SAFT modeling of multiphase equilibria of methane-CO₂-water-hydrate

详细信息    查看全文

• 作者：Mir Arsalan Hejrati Lahijani ; Chongwei Xiao ; ^{Chongwei.Xiao@tamuk.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Methane ; Carbon dioxide ; Hydrate ; Phase equilibria ; Langmuir constant
• 刊名：Fuel
• 出版年：2017
• 出版时间：15 January 2017
• 年：2017
• 卷：188
• 期：Complete
• 页码：636-644
• 全文大小：621 K

文摘

The vapor-liquid water-hydrate (V-Lw-H) phase equilibria are essential for multiple processes involving methane substitution by carbon dioxide. This work developed a model to predict the multiphase equilibria of CH₄<img border="0" alt="single bond" data-inlimg="/entities/sbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CO₂<img border="0" alt="single bond" data-inlimg="/entities/sbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">H₂O systems using molecule-based statistical association fluid theory (SAFT2) equation of states for the vapor and liquid phases and the statistical model by van der Waals-Platteeuw for the hydrate phase. The multiphase equilibria for CO₂<img border="0" alt="single bond" data-inlimg="/entities/sbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">H₂O and CH₄<img border="0" alt="single bond" data-inlimg="/entities/sbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">H₂O system were modeled for the temperature ranging from 273.15 to 288.15 K (13–700 bar) and 273.15 K to 299.15 K (26–500 bar), respectively. The CH₄<img border="0" alt="single bond" data-inlimg="/entities/sbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CO₂<img border="0" alt="single bond" data-inlimg="/entities/sbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">H₂O system were modeled at various temperatures ranging from 273.15 to 286.15 K (12–101 bar) with various CO₂ concentrations. In addition, the solubility of CH₄ and CO₂ under hydrate phase equilibria was computed in the temperatures of 273.15–286.15 K. The occupancy of CH₄ and CO₂ molecules in hydrate cavities was analyzed based on the calculation of Langmuir constants. The predicted multiphase equilibria and gas solubility are in good agreements with the experimental data with high accuracy.