Refinery 4.0: Biofuels from Vegetable Oils through HDO Process

This work has been devoted to evaluate the feasibility of bio-diesel production from crude tall oil through HDO process, shedding light on catalyst activity and selectivity as intrinsic factors in the design of refining process. The preliminary catalytic tests into HDO reactions of Crude Tall Oil (CTO) were carried out with a commercial catalyst, at 21bar of total pressure and varying the reaction temperature from 250°C to 300°C. Then, the consumption of H2 increases almost exponentially with the increase of the reaction temperature, reaching a maximum hydrogen conversion value of 16.5% at 300°C. This value corresponds to the 59% of the value of hydrogen theoretically needed for the complete removal of the oxygen contained in the reactant feed (i.e., the total oxygen in the CTO by CHNS-O is ca.12.0%). Accordingly, the biodiesel product yield (BPY) at 300°C (i.e., the mass of biodiesel formed per mass of CTO worked) results of 0.53 kgBioD_formed/kgCTO_feed, accounting for an oxygen removal grade of 57% on the basis of the theoretical limit of 0.93 BPY for the completed HDO.