Conclusions
In this study, a mathematical model is proposed to simulate the filtration performance of an EMR system for oligodextran production. The model was validated by a series of bench-scale experiments. Our modeling study evaluates the influence of selected membrane properties and operating conditions on EMR performance. The simulations demonstrate that uniform membrane pore size distribution and larger membrane porosity can significantly improve filtration efficiency and the quality of products;. Furthermore, although higher permeate flux may decrease energy consumption, it also reduces permeate concentration possibly due to a denser fouling layer, shorter retention time for hydrolysis, and more water convection transport (dilution effect). Different feeding modes resuls in different mechanisms of solute transport and thus affect the choice of operating pressure and agitation speed. Under the water feeding mode a more favorable performance can be obtained by applying a greater driving force together with a lower agitation speed to reduce fouling tendency. In contrast, the major challenge of the substrate feeding mode is more severe membrane fouling, therefore intense agitation together with medium operating pressure is beneficial for enhancing production efficiency. Our study theoretically highlights the technical feasibility as well as the practical constraints of an EMR system while providing important insights for its further development. Additional investigations can be performed on the pilot-scale EMR system operating in continuous mode. Other studies may be also required to explore EMR performance using various membrane module configurations (e.g. hollow fiber membrane modules, dynamic filtration modules with rotating or vibrating membranes etc.) to optimize system operation.