HEAT EXCHANGING METHOD IN SMELTING REDUCTION IRON-MAKING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce heat load to equipment and to save the energy in a smelting reduction process by using gaseous nitrogen used to cooling of the smelting reduction equipment to the adjustment of moisture in a raw material. SOLUTION: High temp. gas produced from a smelting reduction furnace 1 is introduced into a hot cyclone 5 to remove dust in the produced gas. The produced gas removing the dust is introduced into a pre-reduction furnace 2. In a cooling device 7, the gaseous nitrogen is used as cooling gas. The used cooling gas is fed to a raw material drying device and used to the gas for drying the raw material. The cooling gas uses the gaseous nitrogen by-produced at the time of producing gaseous oxygen or a mixed gas of this gaseous nitrogen and the gas produced in the smelting reduction equipment. The temp. of the cooling gas at the outlet of the cooling device 7 is desirably adjusted to 150-550 deg.C. Further, the temp. of the produced gas introduced into the pre- reduction furnace 2 is desirably <1000 deg.C. The temp. of the cooling gas introduced into the raw material drying device 6 is desirably in the range of 100-350 deg.C.