Vessel allocation plan creation method, operation method, and vessel allocation plan creation device

Abstract

To provide a ship allocation plan creation method, an operation method, and a ship allocation plan creation device that are capable of creating a ship allocation plan which can achieve both of stable supply of raw material and minimization of cost of transport to an unloading point in consideration of sudden fluctuation in stock and fluctuation in impurity component of raw material.SOLUTION: A ship allocation plan creation method includes: data loading processing (S100) for loading information including an initial stock volume and consumption of a plurality of brands at each of a plurality of unloading points, components of each of the plurality of brands, and upper and lower limit values on an impurity component included in a raw material at each of the plurality of unloading points; requirement cargo handling amount calculation processing (S200) for performing calculation of a requirement cargo handling amount at each of the plurality of unloading points without consideration of restrictions related to transport by vessels; temporal voyage pattern creation processing (S300) for creating a temporal voyage pattern; and voyage pattern creation and selection processing (S400) for selecting a voyage pattern to be used in a ship allocation plan on the basis of a deviation from a target stock amount for a stock of raw material and excess / deficiency from the upper and lower limit values for the impurity component, and a transport cost.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a ship allocation plan creation method, an operation method, and a ship allocation plan creation device.

Background Art

[0002] When transporting raw materials by ship, it is important to appropriately formulate a transportation plan that determines the ship to be used, the goods to be loaded, and the route to the destination in order to ensure stable supply and reduce transportation costs. In particular, factories that manufacture products from the transported raw materials need to transport them from the storage areas of raw material suppliers so as to secure an inventory of raw materials, and thus stable supply is required. However, as the types of raw materials to be handled, the number of storage areas, and the number of factories that are unloading areas increase, the transportation plan becomes complicated and difficult to formulate. To solve such problems, various plan creation methods using optimization techniques such as mathematical programming methods or metaheuristics have been proposed.

[0003] At a steelworks, which is one of the application fields of the above methods, steel products are produced daily using raw materials transported from overseas. In order to stably produce high-quality products, it is necessary to adjust the components by blending a plurality of raw materials, and it is necessary to stably supply the steelworks without running out of a plurality of raw materials. On the other hand, it is necessary to reduce the transportation cost of raw materials. In order to balance quality and transportation cost, it is necessary to create an appropriate transportation plan (ship allocation plan in this case). The transportation cost includes the ship charter cost of the ship and demurrage paid to the shipowner when more cargo handling days are required than the contracted schedule.

[0004] The ports (loading areas) of the raw material suppliers are located overseas in multiple locations, and different brands of raw materials are loaded at one or multiple loading areas in a single voyage. Additionally, there are multiple unloading areas where the raw materials are supplied, and unloading is also carried out at one or multiple unloading areas in a single voyage. Multiple types of raw materials of the original brands can be loaded at one loading area. The ships responsible for the voyages use bulk carriers with divided cargo-carrying spaces. There are several sizes of bulk carriers, each with different loadable amounts and charter costs. Also, there are two types of ship contract forms. One type is a dedicated ship that has signed a long-term exclusive contract and needs to be given priority for use. The other is a spot ship arranged for each voyage. Generally, hundreds of voyages are made annually, and for each voyage, it is necessary to determine the shipping date, the ship to be used, the loading area, the planned loading at the loading area including the loading brand and the loading amount, as well as the planned unloading at the unloading area including the unloading area, the unloading brand, and the unloading amount. Since it is necessary to consider both the plans for the loading and unloading areas in this way, there are many decision items that are variables, and the possible combinations become extremely numerous. Enumerating a large number of combinations cannot be calculated in a practical amount of time. Therefore, from the perspectives of stable supply of raw materials and reduction of transportation costs, various planning methods using optimization techniques such as mathematical programming methods or metaheuristics have been proposed to obtain the optimal solution.

[0005] For example, in Patent Document 1, the operation sequence of each transportation means and the setting of the variety of transported goods are repeated, and a simulation is performed to calculate the arrival date and arrival quantity for each variety of goods based on this setting, and an optimal logistics plan is created using metaheuristics. Also, in Patent Document 2, a combination pattern of loadable and unloadable areas for each ship and a mathematical model representing the supply-demand balance constraint at the unloading area are created, and after performing an optimization calculation using mathematical programming methods, a detailed shipping plan is formulated through simulation. Additionally, in Patent Document 3, an optimization calculation is performed based on the excess or deficiency from the upper and lower inventory limits and the transportation cost, and a shipping plan is created considering both the stable supply of raw materials from multiple loading areas to multiple unloading areas and the minimization of transportation costs.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-310313 [Patent Document 2] Japanese Patent No. 4669583 [Patent Document 3] Japanese Patent No. 6904373 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] However, in Patent Document 1, the unloading place targeted in one voyage is one place, and consideration is not given to unloading at a plurality of unloading places.

[0008] In Patent Document 2, after the execution of the optimization calculation, a simulation such as non-overlapping of the ship's cargo handling on the berth is performed. Therefore, the simulation result of changing the ship's cargo handling time so as not to overlap may deviate from the result obtained by the optimization calculation, and the supply-demand balance may deteriorate. In particular, when there is no margin in the capacity of the berth, the possibility of such deterioration increases, and there is a risk of out-of-stock.

