制备生物柴油的副产物甘油分离与精制工艺的研究

Study on the Recovery and Refining Technology of Glycerol from the By-product of Transesterification of Rapeseed Oil with Methanol

研究了菜籽油与甲醇酯交换反应的副产物甘油的分离与精制工艺,以及酯交换反应条件对甘油分离工艺的影响。研究表明:生成物静止分层后,反应下层液可采用甲醇为稀释剂(加入量为其质量的16 7%),中和后的pH值以5 0～6 0为宜,在离心温度≮20℃,离心机转速≥2000r/min,离心时间为7 5～10min时,分离得到的粗甘油经减压蒸馏,取164～204℃馏分,其甘油纯度大于98%,甘油的总收率为78%。

In this paper,the recovery and refining technology of glycerol from the by-product of transesterification of rapeseed oil with methanol was researched.The effect of the reaction conditions and the separation procedure on the yield of glycerol was discussed.After stopping of stirring react mixture,the crude product was separated into two layers.The bottom layer was first diluted with MeOH, whose usage amount of 16.7% based on the total amount of bottom layer,then was neutrialized to pH=5.0-6.0 by adding 46% H2SO4.Results showed that the yield of glycerol was high under these separation conditions:centrifugal temperature was ≮20℃,centrifugal rotation rate ≥2 000r/min,centrifugal time 7.5-10min.The total yield of glycerol was up to 78% based on the theoretical value and the glycerol purity in the end-product was 98%.