Dynamic Controlling Model Of Converter Based On Analysis Of Fume Components

The mathematical control model for converter steelmaking is established on the baseof the thermodynamics and dynamics analysis of the oxidation process duringsteelmaking, which can be used for the construction of the dynamic control system ofonline sampling, control and end-point prediction. The off-line operation results showedthat this mode stands out for its high double hitting ratio at the end-point and providesgood direction effect on the converter production.Based on the characteristic of BOF steelmaking process, the prediction mode of theend-point carbon content, temperature and oxygen content in steel is set up throughseveral stages which builded with different mathematical model, which providefoundation to improve the prediction hitting rate for steelmaking process and end-point.The dynamic early warning system of the slag station has been established bycalculating the oxygen accumulation amount and the utilization ratio of oxygen duringdecarburization with the combination of the oxygen lance weighing model. By givingalarms in advance for unusual conditions of slag station, a stable smelting process isensured.The dynamic prediction model of the content of manganese, silicon and phosphorusin the molten steel is set up on base of the analysis of the converter gas and the partitionratio of oxygen between steel and slag. Considering the effect of the CaO content in theslag on the dephosphorization rate at earlier stage of the melting, the dynamic predictionmodel of the phosphorus content takes the melting rate of lime into account during theearly melting stage.The computational results of the off-line batching system showed that the ratio ofprediction deviation of the oxygen supply lower than300Nm3, the ammount of limeadditon lower than300kg, the amount of dolomite addition lower than300kg and theamount of ore addtion lower than300kg is84.8%,78.3%,87.0%and78.3%, respectively,which which can be used for guiding the actual production.Through the off-line running of the prediciton model, it showed that the predictiondeviation of the temperature of the molten steel lower than20℃and the carbon contentin the molten steel lower than0.02%is84.8%and84.8%, respectively. Taking thecarbon content lower than0.02%and the temperature lower than20℃into accountsimultaneously, the prediction hiting ratio is73.9%.