Boiler hot standby maintenance device and control method

Abstract

The application discloses a boiler heat standby maintaining device and a control method, relates to the technical field of peak regulation of thermal power generating units, and the device comprises an active power first unit provided with a running boiler, a second unit provided with a heat standby boiler, a flue gas conveying unit, a flue gas conditioning unit and a heat standby controller; the flue gas conveying unit is provided with a plurality of flue gas extraction points corresponding to different temperature intervals along a flue of the running boiler, and the flue gas extraction amount and the extraction flue gas temperature can be adjusted and controlled; the flue gas conditioning unit is used for adjusting the flue gas temperature conveyed to the heat standby boiler; the heat standby controller predefines a wall temperature target interval, determines the lowest inlet flue gas temperature based on collected data, takes the condition that the inlet flue gas temperature is not lower than the lowest value as a rigid constraint, and maintains the wall temperature in the target interval through closed-loop regulation and control. The application solves the problems of poor flue gas regulation flexibility, easy interference with the running unit, and incapability of considering the starting efficiency and corrosion safety in the prior art, and is suitable for the deep peak regulation demand of a power grid.

Description

Technical Field

[0001] This application belongs to the field of peak shaving technology for thermal power units, and relates to a boiler thermal standby maintenance device and control method. Background Technology

[0002] In a power grid operating environment with a high proportion of new energy installed capacity, coal-fired power units, as the main peak-shaving and backup power sources of the power grid, need to frequently participate in deep peak-shaving and two-shift start-up and shutdown operations. This requires that boilers that are shut down maintain a stable hot state throughout the standby period in order to meet the rapid grid connection and start-up requirements issued by the power grid dispatch. As a result, higher requirements are placed on the safety, economy and operating condition adaptability of boiler hot standby maintenance technology.

[0003] Existing boiler hot standby maintenance technologies generally suffer from drawbacks such as rapid cooling of standby boilers, high energy consumption during restart, and long grid connection cycles. Existing flue gas waste heat utilization insulation solutions cannot flexibly adjust the flue gas extraction volume and transmission temperature, which can easily lead to low-temperature corrosion of the tail heating surface. Furthermore, flue gas extraction can easily interfere with the normal active power output of the operating unit, making it difficult to simultaneously ensure hot standby start-up efficiency, equipment safety, and the stability of the operating unit.

[0004] Therefore, there is an urgent need for a boiler hot standby maintenance device that can utilize waste heat from flue gas to maintain the hot state, flexibly adjust flue gas extraction parameters, precisely regulate the temperature of the delivered flue gas, and simultaneously ensure the rapid start-up capability of the hot standby boiler, equipment corrosion safety, and stable operation of the operating unit. Summary of the Invention

[0005] This application provides a boiler hot standby maintenance device and control method. By constructing a dual flue gas temperature control system through multi-stage flue gas outlets and independent flue gas conditioning units, the boiler wall temperature is controlled in a closed loop with the lowest inlet flue gas temperature as a rigid constraint. This achieves stable hot state maintenance and low-interference operation of the hot standby boiler, solving the defects of existing technologies such as poor flue gas control flexibility, easy interference with operating units, and inability to balance start-up efficiency and corrosion safety.

[0006] In a first aspect, this application provides a boiler hot standby maintenance device, including a first unit with active power output and a second unit in hot standby state. The first unit is equipped with an operating boiler, and the second unit is equipped with a hot standby boiler. The device further includes a flue gas conveying unit, a flue gas conditioning unit, and a hot standby controller. The flue gas conveying unit connects the operating boiler and the hot standby boiler. The flue gas conveying unit has multiple flue gas outlets along the flue gas flow direction of the operating boiler flue, and the flue gas temperature drawn from each of the flue gas outlets corresponds to different temperature ranges. The flue gas conveying unit is used to draw flue gas from the operating boiler and convey the flue gas to the hot standby boiler, and to regulate the flow rate by adjusting the opening and closing of each flue gas outlet and the flue gas flow rate. The flue gas extraction rate and temperature; a flue gas conditioning unit is installed on the pipeline of the flue gas conveying unit to regulate the temperature of the flue gas delivered to the hot standby boiler; a hot standby controller is electrically connected to the flue gas conveying unit, the flue gas conditioning unit, the first unit, and the second unit respectively; the hot standby controller is configured to: preset the target wall temperature range of the hot standby boiler; collect real-time operating data and environmental parameters of the first unit and the second unit, and determine the minimum inlet flue gas temperature of the hot standby boiler based on the collected data; regulate the operation of the flue gas conveying unit and the flue gas conditioning unit, and maintain the wall temperature of the hot standby boiler within the target wall temperature range under the constraint that the flue gas temperature at the inlet of the hot standby boiler is not lower than the minimum inlet flue gas temperature.

[0007] The boiler hot standby maintenance device provided in this application utilizes the natural flue gas temperature gradient characteristics of the boiler flue. Multiple staged flue gas outlets are arranged along the flue gas flow direction, each outlet corresponding to a different fixed flue gas temperature range. By opening and closing different outlets, the appropriate flue gas temperature can be directly obtained from the source, achieving a large-range, energy-free coarse adjustment of the flue gas temperature. Basic flue gas temperature matching can be achieved without significantly changing the total amount of flue gas extracted, fundamentally reducing the interference of flue gas extraction on the active power output of the operating unit. Simultaneously, based on the coarse adjustment of the staged outlets, independent flue gas outlets are connected in series... The controlled atmosphere unit enables precise fine adjustment of flue gas temperature, constructing a dual temperature regulation system of "stepped coarse adjustment + linear fine adjustment". The coarse adjustment enables flue gas temperature to adapt to a wide range of operating conditions, while the fine adjustment achieves continuous linear and precise adjustment of flue gas temperature based on the principle of adiabatic mixing energy balance. The two complement each other, covering the full range of flue gas temperature requirements of different heat standby levels and achieving high-precision flue gas temperature control. This solves the technical defect of existing technologies that cannot balance flue gas temperature adjustment range and control accuracy. There is no need to adjust the combustion parameters of the operating boiler throughout the process, and it will not affect the grid load response capability of the operating unit.

