Intensification of biodiesel production using dual-frequency counter-current pulsed ultrasound

Ultrason Sonochem. 2017 Jul:37:136-143. doi: 10.1016/j.ultsonch.2016.12.036. Epub 2016 Dec 30.

Abstract

Biodiesel production from soybean oil deodorizer distillate intensified by dual-frequency counter-current pulsed ultrasound and the kinetics were studied. Results indicated that the biodiesel conversions enhanced by single-frequency were lower than those enhanced by dual-frequency. For dual-frequency, the biodiesel conversion of SMM was higher than those of SQM. The biodiesel conversion of the combination of 20/28kHz is the highest. The effects of 20/28kHz SMM on biodiesel production were studied and optimal conditions were: methanol to triglyceride molar ratio 8:1, catalyst content 1.8%, the water content in feedstock should be less than 0.4%, the acid value of feedstock should be less than 2mgKOH·g-1, the biodiesel conversion could reach 96.3%. The kinetics of SMM and SSPU were studied and results showed that the transesterification reaction was pseudo-second order and the energy activation obtained by SMM and SSPU were 18.122kJ·mol-1 and 26.034kJ·mol-1, respectively. These results showed that transesterification reaction intensified by SMM is easier to take place than SSPU.

Keywords: Biodiesel; Dual-frequency counter-current pulsed ultrasound; Kinetic; Soybean oil deodorizer distillate.