Performance of various distributor designs in a gas-solid fluidized bed

The applications of fluidization are far reaching. Some of the applications are combustion, gasification, drying, exfoliation and coating. However, only a few publications are available on fluidized beds that operate with Geldart Type-D particles and its respective distributors. This study focuses on fluidization of Geldart Type-D particles with three novel design of gas distributor, designated as Square Pitch Distributor (SPD), Circular Pitch Distributor (CPD) Semi-Circular Pitch Distributor (SCPD). The analysis of the results indicate that for the given bed characteristics, SPD shows better performance. Lower pressure drops and better fluidization uniformity are obtained. The distributors are perforated plate type with 4 mm holes, giving a total open area ratio of 13%. The holes are laid out in square and circular pitch of 10 mm. The bed was filled with Geldart D spherical PVC particles with a mean diameter of 5.87 mm and a density 858.8 kg/m³. Experiments are conducted by using superficial velocity up to 7.2 m/s and the range of particle loading is 0.5 kg to 2.0 kg. The pressure drop across the bed is measured by a digital manometer and the fluidization quality is assessed through physical observation. The maximum bed pressure drop values obtained for the distributors are 0.4122 kPa for SPD, 0.463 kPa for CPD and 0.5138 kPa for SCPD, with minimum fluidization velocities of 3.475 m/s, 3.588 m/s and 3.492 m/s respectively. In conclusion, SPD is found to have the best hydrodynamic characteristics and is most suited for use in gassolid fluidized beds.