On experimental estimation of molecular diffusion coefficient of gaseous solvents in bitumen

Measurements of the Molecular Diffusion Coefficient of Dimethyl Ether in Water at T = (313.15–373.15 K) and P = (0.69–2.76 MPa)

“…Despite the simplicity of pressure-decay methods in experimental applications, their analysis for the determination of the diffusion coefficient can often be prone to various errors. These potential errors are largely due to the mathematical challenges associated with incorporating the continuous change in the pressure-dependent thermodynamic parameters (such as gas and liquid densities, equilibrium solubilities, and viscosities) in the analysis …”

“…Moreover, the moving components of a constant-pressure experimental setup (O-rings and seals) are often susceptible to potential leaks of the highly mobile gas phase. For systems such as DME and water where the gas solubility in liquid is minute, these potential leaks can result in a significant deviation of the calculated diffusivity from its actual value . A detailed and comprehensive review on the various diffusivity measurement techniques for systems of gases and liquids has been conducted elsewhere …”

“…For systems such as DME and water where the gas solubility in liquid is minute, these potential leaks can result in a significant deviation of the calculated diffusivity from its actual value . A detailed and comprehensive review on the various diffusivity measurement techniques for systems of gases and liquids has been conducted elsewhere …”

“…These potential errors are largely due to the mathematical challenges associated with incorporating the continuous change in the pressure-dependent thermodynamic parameters (such as gas and liquid densities, equilibrium solubilities, and viscosities) in the analysis. 18 Alternatively, in the constant-pressure methods, 19−23 by their very nature, the test pressure in the entire system remains constant, therefore eliminating the uncertainties associated with the change in thermodynamic properties. While these methods are significantly less troublesome to analyze, they are often complex to implement experimentally.…”

“…For systems such as DME and water where the gas solubility in liquid is minute, these potential leaks can result in a significant deviation of the calculated diffusivity from its actual value. 18 A detailed and comprehensive review on the various diffusivity measurement techniques for systems of gases and liquids has been conducted elsewhere. 18 In this study, therefore, the principle of constant-pressure diffusivity measurement is adopted to design, fabricate, and validate an experimental setup that fulfills the accuracy and precision requirements for systems of low-soluble gases and liquids.…”