Are there ways to increase the productivity of batch high-grade strike pans?

Australian sugar factories mostly use batch pans for high-grade massecuite production and, for many factories, the main strike pans are of large massecuite capacity e.g. 200 t, and not stirred. The productivity of these pans is affected by the supply pressure of the heating steam, the head-space pressure, the set-point value for steam rate to the calandria, the purity and dry substance of the feed materials, and the circulation characteristics attributable to the pan design. A model was developed to examine the influence of these parameters on the productivity for A and B massecuite boilings. Application of the model has shown that the typical steam rates used for A and B massecuite boilings often exceed the steam rate required for evaporation and crystallisation. Modelling indicates that the boil-on rate of pans can be maintained using lower steam rates if adequate circulation can be maintained. Boiling at higher temperatures is effective in increasing the boil-on rate. The ‘best practice’ batch-pan designs are shown to be able to run-up to pan full using 140 kPaa steam supply, given typical vacuum in the head space.