Prediction of Fluctuation, Expansion Ratios and Gas Hold Up in a Three Stage Gas-solid Fluidized Bed – A Statistical Approach

Abstract

Multistage fluidized bed has shown greater performance than the single stage in terms adsorption efficiency, recovery efficiency etc. Thus, experiments have been carried out in a three stage gas-solid fluidized bed. The hydrodynamic characteristicssuch as fluctuation ratio, expansion ratio and gas holdups have been studied. The dependency of these quantities with the system variables like particle size, initial static bed height and superficial gas velocity in each stage of a three-stage fluidized bed have been analyzed. It has been found that both fluctuation and expansion ratios are inverse functions of particle size and static bed height whereas a direct function of superficial gas velocity. However the gas holdup is a direct function of all the three operating parameter.It has also been observed that bed fluctuation and expansion goes on decreasing from lower bed to the upper bed. Further correlations have been developed for all the three stages for fluctuation ratio, expansion ratio and gas holdup using statistical analysis. It has been found that the experimental values of the responses agree well with the values predicted from the models.