Abstract
Three issues fundamental to the evaluation of axial dispersion coefficients in a liquid fluidized bed, the variation of the estimated value of the coefficient with the bed height and the tracer residence time in residence time distribution (RTD) experiments, the effect of particle density, and the influence of the solute diffusivity, were addressed. Experimental results cast doubt on the assumption that the axial dispersion coefficient could be regarded as constant in the case of short fluidized beds. A quantitative criterion to permit accurate estimation of the coefficient in RTD experiments was proposed.