JP5482249B2 - Plate temperature control device and plate temperature control method for continuous annealing furnace - Google Patents

Description

  The present invention relates to a plate temperature control device and a plate temperature control method in a continuous annealing furnace for metal strip, and more specifically, control so that the plate temperature of the metal strip passed through the continuous annealing furnace becomes a plate temperature target value. The present invention relates to a plate temperature control device and a plate temperature control method.

  For example, in a metal strip production line such as a steel plate, a continuous annealing furnace is a series of strips in which the ends and tips of a plurality of metal strips are connected in order and passed through a series of furnaces including a heating furnace. It is equipment for annealing and adjusting materials such as mechanical properties of the final product. The plate passing speed at which the strip is continuously passed through the furnace greatly affects the plate temperature and also the product quality. For this reason, in order to ensure product quality, it is required to continue operation stably.

  However, there may be a deceleration factor that must reduce the central line speed, which is the strip feed speed, in the continuous annealing furnace, such as incomplete connection between strips and operational troubles in the strip winder. is there. When such a deceleration factor of the central line speed occurs, the central line speed is reduced, while the looper amount of the inlet looper and the outlet looper installed before and after the continuous annealing furnace (the strips between the rolls of the looper). (Length) is increased / decreased to secure time until the deceleration factor is resolved, and the operation is continued. In other words, the looper functions as a buffer for the through plate. At this time, by reducing the central line speed, the in-furnace time of the strip in the passing plate becomes longer, so the strip is overheated, and the outlet side plate temperature on the outlet side of the heating furnace exceeds the prescribed upper limit value. May end up. Therefore, when a deceleration factor occurs, the plate temperature control sets the target furnace temperature of the heating furnace to be low so that the plate temperature (exit side plate temperature) at the outlet of the continuous annealing furnace falls within a specified range and passes through. I am doing so.

  After the deceleration factor is eliminated, the lower furnace temperature is raised to the original target furnace temperature. However, a certain amount of time is required until the furnace temperature is raised to the original target furnace temperature, and during this time, the central line speed cannot be returned to the central line speed during normal operation, resulting in decreased productivity. To do. Therefore, slowing down the central line speed should be avoided as much as possible.

  In order to solve such a problem, for example, Patent Document 1 predicts the deceleration start time of the central line speed and the required time until the deceleration factor is eliminated, and the required time is shorter than a preset set time. In such a case, a technique for preventing a decrease in the furnace temperature by setting the target plate temperature higher than the management target value within a range not exceeding the upper limit value of the management range is disclosed. Further, for example, in Patent Document 2, when a trouble occurs, the speed of the sheet passing is reduced, and the working temperature required for solving the trouble that has occurred is changed according to the time required to select the furnace temperature control mode. A technique is disclosed in which the fuel gas flow rate is set so as to maintain the furnace temperature or an arbitrary furnace temperature, the furnace temperature is controlled to be constant, and the outlet side plate temperature is monitored to be within a set tolerance. As a result, the strip feeding speed can be rapidly accelerated and the state before deceleration can be restored immediately after the deceleration factor is eliminated.

JP-A-9-176746 Japanese Patent Laid-Open No. 10-195546 Japanese Patent Laid-Open No. 01-184233 Japanese Patent Laid-Open No. 06-126333

  However, in Patent Document 1, if the selection of the set time that varies depending on the situation in relation to the center line speed, the furnace temperature, the fuel flow rate, the plate temperature, etc. is inappropriate, the fuel consumption rate will deteriorate. There was a problem. Also in Patent Document 2, since the set value of the fuel gas flow rate changes according to the work time required to solve the trouble, the fuel consumption rate may be deteriorated depending on the selection of the work time.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to optimize the central line speed and the optimum center line speed when a deceleration factor occurs for a strip that passes through a continuous annealing furnace. A new and improved continuous annealing furnace temperature control device that can set the target temperature flexibly and optimize the fuel consumption rate from the generation of the deceleration factor of the central line speed to the recovery of the central line speed. And providing a plate temperature control method.

In order to solve the above problems, according to an aspect of the present invention, there is provided a plate temperature control device that controls a plate temperature of a strip passed through a continuous annealing furnace so as to become a plate temperature target value. Such a plate temperature control device is a central temperature indicating the transition of the central line speed so that the amount of deceleration of the central line speed from the generation to the cancellation of the deceleration factor is minimized according to the deceleration factor of the central line speed for moving the strip. Based on the speed control unit that sets the line speed pattern, the center line speed pattern, the target plate temperature pattern that represents the transition of the target plate temperature target value, and the fuel flow rate pattern of the fuel supplied to the continuous annealing furnace The plate temperature pattern which estimates the plate temperature transition of the strip, and the estimated flow plate temperature is within the control range that can guarantee the product quality and the fuel flow pattern with the minimum fuel supply amount is the optimum fuel flow pattern and a control unit, a sheet temperature pattern control unit corresponds to the center line speed pattern, the target plate temperature setting multiple target plate temperature pattern representative of a transition of sheet temperature target value About the turn setting part, each target plate temperature pattern, the plate temperature estimation unit for estimating the plate temperature transition of the strip by changing the fuel flow rate pattern of the fuel supplied to the continuous annealing furnace, and each target plate temperature pattern, Based on the estimation result of the plate temperature transition by the plate temperature estimation unit, the local fuel flow pattern search unit which uses one fuel flow pattern among the fuel flow patterns following the plate temperature actual value as the local fuel flow pattern of the target plate temperature pattern Of the local fuel flow patterns of each target plate temperature pattern, the optimum fuel that determines the local fuel flow pattern with the estimated plate temperature within the control range and the minimum fuel supply amount as the optimum fuel flow pattern A flow rate pattern determination unit, and the target plate temperature pattern setting unit sets the plate temperature target value during the normal operation from the time when the deceleration factor occurs until the time when it is scheduled to be resolved. Higher than the value, and set to a temperature within the control range, characterized in Rukoto.

