生物柴油中C_(16)甲酯与C_(18)甲酯的减压精馏

Vacuum distillation of C_(16) methylester and C_(18) methylester in biodiesel

借助自制玻璃精馏塔,在减压操作条件下研究了麻疯果油制得的生物柴油中C16甲酯与C18甲酯之间的分离提纯特性。自制玻璃精馏塔直径为20 mm,内装不锈钢弹簧填料,高度为1 000 mm,其实际板数采用标准体系甲基环己烷-正庚烷在全回流条件下标定。在此基础上,比较了全回流条件下C16甲酯与C18甲酯的分离按理想体系计算的理论板数与实际板数的差异,并进行了麻疯果油制得的生物柴油中C16甲酯与C18甲酯的间歇精馏分离。结果表明:生物柴油中C16甲酯与C18甲酯间的精馏分离所需理论塔板数与实际板数基本吻合,可按理想体系进行工程设计;在回流比为1,塔顶操作压力为135 Pa的条件下,经间歇精馏可获得纯度(质量分数)为99%以上的C16,C18的脂肪酸甲酯产品,纯度99%以上C16甲酯收率为74.6%,纯度99%以上C18甲酯收率为92.8%。

The property of separation and purification of C16 methylester and C18 methylester in biodiesel prepared with jatropha oil was studied by using the home-made vacuum distillation device,whose batch distillation column is 20 mm with a height of 1 000 mm,loaded with highly-effective stainless steel material.Upon the infinite reflux operation,and on the basis of the ideal standards of methyl cyclopean-n-heptanes,the differences between the number of theoretical plates and the number of actual plates were compared,and the batch distillation of biodiesel（C16 methylester and C18 methylester）prepared with jatropha oil were performed.The results show that the number of theoretical plates figured out by C16 methylester and C18 methylester in the light of ideal system is almost consistent with the number of actual plates figured out by the ideal solution data,which verifies that the separation of C16 methylester and C18 methylester can be engineering designed in an standards system.The products of C16 methylester and C18 methylester with purity（mass fraction） above 99% are obtained through this separation（reflux ratio R=1,p=135 Pa）.The yield of C16 methylester with purity（mass fraction） over 99% is 74.6%,and the yield of C18 methylester with purity（mass fraction） over 99% is 92.8%.