flow L>3L / min.

[0048] When the sum of the openings of the indoor air intake damper and the outdoor air intake damper reaches the larger second preset opening, the blower is started to ensure that the blower has sufficient air intake, thereby avoiding the impact of insufficient air intake on the supply of secondary air. If the sum of the openings of the two dampers is less than the second preset opening, it means that the air intake may be insufficient. At this time, the blower should not be started to avoid the occurrence of blower surge accidents.

[0049] In one embodiment, the control method may further include: when the deviation between the actual value of the opening of any one of the indoor air intake baffle and the outdoor air intake baffle and the command value is greater than a preset value, ending the control.

[0050] Here, the indoor air intake damper and the outdoor air intake damper are equipped with an opening feedback signal for real-time monitoring of their actual opening values. The actual opening value is compared with the control command to calculate the deviation of the opening. The preset value can be set to 10%, that is, if the deviation between the actual opening and the command opening of any damper exceeds 10%, it is determined that the automatic adjustment of the damper has an abnormality, such as damper jamming, control circuit failure, etc. In order to prevent the other air intake damper from closing, resulting in interruption of the air intake of the blower, it is necessary to automatically exit the automatic state of the two air intake dampers and stop the automatic adjustment of the air intake temperature of the blower.

[0051] Based on the same concept, the present application also provides a controller for the comprehensive cold end temperature of an air preheater. Figure 2 is a block diagram of a controller 200 for integrated cold end temperature of an air preheater according to an exemplary embodiment. Figure 2 As shown, the controller 200 for the integrated cold end temperature of the air preheater includes the following modules: The temperature acquisition module 210 is used to acquire the secondary air temperature at the inlet of the air preheater and the flue gas temperature at the outlet of the air preheater; A cold end temperature determination module 220, for determining a comprehensive cold end temperature of the air preheater according to the sum of the secondary air temperature and the flue gas temperature; The damper opening adjustment module 230 is used to adjust the opening of the outdoor air intake damper and the opening of the indoor air intake damper when the comprehensive cold end temperature exceeds the preset range, so as to adjust the secondary air temperature and control the comprehensive cold end temperature to remain within the preset range. The opening of the outdoor air intake damper and the indoor air intake damper can be continuously and arbitrarily adjusted between the fully closed opening and the fully open opening. The indoor air intake damper is used to transport the hot air from the top of the boiler to the inlet of the air supply fan, and the outdoor air intake damper is used to transport the cold air outside the boiler room to the inlet of the air supply fan. The air supply fan is used to mix the hot air and the cold air and transport the mixed air to the air preheater through the secondary air heater.

[0052] Optionally, the temperature acquisition module 210 is specifically used to: acquire the secondary air temperature from a first temperature sensor at the air preheater inlet, there are at least three first temperature sensors, and the secondary air temperature is the middle value of the temperatures measured by all the first temperature sensors; acquire the flue gas temperature from a second temperature sensor at the air preheater outlet, there are at least three second temperature sensors, and the flue gas temperature is the middle value of the temperatures measured by all the second temperature sensors.

[0053] Optionally, the baffle opening adjustment module 230 is specifically used to: adjust the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle, and keep the sum of the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle at a first preset opening.

[0054] Optionally, the baffle opening adjustment module 230 is specifically used to: when the comprehensive cold end temperature is greater than the upper limit of the preset range, increase the opening of the outdoor air intake baffle and reduce the opening of the indoor air intake baffle; when the comprehensive cold end temperature is less than the lower limit of the preset range, reduce the opening of the outdoor air intake baffle and increase the opening of the indoor air intake baffle.

[0055] Optionally, the controller 200 further includes a blower start module, which is used to control the blower to start when the sum of the opening of the indoor air intake damper and the opening of the indoor air intake damper is greater than a second preset opening.

[0056] Optionally, the controller 200 further includes a baffle abnormal termination module, which is used to terminate the control when the deviation between the actual value of the opening of any one of the indoor air intake baffle and the outdoor air intake baffle and the command value is greater than a preset value.

[0057] The present application also provides a control system for the comprehensive cold end temperature of an air preheater. Figure 3 is a structural diagram of a control system 300 for the integrated cold end temperature of an air preheater according to an exemplary embodiment. Figure 3 As shown, the control system 300 of the air preheater integrated cold end temperature includes: An outdoor air intake baffle 310, an indoor air intake baffle 320, a boiler 330, a secondary air heater 340, an air preheater 350 and a controller 200, wherein the secondary air heater 340 is coupled to the outdoor air intake baffle 310 and the indoor air intake baffle 320, the secondary air heater 340 is connected to the air preheater 350, the air preheater 350 is connected to the boiler 330, and the controller 200 is connected to the outdoor air intake baffle 310 and the indoor air intake baffle 320; The outdoor air intake baffle 310 is used to transport the hot air from the top of the boiler 330 to the secondary air heater 340; The outdoor air intake baffle 310 is used to transport the cold air outside the boiler 330 room to the secondary air heater 340; The secondary air heater 340 is used to heat the hot air and the cold air and transmit them to the air preheater 350; The controller 200 is used to execute the steps of the control method provided in the first aspect of the present application.

