JPH08338602A - Boiler controller - Google Patents

Abstract

PURPOSE: To reduce variations of boiler outlet steam-temperature and steam pressure by estimating an actually measurable physical quantity based upon previously supposed parameters (fuel ratio, crushing property figure, etc.), and when the physical quantity is not coincident with a corresponding actually measured value, correcting the parameters in succession. CONSTITUTION: A boiler heat transfer dynamic characteristic model 40 obtains a fire furnace outlet gas temperature calculated value 51 by analysis of combustion and radiation in a fire furnace based upon fine powdered coal amount estimation signals 45, 46 of each burner at that time and a signal 48 yielded by synthesizing a presupposed fuel ratio increase and a fire furnace contamination increase. A fuel ratio estimation value 43 judges the previously supposed signal 48 to be overestimated and reduces it provided a calculated value 49 of combustion waste gas temperature at an superheater outlet based upon an optimum coefficient (Karman gain) estimated by an expanded Karman filter technique is larger than a calculated value. The fuel ratio estimator 43 increases the signal 48 provided a relation between the calculated value 49 and the actually measured value signal 47 is opposite to the above described case, and finally converges the signal 48 to a true value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a pulverized coal burning boiler, and particularly for pulverizing a wide variety of coals, and
The present invention relates to a control device suitable for always ensuring good control responsiveness with respect to steam temperature and pressure of the boiler even when the equipment changes over time.

[0002]

2. Description of the Related Art FIG. 4 shows a pulverized coal production facility, a boiler device for combusting the pulverized coal calculated by the facility, and a control device according to the prior art.

The coal feeder 2 for supplying the raw coal 1 adjusts the raw coal feeding speed according to the speed signal 3 and supplies the raw coal in proportion to the signal 3 to the hopper 4 of the pulverized coal manufacturing facility.

The raw coal 1 is rotated by an electric motor 5, drops on a turntable forming a mixing means 6, and is mixed with a collecting coal 11, 13 by a classifying means which will be described later to form a retained coal 7.

The retained coal 7 is crushed by a roller placed on the outer circumference of the above-mentioned turntable which constitutes the crushing means 8 by centrifugal force, and is carried by carrier air 9 blowing up the outer circumference to be transported to a customer. At this time, a fluidized bed 10 made of pulverized coal is formed outside the crushing means 8.

[0006] Next, the pulverized coal carried on the carrier air 9 has a large particle size due to the balance with gravity.
A flow of the gravity-classified collecting coal 11 is recirculated to the flow.
Further, the pulverized coal having a relatively small particle size and having passed through the gravitational classification is swirled by the vanes 12 and a flow of centrifugally classified collecting coal 13 in which particles having a large particle size are similarly recirculated by centrifugal force is generated. .

Coal having a small particle size, which has passed through such a two-stage classification means, is sent to the boiler device through the pulverized coal transport pipe 14 and forms a flame 15 by combustion.

In the boiler device, steam boiler water supply 16
Is supplied to the steam can 17 from the water supply pump 37, and the downcomer pipe 1
After passing through the riser 20 and being stored in the upper part of the steam can 17, the superheater 29 is superheated through the superheater connecting pipe 21. The steam exiting the superheater 29 is supplied to the demand destination from the steam supply line. At this time, the signal from the steam temperature detector 31 and the steam temperature target value signal (setting signal) 33 from the steam temperature signal setting unit 32 are supplied. The opening degree of the water injection valve 36 is adjusted using the proportional / integral element (PID adjuster) 35 based on the deviation from and, and the steam temperature control is performed by the water injection in the steam desuperheater 30.

On the other hand, most of the steam flow rate of the steam supply line except for the small amount of water injection by the water injection valve 36 is the water wall 1 of the furnace.
Since the steam pressure is supplied by evaporation, the steam pressure can be controlled by adjusting the fuel supply amount by the pulverized coal tube 14 that controls the heat absorption amount of the furnace water wall 19.

Therefore, the deviation signal 26 between the signal from the steam pressure detector 22 and the steam pressure setting signal 24 is converted into the PID controller 27.
To obtain a coal feeder speed signal 3. Reference numeral 23 is a signal setting device, 26 is a steam pressure deviation signal, and 28 is a furnace outlet combustion gas.

