JP6809350B2 - Hot air furnace control calculation device, hot air furnace control calculation method, and program - Google Patents

Description

The present invention relates to a hot blast furnace control calculation device, a hot blast furnace control calculation method, and a program, and is particularly suitable for use in controlling a hot blast furnace.

A hot air furnace is attached to the blast furnace to supply hot air to the blast furnace. The hot blast furnace supplies hot air to the blast furnace by alternately repeating the combustion period and the blast period, with the period including one combustion period and one blast period as one cycle based on the blast conditions required by the blast furnace. Is. The combustion period is a period in which heat storage bricks are heated by combustion gas to store heat. During the ventilation period, cold air is passed through the heat storage brick to exchange heat with the heat storage brick to generate hot air and supply it to the blast furnace.

As a technique for controlling the operation of the combustion period in this type of hot air furnace, there are the techniques described in Patent Documents 1 and 2. In the techniques described in Patent Documents 1 and 2, the amount of heat input to the heat storage brick in the next combustion period is derived. Then, in the next combustion period, the flow rate of the combustion gas is adjusted so as to be the derived heat input amount.

JP-A-2009-84620 Japanese Unexamined Patent Publication No. 2013-95946 Japanese Patent No. 5733148 JP 2015-117389 Japanese Patent No. 5803810 Japanese Patent No. 4734014

However, in the techniques described in Patent Documents 1 and 2, the flow rate of the combustion gas in the next combustion period is adjusted by using only the amount of heat input to the heat storage brick in the next combustion period as an index. Therefore, the thermal efficiency of the hot air furnace may decrease. Then, there is a risk of supplying an excessive amount of combustion gas to the heat storage brick. This may increase the cost of the combustion gas.

The present invention has been made in view of the above problems, and an object of the present invention is to appropriately set a target value of a flow rate of combustion gas in the next combustion period.

The hot air furnace control calculation device of the present invention is a hot air furnace having a heat storage chamber and a combustion chamber, and operates with a period including a first switching period, a combustion period, a second switching period, and a blowing period as one cycle. A hot air furnace control calculation device that performs calculations for controlling the operation of the hot air furnace, and is a target combustion pattern deriving means for deriving a target value of a gas flow pattern for the next combustion period during the first switching period. And a combustion pattern acquisition means for acquiring the calculated value of the input heat amount to the hot air furnace in the next combustion period, and a combustion pattern acquisition means for acquiring the calculated value of the gas flow rate pattern in the next combustion period. The combustion period is a period in which the heat storage bricks arranged in the heat storage chamber are heated by combustion gas to store heat, and the ventilation period is a period in which cold air is passed through the heat storage bricks to generate hot air by heat exchange with the heat storage bricks. The first switching period is a preparation period for shifting from the blast period to the combustion period, and the second switching period is from the combustion period to the blast period. The gas flow rate pattern shows the relationship between the flow rate of the combustion gas and the time, and the target combustion pattern derivation means is the heat input to the hot air furnace during the previous combustion period. Based on the calculated value of the amount of heat input to the hot air furnace in the next combustion period, the calculated value of the gas flow rate pattern in the next combustion period, and the gas flow rate pattern in the previous combustion period, the next time. It is characterized by deriving a target value of a gas flow pattern during the combustion period of.

The hot air furnace control calculation method of the present invention is a hot air furnace having a heat storage chamber and a combustion chamber, and operates with a period including a first switching period, a combustion period, a second switching period, and a blowing period as one cycle. This is a hot air furnace control calculation method for performing calculations for controlling the operation of the hot air furnace, and is a target combustion pattern derivation step for deriving a target value of a gas flow pattern for the next combustion period during the first switching period. It also has an input heat amount acquisition step of acquiring a calculated value of the input heat amount to the hot air furnace in the next combustion period, and a combustion pattern acquisition step of acquiring a calculated value of a gas flow rate pattern in the next combustion period. The combustion period is a period in which the heat storage bricks arranged in the heat storage chamber are heated by combustion gas to store heat, and the ventilation period is a period in which cold air is passed through the heat storage bricks to generate hot air by heat exchange with the heat storage bricks. The first switching period is a preparation period for shifting from the blast period to the combustion period, and the second switching period is from the combustion period to the blast period. The gas flow rate pattern shows the relationship between the flow rate of the combustion gas and the time, and the target combustion pattern derivation step is the heat input to the hot air furnace during the previous combustion period. Based on the calculated value of the amount of heat input to the hot air furnace in the next combustion period, the calculated value of the gas flow rate pattern in the next combustion period, and the gas flow rate pattern in the previous combustion period, the next time. It is characterized by deriving a target value of a gas flow pattern during the combustion period of.

The program of the present invention is characterized in that a computer functions as each means of the hot air furnace control calculation device.

According to the present invention, the target value of the flow rate of the combustion gas in the next combustion period can be appropriately set.

FIG. 1 is a diagram showing an example of a schematic configuration of a hot air furnace. FIG. 2 is a diagram showing an outline of the operation of the combustion period and the ventilation period in the hot air furnace. FIG. 3 is a diagram showing an example of a schematic configuration of a hot air furnace control system. FIG. 4 is a diagram illustrating an outline example of an operation schedule in the staggered parallel system. FIG. 5 is a diagram showing an example of the functional configuration of the hot air furnace control calculation device. FIG. 6 is a diagram illustrating an example of an outline of the functions of the hot air furnace control calculation device. FIG. 7 is a diagram showing an example of a detailed functional configuration of the input heat amount acquisition unit. FIG. 8 is a diagram conceptually showing an example of the target silica stone brick minimum temperature for each furnace and each cycle and the operation target value (operation condition). FIG. 9 shows the target minimum temperature of silica stone bricks by furnace and cycle, the predicted value of the minimum temperature of silica stone bricks by furnace and cycle, the operation target value (operating conditions), and the amount of heat input by furnace and cycle. It is a figure which shows an example conceptually. FIG. 10 is a diagram showing an example of a detailed functional configuration of the second process state prediction unit. FIG. 11 is a diagram showing an example of a detailed functional configuration of the combustion pattern acquisition unit. FIG. 12 is a diagram showing an example of a combustion pattern. FIG. 13 is a diagram showing an example of a Pareto optimal solution. FIG. 14 is a diagram showing an example of a GUI for causing the operator to change the Pareto optimal solution. FIG. 15 is a diagram conceptually explaining a modified example of the method of automatically selecting the Pareto optimum solution. FIG. 16 is a diagram showing an example of a detailed functional configuration of the target combustion pattern derivation unit. FIG. 17 is a diagram illustrating an example of a method for deriving a target dome temperature pattern. FIG. 18 is a diagram illustrating an example of a method of changing the target dome temperature pattern. FIG. 19 is a diagram illustrating an example of a method for deriving a target combustion pattern of the C / B ratio. FIG. 20 is a diagram illustrating an example of the first step of the method of deriving the target BFG flow rate. FIG. 21 is a diagram illustrating an example of the second stage of the method of deriving the target BFG flow rate. FIG. 22 is a diagram illustrating an example of a method of changing the target combustion pattern of the BFG flow rate. FIG. 23A is a flowchart illustrating an example of the operation of the target combustion pattern derivation unit. FIG. 23B is a flowchart illustrating an example of the operation of the target combustion pattern derivation unit following FIG. 23A. FIG. 23C is a flowchart illustrating an example of the operation of the target combustion pattern derivation unit following FIG. 23B. FIG. 24 is a diagram illustrating a modified example of the method of changing the target dome temperature pattern.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Structure of hot air furnace 100]
FIG. 1 is a diagram showing an example of a schematic configuration of a hot air furnace 100. In each figure, for convenience of explanation, only necessary parts are shown in a simplified manner as necessary.
In FIG. 1, the hot air furnace 100 is a heat storage type heat exchanger for supplying hot air to a blast furnace (not shown). The hot air furnace 100 has a heat storage chamber 101, a combustion chamber 102, and a mixing / cooling chamber 103. The heat storage chamber 101 is a facility for giving heat to the air blown to the blast furnace. The combustion chamber 102 is a facility for heating the heat storage chamber 101. The mixing / cooling chamber 103 is a facility for controlling the temperature of hot air. There is also a hot air furnace in which the mixing / cooling chamber 103 does not exist. The hot air furnace control system of the present embodiment can be applied to a hot air furnace in which the mixing / cooling chamber 103 does not exist.

In the combustion chamber 102, the mixed gas of BFG (Blast Furnace Gas), COG (Coke Oven gas) and LNG (Liquefied Natural Gas) blown from the gas supply duct 112, and the combustion-fueled air blown from the combustion-fuel-fuel supply duct 113 are introduced. It is burned with a combustion burner 108. In the following description, this mixed gas is collectively referred to as a combustion gas, if necessary. This combustion gas is passed between the heat storage bricks laminated inside the heat storage chamber 101 to heat the heat storage bricks. As a result, the heat storage brick stores heat. A dome thermometer 135 is attached to the upper part of the heat storage chamber 101. The dome thermometer 135 measures the dome temperature. The dome temperature is the temperature of the dome located above the heat storage chamber 101.

In the example shown in FIG. 1, as heat storage bricks, clay bricks 109, high alumina bricks 110, and silica stone bricks 111 are laminated in this order from the bottom. The clay brick 109, the high alumina brick 110, and the silica stone brick 111 are formed with a plurality of passage ports extending in the vertical direction. A high alumina brick thermometer 136 is attached to the high alumina brick 110. The high alumina brick thermometer 136 measures the temperature of the high alumina brick 110. A silica brick thermometer 137 is attached to the silica stone brick 111. The silica stone brick thermometer 137 measures the temperature at the lower end of the silica stone brick 111.

The gas supply duct 112 is provided with a gas shutoff valve 130.
The portion of the gas supply duct 112 on the upstream side (right side in FIG. 1) of the gas shutoff valve 130 branches into the BFG supply duct 141 and the COG supply duct 142.
The BFG supply duct 141 is connected to a blast furnace (not shown). The BFG supply duct 141 blows the BFG generated in the blast furnace to the hot air furnace 100.

The BFG supply duct 141 is provided with a BFG flow rate control valve 131 and a BFG flow meter 132. By opening and closing the BFG flow rate control valve 131, the inflow amount of BFG flowing into the hot air furnace 100 can be adjusted. Further, based on the measurement result of the BFG flow meter 132, the inflow amount of BFG flowing into the hot air furnace 100 can be monitored.

The COG supply duct 142 is usually connected to a coke oven (not shown). The COG supply duct 142 blows the COG generated in the coke oven to the hot air furnace 100.
The COG supply duct 142 is provided with a COG flow rate control valve 133 and a COG flow meter 134. By opening and closing the COG flow rate control valve 133, the inflow amount of COG flowing into the hot air furnace 100 can be adjusted. Further, the inflow amount of COG flowing into the hot air furnace 100 can be monitored based on the measurement result of the COG flow meter 134.

The combustion assisting air supply duct 113 blows the air blown from the combustion air fan to the hot air furnace 100.
The combustion assisting air supply duct 113 is provided with an air flow meter 127, an air butterfly valve 128, and an air shutoff valve 129. An amount of air required for combustion flows into the combustion assisting air supply duct 113 according to the flow rate of the combustion gas.
A duct 114 is provided at the lower end of the heat storage chamber 101. The duct 114 is branched into a gas discharge duct 119 and a cold air introduction duct 116. The gas discharge duct 119 is a duct for discharging combustion gas containing N ₂ , CO _{2, and the} like. The cold air introduction duct 116 is a duct for supplying cold air to the heat storage chamber 101 via the duct 114.
The gas discharge duct 119 is provided with a gas discharge amount control valve 126, an exhaust gas flow meter 143, and an exhaust gas thermometer 138. By opening and closing the gas discharge amount control valve 126, the amount of combustion gas discharged from the gas discharge duct 119 can be adjusted. In addition, the amount of combustion gas discharged from the gas discharge duct 119 can be monitored based on the measurement result of the exhaust gas flow meter 143. The exhaust gas flow meter 143 measures the amount of CO ₂ gas discharged to the gas discharge duct 119. Further, the temperature of the combustion gas, that is, the exhaust gas temperature can be monitored based on the measurement result of the exhaust gas thermometer 138.

The cold air introduction duct 116 is provided with a blow valve 124 and a blow butterfly valve 125. By opening and closing the blower butterfly valve 125, the amount of cold air flowing into the hot air furnace 100 can be adjusted.
A hot air discharge duct 117 is connected to the mixing / cooling chamber 103. The hot air discharge duct 117 is a duct for discharging hot air for a blast furnace. A hot air valve 121 is provided in the hot air discharge duct 117.
A duct 118 connected to the cooling / cooling chamber 103 is provided on the upstream side (left side in FIG. 1) of the blower butterfly valve 125 of the cold air introduction duct 116. A cold air valve 122 and a cold air butterfly valve 123 are provided in the duct 118. By opening and closing the cold air butterfly valve 123, the amount of cold air flowing into the mixing / cooling chamber 103 can be adjusted.

FIG. 2 is a diagram showing an outline of the operation of the combustion period and the ventilation period in the hot air furnace 100.
As shown in FIG. 2A, when heat is stored in the heat storage chamber 101 during the combustion period, the blow valve 124, the cold air valve 122, and the hot air valve 121 are completely closed. After that, the combustion gas and the combustion assisting air are made to flow into the combustion chamber 102 through the gas supply duct 112 and the combustion assisting air supply duct 113.
The combustion gas and auxiliary air are burned by the combustion burner 108. The combustion gas stores heat in the clay brick 109, the high alumina brick 110, and the silica stone brick 111 through the openings formed in the clay brick 109, the high alumina brick 110, and the silica stone brick 111 in the heat storage chamber 101. The combustion gas that has passed through the clay brick 109, the high alumina brick 110, and the silica stone brick 111 is discharged to the flue as exhaust gas through the gas discharge duct 119. Normally, the minimum temperature at the bottom of the silica stone brick 111 is controlled so as not to be lower than the transformation point temperature. Further, the lower limit of the temperature at the lowermost part of the clay brick 109 is controlled to a constant value (as low as possible so that the exhaust gas temperature does not rise). Further, in the following description, the minimum temperature of the lower end portion of the silica stone brick 111 at the end of the ventilation period is abbreviated as "silica stone brick minimum temperature" as necessary.

When the heat storage in the heat storage chamber 101 is completed, the gas discharge amount control valve 126, the air shutoff valve 129, and the gas shutoff valve 130 are completely closed as shown in FIG. 2B. After that, the cold air is made to flow into the heat storage chamber 101 through the cold air introduction duct 116. The cold air flowing into the heat storage chamber 101 passes through the openings formed in the clay brick 109, the high alumina brick 110, and the silica stone brick 111 and is heated to 900 to 1300 ° C., and then the hot air discharge duct 117 is used as hot air for the blast furnace. Is discharged from.

FIG. 3 is a diagram showing an example of a schematic configuration of a hot air furnace control system. In FIG. 3, the solid line shows the signal flow. The broken line indicates the flow of cold air, hot air, combustion gas, and auxiliary air.
In FIG. 3, a case where four hot air furnaces 100a to 100d are attached to one blast furnace is shown as an example. These four hot air furnaces 100a to 100d shall be operated in a staggered parallel system.
In FIG. 3, there are a hot air thermometer 310, a blower flow meter 307, and a cold air thermometer 308 as measuring instruments provided for each of the four hot air furnaces 100a to 100d. The hot air thermometer 310 measures the temperature of hot air (blower temperature) discharged from the hot air furnaces 100a to 100d to the blast furnace. The blower flow meter 307 measures the flow rate of cold air blown from the blower 306 (cold air flow rate). The cold air thermometer 308 measures the temperature of the cold air blown from the blower 306.

FIG. 4 is a diagram illustrating an outline example of an operation schedule in the staggered parallel system.
In the example shown in FIG. 4, switching from blast to combustion, combustion, switching from combustion to blast, and blast are performed in this order. A period obtained by combining these periods constitutes one cycle (for example, refer to the portion of "1 cycle = switching period 401a + combustion period 402a + switching period 401b + blowing period 403a" shown in FIG. 4). One cycle is, for example, 180 [min]. Then, a part of the blowing time of the two units (for example, the hot air furnace 1 and the hot air furnace 2) that are adjacent to each other in the order of supplying the hot air is wrapped. Further, in the example shown in FIG. 4, the ventilation time and the combustion time are set to the same length for the sake of simplicity. Therefore, for two units that are not adjacent to each other in the order of supplying hot air (for example, hot air furnace 1 and hot air furnace 3), when one hot air furnace is in the blowing period, the other hot air furnace is in the combustion period. Further, when one hot air furnace is in the combustion period, the other hot air furnace is in the air blowing period. Further, in the present embodiment, the case where the blowing time is the same in all the cycles will be described as an example. The switching periods 401a, 401c, and 401e are preparation periods for shifting from the ventilation period to the combustion period. The switching periods 401b and 401d are preparation periods for shifting from the combustion period to the ventilation period.

[Configuration of control device 300]
Returning to the description of FIG. 3, the hot air furnace control system includes a control device 300 that controls the operation of the hot air furnaces 100a to 100d. The control device 300 includes a hot air furnace control calculation device 301, an input / output device 302, a flow rate controller 304a to 304d, a temperature controller 305, and an opening degree controller 313a to 313d.
The hot air furnace control calculation device 301 performs calculations for controlling the operation of the hot air furnaces 100a to 100d based on preset input data and information indicating the operation results. Data is input to the hot air furnace control calculation device 301 via the input / output device 302 which is an interface unit. The operation results include the values measured by the above-mentioned measuring instruments. In FIG. 3, as described above, the hot air furnaces 100a to 100d have a heat storage chamber 101a to 101d, a combustion chamber 102a to 102d, and a mixing and cooling chamber 103a to 103d, respectively.

The outline of an example of the processing performed by the hot air furnace control calculation device 301 will be described below.
In the present embodiment, the hot air furnace control calculation device 301 derives a target combustion pattern of the BFG flow rate for each furnace, a target combustion pattern for the C / B ratio for each furnace, and a target combustion pattern for the dome temperature for each furnace. To do. By furnace means every hot air furnace 100a to 100d. The C / B ratio is the ratio of the flow rate of COG to the flow rate of BFG. The target combustion pattern of the BFG flow rate for each furnace, the target combustion pattern for the C / B ratio for each furnace, and the target combustion pattern for the dome temperature for each furnace are derived at the end of the ventilation periods 403a and 403b. The end of the ventilation periods 403a and 403b refers to a predetermined timing within the switching periods 401c and 401d between the end of the ventilation periods 403a and 403b and the start of the next combustion periods 402b and 402c. For convenience of notation, only the combustion periods 402b and 402c have been described here as the next combustion periods 402b and 402c. However, the other combustion periods shown in FIG. 4 can also be the next combustion period.

The target combustion pattern of the BFG flow rate for each furnace is the target of the relationship between the BFG flow rate and the time in the next combustion period of each hot air furnace 100a to 100d. The target combustion pattern of the dome temperature for each furnace is the target of the relationship between the dome temperature and the time in the next combustion period of each hot air furnace 100a to 100d. The target combustion pattern of the C / B ratio for each furnace is the initial target value of the C / B ratio in the next combustion period of each hot air furnace 100a to 100d.

In the following description, the target combustion pattern of the BFG flow rate for each furnace, the target combustion pattern for the C / B ratio for each furnace, and the target combustion pattern for the dome temperature for each furnace are described as necessary for the target BFG flow rate. It is called the target combustion pattern of the above, the target combustion pattern of the C / B ratio, and the target combustion pattern of the dome temperature. Further, when the target combustion pattern of the BFG flow rate, the target combustion pattern of the C / B ratio, and the target dome temperature pattern are collectively referred to, these are simply referred to as the target combustion patterns. Further, when the flow rate of BFG for each furnace, the C / B ratio for each furnace, and the dome temperature for each furnace are collectively referred to, these are simply referred to as combustion patterns, if necessary.

The hot air furnace control calculation device 301 outputs the target combustion pattern of the BFG flow rate, the target combustion pattern of the dome temperature, and the target combustion pattern of the C / B ratio to the flow rate controllers 304a to 304d.
The flow rate regulators 304a to 304d adjust the opening degree of the BFG flow rate control valves 131a to 131d in the next combustion period so that the BFG flow rate becomes the target combustion pattern of the BFG flow rate. The flow rate controllers 304a to 304d derive the initial target value of the COG flow rate in the next combustion period based on the target combustion pattern of the C / B ratio and the target combustion pattern of the BFG flow rate. The flow rate regulators 304a to 304d adjust the opening degree of the COG flow rate control valves 133a to 133d in the next combustion period so that the COG flow rate reaches the initial target value. The flow rate controllers 304a to 304d have a PID controller. The opening degree of the COG flow rate control valves 133a to 133d other than the initial one in the next combustion period is adjusted by the PID controller. The PID controller feedback-controls the COG flow rate (opening of the COG flow rate control valves 133a to 133d) so that the dome temperature measured by the dome thermometers 135a to 135d becomes the target combustion pattern of the dome temperature.

