Use of a logical-statistical model to optimize the charging parameters of a blast furnace

Abstract

The process of the reduction of vanadium in a blast furnace is determined to a significant extent by the structure of the stock, the charging regime (including the cyclicity of the charging operation), the charging sequence, stockline level, the burden ratio, and the operating regime of the revolving distributor. The profile of the charge materials and the position and height of the ore ridge in the top of the furnace are important parameters, since they determine the nonuniformity of the distribution of the gas flow and, thus, the use of the reducing potential of the gas [1][2][3].In constructing the logical-statistical balance model in [4], an attempt was made to account for the nonuniformity of the gas-flow distribution as part of the analysis of the smelting process. The nonuniformity coefficient ~t was introduced. The coefficient is equal to unity for an ideal distribution, while deviations are recorded in fractions such as 0.95. Here, some of the gas (in the given example, 0.05) is released from the furnace, by-passing the ore-bearing materials.If the nonuniformity of the gas distribution across the furnace is linked with a heat-transfer and mass-transfer characteristic of the operation of the furnace -the ratio m of the water equivalents of the charge and the gas -then the range of theoretical and practical problems that can be solved [5, 6] where n a is the number of the section in which the value of a is greatest.It follows from Eq. (1) that the gas distribution across the furnace may be ideal when a = m. Using (1) with known/.t, m, and n, we can determine a. We can then use Eq. (2) to find d and, after performing calculations with the two-dimensional model, we can analyze the work done by the gas along and across the furnace.To determine the validity of the proposed model, we studied the operation of a 1033-m 3 furnace at the Chusovoi Metallurgical Plant. During the study period (August 18-22, 1998), the iron-ore-based part of the charge consisted of 60% Kachkanar pellets, 30% imported sinter, and 10% local sinter. The productivity of the furnace was 1620 tons/day; coke rate was 546 kg/ton; the furnace was operated on an air blast heated to 892~ the consumption of natural gas was 31 m 3.Chusovoi Metallurgical Plant and the Institute of Metallurgy (in the Ural Division of the Russian Academy of Sciences).