High pressure nuclear magnetic resonance measurement of spin–lattice relaxation and self-diffusion in carbon dioxide

Abstract

Spin–lattice relaxation time and self-diffusion coefficient in 13CO2 have been measured on the four isotherms 0, 25, 50, and 75 °C at pressures ranging from 10 to 500 bar. The governing relaxation mechanism in this range is shown to be spin–rotation relaxation. Low pressure T1 data are adequately described by Gordon’s theory, while high pressure T1 data agree semiquantitatively with the diffusion model proposed by Hubbard. The low density self-diffusion coefficient behavior is in agreement with the kinetic theory of the dilute gas phase. Strong divergence from Enskog theory is observed in the dense gas and liquid phases. The hard-sphere theory predicts the self-diffusion coefficient within ±2% at densities above 1.5 ρc. The simple hydrodynamic theory predicts the self-diffusion coefficient within ±5% at densities above 1.5 ρc.

Self-Diffusion and Binary Maxwell–Stefan Diffusion Coefficients of Quadrupolar Real Fluids from Molecular Simulation

“…The uncertainty of the present self-diffusion data is less than 1%; numerical values for all fluids are given in Table II. Figure 1 shows the results for the product of density and self-diffusion coefficient of F 2 , N 2 , CO 2 , and CS 2 compared to experimental data [35][36][37][38]. For F 2 and N 2 , the considered state points correspond to the saturated liquid, for which experimental densities were taken from Refs.…”

“…Self-diffusion coefficients of fluorine, nitrogen, carbon dioxide, and carbon disulfide as predicted by molecular simulation in comparison to experimental data[35][36][37][38].F 2 (saturated liquid, T = 54 − 105 K): exp., sim. ; N 2 (saturated liquid, T = 77 − 93 K): exp., .s im.…”

Prediction of carbon dioxide permeability in carbon slit pores

“…The self-diffusivity of 3-CO 2 -NGU (about 12 × 10 −9 m 2 /s) at infinite dilution (f ≈ 0) is higher than that of 3-CO 2 -HAR (about 8 × 10 −9 m 2 /s [10]) obtained from EMD at T = 303 K in a silicalite having pore size of about 0.54 nm. It was reported that the self-diffusion coefficient of CO 2 was 1.94 × 10 −9 m 2 /s in aqueous solution at T = 298 K [40], while it was about 0.9 × 10 −6 m 2 /s in gas phase at T = 298 K and P = 10 bar [41]. Therefore, the diffusivity in the confined slit pore is closer to that of aqueous solution, which was also recognized by Zhou and Table 2 LJ model parameters of CO2 molecules and the adsorption density error between 3-CO2-NGU and the others.…”

NMR studies of carbon dioxide and methane self-diffusion in ZIF-8 at elevated gas pressures

“…The relaxation times in the gas phase above the ZIF-8 bed were compared to known pressure dependent CO 2 gas phase relaxation times published in Etesse et al (1992).…”