In this work, dissolution of CO2 in bulk water is simulated under isothermal pressure decay. Different boundary
conditions (BCs) including equilibrium, semi-equilibriumand non-equilibriumare examined at gas/liquid interface.
Comparison of our simulated and measured experimental data shows that the non-equilibrium BC can
predict dissolution behavior reliably. Other boundary conditions show considerable deviation between model
predictions and experimental measurements. On the other side, convective dissolution is found much more
active than diffusive mixing, so that the role of diffusive transport is overshadowed. Mass transfer coefficient is
highest at the start of dissolution and decreases with time. Results show that when convection is the active
mechanism even at late times, it interferes with diffusivity measurements and makes interpretation of diffusion
experiment results difficult both at early and later times.