Boiler control device, boiler control method, and program

Abstract

To maintain stable operation during change of a required load to a boiler, regardless of an operating state of the boiler.SOLUTION: A boiler controller comprises an advance control signal generation unit, a correction coefficient calculation unit, and a control unit. The advance control signal generation unit generates an advance control signal based on load change of a boiler. The correction coefficient calculation unit calculates a correction coefficient for correcting the advance control signal based on at least one of the deviation of an index indicating an operating state of the boiler from a setting value, and a change rate or change acceleration of the index. The control unit controls the boiler based on the advance control signal corrected using a correction coefficient.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a boiler control device, a boiler control method, and a program. [Background technology]

[0002] Thermal power plants use boilers to burn fuel to generate steam to drive generators. In conventional base operation, boilers in thermal power plants are basically operated at rated output, and during times of reduced power demand, such as at night, the operating state is changed to reduce the load, thereby adjusting the output.

[0003] In such conventional boiler control, load changes are unidirectional toward the target load, but in order to prevent the boiler's operating state from becoming unstable due to a transient excess or deficiency of boiler input, a pre-control signal (BIR: Boiler Input Ratio) may be input to control parameters such as the amount of fuel input and the amount of superheater spray in response to a load change that is known in advance (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5970368 Summary of the Invention [Problem to be solved by the invention]

[0005] The amount of the advance control signal to be input is determined, for example, by a load change test performed during a trial run of the boiler. However, in a boiler that is actually in operation, the state may have changed since the trial run. In such a case, even if the advance control signal determined by the load change test during the trial run is input, the operating state of the boiler may become unstable when the load changes. For example, in a boiler that has started operation, the degree of superheat of the boiler outlet steam may be adjusted by removing soot and other particles adhering to the heat transfer surface at the appropriate time using a soot blower. If the amount of this superheat adjustment deviates from the set value during the trial run, the operating state of the boiler may not be stable even if the amount of advance control signal determined during the trial run is input.

[0006] In recent years, thermal power plants equipped with boilers are expected to play a role in adjusting fluctuations in power generation from renewable energy sources, which tend to fluctuate in power generation. In such applications, there are many opportunities for load changes in the boiler, and it is thought that the above-mentioned issues will also occur more frequently.

[0007] At least one embodiment of the present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a boiler control device, a boiler control method, and a program that can preferably achieve stable operation during changes in boiler load, regardless of the operating state of the boiler. [Means for solving the problem]

[0008] In order to solve the above problem, a boiler control device according to at least one embodiment of the present disclosure includes: an advance control signal generating unit for generating an advance control signal for the boiler based on a load change of the boiler; a correction coefficient calculation unit for calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; a control unit for controlling the boiler based on the advance control signal corrected using the correction coefficient; Equipped with.

[0009] In order to solve the above problem, a boiler control method according to at least one embodiment of the present disclosure includes: generating an advance control signal for the boiler based on a load change on the boiler; calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; controlling the boiler based on the preceding control signal corrected using the correction factor; Equipped with.

[0010] In order to solve the above problem, a program according to at least one embodiment of the present disclosure includes: Using a computer, generating an advance control signal for the boiler based on a load change on the boiler; calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; controlling the boiler based on the preceding control signal corrected using the correction factor; is possible. [Effects of the Invention]

[0011] According to at least one embodiment of the present disclosure, it is possible to provide a boiler control device, a boiler control method, and a program that can preferably achieve stable operation during a change in the boiler load, regardless of the operating state of the boiler. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of a boiler according to an embodiment. [Figure 2] 1 is a block diagram showing a hardware configuration of a boiler control device according to an embodiment. [Figure 3] 1 is a block diagram showing a functional configuration of a boiler control device according to one embodiment. [Figure 4] FIG. 4 is a control flow diagram of the advance control signal generating unit of FIG. 3. [Figure 5] FIG. 4 is a control flow diagram of a correction coefficient calculation unit in FIG. 3. [Figure 6] FIG. 10 is a diagram showing a typical transition of an advance control signal when the load change of the boiler is increasing. [Figure 7] 6 is an example of a function included in the first correction coefficient calculation unit of FIG. 5. [Figure 8] FIG. 10 is a diagram illustrating a calculation range of each correction coefficient in response to a change in deviation over time. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0014] First, a boiler that is a control target of a boiler control device according to some embodiments of the present disclosure will be described. Fig. 1 is a schematic configuration diagram of a boiler 10 according to one embodiment.

[0015] The boiler 10 is a boiler that uses a burner to burn pulverized solid fuel, which is the main fuel, and exchanges the heat generated by this combustion with feedwater or steam to generate superheated steam. Biomass fuel, coal, etc. are used as the solid fuel.

