Energy operation support device, energy operation support system, energy operation device, display terminal device, energy operation support method, and steel mill operation method

Abstract

This energy operation support device is an energy operation support device in a steel mill, and is provided with: an optimization unit that optimizes the operation of energy utilities in facilities within the steel mill; and an upper limit relaxation unit that sets an operational upper limit, which is an upper limit on the operation, for a facility upper limit, which is the upper limit of the facility capacity output of the facilities. The upper limit relaxation unit sets a prescribed ratio to the facility upper limit and thereby sets the operational upper limit at a target time or a target calculation period. The objective function of optimization calculation in the optimization unit includes the total energy operation cost of the steel mill and an adjustment parameter for the energy utilities, which have an upper limit equal to the difference between the facility upper limit and the operational upper limit.

Description

Energy operation support device, energy operation support system, energy operation device, display terminal device, energy operation support method, and steelworks operation method

[0001] The present invention relates to an energy management support device, an energy management support system, an energy management device, a display terminal device, an energy management support method, and a method for operating a steelworks.

[0002] Generally, a steelworks is composed of numerous plants and power generation facilities from upstream processes (blast furnaces, coke ovens, steelmaking processes, etc.) to downstream processes (rolling processes, surface treatment processes, etc.), and operates using the following energy sources (gas, steam, and electricity): By-product gases such as B-gas (Blast Furnace gas) generated in the blast furnace, C-gas (Coke Oven gas) generated in the coke oven, and LD-gas (LD converter gas) generated in the converter are used in the plants and power generation facilities. In addition, M-gas (Mixed gas), which is a mixture of these by-product gases and has an adjusted calorific value, is also used in the plants and power generation facilities.

[0003] If the gas supply volume falls short of factory demand (for example, the demand for heating furnaces in a rolling mill), city gas is used to meet the factory demand. Furthermore, if the gas supply volume to a power generation facility falls short of the required volume, heavy oil is used to make up for it. These supplemental fuels incur costs depending on the amount used. Meanwhile, if the gas supply volume exceeds factory demand, the gas is detoxified by combustion and then released into the atmosphere. This should be minimized as it leads to energy loss and carbon dioxide emissions. To reduce costs and prevent emissions, it is necessary to utilize gas holders, which are by-product gas storage facilities, and to appropriately adjust the gas distribution volume.

[0004] For example, in a gas holder, when the supply of by-product gas exceeds the demand, the gas holder stores the by-product gas in preference to dissipation, thereby increasing the storage amount (gas holder level) and suppressing dissipation. On the other hand, when the demand for by-product gas exceeds the supply, the gas holder releases the stored gas to meet demand and reduce the amount of supplemental fuel used. Furthermore, when the demand for by-product gas exceeds the supply, the output of the power generation equipment is reduced. Furthermore, if this does not address the issue, the plant's operating level may be reduced.

[0005] Steam is supplied by sources such as heat recovery boilers from LD gas and sintering furnaces, steam accumulators (steam storage facilities), boilers for CDQ (Coke Drying Quenching), and extraction from the mid-stage turbines of power generation facilities. Steam extraction is the process of obtaining steam from the mid-stage turbine. When steam extraction is performed, the amount of electricity generated by the power generation facilities decreases. Steam is also used in factories (for heat retention of pickling tanks in cold rolling factories and vacuum degassing facilities). Any shortage in steam demand is purchased from outside. The power demand of factories is met by the amount of electricity generated by CDQ, TRT (Top-pressure Recovery Turbine), power generation facilities, and electricity purchased from power companies.

[0006] The amount of electricity purchased must be managed so as not to exceed the hourly contracted amount (maximum electricity purchase amount). Furthermore, since the electricity purchase price varies depending on the time of day, the operating conditions that minimize costs vary depending on the time of day and the supply and demand situation. For example, if the time of day when the price is high and there is a surplus of by-product gas, the output of the power generation equipment must be set high to reduce the amount of electricity purchased. Against this background, technologies to optimize the energy operating costs of steelworks have been proposed.

[0007] For example, Patent Document 1 proposes a method for solving a mixed integer programming problem in which the plant's operating conditions and operating rules are described as constraints by setting upper and lower limits on decision variables in order to find the optimal energy operating conditions of a steelworks.

[0008] Patent No. 7028272

[0009] However, as equipment ages and deteriorates, it becomes difficult to output at the upper limit of the equipment capacity, and so continuing to use the equipment without considering the operational upper limit (hereinafter referred to as the "operational upper limit") that is lower than the equipment upper limit may accelerate the deterioration of the equipment. In addition, when starting up or shutting down equipment due to a shutdown, similar issues must be considered, taking into account the responsiveness of the equipment to the shutdown.

[0010] On the other hand, if the upper limit of the operating capacity is uniformly lowered from the upper limit of the equipment, it will prevent deterioration of the equipment, but it will result in an increase in operating costs. Therefore, it is necessary to minimize operating costs while considering relaxing the upper limit of the operating capacity.

[0011] The present invention has been made in consideration of the above, and aims to provide an energy operation support device, energy operation support system, energy operation device, display terminal device, energy operation support method, and steelworks operation method that can achieve both prevention of equipment deterioration and optimization of operating costs by setting an operating upper limit relative to the equipment upper limit, evaluating operating costs, and relaxing the operating upper limit.

[0012] In order to solve the above-mentioned problems and achieve the objectives, the energy operation support device of the present invention is an energy operation support device for a steelworks, and includes an optimization unit that optimizes the operation of energy utilities in equipment within the steelworks, and an upper limit relaxation unit that sets an operational upper limit, which is an operational upper limit, relative to an equipment upper limit, which is an upper limit on the output of the equipment capacity of the equipment, wherein the upper limit relaxation unit sets the operational upper limit at a target time or a target calculation period by determining a predetermined ratio to the equipment upper limit, and the objective functions of the optimization calculation in the optimization unit include the total energy operation cost of the steelworks and an adjustment variable of energy utilities whose upper limit is the difference between the equipment upper limit and the operational upper limit.

[0013] In addition, in the energy operation support device according to the present invention, in the above invention, the optimization unit performs the optimization calculation under a constraint that the output of the equipment is equal to or less than the sum of the operational upper limit and the adjustment variable.

[0014] In addition, in the energy management support device of the present invention, in the above invention, the objective functions of the optimization calculation in the optimization unit include the total energy management cost and the cost related to the adjustment variable, and the cost related to the adjustment variable is calculated based on the unit price of the energy utility and a predetermined weighting coefficient.

[0015] In the energy management support device according to the present invention, in the above invention, the energy utility is the amount of power generated by a power generation facility, and the unit price of the energy utility is a cost related to the unit price of power purchase.

