複合式萃取-蒸餾系統於去水分離程序之應用

Applications of Hybrid Extraction-Distillation System in Dehydration Separation Processes

黃睿(Ruei Huang)

指導教授 ： 錢義隆

國立臺灣大學/工學院/化學工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201702310

摘要

在工業中有很多需要分離稀薄溶液共沸混合物之例子，進而獲得高純度規格並具有經濟價值之有機化合物和水分。使用傳統的共沸分離方法如變壓蒸餾或萃取蒸餾，通常需要建構前置提純塔，以便在進入共沸分離段之前可以除去大量的水，但這導致提純塔將消耗大量能量以達目的。本文中，提出了一種節省能源之複合式萃取-蒸餾程序來分離稀薄之混合物。此種更佳的分離方法主要優點是：利用自然產生之液-液分相，在不需要額外熱源的情況下於萃取塔中進行主要分離。
本文建構了異丙醇脫水系統，乙腈脫水系統和有機酸(丙烯酸與醋酸)脫水系統的詳細設計流程。通過基本物化性之安全性確認與選擇度之試驗，可以找出合適的萃取溶劑。之後於乙腈和異丙醇去水系統中，以正丙基氯為有效溶劑將乙腈和異丙醇萃取到萃取相中，並將水保持在萃餘相中。在有機酸脫水的情況下，應用叔戊基甲基醚進行液-液分離。在異丙醇和乙腈脫水系統之探討中，與傳統之萃取蒸餾程序相比大幅節省44.7% 和51.8%之年度總成本。而在有機酸脫水系統的部分，若與傳統之非均勻相共沸蒸餾系統相比，在主要有機酸成份為29.4 mol%與7.4 mol%之不同進料情況下，分別可以省下11.8% 與 52.6% 之年度總成本。

關鍵字

稀薄共沸混合物 ； 複合式萃取-蒸餾 ； 異丙醇脫水 ； 乙腈脫水 ； 丙烯酸和醋酸脫水 ； 程序設計

並列摘要

There are plenty of examples in industry for which the diluted aqueous mixture contains azeotropes need to be deeply separated to high-purity specifications. Using conventional azeotropic separation methods like pressure-swing distillation or extractive distillation, an energy-intensive pre-concentration column is often needed to remove a large portion of water before going into the azeotropic separation section. In this research, an energy-efficient hybrid extraction-distillation process is proposed for the separation purpose instead. The major advantage of this strategy is that the naturally-occurred liquid-liquid separation could be achieved without any extra heat source in the extraction column. In this work, the detailed design of three separation systems using this strategy are carefully and extensively investigated, namely, the isopropyl alcohol (IPA) dehydration system, acetonitrile (ACN) dehydration system, and the organic acid (acrylic acid and acetic acid) dehydration system. For designing the process, selecting the appropriate solvent is of the most importance, and this can be achieved through screening the material safety sheet and selectivity test. In this work, n-propyl chloride is selected as the solvent for acetonitrile and isopropyl alcohol dehydration system, while tert-amyl methyl ether is selected in organic acid dehydration case. Comparing with previous contributions based on conventional extractive distillation strategy, significant TAC reduction can be is found in both the IPA dehydration system (-44.8%) and in ACN dehydration system (-51.8%) by adopting hybrid extraction-distillation strategy. As for the organic acid system, there are two cases for different feed composition. When the fresh feed contains 29.4 mol% organic acid, TAC reduction is about 11.8% comparing with conventional heterogeneous azeotropic distillation strategy. If the fresh feed is diluted which only contains 7.4 mol% organic acid, TAC reduction will be 52.6%.

並列關鍵字

Diluted azeotropic mixture ； Hybrid extraction-distillation ； Isopropyl alcohol dehydration ； Acetonitrile dehydration ； Acrylic acid and acetic acid dehydration ； Process design

參考文獻

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