A sustainable and cost-efficient approach for recovering organic acids from biomass fermentation broths is nanofiltration membrane separation. This technique offers a viable alternative to traditional separation methods by reducing energy consumption and operational costs while maintaining high selectivity. To minimize reliance on costly and time-intensive experimental methods, rigorous thermodynamic modeling is essential.
This work presents a comprehensive thermodynamic modeling framework in ASPEN Plus to predict the separation behavior of commercially available nanofiltration membranes for multicomponent aqueous organic acid systems. The model extends the classical solution-diffusion approach by integrating detailed aqueous phase chemistry, non-ideal solution behavior, and membrane-solution interactions. By incorporating these factors, the framework enables accurate predictions of organic acid transport, rejection, and selectivity under a wide range of operating conditions.
Simulations in ASPEN Plus effectively describe the separation performance of a bench scale nanofiltration membrane NF-90 recently reported for single, binary, and ternary aqueous organic acid systems of acetic acid, butyric acid, and lactic acid, covering key parameters such as feed pH (3–10), acid concentrations (0.2–0.6 mmol/L), and applied pressures (3.44–27.57 bar) at 298.15 K.1 This model provides key insights for subsequent modeling and simulation of pilot scale and industrial scale nanofiltration processes, enhancing efficiency and economic viability.
1 N. Anjum, H. Wu, A. Lomax, L. Valentino, M. Urgun-Demirtas, C-C Chen, “Experimental investigation of nanofiltration separation performance for aqueous organic acid solutions,” (in preparation)