Ultra-low load dry operation control method and device for unit

Abstract

The application relates to the technical field of thermal power generation, in particular to a method and device for controlling dry operation of a unit at ultra-low load, wherein the method comprises the following steps: based on wall temperature data of a water-cooled wall of a target unit and flue gas temperature distribution data of a cross-section of a furnace at a folded angle, an actual horizontal position and an actual relative height of a flame center in the furnace are calculated; when a position deviation between the actual horizontal position and a theoretical horizontal position is greater than a preset position deviation threshold or a height deviation between the actual relative height and a theoretical relative height is greater than a preset height deviation threshold, an actual combustion center of the furnace is determined based on the actual horizontal position and the actual relative height, a hot load deviation adjustment action is generated and controlled for the target unit furnace to execute until the dry operation requirement of the target unit at the ultra-low load is met. The application can guarantee stable combustion and hydrodynamic safety of the unit at the ultra-low load, solve the denitration problem at a wide load, reduce energy consumption at a low load, and improve the safety and economy of rapid peak shaving of the unit.

Description

Technical Field

[0001] This application relates to the field of thermal power generation technology, and in particular to a method and device for controlling ultra-low load dry-state operation of a generating unit. Background Technology

[0002] Ultracritical (supercritical) coal-fired power units have become the main type of coal-fired power generation due to their advantages of high efficiency and low emissions. With the development of time and the large-scale grid connection of new energy sources, long-term continuous operation at low load has become the normal operating condition for these units. However, under low load conditions, these units generally face technical bottlenecks such as frequent dry-wet state transitions and difficulties in controlling feedwater flow.

[0003] In related technologies, the rapid peak-shaving strategy for supercritical units focuses on improving the load regulation rate. This is usually achieved by adjusting the coal-water ratio to control the superheat at the intermediate point and matching the load pressure according to the sliding pressure curve to achieve steady-state dry operation. If the load drops to the lower limit of dry operation (usually 30%~40%), the unit will be forced to switch to wet operation. At this time, the separator water level control loop will generally be activated to maintain stable water circulation.

[0004] However, in related technologies, these conventional measures have a lag in response at ultra-low loads (below 30%), are prone to overshoot in feedwater control, have poor stability in dry operation, and are frequently switched between dry and wet states. Moreover, during low-load dry operation, the combustion stability in the furnace is poor, energy consumption increases significantly, and the flue gas temperature also decreases, resulting in insufficient inlet flue gas temperature of the denitrification system, which cannot meet the activity requirements of the denitrification catalyst, causing excessive nitrogen oxide emissions. It is difficult to achieve wide-load denitrification, has poor adaptability in practical applications, seriously affects the safety and economy of the unit, and cannot meet the strict requirements of coal-fired power indicators for deep peak shaving of coal-fired units, which urgently needs to be solved. Summary of the Invention

[0005] This application provides a method and apparatus for controlling ultra-low load dry operation of a power unit, in order to solve the problems in related technologies, such as delayed response at ultra-low load, easy overshoot of feedwater control, poor stability of dry operation, poor furnace combustion stability, significantly increased energy consumption, and decreased flue gas temperature during low load dry operation, which cannot meet the activity requirements of denitrification catalysts, making it difficult to achieve wide load denitrification, poor adaptability in practical applications, seriously affecting the safety and economy of the unit, and failing to meet the strict requirements of coal-fired power indicators for deep peak shaving of coal-fired units.

[0006] The first aspect of this application provides a method for controlling ultra-low load dry-state operation of a power unit, comprising the following steps: calculating the actual horizontal position and actual relative height of the flame center in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace; determining the actual combustion center of the furnace based on the actual horizontal position and the actual relative height when the position deviation between the actual horizontal position and the theoretical horizontal position is greater than a preset position deviation threshold or the height deviation between the actual relative height and the theoretical relative height is greater than a preset height deviation threshold; and generating a heat load deviation adjustment action for the furnace based on the actual combustion center, thereby controlling the target unit to execute the heat load deviation adjustment action until the actual operating state of the target unit meets the ultra-low load dry-state operation requirements of the target unit.

[0007] Optionally, in one embodiment of this application, calculating the actual horizontal position and actual relative height of the flame center in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section includes: determining the wall temperature distribution of the water-cooled wall based on the wall temperature data; calculating the temperature field of the furnace based on the flue gas temperature distribution data of the flame deflector section; calculating the actual heat load in the furnace based on the wall temperature distribution and the temperature field; calculating the actual horizontal position of the flame in the furnace based on the actual heat load; and calculating the average temperature of the flame deflector section of the furnace based on the flue gas temperature distribution data of the flame deflector section; and determining the actual relative height of the flame based on the average temperature of the flame deflector section.

[0008] Optionally, in one embodiment of this application, before calculating the actual horizontal position and the actual relative height of the flame in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace, the method further includes: constructing a first model to characterize the relationship between the furnace heat load and the horizontal position of the flame center based on multiple sets of wall temperature distribution data, furnace temperature field data, furnace heat load data, and flame center horizontal position data of the target unit under the target combustion state; constructing a second model to characterize the relationship between the furnace heat load and the wall temperature distribution and the furnace temperature field; and constructing a third model to characterize the relationship between the average temperature of the flame deflector section and the relative height of the flame center; and determining the calculation model for the actual horizontal position and the actual relative height based on the first model, the second model, and the third model.

[0009] Optionally, in one embodiment of this application, the method further includes: detecting the over-temperature risk of the water-cooled wall based on the wall temperature data of the water-cooled wall and a preset over-temperature risk condition; and when an over-temperature risk is detected in the water-cooled wall, obtaining the first-stage extraction steam pressure and the second-stage extraction steam pressure of the target unit; calculating the first-stage steam flow deviation corresponding to the first-stage extraction steam pressure based on the first-stage extraction steam pressure, and calculating the second-stage steam flow deviation corresponding to the second-stage extraction steam pressure based on the second-stage extraction steam pressure; generating the feedwater flow deviation of the target unit based on the average value of the first-stage steam flow deviation and the second-stage steam flow deviation, so as to generate the feedwater flow adjustment action of the target unit based on the feedwater flow deviation; and controlling the target unit to execute the heat load deviation adjustment action and the feedwater flow adjustment action until the actual state of the target unit meets the ultra-low load dry-state operation requirements of the target unit.

[0010] Optionally, in one embodiment of this application, the method further includes: when an overheating risk is detected in the water-cooled wall, generating a first auxiliary control action of the target unit based on the steam extraction rate of the target unit, or generating a second auxiliary control action of the target unit based on the valve status of the target heater in the target unit; controlling the target unit to perform the heat load deviation adjustment action, the feedwater flow rate regulation action, and at least one of the first auxiliary control action and the second auxiliary control action, until the actual state of the target unit meets the ultra-low load dry-state operation requirements of the target unit.

[0011] A second aspect of this application provides an ultra-low load dry-state operation control device for a generator unit, comprising: a first calculation module, configured to calculate the actual horizontal position and actual relative height of the flame center in the furnace based on the wall temperature data of the water-cooled wall of the target generator unit and the flue gas temperature distribution data of the flame deflection section of the furnace; a first determination module, configured to determine the actual combustion center of the furnace based on the actual horizontal position and actual relative height when the position deviation between the actual horizontal position and the theoretical horizontal position is greater than a preset position deviation threshold or the height deviation between the actual relative height and the theoretical relative height is greater than a preset height deviation threshold; and a first control module, configured to generate a heat load deviation adjustment action of the furnace based on the actual combustion center, so as to control the target generator unit to perform the heat load deviation adjustment action until the actual operating state of the target generator unit meets the ultra-low load dry-state operation requirements of the target generator unit.

[0012] Optionally, in one embodiment of this application, the first calculation module includes: a first calculation unit, configured to determine the wall temperature distribution of the water-cooled wall based on the wall temperature data, calculate the temperature field of the furnace based on the flue gas temperature distribution data of the flame deflector section, calculate the actual heat load in the furnace based on the wall temperature distribution and the temperature field, and calculate the actual horizontal position of the flame in the furnace based on the actual heat load; and a second calculation unit, configured to calculate the average temperature of the flame deflector section of the furnace based on the flue gas temperature distribution data of the flame deflector section, and determine the actual relative height of the flame based on the average temperature of the flame deflector section.

