Design Parameter Effects on Expansion in Fluidized Beds with Inserts

The effect of some design parameters on the expansion of particles has been studied in a fluidized bed of 300 mm diameter. Four distributors were examined; three perforated plates, each perforated by holes of 0.8 mm in diameter but different hole densities at 6 mm, 9 mm and 12 mm pitch, and a porous plastic distributor 17 mm thick. Particles of different materials in the Archimedes number range from 100 to 10 5 were fluidized. The inserts were held vertically as arrays. All experimental data for four distributors were correlated within experimental error by the equation:$$\Big({{U‐U_{mf}} \over {U_0‐U_{mf}}} \Big)=\Big({{e‐e_{mf}} \over {1‐e_{mf}}} \Big)^{(1.28+0.00033P^3)}$$where U, U mf , U 0 are the gas velocity, velocity at minimum fluidization and real or apparent terminal velocity, while e is the bed porosity and e mf is the porosity at the condition of minimum fluidization. P is the hole pitch of perforated plate distributor in millimeters.