臺灣博碩士論文加值系統

本研究針對一個13X-分子篩填充床吸附空氣中水蒸氣之過程進行探討，主要研究之目的在於確立模擬此吸附過程之分析模式。研究中採用之分析模式有兩種，其一為具軸向質傳擴散之固體側阻力模式(solid-side resistance model，SSR)，另一為不具軸向質傳擴散之固體側阻力模式，研究中嘗試改變分子篩顆粒半徑(R)、填充床長度(L) 與固體側質傳擴散係數( )之大小，以觀察軸向質傳擴散效應之大小，研究結果顯示，此軸向質傳擴散對填充床吸附性能之影響極小，因此於分析中可被忽略。在實驗部份，此研究以直徑3.3 mm顆粒狀之13X分子篩做為填充床中之吸附劑，以進行吸附過程中填充床出口處空氣濕度(露點溫度)與溫度之動態實驗量測，並且在相同之操作條件下，以修正後之路易士數(Le)與固體側質傳擴散係數進行電腦模擬，電腦模擬採用不具軸向質傳擴散之SSR模式，此模擬之結果並與實驗量測之數據比較，結果顯示兩者具有良好的符合性。

The process in a packed bed with 13-X molecular sieves as adsorbent in adsorption of water was investigated. It intended to establish an accurate model for analyzing this process. Two solid-side resistance (SSR) models, one with considering axial dispersion effect and the other without considering axial dispersion effect were used in comparison. For various values of particle radius (R), packed-bed length (L) and solid-side mass diffusivity ( ), the axial dispersion effect was evaluated. The result shows that this effect on the adsorption performance is minor. Thus in general, it can be neglected in analysis. In experiment, 13-X molecular sieve particles with diameter of 3.3 mm were used as the adsorbent in a packed bed. The variations of temperature and dewpoint temperature at the exit were measured. Based on the same operating conditions, a computer simulation, using the SSR model without considering the axial dispersion effect, was performed. Modified Lewis number (Le) and modified solid-side mass diffusivity were adopted. It reveals that the simulation result matches well with the measured data.

目錄

中文摘要…………………………………………………………………… i
英文摘要…………………………………………………………………… ii
目錄……………………………………………………………………….. iii
圖目錄…………………………………………………………………….. v
符號說明………………………………………………………………….. vi

第一章 緒論……………………………………………………………..... 1
1-1 前言………………………………………………………… 1
1-2 相關研究…………………………………………………… 2
1-3 研究目的…………………………………………………… 3

第二章 理論模式…………………………………………………………. 5
2-1 球型13X分子篩顆粒之質量平衡模式………………….... 5
2-2 等溫吸附線……………………………………………….... 8
2-3 13X分子篩填充床之熱質分析模式……………………..... 8
2-3-1 填充床之質量平衡模式…………………….......... 8
2-3-2 填充床之能量平衡模式…………………….......... 9
2-4 無因次化…………………………………………………… 10
2-5 輔助資料…………………………………………………… 13

第三章 數值模擬分析與結果討論……………………………………..... 16
3-1 模擬數值方法……………………………………………… 16
3-1-1 分子篩內含水率變化分析…………………….… 16
3-1-2 分子篩之平均含水量…………………….……… 19
3-1-3 氣體側質量平衡方程式…………….…………… 19
3-1-4 固體側能量平衡方程式…………….…………… 20
3-1-5 氣體側能量平衡方程式…………….…………… 21
3-2 運算程序…………………………………………………… 21
3-2-1 運算過程…………………………………………. 21
3-2-2 程式運算之收斂條件……………………………. 22
3-3 模擬分析之結果與比較…………………………………… 25

第四章 實驗量測數據與模擬分析結果之比較……………………...….. 27
4-1 實驗目的……………………………………………...……. 27
4-2 實驗配置……………………………………………...……. 27
4-3 實驗量測程序……………………………………………… 28
4-4 實驗結果與模擬分析之比較……………………………… 29

第五章 結論與建議……………………………………………………..... 36

參考文獻……………………………………………………......................... 38

1. Ruckenstein, E., Vaidyanathan, A. S. and Youngquist, G. R., “Sorption by solids with bidisperse pore”, Chemical Engineering Science, Vol. 26, pp. 1305-1318, 1971.

2. Lee, L. K., “The kinetics of sorption in a biporous adsorption particle”, AIChE Journal, Vol. 24, pp. 531-534, 1978.

3. Ruthven, D. M., Lee, L. K. and Yucel, H., “Kinetic of non-isothermal sorption in molecular sieve crystals”, AIChE Journal, Vol. 26, pp. 16-23, 1980.

4. Rosen, J. B. “Kinetic of a fixed bed system for solid diffusion into spherical particles”, The Journal of Chemical Physics, Vol. 20, pp. 387-394, 1952.

5. Ruthven, D. M. and Lee, L. K., “Kinetic of non-isothermal sorption : systems with bed diffusion control”, AIChE Journal, Vol. 27, pp. 654-663, 1981.

6. Hsu, L. K. P. and Haynes, H. W. “Effective diffusivity by the gas chromatography technique: analysis and application to measurements of diffusion of various hydrocarbons in zeolite NaY”, AIChE Journal, Vol. 27, pp. 81-91, 1981.

7. Wakao, N., Tanaka, K. and Nagai, H., “Measurements of particle-to-gas transfer coefficient from chromatographic adsorption experiments”, Chemical Engineering Science, Vol. 31, pp. 1109-1113, 1976.

8. Rusmuson, A. and Neretnieks, I., “Exact solution of a model for diffusion in particles and longitudinal dispersion in packed bed”, AIChE Journal, Vol. 26, pp. 686-690, 1980.

9. Raghavan, N. S. and Ruthven, D. M., “Simulation of chromatographic response in columns packed with bidisperse structured particles”, Chemical Engineering Science, Vol. 40, pp. 699-706, 1985.

10. Pesaran, A. A. and Mills, A. F., “Moisture transport in silica gel packed bed-I”, Int. J. Heat and Mass Transfer, Vol. 30, pp. 1037-1049, 1987.

11. Pesaran, A. A. and Mills, A. F., “Moisture transport in silica gel packed bed-II”, Int. J. Heat and Mass Transfer, Vol. 30, pp. 1051-1060, 1987.

12. Karger, J. and Ruthven, D. M., “Diffusion in Zeolites and Other Microporous Solids”, pp. 237, Willy & Sons Inc., 1992.

13. 戴志光，13X-分子篩填充床之除濕應用與模擬分析，碩士論文，中興大學機械系，2002。

14. 王寶順，分子篩填充床吸附系統之電腦模擬，碩士論文，中興大學機械系，2004。

15. ASHARE Handbook-1981 Fundamentals, American Society of Heating, Refrigerating, and Air-Conditioning Engineers, 1981.