Comparative Analysis of the Mechanisms and Kinetics of CO₂ Hydrate Formation with Sodium Dodecyl Sulfate and L-Leucine Additions under Static Conditions

Currently, to solve the key problem of increasing the efficiency of hydrate technologies for transportation, storage, and utilization of natural and anthropogenic gases in the form of gas hydrates, the use of promoter additives is proposed, among which sodium dodecyl sulfate (SDS) is considered one of the most effective and best-studied additive. However, the promoting effect of SDS does not apply to CO₂ hydrate formation. Amino acids are a new class of gas hydrate formation promoters that have recently been actively studied. We have studied the effect of L-leucine amino acid on the growth kinetics and morphology of CO₂ hydrates. A 0.5 wt % L-leucine addition increases the rate of hydrate formation and the conversion of water to hydrate dozens of times. It was established that the hydrate film formed at the gas–liquid interface on the side of the gas phase is permeable for liquid, while on the side of the liquid phase, the formation of an impermeable hydrate film is inhibited by the L-leucine additive. This combined effect of L-leucine on the hydrate film morphology at the gas–liquid interface leads to the formation of porous hydrate deposits on the side surface of the reactor and to growth of CO₂ hydrates in the gas phase by the capillary mechanism.