Residence time distribution of solids in a fluidised bed

The present work involves an experimental investigation on residence time distribution of solids in a continuous fluidised bed for uniform size and for binary solid mixture at different dilutions. The column was tested for improvement in performance with increase in dilution. The effect of gas flow rate, solids flow rate and dilution on the: first, second and third moments and on F-curves have been determined. Fractional tank extension model fits the experimental data. High values of N as dilution increases, indicates reduced solids mixing, thus reducing spread of residence times, giving rise to more uniform quality of product. The work finds importance in that similar improved performance of the column using internals inside the bed can be obtained by using a mixture of solids rather than uniform size.