VERTICAL FURNACE AND METHOD OF OPERATING THE SAME

摘要

A shaft furnace for producing pig iron by charging an iron source of high metallization rate whose average metallization rate is 95% or greater and a solid fuel containing 70 to 100 mass% of blast furnace coke in layered state or mixed state from the furnace top onto a bed of coke filling a lower region of the furnace and melting the iron source by blowing in air through tuyeres at the bottom region of the furnace, which shaft furnace is characterized that: (i) the distance from the lower face of the lowest tier of tuyeres in the direction of the furnace height to the upper face of a bottom plate at the furnace bottom is 0.7-fold or greater the furnace diameter at the location of the lower face of the tuyeres; and (ii) as calculated from the heat conductivities and thicknesses of lining refractories individually installed on the shaft part, tuyere periphery, wall portion on the furnace bottom side and the bottom plate at the furnace bottom, the furnace body heat radiation per unit internal volume in the furnace height range from the shaft part to the bottom plate at the furnace bottom is 0.15 MW/m 3 or less.