超临界甲醇法制备生物柴油

Production of biodiesel using supercritical methanol technology

研究了超临界甲醇法制备生物柴油中温度、醇油摩尔比、反应时间和助溶剂对甲酯生成率的影响,同时研究了加入少量的KOH以降低反应的苛刻条件。在超临界甲醇反应温度350℃,醇油摩尔比为42∶1的优化反应条件下,10 min后脂肪酸甲酯的产率达到95.0%以上;300℃时加入CO2和正己烷可以提高甲基酯的转化率;在160℃的亚临界状态下、醇油摩尔比为24∶1时,加入质量分数为0.1%的KOH,20 min后脂肪酸甲酯的转化率也达到了98.5%以上。

The effect factors of different reaction conditions on the yield of fatty acid methyl esters were investigated,which including reaction temperature,the molar ratio of methanol to oil,reaction time and co-solvent,etc.The rigorous operation conditions can be improved by adding a little amount of KOH.Under the optimal reaction conditions such as temperature of 350℃ and the molar ratio of methanol to oil of 42,a 95.0% yield of methyl esters was obtained in 10 minutes with the supercritical condition.With CO_2 or n-hexane as co-solvents in the reaction system,there was a significant increase in the methyl esters yield.Under the optimal reaction temperature of 160℃,the molar ratio of methanol to oil of 24,a 98.5% yield of methyl esters was observed in 20 minutes under the sub-critical condition with the 0.1 wt% KOH added.