JP6894503B2 - Boiler combustion control system and boiler combustion control method - Google Patents

Description

The present invention relates to a technique for controlling combustion of a boiler, and more particularly to a boiler combustion control system for determining a fuel input amount to a boiler based on a load requirement of the boiler, and a technique effective when applied to a boiler combustion control method. It is a thing.

For example, when acquiring energy using a boiler facility, fuel (solid fuel, liquid fuel, or gaseous fuel) is supplied to the boiler (fire furnace) and burned, and the heat is absorbed by a heat exchanger to absorb steam. Generate and obtain heat energy. The generated steam is converted from thermal energy into rotary motion by supplying it to a steam turbine, for example, and is used for power generation by a generator or the like. The amount of fuel input to the boiler is the load requirement (for example, the power generation requirement MWD (Mega Watt Demand), which may be referred to as the load requirement MWD below) and the fuel input to the boiler (hereinafter). Then, it is determined by the fuel function FX, which is a relational expression between the boiler input command value (may be described as BID (Boiler Input Demand)).

Here, the operating state of the boiler, particularly the main vapor pressure, may fluctuate due to the influence of various factors related to the boiler equipment, such as fuel properties, calorific value, furnace dirt, suit blower, and air / water temperature. Therefore, the fuel related to the fuel input amount obtained by the fuel function FX is supplied to the boiler, the generated main steam pressure is measured, and the PID (Proportional-) is based on the difference between this and the preset main steam pressure. Integral-Differential) control is generally used to obtain the feedback correction amount and add it to the load request amount to correct the fuel input amount to the boiler.

As a technique related to this, for example, in Japanese Patent No. 4522326 (Patent Document 1), a plurality of values are stored while sequentially updating the ratio or difference between the values before and after the feedback correction, and the stored values are used. It is described that the fuel correction coefficient is obtained and the value after feedback correction is corrected by this correction coefficient. As a result, it is possible to correct the fuel input amount to an appropriate level in consideration of changes in the thermal efficiency of the boiler due to the influence of various factors.

Further, for example, in Japanese Patent No. 4791269 (Patent Document 2), in a plurality of types of fuel mixed combustion boiler, the fuel correction coefficient for correcting the value after feedback correction is subdivided into three elements to obtain the fuel. It is stated that the amount of fuel input to the boiler is corrected in response to the difference in unit calorific value and the difference in boiler thermal efficiency due to changes in the co-firing rate.

Japanese Patent No. 4522326 Japanese Patent No. 4791269

For example, according to the prior arts such as Patent Documents 1 and 2, the value (or other control value) of the load required amount MWD before and after the feedback correction is compared at any time with respect to the change in the thermal efficiency of the boiler due to the influence of various factors. This can be determined by measurement, and the value of the correction coefficient for further correcting and optimizing the value after feedback correction based on the determination result can be obtained by self-learning.

On the other hand, the fuel function FX, which defines the relationship between the load request amount MWD and the corresponding boiler input command value BID as a function (curve), is set by reflecting the characteristics of the boiler, and in the prior art, it is set. , It is set as a fixed value calculated in advance based on the accumulation of past actual measurement data. However, the behavior of the main vapor pressure based on the characteristics of the boiler is different for each boiler, and even one boiler can be changed by updating the boiler equipment or the like. That is, there may be a slight discrepancy between the actual behavior of the main vapor pressure and the ideal value (optimal value) assumed in the fuel function FX. This deviation causes a deviation from the optimum value of the fuel input amount, destabilizes the combustion control process of the boiler, and results in energy loss.

Therefore, an object of the present invention is a boiler combustion control system that can detect a deviation from the optimum value assumed by the fuel function FX in the behavior of the main vapor pressure and modify the fuel function FX autonomously and self-sufficiently. , And to provide a boiler combustion control method.

The above and other objects and novel features of the present invention will become apparent from the description and accompanying drawings herein.

A brief description of typical inventions disclosed in the present application is as follows.

In the boiler combustion control system according to a typical embodiment of the present invention, fuel related to the fuel input amount to the boiler calculated based on a predetermined fuel function with respect to the load required amount is supplied to the boiler and measured. The feedback correction amount is obtained based on the measured main steam pressure which is the main steam pressure of the boiler and the set main steam pressure which is the main steam pressure of the boiler set in advance, and the load is based on the feedback correction amount. A boiler combustion control system that outputs a fuel correction coefficient for correcting the load requirement amount or the fuel input amount after the feedback correction to a plant that corrects the required amount or the fuel input amount, and is a boiler combustion control system for the feedback correction. A fuel for which the fuel correction coefficient is calculated based on the ratio of the load demand before and after and the initial value and the fine adjustment function that define the initial value of the relationship between the load demand and the fuel input amount for the boiler. It has a correction coefficient calculation unit and a reference curve correction unit that outputs a reference curve correction coefficient that corrects the initial value and the fine adjustment function.

