JP5252958B2 - Boiler control device and boiler control method - Google Patents

Description

  The present invention relates to a boiler control device that is installed in a thermal power plant or the like and burns fuel such as coal to generate working steam of the plant, and a boiler control method.

In general, as a technology for removing nitrogen oxides (NOx) contained in exhaust gas discharged from a boiler that is installed in a thermal power plant or the like and burns fuel such as coal and generates working steam of this plant, A system is employed in which a denitration device is installed on the downstream side, ammonia (NH ₃ ) is injected into the exhaust gas duct, and nitrogen oxides are reduced using a catalyst in the presence of ammonia.

  The denitration reaction occurring in the denitration catalyst layer of this denitration apparatus is a selective catalytic reduction reaction, and the reaction is according to the following chemical formula.

4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O (1)
As shown in the formula (1), in the selective catalytic reduction reaction, nitrogen oxides and ammonia in the exhaust gas react at a molar ratio of 1: 1. When the amount of ammonia injected is relatively small compared to nitrogen oxide, nitrogen oxide cannot be reduced, and more nitrogen oxide is discharged from the chimney.

  Conversely, when the amount of ammonia injected is relatively large compared to nitrogen oxide, ammonia flows into the air heater installed on the downstream side of the denitration apparatus, which causes the air heater to become clogged.

  In order to avoid these problems, it is necessary to inject ammonia without excess or deficiency in accordance with the distribution of nitrogen oxide concentration.

  In Japanese Patent Laid-Open No. 9-75673, in order to inject ammonia without excess or deficiency, a plurality of gas mixers are provided between the ammonia injection nozzle and the denitration catalyst layer, and the plurality of gas mixers are provided. A technology relating to a denitration apparatus is described in which ammonia injection nozzles are divided and arranged corresponding to each of the above, and the ammonia injection amount is variable for each nozzle.

  Since nitrogen oxides and ammonia react at a molar ratio of 1: 1, reducing the nitrogen oxide concentration at the inlet of the denitration apparatus can reduce the amount of ammonia consumption and the operating cost of the plant.

  Japanese Patent Laid-Open No. 5-33906 describes a technique for determining the flow rate of air supplied from a burner and an air port so that the set value of the oxygen concentration in the exhaust gas from the boiler outlet matches the measured oxygen concentration value. Yes. In addition, a technique is described in which the operating cost can be reduced by appropriately giving the set value of the oxygen concentration so that the unburned component in the boiler exhaust gas and the concentration of nitrogen oxides do not exceed the regulation values.

JP-A-9-75673 JP-A-5-33906

  The nitrogen oxide concentration distribution at the inlet of the denitration device varies depending on the distribution of the amount of air supplied from the burner and the air port. Therefore, depending on the air amount distribution conditions, the distribution of nitrogen oxide concentration at the inlet of the denitration apparatus may be biased, and the nitrogen oxide concentration may locally increase.

  If the amount of ammonia necessary to reduce the nitrogen oxides in this region exceeds the upper limit of the amount of ammonia that can be supplied from one ammonia injection nozzle, the nitrogen oxides in that region cannot be reduced and the nitrogen oxides cannot be reduced. The concentration may not decrease to the desired concentration.

  Further, the supplied ammonia cannot be reacted at all in the space where the nitrogen oxide concentration is high, and the remaining ammonia flows out downstream of the denitration apparatus. If ammonia flows out downstream of the denitration device, it not only causes clogging of the air heater, but also makes the situation undesirable for the surrounding environment.

  An object of the present invention is to reduce the concentration of nitrogen oxides in the exhaust gas discharged from the boiler to a desired value and to suppress the excess ammonia injected into the denitration device from flowing out downstream of the denitration device. It is providing the control apparatus of this, and the control method of a boiler.

The boiler control apparatus according to the present invention includes a burner that supplies fuel and air into the boiler, and a downstream side in the flow direction of the combustion gas generated by the combustion of the fuel and air supplied from the burner into the boiler. And a denitration device that removes nitrogen oxides contained in the combustion gas discharged from the boiler using a catalyst in the presence of ammonia, and is installed in the denitration device. Boiler for controlling the amount of air supplied from the burner or the air port of the apparatus provided with an ammonia injection nozzle for supplying ammonia to the combustion gas flowing into the denitration apparatus upstream, and the amount of ammonia injected from the ammonia injection nozzle In this control device, the boiler control device divides the inlet cross section of the denitration device into a plurality of regions, and the nitrogen oxide concentration is divided into each region. From the burner or the air port so that the nitrogen oxide concentration for each region satisfies the target condition of the nitrogen oxide concentration and the nitrogen oxide concentration at the inlet of the denitration device is low. An air amount determining means for determining an air amount to be supplied, and an ammonia amount determining means for determining an ammonia amount to be supplied from the ammonia injection nozzle based on a predicted value of a model for predicting a nitrogen oxide concentration distribution at the inlet of the denitration device And is provided.

  In the boiler control method of the present invention, fuel and air are supplied from the burner into the boiler, and the boiler on the downstream side in the flow direction of the combustion gas generated by burning the fuel and air supplied from the burner into the boiler is provided. A boiler that supplies air from an air port of the boiler, and a denitration device that removes nitrogen oxides contained in the combustion gas by using a catalyst in the presence of ammonia by injecting ammonia into the combustion gas discharged from the boiler In the boiler control method for controlling the amount of air supplied from the burner or air port of the apparatus and controlling the amount of ammonia supplied into the combustion gas, the boiler control method includes the denitration method. Nitrogen oxide concentration at the inlet of the previous denitration unit is set by setting the target condition of nitrogen oxide concentration for each of the divided areas. The amount of air supplied from the burner or the air port is determined so as to satisfy the target condition of the nitrogen oxide concentration, and the amount of air supplied from the burner or the air port is controlled. The amount of ammonia to be supplied is determined based on a predicted value based on a model for predicting the nitrogen oxide concentration distribution of the gas, and the amount of ammonia supplied into the combustion gas is controlled.

  According to the present invention, a boiler that reduces the concentration of nitrogen oxides in exhaust gas discharged from a boiler to a desired value and suppresses excess ammonia injected into the denitration apparatus from flowing out downstream of the denitration apparatus. The control apparatus and boiler control method can be realized.

  A boiler control device and a boiler control method according to an embodiment of the present invention will be described below with reference to the drawings.

  A boiler control apparatus and a boiler control method according to an embodiment of the present invention will be described below with reference to FIG.

  FIG. 1 is a schematic diagram showing the configuration of a boiler control apparatus according to an embodiment of the present invention.

  In FIG. 1, a boiler 1 is provided with a burner 2 for supplying pulverized coal serving as fuel and air, and an after-air port 3 for supplying air.

  The pulverized coal supplied from the burner 2 is combusted in the boiler 1 to generate high-temperature combustion gas. The pulverized coal is supplied to the burner 2 through the pulverized coal pipe 4, and the air is supplied to the burner 2 and the after-air port 3 through the air pipe 5.