[0016] The boiler 10 has a furnace 11, a combustion device 20, and a combustion gas passage 12. The furnace 11 has a hollow rectangular cylindrical shape and is installed vertically. The furnace wall 101 that forms the inner wall surface of the furnace 11 is composed of multiple heat transfer tubes and fins that connect the heat transfer tubes together, and recovers the heat generated by the combustion of pulverized fuel by heat exchange with water and steam circulating inside the heat transfer tubes, while suppressing the temperature rise of the furnace wall 101.

[0017] The combustion device 20 is installed in the lower region of the furnace 11. In this embodiment, the combustion device 20 has a plurality of burners 21A, 21B, 21C, 21D, 21E, and 21F (hereinafter collectively referred to as "burners 21" where appropriate) attached to the furnace wall 101. The burners 21 are arranged at equal intervals along the circumferential direction of the furnace 11 (for example, four burners installed at each corner of the rectangular furnace 11) as one set, and are arranged in multiple stages along the vertical direction.

[0018] 1, for convenience of illustration, only two of one set of burners are shown, and each set is denoted by the reference numerals 21A, 21B, 21C, 21D, 21E, and 21F. The shape of the furnace, the number of burner stages, the number of burners per stage, the arrangement of the burners, etc. are not limited to this embodiment.

[0019] Burners 21A, 21B, 21C, 21D, 21E, and 21F are connected to a plurality of mills (pulverizers) 31A, 31B, 31C, 31D, 31E, and 31F (hereinafter, collectively referred to as "mills 31") via a plurality of pulverized fuel supply pipes 22A, 22B, 22C, 22D, 22E, and 22F (hereinafter, collectively referred to as "pulverized fuel supply pipes 22"), respectively. Mill 31 is, for example, a vertical roller mill having a pulverizing table (not shown) supported therein so as to be rotatable, and a plurality of pulverizing rollers (not shown) supported above the pulverizing table so as to be rotatable in conjunction with the rotation of the pulverizing table. The solid fuel pulverized by the cooperation of the pulverizing rollers and the pulverizing table is transported to a classifier (not shown) provided in mill 31 by primary air (carrier gas, oxidizing gas) supplied to mill 31. The classifier separates the pulverized fuel into pulverized fuel having a particle size smaller than that suitable for combustion in the burner 21 and coarse pulverized fuel having a particle size larger than that. The pulverized fuel passes through the classifier and is supplied to the burner 21 together with primary air via the pulverized fuel supply pipe 22. The coarse pulverized fuel that does not pass through the classifier falls onto the grinding table inside the mill 31 under its own weight and is re-ground.

[0020] An air register 23 is provided outside the furnace 11 at the installation position of the burner 21, and one end of an air duct 24 is connected to the air register 23. A forced draft fan (FDF) 32 is connected to the other end of the air duct 24. The air supplied from the forced draft fan 32 is heated by an air preheater 42 installed in the air duct 24 and is supplied to the burner 21 via the air register 23 as secondary air (combustion air, oxidizing gas) and introduced into the furnace 11.

[0021] The combustion gas passage 12 is connected to the vertical upper part of the furnace 11. The combustion gas passage 12 is provided with superheaters 102A, 102B, and 102C (hereinafter collectively referred to as "superheaters 102" as appropriate), reheaters 103A and 103B (hereinafter collectively referred to as "reheaters 103" as appropriate), and a coal economizer 104 as heat exchangers for recovering heat from the combustion gas, and heat is exchanged between the combustion gas generated in the furnace 11 and the feedwater or steam flowing inside each heat exchanger. The arrangement and shape of each heat exchanger are not limited to the form shown in FIG.

[0022] A flue 13 is connected to the downstream side of the combustion gas passage 12, and discharges the combustion gas whose heat has been recovered by the heat exchanger. An air preheater (air heater) 42 is provided between the flue 13 and the air duct 24, and heat is exchanged between the air flowing through the air duct 24 and the combustion gas flowing through the flue 13, heating the primary air supplied to the mill 31 and the secondary air supplied to the burner 21, thereby recovering further heat from the combustion gas after heat exchange with water and steam.

[0023] Furthermore, a denitration device 43 may be provided in the flue 13 at a position upstream of the air preheater 42. The denitration device 43 supplies a reducing agent, such as ammonia or urea water, which has the effect of reducing nitrogen oxides, to the combustion gas flowing through the flue 13, and promotes the reaction between the nitrogen oxides (NOx) in the combustion gas to which the reducing agent has been supplied and the reducing agent by the catalytic action of a denitration catalyst provided in the denitration device 43, thereby removing and reducing the nitrogen oxides in the combustion gas.

