Enrichment of gas storage in clathrate hydrates by optimizing the molar liquid water–gas ratio

Abstract

Natural gas (NG) is considered a modern source of energy. Gas hydrates are anticipated to be an alternative method for gas storage and transportation applications. The process must be handy, rapid, and proficient for scale-up. In the present study, methane (CH₄) and carbon dioxide (CO₂) hydrates are synthesized by varying the guest (gas) to host (water) volume. The experiments are performed in a non-stirred system. The results specify that the maximum storage capacity is achieved when the molar liquid water–gas ratio is about 4.08 and 8.25 for CH₄ and CO₂ hydrates. At the optimal water–gas ratios, the total CH₄ and CO₂ gas uptake capacity is about 14.3 ± 0.4 and 9.1 ± 0.4 liters at standard temperature and pressure (STP) conditions. The gas uptake gradually increases with the solution volume and abruptly falls after a threshold point. The hydrate grows across the reactor's metal surface; when the process fully covers the surface, the growth continues horizontally (increase in thickness). With varying the liquid water–gas ratio (low to high), the formation kinetics (t₉₀) is delayed. The hydrate growth rate gradually decreases and does not significantly influence the hydrate formation temperatures. Optimizing the molar liquid water–gas ratio yields a high gas storage capacity and faster process kinetics.