Maximum rates of pulverized coal injection in ironmaking blast furnaces

Abstract

A theoretical study is made on the maximum injection rates of pulverized coal in ironmaking blast furnaces.The study takes account of two restrictive conditions which enable stable blast furnace operations to be maintained. One is to burn out the injected coal in the raceway zone and the other is to avoid the coal ash deposition on the blowpipe wall. The predicted maximum injection rates for some operating blast furnaces are about 190-210 kg per ton of pig-iron produced, which seem to be reasonable in comparison with experiences reported. Also, the influences of pulverized coal injection on the coke consumption, the production rate of pig-iron and the bosh gas temperature are examined in relation to some blast gas conditions such as the oxygen enrichment and the moisture addition. © 2011 ISIJ.