An experimental approach for measuring carbon dioxide diffusion coefficient in water and oil under supercritical conditions

Mohammad Sadegh Sharafi*, Mehdi Ghasemi, Mohammad Ahmadi, Alireza Kazemi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Several direct or indirect approaches have been proposed to measure diffusion coefficient of gases into liquids. The main complexity of indirect techniques such as pressure decay method is interpreting early pressure–time data which strongly affected by incubation period effect or convective instability. In the current approach, accurate apparatus and precise experimental setup including a high pressure and temperature PVT cell, a high precision Sanchez pump, heating and recording sub-system are implemented and a novel data analysis procedure is applied to modify pressure decay method. The effect of incubation period is reduced remarkably and diffusion coefficient of carbon dioxide in water in wide range of pressures and temperatures is determined and the effects of temperature, pressure and carbon dioxide phase alteration from gas to supercritical are investigated and the value of uncertainty is estimated. Furthermore, diffusion coefficient of CO2 and methane in an oil sample from one of the Iranian southwest oil formations is determined precisely using the experimental approach while no incubation period is detected. The results showed that incubation period duration decreases with increasing diffusion coefficient. Additionally, when CO2 state is gas, rate of increasing diffusion coefficient with pressure is decreased with temperature and when CO2 state is supercritical, the rate of increasing diffusion coefficient with pressure is decreased significantly.

Original languageEnglish
Pages (from-to)160-170
Number of pages11
JournalChinese Journal of Chemical Engineering
Publication statusPublished - Jun 2021
Externally publishedYes


  • Diffusion coefficient
  • Incubation period
  • Modified pressure decay method
  • Solubility uncertainty

ASJC Scopus subject areas

  • Environmental Engineering
  • Biochemistry
  • General Chemistry
  • General Chemical Engineering

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