Experimental study on mixing and precipitation in a fluidized bed reactor

Visualization experiments using an acid–base decolourization technique with phenolphthalein as indicator are performed in order to investigate the influence of operating parameters and feed tube position on the mixing efficiency of reacting fluids in the absence and presence of the fluidized solid phase composed of glass micro balls of different diameters. The precipitation of calcium carbonate as calcite is then experimentally investigated in the same cylindrical fluidized bed reactor where nucleation, crystal growth and agglomeration take place simultaneously. In all experiment narrow particle size distributions are obtained. An increase of fluid velocity increases the agglomerate particle size principally due to the intensification of the agglomeration process. At the same time, the carryover particle size is increased. The maximum capacity of the fluidized bed reactor is experimentally obtained at the intersection of agglomerate and carryover particle size variations.