The boiler apparatus of FIG. 4 operates in principle on the assumption that an arbitrary amount of steam is extracted from a steam demand destination, and the element 3
5. The control loop having the element 27 as a core controls the steam pressure and the temperature to be kept constant regardless of the steam amount.

[0012]

The boiler and the boiler control device shown in FIG. 4 operate well if the boiler and the coal crusher have little dirt and wear and the property of coal is almost constant.
However, if the conditions favorable to the operation of these boilers collapse, the problems described below will occur.

Although there are various factors in the properties of coal, the grindability index and the fuel ratio are important in the following discussion. The former is easily crushed if the value is large, and the latter is the ratio of fixed carbon to volatile matter of coal, and if the value is large, it takes time to burn. It is known that these values differ greatly depending on the type of coal, and that there is considerable variation even for the same type of coal.

FIG. 5 shows the "mill response time constant" and the "heat absorption amount of the furnace water wall" which can be said to control the control characteristics of the boiler. The relationship is shown.

Here, the "mill response time constant" is that the change in the amount of pulverized coal supplied to the burner by the crusher with respect to the change in the amount of coal supplied to the crusher is a first-order lag characteristic. Focusing attention, it is defined as the magnitude of the delay. The time constant increases as the crushability index decreases and the wear of the crushing mechanism progresses.

Further, even if the fuel is burned at the same fuel flow rate, the fuel ratio and the fouling of the furnace increase and the "heat absorption amount of the water wall of the furnace" increases.
Decreases and the heat absorption of the superheater on the downstream side of the combustion gas increases.

At this time, the "furnace outlet gas temperature" increases,
In the steady state with the same amount of fuel, the “furnace outlet gas temperature” and the “furnace water wall heat absorption amount” can be uniquely obtained by knowing one of them, so the “furnace water wall heat absorption amount” characteristic is often understood. Treated as an easy "furnace exit gas temperature" characteristic of.

Based on the above, the boiler and the boiler control device of FIG. 4 have the following problems.

A) The heat absorption distribution of the furnace water wall 19 and the superheater 29 changes due to the change of the fuel ratio and the progress of the fouling of the furnace. Regarding the change in the heat absorption balance, for example, when the furnace water wall 19 decreases and the superheater 29 increases due to an increase in the fuel ratio, the water injection valve 36 is provided to prevent the steam temperature from rising and to supplement the insufficient evaporation amount on the water wall. It is necessary to increase the opening. Since the balance correction is constantly required including the reverse case, it is likely that the water injection valve 36 is always operated near the fully opened or fully closed position. In the vicinity of the fully opened and fully closed, the water injection valve 36
There is a small room for control on one side of the opening, and it may not be possible to cope with the transient fluctuation of the steam temperature.

B) The response time constant of the coal crusher, the burning rate of the fuel in the furnace, and the heat transfer to the water wall due to the progress of the crushability index of coal, the change in the fuel ratio, the wear of the crushing mechanism, and the progress of dirt in the furnace. The delay changes, and the response characteristics of the steam pressure detector 22 with respect to the amount of coal fed at the inlet of the coal pulverizer differ greatly. Therefore, PI
In order to prevent hunting under any circumstance, the D element 27 is based on the case of the slowest feed rate-steam pressure response,
It is necessary to set low sensitivity and long integration time, which is far from achieving good control performance.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a boiler control device capable of reducing fluctuations in steam temperature and steam pressure at a boiler outlet.

[0022]

The above problem a) can be solved by the following items 1) and 2), and b) by items 3) and 4), respectively. In short, the points of the present invention are the following 2) and 3), and the estimation of the state quantities such as the furnace outlet gas temperature, the burner inlet pulverized coal flow rate, etc., and the coal fuel ratio are made by the dynamic characteristic model of online operation. Detects operating characteristic fluctuation factors (parameters) such as pulverization index, furnace dirt, abrasion of pulverized coal pulverization part, etc.

In particular, the latter detection is a search for model parameters, in which a measurable physical quantity is calculated based on preliminarily assumed parameters (fuel ratio, pulverizability index, etc.), and the value matches the corresponding measured value. If not, the parameters are sequentially corrected, and the correction is repeated until the two match.

1) The measured values of the steam temperature and pressure at the boiler outlet are compared with the target values, and when the steam temperature is high or the steam pressure is low, the target value of the furnace outlet gas temperature is lowered, and conversely the temperature is low. Alternatively, when the pressure is high, the target value of the furnace outlet gas temperature is increased.