[0013] Optionally, in one embodiment of this application, it further includes: a construction module, configured to, before calculating the actual horizontal position and the actual relative height of the flame in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace, construct a first model to characterize the relationship between the furnace heat load and the horizontal position of the flame center, a second model to characterize the relationship between the furnace heat load and the wall temperature distribution and the furnace temperature field, and a third model to characterize the relationship between the average temperature of the flame deflector section and the relative height of the flame center, based on multiple sets of wall temperature distribution data, furnace temperature field data, furnace heat load data, and horizontal position data of the flame center of the target unit under the target combustion state; and a second determination module, configured to determine the calculation model of the actual horizontal position and the actual relative height based on the first model, the second model, and the third model.

[0014] Optionally, in one embodiment of this application, it further includes: a detection module, configured to detect the over-temperature risk of the water-cooled wall based on the wall temperature data of the water-cooled wall and a preset over-temperature risk condition, and to obtain the first-stage extraction steam pressure and the second-stage extraction steam pressure of the target unit when the over-temperature risk of the water-cooled wall is detected; a second calculation module, configured to calculate the first-stage steam flow deviation corresponding to the first-stage extraction steam pressure based on the first-stage extraction steam pressure, and to calculate the second-stage steam flow deviation corresponding to the second-stage extraction steam pressure based on the second-stage extraction steam pressure; a first generation module, configured to generate the feedwater flow deviation of the target unit based on the average value of the first-stage steam flow deviation and the second-stage steam flow deviation, so as to generate the feedwater flow adjustment action of the target unit based on the feedwater flow deviation; and a second control module, configured to control the target unit to execute the heat load deviation adjustment action and the feedwater flow adjustment action until the actual state of the target unit meets the ultra-low load dry-state operation requirements of the target unit.

[0015] Optionally, in one embodiment of this application, it further includes: a second generation module, configured to generate a first auxiliary control action of the target unit based on the steam extraction rate of the target unit, or generate a second auxiliary control action of the target unit based on the valve status of the target heater in the target unit when an overheating risk is detected in the water-cooled wall; and a third control module, configured to control the target unit to perform the heat load deviation adjustment action, the feedwater flow rate regulation action, and at least one of the first auxiliary control action and the second auxiliary control action, until the actual state of the target unit meets the ultra-low load dry-state operation requirements of the target unit.

[0016] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the ultra-low load dry-state operation control method for a unit as described in the above embodiments.

[0017] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described ultra-low load dry-state operation control method for a unit.

[0018] A fifth aspect of this application provides a computer program product, including a computer program that, when executed, is used to implement the above-described ultra-low load dry-state operation control method for a unit.

[0019] This application embodiment can ensure that the unit operates in dry state at more than 20% load through a water-cooled wall safety detection system and a heat load deviation correction strategy, avoiding the safety risks caused by frequent switching between dry and wet states and improving the unit's deep peak-shaving capability; by adding a heating system to increase the feedwater temperature, thereby increasing the inlet flue gas temperature of the denitrification system, meeting the denitrification catalyst activity requirements under low load conditions, achieving nitrogen oxide emissions in compliance with standards across the entire load range, and solving the problem of wide-load denitrification; by adding a heating system and working in conjunction with a pressure matcher, the steam-water circulation volume of the water-cooled wall is increased, ensuring hydrodynamic safety; at the same time, the economizer outlet water temperature is increased, reducing the heat absorption load of the water-cooled wall, which is conducive to stable combustion under low load and improving hydrodynamic safety and stable combustion capability; by extracting low-temperature superheater outlet steam for heating, the main steam temperature is increased, reducing energy loss under low load conditions and reducing unit coal consumption; by using the fixed relationship between extraction steam pressure and steam flow rate to dynamically correct the feedwater flow rate, precise feedwater control is achieved, avoiding feedwater overshoot during rapid load changes, preventing MFT triggered by low feedwater flow rate, and ensuring safe and stable unit operation. This solves the problems in related technologies, such as delayed response at ultra-low loads, easy overshooting of feedwater control, poor stability during dry operation, poor furnace combustion stability during low-load dry operation, significantly increased energy consumption, and decreased flue gas temperature, which cannot meet the activity requirements of denitrification catalysts, making it difficult to achieve wide-load denitrification, poor adaptability in practical applications, seriously affecting the safety and economy of the unit, and failing to meet the strict requirements of coal-fired power indicators for deep peak shaving of coal-fired units.

[0020] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a method for controlling ultra-low load dry-state operation of a generator unit according to an embodiment of this application; Figure 2 This is a schematic diagram of the furnace of a coal-fired boiler in an ultracritical (supercritical) unit according to an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a control device for ultra-low load dry-state operation of an ultra-supercritical unit according to an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a water-cooled wall safety monitoring system according to an embodiment of this application; Figure 5 This is a schematic diagram showing the arrangement of an infrared thermometer at the flame deflection angle height according to one embodiment of this application; Figure 6A flowchart illustrating the process of determining the flame center position according to an embodiment of this application; Figure 7 This is a schematic diagram of the structure of a newly added water supply heating system according to an embodiment of this application; Figure 8 This is a schematic diagram of the structure of a water supply coordination control system according to an embodiment of this application; Figure 9 This is a schematic diagram comparing the effects of water flow rate correction before and after one embodiment of this application; Figure 10 This is a schematic diagram of the structure of the ultra-low load dry-state operation control device for a unit provided according to an embodiment of this application; Figure 11 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application.

[0022] Figure label: 10 - Ultra-low load dry-state operation control device for the unit; 100 - First calculation module, 200 - First determination module and 300 - First control module; 1101 - Memory, 1102 - Processor and 1103 - Communication interface. Detailed Implementation

[0023] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0024] The following description, with reference to the accompanying drawings, describes a method and apparatus for controlling ultra-low load dry-state operation of a unit according to an embodiment of this application. Addressing the issues raised in the background art regarding the following problems: delayed response at ultra-low loads, easy overshoot in feedwater control, and poor stability during dry-state operation; poor furnace combustion stability, significantly increased energy consumption, and decreased flue gas temperature during low-load dry-state operation, which fails to meet the activity requirements of denitrification catalysts and hinders the achievement of wide-load denitrification. These issues result in poor adaptability in practical applications, severely impacting the safety and economy of the unit and failing to meet the stringent requirements of coal-fired power generation indicators for deep peak shaving. This application provides a method for controlling ultra-low load dry-state operation of a unit. In this method, a water-cooled wall safety detection system and a heat load deviation correction strategy can be used to ensure dry-state operation of the unit at more than 20% load, avoiding safety risks caused by frequent switching between dry and wet states and improving the unit's deep peak shaving capability. Furthermore, by adding a heating system... Increasing the feedwater temperature raises the inlet flue gas temperature of the denitrification system, meeting the catalyst activity requirements under low-load conditions, achieving compliant nitrogen oxide emissions across the entire load range, and solving the problem of wide-load denitrification. The addition of a heating system and the synergistic effect of a pressure matcher increase the steam-water circulation volume of the water-cooled walls, ensuring hydrodynamic safety. Simultaneously, increasing the economizer outlet water temperature reduces the heat absorption load of the water-cooled walls, facilitating stable combustion under low loads and improving hydrodynamic safety and combustion stability. Extracting steam from the low-temperature superheater outlet for heating increases the main steam temperature, reducing energy loss under low-load conditions and lowering unit coal consumption. Utilizing the fixed relationship between extraction steam pressure and steam flow rate to dynamically correct feedwater flow rate enables precise feedwater control, preventing feedwater overshoot during rapid load changes and preventing MFT (Main Fuel Turbine Default) triggered by low feedwater flow, thus ensuring safe and stable unit operation. This solves the problems in related technologies, such as delayed response at ultra-low loads, easy overshooting of feedwater control, poor stability during dry operation, poor furnace combustion stability during low-load dry operation, significantly increased energy consumption, and decreased flue gas temperature, which cannot meet the activity requirements of denitrification catalysts, making it difficult to achieve wide-load denitrification, poor adaptability in practical applications, seriously affecting the safety and economy of the unit, and failing to meet the strict requirements of coal-fired power indicators for deep peak shaving of coal-fired units.

[0025] Specifically, Figure 1 A flowchart of a method for controlling ultra-low load dry-state operation of a unit, provided in an embodiment of this application.

[0026] like Figure 1 As shown, the ultra-low load dry-state operation control method of this unit includes the following steps: Step S101: Based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace, calculate the actual horizontal position and actual relative height of the flame center in the furnace.

[0027] Step S102: When the positional deviation between the actual horizontal position and the theoretical horizontal position is greater than a preset positional deviation threshold or the height deviation between the actual relative height and the theoretical relative height is greater than a preset height deviation threshold, the actual combustion center of the furnace is determined based on the actual horizontal position and the actual relative height.