  According to the present invention, first, the central line speed pattern is set by the speed control unit so that the central line speed is not reduced as much as possible when a deceleration factor is generated. The plate temperature pattern control unit simulates the plate temperature response of the strip from the central line speed pattern set by the speed control unit, the target plate temperature pattern and the fuel flow rate pattern set in accordance with the central line speed pattern, and the deceleration factor The transition of the plate temperature from the occurrence of this to the elimination of the deceleration factor is obtained. Then, the plate temperature pattern control unit sets the fuel flow rate pattern in which the product quality is within the management range in which the product quality can be guaranteed from the estimated transition plate temperature and the fuel supply amount is minimum as the optimum fuel flow rate pattern. In this way, by determining the amount of fuel to be supplied to the continuous annealing furnace, it is possible to speed up the recovery to the normal operating state from the time when the deceleration factor is resolved, so the reduction in production volume can be suppressed, and the fuel consumption The amount can also be reduced.

  Further, the local fuel flow rate pattern search unit may set the fuel flow rate pattern that minimizes the difference between the plate temperature transition estimation result by the plate temperature estimation unit and the plate temperature target value as the local fuel flow rate pattern. .

  Further, the optimum fuel flow rate pattern determination unit extracts a local fuel flow rate pattern in which the estimated plate temperature is within the management range from the local fuel flow rate pattern of each target plate temperature pattern, and for the extracted local fuel flow rate pattern, The local fuel flow rate pattern with the minimum fuel supply amount may be determined as the optimum fuel flow rate pattern.

  Furthermore, the speed control unit calculates the minimum amount of deceleration of the central line speed, taking into account the adjustable time during which the central line speed does not need to be reduced by the adjustment mechanism of the continuous annealing furnace until the deceleration factor is eliminated. May be.

In order to solve the above problems, according to another aspect of the present invention, there is provided a plate temperature control method for controlling the plate temperature of the strip passed through the continuous annealing furnace to a plate temperature target value. The Such a plate temperature control method is based on the central line speed representing the transition of the central line speed so that the amount of deceleration of the central line speed from the generation to the cancellation of the deceleration factor is minimized according to the deceleration factor of the central line speed at which the strip is moved. Based on the step of setting the line speed pattern, the central line speed pattern, the target plate temperature pattern representing the transition of the plate temperature target value set arbitrarily, and the fuel flow rate pattern of the fuel supplied to the continuous annealing furnace, A step of estimating the plate temperature transition of the strip, and a step of setting a fuel flow rate pattern in which the estimated transition plate temperature is within a management range in which product quality can be guaranteed and the fuel supply amount is minimum to an optimum fuel flow rate pattern, , it looks including the, corresponding to the center line speed pattern, the target plate temperature pattern representative of a transition of a sheet temperature target value set multiple, for each target metal temperature pattern, By changing the fuel flow pattern of the fuel supplied to the secondary annealing furnace, the plate temperature transition of the strip is estimated, and for each target plate temperature pattern, the plate temperature actual value is tracked based on the estimation result of the plate temperature transition. The fuel flow pattern of one of the fuel flow patterns is set as the local fuel flow pattern of the target plate temperature pattern, and the estimated plate temperature is within the control range among the local fuel flow patterns of each target plate temperature pattern, and the fuel is supplied. The local fuel flow pattern with the smallest amount is determined as the optimum fuel flow pattern, and the target plate temperature pattern is set between the time when the deceleration factor occurs and the time when it is scheduled to be resolved. It is characterized by being set to a temperature that is higher than the plate temperature target value and within the control range .

  As described above, according to the present invention, the optimum central line speed and plate temperature target value are flexibly set when the deceleration factor occurs for the strip that passes through the continuous annealing furnace, and the central line speed is reduced. It is possible to provide a plate temperature control device and a plate temperature control method for a continuous annealing furnace capable of optimizing the fuel consumption rate from the generation of a factor to the recovery of the central line speed.

It is explanatory drawing which shows schematic structure of the continuous annealing equipment which concerns on embodiment of this invention. It is a block diagram which shows the structure of the plate temperature control apparatus which concerns on the same embodiment. It is a flowchart which shows the plate temperature control method using the plate temperature control apparatus which concerns on the same embodiment. It is a flowchart which shows the process which determines the deceleration lower limit of center line speed. It is explanatory drawing which shows an example of the pattern of plate temperature target value. It is a flowchart which shows the determination method of the optimal fuel flow pattern in each target plate | board temperature pattern. It is explanatory drawing which shows an example of the predicted plate temperature estimated with the fuel flow rate pattern set with respect to the one plate temperature target pattern, and a heating furnace simulator.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[Schematic configuration of continuous annealing equipment]
First, a steel plate is taken up as an example of a metal strip, and a schematic configuration of a strip continuous annealing facility 1 in which plate temperature is controlled by a plate temperature control device 100 according to an embodiment of the present invention will be described based on FIG. In addition, FIG. 1 is explanatory drawing which shows schematic structure of an example of the continuous annealing equipment 1 which concerns on this embodiment.

  A continuous annealing equipment 1 shown in FIG. 1 includes a welding machine 10, a pickling equipment 20, an annealing furnace 40, an entrance side looper 30 and an exit side looper 50 installed before and after the annealing furnace 40, and a skin pass mill (control). Quality rolling mill, hereinafter referred to as “SPM”) 60.