2) An on-line boiler heat transfer dynamic characteristic model for sequentially inputting the fuel supply amount to each burner at that time is provided, and the combustion gas temperature downstream from the superheater is measured and calculated by the model. Focusing on the deviation of the values, the fuel ratio of the coal at that time, the contamination of the furnace are detected, and when both increase, with respect to the furnace outlet gas temperature, with respect to the target value given by the method of 1) When the value calculated by the model exceeds, the fuel to be supplied to the boiler at that time is distributed to the burner located far from the exhaust gas outlet in the furnace. On the contrary, when the fuel ratio and the fouling of the furnace are reduced, and when the calculated value of the furnace outlet gas temperature is lower than the target value, a large amount of fuel is distributed to the burner located near the exhaust gas outlet.

3) A dynamic characteristic model of an on-line coal crusher that sequentially inputs operating conditions such as the amount of coking coal supplied at that time and the pressing force of the crusher is provided, and the model is conveyed in the vicinity of the coal crusher of the crusher. Regarding the differential pressure generated by the working air, paying attention to the deviation between the measured value and the calculated value by the model,
The crushability index of the coal at that time and the wear of the crushing mechanism are detected, and when the former decreases or the latter increases, the pressing force of the crushing mechanism of the crusher is increased. In the opposite case, the applied pressure is reduced.

Further, when the amount of pulverized coal supplied to the burner by the pulverizer falls below the target value given by the means in the item 2), the raw coal for the pulverizer is supplied. Increase the supply, and vice versa.

4) The fuel ratio according to the item 2), the detected value of the fouling of the furnace, the grindability index according to the item 3), and the detected value of the wear of the crushing mechanism are combined to obtain the above-mentioned coal supply amount-steam pressure response. The delay time constant is evaluated, and if the value increases, the sensitivity of the PID element is reduced and the integration time is extended. When the value decreases,
The reverse adjustment is made to the PID element. The adjustment is carried out when the delay time constant of the coal supply amount-steam pressure response changes from a predetermined value even after the fuel distribution to each burner according to the item a) and the correction of the pressing force according to this item are performed. To do.

[0029]

The operation of the above means 1) to 4) will be described in detail below. The core of these actions are 2) and 3), and the necessary operation is performed based on the estimation of the plant state quantity that cannot be grasped by the direct online measuring means and the detection of the operating characteristic variation factors using the plant model as described above. I do.

1) When the boiler outlet steam temperature is high or the steam pressure is low, the target value of the furnace outlet gas temperature is lowered,
Through the action of item 2), the heat absorption amount is reduced by the superheater and increased by the water wall of the furnace. In the opposite case, the superheater has the effect of increasing the water wall of the furnace.

2) When the fuel ratio and the fouling of the furnace increase,
And, when the calculated value of the furnace outlet gas temperature rises above the target value, a large amount of fuel is distributed to the burner located far from the exhaust gas outlet to extend the passage time of the combustion exhaust gas in the furnace and secure the combustion time. It has the effects of increasing the heat absorption of the furnace, lowering the temperature of the gas at the furnace outlet, and lowering the heat absorption of the superheater. In the case where the fuel ratio is decreased or the like is the reverse of the above, the same effect is exerted in the opposite direction below the decrease in the furnace heat absorption amount.

3) When the crushability index of coal is reduced or the wear of the crushing mechanism progresses, the pressing force of the crushing mechanism is increased to enhance the crushing ability. In the opposite case, the pressing force is reduced to suppress the progress of wear of the crushing mechanism and reduce vibration. If there is an excess or deficiency in the amount of pulverized coal supplied to the burner that the crusher is responsible for, the amount of coal supplied to the crusher is immediately adjusted to correct it.

4) When the delay time constant of the coal supply amount-steam pressure response is short, the sensitivity of the PID element is increased, the integration time is shortened, and the controllability is further improved. In the opposite case, P
The ID element is carefully controlled to prevent hunting.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a system diagram of the entire boiler apparatus according to the embodiment. Descriptions of components common to the conventional example shown in FIG. 4 are omitted.

The means 1) to 4) described in the section of means for solving the problems are correspondingly implemented as follows.