[0028] Step S103: Based on the actual combustion center, generate the furnace heat load deviation adjustment action to control the target unit to perform the heat load deviation adjustment action until the actual operating state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

[0029] Under low-load conditions, the steam-water circulation characteristics of ultracritical (supercritical) units change significantly, and the working fluid velocity within the water-cooled walls decreases, making them prone to uneven heat transfer and localized overheating, forcing the unit to switch from dry to wet operation. The dry-to-wet transition process not only has a long state transition time, affecting peak-shaving response speed, but also poses significant safety risks, potentially leading to failures such as water-cooled wall wear and vibration.

[0030] As one possible approach, this application can start from maintaining stable combustion of the unit under ultra-low load conditions to maintain stable dry-state operation of the unit under ultra-low load conditions.

[0031] For example, this application may first obtain the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace.

[0032] Here, the target unit can be understood as a specific ultra-supercritical unit undergoing dry-state stable operation control under ultra-low load conditions, hereinafter referred to as the unit. The furnace here refers to the combustion chamber of the coal-fired boiler within the unit, that is, the space enclosed by water-cooled walls where fuel (pulverized coal) burns and releases heat, such as... Figure 2 As shown, Figure 2 This is a schematic diagram of the furnace of a coal-fired boiler in an ultracritical (supercritical) unit according to an embodiment of this application.

[0033] Figure 3 This application describes an embodiment of a control device for ultra-low load dry-state operation of an ultra-supercritical unit. For example... Figure 3 As shown, embodiments of this application may, but are not limited to, use a water-cooled wall safety detection system to monitor the temperature distribution of the water-cooled wall of the target unit; and use a furnace temperature field monitoring system located in the lower region of the boiler flame deflector to collect flue gas temperature distribution data of the furnace flame deflector section.

[0034] Figure 4 This is a schematic diagram of the structure of a water-cooled wall safety monitoring system according to an embodiment of this application. Figure 4As shown, the water-cooled wall safety detection system in this application embodiment includes, but is not limited to, temperature measuring points uniformly arranged circumferentially along the outlet of the vertical water-cooled wall of the boiler, and temperature measuring points spaced longitudinally along a portion of the vertical water-cooled wall. The circumferential and longitudinal measuring points form a three-dimensional temperature network, thereby enabling real-time acquisition of the boiler's water-cooled wall temperature data and simulating the heat load field of the vertical water-cooled wall region.

[0035] Figure 5 This is a schematic diagram showing the arrangement of an infrared thermometer at the flame deflection angle height according to one embodiment of this application. Figure 5 As shown, the furnace temperature field monitoring system in this embodiment can employ one or more infrared thermometers arranged at the height of the flame deflection angle in the furnace. The flue gas temperature distribution data at the flame deflection angle section of the furnace can be obtained through infrared detection technology. The heat load distribution data inside the furnace can be calculated from the flue gas temperature distribution data at the flame deflection angle section, thereby preparing data for the subsequent furnace-side heat load deviation.

[0036] Based on the wall temperature data of the water-cooled wall and the flue gas temperature distribution data of the flame deflector section of the furnace, the embodiments of this application can calculate the actual horizontal position and actual relative height of the flame center in the furnace.

[0037] Here, the actual horizontal position of the flame center can be understood as the projected position of the flame center on the horizontal cross-section of the furnace (the cross-section of the flame deflector parallel to the furnace). The actual relative height can be understood as the relative height of the flame center in the vertical direction relative to the bottom of the furnace (the cross-section of the furnace inlet or the inflection point of the cold ash hopper), that is, the relative proportion of the flame center to the total height of the furnace (for example, at 0.65, that is, about two-thirds of the height).

[0038] When the height deviation between the actual relative height and the theoretical relative height is greater than the preset height deviation, the actual combustion center of the furnace is determined based on the actual horizontal position and the actual relative height.

[0039] Based on the actual horizontal position of the flame center, this application embodiment can calculate the positional deviation between the actual horizontal position and the theoretical horizontal position (in this application embodiment, the distance in the x-direction and the distance in the y-direction between the actual horizontal position and the theoretical horizontal position can be used as the positional deviation evaluation standard, and the larger the distance, the larger the deviation), thereby determining whether the flame center is skewed, for example, relative to the theoretical horizontal position, the actual horizontal position is forward, backward, left, right, etc.

[0040] If the positional deviation between the two exceeds a preset positional deviation threshold, the flame center is determined to be too skewed and requires adjustment. Here, the theoretical horizontal position can be understood as the projected position of the flame center on the horizontal cross-section of the furnace (parallel to the flame deflection angle cross-section) under design conditions or optimal combustion. The preset positional deviation threshold can be understood as the upper limit of the preset positional deviation between the actual horizontal position and the theoretical horizontal position; exceeding this limit indicates that the flame center is too skewed and requires adjustment.

[0041] Correspondingly, based on the actual relative height of the flame center, the embodiments of this application can calculate the positional deviation between the actual relative height and the theoretical relative height, thereby determining whether the flame center is too high or too low.

[0042] If the height deviation between the two exceeds the preset height deviation threshold, the flame center is determined to be too high or too low, and adjustment is required. Here, the theoretical relative height can be understood as the relative height of the flame center in the vertical direction relative to the bottom of the furnace (furnace inlet section or cold ash hopper inflection point) under ideal combustion conditions. The preset height deviation threshold can be understood as the upper limit of the height deviation between the preset actual relative height and the theoretical relative height. Exceeding this upper limit indicates that the flame center is too high or too low, and adjustment is also necessary.

[0043] When adjustments are required, embodiments of this application can determine the actual combustion center of the furnace (i.e., the flame center, (x, y, z)) based on the actual horizontal position (x, y) and the actual relative height z of the flame center. Based on this actual combustion center, a furnace heat load deviation adjustment action is generated to control the target unit to perform the heat load deviation adjustment action until the actual operating state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

[0044] Here, the heat load deviation adjustment action can be understood as the adjustment action determined based on the actual combustion center of the furnace to correct the furnace side heat load deviation, so that the furnace combustion state reaches the ideal combustion state. That is, by adjusting the secondary air ratio of each layer, the opening and tilt angle of the burnout air (SOFA), the coal feed rate / coal mill combination of each layer, the fineness of coal powder, the primary air velocity, the oxygen content, the total air volume, etc., to obtain the desired furnace combustion state.

[0045] For example, adjusting the burner tilt angle, the ratio of secondary air between the upper and lower layers, and the burnout air opening can bring the relative flame height back to the optimal range.

[0046] When the flame center deviates from the horizontal cross-section of the furnace (e.g., towards the left, right, front, or rear wall), the horizontal direction of the nozzle is changed by adjusting the left and right swing angle of the burner to guide the flame center back to the center; the amount of pulverized coal fed to each layer of burners or the combination of coal mills is adjusted to reduce the amount of pulverized coal fed to the deviated side and increase the amount of pulverized coal fed to the opposite side; the horizontal air volume distribution in the horizontal direction is changed by adjusting the horizontal distribution of burnout air to correct the heat load deviation; and the horizontal deviance of the flame is corrected by adjusting the horizontal distribution of secondary air to change the opening of the secondary air dampers on the left and right sides.

[0047] Finally, the target unit is controlled to perform the generated heat load deviation adjustment action until the actual operating state of the target unit meets the ultra-low load dry-state operation requirements. Here, the ultra-low load dry-state operation requirements can be understood as the dry-state stable operation state that the target unit can achieve under ultra-low load after adjustment.

[0048] It should be noted that the specific preset position deviation threshold, preset height deviation threshold, and adjustment range can all be set and adjusted by those skilled in the art according to the actual situation. The embodiments in this application are only illustrative and do not impose any specific limitations.

[0049] The embodiments of this application can obtain the furnace side heat load distribution through the furnace temperature field monitoring system, and combine the water-cooled wall temperature distribution data and the flue gas temperature distribution data of the furnace flame deflector section to comprehensively judge the location and degree of heat load deviation. By adjusting the burner swing angle, pulverized coal feed rate or desuperheating water flow rate, the furnace side heat load deviation can be corrected to ensure the uniformity of furnace combustion.

[0050] Optionally, in one embodiment of this application, before calculating the actual horizontal position and actual relative height of the flame in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace, the method further includes: constructing a first model to characterize the relationship between the furnace heat load and the horizontal position of the flame center based on the wall temperature distribution data, furnace temperature field data, furnace heat load data, and horizontal position data of the flame center of multiple target units under the target combustion state; constructing a second model to characterize the relationship between the furnace heat load and the wall temperature distribution and the furnace temperature field; and constructing a third model to characterize the relationship between the average temperature of the flame deflector section and the relative height of the flame center; and determining the calculation model for the actual horizontal position and actual relative height based on the first model, the second model, and the third model.

