JP2003345416A - Optimization method of production planning and optimization program of production planning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently create an optimum production plan without simplification of a production model or assumption of consumed quantity of raw materials. <P>SOLUTION: This system is provided with a step which divides a target process group into plural and defines a plurality of models, which interconnects units indicating kinds of each process in a simulative manner, a step which formulates each of the models as a mathematical programming problem that is composed of more than one constraint formula based on units each model has and interconnection relationship of them, and a step that the mathematical programming problem is sequentially solved considering a prescribed production condition in the order opposite to a flow of a material/product, the solution is the optimum solution of the production planning when the obtained solution meets a certain standard, and the optimum solution of the production planning is calculated by solving the mathematical programming problem considering the production condition and the solution in the order along the flow of the material/product when the obtained solution does not meet the certain standard. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a production facility group such as a plant, a plant complex, or a complex, which produces a product from a raw material by performing a continuous process group. In formulating daily and monthly production plans, taking into account various constraints such as operating constraints, operating costs, product demand, and the timing and equipment, minimize production costs or maximize production profits. And a method for optimizing a production plan.

[0002]

2. Description of the Related Art Conventionally, a plant or a complex including a plurality of production facilities, a plant complex including a plurality of interconnected plants (hereinafter, these are collectively referred to as a "production facility group") are used. Products are produced from raw materials by performing various processes or process groups such as a batch process or a continuous process (continuous process group). Generally, these processes or process groups are performed at each production facility. First, a thorough production plan is created for the entire production equipment group.

FIG. 6 schematically shows an example of a process flow in a plant complex, which is one of a group of production facilities for implementing a continuous process group. The plant complex PC shown in FIG. 6 is the most upstream plant A for producing two types of first intermediate products X ₁ and Y from raw materials supplied from outside.
When the plant to produce a second intermediate product X ₂ a first intermediate product types X ₁ manufactured in the plant A as a raw material B
When the final product Z ₂ a second intermediate product X ₂ manufactured in the plant B and plant C to produce a final product Z ₁ as the starting material, the first intermediate product types Y produced in plant A as a raw material And a plant D that manufactures In the process of producing each intermediate product and final product, the plant complex PC uses fuel oil, fuel gas,
It consumes or produces by-products such as steam.

In reality, plant A and plant C
Is not necessarily interposed between the plant A and the plant A.
In some cases, the same or another type of first intermediate product is supplied to a plant row of a different system from the plants B and D, and the same or different type of product is produced. Further, a plurality of types of raw materials may be used in the plant A, or one or more intermediate raw materials may be used in the plants B, C, and D.

[0005] Since such a plant complex is a set of plants closely related to each other, when producing various products in the plant complex, raw materials / products or raw materials / intermediate products / final products between plants are produced. Product flows, quantitative demand / supply relationships, etc., and operational constraints and equipment constraints in each plant have been established as constraints between plants and within a plant. When each plant is operated, a production plan for the entire plant complex is formulated based on these constraints. Without such a plan, individual plants would operate in isolation, making it impossible to maintain controlled and economical production.

[0006] The production plan is created in units of a certain period. A production plan formulated on a short-term basis, for example, on a daily basis, is reflected in an actual plant operation target as daily scheduling. In addition, a production plan formulated in a longer-term unit, for example, a monthly unit, is used as a monthly planning, and a rough balance of the plant complex and a material transfer during a regular maintenance plan that requires planning from one to several months ago. It is used as a basis for daily scheduling used for arranging ships to be used. In addition, in monthly planning, a monthly production plan may be performed for a long period of time, for example, one year in order to create a plan such as a budget.

[0007]

By the way, the production plan for the above-mentioned production equipment group is determined by minimizing the production cost by restricting the production capacity and production characteristics of the product in each production equipment. Alternatively, it is performed while optimizing the production plan so as to maximize the production profit. here,
The production characteristics of a product in each production facility represent a quantitative relationship of raw materials, utilities, and the like necessary to produce a unit amount of product.

Various systems for optimizing such a production plan have been put to practical use. However, these systems are intended for a relatively simple group of steps in which individual steps are discontinuous and independently completed, such as a batch process, or a plurality of steps as shown in FIG. (1) Formulate the entire production equipment group as a single model (mathematical programming model) and obtain an optimal solution using a single objective function. Alternatively, (2) the production equipment group is divided into a plurality of models and formulated, and an objective function for each model is created, and the flow of raw material / product or raw material / intermediate product / final product (process flow) In this order, the calculation for the downstream model is performed using the optimal solution obtained by the objective function on the upstream side. That is, for example, when a final product is obtained from a raw material via an intermediate product, the conventional technology (1) formulates the entire process into one model and performs an optimal calculation, whereas the conventional technology (2) Has formulated these steps into a plurality of models, and sequentially calculated downstream models using the calculation results of the upstream model.

However, when the range of the target production equipment group is wide, when the target period of the production plan is long, or when the relationship between the continuous processes is complicated, the entire production equipment group is simply arranged according to the prior art (1). When formulated into a single model, the number of equations included in the model becomes enormous, and the convergence of the solution deteriorates. It is not unlikely that convergence may occur.

In a general continuous process, it is often necessary to draft a production plan to satisfy product demand. According to the prior art (2), such a continuous process is divided into a plurality of models. If it is formulated and calculated sequentially from the upstream of the process flow, it is difficult to calculate according to the demand of the final product.In addition, when calculating the model on the upstream side, an objective function that does not consider the demand of the final product is required. I have to use it. Therefore, there is a high possibility that the obtained solution deviates from the optimal production plan, and in some cases, the obtained solution becomes infeasible.

