Power plant denitration ammonia injection amount optimization control system

Abstract

A denitration ammonia injection amount optimization control system for a power plant relates to the technical field of automatic control, and comprises the following steps: step S01, an optimization controller calculates an ammonia injection amount optimization set value according to historical coal amount, air amount, oxygen amount, ammonia injection amount, a nitrogen oxide process value and a nitrogen oxide set value in a set period; s02, the real-time controller carries out calculation every T seconds, the real-time value of the set value of the ammonia spraying amount is calculated, the real-time value and the optimized value of the set value of the ammonia spraying amount jointly form a final set value of the ammonia spraying amount through a decision maker, and optimization of the ammonia spraying amount is achieved. On one hand, the ammonia spraying amount and NOx can be controlled and stabilized in real time, and on the other hand, the denitration stability of the power plant is ensured by searching the optimal ammonia spraying amount through optimization.

Description

Technical Field

[0001] This invention relates to the field of automatic control technology, and in particular to a power plant denitrification ammonia injection quantity optimization control system. Background Technology

[0002] In thermal power plants, electricity is mainly generated by burning coal. However, coal combustion produces harmful nitrogen oxides (NOx). NOx is generally divided into thermal NOx and fuel NOx. Thermal NOx is generated by the reaction of nitrogen and oxygen in the air at high temperatures. Fuel NOx is generated by the oxidation of nitrogen compounds in fuel during combustion. Power plant denitrification refers to the process of removing NOx from flue gas before it is emitted from a thermal power plant, using ammonia injection technology. Because there is a significant lag between NOx detection in the emitted flue gas and boiler combustion, and because boiler coal, air volume, and oxygen levels have a significant impact on NOx production, it is difficult to find the ideal ammonia injection rate using traditional feedback control. Excessive ammonia injection can cause secondary pollution, while insufficient injection will result in NOx emissions failing to meet standards. Therefore, it is necessary to design an optimized ammonia injection rate control method for power plant denitrification. This method can stabilize the ammonia injection rate and NOx levels through real-time control, and optimize the injection rate to ensure the stability of power plant denitrification. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a power plant denitrification ammonia injection quantity optimization control system, the purpose of which is to ensure the stability of the power plant denitrification process through optimized control of the power plant denitrification ammonia injection quantity.

[0004] A power plant denitrification ammonia injection rate optimization control system includes the following main steps: Step S01: The controller optimizes the calculation according to the set cycle, and calculates the optimized setting value of ammonia injection based on the historical coal quantity, air quantity, oxygen quantity, ammonia injection quantity, nitrogen oxide process value and nitrogen oxide set value.

[0005] Step S02: The real-time controller calculates the real-time value of the ammonia injection rate setpoint every T seconds. Through the decision-maker, the setpoint and the optimized value of the ammonia injection rate setpoint are combined to form the final setpoint of the ammonia injection rate, thereby optimizing the ammonia injection rate. The power plant denitrification ammonia injection rate optimization control system injects ammonia according to the final setpoint of the ammonia injection rate.

[0006] Further, step S01 specifically includes the following steps: Step S101: Every 300 times the real-time controller cycle, obtain the sampled values ​​of the N coal quantity, air quantity, oxygen quantity, ammonia injection quantity, nitrogen oxide process value and nitrogen oxide setpoint of the boiler at the current moment, and construct them into a time list data.

[0007] Obtain the N process values ​​preceding the current boiler time, and construct the original time list of boiler process values: (Formula 1); in, This represents a list of original times for boiler process values. This represents the Nth sampled value of the boiler process value, where N represents the number of original sampled values. When the name is "coal", it indicates the amount of coal; when the name is "air", it indicates the air volume; when the name is "O2", it indicates the amount of oxygen; when the name is "NH3", it indicates the amount of ammonia injected; and when the name is "NOX", it indicates the amount of nitrogen oxides. Symbols: rawPVlist stands for raw-process-value-list (original list of process values), and PV stands for process-value (process value).

[0008] Obtain the N previous NOx setpoints of the boiler at the current time to construct the original time list of boiler NOx setpoints: (Formula 2); in, This indicates the original time list of boiler nitrogen oxide setpoints. This represents the Nth sampled value of the boiler's nitrogen oxide setpoint, where N represents the number of original sampled values. Symbols: rawSPlist stands for raw-setpoint translation of the original setpoint list, SP stands for setpoint translation of the setpoint, and so on.