Then, the reference curve correction unit includes a deviation determination unit that calculates the deviation between the measurement main steam pressure and the set main steam pressure, a cycle determination unit that acquires and records a cycle related to the fluctuation of the deviation, and the cycle determination unit. An amplitude determination unit that acquires and records the amplitude related to the fluctuation of the deviation, a reference curve correction coefficient output unit that calculates and outputs the reference curve correction coefficient based on a predetermined reference curve correction function, and the period and the amplitude. A reference curve fuel function correction determination unit that determines whether or not the combination of the above conditions satisfies a predetermined condition, and corrects the reference curve correction function based on the control state for the boiler when the conditions are satisfied. Have.

Among the inventions disclosed in the present application, the effects obtained by representative ones will be briefly described as follows.

That is, according to a typical embodiment of the present invention, the deviation from the optimum value assumed by the fuel function FX in the behavior of the main vapor pressure is detected, and the fuel function FX is autonomously and self-contained. Is possible.

It is a figure which showed the outline about the structural example of the boiler combustion control system which concerns on Embodiment 1 of this invention. It is a figure which showed the outline about the structural example of the reference curve correction part in Embodiment 1 of this invention. It is a flow figure which showed the example of the flow of the process which corrects the initial value and a fine adjustment function in Embodiment 1 of this invention. It is the figure which showed the outline about the example of the behavior of the main vapor pressure. It is a figure which showed the outline about the structural example of the boiler combustion control system which concerns on Embodiment 2 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in all the drawings for explaining the embodiment, in principle, the same reference numerals are given to the same parts, and the repeated description thereof will be omitted. On the other hand, the parts described with reference numerals in one figure may be referred to with the same reference numerals in the explanation of other figures, although they are not shown again.

(Embodiment 1)
As described above, when energy is acquired using the boiler equipment, the fuel (for example, coal, biomass fuel, etc.) input amount (boiler input command value BID) corresponding to the steam requirement amount (load request amount MWD) of the boiler is determined. , Determined using the fuel function FX. At this time, the load request amount MWD is controlled so as to perform feedback correction so as to bring the main vapor pressure of the boiler closer to the desired set main vapor pressure.

On the other hand, in the prior art as described in Patent Documents 1 and 2 above, in order to further improve the control accuracy, the ratio of the load required amount MWD before and after the feedback correction, that is, the feedback of the main vapor pressure. The fuel correction coefficient is obtained by self-learning based on an index indicating the degree of operation of correction, and the load required amount MWD (or boiler input command value BID) is further corrected by this fuel correction coefficient. It can be said that this correction is substantially equivalent to correcting the fuel function FX.

In the boiler combustion control system according to the first embodiment of the present invention, in order to further improve the accuracy with respect to the above-mentioned conventional technique, the reference curve which is the basis / starting point of self-learning is corrected by AI (Artificial Intelligence). Is what you do. This reference curve shows the initial value of the relationship between the load request amount MWD specified for the target boiler and the boiler input command value BID. In the prior art, this reference curve is set as a fixed value calculated in advance based on the accumulation of past actual measurement data, similarly to the fuel function FX. In this case, the behavior of the main vapor pressure deviates slightly from the optimum value assumed in the fuel function FX corrected by the fuel correction coefficient due to the equipment update of the boiler or other changes in the state, and the combustion control of the boiler is performed. The process may become unstable and efficiency may decrease.

On the other hand, in the boiler fuel control system of the present embodiment, the behavior / state change of the main vapor pressure of the boiler is constantly analyzed / determined based on the past data, and the above reference curve is adjusted based on the determination result. By doing so, a slight deviation occurring in the fuel function FX is corrected. Then, in the present embodiment, this series of processing is performed autonomously and in real time by a self-contained processing loop.

<System configuration>
FIG. 1 is a diagram showing an outline of a configuration example of a boiler combustion control system according to a first embodiment of the present invention. As described above, the boiler combustion control system 1 determines the fuel correction coefficient K by adjusting the reference curve using the initial value and the fine adjustment function FXAI so that the fuel input amount to the boiler 2 in the plant is optimized. This is a device that outputs control information to an existing circuit or the like that inputs fuel to the boiler 2 (that is, controls combustion of the boiler 2 by substantially correcting the fuel function FX).

