Modeling of ex-situ dissolution for geologic sequestration of carbon dioxide in aquifers

Underground carbon dioxide (CO2) sequestration is considered to be one of the main methods to mitigate greenhouse gas (GHG) emissions. In this technology, pure CO2 is injected into an underground geological formation and since it is less dense than residual fluids, there is always a risk of leakage to the surface. To increase security of underground CO2 disposal, ex-situ dissolution can be implemented. When CO2 is dissolved in brine before injection, it significantly reduces the risks of leakage. In this approach, pure CO2 is dissolved on the surface before injection. Surface dissolution could be achieved in a pipeline operating under the pressure of a target aquifer into which the CO2 is injected. In a pipeline, CO2 droplets are dissolved being dispersed in a brine turbulent flow. In this paper, a comprehensive model of droplet dissolution along a pipeline is presented. The model accounts for droplet breakup and coalescence processes and is validated against available experimental data.