Blast Furnace Granulated Coal Injection

摘要

Production levels on each furnace exceeded 7000 NTHM/day during July. The211u001ecombined production of 14,326 was a result of lower coke rates and below average 211u001edelay rates on both furnaces, The combined production was at its highest level 211u001esince September 1997. In August, the combined productivity declined to less than 211u001e13,500 NTHM/day. Although D furnace maintained a production rate in excess of 211u001e7000 NTHM/day, C furnace was lower because of a castfloor breakout and subsequent 211u001efive day repair from August 26-30. Despite the lower productivity in August, 211u001einjected coal and furnace coke rates were very good during the month. During 211u001eSeptember, the operation was difficult as a result of higher delays on both 211u001efurnaces. The combined average monthly delay rate was considerably above the 211u001etwenty-month average of 113 minutes per day and the combined average monthly 211u001eproduction was less than 14,000 NTHM/day. Higher furnace coke rates at lower coal 211u001einjection levels also contributed to the decrease. Additionally, the coke rate on 211u001eboth furnaces was increased substantially and the injected coal rate was 211u001edecreased in preparation for the high volatile Colorado coal trial that started 211u001eon September 28. The furnace process results for this quarter are shown in Tables 211u001e1A and 1B. In addition, the last twelve months of injected coal and coke rates 211u001efor each furnace are shown in Figures 1 and 2.