[0008] In addition, the device provided in this application breaks through the design limitations of the existing technology with a single wall temperature control target. It takes the minimum inlet flue gas temperature of the hot standby boiler as a rigid constraint, and its control priority is always higher than the wall temperature regulation priority. This prevents low-temperature flue gas below the acid dew point from entering the boiler, solves the industry pain point of low-temperature corrosion of the tail heating surface during hot standby, and maintains the wall temperature in the target range in a closed loop within the safety constraint boundary. It also takes into account the rapid grid connection and start-up capability of the hot standby boiler, and achieves the unity of equipment safety, operating economy and grid response capability.

[0009] In some embodiments of this application, the hot standby controller is configured to: preset screening rules for flue gas outlet points; the screening rules include at least one of the following rules: the flue gas temperature at the flue gas outlet point is not lower than the minimum inlet flue gas temperature; the flue gas pressure at the flue gas outlet point is greater than the flue gas pressure at the inlet of the hot standby boiler; the total flue gas outflow ratio of all opened flue gas outlet points does not exceed the preset maximum allowable upper limit of the total flue gas flow of the operating boiler; select a target flue gas outlet point that meets the screening rules from all flue gas outlet points, and open the target flue gas outlet point to allow flue gas to be drawn out from the operating boiler; when all the flue gas outlet points do not meet the screening rules, select the flue gas outlet point located upstream along the flue gas flow direction from all the flue gas outlet points as the target flue gas outlet point, and start the flue gas conditioning unit to cool down the flue gas temperature delivered to the hot standby boiler.

[0010] In some embodiments of this application, the flue gas conditioning unit includes a mixing chamber, a blending branch, and a blending regulating valve; one end of the blending branch is connected to the mixing chamber, and the other end is connected to a cooling medium; the blending regulating valve is disposed on the blending branch; the mixing chamber is connected in series to the main pipeline of the flue gas conveying unit for mixing the flue gas of the flue gas conveying unit with the cooling medium introduced by the blending branch; the hot standby controller controls the amount of cold end medium introduced by adjusting the opening of the blending regulating valve, thereby adjusting the temperature of the flue gas delivered to the hot standby boiler.

[0011] In some embodiments of this application, the main pipeline of the flue gas conveying unit is divided into a furnace conveying branch and a convection flue conveying branch upstream of the flue gas inlet of the hot standby boiler. The outlet of the furnace conveying branch is connected to the furnace cavity of the hot standby boiler, and the outlet of the convection flue conveying branch is connected to the convection flue at the tail of the hot standby boiler. Distribution baffles are respectively provided on the furnace conveying branch and the convection flue conveying branch. The distribution baffles are used to cut off the flue gas passage of the furnace conveying branch and the convection flue conveying branch, and to regulate the flue gas conveying flow rate of the furnace conveying branch and the convection flue conveying branch.

[0012] In some embodiments of this application, the hot standby controller is configured to: dynamically update control commands during the boiler hot standby maintenance phase to maintain the wall temperature of the hot standby boiler within a preset target wall temperature range; the rules for updating the control commands by the hot standby controller include: when the wall temperature of the hot standby boiler is lower than the lower limit of the target wall temperature range, increasing the flue gas outflow or increasing the flue gas flow rate of the furnace conveying branch; when the flue gas temperature at the inlet of the hot standby boiler is lower than the minimum inlet flue gas temperature, reducing the mixing ratio of the cooling medium, or controlling the currently open flue gas outflow point to close and the upstream flue gas outflow point to open; when the wall temperature of the hot standby boiler is higher than the upper limit of the target wall temperature range, reducing the flue gas outflow or increasing the mixing ratio of the cooling medium.

[0013] In some embodiments of this application, the flue gas outlet is provided with an isolation baffle and a flow regulating component. The isolation baffle is used to cut off the flue gas passage at the corresponding flue gas outlet, and the flow regulating component is used to regulate the flue gas outlet flow rate at the corresponding staged flue gas outlet.

[0014] In some embodiments of this application, a safety interlock protection unit is also included. The safety interlock protection unit includes a series double isolation baffle, a check valve structure, a purging circuit, and a pressure relief assembly. The series double isolation baffle is disposed at the flue gas outlet of the flue gas conveying unit and is used to cut off the flue gas passage between the operating boiler and the flue gas conveying unit. The check valve structure is disposed on the pipeline of the flue gas conveying unit and is used to block the reverse flow of flue gas from the hot standby boiler side to the operating boiler side. The purging circuit is connected to the pipeline of the flue gas conveying unit and removes combustible gas and acidic flue gas accumulated in the pipeline by introducing inert gas into the pipeline of the flue gas conveying unit. The pressure relief assembly is disposed at the end of the pipeline of the flue gas conveying unit and upstream of the flue gas inlet of the hot standby boiler and is used to discharge the flue gas in the pipeline when the pipeline is overpressured.

[0015] In some embodiments of this application, the hot standby controller is configured to: preset multiple hot standby levels corresponding to grid-connected start-up durations, and wall temperature target ranges corresponding to each hot standby level; collect the wall temperature and inlet flue gas temperature of the hot standby boiler in real time, calculate the deviation value of the real-time wall temperature relative to the wall temperature target range, and the difference between the inlet flue gas temperature and the lowest inlet flue gas temperature; and based on the magnitude of the deviation value and the difference, adjust the flue gas output and temperature of the flue gas conveying unit, and adjust the flue gas temperature delivered to the hot standby boiler by the flue gas conditioning unit.

[0016] In some embodiments of this application, the hot standby controller is configured to: preset an acid dew point margin matching the hot standby level of the second unit; calculate the flue gas acid dew point temperature of the hot standby boiler based on the collected sulfur content of the coal entering the furnace of the first unit, the humidity parameters of the environment in which the unit is located, and the wall temperature and furnace humidity data of the hot standby boiler of the second unit; and determine the minimum inlet flue gas temperature based on the flue gas acid dew point temperature and the acid dew point margin.

[0017] Secondly, this application also provides a boiler hot standby maintenance control method, implemented based on the aforementioned boiler hot standby maintenance device. The method is controlled and executed by a hot standby controller, including: presetting a target range for the wall temperature of the hot standby boiler; collecting real-time operating data and environmental parameters of the first unit and the second unit, and determining the minimum inlet flue gas temperature of the hot standby boiler based on the collected data; adjusting the flue gas outflow and the flue gas temperature delivered to the hot standby boiler, and maintaining the wall temperature of the hot standby boiler within the target range under the constraint that the flue gas temperature at the inlet of the hot standby boiler is not lower than the minimum inlet flue gas temperature.