[0024] A gas duct 41 is connected to the flue 13 downstream of the air preheater 42. The gas duct 41 is provided with environmental equipment such as a dust collector 44, such as an electrostatic precipitator, that removes ash and the like from the combustion gas, and a desulfurization equipment 46 that removes sulfur oxides, as well as an induced draft fan (IDF) 45 that guides the exhaust gas to these environmental equipment. The downstream end of the gas duct 41 is connected to a chimney 47, and the combustion gas that has been treated in the environmental equipment is discharged to the outside of the system as exhaust gas.

[0025] In the boiler 10, when the multiple mills 31 are driven, pulverized and classified pulverized fuel is supplied to the burner 21 together with primary air via the pulverized fuel supply pipe 22. In addition, secondary air heated by the air preheater 42 is supplied to the burner 21 from the air duct 24 via the wind box 23. The burner 21 blows a pulverized fuel mixture, which is a mixture of pulverized fuel and primary air, into the furnace 11, and also blows secondary air into the furnace 11. The pulverized fuel mixture blown into the furnace 11 ignites and reacts with the secondary air to form a flame. A flame is formed in the lower region of the furnace 11, and high-temperature combustion gas rises within the furnace 11 and flows into the combustion gas passage 12. In this embodiment, air is used as the oxidizing gas (primary air, secondary air), but the oxidizing gas may have a higher or lower oxygen content than air, and stable combustion can be achieved in the furnace 11 by adjusting the ratio of the amount of oxygen to the amount of fuel supplied within an appropriate range.

[0026] The combustion gas that has flowed into the combustion gas passage 12 exchanges heat with water and steam in a superheater 102, a reheater 103, and a coal economizer 104, which are arranged inside the combustion gas passage 12, and is then discharged into the flue 13, where nitrogen oxides are removed in the denitration device 43, the combustion gas exchanges heat with primary air and secondary air in the air preheater 42, and is then discharged into the gas duct 41, where ash and the like are removed in the dust collector 44, and sulfur oxides are removed in the desulfurization device 46, and the combustion gas is then discharged to the outside of the system through a chimney 47. The arrangement of the heat exchangers in the combustion gas passage 12 and the devices from the flue 13 to the gas duct 41 does not necessarily have to be in the order described above with respect to the flow of combustion gas.

[0027] Next, a description will be given of a boiler control device 100 that controls the boiler 10 having the above configuration. Fig. 2 is a block diagram showing the hardware configuration of the boiler control device 100 according to one embodiment.

[0028] The boiler control device 100 is configured as an arithmetic processing device such as a computer. The hardware configuration of the boiler control device 100 includes an input unit 110, a storage unit 120, a calculation unit 130, and an output unit 140, as shown in FIG.

[0029] The input unit 110 is configured to input various information necessary for the calculation processing performed in the boiler control device 100. The input unit 110 may be a human interface such as a mouse, keyboard, or touch panel that can be operated by an operator, or an interface device for acquiring various information from other devices including the boiler 10 that is the object of control.

[0030] The storage unit 120 is configured to store various types of information necessary for the arithmetic processing performed in the boiler control device 100. The storage unit 120 is configured from a computer-readable storage medium including at least one of RAM (Random Access Memory) and ROM (Read Only Memory). The various types of information stored in the storage unit 120 include programs that enable these hardware configurations to function as the boiler control device 100.

[0031] The calculation unit 130 is configured to perform various calculations of the boiler control device 100, and includes, for example, a CPU (Central Processing Unit). The calculation unit 130 reads out the programs stored in the storage unit 120 into a RAM or the like and executes information processing and calculation processing, thereby realizing various functions of the boiler control device 100.

[0032] The program executed by the calculation unit 130 may be stored in the storage unit 120 as described above, or may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means, etc. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0033] The output unit 140 is configured to perform output based on the calculation result in the calculation unit 130. In this embodiment, the output unit 140 outputs a control signal to the boiler 10, which is the object of control, as the output of the boiler control device 100. By receiving the control signal, the boiler 10 is controlled based on the control signal.

[0034] In addition to outputting a control signal to the boiler 10 that is the object of control, the output unit 140 may also include a human interface such as a display for an operator to recognize the calculation results, or a notification means for issuing an alarm in accordance with the calculation results.

[0035] Next, a functional configuration of the boiler control device 100 will be described. Fig. 3 is a block diagram showing the functional configuration of the boiler control device 100 according to one embodiment. The boiler control device 100 includes a control unit 150, an advance control signal generation unit 160, and a correction coefficient calculation unit 170.

[0036] The block diagram shown in FIG. 3 is an example showing the functional configuration of the boiler control device 100 in accordance with the following description, and each block may be integrated with another or further subdivided.

[0037] The control unit 150 is configured to control the boiler 10 by generating a control signal corresponding to a control parameter of a control target based on an input parameter relating to the operating state of the boiler 10.

