A quantitative measure of coke abrasion.

Abstract

The size degradation of coke and model coke materials in tumble drums has been studied. For the model materials it was shown that current tumble strength indices are affected by size degradation due to both volume breakage and abrasion. The poor correlation between these strength indices can in part be explained by differences in the relative importance of these two mechanisms in different drums. A new procedure using presta-bilized material was developed in which size degradation was controlled by the abrasion mechanism alone. It was found that, by performing measurements in this manner, abrasion of the model coke materials could be represented as a first order rate process. The abrasion rate constant showed a strong relationship with material strength as measured by compressive strength.Seven cokes with a relative abrasion resistance varying from very low to high were examined using this procedure. In all cases, the abrasion process was well represented by the first order rate equation and the measured values of abrasion rate constant were reproducible to±3%. The abrasion rate constant was found to increase with increasing coke size. Abrasion rate constants measured in ASTM and MICUM drums correlated well and there is potential to relate the rate constant to fundamental coke properties.