固体催化剂在麻疯籽油生物柴油制备中的应用

发布时间：2018-04-25 14:44

  本文选题：麻疯籽油 + 固体催化剂　； 参考：《江南大学》2015年硕士论文

【摘要】：生物柴油作为一种新型能源,具有清洁环保、可再生性强的特点,对解决石化能源短缺及环境污染等问题具有重要意义。目前,工业化的生物柴油主要是通过均相酸、碱催化酯交换法反应制备的。然而,与传统的均相催化法相比,固体酸、碱催化因具有反应后处理简单、对环境友好等特点,成为了当今社会的研究热点。本文通过共沉淀法和浸渍法制备固体酸、碱催化剂,以麻疯籽油为原料,系统地研究了固体催化剂在生物柴油制备中的应用。首先,采用共沉淀法和浸渍法制备固体酸、碱催化剂,优化制备条件,并进行表征。研究表明,固体酸Ti(SO4)2-Zr(SO4)2/Si O2及固体碱K2CO3/Mg O-Al2O3具有较高的催化活性。以Si O2为载体,当硫酸钛与硫酸锆的配比满足nT i:nZr=3:1,焙烧温度为300°C时,固体酸Ti(SO4)2-Zr(SO4)2/Si O2催化效果较好;当硝酸镁与硝酸铝盐溶液的配比满足nMg:nAl=3:1,碳酸钾负载量为25%,焙烧温度为550°C时,固体碱K2CO3/Mg O-Al2O3的催化效果较好。固体酸的表征结果表明,硫酸锆和硫酸钛以Si-O-Ti键和Si-O-Zr键的形式负载到Si O2载体表面,形成复合型催化剂;固体酸微粒呈规则圆球形,大小均匀,粒径为200~400 nm;固体碱的表征结果表明,焙烧后形成的复合氧化物Mg(Al)-O-K及K2O是提高催化剂活性的原因;固体碱微粒为层片状,大小为200~500 nm。其次,以麻疯籽油为原料,研究固体催化剂在生物柴油制备中的应用。研究表明,固体酸-碱两步催化法适用于催化麻疯籽油制备生物柴油,其中,固体酸催化预酯化反应的最优工艺为:催化剂用量2.0%,醇油摩尔比12:1,温度75°C,时间2 h,酸值可由10 mg KOH/g降为0.78 mg KOH/g,酯化率达92.73%;在预酯化反应的基础上,固体碱催化酯交换反应的最优工艺为:催化剂用量2.0%,醇油摩尔比12:1,温度65°C,时间2 h,转化率为95.98%。最后,以固体酸催化预酯化反应产物为原料,研究固体碱催化酯交换反应动力学,测定其反应产物的主要性能指标。结果表明,在温度为60°C、65°C及70°C时,固体碱催化酯交换反应的速率方程分别为:-rA=0.01512C0.7094,-rA=0.01785C0.7138,-rA=0.02194C0.8253;反应的活化能为35.35 KJ/mol。反应产物的测定结果表明,经固体酸-碱两步法催化后,麻疯籽油可转化为生物柴油,并且生物柴油性能良好,符合我国现行生物柴油标准(GB/T 20828-2014)。
[Abstract]:As a new type of energy, biodiesel has the characteristics of clean and environmental protection, strong reproducibility, which is of great significance to solve the problems of petrochemical energy shortage and environmental pollution. At present, industrial biodiesel is mainly prepared by homogeneous acid and alkali-catalyzed transesterification. However, compared with the traditional homogeneous catalytic method, solid acid and alkali catalysis has become the focus of research because of its advantages of simple post-treatment and friendly to the environment. In this paper, solid acid and alkali catalysts were prepared by coprecipitation and impregnation. The application of solid catalysts in the preparation of biodiesel was systematically studied using leprosy seed oil as raw material. First, solid acid and alkali catalysts were prepared by co-precipitation method and impregnation method, and the preparation conditions were optimized and characterized. The results show that solid acid Ti(SO4)2-Zr(SO4)2/Si O 2 and solid base K2CO3/Mg O-Al2O3 have high catalytic activity. When the ratio of titanium sulfate and zirconium sulfate to zirconium sulfate is 3: 1 and the calcination temperature is 300 掳C, the catalytic effect of solid acid Ti(SO4)2-Zr(SO4)2/Si O 2 is better, when the ratio of magnesium nitrate and aluminum nitrate solution meets nmg: n AlN 3: 1, the loading amount of potassium carbonate is 25 鈩，

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