Hydrodynamic study of two and three-phase airlift reactors

Abstract EN

The experimental investigations on the hydrodynamic performance of both two and three-phase gas liquid-solid in 171 and 135-liter external loop airlift reactors have been conducted.

The purpose of the work includes the development of new hydrodynamic correlations concerning the riser and down-comer sections 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 holdup in the riser (R) and in the down-comer (VLD), 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 factor to differentiate the reactors (i.e.

Ad / Ar = 0.54 meant the larger reactor, Ad / Ar = 0.25 meant the smaller reactor).

The effect of the (Ad / Ar) factor on the (r, d, 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 d versus r.

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.