[0018] The boiler thermal standby maintenance device and control method provided in this application have at least the following beneficial effects: 1. Based on multi-dimensional screening rules, intelligent matching of flue gas outlet points is achieved, prioritizing the selection of compliant low-temperature flue gas to minimize the impact on the efficiency of operating boilers, while balancing energy consumption optimization and unit operation stability.

[0019] 2. The dual-branch targeted delivery structure enables precise heating of the heated surface in zones. Combined with dynamic control rules for different scenarios, it can quickly correct operating condition deviations and adapt to the differentiated needs of different heat standby levels without significantly adjusting the total flue gas output.

[0020] 3. By adopting a dynamic acid dew point margin and graded control logic that matches the hot standby level, the technical contradiction of fixed parameters being unable to balance start-up efficiency and corrosion prevention safety is resolved, achieving the optimal match between safety and economy under different standby scenarios.

[0021] 4. The full-process redundant safety interlock protection system can effectively prevent safety risks such as flue gas backflow, leakage, and overpressure, and ensure the long-term stable operation of the system; the supporting control methods and devices form a complete invention closed loop, with full-process automated control and strong engineering feasibility.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more apparent, specific embodiments of this application are given below. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the boiler thermal standby maintenance device of this application; Figure 2 This is a flowchart of the boiler hot standby maintenance method of this application.

[0025] In the diagram: 1. Operating boiler; 2. Hot standby boiler; 3. Furnace cavity; 4. Main flue gas conveying route; 5. Flue gas outlet point; 6. Flue gas outlet fan; 7. Flow regulating component; 8. Booster fan; 9. Furnace conveying branch route; 10. Convection flue conveying branch route; 11. Distribution baffle; 12. Mixing chamber; 13. Blending branch route; 14. Blending regulating valve. Detailed Implementation

[0026] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0027] The prefixes such as "first" and "second" used in this application embodiment are merely for distinguishing different descriptive objects and do not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes used to distinguish descriptive objects in this application embodiment does not constitute a limitation on the described objects. The description of the described objects is given in the claims or the context of the embodiments, and should not constitute unnecessary restrictions due to the use of such prefixes. Furthermore, in the description of this embodiment, unless otherwise stated, "multiple" means two or more.

[0028] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0029] In the embodiments provided in this application, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0030] In a power grid operating environment with a high proportion of new energy installed capacity, coal-fired power units, as the main peak-shaving and backup power sources of the power grid, need to frequently participate in deep peak-shaving and two-shift start-up and shutdown operations. This requires that boilers that are shut down maintain a stable hot state throughout the standby period in order to meet the rapid grid connection and start-up requirements issued by the power grid dispatch. As a result, higher requirements are placed on the safety, economy and operating condition adaptability of boiler hot standby maintenance technology.

[0031] Existing boiler hot standby maintenance technologies generally suffer from drawbacks such as rapid cooling of standby boilers, high energy consumption during restart, and long grid connection cycles. Existing flue gas waste heat utilization insulation solutions cannot flexibly adjust the flue gas extraction volume and transmission temperature, which can easily lead to low-temperature corrosion of the tail heating surface. Furthermore, flue gas extraction can easily interfere with the normal active power output of the operating unit, making it difficult to simultaneously ensure hot standby start-up efficiency, equipment safety, and the stability of the operating unit.

[0032] Therefore, as Figure 1 As shown, in order to overcome the shortcomings of the prior art, this embodiment proposes a boiler thermal standby maintenance device.

[0033] The boiler hot standby maintenance device of this embodiment is mainly applied to multi-unit coal-fired power plants, including a first unit that undertakes active power output and a second unit that is in hot standby state. The first unit is equipped with an operating boiler 1, which undertakes a medium load of grid dispatch during operation, and the fuel combustion and flue gas emissions are stable, providing a stable source of flue gas waste heat for the system. The second unit is equipped with a hot standby boiler 2, which does not generate electricity through the grid and maintains a hot state range that can be quickly started throughout the process. It is the object of hot state maintenance of this device.

[0034] In some embodiments, the boiler hot standby maintenance device of this application includes a flue gas conveying unit. The flue gas conveying unit is the core carrier for cross-furnace flue gas waste heat conveying. Its inlet end is connected to the flue of the operating boiler 1 of the first unit, and its outlet end is connected to the hot standby boiler 2 of the second unit. Its core functions are to draw flue gas from the operating boiler 1, stably convey the flue gas to the hot standby boiler 2, and accurately adjust the flue gas drawing amount and the drawing temperature.

[0035] In some embodiments, the specific structure of the flue gas conveying unit includes: 3 to 7 graded flue gas outlet points 5 arranged sequentially along the flue gas flow direction of the operating boiler 1 flue, a main flue gas conveying path 4, a booster fan 8, a furnace conveying branch path 9 and a convection flue conveying branch path 10 at the end, and a matching actuator.

[0036] In some embodiments, the flue gas outlets 5 are arranged sequentially upstream and downstream along the flue gas flow direction. The flue gas temperature at the upstream outlet is higher, and the flue gas temperature at the downstream outlet is lower. Each outlet corresponds to a different temperature range, which can adapt to the heating needs of the standby boiler 2 at different stages. The inlet end of each flue gas outlet 5 is connected to the flue of the operating boiler 1, and the outlet end is connected to the main flue gas conveying route 4.

[0037] In some embodiments, each flue gas outlet 5 is equipped with a flue gas outlet fan 6, an isolation baffle, and a flow regulating component 7. The flue gas outlet fan 6 is used to extract flue gas from the flue of the operating boiler 1 through the flue gas outlet 5; the isolation baffle is used to completely cut off the flue gas passage when the corresponding outlet is shut down, preventing air leakage from the flue and interference with the combustion conditions of the operating boiler 1; the flow regulating component 7 can achieve linear opening adjustment from 0% to 100%, used to precisely adjust the flue gas outlet flow rate at the corresponding flue gas outlet 5.

