Continuous biodiesel production using a fixed-bed Lewis-based catalytic system

It was developed a fixed bed tubular continuous reactor to produce biodiesel, using pellets of aluminum oxide doped with zinc oxide. The pellets were placed into a tubular reactor as a 30 cm long column (2.65 kg). The reactor was feed with soybean oil (168 g h(-1)) and methanol or ethanol (89 g h(-1)) with the temperature fixed at 100 degrees C. Under these conditions it was possible to convert soybean oil into biodiesel in up to 75% yield in the case of methanol and 35% for ethanol. Increasing the temperature to 180 degrees C, it was possible to ethanolise soybean oil with yields up to 78%. It is important to note that after a steady state is achieved the conversions remained approximately constant with time. It is also worth to mention that the fixed bed remained active for more than 120 h, showing no catalyst leaching or deactivation, and so far it was not possible to determine its overall productivity. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.