Mechanism of Ice Growth in a Batch Crystalljzer with an External Cooler for Freeze Concentration

抄録

Two mechanisms of ice crystal growth were found in a batch crystallizer with an external cooler, that contained a large amount of ice crystals. With the first mechanism, the ice crystals grew larger by the usual kind of growth, governed by heat or mass transfer resistance, and with the second, the ice crystals agglomerated and the agglomerate fused into a very large ice crystal (1-3mm in diameter). The conditions in which the second mechanism prevails were investigated extensively. The second mechanism occurred not because of the high concentration of ice crystals in the crystallizer but because of long residence time. Large ice crystal agglomerates were not produced when extremely small ice crystals were formed in the crystallizer at the start of the experiment.