Configuring quintuple evaporator stations to provide high levels of steam efficiency in Australian factories

Australian sugar factories typically use Robert evaporators in quintuple sets for juice evaporation and large, unstirred batch pans for crystal sugar production. These two equipment arrangements present several challenges for Australian factories to implement large reductions in process steam consumption, for example, by operating the pans on low pressure vapour, such as vapour from the second or third effect of the evaporator station. This paper considers the impact on the quintuple evaporator station of the variable vapour demand of the batch pans and investigates the changes needed to ameliorate the adverse impacts and to increase the pressure of the vapour supply to the pan stage. The solutions consider the flashing of vapour from condensate, the use of bleed vapour and condensate for juice heating, replacing some Robert evaporators with falling-film tube evaporators, measures to better control the evaporator set, and ways to limit the extent of sucrose degradation in the evaporators.