操作条件对分子蒸馏纯化不饱和单甘酯的影响

通过单因素试验和正交试验研究了蒸发温度、进料流速、进料温度和冷凝温度对分子蒸馏纯化不饱和单甘酯时轻相/进料质量比D/F的影响,试验结果表明:影响D/F值的因素从大到小为:蒸发温度进料流速进料温度冷凝温度.建立了轻相中单甘酯和甘二酯的含量对不同蒸发温度的二次回归方程,为验证方程的可靠性,分别在进料流速为0.71、1.06、1.42mL/min,蒸发温度为150～200℃的条件下进行试验,将模型值同实验值进行比较,发现数学模型值和实验值很吻合.文中还考察了不同操作条件下不饱和单甘酯的回收率,当蒸发温度在170～190℃之间、进料流速为0.71mL/min、进料温度为70℃、冷凝温度为60℃时,只通过一步分子蒸馏,轻相中单甘酯的纯度便可提高到80%以上,回收率在60%～80%.

Effect of Operation Conditions on Purification of Unsaturated Monoglyceride via Molecular Distillation

In this work, one-factor-at-a-time experiments and orthogonal test (L9(3)4) were carried out in order to study the operating conditions such as evaporate temperature (ET), feed flow rate (Q), feed temperature (FT) and condenser temperature (CT) on the effect of mass ratio D/F when purification of unsaturated monoglycerides by molecular distillation. The factors influence the D/F were listed in a decreasing ordeals follows: ET>Q>FT>CT. Mathematics model used to predicting the content of MAG and DAG in the distillate stream were established under ET from 150-200℃, the models fill those experiment dates very well when compare the values predicted by the models and the experimental data. Finally, the dependence of MAG recovery (in the distiilate stream) were conducted, if a product with a minimum of 80% of MAG is desired, the best distillation condition obtained in the experimental range studied is: Q, FT, CT at 0.71ml/min, 70℃, and 60℃ respectively and ET from 170-190℃, at these conditions, the MAG recovery is approximately from 60% to 80%.