Grinding characteristics of coal and petroleum coke/coal blends on utilization for combustion

Petroleum coke (PC) blend with coal is an attractive feedstock for combustion process. The present work investigates the grinding characteristics of PC blend with coal in a laboratory ball mill to meet an industrial tube mill conditions. Tests were carried out using a laboratory batch ball mill for optimal production of -200mesh size product. The ground products at different combinations were subjected to sink-float tests. Experimental results suggested that the petcoke with coal at 5.0% blend ratio was optimum for generation of -200mesh size product. It was also observed that increasing coal/petcoke blend ratio beyond 5.0% leads to a decrease in -200mesh size generation. The better performance could be achieved at the blending ratio of 5%, perhaps resulting from the synergistic effect of the blends. With the aforementioned blend ratio, the optimal condition of the milling time was found to be 3h. The percentage of coal to the total charge and percentage of petcoke to the total charge of the ball mill product at various blends were also calculated for all the blends and at all grinding time intervals. The results obtained could provide a useful insight to predict the industrial mill performance.