Three Phase Fluidized Bed Essay

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Gas and liquid holdups in a three phase fluidized bed in the presence of an angled disc promoter Abstract Experiments were conducted to investigate the effect of pertinent dynamic and geometric variables on gas and liquid holdups in a three-phase fluidized bed in the presence of an angled disc promoter. The gas holdup was found to be increasing with an increase in pitch, disc diameter and disc angle. The gas holdup decreased with increase in particle diameter. The liquid holdup was found to be decreasing with an increase in pitch, particle diameter and disc angle. The liquid holdup increased with increasing disc diameter. The data on gas and liquid holdups were correlated using least squares regression analysis to obtain useful correlations. Keywords: Holdup, angled disc promoter, three phase fluidized bed. Nomenclature dk disc diameter [m] dp particle diameter [m] Dc diameter of the column [m] g acceleration due to gravity [m/s2]…show more content…
2d shows the gas holdup data plotted against superficial liquid velocity for three particle sizes viz., 2.93, 4.24 and 5.62 mm in the case of angled disc promoter at a constant superficial gas velocity Ug = 0.0234 m/s. The plots reveal that the gas holdup decreased with the diameter of particles. This trend is also evident from its inset Fig.2d*. An increase in liquid velocity causes the fluidized bed to expand. As the particle diameter is increased, at a given liquid velocity more number of solid particles present in the given volume of the bed. This causes a reduction in the gas holdup. This mechanism is in accordance with the trends observed in this graph. In case of increasing gas velocity at a fixed liquid velocity, the variation in bed expansion would be insignificant. Because, the suspension of particles in the bed is mainly due to liquid momentum and the gas momentum hardly adds to it. Hence, the effect of particle diameter in this case can be expected to be

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