JPS5822325A - Optimum control means for heating oven for bloom - Google Patents

Abstract

PURPOSE:To offer the optimum control means for a heating over for bloom, by determining a time t1 to complete forecharge of blooms, determining a most economical time for heating the bloom from an estimated temperature of the bloom at the time t1 to target temperature for the discharge of the blooms, and heating the blooms with an optimum heating pattern. CONSTITUTION:An oven temperature is divided into sections for every zone unit by an oven temperature model obtained by an oven temperature model generator 3, to solve a heat balance formula. On the other hand, a blooms heat-transmission model generator 4 calculates a radiant heat-transmission rate to a blooms 1 from the oven temperature and a blooms temperature from a heat-transmission model in the steel pipe 1. In addition, a schedule means 13 catches information on an in-furnace condition, charge and discharge, so as to estimate a time to complete forecharge of the bloom 1 at the time when the bloom 1 is introduced into a heating oven 2. In succession, a period to most economically heat the bloom 1 from an estimated temperature at the time t1 to an objective discharge temperature is calculated, and a signal 15A on a forecharge completion time is outputted. This signal 15A is inputted to a means 14 to estimate a bloom temperature at the forecharge completion time. In the means 14, a bloom temperature at the forecharge completion period is operated, and the resultant temperature signal 16A is applied to a calculator 5 so that a furnace temperature set value is obtained to heat the bloom 1 through various steps thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optimal control device for a steel billet heating furnace, and in particular to an A-single door heat furnace suitable for most economically controlling the heating of steel billets to a target temperature. Concerning an optimal control device.

Generally, when heating a steel billet from an initial temperature to an extraction target temperature, the heat pattern y that minimizes the fuel consumption is determined based on the observed combustion control start time and heating time. Accordingly, we have been controlling the billet temperature.

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 the steel billet, the steel billet is charged into the furnace by a sukejima-ra which grasps the status of the steel billet in the furnace and information on charging and extraction. At the point when
Find the time to complete the prepacking of the steel billet (a state in which there is no empty furnace zone on the extraction side of the steel billet), and calculate the most economical way to move the steel billet from the predicted temperature of the billet to the extraction target temperature at the time of 3. The objective of the present invention is to provide an optimal control device for a steel billet heating furnace that makes it possible to optimally heat a steel billet in a uniform pattern by determining the baking time.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an optimum control device for a billet heating furnace according to a set of embodiments of the present invention, in which l denotes a steel billet to be heated, 1 denotes a heating furnace for heating the billet l, and J is the furnace temperature model generator for heating furnace 1, j is the heat transfer model generator for billet l, j is the furnace temperature model for heating furnace A, and the heat transfer model for billet l is used to calculate the given billet l. physical constants such as the initial temperature, dimensions, and material, and
A calculation device that calculates the optimal value from the target temperature during extraction,
/J is a schedule device that calculates the most economical heating time.

/4C predicts the temperature of the steel billet l at the time of completion of prepacking based on the prepacking completion time signal 13mu from the schedule nozzle device 7.7 and the initial temperature signal of the billet, and predicts the bloom temperature at the completion of prepacking. A prediction device that outputs a temperature signal of 14 mm, 4 is a calculation device! The combustion control start time signal it is calculated from the most economical heating time 9 m and the scheduled extraction time signal 17 m, and from the combustion control start time,
A billet temperature control device outputs a furnace temperature set value signal IO according to the optimum pattern 1t-bK, // controls burner operation for the billet heating furnace based on the furnace temperature set value signal 10MU. This is a furnace temperature controller that outputs a signal of 10m.

In this configuration, the furnace temperature model generator 3 calculates the furnace temperature del using a heat balance equation.

Divide the furnace temperature into zones and solve the heat balance equation, which calculates the combustion heat of fuel, sensible heat of combustion air, sensible heat of exhaust gas from the upstream furnace, and heat of scale formation. ,
Heat output includes heat transfer to the steel billet l, heat loss from the furnace wall, heat loss from the skid, exhaust gas loss, etc.