  The heat exchanger 16 provided in the boiler 1 is supplied with water through a water supply pipe 14 provided with a water supply pump 15, and the water supplied in the heat exchanger 16 is hot combustion that flows down the boiler 1. It is heated by gas to become high temperature and high pressure steam.

  The high-temperature and high-pressure steam is supplied from the heat exchanger 16 to the steam turbine 17 to drive the steam turbine 17, and the generator 18 is rotated by the steam turbine 17 to generate electricity.

  The combustion gas generated by burning pulverized coal in the boiler 1 exchanges heat with the heat exchanger 16 as described above, and then enters the exhaust gas duct 19 disposed on the downstream side of the boiler 1. It flows into the denitration device 40 installed on the downstream side.

  A plurality of ammonia injection nozzles 10 and 11 are disposed in the exhaust gas duct 19 on the inlet side of the denitration apparatus 40.

  Mixers 8 and 9 are connected to the upstream sides of these ammonia injection nozzles 10 and 11, respectively.

  The mixer 8 is provided with an air pipe 13 and an ammonia pipe 12, and passes through the pressurized air supplied from the air pipe 13, the ammonia pipe 12 and the ammonia flow control valve 6. The supplied ammonia is mixed with the mixer 8.

  Ammonia mixed with pressurized air by the mixer 8 is supplied to the ammonia injection nozzle 11, and is ejected from the ammonia injection nozzle 11 into the exhaust gas duct 19 and flows into the downstream denitration device 40.

  Similarly, the mixer 9 is provided with an air pipe 13 and an ammonia pipe 12, and passes through the pressurized air supplied from the air pipe 13, the ammonia pipe 12 and the ammonia flow rate control valve 7. Then, the supplied ammonia is mixed in the mixer 9.

  Ammonia mixed with pressurized air in the mixer 9 is supplied to the ammonia injection nozzle 10, and is ejected from the ammonia injection nozzle 10 into the exhaust gas duct 19 and flows into the downstream denitration device 40.

  The plurality of ammonia flow rate control valves 6 and 7 installed in the ammonia pipe 12 are individually controlled by the operation signal 310 output from the control device 100, and the amount of ammonia supplied to the plurality of mixers 8 and 9. Are configured to be individually adjustable.

  Although not shown in the embodiment of FIG. 1, a plurality of burners 2 and after-air ports 3 are generally arranged in the boiler 1.

  An air flow rate control valve (not shown) is installed in the burner 2 installed in the boiler 1 and the air pipe 5 for supplying air supplied to the after-air port 3 so that the air amount can be adjusted. The opening degree of the control valve is also individually controlled by an operation signal 310 output from the control device 100.

  In this embodiment, the ammonia injection nozzles 10 and 11 in the exhaust gas duct 19, the mixers 8 and 9 outside the exhaust gas duct 19, and the ammonia flow rate control valves 6 and 7 are arranged at two locations, respectively. The number and the position to be arranged may be arbitrarily changed.

  It is also possible to install the mixers 8 and 9 in the exhaust gas duct 19 and arrange a partition plate in the exhaust gas duct 19 that divides the flow path of the combustion gas.

  In the boiler 1, various measuring instruments for measuring the state quantity of the boiler 1 are arranged in order to grasp the operation state of the boiler. For example, the fuel flow rate and the air flow rate supplied to the boiler 1 are respectively measured by the flow rate measuring device 20 installed in the pulverized coal pipe 4 and the 21 installed in the air pipe 5.

  Further, the nitrogen oxide concentrations at the inlet and outlet of the denitration device 40 are installed in the exhaust gas duct 19 on the outlet side of the denitration device 40 and the concentration measuring devices 30 and 31 installed in the exhaust gas duct 19 on the inlet side of the denitration device 40. Measured by the concentration measuring instruments 32 and 33, respectively.

  Each measured value 210 measured by these measuring instruments is transmitted to the external interface 200 of the control device 100. Although not shown in FIG. 1, various measuring instruments other than the measuring instrument described above are installed in the boiler 1. For example, the steam temperature, the combustion gas flow rate, the ammonia flow rate, and the like are also measured, and these values are all transmitted to the control device 100.

  The control device 100 includes a correction command parameter determination unit 500, an ammonia reference value calculation unit 600, an ammonia correction command value calculation unit 700, an ammonia flow rate control valve opening calculation unit 900, an air amount reference value calculation unit 1100, an air amount as an arithmetic unit. Correction command value calculation means 1200 and air amount adjustment valve opening calculation means 1300 are provided.

  The correction command parameter determination unit 500 includes an air amount determination unit 550 and an ammonia amount determination unit 560.

  In addition, the control device 100 has a measurement value database 400 and a correction command value calculation parameter database 800 as databases.

  The control device 100 further includes an external input interface 200 and an external output interface 300 as interfaces with the outside.

  Then, each measured value 210 measured by these measuring instruments is taken into the control device 1 via the external input interface 200.

  The measured value 210 taken into the external input interface 200 is transmitted from the external input interface 200 to the measured value database 400 as the measured value 101 and stored with the time. Also, the ammonia reference value calculating means 600 and the ammonia correction command value calculating means 600 are stored. The measurement value 101 is transmitted to the ammonia flow control valve opening calculation means 900, the air amount reference value calculation means 1100, the air amount correction command value calculation means 1200, and the air amount adjustment valve opening calculation means 1300. Yes.

  The air amount reference value calculation means 1100 calculates the air amount reference value 121 using the measurement value 101, and the air amount correction command value calculation means 1200 uses the measurement value 101 and the correction command parameter 120 to calculate the air amount correction command value. 122 is calculated.

  The adder 125 provided in the control device 100 adds the air amount reference value 121 and the air amount correction command value 122 to calculate the air amount request value 123.

  The air amount adjustment valve opening degree calculation means 1300 calculates the air amount adjustment valve opening degree command value 124 using the measured value 101 and the required air amount value 123.

  The air amount adjustment valve opening command value 124 is transmitted from the control device 100 to the boiler 1 via the external output interface 310, and operates the opening of a valve (not shown) that adjusts the air amount of the burner 2 and the after-air port 3. To do.

  In the air amount reference value calculation means 1100 and the air amount correction command value calculation means 1200, a plurality of burners 2 such as a total air amount supplied from the burner 2 and a total air amount supplied from the front of the boiler 1, and an after-air port 3 may be defined as one group, and the air amount for each group may be calculated.

  The ammonia reference value calculation means 600 calculates the ammonia reference value 107 using the measured value 101.

  The ammonia correction command value calculation means 700 calculates the ammonia correction command value 106 using the measured value 101 and the ammonia correction command parameter 105 stored in the correction command value calculation parameter database 800.

  The adder 108 provided in the control device 100 adds the ammonia reference value 107 and the ammonia correction command value 106 to calculate the ammonia required value 109.

  In the ammonia flow control valve opening calculation means 900, the ammonia flow control valve opening command value 110 of the ammonia flow control valves 6 and 7 is set so that the ammonia required value 109 and the ammonia measurement value included in the measurement value 101 coincide. calculate.

