Browsing by Author "Khalifi, Mohammad"

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    Experimental Measurement of Diffusion Coefficient of Gaseous Solvents in Liquids
    (2021-05-12) Khalifi, Mohammad; Abedi, Jalal; Hassanzadeh, Hassan; Moore, Robert Gordon; Mehta, Sudarshan; Zhang, Yan; Johansen, Craig; Hejazi, Hossein
    The molecular diffusion coefficient is an important transport property used for modeling the diffusional mass transfer in many processes. In enhanced oil recovery from oil sands, molecular diffusion contributes to the mixing in the solvent-aided oil recovery techniques, and therefore, needs to be effectively captured for the successful modeling and performance prediction of the process. Despite the importance of diffusion coefficient in various engineering applications, there is an evident gap in the amount and quality of the diffusivity data available in the literature. This may be due to the complex nature of experimental measurements as well as the difficulties associated with analyzing the experimental data. In this study, a robust and reliable approach is developed for diffusivity measurement in systems of gaseous solvents and liquids. The developed methodology uses an analytical solution to the constant-pressure one-dimensional diffusion problem utilizing both the rate of gas dissolution and movement of the gas/liquid interface to estimate the molecular diffusivity coefficient. Moreover, a series of experimental setups have been designed, fabricated, and validated to maximize the accuracy of the experiments while satisfying the precision requirements for diffusivity measurements in systems of low soluble gases and liquids. The developed methodology was used to report the first datasets on diffusion coefficients of gaseous ethane in toluene and gaseous dimethyl ether in Athabasca bitumen and water. Also, an experimental method has been developed to measure the concentration dependency of the molecular diffusion coefficient of gases in liquids. The results indicated that the diffusion coefficient increases with the increase in test temperature. The pressure dependency, however, was explained by the effect of higher solvent concentration on the viscosity of the liquid mixture. Generally, lower viscosity at the diffusive boundary layer between gas and liquid resulted in higher diffusion coefficients. The developed methodology and the reported data have applications in the design and evaluation of solvent injection processes for heavy oil recovery.