[0016] In addition, in the above invention, the energy operation support device of the present invention includes a response characteristics calculation unit that calculates an equipment upper limit taking into account the response characteristics of the energy utility during a transition period from shutdown to operation or from operation to shutdown based on an operation shutdown plan for the equipment, and the upper limit relaxation unit sets the operation upper limit using the equipment upper limit taking into account the response characteristics.

[0017] In the energy management support device according to the present invention, in the above invention, the energy utilities include the amount of power generated by the power generation facility, the amount of by-product gas generated, and the amount of steam generated.

[0018] In addition, in the above-described energy operation support device according to the present invention, the device further includes an output unit that outputs information calculated by the optimization unit, including operational conditions for energy utilities in the facility.

[0019] In order to solve the above-mentioned problems and achieve the objectives, the energy operation support system of the present invention is an energy operation support system for a steelworks comprising an energy operation support device and a display terminal device, and comprises: an optimization unit that optimizes the operation of energy utilities in equipment within the steelworks; an upper limit relaxation unit that sets an operational upper limit, which is an operational upper limit, relative to an equipment upper limit, which is the upper limit on the output of the equipment capacity of the equipment; an output unit that outputs information calculated by the optimization unit, including the operational conditions of energy utilities in the equipment; an information acquisition unit that acquires information including the operational conditions of the optimized energy utilities in the equipment; and an information display unit that displays the information acquired by the information acquisition unit, wherein the upper limit relaxation unit sets the operational upper limit at a target time or a target calculation period by determining a predetermined ratio to the equipment upper limit, and the objective functions of the optimization calculation in the optimization unit include the total energy operation cost of the steelworks and an adjustment variable of energy utilities, with the upper limit being the difference between the equipment upper limit and the operational upper limit.

[0020] In addition, in the energy operation support system according to the present invention, in the above invention, the optimization unit performs the optimization calculation under a constraint that the output of the equipment is equal to or less than the sum of the operational upper limit and the adjustment variable.

[0021] In addition, in the energy management support system of the present invention, in the above invention, the objective functions of the optimization calculation in the optimization unit include the total energy management cost and the cost related to the adjustment variable, and the cost related to the adjustment variable is calculated based on the unit price of the energy utility and a predetermined weighting coefficient.

[0022] In the energy management support system according to the present invention, in the above invention, the energy utility is the amount of power generated by a power generation facility, and the unit price of the energy utility is a cost related to the unit price of power purchase.

[0023] In addition, the energy operation support system according to the present invention, in the above invention, includes a response characteristics calculation unit that calculates an equipment upper limit taking into account the response characteristics of the energy utility during a transition period from shutdown to operation or from operation to shutdown based on an operation shutdown plan for the equipment, and the upper limit relaxation unit sets the operation upper limit using the equipment upper limit taking into account the response characteristics.

[0024] In addition, the energy operation support system according to the present invention, in the above invention, includes a tuning screen display unit that sets and displays the specified ratio of the operation upper limit to the equipment upper limit and a weighting coefficient for the cost related to the adjustment variable.

[0025] In order to solve the above-mentioned problems and achieve the objectives, the energy management device of the present invention controls equipment within a steelworks in accordance with the operating conditions of energy utilities output from the output section of the above-mentioned energy management support device.

[0026] In order to solve the above-mentioned problems and achieve the objectives, the energy management device of the present invention controls equipment within a steelworks in accordance with the operating conditions of energy utilities output from the output section of the above-mentioned energy management support system.

[0027] In order to solve the above-mentioned problems and achieve the objectives, the display terminal device of the present invention is a display terminal device that constitutes an energy operation support system in a steelworks, and is equipped with an information acquisition unit that acquires information including the operating conditions of optimized energy utilities in equipment within the steelworks, and an information display unit that displays the information, wherein the information includes the operating conditions of optimized energy utilities in the equipment calculated by an optimization calculation that minimizes an objective function including the cost related to adjustment variables of energy utilities that relax the operating upper limit set for the equipment upper limit on the output of the steelworks' energy equipment, and the total energy operation cost of the steelworks.

[0028] In addition, the display terminal device of the present invention, in the above invention, is provided with a tuning screen display unit that sets and displays a predetermined ratio of the operational upper limit to the equipment upper limit used in the optimization calculation and a weighting coefficient of the cost related to the adjustment variable relative to the total energy operating cost of the steelworks, and the information display unit displays the information calculated by the optimization calculation using the predetermined ratio and the weighting coefficient that are set and displayed on the tuning screen display unit.

[0029] In order to solve the above-mentioned problems and achieve the objectives, the energy operation support method of the present invention includes an optimization step in which an energy operation support device in a steelworks optimizes the operation of energy utilities in equipment within the steelworks, and an operation upper limit setting step in which an operation upper limit is set, which is an operational upper limit, relative to an equipment upper limit, which is an upper limit on the output of the equipment capacity of the equipment, wherein the operation upper limit setting step sets the operation upper limit at a target time or a target calculation period by determining a predetermined ratio to the equipment upper limit, and the optimization calculation in the optimization step includes, as objective functions, the total energy operation cost of the steelworks and an adjustment variable of energy utilities with an upper limit equal to the difference between the equipment upper limit and the operation upper limit.

[0030] In addition, the energy operation support method according to the present invention, in the above invention, includes a response characteristics calculation step in which the energy operation support device calculates an equipment upper limit taking into account the response characteristics of the energy utility during a transition period from shutdown to operation or from operation to shutdown based on an operation shutdown plan for the equipment, and the operation upper limit setting step sets the operation upper limit using the equipment upper limit taking into account the response characteristics.

[0031] In order to solve the above-mentioned problems and achieve the objectives, the method for operating a steelworks of the present invention includes a step of operating the steelworks in accordance with decision variables calculated by the optimization calculation of the above-mentioned energy operation support method.

[0032] The energy management support device, energy management support system, energy management device, display terminal device, energy management support method, and steel mill operation method according to the present invention set an upper operational limit for the equipment upper limit, evaluate operating costs, and relax the upper operational limit, thereby making it possible to prevent equipment deterioration and optimize operating costs at the same time.

