关键词: 粗甘油, 甲酸钠, 生物柴油, 提纯, 富甘油层

Abstract: Purification of original crude glycerol from by-product of biodiesel was conducted on a laboratory scale by using the combined chemical and physical treatments based upon repeated cycles of acidification to the desired pH of 5 using 85％ H3 PO4 at 70℃ for 60 min, allowing phase separation and harvesting of the glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, the complex reaction of the harvested glycerol phase occurred by adding 0.03 %( w/w) of sodium oxalate at 80℃ for 30min with the impurity removal rate of 19.8%. The fraction between 164 and 200℃ was collected by vacuum distillation followed by decolorization with 2% of active carbon at 80℃ twice at an acceptable purity of 98.10% (w/w) glycerol.

Key words: Crude glycerol, Sodium oxalate, Biodiesel, Purification, Glycerol-rich layer