(800e) Biodiesel Production With a Membrane Reactor Over Heterogeneous Alkali Catalyst

Biodiesel, a mixture of fatty acid methyl ester(FAME), is a renewable and non-fossil fuel with less impact to the environment. However, the removal of residual oil from the product FAME is one of the mainly factors that plague biodiesel production costs, which largely limit its popularization and utilization. Membrane reactor could remove FAME from the system and simultaneously shifting the reaction balance to obtain relatively high oil conversion. Coupling heterogeneous alkali, a catalytic membrane reactor was applied to produce biodiesel from soybean oil, whose process combined the catalysis and separation in one step. Shaped KF/Ca-Mg-Al hydrotalcites catalyst was packed into the ceramic membrane tube. 30g soybean oil and 29.8g methanol (molar ratio around 1:24) were first mixed by strong stirring and heated to fixed temperature, and then charged into the preheated membrane reactor. Mixture of product FAME, glycerol and methanol was obtained from the permeate stream. And FAME could be obtained by layer separation after distilled excess methanol. The rest reactants as well as the distilled methanol were circulated. The central composite design experiments was applied to investigate the effects of reaction temperature, catalyst amount and circulation velocity on the biodiesel production. It was found that reaction temperature and catalyst amount had the positive effect on the FAME yielding rate while the circulation velocity had the negative effect on it. According to the experiment results, 70 °C, 0.531 g/cm³ of catalyst amount and 3.16 mL/min of circulation velocity was proved to be the optimum condition, which achieved a 0.1820 g/min FAME yielding rate within 150 min.