1) The furnace outlet combustion gas temperature setting device 55 is
By implementing the method 1), the steam temperature deviation signal 34 and the steam pressure deviation signal 26 are multiplied by "weighting coefficient" for each of the separately determined signals and added to correct the value of the furnace outlet gas temperature basic signal. To be realized. The optimum value of the “weighting coefficient” is obtained by applying a known optimum regulator method to the plant heat transfer model.

If the "weighting coefficient" is obtained by this method, optimum control characteristics can be realized under the known LQG standard.
Further, in order to achieve this function, a PI controller or a fuzzy calculator can be applied.

2) The furnace outlet gas temperature control device 38 implements the means 2), and details thereof are shown in FIG.

The boiler heat transfer kinetic characteristic model 40 is based on the pulverized coal amount estimation signals 45 and 46 of each burner at that time point and the signal 48 obtained by combining the presumed fuel ratio increase and the furnace fouling progress, based on an empirical formula and the like. A furnace outlet gas temperature calculated value 51 is obtained by analysis of combustion and radiation in the furnace used together.

Furthermore, from the exhaust gas amount obtained from the furnace outlet gas temperature and the amount of pulverized coal of each burner, the enthalpy of the exhaust gas, the superheater outlet steam temperature signal 74, and the heat absorption amount on the superheater steam side obtained from the steam pressure signal 75, By calculating the heat balance, a calculated value 49 of the exhaust gas temperature at the outlet of the superheater is obtained.

The fuel ratio estimator 43 calculates the combustion exhaust gas temperature at the outlet of the superheater by using the optimum coefficient (Kalman gain) obtained by the known extended Kalman filter method.
If 9 is larger than the measured value signal 47, it is concluded that the previously assumed signal 48 is overestimated, and this is reduced.

The fuel ratio estimator 43 increases the signal 48 when the calculated value 49 has the relationship of the measured value signal 47 opposite to the above,
Finally, the signal 48 is converged to a true value. The convergence is logically guaranteed by using the optimum coefficient obtained by the Kalman filter method.

The optimum pulverized coal amount calculator 44 at each burner inlet is
The total fuel amount signal 53 obtained by the PID element 27 is converted into the signal 48
And proportional distribution based on the control deviation 54 of the furnace outlet gas temperature, and the pulverized coal supply amount target signals 56 and 57 of each burner are calculated. In this case, the distribution coefficient is the signal 48, the signal 54.
Is multiplied by a “weighting coefficient” and added.

The optimum value of the "weighting coefficient" is obtained by applying a known optimum regulator method to the combustion in the furnace and the radiant heat transfer model. If the "weighting coefficient" is obtained by the method, the optimum control characteristic can be realized under the known LQG standard.

Further, the fuel ratio estimator 43 and the burner inlet optimum pulverized coal amount calculator 44 may each be a fuzzy calculator or a PI controller.

Further, in the present embodiment, the calculated value 69 obtained by the pulverizer coal output control device described later is applied as the pulverized coal amount estimation signals 45 and 46 of each burner, but the values can be measured. In this case, this can be used, or as in the case of storing pulverized coal in the bin system and supplying it to each burner via a valve, the pulverized coal of each burner can be ignored with a delay that can be ignored by the commands of signals 56 and 57. When the amount of charcoal follows, it is easy to use signals 56 and 57 instead of signals 45 and 46.

3) The pulverizer coal output control device 39 executes the means 3), and details thereof are shown in FIG.

The crusher dynamic characteristic model 58 receives the amount of coal supplied to the crusher at that time as a signal 65 and the crushing mechanism pressing force as a signal 64, and reduces the crushability index and the wear of the crushing mechanism which are assumed in advance. Based on the signal 66 that is a composite of the progression,
Pulverized coal supplied to the differential pressure calculation value 67 in the vicinity of the crushing mechanism and a single burner or a plurality of burners belonging to a specific group, which is in charge of the crusher, by analyzing phenomena such as crushing, classification, and mixing in the crusher The calculated quantity 69 is obtained.

The grindability index estimator 60 uses the optimum coefficient (Kalman gain) obtained by the method of the known extended Kalman filter to calculate the calculated value 67 when the load is increased from the difference between the calculated differential pressure value 67 and the measured value 63. If the calculated value 67 is larger than the value signal 63 or the calculated value 67 is smaller than the measured value signal 63 when the load is decreased, the phase of the calculated value is ahead of the measured value, and the previously assumed signal 66 is overestimated. Conclude and reduce this.

