In order to evaluate the effect of powder on the blast furnace operation, the 2-dimensional behavior of gas and powder in packed bed with a tuyere on it's wall side were studied by a mathematical simulation model as well as a cold model experiment. Results obtained are as follows;
1) When the gas velocity along the wall side is decreased, powder tends to accumulate near the wall above tuyere resulting in the increase in pressure drop of gas and the decrease in gas flow rate near the wall.
2) The deterioration of gas permeability accompanied by the decrease in wall temperature at the lower part during the reduced production operation of blast furnace can be attributed to the accumulation of fine coke near the wall.