Wall-to-bed mass transfer in three phase fluidized beds in the presence of angled disc promoter

Abstract

Mass transfer coefficient data were computed from measured limiting current values obtained at point electrodes fixed flush with the inner wall of an outer cylinder of three phase fluidized bed electrochemical reactor in the presence of an angled disc internal. Nitrogen was used as gas phase. Glass balls of different diameters were used as solid phase. The liquid phase was an electrolyte that belonged to the ferricyanide-ferrocyanide redox system. Enhancement in mass transfer coefficient obtained in the case of three-phase fluidized bed in the presence of angled disc internal was upto 14 fold in comparison with the homogeneous flow of electrolyte in plain pipe. The mass transfer coefficient data thus obtained were found to increase with increasing gas velocity, pitch and disc diameter. An increase in disc angle resulted in a decrease in the mass transfer coefficient. The influence of liquid velocity, promoter rod diameter and particle diameter on mass transfer coefficient was found to be insignificant. The entire mass transfer coefficient data obtained in the present study were subjected to regression analysis and useful correlation equation was obtained.