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CO2-H2O和CO2-H2O-NaCl 体系的相平衡研究进展

吉远辉a; 吉晓燕b; 冯新a; 刘畅a; 吕玲红a; 陆小华a   

  1. a College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing
    210009, China
    b Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming
    82071, USA
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2007-06-28 发布日期:2007-06-28
  • 通讯作者: 吉远辉

Progress in the study on the phase equilibria of the CO2-H2O and CO2-H2O-NaCl systems

JI Yuanhuia; JI Xiaoyanb; FENG Xina; LIU Changa; LÜ Linghonga; LU Xiaohuaa   

  1. a College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing
    210009, China
    b Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming
    82071, USA
  • Received:1900-01-01 Revised:1900-01-01 Online:2007-06-28 Published:2007-06-28
  • Contact: JI Yuanhui

摘要: To study the feasibility of CO2 geological sequestration, it is needed to understand the
complicated multiple-phase equilibrium and the densities of aqueous solution with CO2 and
multi-ions under wide geological conditions (273.15—473.15K, 0—60MPa), which are also
essential for designing separation equipments in chemical or oil-related industries. For
this purpose, studies on the relevant phase equilibria and densities are reviewed and ana-
lyzed and the method to improve or modify the existing model is suggested in order to
obtain more reliable pre-dictions in a wide temperature and pressure range. Besides, three
different models (the electrolyte non random two-liquid (ELECNRTL), the electrolyte NRTL
combining with Helgeson model (ENRTL-HG), Pitzer activity co-efficient model combining with
Helgeson model (PITZ-HG)) are used to calculate the vapor-liquid phase equilib-rium of CO2
-H2O and CO2-H2O-NaCl systems. For CO2-H2O system, the calculation results agree with the
experi-mental data very well at low and medium pressure (0—20MPa), but there are great
discrepancies above 20MPa. For the water content at 473.15K, the calculated results agree
with the experimental data quite well. For the CO2-H2O-NaCl system, the PITZ-HG model show
better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52mol•L-1.
Bur for the NaCl concentration of 3.997mol•L-1, using the ELECNRTL and ENRTL-HG models
gives better results than using the PITZ-HG model. It is shown that available experimental
data and the thermodynamic calculations can satisfy the needs of the calculation of the
sequestration capacity in the temperature and pressure range for disposal of CO2 in deep
saline aquifers. More experimental data and more accu-rate thermodynamic calculations are
needed in high temperature and pressure ranges (above 398.15K and 31.5MPa).

关键词: CO2-H2O;CO2-H2O-NaCl;high temperature high pressure;phase equilibrium;density

Abstract: To study the feasibility of CO2 geological sequestration, it is needed to understand the
complicated multiple-phase equilibrium and the densities of aqueous solution with CO2 and
multi-ions under wide geological conditions (273.15—473.15K, 0—60MPa), which are also
essential for designing separation equipments in chemical or oil-related industries. For
this purpose, studies on the relevant phase equilibria and densities are reviewed and ana-
lyzed and the method to improve or modify the existing model is suggested in order to
obtain more reliable pre-dictions in a wide temperature and pressure range. Besides, three
different models (the electrolyte non random two-liquid (ELECNRTL), the electrolyte NRTL
combining with Helgeson model (ENRTL-HG), Pitzer activity co-efficient model combining with
Helgeson model (PITZ-HG)) are used to calculate the vapor-liquid phase equilib-rium of CO2
-H2O and CO2-H2O-NaCl systems. For CO2-H2O system, the calculation results agree with the
experi-mental data very well at low and medium pressure (0—20MPa), but there are great
discrepancies above 20MPa. For the water content at 473.15K, the calculated results agree
with the experimental data quite well. For the CO2-H2O-NaCl system, the PITZ-HG model show
better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52mol•L-1.
Bur for the NaCl concentration of 3.997mol•L-1, using the ELECNRTL and ENRTL-HG models
gives better results than using the PITZ-HG model. It is shown that available experimental
data and the thermodynamic calculations can satisfy the needs of the calculation of the
sequestration capacity in the temperature and pressure range for disposal of CO2 in deep
saline aquifers. More experimental data and more accu-rate thermodynamic calculations are
needed in high temperature and pressure ranges (above 398.15K and 31.5MPa).

Key words: CO2-H2O, CO2-H2O-NaCl, high temperature high pressure, phase equilibrium, density