[0009] In Patent Document 3, a shipping plan can be created that takes into account both the stable supply of raw materials from a plurality of loading places to a plurality of unloading places and the minimization of transportation costs by a method that does not require simulation. However, further improvement is required due to the following circumstances. First, in actual raw material transportation, the unloading amount may be limited due to a rapid increase in raw material inventory. Therefore, a shipping plan that can cope with such a rapid increase in inventory is required. In addition, as an adjustment of components due to the blending of raw materials, a shipping plan that can suppress fluctuations in impurity components within an allowable range is required.

[0010] An object of the present disclosure is to provide a shipping plan creation method, an operation method, and a shipping plan creation device capable of creating a shipping plan that achieves both stable supply of raw materials to the unloading place and minimization of transportation costs while considering sudden fluctuations in inventory and fluctuations in impurity components of raw materials. [Means for Solving the Problems]

[0011] (1) A ship allocation plan creation method according to an embodiment of the present disclosure is a ship allocation plan creation method for formulating a ship allocation plan including a schedule for transporting raw materials of a plurality of brands by ship from a plurality of loading places to a plurality of unloading places, including a data reading process of reading information including the initial inventory and consumption of each of the plurality of brands at each of the plurality of unloading places, the components of each of the plurality of brands, the upper and lower limit values of the impurity components contained in the raw materials at each of the plurality of unloading places, the upper limit value of the yard capacity at each of the plurality of unloading places, the handling efficiency for each of the berths at the plurality of unloading places, the loadable quantity of each of the plurality of brands at each of the plurality of unloading places, the capacity of the ship, and the transportation cost of the ship; a necessary handling quantity calculation process of calculating the necessary unloading quantity at each of the plurality of unloading places without considering the constraints related to the transportation by the ship; a provisional voyage pattern creation process of creating a provisional voyage pattern by determining the loaded raw materials and the loaded quantity at each loading place in the voyage pattern and the unloaded raw materials and the unloaded quantity at each unloading place based on the calculation result of the necessary handling quantity calculation process; and a voyage pattern creation / selection process of creating a plurality of voyage patterns based on the provisional voyage pattern and selecting a voyage pattern to be used in the ship allocation plan from among the plurality of voyage patterns based on the deviation from the target inventory of the raw material inventory, the excess or deficiency from the upper and lower limit values of the impurity components, and the transportation cost.

[0012] (2) As an embodiment of the present disclosure, in (1), in the data reading process, a type list that defines a type obtained by aggregating brands that can be substituted among the plurality of brands is read, in the necessary handling quantity calculation process, the necessary unloading quantity is calculated for each type, in the provisional voyage pattern creation process, the loaded raw materials and the unloaded raw materials are determined for each type, and the provisional voyage pattern is created, In the navigation pattern creation / selection process, a navigation pattern to be used in the shipping plan is selected based on the deviation from the target inventory quantity for each type and the excess or deficiency from the upper and lower limit values of the impurity components.

[0013] (3) As one embodiment of the present disclosure, in (1) or (2), In the navigation pattern creation / selection process, as a term corresponding to the deviation, a navigation pattern to be used in the shipping plan is selected using an objective function including a value obtained by dividing the magnitude of the difference from the target inventory quantity by the upper limit value of the yard capacity.

[0014] (4) The operation method according to one embodiment of the present disclosure is The operation of the steelworks is carried out using the shipping plan formulated by any of the shipping plan formulation methods in (1) to (3).

[0015] (5) The shipping plan formulation device according to one embodiment of the present disclosure is A shipping plan formulation device that formulates a shipping plan including a schedule for transporting raw materials of a plurality of brands from a plurality of loading places to a plurality of unloading places by ship, A data reading unit that reads information including the initial inventory quantity and consumption quantity of each of the plurality of brands at each of the plurality of unloading places, the components of each of the plurality of brands, the upper and lower limit values of the impurity components contained in the raw materials at each of the plurality of unloading places, the upper limit value of the yard capacity at each of the plurality of unloading places, the handling efficiency for each of the berths at the plurality of unloading places, the loadable quantity of each of the plurality of brands at each of the plurality of unloading places, the capacity of the ship, and the transportation cost of the ship; A required handling quantity calculation unit that calculates the required unloading quantity at each of the plurality of unloading places without considering the constraints related to the transportation by the ship; A provisional navigation pattern creation unit that creates a provisional navigation pattern by determining the loaded raw materials and loading quantities at each loading place of the route pattern and the unloaded raw materials and unloading quantities at each unloading place based on the calculation result of the required handling quantity calculation unit; Create a plurality of sailing patterns based on the provisional sailing pattern, and select, from among the plurality of sailing patterns, a sailing pattern to be used in the shipping plan based on the deviation from the target inventory level of the raw material inventory, the excess or deficiency from the upper and lower limit values of the impurity components, and the transportation cost. A sailing pattern creation / selection unit is included.

Advantages of the Invention

[0016] According to the present disclosure, it is possible to provide a shipping plan creation method, an operation method, and a shipping plan creation device that can create a shipping plan that achieves both stable supply of raw materials to the unloading location and minimization of transportation costs while considering sudden fluctuations in inventory and fluctuations in the impurity components of the raw materials.

Brief Description of the Drawings

[0017]

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Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present disclosure will be described. A schedule for transporting iron ore to a steelworks will be described as an example, but the present disclosure is not limited thereto, and is applicable to, for example, the transportation of crude oil.

