The Process of Low Coke Rate Operation Under All Pellets at Kobe Blast Furnace

摘要

Kobe Works, not having any coke plants, purchases coke from the outside, and its unit price of coke is higher than that of other steel works. Therefore, at Kobe Works we have attempted to achieve a low coke rate operation for the blast furnace. Furthermore, the sintering process was closed in 1999 to allow for the construction of a power plant as a profit-improving measure, and transferred to all-pellet operation (pellet ratio: 73%, lump ore: 27%) in 2000 [e.g.,1]. Self-fluxed dolomite pellets produced at the pellet plant of our Kakogawa Works are transported by ship and used by Kobe Works. Kobe Works, as the only site in Japan that has adopted and continued all-pellet operation, aims at optimum complex control [e.g.,2] of burden distribution with high pellet composition, and of pulverized coal combustion with multiple coal types in the 4th campaign (from 2007). At the same time, by replacing lump ore by self-fluxed dolomite pellets [e.g.,3], Kobe Works improved the meltdown property of ore at high temperature. As a result, under severe conditions of high pellet ratio (80%) and all raw materials already stored in our yard, Kobe Woks achieved a low coke rate operation of 283 kg/t.