| 摘要 |
Provided is a method for operating a blast furnace with which the combustion efficiency of a solid fuel such as powdered coal is improved, thereby making it possible to improve productivity and reduce CO2 emissions. Powdered coal and oxygen are blown in from an upstream lance 4 configured from a double tube, and LNG is blown in from a downstream lance 6 located downstream from the upstream lance 4 in the direction of the hot air blast, whereby supplemental oxygen for use in combustion of the LNG is provided from the upstream lance 4, and the powdered coal heated by the combustion of the LNG is combusted together with the supplied oxygen or with oxygen in the air blast. The direction in which the LNG is blown from the downstream lance 6 with respect to the blast direction ranges from -30° to 45°, and the position at which the LNG is blown in from the downstream lance 6 with reference to the position at which the upstream lance 4 is inserted into a blast tube 2 ranges from 160° to 200° expressed in terms of angle in the blast-tube circumferential direction, where a direction perpendicular to the hot air blast direction is designated as 0°, the downstream direction therefrom in the direction of the hot air blast is designated as positive, and the upstream direction is designated as negative. |
