Sparger type influence on the hydrodynamics of the draft tube airlift reactor with diluted alcohol solutions

Abstract

The objective of this work was to investigate the influence of normal aliphatic alcohols (from methanol to n-octanol) and the gas sparger type (single orifice, perforated plate, and sinter plate) on the hydrodynamics of a draft tube airlift reactor. The results showed that the presence of alcohols led to both an increase in the gas holdup and reduction of the downcomer liquid velocity, in comparison to the values obtained in water. The type of gas sparger also changed the hydrodynamic behavior - the gas holdup increased with dispersion effectiveness, from single orifice to sinter plate, while the effect on the downcomer liquid velocity was in conjunction with the liquid phase properties. Simple correlations were developed to predict the gas holdup and the downcomer liquid velocity. Beside the gas superficial velocity, the proposed correlations include the surface tension gradient, as a unique parameter which represents the liquid phase properties, and sparger related variables: the ratio of the sparger's total openings area and the draft tube cross-sectional area and also orifice (pore) size of the sparger. © 2011 American Chemical Society.