  The ammonia flow control valve opening command value 110 is transmitted from the control device 100 to the ammonia flow control valves 6 and 7 via the external output interface 300.

  The correction command parameter 103 stored in the correction command value calculation parameter database 800 is calculated and updated by the correction command parameter determination means 500.

  The correction command parameter determination unit 500 calculates the correction command parameter 103 using the measurement value 102 from the measurement value database 400 and the correction command parameter 104 from the correction command value calculation parameter database 800.

  In FIG. 1, all the arithmetic devices and databases are arranged inside the control device 100 of the ammonia flow control valve. However, a part of them is arranged outside so that signals can be transmitted and received via the network. Also good.

  FIG. 2 is an operation flowchart in the boiler control apparatus according to the present embodiment.

  As shown in FIG. 2, the operation flowchart in the control device 100 of the present embodiment is executed by combining Step 1000, Step 1010, Step 1020, Step 1030, Step 1040, Step 1050, Step 1060, and Step 1070.

  First, in step 1000, a measured value 210 obtained by measuring the operating state of the boiler 1 with a measuring instrument is taken into the external interface 200 of the control device 100.

  In step 1010, the ammonia reference value calculation means 600 and the air amount reference value calculation means 1100 of the control device 100 are operated, and the measured value 101 is transmitted from the external interface 200 to the ammonia reference value calculation means 600 and the air amount reference value calculation means 1100. Then, the ammonia reference value 107 and the air amount reference value 121 are respectively calculated.

  In step 1020, it is determined whether correction control is to be performed. The determination method can be arbitrarily designed. For example, when the boiler 1 is performing load change operation, when the burner pattern is switched, when the type of coal used as fuel is changed, when the soot blower is operated, when nitrogen is oxidized at the inlet of the denitration device Correction control can be performed when the object concentration is higher than the target value.

  When the correction control is performed, the process proceeds to step 1030. When the correction control is not performed, the process proceeds to step 1070.

  In step 1030, it is determined whether or not the correction command parameter is to be updated. If so, the process proceeds to step 1040 to update the parameter, and if not, the process proceeds to step 1050.

  In step 1050, the ammonia correction command value calculation means 700 and / or the air amount correction command value calculation means 1200 are operated, and the ammonia correction command value calculation means 700 saves the measured value 101 and the correction command value calculation parameter database 800. The ammonia correction command value 106 is calculated using the ammonia correction command parameter 105.

  Further, the air amount correction command value calculation means 1200 calculates the air amount correction command value 122 using the measured value 101 and the correction command parameter 120 stored in the correction command value calculation parameter database 800.

  In step 1060, the ammonia reference value 107 calculated by the ammonia reference value calculation means 600 and the ammonia correction command value 106 calculated by the ammonia correction command value calculation means 700 are added by the adder 108 to calculate the ammonia required value 109. Thereafter, the ammonia flow control valve opening calculation means 900 is operated to calculate the ammonia flow control valve opening command value 110.

  The adder 125 adds the air amount reference value 121 calculated by the air amount reference value calculating means 1100 and the air amount correction command value 122 calculated by the air amount correction command value calculating means 1200 to add the required air amount value. 123 is calculated, and then the air flow rate control valve opening degree calculation means 1300 is operated to calculate the air flow rate control valve opening degree command value 124.

  In step 1070, the ammonia flow control valve opening command value 110 calculated by the ammonia flow control valve opening calculation means 900 in step 1060 and / or the air amount control valve opening calculated by the air amount control valve opening calculation means 1300. In accordance with the command value 124, the ammonia flow rate control valves 6, 7 for adjusting the flow rate of ammonia supplied to the ammonia injection nozzles 10, 11 disposed in the exhaust gas duct 19 of the boiler 1 via the external interface 300, and / or the boiler 1 And a valve (not shown) for adjusting the amount of air supplied to the burner 2 and the after-air port 3 through the air pipe 5 arranged in the above.

  Thereafter, the process returns to step 1000 and the same operation is repeated.

  FIG. 3A is an example of a control logic diagram in the ammonia reference value calculation means 600 provided in the control device 100 of the present embodiment, and FIG. It is one Example of the control logic figure of the degree calculation means 900.

  3C is an example of a control logic diagram of the air amount reference value calculation means 1100 provided in the control device 100, and FIG. 3D is an air amount adjustment valve opening degree provided in the control device 100. FIG. 10 is an example of a control logic diagram of the calculation means 1300.

  FIG. 3C is a control logic diagram for calculating the reference value of the total air amount supplied from the burner 2 of the boiler 1.

  In the multiplier 610 constituting the control logic of the ammonia reference value calculation means 600 provided in the control device 100 of the present embodiment shown in FIG. 3A, one of the measured values 101 obtained by measuring the state quantity of the boiler 1 is used. The NOx amount 603 is calculated by multiplying a certain combustion gas flow rate 601 and the inlet NOx concentration 602 of the denitration device 40.

  Further, the multiplier 620 constituting the control logic of the ammonia reference value calculation means 600 multiplies the NOx amount 603 and the molar ratio set value 604 to calculate the ammonia reference value 107 that is the output of the ammonia reference value calculation means 600. Thereby, the reference value of the ammonia amount necessary for reducing the inlet NOx of the denitration device 40 is calculated.

  In the adder / subtractor 910 constituting the control logic of the ammonia flow control valve opening degree calculation means 900 provided in the control device 100 of the present embodiment shown in FIG. 3B, the adder 108 uses the ammonia reference value 107 and the ammonia correction command. The ammonia deviation 902 is calculated by subtracting the ammonia measurement value 901 that is one of the measurement values 101 obtained by measuring the state quantity of the boiler 1 from the ammonia request value 109 calculated by adding the value 106.

  Further, the PI controller (proportional integral controller) 920 constituting the control logic of the ammonia flow control valve opening calculation means 900 uses the ammonia deviation 902 to output ammonia as the output of the ammonia flow control valve opening calculation means 900. A flow control valve opening command value 110 is calculated.

  The PI controller 920 operates to determine the ammonia flow control valve opening command value 110 so that the ammonia deviation 902 approaches zero.

  In the adder / subtractor 1110 constituting the control logic of the air amount reference value calculation means 1100 provided in the control device 100 of the present embodiment shown in FIG. 3C, the state quantity of the boiler 1 is measured from the oxygen concentration set value 1102. The oxygen concentration measurement value 1103 which is one of the measurement values 101 is subtracted to calculate an oxygen concentration deviation 1104.

  The PI controller 1120 that constitutes the control logic of the air amount reference value calculation means 1100 uses the oxygen concentration deviation 1104 to calculate the oxygen concentration correction value 1105.

  In an adder 1140 constituting the control logic of the air amount reference value calculation means 1100, the total air amount set value 1101 calculated based on the required output to the boiler 1 and the oxygen concentration correction value 1105 are added and input to the boiler 1. The total air amount command value 1106 that is the total amount of air to be calculated is calculated.

  Thereby, the air flow rate required for the oxygen concentration at the outlet of the boiler 1 to coincide with the oxygen concentration set value is calculated.

