JP2018103067A - Processing unit, method and program in pulverization plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both that mill inlet temperature does not exceed an upper limit value as much as possible and the feed amount of a raw material is increased as much as possible.SOLUTION: In a processing method in a pulverization plant: multiplying PID control gain by the standard deviation of the measured value of mill outlet temperature for a given time and the estimate value of the standard deviation of mill inlet temperature is derived; the set value of the mill inlet temperature is derived on the basis of the upper limit value of the mill inlet temperature and the estimate value of the standard deviation of the mill inlet temperature; a maximum coal feed amount is derived on the basis of the set value of the mill inlet temperature, outside air temperature and coal moisture; and the set value of a coal feed amount is changed so that the coal feed amount approaches the maximum coal feed amount when a state that the coal feed amount exceeds or is less than the maximum coal feed amount continues for a given time.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a processing apparatus, method, and program in a grinding plant, and is particularly suitable for use in a grinding plant.

As an example of a pulverization plant for producing pulverized coal, cement or the like, there is a PCI plant that pulverizes coal to perform pulverized coal injection (PCI; Pulverized Coal Injection).
In the PCI plant, first, fuel gas (combustion gas) and combustion air are supplied to a hot gas generator, and hot air is generated as exhaust gas in the hot gas generator. The exhaust gas is supplied to the inside of a pulverizer that pulverizes the raw material. The raw material (powder) pulverized by the pulverizer is supplied to the bag filter (filter cloth (fiber cloth or nonwoven fabric)) together with the exhaust gas, and is collected by the bag filter.
In a negative pressure / exhaust gas circulation system PCI plant, hot air (exhaust gas) is pressurized by a circulation fan and supplied to the hot gas generator again as a circulation gas. On the other hand, in a one-pass PCI plant, hot air (exhaust gas) is not circulated but is directly diffused into the atmosphere from the chimney.

  In any PCI plant, the mill inlet temperature, which is the temperature of gas in the piping on the inlet side of the pulverizer, and the mill outlet temperature, which is the temperature of pulverized coal in the piping on the outlet side of the pulverizer, are operated. Done. If the mill inlet temperature becomes too high, the expansion and contraction pipes connecting the pipes may burn, or the raw material (coal) supplied to the pulverizer may ignite. Therefore, an upper limit is set for the mill inlet temperature.

  On the other hand, in order to keep the moisture contained in the pulverized coal produced by pulverizing the raw material (coal), it is desirable to keep the mill outlet temperature constant. Therefore, as described in Patent Document 1, mill outlet temperature control for keeping the mill outlet temperature constant is performed. Mill outlet temperature control is control which operates the load of the burner which comprises a hot gas generator in order to make a mill outlet temperature track target temperature. In Patent Document 1, when heat-up is completed and coal supply is started, a burner load having a constant flow rate according to the operating conditions is applied to the hot gas generator until the mill outlet temperature decreases to the target value, and the mill outlet After the temperature drops to the target value, the mill outlet temperature control is performed.

  As described above, there is an upper limit for the mill inlet temperature, and the hot gas generator is operated so that the mill outlet temperature is constant. Therefore, when the mill inlet temperature becomes high, the coal supply amount is lowered. It will be. Lowering the amount of coal supplied will reduce the production of pulverized coal. Therefore, the amount of coal supply is controlled automatically or manually within a range where the mill inlet temperature does not exceed the upper limit. Even if the amount of coal supply is controlled so that the mill inlet temperature is constant, disturbances always enter the PCI plant due to the fact that the amount of coal supply does not exactly follow the set value. As a result, the mill inlet temperature varies. Since the purpose of controlling the mill inlet temperature is to prevent the mill inlet temperature from exceeding the upper limit value, generally, a method is adopted in which the target value of the mill inlet temperature is set to a value that allows for such variation. . At this time, if the variation in the mill inlet temperature is estimated too small, the target value of the mill inlet temperature becomes higher than necessary, and the risk that the mill inlet temperature exceeds the upper limit increases. On the other hand, if the variation is estimated too much, the target value of the mill inlet temperature becomes lower than necessary, and the production amount of pulverized coal cannot be sufficiently increased.

Therefore, a method is conceivable in which variations in the mill inlet temperature are predicted and a target value for the mill inlet temperature is set in accordance with the variations. As a method for setting a target value in a plant, there are techniques described in Patent Documents 2 and 3.
In Patent Document 2, a simulation control system (model) that simulates a plant control system is provided, a reference target value is supplied to the simulation control system based on a reference trajectory, a prediction response is obtained, and the obtained prediction response is evaluated. It is disclosed that an optimum target trajectory is obtained by correcting a reference trajectory based on a result, and an optimum target value is determined based on the obtained optimum target trajectory.

  In Patent Document 3, the amount of variation in the measurement signal is obtained for each operation state of the plant, and a control target value that increases the operation efficiency of the plant based on the obtained amount of variation in the measurement signal and the constraint value in the operation of the plant. It is disclosed to seek.

JP 2014-114994 A JP 2002-207503 A JP 2013-206363 A

  However, the technique described in Patent Document 2 uses a simulated control system (model) that simulates a plant control system. As described above, variations in the mill inlet temperature are caused by disturbance. Therefore, even if the technique disclosed in Patent Document 2 is used, it is not easy to accurately represent the disturbance in the mill inlet temperature because it is not easy to represent the disturbance as a model.

Moreover, in the technique described in Patent Document 3, it is assumed that the measurement signal for each operating state fluctuates with a steady value as a reference. The steady value of the mill inlet temperature has a strong correlation with the coal supply amount, raw material moisture, and outside temperature, but these change from moment to moment. Therefore, even if the technique described in Patent Document 2 is used, it is not easy to accurately determine the steady value, and thus it is not easy to accurately predict the variation in the mill inlet temperature.
As described above, in the conventional technology, it is not easy to accurately predict the variation in the mill inlet temperature, so that the mill inlet temperature should not exceed the upper limit as much as possible, and the supply amount of the raw material should be reduced. It was not easy to achieve as many as possible.

  The present invention has been made in view of the above problems, and prevents the mill inlet temperature from exceeding the upper limit as much as possible and increases the supply amount of raw materials as much as possible. It aims at making both compatible.

  The processing apparatus in the pulverization plant of the present invention includes a hot air generator that generates hot air as exhaust gas, a pulverizer that pulverizes the raw material, and discharges the pulverized raw material to the outside on the flow of the exhaust gas, and the pulverizer A raw material supply device for supplying the raw material to the pulverizer, and a collector for collecting the pulverized raw material released from the pulverizer along the flow of the exhaust gas. A processing apparatus in a pulverization plant that performs processing on a pulverization plant that is controlled to operate the hot air generator in accordance with a deviation between a measured value of a mill outlet temperature that is a temperature at a position and a target value. Mill outlet temperature variation deriving means for deriving a variation in temperature or a variation in deviation between the measured value and the target value of the mill outlet temperature as a mill outlet temperature variation, and an inlet side of the pulverizer Using the upper limit value of the mill inlet temperature, which is the temperature at a fixed position, and the value obtained by converting the mill outlet temperature variation derived by the mill outlet temperature variation deriving means into the variation of the mill inlet temperature. And a mill inlet temperature set value deriving means for deriving a set value of the inlet temperature.

