(EECR-41)Dynamic prediction of melt temperature for optimised energy input and temperature control in steelmaking

摘要

Within steelmaking an important control parameter withrelevance for energy consumption is the adjustment ofthe target casting temperature of liquid steel. An optimizedtemperature control is particularly important forsteelmaking plants in which the entire energy buffer tocompensate losses during secondary metallurgy ladletreatment has to be adjusted before tapping of theprimary steelmaking plant or during a consecutive ladlefurnace treatment. To be on the safe side, this energybuffer is often over-dimensioned, so that afterwards acooling scrap addition or extensive bottom or lancestirring is required to lower the melt temperature. Incontrast, a heat becoming too cold for the casting processhas to be reheated at the ladle furnace or evenrecharged at the primary steelmaking facility, which isconnected with a large additional energy input.To avoid an unnecessarily high energy input in the BOFor the LF, which then has to be lowered during ladletreatment, a system for through process prediction oftemperature evolution within the complete steelmakingroute has been developed. It covers the primary steelmakingprocess from BOF resp. EAF tapping via ladletreatment in different secondary metallurgy plants up tothe delivery of the heat to the caster. The effect of thethermal status of the tapping ladle on the evolution ofthe steel temperature loss rate is considered within thedynamic model calculations.On the basis of the dynamic through process temperatureprediction, which is performed for the entire treatmentalready before BOF or EAF tapping, the adjustmentof the BOF tapping temperature resp. the electricalenergy input in the LF is optimised, so that furthertemperature control actions like cooling scrap addition,intensive stirring or chemical heating are minimised.The system for through process temperature control isapplied at the oxygen steelmaking plant of HuttenwerkeKrupp Mannesmann (HKM) in Duisburg, Germany, andthe electric steelmaking plant of Peiner Trager GmbHin Peine, Germany. The average BOF tapping temperatureat HKM was decreased by 10 K, leading to energysavings of about 5 kWh / ton of liquid steel. At PTG theelectrical energy input at the ladle furnace was decreasedby about 2.4 kWh / ton of liquid steel.