[0038] In this embodiment, multiple outlet points arranged in a tiered manner enable the on-demand use of flue gas at different temperature levels, allowing for adaptation to different hot standby conditions without frequent conditioning, thereby reducing system energy consumption and operational disturbances. Furthermore, the independent on / off switching and flow regulation of individual outlet points enable precise dual control of flue gas outlet volume and outlet flue gas temperature.

[0039] In some embodiments, the main flue gas conveying route 4 is a closed pipeline with a heat insulation structure, connecting all flue gas outlets 5 and the hot standby boiler 2 in series. A booster fan 8 is connected in series on the pipeline. Its core function is to overcome the flow resistance of the long pipeline across the boiler, stabilize the flue gas conveying flow rate, ensure that the flue gas flows in the forward direction from the operating boiler 1 to the hot standby boiler 2, and avoid flue gas stagnation or backflow.

[0040] In some embodiments, the main pipeline of the flue gas conveying unit is located upstream of the flue gas inlet of the hot standby boiler 2, and is divided into two independent, fully sealed conveying branches. The two conveying branches are the furnace conveying branch 9 and the convection flue conveying branch 10. The outlet of the furnace conveying branch 9 is connected to the furnace cavity 3 of the hot standby boiler 2, and is used to send flue gas into the furnace to target and heat the water-cooled wall heating surface. The outlet of the convection flue conveying branch 10 is connected to the convection flue at the tail end of the hot standby boiler 2, and is used to send flue gas into the convection flue to target and heat the superheater and reheater heating surface.

[0041] In some embodiments, the furnace conveying branch 9 and the convection flue conveying branch 10 are respectively provided with electrically operated distribution baffles 11. The distribution baffles 11 can achieve linear opening adjustment from 0 to 100%, which can independently cut off the flue gas passage of the corresponding branch and also precisely adjust the flue gas conveying flow of the corresponding branch.

[0042] In this embodiment, the hot standby boiler 2 can be zoned and targeted for heating by independently adjusting the two branches. It can accurately replenish the temperature of the heating surface with low temperature without increasing the overall flue gas output, thus reducing interference with the operating unit.

[0043] At the same time, it can also adapt to the differentiated needs of different hot standby levels. For example, when it is a first-level hot standby (requiring grid connection within 10 to 30 minutes), the distribution baffle 11 of the furnace conveying branch 9 can be fully opened to prioritize heating the water-cooled wall and greatly improve the boiler start-up speed. When it is a third-level hot standby (requiring grid connection within 4 to 8 hours), the two flue gas flows can be evenly distributed to ensure uniform temperature of the entire heating surface and reduce the risk of low-temperature corrosion.

[0044] In some embodiments, the boiler hot standby maintenance device of this application further includes a flue gas conditioning unit. The flue gas conditioning unit is the core of precise control of flue gas temperature. It is connected in series on the main pipeline of the flue gas conveying unit, located downstream of the flue gas outlet point 5 and upstream of the terminal branch conveying branch. Its core function is to regulate the temperature of the flue gas conveyed to the hot standby boiler 2 to prevent the flue gas temperature from overheating and damaging the heating surface, or from being too low and causing low-temperature corrosion.

[0045] In some embodiments, the flue gas conditioning unit includes a mixing chamber 12, a blending branch 13, and a blending regulating valve 14. One end of the blending branch 13 is connected to the side interface of the mixing chamber 12, and the other end is connected to a cooling medium, which can be one or more of ambient air, low-temperature flue gas from the boiler tail, or return flue gas. The blending regulating valve 14 is an electrically operated linear regulating valve, installed on the blending branch 13, used to precisely control the flow rate of the cooling medium. The mixing chamber 12 is a closed cavity with an internal turbulence structure, connected in series to the main pipeline of the flue gas conveying unit, used to fully and uniformly mix the high-temperature flue gas from the main flue gas conveying pipeline 4 with the cooling medium introduced by the blending branch 13, ensuring a uniform and stable outlet flue gas temperature.

[0046] In some embodiments, the boiler hot standby maintenance device of this application further includes a hot standby controller. The hot standby controller is the control core of the entire device. In this embodiment, a lower-level control module of a power plant distributed control system (DCS) is used, but an independent PLC control cabinet can also be used. The hot standby controller is electrically connected to the isolation baffle, flow regulating component 7, booster fan 8, and distribution baffle 11 of the flue gas conveying unit, the mixing regulating valve 14 of the flue gas conditioning unit, and the local monitoring instruments of the first and second units, respectively, to realize data acquisition, logical operation, and command issuance of the entire system.

[0047] In some embodiments, the hot standby controller collects real-time operating data of the entire system, including: operating data of the first unit, including unit load, flue gas temperature, gas pressure, flue gas oxygen content, and sulfur content of coal entering the furnace; operating data of the second unit, including wall temperature of each heating surface of the hot standby boiler 2, furnace pressure, and furnace humidity; and environmental parameters, including ambient temperature and ambient humidity; providing a data basis for subsequent logical operations.

[0048] In some embodiments, the hot standby controller controls the amount of cooling medium introduced by adjusting the opening of the mixing regulating valve 14, thereby adjusting the temperature of the flue gas delivered to the hot standby boiler 2 after mixing. The core control logic is based on the energy balance formula of the mixing chamber 12, which is: ; Explanation of each physical quantity in the formula: The temperature of the mixed flue gas at the inlet of boiler 2 is for hot standby; The original flue gas flow rate drawn from the selected flue gas outlet point 5 and entering the mixing chamber 12 is expressed in m³ / h. The real-time flue gas temperature at the currently activated target flue gas outlet point 5 is in °C. The flow rate of the cooling medium entering the mixing chamber 12 through the mixing branch 13 is controlled by the opening of the mixing regulating valve 14, and the unit is m³ / h. The real-time temperature of the cooling medium at the inlet of branch 13 is given in °C.

[0049] For example: if the flue gas temperature at the selected outlet is 350℃, the cooling medium is ambient air at 25℃, and the target temperature of the mixed flue gas at the inlet is 200℃, the mixing ratio of the cooling medium and the high-temperature flue gas can be calculated using the above formula. The hot standby controller can accurately control the flow rate of the cooling medium by adjusting the opening of the mixing regulating valve 14, and stably control the mixed flue gas temperature at the target value.

