Operational results for high pulverized coal injection rate at Kimitsu No. 3 blast furnace

Abstract

In order to further develop the technology for high-rate pulverized coal injection (PCI), namely over 200 kg/t-pig, Nippon Steel performed a high injection rate test at the Kimitsu No. 3 blast furnace in November, 1993. The paper describes PCI equipment; the operational design of the test, including blast conditions, reducibility of sinter, coke strength and burden distribution; and test results. These results include a discussion of the transition of operation, burden distribution control, replacement ratio of coke, permeability at upper and lower parts of the furnace, reducibility at lower part of the furnace, accumulation of fines in the deadman, and generation and accumulation of unburnt char. Stable operation was achieved at a PCI rate of 190 kg/t-pig. With injection rates between 200--300 kg/t-pig, the problem becomes how to improve the reduction-meltdown behavior in the lower part of the furnace.