Hydrodynamics of pressurized spouted beds

Experiments were carried out in a pressurized spouted bed with pressures up to 345 kPa. The minimum spouting velocity was found to decrease with increasing pressure. Comparison of the experimental minimum spouting velocities with the Mathur-Gishler (1955) equation gave unsatisfactory agreement. The maximum spoutable bed height, H-m, and spout diameters increased with increasing bed pressure. The McNab and Bridgwater (1977) equation consistently over-stimated H-m for large or heavy particles and underestimated H-m for small particles, with the deviations between the predicted and experimental values being greater at high bed pressures. Although the McNab (1972) equation gave good predictions of average spout diameters for beds at ambient pressure, it gave poor predictions at elevated pressures, with errors up to 66%. For a given fluid-solid combination and column geometry the longitudinal pressure profile in the annulus was found to be independent of bed pressure. Five fairly distinct now regimes were observed, and spoutability could be improved by increasing bed pressure.