Degradation of Coke due to Gasification

Abstract

Experiments on the degradation of cokes due to gasification with CO₂ under the presence of ore and alkali were carried out.
Following results were obtained:
1) The degree of gasification increases with the increase of blending ratio of ore, and this brings about the corresponding decrease of strength.
2) The presence of alkali increases the chemical reaction rate by its catalytic action, and results in the localization of reaction sphere to the surface zone of a coke particle. It also results in the conservation of a sound core and in the apparent alleviation of the degradation of the particle as a whole (compared to that without alkali).
3) Coke B made from a specially inferior coal blend shows a steep fall of strength after reaction at a overall gasification ratio of 10% or so, and this feature becomes remarkable under the presence of alkali, while the strength of coke A made from an ordinary coal blend decreases gradually as the degree of reaction increases.
The difference between coke A and B seems to suggest that “critical degree of gasification”, at which it may disintegrate, of the latter is essentially smaller than that of the former. It also seems to suggest that the remarkable degradation of coke B probable at some high degree of reaction may be at least one of the reason of its severe disintegration in the experimental blast furnace (in the 26th run).