Location: Dairy and Functional Foods ResearchTitle: Environmental assessment of alternative pasteurization technologies for fluid milk production using process simulation
Submitted to: Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/4/2015
Publication Date: N/A
Technical Abstract: Fluid milk processing (FMP) has significant environmental impact because of its high energy use. High temperature short time (HTST) pasteurization is the third most energy intensive operation comprising about 16% of total energy use, after clean-in-place operations and packaging. Nonthermal processes for production of shelf - stable or extended shelf-life milk need to be explored. The objective of this study was to develop alternative pasteurization models to be used in a computer simulator to estimate their impact on energy use and thus greenhouse gas (GHG) emissions. Only alternative processes that are currently amenable to continuous FMP were selected. Models were developed for pulsed electric fields (PEF), microfiltration (MF), and ultrahigh temperature (UHT) processing. The simulator was built using SuperPro Designer (Intelligen, Inc., Scotch Plains, NJ). A plant producing 113.6 M L/yr of milk and 40% cream and extending from raw milk storage to cold, processed milk storage was simulated. Results indicated that greenhouse gas emissions, reported as carbon footprint of milk, were lowest at 37.6 g C02 equivalents (e)/kg raw milk processed (RMP) for HTST pasteurization. GHG emissions for PEF were the highest of the alternative methods at 99.1 g C02e/kg RMP. Specific energy consumptions (SEC) for HTST milk were 0.14 MJ/kg RMP for electrical use and 0.13 MJ/kg RMP for natural gas use while SEC for PEF was 0.44 MJ/kg RMP and 0.10 MJ/kg RMP, respectively. Energy use for PEF was 51.7% of the total energy for FMP. Other scenarios using PEF in the FMP simulator should reduce the GHG emissions and SEC and will be explored. Operating costs associated with PEF were $0.52/L, $0.51/L for HTST and $0.60/L for UHT. Process simulation allows for determination of the performance of alternative technologies without costly pilot plant trials and is a useful tool to create process scenarios to improve the environmental impact of FMP.