The fuel ratio estimator 43 increases the signal 66 when the calculated value 67 has the relationship of the measured value signal 63 opposite to the above,
Finally, the signal 66 is converged to a true value. The convergence is theoretically guaranteed by using the optimum coefficient obtained by the Kalman filter method.

The pulverizer optimum pulverized coal amount calculator 62 supplies the pulverized coal supplied to the singular or a plurality of burners belonging to a specific group instructed by the pulverized coal supply amount target signals 56 and 57 of each burner. Based on the deviation between the coal amount 70 and the calculated value 69, and the signal 66 obtained by the fuel ratio estimator 43, these are multiplied by a "weighting coefficient" and added, and the coal supply amount command signal 72 to the crusher is added. The pressure command signal 73 is calculated.

The optimum value of the "weighting coefficient" is obtained by applying a known optimum regulator method to the model of the crusher.

By obtaining the "weighting coefficient" by this method, the optimum control characteristic can be realized under the known LQG standard.
Further, a fuzzy calculator or a PI controller can be applied to the crushability index estimator 60 and the crusher optimum pulverized coal amount calculator 62, respectively.

Further, in this embodiment, as the coal supply amount signal 65 and the pressing force signal 64 to the crusher, the follow-up delay of these drive systems (coal feeder and pressurizer of the crushing mechanism) is commanded. On the other hand, the respective command value signals 72 and 73 are simply used as they are, assuming that they are negligible. However, if the value can be measured, it is more accurate if used.

4) The PI parameter controller 81 carries out the procedure 4) of the means, and detects the fuel ratio by the signal 48, the detected value of the dirt of the furnace, the crushability index by the signal 66, and the detected value of the wear of the crushing mechanism. Overall, the delay time constant of the coal supply amount-steam pressure response is evaluated, and if the value increases, the sensitivity of the PID element 35 is reduced and the integration time is extended. When the value decreases, the PID element 35 is adjusted in the opposite way. The adjustment is theoretically guaranteed to be optimal by using the known Ziegler-Nicholas method, and fuzzy inference can be used.

In the present embodiment, the signal 66 for a specific crusher is represented by the signal 66 for all crushers for the sake of simplicity as the crushability index and the detected value of wear of the crushing mechanism. The average value is accurate.

37 is a water supply pump, 41 and 42 are signal subtractors, 50 is a heat transfer surface outlet gas temperature calculation deviation signal, and 5 is a signal.
2 is a furnace outlet combustion gas temperature command signal, 59 and 61 are signal subtractors, 71 is a burner inlet pulverized coal amount control deviation signal, 76
Is a furnace outlet combustion gas basic setting signal, 77 is a signal setting device,
Reference numeral 78 is a heat transfer surface outlet gas temperature setting device, 79 is a pressurizing force controller, 80 is a mill differential pressure controller, and 82 is a PI parameter correction signal.

[0059]

The present invention has the following effects.

1) It is possible to reduce fluctuations in the boiler outlet steam temperature and the steam pressure due to the transient imbalance of the heat absorption amount between the superheater and the water wall of the furnace, which occurs when the amount of steam extracted from the boiler changes.

2) It is possible to prevent the situation where the heat absorption distribution of the furnace water wall and the superheater changes due to the change of the fuel ratio and the progress of the fouling of the furnace, and the operation of the water injection valve is normally opened or fully closed. . Therefore, it is possible to prevent a decrease in control room due to the steam temperature fluctuation.

3) When the crushability index of coal or the wear of the crushing mechanism is changed, by appropriately securing the crushing ability,
It is possible to both suppress the progress of wear, reduce vibration, and improve fluctuations in boiler outlet steam temperature and steam pressure by improving crusher coal output responsiveness.

4) When the controllability of coal is good even when the controllability of the plant is deteriorated even when the controllability of the coal is changed, the abrasion of the fuel ratio is changed, the abrasion of the crushing mechanism is changed, and the degree of fouling of the furnace is changed. Can maximize the driving characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control device according to a second embodiment of the present invention.

FIG. 3 is a system diagram of the entire boiler apparatus according to the embodiment of the present invention.

FIG. 4 is a system diagram of an entire boiler device according to a conventional example.

FIG. 5 is an explanatory diagram of driving characteristic variation factors.