In order to solve these problems, conventionally,
Calculations have been made by simplifying the model or making assumptions such as the amount of raw materials used upstream of the process flow. However, if the obtained production plan is directly reflected in the operation of the plant, the production cost may deviate from the minimum cost or the maximum profit, and an inoperable production plan may be calculated. Therefore, when it is necessary to simplify the production model or make assumptions on the amount of raw materials used, etc., conduct a number of case studies with different contents of the simplification and assumptions, confirm the direction of the obtained calculation results, It is necessary for the person in charge of the production plan to adjust the calculation results to create final operation instructions for each production facility, which is inefficient and time-consuming.

Further, in the prior art (1), restrictions that cannot be normally expressed by a model, such as adjustment items between persons in charge and presentation of target values for the adjustments, are not reflected in the solution as they are, and thus are obtained. The solution planner had to make adjustments to the solution to reflect those matters, which was also inefficient and time-consuming.

The present invention has been made in view of the above problems. That is, the object of the present invention is to simplify the production model and to reduce the amount of raw materials used, even when the scope of the production plan is wide, when the continuous process is complicated, or when there are limited conditions such as product demand for the final product. An object of the present invention is to provide a production plan optimization system capable of efficiently creating an optimal production plan without assuming the following.

[0014]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies to solve the above-mentioned problems, the process group was divided into a plurality, and a plurality of models were defined so that two or more adjacent models shared one or more units. By solving the generalized mathematical programming problem sequentially in the reverse order of the flow of raw materials / products, and solving it as needed in the order along the flow of raw materials / products, large-scale and complex continuous processes can be realized. On the other hand, the inventor has found that it is possible to optimize a production plan efficiently while taking into account the restrictions on the final product, and has completed the present invention.

That is, the gist of the present invention is that when a production plan per unit period is formulated for a production facility group that produces one or more products from one or more raw materials by executing a continuous process group, A method of optimizing the production plan so that a production cost is minimized or a production profit is maximized under production conditions, wherein the process group is divided into a plurality of processes and the types of the processes are schematically represented. A model defining step of defining a plurality of models connecting the units so as to be continuous along the flow of the raw material / product and so that two or more adjacent models share one or more units; For each of the plurality of models defined in the model definition step, a constraint expression is created based on the units of each model and their interconnections, and the production A mathematical programming problem formulation step of formulating a mathematical programming problem to the solution, the mathematical programming problem is formulated in the said numerical management programming problem formulation step,
In consideration of the production conditions, the solutions are sequentially solved in the reverse order of the flow of the raw materials / products. If the obtained solution satisfies a certain standard, the solution is determined as the optimal solution of the production plan. When the obtained solution does not satisfy a certain criterion, the mathematical programming problem is solved in an order along the flow of the raw materials / products while considering the solution in accordance with the production conditions. And an optimal solution calculating step of calculating an optimal solution of the production plan.

Further, another gist of the present invention is a program for causing a computer system to function so as to execute the method, wherein the computer executes the method corresponding to each step constituting the method.・ It lies in a production plan optimization program characterized by making the system function.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The method for optimizing a production plan according to the present invention is a method for optimizing a production plan per unit period for a group of production equipment that produces products from raw materials by performing a continuous process group. This is to optimize the production plan so that production costs are minimized or production profits are maximized.

In the present invention, the process group is divided into a plurality of units, and a plurality of models formed by interconnecting units schematically representing the types of the respective processes are continuously formed along the flow of the raw material / product. And two or more adjacent models share one or more units. Then, for each of the plurality of models, a constraint formula is created based on the units included in each model and their interconnections, and a mathematical programming problem in which a production plan in each model is solved is formulated. Further, while considering the production conditions, the mathematical programming problem is sequentially solved in the reverse order of the flow of the raw materials / products. If the obtained solution satisfies a certain criterion, the solution is produced. In the case where the optimal solution of the plan is obtained and the obtained solution does not satisfy a certain standard, the mathematical programming problem is taken along the flow of the raw materials / products while considering the solution in accordance with the production conditions. The feature is that an optimal solution of the production plan is calculated by solving in an order.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for convenience of explanation, materials such as raw materials, intermediate raw materials, intermediate products, and final products that are directly handled in the continuous process group may be collectively referred to as materials (or raw materials / products). In addition, fuel oil, fuel gas, steam, and other materials that are indirectly used in the continuous process are transferred to utilities (or utilities).
May be referred to collectively.

FIG. 1 is a diagram schematically showing the configuration of a system for implementing a production plan optimizing method according to an embodiment of the present invention (a production plan optimizing system of the present embodiment). As shown in FIG. 1, the production plan optimization system 201 of the present embodiment includes an input unit 202, a model definition unit 203, a mathematical programming problem formulation unit 204, and an optimal solution calculation unit 2.
05 and the output unit 206.

The input unit 202 is adapted to appropriately input information on a continuous process group of a production facility group to be optimized for a production plan and information on production conditions. Further, information on the definition of the model in the model definition unit 203, information on the formulation of the mathematical programming problem in the mathematical programming problem formulation unit 204, information on the calculation of the optimal solution in the optimal solution calculation unit 205, and the like can also be input as appropriate. It is. Further, the input information may be appropriately changed according to its contents.
Model definition unit 203 described later, mathematical programming problem formulation unit 2
04, and is transmitted to any of the optimum solution calculation units 205. The method of inputting such information is arbitrary, and various methods such as input from a database, input using an electronic file, and manual input by an operator of the present system can be used.