[0033] FIG. 1 is a diagram illustrating a schematic configuration of an energy management support system according to an embodiment of the present invention. FIG. 2A is a diagram illustrating a schematic configuration of an information processing device implementing the energy management support device according to an embodiment of the present invention, and FIG. 2B is a diagram illustrating a schematic configuration of a display terminal device according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating a flow of an energy management support method executed by the energy management support device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of response characteristics when a response transition process during a transition period from equipment shutdown to operation is represented by a straight line and an exponential function (first-order lag) in the response characteristic calculation step of the energy management support method according to an embodiment of the present invention. FIG. 5 is a diagram illustrating an example of an equipment upper limit when a response transition process during a transition period from equipment shutdown to operation is represented by a straight line and an exponential function (first-order lag) in the response characteristic calculation step of the energy management support method according to an embodiment of the present invention. FIG. 6 is a diagram illustrating a normalized output (the value obtained by dividing the power generation output by the equipment upper limit and multiplying the result by 100) obtained by optimization calculation when a predetermined ratio of a certain power generation facility to the equipment upper limit is 0.5 and the weight of the adjustment variable is 0.01, according to an example of the present invention. FIG. 7 is a diagram showing a cost ratio (operating cost with relaxation / operating cost without relaxation) calculated by setting a predetermined ratio of a power generation facility to its upper limit in 0.1 increments from 0.1 to 1.0 and setting the weight of the adjustment variable to 0.01, according to an embodiment of the present invention. FIG. 8 is a diagram showing a normalized output (the value obtained by dividing the power generation output by the upper limit and multiplying the result by 100) obtained by optimizing the ratio of a power generation facility to its upper limit in 0.5 and setting the weight of the adjustment variable to 0.01, taking into account the response characteristics during the transition period from the facility's shutdown to its operation. FIG. 9 is a diagram showing a cost ratio (operating cost with relaxation / operating cost without relaxation) calculated by setting a predetermined ratio of a power generation facility to its upper limit in 0.1 increments from 0.1 to 1.0 and setting the weight of the adjustment variable to 0.01, according to an embodiment of the present invention.

[0034] An energy management support device, an energy management support system, an energy management device, a display terminal device, an energy management support method, and a steelworks operation method according to embodiments of the present invention will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable by a person skilled in the art, or those that are substantially identical.

[0035] (Energy Operation Support System) An energy operation support system including an energy operation support device according to an embodiment will be described with reference to Fig. 1. The energy operation support system is a system used in, for example, a steelworks, and calculates optimal energy operation conditions (conditions related to the operation of energy utilities) in the steelworks. As shown in the figure, the energy operation support system 1 includes an information processing device 10, an operation plan and performance database 20, and a display terminal device 30. The energy utilities include, for example, gas, steam, and electricity.

[0036] The information processing device 10, the operation plan and performance database 20, and the display terminal device 30 are configured to be able to communicate with each other via a network N such as the Internet. In the energy management support system, the display terminal device 30 is installed in, for example, a steelworks.

[0037] (Energy Management Assistance Apparatus) An information processing apparatus 10 that realizes an energy management assistance apparatus according to an embodiment will be described with reference to (a) in FIG. 2. The information processing apparatus 10 is realized by, for example, a general-purpose computer such as a workstation or a personal computer, or a server located on a cloud. The information processing apparatus 10 may be configured by multiple computers connected via a network. The information processing apparatus 10 may also include information input means such as a keyboard, a mouse pointer, or a numeric keypad.

[0038] The information processing device 10 includes a processor (arithmetic processing device) such as a CPU (Central Processing Unit) and a memory (main storage unit) such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The processor executes a computer program to control each component, thereby realizing functions that meet a predetermined purpose. The information processing device 10 functions as a response characteristic calculation unit 11, an upper limit relaxation unit 12, and an optimization unit 13 through the execution of the computer program.

[0039] The information processing device 10 may also include a storage unit that stores various processing results, etc. This storage unit may be configured with a recording medium such as an erasable programmable read-only memory (EPROM), a hard disk drive (HDD), a solid state drive (SSD), or a removable medium. Examples of removable media include a universal serial bus (USB) memory, a compact disc (CD), a digital versatile disc (DVD), and a Blu-ray (registered trademark) disc (BD).

[0040] The response characteristics calculation unit 11 calculates an equipment upper limit taking into account the response characteristics of the energy utility during a transition period from shutdown to operation or a transition period from operation to shutdown, based on the energy equipment operation shutdown plan. Specific processing details of the response characteristics calculation unit 11 will be described later (see FIGS. 3 to 5 ). The processing of the response characteristics calculation unit 11 may be performed immediately before the processing of the upper limit relaxation unit 12 and the optimization unit 13, or may be performed in advance at a timing different from the processing of the upper limit relaxation unit 12 and the optimization unit 13.

[0041] The upper limit alleviation unit 12 sets an operational upper limit, which is an operational upper limit, relative to an equipment upper limit, which is an upper limit on the output of the equipment capacity of the energy equipment. The upper limit alleviation unit 12 sets an operational upper limit at a target time or a target calculation period by determining a predetermined ratio to the equipment upper limit. Furthermore, the upper limit alleviation unit 12 may set the operational upper limit using an equipment upper limit that takes into account the response characteristics calculated by the response characteristics calculation unit 11, or may set the operational upper limit without using an equipment upper limit that takes into account the response characteristics. Specific processing details of the upper limit alleviation unit 12 will be described later (see FIG. 3, described later).

[0042] The optimization unit 13 optimizes the operation of energy utilities in the energy facilities within the steelworks. The optimization unit 13 obtains information on energy utilities for each plant that makes up the steelworks and information on the operation plan of the energy facilities within the steelworks from the operation plan / performance database 20, and performs optimization calculations.

[0043] Here, "information related to energy utilities" includes actual and predicted values ​​of the amount of energy utility generation, actual and predicted values ​​of the amount of energy utility consumption, etc. Furthermore, "energy utilities" include, for example, electricity (amount of power generated by power generation facilities), gas (amount of by-product gas generated), and steam (amount of steam generated). Furthermore, "information related to the operation plan of energy facilities" includes, for example, energy facility settings and contract values ​​of trading contracts. Furthermore, "energy facilities" include, for example, mixed gas production facilities, gas holders, steam accumulators, blast furnace top pressure power generation facilities, and power generation facilities that use by-product gas, heavy oil, or extracted steam. Furthermore, "trading contracts" include, for example, purchase contracts for the use of heavy oil, city gas, and steam, and purchase contracts for purchasing electricity.

[0044] The objective function of the optimization calculation in the optimization unit 13 is the total energy operation cost of the steelworks (total_cost(k)) and the adjustment variable of the energy utility (dSUB POW　j (k)) (see Equation (17) below). In more detail, the above-mentioned objective variables include the total energy operation cost of the steelworks (total_cost(k)) and the cost related to the adjustment variables of the energy utilities (wP ELE(k)dSUB POW　j (k)) are included.

[0045] Here, "total energy operating costs" include, for example, costs associated with the use of heavy oil, city gas, and steam, as well as costs associated with purchasing electricity. The "adjustment variable" is a variable for adjusting output to relax the operating upper limit, and is a variable for adjusting the degree to which the operating upper limit is changed. This adjustment variable has a lower limit of 0 and an upper limit of the difference between the equipment upper limit and the operating upper limit (see Equation (15) below). The "costs related to the adjustment variable" are costs calculated based on the unit price of energy utilities and a predetermined weighting coefficient (see Equation (17) below). The "unit price of energy utilities" includes, for example, costs related to the unit price of electricity purchase, the unit price of steam purchase, the unit price of heavy oil purchase, and the unit price of city gas purchase.

