Fast biodiesel production from beef tallow with radio frequency heating

Efficient biodiesel production from beef tallow was achieved with radio frequency (RF) heating. A conversion rate of 96.3 ± 0.5% was obtained with a NaOH concentration of 0.6% (based on tallow), an RF heating for 5 min, and a methanol/tallow molar ratio of 9:1. Response surface methodology was employed to evaluate the influence of NaOH dose, RF heating time, and methanol/tallow ratio. The alkaline concentration showed the largest positive impact on the conversion rate. Similar fast conversion from canola oil to biodiesel was achieved in our previous work, indicating that RF heating, as an accelerating technique for biodiesel production, had a large applying area. Viscosities of biodiesel products from beef tallow and canola oil were measured as 5.23 ± 0.01 and 4.86 ± 0.01 mm2 s−1, respectively, both meeting the specification in ASTM D6751 (1.9–6.0 mm2 s−1).