JPS57143406A - Control method for blast quantity during reduction of stock line and blowing out of blast furnace - Google Patents

Abstract

PURPOSE:To control the blast quantity in the operation for reduction of the stock line by using the fluidization chart and pressure drop chart which are determined beforehand, and setting the blast quantity of the next stage successively on the basis of the specific position of the reduced stock line in the stage of reduction of the stock line and blowing out of a blast furnace. CONSTITUTION:In the operation of a blast furnace, a fluidization chart and a pressure drop chart are determined from the calculated values relating to the average pressure distributions in the furnace. During the operation for reduction of the stock line, the actually measured furnace top pressure, raceway pressure and blast quantity are measured, and from the pressure drop chart, the air permeability Bo of the charging material is determined, and from the fluidization chart, an average fluidization index FIB is determined. These are compared with the target values, and the rate of danger for blow-by is decided. Next, the furnace top pressure is given, and from the fluidization chart, the square difference of the target pressure with respect to the target FIB is determined, and from the pressure drop chart, the target blast quantity corresponding to the square difference of the target pressure at a constant level is read. These are set as the blast quantity of the next stage. Thereby, the control for blast quantity which does not cause slip and blow-by in the operation for reduction of the stock line is accomplished.