A method and system for measuring and calculating the real-time calorific value of coal entering an ammonia-doped boiler

Abstract

The present application relates to the field of coal-fired power generation technology, and more particularly to a method and system for real-time calorific value measurement of coal fed into an ammonia-doped boiler. The technical solution comprises the following steps: determination of coal feed adjustment lag time window; data collection under ammonia-doping conditions; thermal inertia compensation calculation; real-time calorific value calculation of coal fed into the boiler; and calorific value data verification and updating. The present application precisely defines the coal feed adjustment lag time window to avoid fluctuations in coal feed, and combines a thermal inertia compensation model to eliminate the influence of boiler thermal inertia on power monitoring, thereby achieving online real-time measurement of the calorific value of coal fed into the boiler. The present application breaks through the lag problem of traditional offline sampling analysis, ensures accurate measurement results and strong timeliness of historical benchmark values, improves energy utilization efficiency, and helps power plants reduce costs and increase efficiency.

Description

Technical Field

[0001] This invention relates to the field of coal-fired power generation technology, and in particular to a method and system for real-time calculation of the calorific value of coal fed into an ammonia-blended boiler. Background Technology

[0002] In coal-fired power generation, accurately and timely determining the real-time calorific value of the coal fed into the furnace is crucial for the efficient and stable operation of the boiler, optimized combustion control, energy conservation and emission reduction, and the economical dispatch of the power plant. The calorific value of the coal fed into the furnace is a core parameter for fuel blending, load allocation, efficiency calculation, and pollutant control.

[0003] Currently, the measurement of the calorific value of coal fed into the boiler mainly relies on offline sampling and testing methods. This involves periodically collecting coal samples from the conveyor belt or coal bunker and sending them to a laboratory for industrial analysis, ultimately measuring the calorific value using equipment such as an oxygen bomb calorimeter. While this method offers high accuracy, it suffers from significant lag, typically requiring several hours or even longer to obtain results. However, in actual production, the calorific value of coal fed into the boiler can fluctuate frequently due to factors such as coal source switching and uneven coal blending. The severe lag in offline testing means it cannot reflect the true quality of the coal currently fed into the boiler in real time. This makes it difficult for operators to adjust key operating parameters such as the air-coal ratio in a timely manner based on changes in the calorific value of the coal fed into the boiler. This not only affects boiler combustion efficiency but may also lead to equipment failures, hindering the improvement of power plant operation optimization.

[0004] The coal-fired power generation industry faces severe pressure to reduce carbon emissions. Ammonia-blended combustion technology, because its fuel ammonia (NH3) contains no carbon, can effectively reduce or even replace some of the carbon dioxide emissions from coal combustion, and has become one of the important technological pathways for coal-fired power plants to achieve low-carbon transformation. Currently, several power plants in China have completed the retrofitting of their boiler ammonia-blended combustion systems, achieving the co-combustion of ammonia and coal.

[0005] However, existing online technologies or estimation models for real-time calorific value calculation of coal fed into the boiler mostly require simultaneous access to multiple parameters such as boiler load, flue gas composition, and coal quality industrial analysis data, resulting in high operational complexity and strong dependence on data acquisition systems. Furthermore, for power plants that have completed ammonia-blended combustion retrofits, existing methods for calculating the real-time calorific value of coal fed into the boiler have not fully incorporated the process characteristics of "ammonia-coal co-combustion" into their design schemes. Therefore, this application proposes a method and system for calculating the real-time calorific value of coal fed into ammonia-blended boilers. For power plants that have implemented ammonia-blended combustion retrofits, under load fluctuations, by adjusting the ammonia blending process, only a small amount of readily available online monitoring data is needed to quickly and accurately calculate the real-time calorific value of coal fed into the boiler, providing a suitable technical solution for dynamic coal quality monitoring and combustion optimization in ammonia-blended combustion power plants. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method and system for calculating the real-time calorific value of coal fed into an ammonia-blended boiler, which can make full use of the ammonia-blended retrofit system of the power plant to quickly and accurately calculate the real-time calorific value of the coal fed into the boiler.

[0007] In a first aspect, the present invention provides a method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler, comprising the following steps:

[0008] The coal feed rate regulation lag time window is determined by monitoring the completion time of steam valve regulation and the start time of coal feed rate control signal response before and after the power grid load dispatch command is triggered.

[0009] Ammonia blending operation data acquisition: During the coal feed rate adjustment lag time window, ammonia blending combustion is carried out, and real-time operating data including boiler monitoring power generation, total coal consumption per unit time, and total ammonia consumption per unit time are collected simultaneously.

[0010] Thermal inertia compensation calculation: Based on the boiler's monitored power generation, dynamic compensation is performed according to the thermal inertia compensation model to calculate the boiler's real-time power generation after eliminating the influence of thermal inertia.