[0051] As one possible approach, this application can first determine the calculation model for the actual horizontal position and actual relative height of the flame center.

[0052] For example, this application may, but is not limited to, construct three models and combine them for calculation based on wall temperature distribution data, furnace temperature field data, furnace heat load data, and flame horizontal position data of multiple target units under target combustion conditions: (1) A first model used to characterize the relationship between furnace heat load and the horizontal position of the flame center; (2) A second model used to characterize the relationship between furnace heat load, wall temperature distribution, and furnace temperature field; (3) A third model used to characterize the relationship between the average temperature of the flame deflector section and the relative height of the flame center.

[0053] In summary, the embodiments of this application can preliminarily construct a model of the correspondence between the boiler furnace heat load and the horizontal position of the flame center, a model of the correspondence between the furnace heat load and the vertical water-cooled wall temperature and the furnace temperature field, and a model of the correspondence between the average temperature of the flame deflector section and the relative height position of the flame center, based on boiler thermal calculations and combined with the actual coal quality fed into the boiler.

[0054] Then, in this embodiment of the application, after adjusting the boiler's combustion state to the target combustion state, multiple sets of data can be recorded, including boiler furnace heat load, horizontal position of the flame center, flame deflection angle height, temperature field of the horizontal section of the furnace, and vertical water-cooled wall temperature distribution under different operating conditions. Here, the target combustion state can be understood as the ideal combustion state of the boiler.

[0055] Finally, the embodiments of this application can optimize the initially constructed model based on the measured data after adjusting the combustion state of the boiler to the optimal state, and obtain the final prediction model of the furnace heat load and the horizontal position of the flame center (i.e., the first model in the embodiments of this application), the calculation model of the furnace heat load, the vertical water-cooled wall temperature, and the furnace temperature field (i.e., the second model in the embodiments of this application), and the prediction model of the average temperature of the flame deflector section and the relative height position of the flame center (i.e., the third model in the embodiments of this application).

[0056] Specifically, Figure 6 This is a flowchart illustrating the process of determining the flame center position (horizontal position + relative height) according to an embodiment of this application. Figure 6 As shown, the construction process of the first model, the second model, and the third model can be represented, but is not limited to, as follows: (1) First, in the embodiments of this application, boiler thermal calculation (such as thermal calculation, furnace heat exchange calculation, radiation heat exchange formula, etc.) can be used to theoretically calculate the theoretical height / position of the flame center under different heat loads based on the designed coal type, furnace structure, and heat transfer surface arrangement. Then, the actual coal quality (industrial analysis, elemental analysis, calorific value, ash melting point) is substituted into the thermal calculation to correct the theoretical flame center.

[0057] Then, in the embodiments of this application, a set of theoretical curves / functions / table models can be formed with the furnace heat load q (or cross-sectional heat load, volumetric heat load) as the independent variable and the theoretical height / position of the flame center as the dependent variable. Among them, the furnace radiative heat transfer, the flue gas temperature distribution along the path, and the heat absorption of the water-cooled wall can all be calculated through a thermodynamic calculation process.

[0058] Next, in this embodiment of the application, a theoretical correspondence can be established using the heat transfer path of heat load → flue gas temperature field → water-cooled wall heat flux density → wall temperature; and combined with the actual coal quality, the flame filling degree and the flue gas temperature against the wall are corrected to obtain the initial correspondence model of heat load-wall temperature and heat load-temperature field.

[0059] Furthermore, based on the horizontal cross-sectional distribution of smoke temperature at different flame heights given by thermal calculations at the flame deflection angle positions, the embodiments of this application can establish an initial theoretical correspondence model with the relative flame height as the independent variable and the average cross-sectional temperature as the dependent variable.

[0060] In simple terms, the embodiments of this application can first establish a theoretical model by using boiler thermal calculation and design coal quality, and then correct it with actual coal quality parameters fed into the furnace to obtain an initial correspondence model.

[0061] (2) In this embodiment of the application, the unit can be adjusted to the optimal state through combustion adjustment, and initial data such as boiler furnace heat load, flame center position (horizontal position + relative height), flame deflection angle height, furnace horizontal section temperature field, and vertical water-cooled wall temperature distribution can be obtained. The actual mathematical expressions of each initial correspondence model can be established by using regression analysis (linear, polynomial, exponential, etc.) or machine learning. For example: relative height of flame center = a × furnace heat load² + b × furnace heat load + c.

[0062] Alternatively, a simplified segmented energy balance equation can be established first, and then the empirical coefficients in the equation can be calibrated using measured temperature field data (such as those obtained through acoustic or infrared thermometry). In other words, based on the initial measured data, the "correspondence model" is upgraded to a predictive model that can be calculated online through regression / fitting.

[0063] (3) Based on the established correspondence or model, the embodiments of this application can reflect the relative horizontal position of the flame center in the horizontal section of the furnace by the wall temperature deviation between the four vertical water-cooled walls, and reflect the relative height position of the flame center in the furnace by the average temperature of the flame deflector section (the higher the relative height of the flame center in the furnace, the higher the average temperature of the flame deflector section). Thus, the embodiments of this application can effectively determine whether there are problems such as flame uneven burning and the flame condition in the furnace, turning the invisible "combustion morphology inside the furnace" into a quantifiable, monitorable, and adjustable operating indicator.

[0064] (4) The deviation of the combustion center (flame center) in terms of horizontal position and relative height, which is comprehensively reflected by the horizontal position and relative height of the flame center, is used to guide the adjustment of air, pulverized coal, and angle, so as to achieve temperature control, prevention of overheating, prevention of coking, and control of NOx. Based on the monitoring of the furnace flame condition, the desired furnace combustion state is obtained by adjusting the secondary air ratio of each layer, the opening degree of burnout air (SOFA), the inclination angle, the pulverized coal feed rate / coal mill combination of each layer, the fineness of pulverized coal, the primary air velocity, the oxygen content, and the total air volume.

[0065] (5) When the difference between the measured value and the calculated value exceeds the error threshold, the following logic shall be applied for correction: Data from abnormal operating conditions such as mill switching, soot blowing, and periods of significant load fluctuation shall be removed; new measured data for operating conditions shall be added to the database, including data from operating conditions with large deviations; the model shall be refitted / trained; the coal quality influence coefficient shall be corrected, and the model updated. It should be noted that... Figure 6 The actual flame center position in this context refers to the actual horizontal position of the flame center used during correction (the projected position of the flame center on the horizontal section of the furnace (the section parallel to the furnace's deflection angle)).

[0066] The specific error threshold can be set and adjusted by professionals in this field based on measurement error, operating condition fluctuations, safety margins and statistical laws. The embodiments in this application are only illustrative and do not impose specific limitations.

[0067] The first, second, and third models obtained are the calculation models for the actual horizontal position and the actual relative height.

[0068] The theoretical horizontal position can be obtained by using the first model and the theoretical heat load (the expected heat load obtained through thermal calculation or design curve based on parameters such as current unit load, fuel quantity, design coal type, and boiler structure). The theoretical relative height can be obtained by using the average temperature of the ideal flame deflector section (the average temperature of this section under optimal combustion conditions) and the third model.

[0069] Optionally, in one embodiment of this application, the actual horizontal position and actual relative height of the flame center in the furnace are calculated based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section. This includes: determining the wall temperature distribution of the water-cooled wall based on the wall temperature data; calculating the temperature field of the furnace based on the flue gas temperature distribution data of the flame deflector section; calculating the actual heat load in the furnace based on the wall temperature distribution and the temperature field; calculating the actual horizontal position of the flame in the furnace based on the actual heat load; and calculating the average temperature of the flame deflector section based on the flue gas temperature distribution data of the flame deflector section; and determining the actual relative height of the flame based on the average temperature of the flame deflector section.

[0070] In actual implementation, based on the first model used to characterize the relationship between furnace heat load and the horizontal position of the flame center, the second model used to characterize the relationship between furnace heat load and wall temperature distribution and furnace temperature field, and the third model used to characterize the relationship between the average temperature of the flame deflector section and the relative height of the flame center, combined with the wall temperature data of the water-cooled wall and the flue gas temperature distribution data of the flame deflector section of the furnace, the actual horizontal position and actual relative height of the flame center can be calculated in the embodiments of this application.

[0071] For example, this application can extract real-time monitoring data from the water-cooled wall safety detection system—the wall temperature distribution of the water-cooled wall—while simultaneously extracting real-time monitoring data from the furnace temperature field monitoring system—the flue gas temperature distribution data at the flame deflector section.

