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

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, 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 and 26.034kJ·mol, respectively. These results showed that transesterification reaction intensified by SMM is easier to take place than SSPU.

Ultrasound-assisted transesterification of soybean oil using low power and high frequency and no external heating source

“…In a study by Fan et al [58] , by increasing the molar ratio from 3:1 to 6:1 utilizing a frequency of 40 kHz, the yield also increased. A similar study on the transesterification of soybean oil by ultrasound (20 kHz −28 kHz) reported an optimum reactant molar ratio of 8:1 [15] . Analyzing the obtained trends, one can say that the increase of yields of methyl esters due to excess methanol does not depend on the ultrasonic frequency (high or low) used in the measurement system.…”

“…The results show that both configurations, 1 MHz and 3 MHz, achieve higher conversion levels in a shorter period within higher molar ratios. It occurs due to methanol excess that shifts the reaction equilibrium towards FAME production and increases the number of cavitation bubbles due to greater ease of cavitation in methanol than in oil [15] , [57] . Than et al [22] have reported similar results with increasing molar ratio on transesterification of canola oil with methanol using low-frequency ultrasound (20 kHz).…”

Effects of flat sweep frequency and pulsed ultrasound on the activity, conformation and microstructure of mushroom polyphenol oxidase

“…Yin et al . [29] discovered that dual-frequency ultrasound would produce disturbance in mediums, addressing the drawbacks of single-frequency ultrasound’s unequal volume energy consumption and directional sensitivity. Kerboua et al .…”

Análise técnico-social da produção de biodiesel no Brasil e no desenvolvimento agrícola do norte de Minas Gerais

“…No entanto, a escolha acertada de um insumo adequado pode contribuir para reduzir esses impactos. O biodiesel é um biocombustível de baixo valor agregado e isso dificulta sua comercialização, por isso a utilização de óleos mais baratos e não comestíveis na sua produção em grande escala é uma alternativa (BACENETTI et al, 2017;YIN et al, 2017). A Tabela 1 apresenta as principais matérias-primas utilizadas para a produção de biodiesel no Brasil.…”