Sparger Type Influence on the Volumetric Mass Transfer Coefficient in the Draft Tube Airlift Reactor with Diluted Alcohol Solutions

In this work, the influence of addition of normal aliphatic alcohols (from methanol to n -octanol) and the gas sparger type (single orifice, perforated plate, and sinter plate) on the volumetric mass transfer coefficient in a draft tube airlift reactor was investigated. The results showed that the addition of alcohols from methanol to n -hexanol led to an increase in the volumetric mass transfer coefficient, in comparison to water, while n -heptanol and n -octanol had the opposite effect. The influence of the gas sparger was dominant at low superficial gas velocities. At higher gas velocities, the liquid-phaseproperties and the sparger type, being opposite in effect on mass transfer, annulled one another’s influence. Also, simple correlation was proposed to predict the volumetric mass transfer coefficient. The analysis of the parameters in the proposed correlation showed that the liquid-phaseproperties, expressed through the surface tension gradient, and the gas sparger type, mainly through initial bubble size, had a marked influence on the mass transfer.