複合式薄膜蒸餾製程在各類共沸物分離製程之應用

Abstract

滲透蒸發具有節能、不用添加第三化學物質等好處，本研究探討其應用於複合式薄膜蒸餾系統之表現，並使用Aspen Plus進行模擬。 本研究分為兩大部分，其一，以複合式薄膜蒸發製程分離嘧啶(Pyridine)-水系統，並與以甲苯作為共沸劑之非均勻相共沸蒸餾，分為以總熱負載及年度總成本(TAC為目標函數作為比較。發現複合式薄膜蒸發系統應用在低共沸組成的嘧啶-水系統中，需要大量的昂貴薄膜，因此在經濟效應上並沒有其優勢。 其二，，以複合式薄膜蒸發製程分離異丙醇(IPA)-水系統，並與以dimethyl sulfoxide (DMSO)為萃取劑之萃取蒸餾系統，以IPA規格為99.9 mol%，目標函數為TAC做討論。由於IPA-水系統中共沸組成較高，因此除了原本設計程序外，也討論了使用薄膜系統直接達到所欲規格之可能性。結果顯示在規格為99.9mol%時，可使用較少薄膜即達到規格，但兩種不同的設計流程與DMSO為萃取計之萃取蒸餾系統相比，並無經濟優勢。

Pervaporation separation process can not only save the required energy but also not need a third component used in separation. This research discuss about the application of pervaporation using in hybrid distillation-membrane system and use Aspen plus to simulate the process. This research is divided into two part: first part is using hybrid distillation-membrane system to separate pyridine and water. Compare the process to heterogeneous azeotropic distillation using toluene as entrainer by using the total duty and total annual cost as objective function. We can find that it needs a lot of expensive membranes in series to separate the low azeotrope by hybrid distillation-membrane system which makes it not economically compatible. The second study is about the separation of isopropyl alcohol(IPA) by hybrid distillation-membrane system. Then, compare it with the extractive distillation by dimethyl sulfoxide (DMSO) as an extractant. The design spec of IPA is 99.9mol%. Despite of the original flow sheet design, IPA-water system can be separated by a stripper and membranes in series due to the high composition of the azeotrope. It shows that only need few membranes to achieve 99.9mol%. However, the hybrid system shows less economically compatible comparing to the extractive distillation due to the expensive membrane module.