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Oxidation of glucose by homogeneous glucose oxidase was performed in rectangular bubble column reactor at 40 °C, ambient pressure and pH of 5.5 while superficial gas (oxygen) velocity was varied in the homogeneous and transition regime in the range of 0.0014-0.0112 m s-1. Effect of superficial gas (oxygen) velocity on the apparent reaction rate and its parameters was determined and it was observed that the apparent reaction rate on the basis of volume of the liquid increased with increasing the superficial gas (oxygen) velocity. The apparent reaction rate was assumed to be in the form of Michaelis-Menten equation and its apparent kinetic parameters were evaluated by the nonlinear regression method. [ABSTRACT FROM AUTHOR]

Abstract: Determinations of pertinent hydrodynamic and mass transfer parameters were carried out inside draft tube internal loop airlift bioreactor (DTAB) containing water in diesel (W/D) microemulsions with water to diesel volume ratio (φ) in the range 2.5–40%. For comparative purposes, data for diesel and water was also obtained. Increase in φ of the microemulsion systems up to 40% or increase in the amount of surfactant used to make the microemulsions resulted in a decrease in the values of ɛ g and k L a, which was attributed to the increase in the viscosity of the microemulsions. This viscosity was found to be a more suitable correlating parameter than φ. Increase in the value of φ of the W/D microemulsion resulted in a decrease in the values of liquid velocity for u gr up to 0.032m/s. At higher gas velocities, similar values were obtained for all the microemulsions. On the other hand, increase in φ of the W/D microemulsion resulted in increase in both the circulation time and mixing time values obtained inside the DTAB, although the difference was more pronounced at lower values of u gr. Suitable empirical correlations relating ɛ g , k L a, , circulation time and mixing time to riser superficial gas velocity (u gr) and kinematic viscosity were presented. The downcomer holdup data for diesel and W/D microemulsions was related to the riser holdup data using a single correlation. [Copyright &y& Elsevier]