[0038] The advance control signal generating unit 160 is configured to generate an advance control signal (BIR: Boiler Input Ratio) for the control signal handled by the control unit 150. The advance control signal BIR is generated based on information regarding a known load change of the boiler, and is intended to prevent the boiler operating state from becoming unstable due to a transient excess or deficiency of boiler input (fuel supply amount, etc.) toward the target load. In this embodiment, as an example, the advance control signal BIR is generated based on a load index corresponding to the boiler load, a load change rate, and a load change width.

[0039] The correction coefficient calculation unit 170 is configured to calculate a correction coefficient AN for correcting the advance control signal BIR generated by the advance control signal generation unit 160. The correction coefficient AN calculated by the correction coefficient calculation unit 170 is used to correct the advance control signal BIR by being multiplied by the advance control signal BIR generated by the advance control signal generation unit 160, and the control unit 150 controls the boiler 10 based on the corrected advance control signal BIR.

[0040] Next, the control contents by the advance control signal generator 160 and the correction coefficient calculator 170 will be described in detail with reference to Fig. 4 and Fig. 5. Fig. 4 is a control flow diagram of the advance control signal generator 160 in Fig. 3, and Fig. 5 is a control flow diagram of the correction coefficient calculator 170 in Fig. 3.

[0041] 4, the advance control signal generator 160 receives as input parameters the load index, which is the control target value of the boiler load, the load change rate, which is the rate of change of the boiler load, and the load change width, which is the difference between the load at the start of the boiler load change and the load at the completion of the load change, to generate the advance control signal BIR. The behavior of the advance control signal BIR is determined by the target value BIRt and the change rate (speed of change). For example, in the case of a thermal power plant, the load index is the power generation command (MWD) for the plant. The load of the boiler is controlled using the power generation command as a control target value.

[0042] The behavior of a typical advance control signal BIR will now be described with reference to Fig. 6. Fig. 6 is a diagram showing the transition of a typical advance control signal BIR with a load change when the load on the boiler increases.

[0043] FIG. 6 shows a case in which the boiler load, which has an initial value L1, begins to increase at time t1 and reaches a target value L2 at time t2. At this time, the advance control signal BIR begins to increase from time t1 according to a first rate of change R1 (constant value) preset as the rate of change during the increase, and changes to reach the target value BIRt at time t3. Typically, time t3 is before time t2, and the advance control signal BIR, which reaches the target value BIRt at time t3, remains constant until time t2, when the boiler load change ends. Then, when the boiler load change ends at time t2, the advance control signal BIR gradually decreases from the target value BIRt to zero according to a second rate of change R2 (constant value) preset as the rate of change during the decrease. As a result, the advance control signal BIR becomes zero (initial value) at time t4. In this way, after time t2 when the boiler load reaches the target value L2 and the boiler operation is stabilized, the advance control signal BIR, which is input to stabilize the operating state during a change in the boiler load, is removed, thereby preventing the advance control signal BIR from becoming a disturbance.

[0044] 4, in the advance control signal generating unit 160, the load index, the load change rate, and the load change width, which are input parameters, are input to functions fx1, fx2, and fx3, respectively, and the outputs are multiplied to determine the target value BIRt of the advance control signal BIR. In particular, in this embodiment, the calculation results of these functions are further multiplied by a correction coefficient AN calculated by the correction coefficient calculating unit 170, so that the target value BIRt of the advance control signal BIR can be corrected.

[0045] In the advance control signal generator 160, the load indexes, which are input parameters, are input to functions fx4 and fx5, and a first change rate R1 and a second change rate R2 are calculated based on the respective calculation results. Based on the target value BIRt of the advance control signal BIR, the first change rate R1, and the second change rate R2 calculated in this way, the advance control signal generator 160 generates the advance control signal BIR so as to realize the behavior of the advance control signal BIR exemplarily described with reference to FIG.

[0046] 5, the correction coefficient calculation unit 170 includes a first correction coefficient calculation unit 172 for calculating a first correction coefficient AN1, a second correction coefficient AN2, and a third correction coefficient calculation unit 176 for calculating a third correction coefficient AN3. As described below, the first correction coefficient calculation unit 172, the second correction coefficient calculation unit 174, and the third correction coefficient calculation unit 176 calculate the first correction coefficient AN1, the second correction coefficient AN2, and the third correction coefficient AN3, respectively, based on the deviation ΔP of a parameter P indicating the operating state of the boiler 10 from a preset setting value, and calculate an integrated correction coefficient by multiplying the first correction coefficient AN1 by the second correction coefficient AN2 and the third correction coefficient AN3. If the integrated correction coefficient is equal to or less than an upper limit value described below, it is output as the correction coefficient AN. The parameter P indicating the operating state of the boiler 10 is not limited, but in this embodiment, as an example, the parameter P is the outlet steam superheat degree of the boiler 10. The steam superheat degree is defined as, for example, the difference between the steam temperature measured at a specific position (for example, the detected value of the steam temperature sensor 27a in FIG. 1) and the saturated temperature of the steam at the pressure at the steam temperature measurement position (for example, the detected value of the pressure sensor 27b in FIG. 1). The steam superheat degree is not limited to this definition as long as it is an index indicating the degree of superheat of steam.