[0011] The real-time calorific value of the coal fed into the furnace is calculated based on the real-time power generation of the boiler, the total coal consumption per unit time, and the total ammonia consumption per unit time, using a calorific value calculation model.

[0012] The calorific value data is verified and updated by comparing the real-time calorific value of the coal fed into the furnace with the historical benchmark value. Based on the comparison result and the preset threshold for updating the calorific value of the coal fed into the furnace, it is determined whether to update the historical benchmark value.

[0013] Optionally, the step of determining the lag time window for coal feed rate adjustment specifically includes:

[0014] Before receiving the power grid load adjustment command, record the initial stable value F0 of the coal feed control signal before the load adjustment command; after receiving the power grid load adjustment command, monitor the steam valve opening, main steam pressure and main steam flow, and record time t1 when all three meet the preset stability conditions.

[0015] The moment t2 when the coal feed rate control signal first deviates from F0 is monitored;

[0016] The coal feed rate adjustment lag time window is [t1, t2]; wherein, the preset stability conditions include no change in the steam valve opening for more than 3 consecutive seconds, main steam pressure fluctuation amplitude ≤0.2MPa and main steam flow fluctuation amplitude ≤2%.

[0017] Optionally, the validity of the coal feed rate adjustment lag time window [t1, t2] is also verified: if the time difference between t2 and t1 is not greater than 30 seconds, the window is determined to be invalid and the current calorific value calculation is cancelled.

[0018] Optionally, in the ammonia blending operation data acquisition, the real-time operating data needs to be filtered to remove high-frequency noise.

[0019] Optionally, in the thermal inertia compensation calculation step, the thermal inertia compensation model is:

[0020]

[0021] in, The real-time power generation of the boiler, calculated using the thermal inertia compensation model, is expressed in MW. The boiler monitoring power output displayed on the distributed control system panel is in MW; T is the boiler thermal inertia time constant in seconds, which is obtained through boiler thermodynamic characteristic experiments. The rate of change in boiler power generation is measured in MW / s.

[0022] Optionally, the boiler monitors the rate of change in power generation. Calculated in the following way:

[0023]

[0024] in, The time superimposed after the start of ammonia-blended combustion is called the pure time delay. The determined pure time delay, for Real-time boiler power generation monitoring; This refers to a monitoring point within a dynamic upward phase, satisfying T / 10 ≤ ≤T / 20, for The boiler power generation is monitored at any given time; the pure delay time τ and the dynamic rise stage are calibrated through boiler thermodynamic characteristic tests.

[0025] Optionally, the calculation time window [t] for the boiler monitoring power generation change rate... τ The value of t] must fall entirely within the coal feed rate adjustment lag time window [t1, t2].

[0026] Optionally, in the real-time calorific value estimation of the coal fed into the furnace, the calorific value calculation model is as follows:

[0027] ,

[0028] in, This indicates the real-time calorific value of the coal fed into the furnace, in MJ / kg. The boiler power generation efficiency needs to be calibrated using boiler design parameters or historical operating data. This indicates the total ammonia consumption of the boiler per unit time, expressed in kg / s. The lower heating value of ammonia is expressed as 18.6 MJ / kg; This indicates the total coal consumption of the boiler per unit time, expressed in kg / s.

[0029] Optionally, in the calorific value data verification and update step, the historical benchmark value The initial value is the calorific value of the coal fed into the furnace, based on the coal quality test report. Subsequent values ​​are the most recently calculated and stored real-time calorific value of the coal fed into the furnace. In the comparison step, the real-time calorific value of the coal fed into the furnace is determined. Compared with the historical benchmark value Whether the absolute value of the difference exceeds the preset threshold for updating the calorific value of the coal fed into the furnace, wherein the preset threshold for updating the calorific value of the coal fed into the furnace is set according to the characteristics of the coal type.

[0030] In a second aspect, the present invention provides a system for real-time calculation of the calorific value of coal fed into an ammonia-blended boiler to implement the method described in the first aspect, comprising:

[0031] The coal feed rate regulation lag window determination module is used to receive the grid load dispatching command, record the stable initial value of the coal feed rate control signal, and collect the steam valve opening, main steam pressure and main steam flow. By judging the time when the steam valve opening, main steam pressure and main steam flow meet the preset stable conditions, and the time when the coal feed rate control signal first deviates from the stable initial value, the coal feed rate regulation lag time window is determined.

[0032] The ammonia blending operation data acquisition module is connected to the coal feed rate adjustment lag window determination module. It is used to trigger the ammonia burner to perform ammonia blending combustion within the coal feed rate adjustment lag time window, and synchronously acquire real-time operating data of boiler monitoring power generation, total coal consumption per unit time, and total ammonia consumption per unit time through the distributed control system.

