• 作者： Lee, Liang-Sun; Kang, Huey-Ling; Kuo, Ming-Zhong
• 中文摘要： 在化工蒸餾分離程序中,共沸點的存在是蒸餾分離最困難的問題。欲分離共沸物需特別的考慮如改變操作壓力,利用共沸蒸餾或萃取蒸餾。但不管利用何種方法分離,混合物是否會形成共沸混合物,其共沸組成與溫度是必須先知道,才能考慮分離方法及操作條件,並且進行設計。一般汽液平衡的計算,若所用的活性係數模式需要實驗數據關聯出模式中的參數時,此種計算就不含有預估的能力。對於新的混合物若需要實驗數據決定是否為共沸混合物時,實驗數據就已提供所需的共沸組成及溫度,也就不必經由模式計算。本論文針對此缺點提出利用不必由實驗數據關聯而由組成成分的物理性質及熱力學性質直接估算出共沸成及溫度的方式。本論文利用Scatchard-Hildebrand、UNIFAC、 Veter-NRTL及Ash-Wilson四種不含參數的活性係數模式,有系統的針對不同性質的二成分及三成分混合物作預估,並與實驗值比較,測試我們所提出來的方法的可靠性。我們從文獻上蒐集262組混合物(共426組共沸實驗數據),將其分成8類,以汽液平衡理論配合上述種無參數模式,利用虛擬弧長連續數值法配合同倫法而預測。依我們計算的經驗而提出不同性質混合物以不同的模式計算的流程,我們所出的估算成功率可達97%。此計算流程對工業上確實可以提供相當有用的共沸資料作為設計之參考。
• 英文摘要： Distillation is important that it is still the first separation process to be considered for liquid mixtures separation in petroleum, petrochemical, and chemical industries. Some unique and interesting characteristics of this process such as tray arrangement, packing structure, handling of azeotropic mixtures make distillation still be full of challenge in design, control, and operation. The full acknowledge of the existence of azeotropic point and properties of a mixture would be very advantageous to design the apparatus and control systems for separating this mixture. In this study, a prediction methodology was proposed for determining the possible azeotropes of binary and ternary mixtures. This prediction procedure was based on the rigorous thermodynamic consideration and the parameter-free activity coefficient models of Scatchard-Hildebrand, UNIQUAC, Vetere-NRTL, and Ash-Wilson. The mathematical techniques of pseudo-archlength continuation and homotopy were used to locate the azeotropic compositions and temperatures of mixtures. About 262 azeotropic mixtures obtained from the work of Horsley (1973) were grouped into 8 categories and tested by the present prediction method. In this study, the vapor-liquid equilibrium experiments of the binary mixtures of isobutanol-n-pentanol, isobutanol-n-hexane, and n-pentanol-n-hexane were conducted and correlated by UNIQUAC, NRTL, and Wilson models. Then the predicted azeotropic behavior of these three mixtures by the proposed method was compared to the experimental data. The results of this study showed that the proposed method was about 97% success in predicting azeotrope for mixtures obtained from literature and from our experiments.
• 中文關鍵字： 共沸; 預估; 活性係數模式; 蒸餾
• 英文關鍵字： Azeotrope; Prediction; Activity Coefficient Model; Distillation