【作者】 林涛；

【导师】 许松林；

【作者基本信息】 天津大学 ， 制药工程， 2009， 硕士

【摘要】 分子蒸馏(Molecular Distillation)也称短程蒸馏(Short Path Distillation),是一种特殊的蒸馏分离技术。自上世纪中叶问世以来,受到了人们的高度重视。近几十年来在国际上发展迅速,在工业上已得到广泛的应用。本文对分子蒸馏浓缩合成维生素E进行了研究,确定了在刮膜器转速200 r/m、操作压力0.1 Pa、蒸馏温度158℃、进料速率110 mL/h的条件下,经分子蒸馏处理后的合成维生素E纯度可由91%提高到98%以上。另外,本文根据实验数据进行拟合,得到了在一定范围内准确度较高的馏出物轻组分浓度预测式,对今后的实际生产应用和理论研究具有指导意义。本文还对刮膜式分子蒸馏过程中,蒸发器上液膜形态进行了研究。设计了针对液体在蒸发壁面上的流动速度us,液体的黏度μ,密度r,表面张力σ和转子的转速ur等五个因素的考察实验,通过实验观察,将液体在蒸发器上成膜状态分为完全成膜与不完全成膜两类。并以此为基础,对各个影响因素进行量纲分析,借助1st opt软件得到分子蒸馏成膜临界速度关联式,并通过实验验证了关联式在一定范围内具有合理性。本文以Langmur-Knudsen蒸发理论为基础,结合刮膜式分子蒸馏过程液膜形态研究及系数修正法,提出了一种新的分子蒸馏过程模型。根据蒸发器表面上液膜形态的不同,将整个液体流动过程分成若干区域。对每个区域进行物料衡算,组分衡算,以及蒸发速率方程的推导,蒸发系数的确定,得到相关的数学方程组,利用MATLAB软件解方程组,计算可得出分子蒸馏过程的最终产品浓度。然后将模型应用于正辛酸-十二烷醇以及合成维生素E分离实验,验证了模型的合理性。并分析了产生实验值与模拟值相对误差的原因,为进一步完善刮膜式分子蒸馏过程模型奠定了基础。更多还原

【Abstract】 Molecular Distillation (MD), also termed as Short Path Distillation (SPD), is a special distillation technology, which has been paid attention to by many people since it had been invented in the 50’s of last century. This technique has been applied more and more internationally in the recent decades of years.This paper studied on the concentration of the synthetical vitamin E by molecular distillation. The experimental results showed that the product purity was above 98% under the conditions:wiper speed 200 rpm,operation pressure 0.1Pa,distillation temperature 158?C,feed rate 110 mL/h. In addition, the experiment data was deducted and the concentration predictor formula of the more volatile component was gotten, which will be of significance to the future produce and study.In addition, the film status on the evaporation surface of the molecular distillation has been studied. The experiment was designed to study the effect of the flow velocity of the liquid on the evaporation surface us, the viscosity of the liquidμ,the density r,surface tensionσ, the rotation speed of the wiper ur on the film status. Through the experiment, the film status was divided into two kinds, complete film and incomplete film. On the basis of the above, dimension analysis was adopted to the above five factors, and the complete-incomplete film critical parameter formula was obtained with the software 1st opt. Then the validation of the formula was carried on with the experimental data.Finally, with the evaporating rate theory provided by Lanmuir-Knudsen and Kawala’s theory about evaporating rate coefficient, combined with the study on the film status and the coefficient remodeled method, an original model was adopted to the wiped film molecular distillation. According to the alternant appearance of the two different film statuses, the whole process of the film flow was divided into several areas. The material balance calculation and the component balance calculation were applied to every area and then the mathematical model was gotten. The mathematical model was solved with the software MATLAB. The model was also used in the simulation of caprylic acid-lauryl alcohol and the synthetical Vitamin E, compared with experimental outcome, analyzed the relatively error between experiments and simulations to further check the rationality of the model, which is beneficial to establish a more perfect model in the future.更多还原