[Explanation of symbols]

 38 Furnace outlet gas temperature control device 39 Crusher coal output control device 40 Heat transfer dynamic characteristic model 41, 42 Signal subtractor 43 Fuel ratio estimator 44 Pulverized coal flow rate calculator 58 Crusher dynamic characteristic model 59, 61 Signal subtractor 60 Crushability estimator 62 Crusher optimum operation amount calculator

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Takase Kawase 6-9 Takaracho, Kure-shi, Hiroshima Prefecture Babkotsu Hitachi Co., Ltd. Kure Factory (72) Katsumi Shimohira 3-36 Takaracho, Kure-shi, Hiroshima Prefecture Babkotsu Hitachi Stock Company Kure Institute

Claims (5)

[Claims] 1. A boiler apparatus having a furnace, a water-cooling wall surrounding the furnace, and a superheater for superheating steam generated on the water-cooling wall in an exhaust gas passage of the furnace, wherein at least steam pressure and outlet of the superheater are provided. A boiler control device comprising: a calculation unit for inputting a measured value or an estimated value of a steam temperature and instructing a target value of an exhaust gas temperature at the exit of the furnace. 2. A furnace equipped with a pulverized coal burner having means for adjusting the pulverized coal flow rate individually or in groups at a plurality of positions at different distances from the exhaust gas outlet, a water cooling wall surrounding the furnace, and exhaust gas from the furnace. In a boiler device having a superheater that superheats the steam generated on the water cooling wall in the flow path, at least the steam pressure, the steam temperature at the superheater outlet, the pulverized coal flow rate of each burner, and the fuel ratio of the pulverized coal Heat transfer kinematics that inputs the measured value or estimated value and calculates the exhaust gas temperature at the outlet of the furnace at that point in time, and the exhaust gas temperature in a specific part in the exhaust gas flow passage that is downstream of the superheater A model, and at least a fuel ratio estimator that estimates the fuel ratio of the pulverized coal currently used for combustion from the deviation between the measured value and the measured value of the heat transfer dynamics model for the exhaust gas temperature of the specific part. Also, with respect to the exhaust gas temperature at the outlet of the furnace, the deviation between the calculated value by the heat transfer dynamic characteristic model and the target value, the fuel flow rate command value to be supplied to the boiler at that time, and the estimated fuel ratio value are input. A boiler control device comprising: a fuel distribution calculator that outputs a target value of a fuel flow distribution of a pulverized coal burner. 3. A coal crusher for supplying pulverized coal to a burner of a boiler apparatus, wherein the crusher comprises at least a coal holding part, a grinder groove adjacent to the holding part, and a carrier air for crushed coal. Supply means, means for detecting the pressure difference between the specific parts of the upstream and downstream parts of the crushing mechanism along the conveying air flow path, means for operating the amount of coal supplied to the crusher, and addition of the crushing mechanism. It has a pressure operating means, and at least inputs the current coal supply amount to the crusher, the pressing force of the crushing mechanism, and the measured or estimated value of the crushability index of the supplied coal, and The pulverized coal flow rate supplied to the burner by the crusher, the dynamic characteristic model of the crusher for calculating the differential pressure between the specific parts, and at least the calculated value by the pulverizer dynamic characteristic model and the differential pressure detection means for the differential pressure. Due to the deviation from the measured value, A grindability estimator for estimating the grindability index of charcoal, and at least a deviation between the calculated value by the grinder dynamic characteristic model and the target value for the pulverized coal flow rate supplied to the burner by the grinder, and the grindability by the grindability estimator. A boiler control device comprising: a crusher operation amount calculator for inputting an index and instructing the amount of coal supplied to the crusher and the pressing force of the crushing mechanism. 4. The method according to claim 2, wherein the command value of the total amount of fuel supplied to each burner of the boiler device is calculated according to the deviation from the target value of the temperature or pressure of a specific part of the boiler, and the deviation is calculated. The boiler control device further comprising a calculation unit including a coefficient adjusting means for multiplying, and adjusting a coefficient by which the deviation is multiplied based on an estimated value of the fuel ratio estimator. 5. The method according to claim 3, wherein the command value of the total amount of fuel supplied to each burner of the boiler device is calculated according to the deviation from the target value of the temperature or pressure of a specific part of the boiler, and the deviation is calculated. A boiler control apparatus further comprising a calculation unit including a coefficient adjusting means for multiplying, and adjusting a coefficient by which the deviation is multiplied based on an estimated value of the pulverizability estimator.