[0033] The thermal inertia compensation power calculation module is connected to the ammonia-blended operating condition data acquisition module. It is used to call the boiler monitoring power generation data output by the ammonia-blended operating condition data acquisition module, substitute it into the thermal inertia compensation model, and calculate the compensated real-time power generation of the boiler.

[0034] The real-time calorific value calculation module for coal fed into the furnace is connected to the ammonia-blended operating condition data acquisition module and the thermal inertia compensation power calculation module. It is used to call the total coal consumption per unit time and the total ammonia consumption per unit time data output by the ammonia-blended operating condition data acquisition module and the real-time power generation data of the boiler output by the thermal inertia compensation power calculation module, and substitute them into the calorific value calculation model to calculate the real-time calorific value of the coal fed into the furnace.

[0035] The calorific value data verification and update module is connected to the real-time calorific value calculation module for coal fed into the furnace. It is used to call the real-time calorific value of coal fed into the furnace output by the real-time calorific value calculation module for coal fed into the furnace and compare it with the historical benchmark value of calorific value of coal fed into the furnace. Based on the relationship between the difference and the preset threshold for updating the calorific value of coal fed into the furnace, it triggers the real-time calorific value database update or maintains the historical benchmark value and outputs instructions to the boiler control system.

[0036] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0037] This invention utilizes a specific time window during load adjustment for online calculations, enabling rapid results within minutes and achieving real-time measurement. The method eliminates the power indication delay caused by the boiler's large heat capacity through a thermal inertia compensation model, ensuring that the power data used in the calculation more accurately reflects the instantaneous energy input and thus guaranteeing the accuracy of the final calorific value.

[0038] The measurement timing of this invention is chosen to be during a window period when the coal feed rate has not changed and the power is only fine-tuned by adding ammonia. This design ensures that the quality of the coal entering the furnace remains constant during the measurement period, actively isolating the largest source of interference. At the same time, introducing ammonia as a known and accurately measurable "standard energy source" into the system provides a stable and reliable benchmark for calculating the real-time calorific value of the coal entering the furnace based on the principle of energy conservation.

[0039] This invention automates the entire process through a modular system, automatically capturing operating conditions, collecting data, calculating, and verifying and updating calorific values ​​without manual intervention. This not only reduces workload but also ensures data continuity and objectivity. The obtained real-time calorific value data can be directly used to guide the boiler combustion optimization control system, thereby improving boiler combustion efficiency.

[0040] This invention directly relies on the existing ammonia-blended combustion retrofit system in power plants. It provides a proprietary solution to address new measurement challenges arising after low-carbon retrofitting, and strongly supports the safe, stable, and efficient application of ammonia-blended combustion technology.

[0041] This invention avoids interference from coal feed fluctuations by precisely defining the lag time window for coal feed adjustment, and eliminates the impact of boiler thermal inertia on power monitoring by combining a thermal inertia compensation model. It achieves online real-time calculation of the calorific value of the coal fed into the furnace, overcoming the lag problem of traditional offline sampling analysis. At the same time, it constructs a closed-loop data management mechanism through a calorific value data verification and update module to ensure accurate calculation results and strong timeliness of historical benchmark values. This not only provides real-time data support for boiler combustion optimization and load matching, reducing coal waste and improving energy utilization efficiency, but also accumulates calorific value data under multiple operating conditions, providing a basis for power plant fuel procurement and inventory management, and helping power plants reduce costs and increase efficiency. Attached Figure Description

[0042] Figure 1 A flowchart illustrating a method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler;

[0043] Figure 2 The flowchart for thermal inertia compensation calculation;

[0044] Figure 3 This is a schematic diagram of a system for calculating the real-time calorific value of coal fed into an ammonia-blended boiler. Detailed Implementation

[0045] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0046] Example

[0047] See Figure 1 This application provides a method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler, comprising the following steps:

[0048] Step 101: Before receiving the power grid load adjustment command, record the stable initial value of the current coal feed control signal, denoted as F0. After receiving the power grid load adjustment command, collect the steam valve opening, main steam pressure, and main steam flow in real time through the distributed control system. When the steam valve opening, main steam pressure, and main steam flow all meet the preset stable conditions, determine that the steam valve adjustment is complete, and record this moment as t1. Continuously monitor the coal feed control signal through the distributed control system. When the coal feed control signal deviates from F0 for the first time, record this moment as t2. Define the time window [t1, t2] as the coal feed adjustment lag time window, with t1 as the starting point and t2 as the ending point.

[0049] In some embodiments, the preset stable conditions for steam valve opening, main steam pressure and main steam flow are that the steam valve opening remains unchanged for more than 3 seconds, the main steam pressure fluctuation is ≤0.2MPa and the main steam flow fluctuation is ≤2%.

