Hydrodynamics of shallow, conical spouted beds

Experiments were conducted with shallow beds, in the presence of atomizing air injected into the base, under the following conditions: Particles — urea, sulphur coated urea, polyethylene, polyformaldehyde and polystyrene; particle diameters (dp) – 2.1 to 2.8 mm; cone angle – 60°; cylindrical bed diameter (D) – 0.24 and 0.45 m; bed height (H) – 0.24 to 0.40 m; orifice diameter (di) – 21 to 35 mm; main spouting air (Qs) ≤ 37 L(actual)/s; atomizing air (Qa) ≤ 0.87 L(actual)/s. The minimum spouting velocity is well represented by: Ums = 13.5 (2gH)0.5 (dp/D')1.17 (D'i/D')0.372 (H/D')−0.148 [(τp ‐ τ)/τ]0.289 where D' and D'i denote the modified column and orifice diameter, respectively. Qa, which affects D'i, significantly influenced the air velocity in the spout, but not the pressure profiles in the annulus. Morgan and Littman's (1980) correlation could be adapted to predict the experimental pressure profiles in the annulus.