JP2014001423A - Operation schedule generation method and operation schedule generation device of steel mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operation schedule generation device of a steel mill capable of generating an optimal operation schedule even when determination whether or not a molten pig iron preliminary treatment is executed is changed.SOLUTION: When generating an operation schedule of a steel mill having converter facilities capable of executing a molten pig iron preliminary treatment and a decarburization treatment, an operation schedule generation device of the steel mill reads manufacturing information including information related to component specifications of molten steel, determines whether or not the molten pig iron preliminary treatment is executed using the manufacturing information, calculates at least start time of the decarburization treatment on the basis of determination whether or not the molten pig iron preliminary treatment is executed determined, defines an expression including a term calculated in consideration of an execution priority and a total charge number of the molten pig iron preliminary treatment and/or a term calculated in consideration of a period of time until the decarburization treatment is started as an objective function, stores the operation schedule corresponding to a value of the objective function, calculates the objective function when the determination whether or not the molten pig iron preliminary treatment is executed is changed, and determines a schedule in which the value of the objective function stored becomes an optimal value to be the operation schedule.

Description

  The present invention relates to an operation schedule creation method and an operation schedule creation device for a steelmaking factory that create an operation schedule for a steelmaking factory that can perform hot metal preliminary treatment such as converter type hot metal preliminary treatment and decarburization treatment.

  In order to reduce the phosphorous concentration in the molten steel, after performing hot metal pretreatment in a converter different from the converter that performs decarburization treatment (hereinafter referred to as “converter type hot metal pretreatment process”). )), An operation method was established to carry out a decarburization process that lowers the carbon concentration by temporarily removing the molten metal into the ladle and then transferring it to another converter (decarburization furnace) for blowing. Has been. In addition, the molten steel processed in a decarburization furnace is handled in a unit called “charge”.

  In a steelmaking factory where the converter type hot metal pretreatment process and the decarburization process are carried out, the processing capacity of one or more converters provided for the converter type hot metal pretreatment process is provided for the decarburization process. When the operation capacity of the decarburization furnace is increased, the operation pitch of the converter hot metal preliminary treatment process does not catch up with the operation pitch of the decarburization process. The hot metal cannot be supplied to the decarburization furnace. Temporarily, from the schedule for supplying hot metal to the decarburization furnace, the transfer time from the converter in which the converter-type hot metal preliminary treatment process is performed to the converter in which the decarburization processing process is performed is traced back. Even if the schedule of the converter hot metal pretreatment process is determined by going back the time required for the pretreatment process, the waiting time from the end of the converter hot metal pretreatment process to the start of the decarburization process If the length is too long, the refractory in the ladle will be melted down or the hot metal temperature will be lowered, resulting in an increase in production cost. In such cases, it is possible to prevent the waiting time before the decarburization process from being extended by omitting the converter-type hot metal pretreatment process for steel grades that require mild component specifications such as phosphorus concentration. is there.

  For example, Patent Document 1 discloses a steelmaking process in which processing by a converter, secondary refining equipment, and a continuous casting machine is performed using backward simulation and linear programming as a technique related to the operation schedule creation of a steelmaking factory. An operation schedule creation method is disclosed. Patent Document 2 discloses a P1C2 operation in which dephosphorization processing is performed in one converter and then decarburization processing is performed in the other two converters in a converter facility including three converters. There is disclosed a method for operating a converter facility that performs an operation in combination with a C3 operation in which only a decarburization process is performed in three converters.

