Dynamic modeling of fouling over multiple biofuel production cycles in a membrane reactor

In this paper, a novel mathematical model that combines a membrane filtration model, component balances and reaction kinetics models for an intensified separation-reaction process in membrane reactor producing biofuels was developed. A unique feature is that the proposed model can capture the dynamics of membrane fouling as function of both reversible and irreversible fouling; which leads to cyclic behavior. Fouling leads to the decline of the reactor productivity. With an appropriate fouling-model, the operational strategy can be optimized. In the case study of biodiesel production, the developed model was validated with experimental data. The model was in good agreement with the data, where R-squared are 0.96 for the permeate flux and 0.95 for the biodiesel yield. From a further analysis, the efficiency of membrane reaction system in term of productivity can be significantly improved by changing the backwashing frequency under specific operating conditions. As the backwashing frequency increased eight times, the biodiesel yield increased to more than two to three times before the permeate flux dropped under a predetermined limit due to the increase of irreversible membrane fouling.