REFINING CONTROL OF TOP- AND BOTTOM-BLOWING CONVERTER BY MANIPULATING BOTTOM-BLOWN GAS FLOW RATE.

Abstract

The effect of gas bottom-blowing condition on the refining characteristics of a top- and bottom-blowing converter in comparison with top-blowing condition has been studied on the basis of the amount of accumulated oxygen in the converter (Os) which represents the change in oxidation-reduction reactions between hot metal and slag. Dynamic control of blowing reaction in the top- and bottom-blowing converter has been achieved with the flow rate of bottom-blown gas as a manipulated variable and the variation of Os as a controlled variable. By application of the multistep optimum control theory to the blowing reaction model, the stability of blowing operation and metallurgical characteristics, i. e. , the range of changes in (T. Fe) of slag, phosphorus and manganese concentration of molten steel at blow end, was narrowed. 16 Refs.