The boiler combustion control system 1 may be configured as, for example, a device implemented by hardware including a semiconductor circuit (not shown), a microcomputer, or the like that executes processing related to each function described later. Alternatively, it is configured by a general-purpose server device, a virtual server built on a cloud computing service, etc., and is deployed on memory from a recording device such as an HDD (Hard Disk Drive) by a CPU (Central Processing Unit) (not shown). By executing middleware such as an OS (Operating System) or software running on the middleware, processing related to each function described later may be executed.

Further, the hardware implementation and the software implementation may be appropriately combined and configured. Further, the configuration is not limited to the configuration in which the whole is mounted in one housing, and a configuration in which some functions are mounted in another housing and these housings are connected to each other by a communication cable or the like may be used. That is, the mounting form of the boiler combustion control system 1 is not particularly limited, and it can be appropriately and flexibly configured according to the environment of the plant and the like.

As shown in the figure, the boiler combustion control system 1 includes, for example, a division unit 11, a reference curve correction unit 12, a multiplication unit 13, a fuel correction coefficient calculation unit 14, and the like implemented by hardware or software. In addition, it has data such as a file recorded in a memory, an HDD, etc., an initial value implemented as a table, and a fine adjustment function FXAI.

In the plant, the main steam generated by burning the fuel in the boiler 2 based on the information of the fuel input amount (boiler input command value BID in the figure) is supplied to the steam turbine 3, for example, by a generator (not shown). Used for power generation, etc. The load request amount MWD (input steam request amount) of the boiler 2 corresponding to the output of the generator is input by, for example, an operation panel (not shown) of the boiler 2 and is also input to the boiler combustion control system 1.

On the other hand, for example, the pressure of the main steam generated in the boiler 2 is measured by a pressure gauge (not shown) provided in the boiler 2, and the measured value is input to the main steam pressure transmitter PX. The measured main vapor pressure PV transmitted from the main vapor pressure transmitter PX is input to the PID control unit 4, and is compared with the set main vapor pressure SV which is the main vapor pressure that should be originally in the PID control unit 4. Be struck. At this time, for example, if the fuel input amount is determined using the fuel function FX obtained under the conditions where the state of the boiler 2 (dirt of the furnace, etc.), fuel properties, and other factors are maintained, the measurement is performed. There is almost no difference between the main vapor pressure PV and the set main vapor pressure SV, and the desired load (generator output) can be obtained by the fuel function FX. However, as described above, for example, a pressure difference may occur between the measured main vapor pressure PV and the set main vapor pressure SV due to changes in the state of the boiler 2, fuel properties, and other factors. is there.

When the PID control unit 4 detects the pressure difference between the measured main vapor pressure PV and the set main vapor pressure SV, it is generated by a feedback correction amount, that is, a fuel shortage (or excess) by a known PID control method. The deviation (error amount) of the main vapor pressure is calculated and sent to the adding unit 5. In the addition unit 5, the feedback correction amount sent from the PID control unit 4 is added to the load request amount MWD input to the boiler combustion control system 1, so that the load request amount MWD'(boiler input) after the feedback correction is added. The command value BID') is output (the PID control unit 4 and the addition unit 5 may be referred to as a feedback control unit).

In the boiler fuel control system 1 of the present embodiment, as described above, in order to follow the deviation from the optimum value due to the change in the characteristics such as the efficiency of the boiler 2 as in the prior arts such as Patent Documents 1 and 2. , An index indicating the degree of operation of the feedback correction by the feedback control unit (PID control unit 4 and the addition unit 5), that is, the load request amount MWD and the load request amount MWD'(boiler input command value) which are command values before and after the feedback correction. The ratio of BID') is obtained by the dividing unit 11. Then, using this as an input, the fuel correction coefficient calculation unit 14 calculates the fuel correction coefficient K by self-learning and outputs it.

The output fuel correction coefficient K is multiplied by the load request amount MWD'(boiler input command value BID') by the multiplication unit 6. This corrected load request amount MWD "(boiler input command value BID") is input, and the fuel input amount calculation unit 7 converts this into a boiler input command value BID by the fuel function FX. The injection of fuel into the boiler 2 is controlled based on the boiler input command value BID.

As for the method for calculating the fuel correction coefficient K in the fuel correction coefficient calculation unit 14 of the boiler combustion control system 1, for example, the same method as that described in Patent Documents 1 and 2 can be appropriately used. The detailed description here will be omitted again. Further, as described in Patent Documents 1 and 2, the connection relationship and processing order of each part of the plant including the boiler combustion control system 1 are not limited to those shown in FIG. 1, and are within the scope of the same idea. It is possible to appropriately adopt various variations of the configuration. For example, in the example of FIG. 1, the fuel correction coefficient K is multiplied by the load request amount MWD'after the feedback correction to be corrected, but it is multiplied by the boiler input command value BID obtained by the fuel input amount calculation unit 7. It may be configured to be corrected. Further, the fuel function FX may be directly corrected.