[0072] The wall temperature distribution of the water-cooled wall can be determined based on the wall temperature data of the water-cooled wall. The temperature field of the furnace can be calculated based on the flue gas temperature distribution data of the flame deflector section. Based on the wall temperature distribution data and the furnace temperature field data, combined with the second model, the actual heat load in the furnace can be calculated. Then, based on the actual heat load in the furnace and the first model, the actual horizontal position of the flame center in the furnace can be calculated.

[0073] The average temperature of the flame deflector section of the furnace can be calculated based on the flue gas temperature distribution data of the flame deflector section. The actual relative height of the flame can be determined by combining the average temperature of the flame deflector section with the third model.

[0074] Meanwhile, based on real-time data of water-cooled wall temperature and furnace temperature field, the database is called to calculate the actual heat load distribution of the furnace and the temperature of the horizontal section of the furnace at the actual flame deflection angle position, and the calculated values ​​are compared with the data under the corresponding operating conditions extracted from the database.

[0075] If the difference between the extracted and calculated values ​​meets the threshold set by the model, the water-cooled wall heat load distribution value is output. The actual furnace flame center position is obtained using a heat load and flame center position prediction model, and the actual relative height position of the furnace flame is obtained using a flame deflector cross-sectional average temperature and flame height position prediction model, thus guiding operational adjustments. If the difference between the extracted and calculated values ​​does not meet the threshold set by the model, the calculation model is corrected, and the actual heat load is recalculated.

[0076] Optionally, in one embodiment of this application, the method further includes: detecting the over-temperature risk of the water-cooled wall based on the wall temperature data and preset over-temperature risk conditions; and when an over-temperature risk is detected, obtaining the first-stage extraction steam pressure and the second-stage extraction steam pressure of the target unit; calculating the first-stage steam flow deviation corresponding to the first-stage extraction steam pressure based on the first-stage extraction steam pressure, and calculating the second-stage steam flow deviation corresponding to the second-stage extraction steam pressure based on the second-stage extraction steam pressure; generating the feedwater flow deviation of the target unit based on the average value of the first-stage steam flow deviation and the second-stage steam flow deviation, so as to generate the feedwater flow regulation action of the target unit based on the feedwater flow deviation; and controlling the target unit to perform the heat load deviation adjustment action and the feedwater flow regulation action until the actual state of the target unit meets the ultra-low load dry-state operation requirements of the target unit.

[0077] Those skilled in the art will understand that the feedwater flow rate is inherently low under low load conditions. If the feedwater control strategy cannot achieve precise adjustment, feedwater overshoot is very likely to occur during rapid load changes. When the feedwater flow rate drops to the protection threshold, it will trigger the main fuel trip (MFT), causing the unit to shut down without fault and seriously affecting the stable operation of the power grid.

[0078] Based on this, in some other embodiments, this application can also modify the feedwater flow rate of the unit on the basis of the main control on the combustion side, and combine the two to ensure the dry-state stable operation of the ultra-low load unit.

[0079] Specifically, this application embodiment designs an additional water supply heating system, which includes, but is not limited to, an additional heater, a pressure matcher, and corresponding pipes and valves.

[0080] in, Figure 7 This is a schematic diagram of the structure of a newly added water supply heating system according to an embodiment of this application. Figure 7 As shown, in this embodiment, the water-side inlet of the new heater is connected to the outlet feedwater pipe of the No. 1 high-pressure heater (hereinafter referred to as "No. 1 high-pressure heater"), and the water-side outlet is connected to the subsequent feedwater pipe; the steam-side inlet of the new heater is connected to the boiler low-temperature superheater outlet steam pipe through a pipe equipped with a pressure reducing valve, for introducing steam after the low-temperature superheater as a heating source; the normal drain outlet of the new heater is connected to the inlet of the No. 1 high-pressure heater through a pipe, and the emergency drain outlet is connected to the deaerator through a pipe; one end of the inlet of the pressure matching device is connected to a section of the boiler extraction steam pipe, and the other end is connected to the steam pipe of the steam-side inlet of the new heater, and the outlet of the pressure matching device is connected to the steam-side inlet of the No. 1 high-pressure heater, for injecting a section of extraction steam into the No. 1 high-pressure heater.

[0081] as well as, Figure 8 This is a schematic diagram of the structure of a water supply coordination control system according to an embodiment of this application. Figure 8As shown, the water supply coordination control system in this embodiment includes, but is not limited to, a data acquisition module, a deviation calculation module, a correction module, and an execution module.

[0082] The data acquisition module is mainly used to collect operating parameters such as the first stage extraction steam pressure of the high-pressure cylinder, the second stage extraction steam pressure, the unit's electrical load, the main steam pressure, the intermediate point temperature (superheat), and the feedwater flow rate. The deviation calculation module is mainly used to calculate the steam flow deviation based on the fixed linear relationship between the extraction steam pressure of the first and second stages of the high-pressure cylinder and the main steam flow. The correction module is mainly used to calculate the feedwater flow deviation by using the average value of the steam flow deviation corresponding to the first and second stage extraction steam pressure deviation, so as to correct the feedwater flow based on the feedwater flow deviation. The execution modules control the adjustment actions of the feedwater main control, fuel main control, and turbine main control respectively.

[0083] The fixed linear relationship between the extraction steam pressure of the first and second stages of the high-pressure cylinder and the main steam flow rate can be, but is not limited to, based on the Flügel formula of the turbine stage or thermodynamic characteristic test data, and supplemented by historical data verification and online correction.

[0084] According to the Flueger formula, the extraction steam pressure of the first and second stages of the high-pressure cylinder is approximately linearly related to the main steam flow rate. Based on this characteristic, by real-time monitoring and calculation of the deviation value of the main steam flow rate under different load conditions, the feedwater flow rate deviation value can be further derived. This deviation value can then be used as a feedforward signal for feedwater control to dynamically correct the feedwater flow rate. For example, corrections can be made through the linear relationship between the deviation value and the correction value, or by multiplying by an experimental coefficient. This effectively improves the feedwater control effect and significantly alleviates the over-adjustment problem of feedwater flow rate under ultra-low load conditions.

[0085] In simple terms, because the steam flow rate of a once-through boiler is equal to the feedwater flow rate, inaccurate feedwater flow rate measurement under low load will cause fluctuations in the main steam flow rate, affecting unit operation. This application's embodiment can calculate the average value of the steam flow rate deviation corresponding to the first and second stage extraction steam pressure deviations based on the correspondence between the first and second stage extraction steam pressures and the main steam flow rate. This average value of the steam flow rate deviation is the feedwater flow rate deviation. Combining the feedwater flow rate deviation with the unit's current actual feedwater flow rate, the actual required feedwater flow rate of the unit can be calculated, thereby correcting the feedwater quantity and ensuring steady-state operation of the unit under ultra-low load conditions.

[0086] After optimizing the pressure control curve and adding a feedwater heating system, the unit's steam flow and operating pressure under low load conditions have both increased, and the high-pressure cylinder extraction steam pressure has also increased accordingly. Figure 9 This is a schematic diagram comparing the effects of water flow rate correction before and after one embodiment of this application. Figure 9As shown, it presents a comparative diagram of unit power, steam flow rate, and extraction steam pressure before and after feedwater correction.

[0087] For example, the water supply coordination control process based on the direct flow balance (DFB) of the newly added water supply heating system in the embodiments of this application can be represented as follows, but is not limited to: (1) Over-temperature risk determination: The embodiments of this application can detect the over-temperature risk of the water-cooled wall based on the wall temperature data of the water-cooled wall and the preset over-temperature risk conditions. When an over-temperature risk is detected in the water-cooled wall, for example, if a target number of wall temperature points in the wall temperature data exceed the corresponding preset wall temperature threshold, or if the wall temperature distribution of the water-cooled wall shows an upward trend (over-temperature trend), or if there is no means to reduce the over-temperature trend, the first auxiliary control action of the target unit is generated based on the steam extraction rate of the target unit, or the second auxiliary control action of the target unit is generated based on the valve status of the target heater in the target unit.

[0088] Here, the target quantity can be understood as the minimum number of wall temperature points (the numerical values ​​corresponding to the wall temperature points) that exceed a preset wall temperature threshold when determining that the water-cooled wall has an overheating risk. If, among the multiple wall temperature points corresponding to the wall temperature distribution data of the water-cooled wall, the number of wall temperature points reaching the preset wall temperature threshold exceeds this minimum number, it can be determined that the water-cooled wall has an overheating risk. The preset wall temperature threshold can be understood as the upper limit that the numerical values ​​corresponding to the wall temperature points cannot exceed. The specific target quantity and preset wall temperature threshold can be set or adjusted by those skilled in the art according to the actual situation. The embodiments in this application are only illustrative and do not impose specific limitations.

