The transesterification of rapeseed and waste sunflower oils: Mass-transfer and kinetics in a laboratory batch reactor and in an industrial-scale reactor/separator setup

Influence of Mass Transfer and Kinetics on Biodiesel Production Process

“…The high yield for the crude cottonseed oil biodiesel under the ultrasonic irradiation condition is also attributed to the efficacy of cavitation, which can enhance the mass transfer between the methanol and crude cottonseed oil (Fan et al, 2010). At three temperatures studied by Stamenkovic et al (2008), the mass transfer coefficients of triglycerides into alcohol phase (at good confidence interval values) ranged from 1.40 (± 0.01) × 10 −7 to 1.45 (± 0.01) × 10 −6 m s −1 , consistent with the reported literature values of approximately 10 −7 −10 −3 m s −1 (Frascari et al, 2009;Klofutar et al, 2010). From these values, the specific activation energies of first-order triglyceride mass transfer (E a ) were estimated, and again a good fit was obtained.…”

“…Table 2 shows the calculated effective activation energies and pre-exponential factors of mass transfer coefficients (E a and k c0 ) for different reaction conditions and the corresponding literature sources. Similar activation energy values were obtained for the methanolysis of sunflower oil regardless of different impeller speeds (Stamenkovic et al, 2008;Klofutar et al, 2010). The disagreement was quite small in both cases, and as a result, the proposed mass transfer model adequately described the results from the experiments.…”

“…The estimated mass transfer coefficients for sunflower oil and KOH catalyst reported in the literature (Frascari et al, 2009;Klofutar et al, 2010) were compared at similar mixing rates. Lower mass transfer coefficients were reported for lower temperatures, since the mass transfer coefficients obtained by Frascari et al (2009) at 60 °C were greater than that obtained by Klofutar et al (2010) at 40 °C and 50 °C. The mass transfer coefficient (k c a) determined by Ataya et al (2007) was much lower than that reported in the other literature.…”

“…The solution to the new system model acknowledging mass transfer and kinetics is presented in Fig. 2 Klofutar et al (2010). The value of each parameter of Equations (2)− (7) is given in Table 3.…”

Monitoring of Biodiesel Transesterification Process Using Impedance Measurement

“…For the transesterification of crude sunflower oil it was shown that the mass transfer limitation was reduced to an effective zero time lag by selecting a 400-600 rev/min agitation speed. Other researchers [12], [13] have revealed that mass transfer coefficients achieved for the transesterification process using mechanical agitation with the mixing rate of 700 min-1 is 10.3 times higher than that reported with 100 min-1 mixing rate. In addition the use of a higher reaction temperature can reduce mass transfer limitations with the higher energy level of molecules resulting faster diffusion into a pseudo homogeneous phase [14].…”