Mass Transfer in Agitated Liquid-Solid Systems

Abstract

The authors performed experiments on the solution of solid particles in agitated liquids in a series of geometrically similar agitators. A great variety of solid particles, including several kinds of spherical crystals, whose particle size, shape and density varied over a wide range were used as the solid samples. Pure water, dilute hydrogen chloride and aqueous solutions of gelatine, polyvinyl alcohol, sucrose and glycerine of various concentrations were used as the liquids. Several methods for determining the rate of solution of solid particles were considered, and the analysis of the data was performed in terms of the mass transfer coefficient. As for the experimental results on the agitation process, it was found that the physical properties of the solid particles, i.e., the difference in density between the liquid and the solid, the size and shape of the particles, as well as the viscosity and the density of the liquid were important factors controlling the rate of mass transfer. Between the agitator speeds of Nf and Nₐ all the data were correlated by the following dimensionless equations. For solid particles with an unknown surface shape factor, and for solid particles with a known surface shape factor, where These equations represent the general correlation of the variables involved in determining the magnitude of the rate of mass transfer in agitated liquid-solid systems, and are used to estimate the mass transfer rate for any liquid-solid combination in a series of geometrically similar vessels and impellers.