  The processing method in the pulverization plant of the present invention includes a hot air generator that generates hot air as exhaust gas, a pulverizer that pulverizes the raw material and discharges the pulverized raw material to the outside on the flow of the exhaust gas, and the pulverizer A raw material supply device for supplying the raw material to the pulverizer, and a collector for collecting the pulverized raw material released from the pulverizer along the flow of the exhaust gas. A processing method in a pulverization plant for performing a process on a pulverization plant in which control is performed to operate the hot air generator according to a deviation between a measured value of a mill outlet temperature, which is a temperature at a position, and a target value. A mill outlet temperature variation deriving step for deriving a variation in temperature or a variation in a deviation between the measured value and the target value of the mill outlet temperature as a mill outlet temperature variation; Using the upper limit value of the mill inlet temperature, which is the temperature at a fixed position, and the value obtained by converting the mill outlet temperature variation derived by the mill outlet temperature variation deriving step into the variation of the mill inlet temperature. And a mill inlet temperature set value deriving step for deriving a set value of the inlet temperature.

  The program of the present invention causes a computer to function as each means of a processing apparatus in the pulverization plant.

  According to the present invention, the variation of the mill outlet temperature at a certain time, or the variation of the deviation between the measured value of the mill outlet temperature and the target value at the certain time into the variation of the mill inlet temperature, and the mill inlet temperature The upper limit value is used to derive the set value of the mill inlet temperature, and the supply amount that prevents the measured value of the mill inlet temperature from exceeding the set value of the mill inlet temperature is derived as the supply amount per unit time of the raw material. To do. Therefore, it is possible to satisfy both the prevention of the mill inlet temperature from exceeding the upper limit as much as possible and the increase in the supply amount of the raw material as much as possible.

It is a figure which shows an example of a structure of the PCI plant of a negative pressure type and exhaust gas circulation system. It is a figure which shows an example of a function structure of a grinding | pulverization control apparatus. It is a flowchart explaining an example of operation | movement of a grinding | pulverization control apparatus. It is a figure which shows an example of the relationship between the measured value of mill inlet temperature, and time. It is a figure which shows an example of the relationship between the measured value of mill exit temperature, and time. It is a figure which shows an example of the relationship between the standard deviation of mill inlet temperature, and time. It is a figure which shows an example of the relationship between the setting value of mill inlet temperature, and time. It is a figure which shows an example of the relationship between the amount of coal supply in Example 1, and time. It is a figure which shows the relationship between the mill inlet_port | entrance temperature and time in the example of an invention. It is a figure which shows the relationship between the mill inlet_port | entrance temperature and time in the comparative example 1. It is a figure which shows the relationship between the mill inlet_port | entrance temperature and time in the comparative example 2. FIG. It is a figure which shows mill entrance temperature breakthrough frequency. It is a figure which shows an example of the relationship between the amount of coal supply in Example 2, and time. It is a figure which shows the relationship between the mill inlet_port | entrance temperature and time in the comparative example 3. It is a figure which shows the average amount of coal supply. It is a figure which shows an example of a structure of the PCI plant of a 1 pass system.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a case where the pulverization plant is a negative pressure / exhaust gas circulation PCI plant will be described as an example. As will be described later, the application range of the present embodiment is not limited to a negative pressure type / exhaust gas circulation system PCI plant.

(Configuration of PCI plant with negative pressure and exhaust gas circulation system)
FIG. 1 is a diagram showing an example of a configuration of a negative pressure type / exhaust gas circulation system PCI plant. In FIG. 1, a solid line connecting each component indicates piping, and a broken line indicates a signal transmission path. Moreover, an arrow line shows the advancing direction of the gas and coal in piping. Note that the configuration of the negative pressure / exhaust gas circulation system PCI plant can be realized by a known technique such as the technique described in Patent Document 1, for example, so here, each configuration will be briefly described and detailed description will be omitted. To do.

  In FIG. 1, a hot gas generator (HGG) 101 has a burner, controls the air-fuel ratio of the burner using fuel gas and combustion air (air) as inputs to the burner, and generates exhaust gas (hot air). In the present embodiment, BFG (Blast Furnace Gas) is used as the fuel gas. The combustion air is sent to the hot gas generator 101 by the combustion air fan 102.

The bunker 103 stores coal as a raw material.
The coal feeder 104 has a chain conveyor, cuts coal stored in the bunker 103 by the chain conveyor, and puts it into the mill 105.
The mill 105 is a pulverizer that pulverizes coal supplied from the coal feeder 104. By making the pressure at the position on the entry side of the mill 105 maintained at a negative pressure, the pressure inside the mill 105 is maintained at a negative pressure. The mill 105 includes, for example, a roll mill 105a and a crushing table 105b. Coal input from the upper part of the mill 105 is supplied between the roll mill 105a and the crushing table 105b. By rotating the pulverizing table 105b while pressing the roll mill 105a, the coal is crushed and pulverized. The pulverized coal is supplied to the upper part of the mill 105 along the flow of the exhaust gas supplied from the hot gas generator 101, classified by a classifier, and then discharged to the outside.

  At this time, by supplying seal air from the seal air fan 106 to the gap inside the mill 105 (bearing portion of the crushing table 105b), the pulverized coal that is about to be discharged to the outside from the gap is transferred from the hot gas generator 101. Push back into the flow of exhaust gas supplied. The flow rate of the seal air is determined so that the pressure inside the mill 105 is less than the pressure of the seal air. As described above, the pulverized coal enters the bearing portion of the pulverizing table 105b, and as a result, poor lubrication of the bearing portion of the pulverizing table 105b occurs, and the seal air is discharged to the outside from the bearing portion of the pulverizing table 105b. This is to prevent this.

The mill inlet thermometer 120 measures the mill inlet temperature, which is the temperature (in the pipe (gas)) at a predetermined position on the inlet side of the mill 105 (between the hot gas generator 101 and the mill 105).
The bag filter 107 is a filtration type collector that collects pulverized coal discharged from the mill 105 using a filter cloth. Similar to the mill 105, the pressure inside the bag filter 107 is also maintained at a negative pressure. Foreign matter other than pulverized coal may be collected by the bag filter 107. The foreign matter removing device 108 is for removing the foreign matter. After the foreign matter is removed by the foreign matter removing device 108 in this way, pulverized coal is stored in the reservoir tank 109. The pulverized coal stored in the reservoir tank 109 is blown into the blast furnace from the tuyere of the blast furnace (pulverized coal is blown).

The mill outlet thermometer 110 measures a mill outlet temperature which is a temperature (in the pipe (of pulverized coal)) at a predetermined position on the outlet side of the mill 105 (between the mill 105 and the bag filter 107).
The Venturi tube 111 measures the flow rate of the exhaust gas that has passed through the bag filter 107.
The damper 112 adjusts the flow rate of the exhaust gas that has passed through the bag filter 107.
The circulation fan 113 boosts the exhaust gas so that the exhaust gas that has passed through the damper 112 can be circulated to the hot gas generator 101.
A part of the exhaust gas pressurized by the circulation fan 113 is discharged into the atmosphere through the chimney 114. The diffusion system pressure regulating valve 115 is for regulating the pressure of the exhaust gas released into the atmosphere in this way.

