BLAST FURNACE OPERATION METHOD

摘要

A lance 4 for injecting a fuel through a tuyere 3 is a double tube. Pulverized coal is injected through an inner tube 21 of the double wall lance 4. Oxygen is injected through an outer tube 22 of the double wall lance 4. Notches 23 are formed in a injecting front end of the inner tube 21 of the double wall lance 4. The concentration of oxygen in a gas composed of a carrier gas for the pulverized coal and a gas injected through the outer tube is 35% by volume or more. Even in an operation using pulverized coal having a volatile matter content of 25 mass% or less at a high pulverized coal ratio of 150 kg/t or more, the combustion temperature can be increased, and consequently CO 2 emissions can be reduced. The specific oxygen consumption can be suppressed by decreasing the oxygen concentration to less than 70% by volume. The notches 23 may be circumferentially evenly spaced in the inner tube 21 of the double wall lance 4 and further improve combustion efficiency.