探討Peng-Robinson+COSMOSAC狀態方程式中分散項與溫度之關係;Discussion of the relationship between dispersion terms and temperature in Peng-Robinson+COSMOSAC equation of state

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Title:	探討Peng-Robinson+COSMOSAC狀態方程式中分散項與溫度之關係;Discussion of the relationship between dispersion terms and temperature in Peng-Robinson+COSMOSAC equation of state
Authors:	巫沅霖;Wu,Yuan-Lin
Contributors:	化學工程與材料工程學系
Keywords:	Peng-Robinson+COSMOSAC狀態方程式;Peng-Robinson+COSMOSAC equation of state
Date:	2016-07-28
Issue Date:	2016-10-13 12:43:16 (UTC+8)
Publisher:	國立中央大學
Abstract:	在許多化學工程領域的應用上，純物質與其混合物的蒸氣壓數據往往在程序的設計以及優化是非常重要的。近年來，Peng-Robinson + COSMOSAC狀態方程式的模型已開發並可提供具有可信度的物質熱力學性質相關的預測以及相平衡的預測，例如純物質的臨界性質、蒸氣壓與混合物的氣-液相平衡與液-液相平衡。此熱力學模型是以溶劑化理論與COSMO-SAC模型為基礎，利用量子力學以及COSMO溶劑化的計算結果來求得Peng-Robinson 狀態方程式的能量參數a與體積參數b。因此，此方法在理論上即可預測所有有機化合物的熱力學性質且不會有缺少參數的問題。本研究中，我們針對 Peng-Robinson + COSMOSAC狀態方程式的帶電溶合自由能中的分散項做了溫度函數的修正來提高模型在預測純物質蒸氣壓的精確度。在無增加任何參數量的情況下，修正後的方法顯示出更好的蒸氣壓預測結果。此方法共使用1125個有機化合物來結果分析，在修正後的方法顯示其完整的壓力取對數的誤差(ALD-P)為0.210，相較於原方法Peng-Robinson+COSMOSAC(2010)之誤差為0.234，從整體結果來看在蒸氣壓預測的精準度得到改善，尤其是對純物質低溫區的預測。特別是當沒有蒸氣壓實驗值的時候，此模型提供一套有效的方法來預測純物質的蒸氣壓。 ;The information of vapor pressure of pure substances and their mixtures is crucial in the field of chemical engineering because these data are necessary for the design and optimization of chemical engineering processes. Recently, the Peng-Robinson + COSMOSAC equation of state has been developed to provide reliable estimation of thermophysical properties and fluid phase equilibria, such as critical properties and vapor pressures of pure fluids and vapor-liquid and liquid-liquid equilibria of mixtures. This model, based on solvation theory and the COSMO-SAC model, utilizes results from quantum mechanical and COSMO solvation calculations to determine energy parameter and volume parameter in the Peng-Robinson equation of state. Thus, it theoretically can be used to estimate thermodynamic properties for all organic substances without issues of missing parameters. In this study, the Peng-Robinson + COSMOSAC equation of state is modified to improve its accuracy in predicting the vapor pressure of pure substances. The temperature dependence of the dispersion contribution is revised to provide better vapor pressure prediction without introducing new adjustable parameters, especially at lower temperature region (temperature between the triple point temperature and normal boiling point of a substances). A total of 1125 organic substances are considered in this work. The overall average logarithmic deviation for pressure (ALD-P) is 0.210 from the modified version, which is greatly improved while comparing to that from the original version (ALD-P = 0.234). This model is particularly useful when no experimental data is available in literature.
Appears in Collections:	[National Central University Department of Chemical & Materials Engineering] Electronic Thesis & Dissertation

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