Effects of agitation rates over metastable zone width (MSZW) of concentration for cane sugar crystallization

The aim of this work is the experimental measurement of metastable zone width (MSZW) of concentration for sugar cane solutions by means of the polythermal method coupled with an image acquisition system, taking into account the effects of agitation rate and temperature, which represents a key novelty, since this is the first work that considers both variables experimentally. A split plot experimental design was followed with two factors, temperature with four levels (40, 50, 60 and 70 °C), and agitation rate with 3 levels (150, 250 and 350 rpm); the response variables were density (as a measure of concentration) and crystal size distribution. The results allow to demonstrate that agitation rate does not exhibit a statistical effect on the MSZW for the crystallization of cane sugar, attributing the formation of nuclei and their growth to effects by changes in the temperature. This contributes to better understanding of the phenomenological behavior occurring in sugar cane crystallization.

Keywords: MSZW, agitation rate, crystallization, cane sugar, concentration.