JP 2006-247703 A JP 2011-190501 A

In the technique disclosed in Patent Document 1, it is possible to determine the operation schedule of the processing equipment determined in advance for each charge, but the optimum processing process to be performed according to the waiting time length between the processing equipment It cannot be planned. If, by mathematical programming, formulating the execution / non-execution of converter type hot metal pretreatment for each charge as a decision variable, it becomes a mixed integer programming problem introducing 0-1 variables. For this reason, even if an attempt is made to solve an actual operation scale problem, a solution cannot be obtained in a practical calculation time. In addition, the processing schedule of the converter type hot metal pretreatment process (start time and end time of the converter type hot metal pretreatment process) is calculated by backward simulation that goes back in time from the decarburization process, and the converter type hot metal preparatory process is calculated. A method of determining an operation schedule based on a dispatching rule such as omitting the converter type hot metal preliminary treatment step when the time from the end of the treatment step to the start of the decarburization treatment step exceeds the upper limit value According to this, it is considered possible to determine the operation schedule in a short calculation time. However, in this method, the priority of the hot metal pretreatment determined from the charge component specifications cannot be reflected in the determination of the operation schedule, so the hot metal pretreatment process is omitted even for a charge that requires hot metal pretreatment. Therefore, there is a possibility that the components of the molten steel cannot be controlled within the standard range. As described above, according to the technique disclosed in Patent Document 1, it is possible to optimally determine the processing time of each facility by linear programming according to the objective function, but this is disclosed in Patent Document 1. Even with the technology, it is not possible to determine an optimal operation schedule in a steelmaking process in which it is possible to change the execution / non-execution of a process in a certain facility for each charge.
Patent Document 2 describes a method of switching between P1C2 operation and C3 operation from the cycle time and target production amount of each operation. However, even with the technique disclosed in Patent Document 2, the stand-by time from the end of the converter type hot metal preliminary treatment step to the start of the decarburization treatment step is taken into account. The operation schedule cannot be determined. Therefore, even if the technique disclosed in Patent Document 1 and the technique disclosed in Patent Document 2 are combined, the hot metal preliminary treatment is performed / not performed (hereinafter, sometimes referred to as “execution presence / absence”). It was difficult to create an optimal operation schedule in a steel factory that is expected to change.

  Therefore, the present invention is to provide an operation schedule creation method and an operation schedule creation device for a steelmaking factory that can create an optimum operation schedule even when the presence or absence of hot metal preliminary treatment is changed. And

The charge that has undergone the converter-type hot metal preliminary treatment step can shorten the processing time of the decarburization treatment step as compared with the charge that has not undergone the converter-type hot metal preliminary treatment step. Therefore, in the converter operation having the converter type hot metal preliminary treatment process and the decarburization process process, the charge and the converter type hot metal preliminary process to which the converter type hot metal pretreatment process should be preferentially performed based on the charge component specifications. Identify the charge that can omit the treatment process, and increase the number of charges to carry out the converter hot metal preliminary treatment process as much as possible while satisfying the constraints on the time until the decarburization treatment process is started Is considered preferable. As a result of intensive studies, the inventors reduced the waiting time before the decarburization treatment step by changing the implementation / non-execution of the hot metal pretreatment step represented by the converter type hot metal pretreatment step, For each of the cases where the hot metal preliminary treatment step is omitted or not, at least one term selected from the group consisting of an index related to the total number of charges and an index related to the waiting time before the start of decarburization processing is included. The present invention was completed by knowing that the operation schedule of a steelmaking factory can be optimized by adjusting the number of charges to carry out the hot metal pretreatment process so that the value of the objective function becomes larger as the objective function. I let you. By creating an operation schedule in this way, it is considered that it is possible to specify an operation schedule that can comply with charge component standards and reduce production costs in a practical calculation time.
The present invention will be described below.

  The first aspect of the present invention is a method for creating an operation schedule of a steelmaking factory having at least a hot metal preliminary process for adjusting the concentration of a specific element contained in molten steel and a converter facility capable of performing a decarburization process. In addition, the hot metal preliminary treatment can be changed between implementation / non-implementation, and the total charge determined by dividing the total amount of molten steel to be decarburized by the amount of molten steel that can be treated by one decarburization treatment. A term including a hot metal pretreatment index calculated taking into account the number and the priority of the hot metal pretreatment determined from the component specifications of the molten steel to be decarburized, and desorption after the hot metal pretreatment is completed. The objective function is an expression including at least one term selected from the group consisting of a term including a production cost index calculated in consideration of the time until charcoal processing is started, While considering hot metal reserve The value of the objective function calculated in the case of changing the charge of management is performed, the value of the objective function is employed as the operation schedule the schedule to be optimum, it is operating scheduling method of steelmaking plant.

