Biofuels production by esterification of oleic acid with ethanol using a membrane assisted reactor in vapour permeation configuration

[object ObjectBiodiesel production by performing the oleic acid esterification reaction in a new reactor system, realized by coupling the batch reactor with a tubular permeoselective membrane, has been investigated. Such reactor configuration was adopted to remove the water produced as by-product during the reaction thus increasing the oleic acid conversion and the alkyl ester production. The activity of acid catalysts and zeolites was evaluated in presence of methanol and ethanol. The membrane resulted much more selective towards water separation when ethanol was used, allowing to force thermodynamic equilibrium at higher conversion values. Very interesting results in terms of oleic acid conversion were achieved with both methanol and ethanol (96% and 98% respectively) in presence of a commercial Amberlyst-15 catalyst, at 80 °C, at a low membrane surface to gas volume ratio (0.20 cm-1) and low acid/alcohol molar ratio (2/1 and 1/1 respectively). Over zeolite samples, conversion values higher than 60% were obtained at 100 °C after 5 h in the esterification reaction performed in vapor permeation configuration.