[0009] Based on the constraints, appropriate historical values ​​are selected from the original time list, and the time series is constructed by appending to a new empty list. The specific process is as follows: (1) Setting list , The list length L=0.

[0010] (2) If ,but L = L_1 + 1, otherwise = , = , L=L_1, i=1……N.

[0011] in, This represents a list of boiler process value times. This represents the time list for boiler process value i-1. This represents a list of original times for boiler process values. This indicates a list of boiler nitrogen oxide setpoint times. This represents the time list at time i-1 when the boiler's nitrogen oxide setpoint is reached. This indicates the original time list of boiler nitrogen oxide setpoints. This represents the constraint value under the boiler process value. This represents the constraint value on the boiler process value, where L represents the list length and L_1 represents the list length at time i-1. This indicates adding a new value to the list. When the name is "coal," it represents the amount of coal; when the name is "air," it represents the amount of air; when the name is "O2," it represents the amount of oxygen; when the name is "NH3," it represents the amount of ammonia injected; and when the name is "NOX," it represents the amount of nitrogen oxides. Symbols: PVlist stands for process-value-list, SPlist stands for setpoint-list, and so on.

[0012] Step S102: When the process value time list L is greater than 0.632*N, calculate the process value mean, increment value, settling time and stability.

[0013] (1) Average of process value and setpoint time list: Calculate the average of the time list of process values: (Formula 3); in, This represents the average value of the boiler process over time. This represents a list of boiler process values ​​over time. When the name is "coal", it indicates the amount of coal; when the name is "air", it indicates the amount of air; when the name is "O2", it indicates the amount of oxygen; when the name is "NH3", it indicates the amount of ammonia injected; when the name is "NOX", it indicates the amount of nitrogen oxides; and L indicates the length of the list.

[0014] Calculate the average of the nitrogen oxide setpoint time list: (Formula 4); in, This represents the average value of the boiler's nitrogen oxide setpoint over a period of time. This represents the time list of boiler nitrogen oxide setpoints, where L represents the list length.

[0015] (2) Process value time list increment value: Calculate the incremental values ​​in the time list of process values: (Formula 5); in, This represents the cumulative incremental value of boiler process values. When the name is "coal," it indicates coal quantity; when the name is "air," it indicates air quantity; when the name is "O2," it indicates oxygen quantity; when the name is "NH3," it indicates ammonia injection quantity; and when the name is "NOX," it indicates nitrogen oxide quantity. "L" indicates the list length. Symbols: The process-value-difference-sum is the cumulative incremental value of the process value, and the same applies below.

[0016] (3) Process value stable space-time list: Construction process value stable space-time list: (Formula 6); in, This represents a list of stable space-time values ​​for boiler processes. This represents the time series mean of the boiler coal quantity process value. This represents a time-varying list of boiler coal quantity process values. This represents the time series mean of the boiler air volume process value. This represents a time-varying list of boiler air volume process values. This represents the time series mean of the boiler oxygen content. This represents a time-series list of boiler oxygen quantity process values. `max` indicates calculating the maximum value, and `L` represents the list length. Symbols: The process-value-stability-list is a list of process-value stable space-time values, and the same applies below.

[0017] (4) Cumulative boiler stabilization time: Calculate the cumulative value of the steady-state time: (Formula 7); in, This indicates the cumulative time for the boiler process value to stabilize. This represents the time series mean of the boiler coal quantity process value. This represents a time-varying list of boiler coal quantity process values. This represents the time series mean of the boiler air volume process value. This represents a time-varying list of boiler air volume process values. This represents the time series mean of the boiler oxygen content. This represents a time-based list of boiler oxygen quantity process values, where L indicates the list length. Symbol: The steady-state cumulative time for translating process-value-steady-time-sum is the same below.

[0018] (5) Boiler stability: Calculate boiler stability: (Formula 8); in, Indicates the stability of boiler process values. This indicates the cumulative time for boiler process values ​​to stabilize. Symbol: The term "process-value-stability" refers to the stability of process values, and the same applies below.

[0019] Step S103: Calculate the baseline value for optimized ammonia injection setpoint based on the stability of the boiler process values.

