Chemically Enhanced Convective Dissolution of CO_{2}.

Area of Science:

• Geochemistry
• Fluid Dynamics
• Carbon Capture and Storage

Background:

• Convective dissolution is a key mechanism for geological storage of carbon dioxide (CO_{2}).
• This process involves CO_{2} dissolving into an aqueous solution, forming a denser liquid that sinks, driving further dissolution.
• Chemical reactions within the aqueous phase can potentially enhance the rate of convective dissolution.

Purpose of the Study:

• To experimentally investigate the impact of chemical reactions on CO_{2} convective dissolution.
• To quantify the enhancement in plume velocity due to chemical reactions.
• To validate a model predicting the observed effects without adjustable parameters.

Main Methods:

• Experiments were conducted in a cylindrical container filled with a sodium hydroxide (NaOH) solution.
• Supercritical or gaseous CO_{2} was introduced to initiate convective dissolution.
• Measurements of plume velocity were performed under varying conditions, including the presence and absence of NaOH.

Main Results:

• The presence of sodium hydroxide (NaOH) significantly enhanced the convective dissolution process.
• Experimental measurements showed a tenfold increase in plume velocity compared to dissolution in a solution without NaOH.
• A predictive model accurately reproduced the experimental results without requiring parameter adjustments.

Conclusions:

• Chemical reactions, specifically with NaOH, dramatically accelerate CO_{2} convective dissolution.
• This finding has significant implications for improving the efficiency and safety of geological CO_{2} storage.
• The validated model provides a reliable tool for predicting CO_{2} behavior in geological formations.