As described above, in determining the fuel correction coefficient K, self-learning is performed starting from the reference curve, but in the prior art, a preset fixed value is used for the reference curve. In this case, as the characteristics such as the efficiency of the boiler 2 change, the reference curve also deviates slightly from the optimum value, and the combustion control process of the boiler 2 may become unstable and the efficiency may decrease. Therefore, in the present embodiment, the reference curve correction unit 12 constantly performs comparative measurement between the measured main vapor pressure PV of the boiler 2 and the set main vapor pressure SV, which is the originally set value, to make the main steam pressure of the boiler 2 main. The change in the behavior of the vapor pressure is analyzed and judged, and the reference curve correction coefficient KP is set based on the judgment result. Then, by multiplying the initial value and the fine adjustment function FXAI by the multiplication unit 13, the initial value and the initial value of the reference curve defined in the fine adjustment function FXAI are corrected in real time.

FIG. 4 is a diagram showing an outline of an example of the behavior of the main vapor pressure. The figure of each stage shows an example of the fluctuation of the measured main vapor pressure PV with the passage of time by a curve, and also shows the set main vapor pressure SV by a straight line. The upper figure shows the case where the degree of correction (correction by fuel correction coefficient K and integral correction by PID control) is strongly set, and the measured main vapor pressure PV fluctuates greatly across the set main vapor pressure SV. It shows that it is. On the other hand, the middle figure shows the case where the degree of correction is optimum, and shows that the measured main vapor pressure PV fluctuates in the vicinity of the set main vapor pressure SV. On the other hand, the lower figure shows the case where the degree of correction is set to be weak, and the measured main vapor pressure PV fluctuates greatly and slowly across the set main vapor pressure SV as a whole while repeating small fluctuations. It is shown that.

Here, in the boiler combustion control system 1 of the present embodiment, the behavior of the main vapor pressure is centered on the vibration of the measured main vapor pressure PV based on the set main vapor pressure SV, that is, the set main vapor pressure SV. It is grasped by the amplitude and the period (the interval at which the measured main vapor pressure PV intersects the set main vapor pressure SV). The optimum state of the main vapor pressure (measured main vapor pressure PV) basically means a state in which the amplitude is small and the period is short, as shown in the middle figure. In addition, the state where the period is long means that the state where the measured main vapor pressure PV is separated from the set main vapor pressure SV continues for a long period of time as shown in the lower figure.

As described above, for example, if the fuel input amount is determined using the fuel function FX obtained under the condition that the state of the boiler 2, the fuel properties, and other factors are maintained, the measured main vapor pressure PV. There is almost no difference between the set main vapor pressure SV and the set main vapor pressure SV. Actually, for example, as shown in the middle figure of FIG. 4, the measured main vapor pressure PV vibrates with a small amplitude around the set main vapor pressure SV. However, a pressure difference (deviation) may occur between the measured main vapor pressure PV and the set main vapor pressure SV due to changes in the state of the boiler 2, fuel properties, and other factors. In the present embodiment, this deviation is measured to detect the timing when the measured main vapor pressure PV is in the optimum state, that is, the state in which the amplitude and period values are small, and the fuel function is based on the state at that time. The correction coefficient for FX (in the present embodiment, the initial value and the fuel function correction coefficient KP for the fine adjustment function FXAI) is calculated.

FIG. 2 is a diagram showing an outline of a configuration example of the reference curve correction unit 12 in the present embodiment. The reference curve correction unit 12 further includes, for example, a deviation determination unit 121, a period determination unit 122, an amplitude determination unit 123, a reference curve correction determination unit 124, and a reference curve correction coefficient output implemented by hardware or software as its configuration. It has each part such as part 125. It also has data such as a cycle history 126, an amplitude history 127, an optimum value information 128, and a reference curve correction function VFX, which are implemented as files or tables recorded in a memory or HDD.

The measured main vapor pressure PV and the set main vapor pressure SV input to the reference curve correction unit 12 are input to the deviation determination unit 121, and the difference (deviation) thereof is calculated. The calculated difference is input to the period determination unit 122 and the amplitude determination unit 123, respectively, and the period and amplitude of the fluctuation are calculated as information characterizing the behavior of the measured main vapor pressure PV, respectively. As described above, the behavior of the measured main vapor pressure PV is not constant and changes from moment to moment. Therefore, the period and amplitude shall be calculated as a moving average over a long period of time (eg, 30 minutes). Therefore, the calculated cycle and amplitude information is recorded in a memory, HDD, or the like as a cycle history 126 and an amplitude history 127, respectively.

