Observation and control of AOD process with exhaust gas measurement

摘要

An AOD converter for stainless steel production at the Bochum steel plant of Krupp Thyssen Nirosta has been equipped with measurement devices for the exhaust gas flow rate and CO, CO_2, O_2 concentrations. By means of carbon and oxygen balances, the rates of decarburisation and metal oxidation as well as weight and composition of steel and slag are continuously calculated. The accuracy of the balanced carbon content can be improved by using the characteristic dependence of the decarburisation rate on the carbon content during the final decarburisation period. With dynamic blowing control according to the decreasing oxygen demand for decarburisation during this period, metal oxidation can be minimised and the decarburisation rate can be kept as high as possible under given thermodynamic restrictions.