[0019] FIG. 1 is a block diagram of a ship allocation plan creation device 1 according to an embodiment of the present disclosure. The ship allocation plan creation device 1 includes a database 10, a data reading unit 11, a required handling amount calculation unit 12, a provisional navigation pattern creation unit 13, and a navigation pattern creation / selection unit 14. By the ship allocation plan created by the ship allocation plan creation device 1, ships can be allocated and the operation of a factory such as a steelworks can be performed. In other words, a factory such as a steelworks can be operated by an operation method using the ship allocation plan created by the ship allocation plan creation device 1.

[0020] FIG. 2 is a flowchart showing an outline of the operation of the ship allocation plan creation device 1 according to an embodiment of the present disclosure. Generally, the ship allocation plan creation device 1 according to this embodiment formulates a schedule for transporting raw materials of a plurality of brands from a plurality of loading sites to a plurality of unloading sites by ship. In order to formulate the schedule, first, the data reading unit 11 of the ship allocation plan creation device 1 executes a data reading process (step S100). In the data reading process, the data reading unit 11 reads information necessary for creating the ship allocation plan from the database 10. The necessary information includes the initial inventory quantity and consumption quantity of each of a plurality of brands at each of a plurality of unloading sites, the components of each of a plurality of brands, the upper and lower limit values of the impurity components contained in the raw materials at each of a plurality of unloading sites, and the upper limit value of the yard capacity at each of a plurality of unloading sites. Further, the necessary information includes information such as the handling efficiency for each of the berths of a plurality of unloading sites, the loadable quantity of each of a plurality of brands at each of a plurality of unloading sites, the capacity of the ship, and the transportation cost of the ship.

[0021] Next, the required handling amount calculation unit 12 executes a required handling amount calculation process (step S200). In the required handling amount calculation process, the required loading and unloading amounts at each of a plurality of unloading points are calculated without considering the restrictions related to transportation by ship.

[0022] Subsequently, the provisional voyage pattern creation unit 13 executes a provisional voyage pattern creation process (step S300). In the provisional voyage pattern creation process, a provisional voyage pattern is created based on the route pattern. The route pattern represents a combination of the routes of the ships to be deployed and is defined by the combination of the unloading time, ship size, loading place, and unloading point. The provisional voyage pattern is one in which the loaded raw materials and loading amounts at each loading place and the unloaded raw materials and unloading amounts at each unloading point are determined in the route pattern. In the provisional voyage pattern creation process, a provisional voyage pattern is created by determining the loaded raw materials and loading amounts at each loading place and the unloaded raw materials and unloading amounts at each unloading point in the route pattern based on the calculation results of the required handling amount calculation process.

[0023] Subsequently, the voyage pattern creation / selection unit 14 executes a voyage pattern creation / selection process (step S400). The voyage pattern is one in which the ships, berths, and voyage schedules used in the provisional voyage pattern are determined. The voyage schedule includes the departure date from Japan, arrival date at the loading place, departure date from the loading place, arrival date at the unloading point, start date of handling at the unloading point, end date of handling, etc. In such a process, first, a plurality of voyage patterns are created based on the provisional voyage pattern created by the provisional voyage pattern creation process. Then, from among the created plurality of voyage patterns, the voyage pattern to be used in the shipping plan is selected based on the deviation from the target inventory level of the raw material inventory, the excess or deficiency from the upper and lower limit values of the impurity components, and the transportation cost. Hereinafter, each process of the shipping plan by the shipping plan creation device 1 will be described. Here, in the required handling amount calculation process, provisional voyage pattern creation process, and voyage pattern creation / selection process in the present embodiment, the process is performed without considering the substitutability between the brands of the raw materials. That is, in the present embodiment, the inventory levels, consumption amounts, loading amounts, and unloading amounts of each brand are handled independently and the process is performed.

[0024] Next, the data reading process (step S100), the required handling amount calculation process (step S200), the provisional voyage pattern creation process (step S300), and the voyage pattern creation / selection process (step S400) that the shipping plan creation device 1 executes as the shipping plan creation method will be described in order.

[0025] [Data Reading Process] The data reading unit 11 of the shipping plan creation device 1 reads the planned period (planned start date and planned end date) and each piece of information necessary for creating the shipping plan from user input or the database 10. FIGS. 3 to 19 show examples of the information stored in the database 10. The data reading unit 11 reads these pieces of information.

[0026] FIG. 3 is information on the inventory quantity of each brand at each unloading site (unloading site 1, unloading site 2,...). The initial inventory quantity is the inventory quantity of each brand existing at each unloading site on the planned start date (initial state).

[0027] FIG. 4 is information showing the yard capacity and draft at each unloading site. The upper limit value of the yard capacity indicates the maximum value determined from the size of the yard at each unloading site. The draft indicates the draft restriction at each unloading site.

[0028] FIG. 5 is information showing the consumption quantity at each unloading site. In FIG. 5, the consumption quantity for each brand and each day is shown. The consumption quantity at each unloading site is determined based on the production plan at each unloading site. The production plan is determined based on the shipping plan, etc. in a predetermined future period. When the planned value of the consumption quantity is determined on a daily basis, it can be applied as it is, and when the planned value is determined on a monthly basis, it can be applied, for example, by dividing it by the number of days.

[0029] FIG. 6 is information showing the target inventory at each unloading site. In FIG. 6, the target inventory for each brand and each day is shown.

[0030] Figure 7 shows information on the type, powder ratio, and components for each brand. Among the components, component β, component γ, and moisture are impurity components. Component α is the target component, which is Fe in the case of iron ore, for example. Component β and component γ are, for example, SiO 2 and P.

