(STSI-27)Implementation and on-line useof a dynamic process modelat the ArcelorMittal-DofascoElectric Arc Furnace

摘要

Electric arc furnace (EAF) tap temperature control isa key step in EAF process optimization;;it impacts onenergy consumption (kWh/t), productivity (power-ontime) and costs. The temperature control is achallenge because of the complexity of EAFoperation, such as varying scrap conditions. In mostEAF shops, the process control is mainly dependedon operator experience with a common practice ofover-heating (tapping steel at higher temperaturethan required). In order to better control tappingtemperatures and the overall process, a dynamicphysical model was developed by CRM –ArcelorMittal (AM) Global R&D, as a common project.This model simulates the complete steelmakingprocess in an EAF. The model, when used on-line, isfed continuously (typ. in 6 sec time steps) with alldynamic input variables of the furnace (electricalpower, burner natural gas and oxygen, lance oxygen,fine carbon injection, etc.), together with informationon scrap and hot-metal charging, as well as fluxesand other additions. It calculates the evolution(volume, weight, chemistry and temperature) ofscrap, skull, liquid steel and slag as functions of timeduring the progress of the heat. The key calculatedresults - liquid steel temperature and carbon content -together with some other important information, arecontinuously displayed to the operator, in a newlydeveloped user interface. This information guides theoperator to better detect and control the end-point ofthe heat (temperature and carbon content).In 2009, this EAF model was adapted toArcelorMittal-Dofasco electric steelmaking for taptemperature control. After several ?fine tuning? steps,the model was implemented on-line, early 2010, andquickly accepted by furnace operators.Within the first half of 2010 the average tappingtemperature was decreased by approximately 10°C.The implementation of an accurate data validationmodule and a fine tuning to Dofasco?s scrap and hotmetalcharging practice, mid 2010, helps to furtherimprove the process performance and reduceoperating costs.