[0020] Calculation method for the baseline value of optimized ammonia injection settings: When the stability of boiler process values hour: (Formula 9); When the stability of boiler process values hour: (Formula 10); in, This indicates the optimized baseline value for boiler ammonia injection settings. This list represents the time values ​​for the boiler ammonia injection process. This represents a list of stable space-time values ​​for boiler processes. This indicates the stability of boiler process values, where L represents the list length. Symbols: The reference-setpoint is set as the baseline value, and the same applies below.

[0021] Step S104: When the baseline value of the boiler ammonia injection setting optimization value is less than the constraint value under the nitrogen oxide process value, calculate the optimized value of the ammonia injection quantity setting value based on the deviation between the nitrogen oxide setting value and the process value.

[0022] if The optimized ammonia injection rate setting is as follows: (Formula 11); Otherwise, the optimized value for the ammonia injection rate setting is:

[0023] (Formula 12); in, This indicates the optimized value of the ammonia injection rate setpoint. This indicates the optimized baseline value for boiler ammonia injection settings. This represents the average value of the boiler's nitrogen oxide setpoint over a period of time. This represents the average value of the boiler nitrogen oxide process values ​​over time.

[0024] Step S105: When the absolute value of the deviation between the average value of the nitrogen oxide setpoint time list and the average value of the nitrogen oxide process value time list is less than 0.1 * the average value of the nitrogen oxide setpoint time list, calculate the optimized value of the ammonia injection setpoint based on the incremental value of the boiler process value time list.

[0025] The optimized ammonia injection rate setting is as follows: (Formula 13); in, This indicates the optimized value of the ammonia injection rate setpoint. This indicates the optimized baseline value for boiler ammonia injection settings. This represents the constraint value under the process value of boiler ammonia injection. This represents the cumulative value of the process change in boiler coal quantity. This represents the cumulative value of the process change in boiler coal oxygen content. This represents the cumulative change in boiler blast volume over a given period. Symbol: The optimal-setpoint is the setpoint value, and the same applies below.

[0026] Step S106: When the absolute value of the deviation between the average value of the nitrogen oxide setpoint time list and the average value of the nitrogen oxide process value time list is greater than or equal to 0.1 * the average value of the nitrogen oxide setpoint time list, calculate the optimized value of the ammonia injection rate setpoint.

[0027] The calculation method for the optimized value of the ammonia injection rate setpoint is the same as that for "Formula 11" and "Formula 12".

[0028] Furthermore, step S02 specifically includes the following steps: Step S201: The control cycle of the nitrogen oxide real-time controller is T seconds. The real-time value of the ammonia injection rate setpoint is calculated based on the deviation between the nitrogen oxide process value and the setpoint.

[0029] The real-time nitrogen oxide controller calculates the real-time value of the ammonia injection rate setpoint based on the deviation between the nitrogen oxide process value and the setpoint. The calculation formula is as follows:

[0030] (Formula 14); in, This indicates the real-time value of the ammonia injection rate setpoint. This indicates the real-time value of the ammonia injection rate set for one cycle. This indicates that the control weight of the real-time nitrogen oxide controller is 1. This represents the real-time value of the nitrogen oxide process. This represents the real-time value of the nitrogen oxide process over one cycle. This indicates that the control weight of the real-time nitrogen oxide controller is 2. This indicates the real-time setpoint value for nitrogen oxides. Symbol: For real-time-setpoint Translate real-time settings. Translate real-time process value. The term "control-weight" is translated as "control weight" or "control weight" in this context.

[0031] Step S202: Based on the process value and setpoint real-time value of nitrogen oxides, the setpoint real-time value and optimized value of ammonia injection quantity, the decision controller performs weighting and outputs the final ammonia injection setpoint.

[0032] The calculation method for the decision controller is as follows: (1) If ,and The final set value for ammonia injection rate is: (Formula 15); in, This represents the real-time value of the nitrogen oxide process. This indicates the real-time value of the nitrogen oxide setpoint. This indicates the real-time value of the ammonia injection rate setpoint. This indicates the optimized value of the ammonia injection rate setpoint. This indicates a decision-maker weight of 1. Symbol: For real-time and optimal setpoint translation, set real-time and optimal values. The term "decision-weight" is used to translate "decision weight" (the same applies below).

