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Development of Calculation Method for Heterogeneous Azeotropic Distilllation Based on Heat and Mass Transfer

基于传热传质的多相共沸精馏计算方法的发展

基本信息

批准号：
06650853
负责人：
KOSUGE Hitoshi
金额：
$ 1.28万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650853/
关键词：
Distilllation Mass Transfer Heat Transfer Calculation Method

项目摘要

The objectives of this study are to investigate the effect of operating conditions on the heat and mass transfer rates in heterogeneous azeotropic distilllation, and to develop a new calculation method for heterogeneous azeotropic distilllation based on the heat and mass transfer rates.A new wetted-wall column with two stills is set up, where oilish and aqueous liquids of thr feed are heated separately in the stills so as to vary the inlet vapor concentrations. The experiments of heterogeous azeotropic distilllation for the ethanol-benzene-water system are carried out undet total reflux conditions with wide ranges of vapor flow rates and concentration. The dimensionless vapor-phase diffusion flux of each component obtained in an oil-rich liquid region shows good agreement with the theoretical values of the mass transfer rates with laminar flow in a circular tube. However the observed vapor phase diffusion flux obtained from an water-rich liquid show larger values than the theory.A new calculation method for heterogeneous azeotropic distilllation is developed based on heat and mass transfer. The simulation of heterogeneous azeotropic distilllation shows a large difference of concentration driving force of benzene and water between the bottom and top of the column, and also shows the variation of the concentration driving forces of those components along the column. This may cause the larger mass transfer rates than the theoretical values. The representative concentration driving force obtained from the distilllation experiments might no represents the real concentration driving force. These results indicate another experiment with a shorter distilllation column. Actually, the calculated vapor an liquid concentrations and reflux flow rates in whole two liquid regions, while the average diffusion flux in and oil-rich two liquid region are still larger than the theoretical values.

本文旨在研究操作条件对非均相共沸蒸馏传热传质速率的影响，并建立一种基于传热传质速率的非均相共沸蒸馏计算方法。建立了一种新型双釜湿壁塔，其中在蒸馏器中分别加热THR进料的油性液体和水性液体，以改变入口蒸气浓度。在全回流条件下，对乙醇-苯-水体系进行了非均相共沸精馏实验。在富油液相区得到的各组分的无因次气相扩散通量与圆管层流传质速率的理论值吻合较好。在此基础上，提出了一种基于传热传质的非均相共沸精馏计算方法。对非均相共沸精馏过程的模拟表明，苯和水的浓度驱动力在塔底和塔顶存在较大的差异，并显示出这些组分的浓度驱动力沿塔沿着方向的变化。这可能导致传质速率大于理论值。由实验得到的代表性浓度驱动力可能不能代表真实的浓度驱动力。这些结果表明另一个实验采用了较短的蒸馏柱。实际上，计算得到的整个两液区的汽液浓度和回流流量，以及富油两液区的平均扩散通量仍大于理论值。