首先我們研究在Frazier熱擴散塔裝置之固定塔高總和下，等塔高之塔數對分離效率的影響。並且獲得一個可預測最佳板數以符合最大分離度之經驗式。我們取分離苯與正庚烷、水同位素中分離重水及回收重氫做為範例系統，且可有效改善其分離效果，實際上在Frazier裝置下，經驗式有其操作流率限制範圍。 其次，除了等塔高之最佳化板數外，改變其Frazier裝置，依等比遞變下之塔高亦被研究討論。並且獲得在等比遞變下之Frazier裝置，一個可預測最佳板數、最佳等比遞變係數以及最大分離度之經驗式。依照等塔高裝置之範例系統下去計算，我們可發現隨著流率的增加，其最佳板數隨之遞增，然而其最佳等比遞變係數會隨之遞減且塔高都是隨之遞增的，並且可得知等比遞增為其最佳化。我們利用其最佳等比遞變下之裝置可發現其分離效率遠比傳統裝置下之分離效果來得佳。 First, the effect of the number of columns (or the uniform column height) on the separation efficiency in thermal diffusion columns of the Frazier scheme at fixed sum of column heights has been investigated. The equations for predicting the optimum number of columns and the corresponding maximum separation were derived. The numerical examples for the separation of benzene-n-heptane system and water-isotopes mixture, as well as the recovery of deuterium from water-isotopes mixture, have been illustrated. Considerable enrichment in separation is obtainable if the number of columns (or the uniform column height) in a Frazier scheme is properly assigned for a certain flow-rate operation. Next, in addition to the device of optimal number of columns, the modified Frazier scheme, in which the column heights are also varied at a constant ratio, has been further investigated. The equations of the optimal column number, optimal column height ratio and the corresponding maximum degree of degree of separation in the modified Frazier scheme were derived by employing the method of variable univaniant. The numerical examples given before were also employed and calculated. It is found that as the flow rate increases, the optimal column number increases, while the optimal column height ratio decreases. Considerable improvement in separation can be achieved by employing the modified Frazier scheme rather than using the classic Frazier scheme, as well as even using the one only with the optimal column number.
