超声波辅助制备米糠生物柴油及其燃料排放特性

Biodiesel production from rice bran oil by means of ultrasonic energy and emission properties as engine fuel

对超声波辅助碱催化米糠油与醇酯交换反应进行了一些列试验研究,并与传统机械搅拌法比较,论证其用于制备生物柴油的可行性。结果显示超声波辅助方法可以缩短酯交换反应的时间15～20min。超声频率40kHz条件下反应速度较28kHz快,但是由于产物水洗分离困难而使得产物得率反而有所下降。超声辅助酯交换法还可以减少催化剂的用量,当催化剂用量为质量分数0.5%时可得到最高的转化率和得率。轻型车排放试验结果显示燃用米糠生物柴油可以显著降低CO和HC排放,而NOx排放有少量增加。

Transesterification of rice bran oil with alcohol, in presence of base catalyst, was studied with low frequency ultrasound, as well as the discussion of the feasibility of biodiesel preparation with ultrasonic assistant. By using ultrasounds, the reaction time was reduced 15 -20 min compared to mechanical stirring. The reaction rate of the 40 kHz ultrasound was faster than that of 28 kHz but lower yield than 28 kHz ultrasound. The quantity of required catalyst can be reduced with ultrasonic assistant. The best yields were obtained when the catalyst was used in 0.5% wt/wt of oil. The differences in the product yield were mainly due to difficulties through washing. Emission tests have shown a marked decreasing in CO, HC, and PM with a slight increasing in NOx, however.