Performance of a freeze concentration pilot plant during the start-up phase

Abstract

In this paper are presented the findings obtained during the start-up of a freeze concentration pilot plant, that operated with suspension crystallisation and with simulated fruit juices. Solutions with different initial concentrations were tested, with and without acidification, to simulate fruit characteristics and behaviour. The experimental runs demonstrated that solution acidity has negligible effects on the process performance, whereas the results showed that the initial solution concentration influences the start-up duration. During this time, the solution concentration grows by about 10 °Brix, and the maximum quantity of ice content inside the crystalliser is always lower than 40% by weight. These findings can help to predict the performance of a freeze concentration plant and may facilitate achieving target concentrations in a more efficient mode. Taken together, the data suggest that the initial concentration of the processed juice influences start-up duration and the achievable final concentration.