1991 Volume 77 Issue 1 Pages 71-78
In order to clarify the combustion reaction when PC (Pulverized Coal) is blown into the tuyeres of blast furnace and the effects of resultant unburnt PC on in-furnace reactions, some fundamental experiments were carried out. The main results obtained are as follows.
(1) Most of PC blown through the tuyeres rapidly burns in the raceway, but part of PC may be carried out of raceway without being burnt.
(2) Unburnt PC tends to adhere to the softened and fused are bed. Unburnt PC adhering to the ore bed is consumed for the direct reduction of FeO, and effectively improves the high-temperature properties of ores.
(3) The gasification reaction rate of unburnt PC is larger than that of coke. The presence of H2 enhances the reaction, whereas that of CO inhibits it.
(4) Since unburnt PC is selectively gasified, the reaction rate of lump coke lowers, and thereby the degradation of coke in the raceway may be inhibited.
In this way, PC entering the blast furnace without being burnt was found to be effectively consumed. However, since the ash could built up in front of tuyeres, it is necessary to examine an actual blast furnace by sampling in-furnace materials to mitigate combustion conditions, to expand the range of usable quality of burden materials and to search possibility of blowing a great amount of PC.