[0047] The first correction coefficient calculation unit 172 is configured to calculate a first correction coefficient AN1 based on the deviation ΔP as the correction coefficient AN when the deviation ΔP is greater than a first reference value (threshold value ΔPref). The relationship between the deviation ΔP and the first correction coefficient AN1 is set in advance as a function fx6, and the first correction coefficient calculation unit 172 calculates the first correction coefficient AN1 corresponding to the deviation ΔP based on the function fx6.

[0048] 7 shows an example of the function fx6 included in the first correction coefficient calculation unit 172 shown in FIG. 5. In this example, the function fx6 is configured so that the first correction coefficient AN1 decreases stepwise as the deviation ΔP increases. Specifically, in the range of ΔP<ΔP1, the first correction coefficient AN1 is a constant value AN1a. In the range of ΔP1≦ΔP<ΔP2, the first correction coefficient AN1 monotonically decreases as the deviation ΔP increases. In the range of ΔP2≦ΔP<ΔP3, the first correction coefficient AN1 is a constant value AN1b. In the range of ΔP3≦ΔP<ΔP4, the first correction coefficient AN1 monotonically decreases as the deviation ΔP increases. In the range of ΔP4≦ΔP, the first correction coefficient AN1 is a constant value AN1c.

[0049] 5, the second correction coefficient calculation unit 174 has a deviation change rate calculation unit 175 for calculating the deviation change rate DP based on the deviation ΔP. The deviation change rate calculation unit 175 calculates the deviation change rate DP by differentiating the deviation ΔP with respect to time. The second correction coefficient calculation unit 174 is configured to output a second correction coefficient AN2 when the deviation change rate DP calculated in this manner is greater than a second reference value DPref.

[0050] Particularly in this embodiment, the second correction coefficient calculation unit 174 is configured to output the second correction coefficient AN2 when both of the following conditions are met: (i) the deviation ΔP is greater than a preset threshold value ΔPref (first reference value) (first condition), and (ii) the deviation change rate DP is greater than a second reference value DPref (second condition). Specifically, when at least one of the first condition and the second condition is not met, the second correction coefficient calculation unit outputs a default value of "1.0" (the set value stored in SG2 and SG4 in FIG. 5), and when both the first condition and the second condition are met, the switching unit 177 switches the output value of the second correction coefficient calculation unit 174 from the default value "1.0" to the second correction coefficient AN2.

[0051] The second correction coefficient AN2 is calculated based on a load index corresponding to the load of the boiler and at least one process value of the boiler 10. In this embodiment, the load index corresponding to the load of the boiler, and the first process value and the second process value acquired by a sensor or the like (not shown) are input to functions fx7 to fx9, respectively, and the output results of the functions fx7 to fx9 are multiplied to obtain the second correction coefficient AN2.

[0052] The first process value and the second process value used to calculate the second correction coefficient AN2 are, for example, the superheater outlet steam temperature deviation (difference from a preset steam temperature setpoint) in the boiler 10 and the opening of the superheater spray valve (a valve that adjusts the flow rate of spray water sprayed into the steam to adjust the steam temperature).

[0053] In addition, in FIG. 5, the second correction coefficient calculation unit 174 is shown as a second correction coefficient calculation unit 174a that corresponds to the case where the change in the deviation ΔP is in an increasing direction, and a second correction coefficient calculation unit 174b that corresponds to the case where the change in the deviation ΔP is in a decreasing direction. The configurations of both units are the same except that the determination thresholds for the first and second conditions described above are positive and negative.

[0054] The third correction coefficient calculation unit 176 has a deviation change acceleration calculation unit 178 for calculating a deviation change acceleration AP based on a load index corresponding to the load on the boiler. The deviation change acceleration calculation unit 178 calculates the deviation change acceleration AP (=(DP1-DP2)÷Δt) based on the deviation change rate DP1 at a specific time t calculated by the deviation change rate calculation unit 175 and the deviation change rate DP2 after a certain time Δt has elapsed since the time t. The third correction coefficient calculation unit 176 is configured to output a third correction coefficient AN3 when the deviation change acceleration AP calculated in this manner is equal to or greater than a third reference value APref.