[0050] In this embodiment, the continuous and precise closed-loop regulation of flue gas temperature is achieved through the energy balance formula. This can reduce the flue gas temperature to a safe range for the heated surface when the high-temperature flue gas outlet point 5 is selected, thus avoiding thermal shock. It can also fine-tune the flue gas temperature in real time to ensure that the flue gas temperature is always higher than the minimum inlet flue gas temperature, thereby reducing the risk of low-temperature corrosion.

[0051] In some embodiments, the thermal standby controller has preset multiple thermal standby levels corresponding to the grid-connected startup duration, as well as the target wall temperature range, acid dew point margin, heating strategy, and adjustment parameters corresponding to each thermal standby level. In this embodiment, the thermal standby levels are divided into three levels according to the boiler's grid-connected startup duration: Level 1 hot standby: It can complete the transition from hot standby status to full-load grid-connected power generation within 10 to 30 minutes, corresponding to a target wall temperature range of 280 to 300°C and a matching acid dew point margin of 5 to 10°C. Level 2 hot standby: It can complete the transition from hot standby status to full-load grid-connected power generation within 1 to 2 hours, corresponding to a target wall temperature range of 180 to 200°C and a matching acid dew point margin of 10 to 15°C. Level 3 hot standby, completes the transition from hot standby status to full-load grid-connected power generation within 4 to 8 hours, corresponding to a target wall temperature range of 150 to 170°C and a matching acid dew point margin of 15 to 25°C; The hot standby controller can automatically match the corresponding hot standby level and synchronously update the control parameters of the entire process according to the standby instructions issued by the power grid dispatch.

[0052] In some embodiments, multiple wall temperature measuring points are uniformly arranged along the height direction on the core heating surfaces of the hot standby boiler 2, such as the water-cooled walls, superheaters, and reheaters. Each measuring point is electrically connected to the hot standby controller to collect the wall temperature data of the corresponding heating surface in real time. Based on the target wall temperature range and the real-time wall temperature data, the hot standby controller calculates the heating demand under the current operating conditions using a heat demand index calculation formula, which is: ; Explanation of each physical quantity in the formula: M This represents the total number of wall temperature measuring points installed on the hot standby boiler 2. Let the target wall temperature be at the j-th measuring point. Let the real-time wall temperature be the temperature at the j-th measuring point. is the weight coefficient for the j-th measurement point.

[0053] In this embodiment, by classifying the hot standby level according to the grid connection start-up time, one-click matching of the control parameters of the whole process is achieved, which fits the actual operation requirements of grid peak shaving; by using the weighted summation of the heat demand index, the wall temperature deviation of multiple measuring points is integrated into a single executable control target, avoiding control oscillations caused by local wall temperature deviations, and achieving uniform and stable control of the entire furnace wall temperature.

[0054] In some embodiments, the hot standby controller collects real-time wall temperatures of each heating surface of the hot standby boiler 2 and flue gas temperatures at the boiler inlet at a preset cycle, such as 10 seconds. It simultaneously calculates two core control parameters: one is the deviation of the real-time wall temperature from the target wall temperature range corresponding to the current hot standby level; the other is the difference between the real-time flue gas temperature at the boiler inlet and the lowest inlet flue gas temperature. A positive wall temperature deviation indicates that the wall temperature exceeds the upper limit of the target range, while a negative deviation indicates that the wall temperature is below the lower limit. A positive inlet flue gas temperature difference indicates that the flue gas temperature meets safety constraints, while a negative difference indicates that the flue gas temperature falls below a safety threshold.

[0055] In this embodiment, the wall temperature control requirements and corrosion safety constraints are quantified into actionable control criteria through real-time deviation calculation using two parameters, providing accurate data support for subsequent graded regulation and avoiding control inaccuracies caused by indiscriminate adjustment.

[0056] In some embodiments, the hot standby controller first calculates the flue gas acid dew point temperature based on the collected parameters, and then determines the control threshold of the inlet flue gas temperature using the minimum inlet flue gas temperature calculation formula.

[0057] The formula for calculating the minimum inlet smoke temperature is as follows: ; Explanation of each physical quantity in the formula: The minimum inlet flue gas temperature is the rigid minimum allowable inlet flue gas temperature for the entire operation of the instantaneous standby boiler 2. This is the acid dew point temperature of the flue gas, which is the critical temperature at which sulfuric acid vapor in the flue gas begins to condense. The acid dew point margin is a safe temperature difference set to prevent flue gas temperature from falling below the acid dew point due to fluctuations in operating conditions, and it is matched with the current hot standby level.

[0058] Specifically, the hot standby controller calculates the basic acid dew point temperature based on the collected parameters of sulfur content in the coal entering the furnace of the first unit and ambient humidity. Then, it dynamically corrects the acid dew point temperature by combining the wall temperature and furnace humidity data of the hot standby boiler 2 of the second unit. Finally, it superimposes the matched acid dew point margin to determine the minimum inlet flue gas temperature of the hot standby boiler 2.

[0059] Among them, the minimum inlet flue gas temperature is a rigid minimum temperature constraint for the entire operation of the hot standby boiler 2, and its control priority is always higher than the adjustment priority of the target range of wall temperature. For example, if the sulfur content of the coal entering the first unit is 1%, the calculated flue gas acid dew point temperature is 120℃. If the second unit is a level 3 hot standby unit with a matched acid dew point margin of 20℃, then the final determined minimum inlet flue gas temperature is 140℃, and the hot standby controller must ensure that the boiler inlet flue gas temperature does not fall below 140℃ throughout the entire operation.

[0060] In this embodiment, by using a dynamic acid dew point margin that matches the hot standby level, the technical contradiction in the prior art, where a fixed acid dew point margin cannot simultaneously meet the requirements of rapid start-up and long-term corrosion protection, is resolved. This ensures both the rapid start-up requirements of high-level hot standby and the corrosion protection of long-term hot standby. Furthermore, by setting priorities, the problem of sacrificing corrosion protection for the sake of maintaining wall temperature is avoided.

[0061] In some embodiments, the hot standby controller is preset with a maximum permissible upper limit for the total flue gas flow of the operating boiler 1, which is determined based on the design parameters and operating procedures of the operating boiler 1 or the first unit.