[0046] The optimization unit 13 transmits information such as the results of optimization calculations to other terminal devices and other information processing devices via the network N. Note that the specific processing content of the optimization unit 13 will be described later (see FIG. 3).

[0047] The information processing device 10 may include an output unit 14 that transmits various information to other terminal devices or other information processing devices via the network N. The output unit 14 outputs information calculated by the optimization unit 13, including, for example, the operating conditions of energy utilities in facilities in the steelworks. Specific examples of the information transmitted by the output unit 14 include the operating conditions of energy utilities in facilities in the steelworks (energy operating conditions) that are included in the decision variables (see Tables 4 and 5) calculated by the optimization calculation by the optimization unit 13.

[0048] Furthermore, the other information processing devices to which the output unit 14 transmits various information may include, for example, a control computer for each energy facility. This control computer may control each energy facility according to the transmitted operating conditions of the energy facility. The control computer may also control each energy facility by accepting modifications by an operating operator. Here, examples of control of energy facilities include increasing the output of a power generation facility to reduce the amount of electricity purchased during times when the electricity purchase price is high, and discharging gas stored in a gas holder to increase the output of the power generation facility.

[0049] The output unit 14 may also display the various pieces of information through a display device (e.g., a liquid crystal display (LCD), an organic light-emitting diode (OLED), a touch panel display, etc.) not shown connected to the information processing device 10. The output unit 14 may also display a tuning screen or the like for various calculations performed by the optimization unit 13. The output unit 14 may also be configured as a display device and display the various pieces of information, the tuning screen, etc.

[0050] The tuning screen may display, for example, a predetermined ratio Ratio (see formulas (14) and (15) described later) to the operational upper limit of the energy equipment included in the constraint conditions in the optimization calculation of the optimization unit 13. The tuning screen may also display, for example, a weighting coefficient w (see formula (17) described later) that is predetermined for the "cost related to the adjustment variable."

[0051] (Operation Plan and Performance Database) The operation plan and performance database 20 is stored in a storage device that is configured from a recording medium such as an EPROM (Erasable Programmable ROM), a hard disk drive (HDD), or a removable medium.

[0052] The operation plan / performance database 20 stores information relating to the steelworks' operation plan (hereinafter referred to as "operation plan information") and information relating to the operation performance (hereinafter referred to as "operation performance information"). The operation plan information and the operation performance information are accumulated, for example, by an operation planning device and an operation performance device (not shown), and then aggregated by an aggregation device (not shown) and stored in the operation plan / performance database 20. The operation plan / performance database 20 may also be configured by a database server provided on the network N.

[0053] (Display Terminal Device) The display terminal device 30 is for acquiring and displaying various information from the information processing device 10. This display terminal device 30 is realized, for example, by a personal computer connected to the information processing device 10 via a network N. Furthermore, as shown in FIG. 2(b), the display terminal device 30 has, for example, the function of an information acquisition unit 31 and the function of an information display unit 32.

[0054] The information acquisition unit 31 acquires information such as the results of optimization calculations from, for example, the information processing device 10, and displays the information on a display device (information display unit) (not shown) connected to the display terminal device 30. The display terminal device 30 may also be configured by a display device, and may display information such as the results of optimization calculations acquired from the information processing device 10 via the network N.

[0055] The information acquisition unit 31 acquires information including optimized operating conditions of energy utilities in facilities within the steelworks from the information processing device 10. Furthermore, the information display unit 32 displays the information acquired by the information acquisition unit 31.

[0056] The information displayed by the information display unit 32 includes, for example, optimized energy utility operating conditions for the equipment calculated by an optimization calculation that minimizes an objective function including the costs associated with adjustment variables for energy utilities that relax an operational upper limit set for an equipment upper limit on the output of energy equipment at a steelworks, and the total energy operating cost of the steelworks. For example, the information includes an operational upper limit, which is an upper limit on the operation of equipment at a steelworks, determined by a predetermined ratio to the equipment upper limit, which is an upper limit on the output of the equipment capacity of the equipment, and an energy utility adjustment variable, whose upper limit is the difference from the equipment upper limit. The information displayed by the information display unit 32 also includes, for example, costs associated with the adjustment variables calculated based on the total energy operating cost of the steelworks, the unit price of the energy utility, and a predetermined weighting coefficient. The information displayed by the information display unit 32 also includes optimized energy utility operating conditions (energy operating conditions) for the equipment calculated by an optimization calculation based on, for example, a constraint that the equipment output be equal to or less than the sum of the operational upper limit and the adjustment variable.

[0057] The information display unit 32 displays at least the total energy operating cost, the operating upper limit, and the adjustment variables of the steelworks. The information display unit 32 may also display the total energy operating cost of the steelworks, the operating upper limit of energy utilities, and the adjustment variables included in the information of the results of the optimization calculation.

[0058] The display terminal device 30 may include a tuning screen display unit 33 that displays a tuning screen during optimization calculation. The tuning screen display unit 33 may set and display, for example, a predetermined ratio Ratio (see Equations (14) and (15) described below) to the operational upper limit of the energy equipment included in the constraint conditions in the optimization calculation of the optimization unit 13. Furthermore, the tuning screen display unit 33 may set and display, for example, a predetermined weighting coefficient w (see Equation (17) described below) for the "cost related to the adjustment variable."

[0059] In addition, when the display terminal device 30 is equipped with a tuning screen display unit 33, the information display unit 32 may display information including optimized energy operation conditions for equipment within the steelworks, calculated by optimization calculation using a predetermined ratio Ratio set and displayed on the tuning screen display unit 33 and a weighting coefficient w.

[0060] Note that the configurations shown in Figures 1 and 2(a) and (b) are examples. The information processing device 10 and the display terminal device 30 may not include all of the components shown in Figures 2(a) and (b), respectively. Furthermore, the information processing device 10 and the display terminal device 30 may include components other than the components shown in Figures 2(a) and (b), respectively. Furthermore, the components included in the information processing device 10 and the display terminal device 30 are not limited to the examples shown in Figures 2(a) and (b), respectively.

[0061] For example, the optimization unit 13 and the information display unit 32 may be in the same device. Furthermore, for example, some of the components included in the information processing device 10 in (a) of Fig. 2 may be provided on the display terminal device 30 side. Furthermore, for example, some of the components included in the display terminal device 30 in (b) of Fig. 2 may be provided on the information processing device 10 side. Therefore, an energy management support system including the information processing device 10 and the display terminal device 30 may include the response characteristics calculation unit 11, the upper limit alleviation unit 12, the optimization unit 13, the output unit 14, the information acquisition unit 31, and the information display unit 32 as a whole.

