ELABORATE CLASSIFICATION OF FLY-ASH PARTI CLES BY BENCH-SCALE AIR CYCLONE

Experimental studies were conducted on the classification of flyash pa rticles by use of a modified cyclone with movable 50% cut size on a be nch scale. The 50% cut size of cyclone changed from 1 to 10 mu m by th e change of apex cone height and blow-up flow rate. When the height of the apex cone was higher at a constant blow-up flow rate, the 50% cut size increased. The reason for this was due to the fact that a decrea se in the effective cross-sectional area near the inlet of the dust bo x gave rise to the increased average upward fluid velocity. In the cas e of blow-down, two kinds of different-sized fine particles were obtai ned simultaneously. When the blow-down flow rate was 5%, collection ef ficiencies of 4 and 28% were obtained with mean particle diameters 2 a nd 6 mu m respectively. When both the blow-down method and a movable g uide plate at the cyclone inlet were used, particles of average diamet er of 1.5 mu m were collected. Although the cyclone diameter was 400 m m, elaborate classification of flyash particles was achievable.