Effects of Soil Leachate on CO ₂ Hydrate Formation: A Case Study of the Beiluhe Region

The current form of carbon emissions is severe, and geological storage of CO2 in the form of hydrates has become an important research direction. This study focuses on the potential CO2 sequestration area in the Beiluhe region, exploring the influence of the soil leachate system on the formation process of CO2 hydrates in the region and investigating the effect of adding l-methionine (l-Met). The experiment was conducted in a high-pressure reactor (3 MPa, 274.85 K), using leachate with different leaching durations (0.5, 1, 2, 4, and 8 h) from the Beiluhe region, and different concentrations of l-Met (0, 0.1, and 0.2 wt %) were added to evaluate the formation of CO2 hydrates. Comparing the pure water system with the leachate system, it was found that leachate has a significant promoting effect on induction time and a significant inhibitory effect on gas consumption and formation rate. Adding 0.1 wt % l-Met has a significant promoting effect, reducing the induction time by up to 35.3% and increasing the average production rate by up to 8.69%. Adding 0.2 wt % l-Met has a significant inhibitory effect, increasing the induction time by up to 394%. The experimental results indicate that adding 0.1 wt % l-Met to the leachate system can promote the process, while the addition of 0.2 wt % l-Met has an inhibitory effect. It is feasible to add accelerators in geological storage, but attention should be paid to the selection of concentration.