[0055] Particularly in this embodiment, the third correction coefficient calculation unit 176 is configured to output the third correction coefficient AN3 when all of the following conditions are met: (iii) the deviation change acceleration AP is greater than the third reference value APref (third condition), in addition to the above-mentioned first and second conditions used in the second correction coefficient calculation unit 174. Specifically, when at least one of the first to third conditions is not met, the third correction coefficient calculation unit 176 outputs a default value of "1.0," and when all of the first to third conditions are met, the switching unit 179 switches the output value from the third correction coefficient calculation unit 176 from the default value "1.0" (the set value stored in SG3 and SG5 in FIG. 5) to the third correction coefficient AN3.

[0056] The third correction coefficient AN3 is calculated based on a load index corresponding to the load of the boiler and at least one process value of the boiler 10. In this embodiment, the load index corresponding to the load of the boiler and the first process value and the second process value acquired by a sensor or the like (not shown) are input to functions fx10 to fx12, respectively, and the third correction coefficient AN3 is calculated by multiplying the output results of the functions fx10 to fx12.

[0057] The first process value and the second process value used to calculate the third correction coefficient AN3 are, for example, the superheater outlet steam temperature deviation and the superheater spray valve opening degree in the boiler 10. The first process value and the second process value used to calculate the third correction coefficient AN3 may be the same as or different from the first process value and the second process value used to calculate the above-mentioned second correction coefficient AN2.

[0058] In addition, in FIG. 5, the third correction coefficient calculation unit 176 is shown as a third correction coefficient calculation unit 176a that corresponds to the case where the change in the deviation ΔP is in an increasing direction, and a third correction coefficient calculation unit 176b that corresponds to the case where the change in the deviation ΔP is in a decreasing direction. The configurations of both are the same except that the judgment thresholds for the first to third conditions described above are positive or negative.

[0059] FIG. 8 is a diagram showing the calculation ranges of each correction coefficient with respect to a change in the deviation ΔP over time. The first correction coefficient AN1 is calculated in a range A where the deviation ΔP is larger than the first reference value ΔPref (in this case, the first correction coefficient calculation unit 172 outputs a first correction coefficient AN1 that is not the default value "1.0"). The second correction coefficient AN2 is calculated in a range B where the deviation change rate DP is larger than the second reference value DPref (in this case, the second correction coefficient calculation unit 174 outputs a second correction coefficient AN2 that is not the default value "1.0"). The third correction coefficient AN3 is calculated in a range C where the deviation change acceleration AP is larger than the third reference value APref (in this case, the third correction coefficient calculation unit 176 outputs a third correction coefficient AN3 that is not the default value "1.0").

[0060] In this way, the first correction coefficient AN1 to the third correction coefficient AN3 are output in the ranges A to C, respectively. In particular, in the range where the ranges A and B overlap, the first correction coefficients AN1 and AN2 indicate values ​​other than the default value "1.0," so the advance control signal BIR is corrected by a correction coefficient AN including the first correction coefficient AN1 and the second correction coefficient AN2 (the first correction coefficient AN1 multiplied by the second correction coefficient AN2). Furthermore, in the range where the ranges A to C overlap, the first correction coefficient AN1, the second correction coefficient AN2, and the third correction coefficient AN3 indicate values ​​other than the default value "1.0," so the advance control signal BIR is corrected by a correction coefficient AN including the first correction coefficient AN1, the second correction coefficient AN2, and the third correction coefficient AN3 (the first correction coefficient AN1 multiplied by the second correction coefficient AN2 and the third correction coefficient AN3).

[0061] As shown in Fig. 5, the correction coefficient calculation unit 170 further includes a correction coefficient limiting unit 180 for limiting the correction coefficient AN to a preset upper limit during a load change. The correction coefficient limiting unit 180 is configured to detect the start of a boiler load change based on a change in the boiler load index, etc., and, using this as a trigger, compare the integrated correction coefficient obtained by multiplying the first correction coefficient AN1, the second correction coefficient AN2, and the third correction coefficient AN3 with an upper limit value (the set value "2.0" stored in SG1 in Fig. 5), and output the smaller one as the final correction coefficient AN. By limiting the correction coefficient AN to a preset upper limit value in this way, it is possible to effectively prevent the correction coefficient AN from becoming excessively large during a load change, thereby preventing the boiler from becoming unstable in operation.

[0062] As described above, according to the above embodiment, the correction coefficient AN for the advance control signal BIR is calculated based on the deviation ΔP from the set value of the index indicating the operating state of the boiler 10. As a result, even if the operating state of the boiler 10 has changed since the trial run when the various set values ​​were determined, stable boiler operation can be achieved by correcting the advance control signal BIR using the correction coefficient AN based on the deviation ΔP that indicates the state of the change (degree and direction of change). In particular, by calculating the correction coefficient AN based on at least one of the rate of change DP or the change acceleration AP of the index in addition to the deviation ΔP, better stability can be achieved compared to when the correction coefficient AN is simply calculated based only on the deviation ΔP.