The hot air furnace control calculation device 301 sets the target value of the temperature of the hot air discharged from the hot air furnaces 100a to 100d in the temperature controller 305. This target value is obtained based on the operation of the input device 312 by the operator. The temperature controller 305 instructs the opening controller 313a to 313d of the target opening degree. The opening degree adjusters 313a to 313d adjust the opening / closing operation of the blower butterfly valves 125a to 125d. For example, during the period in which the two hot air furnaces 100 are blowing air, the temperature controller 305 opens the opening degree of the blower butterfly valve 125 of the hot air furnace 100 that blows air in advance if the air blowing temperature is high. The opening degree of the blower butterfly valve 125 of the hot air furnace 100 that blows air afterwards is closed. On the contrary, if the blowing temperature is low, the temperature controller 305 closes the opening degree of the blowing butterfly valve 125 of the hot air furnace 100 that blows air in advance, and at the same time, closes the opening degree of the blowing butterfly valve 125 of the hot air furnace 100 that blows air later. Open the opening. In the hot air furnace 100 that blows air in advance, the hot air temperature is low because heat exchange is progressing. On the other hand, the hot air furnace 100 that blows air afterwards has a high hot air temperature because it stores sufficient heat. Therefore, the blowing temperature can be controlled by adjusting the opening degree (distribution of air volume) of these blowing butterfly valves 125. Further, the cold air butterfly valve 123 is gradually closed during the air blowing period to adjust the air blowing temperature.

The blower 306 blows cold air having an air volume set in the air flow rate adjuster 309. The setting of the blower flow rate controller 309 is changed at the blower factory.
Further, the hot air furnace control calculation device 301 causes the display device 303 to display the screen based on the above calculation results via the input / output device 302.

[Configuration of hot air furnace control calculation device 301]
An example of the processing performed by the hot air furnace control calculation device 301 will be described in detail below. In the following description, among the processes performed by the hot air furnace control calculation device 301, the configuration and operation of only the portion necessary for explaining the present embodiment will be described, and the configuration of the portion unnecessary for the description of the present embodiment will be described. And the detailed description of the operation will be omitted.
The hot air furnace control calculation device 301 can be realized by using, for example, a computer equipped with a CPU, ROM, RAM, and HDD. Further, the above-mentioned program is stored in the HDD, for example, and executed by the CPU.

FIG. 5 is a diagram showing an example of the functional configuration of the hot air furnace control calculation device 301. In FIG. 5, the hot air furnace control calculation device 301 has an input heat amount acquisition unit 501, a combustion pattern acquisition unit 502, and a target combustion pattern derivation unit 503.
<Overview>
FIG. 6 is a diagram illustrating an example of an outline of the functions of the hot air furnace control calculation device 301. An example of the outline of the function of the hot air furnace control calculation device 301 will be described with reference to FIG.
At the end of the blowing period, the input heat amount acquisition unit 501 derives the optimum value of the input heat amount for each furnace in the next combustion period. For example, when the ventilation period at the current time is the ventilation periods 403a and 403b, the next combustion period will be the combustion periods 402b and 402c, respectively. In the following description, the optimum value of the heat input for each furnace will be referred to as the optimum heat input, if necessary. In FIG. 6, the next optimum heat input Qin-1 is the optimum heat input in the next combustion period. Further, the previous optimum heat input Qin-0 is the optimum heat input derived by the input heat acquisition unit 501 immediately before the next optimum heat input Qin-1. For example, when the next optimum heat input Qin-1 is derived at the end of the ventilation period 403b (switching period 401e), the previous optimum heat input Qin-0 is derived at the end of the ventilation period 403a (switching period 401c). The optimum amount of heat input. The input heat amount acquisition unit 501 can derive the optimum input heat amount by using a known technique. For example, the description of Patent Documents 3 and 4 can be incorporated as a process of the input heat amount acquisition unit 501. As described above, the details of deriving the optimum heat input amount are described in Patent Documents 3 and 4, but in the present embodiment, the case where the optimum heat input amount is derived by using the technique described in Patent Document 3 is taken as an example. (However, refer to Patent Document 3 for details). Further, if the input heat amount acquisition unit 501 has acquired the calculated value of the input heat amount, it is not always necessary to derive the optimum input heat amount. For example, Patent Documents 1 and 2 describe methods for deriving the calculated value of the input heat amount without performing the optimization calculation.

The combustion pattern acquisition unit 502 derives the optimum value of the combustion pattern. As mentioned above, the combustion pattern is a general term for the flow rate of BFG, the C / B ratio, and the dome temperature. In the following description, the optimum value of the combustion pattern is referred to as an optimum combustion pattern, if necessary. Further, the flow rate of BFG is referred to as a BFG flow rate, if necessary. The optimum combustion pattern is derived at regular intervals. The constant cycle is, for example, the time (180 [min]) corresponding to one cycle.

In this embodiment, there are four hot air furnaces 100a to 100d. Therefore, the combustion pattern acquisition unit 502 individually derives the optimum combustion pattern for each of the hot air furnaces 100a to 100d. The optimum combustion pattern has an optimum value of the combustion pattern of the dome temperature, an optimum value of the combustion pattern of the BFG flow rate, and an optimum value of the combustion pattern of the C / B ratio. In the following description, the optimum value of the combustion pattern of the dome temperature, the optimum value of the optimum combustion pattern of the BFG flow rate, and the optimum value of the combustion pattern of the C / B ratio are defined as the optimum combustion pattern of the dome temperature and the optimum combustion of the BFG flow rate, respectively. It is called a pattern and an optimum combustion pattern of C / B ratio. The combustion pattern of the dome temperature shows the relationship between the dome temperature and time. The combustion pattern of the BFG flow rate shows the relationship between the BFG flow rate and time. The combustion pattern of the C / B ratio indicates the initial target value of the C / B ratio. FIG. 6 shows an optimum combustion pattern in one combustion period. Further, in FIG. 6, the combustion start time in one combustion period is referred to as “ts”, and the combustion end time is referred to as “te”. As for the combustion pattern of the dome temperature, the dome temperature is determined for each of a plurality of time zones of one combustion period. As for the combustion pattern of the BFG flow rate, the BFG flow rate is determined for each of a plurality of time zones of one combustion period, similarly to the combustion pattern of the dome temperature. In the example shown in FIG. 6, in the combustion pattern of the dome temperature / BFG flow rate, the dome temperature / BFG flow rate is determined for each of the three time zones in which one combustion period is divided into three. On the other hand, as the combustion pattern of the C / B ratio, only the initial target value of the C / B ratio in one combustion period is determined.

The combustion pattern acquisition unit 502 can derive an optimum combustion pattern by using a known technique. For example, the description of Patent Document 5 can be incorporated as the processing of the combustion pattern acquisition unit 502. In the present embodiment, a case where the optimum combustion pattern is derived by using the technique described in Patent Document 5 will be described as an example (however, refer to Patent Document 5 for details). Further, the combustion pattern acquisition unit 502 does not necessarily have to derive the optimum combustion pattern as long as the calculated value of the combustion pattern is acquired. A method for deriving a calculated value of a combustion pattern without performing an optimization calculation is described in, for example, Patent Document 6. In FIG. 6, () is shown in the optimum combustion pattern of the C / B ratio. In the present embodiment, the combustion pattern acquisition unit 502 acquires the optimum combustion pattern of the C / B ratio. Indicates that it does not have to be.

The target combustion pattern derivation unit 503 is activated at a timing within the next switching period of the ventilation period, after the next optimum input heat amount Qin-1 is derived by the input heat amount acquisition unit 501. For example, when the blowing period at the current time is the blowing period 403a and 403b, the next switching period is the switching period 401c and 401e, respectively. The target combustion pattern derivation unit 503 determines the next combustion period based on the next optimum input heat amount Qin-1 and the previous optimum input heat amount Qin-0, the latest optimum combustion pattern, and the target combustion pattern in the previous combustion period. Derivation of the target combustion pattern in. The target combustion pattern includes a target combustion pattern of the dome temperature, a target combustion pattern of the BFG flow rate, and a target combustion pattern of the C / B ratio. The target combustion pattern of the C / B ratio is the initial target value of the C / B ratio in the next combustion period of each hot air furnace 100a to 100d. In the graph at the bottom of the column of the next target combustion pattern in FIG. 6, the C / B ratio that changes due to the feedback control by the PID controller described above from the initial target value of the C / B ratio is calculated as the C / B ratio. Shown with the initial target value.

In the following description, the target combustion pattern in the previous combustion period will be referred to as the previous target combustion pattern, if necessary. Further, the target combustion pattern in the next combustion period is referred to as the next target combustion pattern, if necessary. For example, when the target combustion pattern derivation unit 503 derives the next target combustion pattern at the end of the ventilation period 403b, the previous target combustion pattern is the next target combustion pattern derived by the target combustion pattern derivation unit 503 at the end of the ventilation period 403a. Become a pattern.
As described above, in the present embodiment, the target combustion pattern deriving unit 503 derives the next target combustion pattern by using not only the input heat amount but also the optimum combustion pattern and the previous target combustion pattern. Therefore, the flow rates of BFG and COG are controlled so as to suppress the decrease in the thermal efficiency of the hot air furnaces 100a to 100d (= the amount of heat of the hot air blown from each hot air furnace 100a to 100d / the amount of heat input to each hot air furnace 100a to 100d). can do.

<Details>
A detailed example of the function of the hot air furnace control calculation device 301 will be described below.
(Chemical input acquisition unit 501)
As described above, in the present embodiment, the case where the input heat amount acquisition unit 501 derives the optimum input heat amount by using the technique described in Patent Document 3 will be described as an example.
The input heat amount acquisition unit 501 inputs, for example, the following information as information based on the operation of the input device 312 by the operator of the hot air furnace.
-Operating target values (target blowing temperature BT _ref (time), target blowing flow rate BV _ref (time), target blowing time BTime _ref ) when changing the operation of the hot air furnaces 100a to 100d to the state according to the request from the blast furnace. (Time)). In this embodiment, the target ventilation time BTime _ref (time) is a fixed value.
・ Equipment load (thermal efficiency η (i, n + j) by furnace / cycle, heat input Qin (i, n + j) by furnace / cycle, heat storage Q _bf (i, n + j) by furnace / cycle, furnace The initial value of the candidate for the heat storage sharing ratio α (i, n + j) for each cycle.

・ Target silicate brick minimum temperature T _{si, ref} (i, n + j) candidate initial value by furnace ・ Coefficient of linear time series model representing process model of hot air furnace a _{0 ・ x} (i), b _{0・ X} (i), c _{0 ・ x} (i), a _{1 ・ x} (i), b _{1 ・ x} (i), c _{1 ・ x} (i)
-Weight coefficients w ₁ (i) and w ₂ (i) of the objective function J ₁ (i)

-Target number of cycles q (q is a positive integer) that determines the optimization time range 802 of the target silica brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle.
Here, the number of cycles q is set so that the number of cycles q corresponds to a time longer than the time constant of the hot air furnaces 100a to 100d. For example, it is assumed that the number of cycles corresponding to the cycle to which the current time belongs is n, and the time constant of the hot air furnaces 100a to 100d is 3 days. In this case, the number of cycles q is set so that the number of cycles corresponding to the cycle three days or more ahead of the cycle to which the current time belongs is n + q (see FIG. 8).

-The number of cycles s (s is a positive integer) that determines the control section 902 (see FIG. 9) to be derived from the heat input Q _{in, p} (i, t) for each furnace and each cycle after the present time.
Here, the number of cycles s determines the last cycle of the control section 902, and the number of cycles n + s is a value lower than the time constant and the number of cycles n + q of the hot air furnaces 100a to 100d (FIGS. 8 and 9). reference).
-The number of cycles d, m (d, m are positive integers) that determine the prediction interval 901 (see FIG. 9) of the predicted minimum temperature of silica stone brick T _{si, p} (i, t) for each furnace and cycle. <M)
Here, the number of cycles d (d is a positive integer) determines the first cycle of the prediction interval 901 (see FIG. 9). Further, the number of cycles d is a value larger than the number of cycles s (more than or equal to the number of cycles s) (see FIG. 9).
The number of cycles m determines the final cycle of the prediction interval 901 (see FIG. 9). The number of cycles m is a value lower than the time constant and the number of cycles q of the hot air furnaces 100a to 100d (see FIGS. 8 and 9).
As described above, the prediction interval 901 and the control interval 902 are periods below the time constant and the optimization time range 802 of the hot air furnaces 100a to 100d. Also, the last cycle of the control interval 902 is (in time) earlier than the first cycle of the prediction interval 901.

As the prediction interval 901, the predicted value T _{si, p} (i, t) of the minimum silica stone temperature for each furnace and cycle is the target value (the target minimum temperature for silica stone brick for each furnace and cycle T _{si, ref} (i). , N)) is appropriately set by the operator in a section that closely follows). Even if the operating conditions such as the blast flow rate BV and the blast temperature BT are changed, the heat storage amount of the hot blast furnaces 100a to 100d does not immediately reflect the change in the operating conditions. Therefore, for example, the number of cycles corresponding to the time after the heat storage amount of the hot air furnaces 100a to 100d begins to reflect the change in the operating conditions can be set as the number of cycles d. On the other hand, as the number of cycles m, for example, the number of cycles corresponding to the time 8 hours to 1 day ahead can be set.

-Known data (physical constants / equipment constants) of equipment (clay brick 109, high alumina brick 110, silica stone brick 111, etc.) and gas (combustion gas, auxiliary air, etc.) constituting the hot air furnace 100.
In addition to this, the input heat amount acquisition unit 501 also inputs information set in advance by the operator in the calculation described later.

Here, the subscript ref indicates that it is a target value, and the subscript p indicates that it is a future value.
Further, the values of (i, n + j) and i in (i) indicate that the values may differ depending on the hot air furnaces 100a to 100d. In the present embodiment, since there are four hot air furnaces 100a to 100d, i is 1 to 4. Further, n, j, t of (i, n + j) and (i, t) indicate that the values may differ depending on the cycle. n represents the number of cycles of the cycle to which the current time belongs, and n + j represents the number of cycles of the cycle j ahead of the cycle to which the current time belongs. t represents the number of cycles ahead of the cycle to which the current time belongs.
Further, the time of (time) indicates that the value may differ depending on the time (for example, the time with the minute (min) as the minimum unit).

In the present embodiment, T _{si, ref} (i, n), T _{si, ref} (i, n + 1) are used as initial values of the target silica brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle. ), ..., T _{si, ref} (i, n + q) are set.
Further, the target blast temperature BT _ref (time) and the target blast flow rate BV _ref (time) are set in the time corresponding to the number of cycles n to n + q (optimization time range 802).

In addition, as the target silica stone brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle, T _{si, ref} (i, n), T _{si, ref} (i, n + 1), ..., T _{si , Ref} (i, n + q) is derived.
In addition, as the predicted values T _{si, p} (i, t) of the minimum temperature of silica stone bricks for each furnace and cycle, T _{si, p} (i, n + d + g), T _{si, p} (i, n + d + 1 + g), ... T _{si, p} (i, n + m + g) is derived. Here, g is an integer from 0 (zero) to q-m. That is, T _{si, p} (i, n + d) to T _{si, p} (i, n + m), T _{si, p} as the predicted values T _{si, p} (i, t) of the minimum temperature of silica stone brick for each furnace and cycle. (I, n + d + 1) to T _{si, p} (i, n + m + 1), T _{si, p} (i, n + d + 2) to T _{si, p} (i, n + m + 2), ..., T _{si, p} (i, n + d + q-m) ) To T _{si, p} (i, n + m + q−m) are derived in this order. Of the derived predicted values T _{si, p} (i, t) of the minimum temperature of silica stone bricks for each furnace and cycle, the latest values are adopted for the overlapping cycle values.

In addition, Q _{in, p} (i, n + g), Q _{in, p} (i, n + 1 + g), ..., Q _{in are the} heat input Q _{in, p} (i, t) for each furnace and cycle after the present time. _{, P} (i, n + s + g) is derived. That is, Q _{in, p} (i, n) to Q _{in, p} (i, n + s), Q _{in, p} (i) are the heat input Q _{in, p} (i, t) for each furnace and cycle after the present time. , N + 1) to Q _{in, p} (i, n + s + 1), ..., Q _{in, p} (i, n + g) to Q _{in, p} (i, n + s + g) are derived in this order. Of the derived heat input Q _{in, p} (i, t) for each furnace and each cycle since the present time, the latest value is adopted for the value of the overlapping cycle.
Further, the input heat quantity acquisition unit 501 inputs the information indicating the above-mentioned operation results.

The outline of an example of the processing performed by the input heat amount acquisition unit 501 will be described below.
The input heat amount acquisition unit 501 executes a heat storage amount target trajectory derivation program to derive the target silica brick minimum temperature T _{si, ref} (i, n + j) for each furnace and each cycle. Target silica stone brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle is from the cycle to which the current time belongs until the cycle corresponding to the time longer than the time constant of the hot air furnaces 100a to 100d elapses. Derived in each cycle. For example, the target silica stone brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle is set in each cycle from the cycle to which the current time belongs to the cycle corresponding to 3 days or more ahead of the day to which the current time belongs. Derived. Here, the cycle to which the current time belongs is defined as a cycle having n cycles. A cycle corresponding to a time longer than the time constant of the hot air furnaces 100a to 100d is defined as a cycle having n + q cycles. j is represented by the following equation (1).
j = 0,1, ..., q ... (1)

Next, the hot air furnace control calculation device 301 executes the input heat amount derivation program, and sets the input heat amount Q _{in, p} (i, t) to each hot air furnace 100a to 100d after the present time for each hot air furnace 100a to 100d. Calculate individually. The amount of heat input Q _{in, p} (i, t) to each hot air furnace 100a to 100d after the present time is the predicted value T _{si, p} (i, t) of the minimum temperature of silica brick for each furnace and each cycle. -Target for each cycle Silica brick is calculated to follow the minimum temperature T _{si, ref} (i, n + j).
FIG. 7 is a diagram showing an example of a detailed functional configuration of the input heat amount acquisition unit 501. FIG. 8 is a diagram conceptually showing an example of the target silica brick minimum temperature T _{si, ref} (i, n + j) for each furnace and each cycle and the operation target value (operation condition).
As shown in FIG. 7, the input heat amount acquisition unit 501 includes a heat storage amount target trajectory optimization unit 701, a first process state prediction unit 702, an optimum tracking control unit 703, and a second process state prediction unit 704. Have.

((Heat storage amount target trajectory optimization unit 701, first process state prediction unit 702))
The heat storage amount target trajectory optimization unit 701 and the first process state prediction unit 702 are the parts that execute the above-mentioned heat storage amount target trajectory derivation program. As described above, by executing the heat storage target orbit derivation program, the target silica brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle can be set to the optimization time range 802 (j = 0, 1). , ..., q). The optimization time range 802 is the time from the cycle to which the current time belongs (cycle number n) to the elapse of the cycle (cycle number n + q) corresponding to the time longer than the time constant of the hot air furnaces 100a to 100d. Thus for a long period of time, filtrated cycle another goal silica brick lowest temperature _{T si, ref (i, n} + j) is to derive, Alternative filtrated cycle targets silica brick lowest temperature T _{si, ref} This is to make (i, n + j) reflect the state until the temperature of each part of the hot air furnaces 100a to 100d reaches the equilibrium state.
An example of the functions of the heat storage amount target trajectory optimization unit 701 and the first process state prediction unit 702 will be described below.

The heat storage target trajectory optimization unit 701 fluctuates the operation target value 801 from the cycle to which the current time belongs (number of cycles n) to the cycle to which the time to which the optimization time range 802 elapses (number of cycles n + q) belongs. Determine whether or not to do so. The operation target value 801 indicates an operation condition. The operation target value 801 is, for example, a target blast temperature BT _ref (time), a target blast flow rate BV _ref (time), or a target blast heat amount obtained from these.
As a result of this determination, when the operation target value 801 fluctuates, the following processing is executed. In the example shown in FIG. 8, the operation target value 801 fluctuates three times within the optimization time range 802. In addition, this determination is performed every 1 [min], for example.

When it is determined that the operation target value 801 is fluctuating as described above, the heat storage amount target trajectory optimization unit 701 is a candidate for the target silica brick minimum temperature T _{si, ref} (i, n + j) for each furnace and each cycle. Is output to the first process state prediction unit 702. The value input to the input / output device 302 is used as the initial value of the candidate for the target silica stone brick minimum temperature T _{si, ref} (i, n + j) for each furnace and each cycle.

FIG. 9 shows the target silica stone brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle, and the predicted values T _{si, p} (i, t) for the silica stone brick minimum temperature for each furnace and cycle. It is a figure which conceptually shows an example of the operation target value (operation condition), and the input heat amount Q _{in, p} (i, t) for each furnace and each cycle.
The first process state prediction unit 702 derives the predicted value of the process state of each hot air furnace 100a to 100d by using the process model. The process model has a plurality of calculation formulas. The plurality of calculation formulas are formulas for individually calculating the process state of the hot air furnaces 100a to 100d by using the input heat amount Q _in for each furnace and each cycle for the hot air furnaces 100a to 100d. In the present embodiment, the predicted values of the process states of the hot blast furnaces 100a to 100d are the heat input Q _{in, p} (i, t) for each furnace and each cycle since the present time, and the minimum silicate brick for each furnace and each cycle. Includes the predicted temperature T _{si, p} (i, t) and the predicted blast temperature BT _p (i, t) for each furnace and cycle. Here, t represents the number of cycles in the prediction interval 901 or the control interval 902, and is represented by the following equations (2a) and (2b).
Prediction interval; t = n + d + g, n + d + 1 + g, ..., n + m + g ... (2a)
Control interval; t = n + g, n + 1 + g, ..., n + s + g ... (2b)

As described above, n is the number of cycles to which the current time belongs. d represents the number of cycles corresponding to the first cycle of the prediction interval 901. m represents the number of cycles corresponding to the last cycle of the prediction interval 901. g is an integer from 0 (zero) to q-m. That is, the prediction interval 901 is an interval in the range of the number of cycles md.
As described above, the prediction interval 901 is the interval in the range of the number of cycles md shifted backward by one cycle until the number of cycles corresponding to the last cycle becomes n + q−m (FIG. 9). (See the white arrow line next to the prediction interval 901). Further, the control section 902 is a section in which the range of the number of cycles s is shifted backward by one cycle until the number of cycles corresponding to the last cycle becomes n + s + q−m (in the control section 902 of FIG. 9). See the white arrow line next to it).

