Effect of feed rate and classifier height on air classification

The effects of varying the height and number of stages and feed rate for nonpulsing, passive-pulsing, and active-pulsing air classifiers is studied for the separation of complicated particle mixtures. All of the air classifier configurations tested achieve high (>94%) maximum separation efficiency. Increasing height is found to increase the range of air flow over which separation efficiencies greater than 90% are achieved. Decreasing feed rate has a similar effect. For each of the three classifiers studied--nonpulsing, passive pulsing, and active pulsing--the tallest classifiers at the lowest feed rates achieved the broadest efficient separation range. Results indicate that the passive-pulsing air classifier performs better than the active-pulsing air classifier, which in turn performs better than the nonpulsing air classifier.

Duke Scholars

Author J. Jeffrey Peirce Civil and Environmental Engineering