[0089] (2) Load-flow relationship correction: When the risk of overheating of the water-cooled wall is detected, based on the fixed linear relationship between the extraction steam pressure of the first and second stages of the high-pressure cylinder and the main steam flow, even if the boundary parameters change, the linear relationship remains unchanged. This characteristic is used to calculate the deviation between the actual steam flow and the design value, and then the feedwater flow deviation is derived. (3) Accurate correction of feedwater flow rate: Real-time collection of the pressure deviation of the first and second stage extraction steam, calculation of the corresponding average value of steam flow rate deviation, and use as the basis for correction of feedwater flow rate, dynamically adjusting the feedwater flow rate set value to avoid feedwater overshoot during rapid load change process; (4) Multi-master coordinated control logic: Under full load conditions, the "constant-sliding-constant" pressure curve is adopted. The turbine master control prioritizes the control of generator power. The feedwater master control adjusts the feedwater flow rate according to the electrical load and the corrected feedwater flow rate setpoint. At the same time, the intermediate point temperature is controlled by slightly adjusting the feedwater flow rate. The main steam pressure is controlled by the fuel master control. The fuel quantity is gradually corrected according to the pressure deviation. The upper and lower limits of the pressure deviation are set. When the pressure deviation exceeds the limit, the turbine master control speed is locked to ensure pressure stability. Through the above coordination logic, the feedwater overshoot triggers the low feedwater flow protection (MFT) when the load is reduced to ultra-low load.

[0090] Optionally, in one embodiment of this application, the method further includes: when an overheating risk is detected in the water-cooled wall, generating a first auxiliary control action of the target unit based on the steam extraction rate of the target unit, or generating a second auxiliary control action of the target unit based on the valve status of the target heater in the target unit; controlling the target unit to perform at least one of the heat load deviation adjustment action, feedwater flow rate regulation action, and the first and second auxiliary control actions, until the actual state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

[0091] In other embodiments, based on the newly added feedwater heating system, this application also designs auxiliary control actions to work together with the main control actions on the combustion side to ensure the dry-state stable operation of the ultra-low load unit.

[0092] Specifically, when an overheating risk is detected in the water-cooled wall, the embodiments of this application can generate a first auxiliary control action of the target unit based on the steam extraction rate of the target unit, or generate a second auxiliary control action of the target unit based on the valve status of the target heater in the target unit.

[0093] The first and second auxiliary control actions can be understood here as executable adjustment actions that can be generated based on the steam extraction rate of the target unit or the valve status of the target heater when there is a risk of overheating in the water-cooled wall. Specifically, the first auxiliary control action is to increase the steam extraction rate, and the second auxiliary control action is to open the emergency drain valve of the newly added heater.

[0094] In this context, the target heater can be understood as a new heater added to the new water supply heating system.

[0095] Then, the embodiments of this application can control the target unit to perform at least one of the following actions: heat load deviation adjustment, feedwater flow regulation, first auxiliary control, and second auxiliary control. That is, control the target unit to perform heat load deviation adjustment, feedwater flow regulation, first auxiliary control, and second auxiliary control simultaneously, or control the target unit to perform heat load deviation adjustment, feedwater flow regulation, first auxiliary control, or second auxiliary control until the actual state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

[0096] For example, the auxiliary control process for ultra-low load dry-state operation of the unit in the embodiments of this application can be represented as follows, but is not limited to: (1) Operation control of the new heating system: Under ultra-low load conditions, the new heater is put into operation. The steam after the boiler low-temperature superheater is reduced to the appropriate pressure through the pressure reducing valve and then introduced into the steam side of the new heater to heat the feedwater after the No. 1 high-pressure heater. During normal operation, the condensate of the new heater is discharged into the No. 1 high-pressure heater. When an abnormal condition occurs (high water level in the heater), the emergency drain valve is opened to discharge the condensate into the deaerator. (2) Pressure Matcher Operation Control: The pressure matcher is put into operation simultaneously, and the high-pressure cylinder first stage extracts steam into the No. 1 high-pressure heater, increasing the steam intake of the No. 1 high-pressure heater, and working together with the new heater to increase the feedwater temperature; when the water-cooled wall is at risk of overheating (the water-cooled wall is already overheating, or there is an overheating trend, or there is no means to reduce the overheating trend), the steam extraction volume is increased or the emergency drain valve of the new heater is opened to increase the steam-water circulation volume of the water-cooled wall, ensuring stable dry operation; (3) Multi-objective coordinated protection: By adding a heating system to increase the feedwater temperature, the economizer outlet water temperature is increased, the heat absorption load of the water-cooled wall is reduced, and stable combustion under low load is ensured; at the same time, the increase in feedwater temperature leads to the increase in flue gas temperature at the inlet of the denitrification system, which meets the activity requirements of the denitrification catalyst and achieves denitrification under wide load; in addition, the extraction of low-temperature superheater outlet steam for heating can increase the main steam temperature under low load conditions and reduce unit energy consumption.

[0097] In summary, the activation conditions for different control measures in this application can be expressed as follows: When the positional deviation between the actual horizontal position and the theoretical horizontal position of the flame center exceeds the preset positional deviation threshold, or the height deviation between the actual relative height and the theoretical relative height exceeds the preset height deviation threshold, combustion adjustment (heat load deviation adjustment) is initiated; when any wall temperature measuring point of the water-cooled wall exceeds 400℃, the wall temperature rises too quickly, or the overall wall temperature shows a continuous upward trend, an overheating risk is determined, and feedwater flow correction (DFB control) is initiated; if the overheating risk is severe (e.g., multiple wall temperatures exceed 420℃) or the overheating trend cannot be suppressed after feedwater flow correction, auxiliary control is further initiated (increasing steam extraction or opening the emergency drain valve of the newly added heater).

[0098] The priority of the three, from highest to lowest, is: auxiliary control (the fastest and most direct over-temperature protection method) > water supply flow correction (preventive feedforward regulation) > combustion adjustment (a slower optimization method).

[0099] During auxiliary control actions, instructions that may further increase the heat load during combustion adjustment are blocked (such as prohibiting the downward movement of the flame center or the increase of the secondary air volume in the lower layer); during feedwater flow correction actions, combustion adjustments that are opposite to the feedwater flow are temporarily prohibited (such as prohibiting a significant increase in fuel quantity); combustion adjustment and feedwater flow correction can be carried out simultaneously, and their actuators do not conflict with each other.

[0100] In each control cycle, the coordinated timing of the three can be, but is not limited to, expressed as follows: First, all data are collected simultaneously (0~0.5s), then the over-temperature risk and flame center deviation are judged simultaneously (0.5~1.0s), and then a decision is made to execute: If there is an over-temperature risk, auxiliary control and water supply flow correction are executed first, and combustion adjustment is executed according to the flame center deviation after the over-temperature risk drops to a safe level; if there is no over-temperature risk but the flame center deviation exceeds the threshold, only combustion adjustment is executed; if neither of the above is true, only the normal intermediate point temperature control is maintained.

[0101] Furthermore, in this embodiment, the processes of "detecting overheating risk first and then adjusting combustion" or "adjusting simultaneously" are not executed sequentially. Instead, all data is collected simultaneously in real time, but overheating risk is given higher priority in control decisions. Specifically, the water-cooled wall temperature and the flame deflector section temperature field are monitored synchronously. Once an overheating risk is detected, water flow correction and auxiliary control are immediately initiated to quickly intervene in the safety of the water-cooled wall. Combustion adjustment can be performed simultaneously or later, but should not be at the expense of water-cooled wall safety. If there is no overheating risk, combustion adjustment is performed solely based on the flame center deviation to optimize combustion uniformity.

[0102] The present application will be explained in detail below with reference to a specific embodiment.

[0103] Implementation process: (1) Water-cooled wall overheat risk assessment and dry state maintenance: The three-dimensional temperature network data collected by the water-cooled wall safety detection system is used to simulate the heat load field of the vertical water-cooled wall area to determine whether there is an overheat risk in the water-cooled wall (for example, the safe operation of the water-cooled wall is used as the basis for controlling the lowest point of the boiler feedwater. When the wall temperature in a certain area is detected to be close to or exceed 400℃, it is determined that there is an overheat risk).

[0104] When there is a risk of overheating, a feedwater flow adjustment or heat load deviation correction command (including auxiliary control commands) is triggered to avoid switching to wet operation; the first derivative of the transformation values ​​of each parameter in the longitudinal field is used as a factor to judge the rate of wall temperature change and serves as an early warning value. The heat absorption of the furnace cross-section is obtained through the longitudinal temperature field to determine the changes in the flame center.