In the present embodiment, the first process state prediction unit 702 uses a linear time series model as the process model. The linear time series model is one of the statistical analysis models that calculates the predicted value of the process state for each cycle.
Specifically, the predicted values T _{si, p} (i, t) of the minimum temperature of silica stone brick for each furnace and each cycle can be obtained by using the following equation (3).

In the equation (3), the coefficients a _{0 · x} (i), b _{0 · x} (i), and c _{0 · x} (i) are the coefficients input based on the operation of the input device 312. For example, as these coefficients, the coefficient when the form of Eq. (3) best matches the past operation results of the hot air furnaces 100a to 100d is separately obtained. The coefficients are input as coefficients a _{0 · x} (i), b _{0 · x} (i), c _{0 · x} (i) based on the operation of the input device 312. As a method for matching the shape of Eq. (3) with the past operation results of the hot air furnaces 100a to 100d, a method such as the least squares method is used.
ΔT _{si, p} (i, n + j + 1) is expressed by the following equation (4).
ΔT _{si, p} (i, n + j + 1) = T _{si, p} (i, n + j + 1) -T _{si, p} (i, n + j) ... (4)

ΔT _si (i, n + j−x) is expressed by the following equation (5).
ΔT _si (i, n + j-x) = T _si (i, n + j-x) -T _si (i, n + j-x-1) ... (5)
The first process state prediction unit 702 sets the lower end temperature of the silica stone brick input as the operation record for the past value among the minimum temperature T _si (i, n + j−x) of the silica stone brick for each furnace and each cycle. To do. On the other hand, for future values, the predicted values T _{si, p} (i, t) of the minimum temperature of silica stone bricks for each furnace and each cycle obtained by Eq. (4) are set.

ΔQ _in (i, n + j + 1-x) is expressed by the following equation (6).
ΔQ _in (i, n + j + 1-x) = Q _in (i, n + j + 1-x) -Q _in (i, n + j-x) ... (6)
The first process state prediction unit 702 sets the past values of the input heat amount Q _{in, p} (i, t) for each furnace and each cycle in the past values of Q _in (i, n + j + 1-x). Set. In addition, the first process state prediction unit 702 calculates the future value as the heat input Q _{in, p} (i, t) for each furnace and cycle after the present time, which has already been derived at the present time. Candidates for the amount of heat input Q _{in, p} (i, n + g) to Q _{in, p} (i, n + s + g) for each furnace and each cycle after the present time in the target control section 902 are set.

ΔQ _out (i, n + j + 1-x) is expressed by the following equation (7).
ΔQ _out (i, n + j + 1-x) = Q _out (i, n + j + 1-x) -Q _out (i, n + j-x) ... (7)
Q _out is the amount of heat blown [J]. The first process state prediction unit 702 obtains the past values of the blown heat amount Q _out (i, n + j + 1-x) for each furnace and cycle from the blown temperature and blown flow rate input as the operation results. Set the amount of heat blown for each furnace and cycle. On the other hand, for future values, the amount of heat blown for each furnace and cycle obtained from the operation target values (target blown temperature BT _ref (time), target blown flow rate BV _ref (time)) is set.
As described above, the first process state prediction unit 702 sets the predicted values T _{si, p} (i, t) of the minimum temperature of silica stone bricks for each furnace and each cycle at least i = 1 to 4, t =. Each of n to n + m + g is derived. Then, the first process state prediction unit 702 has i = 1 to 4, t = n + d + g to n + m + g among the derived predicted values T _{si, p} (i, t) of the minimum temperature of silica stone bricks for each furnace and cycle. Is adopted as the predicted value T _{si, p} (i, t) of the minimum temperature of silica stone brick for each furnace and each cycle in the predicted section 901.

Further, the predicted value BT _p (i, t) of the blast temperature for each furnace and each cycle can be obtained by using the following equation (8).

In the equation (8), the coefficients a _{1 · x} (i), b _{1 · x} (i), and c _{1 · x} (i) are the coefficients input based on the operation of the input device 312. These coefficients a _{1 · x} (i), b _{1 · x} (i), c _{1 · x} (i) are also the coefficients a _{0 · x} (i), b _{0 · x} (i), c _{0 · x} ( It is obtained in advance in the same manner as in i).
ΔBT _p (i, n + j + 1) is expressed by the following equation (9).
ΔBT _p (i, n + j + 1) = BT _p (i, n + j + 1) -BT _p (i, n + j) ... (9)

ΔBT (i, n + j−x) is represented by the following equation (10).
ΔBT (i, n + j-x) = BT (i, n + j-x) -BT (i, n + j-x-1) ... (10)
The first process state prediction unit 702 sets the blast temperature input as the operation record for the past value among the blast temperature BT (i, n + j-x) for each furnace and each cycle. On the other hand, for future values, the predicted value BT _p (i, t) of the blast temperature for each furnace and each cycle obtained by Eq. (8) is set.
ΔQ _in (i, n + j + 1-x) and ΔQ _out (i, n + j + 1-x) are represented by the above-mentioned equations (6) and (7), respectively.

As described above, the first process state prediction unit 702 predicts the minimum temperature of the silicate brick for each furnace and cycle in the prediction interval 901 T _{si, p} (i, n + d + g) to T _{si, p} (i, n + m + g) and the predicted values BT _p (i, n + d + g) to BT _p (i, n + m + g) of the blast temperature for each furnace and each cycle in the prediction interval 901 are derived. Then, the first process state prediction unit 702 sets the value of the evaluation value of the furnace-specific objective function J ₁ (i) of the following equation (11) to the constraint conditions of the following equations (12) and (13). Using the optimization method, how much the candidate values of the input heat amount Q _{in, p} (i, t) for each furnace and each cycle after the present time should be changed in order to minimize within the range to be satisfied. to decide. The logic of this determination can be realized by known methods such as GA, hill climbing, and linear programming. The amount of change in the candidates for the input heat amount Q _{in, p} (i, t) for each furnace and each cycle after the present time in the control section 902 is determined according to this logic. Based on this change amount, the first process state prediction unit 702 determines that the value of the evaluation value of the furnace-specific objective function J ₁ (i) in Eq. (11) is the minimum, and the furnace after the present time in the control section 902. The calculation of the above-mentioned equations (3) to (13) is repeated by changing the candidate values of the input heat amount Q _{in, p} (i, t) for each cycle.

In equation (11), T _{si, err} (i, t) is represented by the following equation (14), and ΔQ _in (i, t) is represented by the following equation (15).
T _{si, err} (i, t) = T _{si, ref} (i, t) -T _{si, p} (i, t) ... (14)
ΔQ _in (i, t) = Q _in (i, t) −Q _in (i, t-1) ・ ・ ・ (15)
Further, in the equations (12) and (13), Th ₁ (i) and Th ₂ (i) are threshold values, which are set in advance. Further, BT _{p, min} (i, t) indicates that it is the lowest value of the predicted value BT _p (i, t) of the blast temperature for each furnace and each cycle. Further, BT _ref (i, t) is the target blast temperature. As described above, in the present embodiment, the target blowing temperature BT _ref (time) is dependent on the time without depending on the furnace i time, the target blowing temperature time time corresponding to the cycle t BT _ref (time ) Is adopted as BT _ref (i, t).
The first term on the right side of Eq. (11) is the predicted value T _{si, p} (i, t) of the minimum temperature of silica stone brick for each furnace and cycle in the prediction interval 901, and the minimum target silica brick for each furnace and cycle. This is an objective function whose purpose is to follow the temperature T _{si, ref} (i, n + j) well. The second term on the right side of the equation (11) is intended to reduce the fluctuation of the input heat amount Q _in (i, t) for each furnace and each cycle in the same hot blast furnace 100 in adjacent cycles. It is a function. The furnace-specific objective functions shown in Eq. (11) are represented by the weighted linear sum of these objective functions.

The first process state prediction unit 702 sets the predicted value when the value of the evaluation value of the objective function J ₁ (i) for each furnace of the equation (11) is minimized for the process state of each hot air furnace 100a to 100d. As a predicted value, it is output (replied) to the heat storage amount target trajectory optimization unit 701. This predicted value is the predicted value of the minimum temperature of silicate bricks by furnace and cycle T _{si, p} (i, n + d + g) to T _{si, p} (i, n + m + g) and the predicted value of the blast temperature by furnace and cycle. BT _p (i, n + d + g) to BT _p (i, n + m + g) and the amount of heat input Q _{in, p} (i, n) to Q _in (i, n + s + g) for each furnace and each cycle after the present time are included.

Derivation of the predicted value of the process state of each of the hot blast furnaces 100a to 100d as described above is performed sequentially by shifting the prediction section 901 and the control section 902 backward by one cycle. For example, the first process state prediction unit 702 sets a cycle interval of the number of cycles n + d to n + m as the prediction interval 901, and sets a cycle interval of the number of cycles n to n + s as the control interval 902. Predicted values of process states of each hot air furnace 100a to 100d are derived. Next, the first process state prediction unit 702 sets a cycle section of the number of cycles n + d + 1 to n + m + 1 as the prediction interval 901, and sets a cycle section of the number of cycles n + 1 to n + s + 1 as the control section 902. Then, the predicted value of the process state of each hot air furnace 100a to 100d is derived.

Then, when the predicted value of the process state when the last cycle of the prediction interval 901 becomes a cycle of the number of cycles n + q is derived, the derivation of the predicted value of the process state is completed. By doing so, the predicted value of the process state in each cycle of the number of cycles n to n + q−m is derived. Here, among the predicted values of the process states derived in the same cycle, the latest predicted values of the process state are adopted.

When the heat storage amount target trajectory optimization unit 701 inputs the predicted value of the process state of each hot air furnace 100a to 100d from the first process state prediction unit 702, the objective function J ₂ for each furnace of the following equation (16) (16) In order to minimize the value of the evaluation value of i) within the range satisfying the constraint conditions of the following equations (17) and (18), the target siliceous brick minimum temperature T _{si, ref} (i) for each furnace and each cycle. , N + j), how much the candidate values should be changed is determined by using the optimization method. The logic of this determination can be realized by known methods such as GA, hill climbing, and linear programming. The amount of change in the candidate for the target silica stone brick minimum temperature T _{si, ref} (i, n + j) for each furnace and cycle is determined according to this logic. Based on this amount of change, the target silica brick minimum temperature T _{si, ref for each} furnace and cycle until the value of the evaluation value of the objective function J ₂ (i) for each furnace in Eq. (16) can be regarded as the minimum. By changing the candidate values of i, n + j), the above-mentioned calculations of equations (3) to (18) are repeated.

In the equations (17) and (18), Th ₃ (i) and Th ₄ (i) are threshold values, which are set in advance.
The heat storage target orbit optimization unit 701 describes the “target for each furnace / cycle in the optimization time range 802” when the value of the evaluation value of the objective function J ₂ (i) for each furnace in Eq. (16) becomes the minimum. The minimum temperature of silicate brick T _{si, ref} (i, n + j) (candidate value) ”is stored.

((Optimal tracking control unit 703, second process state prediction unit 704))
The optimum tracking control unit 703 and the second process state prediction unit 704 are parts that execute the above-mentioned input heat amount derivation program. As described above, the heat storage amount target orbit optimization unit 701 derives the target silica brick minimum temperature T _{si, ref} (i, n + j) for each furnace and each cycle in the optimization time range 802. Then, the optimum follow-up control unit 703 predicts the input heat amounts Q _{in, p} (i, n + g) to Q _{in, p} (i, n + s + g) for each furnace and each cycle in the control section 902 after the present time in the second process state. Output to unit 704. Then, the second process state prediction unit 704 derives the predicted value T _{si, p} (i, n + j) of the minimum temperature of the silica stone brick for each furnace and each cycle in the prediction interval 901. As described above, the prediction interval 901 is a period that is ahead of the cycle to which the current time belongs (cycle number n) by the number of cycles d to m. The time corresponding to the number of cycles n + m is less than the time constant of the hot air furnaces 100a to 100d. In this way, the time corresponding to the number of cycles n + m is set to be less than the time constant of the hot air furnaces 100a to 100d, which is the predicted value T _{si, p} (i, n + j) of the minimum temperature of silica stone bricks for each furnace and each cycle. ) Is derived too far ahead, and if there is a change in operation, many of the derived values may be wasted.

Then, in the optimum tracking control unit 703, the predicted value T _{si, p} (i, n + j) of the minimum temperature of silica stone brick for each furnace / cycle is the target minimum temperature of silica stone brick T _{si, ref} (i) for each furnace / cycle. , N + j), candidates for the input heat amounts Q _{in, p} (i, n + g) to Q _{in, p} (i, n + s + g) for each furnace and each cycle after the present time in the control section 902 are derived. The control section 902 is a period in the range of the number of cycles s. The optimum tracking control unit 703 and the second process state prediction unit 704 perform the above processing in the control section 902 from the present time onward by the input heat amount Q _{in, p} (i, n + g) to Q _{in, p} for each furnace and cycle. Repeat until the optimum solution of (i, n + s + g) is obtained.
An example of the functions of the optimum tracking control unit 703 and the second process state prediction unit 704 will be described below.

The optimum tracking control unit 703 determines for each of the hot air furnaces 100a to 100d whether or not the predetermined time within the switching period before the start of the combustion period of each cycle has been reached.
As a result of this determination, in any of the hot air furnaces 100a to 100d, when the predetermined time within the switching periods 401a, 401c, 401e before the combustion periods 402a, 402b, 402c of each cycle starts, the following processing is executed. Will be done.

The optimum tracking control unit 703 predicts the candidates of the input heat amounts Q _{in, p} (i, n + g) to Q _{in, p} (i, n + s + g) for each furnace and each cycle in the control section 902 after the present time as the second process state prediction. Output to unit 704. At first, the optimum tracking control unit 703 starts from the cycle (number of cycles n−s-1) s-1 before the cycle to which the current time belongs (number of cycles n) to 1 from the cycle to which the current time belongs. The value of the input heat amount Q _{in, p} (i, t) for each furnace and each cycle up to the previous cycle (number of cycles n-1) Q _{in, p} (i, n−s-1) to Q _{in, p} (I, n-1) is output to the second process state prediction unit 704.

The second process state prediction unit 704 executes the hot air furnace simulator. The hot blast furnace simulator is constructed using a hot blast furnace model that faithfully reproduces the heat exchange performed in the hot blast furnace 100 by combustion and ventilation by utilizing thermophysics. The hot air furnace simulator is a process model as well as a linear time series model. The process model has a plurality of calculation formulas. The plurality of calculation formulas are formulas for individually calculating the process state of the hot air furnaces 100a to 100d by using the input heat amount Q _in for each furnace and each cycle for the hot air furnaces 100a to 100d. However, the hot blast furnace simulator calculates the predicted value of the process state at time intervals less than one cycle, and can calculate the predicted value of the process state more strictly than the linear time series model. Since the hot air furnace model is described in Patent Document 3, detailed description thereof will be omitted here.

The second process state prediction unit 704 realizes the functions shown below by using the model equations of the following equations (19) to (21). Equation (19) is a model equation representing the heat balance of gas. Equation (20) is a model equation representing the heat balance of the heat storage brick. Equation (21) is a model equation representing the heat balance of the furnace wall brick.

The meanings of the symbols in the equations (19) to (21) are as follows.
ρ: Density [kg / m ³ ]
C _p : Specific heat [J / kg · K]
S: Cross-sectional area [m ² ] (the (net) cut area of the brick obtained by subtracting the sum of the cross-sectional areas of the passing ports from the cross-sectional area of the above-mentioned cylinder cut along its axis)
v: Flow velocity [m / s]
T: Temperature [K]
h: Heat transfer coefficient [W / m ² · K]
A: Contact area [m ² ]
L: Height [m] (set the furnace bottom to 0)
ε: Emissivity [-]
z: Position in the height direction [m]
t: time [s]
G: Gas CH: Heat storage brick W: Furnace wall brick Wb: Brick constituting the furnace wall brick Wb-1, Wb + 1: Brick next to the brick specified by Wb δ: Stefan-Boltzmann constant

FIG. 10 is a diagram showing an example of a detailed functional configuration of the second process state prediction unit 704.
The second process state prediction unit 704 is roughly divided into a combustion simulation unit 1001 and a blast simulation unit 1002.
((Combustion simulation unit 1001))
The combustion simulation unit 1001 is for simulating the state of each hot air furnace 100a to 100b during the combustion period.
The combustion simulation unit 1001 includes a gas capacity calculation unit 1001a used and a model formula calculation unit 1001b.

<Gas capacity calculation unit 1001a>
The gas capacity calculation unit 1001a used has the heat input Q _{in, p} (i, t) for each furnace and cycle since the present time, which has already been derived at the present time, and the current time in the control section 902 which is the calculation target at the present time. Subsequent candidates for the input heat amount Q _{in, p} (i, t) for each furnace and each cycle are input. Here, the heat input Q _{in, p} (i, t) for each furnace and each cycle after the present time is derived by shifting the control section 902 backward by one cycle. Therefore, assuming that the number of cycles indicating the control section 902 that has already been calculated is n to n + s + v, the control section 902 currently being calculated is n + v + 1 to n + s + v + 1.

Further, the gas capacity calculation unit 1001a inputs the usage ratio [−] of each gas used in BFG, COG, and LDG. The usage ratio of the gas used is assumed to change during the combustion period, and one combustion period can be individually set for each of a plurality of divided time zones.
Further, the gas capacity calculation unit 1001a input the gas calorie (gas composition unit calorie) [J / Nm ³ ] of each gas used for BFG, COG, LDG, and air.
The gas capacity calculation unit 1001a calculates the capacity [Nm ³ ] of each gas used in BFG, COG, LDG, and air based on the above input information, and outputs the capacity [Nm ³ ] to the model formula calculation unit 1001b.

<Model formula calculation unit 1001b>
The model formula calculation unit 1001b inputs the capacities of each gas of BFG, COG, LDG, and air from the gas capacity calculation unit 1001a used.
The model formula calculation unit 1001b inputs the gas combustion temperature _TG [° C.], the density ρ _G [kg / m ³ ], and the specific heat C _{p, G} [J / kg · K]. Here, the subscript G represents gas. Here, the gas combustion temperature _TG refers to the temperature at which the gas is burned.
Then, the model formula calculation unit 1001b uses the input information and uses the above-mentioned model formulas (formulas (19) to (21)) from the start of combustion to the end of combustion (one combustion period). , The heat balance in the hot air furnaces 100a to 100d is calculated, and the following values at the end of combustion are output.
・ Temperature of heat storage bricks by furnace and cycle T _CH (i, t)
・ Temperature of furnace wall bricks by furnace and cycle T _Wb (i, t)
・ Exhaust gas temperature by furnace and cycle T _ex (i, t)
・ Combustion efficiency η (i, t) by furnace and cycle

The gas volume V _G is reflected in " _SG x v _G " on the left side of the equation (19). Further, filtrated cycle-specific exhaust gas temperature T _ex (i, t) is the amount of heat which has not been heated in the combustion period to be calculated, and the gas volume V _G, intended to be calculated by using the components of the gas is there.
The above processing of the gas capacity calculation unit 1001a and the model formula calculation unit 1001b is repeated every cycle.

((Simulation unit 1002 when blowing air))
The blast simulation unit 1002 is for simulating the state of each hot blast furnace 100a to 100b during the blast period.
The blast simulation unit 1002 includes an operation content instruction unit 1002a, a model formula calculation unit 1002b, and a blast flow rate / temperature determination unit 1002c.

<Operation content indicator 1002a>
From the model formula calculation unit 1001b, the operation content instruction unit 1002a indicates the temperature T _CH (i, t) of the heat storage brick for each furnace and cycle and the temperature T _Wb (i, t) for the brick wall for each furnace and cycle. The calculation starts every time you enter. That is, the operation content instruction unit 1002a starts the calculation in the combustion simulation unit 1001 every time the calculation at the end of combustion in the combustion period is completed. Here, it is assumed that the calculation is repeated so that the calculation result every 3 seconds can be obtained.

The operation content indicating unit 1002a uses the "passing air flow rate BHS (i, time + 3) for each furnace and time and the mixed cooling flow rate Air (i) for each furnace and time, which are determined by the air flow rate / temperature determination unit 1002c described later. , Time + 3) ”is the“ passing air flow rate BHS (i, time) by furnace / hour and the mixing / cooling flow rate Air (i, time) by furnace / hour ”for the time to be calculated. Here, time represents time (time), and time + 3 represents 3 seconds after time time.
Then, the operation content instruction unit 1002a outputs the passing air flow rate BHS (i, time) for each furnace and time to the model formula calculation unit 1002b, and the mixed cooling flow rate Air (i, time) for each furnace and time. Is output to the air flow rate / temperature determination unit 1002c. Here, the passing air flow rate is the flow rate of cold air that has entered the mixing / cooling chamber 103 through the duct 114, the heat storage chamber 101, and the combustion chamber 102 shown in FIG. The mixing / cooling flow rate is the flow rate of cold air that has entered the mixing / cooling chamber 103 through the duct 118 shown in FIG. The sum of the passing air flow rate and the mixing / cooling flow rate is the air flow rate BV (i, time).
In the first calculation, the air flow rate / temperature determination unit 1002c, which will be described later, states that "passing air flow rate BHS (i, time + 3) by furnace and time and air-cooling flow rate Air (i, time + 3) by furnace / time). "Has not been decided. Therefore, the operation content indicating unit 1002a adopts the initial values of the passing air flow rate BHS (i, time) for each furnace and time and the mixed cooling flow rate Air (i, time) for each furnace and time. As these initial values, the values input to the input / output device 302 are used.

