High-resolution performance tests of nucleation and growth suppression by two kinetic hydrate inhibitors

• Published in: Chemical engineering science 2021-11, Vol.244, p.116776, Article 116776
• Main Authors: Barwood, Mark T.J., Metaxas, Peter J., Lim, Vincent W.S., Johns, Michael L., Aman, Zachary M., May, Eric F.
• Format: Article
• Language: English
• Subjects: Gamma distribution; Gas hydrates; Induction time; Kinetic hydrate inhibitors; Nucleation
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2021.116776

•Performance of two KHIs tested via induction times and hydrate growth rates.•KHI performance can be subcooling dependent.•Data matches previous result that KHIs yield gamma-distributed induction times.•Gamma distribution fits can be used to estimate formation risk for an application. The development of kinetic hydrate inhibitor (KHI) performance rankings is essential for these chemicals’ implementation within risk-based hydrate management strategies. Here, we obtain high resolution induction time distributions and growth rate measurements with a high pressure, stirred, automated lag time apparatus (HPS-ALTA) to make rigorous comparisons between two industrial KHIs (Inhibex 501 and 713). These comparisons reveal performance rankings can be subcooling dependent, and that growth rate alone is insufficient for accurate screening. Application of a Classical Nucleation Theory (CNT) based model to these results suggests that nucleation in systems dosed with Inhibex 501 and 713 respectively occurs on 7 and 700 times as many sites as compared to KHI-free systems, while the nucleation work required at these sites is increased by a factor of 9 and 28. When combined with gamma distributions and fluid residence times, these measurements can help inform the operational risk assessment of a hydrate blockage.