1982 Volume 22 Issue 4 Pages 287-296
When the productivity of No. 2 blast furnace at Sakai Works, Nippon Steel Corporation, was cut down from 2.08t/d•m3 because of the economic deterioration in Japan in the latter half of 1970's, coke was sampled at the tuyere level seven times in the course of the cutdown.
On the basis of the test result of the properties of coke sampled, the followings were concluded:
(1) As the production rate decreases, the point of the maximum temperature in the raceway moves toward the tuyere and the temperature of the dead-man decreases.
(2) Coke becomes fragile because of the long time exposure to high temperatures at the lower part of the furnace. Therefore, the amount of coke fines in the raceway increases with increasing kinetic enemy of blast, and in consequence, gas flows upward rather along the wall side than in the center.
On the other hand, the decrease in the amount of coke fine, which is brought about by the decrease in the kinetic energy of blast, results in a smooth operation which is attributed to the uniform gas distribution. However, in the case of lower kinetic energy of blast, the temperature of the deadman decreases and, consequently, softened and half-melted materials form in the region.