The model definition unit 203 divides the continuous process group into a plurality of groups under predetermined division conditions based on the information on the continuous process group input by the input unit 202,
A plurality of models corresponding to the plurality of groups are defined. Here, the model refers to the type of each process (storage process in tank, mixing process by mixer,
This is a schematic representation of the configuration of a process group included in a target group by interconnecting units schematically representing a reaction step by a reactor, etc.).
The model definition unit 203 defines a plurality of models so as to be continuous along the flow of raw materials / products.

Here, the flow of raw materials / products (or the flow of materials) refers to the flow from raw materials to final products through intermediate raw materials / intermediate products. The plant shown in Fig. 6
Taking the continuous process group in the complex as an example, an intermediate product X1 is manufactured from the raw material in the plant A, a second intermediate product X2 is manufactured from the intermediate product X1 in the plant B, and a second intermediate product is manufactured in the plant C. X
2 to produce a final product Z1 and plant A
, The intermediate product Y is manufactured from the raw material, and the flow of manufacturing the final product Z2 from the intermediate product Y in the plant D corresponds to the flow of the raw material / product.

On the other hand, the flow from the final product to the raw material through the intermediate product / intermediate raw material is opposite to the flow of the raw material / product. In the example of FIG. 6, from the final product Z1 manufactured in the plant C to the second intermediate product X2 as a raw material, from the second intermediate product X2 manufactured in the plant B to the intermediate product X1 as the raw material. A flow from the intermediate product X1 produced in the plant A to its raw material, and
The flow from the final product Z2 manufactured in the plant D to the first intermediate product Y, which is the raw material thereof, and further from the intermediate product Y manufactured in the plant A to the raw material, is the flow of the raw material / product, respectively. This corresponds to the reverse flow.

The division condition of the continuous process group is generally set so as to coincide with the division unit in the operation or management of the production equipment group. It is preferable that the steps to be combined are included in the same group, and that the flow of the raw material / product is unidirectional between the adjacent groups.

In order to keep consistency between the amount of raw material used as a variable of the most upstream model and the amount of product production which is a variable of the most downstream model, each model is compared with the adjacent model before and after it. Are defined to share one or more units. That is, units that affect each of two or more adjacent models are incorporated into all of these models.

The division of the continuous process group and the definition of a plurality of models in the model definition unit 203 are performed by the system 20.
The first user inputs an input unit 202 and an output unit 206 described later.
It is preferable to perform a detailed operation while making appropriate adjustments via an interface such as a GUI realized by the above. However, depending on the type of the target production equipment group, it is of course possible to configure the model definition unit 203 to automatically divide the process group and define the model according to a predetermined algorithm or the like. For example, division is performed for each type of production equipment such as a tank group and a plant group, division is performed at a place where the number of raw material / product flows is relatively small, and a unit shared between adjacent models includes a tank. Are determined in advance, and the process group is automatically divided according to these rules. Thereafter, further artificial adjustments may be made to reflect items that cannot be expressed in the form of such rules.

Various types of information regarding the division of the process group and the definition of the model (the conditions for grouping the process group and the types of usable units, etc.) may be stored in the model definition section 203 in advance. The information may be externally input through the input unit 202 according to the plan and the contents of the production equipment group.

The mathematical programming problem formulation unit 204 determines, for each of the plurality of models defined by the model definition unit 203, the types of units included in each model and their interconnections, as well as predetermined production conditions. By creating one or more constraint equations, a mathematical programming problem that solves a production plan in each model is formulated as a set of these constraint equations.

Here, the constraint expression is an expression expressing various constraints in the model, and is divided into a balance expression and a conditional expression described below.

The balance formula is divided into a material balance formula (or a balance formula of raw materials and products) and a utility balance formula.
It is divided into a balance type (or a utility balance type).
The material balance formula refers to a balance formula for the production and consumption of raw materials and products, which is formulated within each process of the model and between each process, and between processes of a plurality of models. On the other hand, the utility balance formula refers to a balance formula for the production and consumption of utilities, which is formulated within each process of a model and between each process, and between processes of a plurality of models. These balance formulas, depending on the type of each unit and their interconnection relationship,
It is created according to a predetermined criterion (for example, using a predetermined template or coefficient).

On the other hand, the conditional expression refers to an expression representing various conditions relating to the execution of the continuous process group. In particular,
Expressions representing various conditions such as operating conditions of the production equipment that performs each process, conditions regarding the amount and date of arrival of the raw materials used in each process, and conditions regarding the restrictions on the amount of use and the use time of the utilities.

These constraint expressions (balance expression and conditional expression)
The formulating method and its format are arbitrary, and if necessary, can be formulated into various formats such as an integer formula, a linear formula, a nonlinear formula, and a mixed formula thereof by using a known technique. . Further, each constraint equation may be an equation or an inequality. Information necessary for formulation of constraint equations (templates and coefficients of various constraint equations, etc.) may be stored in advance in the mathematical programming problem formulation unit 204, and may be appropriately determined according to the contents of the production plan and the production equipment group. , External input unit 20
2 may be used.