  Further, the gain 1130 constituting the control logic of the air amount reference value calculating means 1100 multiplies the total air amount command value 1106 by a certain value (0.8 in FIG. 10A) to obtain the air amount reference value calculating means 1100. The air quantity reference value 121 supplied from the burner 2 serving as the output of is calculated.

  In the adder / subtractor 1310 constituting the control logic of the air amount adjusting valve opening calculating means 1300 provided in the control device 100 of this embodiment shown in FIG. 3D, the adder 125 uses the air amount reference value 121 and the air amount. An air amount deviation 1302 is calculated by subtracting an air amount measurement value 1301 which is one of the measurement values 101 obtained by measuring the state amount of the boiler 1 from the air amount request value 123 calculated by adding the correction command value 122.

  Further, the PI controller 1320 constituting the control logic of the air amount adjusting valve opening calculating means 1300 uses the air amount deviation 1302 to output the air amount adjusting valve opening 1300 as an output of the air amount adjusting valve opening calculating means 1300. The command value 124 is calculated.

  The PI controller 1320 operates to determine the ammonia flow rate control valve opening command value 124 so that the air amount deviation 1302 approaches zero.

  Next, the air amount correction command value calculation means 1200 provided in the control device 100 of this embodiment will be described. In the air amount correction command value calculation means 1200, the air amount reference value output from the air amount reference value calculation means 1100 in order to reduce harmful substances such as nitrogen oxides and carbon monoxide contained in the exhaust gas discharged from the boiler 1. An air amount correction command value 122 for adjusting the value 121 is calculated.

  The correction command parameter determining means 500 provided in the control device 100 calculates a correction command parameter 120 necessary for calculating the air amount correction command value 122.

  The air amount determination means 550 provided in the correction command parameter determination means 500 provided in the control device 100 determines the amount of air supplied to the boiler 1 using an optimization method such as reinforcement learning. The correction command parameter determining means 500 derives the correction command parameter 103 so that the determined air amount is supplied to the boiler 1, and the correction command parameter 120 is supplied via the correction command value calculation parameter database 800. The air amount correction command value 122 is input to the value calculation means 1200 and the air amount correction command value calculation means 1200 calculates the air amount correction command value 122.

  The detailed explanation of the reinforcement learning theory used in the air amount determination means 550 provided in the correction command parameter determination means 500 of the control device 100 is, for example, “Reinforcement Learning”, co-translation by Sadayoshi Mikami and Masaaki Minagawa, Morikita Publishing Co., Ltd., published on Dec. 20, 2000 ", only the concept of reinforcement learning will be explained here.

  FIG. 4 shows a concept of control based on reinforcement learning theory learned by the air amount determination means 550 provided in the correction command parameter determination means 500. In the concept of control based on this reinforcement learning theory, the learning means 510 outputs an operation command 501 to the control target 520, and the control target 520 operates according to the control command 501. At this time, the state of the controlled object 520 changes due to the operation according to the control command 501. A reward 502 is received from the controlled object 520, which is an amount indicating whether or not the changed state is desirable or not desirable for the learning means 510 and how much they are.

  Actually, the information received from the controlled object 520 is the state quantity of the controlled object 520, and the learning unit 510 generally calculates the reward 502 based on the information. Generally, the reward 502 is set so as to increase as it approaches a desirable state, and the reward 502 decreases as the state becomes undesirable.

  The learning unit 510 performs an operation by trial and error, and learns an operation method that maximizes the reward 502 (that is, approaches a desirable state as much as possible), so that an appropriate operation according to the state of the control target 520 is performed. (Control) logic is built automatically.

  The supervised learning theory needs to provide a success case as teacher data in advance, and is not suitable when there is no operation data in a new plant or when a phenomenon is complicated and a success case cannot be prepared in advance. On the other hand, reinforcement learning theory is classified as unsupervised learning, and is applicable to cases where the characteristics of the controlled object are not always clear because it has the ability to generate desirable operations on a trial and error basis. Have advantages.

  However, in order to learn only from the operation data of the plant, it is necessary to wait until the operation data necessary for learning is sufficiently accumulated, so that it takes a long time to exert the effect. In addition, since learning is performed through trial and error, there is a possibility that an undesired state of driving may occur, and in some cases, there may be a problem in terms of safety.

  Therefore, in the control device 100 of this embodiment, what operation signal is generated for the model provided in the air amount determination means 550 of the correction command parameter determination means 500 that simulates the boiler 1 that is the control target. Learn in advance whether is good.

  This model provided in the air amount determining means 550 simulates the structure of the boiler 1, and the combustion (reaction), gas flow, and heat transfer processes are numerically analyzed by a differential method, a finite volume method, a finite element method, and the like. Calculate using the method.

  Although it is desirable that the analysis accuracy of the numerical analysis is high, the present invention is not characterized by the analysis method, and the description of the numerical analysis method is omitted because the analysis method is not limited. However, the shape of the boiler 1 that is generally a calculation target is omitted. Is divided into calculation grids (mesh), and physical quantities in the grids are calculated.

  By numerical analysis using a model provided in the air amount determination means 550, the temperature of the combustion gas in the boiler 1, the concentration of the combustion gas component, the flow velocity of the combustion gas, the flow direction, and the like are output as calculation results. By this numerical analysis, phenomena under various operating conditions are calculated, and the concentrations of both the nitrogen oxide and carbon monoxide concentrations in the boiler 1 are calculated.

  The calculation result of the measurement position is calculated for each calculation grid (mesh) of the cross section. After the operation of the boiler 1 is started, the air amount determination unit 550 includes the measurement value 102 stored in the measurement value database 400 installed in the control device 100 so that the model characteristic matches the plant characteristic. You can also modify the model.

  In the control device of the present embodiment, the case where reinforcement learning is applied as an optimization method has been described. However, the correction command parameter determination unit 500 of the control device 200 is used by using another optimization algorithm such as an evolutionary calculation method. It can also be constructed.

  As described above, in reinforcement learning, an operation method for maximizing a reward is learned. Therefore, the reward design policy (reward calculation method) has a great influence on the learning result. For example, if the design is such that the reward increases as the nitrogen oxide concentration at the outlet of the boiler 1 is lower, it is possible to learn the operating conditions for lowering the nitrogen oxide concentration.

  By designing the reward in this way, the nitrogen oxide concentration can be reduced and the amount of ammonia used to reduce the nitrogen oxide is reduced, so that the operating cost of the boiler 1 can be reduced.

  In the boiler control apparatus 100 of the present embodiment, the reward design method is further devised for the reasons described below.

  The nitrogen oxide concentration distribution at the inlet of the denitration device 40 varies depending on the distribution of the amount of air supplied from the burner 2 and the air port 3 to the boiler 1. Therefore, depending on the air amount distribution conditions, the distribution of the nitrogen oxide concentration may be uneven, and the nitrogen oxide concentration may locally increase.

