內隔壁式蒸餾塔應用於非理想系統之穩態設計

Abstract

相較於傳統的蒸餾序列，內隔壁式蒸餾塔（DWC）可以節省更多的能量與與設備成本。然而，內隔壁式蒸餾塔在設計上也較為困難，因為較傳統序列擁有更多的設計自由度。在本研究中，我們針對三種型態之分隔式蒸餾塔設計出一套捷徑式設計法以應用於非理想系統中。以文獻回顧中提到的設計方法為基礎，加以修正改良。最主要的改變是採用Aspen Plus為模擬工具，此舉可以使設計方法不必在基於失真的固定相對揮發度假說，能夠應用在相對揮發度隨著溫度改變較大的系統中。研究中包含一系列的嚴謹模擬和兩個實例探討以測試此設計方法之實用性。結果顯示設計方法計算出的年度成本和最小年度成本相去無幾，而我們也可以應用此方法來做為嚴謹設計時的一項指標。

Divided-wall columns (DWCs) can save energy and capital cost compared with traditional distillation columns. However the design of DWCs is more difficult because there are more degrees of freedom. In this work, we develop a general design method for non-ideal systems for all three types of DWCs. Based on the design method by literature, we make some evolutions. The main modification is to use Aspen Plus simulation instead of the short cut equation based on constant relative volatility assumption. A series of rigorous simulations are applied to two real systems in order to show the performance. The results show that the total annual cost (TAC) based on the design method is close to the minimum total annual cost. Finally the manipulate variable designed can be used as the initial guess of the optimal total annual cost design case.