Study of an energy-integrated biodiesel production process using supercritical methanol and a low-cost feedstock

D.L.MANUALE; G. TORRES; C. VERA; J.C YORI

FUEL PROCESSING TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 140 p. 252 - 261

0378-3820

The supercritical biodiesel production process has some disadvantagessuch as: high reaction temperature, large molar methanol-to-oil ratios (R) andlarge energy consumption. To mitigate these problems, an energy integratedprocess in which biodiesel is obtained in a continuous tubular reactor operatingat a reaction temperature of 280 ºC, R=20, a residence time of 1 h and apressure of 110 bar, is proposed. A low-cost lipid feedstock (chicken oil) wasused as raw material for testing the process. The enthalpy content of thestream exiting the supercritical reactor was used to eliminate the unreactedmethanol in an adiabatic flash drum. The operating conditions of the adiabaticflash were optimized to meet the specification of water and methanol content inthe biodiesel phase and minimize the ester and acid content in the vapourphase. These conditions were: P=0.1 bar and T=178 ºC. For these conditionsthe methanol content is 88-90% in the vapor phase and lower than 0.2% in thebiodiesel phase. A scheme was developed for an energy integrated processmaximizing the heat recovery. Composition, temperature and pressure of thestreams were determined and also the amount of heat exchanged in each unit.In order to fulfill the quality restrictions the final content of FFA in the biodieselproduct had to be further adjusted by adsorption over bleaching silica.