[0062] In some embodiments, the hot standby controller further presets a filtering rule for the flue gas outlet 5, selecting target flue gas outlet 5 that meets all the rules from all flue gas outlet 5. The filtering rule includes: 1. The flue gas temperature at flue gas outlet point 5 shall not be lower than the calculated minimum inlet flue gas temperature, ensuring that the flue gas temperature itself meets the corrosion prevention requirements; 2. The flue gas pressure at flue gas outlet point 5 is greater than the flue gas pressure at the inlet of hot standby boiler 2, ensuring that the flue gas can flow in the forward direction without the need for additional pressurization energy consumption; 3. The total flue gas extraction ratio of all opened flue gas extraction points 5 shall not exceed the maximum allowable limit of the total flue gas flow of the pre-set operating boiler 1, so as to avoid excessive extraction of flue gas and interference with the normal operation and output of the first unit.

[0063] The hot standby controller selects the target flue gas outlet 5 from all flue gas outlet 5 that meets all screening rules, issues a command to open the isolation baffle of the corresponding outlet, and adjusts the opening of the flow regulating component 7 to allow the flue gas to be drawn out from the operating boiler 1; when all flue gas outlet 5 do not meet the screening rules, the flue gas outlet 5 located at the upstream along the flue gas flow direction and with the highest flue gas temperature is selected as the target flue gas outlet 5 and opened. At the same time, the flue gas conditioning unit is started to cool and regulate the flue gas delivered to the hot standby boiler 2 by mixing cooling medium to ensure that the inlet flue gas temperature does not exceed the limit.

[0064] Optionally, the preset filtering rules can be adjusted according to actual working conditions. The preset filtering rules include at least one of the above filtering rules.

[0065] The technical solution in this example realizes intelligent screening of flue gas outlet point 5, giving priority to selecting low-temperature outlet points that meet the requirements, thus reducing the impact on the efficiency of operating boiler 1; through three screening rules, it simultaneously takes into account the three core requirements of corrosion prevention and safety, flow energy consumption, and operating unit stability.

[0066] In some embodiments, the hot standby controller, based on the calculated wall temperature deviation and inlet flue gas temperature difference, progressively adjusts the flue gas output and temperature of the flue gas conveying unit, as well as the flue gas temperature delivered to the hot standby boiler 2 by the flue gas conditioning unit, to achieve progressive closed-loop control of the wall temperature and inlet flue gas temperature, specifically including: When the wall temperature deviation is negative and the absolute value is large (the wall temperature is significantly lower than the lower limit of the target range), and the inlet flue gas temperature difference is positive and the margin is sufficient, the hot standby controller executes a rapid temperature replenishment strategy: significantly increases the flue gas outflow, and simultaneously switches to the upstream high-temperature flue gas outflow point 5 to rapidly raise the wall temperature. When the wall temperature deviation is negative and the absolute value is small (the wall temperature is slightly lower than the lower limit of the target range), and the inlet flue gas temperature difference is positive and the margin is sufficient, the hot standby controller executes a precise fine-tuning strategy: slightly adjust the flue gas outflow, or adjust the distribution baffle 11 to increase the flue gas flow of the furnace conveying branch 9 to avoid wall temperature fluctuations. When the inlet flue gas temperature difference is positive but close to zero (the flue gas temperature is close to the lowest inlet flue gas temperature), regardless of the size of the wall temperature deviation, the safety protection strategy is implemented first: reduce the mixing ratio of the cooling medium to increase the flue gas temperature, or switch to the flue gas outlet point 5 with a higher temperature, so as to always ensure that the inlet flue gas temperature does not fall below the safety threshold. When the wall temperature deviation is positive and exceeds the upper limit, the hot standby controller executes a cooling strategy: reducing the flue gas extraction rate or increasing the mixing ratio of the cooling medium to reduce the flue gas temperature and suppress wall temperature overheating.

[0067] In this embodiment, the refined control of deviation grading solves the industry pain points of wall temperature oscillation and flue gas temperature exceeding the threshold that are easily caused by the traditional single adjustment mode. It not only ensures that the wall temperature reaches the standard quickly, but also always adheres to the corrosion prevention and safety constraints, thereby improving the stability of the system in long-term operation.

[0068] In some embodiments, during the boiler hot standby maintenance phase, the hot standby controller dynamically updates the control commands based on the wall temperature distribution data of each heated surface to maintain the wall temperature of the hot standby boiler 2 within a preset target range. The rules for the hot standby controller to update the control commands include: When the wall temperature of the hot standby boiler 2 is lower than the lower limit of the target wall temperature range, the flue gas outflow is increased, or the opening of the distribution baffle 11 of the furnace conveying branch 9 is increased, and the flue gas conveying flow of the furnace conveying branch 9 is increased to target the water-cooled wall of the furnace and quickly raise the wall temperature. When the real-time flue gas temperature at the inlet of the hot standby boiler 2 is lower than the minimum inlet flue gas temperature, the opening of the mixing regulating valve 14 is reduced, the mixing ratio of the cooling medium is decreased, and the flue gas temperature is increased. Alternatively, the currently open flue gas outlet 5 is closed, and the upstream flue gas outlet 5 with a higher flue gas temperature is opened to increase the flue gas temperature from the source. When the wall temperature of the hot standby boiler 2 is higher than the upper limit of the target wall temperature range, reduce the flue gas outflow, or increase the opening of the mixing regulating valve 14 to increase the mixing ratio of the cooling medium, thereby reducing the flue gas temperature and suppressing wall temperature overheating.

[0069] The technical solution in this example achieves multi-dimensional closed-loop regulation. It does not rely on additional heating energy and can achieve stable wall temperature control simply by adjusting the flue gas flow rate, temperature, and flow path. At the same time, by using zoned targeted heating, it further reduces interference to the operating unit and improves waste heat utilization efficiency.

[0070] In some embodiments, the boiler hot standby maintenance device of this application further includes a safety interlock protection unit. The safety interlock protection unit is the inherent safety guarantee of the entire device. It is electrically connected to the hot standby controller, and its core function is to prevent safety risks such as backflow, leakage, deflagration, and overpressure during the cross-furnace flue gas transportation process, thus constructing a full-process safety protection system.