<Model formula calculation unit 1002b>
From the model formula calculation unit 1001b, the model formula calculation unit 1002b determines the temperature T _CH (i, t) of the heat storage bricks by furnace and cycle and the temperature T _Wb (i, t) of the furnace wall bricks by furnace and cycle. ) And enter.
Further, the model formula calculation unit 1002b inputs the density ρ _G and the specific heats C _{p and G.}
Further, the model formula calculation unit 1002b inputs the passing air flow rate BHS (i, time) for each furnace and each time from the operation content instruction unit 1002a. Here, the value obtained by multiplying the time time to the furnace by-hourly pass blower flow BHS (i, time) is a gas volume V _G.
Then, the model formula calculation unit 1002b uses the input information and uses the model formulas ((19) to (21)) described above to calculate the heat balance at the time of the calculation target in the ventilation period. Is repeated. As a result of this calculation of the heat balance, the gas combustion temperature T _G (i, time) for each furnace and time and the temperature T _CH (i, time) for the heat storage brick for each furnace and cycle can be obtained. The model formula calculation unit 1002b outputs the gas combustion temperature _TG (i, time) for each furnace and each time to the air flow rate / temperature determination unit 1002c. The values of the heat transfer coefficients h _{G and CH} of the model formulas ((19) and (20)) are different between the time of combustion and the time of blowing.

<Blower flow rate / temperature determination unit 1002c>
The blast flow rate / temperature determination unit 1002c inputs the operation target value 801 (target blast temperature BT _ref (time), target blast flow rate BV _ref (time), target blast time BTime _ref (time)).
Further, the blower flow rate / temperature determination unit 1002c inputs the mixing / cooling flow rate Air (i, time) for each furnace and each time from the operation content instruction unit 1002a.
Further, the blower flow rate / temperature determination unit 1002c inputs the gas combustion temperature _TG (i, time) for each furnace / time from the model formula calculation unit 1002b.
Further, the blower flow rate and temperature determination unit 1002c inputs the cold air temperature T _CW.

Then, the blast flow rate / temperature determination unit 1002c obtains the target blast temperature BT _ref (time) and the target blast flow rate BV _ref (time) by the following equations (22) to (24) using the input information. "Blower flow rate BV (i, time + 3) by furnace / hour, passing air flow rate BHS (i, time + 3) by furnace / hour, mixed cooling flow rate Air (i, time + 3) by furnace / hour" ) ”Is calculated. Then, the blast flow rate / temperature determination unit 1002c determines the passing blast flow rate BHS (i, time + 3) for each furnace and time, and the mixed / cold flow rate Air (i, time + 3) for each furnace / time. Output to. That is, the passing air flow rate BHS (i, time + 3) for each furnace and time and the air-cooling flow rate Air (i, time + 3) for each furnace and time are the passing air flow rates for each furnace at the time to be calculated next. It becomes a mixed cooling flow rate.

The blast flow rate / temperature determination unit 1002c is used to obtain the “gas temperature _TG (i, time) by furnace / hour, passing blast flow rate BHS (i, time) by furnace / time,” obtained in the prediction interval 901. The mixed cooling flow rate Air (i, time) for each furnace and time is given to the right side of Eqs. (22) to (24), and the predicted value BT _p of the blast temperature for each furnace and cycle in the prediction interval 901. (I, t) is calculated.
Further, the blower flow rate and temperature determination unit 1002c is at the end of the blowing period of silica brick lower portion from the temperature T _CH of filtrated cycle another heat storage bricks obtained in (blowing end) (i, t) The temperature is extracted, and the extracted temperature is defined as the predicted value T _{si, p} (i, t) of the lower end temperature of the silica brick for each furnace and each cycle. The blast flow rate / temperature determination unit 1002c extracts the predicted values T _{si, p} (i, t) of the lower end temperature of the silica stone brick for each furnace and each cycle at the end of the blast period in the prediction interval 901, respectively. Do.

Then, the blast flow rate / temperature determination unit 1002c determines the predicted value BT _p (i, t) of the blast temperature for each furnace / cycle in the predicted section 901, and the lower end temperature of the silicate brick for each furnace / cycle in the predicted section 901. The predicted values T _{si, p} (i, t) of are output to the optimum tracking control unit 703 as predicted values of the process states of the hot air furnaces 100a to 100d.

Returning to the explanation of FIG. 7, the optimum tracking control unit 703 has described the predicted value T _{si, of the} minimum temperature of the silicate brick for each furnace and each cycle in the prediction interval 901 from the second process state prediction unit 704 as described above _{. p} (i, n + d + g) to T _{si, p} (i, n + m + g) and the predicted value BT _p (i, n + d + g) to BT _p (i, n + m + g) of the blast temperature for each furnace and cycle in the prediction interval 901. input. Then, the optimum tracking control unit 703 statistically determines how much the candidate values of the input heat amount Q _{in, p} (i, t) for each furnace and each cycle after the present time in the control section 902 should be changed. To judge. This is to minimize the value of the evaluation value of the furnace-specific objective function J ₁ (i) of the above-mentioned equation (11) within the range satisfying the constraint conditions of the equations (12) and (13). The optimum tracking control unit 703 performs the input heat amount Q _in, for each furnace and cycle after the present time in the control section 902 until the value of the evaluation value of the objective function J ₁ (i) for each furnace in Eq. (11) becomes the minimum _. The candidate values of _p (i, t) are changed, and the changed values are output to the second process state prediction unit 704.

Then, the optimum tracking control unit 703 performs the input heat amount Q _{in, p} for each furnace and each cycle after the present time when the value of the evaluation value of the objective function J ₁ (i) for each furnace in Eq. (11) becomes the minimum. Of (i, n) to Q _{in, p} (i, n + s + q-m) (candidate values), the input heat amount Q _{in, p} (i, n) for each furnace and each cycle is set as the target combustion pattern derivation unit. Output to 503. The heat input Q _{in, p} (i, n) for each furnace and cycle is the optimum heat input in the next combustion periods 402b and 402c.

The process model used to derive the target silica stone minimum temperature T _{si, ref} is not limited to the linear time series model. For example, a statistical analysis model other than the linear time series model may be used. Further, a process model (step response model or impulse response model) identified from the operation results of the hot air furnace 100 may be used. It is preferable to adopt a process model that derives the predicted value of the process state for each cycle because the calculation load can be reduced as described above. However, if the calculation load constraint is small, a hot air furnace simulator can be used. Good.

Further, if the second term on the right side of Eq. (11) is included in the objective function for each furnace, the fluctuation of the input heat amount Q _in (i, t) for each furnace and each cycle in the cycles adjacent to each other in the same hot air furnace 100 Is preferable because it can be reduced. However, even without this term, the predicted value T _{si, p} (i, t) of the minimum temperature of silica brick for each furnace and cycle in the prediction interval 901 can be obtained by the first term on the right side of equation (11). Targets for each cycle and each cycle Silica brick can be made to follow the minimum temperature T _{si, ref} (i, n + j) well. Therefore, the second term on the right side of Eq. (11) is not always necessary.

Further, the process model used when deriving the operation command values of the input heat amounts Q _{in and p} is not limited to the hot air furnace simulator. When the limitation of calculation accuracy is small, for example, a statistical analysis model such as the linear time series model described above may be used.
Further, the physical quantity that reflects the heat storage amount of the hot air furnace 100 is not limited to the minimum temperature of the silica stone brick as long as it is a measurable physical quantity. For example, it may be the exhaust gas temperature at the end of the combustion period.

In addition, as the predicted value of the process state, instead of the predicted value BT _p (i, t) of the blast temperature for each furnace / cycle, the predicted value of the minimum opening value of the cold air butterfly valve 123 for each furnace / cycle. KB _p (i, t) may be used. The minimum opening value of the cold air butterfly valve 123 for each furnace and cycle corresponds to the opening of the cold air butterfly valve 123 for each furnace and cycle at the end of the ventilation period. In the linear time series model, the predicted value KB _p (i, t) of the minimum opening value of the cold air butterfly valve 123 for each furnace and each cycle can be obtained by using the following equation (25).

In the equation (25), the coefficients a _{2 · x} (i), b _{2 · x} (i), and c _{2 · x} (i) are input based on the operation of the input device 312. These coefficients a _{2 · x} (i), b _{2 · x} (i), and c _{2 · x} (i) are also the coefficients a _{0 · x} (i), b _{0 · x} (i), c _{0 · x} ( It is obtained in advance in the same manner as in i).
ΔKB _p (i, n + j + 1) is expressed by the following equation (26).
ΔKB _p (i, n + j + 1) = KB _p (i, n + j + 1) -KB _p (i, n + j) ... (26)

ΔKB (i, n + j−x) is expressed by the following equation (27).
ΔKB (i, n + j-x) = KB (i, n + j-x) -KB (i, n + j-x-1) ... (27)
In this way, when the predicted value KB _p (i, t) of the minimum opening value of the cold air butterfly valve 123 for each furnace and each cycle is used as the predicted value for the process state, instead of the constraint condition in Eq. (17), , The constraint condition of the following equation (28) is used.
KB _p (i, t) ≥ Th ₄ ... (28)
Th ₄ is a threshold value, which is preset.

Further, the blowing temperature and the opening degree of the cold air butterfly valve 123 have a correlation. Therefore, by formulating these relationships, even if a hot air furnace simulator is used, the cold air butterfly valve 123 for each furnace and each cycle can be obtained from the predicted value BT _p (i, t) of the blowing temperature for each furnace and each cycle. The predicted value KB _p (i, t) of the lowest value of the opening degree of is can be obtained.

When not operating in the staggered parallel system, for example, when operating so that the cycles of the hot air furnaces 100a to 100d do not overlap each other, the operation target value may be different in each furnace (that is,). It may be the operation target value for each furnace and each hour).

(Combustion pattern acquisition unit 502)
As described above, in the present embodiment, the case where the combustion pattern acquisition unit 502 derives the optimum combustion pattern by using the technique described in Patent Document 5 will be described as an example.
FIG. 11 is a diagram showing an example of a detailed functional configuration of the combustion pattern acquisition unit 502.
The combustion pattern acquisition unit 502 solves the multi-objective optimization problem by using the multi-objective GA (genetic algorithm), and obtains a plurality of Pareto optimal solutions in advance. When the operating conditions are changed, the combustion pattern acquisition unit 502 selects one Pareto optimal solution that matches the changed operating conditions from the plurality of Pareto optimal solutions. Then, the combustion pattern acquisition unit 502 outputs the combustion pattern corresponding to the selected Pareto optimum solution as the optimum combustion pattern to the target combustion pattern derivation unit 503.

Here, the operating conditions include the state quantity of the hot air furnace 100 and the operating policy of the hot air furnace 100. The state quantity of the hot air furnace 100 is an amount (for example, temperature or air flow rate) that is directly or indirectly measured moment by moment by operating the hot air furnace 100. On the other hand, the operation policy of the hot air furnace 100 is decided by the operator based on the production plan and the production control.

The combustion pattern acquisition unit 502 includes an optimization unit 1110 and a process simulator 1150. The details of the optimization unit 1110 and the process simulator 1150 will be described below.
((Objective function setting unit 1111))
The objective function setting unit 1111 sets the objective function ΔP based on the operation of the input device 312 by the operator.
In the present embodiment, a plurality of evaluation quantities, which are indexes for evaluating the performance of the hot air furnace 100, are set as the objective function ΔP. Specifically, in the present embodiment, the case where the objective function ΔP is as shown in the following equation (29) will be described as an example.

ΔP = [ΔP1, ΔP2, ΔP3, ΔP4, ΔP5, ΔP6] ... (29)
Here, ΔP1, ΔP2, ΔP3, ΔP4, ΔP5, and ΔP6 of the equation (29) are represented by the equations (30) to (35), respectively.
ΔP1 = P11-P10 ... (30)
However, P11: thermal efficiency after changing the combustion pattern, P10: reference value of thermal efficiency ΔP2 = P21-P20 ... (31)
However, P21: the minimum temperature of silica stone brick after changing the combustion pattern, P20: the reference value of the minimum temperature of silica stone brick.

ΔP3 = P31-P30 ... (32)
However, P31: CO ₂ emissions after changing the combustion pattern, P30: reference value of CO ₂ emissions ΔP4 = P41-P40 ... (33)
However, P41: total flow rate of COG after changing the combustion pattern, P40: reference value of total flow rate of COG ΔP5 = P51-P50 ... (34)
However, P51: the average temperature of the exhaust gas after changing the combustion pattern, P50: the reference value of the average temperature of the exhaust gas.

ΔP6 = P61-P60 ... (35)
However, P61: heat input amount after changing the combustion pattern, P60: reference value of input heat amount In the following description, ΔP1 is the thermal efficiency, ΔP2 is the silicate brick temperature, and ΔP3 is the CO ₂ emission amount, if necessary. ΔP4 is referred to as COG total flow rate, ΔP5 is referred to as exhaust gas average temperature, and ΔP6 is referred to as input heat amount.

From the above, in the present embodiment, the objective function setting unit 1111 indicates that the thermal efficiency ΔP1, the siliceous brick temperature ΔP2, the CO ₂ emission amount ΔP3, the COG total flow rate ΔP4, the exhaust gas average temperature ΔP5, and the input heat amount ΔP6 are the objective function ΔP. Set.

((Constraint condition setting unit 1112))
The constraint condition setting unit 1112 sets the constraint conditions for deriving the combustion pattern based on the operation from the operator. In the present embodiment, the constraint conditions of the following equations (36) to (38) are set by the constraint condition setting unit 1112.
ΔP2 = 0 ・ ・ ・ (36)
P21 ≧ P2min ・ ・ ・ (37)
P41 ≤ P4max ... (38)
Here, P2min is the lower limit of the adjustable range of the temperature of the silica stone brick 111. Further, P4max is an upper limit value of the adjustable range of the total flow rate of COG.

((Pareto optimal solution derivation unit 1113))
The Pareto optimal solution derivation unit 1113 applies the multi-objective GA to solve the multi-objective optimization problem for the objective function ΔP set by the objective function setting unit 1111 to derive a plurality of Pareto optimal solutions. An example of the function of the Pareto optimal solution derivation unit 1113 will be described below.

The individual generation unit 1113a sets two sets (current generation and next generation) in which N individuals are contained, and randomly generates N individuals in the current generation.
The conversion unit 1113b converts N individuals generated by the individual generation unit 1113a into a combustion pattern.

FIG. 12 is a diagram showing an example of a combustion pattern. In this embodiment, a combustion pattern of a dome temperature U1, a C / B ratio U2, and a BFG flow rate U3 is required. The combustion pattern of the dome temperature U1 is the relationship between the dome temperature and the time in one combustion period. The combustion pattern of the BFG flow rate U3 is the relationship between the BFG flow rate and the time in one combustion period. The combustion pattern of the C / B ratio U2 is the initial target value of the C / B ratio in one combustion period.

FIG. 12A is a combustion pattern 1201 at the dome temperature U1. In FIG. 12A, T11 is the first switching time of the dome temperature U1 in one combustion period. T11max is the upper limit of the adjustable range of the first switching time T11 of the dome temperature U1. T11min is the lower limit of the adjustable range of the first switching time T11 of the dome temperature U1.

T12 is the second switching time of the dome temperature U1 in one combustion period. T12max is the upper limit of the adjustable range of the second switching time T12 of the dome temperature U1. T12min is the lower limit of the adjustable range of the second switching time T12 of the dome temperature U1.
It is necessary to set the combustion pattern 1201 of the dome temperature U1 so that the dome temperature U1 is changed within the adjustable range (T11min to T11max, T12min to T12max) of the switching times T11 and T12 of the dome temperature U1.

ΔU11 is the amount of change in the dome temperature U1 at the first switching time T11 of the dome temperature U1. ΔU11max is the upper limit of the adjustable range of the change amount of the dome temperature U1 at the first switching time T11 of the dome temperature U1. ΔU11min is the lower limit of the adjustable range of the change amount of the dome temperature U1 at the first switching time T11 of the dome temperature U1.

ΔU12 is the amount of change in the dome temperature U1 at the second switching time T12 of the dome temperature U1. ΔU12max is the upper limit of the adjustable range of the change amount of the dome temperature U1 at the second switching time T12 of the dome temperature U1. ΔU12min is the lower limit of the adjustable range of the change amount of the dome temperature U1 at the second switching time T12 of the dome temperature U1.
It is necessary that the combustion pattern 1201 of the dome temperature U1 falls within the adjustable range (ΔU11min to ΔU11max, ΔU12min to ΔU12max) of the change amounts ΔU11 and ΔU12 of the dome temperature U1. In the example shown in FIG. 12A, the value of the dome temperature U1 becomes smaller as time elapses in one combustion period. Therefore, the change amounts ΔU11 and ΔU12 of the dome temperature U1 have negative values. Therefore, the lower limit value ΔUmin is larger than the upper limit value ΔU11max of the adjustable range of the change amount of the dome temperature U1 (the absolute value is smaller in the lower limit value ΔUmin than the upper limit value ΔU11max).

FIG. 12B is a combustion pattern 1202 with a C / B ratio of U2. In FIG. 12B, ΔU21 is the amount of change in the C / B ratio from the target C / B ratio pattern (initial target value of the C / B ratio) in the previous combustion period. In FIG. 4, when the next combustion period is 402b, the previous combustion period is the combustion period 402a. ΔU21max is the upper limit of the adjustable range of the C / B ratio change amount ΔU21. ΔU21min is the lower limit of the adjustable range of the C / B ratio change amount ΔU21. It is necessary to make the combustion pattern 1202 of the C / B ratio U2 fall within the adjustable range (ΔU21min to ΔU21max) of the change amount ΔU21 of the C / B ratio.

FIG. 12C is a combustion pattern 1203 of the BFG flow rate U3. In FIG. 12 (c), T31 is the first switching time of the BFG flow rate U3 in one combustion period 402a, 402b, 402c. T31max is the upper limit of the adjustable range of the first switching time T31 of the BFG flow rate U3. T31min is the lower limit of the adjustable range of the first switching time T31 of the BFG flow rate U3.

T32 is the second switching time of the BFG flow rate U3 in one combustion period. T32max is the upper limit of the adjustable range of the second switching time T32 of the BFG flow rate U3. T32min is the lower limit of the adjustable range of the second switching time T32 of the BFG flow rate U3.
It is necessary to set the combustion pattern 1203 of the BFG flow rate U3 so that the BFG flow rate U3 is changed within the adjustable range (T31min to T31max, T32min to T32max) of the switching times T31 and T32 of the BFG flow rate U3.

ΔU31 is the amount of change in the BFG flow rate U3 at the first switching time T31 of the BFG flow rate U3. ΔU31max is the upper limit of the adjustable range of the change amount of the BFG flow rate U3 at the first switching time T31 of the BFG flow rate U3. ΔU31min is the lower limit of the adjustable range of the change amount of the BFG flow rate U3 at the first switching time T31 of the BFG flow rate U3.

ΔU32 is the amount of change in the BFG flow rate U3 at the second switching time T32 of the BFG flow rate U3. ΔU32max is the upper limit of the adjustable range of the change amount of the BFG flow rate U3 at the second switching time T32 of the BFG flow rate U3. ΔU32min is the lower limit of the adjustable range of the change amount of the BFG flow rate U3 at the second switching time T32 of the BFG flow rate U3.
It is necessary to make the combustion pattern 1203 of the BFG flow rate U3 fall within the adjustable range (ΔU31min to ΔU31max, ΔU32min to ΔU32max) of the change amounts ΔU31 and ΔU32 of the BFG flow rate U3.

As described above, in the present embodiment, the individual changes the dome temperature U1 change amounts ΔU11 and ΔU12, the dome temperature U1 switching times T11 and T12, the C / B ratio U2 change amount ΔU21, and the BFG flow rate U3. The quantities ΔU31 and ΔU32 and the switching times T11 and T12 of the BFG flow rate U3 are included. Further, in the present embodiment, the number of hot air furnaces 100a to 100d is four. Therefore, the individual generation unit 1113a determines that the dome temperature U1 is changed in ΔU11 and ΔU12, the dome temperature U1 is switched at T11 and T12, and the C / B ratio U2 is changed in ΔU21 for each of the hot air furnaces 100a to 100d. The change amounts ΔU31 and ΔU32 of the BFG flow rate U3 and the switching times T11 and T12 of the BFG flow rate U3 are generated. In FIG. 12A, the combustion pattern 1201 of the dome temperature U1 shows the sizes U11, U12, and U13 of the dome temperature U1 for convenience of notation. However, the combustion pattern 1201 of the dome temperature U1 does not include the magnitudes U11, U12, and U13 of the dome temperature U1. Similarly, FIG. 12C shows the sizes U31, U32, and U33 of the combustion pattern 1203 of the BFG flow rate U3 for convenience of notation. However, the combustion pattern 1203 of the BFG flow rate U3 does not include the sizes U31, U32, and U33 of the combustion pattern 1203 of the BFG flow rate U3.

In addition, in FIG. 12A and FIG. 12C, the case where the combustion patterns 1201 and 1203 change with an inclination of 90 [°] at the switching times T11, T12, T31, and T32 is shown as an example. However, it is not always necessary to do this, and the combustion pattern may be changed with an inclination other than 90 [°]. In this case, the individual generation unit 1113a also sets the inclination information for the individual.

