Reducing process steam usage? What will happen to the water balance?

The paper considers the implications of reducing the process steam consumption on the water usage patterns in a cane sugar factory. The changes in liquid effluent production, condensate usage and injection water requirements are determined in factory water balances for several scenarios. The initial water balance is determined for a typical factory operating with minimal vapour bleeding from thc evaporators. The steam consumption for this factory configuration is approximately 50.6 steam%cane. Water balances are then determined for different factory configurations requiring reduced process steam consumption. These configurations include reduced ESJ flows, increased evaporator vapour bleeding to juice heaters, vapour bleeding to the pan stage and combinations thereof As steps are implemented to reduce process steam consumption, for example in factory cogeneration, the overall water balance is affected, resulting in increased quantities of water requiring disposal. The effluent water outflow increases from 17.4% on cane for the typical factory configuration to 41 % on cane for a factory configuration with a steam consumption of 35.9% on cane. A linear plot of these data shows that for every unit decrease in process steam%cane, there is a corresponding increase in the outflow water quantity to effluent of 1.5% on cane. These data apply to the conditions selected in the study. Practical strategies are given that can reduce the overall raw water usage and minimise effluent disposal requirements.