The calculated period and amplitude values are input to the reference curve correction determination unit 124. The reference curve correction determination unit 124 determines whether or not the period and amplitude values are optimum values (including suitable values in a certain range equivalent thereto). The information related to the optimum value is recorded in a memory, HDD, or the like as the optimum value information 128, for example. Then, when it is determined that the period and the amplitude are in the optimum state, the value of the reference curve correction function VFX set as the variable function is moved until the period and the amplitude deviate from the optimum state.

Based on this reference curve correction function VFX, the reference curve correction coefficient output unit 125 acquires and outputs the reference curve correction coefficient KP corresponding to the load request amount MWD. This reference curve correction coefficient KP corrects the initial value and the fine adjustment function FXAI by multiplying the initial value and the fine adjustment function FXAI.

<Correction processing of initial value and fine adjustment function FXAI>
FIG. 3 is a flow chart showing an example of a processing flow for correcting the initial value and the fine adjustment function FXAI in the present embodiment. Here, the flow of processing up to the portion where the reference curve correction function VFX is set in the reference curve correction determination unit 124 of the reference curve correction unit 12 is shown. After that, the reference curve correction coefficient output unit 125 of the reference curve correction unit 12 acquires and outputs the reference curve correction coefficient KP corresponding to the load request amount MWD based on the set reference curve correction function VFX.

In the reference curve correction unit 12, the deviation determination unit 121 first acquires the set main vapor pressure SV (S01). The set main vapor pressure SV may be set in advance inside the system as a constant as shown in FIG. 1, or may be acquired as an external input from the boiler 2 or the like. After that, the measured main vapor pressure PV transmitted from the main vapor pressure transmitter PX is acquired (S02). The above processing order is an example, and may be executed in the reverse order or in parallel. When the set main vapor pressure SV and the measured main vapor pressure PV are acquired, a deviation process for obtaining the difference between them is performed (S03). The deviation determination unit 121 inputs the calculated difference information to the cycle determination unit 122 and the amplitude determination unit 123, respectively, and returns to step S01 to continue the process.

The cycle determination unit 122 measures the period of fluctuation of the measured main vapor pressure PV with reference to the set main vapor pressure SV based on the information on the difference in the main vapor pressure acquired from the deviation determination unit 121 (S11). For example, based on the history information of the past difference accumulated in a memory (not shown) or the like, the timing at which the sign of the difference is inverted is grasped, and the time interval is set as the cycle. As described above, the behavior of the measured main vapor pressure PV is not constant and changes from moment to moment. Therefore, the cycle is calculated as a moving average based on the history of the past long time (for example, 30 minutes). After that, it is determined whether or not the measured cycle is normal (whether it is an abnormal value such as minus) (S12). If it is not normal (abnormal value) (S12: N), the process returns to step S11 and the cycle measurement process is continued.

Similarly, the amplitude determination unit 123 also measures the amplitude of the fluctuation of the measured main vapor pressure PV with reference to the set main vapor pressure SV based on the information on the difference in the main vapor pressure acquired from the deviation determination unit 121 (. S21). For example, the absolute value of the difference is grasped as the amplitude. The amplitude is also calculated as a moving average of past long-term (for example, 30 minutes) history information. After that, it is determined whether or not the measured amplitude is normal (S22). If it is not normal (S22: N), the process returns to step S21 and the amplitude measurement process is continued.

When both the period and amplitude values are normal (S12: Y, S22: Y), the calculated period and amplitude values are input to the reference curve correction determination unit 124. The reference curve correction determination unit 124 acquires the transition of the period within a certain time range (for example, 5 minutes) in the past (S31), and determines whether or not each period is within a predetermined range (S32). ). If it does not fall within the predetermined range (S32: N), nothing is done, or if the correction process for the reference curve correction function VFX has already been performed, this is terminated (S38). As a result, the reference curve correction coefficient output unit 125 in the subsequent stage acquires and outputs the reference curve correction coefficient KP based on the reference curve correction function VFX at this time.

On the other hand, when the period within a certain time range in the past is within a predetermined range (S32: Y), whether or not the measured period and amplitude are the minimum values so far in the history of past fluctuations, respectively. Is determined (S33). The information of the minimum value so far may be recorded in the optimum value information 128, for example. It should be noted that the period is within the predetermined range in step S32, and it is determined whether or not it is the minimum value. If at least one of the period and the amplitude is not the minimum value (S33: N), nothing is done, or if the correction process for the reference curve correction function VFX has already been performed, this is terminated (S38).

