A technique for contacting gases with coarse solid particles

Abstract

Abstract Although coarse, uniformly sized particles are not amenable to fluidization, it has been found possible by use of either gases or liquids to impart a regular cycling motion to a bed of this type of material in which the solids are rapidly carried upward by the fluid in a central well‐defined core within the bed. The particles move uniformly downward in the annular space surrounding the core, thus providing dense‐phase countercurrent contact between the fluid and the solids. There is no wall separating the core from the annulus. This method is called the spouted‐bed technique. The effect of column diameter, fluid inlet diameter, bed depth, and physical properties of solids and fluids on spouting behavior has been investigated. The minimum fluid velocity required for spouting has been correlated, and the flow pattern of the fluid and of the solids has been stuided. The technique has been applied to the drying of wheat.