  If the amount of ammonia necessary to reduce the nitrogen oxide in the region where the concentration of nitrogen oxides locally increases exceeds the upper limit of the amount of ammonia that can be supplied from one ammonia injection nozzle, the nitrogen in that region There arises a problem that the oxides cannot be reduced and the regulation value is deviated.

  Further, the supplied ammonia cannot be reacted at all in the denitration device 40, and the remaining ammonia may flow into an air heater installed on the downstream side of the denitration device 40.

  In order to avoid these phenomena, it is necessary to adjust the distribution of air supplied from the burner 2 of the boiler 1 and the after-air port 3 so that the nitrogen oxide concentration distribution at the inlet of the denitration apparatus 40 is not biased.

  Therefore, in the boiler control apparatus of the present embodiment, the reward is designed in consideration of not only the total amount of nitrogen oxides but also the distribution of nitrogen oxide concentration.

  FIG. 5 is an explanatory diagram illustrating a reward design method that takes into account the distribution of nitrogen oxide concentration at the inlet cross section of the denitration apparatus 40 in the present embodiment.

  As shown in the left part of FIG. 5, the inlet cross section of the denitration apparatus 40 is divided into a plurality of regions, in this embodiment, a total of 16 regions of 4 vertical and 4 horizontal, and the target of the nitrogen oxide concentration for each region Set the value.

  Setting of the target value of the nitrogen oxide concentration for each region is performed by an operator inputting the correction command value calculation parameter database 800 of the control device 100 of FIG. 1 from the outside.

  In the NOx concentration target value shown in the left part of FIG. 5, the NOx concentration is displayed slightly higher in a total of four sections from the center of the inlet cross section of the denitration device 40 to the vertical two sections and the two horizontal sections. Is set to a slightly higher value.

  Although not shown in FIG. 1, the control device 100 is provided with an interface for inputting a target value of the nitrogen oxide concentration from the outside for each inlet region of the denitration device 40. By using the operator, the target value of the nitrogen oxide concentration for each region can be input to the correction command value calculation parameter database 800.

  Further, the target value of the nitrogen oxide concentration can be automatically determined based on the spray range and spray amount of ammonia supplied from the ammonia injection nozzles 10 and 11 disposed in the exhaust gas duct 19. That is, based on the maximum spray amount and spray range that can be supplied from one ammonia injection nozzle 10, 11 and the maximum amount of nitrogen oxide that can be removed by the denitration device 40, the nitrogen oxide concentration at the outlet of the denitration device 40 is The target condition of nitrogen oxide at the inlet of the denitration apparatus 40 is determined so as to obtain a desired concentration.

  Next, the nitrogen oxide concentration distribution at the inlet of the denitration apparatus 40 is estimated based on the operating condition of the air flow rate in the air amount determination means 550 provided in the correction command parameter determination means 500. Finally, the error between the target value and the estimated value of the nitrogen oxide concentration is calculated for each region of the inlet of the denitration device 40, and the reward increases as the error decreases.

  In the operation example a shown in the upper right part of FIG. 5, in the NOx concentration in the cross section of the inlet of the denitration apparatus 40, one section is vertically divided from the center of the center of the inlet section of the denitration apparatus 40 and one section is laterally right. There is a region where the nitrogen oxide concentration is locally high so that the NOx concentration is displayed particularly densely in the area of the division, and since the error from the target value is large in this region where the nitrogen oxide concentration is high, the reward value is small.

  On the other hand, in the operation example b shown in the lower right part of FIG. 5, in the NOx concentration in the cross section of the inlet of the denitration apparatus 40, a total of 4 sections of 2 sections vertically and 2 sections from the center of the center of the inlet section of the denitration apparatus 40 Since the difference between the target value and the estimated value is smaller than that in the operation example a so that the segment area displays the NOx concentration slightly higher, the reward is increased.

  In the air amount determination means 550 installed in the correction command parameter determination means 500 of the control device 100 of the present embodiment, the reward that increases as the total amount of nitrogen oxides decreases and the reward described in FIG. And calculate the reward used for reinforcement learning.

  By calculating the above-described reward, it is possible to learn the distribution of the supply air so that the distribution of the nitrogen oxide concentration is close to the target value while the total amount of nitrogen oxide is small. As a result of this learning, the operation condition of the supply air amount that obtains the result of the NOx concentration distribution as shown in the operation example b of FIG. 5 is learned.

  In FIG. 5, the cross section of the inlet of the denitration apparatus is divided into 4 × 4 = 16 regions, but the number of divisions is arbitrary. In FIG. 5, the entire region is divided equally, but there may be a portion where the division is coarse and a portion where the division is coarse.

  FIG. 6 is an explanatory diagram for explaining an example of an estimation method for estimating the nitrogen oxide concentration distribution at the inlet cross section of the denitration apparatus 40 in the present embodiment in the air amount determination means 550 installed in the correction command parameter determination means 500. .

  As shown in FIG. 6, in this embodiment, denitration is performed by inputting the load, the time after the soot blower, the coal type, the burner pattern, the fuel flow rate, and the air flow rate to the air amount determination unit 550 installed in the correction command parameter determination unit 500. A neural network that predicts the nitrogen oxide concentration in each region obtained by dividing the inlet cross section of the device 40 into a plurality of areas is constructed.

  The weight parameter of the neural network of the air amount determining means 550 is stored in the relationship between the input and output of the neural network, the nitrogen oxide concentration is calculated using numerical analysis, and the measured value database 400 of the control device 100 is stored. Adjust to match the existing information.

  In this embodiment, the neural network is used for estimating the nitrogen oxide concentration, but the nitrogen oxide concentration for each region may be estimated using other methods.

  FIG. 7 shows a denitration apparatus that accompanies a load change, which is obtained in a trial and error process of reinforcement learning that is learned by the air amount determination means 550 provided in the correction command parameter determination means 500 installed in the control apparatus 100 of the present embodiment. It is explanatory drawing explaining the change of nitrogen oxide concentration distribution in an inlet_port | entrance.

In the thermal power plant provided with the boiler 1 of the present embodiment, load change operation is performed in which the output is changed according to the power demand. FIG. 7 (a), has been described an example of an output process of change, operated at an output M ₁ until time T _1, to increase the subsequent output to M _2, the output at time T ₃ has reached the M ₂ An example of fixing the output to M ₂ later is shown.

FIG. 7 (b) uses the model of the air amount determination means 550 provided in the correction command parameter determination means 500 to estimate the nitrogen oxide concentration at the inlet section of the denitration apparatus at times T ₁ , T ₂ , and T ₃ . As a result, the target value of the nitrogen oxide concentration distribution is shown in the left column, and the estimated value of the nitrogen oxide concentration distribution in the operation examples A and B is shown in the right column.

In FIG. 7 (b), the total amount of time _{T 1,} T 2, _{T 3} nitrogen oxides Operation Example A and the operation example B in is the same. In this case, in the learning using the reward using only the total amount of nitrogen oxides as an index, the superiority or inferiority of the operation example A and the operation example B cannot be obtained.

At each of the times T ₂ and T ₃ , in the operation example A, the nitrogen oxide concentration distribution has a local concentration bias, but in the operation example B, the nitrogen oxide concentration distribution has a local concentration increase. There is no. Therefore, the operation example B is a preferable operation method.

