HYDRODYNAMIC STUDY OF TWO an‎d THREE-PHASE AIRLIFT REACTORS

The experimental investigations on the hydrodynamic performance of both two and three-phase gasliquid-solid in 171 and 135-liter external loop airlift reactors have been conducted. The purpose of thework includes the development of new hydrodynamic correlations concerning the riser and down-comersections of the airlift reactors. In the two-phase study, tap water is used as the Newtonian medium. While in the three-phase study different quantities of paper are added in xanthan solution of water. The gas holdupin the riser (eR) and in the down-comer (eD), the liquid circulation velocity in the riser (VLR) and in the down-comer (VLD) are determined as function of the superficial gas velocity (VGR).The ratio of the cross-sectional area of the down comer to the riser (Ad/Ar) is used as a scale-up factorto differentiate the reactors (i.e. Ad/Ar = 0.54 meant the larger reactor, Ad/Ar = 0.25 meant the smallerreactor). The effect of the (Ad/Ar) factor on the (er, ed, VLR) parameters have been studied for different systems.The dependency of down-comer gas hold-up on the riser hold-up for different systems is computed and the new correlations were obtained by means of linear fit of ed versus er.In general, the addition of different quantities of paper on air-water- xanthan system leads to significant simulation of gas hold-ups and liquid circulation velocities for the study of the three-phase aspects of the hydrodynamics of airlift reactors.