PURPOSE: To effectively utilize generated exhaust gas as energy source by parallelly arranging one pair of converter type smelting reduction furnace, supplying the exhaust gas from the furnace having a high secondary combustion ratio into a pre-treating furnace and using the exhaust gas from the furnace having a low secondary combustion ratio as fuel gas.
CONSTITUTION: The smelting reduction furnaces 1, 2 are parallelly arranged, and bottom blowing and top blowing are executed while supplying the pre- treated ore and carbonaceous material from the pre-treating furnace 4 (rotary kiln) and the smelting reduction of ore is executed by supplying the carbonaceous material and flux. Then the secondary combustion ratio in the smelting reduction furnace 2 shown in the equation is made to 5-35%, and this exhaust gas is sucked under an unburnt condition, and after removing dust, the gas is stored in a gas holder 3, and as necessary, used as the fuel gas. On the other hand, the secondary combustion ratio in the smelting reduction furnace 1 is made to 40-68% and this exhaust gas is supplied to the pre-treating furnace 4 under high temp. condition and is perfectly burnt. By this method, the unit consumption of coal and oxygen gas are reduced, and also the suitable quantity of fuel gas is obtd. as byproduct.
MATSUO MITSUTAKA
SAITO TSUTOMU
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