METHOD FOR CONTROLLING PREHEATING TEMPERATURE OF MATERIAL TO BE REDUCED IN REDUCTION FURNACE

摘要

PURPOSE:To control the preheating temp. of a material to be reduced so as to coincide with a target preheating temp. with high accuracy by dividing the discharge gas passages of a heat exchanger crossing the passage for the material to be reduced to plural blocks and controlling the temps. and flow rates of the exhaust gases to the respective blocks. CONSTITUTION:Iron powder 1 which is the material to be reduced and is supplied to a reduction furnace (not shown in figure) is allowed to flow down in the iron powder passage 9 of a heat exchanger 24 and the waste combustion gas is passed in the exhaust gas passage 10 crossing the passage 9 by which the inside of the passage is heated. The passage 10 is divided to the plural blocks 10a-10c and iron powder temp. detectors T1-T18 and exhaust gas temp. detectors Tg1-Tg3 are disposed in accordance with the respective blocks. The detected temps. therefrom and the target preheating temp. Ts of the iron powder from a setter 16 are inputted to a microcomputer 14 which computes the optimum heat patterns and the target iron powder temp. for each of the respective blocks 10a-10c. External air introducing dampers 6a-6c and exhaust gas flow rate control dampers 11a-11c are controlled via a control unit 15 in order to obtain the required temps. and flow rates of the exhaust gas based thereon.