[0033] (2) If ,and The final set value for ammonia injection rate is: (Formula 16); in, This represents the real-time value of the nitrogen oxide process. This indicates the real-time value of the nitrogen oxide setpoint. This indicates the final set value for the ammonia injection rate. This indicates the real-time value of the ammonia injection rate setpoint. This indicates the optimized value of the ammonia injection rate setpoint. This indicates that the decision-maker weight is 2.

[0034] (3) If neither "(1)" nor "(2)" is satisfied, then the final set value of the ammonia injection rate is: (Formula 13); in, This indicates the final set value for the ammonia injection rate. This indicates the real-time value of the ammonia injection rate setting.

[0035] Step S203: The control cycle of the ammonia injection quantity real-time controller is T seconds. The opening degree of the ammonia injection valve is calculated based on the deviation between the process value and the set value of the ammonia injection quantity.

[0036] The ammonia injection rate real-time controller calculates the real-time opening degree of the ammonia injection valve based on the deviation between the real-time process value and the final set value of the ammonia injection rate. The calculation formula is as follows: (Formula 17); in, This indicates the real-time output value of the ammonia injection valve. This indicates the real-time output value of the ammonia injection valve over one cycle. This indicates that the real-time ammonia injection controller has a control weight of 1. This indicates the real-time value of the ammonia injection rate. This represents the real-time value of the ammonia injection rate over one cycle. This indicates that the real-time ammonia injection controller has a control weight of 2. This indicates the final set value for the ammonia injection rate.

[0037] Compared with existing technologies, this technical solution has the following characteristics: 1. The power plant denitrification controller is divided into an optimization controller and a real-time controller. The optimization controller calculates the optimized value of the denitrification ammonia injection setpoint every 300 times the cycle of the real-time controller. The real-time controller is used to stabilize nitrogen oxides and ammonia injection in real time, which can ensure that the power plant denitrification control can both optimize the ammonia injection and ensure the real-time performance of denitrification control. 2. The power plant denitrification optimization controller first uses the processed historical data to calculate the optimized benchmark value of the ammonia injection rate setpoint, which can ensure the reliability of the calculation of the optimized value of the ammonia injection rate setpoint. 3. The optimized value of the ammonia injection rate setting is obtained by weighting the benchmark value of the ammonia injection rate setting based on the air volume, oxygen volume, coal volume, and nitrogen oxides, thus ensuring the accuracy of the optimized value. 4. The decision-maker selects whether to perform ammonia injection rate optimization tracking based on the actual situation of the nitrogen oxide process value and the setpoint real-time value, the ammonia injection rate setpoint real-time value and the optimized value, which can ensure the stability of denitrification control. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of ammonia injection for power plant denitrification according to the present invention; Figure 2 This is a schematic diagram of the power plant denitrification ammonia injection quantity optimization control system of the present invention; Figure 3 This is a schematic diagram of the optimized control process for ammonia injection rate in power plant denitrification according to the present invention; Figure 4 This is a schematic diagram of the process for optimizing ammonia injection rate in power plant denitrification according to the present invention. Figure 5 This is a schematic diagram of the real-time control method for ammonia injection in power plant denitrification according to the present invention. Detailed Implementation

[0039] The specific implementation process of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1-5 As shown, this invention provides a power plant denitrification ammonia injection quantity optimization control system, including the following steps: Step S01: The optimization controller calculates the optimized ammonia injection quantity setting value every 300 times the real-time controller cycle, based on historical coal quantity, air quantity, oxygen quantity, ammonia injection quantity, nitrogen oxide process value, and nitrogen oxide set value. Step S02: The real-time controller calculates the real-time value of the ammonia injection quantity setting value every T seconds, and through the decision unit, it combines the optimized ammonia injection quantity setting value with the final ammonia injection quantity setting value to achieve optimization of the ammonia injection quantity.

