Influence of Amino Acids on CO2 Hydrate Formation Kinetics in Silica Sand: An Experimental Study

Hydrates are regarded as a highly promising medium for energy gas and greenhouse gas storage due to their high gas storage capacity and relatively mild thermodynamic stability conditions. In recent years, hydrate-based CO2 sequestration technology has attracted widespread attention for its potential applications in carbon capture and storage (CCS). However, the practical implementation of this technology is limited by slow hydrate formation kinetics, manifested as long induction periods, low formation rates, and insufficient gas conversion efficiency. Amino acids, as environmentally friendly hydrate promoters, show promising application potential in accelerating hydrate nucleation and growth processes. To address this, a simulated submarine sediment system was constructed using a 3.5 wt% NaCl solution and quartz sand. The formation kinetics of CO2 hydrates under different concentrations of amino acids (L-methionine and L-leucine) were systematically investigated, with a focus on examining key parameters including hydrate yield, induction time, and water conversion ratio. The results revealed that L-methionine showed no significant promotion effect on CO2 hydrate formation, while L-leucine even inhibited hydrate yield. These findings indicate that neither L-methionine nor L-leucine are ideal candidate additives for CO2 hydrate sequestration. This study can provide a theoretical basis and technical reference for efficient CO2 sequestration via promoted hydrate methods.