Modeling, simulation and optimization of integrated milk pasteurization and membrane filtration processes

This work presents a model-based, computer-aided framework for the modeling, simulation, and optimization of integrated pasteurization and membrane filtration processes of a dairy plant producing milk powder. One of the key objectives is to evaluate how key physicochemical and biological phenomena, such as protein denaturation, fouling, enzyme inactivation, and microbial growth, affect process operating conditions, product-quality constraints, cleaning requirements, and utility consumption. Two process models are developed in the gPROMS™ FormulatedProducts platform to compare the performance of separate pasteurization and membrane filtration sections with an integrated configuration. A Global System Analysis is applied to capture interactions among key process variables and to quantify performance variability under process uncertainty. Model-based optimization is then conducted for both the individual processes and the integrated system. The optimization results suggest a pasteurization temperature of 73 °C (High-Temperature Short-Time method), an increase in the regenerative unit heat transfer area and allocation of 100% of diafiltration water to the third membrane stage, leading to 30%, 100% and 49% reductions in heating, chilled and diafiltration water usage, respectively. Furthermore, optimization of the integrated process yields a 9.9% increase in profit, demonstrating the benefits of a holistic, system-level approach to dairy process design and optimization.