[0071] The safety interlock protection unit includes a series double isolation baffle, a check valve, a purge circuit, and a pressure relief assembly. The specific structure and function of each component include: The series of double isolation baffles are connected in series along the flue gas flow direction at the flue gas outlet of the flue gas conveying unit, located downstream of all flue gas outlet points 5 and upstream of the flue gas conditioning unit. A sealed leak detection chamber is set between the two baffles. This is used to achieve double physical isolation when the system is shut down or interlock is triggered, completely cutting off the flue gas passage between the operating boiler 1 and the flue gas conveying unit, and preventing the risk of high-temperature flue gas leakage and backflow.

[0072] The check valve is connected in series on the main pipeline of the flue gas conveying unit, located downstream of the series double isolation baffle. Its opening direction is completely consistent with the forward conveying direction of the flue gas. It is used to structurally block the reverse flow of flue gas from the hot standby boiler 2 side to the operating boiler 1 side, forming a double redundancy protection against backflow with the series double isolation baffle.

[0073] The purging circuit is connected to the sealed chamber between the series double isolation baffles and the upstream and downstream ends of the flue gas conveying main pipeline. It is equipped with electromagnetic control valves and inert gas sources. It is used to purge the entire pipeline with inert gas before the system is put into operation, after it is shut down, or when the interlock is triggered. This removes the combustible gas, air and residual acidic flue gas accumulated in the pipeline, and prevents the risk of deflagration and pipeline corrosion from the source.

[0074] The pressure relief assembly uses a quick-opening pressure relief valve with pressure monitoring, which is located at the end of the flue gas conveying unit and upstream of the flue gas inlet of the hot standby boiler 2. It is used to quickly open and relieve pressure when the pipeline pressure exceeds the preset threshold, preventing the risk of pipeline overpressure damage and flue gas impacting the heating surface of the hot standby boiler 2.

[0075] In some embodiments, the hot standby controller is preset with interlocking trigger conditions. When any condition is met, the emergency response process is immediately triggered. The interlocking trigger conditions include: the risk of backflow due to reverse pressure difference across the furnace, the oxygen or combustible gas content in the flue gas exceeding the limit, the pipeline pressure exceeding the threshold, the inlet flue gas temperature exceeding the safe range, and the abnormal position feedback of the actuator. The emergency response process includes: cutting off the series double isolation baffle, opening the pressure relief component, and starting the purging circuit for inerting purging.

[0076] The technical solution in this real-time example constructs a four-level intrinsically safe protection system of "source isolation, pipeline backflow prevention, full-process inertization, and end-point pressure relief". It transforms various safety risks of cross-furnace flue gas transportation into interlocking actions that can be monitored and automatically handled, ensuring long-term stable operation of the system and reducing on-site safety management costs.

[0077] This application also provides a boiler hot standby maintenance control method, implemented based on the aforementioned boiler hot standby maintenance device. The main body executing the method is the hot standby controller. The structural details, calculation formulas, and parameter logic of the device have been described in detail in the embodiments, and will not be repeated in this embodiment. Only the entire process of the method will be summarized. Figure 2 As shown, the specific steps include the following: Match the corresponding hot standby level according to the power grid dispatch instructions, preset the target range of hot standby boiler wall temperature and acid dew point margin that match the hot standby level; collect real-time operating data and environmental parameters of the first unit and the second unit in real time; Based on the collected operating data and environmental parameters, the flue gas acid dew point temperature is obtained through the acid dew point calculation formula. The matching acid dew point margin is superimposed to generate the minimum inlet flue gas temperature of the hot standby boiler. The minimum inlet flue gas temperature is set as a rigid constraint for the entire process, and its control priority is higher than that of the wall temperature regulation priority. Based on preset screening rules, a target flue gas outlet is selected from multiple flue gas outlets and activated; if no outlet meets the screening rules, the upstream high-temperature flue gas outlet is activated and the flue gas conditioning unit is started simultaneously, and cooling control is performed based on the mixing chamber energy balance formula. Calculate the deviation of the real-time wall temperature from the target wall temperature range and the difference between the inlet flue gas temperature and the minimum inlet flue gas temperature. Based on the magnitude of the deviation and the difference, adjust the flue gas outflow, flue gas temperature and flow path distribution in stages. Under the constraint that the inlet flue gas temperature of the hot standby boiler is not lower than the minimum inlet flue gas temperature, the wall temperature of the hot standby boiler is stably maintained within the preset target wall temperature range. Real-time monitoring of preset interlocking trigger conditions; when any interlocking trigger condition is met, an emergency response procedure is immediately triggered to ensure system and equipment safety. Upon receiving the start-up command for the second unit, or when the operating conditions of the first unit change and it becomes unsuitable to continue supplying heat, the heating intensity is smoothly reduced according to a preset slope to constrain the rate of change of wall temperature and flue gas temperature and avoid thermal shock. The entire pipeline exit purging process is executed, and at the same time, thermal maintenance status parameters are output, including key wall temperature data, acid dew point margin records, equipment operating status, etc., to guide the rapid ignition and start-up and heating and pressurization operations of the hot standby boiler.

[0078] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be covered. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A boiler hot standby maintenance device, comprising a first unit with operating active power output and a second unit in hot standby state, wherein the first unit is equipped with an operating boiler and the second unit is equipped with a hot standby boiler, characterized in that, Also includes: Flue gas conveying unit: Connects the operating boiler and the hot standby boiler. The flue gas conveying unit has multiple flue gas outlets along the flue gas flow direction of the operating boiler flue. The flue gas temperature drawn from each of the flue gas outlets corresponds to a different temperature range. The flue gas conveying unit is used to draw flue gas from the operating boiler and convey the flue gas to the hot standby boiler. By adjusting the opening and closing of each flue gas outlet and the flue gas flow rate, the amount of flue gas drawn out and the temperature of the drawn-out flue gas are controlled. Flue gas conditioning unit: installed on the pipeline of the flue gas conveying unit, used to regulate the temperature of the flue gas conveyed to the hot standby boiler; Hot standby controller: electrically connected to the flue gas conveying unit, flue gas conditioning unit, first unit and second unit respectively; The hot standby controller is configured as follows: The target range of wall temperature for the hot standby boiler is preset; real-time operating data and environmental parameters of the first and second units are collected, and the minimum inlet flue gas temperature of the hot standby boiler is determined based on the collected data; The operation of the flue gas conveying unit and the flue gas conditioning unit is regulated to maintain the wall temperature of the hot standby boiler within the target range, under the constraint that the flue gas temperature at the inlet of the hot standby boiler is not lower than the minimum inlet flue gas temperature.

