生物柴油副产物甘油精制工艺研究

Purification of glycerol from the by-product of biodiesel

以棕榈油为原料,碱法催化甲醇与棕榈油进行酯交换反应生成脂肪酸甲酯(即生物柴油)和副产物甘油。副产物粗甘油经过磷酸中和得到甘油半成品,再经过乙醇结晶、分子蒸馏得到高纯度甘油产品。通过正交实验得到乙醇结晶的最佳条件为:结晶温度20℃,结晶时间20 min,乙醇添加量为1∶1(V/W)。乙醇结晶后的甘油在温度110℃,压力30 Pa下进行分子蒸馏,得到纯度为99.5%的高纯度甘油。

The fatty acid methyl ester （biodiesel） and its by-product of crude glycerol were obtained by transesterification of palm oil with methanol catalyzed by potassium hydroxide. The semi-product of glycerol was prepared by neutralization with phosphorus acid, and then the semi-product was treated by ethanol crystallization and molecular distillation to obtain the finished glycerol with high purity. The optimal parameters of crystallization obtained by orthogonal experiment were as follows：crystallization temper- ature 20℃, crystallization time 20 min, and ratio of ethanol to semi-product of glycerol of 1 ： 1 （V/W）. The conditions of molecular distillation were temperature 110℃ and pressure 30 Pa. The purity of final product reached 99. 5%.