  The circulation system pressure adjusting valve 116 is for adjusting the pressure of exhaust gas that is circulated to the hot gas generator 101 without being released into the atmosphere via the chimney 114 among the exhaust gas pressurized by the circulation fan 113. . In this way, the exhaust gas generated in the hot gas generator 101 is supplied again to the hot gas generator 101 as a circulating gas, and the hot gas generator 101, the mill 105, the bag filter 107, the venturi 111, the damper 112, and the circulation. It circulates through the path of the fan 113, the circulation system pressure regulating valve 116, and the hot gas generator 101.

  In the present embodiment, air in the atmosphere (air) is supplied as dilution air to a negative pressure / exhaust gas circulation PCI plant. The orifice flow meter 117 measures the flow rate of the dilution air. The air flow rate adjusting valve 118 is for adjusting the flow rate of dilution air supplied to the negative pressure / exhaust gas circulation system PCI plant. The dilution air fan 119 pressurizes the dilution air whose flow rate is adjusted by the air flow rate adjustment valve 118 and pushes the dilution air into the piping on the inlet side of the hot gas generator 101. Thereby, the oxygen concentration of the circulating gas can be adjusted.

  By performing PID control, the pulverization control device 200 derives a burner load such that the deviation of the mill outlet temperature measured by the mill outlet thermometer 110 from the target value becomes 0 (zero), thereby generating the hot gas generator 101. Output to. Further, the pulverization control device 200 derives a coal feed amount at which the mill inlet temperature measured by the mill inlet thermometer 120 does not exceed the upper limit as much as possible, and outputs it to the coal feeder 104.

(Functional configuration of crushing control device 200)
FIG. 2 is a diagram illustrating an example of a functional configuration of the crushing control device 200. The crushing control device 200 is realized by using, for example, an information processing device (PC) including a CPU, ROM, RAM, HDD, and various interfaces, a programmable logic controller (PLC), and dedicated hardware.

<Mill outlet temperature target value storage unit 201>
The mill outlet temperature target value storage unit 201 stores a target value [° C.] of the mill outlet temperature. The target value of the mill outlet temperature is set by the operator according to the dryness of the pulverized coal.
<Mill outlet temperature measurement value acquisition unit 202>
The mill outlet temperature measurement value acquisition unit 202 acquires the mill outlet temperature [° C.] measured by the mill outlet thermometer 110, for example, at a constant cycle. For example, 1 [minute] can be adopted as the fixed period.

<Mill outlet temperature deviation deriving unit 203>
The mill outlet temperature deviation deriving unit 203 subtracts the measured value of the mill outlet temperature acquired by the mill outlet temperature measured value acquiring unit 202 from the target value of the mill outlet temperature stored in the mill outlet temperature target value storage unit 201. Thus, the deviation [° C.] of the measured value of the mill outlet temperature from the target value is derived. In the following description, the deviation of the measured value of the mill outlet temperature from the target value is referred to as the mill outlet temperature deviation as necessary.

<PID control unit 204>
The PID control unit 204 receives the mill exit temperature deviation derived by the mill exit temperature deviation deriving unit 203, performs proportional operation, integration operation, and differentiation operation, derives a burner load as an operation amount, and generates a hot gas generator By repeating the output to 101, control is performed to bring the measured value of the mill outlet temperature close to the target value (ie, PID control).

<Mill outlet temperature storage unit 205>
The mill outlet temperature storage unit 205 stores the measured value of the mill outlet temperature for a certain time, which is the measured value of the mill outlet temperature acquired by the mill outlet temperature measured value acquisition unit 202. That is, when a new measured value of the mill outlet temperature is acquired by the mill outlet temperature measured value acquisition unit 202, the mill outlet temperature storage unit 205 stores the measured value of the mill outlet temperature stored in the mill outlet temperature storage unit 205. The oldest measured value of the mill outlet temperature is discarded, and the new measured value of the mill outlet temperature is stored. As the fixed time, for example, 1000 [minutes] can be adopted.

<Mill outlet temperature variation deriving unit 206>
The mill outlet temperature variation deriving unit 206 derives the mill outlet temperature variation [° C.] using the measured value of the mill outlet temperature for a predetermined time stored in the mill outlet temperature storage unit 205. In the present embodiment, a case where standard deviation is used as variation will be described as an example. The mill outlet temperature variation deriving unit 206 always derives all the measured values of the mill outlet temperature for a certain period of time stored in the mill outlet temperature storage unit 205 when deriving the standard deviation of the measured value of the mill outlet temperature. There is no need to use.

<Mill inlet temperature variation deriving unit 207>
The mill inlet temperature variation deriving unit 207 multiplies a measured value of the mill outlet temperature derived by the mill outlet temperature variation deriving unit 206 by a value obtained by multiplying the mill inlet temperature by a coefficient for converting the mill outlet temperature into the mill inlet temperature. Derived as an estimated value [° C.] of temperature variation.
In the present embodiment, a coefficient for converting the mill outlet temperature into the mill inlet temperature is determined using the gain of the PID control unit 204.

  When coal is pulverized stably, the target value of the mill outlet temperature is constant, and the measured value of the mill outlet temperature becomes a value close to the target value by the control by the PID control unit 204. On the other hand, the mill inlet temperature varies due to fluctuations in the burner load. This fluctuation of the burner load appears as a result of the control of the mill outlet temperature by the PID control unit 204. Therefore, the larger the gain of the PID control unit 204, the more the burner load is fluctuated. As a result, the variation in the mill inlet temperature also increases. Therefore, in the present embodiment, a coefficient for converting the mill outlet temperature to the mill inlet temperature is determined based on the gain of the PID control unit 204. As a coefficient for converting the mill outlet temperature into the mill inlet temperature, the gain of the PID control unit 204 itself may be used, or a value obtained by adding or subtracting an adjustment value to the gain of the PID control unit 204 may be used. Further, a coefficient for converting the mill outlet temperature into the mill inlet temperature may be determined using the gain of the PID control unit 204 and the integration time.

Further, as described above, in this embodiment, standard deviation is used as the variation.
Therefore, in this embodiment, the mill inlet temperature variation deriving unit 207 derives an estimated value of the standard deviation of the mill inlet temperature from the following equation (1).
Estimated value of standard deviation of mill inlet temperature = standard deviation of measured value of mill outlet temperature × coefficient (1)

<Mill inlet temperature upper limit storage unit 208>
The mill inlet temperature upper limit storage unit 208 stores an upper limit [° C.] of the mill inlet temperature. The upper limit value of the mill inlet temperature is set by the operator within a range where combustion of the expansion and contraction pipes connecting the pipes and ignition of the raw material (coal) supplied to the mill 105 does not occur. The upper limit value of the mill inlet temperature is set, for example, in the range of 300 [° C.] to 400 [° C.].

<Outside temperature acquisition unit 209>
The outside air temperature acquisition unit 209 acquires the current value [° C.] of the outside air temperature. The outside air temperature may be a measured value or an estimated value measured by a thermometer that measures the temperature in the atmosphere. For example, a value obtained by increasing or decreasing a predetermined temperature from the dilution air temperature can be used as an estimated value of the outside air temperature.