[0050] In some embodiments, the control signal for the coal feeder is the speed of the coal feeder. The speed of all coal feeders is continuously monitored by a distributed control system. When the speed of any coal feeder changes and deviates from F0, it is time t2.

[0051] In some embodiments, when the time difference between t2 and t1 is not greater than 30 seconds, the coal feed rate adjustment lag time window is determined to be an invalid window, and the calculation of the real-time calorific value of the coal fed into the furnace during this load adjustment is cancelled.

[0052] In this embodiment, the time difference between steam valve adjustment and coal feed rate change after grid load adjustment was accurately captured. By recording the stable initial value of the coal feed rate control signal, determining the completion time of steam valve adjustment, and the first deviation time of coal feed rate, the lag time window for coal feed rate adjustment was clarified. The determination of this window provides a key time boundary for subsequent ammonia-blended combustion experiments during the period when the coal feed rate does not change, effectively avoiding the interference of coal feed rate fluctuations on subsequent data acquisition and calorific value calculation.

[0053] Step 102: Within the coal feed rate adjustment lag time window, ammonia-blended combustion is carried out through the ammonia burner, and real-time boiler operation data under ammonia-blended conditions is synchronously collected through the distributed control system. The real-time boiler operation data includes the boiler's monitored power generation, total coal consumption per unit time, and total ammonia consumption per unit time.

[0054] The boiler's power generation is the power generation displayed on the dashboard of the distributed control system.

[0055] The boiler's real-time operating data needs to be filtered by the distributed control system to remove high-frequency noise interference and ensure the accuracy of subsequent calculations.

[0056] In some embodiments, the ammonia blending ratio needs to be determined based on the boiler load level before the load adjustment command. When collecting real-time boiler operating data through a distributed control system, the real-time operating data needs to be filtered to remove high-frequency noise.

[0057] The boiler's power generation is monitored by acquiring electrical signals through the generator protection device and transmitting them to the distributed control system at a certain frequency. The total coal consumption of the boiler per unit time includes the sum of the coal feeders of all coal feeders. The total ammonia consumption of the boiler per unit time is calculated by superimposing data from flow meters installed before all ammonia burners.

[0058] It is worth noting that performing ammonia-blended combustion and collecting data within the coal feed rate adjustment lag time window determined in step 101 makes full use of the power plant's existing ammonia-blending retrofit system, eliminating the need for additional complex experimental equipment, reducing calculation costs and implementation difficulty, and meeting the technical application requirements after the power plant's low-carbon retrofit. On the other hand, by synchronously collecting boiler monitoring power generation, total coal consumption per unit time, and total ammonia consumption per unit time through the distributed control system, the collected data comes directly from the power plant's daily operation monitoring system, ensuring strong data authenticity and real-time performance.

[0059] Step 103: Based on the boiler's monitored power generation, dynamic compensation is performed according to the thermal inertia compensation model to calculate the boiler's real-time power generation after eliminating the influence of thermal inertia.

[0060] See Figure 2 Step 103 includes the following steps:

[0061] Step 1031, determine the time constant T:

[0062] The time constant T is determined through boiler thermodynamic characteristic test calibration. In some embodiments, based on the boiler's heat capacity characteristics, the time constant T is determined by measuring the time required for the system output to reach 63.2% of the steady-state value through a step response experiment, with the unit being seconds. The time constant T reflects the magnitude of the boiler's thermal inertia.

[0063] Step 1032, determine the pure time delay. :

[0064] Pure time delay refers to the time delay between a change in the input and the start of a response in the output signal of the boiler system. In this embodiment, the input change refers to ammonia-blended combustion in the boiler, and the output signal refers to the boiler's monitored power generation displayed on the distributed control system panel. Pure time delay can be calibrated through boiler thermodynamic characteristic tests.

[0065] Step 1033, determine the pure time delay. :

[0066] Pure delay time The initial moment of the ammonia doping change is superimposed with the pure time delay. After The time is the starting point at which the boiler's power generation begins to respond to changes in ammonia addition. In some embodiments, the time when the boiler begins adding ammonia is denoted as... Then the pure time delay ;

[0067] Step 1034: Determine the monitoring time during the dynamic rising phase. :

[0068] The dynamic upward phase refers to the phase from the pure lag time. The monitoring period from the start of the monitoring until the boiler's power generation reaches a stable state; the monitoring time during the dynamic upward phase. The Shannon sampling theorem must be satisfied, i.e., T / 10 ≤ - ≤T / 20.

[0069] In some embodiments, the boiler monitoring power generation entering a stable state means that the fluctuation range of the boiler monitoring power generation is ≤1%.