[0031] Figure 8 shows information on the upper and lower limit values of impurity components at each loading site. The numerator and denominator correspond to the numerator and denominator when taking a ratio. That is, the upper and lower limit values are shown as the amount [kg] of the component in the numerator per 1 t of the component in the denominator. For example, at loading site 1, component β is allowed up to 54.1 kg for 1 t of component α.

[0032] Figure 9 shows information on the handling efficiency for each brand at each berth. In Figure 9, the handling efficiency for each brand is shown for each berth.

[0033] Figure 10 shows information on the capabilities of the ships, specifically the hatch sizes and the number of hatches for each ship size. The ship sizes are, for example, VLOC (Very Large Ore Carrier) size, Cape size, Panamax size, and Handy size. In Figure 6, they are represented as "VLOC", "Cape", "Panamax", and "Handy" respectively. The loadable quantity for each ship size is determined by the hatch sizes and the number of hatches shown in Figure 10.

[0034] Figure 11 shows information on the storage area and the contracted quantity for each brand. The contracted quantity and the storage area are determined based on the agreement with the supplier of the raw material, for example. Here, the contracted quantity corresponds to the loadable quantity of each brand at each storage area. Also, Figure 12 shows information on the number of handling days at each storage area.

[0035] Figure 13 shows information on the number of sailing days from Japan to each storage area. As shown in Figure 13, for example, it takes 18 days from Japan to storage area 1. Also, it takes 49 days from Japan to storage area 2.

[0036] Figure 14 shows the information on the number of sailing days between each loading port. As shown in Figure 14, it takes 7 days of sailing days between Loading Port 1 and Loading Port 2. It takes 5 days of sailing days between Loading Port 1 and Loading Port 3. Also, it takes 3 days of sailing days between Loading Port 2 and Loading Port 3.

[0037] Figure 15 shows the information on the number of sailing days between each discharging port. As shown in Figure 15, it takes 6 days of sailing days between Discharging Port 1 and Discharging Port 2. It takes 6 days of sailing days between Discharging Port 1 and Discharging Port 3. Also, it takes 1 day of sailing days between Discharging Port 2 and Discharging Port 3. Also, the information on the number of sailing days between the loading port and the discharging port is similarly stored in the database 10 and read by the data reading unit 11.

[0038] Figure 16 shows the information on the ship sizes that cannot enter each loading port and each discharging port, and the ship sizes that cannot enter each loading port and each discharging port are indicated by the names of the respective ship sizes in Figure 16.

[0039] Figure 17 shows the information on the ship sizes that cannot enter each berth and the days when cargo handling is not possible. For example, at Discharging Port 1, there are berths B1-1, B1-2, etc., and the ship sizes that cannot enter each berth are respectively set. The days when cargo handling is not possible indicate the days when cargo handling cannot be carried out at the berth, for example, due to regular repairs of facilities, etc., and are represented by the number of days elapsed from the planned start date. For example, as shown in Figure 17, at Berth B1-2 of Discharging Port 1, cargo handling cannot be carried out on the 67th, 68th, and 69th days counted from the planned start date.

[0040] Figure 18 shows the information on the ship size, the planned end date of the voyage, the DES (dispatch money) rate, the DEM (demurrage) rate, and the discharging rate of each dedicated ship. The planned end date of the voyage is represented by the number of days elapsed from the planned start date.

[0041] FIG. 19 shows information on the ship size, charter fee, DES rate, DEM rate, and discharging run of each spot ship. The DES rate, DEM rate, and discharging run are required for calculating demurrage or dispatch, and the values agreed upon in the contract are set for each ship.

[0042] [Required Handling Quantity Calculation Process] After the data reading process, the required handling quantity calculation unit 12 performs a required handling quantity calculation process. The required handling quantity calculation unit 12 first executes a provisional discharging schedule calculation. In the provisional discharging schedule calculation, the optimal inventory transition under limited constraints is calculated without considering the constraints related to transportation by the ship (such as the upper limit of the brand loading capacity of the ship, berth allocation, berth interference, etc., which will be described later). By the provisional discharging schedule calculation, it is possible to know how much quantity is required at what timing for each brand. The provisional discharging schedule calculation can be expressed in the following linear form and can be solved by the mixed linear programming method.

[0043] First, the inventory transition of each brand at each discharging place is represented by the following mathematical formulas (1-1) and (1-2).

[0044] [Number] Here, t, T, p, P, m, M, y p,m,t , unloadAmount p,m,t , InitialStock p,m , Comsum p,m,t respectively mean the following and are used in the same meaning as below in this specification. t: The number of days elapsed from the planned start date when the time series unit of the inventory transition is in days T: The set of the number of days elapsed until the end date {1..the number of days elapsed until the planned end date} p: Discharging place P: The set of discharging places m: Brand M: The set of brands y p,m,t : The inventory quantity of brand m at discharging place p on the elapsed day t unloadAmount p,m,t: The quantity of unloading of stock m at unloading location p on elapsed day t, a variable taking a value of 0 or more InitialStock p,m : The initial stock quantity of stock m at unloading location p Comsum p,m,t : The consumption quantity of stock m at unloading location p on elapsed day t

[0045] The stock of each stock at each unloading location needs to take a value of 0 or more. Therefore, the stock quantity has a constraint of "y p,m,t ≥ 0".

[0046] Also, the upper limit value shown in Fig. 4 is set for the capacity of the storage yard for the stocks unloaded at each unloading location. The constraint formula for the storage yard capacity at each unloading location is represented by the following mathematical formulas (1-3).

