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.