On the other hand, when both the measured period and amplitude are the minimum values (S33: N), the period and amplitude information related to the optimum value so far is acquired from the optimum value information 128 (S34) and compared with this. In (S35), it is determined whether the combination of the measured period and the amplitude is the optimum value. As a method for determining which is the optimum value, an appropriate method can be used, for example, it is assumed that the amplitude value is within a predetermined range and the period is smaller. If the combination of the measured period and amplitude is not the optimum value (S35: N), nothing is done, or if the correction process for the reference curve correction function VFX has already been performed, this is terminated (S38).

On the other hand, if the combination of the measured period and amplitude is the optimum value (S35: Y), the content of the optimum value information 128 is updated by this combination (S36), and the correction process for the reference curve correction function VFX is started. (S37). The reference curve correction function VFX is set as a variable function that defines a curve of the correspondence between the load request amount MWD and the reference curve correction coefficient KP which is a correction coefficient for the initial value and the fine adjustment function FXAI. It is corrected by moving it by a predetermined amount. This correction continues, for example, until the measured period and amplitude deviate from the optimum state. Note that such a correction method is an example, and for example, the reference curve correction function VFX is used by using another index such as the boiler input command value BID in the control state when the combination of the measured period and amplitude is the optimum value. (Or the initial value and the fine adjustment function FXAI) may be corrected.

As described above, according to the boiler combustion control system 1 according to the first embodiment of the present invention, the deviation of the fluctuation of the measured main vapor pressure PV with respect to the main vapor pressure SV is measured as the period and the amplitude, and the length thereof is measured. Determine when the period and amplitude are optimal based on time transitions. Then, the reference curve correction coefficient KP for correcting the fuel function FX (specifically, the initial value and the fine adjustment function FXAI in the present embodiment) is output based on the state when the period and the amplitude are optimal. That is, it is possible to autonomously and self-sufficiently correct a slight deviation occurring in the fuel function FX in real time.

(Embodiment 2)
Next, the second embodiment will be described. In the following, the description of the parts that overlap with the above-described embodiment will be omitted in principle.

In this embodiment, a boiler combustion control system applicable to a supercritical pressure-through boiler and a super-supercritical pressure-through boiler will be described. The amount of fuel input and the amount of water supplied in a supercritical pressure-through boiler and a super-supercritical pressure-through boiler depend on the main vapor pressure and the water-fuel ratio. The water-fuel ratio is a value defined by the weight ratio of the amount of water supplied to the boiler and the fuel. This water-fuel ratio is controlled by a water-fuel ratio master provided outside the boiler combustion control system. The water-fuel ratio master adjusts the fuel input amount while performing integral processing according to the calorific value (main vapor pressure), but in the past, the fuel input amount could not be controlled appropriately and combustion was stabilized. I couldn't.

Therefore, an object of the present embodiment is to provide a boiler combustion control system and the like capable of appropriately controlling the fuel input amount in a supercritical pressure-through boiler and a super-supercritical pressure-through boiler.

FIG. 5 is a diagram showing an outline of a configuration example of a boiler combustion control system according to a second embodiment of the present invention. The configuration other than the boiler combustion control system 201 in the present embodiment has a configuration in which a water supply master 208, a water fuel ratio master 209, and an addition unit 210 are added to FIG.

The water fuel ratio master 209 has a boiler input command value BID, so that the water fuel ratio defined by the weight ratio of water (liquid) supplied to the boiler 2 to the fuel becomes a predetermined value (or within a predetermined range). Adjust BID'(load request amount MWD') and water supply amount. By these controls, the water-fuel ratio master 209 controls the amount of water supplied, the fluid temperature in the pipe, and the surface temperature of the pipe. The water fuel ratio master 209 generates a water fuel ratio master signal based on the measured value of the main steam pressure PV measured by a pressure gauge (not shown) and information such as the amount of water supplied, and outputs the generated water fuel ratio master signal. The water-fuel ratio master signal is a signal related to an increase or decrease in the fuel input amount, and is a positive signal for increasing the fuel input amount in the case of fuel shortage, and a negative signal for decreasing the fuel input amount in the case of excess fuel. ..

The water supply master 208 adjusts the amount of water supplied to the boiler 2 based on the load request amount MWD, the set value of the water fuel ratio, and the like. The addition unit 210 adjusts the boiler input command value BID output from the fuel input amount calculation unit 7 based on the water fuel ratio master signal output from the water fuel ratio master 209.