  The welding machine 10 welds the end of the previously supplied strip 5 and the end of the next supplied strip 5 with respect to the strip 5 continuously supplied from the line inlet of the continuous annealing equipment 1. The continuous strip 5 is transferred to the pickling facility 20, cleaned, and then transferred to the annealing furnace 40 via the inlet looper 30. The entry side looper 30 is a device that adjusts the supply amount of the strip 5 supplied to the annealing furnace 40. In the continuous annealing equipment 1, the strip 5 is driven by a conveying roll for passing plates. The plate passing speed of the strip 5 is measured by, for example, PLG (Pulse Generator: not shown) provided at a plurality of important points of the line.

  The annealing furnace 40 has a heating furnace 41 that heats the strip 5 passing through the furnace wall by radiant heat from a radiant tube (not shown) into which the fuel gas flows, and a heating furnace 41 that gradually heats the heating furnace 41. It comprises a soaking furnace 42 that holds the strip 5 at a predetermined temperature, a heating furnace 41, a cooling furnace 43 that cools the strip 5 heated in the soaking furnace 42, and an overaging zone 44. The strip 5 supplied to the annealing furnace 40 is transferred through the annealing furnace by a plurality of rolls, and is subjected to heat treatment so as to have a predetermined mechanical quality. The plate temperature of the strip 5 is measured by an inlet side thermometer 46 and an outlet side thermometer 45 arranged on the inlet side and outlet side of the heating furnace 41, respectively.

  The strip 5 heat-treated by the annealing furnace 40 is transferred to the SPM 60 after the feed amount is adjusted by the exit side looper 50. The SPM 60 temper-rolls the strip 5 and transfers it to a reel that takes up the heat-treated strip 5.

  In the continuous annealing facility according to the present embodiment, when the speed at which the strip 5 is transferred in the annealing furnace 40 (center line speed) must be decelerated by some deceleration factor, the product quality of the strip 5 is maintained while maintaining the product quality. A plate temperature control device 100 that controls the plate temperature within a predetermined temperature range that can guarantee product quality is provided so as not to reduce the line speed as much as possible. The plate temperature control apparatus 100 according to the present embodiment sets a central line speed during deceleration in a section of a required time until the deceleration factor is eliminated, and creates a central line speed pattern that is a transition pattern of the central line speed with respect to time. To do. Then, the plate temperature control apparatus 100 performs a simulation of the plate temperature response when an arbitrary target plate temperature pattern and fuel flow rate pattern are set for the central line speed pattern. According to the simulation, the plate temperature control apparatus 100 indicates a target plate temperature pattern and a fuel flow rate pattern in which the plate temperature is within a preset management range in which product quality can be guaranteed and the fuel consumption is minimum. The central line speed and the fuel flow rate are controlled by determining the control information used for the actual plate temperature control.

  Hereinafter, based on FIGS. 2-7, the structure and function of the plate | board temperature control apparatus 100 which concern on this embodiment are demonstrated in detail. FIG. 2 is a block diagram showing a configuration of the plate temperature control apparatus 100 according to the present embodiment. FIG. 3 is a flowchart showing a plate temperature control method using the plate temperature control apparatus 100 according to the present embodiment. FIG. 4 is a flowchart showing a process of determining a deceleration lower limit value of the center line speed (a center line speed during deceleration). FIG. 5 is an explanatory diagram showing an example of a plate temperature target value pattern. FIG. 6 is a flowchart showing a method for determining an optimum fuel flow rate pattern in each target plate temperature pattern. FIG. 7 is an explanatory diagram showing an example of the fuel flow rate pattern set for one plate temperature target pattern and the predicted plate temperature estimated by the furnace simulator 124.

[Configuration of plate temperature control device]
The plate temperature control device 100 is a device that determines the flow rate of fuel supplied to the heating furnace 41 and performs optimum plate temperature control. As shown in FIG. 2, a speed control unit 110, a plate temperature pattern control unit, and the like. 120.

  The speed control unit 110 considers the restrictions on the looper amounts of the entrance side looper 30 and the exit side looper 50, and the like, and the transition pattern (center line speed pattern) of the center line speed passing through the strip 5 when the deceleration factor is generated. Generate. The speed control unit 110 determines the minimum deceleration speed of the central line speed for securing the required time (the central line speed during deceleration) based on the deceleration factor that the central line speed must be reduced and the time required to eliminate the deceleration factor. To decide. The method for determining the central line speed during deceleration will be described later. Based on the central line speed during deceleration set by the speed control unit 110, the rotational speed of the drive motor of the transport roll passing through the strip 5 is controlled by a motor speed controller (see, for example, Patent Document 4).

  The plate temperature pattern control unit 120 generates a plurality of target plate temperature patterns based on the time required to eliminate the deceleration factor estimated in advance. Then, the plate temperature pattern control unit 120 estimates a predicted plate temperature transition pattern and a fuel flow rate pattern supplied to the heating furnace 41 for each target plate temperature pattern, and among these, the plate temperature guarantees product quality. A target plate temperature pattern is selected that does not fall below the lower limit of the possible management range and that minimizes fuel consumption. Fuel is supplied to the heating furnace 41 based on the selected target plate temperature pattern. Such a plate temperature pattern control unit 120 includes a pattern setting unit 122, a heating furnace simulator 124, a local fuel flow pattern search unit 126, and an optimum fuel flow pattern determination unit 128.

  The pattern setting unit 122 sets the plate temperature target value to a temperature higher than the temperature during normal operation at a certain timing in the required time section, and the plate temperature at the deceleration factor elimination scheduled time (that is, at the end of the required time section). N target plate temperature patterns for returning the target value to the temperature during normal operation are generated. That is, as shown in FIG. 5, the N target plate temperature patterns have different timings for setting the plate temperature target value to a temperature higher than the temperature during normal operation, and the plate temperature target value is set higher than that during normal operation. Setting time is different. Note that the temperature higher than that during normal operation is a temperature within a management range in which product quality can be guaranteed, and can be, for example, an upper limit value of the management range.

