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Towards Accurate Phase Equilibrium Modeling for Hydrogen Sulfide/Water Mixtures

  • Author / Creator
    Shiyu,Yin
  • Many deep gas wells contain acid gas components. Hydrogen sulfide (H2S) is one of the typical acid gases. Accurate flow simulations for H2S/H2O mixtures in reservoirs and wellbores require a proper thermodynamic model that is capable of accurately modeling the H2S/H2O mixtures under in-situ conditions. This study aims at screening and developing cubic-equation-of-state-based thermodynamic models that can well describe the phase behaviour of H2S/H2O mixtures. Peng-Robinson equation of state (PR EOS) (Peng and Robinson, 1976) and Huron-Vidal (HV) (Huron and Vidal, 1979) mixing rule are used as the basic modeling framework. The temperature-dependent binary interaction parameter (BIP) correlations in the HV mixing rule are established by matching the measured vapor-liquid/liquid-liquid equilibria (VLE/LLE) data for H2S/H2O mixtures collected from the literature. The experimental VLE/LLE data cover a temperature range of 273.150-627.85 K and a pressure range of 0.4-302.7 bar, while the experimental density data cover a temperature range of 294.35-705.53 K and pressures up to 350 bar. Different volume translation strategies are examined in terms of their accuracy in reproducing the measured density data for H2S/H2O mixtures. We employ PR EOS together with the optimal BIP strategy in the HV mixing rule to reproduce the mutual solubility of H2S and H2O in VLE/LLE. The calculated results show a good agreement with the experimental data, especially at high temperatures and pressures; the average absolute percentage deviation (%AAD) of 4.90% and 4.95% can be obtained for reproducing the vapor-phase H2O solubility and the aqueous-phase H2S solubility, respectively. With the inclusion of the volume translation model proposed by Abudour et al. (2013), PR EOS together with the optimal BIP strategy in the HV mixing rule shows a good performance in estimating the aqueous-phase density for H2S/H2O mixtures, i.e., an %AAD of 5.42% in reproducing the measured density data.

  • Subjects / Keywords
  • Graduation date
    Fall 2020
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-mxe6-nk26
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.