Pinch Analysis of an Industrial Milk Evaporator with Vapour Recompression Technologies

Abstract

The present study focuses on applying Pinch Analysis to an industrial milk evaporator case study. Modern milk evaporators are typically integrated using both mechanical and thermal vapour recompression technologies as the primary means for attaining a high level of energy efficiency. A significant step change in energy efficiency for milk evaporators is achieved in this study by modifying the set-up of the concentration processing pathway in combination with an improved heat exchanger network design. To effectively perform the Pinch Analysis, a validated mass and energy balance model of the milk evaporator case study has been implemented in an Excel spreadsheet from which appropriate stream data may be extracted. In particular the Grand Composite Curve plays a critical role in identifying where vapour recompression units, which are a type of heat pump, may be applied to reduce thermal energy use by as much as 67 %, which represents an annual utility cost saving between 640 – 820 k$/y.