  Moreover, the pattern setting part 122 sets the fuel flow rate pattern used for the plate temperature estimation by the heating furnace simulator 124 with respect to the set target plate temperature patterns of N. For example, as will be described later, the pattern setting unit 122 updates the fuel flow rate pattern based on the simulation result of the plate temperature response by the heating furnace simulator 124, thereby a plurality of fuels as shown in FIG. A flow pattern can be created.

  The furnace simulator 124 uses the target plate temperature pattern, the fuel flow rate pattern, and the center line speed pattern as input data, and changes the plate temperature transition of the future strip in the furnace 41 under these operating conditions. It is calculated and estimated by 41 combustion and heat transfer model equations. As this combustion and heat transfer model formula, for example, a formula as described in Patent Document 3 may be used. That is, the heating furnace simulator 124 calculates a plate temperature that changes the fuel flow rate pattern for each of the plurality of N target plate temperature patterns set by the pattern setting unit 122, and estimates the transition of the predicted plate temperature by simulation. Functions as an estimation unit. This basic concept will be described next.

  In the conventional plate temperature control, normally, the temperature of the heating furnace 41 is adjusted in accordance with the change in the center line speed, and as a result, the plate temperature is controlled to become a predetermined plate temperature target value. For this reason, when the plate temperature target value is constant and the central line speed is decelerated, the residence time of the strip 5 in the furnace becomes longer, and the plate temperature becomes higher than the plate temperature target value. Therefore, in the present invention, in order to set the plate temperature to the set plate temperature target value, the fuel flow rate supplied to the heating furnace 41 is decreased to lower the temperature of the heating furnace 41. On the other hand, when the central line speed is accelerated, the flow rate of the fuel supplied to the heating furnace 41 is increased and the temperature of the heating furnace 41 is increased. Based on such a basic idea of plate temperature control, the heating furnace simulator 124 performs plate temperature control of the furnace temperature of the heating furnace 41 based on the target plate temperature pattern, the fuel flow rate pattern, and the center line speed pattern. The transition pattern of the plate temperature predicted in the case is acquired.

  The local fuel flow pattern search unit 126 evaluates the sum of squares of errors between the predicted plate temperature estimated by the furnace simulator 124 and the target plate temperature pattern by changing the fuel flow pattern in each target plate temperature pattern, and the magnitude thereof. Search for a local optimum fuel flow rate pattern that falls within the allowable range. The local optimum fuel flow pattern is output to the optimum fuel flow pattern determination unit 128 as a candidate of the optimum fuel flow pattern used as the plate temperature control value of the heating furnace 41. Further, the local fuel flow pattern search unit 126 outputs correction information for correcting the fuel flow pattern to the pattern setting unit 122.

  The optimum fuel flow rate pattern determination unit 128 determines a local optimum fuel flow rate pattern with the smallest fuel flow rate as the optimum fuel flow rate pattern from the local optimum fuel flow rate patterns determined for each target plate temperature pattern. Then, the optimum fuel flow pattern determining unit 128 outputs one fuel flow set value at the next control timing in the optimum fuel flow pattern to a fuel flow setting device (not shown) of the heating furnace 41. The heating furnace 41 performs flow rate control using a fuel flow rate controller such as a flow rate adjustment valve based on the fuel flow rate setting value received from the optimum fuel flow rate pattern determining unit 128 (see, for example, Patent Document 3).

  The actual result collecting unit 70 calculates the remaining amount of the looper of the entrance side looper 30 or the exit side looper 50 based on the actual speed value by the plate speed sensor (not shown) composed of PLG at a constant cycle, and is predicted. The deceleration factor time, the actual plate temperature value from the inlet side thermometer and the outlet side thermometer, etc. are acquired and output to the plate temperature control device 100. The plate temperature control apparatus 100 performs simulation using various operation information measured by various sensors and input from the result collecting unit 70, and updates the optimum fuel flow pattern for setting the fuel flow to the heating furnace 41. .

[Plate temperature control method]
Next, a plate temperature control method by the plate temperature control apparatus 100 described above will be described. In the plate temperature control method according to the present embodiment, it is assumed that the time (required time) required to eliminate the deceleration factor is separately estimated by an existing method or an operator. Further, it is assumed that the plate temperature control apparatus 100 can estimate the plate temperature at the control timing of N steps ahead.

  In the plate temperature control method according to the present embodiment, as shown in FIG. 3, the optimum fuel flow rate pattern is determined based on the stage of setting the center line speed pattern by the speed control unit 110 and the set center line speed pattern. It can be roughly divided into two stages.

  First, when a deceleration factor is generated in the continuous annealing facility 1, the speed control unit 110 performs the deceleration based on information about the generation of a deceleration factor such as a plate speed sensor such as a PLG installed in the continuous annealing facility 1, a LAN, or an operator. A central line speed pattern for securing a time until the factor is eliminated (required time) is created (step S100). The speed control unit 110 acquires the required time by, for example, input from an operator using an input device such as a button switch or a keyboard, or input from a management mechanism (for example, a process computer) that manages the production line including the continuous annealing equipment 1. Can do. The speed controller 110 moves the strip 5 at a constant speed (central line speed during deceleration) that is lower than the speed during normal operation from the deceleration factor occurrence time to the deceleration factor elimination scheduled time. Set to. Deceleration from the speed during normal operation to the central line speed during deceleration and acceleration from the central line speed during deceleration to the speed during normal operation are performed in the shortest possible time that can be changed from the performance of the continuous annealing equipment 1 And In the present embodiment, the central line speed pattern is set on the assumption that the central line speed is decelerated and accelerated at a constant acceleration. However, the present invention is not limited to this example.

