| Popis: |
The innocuous utilization of diseased swine carcasses is a key issue in reducing environmental pollution and ensuring safety in animal husbandry. In this study, by using fat from diseased swine carcasses as raw materials, response surface experiments were conducted to investigate the influences of reaction time, catalyst concentration, reaction temperature, and methanol/oil molar ratio on the biodiesel purity and the optimum conditions for biodiesel production were determined. Furthermore, three-dimensional (3D) ultrasound assistance was adopted and kinetic analysis was performed. The results show that the influencing factors on biodiesel purity, in descending order, were determined to be reaction temperature > catalyst concentration > reaction time > methanol/oil molar ratio. Moreover, the maximum biodiesel purity was 93.7% under the following optimal conditions: catalyst concentration of 5.0 wt%; reaction temperature of 68 °C; methanol/oil molar ratio of 10:1; reaction time of 37 h. When 3D ultrasound assistance was adopted, the maximum biodiesel purity of 98.1% was obtained for the reaction process of 8 h under the ultrasound power and frequency of 500 W and 20 kHz, respectively. And the esterification reaction time was significantly reduced, compared to without ultrasound assistance. The results of kinetic analysis demonstrate that the reaction rate constants of the ultrasound group were 4.45–5.52 times greater than that of the control group. And the activation energy for the ultrasound group was 25.58 kJ/mol, which is 22.81% lower than that of the control group. This study will help to conduct large-batch biodiesel production from diseased swine carcasses in the future. |
