Evaluation of Various Air-Swept Coal Classifiers

摘要

A twin cone classifier, an expansion chamber type classifier and a new centrifugal classifier recently developed by Hukki of Finland have been tested for coal grinding applications in a pilot scale air swept ball mill circuit. The centrifugal classifier was also tested in the stand alone mode using an open circuit air swept ball mill to prepare the classifier feed. Data from these were analyzed to give size selectivity information for each classifier and to determine the effect of classifier design on the specific energy requirements of the air swept ball mill circuit. Results of the evaluation indicate that the centrifugal classifier is capable of providing comparable (or superior) classification efficiency over a broader range of operating parameters than the other classifier designs. The specific energy requirements of the air swept ball mill circuit for producing a boiler grind were similar for all three classifier designs, however the centrifugal and twin cone classifier circuits produced a greater range of circuit product size distributions. For product sizes suitable for kiln firing, the centrifugal classifier circuit required lower specific energies than the twin cone classifier circuit when the circuit feed was a typical industrial-type 1-1/2'' x 0 size distribution. (ERA citation 07:045643)