  The central line speed during deceleration, which is the speed when the central line speed is reduced, can be set, for example, according to the process of the flowchart shown in FIG. First, the speed control part 110 acquires the generation | occurrence | production location of the deceleration factor in the continuous annealing equipment 1 (step S200). Possible places where deceleration factors occur are on the entry side, exit side, and inside the furnace. For example, as a deceleration factor that occurs on the entry side, a defect in the welding of the strip 5 can be considered, and as a deceleration factor that occurs on the exit side, operational troubles when winding the strip 5 can be considered. Further, as a deceleration factor generated in the furnace, there is a trouble that the furnace temperature cannot be adjusted. The speed control unit 110 acquires from the deceleration factor generated in the continuous annealing facility 1 where the deceleration factor is generated in the facility.

  When a deceleration factor is generated on the entrance side of the equipment, the speed control unit 110 calculates the deceleration amount of the center line speed in consideration of the restriction of the entrance side looper 30, and sets the center line speed during deceleration (step) S202). When a deceleration factor occurs on the entry side of the equipment, the entry-side looper 30 adjusts the looper amount (the length of the strip 5 between the rolls of the looper) by increasing or decreasing it to secure time until the deceleration factor is eliminated. The time that can be secured by the entry side looper 30 is limited. Usually, the remaining amount of the looper (looper amount actual value) is managed, and the remaining amount of the looper can be acquired by applying a known looper remaining amount management method also in this embodiment. In the looper remaining amount management method, processing is performed so that the passing plate amount that has fluctuated due to the speed reduction becomes equal to the amount that consumes the current looper capacity to the limit (the difference between the looper amount actual value and the looper consumption limit amount). . That is, the looper is used as much as possible to secure the time required to eliminate the deceleration factor, and the central line speed is prevented from being reduced as much as possible.

In consideration of the restriction of the looper amount by the entry-side looper 30, for example, the center line speed during deceleration can be calculated as follows. Here, Vi is the center line speed when the restriction of the entry side looper 30 is imposed. Further, the entry side looper remaining amount is li, the entry side looper required remaining amount is Li _min , the time required to eliminate the deceleration factor (required time) is T, and the speed is reduced from the speed during normal operation to the center line speed during deceleration. The deceleration time until is α, and the acceleration time from the central line speed during deceleration to the speed during normal operation is β. At this time, the center line speed Vi can be calculated by the following mathematical formula 1.
Vi = (li−Li _min ) / (T + α + β) (Formula 1)
In Formula 1, the central line speed Vi is calculated by dividing the looper amount that can be used for time adjustment by the time during which the central line speed is decelerated from that during normal operation.

  On the other hand, when a deceleration factor is generated on the exit side of the facility, the speed control unit 110 calculates the deceleration amount of the center line speed in consideration of the restriction of the exit side looper 50, and sets the center line speed during deceleration. (Step S204). When a deceleration factor occurs on the exit side of the facility, the exit side looper 50 adjusts the looper amount by increasing or decreasing it to secure the time until the deceleration factor is eliminated. In such a case, the remaining amount of the looper is managed in the same way as when a deceleration factor has occurred on the entry side of the equipment, and as much time as possible is required to eliminate the deceleration factor by using the looper as much as possible. Avoid slowing down the central line speed as much as possible.

In consideration of the restrictions on the looper amount of the exit side looper 50, the center line speed during deceleration can be calculated as follows, for example. When the central line speed Vo is constrained by the output side looper 50, the output side looper remaining amount is lo, and the output side looper accumulation limit amount is Lo _max , the central line speed Vo is calculated by the following formula 2. be able to. Similarly to Equation 1, Equation 2 also calculates the central line speed Vo by dividing the looper amount that can be used for time adjustment by the time during which the central line speed is decelerated from that during normal operation. Yes.
Vo = (Lo _max −lo) / (T + α + β) (Expression 2)

  If a deceleration factor is generated in the furnace, the center line speed is determined according to the deceleration factor (step S206). When a deceleration factor is generated in the furnace, the time for eliminating the deceleration factor cannot be secured by a looper or the like, so the center line speed must be reduced. Therefore, when a deceleration factor is generated in the furnace, the central line speed is set to a speed to be decelerated by an operator's setting input according to the deceleration factor or set in advance in a table format.

  Thus, the central line speed during deceleration is set according to the location where the deceleration factor occurs. In addition, when the deceleration factor has generate | occur | produced in the several location, a center line speed is calculated for every generation | occurrence | production location, and the minimum thing of the calculated speed is set as a center line speed at the time of deceleration. For example, when a factor of deceleration occurs on the entry side and the exit side of the facility, the speed control unit 110 performs the processes of steps S202 and S204 to calculate the speeds Vi and Vo. The smaller one of the speeds Vi and Vo is set as the center line speed during deceleration. The central line speed during deceleration is set so as not to exceed the upper limit of the central line speed. In addition, the calculation method of the center line speed shown to said Numerical formula 1 and Numerical formula 2 is an example, Comprising: What is necessary is just to set in consideration of the restrictions by the structure of the continuous plate equipment in the continuous annealing equipment 1 and peripheral equipment.

  When the center line speed during deceleration is set, the speed control unit 110 creates the center line speed pattern V (τ, *) as described above. As shown in Fig. 5, the created central line speed pattern is to decelerate from the speed during normal operation to the central line speed during deceleration at equal acceleration during the deceleration time α, and to cancel the deceleration factor from the deceleration factor occurrence time. During the required time T up to the time, the central line speed during deceleration is set, and the acceleration is accelerated from the central line speed during deceleration to the speed during normal operation during the acceleration time β from the scheduled time for decelerating the deceleration factor. Then, the speed control unit 110 cuts out a section from the current time τ to a predetermined time t, which is considered in the plate temperature control simulation, and sets the central line speed pattern V (τ, t) (step S102). In the center line speed pattern V shown in FIG. 5, the acceleration changes suddenly when switching from constant speed to constant acceleration, but the acceleration may be switched gradually. In any case, a basic speed pattern for setting the central line speed pattern may be set in advance.

