Carbon dioxide sequestration as hydrates in clayey-sandy sediments: Experiments and modeling approach

Carbon capture and sequestration (CCS) is the key to a low carbon transition model applicable to attain the Net-Zero targets. In this direction, the hydrate-based CO2 sequestration (HBCS) approach has gained significant attention due to its high storage capacity and long-term stability. The current work evaluates the CO2 hydrate formation kinetics and storage capacity in clayey-sandy sediments and develops a chemical potential-based kinetic model for porous hydrate sediments. Experiments are performed in a high-pressure reactor mimicking the subsea sediment conditions. Multiple silica sand sediments with various clay content (2–8 wt%) are used as a porous media, and saline water of 3.5 wt% salinity is used as a substitute for seawater. For a successful deployment of HBCS technology, the effect of the following parameters is investigated for CO2 hydrate formation kinetics and storage capability: impact of clay content in sediment; salinity, sediment’s particle size; water saturation of the sediments; and hydrate promoter (L-Tryptophan). Besides the close prediction of the conversion kinetics of water-CO2 to CO2 hydrates in the aforementioned distinctive operating environments, the proposed kinetic model offers its generalized potential. This work offers important insights into the deployment of HBCS in subsea clayey-sandy sediments available in the Krishna-Godavari (KG) Basin of India.