Gas hydrate inhibition by urea and its blends with vinyl lactam polymer: Paving the way to green hybrid inhibitors

被引：0

作者：

Semenov, Anton P. ^{[1
]}

Mendgaziev, Rais I. ^{[1
]}

Stoporev, Andrey S. ^{[1
]}

Tulegenov, Timur B. ^{[1
]}

Lednev, Daniil A. ^{[1
]}

Voronin, Denis V. ^{[1
]}

Vinokurov, Vladimir A. ^{[1
]}

机构：

[1] Gubkin University, Department of Physical and Colloid Chemistry, 65, Leninsky Prospekt, Building 1, Moscow

来源：

Journal of Molecular Liquids | 2024年 / 414卷

关键词：

Hydrate growth; Kinetic hydrate inhibitor; Methane-propane gas mixture; Nucleation rate; Urea;

D O I：

10.1016/j.molliq.2024.126136

中图分类号：

学科分类号：

摘要：

Urea is an environmentally benign substance considered a promising gas hydrate inhibitor in flow assurance. Nevertheless, its effect on gas hydrate formation kinetics remains poorly understood. This study investigates the impact of urea and hybrid urea/polymer KHI samples on the nucleation and growth kinetics of sII natural gas hydrates. Hydrate formation was observed at a lower onset temperature with increasing urea and polymer concentration. The nucleation of sII hydrate in aqueous urea solutions occurred at a higher subcooling (7.50 ± 0.58 K at 30 mass%) than in pure water (5.17 ± 0.69 K). These findings indicate that urea acts as a nucleation inhibitor of sII hydrates, although its capacity is not as potent as that of polymer KHI. The analysis of the hydrate nucleation probability distributions revealed that the sII hydrate nucleation rate exhibited a significant decline, approximately one order of magnitude, at subcooling of 5.3–6 K for 20 mass% urea compared to water. A similar behavior was noticed in an aqueous solution of polymer KHI. Urea has succeeded in providing a total benefit of up to 10 K in hydrate onset temperature due to a shift in the hydrate stability zone and nucleation retardation. Consequently, urea is a green dual-acting anti-hydrate chemical that inhibits the formation of sII hydrates by thermodynamic and kinetic mechanisms. Besides, adding 10 mass% urea increases the cloud point temperature of vinyl lactam polymer Luvicap 55W by 14 K. Urea is an additive that considerably augments the stability of the polymer in aqueous solutions at elevated temperatures. These findings make urea an effective and environmentally friendly top-up inhibitor that significantly enhances the anti-hydrate properties of polymer KHI. © 2024 Elsevier B.V.

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