[0105] (2) Intermediate point temperature (superheat) control: Under ultra-low load conditions, the intermediate point temperature is controlled by adjusting the coal-water ratio. The lower limit of superheat control is set to 10℃, and the upper limit is determined according to the highest point wall temperature monitored by the water-cooled wall safety detection system to ensure that the highest point wall temperature does not exceed 400℃. (3) Optimization of sliding pressure curve: The "constant-sliding-constant" pressure control curve is adopted. For ultra-low load conditions below 30%, constant pressure operation mode is selected, and the main steam pressure is controlled within the range of 13±1MPa; for loads above 30%, sliding pressure operation is adopted according to the design conditions. (4) Elimination of furnace side heat load deviation: The furnace side heat load distribution is obtained through the furnace temperature field monitoring system. Combined with the water-cooled wall temperature distribution data, furnace oxygen distribution data and desuperheating water temperature distribution data, the location and degree of heat load deviation are comprehensively judged. The furnace side heat load deviation is corrected by adjusting the burner swing angle, pulverized coal feed rate or desuperheating water flow rate, etc., to ensure the uniformity of furnace combustion, and thus ensure the steady-state operation of the unit under ultra-low load.

[0106] At the same time, determine whether water supply control and auxiliary control are necessary based on the actual situation.

[0107] Taking a 600MW supercritical coal-fired power unit as an example: (1) Equipment layout: One temperature measuring point is arranged along the circumference of each water-cooled wall at the outlet of the vertical water-cooled wall of the boiler, and five temperature measuring points are arranged longitudinally along the vertical water-cooled walls of the front, rear, left and right walls to form a three-dimensional temperature network; an infrared thermometer is installed in the lower area of ​​the flame deflector to form a furnace temperature field monitoring system; the new heater is a U-tube heat exchanger, the water-side flow rate is matched to 100% of the unit's maximum feedwater flow rate, and the steam-side inlet pressure reducing valve adjustment range is 0.5-3MPa; the pressure matching device ejector capacity is 20% of the rated flow rate of the first stage extraction steam; (2) Control parameter settings: The lower limit of superheat control is 10℃, and the upper limit is set to 400℃ based on the highest point wall temperature of the water-cooled wall; constant pressure operation below 30% load, with pressure set to 13±1MPa; pressure deviation upper and lower limits are set to ±0.5MPa; (3) Operation process: When the unit load drops to 30% (180MW), the new heater and pressure matcher are put into operation. The steam after the low temperature superheater is depressurized to 2MPa through the pressure reducing valve and introduced into the new heater. The pressure matcher injects the first stage of extraction steam into the No.1 high-pressure heater. The water-cooled wall safety detection system monitors the wall temperature in real time. The three-dimensional temperature network data shows that the highest wall temperature is 385℃ and the superheat is controlled at 15℃. The furnace temperature field monitoring system finds that the heat load on the left wall is too high. The heat load deviation is reduced by adjusting the coal feed rate of the left burner. During the rapid load reduction process, the feedwater coordination control system calculates the steam flow deviation through the pressure deviation of the first and second stage extraction steam, corrects the feedwater flow set value, avoids feedwater overshoot, and the feedwater flow is stable within ±3% of the design value. The unit operates stably for 4 hours under this load. The dry state operation is stable. The inlet flue gas temperature of the denitrification system is maintained above 320℃. The coal consumption is reduced by 8g / kWh compared with the existing technology. There is no risk of feedwater overshoot or MFT trigger.

[0108] According to the ultra-low load dry-state operation control method of the unit proposed in this application, the water-cooled wall safety detection system and heat load deviation correction strategy can ensure that the unit operates in a dry state at more than 20% load, avoiding the safety risks caused by frequent switching between dry and wet states and improving the unit's deep peak-shaving capability. By adding a heating system to increase the feedwater temperature, the inlet flue gas temperature of the denitrification system is increased, meeting the denitrification catalyst activity requirements under low load conditions, achieving nitrogen oxide emissions in compliance with standards across the entire load range, and solving the problem of wide-load denitrification. By adding a heating system and working in conjunction with the pressure matcher, the steam-water circulation volume of the water-cooled wall is increased, ensuring hydrodynamic safety. At the same time, the economizer outlet water temperature is increased, reducing the heat absorption load of the water-cooled wall, which is conducive to stable combustion under low load and improving hydrodynamic safety and stable combustion capability. By extracting low-temperature superheater outlet steam for heating, the main steam temperature is increased, reducing energy loss under low load conditions and reducing unit coal consumption. The feedwater flow rate is dynamically corrected by utilizing the fixed relationship between extraction steam pressure and steam flow rate to achieve precise feedwater control, avoiding feedwater overshoot during rapid load changes, preventing MFT triggered by low feedwater flow rate, and ensuring safe and stable unit operation. This solves the problems in related technologies, such as delayed response at ultra-low loads, easy overshooting of feedwater control, poor stability during dry operation, poor furnace combustion stability during low-load dry operation, significantly increased energy consumption, and decreased flue gas temperature, which cannot meet the activity requirements of denitrification catalysts, making it difficult to achieve wide-load denitrification, poor adaptability in practical applications, seriously affecting the safety and economy of the unit, and failing to meet the strict requirements of coal-fired power indicators for deep peak shaving of coal-fired units.

[0109] Next, with reference to the accompanying drawings, the ultra-low load dry-state operation control device for the unit proposed according to the embodiments of this application is described.

[0110] Figure 10This is a schematic diagram of the structure of the ultra-low load dry-state operation control device of the unit according to an embodiment of this application.

[0111] like Figure 10 As shown, the ultra-low load dry-state operation control device 10 of the unit includes: a first calculation module 100, a first determination module 200 and a first control module 300.

[0112] The first calculation module 100 is used to calculate the actual horizontal position and actual relative height of the flame center in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace; the first determination module 200 is used to determine the actual combustion center of the furnace based on the actual horizontal position and actual relative height when the position deviation between the actual horizontal position and the theoretical horizontal position is greater than a preset position deviation threshold or the height deviation between the actual relative height and the theoretical relative height is greater than a preset height deviation threshold; the first control module 300 is used to generate a furnace heat load deviation adjustment action based on the actual combustion center, so as to control the target unit to perform the heat load deviation adjustment action until the actual operating state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

[0113] Optionally, in one embodiment of this application, the first calculation module 100 includes: a first calculation unit, configured to determine the wall temperature distribution of the water-cooled wall based on wall temperature data, calculate the temperature field of the furnace based on the flue gas temperature distribution data of the flame deflector section, calculate the actual heat load in the furnace based on the wall temperature distribution and temperature field, and calculate the actual horizontal position of the flame in the furnace based on the actual heat load; and a second calculation unit, configured to calculate the average temperature of the flame deflector section of the furnace based on the flue gas temperature distribution data of the flame deflector section, and determine the actual relative height of the flame based on the average temperature of the flame deflector section.

[0114] Optionally, in one embodiment of this application, it further includes: a construction module, used to construct, before calculating the actual horizontal position and actual relative height of the flame in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace, a first model for characterizing the relationship between the furnace heat load and the horizontal position of the flame center, a second model for characterizing the relationship between the furnace heat load and the wall temperature distribution and the furnace temperature field, and a third model for characterizing the relationship between the average temperature of the flame deflector section and the relative height of the flame center; and a second determination module, used to determine the calculation model for the actual horizontal position and actual relative height based on the first model, the second model and the third model.

[0115] Optionally, in one embodiment of this application, it further includes: a detection module, used to detect the over-temperature risk of the water-cooled wall based on the wall temperature data of the water-cooled wall and preset over-temperature risk conditions, and to obtain the first-stage extraction steam pressure and the second-stage extraction steam pressure of the target unit when the over-temperature risk of the water-cooled wall is detected; a second calculation module, used to calculate the first-stage steam flow deviation corresponding to the first-stage extraction steam pressure based on the first-stage extraction steam pressure, and to calculate the second-stage steam flow deviation corresponding to the second-stage extraction steam pressure based on the second-stage extraction steam pressure; a first generation module, used to generate the feedwater flow deviation of the target unit based on the average value of the first-stage steam flow deviation and the second-stage steam flow deviation, so as to generate the feedwater flow adjustment action of the target unit based on the feedwater flow deviation; and a second control module, used to control the target unit to perform the heat load deviation adjustment action and the feedwater flow adjustment action until the actual state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

[0116] Optionally, in one embodiment of this application, it further includes: a second generation module, used to generate a first auxiliary control action of the target unit based on the steam extraction rate of the target unit, or to generate a second auxiliary control action of the target unit based on the valve status of the target heater in the target unit when an overheating risk is detected in the water-cooled wall; and a third control module, used to control the target unit to perform at least one of the heat load deviation adjustment action, feedwater flow regulation action, and the first and second auxiliary control actions, until the actual state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

[0117] It should be noted that the foregoing explanation of the embodiment of the ultra-low load dry-state operation control method for the unit also applies to the ultra-low load dry-state operation control device of the unit in this embodiment, and will not be repeated here.