  As described above, in the plate temperature control method according to the present embodiment, a central line speed pattern is set so as to reduce the amount of deceleration for decelerating the central line speed as much as possible in order to generate a deceleration factor. As a result, it is possible to shorten the time until the central line speed during normal operation is restored after the factor of deceleration is eliminated, so that the reduction in production can be suppressed.

  Next, the plate temperature pattern control unit 120 performs processing for determining an optimum fuel flow rate pattern based on the center line speed pattern set by the speed control unit 110. First, the pattern setting unit 122 sets the plate temperature target value for the plate temperature control from the N timings in the interval of the required time T of the central line speed pattern, as shown in FIG. N target plate temperature patterns that are higher than the target temperature are created (step S104).

  For example, when the plate temperature target value is fixed at the normal operating temperature (when there is no deceleration factor), if the central line speed is reduced according to the central line speed pattern, the slip residence time in the heating furnace 41 is long. As a result, the fuel supply amount is also reduced in order to lower the furnace temperature. However, when the furnace temperature changes following the change in the fuel supply amount, there is a time difference (delay) due to the heat capacity of the furnace. For this reason, the plate temperature of the strip 5 does not change immediately even if the fuel supply amount changes, and responds with a time difference. Therefore, if the central line speed is returned from the central line speed during deceleration to the normal operating speed in the shortest time after eliminating the deceleration factor, the plate temperature will fall outside the control range if the timing for increasing the fuel supply amount is delayed. there is a possibility. Therefore, the plate temperature target value is set higher before the deceleration factor elimination scheduled time in the required time section, and the fuel supply amount is increased.

  The N target plate temperature patterns can be created, for example, by dividing the section of the required time T into N equal parts and setting each division point at a timing for increasing the plate temperature target value. As the plate temperature target value increase interval ΔT becomes longer, the fuel supply amount further increases. Note that the temperature when the plate temperature target value is raised can be set to an upper limit value of a management range in which product quality can be guaranteed, for example. In this way, N target plate temperature patterns representing changes in the plate temperature target value, which are different in the plate temperature target value increase section ΔT as shown in FIG. 5, are created. As a method for dividing the section of the required time T, a divided section width dT may be set in addition to the method of previously setting the N value. In this case, the N value is determined by dividing the required time by dT.

  When the target plate temperature pattern is created, the pattern setting unit 122 prepares a first target plate temperature pattern (for example, pattern 1 in FIG. 5) TSo (1) (step S106), and the first target plate temperature pattern. An optimum fuel flow pattern (local optimum fuel flow pattern) FL for the pattern is calculated (step S108). Here, FIG. 6 shows a method of determining the local optimum fuel flow rate pattern in each target plate temperature pattern.

  First, the pattern setting unit 122 sets a fuel flow rate pattern for the first target plate temperature pattern (step S300). Here, the pattern setting unit 122 uses a preset fuel flow pattern in the first simulation, and updates the fuel flow pattern used in the previous simulation in the second and subsequent simulations. Used as The pattern setting unit 122 outputs the first target plate temperature pattern and the fuel flow rate pattern corresponding thereto to the heating furnace simulator 124.

  Next, the furnace simulator 124 estimates future plate temperature transitions under these operating conditions based on the first target plate temperature pattern, the fuel flow rate pattern, and the center line speed pattern (step S302). When the transition of the plate temperature is estimated, the local fuel flow pattern search unit 126 determines whether or not to end the simulation for the target plate temperature pattern (step S304). As will be described later, the simulation end condition may be that an evaluation function Jt (Equation 4) is calculated and the evaluation function Jt falls within an allowable range.

  When the simulation end condition is not satisfied, the local fuel flow pattern search unit 126 corrects the fuel flow pattern used for the simulation to the next fuel flow pattern with respect to the pattern setting unit 122 and performs a simulation of the plate temperature response. An instruction to perform is given (step S306). The processes in steps S300 to S306 are repeated until the simulation end condition is satisfied. By such a process, for example, a transition pattern of the predicted plate temperature estimated by the fuel flow rate pattern and the furnace simulator 124 such as pattern 2,..., Pattern n-1, pattern n shown in FIG. .

  On the other hand, when the simulation end condition is satisfied, the local fuel flow pattern search unit 126 determines the fuel flow pattern that satisfies the simulation end condition as the optimum fuel flow pattern (local fuel flow pattern) in the target plate temperature pattern. (Step S308).

In this way, the optimum fuel flow rate pattern for each target plate temperature pattern can be determined. Here, an example of a method for setting the local optimum fuel flow rate pattern for a certain target plate temperature pattern shown in FIG. 6 will be described. Here, it is assumed that the fuel flow rate is calculated using the following Equation 3 expressed by the plate temperature deviation and the center line speed.
FL (t + 1) = a × (TSo (t) −TS (t)) + b × V (t)
... (Formula 3)
TSo (t) is the target plate temperature at time t, TS (t) is the actual plate temperature at time t, V (t) is the central line speed at time t, a is a coefficient related to the plate temperature deviation, and b is This is the coefficient for the center line speed.

