Hydrodynamic and axial mixing studies in asymmetric rotating impeller column at high dispersed to continuous phase ratios

In the present work, hydrodynamics characteristics such as dispersed phase holdup (εD), Sauter mean diameter (d32), drop size distribution (DSD), and continuous phase axial mixing was investigated in an asymmetric rotating impeller column (ARIC). Water – heavy normal paraffin (HNP) liquid system was used in ARIC to carry out the experiments. The effect of operating parameters such as impeller speed (N), superficial velocity of the continuous phase (Vc) was investigated. Experiments were performed at several dispersed to continuous phase (O/A) ratios. Volume displacement method and an image analysis technique were utilized to investigate the εD and d32, respectively. The pulse tracer technique was used to study the axial mixing in the continuous phase. The εD and d32 were strongly influenced by the impeller speed. More than 50% increase in εD was noticed when impeller speed increases from 100 to 350 rpm. The increase in dispersion coefficients (Dc) is observed with impeller speed. Whereas, it was noticed that O/A has a significant impact on Dc. About 80% decrease in Dc was observed when O/A increases from 5 to 25. The generalize equations have been developed for the prediction εD, d32, and Pec. [Display omitted] •Hydrodynamics and axial mixing studies of ARIC at high O/A ratio.•Drop size and holdup were found largely dependent on impeller speed.•Continuous phase axial mixing in ARIC is lower at a high O/A ratio.•Developed correlations to predict holdup, drop size, DSD, and Peclet number.