  In the control device 100 of the present embodiment, the air amount determining means 550 provided in the correction command parameter determining means 500 is used with a reward considering the nitrogen oxide concentration distribution in the inlet cross section of the denitration apparatus 40 described in FIG. learn.

In the air amount determination means 550, as shown in FIG. 7B, a target value of the nitrogen oxide concentration distribution in each region obtained by dividing the inlet cross section of the denitration device 40 into a plurality of times is set at each time. Then, in this air amount determination means 550, the total sum of rewards that is the difference from the target values calculated at the times T ₁ , T ₂ , T ₃ using the set target value of the nitrogen oxide concentration distribution is maximized. Learn how to operate.

  In the air amount determination means 550, as shown in FIG. 7B, since the reward value of the operation example B is larger than that of the operation example A, the operation method of the air flow rate when the result of the operation example B is obtained. Can learn.

  The learning result learned by the air amount determination means 550 is stored in the correction command value calculation parameter database 800 of the control device 100 of this embodiment.

  The air amount command value calculation means 1200 of the control device 100 uses the correction command parameter 120 stored in the correction command value calculation parameter database 800 to use the air amount supplied from the burner 2 and the after air port 3 of the boiler 1. However, the air amount correction value 122 is calculated so as to satisfy the operation condition obtained by the above-described learning. Above, description of the air quantity command value calculation means 1200 is complete | finished.

  Next, the ammonia correction command value calculation means 700 of the control device 100 will be described.

  The ammonia correction command value calculation means 700 adjusts the ammonia reference value 107 output from the ammonia reference value calculation means 600 in order to reduce nitrogen oxides contained in the exhaust gas discharged from the boiler 1 and reduce the ammonia outflow amount. The ammonia correction command value 106 to be calculated is calculated.

  The correction command parameter determination unit 500 of the control device 100 calculates a correction command parameter 120 necessary for calculating the air amount correction command value 122 output from the air amount correction command value calculation unit 1200.

  The ammonia amount determining means 560 provided in the correction command parameter determining means 500 determines the ammonia amount to be injected into the inlet of the denitration apparatus 40 from the ammonia injection nozzles 10 and 11 disposed in the exhaust gas duct 19.

  As shown in the control device 100 of FIG. 1, the ammonia flow rate injected from the ammonia injection nozzles 10 and 11 into the inlet of the denitration device 40 is the ammonia reference value 107 calculated by the ammonia reference value calculation means 600 and the ammonia correction control command calculation. This is determined using the ammonia correction value 106 calculated by the means 700.

  The ammonia reference value 107 calculated by the ammonia reference value calculation means 600 is calculated using the measured value of the NOx removal unit inlet NOx concentration as shown in FIG.

  The measured value of the NOx concentration at the inlet of the denitration apparatus is delayed by the time for collecting the combustion gas for analyzing the concentration of nitrogen oxides. Also, after operating the ammonia flow control valves 6, 7 installed in the ammonia pipes 12, 13, until ammonia is actually injected from the ammonia injection nozzles 10, 11 into the inlet of the denitration device 40, ammonia storage equipment To the denitration device 40 through the ammonia pipes 12 and 13.

  Therefore, when the nitrogen oxide concentration distribution at the inlet of the denitration device 40 changes, such as when the load is changing, even if the ammonia flow rate control valves 6 and 7 are controlled based on the ammonia reference value 107, the amount of ammonia is excessive. A shortage problem arises.

  In this case, the NOx concentration discharged from the system through the flue of the boiler 1 or the outflow amount of ammonia increases. In order to suppress this, the control apparatus 100 of the present embodiment includes an ammonia correction command value calculation means 700 that corrects the ammonia required value in advance.

  FIG. 8 is a diagram for explaining the operation contents and effects of the ammonia correction command value calculation means 700 of the control device 100.

  FIG. 8A is a diagram for explaining an example of the output changing method, and since it is the same diagram as FIG. 7A, its explanation is omitted.

  FIG. 8B is a cross-sectional view of the exhaust gas duct 19. As shown in FIG. 1, the concentration measuring devices 30 and 32 and the ammonia injection nozzle 10 are arranged in the upper part of the exhaust gas duct 19, and the concentration measuring devices 31 and 33 and the ammonia injection nozzle 11 are arranged in the lower part of the exhaust gas duct 19.

  8C and 8D show the nitrogen oxide concentration at the inlet of the denitration apparatus 40 and the nitrogen oxide at the outlet of the denitration apparatus 40 when the output is changed as shown in FIG. 8A. It is explanatory drawing which shows a time-dependent change of the density | concentration and the flow volume of ammonia supplied from the ammonia injection nozzles 10 and 11. FIG.

  FIG. 8C shows an example in which the ammonia correction control command calculation means 700 is not functioned in the control device 100 of this embodiment, and FIG. 8D shows the control device 100 of this embodiment. This is an example when the ammonia demand value 109 is calculated using the correction control command calculation means 700.

First, to describe the concentration of nitrogen oxides in the top outlet of the denitrator 40, In FIG. 8 (c), between the time T ₁ of the medium load change of T _3, the nitrogen oxides concentration in the top outlet of denitrator 40 Indicates a situation where the limit value is exceeded.

Therefore the use of ammonia correction control instruction calculating unit 700 installed in the control device 100 of the present embodiment as shown in FIG. 8 (d), the ammonia flow diagram between of T ₃ from the time T ₁ of the in load change More than in the case of 8 (c) (dotted line in FIG. 8 (d)).

  This shows that nitrogen oxides can be reduced and the concentration of nitrogen oxides at the upper outlet of the denitration apparatus 40 is suppressed below the limit value as indicated by the solid line.

  Next, the nitrogen oxide concentration at the lower outlet of the denitration apparatus 40 will be described.

In FIG. 8 (c), the nitrogen oxides concentration in the lower outlet of denitrator 40 is lower between the time T ₁ of the medium load change of T _3.

  In this time zone, the ammonia flow rate is relatively higher than that of nitrogen oxide, and ammonia is excessive. In such a case, excess ammonia flows into the air heater on the downstream side of the denitration device 40, causing clogging of the air heater.

Therefore the use of ammonia correction control instruction calculating unit 700 installed in the control device 100 of the present embodiment as shown in FIG. 8 (d), the ammonia flow diagram between of T ₃ from the time T ₁ of the in load change As shown by the solid line in FIG. 8C (dotted line in FIG. 8D), the amount of excess ammonia can be suppressed from flowing into the air heater.

  Thus, in the control device 100 of the present embodiment, the ammonia flow rate supplied from the ammonia flow rate control valves 6 and 7 can be individually operated, and the ammonia correction command value 106 can also be set individually.

  As an effect thereof, the nitrogen oxide concentration in the entire region in the inlet cross section of the denitration apparatus 40 can be suppressed to a limit value or less even during load change. Furthermore, surplus ammonia can be prevented from flowing into the air heater, and the air heater can be prevented from being clogged.