In the first simulation, arbitrary values are set for the coefficients a and b, and the predicted plate temperature Tsim is used for TS (t). Thus, the pattern setting unit 122 obtains the fuel flow rate pattern at the time of the first simulation and outputs it to the furnace simulator 124. Thereafter, the pattern setting unit 122 receives the simulation result of the plate temperature response by the furnace simulator 124 via the local fuel flow pattern search unit 126, and corrects the coefficients a and b of the above Equation 3. The correction of the coefficients a and b is performed, for example, so as to set the evaluation function Jt shown in the following formula 4 to be smaller. In the evaluation function shown in Formula 4, the magnitude of the difference between the target plate temperature and the simulation plate temperature is evaluated.
Jt = Σ (TSo (t) −Tsim (t)) ² (Formula 4)
The pattern setting unit 122 corrects the fuel flow rate pattern using the corrected coefficients a and b, and the next plate temperature response simulation is performed using the corrected fuel flow rate pattern.

  The simulation termination condition can be, for example, when the value of the evaluation function Jt is equal to or less than a predetermined value. In this case, the fuel flow rate pattern when the value of the evaluation function Jt is equal to or less than a predetermined value is the local optimum fuel flow rate pattern. In the above description, the fuel flow pattern FL when the evaluation function Jt converges to a predetermined value or less is the local optimum fuel flow pattern, but the present invention is not limited to such an example. Optimality is not necessarily required for one fuel flow rate pattern set for each target plate temperature pattern, and is simply set with reference to a table (not shown) that stores coefficients a and b of the evaluation function. May be. Also, other existing fuel flow rate pattern calculation methods may be used.

  Returning to FIG. 3, when the local optimum fuel flow rate pattern is determined for the target plate temperature pattern 1, the local fuel flow rate pattern search unit 126 calculates the plate temperature from the simulation result when the plate temperature control is performed using the local optimum fuel flow rate pattern. Is determined to be out of the plate temperature tolerance (step S110). Although it is desirable to reduce the fuel consumption, if the plate temperature is outside the plate temperature tolerance, the desired quality cannot be obtained and the product cannot be used. For this reason, the determination is performed. That is, this determination makes it possible to specify a fuel flow rate pattern that does not fall below the control range lower limit value and has the minimum fuel flow rate.

If the plate temperature deviates from the plate temperature tolerance, the local optimum fuel flow rate pattern of the target plate temperature pattern is excluded from candidates to be set in the actual operation of the heating furnace 41 (step S112). On the other hand, if the plate temperature is within the plate temperature tolerance, the evaluation function J is calculated using the locally optimal fuel flow rate pattern of the target plate temperature pattern as a setting candidate (step S114). The evaluation function J is set in order to evaluate the amount of fuel consumption, and is represented by the following formula 5, for example.
J = ΣQ (t) FL (t) ² (Formula 5)
Here, FL (t) is a fuel flow rate, and Q (t) is a weight parameter. The weight parameter can be set so that the influence of the prediction error is reduced by placing importance on the latest value using exponential smoothing, for example. The evaluation function J shows a smaller value as the fuel consumption is smaller. The local fuel flow pattern search unit 126 outputs the calculated value of the evaluation function J to the optimal fuel flow pattern determination unit 128.

  Thereafter, the local fuel flow pattern search unit 126 determines whether or not the local optimum fuel flow pattern has been calculated for all target plate temperature patterns (step S116). If there is an uncalculated target plate temperature pattern, the next target plate temperature pattern is prepared (step S118), and the processing from step S108 is repeated.

  On the other hand, when the processing of steps S108 to S114 is completed for all target plate temperature patterns, the optimum fuel flow rate pattern determination unit 128 performs local processing with the smallest evaluation function J among the local fuel flow rate patterns set as setting candidates. The fuel flow pattern is adopted as the optimum fuel flow pattern FLo (step S120). As described above, the evaluation function J is for evaluating the magnitude of the fuel consumption. Of the local fuel flow rate patterns in which the plate temperature can be kept within the plate temperature tolerance, the locality at which the evaluation function J is minimized. The fuel flow rate pattern is a fuel flow rate pattern with the minimum fuel consumption. Then, the fuel flow rate setting value FLo (τ + 1) one step ahead of the present time is output to the heating furnace 41 from the optimum fuel flow rate pattern FLo (step S122).

  The fuel flow rate controller of the heating furnace 41 controls the fuel flow rate by the fuel flow rate adjustment valve based on the fuel flow rate setting value input from the optimum fuel flow rate pattern determination unit 128 of the plate temperature control device 100 to control the heating furnace 41. Heat. Then, the result collection unit 70 collects result information such as the required time for eliminating the looper remaining amount and the deceleration factor, the result plate thickness, the result plate temperature, and the like, and outputs the result information to the plate temperature control device 100 at regular intervals. . In this way, the simulation of the plate temperature control is performed at a predetermined timing, the optimum fuel flow rate pattern is acquired, and the furnace temperature of the heating furnace 41 is adjusted. Thereby, the plate | board temperature of the strip 5 which passes the heating furnace 41 can be stored in a management range, without reducing a center line speed as much as possible.

  Heretofore, the plate temperature control device 100 according to the embodiment of the present invention and the plate temperature control method using the same have been described. According to the present embodiment, the central line speed pattern that minimizes the deceleration amount of the central line speed in the time required to eliminate the deceleration factor is created, and the simulation result of the plate temperature response to the created central line speed pattern Based on the above, it is possible to determine the operation amount of the plate temperature control in which the plate temperature does not deviate from the plate temperature tolerance and the fuel consumption is minimized. Thereby, it is possible to suppress a decrease in production due to a deceleration factor.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above-described embodiment, the pattern setting unit 122 collectively sets a plurality of target plate temperature patterns and performs simulation for all the set target plate temperature patterns, but the present invention is not limited to such an example. For example, the target plate temperature pattern is set each time a fuel flow rate pattern is acquired in which the estimated transition plate temperature is within the control range in which product quality can be guaranteed and the fuel supply amount is equal to or less than a predetermined reference value. Then, the simulation of the plate temperature response may be repeated.

