Energy and exergy analyses of the spray drying process of fish oil microencapsulation

An energy and exergy analysis was carried out on the process of fish oil microencapsulation using spray drying. The process was carried out on a mini-spray dryer conducted at three drying air temperatures of 140, 160, and 180 °C. Various milk-originated single, and composite wall materials including skim milk powder (SMP), whey protein concentrate (WPC), whey protein isolate (WPI), 80% WPI + 20% milk protein concentrate (MPC), and 80% WPI + 20% sodium caseinate (NaCas) were used in the formulation of emulsions. The effects of drying air temperature and wall material on the energy efficiency, energy loss from drying chamber, exergy efficiency, exergy destruction, entropy generation and improvement potential were investigated. The energy and exergy efficiency values for spray drying process of fish oil microencapsulation at the drying air temperature between 140 and 180 °C were found to be in the ranges of 7.48–8.54% and 5.25–7.42%, respectively. The results of this study also confirmed that the exergy analysis using second law of thermodynamics is a potential tool for optimising dryer operation and design.

► Low energy and exergy efficiency in spray drying for fish oil microencapsulation. ► Significant effects of drying air temperature on energy and exergy efficiency. ► Decreasing energy and exergy efficiency with increasing in inlet drying air temperature. ► Smaller exergy efficiency compared with energy efficiency.