[0047]

Number

[0048] Also, the quantity that can be unloaded in one day is restricted by, for example, the handling efficiency of each berth and the non-handling days shown in Figs. 9 and 17. The constraint formula related to such unloading equipment is represented by the following mathematical formula (1-4).

[0049]

Number

[0050] Furthermore, in the required handling amount calculation process, optimization is performed so as to obtain a solution that minimizes the total number of unloading operations at the unloading location. As a result, it is possible to eliminate solutions in which the unloading amount is small and the number of unloading operations is large, such as performing a small amount of unloading every day. First, a variable for counting the total number of unloading operations is defined by the following equations (1-5).

[0051] [Number] Here, unload p,m,t is a variable indicating whether or not the brand m at the unloading location p on the elapsed day t has been unloaded. When it is 0, it means that unloading has not been performed, and when it is 1, it means that unloading has been performed.

[0052] The value obtained by summing up the above counting variables over the entire schedule, all brands, and all unloading locations is the total number of unloading operations. This objective function is represented by the following mathematical formula (1-6).

[0053] [Number]

[0054] The required handling amount calculation unit 12 calculates the required unloading amount based on the above mathematical formulas (1-1) to (1-6). FIG. 20 shows an example of the required unloading amount according to the number of elapsed days obtained by these calculations. The information in FIG. 20 indicates how much each brand is required at which unloading location and at what timing.

[0055] FIG. 21 shows the information on the required unloading amount per day shown in FIG. 20 aggregated over a predetermined period. In the present embodiment, the predetermined period is two weeks, which is hereinafter referred to as the "required period". For example, the required period No. 1 in FIG. 21 is the total of the required unloading amounts for two weeks from the elapsed days 1 to 14 in FIG. 20. The required period No. 2 is the total of the required unloading amounts for two weeks from the elapsed days 15 to 28 in FIG. 20. The required unloading amount in the required period is also referred to as the required frame. The required period is not limited to two weeks, and can be an arbitrary period such as one week.

[0056] [Trial Voyage Pattern Creation Process] After the required handling volume calculation process by the required handling volume calculation unit 12, the trial voyage pattern creation unit 13 enumerates route patterns and creates a trial voyage pattern by solving an optimization problem. The trial voyage pattern is a pattern that determines the combination and quantity of stowage brands at the loading place, the discharging brands and quantity at the unloading place, and the approximate time.

[0057] FIG. 22 is information showing a list of route patterns, in which all route patterns determined by the required period, ship size, loading place, and unloading place are enumerated. The information regarding the ship size, hatch size, and number of hatches in FIG. 22 is based on the information shown in FIG. 10. Route patterns that cannot be adopted due to constraints are not enumerated in FIG. 22. For example, as shown in FIG. 16, there are loading and unloading places where handling work cannot be performed due to the ship size, so combinations that do not satisfy the constraints due to the ship size are not enumerated as route patterns. In the present embodiment, a case where the maximum number of loading places in a certain route pattern is a total of two places, the first loading place and the second loading place, and the maximum number of unloading places is a total of two places, the first unloading place and the second unloading place, will be described. However, the maximum number of loading and unloading places is not limited to 2 and may be 3 or more.

[0058] The trial voyage pattern creation unit 13 solves the following optimization problem to determine the stowage brands and stowage quantities at each loading place of the route pattern, and the discharging brands and discharging quantities at each unloading place, and creates a trial voyage pattern. First, the trial voyage pattern to be created needs to satisfy the required frame. The relational expression between the discharging quantity of each route pattern and the satisfaction of the required frame is represented by the following mathematical formula (2-1).

[0059] [Equation] Here, t´, T´, r, R, RB(t´), HatchSize r , unloadH r,p,m , gapAmount p,m,t' , Demand p,m,t' respectively mean the following and are used in the same meaning hereinafter in this specification. t´: Required period T´: The set of required periods r: Shipping route pattern R: The set of shipping route patterns RB(t´): The set of shipping route patterns r for discharging at the required period t´ HatchSize r : A constant representing the capacity of one hatch set for the shipping route pattern r (hatch size) unloadH r,p,m : The unloading quantity of the brand m at the discharging place p in the shipping route pattern r, with the unit being the number of hatches gapAmount p,m,t' : A value representing the excess or deficiency from the demand frame of the brand m at the discharging place p during the required period t´ Demand p,m,t' : The demand frame of the brand m at the discharging place p during the required period t´

[0060] Also, in the provisional voyage pattern to be created, the ship's cargo is fully loaded. This constraint is represented by the following mathematical formula (2-2).

[0061]

Equation

[0062] Also, in the loading and discharging places where the ship does not call, the constraints that loading and discharging are respectively impossible are represented by the following mathematical formulas (2-3) and (2-4).

[0063]

Equation

[0064] Also, the total quantity (loadable quantity) that can be loaded for each stock is determined. Such a constraint is represented by the following mathematical formula (2-5).

[0065] [Equation] Here, SupplyUpperLmt m represents the total loadable quantity of stock m and is used in the same meaning hereinafter in this specification.

[0066] In the provisional voyage pattern creation process, it is optimized to minimize the sum of the absolute values of the values representing the excess or deficiency from the required frame. This objective function is represented by the following mathematical formula (2-6).

