CONICET | Buscador de Institutos y Recursos Humanos

The supercritical biodiesel production has some disadvantages such as: high reaction temperature, large molar ratio of methanol/oil (R) and large energy consumption. To solve these problems, an energy integrated process where biodiesel is obtained in a continuous tubular reactor operating at a reaction temperature of 280 ºC, R=20, residence time of 1h and a pressure of 110 bar, was proposed. The enthalpy content of the stream exiting the supercritical reactor can be used to eliminate the unreacted methanol in an adiabatic flash drum. The operating conditions of the adiabatic flash were optimized to meet the specification of water and methanol content in the biodiesel phase and minimized the ester and acid content in the vapour phase. The same were: P=0.1 bar and T=178 ºC. For these conditions methanol content in the vapor phase is 88-90% and lower to 0.2% in the biodiesel. A scheme was developed for a heat integrated process optimizing the heat recovery. Composition, temperature and pressure of the streams 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 biodiesel product must be further adjusted.