Diffusion coefficients of CO₂–SO₂–water and CO₂–N₂–water systems and their impact on the CO₂ sequestration process: Molecular dynamics and dissolution process simulations

Abstract

The high cost of the CO 2 sequestration in saline aquifers is a barrier to the implementation of them. However, a large portion of the cost is invested to purify and transport the CO 2 from the flue gas stream of the emission sources. Therefore, the possibility of injecting impure CO 2 will reduce the costs strongly. The diffusion coefficient is an important factor that plays a significant role in different aspects of the process. In spite of its importance, it is got less attention due to complex experimental procedures and low range of temperature and pressure applicability in the experimental conditions. To shed light on the effects of the impurity on the diffusion coefficient of CO 2 -water systems, two types of impurities (SO 2 and N 2 ) in two levels are considered in this study through the molecular dynamics simulation approach. Simulations are done on a wide range of pressure and temperature conditions to cover a wide range of operational conditions for CO 2 sequestration projects. The outcomes of these simulations were used in the direct numerical simulations to analyze the effect of the diffusion coefficient matrix changes on the CO 2 dissolution process such as dissolution flux, the motion and shape of convective fingers, and their patterns. Results indicate that impurity has a great impact on the

Machine-Learning-Assisted Investigation of the Diffusion of Hydrogen in Brine by Performing Molecular Dynamics Simulation

“…Omrani et al used MD simulations to predict CO 2 diffusion coefficient in water/brine for a wide spectrum of pressure and temperature. They also considered multicomponent systems of CO 2 –SO 2 –water and CO 2 –N 2 –water to demonstrate the effects of impurities on CO 2 diffusion coefficient in water with implication to CO 2 sequestration . Recently, Bartolomeu and Franco studied the thermophysical properties of supercritical H 2 including the self-diffusion coefficient by MD simulation .…”

“…They also considered multicomponent systems of CO 2 −SO 2 −water and CO 2 −N 2 −water to demonstrate the effects of impurities on CO 2 diffusion coefficient in water with implication to CO 2 sequestration. 30 Recently, Bartolomeu and Franco studied the thermophysical properties of supercritical H 2 including the self-diffusion coefficient by MD simulation. 31 Overall, MD simulation is a valuable and accurate method for calculating diffusion coefficients under different conditions, especially when experiments cannot be carried out.…”