[0067] [Equation]

[0068] The provisional voyage pattern creation unit 13 determines the loading quantity, unloading quantity, etc. for each of the route patterns No. 1 to No. N based on the above mathematical formulas (2-1) to (2-6), and creates a provisional voyage pattern corresponding to each route pattern. FIG. 23 shows an example of a provisional voyage pattern. For example, the provisional voyage pattern 2 in FIG. 23 is a provisional voyage pattern based on the route of route pattern 2. For stock D, loading of 44 thousand tons is performed at loading area 1 and unloading of 44 thousand tons is performed at unloading area 1. Similarly, for stock E, loading of 22 thousand tons is performed at loading area 1 and unloading of 22 thousand tons is performed at unloading area 1. Also, for stocks D and E, loading of 66 thousand tons is performed at loading area 1 respectively, and unloading of 66 thousand tons is performed at unloading area 2 respectively.

[0069] [Voyage Pattern Creation and Selection Process] The provisional voyage pattern shown in FIG. 23 does not determine the vessels to be used and the voyage schedule for each required period. Also, in the provisional voyage pattern, although the discharging ports are determined, it is not determined at which berth of the discharging port the cargo handling operation will be carried out. The voyage pattern creation / selection unit 14 creates and selects a vessel allocation plan that minimizes the transportation cost while satisfying the constraints such as the draft constraints of the berths at the loading and discharging ports and the loadable amount of the raw material vessels.

[0070] The voyage pattern creation / selection unit 14 further creates a plurality of voyage patterns by combining the vessels that can be used, the voyage schedules, and the cargo handling berths for each provisional voyage pattern. Examples of the items to be combined are as follows. Vessels to be used Date of departure from Japan First discharging port cargo handling berth Number of days of vessel stay at the first discharging port (i.e., the number of days from the arrival date at the first discharging port to the start date of the first cargo handling) Second discharging port cargo handling berth Number of days of vessel stay at the second discharging port (i.e., the number of days from the arrival date at the second discharging port to the start date of the second cargo handling)

[0071] FIG. 24 shows an example of a plurality of voyage patterns created based on the provisional voyage pattern 2 in FIG. 23. Each date indicates the number of days elapsed from the planned start date. Also, each date is calculated as follows. Arrival date at the loading port = Date of departure from Japan + (Number of voyage days between Japan and the loading port) Departure date from the loading port = Arrival date at the loading port + (Number of cargo handling days at the first loading port + Number of voyage days between the first loading port and the second loading port + Number of cargo handling days at the second loading port) Arrival date at the first discharging port = Departure date from the loading port + (Number of voyage days between Japan and the loading port) Start date of cargo handling at the first discharging port = Arrival date at the first discharging port + Number of days of vessel stay at the first discharging port End date of cargo handling at the first discharging port = Start date of cargo handling at the first discharging port + Number of cargo handling days at the first discharging port Arrival date at the second discharging port = End date of cargo handling at the first discharging port + Number of voyage days between the first discharging port and the second discharging port Start date of cargo handling at the second discharging port = Arrival date at the second discharging port + Number of days of vessel stay at the second discharging port End date of cargo handling at the second discharging port = Start date of cargo handling at the second discharging port + Number of cargo handling days at the second discharging port

[0072] Here, the number of days for cargo handling at the discharging port is calculated from the discharging efficiency information and the quantity to be discharged. Also, the number of days for cargo handling at the discharging port takes into account the days when the ship cannot berth at the quay.

[0073] Here, the charter cost is set as follows. Charter cost of a dedicated ship = 0 Charter cost of a spot ship = (Number of days from the departure date in Japan to the end date of cargo handling at the second discharging port) × Cost (yen / day)

[0074] The above cost is based on the charter cost for each ship size shown in Fig. 19.

[0075] Also, when calculating the demurrage or despatch, the following excess or deficiency time is calculated. Excess or deficiency time (hr) = Cargo handling time at the discharging port (hr) - Quantity of cargo handled at the discharging port (t) / Lifting rate per ship (t / hr)

[0076] Here, the lifting rate per ship indicates the set value (contract value) of the cargo handling efficiency for each discharging port and each ship. If an efficiency exceeding the cargo handling efficiency set based on the contract can be achieved, the excess or deficiency time will be positive and a reward will be obtained. If the efficiency is below the set cargo handling efficiency, the excess or deficiency time will be negative and a penalty will occur.

[0077] When the excess or deficiency time is positive (when the cargo handling is completed earlier than scheduled), the despatch is calculated as follows based on the DES rate. On the other hand, when the excess or deficiency time is negative (when the cargo handling is completed later than scheduled), the demurrage is calculated as follows based on the DEM rate. Demurrage or despatch = DES (despatch) rate (yen / hr) × Excess or deficiency time Demurrage or despatch = DEM (demurrage) rate (yen / hr) × Excess or deficiency time

[0078] For example, the sailing pattern No.i in Fig. 24 has the Japanese departure date as the planned start date, the first discharging berth as B1-1, the second discharging berth as B2-1, and is a pattern with a layover days of 0 for both the first and second discharging ports. The sailing patterns No.i+1 and No.i+2 are patterns in which the layover days at the first or second discharging port are changed from those in the sailing pattern No.i. Also, the sailing pattern No.j is a pattern in which the second discharging berth is changed from that in the sailing pattern No.i. Further, the sailing pattern No.k is a pattern in which the Japanese departure date is changed from that in the sailing pattern No.i.

[0079] Here, when considering a combination with a changed Japanese departure date, the start date of the discharging operation at the first discharging port is made to fall within the required period of the original provisional sailing pattern. Also, an upper limit value is set for the layover days. The upper limit value is, for example, 10 days. In this case, a sailing pattern with a layover days exceeding 10 days is not created.