  Moreover, in the said embodiment, although the step-shaped target plate | board temperature pattern was created, this invention is not limited to this example. The target plate temperature pattern may be any pattern in which the plate temperature target value is set higher before the deceleration factor elimination scheduled time in the required time from the occurrence of the deceleration factor to the elimination, and the target plate temperature value The way of transition can be arbitrarily set.

DESCRIPTION OF SYMBOLS 1 Continuous annealing equipment 5 Strip 10 Welding machine 20 Pickling equipment 30 Incoming looper 40 Annealing furnace 45 Outlet thermometer 46 Incoming thermometer 50 Outlet looper 60 SPM (skin pass mill)
70 Performance Collection Unit 100 Plate Temperature Control Device 110 Speed Control Unit 120 Plate Temperature Pattern Control Unit 122 Pattern Setting Unit 124 Furnace Simulator 126 Local Fuel Flow Pattern Search Unit 128 Optimal Fuel Flow Pattern Determination Unit

Claims (5)

A plate temperature control device for controlling a plate temperature of a strip passed through a continuous annealing furnace to a plate temperature target value,
A central line speed pattern representing the transition of the central line speed so that the amount of deceleration of the central line speed from the occurrence of the deceleration factor to the elimination thereof is minimized according to the deceleration factor of the central line speed for moving the strip. A speed control unit for setting
Based on the central line speed pattern, a target plate temperature pattern representing a transition of a plate temperature target value set arbitrarily, and a fuel flow rate pattern of fuel supplied to the continuous annealing furnace, a plate temperature transition of the strip is determined. A plate temperature pattern control unit that uses the fuel flow rate pattern in which the estimated transition plate temperature is within a management range in which product quality can be guaranteed and the fuel supply amount is minimum as an optimum fuel flow rate pattern;
Bei to give a,
The plate temperature pattern control unit
A target plate temperature pattern setting unit that sets a plurality of target plate temperature patterns that represent transition of the plate temperature target value, corresponding to the central line speed pattern;
For each target plate temperature pattern, changing the fuel flow rate pattern of the fuel supplied to the continuous annealing furnace, a plate temperature estimation unit that estimates the plate temperature transition of the strip,
For each target plate temperature pattern, based on the estimation result of the plate temperature transition by the plate temperature estimation unit, one fuel flow pattern of the fuel flow patterns following the plate temperature actual value is set as the target plate temperature pattern. A local fuel flow rate pattern search unit for making a local fuel flow rate pattern;
Of the local fuel flow patterns of the target plate temperature patterns, the optimum fuel for determining the local fuel flow pattern with the estimated plate temperature within the management range and the minimum fuel supply amount as the optimum fuel flow pattern. A flow rate pattern determination unit;
With
The target plate temperature pattern setting unit is configured to set the plate temperature target value higher than the plate temperature target value during normal operation and a temperature within the management range between the time when the deceleration factor is generated and the time when it is scheduled to be resolved. It characterized that you set, sheet temperature controller. The local fuel flow pattern search unit uses the fuel flow pattern that minimizes the difference between the plate temperature transition estimation result by the plate temperature estimation unit and the plate temperature target value as the local fuel flow pattern. The plate temperature control device according to claim 1 . The optimum fuel flow rate pattern determining unit includes:
Of the local fuel flow patterns of each target plate temperature pattern, extract the local fuel flow pattern in which the estimated plate temperature is within the management range,
3. The plate temperature control device according to claim 1, wherein the local fuel flow rate pattern having a minimum fuel supply amount is determined as the optimum fuel flow rate pattern for the extracted local fuel flow rate pattern. The speed control unit takes into account the adjustable time during which the central line speed does not need to be reduced by the adjustment mechanism of the continuous annealing furnace until the deceleration factor is eliminated, and the reduction amount of the central line speed is minimized. The plate temperature control apparatus according to any one of claims 1 to 3 , wherein the temperature is calculated. A plate temperature control method for controlling a plate temperature of a strip passed through a continuous annealing furnace to a plate temperature target value,
A central line speed pattern representing the transition of the central line speed so that the amount of deceleration of the central line speed from the occurrence of the deceleration factor to the elimination thereof is minimized according to the deceleration factor of the central line speed for moving the strip. Steps to set
Based on the central line speed pattern, a target plate temperature pattern representing a transition of a plate temperature target value set arbitrarily, and a fuel flow rate pattern of fuel supplied to the continuous annealing furnace, a plate temperature transition of the strip is determined. Estimating, and
The estimated plate temperature transition is within a management range in which product quality can be guaranteed, and the fuel flow pattern having the minimum fuel supply amount is set as an optimum fuel flow pattern,
Only including,
A plurality of target plate temperature patterns representing transition of the plate temperature target value corresponding to the central line speed pattern are set,
For each target plate temperature pattern, by changing the fuel flow pattern of the fuel supplied to the continuous annealing furnace, to estimate the plate temperature transition of the strip,
For each target plate temperature pattern, based on the estimation result of the plate temperature transition, one of the fuel flow patterns following the plate temperature actual value as the local fuel flow pattern of the target plate temperature pattern,
Of the local fuel flow patterns of the target plate temperature patterns, the estimated plate temperature is within the management range, and the local fuel flow pattern having the smallest fuel supply amount is determined as the optimum fuel flow pattern,
The target plate temperature pattern is set so that the plate temperature target value is higher than the plate temperature target value during normal operation and is within the control range during the period from when the deceleration factor occurs to when it is scheduled to be resolved. The plate temperature control method characterized by setting to .

Images