利用熱與物質併合交換器之蒸餾塔

Use of a hybrid heat and mass exchanger for distillation

潘保儒(Pao-Ru Penn)

指導教授 ： 張煖

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2007年)

https://doi.org/10.6846/TKU.2007.00455

摘要

本論文提出一創新之裝置，係針對已提出之併合熱與物質交換薄膜模組(Hybrid heat and mass exchange membrane module)之修正設計。此設計使用殼管式多膜管裝置，液相以落膜方式於膜管外與氣相進行熱質傳，熱交換流體於膜管內與管外之氣相或液相進行熱傳。應用此設計之蒸餾塔，即HMEDiC (Heat and Mass Exchange Distillation Column)，屬於非絕熱(Diabatic)操作，可獲接近熱力學可逆之操作，提高能效。本論文針對氨水系統與苯－甲苯系統完成了HMEDiC之模擬分析研究。模擬分析使用Aspen Plus程序模擬軟體，配合以Fortran程式語言撰寫之嚴謹熱力學數學模式，並利用FLUENT軟體進行流力分析，決定最小膜厚。
針對氨水系統之分析結果顯示，在最小膜厚下，HMEDiC之熱能消耗低於填充式蒸餾塔。對氨水系統與苯－甲苯系統，具塔內熱交換之HMEDiC可操作於不具塔內熱交換時之兩倍進料流量，而單位進料之精餾段熱負荷、單位進料之氣提段熱負荷、單位進料之全塔可用能損失皆較低。HMEDiC之ㄧ重要特性為當進料流量固定時，並非膜厚愈小，產物純度愈高。當操作於具塔內熱交換之情況時，改變熱質傳係數之影響不大。

關鍵字

併合熱與物質交換薄膜模組 ； 非絕熱 ； 落膜 ； 單位進料之精餾段熱負荷 ； 單位進料之氣提段熱負荷 ； 單位進料之全塔可用能損失

並列摘要

An innovative device is proposed which is a revised design of a previously reported hybrid heat and mass exchange membrane module. The revised design make use of shell and tube type module. In the module, liquid forms a falling film at the tube outside and contacts with the shell side vapor phase, besides, heating or cooling fluid flows inside the membrane tube for heat exchange with the tube outside liquid or vapor phases. The module acts as a distillation, named HMEDiC (Heat and Mass Exchange Distillation Column) is investigated. The diabatic operation allows approching to thermodynamic reversible condition and increasing of energy efficiency. Applications of HMEDiC on ammonia-water and benzene-toluene systems are studied. For the HMEDiC, a rigorous mathematical model established on Aspen Plus with attached Fortran program is developed. Minimum flowrate required for forming a complete liquid film around the tube outside is determined by using the CFD package, FLUENT.

For ammonia-water system, under the minimum film thickness operation, energy consumption of a HMEDiC is lower than that of a packed column. For both ammonia-water and benzene-toluene systems, HMEDiC with and without column inside heat exchange are compared and the former allows about two times higher feed flowrate and significantly lower energy consumption in terms of per unit feed flowrate heat loads of rectification section and stripping section as well as exergy loss per unit feed flowrate. An important characteristic found is that for a fixed feed flowrate, decreasing of film thickness does not necessarily results in increasing of product purity. For a HMEDiC with column inside heat exchange, the effects of heat and mass transfer coefficients are not significant.

並列關鍵字

distillation ； membrane ； falling film ； heat transfer ； mass transfer ； computational fluid dynamics

參考文獻

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