The set of constraint equations (balance equation and conditional equation) created for each model in the above procedure constitutes a mathematical programming problem representing the model. By solving this mathematical programming problem, the variables in the model (the raw materials, products, utilities,
Thus, the optimal value of the consumption plan, etc.) and the optimal solution of the production plan in the model can be obtained.

The optimal solution calculation unit 205 sequentially solves the plurality of mathematical programming problems formulated by the mathematical programming problem formulation unit 204 in the reverse order of the flow of raw materials / products, and if necessary, / By solving in the order along the product flow, the optimal solution of the production plan is calculated.

"Solving" a mathematical programming problem means calculating a set of conditions for optimizing the mathematical programming problem as an optimal solution. Specifically, this is equivalent to setting an appropriate objective function in consideration of various constraints related to the mathematical programming problem, and finding a solution that maximizes or minimizes the objective function. Here, by setting the value or cost of the stock of each raw material and product, the meaning of economic stock can be expressed in the form of an equation. By including this equation in the mathematical programming problem, It is possible to reflect the stock amount of the product and the like in the calculation of the optimal production plan.

The setting of the objective function differs depending on the content of each mathematical programming problem and its position. Usually, the function that takes the maximum value or the minimum value when the production cost is the minimum or the production profit is the maximum is defined as the mathematical function. Set as the objective function of the planning problem. The optimal solution obtained when solving a mathematical programming problem using a normal objective function is a case where the constraints of the mathematical programming problem on the upstream side are not considered, that is, the constraints of the mathematical programming problem on the upstream side are obtained. This is the ideal solution when canceling. Here, assuming that approaching the ideal solution is one of the constraint conditions, the objective function for the mathematical programming problem on the upstream side is set, and the optimal solution is calculated. If there is a mathematical programming problem further upstream, the problem is similarly solved retroactively. In this way, the mathematical solution of the upstream mathematical solution is solved sequentially with the optimal solution of the mathematical solution problem on the downstream side as a constraint, and the optimal solution is calculated for the mathematical solution problem on the uppermost stream. The results are again used as constraints for the downstream mathematical programming problem.
By solving the mathematical programming problem sequentially downstream, ultimately meeting the desired demand,
It is possible to obtain an optimal solution of the production plan in which the model on the upstream side and the model on the downstream side are consistent. In other words,
The optimal solution calculated from the mathematical programming problem of any model is
It is used as a target constraint value of a mathematical programming problem of a model adjacent to this arbitrary model.

As an example of the continuous process in the plant complex shown in FIG.
5 will be described in detail. First, plant C
(Hereinafter abbreviated as “plant C model”. Other plants are also abbreviated in the same manner) to solve a mathematical programming problem formulated to produce an optimal or target quantity of product Z1. 2nd intermediate product X required for
Calculate the optimal properties and optimal quantity of 2. Next, according to the calculation result of the mathematical programming problem of the plant C model, the target property and quantity of the second intermediate product X2 in the plant B model are input, and the mathematical programming problem of the plant B model is solved. The optimum properties and the optimum amount of the intermediate product X1 are calculated. Similarly, using the mathematical programming problem of the plant D model, the first item necessary to produce the optimum amount of the product Z2 is obtained.
The optimum properties and the optimum amount of the intermediate product Y are calculated. The properties and quantity of the first intermediate product X1 calculated by the mathematical programming problem of the plant B model and the properties and quantity of the first intermediate product Y calculated by the mathematical programming problem of the plant D model are set as target values. Input to the mathematical programming problem of the A model, and calculate the optimum properties and optimum amount of the raw material.

Here, the properties and quantities of the intermediate products calculated by the respective plant models are set as conditions.
If the target properties and quantities are the same as the results of the previous calculation, this series of calculations is consistent with each plant, and can be a feasible optimal solution. On the other hand, if there is a difference between the properties and quantities of the intermediate products calculated in each plant model and the target properties and quantities calculated as the conditions of the previous model, the flow of materials will be restarted. It is necessary to solve according to. For example, in FIG. 6, the value of the optimum property and the optimum amount calculated by the plant B model of the intermediate product X1 and the optimum property and the optimum amount of the intermediate product X1 calculated by the plant A model aiming at these values If there is a difference, the properties and quantity of the intermediate product X1 calculated by the plant A model are input to the plant B model,
Solve the plant B model again. Then, the properties and quantity of the second intermediate product X2, which are the calculation results, are input to the plant C model, the plant C model is solved again, and the optimal quantity of the final product is calculated.

The optimization calculation processing in the optimum solution calculation unit 205 can use various known methods, and can be performed using commercially available optimization software.
Further, if a macro or a program in which a calculation start instruction of the optimization software and a copy / paste instruction of the obtained optimal solution data are combined is used, it is possible to automatically and continuously solve the entire mathematical programming problem. Further, information such as detailed conditions of the optimization calculation process may be externally input through the input unit 202 according to the contents of the production plan and the production equipment group.

The output unit 206 outputs the optimal solution (optimal production plan) of the production plan calculated by the optimal solution calculation unit 205. Also, information on the model defined by the model definition unit 203 and the mathematical programming problem formulation unit 20
The information on the mathematical programming problem formulated in 4 can also be output as appropriate through the output unit 206. The format of the output of such information is arbitrary, and the information can be output in various formats such as a display, a data file, and a print file.