  In the first aspect of the present invention and the other aspects of the present invention described below (hereinafter referred to as “the present invention”), the “specific element” refers to the concentration of the elements contained in the molten steel in the hot metal preliminary treatment. Is an element (for example, phosphorus etc.) that should be reduced. In the present invention, the “time from the completion of the hot metal pretreatment to the start of the decarburization process” means, for example, in the charge in which the hot metal pretreatment is performed, the time from the end of the hot metal pretreatment. The time until the start of the charcoal treatment can be set, and in the charge in which the hot metal pretreatment is not performed, the time from the end of the hot metal pretreatment to the start of the decarburization treatment can be set to zero. . In the present invention, the “term including the hot metal preliminary treatment index” refers to, for example, the first term on the right side of the following formula (1), and the “term including the production cost index” refers to, for example, the following formula (1) This is the second term on the right side. In the present invention, the “optimum value” of the value of the objective function is not particularly limited. For example, among the objective function values calculated according to the implementation / non-execution of the hot metal pretreatment for each charge, the objective function Can be set as the optimum value of the objective function value.

  Further, in the first aspect of the present invention, the hot metal pretreatment is a converter type hot metal pretreatment performed in a converter different from the converter in which the decarburization process is performed, and the steelmaking plant is a converter. It is preferable to have one or more converters in which mold hot metal preliminary treatment is performed and one or more converters in which decarburization processing is performed.

  The second aspect of the present invention is an apparatus for creating an operation schedule of a steelmaking factory having at least a hot metal preliminary process for adjusting the concentration of a specific element contained in molten steel and a converter facility capable of performing a decarburization process. A hot metal preliminary process and a decarburizing process, or a decarburizing process, a manufacturing information reading unit for reading manufacturing information including information on the composition standard of molten steel, and a hot metal preliminary process using the manufacturing information. A hot metal preliminary treatment charge determining unit that determines whether to perform or not to perform, a schedule calculation unit that calculates at least a start time of the decarburization process based on the determined execution / non-execution of the hot metal preliminary process, and a decarburization process. The total amount of molten steel to be applied is divided by the amount of molten steel that can be processed in one decarburization process. A term including a hot metal pretreatment index calculated in consideration of the degree and a production cost index calculated taking into account the time from the end of hot metal pretreatment until the start of decarburization processing An objective function calculation unit for calculating an objective function of an expression including at least one term selected from the group consisting of and a hot metal pretreatment execution / non-execution change in consideration of the priority of the hot metal pretreatment A hot metal pretreatment charge changing unit, and a schedule storage unit for storing an operation schedule corresponding to the value of the objective function calculated by the objective function calculating unit. For schedules that have not been implemented, the objective function calculation unit calculates the objective function, and the schedule in which the objective function value stored in the schedule storage unit becomes the optimum value is scheduled for operation. Determined as Le is operational scheduling device steelmaking plant.

  In the second aspect of the present invention, “calculate at least the start time of the decarburization process based on the implementation / non-execution of the determined hot metal pretreatment” means decarburization for a charge for which the hot metal pretreatment is not performed. The start time of the hot metal preliminary process and the start time of the decarburization process are calculated for the charge at which the start time of the process is calculated and the hot metal preliminary process is performed.

  Further, in the second aspect of the present invention, the hot metal pretreatment is a converter type hot metal pretreatment performed in a converter different from the converter in which the decarburization process is performed, and the steelmaking plant is a converter. It is preferable to have one or more converters in which mold hot metal preliminary treatment is performed and one or more converters in which decarburization processing is performed.

  According to the present invention, even when the presence / absence of hot metal pretreatment is changed, it is possible to create an optimum operation schedule in consideration of the charge production conditions and the constraints on the schedule. The operation schedule creation method and the operation schedule creation device can be provided.

It is a key map explaining operation schedule creation device 100 of a steelmaking factory. It is a figure explaining an example of the operation schedule in a steelmaking factory. It is a figure explaining the other example of the operation schedule in a steelmaking factory.

  Embodiments of the present invention will be described below.

