两步法利用高酸值潲水油制备生物柴油研究

摘要

A two-step catalyzed process was developed to prepare biodiesel from waste cooking oil (WCO) in this study.Free fatty acid of WCO was esterified with methanol catalyzed by polyferric sulfate in the first step, and then triglyceride of WCO was transesterified with methanol catalyzed by potassium hydroxide.Results showed that polyferric sulfate had strong activity to catalyze the esterification.The optimal parameters of esterification obtained by response surface as follows :5.87 ％ ( of the WCO mass) of polyferric sulfate, 108.7％ (of the WCO mass) of methanol,6.0 h of reaction time and 80 ℃ of reaction temperature.Under this condition, the AV reached as low as 2.20 mgKOH/g,and the esterification rate was 97.71％.The yield of purified biodiesel was 98.20％ from the crude biodiesel obtained by this two-step process by molecular distillation at 110 ℃.Composition of fatty acid methyl ester of the purified biodiesel was analyzed by gas chromatography (GC).Some physical and chemical properties of purified biodiesel were detected according to national standards for biodiesel.%以潲水油为原料,采用两步催化法制备生物柴油.先用聚合硫酸铁催化潲水油中游离脂肪酸和甲醇酯转化为脂肪酸甲酯,然后再通过碱催化剩余的甘油三酯进行酯交换反应.通过响应面试验设计优化酯化反应,结果表明,在反应时间6.0 h、甲醇用量108.7%(质量比,按油质量)、催化剂用量5.87%(质量比,按油质量)、反应温度80℃下,酸值可达到2.20 mgKOH/g,即酯化率为97.71%.在¨0℃下对经两步催化得到的生物柴油进行分子蒸馏,得率为98.20%,测定了生物柴油的脂肪酸甲酯组成,按照国标检测了纯化的生物柴油的物化性质.