| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for operating a blast furnace, which achieves a further elevation in combustion temperature and reduction in specific consumption of a reducing material. <P>SOLUTION: When using two or more lances for blowing reducing materials from tuyeres, while using a pulverized coal serving as a solid reducing material and an LNG serving as a flammable reducing agent, the lances are positioned such that an axis line extending from the front end of a lance for blowing the LNG intersects with an axis line extending from the front end of a lance for blowing the pulverized coal. Consequently, the main streams of the LNG and the pulverized coal blown in from the different lances overlap, and the LNG burns first and explosively expands upon coming into contact with O<SB POS="POST">2</SB>, and the temperature of the pulverized coal is significantly elevated. This significantly elevates combustion temperature, thereby reducing the specific consumption of the reducing materials. Further, when a double-pipe lance is used as a lance for blowing pulverized coal, the pulverized coal is blown in through an inner pipe, and oxygen is blown in through an outer pipe, thereby ensuring enough oxygen required for burning the pulverized coal and further improving the combustibility. Furthermore, the flow velocity at the outlet of the lance is set to 20-120 m/sec to prevent the deformation of the lance. <P>COPYRIGHT: (C)2013,JPO&INPIT |