[0063] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0064] The contents described in each of the above embodiments can be understood, for example, as follows.

[0065] (1) A boiler control device according to one aspect includes: an advance control signal generator (160) for generating an advance control signal (BIR) for the boiler (10) based on a load change of the boiler; a correction coefficient calculation unit (170) for calculating a correction coefficient (AN) for correcting the advance control signal based on a deviation (ΔP) of an index indicating the operating state of the boiler from a set value, and at least one of a rate of change (DP) or an acceleration of change (AP) of the index; a control unit (150) for controlling the boiler based on the advance control signal corrected using the correction coefficient; Equipped with.

[0066] According to the above aspect (1), a correction coefficient for the advance control signal is calculated based on the deviation of an index indicating the operating state of the boiler from a set value. As a result, even if the operating state of the boiler has changed since the trial run, stable boiler operation can be achieved by correcting the advance control signal using a correction coefficient based on the deviation indicating the state of the change. In particular, by calculating the correction coefficient based on at least one of the rate of change or the acceleration of change of the index in addition to the deviation, better stability can be achieved compared to when the correction coefficient is calculated simply based on the deviation alone.

[0067] (2) In another embodiment, in the above embodiment (1), The correction coefficient calculation unit a first correction coefficient calculation unit (172) for calculating a first correction coefficient (AN1) based on the deviation as the correction coefficient when the deviation is greater than a first reference value; a second correction coefficient calculation unit (174) for calculating a second correction coefficient (AN2) based on the rate of change as the correction coefficient when the rate of change is greater than a second reference value; a third correction coefficient calculation unit (176) for calculating a third correction coefficient (AN3) based on the change acceleration as the correction coefficient when the change acceleration is greater than a third reference value; Includes.

[0068] According to the above aspect (2), the first correction coefficient, the second correction coefficient, and the third correction coefficient corresponding to the deviation, the rate of change, and the change acceleration, respectively, are calculated as correction coefficients for correcting the advance control signal.

[0069] (3) In another embodiment, in the above embodiment (2), The first correction coefficient is calculated using a first function that defines the relationship between the deviation and the first correction coefficient.

[0070] According to the above aspect (3), the advance control signal is corrected using the first correction coefficient obtained by inputting the deviation into the first function as the correction coefficient.

[0071] (4) In another aspect, in the above aspect (2) or (3), The second correction coefficient is calculated based on a load index corresponding to a load of the boiler and at least one process value of the boiler.

[0072] According to the above aspect (4), the advance control signal is corrected using, as the correction coefficient, the second correction coefficient calculated based on the load index and at least one process value.

[0073] (5) In another embodiment, in any one of the above (2) to (4), The third correction coefficient is calculated based on a load index corresponding to a load of the boiler and at least one process value of the boiler.

[0074] According to the above aspect (5), the advance control signal is corrected using, as the correction coefficient, the third correction coefficient calculated based on the load index and at least one process value.

[0075] (6) In another embodiment, in any one of the above (1) to (5), The engine further includes a correction coefficient limiting unit for limiting the correction coefficient to a preset upper limit value or less when the load changes.

[0076] According to the above aspect (6), by limiting the correction coefficient to a value equal to or less than a preset upper limit value, it is possible to effectively prevent the boiler operation from becoming unstable due to the correction coefficient becoming excessive during a load change.

[0077] (7) In another embodiment, in any one of the above (1) to (6), The index is the degree of steam superheat at the outlet of the boiler.

[0078] According to the above aspect (7), the correction coefficient is calculated based on a deviation using the degree of superheat of the steam at the outlet of the boiler superheater as an index. As a result, even if the degree of superheat has changed since the test run due to, for example, contamination of the heat transfer surface or the operating state of the soot blower, stable boiler operation can be achieved by controlling the boiler based on the advance control signal corrected by the correction coefficient.

[0079] (8) A boiler control method according to one aspect includes: generating an advance control signal for the boiler based on a load change on the boiler; calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; controlling the boiler based on the preceding control signal corrected using the correction factor; Equipped with.

[0080] According to the above aspect (8), a correction coefficient for the advance control signal is calculated based on the deviation of an index indicating the operating state of the boiler from a set value. As a result, even if the operating state of the boiler has changed since the trial run, stable boiler operation can be achieved by correcting the advance control signal using a correction coefficient based on the deviation indicating the change. In particular, by calculating the correction coefficient based on at least one of the rate of change or the acceleration of change of the index in addition to the deviation, better stability can be achieved compared to when the correction coefficient is calculated simply based on the deviation alone.