In this way, the water supply amount and the fuel input amount are adjusted by each part around the boiler 2 based on the set value of the water fuel ratio. However, in the present embodiment, the boiler combustion control system 201 also has the fuel input amount. Control is done. As shown in FIG. 5, the boiler combustion control system 201 has a configuration in which an addition unit 215 is added to the boiler combustion control system 1 of FIG. The addition unit 215 is connected to the water fuel ratio master 209, and based on the water fuel ratio master signal output from the water fuel ratio master 209, the feedback-adjusted boiler input command value BID'(load request amount) output from the addition unit 5 is output. Adjust the value of MWD').

If the water-fuel ratio master signal is a positive signal, the addition unit 215 performs signal processing to add a predetermined value to the boiler input command value BID', and if the water-fuel ratio master signal is a negative signal, the boiler input command value BID. Performs signal processing by subtracting a predetermined value from'. Then, the addition unit 215 outputs the boiler input command value BID'(load request amount MWD') after signal processing to the division unit 11.

The division unit 11 calculates the ratio between the load request amount MWD and the boiler input command value BID'after signal processing, and outputs the ratio to the fuel correction coefficient calculation unit 14. The fuel correction coefficient calculation unit 14 takes the ratio output from the division unit 11 as an input, calculates the fuel correction coefficient K based on the boiler input command value BID'after signal processing, and outputs it by self-learning. The processing in the reference curve correction unit 12 and the multiplication unit 13 is the same as that in the first embodiment.

The fuel correction coefficient K based on the control of the water fuel ratio master 209 is multiplied by the load request amount MWD'(boiler input command value BID') by the multiplication unit 6. Taking this corrected load request amount MWD "(boiler input command value BID") as an input, the fuel input amount calculation unit 7 converts this into a boiler input command value BID by the fuel function FX and outputs it to the addition unit 210. .. The processing in the addition unit 210 is as described above.

According to this embodiment, the following effects can be obtained in addition to the effects in the above-described embodiment. According to the present embodiment, the fuel correction coefficient calculation unit 14 has a load request amount MWD before feedback correction and a load request amount MWD'(boiler input command value BID') after feedback correction adjusted based on the water-fuel ratio. The fuel correction coefficient K is calculated based on the ratio with. According to this configuration, an appropriate fuel correction coefficient K can be calculated based on the control of the water-fuel ratio master 209, so that the fuel input amount can be appropriately controlled even in the supercritical pressure-through boiler and the super-supercritical pressure-through boiler. A boiler combustion control system and the like capable of this are provided.

Further, according to this configuration, since the influence of the water fuel ratio master 209 can be calculated by calculation, the weight of the boiler input command value BID with the control by the water fuel ratio master 209 can be calculated, and stable combustion can be performed. It has become possible.

Although the invention made by the present inventor has been specifically described above based on the embodiments, the present invention is not limited to the above embodiments and can be variously modified without departing from the gist thereof. Needless to say. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to add / delete / replace a part of the configuration of the above-described embodiment with another configuration.

Further, each of the above configurations, functions, processing units, processing means and the like may be realized by hardware by designing a part or all of them by, for example, an integrated circuit. Further, each of the above configurations, functions, and the like may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files that realize each function can be placed in a memory, a hard disk, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

Further, in each of the above figures, the control lines and information lines are shown as necessary for explanation, and not all the control lines and information lines in the implementation are necessarily shown. In practice, it can be considered that almost all configurations are interconnected.

The present invention can be used in a boiler combustion control system for determining a fuel input amount to a boiler based on a load requirement of the boiler, and a boiler combustion control method.

1,201 ... Boiler combustion control system, 2 ... Boiler, 3 ... Steam turbine, 4 ... PID control unit, 5 ... Addition unit, 6 ... Multiplication unit, 7 ... Fuel input amount calculation unit,
11 ... Division unit, 12 ... Reference curve correction unit, 13 ... Multiplication unit, 14 ... Fuel correction coefficient calculation unit,
121 ... Deviation determination unit, 122 ... Period determination unit, 123 ... Amplitude determination unit, 124 ... Reference curve correction determination unit, 125 ... Reference curve correction coefficient output unit, 126 ... Period history, 127 ... Amplitude history, 128 ... Optimal value information ,
215 ... Addition part,
SV ... Set main vapor pressure, PV ... Measured main vapor pressure, PX ... Main vapor pressure transmitter, MWD, MWD', MWD "... Load requirement, BID, BID', BID" ... Boiler input command value, K ... Fuel Correction coefficient, KP ... Reference curve correction coefficient, FX ... Fuel function, FXAI ... Initial value and fine adjustment function, VFX ... Reference curve correction function

