9 - Minimizing water and energy use in the batch and semi-continuous processes in the food and beverage industry

Abstract

Publisher Summary The minimization of water and energy use in batch and semi-continuous processes should be considered within a common modeling framework of time-dependent process operations. When dealing with continuous processes, only the flow rate and concentration limits of the existing process water streams need be considered. However, the systematic rationalization of water use in the batch process industry cannot simply be seen as an extension of the continuous case, because of the additional time dimension in batch processing systems. The use of storage tanks for spent water must be considered as a means of increasing the potential for reusing wastewater between various operations. These tanks can store water at different contamination upper bounds and supply it for reuse to other points in the plant anytime later. They can also be used to mix different streams to dilute highly-contaminated effluents to make them suitable for further reuse. Taking into account these aspects, various optimization techniques can be used to reduce the use of raw water. This chapter presents a novel methodological framework for wastewater reduction in batch processes, derives a formal mathematical model of the combined water reuse and energy recovery system in time-dependent processes, describes the model approach and optimization strategy, and applies the method proposed to industrial cases. The first case is the manufacture of concentrated juices and the second is beer production.