<Coal moisture acquisition unit 210>
The coal moisture acquisition unit 210 acquires the current value of the moisture content (per mass) of the coal being crushed (per unit mass). In the following description, the moisture content of coal is referred to as coal moisture as necessary. The coal moisture may be a measured value or an estimated value. For example, the measured value of coal moisture can be obtained as described in JP 2011-133450 A. For example, an estimated value of coal moisture can be obtained as described in JP-A-9-4839. Since the method for obtaining the coal moisture can be realized by a known technique, a detailed description thereof is omitted here. In addition, as described in the specification of Japanese Patent Application No. 2014-189252, the flow rate of fuel gas (BFG), the flow rate of combustion air, the flow rate of dilution air, the gas released from the chimney 114 into the atmosphere (emission) Gas) flow rate, outside air temperature, fuel gas temperature, combustion air temperature, dilution air temperature, and physical quantity including coal moisture as variables, and heat in a PCI plant with negative pressure and exhaust gas circulation system An estimated value of coal moisture can be obtained by calculating a plurality of formulas for calculating the balance of the balance.

<Coal supply acquisition unit 211>
The coal supply amount acquisition unit 211 acquires the current value of the coal supply amount [t / h]. The amount of coal supply is the weight per unit time (here, per hour) of coal supplied from the coal feeder 104 to the mill 105.
In the present embodiment, it is assumed that the operator can manually set the amount of coal supply to the coal feeder 104. The operator, for example, determines the amount of coal to be fed by using whether the production amount based on the operation plan can be achieved and whether the equipment is damaged or not, and according to the determined amount of coal to be fed, for example, The number of rotations of the motor of the chain conveyor provided in the charcoal machine 104 is set. By operating the motor of the chain conveyor at the rotation speed set in this way, coal is supplied to the mill 105 with a desired amount of coal supply.

<Maximum coal supply amount deriving unit 212>
The maximum coal supply amount deriving unit 212 is based on the variation in the mill inlet temperature derived by the mill inlet temperature variation deriving unit 207 and the upper limit value of the mill inlet temperature stored in the mill inlet temperature upper limit storage unit 208. Then, the set value [° C.] of the mill inlet temperature is derived. The set value of the mill inlet temperature is a target value of the mill inlet temperature so that the measured value of the mill inlet temperature does not exceed the upper limit value of the mill inlet temperature.

As described above, in this embodiment, standard deviation is used as the variation. In the present embodiment, it is assumed that the mill inlet temperature varies according to a normal distribution with respect to the steady value. Therefore, in the present embodiment, among the measured values of the mill inlet temperature, a target value at which about 99 [%] is less than or equal to the upper limit value is set as the set value of the mill inlet temperature. From the above, in the present embodiment, the maximum coal supply amount deriving unit 212 derives the set value of the mill inlet temperature from the following equation (2).
Set value of mill inlet temperature = upper limit of mill inlet temperature -3 x estimated value of standard deviation of mill inlet temperature (2)

  Next, the maximum coal supply amount deriving unit 212 receives as input the set value of the mill inlet temperature, the outside air temperature acquired by the outside air temperature acquiring unit 209, and the coal moisture acquired by the coal moisture acquiring unit 210. Then, the maximum possible coal supply amount [t / h] is derived. The maximum coal supply amount is a steady coal supply amount that is maximum in a range where the measured value of the mill inlet temperature does not exceed the set value of the mill inlet temperature.

In the present embodiment, a calculation formula for the maximum possible coal supply amount is determined based on a prediction formula for the mill inlet temperature expressed by the following formula (3).
Predicted value of mill inlet temperature = α × coal feed amount × coal moisture + β × coal feed amount × coal moisture × outside air temperature + γ × coal feed amount × outside air temperature + ε (3)

The equation (3) indicates that the predicted value [° C.] of the mill inlet temperature is considered to affect the amount of coal supplied × moisture, the amount of coal supplied × moisture × outside temperature, and the amount of coal supplied × outside temperature. It is obtained based on. That is, it is based on the heat balance before and after the mill 105. Mill inlet temperature prediction coefficient (moisture latent heat) α [° C / t · h], mill inlet temperature prediction coefficient (moisture sensible heat) β [kcal / (Nm ³ · ° C)], mill inlet temperature prediction coefficient (coal sensible heat) γ [° C./%·t·h] are these coefficients, respectively. The mill inlet temperature prediction coefficient (constant correction) ε [kcal / (Nm ³ · ° C.)] is a correction term.

  The mill inlet temperature prediction coefficients α, β, γ, and ε are values derived, for example, by performing multiple regression analysis using past operation data (for example, operation data for six months). Therefore, the mill inlet temperature prediction coefficients α, β, γ, and ε are set in advance in the maximum coal supply amount deriving unit 212 by the operator.

The following equation (4) is obtained by replacing the predicted value of the mill inlet temperature in equation (3) with the set value of the mill inlet temperature and the amount of coal supply with the maximum coal supplyable amount.
Maximum coal supply amount = (set value of mill inlet temperature−ε) / {(α × coal moisture) + β × coal moisture × outside temperature + γ × outside temperature} (4)
In the present embodiment, the maximum coal supply amount deriving unit 212 derives the maximum coal supply amount by calculating the equation (4).

<Coal feed amount setting unit 213>
The coal supply amount setting unit 213 compares the maximum possible coal supply amount derived by the maximum coal supply amount deriving unit 212 with the coal supply amount (current value) acquired by the coal supply amount acquiring unit 211, Based on the comparison result, it is determined whether or not the setting of the coal supply amount is to be changed. When the coal supply amount is manually changed, information for instructing the change of the coal supply amount setting is output.

In this embodiment, the coal supply amount setting unit 213, when a state where the maximum coal supply amount exceeds the coal supply amount (current value) continues for a certain period of time, the decimal point of the (latest) maximum coal supply amount is calculated. The rounded down value is derived as the change in coal supply. Also, the coal supply amount setting unit 213 rounds down the decimal point of the (latest) maximum coal supply amount even when the maximum coal supply amount is below the (current value) coal supply amount for a certain period of time. Is derived as a change in the amount of coal supplied. Here, in this embodiment, the maximum coal supply amount is the coal supply amount for the predetermined time for determining whether or not the state in which the maximum coal supply amount exceeds the (current value) coal supply amount continues. It is longer than the predetermined time for determining whether or not the state below the amount (current value) continues. For example, 300 [minutes] can be adopted as the former fixed time, and 120 [minutes] can be adopted as the latter fixed time.
In this embodiment, in other cases, the coal supply amount (current value) is not changed.

  The coal supply amount setting unit 213 outputs information instructing change of the coal supply amount so that the coal is supplied from the coal feeder 104 to the mill 105 with the change value derived as described above. When the pulverization control device 200 automatically changes the coal supply amount, the coal supply amount setting unit 213 controls to operate the chain conveyor provided in the coal feeder 104 at the rotation speed corresponding to the derived change value. The signal is transmitted to a chain conveyor provided in the coal feeder 104 or a drive device of the chain conveyor provided in the coal feeder 104. Further, when the operator manually changes the coal supply amount, the coal supply amount setting unit 213 displays information indicating the derived change value. Based on this display, the operator performs an operation for operating the chain conveyor provided in the coal feeder 104 at the rotation speed corresponding to the change value.

(Operation flowchart)
Next, an example of the operation of the crushing control device 200 when performing processing for changing the coal supply amount will be described with reference to the flowchart of FIG.
First, in step S301, the mill outlet temperature measurement value acquisition unit 202 acquires a measurement value of the mill outlet temperature. As described above, the measured value of the mill outlet temperature is repeatedly acquired with a period of 1 [minute], for example. In this case, the flowchart of FIG. 3 is repeatedly performed at a cycle of 1 [minute].

