Motion Characteristics of Gas and Solids in the Conical Spouted Bed

The conical spouted bed has been widely use to dry or coat particles. To design and scale up conical spouted bed, it is of fundamental importance to have a detailed understanding of the motion characteristics of gas and solids in it.In this article, the movement of gas and particles in the conical spouted bed was recorded by High Speed Photography.

From the photographic recording of the initial stage of a spouted bed formation it was discovered that there were three sections in the bed at the initial stage: being gas flow column, particle arching, and solids circulation section. During normal operation phase the fountain region in the spouted bed was characterized by a repeated manner of gas stream-solids stream-gas stream. A diagram of solids-gas flow pattern classification in accordance with the gas velocity was developed from the high speed photographs taken at the spouted bed. The kinemtic features of solids and gas were identified and described for each of the five flow patterns. The longitudinal profile of the fountain region in the conical bed was determined from phtographs and three forms of prefiles were classified as “S”, “I” and “V” shapes, varying with the gas velocity.

Pressure measurements conducted in the spouted bed indicated that for a given bed level the maximum pressure was detected at the inteface between the fountain and annulus vegion, and the maximum fluctuation of pressure was in the bed central axis.

The results obtained from the investigation may offer useful information for the conical spouted bed may be helpful for industrial applications.