| 摘要 |
PROBLEM TO BE SOLVED: To provide a blast furnace operation method that enables an improvement in combustion rate of powdered coal blown from a tuyere and a reduction in specific consumption of a reducing material.SOLUTION: When simultaneously blowing powdered coal as a solid reducing material, LNG as a gaseous reducing material, and oxygen as a combustion-supporting gas from a lance 4 into a tuyere 3, by using the lance 4 in which a first pipe 21 for blowing powdered coal and a second pipe 22 for blowing oxygen are positioned in parallel and the two blowing pipes 21 and 22 are included within a third pipe 23 for blowing LNG, a large opening between the blowing pipes can be maintained without extremely increasing the outer diameter of the lance 4 and thereby both the securement of cooling capacity and the improvement in combustibility can be attained and the specific consumption of a reducing material can be reduced. Also, relative to the first pipe 21 for blowing powdered coal, by having the second pipe 22 for blowing oxygen and/or LNG flow positioned in the lower side of gas flow direction within the gas flow pipe, the mixing between oxygen and powdered coal is promoted as well as the powdered coal is heated up by the burning field of oxygen and LNG, and the combustibility is improved. |
