發(fā)布時間：2018-07-09 09:44

  本文選題：生物柴油 + 酯交換反應��； 參考：《上海應用技術學院》2015年碩士論文

【摘要】：生物柴油(即脂肪酸甲酯)以其良好的再生性和環(huán)保性正逐漸成為化石燃料的替代品。生物柴油通常是通過植物油或動物油脂與甲醇的酯交換反應而制得。催化劑的性能是酯交換反應的關鍵,目前主要集中于多相催化劑尤其是固體堿催化劑的研究。本論文對生物柴油產(chǎn)物的分析方法進行了比較研究；采用燃燒法制備了鈣鋯復合氧化物固體堿,研究了鈣鋯摩爾比對固體堿物化性能和催化酯交換反應性能的影響,并對其堿性與催化活性之間的關系進行了初步探討；考察了稀土金屬La對鈣鋯固體堿的促進作用。得到以下主要結論：1、甘油滴定法測定生物柴油產(chǎn)率步驟繁瑣,且由于測定原理上存在一定局限導致重復性和準確性不夠理想。色譜法需要大量的標準樣品,測試時間較長。核磁共振法(NMR)相對簡單方便且準確性和重復性好。2、隨著鈣鋯摩爾比的增加,催化劑的BET比表面減小,表面的總堿性位則先增加后減小,在鈣鋯摩爾比為8：2時,總的堿性位數(shù)量達最大值。隨著鈣鋯摩爾比的增加,堿位強度逐漸增強,并導致TOF值的增大。最佳組成的催化劑在催化劑用量為1.25 wt%,醇油比為25：1,反應溫度為65℃的條件下,反應時間為2h和3 h,生物柴油的轉(zhuǎn)化率分別達到93.9%和98.0%。3、尿素硝酸鹽燃燒法是一種快速有效的制備CaO-ZrO2固體堿催化劑的方法。最佳制備條件為：燃料用量為化學計量比的150%,起燃溫度為500℃,燃燒產(chǎn)物不需要進一步焙燒。4、La的添加顯著增加了CaO-ZrO2催化劑的BET比表面,增大了孔容孔徑。90%轉(zhuǎn)化率的時間由2 h縮短至0.5 h。催化活性提高與催化劑的孔徑和比表面變大有關。5、La的添加提高了CaO-ZrO2固體堿的抗水性和使用壽命。當大豆油中含有8.0 wt%的水時,反應1h轉(zhuǎn)化率達90%以上,相同條件下的CaO-ZrO2轉(zhuǎn)化率僅15%。當La的添加量為5%時,催化效率為95%,催化劑的循環(huán)使用次數(shù)從3次提高到了6次。
[Abstract]:Biodiesel (fatty acid methyl ester) is becoming a substitute for fossil fuels for its good reproducibility and environmental protection. Biodiesel is usually produced by transesterification of vegetable oil or animal oil with methanol. The performance of catalyst is the key of transesterification, and it is mainly focused on heterogeneous catalyst, especially solid base catalyst. In this paper, the analytical methods of biodiesel products were compared, the solid base of calcium zirconium composite oxide was prepared by combustion method, and the effects of molar ratio of calcium to zirconium on the physicochemical properties and catalytic transesterification of solid bases were studied. The relationship between the alkalinity and the catalytic activity was discussed, and the promoting effect of rare earth metal La on the calcium zirconium solid base was investigated. The main conclusions are as follows: 1. The steps of measuring biodiesel yield by glycerin titration are tedious, and the repeatability and accuracy are not satisfactory due to the limitation of the determination principle. Chromatography requires a large number of standard samples, the test time is longer. Nuclear magnetic resonance (NMR) method is relatively simple and convenient, and has good accuracy and repeatability. With the increase of the molar ratio of calcium to zirconium, the BET specific surface of the catalyst decreases, while the total basic potential of the surface increases first and then decreases, at 8:2 the molar ratio of calcium to zirconium increases. The total number of basic sites reached the maximum. With the increase of the molar ratio of calcium to zirconium, the base potential strength increases and the TOF value increases. The optimum composition of the catalyst is 1.25 wt, the ratio of alcohol to oil is 25: 1, the reaction temperature is 65 鈩，

本文編號：2108956