  FIG. 1 is a conceptual diagram illustrating an operation schedule creation device 100 of a steelmaking factory, which is an embodiment of the operation schedule creation device of a steelmaking factory according to the present invention. Referring to FIG. 1, a book in the form of creating an operation schedule for a steel factory having one converter used in a converter type hot metal preliminary treatment process and one converter used in a decarburization treatment process The invention will be described below. In addition, the form shown below is the illustration of this invention, and this invention is steelmaking which has two converters of 1 converter for converter-type hot metal pretreatment processes, and 1 converter for decarburization processing processes. It is not limited to a form for creating a factory operation schedule.

  As shown in FIG. 1, the operation schedule creation device 100 includes a manufacturing information storage unit 101, a manufacturing information reading unit 102, a hot metal preliminary processing charge determination unit 103, a schedule calculation unit 104, and an objective function calculation unit 105. , A schedule storage unit 106, a hot metal preliminary process charge change unit 107, a calculation convergence determination unit 108, and a manufacturing schedule storage unit 109.

  The manufacturing information storage unit 101 stores manufacturing information of each charge such as a charge number, a material symbol, a component standard (phosphorus standard), a processing time, and an instruction steel time shown in Table 1, for example. When creating an operation schedule for a steel mill using the operation schedule creation device 100, manufacturing information for each charge stored in the manufacturing information storage unit 101 is read into the manufacturing information reading unit 102.

  The hot metal pretreatment charge determining unit 103 determines whether or not to perform the converter type hot metal pretreatment process for the charge whose manufacturing information is read by the manufacturing information reading unit 102. It may be determined that the converter type hot metal preliminary treatment process is performed for all the charges in which the manufacturing information is read. For example, as shown in Table 2 from the component standard (phosphorus standard) of each charge, for example. The priority of the converter type hot metal pretreatment process may be determined, and it may be determined that the converter type hot metal pretreatment process is performed only for the charge with high priority. Here, the case where a converter type hot metal preliminary treatment process is performed for all charges for which manufacturing information has been read will be described below.

  In the schedule calculation part 104, the process schedule of a converter type hot metal preliminary | backup process process and a decarburization process process is determined by calculating retroactively from the instruction | indication steel time read by the manufacturing information reading part 102. FIG. When determining the processing schedule, first, the time of the decarburization process is traced back from the charge with the latest indicated time (in the example shown in Table 1, charge No. 5). Thus, the start time of the decarburization process is determined. As shown in Table 1, the processing time of the decarburization process varies depending on whether or not the corresponding charge performs the converter type hot metal preliminary process. As described above, since the case where the converter type hot metal preliminary treatment process is performed for all charges will be described here, all the charges are charges for performing the converter type hot metal preliminary treatment process, and the decarburization processing time thereof. Since it is 30 minutes as shown in Table 1, the time that goes back 30 minutes from the indicated steel output time is the start time of the decarburization process. When the start time of the decarburization treatment process is determined in this way, the shortest transport time from the converter hot metal preliminary treatment process to the decarburization treatment process is traced back from the start time of the decarburization treatment process. The end time of the converter type hot metal preliminary treatment process is calculated. Then, starting the converter type hot metal pretreatment process by going back the processing time of the converter type hot metal pretreatment process (40 minutes in the example shown in Table 1) from the end time of the converter type hot metal pretreatment process. Determine the time. Thus, after the start time of the decarburization process in the charge with the latest indicated steel time and the start time and end time of the converter type hot metal preliminary process are determined, the indicated steel time will continue to be the second. Slowly charge (charge of charge number 4 in the example shown in Table 1), the third slowest charge (charge of charge number 3 in the example shown in Table 1), and the same calculation as above. Repeat. At this time, in order to prevent an overlap between the other charge and the processing time in the decarburization processing step and the converter type hot metal preliminary processing step, and to secure a processing interval time (for example, 5 minutes) in each step, Adjusting the transport time from the converter type hot metal preliminary treatment process to the decarburization process process, shifting the process time in the past direction, the start time of the decarburization process process in each charge, and the converter type hot metal The start time and end time of the pretreatment process are determined. FIG. 2 and Table 3 show the operation schedule determined by this method.

