中文摘要：

通过比较传统溶液萃取脱酸和碱炼在地沟油脱酸过程中的效果,最终确定用萃取—碱炼联合法分离地沟油中的游离脂肪酸,以达到降低其酸值的目的.实验结果表明,最佳的工艺条件为：以乙醇为萃取剂,原料油与乙醇的比为1∶2.5（W/W）,萃取次数为2次,萃取时间为每次10 min,萃取温度30℃的条件下可将原料地沟油的酸值从10 mg KOH/g左右降至2 mg KOH/g以下;再利用碱炼法进行进一步的脱酸.利用该工艺,可以将地沟油的酸值降低至0.5 mg KOH/g以下,基本上可以达到后续生物柴油生产工序对原料油油品的要求,且所得油品质量较好,溶剂和皂脚均可回收利用,实现资源的最大化利用.

英文摘要：

In order to reduce the acid value of waste oil, the deacidification effect of traditional solvent extraction and alkali refining were compared, and the combination method of extraction-alkali refining was used to separate the free fatty acids from waste oil. The optimal conditions are： ethanol as the extraction agent; the proportion of ethanol and waste oil is 2.5：1; extraction twice; extraction time 10 min; extraction temperature 30 ~C. The result shows that the free fatty acids in waste oil can be reduced from 10 mgKOH/g to 2 mgKOH/g or less. After that, the method of alkali refining is used to reduce the acid value to 0.5 mgKOH/og,or less, which meets the demands of biodiesel production and biodiesel with better quality can be obtained. With this technology, the solvents and soapstock can be recycled to maximize the use of resources.