[0118] According to the ultra-low load dry-state operation control device of the unit proposed in the embodiments of this application, the unit can ensure dry-state operation at more than 20% load through the water-cooled wall safety detection system and heat load deviation correction strategy, avoiding the safety risks caused by frequent dry-wet state switching and improving the unit's deep peak-shaving capability; by adding a heating system to increase the feedwater temperature, thereby increasing the inlet flue gas temperature of the denitrification system, meeting the denitrification catalyst activity requirements under low load conditions, achieving nitrogen oxide emissions in compliance with standards across the entire load range, and solving the problem of wide-load denitrification; by adding a heating system and working in conjunction with the pressure matcher, the steam-water circulation volume of the water-cooled wall is increased, ensuring hydrodynamic safety; at the same time, the economizer outlet water temperature is increased, reducing the heat absorption load of the water-cooled wall, which is conducive to stable combustion under low load and improving hydrodynamic safety and stable combustion capability; by extracting low-temperature superheater outlet steam for heating, the main steam temperature is increased, reducing energy loss under low load conditions and reducing unit coal consumption; by using the fixed relationship between extraction steam pressure and steam flow rate to dynamically correct feedwater flow rate, precise feedwater control is achieved, avoiding feedwater overshoot during rapid load changes, preventing MFT triggered by low feedwater flow rate, and ensuring safe and stable unit operation. This solves the problems in related technologies, such as delayed response at ultra-low loads, easy overshooting of feedwater control, poor stability during dry operation, poor furnace combustion stability during low-load dry operation, significantly increased energy consumption, and decreased flue gas temperature, which cannot meet the activity requirements of denitrification catalysts, making it difficult to achieve wide-load denitrification, poor adaptability in practical applications, seriously affecting the safety and economy of the unit, and failing to meet the strict requirements of coal-fired power indicators for deep peak shaving of coal-fired units.

[0119] Figure 11 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 1101, the processor 1102, and the computer program stored on the memory 1101 and executable on the processor 1102.

[0120] When the processor 1102 executes the program, it implements the ultra-low load dry-state operation control method for the unit provided in the above embodiments.

[0121] Furthermore, electronic devices also include: Communication interface 1103 is used for communication between memory 1101 and processor 1102.

[0122] The memory 1101 is used to store computer programs that can run on the processor 1102.

[0123] The memory 1101 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage.

[0124] If the memory 1101, processor 1102, and communication interface 1103 are implemented independently, then the communication interface 1103, memory 1101, and processor 1102 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 11 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0125] Optionally, in a specific implementation, if the memory 1101, processor 1102, and communication interface 1103 are integrated on a single chip, then the memory 1101, processor 1102, and communication interface 1103 can communicate with each other through an internal interface.

[0126] The processor 1102 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0127] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described ultra-low load dry-state operation control method for the unit.

[0128] This application also provides a computer program product, including a computer program that can run computer instructions. When the computer instructions are executed by a processor, they implement the ultra-low load dry-state operation control method for the unit provided in this application.

[0129] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0130] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0131] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0132] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0133] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0134] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0135] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0136] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for controlling ultra-low load dry-state operation of a generating unit, characterized in that, Includes the following steps: Based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace, the actual horizontal position and actual relative height of the flame center in the furnace are calculated. When the positional deviation between the actual horizontal position and the theoretical horizontal position is greater than a preset positional deviation threshold, or when the height deviation between the actual relative height and the theoretical relative height is greater than a preset height deviation threshold, the actual combustion center of the furnace is determined based on the actual horizontal position and the actual relative height. Based on the actual combustion center, a heat load deviation adjustment action is generated in the furnace to control the target unit to perform the heat load deviation adjustment action until the actual operating state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

2. The method according to claim 1, characterized in that, The calculation of the actual horizontal position and actual relative height of the flame center within the furnace, based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section, includes: The wall temperature distribution of the water-cooled wall is determined based on the wall temperature data, and the temperature field of the furnace is calculated based on the flue gas temperature distribution data of the flame deflector section. Based on the wall temperature distribution and the temperature field, the actual heat load in the furnace is calculated, and the actual horizontal position of the flame in the furnace is calculated based on the actual heat load. The average temperature of the flame deflector section of the furnace is calculated based on the flue gas temperature distribution data of the flame deflector section, and the actual relative height of the flame is determined based on the average temperature of the flame deflector section.

3. The method according to claim 1, characterized in that, Before calculating the actual horizontal position and actual relative height of the flame in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace, the method further includes: Based on wall temperature distribution data, furnace temperature field data, furnace heat load data, and horizontal position data of flame center of multiple target units under target combustion conditions, a first model is constructed to characterize the relationship between furnace heat load and horizontal position of flame center; a second model is constructed to characterize the relationship between furnace heat load and wall temperature distribution and furnace temperature field; and a third model is constructed to characterize the relationship between average temperature of flame deflector section and relative height of flame center. A calculation model is used to determine the actual horizontal position and the actual relative height based on the first model, the second model, and the third model.

4. The method according to claim 1, characterized in that, Also includes: Based on the wall temperature data of the water-cooled wall and the preset over-temperature risk conditions, the over-temperature risk of the water-cooled wall is detected, and when the over-temperature risk of the water-cooled wall is detected, the first stage extraction steam pressure and the second stage extraction steam pressure of the target unit are obtained. Calculate the steam flow deviation corresponding to the first stage extraction pressure based on the first stage extraction pressure, and calculate the steam flow deviation corresponding to the second stage extraction pressure based on the second stage extraction pressure. Based on the average of the first-stage steam flow deviation and the second-stage steam flow deviation, the feedwater flow deviation of the target unit is generated, and the feedwater flow regulation action of the target unit is generated based on the feedwater flow deviation. The target unit is controlled to perform the heat load deviation adjustment action and the feedwater flow regulation action until the actual state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

5. The method according to claim 4, characterized in that, Also includes: When an overheating risk is detected in the water-cooled wall, a first auxiliary control action of the target unit is generated based on the steam extraction rate of the target unit, or a second auxiliary control action of the target unit is generated based on the valve status of the target heater in the target unit. The target unit is controlled to perform at least one of the heat load deviation adjustment action, the feedwater flow regulation action, and the first auxiliary control action and the second auxiliary control action until the actual state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

6. A control device for ultra-low load dry-state operation of a generator unit, characterized in that, include: The calculation module is used to calculate the actual horizontal position and actual relative height of the flame center in the furnace based on the wall temperature data of the water-cooled wall of the target unit and the flue gas temperature distribution data of the flame deflector section of the furnace. The determination module is used to determine the actual combustion center of the furnace based on the actual horizontal position and the actual relative height when the position deviation between the actual horizontal position and the theoretical horizontal position is greater than a preset position deviation threshold or the height deviation between the actual relative height and the theoretical relative height is greater than a preset height deviation threshold. The adjustment module is used to generate a heat load deviation adjustment action for the furnace based on the actual combustion center, so as to control the target unit to perform the heat load deviation adjustment action until the actual operating state of the target unit meets the ultra-low load dry state operation requirements of the target unit.

7. The apparatus according to claim 6, characterized in that, The computing module includes: The first calculation unit is used to determine the wall temperature distribution of the water-cooled wall based on the wall temperature data, calculate the temperature field of the furnace based on the flue gas temperature distribution data of the flame deflector section, calculate the actual heat load in the furnace based on the wall temperature distribution and the temperature field, and calculate the actual horizontal position of the flame in the furnace based on the actual heat load. The second calculation unit is used to calculate the average temperature of the flame deflector section of the furnace based on the flue gas temperature distribution data of the flame deflector section, so as to determine the actual relative height of the flame based on the average temperature of the flame deflector section.

8. An electronic device, characterized in that, include: The unit includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the ultra-low load dry-state operation control method for the unit as described in any one of claims 1-5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the ultra-low load dry-state operation control method for the unit as described in any one of claims 1-5.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed, it is used to implement the ultra-low load dry-state operation control method for the unit as described in any one of claims 1-5.

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