管壁正弦質量通量於迴流型套管質量交換器之效率研究

Improvement in performance of double-pass laminar counterflow concentric-tube mass exchangers under sinusoidal wall fluxes and external recycle

劉立謙(Li-Chien Liu)

指導教授 ： 何啟東

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2006年)

https://doi.org/10.6846/TKU.2006.00486

摘要

本研究是設計於圓形管中平行加裝一可滲透且忽略厚度之薄膜，形成一組外壁於正弦質量通量且具有迴流裝置之圓柱同心套管質量交換器，並建立數學模型與理論方程式，以及求得其解析解。此系統利用正交性質加以簡化問題後，可求得其近似解，濃度分佈及謝塢數(Sherwood number)，同時探討迴流效應對同心套管質量交換器的質傳效率之影響，並在系統中改變不同的迴流型式，探討薄膜位置及薄膜滲透率對此質量傳送系統之效率的影響，且與單行程無迴流的系統做比較。
在本文中，主要探討設計參數(即迴流型式、薄膜位置及薄膜穿透度)與操作參數 (即迴流量及體積流速)對圓柱同心套管質量交換器之影響。結果顯示，本系統在質傳格拉茲數大時，其效率提昇率有明顯改善，而不同的薄膜位置對質傳效率亦有顯著影響。在本文中，迴流系統因不同的迴流比值及薄膜位置而改變的能源消耗率也將與單行程系統比較，以探討雙套管質量交換系統之設計，在低能源消耗率時，求得質傳效率改善之最佳操作條件。

關鍵字

迴流 ； 圓管 ； 正弦管壁通量 ； 共軛格拉茲問題

並列摘要

A new double-pass mass exchanger with sinusoidal wall fluxes is obtained by inserting a permeable membrane into a circular tube. There are ten recycle types developed in this study to improve the device performance. The resultant mathematical formulation of such double-pass devices was derived theoretically and the approximation solution was obtained by using the orthogonality principle and forbenius method. The concentration distribution and mass transfer efficiency were represented graphically, and compared with those in single-pass devices of the same working dimensions. Considerable improvement of the device performance is obtainable by introducing recycle-effect concept for conducting double-pass operations. The effects of permeable-barrier position and recycle ratio on the mass transfer efficiency as well as on the of power consumption increment have also been discussed.

並列關鍵字

external recycle ； concentric circular-tube ； sinusoidal wall fluxes ； conjugated Graetz problem

參考文獻

1. Warren, L. McCable, Julian C. Smith, Peter Harriott, Unit Operations of Chemical Engineering, 5thed., McGraw-Hill, New York (1993).

2. Tasi, S. W., H. M. Yeh, A study of the separation efficiency in horizontal thermal diffusion columns with external refluxes, Can. J. Chem. Eng., 1985, 63, 406-410.

3. Hornut, J. M., H. Dhaouadi, S. Poncin, N. Midoux, J. M. Hornut, G. Wild, Hydrodynamics and flow regimes in external loop airlift reactor, Chem. Eng. Sci., 1999, 54, 5211-5221.

4. Korpijarvi, J., P. Oinas, J. Reunanen, Hydrodynamics and mass transfer in an airlift reactor, Chem. Eng. Sci. 1999, 54, 2255-2262.

5. Camarasa, E., E. Carvalho, L.A.C. Meleiro., A hydrodynamic model air-lift reactors, Chem. Eng. Processing, 2001, 13, 121-128.