  Next, in step S302, the mill outlet temperature storage unit 205 stores the (latest) measured value of the mill outlet temperature acquired in step S301, and also stores the highest measured value of the mill outlet temperature already stored. Discard the old memorized value of mill outlet temperature. Thereby, the measured value of the mill exit temperature for a fixed time is stored.

Next, in step S303, the mill outlet temperature variation deriving unit 206 uses the measured value of the mill outlet temperature for a certain period of time stored in the mill outlet temperature storage unit 205 to use the standard deviation of the measured value of the mill outlet temperature. Is derived.
Next, in step S304, the mill inlet temperature variation deriving unit 207 derives an estimated value of the standard deviation of the mill inlet temperature by calculating equation (1).

  Next, in step S305, the maximum coal supply amount deriving unit 212 calculates the estimated value of the standard deviation of the mill inlet temperature derived in step S304 and the mill inlet temperature stored in the mill inlet temperature upper limit storage unit 208. Based on the upper limit value, the setting value of the mill inlet temperature is derived by calculating the equation (2).

Next, in step S306, the outside air temperature acquisition unit 209 acquires the current value of the outside air temperature.
Next, in step S307, the coal moisture acquisition unit 210 acquires the current value of coal moisture.
Next, in step S308, the coal supply amount acquisition unit 211 acquires the current value of the coal supply amount.

  Next, in step S309, the maximum coal supply amount deriving unit 212 sets the mill inlet temperature set value derived in step S305, the outside air temperature acquired in step S306, and the coal moisture acquired in step S307. Based on the amount of coal supply acquired in step S308, the maximum amount of coal supply is derived by calculating equation (4).

  Next, in step S310, the coal supply amount setting unit 213 determines whether or not the state where the maximum coal supply amount derived in step S309 exceeds the coal supply amount acquired in step S308 continues for a certain period of time. To do. As a result of the determination, if the state where the maximum coal supply amount exceeds the coal supply amount continues for a certain period of time, the process proceeds to step S311. When the process proceeds to step S311, the coal supply amount setting unit 213 derives a value obtained by rounding down the decimal point of the maximum coal supply amount derived in step S309 as a change value of the coal supply amount. Information for instructing a change in the setting of the amount of coal supply is output so as to be supplied from the coal feeder 104 to the mill 105. And it progresses to step S313 mentioned later.

  In step S310, when it is determined that the state in which the maximum coal supply amount exceeds the coal supply amount does not continue for a certain period of time, the process proceeds to step S312. In step S312, the coal supply amount setting unit 213 determines whether or not the state in which the maximum coal supply amount derived in step S309 is lower than the coal supply amount acquired in step S308 continues for a certain period of time. . As a result of the determination, if the state where the maximum coal supply amount is less than the coal supply amount continues for a certain period of time, the process proceeds to step S311. When the process proceeds to step S311, as described above, the coal supply amount setting unit 213 derives and derives a value obtained by rounding down the decimal portion of the maximum coal supply amount derived in step S309 as a change value of the coal supply amount. Information indicating the change in the setting of the coal supply amount is output so that the coal is supplied from the coal feeder 104 to the mill 105 with the change value. And it progresses to step S313 mentioned later.

On the other hand, when the state where the maximum coal supply amount is less than the coal supply amount has not continued for a certain time, the process proceeds to step S313 without performing the process of step S311. In step S313, the pulverization control device 200 determines whether or not to end the pulverization. This determination can be made, for example, based on information transmitted from a host computer that manages the operation of a negative pressure / exhaust gas circulation system PCI plant.
As a result of this determination, when the pulverization is terminated, the processing according to the flowchart of FIG. 3 is terminated. On the other hand, if the pulverization is not terminated, the process returns to step S301, and steps S301 to S313 are repeated until it is determined that the pulverization is terminated.

(Example)
Next, examples will be described.
FIG. 4 is a diagram showing an example of the relationship between the measured value of the mill inlet temperature and time.
As shown in FIG. 4, in general, the measured value of the mill inlet temperature includes a change in the setting value of the coal supply amount, a change in coal moisture, etc., in addition to a short cycle fluctuation of about 10 [minutes] to 15 [minutes]. A moderate steady-state change due to.

  FIG. 5 is a diagram illustrating an example of the relationship between the measured value of the mill outlet temperature and time. Here, as long as the target value of the mill outlet temperature is constant, as shown in FIG. 5, generally, only a short period of fluctuation occurs in the measured value of the mill outlet temperature (the gentle fluctuation that occurs in the measured value of the mill inlet temperature). Steady state value does not occur).

FIG. 6 is a diagram showing an example of the relationship between the standard deviation of the mill inlet temperature and time.
In FIG. 6, a graph 601 is a graph showing an estimated value of the standard deviation of the mill inlet temperature obtained by calculating the equation (1) from the measured value of the mill outlet temperature shown in FIG. 5. Graph 601 is an invention example. On the other hand, a graph 602 is a graph showing the standard deviation of the mill inlet temperature obtained from the measured value of the mill inlet temperature shown in FIG. A graph 602 is a comparative example.

In this example, the same value (value assumed in actual operation) was used as the coefficient in equation (1) in any case. In any case, the standard deviation was calculated from the latest one-day performance (1440 samples).
As shown in FIG. 4, there is a gradual change in the measured value of the mill inlet temperature. Therefore, as shown in the graph 602, when the standard deviation of the mill inlet temperature is derived from the measured value of the mill inlet temperature, there is a gradual change in the measured value of the mill inlet temperature. The (variation amount) is greatly estimated. On the other hand, as shown in the graph 601, when the standard deviation of the mill inlet temperature is derived from the measured value of the mill outlet temperature shown in FIG. 5, the standard deviation (variation amount) of the mill inlet temperature is excessive compared to the graph 602. Is never estimated. As described above, the measured value of the mill outlet temperature shown in FIG. 5 has only a short-cycle fluctuation (there is no gradual steady-state change that occurs in the measured value of the mill inlet temperature).
In this example, a computer simulation was performed using the measured value of the mill inlet temperature, the measured value of the mill outlet temperature, and the standard deviation of the mill inlet temperature as described above.
<Example 1>
In Example 1, the ratio of the mill inlet temperature exceeding the upper limit was compared in the following three cases.
(A) When the set value of the mill inlet temperature is derived based on the measured value of the mill outlet temperature: Invention example (B) When the set value of the mill inlet temperature is derived based on the measured value of the mill inlet temperature: Comparative example 1
(C) When the set value of the mill inlet temperature is a fixed value: Comparative Example 2

FIG. 7 is a diagram illustrating an example of the relationship between the set value of the mill inlet temperature and time.
In FIG. 7, a graph 701 is a graph showing a set value of the mill inlet temperature obtained by calculating the formula (2) from the estimated value of the standard deviation of the mill inlet temperature of the graph 601 shown in FIG. 6. A graph 701 is an invention example (in the case of (A)). On the other hand, the graph 702 shows the mill inlet temperature obtained by giving the standard deviation of the measured value of the mill inlet temperature in the graph 602 shown in FIG. 6 as the estimated value of the standard deviation of the mill inlet temperature on the right side of the equation (2). It is a graph which shows a setting value. A graph 702 is Comparative Example 1 (in the case of (B)). In this example, the upper limit value of the mill inlet temperature in equation (2) was 350 [° C.] in any case.