Claims (7)

Fuel related to the fuel input amount to the boiler calculated based on a predetermined fuel function with respect to the load required amount is supplied to the boiler, and the measured main steam pressure which is the main steam pressure of the boiler measured and the measured main steam pressure in advance. The feedback correction amount is obtained based on the set main steam pressure which is the main steam pressure of the boiler, and the load requirement amount or the fuel input amount is corrected based on the feedback correction amount. A boiler combustion control system that outputs a fuel correction coefficient that corrects the load requirement amount or the fuel input amount after feedback correction.
The fuel correction coefficient is based on the ratio of the load required amount before and after the feedback correction, and the initial value and the fine adjustment function that define the initial value of the relationship between the load required amount and the fuel input amount for the boiler. Fuel correction coefficient calculation unit to calculate
It has a reference curve correction unit that outputs a reference curve correction coefficient that corrects the initial value and the fine adjustment function.
The reference curve correction unit
A deviation determination unit that calculates the deviation between the measured main vapor pressure and the set main vapor pressure,
A cycle determination unit that acquires and records the cycle related to the fluctuation of the deviation, and
An amplitude determination unit that acquires and records the amplitude related to the fluctuation of the deviation, and
A reference curve correction coefficient output unit that calculates and outputs the reference curve correction coefficient based on a predetermined reference curve correction function, and a reference curve correction coefficient output unit.
A reference curve correction determination unit that determines whether or not the combination of the period and the amplitude satisfies a predetermined condition, and corrects the reference curve correction function based on the control state for the boiler when the condition is satisfied. And, with, boiler combustion control system. In the boiler combustion control system according to claim 1,
The condition is that the amplitude is within a predetermined range and the period is the smallest in the history of a fixed time range in the past. In the boiler combustion control system according to claim 1,
A boiler combustion control system in which the period determination unit and the amplitude determination unit acquire the period and the amplitude by a moving average in a certain time in the past, respectively. In the boiler combustion control system according to claim 1,
The reference curve correction function is set as a variable function,
The reference curve correction determination unit is a boiler combustion control system that corrects the reference curve correction function by moving the reference curve correction function while the combination of the period and the amplitude satisfies the above condition. In the boiler fuel control system according to claim 1,
The fuel correction coefficient calculation unit is the load after the feedback correction adjusted based on the water fuel ratio defined by the weight ratio of the water supplied to the boiler and the fuel to the load request amount before the feedback correction. A boiler fuel control system that calculates the fuel correction coefficient based on the ratio with the required amount. Fuel related to the fuel input amount to the boiler calculated based on a predetermined fuel function with respect to the load required amount is supplied to the boiler, and the measured main steam pressure which is the main steam pressure of the boiler measured and the measured main steam pressure in advance. The feedback correction amount is obtained based on the set main steam pressure which is the main steam pressure of the boiler, and the load requirement amount or the fuel input amount is corrected based on the feedback correction amount. A boiler combustion control method in a boiler combustion control system that outputs a fuel correction coefficient that corrects the load requirement amount or the fuel input amount after feedback correction.
The fuel correction coefficient is based on the ratio of the load required amount before and after the feedback correction, and the initial value and the fine adjustment function that define the initial value of the relationship between the load required amount and the fuel input amount for the boiler. Fuel correction coefficient calculation process to calculate
It has a reference curve correction step that outputs a reference curve correction coefficient that corrects the initial value and the fine adjustment function.
The reference curve correction step is
A deviation determination step for calculating the deviation between the measured main vapor pressure and the set main vapor pressure,
A cycle determination step of acquiring and recording a cycle related to the fluctuation of the deviation, and
An amplitude determination step of acquiring and recording the amplitude related to the fluctuation of the deviation, and
A reference curve correction coefficient output step of calculating and outputting the reference curve correction coefficient based on a predetermined reference curve correction function, and a reference curve correction coefficient output process.
A reference curve correction determination step of determining whether or not the combination of the period and the amplitude satisfies a predetermined condition, and correcting the reference curve correction function based on the control state for the boiler when the condition is satisfied. And, the boiler combustion control method. In the boiler combustion control method according to claim 6,
Prior to the fuel correction coefficient calculation step, the load requirement amount after the feedback correction is adjusted based on the water-fuel ratio defined by the weight ratio of water supplied to the boiler and the fuel, and before the feedback correction. It has a step of calculating the ratio between the load demand amount and the load demand amount after the feedback correction after adjustment.
In the fuel correction coefficient calculation step, a boiler combustion control method for calculating the fuel correction coefficient based on the ratio calculated based on the load requirement amount after the feedback correction after adjustment.

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