Distillation Efficiency for Removal of Solved Minute Water in a Light Hydrocarbon

去除轻质烃中溶解微量水的蒸馏效率

• 批准号: 03650776
• 负责人: MUNAKATA Tsuyoshi
• 金额: $ 1.15万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650776/
• 关键词: DEHYDRATING DISTILLATION; DISTILLATION EFFICIENCY; VAPOR-LIQUID EQUILIBRIUM RELATION; HYDROCARBON-WATER SYSTEM; TRAY COLUMN; 炭化水素ー水系

The purpose of this work is to clarify the reason why it is said that the efficiency of dehydrating distillation in hydrocarbon-water system is extremely low. The research results obtained so far are summarized as follows. 1.Distillation experiment with a single-tray column In dehydrating distillation experiments for three systems of benzene-water,toluene-water,and hexane-water,it was shown that in a range of relatively high water concentration the tray efficiency reached as high as those for heptane-toluene system(about 70%),but in a low water concentration range the efficiency became low as the water concentration decreases. 2.Distillation experiment with a five-tray column In this experiment,we examined a concentration profile in a five-tray column by measuring the water concentration on each stage. The results showed that the water concentration below the third or fourth stage from the top of the column does not change and hence the limit of the dehydration exists.The tray efficien … More cy in item 1 above is the calculated result based on the vapor-liquid equilibrium (VLE) relation obtained in a range of relatively high water concentration,where the VLE ratio was assumed to be constant. Taking into account also the above results,it was considered that the reason of the efficiency drop may be largely due to the VLE relation in a range of low water concentration, which have not been yet measured. Therefore we conducted careful measurement of the VLE relation mainly in that range. 3.Measurement of the VLE relation in a range of low water concentration Using the liquid on the bottom stage of the five-tray column and molecular sieves as a dehydrating agent,we could measure the VLE relation up to about 2wt-ppm in water content. For benzene-water and hexane-water systems it was found that in a range above 100wt-ppm in water content the VLE ratio is almost constant,but in a range of the lower concentration it decreases gradually with decrease of the water concentration and tends to approach unity abruptly below 5wt-ppm. The calculated values of the tray efficiency based on this VLE data became higher than those obtained in item 1, but still gave its low value in a low water concentration range. Consequently,we could not reduce the reason of the efficiency drop to the VLE relation only. So we intend to clarify this questionable point in future. Less

这项工作的目的是澄清烃-水体系中脱水蒸馏效率极低的原因，迄今为止所获得的研究结果总结如下： 1.单塔板蒸馏实验。对苯-水、甲苯-水、己烷-水三个体系的脱水精馏实验表明，在较高的水浓度范围内，塔板效率达到与庚烷-甲苯一样高的塔板效率。系统（约70％），但在低水浓度范围内，效率随着水浓度的降低而降低。 2.五盘塔的蒸馏实验在该实验中，我们通过以下方式检查了五盘塔的浓度分布。测量各阶段的水浓度，结果表明，从塔顶算起的第三或第四阶段以下的水浓度没有变化，因此存在脱水极限。上述第1项中的塔盘效率为计算结果基于在较高水浓度范围内获得的汽液平衡（VLE）关系，其中VLE比率假设为恒定，同时考虑到上述结果，认为效率下降的原因可能是。很大程度上是由于低水浓度范围内的VLE关系，因此我们主要在该范围内仔细测量了VLE关系。 3.低水浓度范围内的VLE关系的测量。使用底部的液体通过五塔板柱和分子筛作为脱水剂，我们可以测量高达约 2wt-ppm 的水含量的 VLE 关系，发现对于苯-水和己烷-水体系，水含量在 100wt-ppm 以上的范围内。在含水量中，VLE比率几乎恒定，但在较低浓度范围内，它随着水浓度的降低而逐渐减小，并趋于突然接近计算值5wt-ppm。基于此 VLE 数据的塔盘效率值变得高于第 1 项中获得的值，但在测试的低水浓度范围内仍然给出较低的值，我们无法将效率下降的原因归咎于 VLE 关系。所以我们打算在未来澄清这个有疑问的点。