[0062] (Energy Management Device) The energy management device according to the embodiment controls the steelworks equipment (energy equipment) in accordance with the optimized energy utility operation conditions (energy operation conditions) of the steelworks equipment output from the output unit 14 of the energy management support system 1 (information processing device 10). The energy management device is realized, for example, by a control computer for each energy equipment. Examples of control of the energy equipment include increasing the output of the power generation equipment so that the amount of purchased electricity does not exceed the contracted amount per hour (upper limit of purchased electricity), and discharging stored gas from a gas holder to increase the output of the power generation equipment.

[0063] (Energy Management Support Method) The energy management support method executed by the energy management support system according to the embodiment will be described with reference to Figures 3 to 5. As shown in the figures, the energy management support method includes a response characteristics calculation step (steps S1 to S3), an upper limit relaxation step (steps S4 to S6), and an optimization step (steps S7 to S9).

[0064] 3 starts when an instruction to execute the optimization calculation process is input to the information processing device 10, and the optimization calculation process proceeds to step S1. Steps S1 to S3 may be performed immediately before steps S4 to S9, or may be performed in advance at a different timing from steps S4 to S9.

[0065] <Steps S1 to S3> In the process of step S1, the response characteristic calculation unit 11 reads the response characteristics. This response characteristic is an approximation of the response transition process as a straight line or an exponential function (first-order lag) during the transition period from the shutdown of the equipment (energy equipment) to operation, or during the transition period from operation to shutdown of the equipment. For example, (a) in FIG. 4 shows an example of the response characteristic when the response transition process is approximated as a straight line. Also, (b) in the same figure shows an example of the response characteristic when the response transition process is approximated as an exponential function (first-order lag). Note that in the same figure, the equipment upper limit during operation is illustrated as the "equipment upper limit during steady state." Meanwhile, during the transition time from shutdown to operation, the line indicated by A in the same figure is the equipment upper limit.

[0066] Next, in the process of step S2, the response characteristic calculation unit 11 calculates the equipment upper limit taking the response characteristics into consideration. Specifically, if the target time or target calculation period is a transition period from equipment shutdown to operation or from operation to shutdown, the response characteristic calculation unit 11 calculates the equipment upper limit for each time or each calculation period according to the response characteristics. Note that if the target time or target calculation period is not a transition period, a predetermined value that does not take the response characteristics into consideration is set as the equipment upper limit.

[0067] 5 shows an example of the equipment upper limit when the transition process of the response during the transition period (transition time) from equipment shutdown to operation is expressed as a straight line and an exponential function (first-order lag). The slope of the straight line is expressed as "equipment upper limit when equipment is operating / transition period from equipment shutdown to operation." Furthermore, the exponential function is expressed as "first-order lag based on a time constant (e.g., the time required to reach 63% of the equipment upper limit)."

[0068] Next, in the process of step S3, the upper limit of the equipment (for example, the upper limit of the power generation amount UB ) is calculated taking into account the response characteristics calculated in the process of step S2. POW　X The upper limits of the equipment taking into consideration the response characteristics are stored in advance as a list of set values, so that the operator can view them.

[0069] <Steps S4 to S6> In the process of step S4, the upper limit alleviation unit 12 reads a predetermined ratio related to the operation upper limit and the adjustment variable upper limit. This "predetermined ratio" is a ratio for calculating the operation upper limit with respect to the equipment upper limit, and is a ratio for determining the operation upper limit for preventing equipment deterioration from the equipment upper limit. The specific value of the predetermined ratio is not limited, and a value determined in advance according to the characteristics of each equipment is used.

[0070] Next, in the processing of step S5, the upper limit alleviation unit 12 calculates the operation upper limit and the adjustment variable upper limit. The operation upper limit can be calculated by multiplying the equipment upper limit by a predetermined ratio. That is, "operation upper limit = equipment upper limit × predetermined ratio". Also, the adjustment variable upper limit can be calculated by subtracting the operation upper limit from the equipment upper limit. That is, "adjustment variable upper limit = equipment upper limit - operation upper limit = equipment upper limit × (1 - predetermined ratio)".

[0071] Next, in the process of step S6, the operational upper limit and the adjustment variable upper limit calculated in the process of step S5 are stored in the operation plan and performance database 20.

[0072] <Steps S7 to S9> In the process of step S7, the optimization unit 13 performs optimization calculations. First, the optimization unit 13 acquires data on the setting values ​​of the energy facilities in the steelworks as input data for the optimization calculation process. This setting value data includes the following, as shown in Table 1, for example. In Table 1, "x" indicates the number of generators.

[0073] Power generation upper limit (x=1U to NU): UB POW　X Power generation lower limit (x=1U to NU): LB POW　X Power generation change upper limit (x=1U to NU): UB POWDIF　X Power generation change lower limit (x=1U to NU): LB POWDIF　X B gas holder upper limit (storage capacity): UB B　LEVEL B Gas Holder Lower Limit (Storage Amount): LB B　LEVEL B Gas holder upper limit (intake amount / discharge amount): UB B　INOUT B Gas holder lower limit (intake amount / discharge amount): LB B　INOUT C gas holder upper limit (storage capacity): UB C　LEVEL C gas holder lower limit (storage capacity): LB C　LEVEL C Gas holder upper limit (intake amount / discharge amount): UB C　INOUT C Gas holder lower limit (intake amount / discharge amount): LB C　INOUT LD gas holder upper limit (storage capacity): UB LD　LEVEL LD gas holder lower limit (storage capacity): LB LD　LEVEL LD gas holder upper limit (intake amount / discharge amount): UB LD　INOUT LD gas holder lower limit (intake amount / discharge amount): LB LD　INOUT Steam accumulator upper limit (storage capacity): UB ST　LEVEL Steam accumulator lower limit (storage volume): LB ST　LEVEL Steam accumulator upper limit (intake / discharge amount): UB ST　INOUT Steam accumulator lower limit (intake / discharge amount): LB ST　INOUT Predetermined ratio: Ratio Weight of adjustment variable: w

[0074]

[0075] The optimization unit 13 also acquires contract value data necessary for calculating the costs of energy operation at the steelworks as input data for the optimization calculation process. This contract value data includes the following, as shown in Table 2, for example. In Table 2, "k = 0" indicates the present, and "k = 1 to N" indicate the future. "N" is the final period of the optimization calculation, and indicates two hours into the future, for example, when N = 24 and one period is in 5-minute increments.

[0076] Electricity purchase price: P ELE (k) Steam purchase price: P ST (k) Heavy oil purchase price: P OIL (k) City gas purchase price: P TOG (k)

[0077]

[0078] The optimization unit 13 also acquires data on the actual values ​​of energy utilities in the steelworks at the current time (k=0) as input data for the optimization calculation process. This data on actual values ​​includes the following, as shown in Tables 3 to 5 (see the second column from the left), for example.