  As shown in the graph 702, when the set value of the mill inlet temperature is derived from the standard deviation of the measured value of the mill inlet temperature, the measured value of the mill inlet temperature has a gradual change in steady value (see FIG. 4). The set value of the mill inlet temperature is estimated to be small. On the other hand, as shown in the graph 701, when the set value of the mill inlet temperature is derived from the estimated value of the standard deviation of the mill inlet temperature, the set value of the mill inlet temperature is estimated to be underestimated compared to the graph 702. Absent.

FIG. 8 is a diagram illustrating an example of a relationship between the amount of coal supply and time in the first embodiment.
In FIG. 8, a graph 801 is derived from the set maximum value of the mill inlet temperature in the graph 701 shown in FIG. It is a graph which shows the amount of coal supply set by performing processing of Steps S310-S312. A graph 801 is an example of the invention (in the case of (A) above). The graph 802 derives the maximum possible coal supply amount by calculating the equation (4) from the set value of the mill inlet temperature of the graph 702 shown in FIG. 7, and steps S310 to S312 from the derived maximum possible coal supply amount. It is a graph which shows the amount of coal supply set by performing this process. A graph 802 is Comparative Example 1 (in the case of (B)). The graph 803 derives the maximum coal supplyable amount by calculating the equation (4) with the set value of the mill inlet temperature as a fixed value, and performs the processing of steps S310 to S312 from the derived maximum coal supplyable amount. It is a graph which shows the amount of coal supply set by. A graph 803 is Comparative Example 2 (in the case of (C) described above). In Comparative Example 2 ((C) above), the fixed value was a value that would provide a coal supply amount equivalent to the average value of the coal supply amount shown in the graph 801.
In any case, the fixed time in step S310 is set to 300 [minutes], and the fixed time in step S312 is set to 120 [minutes].

FIG. 9 is a diagram showing the relationship between the mill inlet temperature and time in the invention example.
A graph 901 shown in FIG. 9 is a graph showing a simulation result of the mill inlet temperature. The mill inlet temperature at this time was calculated from the amount of coal supply shown in the graph 801 based on the equation (3). Graph 901 is an example of the invention.
FIG. 10 is a diagram showing the relationship between the mill inlet temperature and time in Comparative Example 1.
A graph 1001 shown in FIG. 10 is a graph showing a simulation result of the mill inlet temperature. The mill inlet temperature at this time was calculated from the amount of coal supply shown in the graph 802 based on the equation (3). A graph 1001 is Comparative Example 1.
FIG. 11 is a diagram showing the relationship between the mill inlet temperature and time in Comparative Example 2.
A graph 1101 shown in FIG. 11 is a graph showing a simulation result of the mill inlet temperature. The mill inlet temperature at this time was calculated from the amount of coal supply shown in the graph 803 based on the formula (3). Graph 1101 is Comparative Example 2.

FIG. 12 is a diagram showing the frequency at which the mill inlet temperature is exceeded.
The mill inlet temperature breakthrough frequency is a ratio [%] of values exceeding the upper limit value of the mill inlet temperature among the values of the graphs 901, 1001, and 1101 shown in FIGS. 9, 10, and 11. As shown in FIG. 12, the mill inlet temperature breakthrough frequency is derived individually for each of the graphs 901, 1001, and 1101.

  As shown in FIG. 12, when securing a high average coal feed rate, rather than setting the set value of the mill inlet temperature to a fixed value (as compared to Comparative Example 2), the estimated value of the standard deviation of the mill inlet temperature is used for the mill inlet. Deriving the temperature setting value (the invention example) has higher equipment maintenance performance, and the mill inlet temperature breakthrough frequency is about 10% of the case where the mill inlet temperature setting value is a fixed value.

<Example 2>
In Example 2, the average coal supply was compared for the following three cases.
(A) When the set value of the mill inlet temperature is derived based on the measured value of the mill outlet temperature: Invention example (B) When the set value of the mill inlet temperature is derived based on the measured value of the mill inlet temperature: Comparative example 1
(D) When the set value of the mill inlet temperature is a fixed value: Comparative Example 3

FIG. 13 is a diagram illustrating an example of the relationship between the amount of coal supply and time in the second embodiment.
In FIG. 13, graphs 1301 and 1302 are the same as the graphs 801 and 802 shown in FIG.
On the other hand, a graph 1303 is a graph when the set value of the mill inlet temperature is a fixed value. A graph 1303 is Comparative Example 3 (in the case of (D) above).

Here, in Comparative Example 3 ((D)), the fixed value is such that the mill inlet temperature breakthrough frequency shown in FIG. 12 is the same value (0.04 [%]) as the invention example. It was.
FIG. 14 is a diagram showing the relationship between the mill inlet temperature and time in Comparative Example 3.
A graph 1401 shown in FIG. 14 is a graph of a predicted value of the mill inlet temperature obtained by performing the calculation of Expression (3) from the coal supply amount shown in the graph 1303. A graph 1401 is Comparative Example 3. The relationship between the mill inlet temperature and time in the inventive example and the comparative example 1 is the same as the graph 901 shown in FIG. 9 and the graph 1001 shown in FIG.

FIG. 15 is a diagram showing the average amount of coal supply.
As shown in FIG. 15, when the set value of the mill inlet temperature is derived from the estimated value of the standard deviation of the mill inlet temperature (that is, in the invention example), the set value of the mill inlet temperature is set to a fixed value (that is, Comparative Example 3). In case of deriving the set value of the mill inlet temperature from the standard deviation of the measured value of the mill inlet temperature (that is, in the case of Comparative Example 1), 5% and 7% higher production quantities are secured, respectively. can do.
From the above Examples 1 and 2, it can be seen that the invention example can achieve both improvement in equipment maintenance performance and increase in the average coal supply compared to the comparative example.

  When the standard deviation of the measured value of the mill inlet temperature is derived (that is, in the case of Comparative Example 1), the change in the steady value of the measured value of the mill inlet temperature as shown in FIG. Amount). For this reason, as shown in FIG. 7, the operation is performed with the mill inlet temperature lowered unnecessarily. As a result, as shown in FIG. 15, the average amount of coal supply decreases. On the other hand, when the standard deviation of the mill inlet temperature is estimated from the measured value of the mill outlet temperature (that is, in the case of the invention example), the standard deviation (variation) of the mill inlet temperature is not affected by such a change in the steady value. Amount). For this reason, compared with the comparative example 1, in the example of an invention, coexistence with maintaining a mill inlet_port | entrance temperature below an upper limit and enlarging a coal supply amount can be aimed at.

(Summary)
As described above, in this embodiment, the standard deviation of the measured value of the mill outlet temperature for a certain time is multiplied by the gain of the PID control to derive the estimated value of the standard deviation of the mill inlet temperature, and the upper limit value of the mill inlet temperature. And a set value of the mill inlet temperature is derived based on the estimated value of the standard deviation of the mill inlet temperature. Then, based on the set value of the mill inlet temperature, the outside air temperature, and the coal moisture, the maximum coal supply amount is derived, and the state where the coal supply amount exceeds or falls below the maximum coal supply amount continues for a certain period of time. In this case, the setting value of the coal supply amount is changed so that the coal supply amount approaches the maximum coal supply amount. In this way, the estimated value of the standard deviation of the mill inlet temperature is derived using the measured value of the mill outlet temperature that is feedback-controlled so as to be the target value. The standard deviation of the mill inlet temperature can be derived without being greatly affected by the above. Therefore, it is possible to accurately predict the variation in the mill inlet temperature so that the mill inlet temperature does not exceed the upper limit as much as possible and to increase the supply amount of raw materials as much as possible. .

