Influence of Operating Conditions and Physical Properties of Liquid Medium on Volumetric Oxygen Transfer Coefficient in a Dual Impeller Bioreactor
Keywords:Stirred bioreactor, agitation, air flow rate, dissolved oxygen, glucose concentration, volumetric mass transfer coefficient of oxygen
AbstractThe objective of this research was to study the effects of process variables on the volumetric mass transfer coefficient of oxygen, KLa, in a stirred bioreactor using the static gassing-out method. In this study, various process conditions were chosen, including 3 parameters, namely, concentration of glucose in medium (10, 15 and 20 g/l), air flow rate (1, 1.25, 1.5 and 1.75 vvm), and agitation rate (300, 400, 500 and 600 rpm). From the results, it was found that the KLa increased with increasing air flow rate and/or speed of agitation, but decreased with increasing concentration of glucose in medium. The maximum KLa occurred when the concentration of glucose in medium was the least (10 g/l), with an air flow rate of 1.75 vvm, and an agitation rate of 600 rpm. Correlations have been developed for the estimation of volumetric mass transfer coefficients at various process conditions for medium with different glucose concentrations. The exponent values representing dependence of KLa on the process conditions were then compared with literature values.
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