According to the production plan optimizing system according to the present embodiment described above, two or more adjacent models share one or more units instead of treating the entire continuous process as a single model. In addition to defining the model by dividing it into a plurality of models, the mathematical programming problem formulated for these models is solved sequentially in the reverse order of the flow of raw materials / products. The optimal solution of the production plan is efficiently calculated even if the target range of the production plan is wide, the continuous process is complicated, or there are restrictions on the final product such as product demand. can do. In addition, since there is no need to simplify the production model or make assumptions about the amount of raw materials used,
There is no need to adjust the calculated optimal solution, and it is possible to obtain an optimal production plan that is not affected by the capabilities of the production planner. Therefore, the operation efficiency of each production facility such as a plant can be improved and effectively utilized.

In the case where the entire continuous process is handled as a single model without performing the grouping of the process groups as in the prior art (1), if the optimization of the model is started once, it may be interrupted on the way. In contrast, in the production planning optimization system according to the present embodiment, the process groups are grouped and defined as a plurality of models, and a mathematical programming problem is formulated for each model. In addition, it is possible to individually execute the optimization calculation of the mathematical programming problem, and to interrupt the calculation as needed. For example, even if the person in charge looks at the result of optimization calculation for a model corresponding to a certain production equipment and wants to set constraints on the model corresponding to another production equipment, the person , The calculation process can be interrupted, and operations such as manual setting of constraint conditions can be performed.

After the optimum solution calculation unit 205 calculates the optimum solution of a production plan for a certain production equipment group for a certain period of time (this is referred to as a “lower production plan”), the optimal solution of the lower production plan is calculated. Using the solution calculation results,
A production plan for a larger target range including the target range of the lower-level production plan (hereinafter, referred to as “upper-level production plan”).
You may be able to formulate. In this case, after calculating the optimal solution of the lower-level production plan, if information regarding the process group and the production condition of another production facility related to this production facility group is input through the input unit 202, the optimal Is used to calculate a production plan (upper-level production plan) for a wider range of production equipment groups including the newly targeted production equipment.

There is no particular limitation on the method of formulating the upper-level production plan, and any method may be used. In particular, (I) optimization by the production plan optimization method of the present invention, (II) Optimization by the usual optimization method, and (II
I) It is preferable that at least one of the calculations by the balance calculation can be executed.

Of these, the method (I) defines a model for the process group in the newly targeted range using the method of the present invention (the process group in the target range up to that point is defined). Definition of a model that shares one or more units with the model), formulation of a mathematical programming problem for the created model, calculation of the optimal solution for the formulated mathematical programming problem (formulated The mathematical programming problem is sequentially solved in the reverse order of the flow of the raw materials / products, and in some cases, further solved in the order along the flow of the raw materials / products). The configurations of the mathematical programming problem formulation unit 204 and the optimal solution calculation unit 205 can be used as they are.

In the method (II), a model is defined for a process group in a newly targeted range by using a conventional optimization method (with the model defined for the process group in the target range up to then). Definition of a model that does not share units between them), formulation of a mathematical programming problem for the created model, calculation of the optimal solution for the formulated mathematical programming problem (formulated mathematical programming problem, (Solution is performed in the order along the flow of raw materials / products). The above-described configurations of the model definition unit 203, the mathematical programming problem formulation unit 204, and the optimal solution calculation unit 205 are used with some modifications. be able to.

In the method (III), a balance formula is created for the process group in the newly targeted range and the process group in the previous target range, and the calculation result of the optimal solution of the lower production plan is calculated. To solve these balance equations (ie,
By performing a balance calculation), a production plan for the newly targeted range is calculated.

It should be noted that it may be configured to execute only one of the above-mentioned methods (I) to (III). May be configured so that an appropriate method can be selected and executed according to the type of the process group. Of course, the higher-level production plan may be formulated using another arbitrary method instead of the methods (I) to (III).

With the above configuration, using the calculation result of the optimal production plan (lower-order production plan) for a small range,
It is possible to efficiently formulate a production plan (upper-level production plan) for a large range, and it is easy to change the target range of the optimal production plan according to the operation status of the production equipment group.

The system for optimizing a production plan of the present embodiment can of course be used alone, but it can be used in another database (a common database 111 described later).
And the model database 112). The configuration in this case will be described below.

FIG. 2 is a diagram schematically showing a configuration in a case where the system for optimizing a production plan according to one embodiment of the present invention is used in combination with another database. The database system DBS shown in FIG. 2 includes a common database 111 in addition to the production plan optimization system 201 described above.
And a model database 112. The common database 111 and the model database 112, and the model database 112 and the production plan optimization system 201 are configured to be able to mutually input and output various data.

The model database 112 stores various data used for the production plan optimization system 201 (information on continuous process groups and production conditions of production equipment groups to be planned, information on model definitions in the model definition section 203). , Information on the formulation of the mathematical programming problem in the mathematical programming problem formulation unit 204, and information on the calculation of the optimal solution in the optimal solution calculation unit 205). On the other hand, the common database 111 manages a wider range of various data including data irrelevant to the production plan optimization system 201, although a part of the data to be managed is common to the model database 112. Specifically, it manages information such as plans and actual values on the consumption and production balance of raw materials and products of the entire target production equipment group, in other words, information on input and output of raw materials and products of the entire production equipment group It is. Each database is configured so that corresponding data can be stored, updated, and changed.

