(744d) Modeling and Simulation of Membrane Reactor for Biodiesel Production

Biodiesel is an important renewable fuel whose production has been limited mainly by high residence times in the reaction and separation sections due to the presence of soaps and high viscosity gels. This work studies the possibility of reducing this problem by implementing a falling film reactor integrated whit hollow fiber membranes. This reactor takes advantage of both systems: while production of biodiesel using a falling film reactor is characterized by high reaction rates and productivity and a positive effect on separation stages because interfacial mass transfer area is achieved without mixing, the integration of a membrane system allows it increase the yield to fatty acid methyl esters as well as the simultaneous purification of the biodiesel obtained. In this work a mathematical model to predict the behavior of falling film reactor assisted by membranes was developed. The model describes a PFR reactor and the flux through the membrane by the transport equations of UF. A sensitivity analysis was performed to understand the operation of the membrane reactor and identify the main variables of the system. The model predicts the appropriate operating conditions range for experimental evaluation. Simulation of the process allows us to conclude that there is a strong drag effect exerted by methanol on the glycerol and that the conversion and yield in the reactor increase when the biodiesel and glycerol flux through the membrane rise, but they decreases when the flux of methanol increases, indicating that the amount of methanol fed to the reaction system is a main operating variable because it has strong influence on the transport through the membrane.