Storage of greenhouse gases in the form of gas hydrates is attractive and is being pursued rigorously in recent times. However, slow formation rate and inefficient water to hydrate conversion are the main hindering factors. In this report, we examine the role of two amino acids (0.5 wt%), l-methionine (l-met) and l-phenylalanine (l-phe) on the formation of gas hydrates using methane (CH₄), carbon dioxide (CO₂) and their mixtures as guest molecules. Experiments are conducted under non-stirred and isochoric configurations. The hydrate conversion efficiency of both amino acids is identical for hydrates formed with CH₄ and mixture of (CO₂+CH₄). However, the hydrate conversion is significantly less in CO₂ hydrates in l-phe system. Addition of amino acids to the water dramatically improved the kinetics of hydrate formation and 90% of maximum gas uptake in hydrate phase occurred in less than an hour. The water to hydrate conversion is also very efficient (>85%) in the presence of amino acids. Therefore, the amino acids containing systems are suitable for storing both CH₄ and CO₂ gases. The gas hydrates were characterised using powder x-ray diffraction (XRD) and Raman spectroscopic measurements. These measurements indicate the formation of sI hydrates and encasing of gas molecules as guests.

Gas hydrate, a solid transformed from an ensemble of water and gaseous molecules under suitable thermodynamic conditions, is present in marine and permafrost strata. The ability of methane hydrates to exist outside of its standard stability zone is vital in many aspects, such as its utility in gas storage and transportation, hydrate-related climate changes and gas reservoirs on the planet. A systematic study on the stability of methane hydrates divulges that the gas uptake decreased by about 10% by increasing the NaCl content to 5.0 wt%. The hydrate formation kinetic is relatively slower in a system with higher NaCl. The self-preservation temperature window for hydrate systems with NaCl 1.5, 3.0 and 5.0 wt% dramatically shifted to a lower temperature (252 K), while it remained around 270 K for NaCl 0.0 and 0.5 wt%. Based on powder x-ray diffraction and micro-Raman spectroscopic studies, the presence of hydrohalite (NaCl·2H₂O) phase was identified along with the usual hydrate and ice phases. The eutectic melting of this mixture is responsible for shifting the hydrate stability to 252 K. A systematic lattice expansion of cubic phase infers the interaction between NaCl and water molecules of hydrate cages.

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.