Production of fatty acid ethyl esters from rubber seed oil in hydrodynamic cavitation reactor: Study of reaction parameters and some fuel properties

The attributes of environmental balance, lower exhaust emission and renewability have made ethylic biodiesel production a preferable technique to methylic biodiesel production from inedible lipid oil. Hydrodynamic cavitation reactor (HCR), in particular has engaged a global interest due to its flexibility and desirable biodiesel properties. For the first time, the study adopted HCR to produce ethyl esters (biodiesel) from low FFA rubber seed oil (RSO). The effects of transesterification variables namely catalyst dosage (KOH) (3-5 wt.%), reaction time (30-50 min) and ethanol/RSO molar ratio (3.5 7.0) were examined on the biodiesel yield. The yield of rubber seed oil ethyl ester (RSOEE) (92.5%) was the highest at the ethanol/oil molar ratio of 6/1, KOH of 4.5 wt. and reaction time of 40 min. The cavitational yield for RSOEE production in the cavitation reactor was 4.13 g/J. The fuel properties of the RSO ethyl esters synthesized from the HCR were within the ranges of the ASTM D6751 and EN 14214 specifications. However, the oxidation stability (OS) did not comply with the standards. To further improve the low OS, the antioxidant can be included in the RSOEE to enhance the OS to an acceptable limit (> 6 h). Therefore, the HCR can be a feasible reactor for the production of cleaner and renewable fuel from various feedstocks.