[0081] (9) A program according to one aspect includes: Using a computer, generating an advance control signal for the boiler based on a load change on the boiler; calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; controlling the boiler based on the preceding control signal corrected using the correction factor; is possible.

[0082] According to the above aspect (9), a correction coefficient for the advance control signal is calculated based on the deviation of an index indicating the operating state of the boiler from a set value. As a result, even if the operating state of the boiler has changed since the trial run, stable boiler operation can be achieved by correcting the advance control signal using a correction coefficient based on the deviation indicating the change. In particular, by calculating the correction coefficient based on at least one of the rate of change or the acceleration of change of the index in addition to the deviation, better stability can be achieved compared to when the correction coefficient is calculated simply based on the deviation alone. [Explanation of symbols]

[0083] 10. Boiler 11 Furnace 12 Combustion gas passage 13 Flue 20 Combustion equipment 21 Burner 22 Fine fuel supply pipe 23 Wind Box 24 Wind road 31 mil 32 Forced draft fan 41 Gas duct 42 Air preheater 43 Denitration equipment 44 Dust collection device 46 Desulfurization equipment 47 Chimney 100 Boiler control device 101 Furnace wall 102 Superheater 103 Reheater 104 Economizer 110 Input section 120 Storage section 130 Arithmetic section 140 Output section 150 control section 160 Advance control signal generator 170 Correction coefficient calculation unit 172 First correction coefficient calculation unit 174 Second correction coefficient calculation unit 175 Deviation change rate calculation unit 176 Third correction coefficient calculation unit 177 Switching section 178 Deviation change acceleration calculation unit 179 Switching section 180 Correction coefficient limiting section AN correction factor

Claims

1. an advance control signal generating unit for generating an advance control signal for the boiler based on a load change of the boiler; a correction coefficient calculation unit for calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; a control unit for controlling the boiler based on the advance control signal corrected using the correction coefficient; Equipped with The correction coefficient calculation unit a first correction coefficient calculation unit for calculating, as the correction coefficient, a first correction coefficient based on the deviation when the deviation is greater than a first reference value; a second correction coefficient calculation unit for calculating, as the correction coefficient, a second correction coefficient based on the change rate when the change rate is greater than a second reference value; a third correction coefficient calculation unit for calculating, as the correction coefficient, a third correction coefficient based on the change acceleration when the change acceleration is greater than a third reference value; A boiler control device comprising:

2. The boiler control device according to claim 1 , wherein the first correction coefficient is calculated using a first function that defines a relationship between the deviation and the first correction coefficient.

3. The boiler control device according to claim 1 or 2, wherein the second correction coefficient is calculated based on a load index corresponding to a load of the boiler and at least one process value of the boiler.

4. The boiler control device according to claim 1 , wherein the third correction coefficient is calculated based on a load index corresponding to a load of the boiler and at least one process value of the boiler.

5. The boiler control device according to claim 1 , further comprising a correction coefficient limiting unit that limits the correction coefficient to a preset upper limit value or less when the load changes.

6. The boiler control device according to claim 1 , wherein the indicator is a degree of steam superheat at an outlet of the boiler.

7. An advance control signal generating unit for generating an advance control signal for the boiler based on a load change of the boiler; a correction coefficient calculation unit for calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; a control unit for controlling the boiler based on the advance control signal corrected using the correction coefficient; Equipped with A boiler control device, wherein the indicator is a degree of steam superheat at an outlet of the boiler.

8. generating an advance control signal for the boiler based on a load change on the boiler; calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; controlling the boiler based on the preceding control signal corrected using the correction factor; Equipped with In the step of calculating the correction coefficient, If the deviation is greater than a first reference value, a first correction coefficient based on the deviation is calculated as the correction coefficient; When the rate of change is greater than a second reference value, a second correction coefficient based on the rate of change is calculated as the correction coefficient; When the change acceleration is greater than a third reference value, a third correction coefficient based on the change acceleration is calculated as the correction coefficient.

9. Using a computer, generating an advance control signal for the boiler based on a load change on the boiler; calculating a correction coefficient for correcting the advance control signal based on a deviation of an index indicating the operating state of the boiler from a set value and at least one of a rate of change or an acceleration of change of the index; controlling the boiler based on the preceding control signal corrected using the correction factor; is executable, In the step of calculating the correction coefficient, If the deviation is greater than a first reference value, a first correction coefficient based on the deviation is calculated as the correction coefficient; When the rate of change is greater than a second reference value, a second correction coefficient based on the rate of change is calculated as the correction coefficient; When the change acceleration is greater than a third reference value, a third correction coefficient based on the change acceleration is calculated as the correction coefficient.

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