A theory for predicting the maximum spoutable height in a spouted bed

A theory is presented for predicting the maximum spoutable height, in a spouted bed where fluidization of the annular solids limits the penetration of the fluid jet entering the bed. The quantity (Hmds/(D – d ) is found to be a function of ds/Dc only for spherical particles and \[ {{H_m d_S }} {{(D_c^2 ‐ d_S^2 )}} = 0.345( {{{d_S }} {{D_c }}} )‐ 0.384 \] where the spout diameter is calculated using McNab's correlation(7). Insertion of McNab's correlation into Equation (1) shows that Hm is proportional to D and the effect of dp on Hm varies from d to d as the particle Reynolds number increases assuming 1 ≥ (ds/D ). Using experimental value of ds, the calculated values of Hm differ from the experimental ones by 8.5% on average. When small particles are spouted with air, the penetration of the jet is limited by the formation of a slug in he spout and the theoretical value provides an upper limit for Hm.