On the bleaching kinetics of vegetable oils - experimental study and mass transfer-based interpretation

This study focuses on the systematic investigation of the parameters involved in adsorptive vegetable oil bleaching. These parameters range from the quality of oil and bleaching conditions chosen (e.g. amount and activity of clay, initial water content, temperature, pressure) to the effects of the different reactor systems used (agitated vessel, bubble column) on the kinetics. The study of the latter aims to optimise the type and intensity of power input. The most efficient process was shown to take place in the bubble column reactor. The findings result in a kinetic model for the transport phenomena of the pigments from the oil phase into the clay. The model splits the effects in phenomena due to mass transfer resistances inside and outside of the clay particle. By doing so it is possible to describe the bleaching kinetics in dependence of the amount of clay added and on the size of the external mass transfer resistance, which is influenced by the power input into the reactor. Thus a on model-based analysis of the effects as well as the optimisation of the bleaching reactor are made possible.