The common database 111 and the model database 112 correspond to various inputs. Any input can be input by database, electronic file, or manual input. Input data to the model database 112 include a coefficient relating to process characteristics, a coefficient relating to operation characteristics due to equipment, a coefficient relating to operation characteristics due to season, maintenance, a coefficient relating to operation characteristics according to daily operation conditions, and a production plan. The above constraint conditions and plant data such as initial stock information are listed. on the other hand,
The input data to the common database 111 includes data such as stock information of raw materials / products, consumption plan information of raw materials, expected production information of products, actual consumption information of raw materials, actual production information of products, and the like.

In the example shown in FIG. 2, the input A101, the input B102, and the input C103 are input from each production facility to the common database 111, and a part of the input is directly or processed and input to the model database 112. This is input to the production plan optimization system 201. The input D104 and the input E105 are input to the model database 112 from each production facility, and are input directly or processed to the production planning optimization system 201.

On the other hand, the calculation result of the optimal solution of the production plan by the production plan optimization system 201 is input to the model database 112 and a part of the calculation result (plan relating to the consumption / production balance of the entire production equipment group). Of the common database 1 is directly or processed
11 is input. Then, the model database 112
The calculation results of the optimal solution of the production plan by the production plan optimization system 201 and the production plan optimization system 2
Various other information about 01 (calculation results of various balance formulas, calculation results of driving conditions that serve as driving guidelines, etc.)
The report is output as a report 122. Further, from the common database 111, information on input and output of raw materials and products of the entire production equipment group, including information input from the model database 112, and information such as processing data of these results are output as a report 121. Is done.

As described above, the production planning optimization system 20
1 and a model database 112 (optimization-related information database) capable of storing, updating, and changing the information group (optimization-related information group) related to the optimization of the production plan, and the optimization-related information group and a part thereof are common. , A common database 11 capable of storing / updating / changing an information group (production equipment group related information group) on input / output of raw materials and products of the entire production equipment group
1 (production equipment group related information database), and collectively manage information from each production equipment such as a plant located in a remote place by configuring the information in a unified manner. In addition to this, it is possible to efficiently and quickly calculate an optimum production plan for a necessary range according to the operation status of each production facility, the operation plan of the entire production facility group, and the like.

In particular, individual production facilities such as plants, which constitute a group of production facilities such as a plant complex and a complex, exist in different regions and different business establishments, or exist in the same business establishment at different locations. Often have. And individual production facilities use various information. In such an environment, instead of managing information individually for each production facility group, information is collected using various information communication networks and centrally managed in the common database 111 and the model database 112 described above. Management can be made more efficient, and mistakes due to the mixture of information of the same type can be prevented. In addition, it is possible to efficiently and quickly calculate an optimal production plan for a necessary range according to the operation status of each production facility, the operation plan of the entire production facility group, and the like. In addition to this, it is possible to efficiently search various data input, the calculation result of the optimal production plan, the history of past information, etc. The effect that search is easy is obtained.

The production plan optimizing system 201 of the present embodiment described above, and the common database 111 and the model database 112 used in combination therewith are all input devices, storage devices, arithmetic processing devices (CPUs). , A cache, a RAM, etc.), and a computer system having a known configuration including an output device and the like. In particular, the input unit 202, which is a functional element of the optimization system 201, includes an input device such as a keyboard and a storage device, and the model definition unit 203, the mathematical programming problem formulation unit 204, and the optimal solution calculation unit 205 The output unit 206 includes an output device such as a screen display device and a printer.

Here, the production planning optimization system 201
In practice, a function corresponding to the above functional element reads a computer program (hereinafter, referred to as a “production plan optimization program”) recorded in the storage device or various recording media into the RAM of the arithmetic processing device, By activating this program and executing it by the CPU of the arithmetic processing unit, the CP
It is realized as an operation of U or as a cooperative operation between the CPU and an input device, a storage device, an output device, and the like.

Here, the program for optimizing the production plan is recorded on a computer-readable storage medium such as a CD-ROM, a DVD-ROM, an MO disk, etc. It is preferably executed and used directly through a storage medium reading device (not shown) of the system or after being installed in a storage device of a computer system. Alternatively, the program for optimizing the production plan is recorded in an external storage area (another computer system or the like; not shown) accessible through an information communication network (not shown) connected to the computer system. In advance,
It is also preferable to execute and use this as needed, directly from an external storage area through an information communication network, or after being installed in a storage device of a computer system.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the gist thereof. is there.

[0063]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

FIG. 3 is a flowchart schematically showing a plant complex (production equipment group) to be optimized for a production plan in the embodiment of the present invention. The plant complex shown in FIG. 3 includes a raw material supply section, a raw material tank section, a plant process section, a product and intermediate product tank section, and a product delivery section, each of which is constituted by a material balance formula required for a production plan. . Further, although not shown in FIG. 3, a utility balance formula relating to the consumption and by-product of the utility of each plant is also included.

With respect to the plant complex of FIG. 3, the raw materials are taken into consideration while considering the constraints of individual plants and the total constraints of a plurality of plants, and the manufacturing costs of individual plants and the total manufacturing costs of a plurality of plants. Optimal mixing schedule of two or more types of raw materials having different properties by the tank groups (221 to 226) and the raw material feed mixers (227, 228), optimal raw material properties fed to the plant W231 and the plant X232, and production in the plant W231 and the plant X232 Daily or monthly optimization, consisting of the optimal production distribution of finished products and intermediate products, the optimal raw material distribution fed to the plant Y233 and the plant Z234, and the optimal production distribution of the products produced in the plant Y233 and the plant Z234. Where to calculate production plans The think. When a daily production plan for one month is created, the number of required constraint equations is a huge number exceeding 70,000.

