微管内催化制备生物柴油的工艺研究

发布时间：2018-08-28 13:30

【摘要】：随着化石能源的逐渐枯竭和环境污染的日益严重,生物柴油的研究逐渐成为热点。传统间歇反应制备生物柴油的过程生产强度远小于连续生产过程,且由于原料油脂与甲醇互溶性差,反应速率低、传质效果差等造成生产能耗过大。同时酸碱催化剂的处理需要大量水洗,难以回收。微管反应器比表面积大、传热传质性能好,可以保证物料分布均匀,维持反应体系温度恒定,在改善多相反应传质、强化反应过程以及提高安全性等方面有很好的工业应用前景。而离子液体具有绿色无污染、与生物柴油易分离、可循环使用等优点,被认为是21世纪最有希望的绿色溶剂和催化剂之一,在催化酯交换制备生物柴油领域具有广阔的应用前景。因此,进行微管内离子液体催化制备生物柴油的探索研究,将具有重要意义。本文首先对原料大豆油的理化性质进行分析,确定了原料中各成分的组成比例,核算出大豆油的相对分子量为870.31g·mol-1,基于气相色谱法确定了以十一酸甲酯为内标物的生物柴油定量分析方法；然后分别以传统酸碱催化剂和固体催化剂进行了间歇法催化制备生物柴油的反应研究,结果表明在合适的条件下,KOH催化产率可达到90.67%。然后采用PTFE材质微管作微反应器,T型微混合器用于大豆油和甲醇的混合,分别考察停留时间、反应温度、醇油摩尔比、催化剂用量四个单因素对酯交换反应的影响,并通过响应面法设计试验,利用Design-Expert对实验结果进行分析,考察各因素之间对生物柴油收率影响的交互作用。并确定了微管反应器内KOH催化酯交换的最优反应工艺：停留时间100s,反应温度58℃,醇油摩尔比9.70,催化剂用量1.57%,在此条件下转化率可达94.21%。基于以上间歇反应器和微管反应器中的最佳转化率进行工业放大设计计算,发现微管反应器在两种排布方式下,都可大大减小反应器总体积,实现高效快速生产,避免放大效应。最后本文进行了离子液体催化酯交换的实验,并探索了碱性双核离子液体[mim]2C4Im2在微管反应器内的催化效果。结果表明,该种离子液体微管内催化效果较差,需要进一步优化离子液体制备工艺,并选择合适的反应条件。
[Abstract]:With the depletion of fossil energy and the increasingly serious environmental pollution, the research of biodiesel has gradually become a hot spot. The production intensity of conventional batch reaction for biodiesel is much lower than that of continuous production, and the production energy consumption is too large due to poor solubility of raw oil and methanol, low reaction rate and poor mass transfer effect. At the same time, the treatment of acid-base catalyst needs a lot of water washing, so it is difficult to recover. The microtube reactor has large specific surface area and good heat and mass transfer performance, which can ensure the uniform distribution of materials, keep the temperature of reaction system constant, and improve mass transfer in multiphase reaction. It has a good prospect of industrial application in enhancing reaction process and improving safety. Ionic liquids are considered to be one of the most promising green solvents and catalysts in the 21st century because of their advantages such as green pollution, easy separation from biodiesel, recyclability and so on. It has a broad application prospect in the field of catalytic transesterification to prepare biodiesel. Therefore, it is of great significance to study the preparation of biodiesel catalyzed by ionic liquids in microtubules. In this paper, the physical and chemical properties of soybean oil were analyzed, and the composition ratio of each component in the raw material was determined. The relative molecular weight of soybean oil was calculated to be 870.31g mol-1,. The quantitative analysis method of biodiesel with methyl undecanoate as internal standard was determined based on gas chromatography. Then the batch catalytic reaction of biodiesel with traditional acid-base catalyst and solid catalyst was carried out. The results showed that the catalytic yield of Koh could reach 90.67 under suitable conditions. The effects of residence time, reaction temperature, molar ratio of alcohol-oil and catalyst on the transesterification of soybean oil and methanol were investigated by using PTFE microtubules as microreactors. The experiment was designed by response surface method and the experimental results were analyzed by Design-Expert to investigate the interaction between various factors on biodiesel yield. The optimum reaction conditions of transesterification catalyzed by KOH in microtubule reactor were determined as follows: residence time 100 s, reaction temperature 58 鈩，

本文编号：2209530