  FIG. 9 is a diagram illustrating a calculation example of the ammonia correction command value 106 during a load change output from the ammonia correction command value calculation means 700 installed in the control device 100 of the present embodiment.

  FIG. 9 is a relationship diagram of the elapsed time from the start of load change and the value of the ammonia correction command value 106 calculated and output by the ammonia correction command value calculation means 700.

9, the flow rate of the ammonia correction command value 106 to time _{X 3} zero, then increases from the time _{X 3} to flow _{X 1} by the time _{X 4.} The flow rate is maintained at X ₁ from time X ₄ to time X ₅ , and then decreased to flow rate X ₂ from time X ₅ to time X ₆ . Maintaining the flow rate from the time _{X 6} to time _{X 7} to _{X 2,} then, reducing the flow rate from the time _{X 7} to time _{X 8} to zero.

The correction command value parameter database 800 stores values from the flow rates X _{1 to} X ₂ and the times X _{3 to} X ₈ , and the ammonia correction command value calculation means 700 refers to these values while referring to these values. The value 106 is calculated.

  In the correction command parameter database 800, ammonia correction command parameters 105 are stored in correspondence with boiler operating conditions such as load change rate, load change width, coal type, burner pattern, and the like. That is, ammonia can be supplied in accordance with the change in nitrogen oxide concentration not only during load change operation but also during charcoal type switching and burner pattern switching.

  In the ammonia correction command value calculation means 700, the operation condition of the boiler 1 is grasped from the measured value 101, the correction command parameter corresponding to this is acquired from the correction command value calculation parameter database 800, and the ammonia correction command value 106 is calculated. .

Although FIG. 9 shows an example in which the ammonia correction command value 106 is calculated using eight correction command parameters of flow rates X _{1 to} X ₂ and times X _{3 to} X ₈ , the number of correction command parameters can be arbitrarily changed. The ammonia correction command value 106 having a more complicated shape than that in FIG. 9 can also be calculated.

  In FIG. 9, the ammonia correction command value 106 is increased or decreased linearly (straight line), but the ammonia correction command value 106 may be increased or decreased using a function such as a quadratic curve.

  The correction command parameters stored in the correction command value calculation parameter database 800 installed in the control device 100 of this embodiment can be set in advance by an operator. Further, the correction command parameter can be automatically adjusted using the correction command parameter determining means 500.

  FIG. 10 is a diagram for explaining an embodiment in which the correction command parameter determining means 500 installed in the control device 100 of the present embodiment determines the initial value of the correction command parameter stored in the correction command value calculation parameter database 800. .

  In the ammonia amount determination means 560 installed in the correction command parameter determination means 500, the nitrogen oxide concentration at the outlet of the denitration device 40 does not exceed the limit value based on the estimation result of the nitrogen oxide concentration at the inlet of the denitration device 40. The amount of ammonia required to make

  The correction command parameter determining means 500 determines the initial value of the correction command parameter so that this ammonia amount is supplied. Hereinafter, a description will be given with reference to FIG.

  In the ammonia amount determining means 560, first, using the calculation result of the NOx concentration distribution at the inlet of the denitration apparatus 40 shown in FIG. 5B, as shown in FIG. Predict changes in nitrogen oxide concentration over time.

  Next, based on the prediction result of the temporal change in the nitrogen oxide concentration in the upper and lower portions of the exhaust gas duct 19 shown in FIG. 10 (a), the ammonia amount determining means 560, as shown in FIG. 10 (b), Calculate the ammonia flow required to reduce the nitrogen oxides.

  Next, as shown in FIG. 10C, the expected value of the ammonia reference value is calculated by the ammonia reference value calculation means 600 based on the logic diagram shown in FIG.

  In addition, the curve shown with the dotted line in FIG.10 (c) is the same curve as the curve shown with the continuous line in FIG.10 (b).

  Then, in the ammonia amount determining means 560 of the correction command parameter determining means 500, as shown in FIG. 10 (d), the curve shown by the solid line in FIG. 10 (b) to the curve shown by the solid line in FIG. 10 (c). Then, the curve of the ammonia correction value 106 that is the difference between the two is subtracted, and the ammonia correction parameter is determined based on the curve of the ammonia correction value 106.

  FIG. 11 is a diagram illustrating a method for determining the ammonia correction command parameter 105 in the correction command parameter determination means 500 installed in the control device 100 of the present embodiment.

  The correction command parameter determination means 500 adjusts the ammonia correction command parameter in two steps. First, in the first step, the change characteristics of the nitrogen oxide concentration at the inlet and outlet of the denitration device 40 are predicted based on the operating conditions of the boiler 1.

  Next, in the second step, the correction command parameter is determined and updated so that the nitrogen oxide concentration at the outlet of the denitration apparatus 40 is not more than the limit value.

  Thus, the correction command parameter determination means 500 installed in the control device 100 of the present embodiment predicts the nitrogen oxide concentration at the inlet of the denitration device 40 and corrects ammonia in advance using this prediction result.

  FIG. 11A is an explanatory diagram of the first step of adjusting the ammonia correction command parameter by the correction command parameter determining means 500.

  As shown in FIG. 11A, the correction command parameter determination means 500 of this embodiment inputs the load, the load change rate, the load change width, the time after the soot blower, the coal type, the burner pattern, the fuel flow rate, and the air flow rate. As described above, a neural network that predicts the change characteristics of the nitrogen oxide concentration in each region in which the inlet of the denitration apparatus 40 is divided into a plurality of regions is constructed.

  The weight parameter of this neural network is adjusted so that the relationship between input and output matches the nitrogen oxide concentration with the calculation result using numerical analysis and the information stored in the measurement value database 400.

  In the correction command parameter determining means 500 of this embodiment, the neural network is used for estimating the nitrogen oxide concentration, but the nitrogen oxide concentration for each region may be estimated using other methods.

  FIG. 11B and FIG. 11C are explanatory diagrams of the second step of adjusting the ammonia correction command parameter by the correction command parameter determining means 500.

  The upper diagram in FIG. 11B is a graph showing the change over time of the ammonia correction command value, and the lower diagram in FIG. 11B is a graph showing the change over time in the nitrogen oxide concentration at the outlet of the denitration device 40 at that time. It is.

  As shown in the lower graph of 11 (b), the nitrogen oxide concentration at the outlet of the denitration apparatus 40 exceeds the limit value. In such a case, the correction command parameter determining means 500 updates the correction command parameter so that the ammonia correction command value increases as shown in FIG.

  Thereby, it is suppressed that the nitrogen oxide concentration at the outlet of the denitration apparatus 40 exceeds the limit value.

  Although not shown in FIG. 1, the control device 100 of the present embodiment and the image display device are connected so that signals used in the control device 100 and database information are displayed on the image display device. Can be configured.

  Thereby, the correction method of a correction command value parameter and the effect at the time of correction can be provided to a plant operator in an easy-to-understand manner.