[0080] From among the created multiple sailing patterns, an optimization problem is solved by an objective function described later based on the deviation from the target inventory level of the inventory, the inventory transition of the impurity component, the resource constraints of the berth, and the upper limit of the contract quantity for each brand, and a sailing pattern to be used for the ship allocation plan is selected. This optimization problem is represented by the following mathematical formula.

[0081] First, at the discharging berth of the port of call, only one ship can perform the discharging operation, and other ships cannot perform the cargo handling operation at the same berth simultaneously. The constraint formula related to such berth resources is represented by the following mathematical formula (3-1).

[0082]

Equation

[0083] When using a dedicated ship, the dedicated ship must not be engaged in another voyage during the same period. If the dedicated ship is being used in another voyage, it cannot be used in the voyage pattern of the ship allocation plan. Such a constraint is represented by the following formula (3-2).

[0084]

Equation

[0085] The inventory transition at each port of call is represented by the following formulas (3-3) and (3-4). By calculating the inventory transition, sudden fluctuations in inventory can also be grasped.

[0086]

Equation

[0087] The constraint equation for the storage capacity at each unloading location is represented by the following mathematical formula (3-5).

[0088]

Number

[0089] The deviation of the inventory from the target inventory level is represented by the following mathematical formula (3-6).

[0090]

Number

[0091] Here, considering that the higher the upper limit value of the storage capacity, the higher the tolerance for the deviation, devAmount p,m,t uses the value obtained by dividing the magnitude of the difference from the target inventory level by the upper limit value of the storage capacity.

[0092] The constraint on the loadable quantity is represented by the following mathematical formula (3-7).

[0093]

Number

[0094] The inventory transition of the impurity component is represented by the following mathematical formula (3-8).

[0095]

Number

[0096] The upper and lower limit values of the inventory transition of the impurity component are represented by the following mathematical formulas (3-9) and (3-10).

[0097]

Equation

[0098] In the voyage pattern creation and selection process of this embodiment, a solution that minimizes the value of the objective function expressed as the weighted linear sum of the deviation from the target inventory level of the inventory, the excess or deficiency from the upper and lower limit values of the impurity components, and the transportation cost (laytime or dispatch fee and charter fee) is obtained. This objective function is represented by the following mathematical formula (3-11).

[0099] [Number] Here, DesDemCost v and CharterCost v each have the following meanings and are used in the same meaning hereinafter in this specification. DesDemCost v : The set value of the laytime or dispatch fee for the voyage pattern v CharterCost v : The set value of the charter fee for the voyage pattern v

[0100] The voyage pattern creation and selection unit 14 performs an optimization calculation based on the mathematical formulas (3-1) to (3-11) and selects a voyage pattern. The set of voyage patterns selected in this way becomes the ship allocation plan.

[0101] In this way, according to the ship allocation plan creation device 1 according to this embodiment, when formulating a schedule for transporting raw materials of a plurality of brands from a plurality of loading ports to a plurality of discharging ports by ship, first, the required loading and unloading volume is calculated without considering the constraints related to ship transportation. Then, the voyage pattern creation and selection unit 14 uses the provisional voyage pattern created based on the required loading and unloading volume to determine the ships and voyage schedule to be used in the provisional voyage pattern and creates a plurality of voyage patterns. The voyage pattern creation and selection unit 14 performs an optimization calculation using the objective function considering the deviation from the target inventory level of the inventory and the inventory transition of the impurity components from the plurality of voyage patterns created in this way, selects a voyage pattern, and creates a ship allocation plan. Therefore, it is possible to create a ship allocation plan that achieves both stable supply of raw materials to the discharging port and minimization of transportation costs while considering sudden fluctuations in inventory and fluctuations in the impurity components of the raw materials without performing a simulation.

[0102] Moreover, by implementing the above operations, the necessary stocks can be stably transported to each steelworks at low cost. In addition, when blending raw materials at each steelworks, it is possible to produce an economic effect of suppressing the occurrence of demurrage fees and the like that may occur for the unloading of a plurality of necessary raw materials.

[0103] FIG. 25 shows an example of a shipping plan created by the shipping plan creation method according to the present embodiment. As shown in FIG. 25, it can be seen that a shipping schedule considering multi-port unloading has been created. Here, in FIG. 25, the name of the spot ship is indicated by "Spot + unique number". The ship size is shown in parentheses. A simplified route is shown above the ship name. The thick line indicates that the ship is staying at the berth of the unloading place with the name shown at the left end, and the stock and the handling quantity (thousand tons) to be unloaded are also shown. FIGS. 26 and 27 show examples of the inventory transitions at unloading place 1 and unloading place 2. FIGS. 28 and 29 show examples of the transitions of the impurity component contents at unloading place 1 and unloading place 2. As is clear from the comparison with the manually created plan in FIGS. 26 to 29, it can be seen that the shipping plan created by the shipping plan creation method according to the present embodiment satisfies the requirements as well as or better than the manually created plan. FIG. 30 shows the value of the objective function (formula (3-11)) evaluated by comparing the present embodiment with the manually created plan in terms of the deviation from the target inventory, the excess or deficiency of the impurity components, and the transportation cost. In any item, the shipping plan created by the shipping plan creation method according to the present embodiment has a smaller value (evaluation value) in the objective function.

[0104] Here, in the present embodiment, the above optimization calculation is solved by the mixed integer programming method, but it is not limited to this. For example, the optimization problem can be solved by optimization methods such as the mixed integer programming method, constraint programming, and metaheuristics.

