Biodiesel Production With CERP/PVA Hybrid Catalytic Membrane

Biodiesel is a non-petroleum-based fuel that consists of alkyl esters derived from either the transesterification of triglycerides (TGs) or the esterification of free fatty acids (FFAs) with low molecular weight alcohols. Biodiesel made from renewable resources such as plant oils and animal fats is biodegradable and nontoxic. Another significant advantage of biodiesel is low emission profile, which does not contribute to global warming, so it is called the environment friendly biofuel. Therefore, research and development of biodiesel had caught the attention of the world.In this work, a hybrid catalytic membrane consisted of cation ion-exchange resin particles (CERP) and Poly (vinyl alcohol)(PVA) were prepared and used as heterogeneous catalyst for the esterification of acidified oil from waste cooking oil (WCO). The membranes annealed at different temperatures were charactered by SEM, FTIR, TGA and Ion exchange capacity (IEC). The FFAs conversion reached97.5%under the optimal conditions of methanol/acidified oil mass ratio2.5:1, catalytic membrane annealed at373K loading5g, reaction temperature337±0.5K, mechanical stirring480rpm and reaction time8h. The membrane annealed at373K exhibited the best catalytic activity and stability among the membranes, with FFAs conversion of85%at the sixth run. Also a pseudo-homogeneous kinetic model was established according to the experimental data. The reaction order was2.25and activation energy decreased from69.79to24.09KJ/mol with the increase of catalytic membrane loading from1g to7g in the experiment. The experimental data were consistent with the predicted results.Also another kind of hybrid catalytic membrane consisted of cation ion-exchange resin particles (CERP) and polyethersulfone were prepared and used as heterogeneous catalyst for the esterification of acidified oil with methanol to produce biodiesel. The membranes were characterized by SEM, FTIR, ion exchange capacity and swelling degree test. The membranes were annealed at different temperatures to improve catalytic activity and it is found that the membranes annealed at393K have the highest catalytic activity among the membranes. Orthogonal experiments were performed at four different conditions of reaction time, catalytic membrane loading, methanol/acidified oil mass ratio and reaction temperature, the results showed that the sequences of the four conditions are: reaction time> catalytic membrane loading> methanol/acidified oil mass ratio> reaction temperature. When esterification was performed with different alcohols, it is found that butanol has the highest FFAs conversion. Furthermore, pseudo-homogeneous kinetic models of the esterification of acidified oil with methanol, ethanol, propanol and butanol were established according to the experimental data, the results found that the model can well predict FFAs conversion.At last, CERP/PES membranes were used for the esterification of acidified oil with methanol under microwave irradiation. The main affecting parameters including reaction time, reaction temperature, catalytic membrane loading, methanol/acidified oil mass ratio and microwave power were analyzed to find out the optimal reaction conditions. The obtained results showed that reaction temperature, catalyst loading and methanol consumed in microwave assisted esterification (MAE) are slightly lower and the reaction time is much lower than that in traditional heating method (THE), which could lead to lower cost in biodiesel production. These results strongly demonstrated that the application of microwave condition could offer a fast, economical and easy route to produce biodiesel.