Kinetic study of amino acids inhibition potential of Glycine and l-leucine on the ethane hydrate formation

Abstract

The experimental and theoretical investigations on ethane hydrate formation were performed for both pure water and amino acid aqueous solutions containing Glycine and l-leucine inhibitors. Herein, a kinetics model based on the thermodynamic natural path was proposed to describe the hydrate crystal growth in a stirred batch reactor at the constant volume. To explore the relationship between the kind and concentration of inhibitors and the rate of hydrate formation, the experiments were conducted at temperature of 277 K under the selective pressure as a driving force in different concentrations of Glycine and l-leucine (range: 0.05, 0.1, 0.5, 1, 2 and 3 weight percentage). The results measured based on the induction times and the kinetic trends of hydrate formation indicate that amino acids with lower hydrophobicity are better than others to delay the nucleation stage and reduce the growth rate. So that Glycine is introduced as a stronger inhibitor than l-leucine due to lower hydrophobicity. Moreover, the parameters of kinetic model, Ar/RT and tK, were obtained for each experiment in the presence of amino acids. The good agreement between predicted results and the experimental data indicated that this model is able to predict the ethane hydrate formation.