Diffusion Coefficients of CO₂ and N₂ in Water at Temperatures between 298.15 K and 423.15 K at Pressures up to 45 MPa

Abstract

We report measurements of the diffusion coefficients of CO2 and N2 in pure water at temperatures between (298.15 and 423.15) K and pressures between (15 and 45) MPa. The measurements were made by the Taylor dispersion method and have a standard relative uncertainty of 2.3 %. The results were found to be essentially independent of pressure over the range investigated and a simple relation, based on the Stokes–Einstein equation, is proposed to correlate the experimental data. Some experimental difficulties arising in the measurement of the diffusivities of slightly soluble acid-gas solutes such as CO2 in water are also discussed.

Molecular dynamics simulations of the diffusion coefficients of light n-alkanes in water over a wide range of temperature and pressure

“…This behavior is primarily driven by the change in solvent's density, which is marginal at conditions well below the critical point but becomes substantial for high pressures and temperatures. This analysis is in line with the findings of recent experimental [63,64] and computational [57] studies for gases dissolved in H 2 O.…”

Diffusion Coefficients of Carbon Dioxide in Brines Measured Using 13C Pulsed-Field Gradient Nuclear Magnetic Resonance

“…15 and 423.15) K and at pressures up to 45 MPa. 2 The results were correlated to within ± 4 % with eq 5 by making the hydrodynamic radius a weak linear function of temperature as follows:…”

“…2,3 In the absence of salts, a single diffusion coefficient fully describes the mutual diffusion of CO 2 and water in the system. When the CO 2 is dissolved in a brine, there are at least three diffusing components: CO 2 , salt, and H 2 O. Diffusion can be described in the Fickian formalism by means of the following relations where there is no net molar flux with respect to the coordinate system:…”

Atomistic Molecular Dynamics Simulations of Carbon Dioxide Diffusivity in n-Hexane, n-Decane, n-Hexadecane, Cyclohexane, and Squalane

“…[27][28] In a recent study, Cadogan et al 15 reported experimental measurements for infinitely diluted CO2 in various alkanes (n-hexane, n-heptane, n-octane, n-decane, n-dodecane, nhexadecane and squalane) obtained by the Taylor Dispersion method. 61 In the present work, we focus on simulations of the diffusion coefficients of infinitely diluted TraPPE CO2 in most of these alkanes, namely: n-hexane, n-decane, n-hexadecane, cyclohexane and squalane. The intermediate-length linear alkanes are expected to follow similar trends as the systems studied here.…”