| 摘要 |
PURPOSE:To increase the efficiency of contact between the particles of the dried substance and cool air and improve cooling effect by a method wherein the whirling stream of the cool air is generated at the lower part of a drying tower, drying the sprayed particles to be dried by hot air, and the dried particles are cooled by contacting with the cool air within the range of 1-2m/sec of air speed. CONSTITUTION:The mist of the slurry-like particles of the substance to be dried is supplied from a sprayer 12 into the drying tower 10 to contact them with the hot air blown out of blow-off ports 11 while the particles are dropping in the drying tower 10, while the dried particles descend through the drying tower 10 to a cooling part 13 for cooling by contacting them with the whirling stream of the cool air. The cool air is blown from each supplying ports 15 at the cooling part 13 into the tangential directions to form the whirling stream of the cool air ascending under whirling into the circumferential direction, while the descending particles are cooled by descending them under whirling gradually and, thereafter, they are discharged out of a discharging port 18. The axial flow speed of the whirling stream of the cool air is suitable for cooling when it is within the range of 1-2m/sec in case the average grain diameter is 400- 500mum, the bulk density is 200-300kg/m<2> and the cool air temperature is 20 deg.C. |
