(637e) Evaluation of the Production of Biodiesel Using a Liquid-Liquid Film Reactor Packed with Hollow Fiber Membranes

Conventional processes for biodiesel production have showed limitations in the reaction and separation - purification stages. Stirring mechanisms are necessary due to limitations of mass transfer between oil and alcoholic phases, and chemical equilibrium makes obligatory two or three reaction – separation stages for achieve higher conversion and yield. The catalyzer, soaps formed and glycerol must be removed, using large amount of water, and generate wastes that must be treated before final disposed. These limitations have prompted the study of intensified processes for biodiesel production. The main focuses of these technologies are the optimization of the reaction stage, and increasing the performance of the separation – purification stages, with less use of energy. Among the technologies assessed, uses of membranes have been widely investigated. Membranes technologies have been evaluated for separation and purification of the product, mainly to remove free and bonded glycerol, as well as media for simultaneous reaction and separation and support for heterogeneous catalysts.

This study presents some results of the experimental evaluation of a continuous process for biodiesel production in a falling film reactor (FFR) using a semi-structured packing which includes stainless steel wires and polyethersulfone (PES) hollow fiber membranes (HFM). In these reactor the mass transfer area is created in a different, non-dispersive way through the use of a FFR, and the glycerol separation occur simultaneously, using hollow fiber membranes. This reaction – separation technique shift the reaction equilibrium to the product side, increasing conversion of oil and yield to methyl esters compared to reactor packed only with stainless steel wires. A bench-scale (5 kg/h production capacity) FFR was designed, constructed and tested. Permeate flux of each component individually and in the reactant mixture were determined inside the FFR using the semi-structured packing, at the temperature of reaction. Results showed that the semi-structured packing including PES-HFM is suitable to perform the simultaneous reaction and separation, with good selectivity to methanol – glycerol mixture permeation. The evaluation of the reaction in the FFR using the semi-structured packing including PES-HFM showed an increment on biodiesel yield in comparison to the FFR without membranes, although molar ratio methanol to oil increases in order to compensate the methanol that permeates through the membrane mixed with glycerol.