[0041] This invention relates to a power plant denitrification controller, which is divided into an optimization controller and a real-time controller. The optimization controller calculates the optimized value of the ammonia injection setpoint for denitrification every 300 times the cycle of the real-time controller. The real-time controller is used to stabilize nitrogen oxides and ammonia injection in real time, ensuring that the power plant denitrification control can optimize the ammonia injection rate while maintaining real-time performance. The power plant denitrification optimization controller first calculates the optimized baseline value of the ammonia injection setpoint using processed historical data, ensuring the reliability of the calculation. The optimized value of the ammonia injection setpoint is then calculated by weighting the baseline value based on air volume, oxygen volume, coal volume, and nitrogen oxides, finally obtaining the optimized value and ensuring its accuracy. The decision-maker selects whether to perform ammonia injection setpoint optimization tracking based on the actual situation of nitrogen oxide process values, real-time setpoint values, and optimized values ​​of the ammonia injection setpoint, ensuring the stability of denitrification control. This invention enables optimized control of ammonia injection in power plant denitrification, resulting in more stable nitrogen oxide control.

[0042] The system of this invention communicates with the field control system via OPC (OLE for Process Control) to acquire and write back data, and the acquired data can be stored in a database.

[0043] Example 1: Assume a power plant is equipped with a 260t / h circulating fluidized bed boiler. Historical data and data write-back are collected from the control system via OPC communication.

[0044] According to the method proposed in this invention, the following two main processes are calculated respectively: Step S01: The optimization controller performs calculations every 300 times the real-time controller cycle, and calculates the optimized setting value of ammonia injection based on historical coal quantity, air quantity, oxygen quantity, ammonia injection quantity, nitrogen oxide process value and nitrogen oxide set value.

[0045] Step S02: The real-time controller performs calculations every T=3 seconds to calculate the real-time value of the ammonia injection rate setpoint. Through the decision-maker, the real-time value of the ammonia injection rate setpoint is combined with the optimized value of the ammonia injection rate setpoint to form the final setpoint of the ammonia injection rate, thereby optimizing the ammonia injection rate.

[0046] Specifically, step S01 includes the following functions: Step S101: Every 300*3 seconds=900 seconds, obtain the sampled values ​​of coal quantity, air quantity, oxygen quantity, ammonia injection quantity, nitrogen oxide process value and nitrogen oxide set value before the current time of the boiler, and construct them into a time list data.

[0047] Obtain the N=5400 process values ​​preceding the current boiler time, and construct the original time list of boiler process values: Coal quantity (unit: t / h): ; Air volume (unit: Nm3 / h): ; Oxygen content (unit: %):

[0048] ; Ammonia injection rate (unit: kg / h): ; Nitrogen oxides (unit: mg / m³) 3 ): ; Obtain the N=5400 previous NOx setpoints of the boiler at the current time, and construct the original time list of boiler NOx setpoints: .

[0049] Based on the constraints, appropriate historical values ​​are selected from the original time list, and the time series is constructed by appending to a new empty list. The specific process is as follows: Given the constraint values ​​on the boiler process values: , , , , Boiler process values ​​under constraint: , , , , .

[0050] Calculation of coal quantity, air quantity, oxygen quantity, ammonia injection quantity, nitrogen oxide process value, and nitrogen oxide setpoint time list: (1) Setting list , , , , , The list length L=0.

[0051] (2) When i=1, If the condition is met, then , , , , L = 0 + 1 = 1. And so on, as i = 2...5400, a total of L = 4780 data points satisfy the requirements, ultimately yielding the time list: Coal quantity process value time list (unit: t / h): ; Air volume process value (unit: Nm) 3 / h): ; Oxygen content process value (unit: %): ; Ammonia injection rate (unit: kg / h): ; Nitrogen oxide process values ​​(unit: mg / m³) 3 ): ; List of nitrogen oxide setpoints by time (unit: mg / m³) 3 ): .

[0052] Step S102: When the process value time list L=4780 is greater than 0.632*N=0.632*5400=3412.8, calculate the process value mean, increment value, steady time and stability.

[0053] (1) Average of process value and setpoint time list: Average value of coal quantity process value over time: ; Average value of air volume process value over time: ; Oxygen process value time list average: ; Average values ​​of ammonia injection rate over time: ; Average of nitrogen oxide process values ​​over time: ; Average of nitrogen oxide setpoints over time: .

[0054] (2) Process value time list increment value: Coal quantity process value time list increment value: ; Air volume process value time list increment value: ; Oxygen process value time list increment value: .

[0055] (3) Process value stable space-time list: Construction process value stable space-time list: .

