KOH/ZrO_2催化制备生物柴油新工艺

New technique of biodiesel preparation catalyzed by KOH/ZrO_2

采用浸渍法,将KOH负载在新型载体氧化锆上,通过高温煅烧得到了固体碱催化剂。探讨了制备条件对催化剂催化酯交换反应活性的影响,获得了催化剂的最佳制备条件,以大豆油和甲醇为原料研究并优化了催化酯交换反应制备生物柴油的工艺条件。结果表明,固体碱催化剂KOH/ZrO_2的最佳制备条件为:KOH负载量20%,煅烧温度600℃,煅烧时间2h。固体碱催化剂催化酯交换反应的最优反应条件为:醇油比9∶1,反应温度75℃,反应时间3h,催化剂用量4.0%。各因素对产率影响的大小为:醇油摩尔比>反应温度>反应时间>催化剂用量。

The solid base catalyst KOH/ZrO 2 was prepared by impregnation method,in which KOH was loaded onto a new support,ZrO 2 ,and followed by drying and high temperature calcinations.The catalyst was characterized by XRD, TGA-DSC and FT-IR respectively.The results show that KOH has been loaded on ZrO 2 successfully,which can be proved by the appearance of coordinated hydroxyls on the surface of ZrO 2.However, the crystal structure of KOH/ZrO 2 does not change significantly when compared with the structure of carrier.The preparation conditions for catalysts of different loading amount were determined via transesterification reaction.The optimal preparation conditions are as follows:loading amount of KOH 20%,calcination temperature 600℃,calcination time 2 h.The solid base catalyst KOH/ZrO 2 was applied in catalyzing the transesterification of soybean oil with methanol, and the maximum yield of biodiesel can be higher than 90%.The influence of the reaction variables on the conversion was also investigated,and the optimal reaction conditions are as follows:reaction temperature 75℃,oil/methanol molar ratio 9∶1,reaction time 3 h,catalyst dosage 4.0% (mass).