Tuning CO ₂ Hydrate Kinetics and Storage Capacity via Particle Surface Functionalities: Implications for Carbon Capture and Sequestration

Large-scale hydrate-based carbon capture and sequestration (HBCCS) through hydrates in a subsea environment will play a pivotal role in combating global warming. The role of clay/particles in hydrate kinetics is crucial and not widely investigated, especially in the submicrometer size particle scale for HBCCS. The impact of submicrometer particles (SmPs: >1000 nm) and their surface functionalities on gas hydrate kinetics in larger liter-scale reactors have been investigated. Investigations have been carried out using sodium dodecyl sulfate (SDS) and SiO2 particles with different surface features dispersed in seawater at ∼276 K and ∼4.5 MPa injection pressure. All silica particles demonstrate an inhibitory effect on hydrate induction time; however, the degree of the increase in induction time depends on the hydrophilicity of particles. In this study, both conventional (Vg = constant) and modified approach (Vg = variable) were compared and a nearly 5–7.6% increase in gas uptake has been observed with the modified approach incorporating volume change effect owing to hydrate volume change in comparison to the traditional approach. The CO2-philic functionalized silica particle system demonstrates ∼5.4% and 88.6% increase in gas uptake compared to seawater (SW) + SDS and SW systems; however, it has a ∼1.12 times slower initial hydrate formation rate than SW + SDS but a ∼4.6 times faster initial hydrate formation rate than the seawater system. The functionalized CO2-philic silica system with high surface area and porosity adsorbed and slowly released CO2 through micro/mesopores, yielding higher gas uptake at slower rates. Fumed silica particles achieved higher hydrate formation rates due to their moderate surface area and chain-like aggregates creating abundant heterogeneous nucleation sites, but their high hydrophilicity reduced overall gas uptake.