[0056] (4) Cumulative boiler stabilization time: Calculate the cumulative value of the steady-state time: .

[0057] (5) Boiler stability: Calculate boiler stability: .

[0058] Step S103: Calculate the baseline value for optimized ammonia injection setpoint based on the stability of the boiler process values.

[0059] Due to the stability of boiler process values Calculation of the baseline value for optimized ammonia injection settings: .

[0060] Due to the optimized baseline value of ammonia injection settings Furthermore, the absolute value of the deviation between the average value of the nitrogen oxide setpoint time list and the average value of the nitrogen oxide process value time list is greater than or equal to 0.1 * the average value of the nitrogen oxide setpoint time list, i.e. Therefore, proceed with "Step 106".

[0061] Step S106: When the absolute value of the deviation between the average value of the nitrogen oxide setpoint time list and the average value of the nitrogen oxide process value time list is greater than or equal to 0.1 * the average value of the nitrogen oxide setpoint time list, calculate the optimized value of the ammonia injection rate setpoint.

[0062] because The optimized ammonia injection rate setpoint is: .

[0063] Furthermore, step S02 specifically includes the following steps: Step S201: The control cycle of the nitrogen oxide real-time controller is T=3 seconds. The real-time value of the ammonia injection quantity setpoint is calculated based on the deviation between the nitrogen oxide process value and the setpoint.

[0064] Known ammonia injection rate, set for one cycle, in real-time. The control weight of the real-time nitrogen oxide controller is 1. The real-time controller for nitrogen oxides has a control weight of 2. Real-time value of nitrogen oxide process real-time value of nitrogen oxide setpoint Real-time value of nitrogen oxides in the first cycle process .

[0065] The real-time nitrogen oxide controller calculates the real-time value of the ammonia injection rate setpoint based on the deviation between the nitrogen oxide process value and the setpoint. The calculation formula is as follows: .

[0066] Step S202: Based on the process value and setpoint real-time value of nitrogen oxides, the setpoint real-time value and optimized value of ammonia injection quantity, the decision controller performs weighting and outputs the final ammonia injection setpoint.

[0067] Given that the decision-maker weight is 1 .

[0068] because ,and The final set value for ammonia injection rate is: .

[0069] Step S203: The control cycle of the ammonia injection quantity real-time controller is T=3 seconds. The opening degree of the ammonia injection valve is calculated based on the deviation between the process value and the set value of the ammonia injection quantity.

[0070] Given the real-time output value of the ammonia injection valve for one cycle. The real-time ammonia injection controller has a control weight of 1. Real-time value of ammonia injection rate over one cycle. Real-time value of ammonia injection process The real-time ammonia injection controller has a control weight of 2. .

[0071] The ammonia injection rate real-time controller calculates the real-time opening degree of the ammonia injection valve based on the deviation between the real-time process value and the final set value of the ammonia injection rate. The calculation formula is as follows: .

Claims

1. A power plant denitration ammonia injection amount optimization control system, characterized by, The optimization controller, the real-time controller, and the decision maker perform the following steps: Step S01: The optimization controller calculates the optimized set value of the ammonia injection amount according to the historical coal amount, air amount, oxygen amount, ammonia injection amount, nitrogen oxide process value, and nitrogen oxide set value at a set period; Step S02: The real-time controller calculates the real-time value of the ammonia injection amount set value every interval T seconds, and the decision maker combines the optimized value of the ammonia injection amount set value to form the final set value of the ammonia injection amount, and the power plant denitration ammonia injection amount optimization control system sprays ammonia according to the final set value of the ammonia injection amount.

2. The ammonia injection amount optimization control system for denitration of a power plant according to claim 1, characterized by: Step S01 includes the following steps: Step S101: The optimization controller obtains the sampling values of the boiler current time N coal amount, air amount, oxygen amount, ammonia injection amount, nitrogen oxide process value, and nitrogen oxide set value at a set period, and constructs a time list data; Step S102: When the process value time list L is greater than 0.632*N, the mean value, incremental value, stability time, and stability are calculated; Step S103: According to the stability of the boiler process value, the optimized value reference value of the ammonia injection set value is calculated; Step S104: When the optimized value reference value of the boiler ammonia injection set value is less than the constraint value of the nitrogen oxide process value, the optimized value of the ammonia injection amount set value is calculated according to the deviation between the nitrogen oxide set value and the process value; Step S105: When the absolute value of the deviation between the mean value of the nitrogen oxide set value time list and the mean value of the nitrogen oxide process value time list is less than 0.1 times the mean value of the nitrogen oxide set value time list, the optimized value of the ammonia injection amount set value is calculated according to the incremental value of the boiler process value time list; Step S106: When the absolute value of the deviation between the mean value of the nitrogen oxide set value time list and the mean value of the nitrogen oxide process value time list is greater than or equal to 0.1 times the mean value of the nitrogen oxide set value time list, the optimized value of the ammonia injection amount set value is calculated according to step S104.