[0058] The control system 300 may include a plurality of air preheaters 350, and an outdoor air intake damper 310, an indoor air intake damper 320, and a secondary air heater corresponding to each air preheater 350. The plurality of air preheaters 350 are connected to a boiler 330 and a controller 200. The controller 200 executes the above control method and controls the outdoor air intake dampers 310 and the indoor air intake dampers 320 corresponding to the plurality of air preheaters 350 at the same time.

[0059] Optionally, the control system 300 includes: A first temperature sensor 370 is provided at the inlet of the air preheater 350 , and the controller 200 is connected to the first temperature sensor 370 .

[0060] The control system 300 may include a plurality of air preheaters 350 , and a first temperature sensor 370 corresponding to each air preheater 350 .

[0061] Optionally, the control system 300 includes: A second temperature sensor 380 is provided at the outlet of the air preheater 350 , and the controller 200 is connected to the second temperature sensor 380 .

[0062] The control system 300 may include a plurality of air preheaters 350 , and a second temperature sensor 380 corresponding to each air preheater 350 .

[0063] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0064] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0065] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for controlling the comprehensive cold end temperature of an air preheater, characterized in that: include: Acquire the secondary air temperature at the inlet of the air preheater, and acquire the flue gas temperature at the outlet of the air preheater; Determining the comprehensive cold end temperature of the air preheater according to the sum of the secondary air temperature and the flue gas temperature; When the comprehensive cold end temperature exceeds the preset range, the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle are adjusted to adjust the secondary air temperature and control the comprehensive cold end temperature to remain within the preset range. The opening of the outdoor air intake baffle and the indoor air intake baffle can be continuously and arbitrarily adjusted between the fully closed opening and the fully open opening. The indoor air intake baffle is used to transport the hot air from the top of the boiler to the inlet of the air supply fan, and the outdoor air intake baffle is used to transport the cold air outside the boiler room to the inlet of the air supply fan. The air supply fan is used to mix the hot air and the cold air and transport the mixed air to the air preheater through the secondary air heater.

2. The control method according to claim 1, characterized in that: The obtaining of the secondary air temperature at the inlet of the air preheater and the obtaining of the flue gas temperature at the outlet of the air preheater include: The secondary air temperature is obtained from the first temperature sensors at the air preheater inlet, there are at least three first temperature sensors, and the secondary air temperature is the middle value of the temperatures measured by all the first temperature sensors; The flue gas temperature is obtained from a second temperature sensor at an air preheater outlet, there are at least three second temperature sensors, and the flue gas temperature is the middle value of the temperatures measured by all the second temperature sensors.

3. The control method according to claim 1, characterized in that: When the comprehensive cold end temperature exceeds a preset range, adjusting the opening of the outdoor air intake damper and the opening of the indoor air intake damper includes: The opening of the outdoor air intake baffle and the opening of the indoor air intake baffle are adjusted, and the sum of the opening of the outdoor air intake baffle and the opening of the indoor air intake baffle is maintained at a first preset opening.

4. The control method according to claim 3, characterized in that: When the comprehensive cold end temperature exceeds a preset range, adjusting the opening of the outdoor air intake damper and the opening of the indoor air intake damper includes: When the comprehensive cold end temperature is greater than the upper limit of the preset range, increasing the opening of the outdoor air intake damper and decreasing the opening of the indoor air intake damper; When the comprehensive cold-end temperature is less than the lower limit of the preset range, the opening of the outdoor air intake damper is reduced, and the opening of the indoor air intake damper is increased.

5. The control method according to any one of claims 1 to 4, characterized in that: The method further comprises: When the sum of the opening of the indoor air intake damper and the opening of the indoor air intake damper is greater than the second preset opening, the air supply fan is controlled to start.

6. The control method according to any one of claims 1 to 4, characterized in that: The method further comprises: When the deviation between the actual value of the opening degree of any one of the indoor air intake damper and the outdoor air intake damper and the command value is greater than a preset value, the control is terminated.

7. A controller for the comprehensive cold end temperature of an air preheater, characterized in that: The controller is used to execute the method according to any one of claims 1 to 6.

8. A control system for the integrated cold end temperature of an air preheater, characterized in that: include: An outdoor air intake baffle, an indoor air intake baffle, a blower, a boiler, a secondary air heater, an air preheater, and a controller, wherein the secondary air heater is coupled to the outdoor air intake baffle and the indoor air intake baffle, the secondary air heater is connected to the air preheater, the air preheater is connected to the boiler, and the controller is connected to the outdoor air intake baffle and the indoor air intake baffle; The outdoor air intake baffle is used to transport the hot air from the top of the boiler to the inlet of the blower; The outdoor air intake baffle is used to transport the cold air outside the boiler room to the inlet of the air blower; The blower is used to mix the hot air and the cold air and deliver the mixed air to the air preheater through the secondary air heater; The controller is used to execute the method according to any one of claims 1 to 7.

9. The control system according to claim 8, characterized in that: include: A first temperature sensor is provided at the inlet of the air preheater, and the controller is connected to the first temperature sensor.

10. The control system according to claim 9, characterized in that: include: A second temperature sensor is provided at the outlet of the air preheater, and the controller is connected to the second temperature sensor.

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