Further, the dome temperature U1 at the combustion start time Ts is derived by the conversion unit 1113b. Further, the BFG flow rate U3 at the combustion start time Ts is automatically adjusted by the process simulator 1150 determining the weighted average value U3ave of the combustion pattern 1203 of the BFG flow rate U3 so that the blowing temperature satisfies the target value. To. Therefore, the individual does not contain this information. However, this information may be included in the individual.

Here, the weighted average value means a weighted average value in which the ratio of the period determined by the adjacent time to the time of one combustion period (time from the combustion start time Ts to the combustion end time Te) is used as a weighting coefficient. In the example shown in FIG. 12C, the period determined by the adjacent time is the period between the two time adjacent in time among the combustion start time Ts, the switching time T31, T32, and the combustion end time Te. .. That is, the period determined by the adjacent time is the period from the combustion start time Ts to the switching time T31, the period from the switching time T31 to the switching time T32, and the period from the switching time T32 to the combustion end time Te. In the example shown in FIG. 12C, the weighted average value U3ave of the combustion pattern 1203 of the BFG flow rate U3 is represented by the following equation (39a).
U3ave = {(T31-Ts) x U31 + (T32-T31) x U32 + (Te-T32) x U33} ÷ (Te-Ts) ... (39a)
Here, U31 is the BFG flow rate U3 in the period from the combustion start time Ts to the switching time T31. U32 is the BFG flow rate in the period from the switching time T31 to the switching time T32. U33 is the BFG flow rate in the period from the switching time T32 to the combustion end time Te.

Returning to the description of FIG. 11, the conversion unit 1113b returns to the combustion pattern 1201 of the dome temperature U1 so that the weighted average value of the combustion pattern 1201 of the dome temperature U1 becomes equal to the weighted average value of the previous target combustion pattern of the dome temperature U1. To determine. In the example shown in FIG. 12A, the period determined by the adjacent time is the period between the two time adjacent in time among the combustion start time Ts, the switching times T11 and T12, and the combustion end time Te. .. That is, the period determined by the adjacent time is the period from the combustion start time Ts to the switching time T11, the period from the switching time T11 to the switching time T12, and the period from the switching time T12 to the combustion end time Te. In the example shown in FIG. 12A, the weighted average value U1ave of the combustion pattern 1201 at the dome temperature U1 is represented by the following equation (39b).
U1ave = {(T11-Ts) x U11 + (T12-T11) x U12 + (Te-T12) x U13} ÷ (Te-Ts) ... (39b)
Here, U11 is the dome temperature U1 in the period from the combustion start time Ts to the switching time T11. U12 is the dome temperature U1 in the period from the switching time T11 to the switching time T12. U13 is the dome temperature U1 in the period from the switching time T12 to the combustion end time Te.

The simulation instruction unit 1113c indicates the combustion pattern 1201 of the dome temperature U1 for each of the four hot blast furnaces 100a to 100d and the C / B ratio for each of the four hot blast furnaces 100a to 100d with respect to the process simulator 1150. It is instructed to pass the combustion pattern 1202 of U2 and the individual of the BFG flow rate U3 for each of the four hot air furnaces 100a to 100d to perform the process simulation.
As shown in FIG. 11, the process simulator 1150 includes a process simulator 1150a for the hot air furnace 100a, a process simulator 1150b for the hot air furnace 100b, a process simulator 1150c for the hot air furnace 100c, and a process simulator 1150d for the hot air furnace 100d. Has. The process simulators 1150a to 1150d simulate an actual process control system by software (computer simulation). In the example shown in FIG. 11, the process simulator 1150a for the hot air furnace 100a models the controller model 1151a that models the controller, the physical model 1152a of the hot air furnace that models the configuration of the hot air furnace 100a, and the subtractor. Includes a modified subtractor model 1153a. The other process simulators 1150b to 1105d for the hot blast furnaces 100b to 100d also have the same configuration as the process simulator 1150a for the hot blast furnace 100a. However, the physical model of the hot blast furnace is different for each hot blast furnace. Therefore, here, an example of the process simulator 1150a for the hot air furnace 100a will be described, and detailed description of the process simulators 1150b to 1105d for the other hot air furnaces 100b to 100d will be omitted.

The controller controls the hot air furnace so that the measured values of the dome temperature U1, the C / B ratio U2, and the BFG flow rate U3 become the set values based on the instructions from the simulation instruction unit 1113c. The controller can control the hot air furnace by various known control methods such as PID control. The subtractor subtracts the measured values of the dome temperature U1, the C / B ratio U2, and the BFG flow rate U3 from the set values based on the instructions from the simulation instruction unit 1113c.

The process simulator 1150a extracts information indicating the operation results in the hot air furnace 100a. Then, the process simulator 1150a sets the initial value for executing the simulation based on the information indicating the operation results in the hot air furnace 100a.

After the initial values are set in this way, the process simulator 1150a simulates the operation of the actual process control system in the hot air furnace 100a by using the values instructed by the simulation instruction unit 1113c. When this simulation is completed, the process simulator 1150a uses the thermal efficiency ΔP1, the siliceous brick temperature ΔP2, the CO ₂ emission amount ΔP3, the COG total flow rate ΔP4, the exhaust gas average temperature ΔP5, and the input heat amount ΔP6, and the variables used to obtain them ( P10, P11, P20, P21, P30, P31, P40, P41, P50, P51, P60, P61) are output to the optimization unit 1110 (simulation result acquisition unit 1113d). The thermal efficiency ΔP1, the silica stone brick temperature ΔP2, the CO ₂ emission amount ΔP3, the COG total flow rate ΔP4, the exhaust gas average temperature ΔP5, and the input heat amount ΔP6 are obtained from the physical model 1152a of the hot air furnace. It is realized by this simulation that the weighted average value U3ave of the combustion pattern 1203 of the BFG flow rate U3 is obtained so that the blast temperature satisfies the target value.

The simulation result acquisition unit 1113d acquires the thermal efficiency ΔP1, the silicate brick minimum temperature ΔP2, the CO ₂ emission amount ΔP3, the COG total flow rate ΔP4, the exhaust gas average temperature ΔP5, and the input heat amount ΔP6 as evaluation quantities from the process simulators 1150a to 1150d.
The fitness derivation unit 1113e derives the fitness from the thermal efficiency ΔP1, the minimum temperature of silica stone brick ΔP2, the CO ₂ emission amount ΔP3, the COG total flow rate ΔP4, the exhaust gas average temperature ΔP5, and the input heat amount ΔP6. Since the fitness can be derived by a known method in multipurpose GA, detailed description thereof will be omitted.

In the constraint condition determination unit 1113f, the silica stone brick temperature ΔP2, the minimum silica stone temperature P21 after changing the combustion pattern, and the total COG flow rate P41 after changing the combustion pattern are set by the constraint condition setting unit 1112. It is determined whether or not the constraint conditions (Equations (36) to (38)) are satisfied.
When the constraint condition determination unit 1113f determines that the constraint condition is satisfied, the fitness determination unit 1113g selects the fitness derived by the fitness derivation unit 1113e. On the other hand, when the constraint condition determination unit 1113f determines that the constraint condition is not satisfied, the fitness determination unit 1113g cancels the fitness derived by the fitness derivation unit 1113e and sets the minimum value as the fitness. To do. By doing so, the total of "silica brick temperature ΔP2, minimum silica stone temperature P21 after changing the combustion pattern, and COG after changing the combustion pattern" corresponding to the fitness when the constraint condition is not satisfied. The flow rate P41 ”is prevented from being output from the Pareto optimum solution unit 1113h.

The processing of the conversion unit 1113b, the simulation instruction unit 1113c, the simulation result acquisition unit 1113d, the fitness derivation unit 1113e, the constraint condition determination unit 1113f, and the fitness determination unit 1113g is performed by N pieces generated by the individual generation unit 1113a. It is done individually for each individual.
The Pareto optimal solution unit 1113h performs any of crossover, mutation, and copying on the individual generated by the individual generation unit 1113a with a certain probability, and saves the result to the next generation. Then, when the number of next-generation individuals becomes N by this processing, the Pareto optimal solution unit 1113h deletes the current-generation individuals and transfers all the next-generation individuals to the current generation.

Then, the operations of the above conversion unit 1113b, simulation instruction unit 1113c, simulation result acquisition unit 1113d, fitness derivation unit 1113e, constraint condition determination unit 1113f, fitness determination unit 1113g, and Pareto optimal solution unit 1113h are performed in the maximum generation. Repeat until it reaches a few G. Then, the Pareto optimal solution unit 1113h finally evaluates the (plural) individuals with the highest fitness among the individuals included in the current generation (ΔP1, ΔP2, ΔP3, ΔP4, ΔP5, ΔP6). And the combustion pattern for the individual are output to the Pareto optimal solution storage unit 1114.

((Pareto optimal solution storage unit 1114))
The Pareto optimal solution storage unit 1114 stores the evaluation amount (ΔP1, ΔP2, ΔP3, ΔP4, ΔP5, ΔP6) of the individual and the combustion pattern for the individual in association with each other.
FIG. 13 is a diagram showing an example of a Pareto optimal solution. In the present embodiment, there are six objective functions ΔP (ΔP1, ΔP2, ΔP3, ΔP4, ΔP5, ΔP6), but for the sake of visual clarity, here, the two objective functions ΔP1 and ΔP2 are described. The Pareto optimal solution is shown.
In FIG. 13, a case where seven Pareto optimal solutions Z1 to Z7 are obtained is shown as an example. Therefore, in the example shown in FIG. 13, the Pareto optimal solution storage unit 1114 has the values of these seven Pareto optimal solutions Z1 to Z7 (values of ΔP1 to ΔP6) and the combustion patterns corresponding to the Pareto optimal solutions Z1 to Z7. Will be associated with each other and memorized.

((Operation Policy Acquisition Department 1115))
Returning to the description of FIG. 11, the operation policy acquisition unit 1115 inputs the information regarding the operation policy input by the operator.

((Plant status / evaluation amount acquisition unit 1116))
The plant state / evaluation amount acquisition unit 1116 converts the state amount (actual value) of the hot air furnaces 100a to 100d and the evaluation amounts ΔP1 to ΔP6 (actual value) of the hot air furnaces 100a to 100d into the hot air furnaces 100a to 100d. Obtained from various measuring instruments provided.
The state quantity of the hot air furnaces 100a to 100d is an amount (for example, temperature or air flow rate) that is directly or indirectly measured moment by moment by operating the hot air furnace 100. On the other hand, the evaluation amounts ΔP1 to ΔP6 in the hot air furnaces 100a to 100d are indexes for evaluating the performance of the hot air furnaces 100a to 100d. The evaluation quantities ΔP1 to ΔP6 in the hot blast furnaces 100a to 100d are, for example, those of the hot blast furnaces 100a to 100d acquired over a period longer than the cycle in which the state quantities of the hot blast furnaces 100a to 100d are acquired (for example, in units of one day). Calculated based on the state quantity.

The evaluation quantities ΔP1 to ΔP6 (actual values) in the hot air furnaces 100a to 100d are used, for example, by the optimization unit 1110 to tune the process simulator 1150. On the other hand, the state quantities of the hot air furnaces 100a to 100d are used by the operating condition change determination unit 1117 to determine whether or not the operating conditions have been changed.

((Operating condition change judgment unit 1117))
The operating condition change determination unit 1117 determines whether or not the operating conditions of the hot air furnace 100 have been changed. This determination is based on the operation policy acquired by the operation policy acquisition unit 1115 and the state quantity (actual value) of the hot air furnace 100 acquired by the plant condition / evaluation quantity acquisition unit 1116, and the operation policy and the hot air furnace. It is performed by determining whether or not at least one of the state quantities of 100a to 100d has been changed. In the present embodiment, the operating policy and the state quantities of the hot air furnaces 100a to 100d are included in the operating conditions of the hot air furnaces 100a to 100d. Therefore, the operating condition change determination unit 1117 determines that the operating conditions of the hot air furnaces 100a to 100d have been changed when at least one of the operating policy and the state quantity of the hot air furnaces 100a to 100d is changed.

((Pareto optimal solution candidate display unit 1118))
When the operating condition change determination unit 1117 determines that the operating conditions of the hot air furnaces 100a to 100d have been changed, the Pareto optimal solution candidate display unit 1118 stores a plurality of Pareto optimal solution storage units 1114. A GUI for allowing the operator to select Z1 to Z7 (that is, a combustion pattern) is displayed on the display device 303.
FIG. 14 is a diagram showing an example of a GUI for causing an operator to change the Pareto optimal solutions Z1 to Z7.

In FIG. 14, the GUI 1400 includes changes in operating conditions, Pareto optimal solutions (names) Z1 to Z7, evaluation quantities ΔP1 to ΔP6 that determine the values of the Pareto optimal solutions Z1 to Z7, and evaluation quantities ΔP1 to the same. The superiority or inferiority of ΔP6 is displayed. Further, the currently selected Pareto optimal solution (Pareto optimal solution Z3 in the example shown in FIG. 14) is surrounded by a square.
Here, the superiority or inferiority of the evaluation quantities ΔP1 to ΔP6 indicates the relative superiority or inferiority of the evaluation quantities ΔP1 to ΔP6 in each Pareto optimal solution Z1 to Z7. For example, when the Pareto optimum solution Z3 is selected, the operation is excellent in the order of COG total flow rate ΔP4, CO ₂ emission amount ΔP3, silica brick temperature ΔP2, thermal efficiency ΔP1, input heat amount ΔP6, and exhaust gas average temperature ΔP5.

In the present embodiment, by operating the GUI 1400, either one of the Pareto optimal solutions Z1 to Z7 is manually selected by the user, or the combustion pattern acquisition unit 502 automatically selects one of them. Will be.
When the user manually selects any of the Pareto optimal solutions Z1 to Z7, the operator first looks at the GUI 1400 and determines which Pareto optimal solution should be changed to the currently selected Pareto optimal solution. Then, the operator moves the arrow 1401 displayed on the GUI 1400 by operating the input device 312. Then, the arrow 1401 is displayed beside the Pareto optimal solution desired by the operator. The operator then operates the input device 312 to press the manual button 1402 to determine the Pareto optimal solution to be changed.

On the other hand, when the combustion pattern acquisition unit 502 automatically selects any of the Pareto optimal solutions Z1 to Z7, the operator operates the input device 312 and presses the automatic button 1403. Then, one of the Pareto optimal solutions Z1 to Z7 is automatically selected as described later.
In addition to the information shown in FIG. 14, the Pareto optimal solution candidate display unit 1118 may display information indicating the combustion pattern in each Pareto optimal solution on the GUI 1400.

((Pareto optimal solution acquisition determination unit 1119))
The Pareto optimal solution acquisition determination unit 1119 determines which of the manual button 1402 and the automatic button 1403 is pressed by the operator's operation on the GUI 1400.

((Weight coefficient derivation unit 1120))
When the weighting coefficient derivation unit 1120 determines that the automatic button 1403 has been pressed by the Pareto optimal solution acquisition determination unit 1119, the thermal efficiency ΔP1, the silicate brick temperature ΔP2, and the CO ₂ emission amount are based on the information of the changed operating conditions. The weighting coefficient W for each of ΔP3, COG total flow rate ΔP4, exhaust gas average temperature ΔP5, and input heat amount ΔP6 is calculated. The weighting coefficient W is expressed by the following equation (40).

W = [W1, W2, W3, W4, W5, W6] ... (40)
W1 is a weighting coefficient of thermal efficiency ΔP1, W2 is a weighting coefficient of silica brick temperature ΔP2, W3 is a weighting coefficient of CO ₂ emission amount ΔP3, W4 is a weighting coefficient of COG total flow rate ΔP4, W5 is a weighting coefficient of exhaust gas average temperature ΔP5, W6. Is the weighting coefficient of the input heat amount ΔP6. The values of the weighting coefficients W1 to W6 are 0 or more and 1 or less, and the sum of them is 1. For example, when the thermal efficiency ΔP1 is maximized, the weighting coefficient W becomes, for example, the following equation (41). As described above, the weighting coefficient W represents the relative importance of the evaluation quantities ΔP1 to ΔP6. The higher the importance of the evaluation quantity, the larger the magnitude of the weighting coefficient of the evaluation quantity.
W = [1,0,0,0,0,0] ... (41)

((Evaluation function derivation unit 1121))
The evaluation function derivation unit 1121 uses the weighting coefficient W derived by the weighting coefficient derivation unit 1120 and the values of the Pareto optimum solutions Z1 to Z7 (values of ΔP1 to ΔP6) stored in the Pareto optimum solution storage unit 1114. Then, the evaluation function Q is derived by the following equation (42). As a result, the weighted sum of the evaluation values based on the weighting coefficients W1 to W6 is derived. At this time, the evaluation function derivation unit 1121 performs a normalization process on each of the evaluation quantities ΔP1 to ΔP6 so that the evaluation quantities ΔP1 to ΔP6 have substantially the same fluctuation range. Therefore, ΔP _{r in} Eq. (42) indicates a normalized evaluation quantity. Further, the evaluation function derivation unit 1121 has a value (ΔP) of the Pareto optimum solution Z stored in the Pareto optimum solution storage unit 1114 for the evaluation amount to be maximized such as the thermal efficiency ΔP1 among the evaluation quantities ΔP1 to ΔP6. (Value of) is multiplied by "-1". Therefore, of the ΔP _{r in} the equation (42), the sign (positive or negative) of the evaluation quantity to be maximized is different from that stored in the Pareto optimal solution storage unit 1114.
Here, the value of the Pareto optimal solution Z (value of ΔP) stored in the Pareto optimal solution storage unit 1114 is subjected to normalization processing and multiplication processing of "-1". The processed product may be stored in the Pareto optimal solution storage unit 1114.

In equation (42), s is the number of evaluation quantities ΔP. In this embodiment, since there are six evaluation quantities ΔP1 to ΔP6, s = 6. W _r is a weighting coefficient for each evaluation quantity ΔP _r . In the present embodiment, the weighting factor W _r will weighting factor W1~W6 described above.

((Pareto optimal solution selection unit 1122))
The Pareto optimal solution selection unit 1122 is the most appropriate of the Pareto optimal solutions Z1 to Z7 stored in the Pareto optimal solution storage unit 1114 based on the seven evaluation functions Q derived by the evaluation function derivation unit 1121. Select the Pareto optimal solution. Specifically, in the present embodiment, the Pareto optimal solution selection unit 1122 selects the smallest evaluation function Q from the seven evaluation functions Q derived by the evaluation function derivation unit 1121, and corresponds to the evaluation function Q. Select the Pareto optimal solution. That is, in the present embodiment, the Pareto optimal solution selection unit 1122 selects the Pareto optimal solution that minimizes the weighted sum based on the evaluation value of the weighting coefficient after the operating conditions are changed.

((Combustion pattern changing unit 1123, combustion pattern storage unit 1124))
When the combustion pattern changing unit 1123 determines that the manual button 1402 is pressed by the Pareto optimum solution acquisition determination unit 1119, the combustion pattern changing unit 1123 sets a target value pattern corresponding to the Pareto optimum solution selected by the operator in the GUI 1400 shown in FIG. Read from Pareto optimal solution storage unit 1114.
On the other hand, when it is determined by the Pareto optimal solution acquisition determination unit 1119 that the automatic button 1403 is pressed, the combustion pattern corresponding to the Pareto optimal solution selected by the Pareto optimal solution selection unit 1122 is read from the Pareto optimal solution storage unit 1114. Then, the combustion pattern changing unit 1123 rewrites the optimum combustion pattern stored in the combustion pattern storage unit 1124 with the read combustion pattern.

((Combustion pattern output unit 1125))
When the optimum combustion pattern stored in the combustion pattern storage unit 1124 is updated, the combustion pattern output unit 1125 outputs the updated optimum combustion pattern to the target combustion pattern derivation unit 503.

The Pareto optimum solution selection unit 1122 may automatically select the Pareto optimum solution as shown in FIG. 15 according to the constraint conditions set by the constraint condition setting unit 1112. FIG. 15 is a diagram conceptually explaining a modified example of the method of automatically selecting the Pareto optimum solution. Here, it is assumed that the constraint condition is the following equation (43).
ΔP2 ≦ T ₀ ... (43)
In this case, the Pareto optimal solution selection unit 1122 is not all the Pareto optimal solutions Z1 to Z7 stored in the Pareto optimal solution storage unit 1114, but is the most among the Pareto optimal solutions Z1 to Z4 satisfying the equation (43). Select the appropriate Pareto optimal solution. In this case, it is possible not to obtain the weighting coefficient W and the evaluation function Q for the Pareto optimal solutions Z5 to Z7. Therefore, the process for automatically selecting the Pareto optimal solution can be further simplified.

Further, the combustion pattern acquisition unit 502 may update a plurality of Pareto optimum solutions stored in the Pareto optimum solution storage unit 1114 at regular intervals.
The reference values P10, P20, P30, P40, P50, P60 (see equations (30) to (35)) of the evaluation quantities ΔP1 to ΔP6 vary depending on the operating conditions and disturbances. As a result, the adjustable range of the dome temperature U1, the C / B ratio U2, and the BFG flow rate U3 (ΔU11min to ΔU11max, ΔU12min to ΔU12max, ΔU21min to ΔU21max, ΔU31min to ΔU31max, ΔU32min to ΔU32max,), the range of the constraint conditions, and The sensitivity of fluctuations in the evaluation amounts ΔP1 to ΔP6 with respect to fluctuations in the dome temperature U1, the C / B ratio U2, and the BFG flow rate U3 changes. Therefore, the combustion pattern is changed, and the change in the combustion pattern changes the result of the simulation by the process simulator 1150 and the fitness. Therefore, the Pareto optimal solution finally obtained is also changed. Therefore, since the Pareto optimal solution selection unit 1122 automatically selects according to the constraint conditions, it becomes possible to select a more appropriate Pareto optimal solution in response to fluctuations in operating conditions and disturbances.

