Design and Control of Separation for Ternary Azeotropic Mixtures System Aided by Liquid-Liquid Separation
| Autor: | Kai-Yang Lin, 林楷揚 |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 This work consists of two mixture systems and mainly discusses how to use the existing liquid-liquid phase separation region in the three-component mixture system to assist the separation. The first system is the separation process for the mixture of isopropyl ether, isopropyl alcohol and water. By using liquid-liquid phase separation combined with pressure swing distillation, the distillation boundary can be kept away from the operating point and the distillate flow rate of the column is greatly reduced, so that the recirculation in the system is reduced and the energy consumption is also reduced. Finally, after partial heat integration being performed between the low pressure column and the high pressure, the calculated annual total cost is reduced 38.6% compared to the conventional pressure swing distillation. This study also discusses the dynamic simulation and control of this heat-integrated design process. After considering the open loop and closed loop sensitivity test, the single point temperature control and the pressure compensation temperature control are used, and finally the closed-loop disturbance test is performed to confirm that the system can still maintain high purity product specifications under disturbance. The second system is a separation process for a mixture of benzene, isopropanol and water. The system contains three two-component azeotropes and one three-component azeotrope, and the distillation boundary divides the three-component phase diagram into three regions. Since the feed composition is located in the liquid-liquid phase separation zone, the fresh feed directly enters a decanter, and the aqueous phase and the organic phase are obtained. The two phases, which are in different distillation area, enter a distillation column respectively and the product can be get from the bottom. By adjusting the reflux ratio of the distillation column, the mixture of the two column distillate can be located in the distillation zone where the third product is located. After the mixed stream enters a distillation column, the third product can be obtained at the bottom of the column. The distillate composition is close to the three-component azeotrope composition. The distillate is recycled back to mix with the fresh feed and then goes into a decanter. Finally, partial heat integration is performed and then TAC is calculated. The result shows 61.4% savings in cost compared to conventional pressure swing distillation. By discussing the above two separation design process, it can be found that the method used in this study can greatly reduce the overall recirculation of the system to reduce the operating cost compared with the conventional pressure swing distillation. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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