Selection of the Bell-Less Top Mode of Operation Based on the Data on the Gas Distribution in the Furnace Top and the Shape of the Melting Zone in the Lower Part of the Blast Furnace

Abstract

The collected data on the influence of the parameters of the melting zone on the operation of a blast furnace (BF) give a new look on the formation of guidelines for the choice of the operating mode a bell-less top (BLT) charging system aimed at improving the efficiency of operation of the blast furnace and its lifetime. The management of the “no-feedback” bell-less top operation mode without application of the criteria of BF operation often results in the inefficient usage of its advantages, which sometimes leads to a decrease in the productivity of the BF. The operating control over the BLT charging system aimed at the improvement of the efficiency of BF should be realized with feedback with regard for the changes in the following operating criteria of the BF: optimization of the radial gas distribution in the BF top; minimization of the circumferential gas distribution in the BF top; optimization of the thermal state of the furnace; optimization of the shape and location of the melting zone in the boshes of the BF; monitoring and control of the temperature of materials and smelting products operating in contact with the furnace lining in the boshes, flare, and the bottom part of the furnace shaft. The strategic control over the BLT operation should be performed with realization of the target function, i.e., with an aim to increase the lifetime of the BF by using the following criteria of its operation: the minimization of the FeO content in the primary slag and the optimization of the temperature of materials and smelting products adjacent to the furnace lining in the boshes, in the flare, and in the bottom part of the furnace shaft.