Here, when calculating the optimum production plan by the production plan optimizing system of the present invention, first, this plant complex is connected to a plurality of units each of which schematically represents a type of each process. Divided into models. In the example shown in FIG. 3, each step is represented by one unit for processes other than the plant,
Each of the plants W to Z (231 to 234) includes a plurality of steps therein, and each of these steps is represented as one unit. But,
Here, for convenience of explanation, the detailed configuration in each plant will be omitted and the explanation will proceed.

Here, a plant yard model (FIG. 4), which is a model from feedstocks A to B (211 to 213) to a raw material tank group (221 to 226), is connected to the plant complex of FIG. The raw material tank E (225) and the raw material tank F (22
6) From raw material mixer A (227) and raw material mixer B (2)
28), and further divided into two types of models, a production model (FIG. 5), which is a model including products D to M (248 to 253). That is, the tank yard model and the production model are composed of the raw material tank E (225) and the raw material tank F (2
26), raw material mixer A (227), raw material mixer B (22
8) will share the four units. In FIG. 5, raw materials A to C (214 to 216)
It indicates the raw materials to be supplied to the raw material tanks E and F (225, 226). These raw materials are actually equal to the raw materials supplied from the raw material tanks C and D (223, 224). A constraint formula is created for each of the tank yard model and the production model defined in this way, and a mathematical programming problem in which a production plan in each model is solved is formulated.

First, using the production model, a plan of properties and supply amounts of ideal raw materials for obtaining a target product is performed. Specifically, in FIG.
The information on the target production amount of each product is used as the production amount of (248 to 253), and the mathematical programming problem of the production model is solved. As a result, as the optimal solution of the production plan in the production model, the plants W and X (231, 23) are supplied from each of the raw material mixer A (227) and the raw material mixer B (228).
The properties and supply amounts of ideal raw materials to be supplied to each of 2) are calculated. At this time, the raw materials A to A supplied to the raw material tanks E and F (325, 326), respectively.
As properties and supply amounts of C (214 to 216), information on actual supply materials A to C (211 to 213),
By using the initial stock information of the tank, a solution that is closer to reality can be obtained.

Next, in the tank yard model, the raw material receiving plan (that is, the raw material mixer A (227) and the raw material mixer B (228) from each of the raw material mixers A and B (231 and 232) The ideal raw material properties to be supplied to the plant and the supply amount) as constraints, and also restrict the approach to the ideal raw material properties calculated by the production model, or the effective use of tanks, etc. Set the objective function as a condition and solve the mathematical programming problem of the tank yard model. Thereby, as the optimal solution of the operation plan in the tank yard, the raw material tank E (22
5) and the optimal properties and supply amounts of the raw materials to be supplied to each of the raw material tanks F (226) and the tanks A to
The operation plan of D (221 to 224) is calculated.

Here, the raw material tank E (225) and the raw material tank F (22) calculated by the tank yard model are used.
The properties of the raw materials to be supplied to each of the above 6) and the optimum values of the supply amounts were used for the raw materials A to C (2
14 to 216). If possible, the properties and supply amounts of the raw materials supplied from each of the raw material mixers A and B calculated as the optimal solutions by the tank yard model are calculated using the raw material mixers A and B calculated by the production model. In order to get closer to the properties and supply amount of the raw materials supplied from each of the above, the person in charge makes adjustments with the outside regarding the operation of the tank yard as necessary,
The result is reflected in the constraints of the tank yard model, and then the optimization calculation is performed again. In this manner, the properties of the raw materials to be supplied to each of the raw material tanks E and F calculated by the tank yard model and the optimum values of the supply amounts, and the raw materials A to C (214 to 216) used in the production model
If the difference between the properties and the supply amount is within the predetermined allowable limit, the optimal solution of the production plan obtained for the production model and the tank yard model is combined, and The final optimal production plan can be obtained.

On the other hand, the optimum values of the properties and supply amounts of the raw materials to be supplied to the raw material tanks E and F calculated by the tank yard model, and the raw materials A to C (214 to 216) used in the production model, respectively. If the difference between the property and the supply amount does not fall within the predetermined allowable limit, the properties of the raw material to be supplied to each of the raw material tank E and the raw material tank F calculated by the tank yard model and With the supply amount as a constraint, the mathematical programming problem of the production model is solved again. In this case, the raw materials supplied to the raw material tank E and the raw material tank F are achievable properties and supply amounts calculated by the tank yard model. Raw material mixer A (227) and raw material mixer B (2
28), the optimum properties and supply amounts of the raw materials A to C (214 to 216) to be supplied to the plant are calculated again. The calculation result of the optimal solution of the production plan obtained in the production model in this way is combined with the calculation result of the optimal solution of the production plan previously obtained in the tank yard model to obtain the final optimal production plan for the entire plant complex. I do.

In the case of the present embodiment, the properties of the raw material and the consistency of the supplied amount are determined by the units of the raw material tank E (225) and the raw material tank F (226), which are charging tanks for the plant, and the raw material mixer A ( 227) and the unit of raw material mixer B (228) are adjusted by including them in common in both the production model and the tank yard model;
It is further finely adjusted by the stock amount of the raw material tank. When the optimal production plan is calculated using the above-described conventional technology (2), if the final calculation result cannot be absorbed by the stock of the raw material tank, it is necessary to return to the tank yard model and calculate again.
In the present embodiment, the production model includes some major parts due to the restrictions of the tank model, and the production model has a mechanism in which the constraints of the tank yard model are partially considered. Is big. Therefore, usually
An inconsistent result cannot be obtained, and an optimal production plan can be obtained efficiently.