[0070] Step 1035: Perform thermal inertia compensation calculations based on the thermal inertia compensation model. The thermal inertia compensation model is as follows:

[0071]

[0072] in, The real-time power generation of the boiler, calculated using the thermal inertia compensation model, is expressed in MW. The boiler monitoring power output displayed on the distributed control system panel is in MW; T is the boiler thermal inertia time constant in seconds, which is obtained through boiler thermodynamic characteristic experiments. The rate of change of boiler power generation is measured in MW / s and is calculated using the following formula:

[0073]

[0074] In the formula, Monitoring time during the dynamic upward phase after the change in ammonia dosage. Boiler power generation monitoring The pure lag time after the change in ammonia dosage The boiler's power generation capacity is monitored.

[0075] The time window for calculating the rate of change in boiler power generation [t] τ The value of t] must fall entirely within the coal feed rate adjustment lag time window [t1, t2] to avoid interference from changes in coal feed rate on power monitoring.

[0076] As a complex thermal system, a boiler exhibits significant thermal inertia, meaning its monitored power generation cannot reflect the actual energy output in real time, severely impacting the accuracy of calorific value calculations. This step addresses this by establishing a thermal inertia compensation model, incorporating the boiler's thermal inertia time constant and the rate of change of power generation, to compensate and correct the monitored power generation collected by the distributed control system. This effectively eliminates the interference of thermal inertia on power monitoring, making the calculated compensated real-time boiler power generation closer to the boiler's actual energy output level. Furthermore, the clear definition of pure time lag, dynamic rise phase, and monitoring time within the model further standardizes the conditions for compensation calculations.

[0077] Step 104: Calculate the real-time calorific value of the coal fed into the furnace based on the calorific value calculation model.

[0078] The calorific value calculation model is as follows:

[0079] ,

[0080] in, This indicates the real-time calorific value of the coal fed into the furnace, expressed in MJ / kg. The boiler power generation efficiency needs to be calibrated using boiler design parameters or historical operating data. This indicates the total ammonia consumption of the boiler per unit time, expressed in kg / s. The lower heating value of ammonia is generally taken as 18.6 MJ / kg; This indicates the total coal consumption of the boiler per unit time, expressed in kg / s.

[0081] In this embodiment, a calorific value calculation model is constructed based on the energy balance principle. This model incorporates parameters such as the compensated real-time boiler power generation, boiler power generation efficiency, total ammonia consumption per unit time, total coal consumption per unit time, and the lower heating value of ammonia, directly calculating the real-time calorific value of the coal fed into the boiler. Compared to traditional offline sampling and analysis methods, this calculation method eliminates the need to wait for laboratory test results, enabling online real-time measurement of the calorific value of the coal fed into the boiler. It can quickly reflect changes in the calorific value of the coal fed into the boiler, providing data support for power plants to adjust their combustion strategies in a timely manner. Furthermore, the model parameters are mostly derived from known design parameters or real-time collected data from the power plant, with clear calculation logic and strong operability. The calculation results can directly serve boiler combustion optimization, helping to improve energy utilization efficiency.

[0082] Step 105: Calculate the real-time calorific value of the coal fed into the furnace. Compared with the historical benchmark value of calorific value of coal fed into the furnace The comparison is performed. If the absolute value of the difference exceeds the preset threshold for updating the calorific value of the coal fed into the furnace, the real-time calorific value database of the coal fed into the furnace is updated. Store as If the absolute value of the difference does not exceed the preset threshold for updating the calorific value of the coal fed into the furnace, the historical benchmark value will be maintained. constant.

[0083] In some embodiments, when the real-time calorific value of the coal fed into the furnace is calculated... When calculating the effective value based on the load change window for the first time after the start-up of a coal-fired boiler system or after a change in the type of coal fed into the boiler, the calorific value of the coal quality test report is used as the historical benchmark value of the calorific value of the coal fed into the boiler. When the real-time calorific value of the coal fed into the furnace is calculated in this test... For values ​​not calculated for the first time, the historical baseline value of the calorific value of the coal fed into the furnace is the most recently calculated and stored value based on the load change window. .

[0084] The preset threshold for updating the calorific value of the coal fed into the furnace needs to be calibrated based on the characteristics of the coal type. In some embodiments, when the coal fed into the furnace is lignite, the preset threshold for updating the calorific value of the coal fed into the furnace is set to 2 MJ / kg; when the coal fed into the furnace is bituminous coal, the preset threshold for updating the calorific value of the coal fed into the furnace is set to 1.5 MJ / kg; and when the coal fed into the furnace is anthracite, the preset threshold for updating the calorific value of the coal fed into the furnace is set to 1 MJ / kg. The preset threshold for updating the calorific value of the coal fed into the furnace can be adjusted through a human-computer interaction interface.