[0105] In addition, in order to function as the shipping plan creation device 1, a computer can be used. Such a computer stores a program describing the processing content for realizing each function of the shipping plan creation device 1 in the storage unit of the computer, and reads and executes this program by the central processing unit (CPU) of the computer.

[0106] Although the present disclosure has been described based on the drawings and embodiments, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these modifications and corrections are included in the scope of the present disclosure. For example, the functions included in each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means and steps, etc. can be combined into one or divided.

[0107] For example, in the above embodiment, in the necessary handling amount calculation process, the temporary navigation pattern creation process, and the navigation pattern creation / selection process, the process is performed without considering the substitutability between the brands of raw materials. Here, the following process considering the substitutability may be executed. First, in the data reading process, a type list that defines a type obtained by aggregating brands that are substitutable between brands among a plurality of brands is read. In the type list, for example, if brand A and brand B are substitutable, they are treated as one type. In the necessary handling amount calculation process, for example, at the unloading time and for each unloading at the unloading place, the necessary unloading amount is calculated for each type. Also, in the navigation pattern creation process, a temporary navigation pattern is created by determining the loaded raw materials and the unloaded raw materials for each type. Further, in the navigation pattern creation / selection process, a navigation pattern is selected based on the deviation from the target inventory amount for each type and the excess or deficiency from the upper and lower limit values of the impurity components.

Description of Reference Numerals

[0108] 1 Shipping plan creation device 10 Database 11 Data reading unit 12 Necessary handling amount calculation unit 13 Temporary navigation pattern creation unit 14 Navigation Pattern Creation / Selection Section

Claims

A shipping plan creation method for creating a shipping plan including a schedule for transporting raw materials of a plurality of brands from a plurality of loading ports to a plurality of unloading ports by ship, which is executed by a shipping plan creation device, comprising: a data reading process of reading information including the initial inventory quantity and consumption quantity of each of the plurality of brands at each of the plurality of unloading ports, the components of each of the plurality of brands, the upper and lower limit values of the impurity components contained in the raw materials at each of the plurality of unloading ports, the upper limit value of the yard capacity at each of the plurality of unloading ports, the handling efficiency for each of the berths at the plurality of unloading ports, the loadable quantity of each of the plurality of brands at each of the plurality of unloading ports, the capacity of the ship, and the transportation cost of the ship; a necessary handling quantity calculation process of calculating the necessary unloading quantity at each of the plurality of unloading ports without considering the constraints related to the transportation by the ship; a provisional voyage pattern creation process of creating a provisional voyage pattern by determining the loaded raw materials and loaded quantity at each loading port and the unloaded raw materials and unloaded quantity at each unloading port in the voyage pattern based on the calculation result of the necessary handling quantity calculation process; a voyage pattern creation / selection process of creating a plurality of voyage patterns based on the provisional voyage pattern and selecting, from among the plurality of voyage patterns, a voyage pattern to be used in the shipping plan based on the deviation from the target inventory quantity of the raw materials, the excess or deficiency from the upper and lower limit values of the impurity components, and the transportation cost.

2. In the data reading process, a type list that defines types obtained by aggregating brands that can be substituted among the plurality of brands is read, in the necessary handling quantity calculation process, the necessary unloading quantity is calculated for each type, in the provisional voyage pattern creation process, the loaded raw materials and unloaded raw materials are determined for each type and the provisional voyage pattern is created, in the voyage pattern creation / selection process, the voyage pattern to be used in the shipping plan is selected based on the deviation from the target inventory quantity for each type and the excess or deficiency from the upper and lower limit values of the impurity components. The shipping plan creation method according to claim 1.

3. In the voyage pattern creation / selection process, as a term corresponding to the deviation, a value obtained by dividing the magnitude of the difference from the target inventory quantity by the upper limit value of the yard capacity is used as an objective function to select the voyage pattern to be used in the shipping plan. The shipping plan creation method according to claim 1.

4. An operation method for operating a steelworks using the shipping plan formulated by the shipping plan formulation method according to any one of claims 1 to 3.

5. A shipping plan formulation device for formulating a shipping plan including a schedule for transporting raw materials of a plurality of brands by ship from a plurality of loading places to a plurality of unloading places, A data reading unit that reads information including the initial inventory quantity and consumption quantity of each of the plurality of brands at each of the plurality of unloading places, the components of each of the plurality of brands, the upper and lower limit values of the impurity components contained in the raw materials at each of the plurality of unloading places, the upper limit value of the yard capacity at each of the plurality of unloading places, the handling efficiency for each of the berths at the plurality of unloading places, the loadable quantity of each of the plurality of brands at each of the plurality of unloading places, the capacity of the ship, and the transportation cost of the ship; A necessary handling quantity calculation unit that calculates the necessary unloading quantity at each of the plurality of unloading places without considering the restrictions related to the transportation by the ship; A provisional voyage pattern creation unit that creates a provisional voyage pattern by determining the loaded raw materials and loaded quantity at each loading place in the voyage pattern and the unloaded raw materials and unloaded quantity at each unloading place based on the calculation result of the necessary handling quantity calculation unit; A shipping plan formulation device including: a voyage pattern creation / selection unit that creates a plurality of voyage patterns based on the provisional voyage pattern and selects a voyage pattern to be used in the shipping plan from among the plurality of voyage patterns based on the deviation from the target inventory quantity of the inventory of the raw materials, the excess or deficiency from the upper and lower limit values of the impurity components, and the transportation cost.

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