Bernd Maier, Carsten Dietrich, Jochen Büchs:
Correct application of the sulphite oxidation methodology of measuring the volumetric mass transfer coefficient k(L)a under non-pressurized and pressurized conditions
Food Bioprod. Process., 2001, 79(C2), 107-113
In this study, the effect of the reaction kinetics of sulphite oxidation on the experimentally observed volumetric mass transfer coefficient k(L)a in a stirred tank under non-pressurized and pressurized conditions, has been investigated. In contradiction to the assumptions made by many authors, it cannot be assumed that the oxygen concentration in the sulphite solution is at zero level. Neglecting the dissolved oxygen concentration leads to a systematic underestimation of the volumetric mass transfer coefficient especially at higher oxygen transfer rates. Additionally, if the sulphite oxidation methodology is applied under pressurized conditions an increase of the oxygen partial pressure can result in a chemical enhancement of the absorption process and therefore, in a rise of the observed volumetric mass transfer coefficient k(L)a. If the kinetics of the sulphite oxidation reaction are known these errors can easily be calculated. Consequently it is recommended that the reaction rate constant k(2) is measured prior to mass transfer experiments.
mass transfer, pressure, stirred tank, sodium sulphite