2. The boiler thermal standby maintenance device according to claim 1, characterized in that, The hot standby controller is configured as follows: The preset screening rules for flue gas outlet points include at least one of the following rules: the flue gas temperature at the outlet point is not lower than the minimum inlet flue gas temperature; the flue gas pressure at the outlet point is greater than the flue gas pressure at the inlet of the hot standby boiler. The total flue gas outflow ratio of all opened flue gas outlets shall not exceed the preset maximum allowable limit of the total flue gas flow of the operating boiler. Select the target flue gas outlet point that meets the screening rules from all flue gas outlet points, and open the target flue gas outlet point to draw the flue gas out from the operating boiler. If none of the flue gas outlets meet the screening rules, select the flue gas outlet located at the upstream end along the flue gas flow direction as the target flue gas outlet, and start the flue gas conditioning unit to cool down the flue gas temperature delivered to the hot standby boiler.

3. The boiler thermal standby maintenance device according to claim 1, characterized in that, The flue gas conditioning unit includes a mixing chamber, a blending branch, and a blending regulating valve. One end of the mixing branch is connected to the mixing chamber, and the other end is connected to the cooling medium. The mixing regulating valve is installed on the mixing branch. The mixing chamber is connected in series with the main pipeline of the flue gas conveying unit and is used to mix the flue gas of the flue gas conveying unit with the cooling medium introduced by the mixing branch. The hot standby controller controls the amount of cold-end medium introduced by adjusting the opening of the mixing regulating valve, thereby regulating the temperature of the flue gas delivered to the hot standby boiler.

4. The boiler thermal standby maintenance device according to claim 3, characterized in that, The main pipeline of the flue gas conveying unit is divided into a furnace conveying branch and a convection flue conveying branch upstream of the flue gas inlet of the hot standby boiler. The outlet of the furnace conveying branch is connected to the furnace cavity of the hot standby boiler, and the outlet of the convection flue conveying branch is connected to the convection flue at the tail of the hot standby boiler. Distribution baffles are respectively installed on the furnace conveying branch and the convection flue conveying branch. The distribution baffles are used to cut off the flue gas passage of the furnace conveying branch and the convection flue conveying branch, and to regulate the flue gas conveying flow of the furnace conveying branch and the convection flue conveying branch.

5. The boiler thermal standby maintenance device according to claim 4, characterized in that, The hot standby controller is configured to dynamically update control commands during the boiler hot standby maintenance phase to maintain the wall temperature of the hot standby boiler within a preset target range. The rules for updating the control commands of the hot standby controller include: When the wall temperature of the hot standby boiler is lower than the lower limit of the target wall temperature range, increase the flue gas outflow or increase the flue gas conveying flow rate of the furnace conveying branch. When the flue gas temperature at the inlet of the hot standby boiler is lower than the minimum inlet flue gas temperature, the mixing ratio of the cooling medium is reduced, or the currently open flue gas outlet is closed and the upstream flue gas outlet is opened. When the wall temperature of the hot standby boiler is higher than the upper limit of the target wall temperature range, reduce the flue gas extraction rate or increase the mixing ratio of the cooling medium.

6. The boiler thermal standby maintenance device according to claim 1, characterized in that, The flue gas outlet is equipped with an isolation baffle and a flow regulating component. The isolation baffle is used to cut off the flue gas passage at the corresponding flue gas outlet, and the flow regulating component is used to regulate the flue gas outlet flow rate at the corresponding staged flue gas outlet.

7. The boiler thermal standby maintenance device according to claim 1, characterized in that, It also includes a safety interlock protection unit, which includes a series double isolation baffle, a check structure, a purge circuit and a pressure relief assembly; The series double isolation baffle is installed at the flue gas outlet of the flue gas conveying unit to cut off the flue gas passage between the operating boiler and the flue gas conveying unit. The check valve structure is installed on the pipeline of the flue gas conveying unit to block the reverse flow of flue gas from the hot standby boiler side to the operating boiler side. The purging circuit is connected to the pipeline of the flue gas conveying unit. By introducing inert gas into the pipeline of the flue gas conveying unit, the combustible gas and acidic flue gas accumulated in the pipeline are removed. The pressure relief assembly is located at the end of the flue gas conveying unit, upstream of the flue gas inlet of the hot standby boiler, and is used to discharge the flue gas in the pipeline when the pipeline is over-pressurized.

8. The boiler thermal standby maintenance device according to claim 1, characterized in that, The hot standby controller is configured as follows: Multiple preset thermal standby levels are provided, corresponding to grid-connected startup duration, along with target wall temperature ranges for each thermal standby level. The wall temperature and inlet flue gas temperature of the hot standby boiler are collected in real time, and the deviation of the real-time wall temperature from the target wall temperature range and the difference of the inlet flue gas temperature from the lowest inlet flue gas temperature are calculated. Based on the magnitude of the deviation and difference, the flue gas output and temperature of the flue gas conveying unit are adjusted, as are the flue gas temperature of the flue gas delivered to the hot standby boiler by the flue gas conditioning unit.

9. The boiler thermal standby maintenance device according to any one of claims 1-8, characterized in that, The hot standby controller is configured as follows: Acid dew point margin pre-set to match the hot standby level of the second unit; Based on the sulfur content of the coal fed into the first unit, the humidity parameters of the environment where the unit is located, and the wall temperature and humidity data of the hot standby boiler of the second unit, the acid dew point temperature of the flue gas of the hot standby boiler is calculated. The minimum inlet flue gas temperature is determined based on the flue gas acid dew point temperature and acid dew point margin.

10. A boiler hot standby maintenance control method, characterized in that, The method is implemented based on the boiler thermal standby maintenance device according to any one of claims 1-9, wherein the method is controlled and executed by a thermal standby controller, and includes: Preset the target range for the wall temperature of the hot standby boiler; Collect real-time operating data and environmental parameters of the first and second units, and determine the minimum inlet flue gas temperature of the hot standby boiler based on the collected data; Adjust the flue gas outflow and the flue gas temperature delivered to the hot standby boiler, and maintain the wall temperature of the hot standby boiler within the target wall temperature range, while ensuring that the flue gas temperature at the inlet of the hot standby boiler is not lower than the minimum inlet flue gas temperature.

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