[0073]

According to the present invention, even when the target range of the production plan is wide, the continuous process is complicated, or when there are restrictions on the final product such as the product demand, the optimal solution of the production plan can be efficiently performed. Can be calculated. Also, since it is not necessary to simplify the production model or make assumptions on the amount of raw materials used, it is not necessary to adjust the calculated optimal solution, and it is possible to obtain an optimal production plan that is not affected by the ability of the production planner. it can. Therefore, it is possible to improve the operation efficiency and effectively utilize the production equipment such as a plant.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a configuration of a production plan optimization system according to an embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a configuration of a database system including a production plan optimization system according to an embodiment of the present invention.

FIG. 3 is a flowchart schematically showing a continuous process group according to the embodiment.

4 is a flowchart schematically showing a model (tank yard optimization model) created by dividing the continuous process group of FIG.

FIG. 5 is a flowchart schematically showing a model (manufactured optimization model) created by dividing the continuous process group of FIG. 3;

FIG. 6 is a flowchart schematically illustrating an example of a continuous process performed in a plant complex (a group of production facilities).

[Explanation of symbols]

101 Input A 102 Input B 103 Input C 104 Input D 105 Input E 111 Common database 112 Model database 121 Report from common database 122 Report from model database and production plan optimization system 201 Production plan optimization system 202 Input unit 203 Model definition unit 204 Mathematical programming problem formulation unit 205 Optimal solution calculation unit 206 Output unit 211 Supply material A 212 Supply material B 213 Supply material C 214 Material A 215 Material B 216 Material C 221 Material tank A 222 Material tank B 223 Material Tank C 224 Source tank D 225 Source tank E 226 Source tank F 227 Source mixer A 228 Source mixer B 231 Plant W 232 Plant X 233 Plant Y 234 Plant Z 241 Product D Link 242 Products E tank 243 intermediate product F tanks 244 Product G 245 Product H 246 Product I 247 Product J 248 Product D 249 Product E 251 product K tank 252 Product L 253 Product M 254 Product K

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Iao Bean Choa             Mau, California, United States             Nten View, Castro Street             444 MC Research and Inno             Vocation center F term (reference) 3C100 AA05 AA12 BB05 BB13                 5H004 GA34 GB01 KC06 KC10 KC13                       LA15

Claims (6)

[Claims] In order to formulate a production plan per unit period for a production facility group that produces one or more products from one or more raw materials by performing a continuous process group,
A method of optimizing the production plan so that production cost is minimized or production profit is maximized under predetermined production conditions, wherein the process group is divided into a plurality of types, and the type of each process is schematically illustrated. Models consisting of interconnected units
A model defining step of defining two or more adjacent models to share one or more units so as to be continuous along the raw material / product flow; and each of the plurality of models defined in the model defining step Formulating a constraint based on the units of each model and their interconnections, formulating a mathematical programming problem that solves the production plan in each model, and formulating the mathematical programming problem. A plurality of mathematical programming problems formulated in the steps are sequentially solved in the reverse order to the flow of the raw materials / products while considering the production conditions, and when the obtained solution satisfies a certain standard, The solution as the optimal solution for the production plan, and when the obtained solution does not satisfy a certain criterion, the solution is taken into consideration in accordance with the production conditions. An optimal solution calculating step of calculating an optimal solution of the production plan by solving the mathematical programming problem in an order along the flow of the raw materials / products. Method. 2. The method according to claim 1, wherein, in said optimum solution calculating step, an optimum solution calculated for a mathematical programming problem of an arbitrary model is used as a target constraint value of a mathematical programming problem of a model adjacent to said arbitrary model. The method for optimizing a production plan according to claim 1. 3. After calculating an optimum solution of an arbitrary production plan (hereinafter, referred to as a “lower production plan”) in the optimum solution calculation step, using the calculation result of the optimum solution of the lower production plan, 3. The production plan according to claim 1 or 2, wherein a production plan (hereinafter referred to as "upper production plan") for a larger-scale target range including the target range of the lower-level production plan is formulated. Optimization method. 4. Information on the process group, information on the production conditions, information on the definition of the model in the model definition step, information on the formulation of the mathematical programming problem in the mathematical programming problem formulation step, and Using an optimization-related information database capable of storing, updating, and changing an information group (hereinafter, referred to as an “optimization-related information group”) including at least one of the information on the calculation of the optimum solution in the solution calculation step, The method of optimizing a production plan according to any one of claims 1 to 3, wherein the optimization related information group is centrally managed by the optimization related information database. 5. Production equipment group related information capable of storing / updating / changing an information group (hereinafter, referred to as “production equipment group related information group”) including various kinds of information on input / output of raw materials and products of the entire production equipment group. The production plan optimization according to any one of claims 1 to 4, wherein the production equipment group related information group is centrally managed by the production equipment group related information database using a database. Method. 6. Formulating a production plan per unit period for a production facility group that produces one or more products from one or more raw materials by performing a continuous process group.
A program for causing a computer system to function so as to optimize the production plan so that production cost is minimized or production profit is maximized under production conditions. A program for optimizing a production plan, characterized by causing the computer system to function as means for executing operations corresponding to the steps constituting the method for optimizing a production plan described in the section.