Further, the method for obtaining a plurality of Pareto optimal solutions is not limited to the multipurpose GA. For example, instead of the multipurpose GA, a plurality of Pareto optimal solutions can be obtained by using various algorithms such as NSGA-II and NCGA. Further, when a sufficient time for obtaining a plurality of Pareto optimal solutions can be secured, the following may be performed. That is, the optimization unit 1110 applies the weighting coefficient method to a plurality of objective functions, converts the plurality of objective functions into a single objective function, and optimizes the single objective such as the mountain climbing method while changing the weighting coefficient. A method may be used to find multiple Pareto optimal solutions.

Further, in the present embodiment, a case where the operator can manually select one of a plurality of Pareto optimal solutions and a case where the combustion pattern acquisition unit 502 automatically selects one of them can be performed. Only one of these may be performed.

Further, the combustion pattern acquisition unit 502 does not necessarily have to derive the optimum combustion pattern of the C / B ratio. This is because the target combustion pattern deriving unit 503 does not use the optimum combustion pattern of the C / B ratio.

(Target combustion pattern derivation unit 503)
FIG. 16 is a diagram showing an example of a detailed functional configuration of the target combustion pattern deriving unit 503.
As shown in FIG. 16, the target combustion pattern derivation unit 503 includes a target dome temperature derivation unit 1601, an input heat quantity ratio derivation unit 1602, a target C / B ratio derivation unit 1603, a target BFG flow rate derivation unit 1604, and a target. It has a combustion pattern output unit 1605.

((Target dome temperature derivation unit 1601))
The target dome temperature derivation unit 1601 derives a target combustion pattern of the dome temperature. The target combustion pattern of the dome temperature is the target combustion pattern of the dome temperature in the next combustion period. FIG. 17 is a diagram illustrating an example of a method for deriving a target combustion pattern of the dome temperature. FIG. 17A is a diagram showing an example of the previous target combustion pattern of the dome temperature. The previous target combustion pattern of the dome temperature is the target combustion pattern of the dome temperature in the previous combustion period. FIG. 17B is a diagram showing an example of the optimum combustion pattern of the dome temperature. The optimum combustion pattern of the dome temperature is the optimum combustion pattern of the dome temperature in the next combustion period. The optimum combustion pattern of the dome temperature in the next combustion period is derived by the combustion pattern acquisition unit 502. FIG. 17C is a diagram showing an example of a target combustion pattern of the dome temperature. In this embodiment, there are four hot air furnaces 100a to 100d. Therefore, the previous target combustion pattern of the dome temperature shown in FIG. 17A, the optimum combustion pattern of the dome temperature shown in FIG. 17B, and the target combustion pattern of the dome temperature shown in FIG. 17C are respectively. Obtained every 100a to 100d of hot air furnace.

The target dome temperature derivation unit 1601 derives the weighted average value DTave of the previous target combustion pattern of the dome temperature by the following equation (44).
DTave = {D11 × (T11-Ts) + D12 × (T12-T11) + D13 × (Ts-T12)} ÷ (Te-Ts) ・ ・ ・ (44)
Here, as shown in FIG. 17A, D11 is 1350 [° C.], D12 is 1320 [° C.], D13 is 1300 [° C.], T11-Ts is 20 [min], and T12-T11 is 15 [min]. ], Te-Ts is 71 [min]. In this case, the weighted average value DTave of the previous target combustion pattern of the dome temperature is 1318.31 [° C.] (= {1350 × 20 + 1320 × 15 + 1300 × (71-20-15)} ÷ 71).

Next, the target dome temperature derivation unit 1601 derives the weighted average value DMave of the optimum combustion pattern of the dome temperature by the following equation (45).
DMave = {D21 × (T11-Ts) + D22 × (T12-T11) + D23 × (Ts-T12)} ÷ (Te-Ts) ・ ・ ・ (45)
Here, as shown in FIG. 17B, D21 is 1300 [° C.], D22 is 1250 [° C.], D23 is 1230 [° C.], T11-Ts is 10 [min], and T12-T11 is 30 [min]. ], Te-Ts is 71 [min]. In this case, the weighted average value DMave of the optimum combustion pattern of the dome temperature is 1248.31 [° C.] (= {1300 × 10 + 1250 × 30 + 1230 × (71-10-30)} ÷ 71).

Next, the target dome temperature derivation unit 1601 derives the difference between the optimum combustion pattern value of the dome temperature and the weighted average value DMave by the following equations (46a) to (46c) for each period determined by the adjacent time. To do. As described above, the period determined by the adjacent time is the period between the two time adjacent to each other in time among the combustion start time Ts, the switching times T11 and T12, and the combustion end time Te. In the present embodiment, the period determined by the adjacent time is the period from the combustion start time Ts to the switching time T11, the period from the switching time T11 to the switching time T12, and the period from the switching time T12 to the combustion end time Te. .. Here, the period from the combustion start time Ts to the switching time T11 is set as the first time zone. The period from the switching time T11 to the switching time T12 is set as the second time zone. The period from the switching time T12 to the combustion end time Te is set as the third time zone. Of the difference between the optimum combustion pattern value of the dome temperature and the weighted average value DMave, the difference in the first time zone is defined as ΔTD1. Of the difference between the optimum combustion pattern value of the dome temperature and the weighted average value DMave, the difference in the second time zone is defined as ΔTD2. Of the difference between the optimum combustion pattern value of the dome temperature and the weighted average value DMave, the difference in the third time zone is defined as ΔTD3.

ΔTD1 = D21-DMave ... (46a)
ΔTD2 = D22-DMave ... (46b)
ΔTD1 = D23-DMave ... (46c)
In the above example, the difference ΔTD1 in the first time zone is 51.69 [° C.] (= 1300-1248.31). The difference ΔTD2 in the second time zone is 1.69 [° C.] (= 1250-1248.31). The difference ΔTD3 in the third time zone is -18.31 [° C.] (= 1230-1248.31).

Next, the target dome temperature derivation unit 1601 determines the dome temperature in the first time zone, the second time zone, and the third time zone according to the following equations (47a), (47b), and (47c). The target combustion patterns D31, D32, and D33 are derived. That is, the target dome temperature derivation unit 1601 sets the weighted average value DTave of the previous target combustion pattern of the dome temperature to the difference ΔTD1 in the first time zone, the difference ΔTD2 in the second time zone, and the difference in the third time zone. Add ΔTD3 respectively.
D31 = ΔTD1 + DTave ・ ・ ・ (47a)
D32 = ΔTD2 + DTave ・ ・ ・ (47b)
D33 = ΔTD3 + DTave ・ ・ ・ (47c)

In the above example, as shown in FIG. 17C, the target combustion pattern D31 of the dome temperature in the first time zone is 1370 [° C.] (= 51.69 + 1318.31). The target combustion pattern D32 of the dome temperature in the second time zone becomes 1320 [° C.] (= 1.69 + 1318.31). The target combustion pattern D33 of the dome temperature in the third time zone becomes 1300 [° C.] (= -18.31 + 1318.31).
The target dome temperature derivation unit 1601 connects the target combustion patterns D31, D32, and D33 of the dome temperature in the first time zone, the second time zone, and the third time zone with the target combustion pattern of the dome temperature. To do. By doing so, the weighted average value of the target combustion pattern of the dome temperature can be matched with the weighted average value DTave of the previous target combustion pattern of the dome temperature.

Next, the target dome temperature derivation unit 1601 determines whether or not the target combustion pattern of the dome temperature derived by the equations (47a) to (47c) deviates from the upper and lower limit values of the dome temperature. The upper and lower limits of the dome temperature are set in advance in the hot air furnace control calculation device 301 by the operator using the input device 312, for example, from the viewpoint of whether or not the hot air furnaces 100a to 100d are properly operated.

When the target combustion pattern of the dome temperature derived by the equations (47a) to (47c) does not deviate from the upper and lower limit values of the dome temperature, the target dome temperature derivation unit 1601 sets the target combustion pattern of the dome temperature. It is determined as the target combustion pattern of the dome temperature output to the flow control meters 304a to 304b and the like.
The target dome temperature derivation unit 1601 changes the target combustion pattern of the dome temperature when the target combustion pattern of the dome temperature derived by the equations (47a) to (47c) is out of the range of the upper and lower limits of the dome temperature. .. FIG. 18 is a diagram illustrating an example of a method of changing the target combustion pattern of the dome temperature. FIG. 18A is a diagram showing an example of a target combustion pattern of the dome temperature before the change. The target combustion pattern of the dome temperature before the change is the target combustion pattern of the dome temperature derived by the equations (47a) to (47c). FIG. 18B shows an example of the target combustion pattern of the changed dome temperature.

The target dome temperature derivation unit 1601 determines whether or not the target combustion pattern of the dome temperature before the change has a value higher than the upper limit value or a value lower than the lower limit value for each of the first to third time zones. As a result of this determination, when there is a time zone exceeding the upper limit value, the target dome temperature derivation unit 1601 changes the value of the target combustion pattern of the dome temperature before the change in the time zone to the upper limit value. When there is a time zone below the lower limit value, the target dome temperature derivation unit 1601 changes the value of the target combustion pattern of the dome temperature before the change in the time zone to the lower limit value. In the example shown in FIG. 18A, the target combustion pattern D31 (= 1370) of the dome temperature in the first time zone (Ts to T11) exceeds the upper limit value D3max (= 1360). Therefore, as shown in FIG. 18B, the target dome temperature derivation unit 1601 changes the target combustion pattern D31 of the dome temperature in the first time zone to the upper limit value D3max. Further, in the example shown in FIG. 18A, the target combustion pattern D33 (= 1300) of the dome temperature in the third time zone (T12 to Te) is below the lower limit value D3min (= 1310). Therefore, as shown in FIG. 18B, the target dome temperature derivation unit 1601 changes the value of the target combustion pattern of the dome temperature in the third time zone to the lower limit value D3min. Then, the target dome temperature derivation unit 1601 determines the changed target combustion pattern of the dome temperature shown in FIG. 18B as the target combustion pattern of the dome temperature output to the flow control meters 304a to 304b and the like.

((Charge ratio derivation unit 1602))
The input heat amount ratio derivation unit 1602 derives the ratio (= Qin-1 / Qin-0) of the next optimum input heat amount Qin-1 to the previous optimum input heat amount Qin-0. In the following description, this ratio will be referred to as the input heat amount ratio, if necessary. The previous optimum heat input Qin-0 and the next optimum heat input Qin-1 are derived by the input heat acquisition unit 501. Further, in the present embodiment, there are four hot air furnaces 100a to 100d. Therefore, the input heat amount ratio derivation unit 1602 derives the input heat amount ratio for each of the hot air furnaces 100a to 100d. For example, it is assumed that the previous optimum heat input Qin-0 for the hot air furnace 100a is 600123 [J] and the next optimum heat input Qin-1 for the hot air furnace 100a is 623001 [J]. In this case, the input heat amount ratio out-licensing unit 1602 derives 1.0381222 (= 623001 ÷ 600123) as the input heat amount ratio with respect to the hot air furnace 100a.

((Target C / B ratio derivation unit 1603))
The target C / B ratio derivation unit 1603 derives the target combustion pattern of the C / B ratio. FIG. 19 is a diagram illustrating an example of a method for deriving a target combustion pattern of the C / B ratio. The target combustion pattern of the C / B ratio is the initial target value of the C / B ratio in the next combustion period. FIG. 19A is a diagram showing an example of the previous target combustion pattern of the C / B ratio. The previous target combustion pattern of the C / B ratio is the target combustion pattern (initial target value) of the C / B ratio in the previous combustion period. FIG. 19B is a diagram showing an example of a target combustion pattern of C / B ratio. In this embodiment, there are four hot air furnaces 100a to 100d. Therefore, the previous target combustion pattern of the C / B ratio shown in FIG. 19A and the target combustion pattern of the C / B ratio shown in FIG. 19B are obtained for each of the hot air furnaces 100a to 100d, respectively. In FIGS. 19 (a) and 19 (b), the C / B ratio is changed from the initial target values C11 and C12 of the C / B ratio by the feedback control by the PID controller described above. It is shown together with the initial target values C11 and C12 of.

The target C / B ratio derivation unit 1603 derives the target combustion pattern C12 of the C / B ratio by the following equation (48). That is, the target C / B ratio derivation unit 1603 multiplies the previous target combustion pattern C11 of the C / B ratio by the input heat amount ratio (= Qin-1 / Qin-0).
C12 = C11 × Qin-1 / Qin-0 ・ ・ ・ (48)

Next, the target C / B ratio derivation unit 1603 determines whether or not the target combustion pattern of the C / B ratio derived by the equation (48) is out of the range of the upper and lower limits of the C / B ratio. The upper and lower limits of the C / B ratio are set in advance in the hot air furnace control calculation device 301 by the operator using the input device 312, for example, from the viewpoint of whether or not the hot air furnaces 100a to 100d are properly operated.

The target C / B ratio derivation unit 1603 is the target of the C / B ratio when the target combustion pattern of the C / B ratio derived by the equation (48) does not deviate from the upper and lower limit values of the C / B ratio. The combustion pattern is determined as a target combustion pattern of the C / B ratio output to the flow control meters 304a to 304b and the like.
When the target combustion pattern of the C / B ratio derived by the equation (48) is out of the range of the upper and lower limits of the C / B ratio, the target C / B ratio derivation unit 1603 has the target combustion pattern of the C / B ratio. To change. In the present embodiment, when the target combustion pattern of the C / B ratio before the change exceeds the upper limit of the C / B ratio, the target C / B ratio derivation unit 1603 determines the target combustion of the C / B ratio before the change. Change the value of the pattern to the upper limit. When the target combustion pattern of the C / B ratio before the change is lower than the lower limit of the C / B ratio, the target C / B ratio derivation unit 1603 sets the value of the target combustion pattern of the C / B ratio before the change. Change to the lower limit. The target C / B ratio derivation unit 1603 determines the changed target combustion pattern of the C / B ratio as the target combustion pattern of the C / B ratio output to the flow rate controllers 304a to 304b and the like.

((Target BFG flow rate derivation unit 1604))
The target BFG flow rate derivation unit 1604 derives the target BFG flow rate. The target combustion pattern of the BFG flow rate is the target combustion pattern of the BFG flow rate in the next combustion period. FIG. 20 is a diagram illustrating an example of the first step of the method of deriving the target BFG flow rate. FIG. 21 is a diagram illustrating an example of the second stage of the method of deriving the target BFG flow rate.

FIG. 20A is a diagram showing an example of the previous target combustion pattern of the BFG flow rate. The previous target combustion pattern of the BFG flow rate is the target combustion pattern of the BFG flow rate in the previous combustion period.
The target BFG flow rate derivation unit 1604 is a value obtained by multiplying the previous target combustion pattern of the BFG flow rate by the input heat amount ratio (= Qin-1 / Qin-0) as shown in the following equations (49a) to (49c). B21, B22, and B23 are derived. In the following description, the product of the previous target combustion pattern of the BFG flow rate and the input heat amount ratio (= Qin-1 / Qin-0) is referred to as a first BFG flow rate pattern, if necessary.
B21 = B11 × Qin-1 / Qin-0 ・ ・ ・ (49a)
B22 = B12 × Qin-1 / Qin-0 ・ ・ ・ (49b)
B23 = B13 × Qin-1 / Qin-0 ・ ・ ・ (49c)

FIG. 20B is a diagram showing an example of the first BFG flow rate pattern. Here, as shown in FIG. 20A, it is assumed that B11 is 125 [kNm ³ / hr], B12 is 128 [kNm ³ / hr], and B13 is 130 [kNm ³ / hr]. .. Further, it is assumed that the input heat amount ratio to the hot air furnace 100a is 1.0381222 described above. In this case, as shown in FIG. 20B, the value B21 of the first BFG flow rate pattern in the first time zone is 130 [kNm ^{3 /} hr] (= 125 × 1.0381222). Further, the value B22 of the first BFG flow rate pattern in the second time zone becomes 133 [kNm ^{3 /} hr] (= 128 × 1.0381222). Further, as shown in FIG. 20B, the value B23 of the first BFG flow rate pattern in the third time zone is 135 [kNm ^{3 /} hr] (= 130 × 1.0381222). Here, the value after the decimal point is rounded off (the same shall apply hereinafter). Further, as shown in FIG. 20B, in the first BFG flow rate pattern, T31-Ts is 25 [min], T32-T31 is 20 [min], and Te-Ts is 71 [min]. .. According to the first BFG flow rate pattern, the previous target combustion pattern of the BFG flow rate can be changed according to the input heat amount ratio (= Qin-1 / Qin-0).

FIG. 20C is a diagram showing an example of the optimum combustion pattern of the BFG flow rate. The optimum combustion pattern of the BFG flow rate is the optimum combustion pattern of the BFG flow rate in the next combustion period. The optimum combustion pattern of the BFG flow rate in the next combustion period is derived by the combustion pattern acquisition unit 502.
Next, the target BFG flow rate derivation unit 1604 derives the difference in the optimum combustion pattern of the BFG flow rate in the two time zones adjacent to each other. In the example shown in FIG. 20 (c), the difference between the first time zone and the second time zone of the optimum combustion pattern of the BFG flow rate ΔB1 (= B32-B31) and the second time of the optimum combustion pattern of the BFG flow rate. The difference between the band and the third time band ΔB2 (= B33-B32) is derived. Specifically, the target BFG flow rate derivation unit 1604 derives 8 [kNm ³ / hr] (= 128-120) as ΔB1. Further, the target BFG flow rate derivation unit 1604 derives 2 [kNm ³ / hr] (= 130-128) as ΔB2. Here, as shown in FIG. 20 (c), in the optimum combustion pattern of the BFG flow rate, T31-Ts is 30 [min], T32-T31 is 15 [min], and Te-Ts is 71 [min]. To do.

Next, the target BFG flow rate derivation unit 1604 changes the value of the first BFG flow pattern in the first time zone, and the difference between the first time zone and the second time zone of the first BFG flow pattern. Is changed to ΔB1. Further, the target BFG flow rate derivation unit 1604 changes the first switching time T31 of the first BFG flow rate pattern to the first switching time T31 of the optimum combustion pattern of the BFG flow rate. Further, the target BFG flow rate derivation unit 1604 changes the difference between the first time zone and the second time zone to ΔB1 and then changes the difference between the second time zone and the third time zone of the first BFG flow rate pattern. To ΔB2. Further, the target BFG flow rate derivation unit 1604 changes the second switching time T32 of the first BFG flow rate pattern to the second switching time T32 of the optimum combustion pattern of the BFG flow rate. In the following description, the first BFG flow rate pattern changed as described above will be referred to as a second BFG flow rate pattern, if necessary.

FIG. 21 (a) is a diagram showing an example of the second BFG flow rate pattern. In the example shown in FIG. 20B, the value B21 of the first BFG flow rate pattern in the first time zone is 130 [kNm ³ / hr]. Therefore, as shown in FIG. 21A, the value B42 of the second BFG flow rate pattern in the second time zone becomes 138 [kNm ³ / hr] (= 130 + 8). Further, the first switching time T31 of the optimum combustion pattern of the BFG flow rate shown in FIG. 20C is a time when 30 [min] has elapsed from the combustion start time Ts. Therefore, as shown in FIG. 21A, the first switching time T31 of the second BFG flow rate pattern is the time when 30 [min] has elapsed from the combustion start time Ts. The value B42 of the second BFG flow rate pattern in the second time zone is 138 [kNm ³ / hr]. ΔB2 is 2 [kNm ³ / hr]. Therefore, as shown in FIG. 21A, the value B43 of the second BFG flow rate pattern in the third time zone becomes 140 [kNm ³ / hr] (= 138 + 2). Further, the second switching time T32 of the optimum combustion pattern of the BFG flow rate shown in FIG. 20C is a time when 20 [min] has elapsed from the first switching time T31. Therefore, as shown in FIG. 21A, the second switching time T32 of the second BFG flow rate pattern is the time when 20 [min] has elapsed from the first switching time T31. With the second BFG flow rate pattern, the previous target combustion pattern of the BFG flow rate can be changed according to the input heat amount ratio (= Qin-1 / Qin-0).

In the second BFG flow rate pattern shown in FIG. 21 (a), the value of the BFG flow rate and the switching times T31 and T32 are changed with respect to the first BFG flow rate pattern shown in FIG. 20 (b). Therefore, in the second BFG flow rate pattern, the optimum heat input Qin-1 cannot be maintained next time. Therefore, the target BFG flow rate derivation unit 1604 changes the second BFG flow rate pattern so that the optimum input heat amount Qin-1 can be maintained as much as possible next time.

First, the target BFG flow rate derivation unit 1604 derives the total BFG flow rate of the first BFG flow pattern shown in FIG. 20 (b). That is, the target BFG flow rate derivation unit 1604 derives the area S1 of the first BFG flow rate pattern shown in FIG. 20 (b). In the above example, the area S1 of the first BFG flow pattern is 9420 [Nm ³ ] (= 130 × 25 + 133 × 20 + 135 × (71-25-20)). The area refers to the integrated value of the values of the BFG flow rate at each time. This also applies to the following description.

