TEST ON HIGH-RATE PULVERIZED COAL INJECTION OPERATION AT KIMITSU NO-3BLAST-FURNACE

With reference to results of off-line model experiments and actual fur nace operation tests performed beforehand, a high-rate pulverized coal injection operation test was carried out at Kimitsu No. 3 blast furna ce and the following conclusions have been derived: (1) A stable opera tion has been achieved at the pulverized coal rate of 190 kg/t-pig by the control of heat flow ratio and the burden distribution control of peripheral gas flow suppression, with the production of low Al2O3, hig h-reducible sinter and the raise of cold and hot strengths of coke. (2 ) With an operation performed at the pulverized coal rate over 200 kg/ t-pig and the coke rate below 300 kg/t-pig, it has become clear that a technical subject posed at this operation is how to improve the reduc tion-meltdown behavior in the lower pare of furnace. (3) It has become clear that a factor controlling the pulverized coal injection at the actual furnace is the discharge of unburnt char from the furnace top. Setting the upper limit of injection rate certainly is a subject to be worked out hereafter.