Research On Ladle Scheduling Based On UML And Plant Simulation In Steel Plant

In the production process of steelmaking&continuous casting, ladle is the carrierof liquid steel in the metallurgical processing with different equipments. From therefining furnaces, molten steel is transferred via ladles,containing one heat of steel, to aladle metallurgical facility(LMF), then molten steel from the LMF where undergo anyof several refining processes moves to the casting step and takes solid form. After theladles of molten steel are drained into tundish, the empty ladle move to slag pour-outequipment and then the ladle tilting platform, and in the end it reach the BOF onceagain. Ladle scheduling have a direct effect upon the scheduling of the entiresteelmaking process. And reasonable optimizing of ladle Scheduling is significant tobalance the load of working procedure, tightly link up the material flow, highly improveproduction efficiency and quality of products, decrease the consumption of energysources and material.In the process of ladle transportation, there are many ladle routes and involvedquite a few working procedure and equipments, besides it is faced with manydisturbances. So the ladle scheduling is very complex, which has some limitations, suchas multi-objective, multi-constrains and uncertainty. In most steel mills, the cis-tappingprogram only includes BOF tapping end time and CC converter beginning time, butdon’t include similar processing program on the auxiliary equipments involved in theprocess of steelmaking. So, this paper will be focused on the ladle and establish aproduction scheduling optimization mathematical model. It also presents a solution forthis model, which based on genetic algorithm and simulation model, then applies UMLto analyze and design the simulation scheduling system, and then using PlantSimulation platform to achieve the design objective. In the last, the author gets aexcellent ladle scheduling program. Reasonable and orderly ladle scheduling will notonly improve the steelmaking production rhythm but also balance the equipment load,improve production efficiency and reduce production costs.The main work and contents are as follows:(1) Ladle running paths analysis. Considering the ladle scheduling system inthe production model of steelmaking&continuous casting, we analysis and summarizesthe turn around process of ladle transportation.(2) With the regard of real steelmaking production and ladle scheduling problems, an optimal model is established for the purpose of minimal waiting time andthe minimal number of ladles online. Furthermore under the analysis of the mathematicmodel, the author designs an encoding method of gene by ladle path and chromosomeby the ladle paths when the heats are all delivery to the CC. The fitness function iscomprised of weighted sum of minimum waiting time and the ladle numbers. By manytimes of simulation and optimization, we can get a excellent scheduling plan.(3) In this paper, the author applies UML to analyze and design the simulationsystem, and then set up the hierarchical and modularized program by the software ofPlant Simulation. Considering the ladle scheduling system in one domestic steel plant,the author builds up the simulation models of regular production and abnormalproduction. Simulation result show that the waiting time that ladle wait at theequipments is greatly reduced, and the time of full ladle turning over reduces muchmore, the number of ladles online is well in agreement with the reality of themanufacture. Above all, the simulation results are given to demonstrate that themodeling method is effective.Through applying UML and Plant Simulation in the simulation field, this paperprovided a new general thought for the relative research of the complicated steelmakingproduction and scheduling，which is modeled with the unified modeling language andthen simulated by the software of Plant Simulation and optimized the simulation resultswith the improved genetic algorithm. With a steel works as an example, the simulationresults show that this method is very effective and generic and can be used for othersituation. And it will provide great support and help for the enterprise resourceallocation and planning and scheduling problems.