A novel spiral reactor for biodiesel production in supercritical ethanol

A spiral reactor is proposed as a novel reactor design for biodiesel production under supercritical conditions. Since the spiral reactor serves as a heat exchanger, it offers the advantage of reduced apparatus space compared to conventional supercritical equipment. Experimental investigations were carried out at reaction temperatures of 270-400 degrees C, pressure of 20 MPa, oil-to-ethanol molar ratio of 1:40, and reaction times of 3-30 min. An FAEE yield of 0.937 mol/mol was obtained in a short reaction time of 30 min at 350 degrees C and oil-to-ethanol molar ratio of 1:40 under a reactor pressure of 20 MPa. The spiral reactor was not only as effective as conventional reactor in terms of transesterification reactor but also was superior in terms of heat recovery. A second-order kinetic model describing the transesterification of canola oil in supercritical ethanol was proposed, and the reaction was observed to follow Arrhenius behavior. The corresponding reaction rate constants and the activation energies as well as pre-exponential factors were determined. (C) 2015 Elsevier Ltd. All rights reserved.