[0079] B gas generation amount (factory total): S B (0) C gas generation amount (factory total): S C (0) LD gas generation amount (factory total): S LD (0) Steam generation (factory total): S ST (0) TRT power generation (total units): S TRTELE (0) Power generation capacity of power generation facility (x=1U to NU): S POW　X (0) B gas usage (factory total): D B (0) C gas consumption (factory total): D C (0) LD gas consumption (factory total): D LD (0) M gas consumption (factory total): D M　PLANT (0) Steam consumption (factory total): D ST (0) Electricity consumption (factory total): D ELE (0) B gas usage (x=1U to NU): D B X (0) C gas consumption (x=1U to NU): D C ​​X (0) LD gas consumption (x=1U to NU): D LD X (0) M gas consumption (x=1U to NU): D M X (0) Heavy oil consumption (x=1U~NU): D OIL X (0) Bleed air amount (x=1U~NU): S ST X (0) City gas consumption (for power generation facilities): D TOG　POW (0) City gas consumption (for factories (rolling)): D TOG　Mill (0) B Gas Holder (storage capacity): H B　LEVEL (0) B gas holder (intake and discharge amount): H B INOUT (0) C Gas Holder (storage capacity): H C　LEVEL (0) C gas holder (intake and discharge amount): H C INOUT (0) LD gas holder (storage capacity): H LD　LEVEL (0) LD gas holder (intake and discharge amount): H LD INOUT (0) Steam accumulator (storage capacity): H ST　LEVEL (0) Steam accumulator (intake and discharge volume): H ST　INOUT (0) Power purchase amount: S ELE　Purchase (0) Steam purchase amount: S ST　Purchase (0) M gas (B gas) for power generation facilities: D B　POW (0) M gas (C gas) for power generation facilities: D C　POW (0) M gas (LD gas) for power generation equipment: D LD　POW (0) M gas (city gas) for power generation facilities: D TOG　POW (0) Factory Gas M (Gas B): D B　Mill (0) Factory M Gas (C Gas): D C　Mill (0) Factory M Gas (LD Gas): D LD　Mill (0) Industrial M Gas (City Gas): D TOG　Mill (0) Total energy operating cost: total_cost(0) Adjustment variable: dSUB POW　j (0)

[0080] ​​​​​​​

[0081] The optimization unit 13 also acquires data on predicted values ​​of energy utilities of factories in the steelworks in the future (k = 1 to N) as input data for the optimization calculation process. This predicted value data includes, for example, the following, as shown in Table 3 above (see the third column from the left):

[0082] B gas generation amount (factory total): S B (k) C gas generation amount (factory total): S C (k) LD gas generation amount (factory total): S LD (k) Steam generation (factory total): S ST (k) TRT power generation (all units): S TRTELE (k) Power generation capacity of power generation facility (x=1U to NU): S POW　X (k) B gas consumption (factory total): D B (k) C gas consumption (factory total): D C (k) LD gas consumption (factory total): D LD (k) M gas consumption (factory total): D M　PLANT (k) Steam consumption (factory total): D ST (k) Electricity consumption (factory total): D ELE (k)

[0083] Next, in the processing of step S7, using the data acquired as described above, an optimization calculation is performed to determine the conditions for minimizing the total energy operating cost total_cost(k) for the steelworks' energy operations within a predetermined future period (k = 1 to N).

[0084] The decision variables (variables searched to minimize cost) in the optimization calculation in step S7 include the following, as shown in Tables 4 and 5 above (see the third column from the left):

[0085] B gas usage (x=1U to NU): D B X (k) C gas consumption (x = 1U to NU): D C X (k) LD gas consumption (x = 1U to NU): D LD X (k) M gas consumption (x = 1U to NU): D M ​​​​X (k) Heavy oil consumption (x=1U~NU): D OIL X (k) Bleed air amount (x=1U~NU): S ST X (k) City gas consumption (for power generation): D TOG　POW (k) City gas consumption (for factories (rolling)): D TOG　Mill (k) B Gas Holder (storage capacity): H B　LEVEL (k) B gas holder (intake and discharge amount): H B INOUT (k) C Gas Holder (storage capacity): H C　LEVEL (k) C gas holder (intake and discharge amount): H C INOUT (k) LD gas holder (storage capacity): H LD　LEVEL (k) LD gas holder (intake and discharge amount): H LD INOUT (k) Steam accumulator (storage capacity): H ST　LEVEL (k) Steam accumulator (intake and discharge volume): H ST　INOUT (k) Power purchase amount: S ELE　Purchase (k) Steam purchase amount: S ST　Purchase (k) M gas (B gas) for power generation facilities: D B　POW (k) M gas (C gas) for power generation facilities: D C　POW (k) M gas (LD gas) for power generation facilities: D LD　POW (k) M gas (city gas) for power generation facilities: D TOG　POW (k) Industrial Gas M (Gas B): D B　Mill (k) Industrial Gas M (Gas C): D C　Mill (k) Industrial M Gas (LD Gas): D LD　Mill (k) M gas for factories (city gas): D TOG　Mill (k) Total energy operating cost: total_cost(k) Adjustment variable: dSUB POW　j (k)

[0086] ​​​​​In step S7, constraint conditions are set as shown in the following formulas (1) to (15) during optimization calculation. Note that "T" in the following formulas (6) and (11) is the time equivalent value of one period, and for example, if one period is equal to 5 minutes, then T = 5 / 60 (h). Also, the subscript "j" in the following formulas (1) to (15) indicates the number of the energy facility (for example, a generator). That is, "f ｊ " is a function indicating the power generation characteristics of the generator j, and for example, inputs the amount of by-product gas generated or the amount of steam generated and outputs the amount of power generated.

[0087] Here, the following formula (1) represents the B gas balance. The following formula (2) represents the C gas balance. The following formula (3) represents the LD gas balance. The following formula (4) represents the M gas balance of the factory. The following formula (5) represents the M gas balance of the power generation facility. The following formula (6) represents the gas holder. The following formula (7) represents the power generation model. The following formula (8) represents the power balance. The following formula (9) represents the steam balance. The following formulas (10) to (15) represent the upper and lower limit balances.

[0088] In addition, the following formula (14) is specifically a constraint condition that the output of the energy facility is equal to or greater than the lower limit of the energy facility and equal to or less than the sum of the operation upper limit and the adjustment variable. In the following formula (14), the energy facility is a power generation facility, and the power generation amount of the power generation facility (S POW　X (k)) is the power generation lower limit (LB POW　j ) or more, and the sum of the operating upper limit and the adjustment variable (RatioUB POW j +dSUB POW j (k)), but the same applies to the amount of by-product gas or steam generated.

