JPS6051535B2 - Optimal control device for billet heating furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optimal control device for a steel billet heating furnace, and particularly to an optimal control device for a billet heating furnace that is most suitable for controlling the heating of a steel billet to a target temperature in the most economical manner. Regarding equipment.

Generally, when heating a steel billet from an initial temperature to an extraction target temperature, a heat pattern is found that minimizes fuel consumption for a given combustion control start time and heating time, and then Therefore, we have been controlling the temperature of the steel billet.

However, in this heating method, it cannot be said that true optimal operation is being performed because no evaluation is made as to whether or not the given combustion control start time and heating time are optimal.

Therefore, an object of the present invention is to take the above points into consideration, and when heating a steel billet, to charge the steel billet into the furnace by a scheduler that grasps the status of the steel billet in the furnace and information on charging and extraction. At the point when
Find the time when prepacking of the billet (no empty furnace zone exists on the extraction side from the billet) is completed, and bake the billet in the most economical way from the predicted temperature of the billet at this time to the extraction target temperature. An object of the present invention is to provide an optimal control device for a steel billet heating furnace that makes it possible to heat a steel billet with an optimal heat pattern by determining the time.

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

FIG. 1 is a block diagram of an optimal control device for a billet heating furnace according to an embodiment of the present invention, in which 1 is a billet to be heated, 2 is a heating furnace for heating the billet 1, and 3 is a heating furnace for heating the billet 1. Using a furnace temperature model generator for the heating furnace 2, 4 a heat transfer model generator for the copper piece 1, 5 a furnace temperature model for the heating furnace 2, and a heat transfer model for the steel piece 1, Physical constants such as initial temperature, dimensions, material, etc.
Calculation device that calculates the optimum value from the target temperature during extraction, 1
・3 is a schedule device that calculates the most economical heating time, 1
4 is a prepacking completion time signal 15 from the scheduler 13
A prediction device predicts the temperature of the steel billet 1 at the time of prepacking completion based on A and the billet initial temperature zone 7A, and outputs a bloom temperature signal 16A at the time of prepacking completion; 6 is the most economical heating from the calculation device 5; A steel billet temperature control device 11 calculates a combustion control start time signal 18A from a time 9A and an extraction scheduled time signal 17A, and outputs a furnace temperature setting signal 10A in accordance with an optimum heat pattern 19A from the combustion control start time; Temperature set value signal 10A
Based on this, a burner operation signal 10A is sent to the billet heating furnace 2.
This is a furnace temperature controller that outputs .

In this configuration, the furnace temperature model generator 3 obtains a furnace temperature model using a heat balance equation, divides the furnace temperature into sections into zones, and solves the heat balance equation. here,
Heat input is fuel combustion heat, combustion air sensible heat, exhaust gas sensible heat from the upstream section, and scale generation heat. Heat output is heat transfer to steel billet 1, heat loss from the furnace wall, and heat loss from the skid. , exhaust gas loss, etc. On the other hand, the billet heat transfer model generator 4 determines the billet temperature from the amount of radiation heat transferred from the furnace temperature to the billet 1 and from a model of heat conduction within the billet 1.

Furthermore, the schedule device 13 grasps the furnace status of the steel billet 1 in the furnace, the charging and extraction information of the steel billet 1, and when the steel billet 1 is charged into the billet heating furnace 2, the billet 1, predicts the time when the prepacking is completed, calculates the time to burn the steel billet 1 most economically from the predicted temperature at the time when the prepacking is completed to the extraction target temperature, and outputs a prepacking completion time signal 15A.

This prepacking completion time signal 15A is input to the billet temperature prediction device 14 at the time of prepacking completion, where the bloom temperature at the time of prepacking completion is calculated, and the bloom temperature signal 16A at the time of prepacking completion is given to the calculation device 5. . In the calculation device 5, the steel billet 1 given by the process variables from the furnace temperature model generator 3, the billet heat transfer model 4, and the output signal of the billet temperature prediction device 14 at the completion of prepacking is calculated to minimize fuel consumption. The baking time and the temperature rise curve of the steel piece 1 at that time are determined, and the most economical heating time 9A and a heat pattern signal 19A are output.

On the other hand, the billet temperature control device 6 controls the furnace status of the billet 1, the scheduled time when the billet will be charged in the future, and the combustion control start time based on the scheduled extraction time signal 17A and the most economical heating time set by the operator. A signal 18A is calculated, and a furnace temperature setting value is given to the furnace temperature controller 11 in order to bake the steel slab 1 along the most economical heat pattern from the combustion control start time.

As a result, the furnace temperature controller 11 gives the burner operation signal 12A to the billet heating furnace 2, and the billet 1 is baked in accordance with the most economical heat pattern.

In other words, in the past, the temperature of the steel billet was controlled by determining the optimum heat pattern based on the given combustion start time and heating time, but in the present invention,
We focused on the fact that when a steel billet is baked with the optimum heat pattern for a given heating time, the fuel consumption changes depending on the heating time, as shown in the fuel consumption characteristic diagram in Figure 2. The most economical heating time that minimizes the fuel consumption is determined, and the steel billet 1 is heated in accordance with the optimal heat pattern for this heating time, thereby performing optimal control to minimize fuel consumption. Furthermore, in order to maximize the absorption of the exhaust gas generated in the extraction side band by the steel pieces in the charging side band,
Fuel consumption can be further reduced by determining the combustion control start time based on the most economical heating time and predicted changes in the furnace status. As described above, determining the combustion control start time of a billet heating furnace has a particularly large effect on energy saving in a continuous heating furnace characterized by batch operation.

In addition, although the above example illustrates the case where the optimal calculation is performed online, it is also possible to perform offline calculation in response to various situations, prepare this as a table, and perform optimal control by searching the table. It may also be a configuration.
With this configuration, there is no wasted time between executing and outputting optimal calculations, and not only can the control output response time to the process be shortened, but also the complicated calculation part can be replaced by the table search function. As a result, it is possible to reduce the size and cost of computing devices. As described above, according to the present invention, when heating a steel billet, the heating furnace is controlled with a heat pattern that allows the fuel consumption to be controlled in the most economical manner, resulting in a large energy saving effect and excellent economic efficiency. Accordingly, it is possible to obtain a new optimum control device for a steel billet heating furnace that can realize billet heating.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optimal control device for a steel billet heating furnace according to an embodiment of the present invention, and FIG. 2 is a fuel consumption characteristic diagram for heating a billet. 1... Steel billet, 2... Steel billet heating furnace, 3.
... Furnace temperature model generator, 4 ... Slab heat transfer model generator, 5 ... Computer, 6 ...
Slab temperature control device, 11...Furnace temperature controller.

Claims (1)

[Claims] 1. A scheduler for predicting the time at which prepacking of steel billets will be completed on the extraction side of a billet heating furnace, a billet temperature prediction device for predicting the temperature of the billet at the time of completion of prepacking, and an extraction target based on the predicted temperature. Optimum control of a steel billet heating furnace, characterized in that it comprises a calculation means for determining the most economical heating time to a temperature, and a control means for controlling the steel billet heating furnace with an optimal heat pattern based on the output of the calculation means. Device.