HYDRODYNAMICS OF PRESSURIZED SPOUTED BEDS

Experiments were carried out in a pressurized spouted bed with pressur es up to 345 kPa. The minimum spouting velocity was found to decrease with increasing pressure. Comparison of the experimental minimum spout ing velocities with the Mathur-Gishler (1955) equation gave unsatisfac tory agreement. The maximum spoutable bed height, H-m, and spout diame ters increased with increasing bed pressure. The McNab and Bridgwater (1977) equation consistently over-stimated H-m for large or heavy part icles and underestimated H-m for small particles, with the deviations between the predicted and experimental values being greater at high be d 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. Fi ve fairly distinct now regimes were observed, and spoutability could b e improved by increasing bed pressure.