[0089] In addition, the following formula (15) specifically includes the adjustment variable (dSUB POW j The constraints are the lower and upper limits of the adjustment variable (dSUB(k)). POW ​​​​j (k)) has a lower limit of 0 and an upper limit of "(1-Ratio)UB POW x(k) is a real number.

[0090]

[0091] The total energy operating cost total_cost(k) to be minimized in step S7 is the sum of the supplementary fuels, heavy oil (OIL), city gas (TOG), steam (ST), and purchased electricity (ELE), as shown in the following formula (16). The unit prices of each are as shown in Table 2 above.

[0092]

[0093] Using these, the sum of the total cost from the current time to N cycles ahead and the cost related to the adjustment variable (apparent cost for the adjustment variable) is calculated as shown in the following formula (17). As shown in the following formula (17), an apparent cost occurs for the amount of power generation that exceeds the operational upper limit, and since it is multiplied by the weight w, it becomes cheaper than the power purchase cost, and when power is purchased, the power generation facility generates power in excess of the operational upper limit. In the following formula (17), since the adjustment variable corresponds to power, the power purchase unit price (P ELE However, if the adjustment variables correspond to steam, heavy oil, or city gas, the unit purchase price of steam, heavy oil, or city gas may also be used.

[0094]

[0095] Next, in the process of step S8, the optimization unit 13 displays the results of the optimization calculation on, for example, the display terminal device 30. Next, in the process of step S9, the optimization unit 13 determines whether or not the optimization calculation has been completed, and if so, ends this process, and if not, returns to the process of step S1.

[0096] (Method for operating a steelworks) The method for operating a steelworks according to the embodiment includes a step of operating the steelworks in accordance with the decision variables (see Tables 4 and 5) calculated by the optimization calculation of the above-described method for supporting energy operation in a steelworks. As a result, the method for operating a steelworks according to the embodiment can minimize the energy operation costs of the steelworks by setting an upper limit on operation for equipment related to energy utilities in the steelworks to avoid equipment deterioration and relaxing the upper limit in accordance with the operation costs.

[0097] In the energy management support device, energy management support system, energy management device, display terminal device, energy management support method, and steelworks operation method according to the above-described embodiments, an output adjustment variable is introduced whose upper limit is the difference between the equipment upper limit and the operation upper limit, and the sum of the adjustment variable and the operation upper limit is set as the output upper limit, thereby relaxing the operation upper limit. Furthermore, the objective function of the optimization calculation includes the apparent power generation cost (the power purchase price multiplied by a weight), which is set to be cheaper than the power purchase price, resulting in a mechanism for generating power in excess of the operation upper limit instead of refraining from purchasing power. The same applies when considering the response characteristics during the transition period from shutdown to operation, or from operation to shutdown.

[0098] As described above, in the energy management support device, energy management support system, energy management device, display terminal device, energy management support method, and steelworks operation method according to the embodiments, in order to relax the upper limit of the operation of energy equipment, an adjustment variable is taken into account in addition to the upper limit of the operation, and an upper limit of energy utilities is set to allow up to the upper limit of the equipment. This makes it possible to minimize operating costs while taking into account the relaxation of the upper limit of the operation. Furthermore, when starting up or shutting down energy equipment due to a shutdown, the upper limit of the equipment is set to change gradually taking into account the response characteristics, and in this case as well, the same effect as described above is expected.

[0099] In this way, the energy operation support device, energy operation support system, energy operation device, display terminal device, energy operation support method, and steel mill operation method according to the embodiments set an upper operational limit for the equipment upper limit, evaluate operating costs, and relax the upper operational limit, thereby making it possible to prevent equipment deterioration and optimize operating costs at the same time.

[0100] An example of the energy management support method according to the present invention will be described with reference to Figures 6 to 9. In this example, optimization calculations were performed for up to 24 cycles ahead, with one cycle being 5 minutes, and the calculation results were displayed on a display terminal device.

[0101] In Example 1, the upper limit relaxation step and the optimization step were performed during the time period when the power generation facility was in operation. In Example 1, the response characteristics during the transition period from operation to shutdown or from shutdown to operation were not taken into consideration.

[0102] 6 shows the normalized output (the value obtained by dividing the power generation output by the facility upper limit and multiplying the result by 100) obtained by optimization calculations in which the predetermined ratio of a certain power generation facility to its facility upper limit is set to 0.5 and the weight of the adjustment variable is set to 0.01. As shown in the figure, it can be seen that the normalized output increases with upper limit relaxation (see solid line) compared to the case without upper limit relaxation (see dashed line).

[0103] Next, Figure 7 shows the cost ratio (operating cost with relaxation / operating cost without relaxation) calculated by setting the predetermined ratio of the facility upper limit of a certain power generation facility to 0.1 in 0.1 increments from 0.1 to 1.0 and setting the weight of the adjustment variable to 0.01. As shown in the figure, it can be seen that the operating cost with upper limit relaxation is reduced according to the predetermined ratio. In particular, when the predetermined ratio is less than 0.4, the operating cost with upper limit relaxation is reduced by 20%.

[0104] In the second embodiment, upper limit relaxation and optimization were performed in consideration of the response characteristics of the power generation equipment during a time period including a transition period from shutdown to operation.

[0105] Figure 8 shows the normalized output (the value obtained by dividing the power generation output by the facility upper limit and multiplying the result by 100) when optimizing a certain power generation facility with a predetermined ratio of the facility upper limit set to 0.5 and a weight of the adjustment variable set to 0.01. As shown in the figure, when the upper limit is relaxed (see the solid line), power is generated according to the response characteristics during the transition period from shutdown to operation in order to avoid purchasing electricity as much as possible. On the other hand, when the upper limit is not relaxed (see the dashed dotted line), output is suppressed to comply with the operational upper limit.

[0106] The cost ratio (operating cost with relaxation / operating cost without relaxation) calculated by setting the predetermined ratio of a certain power generation facility to the facility upper limit in 0.1 intervals from 0.1 to 1.0 and setting the weight of the adjustment variable to 0.01 is shown in Figure 9. As shown in the figure, the operating cost does not change significantly even when the predetermined ratio is changed, but when the predetermined ratio is less than 0.4, the operating cost with upper limit relaxation is reduced by just under 10%.

[0107] In this way, the energy management support device, energy management support system, energy management device, display terminal device, energy management support method, and steel mill operation method of the present invention make it possible to set an upper limit on operations to avoid equipment deterioration, and to minimize operating costs while relaxing the upper limit in accordance with operating costs.

[0108] The energy management support device, energy management support system, energy management device, display terminal device, energy management support method, and steelworks operation method according to the present invention have been specifically described above using the preferred embodiments and examples, but the scope of the present invention is not limited to these descriptions and should be broadly interpreted based on the claims. Furthermore, it goes without saying that various changes and modifications based on these descriptions are also included in the scope of the present invention.

