Experimental and Modeling Study on Phase Equilibria of Semiclathrate Hydrates of Tetra-n-butyl Ammonium Bromide + CH4, CO2, N2, or Gas Mixtures

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• 作者：Zhixin Liao ; Xuqiang Guo ; Yanyan Zhao ; Yiwei Wang ; Qiang Sun ; Aixian Liu ; Changyu Sun ; Guangjin Chen
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2013
• 出版时间：December 26, 2013
• 年：2013
• 卷：52
• 期：51
• 页码：18440-18446
• 全文大小：310K
• ISSN：1520-5045

文摘

Tetra-n-butyl ammonium bromide (TBAB) is most-widely used as a hydrate promoter in the separation of flue gases and CO₂ sequestration. Because of the complicacy of semiclathrate hydrate formed by TBAB aqueous solution and gases, few researchers have investigated the thermodynamic modeling of phase equilibria of semiclathrate hydrates. In this work, the CH₄鈥揘₂ hydrate dissociation conditions were determined in TBAB solution first, and then a thermodynamic model for gas hydrate proposed by Chen and Guo was extended for semiclathrate hydrates of gas mixtures in TBAB aqueous solution. The Patel-Teja equation of state (PT EoS) was used for calculation of the fugacity of the gas phase. To evaluate the activity of water and activity coefficients of TBAB in TBAB aqueous solution, a correlation on the basis of existing osmotic coefficient and activity coefficient values is employed. For modeling the hydrate phase, parameters for sII hydrates proposed in the Chen鈥揋uo hydrate model were used to calculate the fugacity of gases in hydrate phase, and parameters of TBAB were obtained from the correlation with the literature dissociation data for the pure gas + TBAB + water system. Then the presented model was used to predict dissociation data for the gas mixtures + TBAB + water system, and the results show acceptable agreement with other literature data and the experimental data for CH₄鈥揘₂ in this work.