EXPERIMENTAL DETERMINATION OF THE VOLUMETRIC MASS TRANSFER COEFFICIENT

The volumetric mass transfer coefficient (k L a) is often used in order to compare the efficiency of bioreactors and as an important scale-up factor. In bioreactors, a number of methods are available for estimation the overall volumetric oxygen mass transfer coefficient: the dynamic method, the steady-state method based on a preliminary determination of the oxygen uptake rate, the gaseous oxygen balance, the carbon dioxide balance. Each method provides a different estimation of the value of k L a. We examined the sensitivity of the various methods and compare the k L a values obtained in order to select the most suitable method as a function of the type of bioreactor used. In this work we applied dynamic gassing-out method for measuring the volumetric mass transfer coefficient k L a in three type gas-liquid reactors (stirred tanks, bubble columns and airlift). Тhe aim of this work is on the basis of our experimental data to obtain several correlations for evaluation of k L a.