响应面法优化钙基固体碱KF/CaO 催化沉香籽油制备生物柴油

采用固体碱KF/CaO催化沉香籽油进行酯交换反应制备生物柴油(脂肪酸甲酯),通过扫描电镜、X射线衍射和傅里叶红外的表征发现KF/CaO呈多层片状结构,具有较大的比表面积(107±0.5)m2/g,催化活性主要成分为KCaF3,红外谱图验证了Ca―O―F晶格的存在。单因素试验对影响催化酯交换反应的各因素进行优化,得出较佳范围为:反应时间100 min、催化剂用量2.0%、醇油摩尔比8:1、反应温度79 ℃。单因素试验基础上采用Design-Expert软件Box-Behnken模块进行响应面试验条件优化,探讨了催化剂用量(A)、反应温度(B)、醇油摩尔比(C)、反应时间(D)4个因素及各因素间交互作用对转化率的影响,结果表明各因素一次项对转化率都呈高度显著水平,最佳条件为:反应时间107.2 min、催化剂用量2.02%、醇油摩尔比8.36:1、反应温度79.14 ℃,所制备的生物柴油能够满足国标要求。
Aquilaria sinensis seed contains rich oil, and is one of the important raw materials of biomass energy. In the context of China's energy shortage, A. sinensis seed has an important significance. Fatty acid compositions of A. sinensis seed oil are mainly oleic acid, palmitic acid and palmitoleic acid. Solid base KF/CaO was used to catalyze transesterification to prepare traditional biodiesel(fatty acid methyl ester). The SEM, XRD and FTIR analyses showed that the catalyst KF/CaO had a structure of multilayer chip with a large specific surface area of(107±0.5)m2/g. The catalytic component on the surface of the catalyst was mainly KCaF3, and the existence of Ca―O―F lattice was verified by the Fourier transformed infrared spectrum(FTIR). Single factor experiment was used to optimize the factors affecting the transesterification reaction of A. sinensis seed oil, and the optimum transesterification reaction was obtained when the reaction time was 100 min; dosage of the catalyst(KF/CaO)was 2.0%; molar ratio of methanol to A. sinensis seed oil was 8:1; and the reaction temperature was 79 ℃. The response surface experiment was then optimized by using the Box-Behnken module of the Design-Expert software. The influence of catalyst dosage(A), reaction temperature(B), the molar ratio of methanol to oil(C), reaction time(D)and the interaction between these factors on the conversion rate was investigated. The results showed that the influence of all the factors was highly significant. The optimum parameters of the catalytic transesterification reaction of A. sinensis seed oil was: time of the reaction was 107.2 min; dosage of the catalyst(KF/CaO)was 2.02%; molar ratio of methanol to A. sinensis seed oil was 8.36:1; temperature of the reaction was 79.14 ℃. The prepared bio-diesel can meet the requirements of the national standard