Refining of crude glycerol produced from the production of Xanthoceras sorbifliaBunge seed oil biodiesel

The by-product of crude glycerol produced by transesterification of Xanthoceras sorbiflia Bunge seed oil biodiesel,contained soaps,methanol,water and esters,and the content of glycerol was 30%-60%.The crude glycerol was refined by saponification,acidification,polar solvent extraction and activated carbon adsorption.The results showed that the highest glycerol purity of 98.5% was obtained by saponification with KOH-CH3OH solution,acidification at pH 2.5 adjusted with H3PO4,extraction with volume ratio of methanol to crude glycerol 4∶ 1 and adsorption with activated carbon at 100 g/L.