Study On Optimical Method Of Steelmaking-Continuous Casting Production Planning Involved In Ladle Turn-around

In the production process of steelmaking-continuous casting, ladle turnover includes full ladle transportation and empty ladle transportation. At present, the research on the production planning of steelmaking-continuous casting just considers the full ladle transportation, however, in the production process, the empty ladle transportation can affect the full ladle transportation directly. Many steel plants frequently have to wait the ladle during the converter tapping, which has a direct impact on the production efficiency. As to this problem, empty ladle transportation can be included in the planning process , by establishing the production process model including empty ladle transportation, production planning is made to ensure the empty ladle can arrive tapping position on time.Production process of steelmaking-continuous casting is very complex, the key to establish optimal job planning model is to make a detailed analysis on the production process and modeling. As to the network characteristics and dynamic characteristics of steelmaking-continuous casting production process, the dynamic network method is proposed to analyze and model the production process. Based on using the dynamic network method to analyze production process and model, the optimal model for steelmaking-continuous casting production planning is established, the minimal waiting time and the minimal number of ladles are the targets, sequence casting, starting pouring as soon as possible, using the ladle online timely, no conflicts among equipments are the constraints, and the machining path is the decision variable. Simulation and genetic algorithm are combined to solve the optimal model. Reverse process simulation model is embedded in to the evolution process of genetic algorithm to optimize the processing paths, the processing paths of each furnace are the chromosomes, the minimum waiting time is the fitness, by many times simulation optimization ,the more optimal production planning is obtained.(including the full and empty ladle transportation). The dynamic network simulation model is established by using the modeling tool EM-plant, and the genetic algorithm is implemented by combining the simtalk simulation language and the inner genetic algorithm.Research showed that:①the proposed dynamic network method is suitable for the production process analysis and modeling of steelmaking-continuous casting;②the method that reverse process simulation and genetic algorithm are combined to solve optimal model, simplified the optimal model and its solution algorithm, and can make out the production plan which has no conflicts among equipments, the plan can assure the sequence casting and starting pouring as soon as possible, at the same time, the plan's waiting time can be accepted.③considering the empty ladle transportation during making the production plan can optimize the empty transportation process to ensure the empty ladle arrive the tapping position on time.Using the Panzhihua steel plant as an example, base on analyzing the production process, the production process model including the empty ladle transportation is established. Inputting 19 casting times and121heats in one day, the production planning including empty ladle transportation is made out and optimized. The results shows:①the system can make out the production plan in a short time which can ensure sequence casting and the pouring time, the average waiting time of each furnace before each working operation is less than 1 min.②during the production planning, compared to production results, the time of full ladle transportation reduces more than 10 min generally, and time fluctuation is small;③the empty ladle transportation time is very stable, compared to empirical values, the time reduces more than 3min;④the number of ladles is 21, in the empirical range 19-24;⑤the whole empty ladle can arrive the tapping position on time.So the research work achieves obvious progress, the proposed optimal method for production planning of steelmaking-continuous casting involved in the ladle turn-around provides a new thought for the relative research of the complicated steelmaking production, and the application of the research result provides a new method to optimize steelmaking production process, improve the enforceability of production planning, promoting the scheduling level of the steelmaking production.