3. The system according to claim 2, wherein: Step S101 includes the following steps: Obtain the N process values of the boiler at the current time to form the original time list of the boiler process values: (Formula 1) wherein, represents a list of original time of boiler process value, represents the Nth sampling value of boiler process value, N represents the number of original sampling value, when name is coal, it represents coal amount, when name is air, it represents air amount, when name is O2, it represents oxygen amount, when name is NH3, it represents ammonia injection amount, when name is NOX, it represents nitrogen oxide amount; Obtain the N nitrogen oxide set values of the boiler at the current time to form the original time list of the boiler nitrogen oxide set values: (Formula 2) wherein, represents a boiler nitrogen oxide set value original time list, represents a boiler nitrogen oxide set value Nth sampling value, N represents the number of original sampling values; Select appropriate historical values from the original time list according to the constraints, and construct a time sequence by appending new empty lists: (1) Set list , , list length L = 0; (2) If then , L = L_1 + 1, otherwise = , = , L = L_1, i = 1 … N; wherein, represents a boiler process value time list, represents a boiler process value i-1 time list, represents a boiler process value original time list, represents a boiler nitrogen oxide set value time list, represents a boiler nitrogen oxide set value i-1 time list, represents a boiler nitrogen oxide set value original time list, represents a boiler process value lower constraint value, represents a boiler process value upper constraint value, L_1 represents an i-1 time list length, represents adding a new value to the list; represents a new value of the amount of nitrogen oxides in the set value list.

4. The ammonia injection amount optimization control system for denitration of a power plant according to claim 2, characterized by: Step S102 includes the following steps: (1) Mean value of process value and set value time list Calculate the mean value of the process value time list: (Formula 3) wherein, represents the mean of the list of boiler process value times, represents the list of boiler process value times; Calculate the mean value of the nitrogen oxide set value time list: (Formula 4) wherein, represents the mean of the boiler nitrogen oxides setpoint time list, represents the boiler nitrogen oxides setpoint time list; (2) Calculate the incremental value of the process value time list: (Formula 5) wherein represents a boiler process value delta accumulated value; (3) Construct the process value stability space time list: (Formula 6) wherein, represents a list of boiler process value steady space time, represents a time series mean of boiler coal quantity process value, represents a list of boiler coal quantity process value time, represents a time series mean of boiler air quantity process value, represents a list of boiler air quantity process value time, represents a time series mean of boiler oxygen quantity process value, represents a list of boiler oxygen quantity process value time; (4) Calculate the stability time cumulative value: (Formula 7) wherein, represents a boiler process value stable accumulation time, represents a boiler coal quantity process value time series mean, represents a boiler coal quantity process value time list, represents a boiler air quantity process value time series mean, represents a boiler air quantity process value time list, represents a boiler oxygen quantity process value time series mean, represents a boiler oxygen quantity process value time list; (5) Calculate the stability of the boiler: (Formula 8) wherein, represents the stability of the boiler process value, represents the stability accumulation time of the boiler process value.

5. The ammonia injection amount optimization control system for a power plant denitration according to claim 2, characterized by: Step S103 includes the following steps: When the stability of the boiler process value is time: (Formula 9) When the stability of the boiler process value is time: (Formula 10) wherein, represents a boiler ammonia injection set optimization reference value, represents a boiler ammonia injection quantity process value time list, represents a boiler process value stable space time list, represents a stability of a boiler process value.