Next, the target BFG flow rate derivation unit 1604 derives the total BFG flow rate of the second BFG flow pattern shown in FIG. 21 (a). That is, the target BFG flow rate derivation unit 1604 derives the area S2 of the second BFG flow rate pattern shown in FIG. 21 (a). In the above example, the area S2 of the second BFG flow pattern is 9610 [Nm ³ ] (= 130 × 30 + 138 × 15 + 140 × (71-30-15)).

Next, the target BFG flow rate derivation unit 1604 has the area S1 of the BFG flow rate of the first BFG flow pattern shown in FIG. 20 (b) and the second BFG flow rate area S1 shown in FIG. 21 (a) according to the following equation (50). The difference ΔS from the area S2 of the BFG flow rate pattern is derived.
ΔS = S1-S2 ... (50)
In the above-described example, the difference ΔS between the area S1 of the first BFG flow rate pattern and the area S2 of the second BFG flow rate pattern is −190 [N ・ m ³ ] (= 9420-9610).

Next, the target BFG flow rate derivation unit 1604 derives the gas flow rate adjustment value ΔG by the following equation (51). That is, the target BFG flow rate derivation unit 1604 sets the difference ΔS between the area S1 of the first BFG flow rate pattern and the area S2 of the second BFG flow rate pattern as one combustion period (combustion start time Ts to combustion end time). The period until Te = Te-Ts).
ΔG = ΔS ÷ (Te−Ts) ・ ・ ・ (51)
In the above-mentioned example, the gas flow rate adjustment value ΔG is -3 [kNm ³ / hr] (= −190 ÷ 71).

By adding the gas flow rate adjustment value ΔG to the value of the second BFG flow rate pattern, the optimum heat input amount Qin-1 can be maintained as much as possible next time. FIG. 21B is a diagram showing a gas flow rate adjustment value ΔG superimposed on the second BFG flow rate pattern. In FIG. 21B, the value of the gas flow rate adjustment value ΔG is set to a positive value (= 3) in order to show the difference between the second BFG flow rate pattern and the gas flow rate adjustment value ΔG in an easy-to-understand manner.
Therefore, the target BFG flow rate derivation unit 1604 has a value B51 obtained by adding the value of the second BFG flow rate pattern and the gas flow rate adjustment value ΔG as in the following equations (52a), (52b), and (52c). , B52, B53 are derived. The BFG flow rate pattern derived in this way becomes the target combustion pattern of the BFG flow rate.
B51 = B21 + ΔG ... (52a)
B52 = B42 + ΔG ... (52b)
B51 = B43 + ΔG ... (52c)

FIG. 21 (c) is a diagram showing an example of a target combustion pattern of the BFG flow rate. As shown in FIG. 21 (c), the value B51 of the target combustion pattern of the BFG flow rate in the first time zone is 127 [kNm ³ / hr] (= 130-3). The value B52 of the target combustion pattern of the BFG flow rate in the second time zone is 135 [kNm ³ / hr] (= 138-3). The value B53 of the target combustion pattern of the BFG flow rate in the third time zone is 137 [kNm ³ / hr] (= 140-3). The switching times T31 and T32 of the target combustion pattern of the BFG flow rate are the same as the switching times T31 and T32 of the second BFG flow rate pattern. That is, as shown in FIG. 21C, in the target combustion pattern of the BFG flow rate, T31-Ts is 30 [min] and T32-T31 is 15 [min]. By deriving the target combustion pattern of the BFG flow rate as described above, the BFG flow rate pattern that maintains the optimum combustion pattern of the BFG flow rate (differences ΔB1 and ΔB2) and the next optimum input heat amount Qin-1 as much as possible is BFG. It can be the target combustion pattern of the flow rate.

Next, the target BFG flow rate derivation unit 1604 determines whether or not the target combustion pattern of the BFG flow rate derived by the equations (52a) to (52c) deviates from the upper and lower limit values of the BFG flow rate. The upper and lower limits of the BFG flow rate are set in advance by the operator in the hot air furnace control calculation device 301 using the input device 312 from the viewpoint of whether or not the hot air furnaces 100a to 100d are properly operated.

When the target combustion pattern of the BFG flow rate derived by the equations (52a) to (52c) does not deviate from the upper and lower limit values of the BFG flow rate, the target BFG flow rate derivation unit 1604 sets the target combustion pattern of the BFG flow rate. , The target combustion pattern of the BFG flow rate output to the flow rate controllers 304a to 304b and the like is determined.
The target BFG flow rate derivation unit 1604 changes the target combustion pattern of the BFG flow rate when the target combustion pattern of the BFG flow rate derived by the equations (52a) to (52c) is out of the range of the upper and lower limits of the BFG flow rate. .. FIG. 22 is a diagram illustrating an example of a method of changing the target combustion pattern of the BFG flow rate. FIG. 22A is a diagram showing an example of a target combustion pattern of the BFG flow rate before the change. The BFG flow rate pattern before the change is the target combustion pattern of the BFG flow rate derived by the equations (52a) to (52c). FIG. 22B is a diagram showing an example of a process of changing the target combustion pattern of the BFG flow rate. FIG. 22 (c) is a diagram showing an example of the target combustion pattern of the BFG flow rate after the change.

The target BFG flow rate derivation unit 1604 determines whether or not the target combustion pattern of the BFG flow rate before the change has a value exceeding the upper limit value or a value lower than the lower limit value for each of the first to third time zones. As a result of this determination, if the target BFG flow rate derivation unit 1604 has a value exceeding the upper limit value in at least one time zone, the target BFG flow rate derivation unit 1604 changes the value of the BFG flow rate of the portion exceeding the upper limit value to the upper limit value. Further, when the target BFG flow rate derivation unit 1604 has a value lower than the lower limit value in at least one time zone, the target BFG flow rate derivation unit 1604 changes the value of the BFG flow rate in the portion below the lower limit value to the lower limit value. In the example shown in FIG. 22 (a), the target combustion pattern of the BFG flow rate before the change is below the lower limit value B5 min in the first time zone. Further, the target combustion pattern of the BFG flow rate before the change exceeds the upper limit value B5max in the third time zone. Therefore, the target BFG flow rate derivation unit 1604 changes the value B51 of the target combustion pattern of the BFG flow rate in the first time zone to the lower limit value Bmin. Further, the target BFG flow rate derivation unit 1604 changes the value B53 of the target combustion pattern of the BFG flow rate in the third time zone to the upper limit value Bmax. In the following description, the target combustion pattern of the BFG flow rate changed in this way is referred to as a third BFG flow rate pattern, if necessary.

FIG. 22B is a diagram showing an example of a third BFG flow rate pattern. Here, it is assumed that the value B51 of the target combustion pattern of the BFG flow rate in the first time zone is 127 [kNm ³ / hr]. Further, it is assumed that the lower limit value B5 min is 130 [kNm ³ / hr]. Further, it is assumed that the value B52 of the target combustion pattern of the BFG flow rate in the second time zone is 135 [kNm ³ / hr]. Further, it is assumed that the value B53 of the target combustion pattern of the BFG flow rate in the third time zone is 137 [kNm ³ / hr]. Further, it is assumed that the upper limit value is 136 [kNm ³ / hr]. In this case, as shown in FIG. 22B, the target BFG flow rate derivation unit 1604 sets the value B51 of the target combustion pattern of the BFG flow rate in the first time zone from 127 [kNm ³ / hr] to 130 [kNm ³ /]. change to hr]. Further, as shown in FIG. 22B, the target BFG flow rate derivation unit 1604 sets the value B53 of the target combustion pattern of the BFG flow rate in the third time zone from 137 [kNm ³ / hr] to 136 [kNm ³ / hr]. ] To change.

Next, the target BFG flow rate derivation unit 1604 derives the sum of the BFG flow rates of the portion exceeding the upper limit value B5max and the sum of the BFG flow rates of the portion below the lower limit value Bmin in the target combustion pattern of the BFG flow rate before the change. .. In the example shown in FIG. 22 (b), the target BFG flow rate derivation unit 1604 has a target combustion pattern value B51 and a lower limit value B5 min of the BFG flow rate in the first time zone (= T31-Ts) and the first time zone. The value multiplied by the difference from (B51-B5min) is derived as the sum of the BFG flow rates of the portion exceeding the upper limit value B5max (see region 2201). Further, the target BFG flow rate derivation unit 1604 is the difference between the third time zone (= Te-T32) and the target combustion pattern value B53 and the upper limit value B5max of the BFG flow rate in the third time zone (B53-B5max). The value multiplied by is derived as the sum of the BFG flow rates of the portion exceeding the upper limit value B5max (see region 2202). In the above-described example, the target BFG flow rate derivation unit 1604 derives −90 [N ・ m ³ ] (= (127-130) × 30) as the sum of the BFG flow rates of the portion below the lower limit value Bmin. Further, the target BFG flow rate derivation unit 1604 derives 30 [Nm ³ ] (= (137-136) × 30) as the sum of the BFG flow rates of the portion exceeding the upper limit value B5max.

Next, the target BFG flow rate derivation unit 1604 derives a value obtained by dividing the total BFG flow rate of the portion below the lower limit value Bmin by a value obtained by subtracting the time in the time zone not out of the upper and lower limit values. In the following description, this value will be referred to as a first adjusted flow rate, if necessary. In the example shown in FIG. 22B, the time zone that does not deviate from the upper and lower limit values is the second time zone. The target BFG flow rate derivation unit 1604 derives −6 [kNm ³ / hr] (= −90 ÷ 15) as the first adjustment flow rate. Further, the target BFG flow rate derivation unit 1604 derives a value obtained by dividing the total BFG flow rate of the portion exceeding the upper limit value B5max by a value obtained by subtracting the time in the time zone not exceeding the upper and lower limit values. In the following description, this value will be referred to as a second adjusted flow rate, if necessary. In the example shown in FIG. 22B, the target BFG flow rate derivation unit 1604 derives 2 [kNm ³ / hr] (= 30/15) as the second adjustment flow rate.

Next, the target BFG flow rate derivation unit 1604 derives a value obtained by adding the first adjusted flow rate and the second adjusted flow rate. In the following description, this value will be referred to as the adjusted flow rate as necessary. The adjusted flow rate is a BFG flow rate that needs to be adjusted with respect to the target combustion pattern of the BFG flow rate in the time zone that does not deviate from the upper and lower limit values in order to maintain the optimum heat input amount Qin-1 as much as possible next time. In the above example, the target BFG flow rate derivation unit 1604 derives -4 [kNm ³ / hr] (= −6 + 2) as the adjusted flow rate.
Next, the target BFG flow rate derivation unit 1604 adds the adjusted flow rate to the BFG flow rate value in the time zone in which the BFG flow rate value is not changed in the target combustion pattern of the BFG flow rate before the change. In the above-mentioned example, the time zone in which the value of the BFG flow rate is not changed is the second time zone. Therefore, the target BFG flow rate derivation unit 1604 adds the adjusted flow rate (= -4) to the value B52 (= 135) of the target combustion pattern of the BFG flow rate in the second time zone, and adds the second to the value B62 (= 131). The target combustion pattern of the BFG flow rate in the time zone of is changed. FIG. 22 (c) is a target combustion pattern of the changed BFG flow rate derived as described above. The target BFG flow rate derivation unit 1604 determines the changed target combustion pattern of the BFG flow rate shown in FIG. 22C as the target combustion pattern of the dome temperature output to the flow rate controllers 304a to 304b and the like. By doing so, the area of the target combustion pattern of the BFG flow rate can be made the same before and after the change. Therefore, even if the target combustion pattern of the BFG flow rate derived by the equations (52a) to (52c) is out of the range of the upper and lower limits of the BFG flow rate, the optimum heat input Qin-1 for the next time is maintained as much as possible. be able to.

((Target combustion pattern output unit 1605))
The target combustion pattern output unit 1605 outputs the target combustion pattern to the flow rate controllers 304a to 304b and the like. The target combustion patterns are the target combustion pattern of the dome temperature determined to be output to the flow rate controllers 304a to 304b and the like by the target dome temperature derivation unit 1601 and the flow rate controllers 304a to 304b and the like by the target C / B ratio derivation unit 1603. The target combustion pattern of the C / B ratio determined to be output and the target combustion pattern of the BFG flow rate determined to be output to the flow rate controllers 304a to 304b by the target BFG flow rate deriving unit 1604 are included.

[Operation flowchart]
Next, an example of the operation of the target combustion pattern deriving unit 503 will be described with reference to the flowcharts of FIGS. 23A to 23C.
In step S2301, the target combustion pattern deriving unit 503 determines whether or not it is the timing to start the process. In the present embodiment, the target combustion pattern derivation unit 503 is the timing to start the process at a predetermined time within the switching periods 401a, 401c, 401e before the start of the combustion periods 402a, 402b, 402c of each cycle. Is determined. This determination is made every 100a to 100d of the hot air furnace. As a result of this determination, when it is time to start the process, the process proceeds to step S2302.

In step S2302, the target combustion pattern derivation unit 503 acquires the optimum input heat amount for all the hot air furnaces 100a to 100d from the input heat amount acquisition unit 501. The optimum heat input amount includes the next optimum heat input amount Qin-1 and the previous optimum heat input amount Qin-0. The next optimum heat input Qin-1 is the optimum heat input in the combustion period next to the switching period to which the timing determined to start the process in step S2301 belongs. The previous optimum heat input Qin-0 is the optimum heat input in the combustion period immediately before the next combustion period.

Next, in step S2303, the target combustion pattern deriving unit 503 acquires the latest optimum combustion patterns for all the hot air furnaces 100a to 100d from the combustion pattern acquisition unit 502. The optimum combustion pattern includes an optimum combustion pattern of the dome temperature, an optimum combustion pattern of the BFG flow rate, and an optimum combustion pattern of the C / B ratio.

Next, in step S2304, the target dome temperature derivation unit 1601 derives the weighted average value DTave of the previous target combustion pattern of the dome temperature by the equation (44).
Next, in step S2305, the target dome temperature derivation unit 1601 derives the weighted average value DMave of the optimum combustion pattern of the dome temperature by the equation (45).
Next, in step S2306, the target dome temperature derivation unit 1601 sets the differences ΔTD1, ΔTD2, and ΔTD3 between the optimum combustion pattern value of the dome temperature and the weighted average value DMave according to the equations (46a) to (46c). Derived for each of the first to third time zones.

Next, in step S2307, the target dome temperature derivation unit 1601 is dome in the first time zone, the second time zone, and the third time zone according to the equations (47a), (47b), and (47c). The target combustion patterns D31, D32, and D33 of the temperature are derived.
Next, in step S2308, the target dome temperature derivation unit 1601 determines whether or not the target combustion pattern of the dome temperature derived in step S2307 deviates from the upper and lower limit values of the dome temperature. As a result of this determination, if the target combustion pattern of the dome temperature is out of the range of the upper and lower limits of the dome temperature, the process proceeds to step S2309.

Proceeding to step S2309, the target dome temperature derivation unit 1601 changes the target combustion pattern of the dome temperature as described with reference to FIGS. 18 (a) and 18 (b). Then, the process proceeds to step S2310. Proceeding to step S2310, the target dome temperature derivation unit 1601 stores the target combustion pattern of the dome temperature changed in step S2309. Then, the process proceeds to step S2311 of FIG. 23B.
On the other hand, in step S2308, if the target combustion pattern of the dome temperature does not deviate from the upper and lower limit values of the dome temperature, the process skips step S2308 and proceeds to step S2309. Proceeding to step S2309, the target dome temperature derivation unit 1601 stores the target combustion pattern of the dome temperature derived in step S2307. Then, the process proceeds to step S2311 of FIG. 23B.

Proceeding to step S2111, the input heat amount ratio derivation unit 1602 derives the input heat amount ratio (= Qin-1 / Qin-0).
Next, in step S2312, the target C / B ratio derivation unit 1603 derives the target combustion pattern C12 of the C / B ratio by the equation (48).
Next, in step S2313, the target C / B ratio derivation unit 1603 determines whether or not the target combustion pattern of the C / B ratio derived in step S2312 is out of the range of the upper and lower limit values of the C / B ratio. .. As a result of this determination, if the target combustion pattern of the C / B ratio is out of the range of the upper and lower limits of the C / B ratio, the process proceeds to step S2314.

Proceeding to step S2314, the target C / B ratio derivation unit 1603 changes the target combustion pattern of the C / B ratio. Specifically, when the target combustion pattern of the C / B ratio before the change exceeds the upper limit of the C / B ratio, the target C / B ratio derivation unit 1603 determines the target combustion pattern of the C / B ratio before the change. Change the value to the upper limit. Further, when the target combustion pattern of the C / B ratio before the change is lower than the lower limit of the C / B ratio, the target C / B ratio derivation unit 1603 is the value of the target combustion pattern of the C / B ratio before the change. Is changed to the lower limit value. Then, the process proceeds to step S2315. Proceeding to step S2315, the target C / B ratio derivation unit 1603 stores the target combustion pattern of the C / B ratio changed in step S2314. Then, the process proceeds to step S2316 of FIG. 23C.
On the other hand, in step S2313, if the target combustion pattern of the C / B ratio does not deviate from the range of the upper and lower limit values of the C / B ratio, the process skips step S2314 and proceeds to step S2315. Proceeding to step S2315, the target C / B ratio derivation unit 1603 stores the target combustion pattern of the C / B ratio derived in step S2312. Then, the process proceeds to step S2316 of FIG. 23C.

Proceeding to step S2316, the target BFG flow rate deriving unit 1604 calculates the equations (49a) to (49c) to derive the first BFG flow rate pattern.
Next, in step S2317, the target BFG flow rate derivation unit 1604 derives the differences ΔB1 and ΔB2 of the optimum combustion patterns of the BFG flow rates in the two time zones adjacent to each other (see FIG. 20C).

Next, in step S2318, the target BFG flow rate derivation unit 1604 derives the second BFG flow rate pattern (see FIG. 21A). For the second BFG flow rate pattern, the amount of change at each switching time T31 and T32 of the first BFG flow rate pattern was derived in step S2317 without changing the value of the first BFG flow rate pattern in the first time zone. It is changed to ΔB1 and ΔB2. Further, in the second BFG flow rate pattern, the switching times T31 and T32 of the first BFG flow rate pattern are changed to the switching times T31 and T32 of the optimum combustion pattern of the BFG flow rate.

Next, in step S2319, the target BFG flow rate derivation unit 1604 determines the difference ΔS between the area S1 of the first BFG flow rate pattern derived in step S2316 and the area S2 of the second BFG flow rate pattern derived in step S2317. Derivation (see equation (50)). Then, the target BFG flow rate derivation unit 1604 performs the calculation of the equation (51) to derive the gas flow rate adjustment value ΔG.
Next, in step S2320, the target BFG flow rate derivation unit 1604 calculates the equations (52a) to (52c) to derive the target combustion pattern of the BFG flow rate.

Next, in step S2321, the target BFG flow rate derivation unit 1604 determines whether or not the target combustion pattern of the BFG flow rate derived in step S2320 deviates from the range of the upper and lower limit values of the BFG flow rate. As a result of this determination, if the target combustion pattern of the BFG flow rate is out of the range of the upper and lower limit values of the BFG flow rate, the process proceeds to step S2322.
Proceeding to step S2322, the target BFG flow rate derivation unit 1604 changes the target combustion pattern of the BFG flow rate as described with reference to FIGS. 22 (a) to 22 (c).
Next, in step S2323, the target BFG flow rate derivation unit 1604 stores the target combustion pattern of the BFG flow rate changed in step S2322. Then, the process proceeds to step S2324.
On the other hand, in step S2321, if the target combustion pattern of the BFG flow rate does not deviate from the range of the upper and lower limit values of the BFG flow rate, the process skips step S2322 and proceeds to step S2323. Proceeding to step S2323, the target BFG flow rate derivation unit 1604 stores the target combustion pattern of the BFG flow rate derived in step S2320. Then, the process proceeds to step S2324.

Proceeding to step S2324, the target combustion pattern output unit 1605 outputs the target combustion pattern to the flow rate controllers 304a to 304b and the like. The target combustion patterns are the latest dome temperature target combustion pattern stored in step S2310, the latest C / B ratio target combustion pattern stored in step S2315, and the latest BFG flow rate stored in step S2323. Including the target combustion pattern. Then, the processing according to the flowcharts of FIGS. 23A to 23C is completed. The target combustion pattern output in step S2324 will be the previous target combustion pattern at the next execution of the flowcharts of FIGS. 23A to 23C.

[Summary]
In the embodiment of the present invention described above, the target combustion pattern derivation unit 503 has the next optimum input heat amount Qin-1 and the previous optimum input heat amount Qin-0, the optimum combustion pattern of the BFG flow rate, and the target of the previous BFG flow rate. Based on the combustion pattern, the target combustion pattern of the BFG flow rate in the next combustion period is derived. Further, the target combustion pattern derivation unit 503 determines the C / in the next combustion period based on the next optimum input heat amount Qin-1 and the previous optimum input heat amount Qin-0 and the previous optimum combustion pattern of the C / B ratio. The target combustion pattern of the B ratio is derived. Further, the target combustion pattern derivation unit 503 derives the target combustion pattern of the dome temperature in the next combustion period based on the optimum combustion pattern of the dome temperature and the target combustion pattern of the previous dome temperature. Therefore, the target values of the BFG flow rate, the C / B ratio, and the dome temperature in the next combustion period can be appropriately set.

