酶法合成生物柴油的研究
文献类型：学位论文
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| 作者 | 罗文 |
| 学位类别 | 硕士 |
| 答辩日期 | 2007-06-08 |
| 授予单位 | 中国科学院广州能源研究所 |
| 授予地点 | 广州能源研究所 |
| 导师 | 袁振宏 |
| 关键词 | 生物柴油 脂肪酶 固定化 转酯化 动力学机制 |
| 其他题名 | A research on enzymatic biodiesel production |
| 中文摘要 | At present, the global huge consumption of energy and environmental degradation are becoming more and more serious, so it is urgent for mankind to protect nature and develop alternate fuel. Derived from vegetable oils or animal fats, biodiesel is a fuel consisting of alkyl esters of fatty acids. It is attracting increasing attention as an alternative, non-toxic, biodegradable and renewable diesel fuel. The enzymatic synthesis of biodiesel has been becoming more and more attractive because it overcomes some drawbacks of chemical synthesis. In this study, the immobilization process of lipase was studied and experiments on the biodiesel production catalyzed by this immobilized lipase were performed.Also the kinetics of the transesterification to biodiesel was also studied. The results were listed as follows: 1)lipase from Candida sp. 99-125 was immobilized on aminated controlled pore glass surfaces by the cross-linking process. The optimal conditions for immobilization were obtained. After immobilization, the thermal stability, pH stability（when pH＞8）and tolerance to organic solvents of lipase was improved apparently. 2)Preparation of biodiesel by transesterification from rapeedseed oil catalyzed by lipase was discussed. It was found that methanol-to-oil molar ratio, kind of organic sovlent, volume of solvent, reaction time, water content and glycerol content had important effects on biodiesel yield. 86% biodiesel yield was achieved under the optimal conditions. The half-life of immobilized lipase was longer than 390 hours. 3)The product glycerin was absorbed to the surface of controlled pore glass carrier, which decreased enzyme activity. After 30 hours' reaction under the optimal conditions, the carrier was cleaned and centrifuged to remove the glycerin. The cleaned carrier was returned to the above reaction solution and the reaction continued for 4h. The conversion rate can be improved by 3%. 4)Established an accurate and complex kinetic model for the transesterification to biodiesel, namly, Ordered Bi-Bi mechanism which was proved to better simulate the reaction with comparison to classical Ping-Pong Bi-Bi mechanism. The reaction sequence is as follows: According to the Ordered Bi-Bi mechanism, the acyl donor (triglyceride) first binds with the enzyme and forms an acyl-enzyme complex (E.S). The second reactant (alcohol) then combines with (E.S) to form ternary complex. This ternary complex then isomerizes to another ternary complex, which sequently releases the product of glycerol and fatty acid ester. 5)Only the inhibition of alchol on lipase, which was competitive, was observed in the transesterification to biodiesel. At low triglyceride concentration, alcohol inhibition was significant and the initial rate of reaction was high. Much higher alcohol concentrations were required for inhibition to take place at high substrate concentrations. 6)Cold filter plugging point was impacted mainly by saturated fatty acid ester components, little by unsaturated fatty ester. High content of saturated fatty acid ester with high melting point made high cold filter plugging point of hogwash-oil-biodiesel. 7)Cetane number and viscosity were affected by chain length, numbers of double bond and content of fatty acid ester. Viscosity and cetane number increased with chain length and with increasing degree of saturation. Kinematic viscosity of biodiesel could be well predicted by a logarithmic equation for viscosity. |
| 语种 | 中文 |
| 公开日期 | 2011-07-10 ; 2011-07-15 |
| 页码 | 82 |
| 源URL | [http://ir.giec.ac.cn/handle/344007/4011]  |
| 专题 | 中国科学院广州能源研究所 |
| 推荐引用方式 GB/T 7714 | 罗文. 酶法合成生物柴油的研究, A research on enzymatic biodiesel production[D]. 广州能源研究所. 中国科学院广州能源研究所. 2007. |
入库方式： OAI收割
来源：广州能源研究所
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