On the other hand, the billet heat transfer model generator determines the billet temperature from the amount of radiant heat transfer from the furnace temperature to the billet I and a model of heat conduction within the billet I.

Furthermore, the scheduler f/3 grasps the furnace status of the billet I in the furnace, the charging and extraction information of the billet I, and charges the billet I into the billet heating furnace 1. At that point, predict the time when the prefilling of the billet I will be completed, calculate the time required to bake the billet I in the most economical way from the predicted temperature at the time of prepacking completion to the extraction target temperature, and set the prepacking completion time signal 13. Output. This prepacking completion time signal ism is input to the billet temperature prediction device/IK at the time of prepacking completion, where the bloom temperature at the time of prepacking completion is calculated, and the bloom temperature signal 14m at the time of prepacking completion is given to the calculation device sK. It leaks.

In the calculation device jK, the furnace temperature peak del generator J.

The process variables from the billet heat transfer model and the output signal of the billet temperature prediction device at the time of prepacking completion are the time required to raise the billet l with the minimum fuel consumption.

The temperature rise curve of the steel billet l at that time is determined, and the most economical heating time tm and heat pattern signal ldem are output.

On the other hand, in the billet temperature control device Todoroki, combustion control is performed based on Fi, the status of the billet in the furnace, the scheduled time when the post-mortem billet is charged, the scheduled extraction time signal set by the operator, and the most economical heating time. A start time signal /1m is calculated, and a furnace temperature set value is given to the furnace temperature controller // to bake the steel billet in the most economical heat pattern KG from the combustion control start time.

As a result, the furnace temperature controller // gives a burner operation signal 12m to the billet heating furnace 1, and the billet 1 is baked according to the optimum heat pattern yK.

In other words, in the past, the combustion start time and heating time were given, and the optimal heat pattern was determined to control the billet O temperature, but in the present invention,
K when a steel piece is baked at the optimum heat for a given heating time.

Focusing on the fact that fuel consumption changes depending on heating time as shown in the fuel consumption characteristic diagram in Figure 1, find the most economical heating time that minimizes fuel consumption, and find the optimal heating time for this heating time. Heat the steel billet l according to the heat burner,
Optimal control is performed to minimize fuel consumption.

Furthermore, in order to maximize the absorption of the exhaust gas generated in the extraction side band by the steel slabs in the charging side band, the combustion control start time must be determined based on the most economical heating time and predicted changes in furnace status. Therefore, fuel consumption can be further reduced.

In this manner, determination of the start time of combustion control in a billet heating furnace has a particularly large effect on energy saving in continuous heating furnaces, especially in patch operations.

In addition, although the above embodiment illustrates the case where the optimal calculation is performed online, a configuration in which offline calculation is performed in response to various situations, this is prepared as a table, and optimal control is performed by table inspection is also possible. may be,
With this configuration, there is no wasted time between performing optimal calculations and outputting them, and not only can the response time for control output to processes be shortened, but also complex calculation parts can be replaced with a table search function. Since it can be replaced by the computer, it is possible to downsize and downsize the computing device.

As described above, according to the present invention, when heating a steel billet,
By controlling the heating furnace with a heat pattern that can control fuel consumption in the most economical way, we have developed a new optimal control device for a billet heating furnace that has a large energy-saving effect and can realize highly economical billet heating. It is something that can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optimum control system for a steel billet heating furnace according to an embodiment of the present invention, and FIG. 2 is a diagram showing fuel consumption characteristics in Km of billet heating. i-・Steel billet, J-Steel billet heating furnace, J...Furnace temperature model generator 1 prefecture...Steel billet heat transfer model generator, j-・Computer, 4
... Slab temperature control device, ti-furnace temperature controller.

Claims (1)

[Claims] Scheduling means for predicting the time at which pre-packing of steel billets will be completed on the extraction side of a billet heating furnace;
A billet temperature prediction means for predicting the temperature; a calculation means for determining the most economical heating time from the predicted temperature to the extraction target temperature; and a billet heating furnace is controlled with an optimal heat pattern based on the output of the calculation means. An optimal control device for a billet heating furnace, characterized in that it comprises a control means.