【作者】 李岩；

【导师】 姜绍通；

【作者基本信息】 合肥工业大学 ， 农产品加工及贮藏工程， 2007， 硕士

【摘要】 菜籽油皂脚是油脂加工过程的一种副产物，是在精炼工序的碱炼脱酸步骤中形成的，其总脂肪酸含量达到40％—60％，可作为重要的工业原料。国内在菜籽油加工副产品方面的开发程度低，多用于制皂，从而造成资源浪费，甚至污染环境。为此对皂脚的升值加工是一项重要的应用研究工作。本文主要研究了利用皂脚为原料，耦合分子蒸馏技术生产脂肪酸和生物柴油的工艺，优化了各自反应过程的最佳工艺条件，并对脂肪酸的水解废水(酸性甜水)和生物柴油生产中的副产物(碱性甜水)中的甘油进行了回收。试验研究的主要结论如下：(1)初步探索了分子蒸馏的操作温度对脂肪酸预先分离效果的影响。结果表明，在180℃的操作条件下，脂肪酸和甘油酯类得到了较好的分离；研究了不同酸价即不同脂肪酸含量的油脂在相同条件下的水解情况，结果表明，脂肪酸含量的降低比较明显的提高了水解的程度。(2)以水解率为考察指标，对脂肪酸水解过程通过正交试验设计进行优化，得到最佳工艺参数组合，水用量为100％，催化剂用量为3.2％，硫酸用量为6％，于150℃下水解5h，一次水解率可达到97.57％。(3)以酯化率为考察指标，根据单因素和正交试验优化出第一次甲酯化的最优条件为：催化剂(硫酸)用量为1.5％，甲醇用量为200％，反应温度为60℃，反应时间为2h，酯化率达到97.2％。在一次甲酯化的基础上进行的二次甲酯化，结果表明：酸价降为1.67mgkOH／g样品，达到了转酯化反应的基本要求。以转化率为考察指标，根据单因素和正交试验优化出转酯化的最优条件为：催化剂(甲醇钠)用量为0.5％，甲醇用量为25％，反应温度为65℃，反应时间为30min，此时转化率能达到95.84％。通过两次甲酯化—转酯化反应酸化油较好的转化为生物柴油。(4)采用气质联用仪对精制脂肪酸和生物柴油的纯度进行检测，其含量分别达到98.01％和98.18％。(5)酸性甜水通过脱酸、脱胶、碱处理、浓缩和蒸馏等操作步骤，甘油的纯度达到98.62％，回收率为77.87％；碱性甜水通过稀释中和、离心、浓缩和蒸馏等，甘油的纯度达到99.01％，回收率为82.78％。从结果可以看出，甘油的分离程度和产率达到较好的水平。更多还原

【Abstract】 Rapeseed oil soapstock is a by-product from the vegetable oil refining.which is formed during the deacidification with alkali.The content of total fatty acids reaches 40%—60%,which can be exploited as an industry material.Nevertheless,it hasn’t been comprehensively utilized.It is mostly used to make soaps,thus leading to the waste of resources and pollution of environment. Therefore, it’s a meaningful task to work on the value-added process of soapstocks.The preparation of fatty acids and biodiesel from soapstock coupling molecular distillation was studied and the respective reaction conditions were optimized.Then the glycerol was recovered from acidic and alkaline sweet water.The main conclusions of the experiments were as follows:(1)The effect of deacidification temperature on the separation of fatty acid was simply investigated.The results showed that fatty acids and triglycerides were efficiently separated at 180℃.The hydrolysis of glyceride with different acid value indicated that the degree of hydrolysis was improved with the decrease of fatty acid content.(2)The process of fatty acids production was optimized by orthogonal emperiments with ratio of hydrolysis as the index.The optimal conditions were:the amount of water was 100%, the amount of catalys was 3.2%, the amount of sulfuric acid was 6%,and reaction time was 5h at 150℃,under which the ratio of hydrolysis was 97.57%.(3)The optimal conditions of the first methyl esterification through the optimization of single factor and orthogonal experiments were:the amount of sulfuric acid as catalyst was 1.5%,the amount of methanol was 200%,the reaction temperature was 60℃,and the reaction time was 2h,under which the ratio of esterification was 97.2%.And then the second esterification was conducted on the basis of the first one.The results showed that the the requirement of following transesterification was reached while the acid value was lowered to 1.67mgKOH/g.The optimal conditions of the transesterification through the optimization of single factor and orthogonal experiments were:the amount of sodium methoxide as catalyst was 0.5%,the amount of methanol was 25%,the reaction temperature was 65℃,and the reaction time was 30min,under which the ratio of conversion was 95.84%.The biodiesel was well produced through twice esterifications followed by transesterification.(4)The purities of both fatty acids and biodiesel were detected by GC-MS,which were 98.01% and 98.18% respectively.5.The purity and yield of glycerol that was recovered through the procedure of deacidification,degumming,alkaline processing,condensation and distillation was 98.62% and 77.87% respectively. Accordingly,the purity and yield of glycerol that was recovered through the procedure of neutralization、centrifugation、condensation and distillation was 99.01% and 82.78%.A high level of separation and yield was obtained.更多还原