[0085] In some embodiments, a method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler includes an adaptive adjustment mechanism for the calculation cycle that incorporates load changes. Within the default calculation cycle, the system monitors grid load shunting commands in real time, prioritizing commands with load changes ≥ 5% of the rated load to trigger coal calorific value calculation. If multiple load change windows that meet the requirements appear within the default calculation cycle, calculation is triggered only with the first valid window. After the calculation is completed, the timing for the next default calculation cycle is restarted. If no load change window that meets the requirements is captured by the end of the default calculation cycle, the system extends the waiting time. During this period, if a command with a load change ≥ 3% of the rated load appears, calculation can be triggered.

[0086] In some embodiments, the default calculation period for a method of calculating the real-time calorific value of coal fed into an ammonia-blended boiler is related to the unit type. If the unit is a main thermal power unit, the default calculation period is 2h to 4h; if the unit is a peak-shaving unit, the default calculation period is 1h to 2h.

[0087] Furthermore, by comparing the real-time calculated calorific value of the coal fed into the furnace with historical benchmark values, and determining whether to update the database based on a preset threshold for updating the calorific value of the coal fed into the furnace, the validity of the real-time calculation results can be verified. If the difference exceeds the preset threshold for updating the calorific value of the coal fed into the furnace, it indicates that the current calorific value of the coal fed into the furnace may have changed significantly. Updating the database ensures that the historical benchmark values ​​for subsequent calculations are timely and representative. If the difference does not exceed the preset threshold for updating the calorific value of the coal fed into the furnace, maintaining the benchmark value unchanged ensures the stability of the calculated data and avoids frequent adjustments due to minor fluctuations. On the other hand, this step forms a dynamic management mechanism for the calorific value data of the coal fed into the furnace. The real-time updating of the calorific value database of the coal fed into the furnace can accumulate calorific value data for different coal types and different load conditions for the power plant. This data can not only be used as a benchmark reference for subsequent calculations, but also provide long-term data support for the power plant's fuel procurement, inventory management, and combustion optimization strategy formulation, thereby improving the overall refined management level of the power plant's operation.

[0088] See Figure 3 This application provides a real-time calorific value calculation system for coal fed into an ammonia-blended boiler, comprising the following modules:

[0089] The coal feed rate regulation lag window determination module 100 is used to receive the power grid load dispatching command, record the stable initial value of the coal feed rate control signal, and collect the steam valve opening, main steam pressure and main steam flow. By judging the time when the steam valve opening, main steam pressure and main steam flow meet the preset stable conditions, and the time when the coal feed rate control signal first deviates from the stable initial value, the coal feed rate regulation lag time window is determined.

[0090] The ammonia blending operation data acquisition module 200 is connected to the coal feed rate adjustment lag window determination module 100. It is used to trigger the ammonia burner to perform ammonia blending combustion within the coal feed rate adjustment lag time window, and synchronously collect real-time operating data of boiler monitoring power generation, total coal consumption per unit time, and total ammonia consumption per unit time through the distributed control system.

[0091] The thermal inertia compensation power calculation module 300 is connected to the ammonia-blended operating condition data acquisition module 200. It is used to call the boiler monitoring power generation data output by the ammonia-blended operating condition data acquisition module, substitute it into the thermal inertia compensation model, and calculate the compensated real-time power generation of the boiler within the power generation change rate monitoring window.

[0092] The real-time calorific value calculation module 400 for coal fed into the furnace is connected to the ammonia blending condition data acquisition module 200 and the thermal inertia compensation power calculation module 300. It is used to call the total coal consumption per unit time and the total ammonia consumption per unit time data output by the ammonia blending condition data acquisition module and the real-time power generation data of the boiler output by the thermal inertia compensation power calculation module, and substitute them into the calorific value calculation model to calculate the real-time calorific value of the coal fed into the furnace.

[0093] The calorific value data verification and update module 500 is connected to the real-time calorific value calculation module 400 for coal fed into the boiler. It is used to call the real-time calorific value of coal fed into the boiler output by the real-time calorific value calculation module for coal fed into the boiler and compare it with the historical benchmark value of calorific value of coal fed into the boiler. Based on the relationship between the difference and the preset threshold for updating the calorific value of coal fed into the boiler, it triggers the real-time calorific value database to be updated or maintains the historical benchmark value and outputs instructions to the boiler control system.

