Optimal calculation method of energy operating condition in iron mill, optimal calculation device of energy operating condition in iron mill, and running method of iron mill

An operating method of an iron mill using an optimal calculation method of an energy operating condition in the iron mill, the optimal calculation method being executed by an information processing apparatus configured to perform a periodic optimization process for an energy management system of the iron mill, the operating method comprising:

• defining time points, starting at a current time, within a predetermined period of time based on a predetermined cycle;
• defining a total energy operation cost of the iron mill within the predetermined period of time as an evaluation function,
• calculating an operation condition of an energy facility in the iron mill as a decision variable based on actual values and estimated values of a generation amount and a used amount of energy utility for each of factories comprised in the iron mill, wherein the decision variable is calculated such that the evaluation function decreases over the predetermined period of time, and
• controlling the operation of the power generation facility in the iron mill based on the calculated decision variable, wherein
• the energy utility for each of the factories includes gas, steam, and electric power,
• the energy facility includes a mixed gas production facility, a gas holder, a coke drying quenching facility, a top-pressure recovery turbine facility, and a power generation facility that uses by-product gas, heavy oil, or steam extraction,
• the operation condition includes an amount of the by-product gas, the heavy oil or the steam extraction used in each power generation facility, or a storage amount or a discharge amount of the gas holder,
• a designated time in the predetermined period is defined, and a series of time points after the designated time within the predetermined period are set to an aggregation period,
• the calculating includes:
• calculating the decision variable related to the power generation facility included in the energy facility at each of the time points from the current time to the designated time in the predetermined period, and
• within the aggregation period, calculating the decision variable by imposing an equality constraint such that the decision variable related to the power generation facility included in the energy facility is constant within the aggregation period.