Ultrasonic Assisted Pressurized The Catalyzed Transesterification Biodiesel Production

Biodiesel, as the "green Energy sources", is considered a perfect substitutite of fossil diesel. As for its good combustibility, renewable resource, environmental friendly, biodiesel has become the focus for enterprises and researchers.As for the biodiesel by transesterification, ultrasonic stirring has a significant strengthening effect. It can not only do the mixing, which can greatly improve the heterogeneous-mass transmission and promote contacts between molecules, but also reduce the activation energy with cavitation. In order to overcome the shortcomings of traditional methods, transesterification on preparation of biodiesel with ultrasonic assistant under pressurization was proposed in this paper. The Jatropha curcasl oil was used as raw material and the experiment research was carried out to produce biodiesel in batch and continual pipeline under pressurization by transesterification with the ultrasonic assistant. And the thermal analysis was carried out for the prepared biodiesel. The conclusions are as following:(1)Experimental study was conducted to produce biodiesel in batch by transesterification with the ultrasonic assistant. And the reaction temperature, molar ratio of methanol to oil, the amount of catalysts, ultrasonic power and reaction time were investigated on the impact to the conversion. The conversion rate can reach 96.35% by following conditions:reaction temperature is 75℃, molar ratio of methanol to oil is 7:1, dosage of KOH is 1%(W/V), ultrasonic power is 150W and reaction time is 150 min. The kinetics calculation indicates that the relationship between reaction order and temperature is n=f (T)=6 X 10-6T4-0.0083T3+3.9595T2-846.46T+6.7788 and activation energy is 42.85kJ-mol-1 respectively, and frequency factor is 3.1 X 108. Kinetic modeling(2)Experimental study was conducted to produce biodiesel by transesterification with the ultrasonic assistant on continual preparation and pressurization. And molar ratio of methanol to oil, the amount of catalysts, ultrasonic power, material velocity and reaction temperature were investigated on the impact to the conversion. The conversion rate was 97.01% by following conditions:feed pressure is 0.3MPa, reaction temperature is 45℃, molar ratio of methanol to oil is 6.5:1, dosage of KOH is 1.7%(W/W), ultrasonic power is 180W and material velocity is 3.3mL/min.(3)The thermal analysis result of biodiesel made from jatropha curcasl oil shows that the combustion process can be broadly separated into three stages:low weightless, fast weightless, and combustion of fixed carbon.The kinetics calculation indicates that the activation energy in three stages were separately 563J/mol,4400J/mol and 1170J/mol under the heating rate of 20℃/min. It also means that the activation energy is largest in the fast weightless stage and the heating rate has no much infection on the activation energy.