6. The ammonia injection amount optimization control system for de-NOx of a power plant according to claim 2, characterized by: Step S104 includes the following steps: If The ammonia injection amount set value optimization value is: (Formula 11) Otherwise, the optimized value of the ammonia injection amount set value is: (Formula 12) wherein, represents an ammonia injection amount set value optimization value, represents a boiler ammonia injection set optimization reference value, represents a boiler nitrogen oxides set value time list average value, represents a boiler nitrogen oxides process value time list average value.

7. The ammonia injection amount optimization control system for de-NOx of a power plant according to claim 2, characterized by: Step S105 includes the following steps: When the absolute value of the deviation between the mean value of the nitrogen oxide set value time list and the mean value of the nitrogen oxide process value time list is less than 0.1 times the mean value of the nitrogen oxide set value time list, the optimized value of the ammonia injection amount set value is calculated according to the incremental value of the boiler process value time list: (Formula 13) wherein, represents an ammonia injection amount set value optimization value, represents a boiler ammonia injection set optimization reference value, represents a boiler ammonia injection amount process value lower constraint value, represents a boiler coal amount process value change cumulative value, represents a boiler coal oxygen amount process value change cumulative value, represents a boiler coal wind amount process value change cumulative value.

8. The ammonia injection amount optimization control system for de-NOx of a power plant according to claim 2, characterized by: Step S106 comprises the following steps: when the absolute value of the deviation between the nitrogen oxide set value time list average and the nitrogen oxide process value time list average is greater than or equal to 0.1*the nitrogen oxide set value time list average, the ammonia injection amount set value optimization value is calculated according to step S104.

9. The system according to claim 1, wherein: The step S02 comprises the following steps: Step S201: the nitrogen oxide real-time controller controls a period of T seconds, and calculates an ammonia injection amount set value real-time value according to a deviation between a nitrogen oxide process value and a set value; Step S202: according to the nitrogen oxide process value and the set value real-time value, the ammonia injection amount set value real-time value and an optimization value, a final ammonia injection set value is output through a decision controller by weighting; Step S203: the ammonia injection amount real-time controller controls a period of T seconds, and calculates an ammonia injection valve opening degree according to a deviation between an ammonia injection amount process value and a set value.

10. The ammonia injection amount optimization control system for a power plant denitration according to claim 9, characterized by, The step S201 comprises the following steps: The nitrogen oxide real-time controller calculates an ammonia injection amount set value real-time value according to a deviation between a nitrogen oxide process value and a set value, and the calculation formula is as follows: (Formula 14) wherein, represents the ammonia injection amount set value real-time value, represents the ammonia injection amount upper 1 period set value real-time value, represents the nitrogen oxide real-time controller control weight 1, represents the nitrogen oxide process value real-time value, represents the nitrogen oxide upper 1 period process value real-time value, represents the nitrogen oxide real-time controller control weight 2, represents the nitrogen oxide set value real-time value; The step S202 comprises a decision controller calculation method as follows: (1) If and then the final set value of the ammonia injection amount: (Formula 15) wherein represents a nitrogen oxide process value real-time value, represents a nitrogen oxide setpoint real-time value, represents an amount of ammonia to be injected setpoint real-time value, represents an amount of ammonia to be injected setpoint optimized value, represents a decision maker weight 1; (2) If and then the final set value of the ammonia injection amount: (Formula 16) wherein represents a nitrogen oxide process value real-time value, represents a nitrogen oxide setpoint real-time value, represents an ammonia injection amount final setpoint, represents an ammonia injection amount setpoint real-time value, represents an ammonia injection amount setpoint optimized value, represents a decision maker weight 2; (3) if neither (1) nor (2) in step S202 is satisfied, the final ammonia injection amount set value is: (Formula 13) wherein represents the final set value of the ammonia injection amount, represents the real-time value of the ammonia injection amount set value; The step S203 comprises that the ammonia injection amount real-time controller calculates an ammonia injection valve opening degree real-time opening degree according to a deviation between an ammonia injection amount process value real-time value and a final ammonia injection amount set value, and the calculation formula is as follows: (Formula 17) wherein, represents the real-time value of the ammonia injection valve output value, represents the real-time value of the ammonia injection valve output value in the first period, represents the real-time control weight of the ammonia injection amount, represents the real-time value of the ammonia injection amount process value, represents the real-time value of the ammonia injection amount process value in the first period, represents the real-time control weight of the ammonia injection amount, represents the final set value of the ammonia injection amount.

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