Biodiesel by - product glycerol used as extractant for removing the alkaline catalyst KOH in crude biodiesel was proposed. The solubilities of KOH in the glycerol and refined biodiesel were measured at different temperatures. Meantime, the effects of amout of KOH, methanol and feedstock type on the distribution coefficient of KOH in the glycerol and biodiesel system were investigated. The results showed that KOH was soluble in the glycerol, but was slightly soluble in the refined biodiesel. With the increase of KOH content, the distribution coefficient of KOH in the glycerol and biodiesel system decreased. The presence of methanol reduced the distribution coefficient of KOH in the glycerol and refined biodiesel system. Impurities in the feedstock played the key role on the distribution coefficient of KOH, and the more the impurity including soap and colloid in the crude biodiesel was, the less the distribution coefficient of KOH was.%提出了以生物柴油副产物甘油为萃取剂脱除粗生物柴油中碱催化剂KOH的新工艺.测定了不同温度条件下KOH在甘油和精制生物柴油中的溶解度,考察了KOH用量、甲醇和原料油种类对KOH在甘油/生物柴油体系中的分配系数的影响.结果表明:KOH在甘油中属于易溶,而在精制生物柴油中属于微溶,甘油可作为KOH的优良萃取剂；随着碱催化剂KOH用量的增大,KOH在甘油/生物柴油体系中的分配系数逐渐减小；甲醇的存在,减小了KOH在甘油/生物柴油体系中的分配系数；原料油中的杂质成分对KOH在甘油/生物柴油体系中的分配系数影响较大,制备的粗生物柴油中皂化物、胶质越多,分配系数越小.
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