| High titanium pattern vanadic titanomagnetite is smelted in normal blast furnaces(BF) at Pan Steel. BF operation is naturally distinct from those smelted with ordinary ores. The coke of Pan Steel is of enough cool strength, however, inadequate thermal properties. In order to meet BF operation with high pulverized coal injection(PCI) ratio, the solution loss behavior of coke in BF has been investigated. Being directed at performance varying of tuyere coke, various influential factors and their effects have been analyzed, which include size composition, slag and iron coherent condition, pore structure and optical texture, the quantity varying of unburnt pulverized coal(UPC) particles below 0.5mm of tuyere coke. The length of the raceway is measured. The appropriate length of the raceway is theoretically derived, and the limitation of PCI ratio as well. The findings provide valuable theoretical basis for improving coke quality and stabilizing BF operation at Pan Steel.For №1 BF of Pan Steel at present operation conditions, investigation indicates that the length of the raceway is about 2m. With the increase of PCI ratio, the length of the raceway shortened, and the quantity of tuyere coke below 6mm increased, also slag and iron coherent rate in tuyere coke, however, the theoretical combustion temperature decreased. Reducing tuyere diameter is beneficial to the activation of hearth. But the loss of coke in crucible will increase and the circular flow of molten iron will be enhanced also, which is harmful to the longevity of crucible.Under current operation conditions, the limit of PCI ratio of №1 BF at Pan Steel is 209.4kg/t.p presupposed the amount of UPC in slag be not more than 9% of total powder coal injected. Injecting coal blend is beneficial to promote the utilization of coal powder. The pore structure and optical texture of tuyere coke indicate that the coke quality is improved with the addition of certain proportion of lowly ranked coal into the coking coal blend. |
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