[0094] The modules of this invention are designed to be closely integrated with the existing ammonia-blended combustion system and distributed control system of the power plant, eliminating the need for additional independent data acquisition or combustion experiment devices. Specifically, the ammonia-blended operating condition data acquisition module directly calls the distributed control system to obtain core parameters such as boiler power generation and coal-ammonia consumption in real time. The coal feed rate regulation lag window determination module relies on the distributed control system's monitoring function of steam valves and coal feed rate control signals to accurately define the time window, without requiring additional complex hardware. This adaptability design significantly reduces the cost and technical difficulty of system deployment, enabling rapid integration into the existing power plant operating system and avoiding disruption to normal power plant production due to modifications. The system employs multiple design features to eliminate key interference factors during the calculation process: Firstly, the coal feed rate adjustment lag window determination module accurately captures the time interval between the completion of steam valve adjustment and the first change in coal feed rate, ensuring that ammonia-blended combustion and data acquisition both occur within a stable coal feed rate window, thus avoiding the impact of coal feed rate fluctuations on power monitoring and calorific value calculation. Secondly, the ammonia-blended operating condition data acquisition module filters the collected real-time operating data to remove high-frequency noise interference. Simultaneously, the thermal inertia compensation power calculation module uses a professional model to correct the deviation of boiler thermal inertia in power generation monitoring, making the compensated power data more closely match the actual energy output. These multiple anti-interference designs ensure more accurate calculation data, providing reliable support for subsequent calorific value calculations. The system's various modules work collaboratively to form an efficient real-time measurement link: the coal feed rate adjustment lag window determination module can quickly respond to power grid load adjustment commands, monitor changes in steam valves and coal feed rate signals in real time, and define the effective time window within seconds; the ammonia blending condition data acquisition module synchronously collects operating data at a frequency of no less than 1Hz to ensure data timeliness; the thermal inertia compensation power calculation module and the real-time calorific value calculation module of the coal fed into the boiler are dynamically calculated based on real-time data, and can output the latest real-time calorific value of the coal fed into the boiler in a timely manner under complex operating conditions such as load changes and ammonia blending ratio adjustments. This real-time response capability overcomes the time lag problem of traditional offline sampling analysis, can quickly reflect changes in coal quality, and provide immediate data support for boiler combustion adjustment.

[0095] This invention establishes a closed-loop management system for calorific value data through a calorific value data verification and update module. It compares the real-time calculated calorific value of the coal fed into the boiler with historical benchmark values, and determines whether to update the database based on a preset threshold set according to the coal type characteristics. This avoids frequent adjustments caused by minor fluctuations while promptly capturing significant changes in coal quality, ensuring the timeliness and representativeness of historical benchmark values. Simultaneously, the real-time updated calorific value database accumulates calorific value data for different coal types and load conditions. This not only provides accurate benchmarks for subsequent calculations but also supports power plant fuel procurement, inventory management, and the development of long-term combustion optimization strategies, facilitating refined power plant operations. The system's final output of the real-time calorific value of the coal fed into the boiler can be directly fed back to the boiler control system. When the calculation results show an increase or decrease in the coal's calorific value, the boiler control system can precisely adjust combustion parameters such as coal feed rate and ammonia blending ratio based on this data, ensuring a precise match between fuel quantity and load demand—avoiding coal waste due to excessively high calorific value and preventing insufficient load due to excessively low calorific value. This combustion optimization based on real-time calorific value data can effectively improve boiler combustion efficiency and reduce ineffective energy consumption. At the same time, combined with the low-carbon properties of ammonia-blended combustion, it can further improve the overall energy utilization efficiency of the power plant while reducing carbon emissions.

[0096] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A method for real-time calculation of the calorific value of coal fed into an ammonia-blended boiler, characterized in that, Includes the following steps: The coal feed rate regulation lag time window is determined by monitoring the completion time of steam valve regulation and the start time of coal feed rate control signal response before and after the power grid load dispatch command is triggered. Ammonia blending operation data acquisition: During the coal feed rate adjustment lag time window, ammonia blending combustion is carried out, and real-time operating data including boiler monitoring power generation, total coal consumption per unit time, and total ammonia consumption per unit time are collected simultaneously. Thermal inertia compensation calculation: Based on the boiler's monitored power generation, dynamic compensation is performed according to the thermal inertia compensation model to calculate the boiler's real-time power generation after eliminating the influence of thermal inertia. The real-time calorific value of the coal fed into the furnace is calculated based on the real-time power generation of the boiler, the total coal consumption per unit time, and the total ammonia consumption per unit time, using a calorific value calculation model. The calorific value data is verified and updated by comparing the real-time calorific value of the coal fed into the furnace with the historical benchmark value. Based on the comparison result and the preset threshold for updating the calorific value of the coal fed into the furnace, it is determined whether to update the historical benchmark value.

2. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 1, characterized in that, The specific steps for determining the lag time window of coal feed rate adjustment include: Before receiving the power grid load dispatching command, record the stable initial value F0 of the coal feed control signal before the load dispatching command; After receiving the power grid load dispatching command, monitor the steam valve opening, main steam pressure and main steam flow. When all three meet the preset stability conditions, record time t1. The moment t2 when the coal feed rate control signal first deviates from F0 is monitored; The coal feed rate adjustment lag time window is [t1, t2]; wherein, the preset stability conditions include no change in the steam valve opening for more than 3 consecutive seconds, main steam pressure fluctuation amplitude ≤0.2MPa and main steam flow fluctuation amplitude ≤2%.

3. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 2, characterized in that, It also includes validating the coal feed rate adjustment lag time window [t1, t2]: if the time difference between t2 and t1 is no more than 30 seconds, the window is deemed invalid and the current calorific value calculation is cancelled.

4. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 1, characterized in that, In the ammonia blending operation data acquisition step, the real-time operating data needs to be filtered to remove high-frequency noise.

5. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 1, characterized in that, In the thermal inertia compensation calculation step, the thermal inertia compensation model is as follows: in, The real-time power generation of the boiler, calculated using the thermal inertia compensation model, is expressed in MW. The boiler monitoring power output displayed on the distributed control system panel is in MW; T is the boiler thermal inertia time constant in seconds, which is obtained through boiler thermodynamic characteristic experiments. The rate of change in boiler power generation is measured in MW / s.

6. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 5, characterized in that, The boiler monitors the rate of change in power generation. Calculated in the following way: in, The time superimposed after the start of ammonia-blended combustion is called the pure time delay. The determined pure time delay, for Real-time boiler power generation monitoring This refers to a monitoring point within a dynamic upward phase, satisfying T / 10 ≤ ≤T / 20, for The boiler's power generation is monitored at any given time, and the pure delay time τ and the dynamic rise stage are calibrated through boiler thermodynamic characteristic tests.

7. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 5, characterized in that, The calculation time window [t] for the boiler power generation change rate monitoring τ The value of t] must fall entirely within the coal feed rate adjustment lag time window [t1, t2].

8. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 1, characterized in that, In the step of calculating the real-time calorific value of the coal fed into the furnace, the calorific value calculation model is as follows: ,in, This indicates the real-time calorific value of the coal fed into the furnace, expressed in MJ / kg. To determine boiler power generation efficiency, it is necessary to calibrate using boiler design parameters or historical operating data. This indicates the total ammonia consumption of the boiler per unit time, expressed in kg / s. The lower heating value of ammonia is expressed as 18.6 MJ / kg. This indicates the total coal consumption of the boiler per unit time, expressed in kg / s.

9. The method for calculating the real-time calorific value of coal fed into an ammonia-blended boiler according to claim 1, characterized in that, In the calorific value data verification and update step, the historical benchmark value The initial value is the calorific value of the coal fed into the furnace, based on the coal quality test report. Subsequent values ​​are the most recently calculated and stored real-time calorific value of the coal fed into the furnace. In the comparison step, the real-time calorific value of the coal fed into the furnace is determined. Compared with the historical benchmark value Whether the absolute value of the difference exceeds the preset threshold for updating the calorific value of the coal fed into the furnace, wherein the preset threshold for updating the calorific value of the coal fed into the furnace is set according to the characteristics of the coal type.

10. A system for real-time calorific value calculation of coal feed into an ammonia-blended boiler for implementing the method described in any one of claims 1-9, characterized in that, include: The coal feed rate regulation lag window determination module is used to receive the grid load dispatching command, record the stable initial value of the coal feed rate control signal, and collect the steam valve opening, main steam pressure and main steam flow. By judging the time when the steam valve opening, main steam pressure and main steam flow meet the preset stable conditions, and the time when the coal feed rate control signal first deviates from the stable initial value, the coal feed rate regulation lag time window is determined. The ammonia blending operation data acquisition module is connected to the coal feed rate adjustment lag window determination module. It is used to trigger the ammonia burner to perform ammonia blending combustion within the coal feed rate adjustment lag time window, and synchronously acquire real-time operating data of boiler monitoring power generation, total coal consumption per unit time, and total ammonia consumption per unit time through the distributed control system. The thermal inertia compensation power calculation module is connected to the ammonia-blended operating condition data acquisition module. It is used to call the boiler monitoring power generation data output by the ammonia-blended operating condition data acquisition module, substitute it into the thermal inertia compensation model, and calculate the compensated real-time power generation of the boiler. The real-time calorific value calculation module for coal fed into the furnace is connected to the ammonia-blended operating condition data acquisition module and the thermal inertia compensation power calculation module. It is used to call the total coal consumption per unit time and the total ammonia consumption per unit time data output by the ammonia-blended operating condition data acquisition module and the real-time power generation data of the boiler output by the thermal inertia compensation power calculation module, and substitute them into the calorific value calculation model to calculate the real-time calorific value of the coal fed into the furnace. The calorific value data verification and update module is connected to the real-time calorific value calculation module for the coal fed into the furnace. It is used to call the real-time calorific value of the coal fed into the furnace output by the real-time calorific value calculation module for the coal fed into the furnace, and compare it with the historical benchmark value of the calorific value of the coal fed into the furnace. Based on the relationship between the difference and the preset threshold for updating the calorific value of the coal fed into the furnace, it triggers the real-time calorific value database update or maintains the historical benchmark value, and outputs instructions to the boiler control system.

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