粉煤灰负载型催化剂的制备及其在生物柴油合成中的应用

Preparation and application of catalyst with fly ash as carrier in biodiesel production

【目的】制备NaOH/NaNO3/粉煤灰,并以其为非均相催化剂进行生物柴油酯交换反应,同时对影响固体碱催化剂催化活性的因素进行分析。【方法】采用4因素4水平正交试验,探讨NaOH含量、NaNO3含量、催化剂煅烧温度及时间对固体碱催化剂活性的影响,以获得固体碱催化剂的最佳制备条件;并用扫描电镜、红外光谱分析及X射线衍射对催化剂结构进行表征。【结果】固体碱催化剂的最佳制备条件为:NaOH含量200mg/g,NaNO3含量200mg/g,催化剂煅烧温度270℃,煅烧时间4h;催化剂可回收循环使用;结构表征结果显示,该催化剂具有碱性活性中心。【结论】将通过此条件制得的催化剂用于酯交换反应,在最佳反应条件下,棉籽油的转化率可达98.75%。

[Objective] A new heterogeneous solid base catalyst,composed of fly ash,NaOH and NaNO3,was prepared to produce biodiesel by transesterification.The factors of activity of solid base catalyst were analyzed.[Method] Through orthogonal analysis of parameters in a four-factor and four-level test,the reaction conditions for the preparation of catalyst such as the content of NaOH and NaNO3,the catalyst calcination temperature and time were performed.Orthogonal analysis can optimize the best preparation conditions for the highest activity of the catalyst.The catalyst was characterized by SEM,IR and XRD.[Result] The optimum conditions for catalyst preparation were obtained as follows：NaOH content of 200 mg/g,NaNO3 content of 200 mg/g,the catalyst calcination temperature of 270 ℃ and the calcination time of 4 h.The result of characterization showed that the catalyst had alkaline active site.[Conclusion] The base catalyst exhibits excellent catalytic activity for the transesterification between cottonseed oil and methanol,and the conversion of reaction reaches 98.75% under the optimum conditions.