• 作者： Chiang, Chien-Lih; Liu, Yu-Chau
• 中文摘要： 本文以水為連續相, 甲苯為分散相, 探討直徑 7.6公分, 18級的第三型薛氏萃取塔內連續相的軸向分散。利用脈衝--- 響應的方法所得的滯留時間分佈, 再藉分散和逆流模式以求得連續相的軸向分散係數。另外, 利用追蹤劑的階段變化,再由上游端取樣的方法可求得以E/sub b/和.alpha.'分別表示的卷流擴散(eddy diffusion)和逆混合( backmixing)係數。實驗結果顯示連續相的軸向分散係數不只受轉速, 也受連續相流量的影響。然而, 卷流擴散係數只隨轉速的增加而增加, 而連續相流量的影響並不顯著。本文所得的E/sub a/值較文獻上第一型和第二型薛氏萃取塔所得的E/sub b/值大。另外, 由不同的數學模式和邊界條件所得的結果, 差異甚大。
• 英文摘要： Axial dispersion of continuous phase was investigated in a thirdtype Scheibel 7.6cm diameter, 18-stage column with toluene (dispersed)-water (continuous)as the liquid-liquid system. Axial dispersion coefficient of the continuous phase was determined by dispersion and backflow models from the residence time distribution obtained by the impulse-response method. Also eddy diffusion and backmixing coefficients, characterized by E/sub b/ and .alpha.', respectively, were obtained from upstream sampling method with a step-change of tracer solution. The experimental results indicate that the axial dispersion coefficient of continuous phase depends not only on the rotor speed, but also on the continuous-phase flow rate. However, the eddy diffusion coefficient increases only with increasing rotor speed, and the influence of continuous- phase flow rate is not significant. The values of E/sub a/ obtained from this study are greater than those reported for the first type and the second type Scheibel columns. In addition, the results obtained are quite different with various mathematical models and boundary conditions.
• 中文關鍵字： 軸向分散; 卷流擴散; 逆混合; 薛氏萃取塔; 脈衝一響應方法
• 英文關鍵字： Axial Dispersion; Eddy Diffusion; Backmixing; Scheibel Column; Impulse-Response Method