| 摘要 |
PURPOSE:To stabilize the furnace condition over a long period of time by holding a fixed number of adjoining tuyere groups closed while the production is being reduced and moving these closed tuyere groups in their circumferential direction before inert zones are formed. CONSTITUTION:While the production with the blast furnace is under cutback, a fixed number of tuyeres adjoining to the tuyeres disposed in the circumferential direction in the furnace, e.g., Nos. 1-5 are held fully closed and the remaining ones are held open. Inert zones are forecast with the thermometers provided to the furnace body and before the inert zones by the closed tuyerse are formed, the closed tuyeres are moved two pieces each sequentially in the circumferential direction, thus air is blasted by closing the Nos. 6, 7 tuyeres and changing over the Nos. 1,2 tuyeres in the rear part of the moving direction to open tuyeres. In this way, the closed tuyere groups are moved at the specified date-number pitch in the clockwise rotating direction. Here, the number of the tuyeres to be selectively opened and closed out of the closed tuyeres is desirably 30-40% of the closed tuyere groups. By this method, the blast furnace is operated in a stable state and the frequencies of tuyere breakages are suppressed. |
