Hydrodynamics and oxygen mass transfer characteristics of petroleum based micro-emulsions in a packed bed split-cylinder airlift reactor

Abstract

-The effects of aeration velocity and liquid properties on the pertinent hydrodynamic and mass transfer parameters in a split-cylinder airlift reactor (with and without packing) were examined. Four different oil-in-water micro-emulsion systems containing kerosene, heavy naphtha, light naphtha and diesel as the oil at the concentration of 7% (v/v) were used in the experiments and the results were compared with pure water. The experimental results showed that the gas (air) hold-up and the volumetric gas-liquid oxygen transfer coefficient values for the micro-emulsion systems were usually greater than those of pure water. The packing installation increased the overall gas-liquid volumetric mass transfer coefficient by increasing the flow turbulence and Reynolds number, compared to the unpacked column. The packing increased the gas hold-up and decreased the bubble size and liquid circulation velocity. Furthermore, two empirical correlations were developed to predict the overall gas hold-up and volumetric oxygen transfer coefficient. A good agreement was observed between the experimental and correlated data.

Distribution of Mixing Efficiency in a Split-Cylinder Gas-Lift Bioreactor with ImmobilizedYarrowia LipolyticaCells Used for Olive Oil Mill Wastewater Treatment

“…Gas-lift bioreactors are provided with various devices which promote the circulation of the broths as internal or external-loop (split-cylinder or draft tube internal-loop, with or without impeller driven loop, packed bed, external loop, etc.) (Chakraborty et al, 2009;Moraveji et al, 2013). Because this flow pattern exposes the cells to fluctuating growth conditions, the uniform distributions of the nutrients, dissolved oxygen concentration, temperature, or shear stress magnitude represent the main factors controlling the gas-lift bioreactors performance.…”