  As described above, the method for calculating the schedule retroactively from the indicated steel time shown in Table 1 has been described. For example, secondary refining, decarburization treatment process, and converter type hot metal from the casting start time of the continuous casting machine. You may determine the schedule of the whole steel factory retroactively with a preliminary treatment process. The schedule calculated by the schedule calculation unit 104 in this manner is input to the objective function calculation unit 105, and the objective function is calculated by the objective function calculation unit 105 based on the input information. The objective function is represented by the following formula (1).

ここで、ｉは転炉型溶銑予備処理の優先順位であり、ｊはチャージ番号である。また、ｘ_ｉ、ｊはチャージｊを優先順位ｉとして処理するときは１、そうでないときは０とし、ｙ_ｊはチャージｊにおける搬送時間上限からの超過時間であり、α_ｉは優先順位ｉのチャージを溶銑予備処理した場合の重み係数であり、βは搬送超過時間に対する生産コスト指数である。表３に示したスケジュールについて、表４に示した値に設定された各パラメータを用いて、上記式（１）で表される目的関数値ｆを計算すると、２８１になる。

Here, i is a priority order of the converter type hot metal preliminary treatment, and j is a charge number. X _{i, j} is 1 when processing charge j as priority i, 0 otherwise, y _j is an excess time from the upper limit of transport time in charge j, and α _i is of priority i This is a weighting coefficient when the charge is preliminarily treated with hot metal, and β is a production cost index with respect to the transport overtime. When the objective function value f represented by the above formula (1) is calculated for each of the schedules shown in Table 3 using the parameters set to the values shown in Table 4, 281 is obtained.

  In the schedule storage unit 106, the first schedule (the schedule shown in Table 3 in the above example) is registered as the optimal schedule, and the value of the objective function (281 in the above example) is registered as the optimal value.

  The hot metal preliminary process charge changing unit 107 changes whether or not the converter type hot metal preliminary process is performed for each charge. The change method is not particularly limited, and it is possible to change whether or not the converter type hot metal preliminary treatment is performed by a method such as generating a random number for each charge and reversing the presence or absence of the execution if it is equal to or greater than a predetermined threshold. .

  After changing the charge for performing the converter type hot metal preliminary treatment, the time calculation in the schedule calculation unit 104 and the objective function calculation in the objective function calculation unit 105 are performed again. If the calculated value of the objective function is larger than the objective function value stored in the schedule storage unit 106, the objective function value and schedule to be stored in the schedule storage unit 106 are large values. The objective function value and the schedule from which the objective function value is obtained are updated.

  Table 5 and FIG. 3 show a schedule when the presence or absence of the converter type hot metal preliminary treatment process is changed from the schedule shown in Table 3. The schedule shown in Table 5 and FIG. 3 is the schedule shown in Table 3 and FIG. 2 in that the charge of charge number 3 having a priority of 3 was changed so as not to perform the converter type hot metal preliminary treatment. Is different.

  The objective function value f for the schedule shown in Table 5 and FIG. 3 is 310, which is larger than the objective function value 281 for the schedule shown in Table 3 and FIG. Therefore, the optimum schedule and the optimum value of the objective function stored in the schedule storage unit 106 are updated.

  The calculation convergence determination unit 108 determines that the calculation is completed when the number of the above-described repetitive calculations (schedule calculation in which the presence or absence of the converter type hot metal preliminary treatment process is performed) satisfies the prescribed number of times, The stored optimal schedule is output to the manufacturing schedule storage unit 109.

  Although the case where the operation schedule of the steelmaking factory which has a converter type hot metal preliminary treatment process and a decarburization treatment process was illustrated in the said description regarding this invention was illustrated, this invention is not limited to the said form. Instead of the converter-type hot metal pretreatment process, the operation schedule of the steelmaking factory having the hot metal pretreatment process using a torpedo car in the process of conveying the hot metal from the blast furnace to the steelmaking factory may be used. The form which creates the operation schedule of the steelmaking factory which has hot metal pretreatment processes, such as the (Kanbara Reactor) method, may be sufficient.