(Modification)
<Modification 1>
In this embodiment, the case where the crushing control apparatus 200 is applied to a negative pressure / exhaust gas circulation system PCI plant has been described as an example. However, the pulverization control apparatus 200 can be applied to negative pressure / exhaust gas circulation system pulverization plants other than the negative pressure / exhaust gas circulation system PCI plant. For example, the pulverization control apparatus 200 can be applied to a negative pressure / exhaust gas circulation pulverization plant for producing cement.

<Modification 2>
In the present embodiment, the case where the pulverization plant is a negative pressure exhaust gas circulation system pulverization plant has been described as an example. However, the grinding plant may be a one-pass grinding plant.
FIG. 16 is a diagram illustrating an example of the configuration of a one-pass PCI plant. In FIG. 16, the same reference numerals as those in FIG. 1 are assigned to the same parts as those of the negative pressure / exhaust gas circulation system PCI plant shown in FIG. Also in FIG. 16, as in FIG. 1, the solid lines connecting the components indicate piping, and the broken lines indicate signal transmission paths. Moreover, an arrow line shows the advancing direction of the gas and coal in piping.

In FIG. 16, a hot gas generator (HGG) 101 controls the air-fuel ratio of the burner to generate exhaust gas (hot air). The combustion air fan 102 is a fan that increases the pressure in order to send the combustion air to the hot gas generator 101.
The damper 121 adjusts the flow rate of the exhaust gas discharged from the hot gas generator 101.
The mill inlet thermometer 120 measures the mill inlet temperature, which is the temperature (in the pipe (gas)) at a predetermined position on the inlet side of the mill 105 (between the hot gas generator 101 and the damper 121).

The supply fan 122 is a fan that boosts the exhaust gas in order to supply the exhaust gas that has passed through the damper 121 to the mill 105.
The bunker 103 stores coal as a raw material.
The coal feeder 104 has a chain conveyor, cuts coal stored in the bunker 103 by the chain conveyor, and puts it into the mill 105.

The mill 105 is a pulverizer that pulverizes coal supplied from the coal feeder 104. The mill 105 includes, for example, a roll mill 105a and a crushing table 105b.
The seal air fan 106 supplies seal air to the gap inside the mill 105 (bearing portion of the grinding table 105b).

The bag filter 107 is a filtration type collector that collects pulverized coal discharged from the mill 105 using a filter cloth.
The foreign matter removing device 108 is for removing the foreign matter. After the foreign matter is removed by the foreign matter removing device 108 in this way, pulverized coal is stored in the reservoir tank 109. The pulverized coal stored in the reservoir tank 109 is blown into the blast furnace from the tuyere of the blast furnace (pulverized coal is blown).

In the negative pressure type / exhaust gas circulation system PCI plant, the pressure inside the mill 105 and the bag filter 107 is kept at a negative pressure. In the one-pass type PCI plant, the pressure inside the mill 105 and the bag filter 107 is Atmospheric pressure.
The exhaust gas that has passed through the bag filter 107 is released into the atmosphere through the chimney 123.
Even in a one-pass PCI plant, the configuration and processing of the crushing control device 200 can be realized by the same one as described in the present embodiment.

<Modification 3>
In the present embodiment, the case where the mill outlet temperature control and the coal supply amount control are performed by one apparatus (grinding control apparatus 200) has been described as an example. However, this is not always necessary. For example, the mill outlet temperature control and the coal supply amount control may be performed by separate devices. In this case, for example, the pulverization control device 200 has a function of controlling the mill outlet temperature (a mill outlet temperature target value storage unit 201, a mill outlet temperature measurement value acquisition unit 202, a mill outlet temperature deviation derivation unit 203, and a PID. This function may be realized by another device that can communicate with the crushing control device 200.

<Modification 4>
In the present embodiment, the case where the standard deviation is derived as the variation in the mill outlet temperature has been described as an example. However, if an index representing variation used in a general statistical method is used, the variation in the mill outlet temperature is not limited to the standard deviation. In this case, the estimated value of the variation in the mill inlet temperature is also the estimated value of the same index as the index representing the variation selected as the variation in the mill outlet temperature.

<Modification 5>
In this embodiment, the case where the coefficient for converting the mill outlet temperature into the mill inlet temperature is a coefficient set on the basis of the gain of PID control has been described as an example. However, the coefficient for converting the mill outlet temperature to the mill inlet temperature is not limited to a coefficient set on the basis of the gain of PID control. For example, when the mill outlet temperature control is performed by feedback control other than the PID control, the coefficient for converting the mill outlet temperature to the mill inlet temperature is set with reference to the control gain in the controller that performs the feedback control. A coefficient may be used. Further, the relationship between the mill outlet temperature and the mill inlet temperature may be investigated in advance, and the coefficient may be set from the result of the investigation.

<Modification 6>
In the present embodiment, an example in which a value obtained by subtracting a value (3σ) obtained by multiplying the estimated value of the standard deviation of the mill inlet temperature by “3” from the upper limit value of the mill inlet temperature is derived as the setting value of the mill inlet temperature. And explained. However, the set value of the mill inlet temperature is not necessarily derived in this way. For example, “2” may be used instead of “3” described above. Further, the set value of the mill inlet temperature may be derived assuming that the mill inlet temperature varies according to a distribution other than the normal distribution with respect to the steady value. In other words, based on the upper limit value of the mill inlet temperature and the estimated value of the variation of the mill inlet temperature, the target value of the mill inlet temperature so that the predetermined ratio of the measured value of the mill inlet temperature is not more than the upper limit value. May be derived as the set value of the mill inlet temperature.

<Modification 7>
In this embodiment, the case where the variation (standard deviation) of the measured value of the mill outlet temperature for a certain time (for example, 1000 [min]) is derived has been described as an example. However, this is not always necessary. For example, you may derive the dispersion | variation (standard deviation) for a fixed time of mill exit temperature deviation. In this way, for example, even if there is a change in the target value of the mill outlet temperature, the variation in the mill outlet temperature before and after the change can be compared as it is.

<Modification 8>
In the present embodiment, the coal supply amount acquisition unit 211 has been described by taking as an example the case of acquiring the coal supply amount manually set by the operator. However, this is not always necessary. For example, the coal supply amount acquisition unit 211 may receive the coal supply amount from a host computer.

<Modification 9>
In the present embodiment, the case where the coefficients are multiplied by the equations (1) and (2) has been described as an example. However, an estimated value of the standard deviation of the mill inlet temperature may be derived using a value obtained by multiplying the coefficients of the expressions (1) and (2) as one coefficient. For example, the estimated value of the standard deviation of the mill inlet temperature may be derived from the following equation (5).
Estimated value of standard deviation of mill inlet temperature = upper limit value of mill inlet temperature-coefficient x standard deviation of measured value of mill outlet temperature (5)
The coefficient in the equation (5) is, for example, a value obtained by multiplying the coefficient shown in the equation (1) by “3” shown in the equation (2).
In this case, the mill inlet temperature variation deriving unit 207 is not necessary. Further, the value of the second term (3 × the estimated value of the standard deviation of the mill inlet temperature) on the right side of the equation (2) may be derived by the mill inlet temperature variation deriving unit 207.

