Experimental Study on the Relationship between Carrier Gas Temperature and Entrainment Characteristics of Ultrafine Silicon Powder in Fluidized Bed

Abstract

The effect of carrier gas temperature on entrainment characteristics of Geldart group C powder from solid mixtures (groups A and C) were investigated in a fluidized bed, which was 40mm in inner diameter and 150mm in height. Silicon powder of mean size 2.2μm was adopted as entrained material (group C), hollow alumina pellets of mean size 775μm were used as coarse particles (Group A), and industrial nitrogen (99.5%) was applied as carrier gas. mixture of silicon powder (50g) and alumina pellets (50g) were used as bed materials. The nitrogen flow rate varied from 1.5m3/h to 2.5m3/h, and the nitrogen temperature varied from 60°C to 120°C. The experimental results revealed that the bed materials were in good fluidizaton state at all of the experimental conditions. At given nitrogen flow rate, the entrainment rate constant and powder gas ratio increased at the same rate as the nitrogen temperature increased. When nitrogen temperature increased from 60°C to 120°C, the entrainment rate constant and powder gas ratio increased over 140%. The phenomena indicted that increasing carrier gas temperature was an effective method to improve entrainment characteristics of ultrafine powders.