Further, in the target combustion pattern deriving unit 503, the target combustion pattern of the BFG flow rate, the target combustion pattern of the C / B ratio, and the target combustion pattern of the dome temperature derived as described above are set to the upper and lower limit values D1max, D1min, and D2max. , D2min, D3max, and D3min, and the target combustion pattern of the BFG flow rate, the target combustion pattern of the C / B ratio, and the target combustion pattern of the dome temperature are changed. Therefore, it is possible to suppress the setting of a target value that prevents the hot air furnaces 100a to 100d from being properly operated. At this time, the target combustion pattern derivation unit 503 changes the target combustion pattern of the BFG flow rate so that the input heat amount does not change before and after the change. Therefore, the control device 300 can supply the BFG to the combustion burners 108 of the hot blast furnaces 100a to 100d so that the optimum input heat amount Qin-1 can be maintained as much as possible in the next combustion period. Further, the target combustion pattern derivation unit 503 changes the target combustion pattern of the dome temperature before and after the change so that the weighted average value DTave of the previous target combustion pattern of the dome temperature does not change. Therefore, in the next combustion period, the control device 300 can suppress a large fluctuation in the dome temperature for each combustion period.

[Modification example]
In this embodiment, the case where the C / B ratio is used has been described as an example. However, it is not always necessary to do this. For example, the COG flow rate may be used instead of the C / B ratio. Moreover, you may use only COG as a combustion gas without using BFG. In this case, the C / B ratio becomes unnecessary. Further, in this case, the optimum combustion pattern of COG and the target combustion pattern are derived in the same manner as, for example, the BFG flow rate.

Further, in the present embodiment, the case where the flow rate of BFG and the flow rate of COG are controlled independently has been described as an example. However, it is not always necessary to do this. For example, a mixed gas containing BFG and COG may be used as the combustion gas. In this case, the optimum combustion pattern of the mixed gas and the target combustion pattern are derived in the same manner as, for example, the BFG flow rate. In this case, for example, the flow rate of combustion air is used instead of the C / B ratio. The target combustion pattern of the flow rate of combustion air has only the initial target value, for example, as in the C / B ratio. After that, by feedback control using the PID controller, the flow rate of combustion air (opening of the air butterfly valve 128) is feedback controlled so that the dome temperature measured by the dome thermometer 135 becomes the target combustion pattern of the dome temperature. To do.

Further, the case where the optimum heat input Qin-0 of the previous time and the target combustion pattern of the previous time are used has been described as an example. However, it is not always necessary to do this. For example, instead of the previous optimum heat input Qin-0, the actual value of the heat input during the previous combustion period may be used. Further, instead of the previous target combustion pattern, the actual value of the combustion pattern in the previous combustion period may be used.

Further, in the present embodiment, the case where the change amounts ΔU11 and ΔU12 of the dome temperature U1, the change amounts ΔU21 of the C / B ratio, and the change amounts ΔU31 and ΔU32 of the BFG flow rate U3 are taken as individuals has been described as an example. However, it is not always necessary to do this. For example, ΔU11, ΔU12, ΔU21, ΔU31, and ΔU32 may be described in Patent Document 5. Specifically, ΔU11 is a value corresponding to the dome temperature before the target value is changed, and is a value in the range from the lower limit value to the upper limit value of the adjustable range of the dome temperature. ΔU12 is a value corresponding to the dome temperature after the target value is changed, and is a value in the range from the lower limit value to the upper limit value of the adjustable range of the dome temperature. ΔU21 is a value corresponding to the C / B ratio before the target value is changed, and is a value in the range from the lower limit value to the upper limit value of the adjustable range of the C / B ratio. Further, as the individual ΔU22, a value in the range from the lower limit value to the upper limit value of the adjustable range of the C / B ratio, which is a value corresponding to the C / B ratio after the target value is changed, is used. ΔU31 is a value corresponding to the BFG flow rate before the target value is changed, and is a value in the range from the lower limit value to the upper limit value of the adjustable range. ΔU32 is a value corresponding to the BFG flow rate after the target value is changed, and is a value in the range from the lower limit value to the upper limit value of the adjustable range. In the above case, since the target combustion pattern of the dome temperature does not deviate from the range of the upper and lower limit values of the dome temperature, the processing of steps S2308 and S2309 becomes unnecessary. Further, since the target combustion pattern of the C / B ratio does not deviate from the range of the upper and lower limit values of the C / B ratio, the processing of steps S2313 and S2314 becomes unnecessary. Further, since the target combustion pattern of the BFG flow rate does not deviate from the range of the upper and lower limit values of the BFG flow rate, the process of step S2321 becomes unnecessary.

Further, in the present embodiment, when there is a time zone in which the upper limit value D3max is exceeded and a time zone in which the lower limit value D3min is lower, the target dome temperature derivation unit 1601 sets the value of the target combustion pattern of the dome temperature before the change in the time zone. The case of changing to the upper limit value D3max and the lower limit value D3min has been described as an example. In this way, the weighted average value of the changed dome temperature target combustion pattern cannot be matched with the weighted average value DTave of the previous target combustion pattern of the dome temperature. Therefore, the weighted average value of the target combustion pattern of the changed dome temperature may be matched with the weighted average value DTave of the previous target combustion pattern of the dome temperature.

An example of the processing of the target dome temperature derivation unit 1601 in this case will be described below. This process is a process performed in place of the process of step S2309 of FIG. 23A. FIG. 24 is a diagram illustrating a modified example of the method of changing the target combustion pattern of the dome temperature. FIG. 24A is a diagram showing an example of a target combustion pattern of the dome temperature before the change. FIG. 24B is a diagram illustrating an example of a target combustion pattern of the dome temperature before the change, a target combustion pattern during the change, and a target combustion pattern after the change.

In order to match the weighted average value of the target combustion pattern of the dome temperature after the change with the weighted average value DTave of the previous target combustion pattern of the dome temperature, the target combustion pattern of the dome temperature after the change and the target combustion pattern before the change Therefore, the ratio (= A: B: C) shown in FIG. 24 (a) needs to be maintained. Here, A is the difference between the target combustion pattern D31 of the dome temperature in the first time zone and the weighted average value DTave of the previous target combustion pattern of the dome temperature. B is the difference between the target combustion pattern D32 of the dome temperature in the second time zone and the weighted average value DTave of the previous target combustion pattern of the dome temperature. C is the difference between the target combustion pattern D33 of the dome temperature in the third time zone and the weighted average value DTave of the previous target combustion pattern of the dome temperature.

Therefore, when the target combustion pattern of the dome temperature before the change exceeds the upper limit value D3max, the target dome temperature derivation unit 1601 changes the target combustion pattern of the dome temperature before the change to the upper limit value D3max. Further, when the target combustion pattern of the dome temperature before the change is lower than the lower limit value D3min, the target dome temperature derivation unit 1601 changes the target combustion pattern of the dome temperature before the change to the lower limit value D3min. In the example shown in FIG. 24B, the target dome temperature derivation unit 1601 changes the target combustion pattern of the dome temperature in the first time zone to the upper limit value D3max. Further, the target combustion pattern of the dome temperature in the third time zone is changed to the lower limit value D3min.

When the target combustion pattern of the BFG flow rate before the change deviates from the upper and lower limit values D3max and D3min in a plurality of time zones, the target dome temperature derivation unit 1601 derives the reduction rate rate in the plurality of time zones. The reduction rate rate is a value obtained by dividing the absolute value of the target deviation after the change by the absolute value of the target deviation before the change (= | target deviation after the change | ÷ | target deviation before the change |). The target deviation before the change is the difference between the target combustion pattern of the dome temperature before the change and the weighted average value DTave of the previous target combustion pattern of the dome temperature. The changed target deviation is the difference between the upper limit value D3max or the lower limit value D3min and the weighted average value DTave of the previous target combustion pattern of the dome temperature. When the target combustion pattern of the dome temperature before the change exceeds the upper limit value D3max, the upper limit value D3max is used when deriving the target deviation after the change. On the other hand, when the target combustion pattern of the dome temperature before the change is lower than the lower limit value D3min, the lower limit value D3min is used when deriving the target deviation after the change.

In the example shown in FIG. 24 (b), the target dome temperature derivation unit 1601 has a reduction rate rate (= | D3max-DTave | ÷ | D31-DTave |) in the first time zone and reduction in the third time zone. The rate rate (= | D3min-DTave | ÷ | D33-DTave |) is derived.

When the target combustion pattern of the dome temperature in the time zone when the reduction rate rate is the minimum among the target combustion patterns of the dome temperature before the change exceeds the upper limit value D3max, the target dome temperature derivation unit 1601 determines the dome temperature in the time zone. The target combustion pattern of is changed to the upper limit value D3max. Further, when the target combustion pattern of the dome temperature in the time zone where the reduction rate rate is the minimum among the target combustion patterns of the dome temperature before the change is less than the lower limit value D3min, the target dome temperature derivation unit 1601 is in the time zone. The target combustion pattern of the dome temperature is changed to the lower limit value D3min.

In the example shown in FIG. 24 (b), the target dome temperature derivation unit 1601 selects a time zone having a smaller reduction rate rate among the first time zone and the third time zone. Here, it is assumed that the time zone having the smaller reduction rate rate among the first time zone and the third time zone is the first time zone. In the following description, the minimum reduction rate rate is expressed as rate_m.

Next, the target dome temperature derivation unit 1601 determines the value of the target combustion pattern of the changed dome temperature in the first time zone to the upper limit value D3max.

After doing the above, the target dome temperature derivation unit 1601 maintains the ratio (A: B: C) between the target combustion pattern of the changed dome temperature and the target combustion pattern before the change. , Change the target combustion pattern of the dome temperature at other times.
In the example shown in FIG. 24 (a), the target dome temperature derivation unit 1601 sets the value of the target combustion pattern of the changed dome temperature in the second time zone and the third time zone other than the first time zone. It is changed by using the reduction rate rate_m in the first time zone. Specifically, the target dome temperature derivation unit 1601 derives the value D34 of the target combustion pattern of the changed dome temperature in the second time zone by the following equation (46). Further, the target dome temperature derivation unit 1601 derives the value D35 of the target combustion pattern of the changed dome temperature in the third time zone by the following equation (47).
D34 = DTave + (D32-DTave) x rate_m ... (46)
D35 = DTave + (D33-DTave) x rate_m ... (47)

In addition, in the embodiment of the present invention described above, if the number of hot air furnaces 100 is one or more, it does not necessarily have to be four. Further, the hot air furnace control calculation device 301 and the input / output device 302 may be arranged outside the steelworks. In this case, the input / output device 302 inputs the information of the measured value in the measuring instrument in the steelworks via the communication network. Further, the hot air furnace control calculation device 301 transmits, for example, a target combustion pattern of the BFG flow rate, a target combustion pattern of the dome temperature, and a target combustion pattern of the C / B ratio to the flow rate controllers 304a to 304d. , Through the communication network. Similarly, the hot air furnace control calculation device 301 transmits the target value of the hot air temperature to the temperature controller 305 via the communication network. The input / output device 302 may perform the above transmission.

Further, the embodiment of the present invention described above can be realized by executing a program by a computer. Further, a computer-readable recording medium on 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 non-volatile memory card, a ROM, or the like can be used.
In addition, the embodiments of the present invention described above are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. It is a thing. That is, the present invention can be implemented in various forms without departing from the technical idea or its main features.

[Relationship with claims]
An example of the correspondence between the description of the claim and the description of the embodiment will be described below. The description of the claims is not limited to the description of the embodiment, as described in the modified examples and the like.
The target combustion pattern derivation means corresponds to, for example, the target combustion pattern derivation unit 503.
The target value of the gas flow rate pattern in the next combustion period corresponds to, for example, the target combustion pattern of the BFG flow rate.
The input heat amount acquisition means corresponds to, for example, the input heat amount acquisition unit 501.
The calculated value of the amount of heat input to the hot blast furnace in the next combustion period corresponds to, for example, the next optimum amount of heat input Qin-1.
The combustion pattern acquisition means corresponds to, for example, the combustion pattern acquisition unit 502.
The calculated value of the gas flow rate pattern in the next combustion period corresponds to, for example, the optimum combustion pattern of the BFG flow rate.
The first switching period corresponds to, for example, the switching periods 401a, 401c, 401e.
The second switching period corresponds to, for example, switching periods 401b and 401d.
The amount of heat input to the hot air furnace during the previous combustion period corresponds to, for example, the previous optimum amount of heat input Qin-0.
The gas flow rate pattern of the previous combustion period corresponds to, for example, the previous target combustion pattern of the BFG flow rate.
The input heat amount ratio derivation means corresponds to, for example, the input heat amount ratio derivation unit 1602.
Target gas flow Ryoshirube detecting means corresponds to, for example, the target BFG flow rate deriving unit 1604.
The first pattern corresponds to, for example, the first BFG flow rate pattern (see FIG. 20B).
The second pattern corresponds, for example, to the second BFG flow pattern (see FIG. 21B).
The gas flow rate adjustment value corresponds to, for example, the gas flow rate adjustment value ΔG.
The target value of the dome temperature pattern in the next combustion period corresponds to, for example, the target combustion pattern of the dome temperature.
The calculated value of the dome temperature pattern in the next combustion period corresponds to, for example, the optimum combustion pattern of the dome temperature.
The dome temperature pattern of the previous combustion period corresponds to, for example, the previous target combustion pattern of the dome temperature.
The target value of the second gas flow rate pattern in the next combustion period corresponds to, for example, the target combustion pattern of the C / B ratio.
The second gas flow rate pattern of the previous combustion period corresponds to, for example, the previous target combustion pattern of the C / B ratio.
The ratio of the flow rate of the first gas to the flow rate of the second gas corresponds to, for example, the C / B ratio.

301: Hot air furnace control calculation device, 501: Input heat amount acquisition unit, 502: Combustion pattern acquisition unit, 503: Target combustion pattern derivation unit, 1601: Target dome temperature derivation unit, 1602: Input heat amount day derivation unit, 1603: Target C / B ratio derivation unit, 1604: target BFG flow rate derivation unit, 1605: target combustion pattern derivation unit

Claims (15)

A hot air furnace having a heat storage chamber and a combustion chamber for controlling the operation of a hot air furnace that operates with a period including a first switching period, a combustion period, a second switching period, and a blowing period as one cycle. It is a hot air furnace control calculation device that performs calculations.
In the first switching period, a target combustion pattern deriving means for deriving a target value of a gas flow rate pattern in the next combustion period, and
An input heat amount acquisition means for acquiring a calculated value of the input heat amount to the hot air furnace in the next combustion period, and
Combustion pattern acquisition means for acquiring the calculated value of the gas flow rate pattern in the next combustion period, and
Have,
The combustion period is a period in which heat storage bricks arranged in the heat storage chamber are heated by combustion gas to store heat.
The ventilation period is a period in which cold air is passed through the heat storage brick to generate hot air by heat exchange with the heat storage brick and supply it to the blast furnace.
The first switching period is a preparation period for shifting from the ventilation period to the combustion period.
The second switching period is a preparation period for shifting from the combustion period to the ventilation period.
The gas flow rate pattern shows the relationship between the flow rate of the first gas constituting the combustion gas and time.
The target combustion pattern deriving means is a calculated value of the amount of heat input to the hot blast furnace in the previous combustion period, the calculated value of the amount of heat input to the hot blast furnace in the next combustion period, and the gas flow rate pattern in the next combustion period. A hot blast furnace control calculation device, characterized in that a target value of a gas flow pattern in the next combustion period is derived based on a calculated value and the gas flow pattern in the previous combustion period. The hot blast furnace control calculation device according to claim 1, wherein the gas flow rate pattern in one combustion period has a plurality of time zones in which the value of the flow rate of the first gas is different. The target combustion pattern derivation means includes an input heat amount ratio derivation means for deriving the input heat amount ratio and
Further comprising a, a target gas flow Ryoshirube detecting means for deriving a target value of the gas flow pattern,
The heat input ratio is the ratio of the calculated value of the heat input to the hot air furnace during the next combustion period to the heat input to the hot air furnace during the previous combustion period.
The target gas flow Ryoshirube out portion may derive deriving a first pattern, the second pattern based on the calculated value of the gas flow pattern of the first pattern and the next combustion period it and, wherein the first pattern based on the second pattern, and to derive the gas flow rate adjustment value, change the second pattern based on the gas flow rate adjustment value of the next combustion and deriving a target value of the gas flow pattern of the period, the at least execution,
The first pattern is obtained by multiplying the gas flow rate pattern of the previous combustion period by the input heat amount ratio.
The second pattern is the difference in the flow rate values of the first gas in the first pattern, and the difference in the time zones adjacent to each other is the difference in the gas flow rate pattern in the next combustion period. The difference in the flow rate value of the first gas in the calculated value is the same as the difference in the time zones adjacent to each other, and the first pattern is changed.
The gas flow rate adjustment value is a value obtained from the integrated value of the values of the first gas flow rate at each time in the first pattern, and the value at each time of the first gas flow rate in the second pattern. The hot air furnace control calculation device according to claim 2, wherein the value obtained by subtracting the integrated value of is divided by the time of one combustion period. When the flow rate of the first gas in the target value of the gas flow rate pattern in the next combustion period is not within the upper and lower limit values, the target combustion pattern deriving means increases the flow rate of the first gas. The hot air furnace control calculation according to any one of claims 1 to 3, wherein the target value of the gas flow rate pattern in the next combustion period is changed so as to be within the range of the upper and lower limits. apparatus. In the target value of the gas flow rate pattern of the next combustion period before the change, the integrated value of the values of the flow rate of the first gas at each time and the gas of the next combustion period after the change. The hot air furnace control calculation device according to claim 4, wherein the integrated value of the values of the flow rate of the first gas at each time in the flow rate pattern is the same. The combustion pattern acquisition means further acquires the calculated value of the dome temperature pattern in the next combustion period.
The target combustion pattern deriving means further derives the target value of the dome temperature pattern in the next combustion period during the first switching period.
The dome temperature pattern shows the relationship between dome temperature and time.
The dome temperature is the temperature of the dome above the heat storage chamber.
The target combustion pattern deriving means targets the dome temperature pattern of the next combustion period based on the calculated value of the dome temperature pattern of the next combustion period and the dome temperature pattern of the previous combustion period. The hot air furnace control calculation device according to any one of claims 1 to 5, wherein a value is derived. The hot air furnace control calculation device according to claim 6, wherein the dome temperature pattern in one combustion period has a plurality of time zones in which the dome temperature values are different. A claim characterized in that the average value of the dome temperature in the dome temperature pattern of the previous combustion period is the same as the average value of the dome temperature in the target value of the dome temperature pattern of the next combustion period. Item 6. The hot air furnace control calculation device according to Item 6. When the dome temperature in the target value of the dome temperature pattern in the next combustion period is not within the upper and lower limit values, the target combustion pattern deriving means keeps the dome temperature within the upper and lower limit values. The hot air furnace control calculation device according to any one of claims 6 to 8, wherein the target value of the dome temperature in the next combustion period is changed so as to be such. The target combustion pattern derivation means further derives the target value of the second gas flow rate pattern of the next combustion period during the first switching period.
The second gas flow rate pattern is an initial target value in the combustion period of the flow rate of the second gas constituting the combustion gas or the ratio of the flow rate of the first gas to the flow rate of the second gas. Show,
The target combustion pattern deriving means includes a calculated value of the amount of heat input to the hot blast furnace during the previous combustion period, the calculated value of the amount of heat input to the hot blast furnace during the next combustion period, and the second gas during the previous combustion period. The hot air furnace control calculation device according to any one of claims 1 to 9, wherein a target value of the second gas flow pattern for the next combustion period is derived based on the flow pattern. When the flow rate of the second combustion gas at the target value of the second gas flow rate pattern in the next combustion period is not within the range of the upper and lower limits, the target combustion pattern deriving means performs the second combustion. The hot air furnace control according to claim 10, wherein the target value of the second gas flow rate pattern in the next combustion period is changed so that the gas flow rate is within the upper and lower limit values. Computational device. The first gas is BFG (Blast Furnace Gas).
The hot air oven control calculation device according to claim 10 or 11, wherein the second gas is COG (Coke Oven gas). The first gas according to any one of claims 1 to 9, wherein the first gas is a BFG (Blast Furnace Gas), a COG (Coke Oven gas), or a mixed gas containing BFG and COG. Blast furnace control calculator. A hot air furnace having a heat storage chamber and a combustion chamber for controlling the operation of a hot air furnace that operates with a period including a first switching period, a combustion period, a second switching period, and a blowing period as one cycle. It is a hot air furnace control calculation method that performs calculations.
In the first switching period, a target combustion pattern derivation step for deriving a target value of a gas flow rate pattern in the next combustion period, and
The input heat amount acquisition step for acquiring the calculated value of the input heat amount to the hot air furnace in the next combustion period, and
The combustion pattern acquisition process for acquiring the calculated value of the gas flow rate pattern for the next combustion period, and
Have,
The combustion period is a period in which heat storage bricks arranged in the heat storage chamber are heated by combustion gas to store heat.
The ventilation period is a period in which cold air is passed through the heat storage brick to generate hot air by heat exchange with the heat storage brick and supply it to the blast furnace.
The first switching period is a preparation period for shifting from the ventilation period to the combustion period.
The second switching period is a preparation period for shifting from the combustion period to the ventilation period.
The gas flow rate pattern shows the relationship between the flow rate of the first gas constituting the combustion gas and time.
In the target combustion pattern derivation step, the calculated values of the amount of heat input to the hot blast furnace in the previous combustion period, the calculated value of the amount of heat input to the hot blast furnace in the next combustion period, and the gas flow rate pattern in the next combustion period A hot blast furnace control calculation method, characterized in that a target value of a gas flow pattern in the next combustion period is derived based on a calculated value and the gas flow pattern in the previous combustion period. A program characterized in that a computer functions as each means of the hot air furnace control calculation device according to any one of claims 1 to 13.

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