Energy and exergy analysis of a milk powder production system

Milk powder production is a process that requires high energy, especially for evaporation. Recently, reducing energy use has been gaining importance by increasing energy and exergy efficiency. Conventional energy analysis is performed based on the First Law of Thermodynamics. Unlike from the First Law, the Second Law or exergy analysis (defined as useful work) has appeared in the literature, while this analysis not only assesses quantity but also quality of energy. In this study, exergy analysis of a milk powder production system, mainly includes 3 processes (pasteurization, evaporation and spray drying) which will be presented. The aim of the study is to apply a thermodynamic analysis including comprehensive exergy analysis by using different performance parameters such as exergy efficiency, improvement potential rate, sustainability index, relative irreversibility and exergetic factor for the milk powder production system. As a result, exergetic efficiencies of the system components were found in the range of 9-83%. The overall energy and exergy efficiencies of the whole milk powder production system were calculated as 85.4 and 57.45%, respectively. Additionally, it was found that the evaporator and the heater have a higher impact in improvement actions.