[0109] DESCRIPTION OF SYMBOLS 1 Energy operation support system 10 Information processing device 11 Response characteristic calculation unit 12 Upper limit relaxation unit 13 Optimization unit 14 Output unit 20 Operation plan / performance database 30 Display terminal device 31 Information acquisition unit 32 Information display unit 33 Tuning screen display unit N Network

Claims

1. An energy operations support device in a steelworks, comprising: an optimization unit that optimizes the operation of energy utilities in equipment within the steelworks; and an upper limit relaxation unit that sets an operational upper limit, which is an upper limit on operation, relative to an equipment upper limit, which is an upper limit on the output of the equipment capacity of the equipment, wherein the upper limit relaxation unit sets the operational upper limit at a target time or target calculation period by determining a predetermined ratio to the equipment upper limit, and the optimization calculation in the optimization unit includes, as objective functions, a total energy operations cost of the steelworks and an adjustment variable for energy utilities whose upper limit is the difference between the equipment upper limit and the operational upper limit.

2. An energy operation support device as described in claim 1, wherein the optimization unit performs the optimization calculation under the constraint that the output of the equipment is equal to or less than the sum of the operational upper limit and the adjustment variable.

3. The energy operation support device of claim 1, wherein the total energy operation cost and a cost related to the adjustment variable are included as objective functions of the optimization calculation in the optimization unit, and the cost related to the adjustment variable is calculated based on the unit price of the energy utility and a predetermined weighting coefficient.

4. The energy operation support device according to claim 3, wherein the energy utility is the amount of power generated by a power generation facility, and the unit price of the energy utility is a cost related to the unit price of electricity purchase.

5. The energy operation support device of claim 1, further comprising a response characteristics calculation unit that calculates an equipment upper limit taking into account the response characteristics of the energy utility during a transition period from shutdown to operation or from operation to shutdown based on an operation shutdown plan for the equipment, and the upper limit mitigation unit sets the operation upper limit using the equipment upper limit taking into account the response characteristics.

6. An energy operation support device as described in claim 1, wherein the energy utilities include the amount of electricity generated by the power generation facility, the amount of by-product gas generated, and the amount of steam generated.

7. The energy operation support device according to claim 1, further comprising an output unit that outputs information calculated by the optimization unit, including operational conditions of energy utilities in the facility.

8. An energy operations support system in a steelworks comprising an energy operations support device and a display terminal device, comprising: an optimization unit that optimizes the operation of energy utilities in equipment in the steelworks; an upper limit relaxation unit that sets an operational upper limit, which is an operational upper limit, against an equipment upper limit, which is an upper limit on the output of the equipment capacity of the equipment of the equipment; an output unit that outputs information calculated by the optimization unit including operational conditions of energy utilities in the equipment; an information acquisition unit that acquires information including the operational conditions of the optimized energy utilities in the equipment; and an information display unit that displays the information acquired by the information acquisition unit, wherein the upper limit relaxation unit sets the operational upper limit at a target time or target calculation period by determining a predetermined ratio with respect to the equipment upper limit, and the objective function of the optimization calculation in the optimization unit includes a total energy operations cost of the steelworks and an adjustment variable of energy utilities with an upper limit equal to the difference between the equipment upper limit and the operational upper limit.

9. An energy operation support system as described in claim 8, wherein the optimization unit performs the optimization calculation under the constraint that the output of the equipment is equal to or less than the sum of the operational upper limit and the adjustment variable.

10. The energy operation support system of claim 8, wherein the total energy operation cost and a cost related to the adjustment variable are included as objective functions of the optimization calculation in the optimization unit, and the cost related to the adjustment variable is calculated based on the unit price of the energy utility and a predetermined weighting coefficient.

11. The energy operation support system according to claim 10, wherein the energy utility is the amount of electricity generated by a power generation facility, and the unit price of the energy utility is a cost related to the unit price of electricity purchase.

12. The energy operation support system of claim 8, further comprising a response characteristics calculation unit that calculates an equipment upper limit taking into account the response characteristics of the energy utility during a transition period from shutdown to operation or from operation to shutdown based on a shutdown plan for the equipment, and the upper limit alleviation unit sets the operational upper limit using the equipment upper limit taking into account the response characteristics.

13. The energy operation support system of claim 8, further comprising a tuning screen display unit that sets and displays the predetermined ratio of the operational upper limit to the equipment upper limit and a weighting coefficient of the cost related to the adjustment variable.

14. An energy operation device that controls equipment in a steelworks in accordance with the operating conditions of energy utilities output from the output section of the energy operation support device described in claim 7.

15. An energy operation device that controls equipment within a steelworks in accordance with the energy utility operation conditions output from the output section of the energy operation support system described in claim 8.

16. A display terminal device constituting an energy operation support system in a steelworks, comprising: an information acquisition unit that acquires information including the operating conditions of optimized energy utilities in equipment within the steelworks; and an information display unit that displays the information, wherein the information includes the operating conditions of optimized energy utilities in the equipment calculated by an optimization calculation that minimizes an objective function including the cost related to adjustment variables of energy utilities that relax an operational upper limit set for an equipment upper limit on the output of the energy equipment of the steelworks, and the total energy operation cost of the steelworks.

17. The display terminal device according to claim 16, further comprising a tuning screen display unit which sets and displays a predetermined ratio of the operational upper limit to the equipment upper limit used in the optimization calculation and a weighting coefficient of the cost related to the adjustment variable relative to the total energy operation cost of the steelworks, and the information display unit displays the information calculated by the optimization calculation using the predetermined ratio and the weighting coefficient which are set and displayed on the tuning screen display unit.

18. An energy operation support method in a steelworks, comprising: an optimization step in which an energy operation support device in a steelworks optimizes the operation of energy utilities in equipment in the steelworks; and an operation upper limit setting step in which an operation upper limit is set to an equipment upper limit, which is an upper limit on the output of the equipment capacity of the equipment, wherein the operation upper limit setting step sets the operation upper limit at a target time or target calculation period by determining a predetermined ratio to the equipment upper limit, and the optimization calculation in the optimization step includes, as objective functions, a total energy operation cost of the steelworks and an adjustment variable for energy utilities with an upper limit equal to the difference between the equipment upper limit and the operation upper limit.

19. The energy operation support method described in claim 18, further comprising: a response characteristics calculation step in which the energy operation support device calculates an equipment upper limit taking into account the response characteristics of the energy utility during a transition period from shutdown to operation or from operation to shutdown based on a shutdown plan for the equipment; and the operation upper limit setting step sets the operation upper limit using the equipment upper limit taking into account the response characteristics.

20. A method for operating a steelworks, comprising a step of operating the steelworks in accordance with decision variables calculated by the optimization calculation of the energy operation support method according to claim 19.

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