  In the present embodiment, the method of automatically updating the correction command parameter by the correction command parameter determining means 500 has been described. However, the method of updating the correction command parameter is provided to the plant operator, and the operator manually operates with reference to this method. It is also possible to change the ammonia correction command parameter.

  According to the embodiment of the present invention, the concentration of nitrogen oxides in the exhaust gas discharged from the boiler is reduced to a desired value, and excess ammonia injected into the denitration device flows out to the downstream side of the denitration device. The boiler control device and the boiler control method can be realized.

  The present invention can be applied to a boiler control device and a boiler control method that are installed in a thermal power plant or the like and that burns fuel such as coal to generate working steam of the plant.

Schematic which shows the structure of the control apparatus of the boiler which is one Example of this invention. The operation | movement flowchart figure in the control apparatus of the boiler of a present Example shown in FIG. The control logic figure which respectively shows the ammonia reference value calculation means, the ammonia flow control valve opening calculation means, the air quantity reference value calculation means, and the air flow control valve opening calculation means in the control device of the present embodiment. Explanatory drawing which shows the concept of control by reinforcement learning theory. Explanatory drawing of the design method of the reward which considered distribution of the nitrogen oxide concentration in the inlet cross section of the denitration apparatus in a present Example. Explanatory drawing of the estimation method of the nitrogen oxide concentration distribution in the inlet cross section of the denitration apparatus in a present Example. Nitrogen oxide concentration at the inlet cross section of the denitration device with load change obtained in the process of reinforcement learning learned by the air amount determination means provided in the correction command parameter determination means installed in the control device of this embodiment Explanatory drawing of distribution change. Explanatory drawing explaining the operation | movement content of the ammonia correction command value calculation means installed in the control apparatus of a present Example, and its effect. Explanatory drawing of the example of calculation of the ammonia correction command value calculated with the ammonia correction command value calculation means installed in the control apparatus of a present Example. Explanatory drawing which determines the initial value of the correction command parameter preserve | saved in the parameter database for correction command value calculation in the correction command parameter determination means installed in the control apparatus of a present Example. Explanatory drawing which determines the ammonia correction command parameter in the correction command parameter determination means installed in the control apparatus of a present Example.

Explanation of symbols

  1: boiler, 2: burner, 3: after-air port, 4: piping for fuel (pulverized coal), 5: piping for air, 6: ammonia flow control valve, 7: ammonia flow control valve, 8: mixer, 9: Mixer, 10: ammonia injection nozzle, 11: ammonia injection nozzle, 12: ammonia piping, 13: air piping, 14: water supply piping, 15: water supply pump, 16: heat exchanger, 17: steam turbine, 18 : Generator, 19: exhaust gas duct, 20: flow meter, 21: flow meter, 30: concentration meter, 31: concentration meter, 32: concentration meter, 33: concentration meter, 40: denitration device, 100: control device, 200: external input interface, 210: measurement value, 300: external output interface, 310: operation signal, 400: measurement value database 500: correction command parameter determining means, 550: air amount determining means, 560: ammonia amount determining means, 600: ammonia reference value calculating means, 700: ammonia correction command value calculating means, 800: parameter database for calculating correction command values 900: Ammonia flow control valve opening calculating means, 1100: Air amount reference value calculating means, 1200: Air amount correction command value calculating means, 1300: Air amount adjusting valve opening calculating means.

Claims (7)

A boiler provided with a burner for supplying fuel and air into the boiler, and an air port for supplying air downstream in the flow direction of the combustion gas generated by combustion of the fuel and air supplied from the burner into the boiler; And a denitration device that removes nitrogen oxides contained in the combustion gas discharged from the boiler using a catalyst in the presence of ammonia, and the combustion flowing into the denitration device upstream of the denitration device In the control device of the boiler for controlling the amount of air supplied from the burner of the device in which the ammonia injection nozzle for supplying ammonia to the gas is disposed, or the amount of air supplied from the air port and the ammonia injection nozzle,
In the boiler control device, the inlet cross section of the denitration device is divided into a plurality of regions, and a target condition of nitrogen oxide concentration is set for each region, and the nitrogen oxide concentration in each region is the nitrogen oxide concentration. An air amount determining means for determining the amount of air supplied from the burner or the air port so that the concentration target condition is satisfied and the nitrogen oxide concentration at the inlet of the denitration device is lowered;
An boiler for determining the amount of ammonia to be supplied from the ammonia injection nozzle based on a predicted value of a model for predicting the nitrogen oxide concentration distribution at the inlet of the denitration device; Control device . In the boiler control device according to claim 1,
The air amount determination means has a smaller error between the model for predicting the nitrogen oxide concentration distribution at the inlet of the denitration apparatus, the target condition for the nitrogen oxide concentration, and the predicted value of the nitrogen oxide concentration distribution based on the model. A boiler control device comprising: learning means for determining an air amount that maximizes an evaluation value using reinforcement learning . In the boiler control device according to claim 1,
The target condition of the nitrogen oxide concentration is determined based on the maximum spray amount that can be supplied from the ammonia injection nozzle and the maximum amount of nitrogen oxide that can be removed by the denitration device. Equipment . In the boiler control device according to claim 1,
The boiler control device is provided with an interface for inputting a target condition of nitrogen oxide concentration for each region obtained by dividing the inlet cross section of the denitration device into a plurality of regions . A boiler that supplies fuel and air from the burner into the boiler, and supplies air from the boiler air port on the downstream side in the flow direction of the combustion gas generated by burning the fuel and air supplied from the burner into the boiler; Supplied from the burner or the air port of the apparatus equipped with a denitration device that injects ammonia into the combustion gas discharged from the boiler and removes nitrogen oxides contained in the combustion gas using a catalyst in the presence of ammonia In the boiler control method of controlling the amount of air to be performed and controlling the supply amount of ammonia supplied into the combustion gas,
The boiler control method divides the cross section of the inlet of the denitration apparatus into a plurality of areas and sets a target condition of nitrogen oxide concentration for each of the divided areas. The amount of air supplied from the burner or the air port is determined so as to satisfy the target condition of the nitrogen oxide concentration, the amount of air supplied from the burner or the air port is controlled, and the nitrogen oxide at the inlet of the denitration device is further controlled. A boiler control method, comprising: determining an ammonia amount to be supplied based on a predicted value based on a model for predicting a concentration distribution; and controlling the ammonia amount to be supplied into the combustion gas . In the boiler control method according to claim 5,
In determining the amount of air supplied from the burner or the air port, the nitrogen oxide concentration for each region divided into a plurality of regions using a predicted value based on a model predicted by the nitrogen oxide concentration distribution at the inlet of the denitration device. A method for controlling a boiler, comprising: using reinforcement learning to determine an air amount based on an evaluation value that increases as an error between a target condition of the model and a predicted value of a nitrogen oxide concentration distribution according to the model decreases . In the boiler control method according to claim 6,
The target condition of the nitrogen oxide concentration set for each of the divided regions is the maximum supply amount of ammonia that can be supplied into the combustion gas flowing into the denitration device, and the maximum amount of nitrogen oxides that can be removed by the denitration device. The control method of the boiler characterized by determining based on .

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