<Modification 10>
In the present embodiment, the coal supply amount setting unit 213 determines the (latest) maximum coal supply amount when the maximum coal supply amount exceeds or falls below (the current value of) the coal supply amount for a certain period of time. An example in which a value obtained by rounding down the decimal point is derived as a change value of the coal supply amount has been described. However, the method of deriving the change value of the coal supply amount is not limited to such a method as long as the change value of the coal supply amount is derived based on the maximum coal supplyable amount. For example, there are various methods other than the above-described methods for changing the setting value of the coal supply amount so that the coal supply amount approaches the maximum coal supply amount. Further, the coal supply amount may not be close to the maximum coal supplyable amount, and the coal supply amount may be close to a value lower than the maximum coal supplyable amount by a predetermined value.
Further, the set value of the mill inlet temperature may be displayed, and the operator may manually set the coal supply amount based on the set value of the mill inlet temperature.

<Other variations>
The embodiment of the present invention described above can be realized by a computer executing a program. Further, a computer-readable recording medium in which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
In addition, the embodiments of the present invention described above are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

(Relationship with claims)
The hot air generator is realized by the hot gas generator 101, for example.
The pulverizer is realized by a mill 105, for example.
The collector is realized by a bug filter 107, for example.
The processing device is realized by the crushing control device 200, for example.
The mill outlet temperature variation deriving unit is realized by, for example, the mill outlet temperature variation deriving unit 206 (processing in step S303).
The mill inlet temperature set value deriving means is realized by, for example, the maximum coal supply possible amount deriving unit 212 (processing in step S305).
The mill inlet temperature variation deriving unit is realized by, for example, the mill inlet temperature variation deriving unit 207 (processing in step S304).
The raw material supply amount deriving unit is realized by, for example, the coal supply amount setting unit 213 (processing in step S311).
The maximum raw material supplyable amount deriving unit is realized by, for example, the maximum coal supplyable amount deriving unit 212 (processing in step S309). The maximum raw material supplyable amount corresponds to, for example, the maximum coal supplyable amount.

  101: Hot gas generator, 103: Bunker, 104: Coal feeder, 105: Mill, 110: Mill outlet thermometer, 200: Grinding control device, 201: Mill outlet temperature target value storage unit, 202: Mill outlet temperature measurement Value acquisition unit, 203: Mill outlet temperature deviation deriving unit, 204: PID control unit, 205: Mill outlet temperature storage unit, 206: Mill outlet temperature variation deriving unit, 207: Mill inlet temperature variation deriving unit, 208: Mill inlet temperature Upper limit storage unit, 209: outside air temperature acquisition unit, 210: coal moisture acquisition unit, 211: coal supply amount acquisition unit, 212: maximum coal supply amount derivation unit, 213: coal supply amount setting unit

Claims (8)

A hot air generator for generating hot air as exhaust gas;
A pulverizer that pulverizes the raw material and discharges the pulverized raw material to the exhaust gas flow;
A raw material supply device for supplying the raw material to the pulverizer;
A collector that collects the pulverized raw material released from the pulverizer while riding on the flow of the exhaust gas, and
In a pulverization plant that performs processing on a pulverization plant in which control is performed to operate the hot air generator according to a deviation between a measured value of a mill outlet temperature, which is a temperature at a predetermined position on the outlet side of the pulverizer, and a target value. A processing device comprising:
Mill outlet temperature variation derivation means for deriving variation in the mill outlet temperature, or variation in deviation between the measured value and the target value of the mill outlet temperature as mill outlet temperature variation;
An upper limit value of the mill inlet temperature, which is a temperature at a predetermined position on the inlet side of the pulverizer, and a value obtained by converting the mill outlet temperature variation derived by the mill outlet temperature variation deriving means into the mill inlet temperature variation. And a mill inlet temperature set value deriving means for deriving a set value of the mill inlet temperature using a processing apparatus.   Using the mill outlet temperature variation derived by the mill outlet temperature variation deriving means and a coefficient for converting the mill outlet temperature into the mill inlet temperature, an estimated value of the mill inlet temperature variation is obtained as the mill The processing apparatus in a pulverization plant according to claim 1, further comprising mill inlet temperature variation deriving means for deriving the outlet temperature variation as a value converted into the mill inlet temperature variation.   The mill inlet temperature set value deriving unit uses the estimated value of the mill inlet temperature variation derived by the mill inlet temperature variation deriving unit and the upper limit value of the mill inlet temperature to calculate the mill inlet temperature. The pulverization plant according to claim 2, wherein a target value of the mill inlet temperature for causing a predetermined ratio of measured values to be equal to or less than the upper limit value is derived as a set value of the mill inlet temperature. Processing equipment.   The processing in the crushing plant according to claim 2 or 3, wherein the coefficient for converting the mill inlet temperature into the mill outlet temperature is a coefficient derived using a control gain in a controller that performs the control. apparatus.   As the supply amount per unit time of the raw material supplied from the raw material supply device to the pulverizer, the measured value of the mill inlet temperature is set to the mill inlet temperature derived by the mill inlet temperature setting value deriving means. The processing apparatus for a pulverization plant according to any one of claims 1 to 4, further comprising raw material supply amount deriving means for deriving a supply amount that does not exceed a value. Using the set value of the mill inlet temperature derived by the mill inlet temperature set value deriving means, the outside air temperature, and the amount of moisture per unit mass contained in the raw material, the measured value of the mill inlet temperature is Maximum raw material supplyable amount deriving means for deriving a maximum raw material supplyable amount that is a maximum supply amount per unit time of the raw material that can be supplied from the raw material supply device to the pulverizer within a range not exceeding the set value of the mill inlet temperature. In addition,
The pulverization plant according to claim 5, wherein the raw material supply amount deriving unit derives the supply amount based on the maximum raw material supplyable amount derived by the maximum raw material supplyable amount deriving unit. Processing equipment. A hot air generator for generating hot air as exhaust gas;
A pulverizer that pulverizes the raw material and discharges the pulverized raw material to the exhaust gas flow;
A raw material supply device for supplying the raw material to the pulverizer;
A collector that collects the pulverized raw material released from the pulverizer while riding on the flow of the exhaust gas, and
In a pulverization plant that performs processing on a pulverization plant in which control is performed to operate the hot air generator according to a deviation between a measured value of a mill outlet temperature, which is a temperature at a predetermined position on the outlet side of the pulverizer, and a target value. A processing method,
Mill outlet temperature variation derivation step for deriving variation in the mill outlet temperature or variation in deviation between the measured value and the target value of the mill outlet temperature as mill outlet temperature variation;
An upper limit value of the mill inlet temperature, which is a temperature at a predetermined position on the inlet side of the pulverizer, and a value obtained by converting the mill outlet temperature variation derived by the mill outlet temperature variation derivation step into the mill inlet temperature variation. And a mill inlet temperature set value derivation step for deriving a set value of the mill inlet temperature using a, and a processing method in a pulverization plant.   A program that causes a computer to function as each means of a processing apparatus in a crushing plant according to any one of claims 1 to 6.

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