  Further, in the above description regarding the present invention, after determining the charge for performing the converter type hot metal preliminary treatment, the form of calculating the start time and the end time of each process by retroactive calculation is exemplified, but the present invention is in this form. It is not limited. The start time and end time of each process may be calculated using mathematical programming or the like.

DESCRIPTION OF SYMBOLS 100 ... Operation schedule preparation apparatus of a steel mill 101 ... Manufacturing information storage part 102 ... Manufacturing information reading part 103 ... Hot metal preliminary process charge determination part 104 ... Schedule calculation part 105 ... Objective function calculation part 106 ... Schedule storage part 107 ... Hot metal preliminary process Charge change unit 108 ... Calculation convergence determination unit 109 ... Manufacturing schedule storage unit

Claims (4)

At least, a hot metal preliminary treatment for adjusting the concentration of a specific element contained in molten steel, and a method for creating an operation schedule of a steel factory having a converter facility capable of performing decarburization treatment,
The hot metal preliminary treatment can be changed between implementation / non-operation,
From the total number of charges determined by dividing the total amount of the molten steel subjected to the decarburization treatment by the amount of molten steel that can be processed by one decarburization treatment and the composition standard of the molten steel subjected to the decarburization treatment In consideration of the term including the hot metal preliminary treatment index calculated in consideration of the predetermined hot metal pretreatment execution priority, and the time from the completion of the hot metal preliminary treatment to the start of the decarburization treatment. An objective function is an expression including at least one term selected from the group consisting of a term including a production cost index calculated by
While considering the priority of the hot metal pretreatment, the value of the objective function is calculated when the charge at which the hot metal pretreatment is performed is changed, and the schedule in which the value of the objective function becomes the optimum value is the operation schedule As a method of creating an operation schedule for a steel factory. The hot metal pretreatment is a converter type hot metal pretreatment performed in a converter different from the converter in which the decarburization treatment is performed,
The said steelmaking factory has 1 or 2 or more converters in which the said converter type hot metal preliminary process is implemented, and 1 or 2 or more converters in which the said decarburization process is implemented. How to create an operation schedule for a steel mill. At least a hot metal preliminary treatment for adjusting the concentration of a specific element contained in molten steel, and an apparatus for creating an operation schedule of a steel factory having a converter facility capable of performing decarburization treatment,
A manufacturing information reading unit that reads manufacturing information including information on a component standard of the molten steel, in which the hot metal preliminary treatment and the decarburization treatment, or the decarburization treatment is performed,
Using the manufacturing information, a hot metal pretreatment charge determining unit for determining whether or not to perform the hot metal pretreatment,
A schedule calculation unit that calculates at least a start time of the decarburization process based on the implementation / non-execution of the hot metal preliminary process determined;
From the total number of charges determined by dividing the total amount of the molten steel subjected to the decarburization treatment by the amount of molten steel that can be processed by one decarburization treatment and the composition standard of the molten steel subjected to the decarburization treatment In consideration of the term including the hot metal preliminary treatment index calculated in consideration of the predetermined hot metal pretreatment execution priority, and the time from the completion of the hot metal preliminary treatment to the start of the decarburization treatment. An objective function calculator that calculates an objective function of an expression that includes at least one term selected from the group consisting of:
A hot metal pretreatment charge changing unit that changes execution / non-execution of the hot metal pretreatment while considering the priority of execution of the hot metal pretreatment,
A schedule storage unit for storing an operation schedule corresponding to the value of the objective function calculated by the objective function calculation unit,
For the schedule in which execution / non-execution of the hot metal pretreatment is changed in the hot metal pretreatment charge change unit, the objective function is calculated in the objective function calculation unit,
An operation schedule creation device for a steelmaking factory that determines, as an operation schedule, a schedule in which the value of the objective function stored in the schedule storage unit is an optimum value. The hot metal pretreatment is a converter type hot metal pretreatment performed in a converter different from the converter in which the decarburization treatment is performed,
The said steelmaking factory has 1 or 2 or more converters in which the said converter type hot metal preliminary process is implemented, and 1 or 2 or more converters in which the said decarburization process is implemented. Operation schedule creation device for steelworks.

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