Interfacial Adhesion Forces of Hydrate Particles in the Presence of Hydrate Inhibitors

Abstract

Hydrate inhibitors are traditionally utilized to prevent hydrate plugging. In this study, the adhesion forces of cyclopentane (CP) hydrates with thermodynamic inhibitors (ethanol, urea, and NaCl) and anti-agglomerant inhibitors [sorbitan monooleate (Span 80) and lecithin] were measured to understand the effects of hydrate inhibitors on the adhesion forces of hydrates. It was found that the thermodynamic inhibitors increased the early hydrate interparticle adhesion force due to the enhanced liquid bridge force. However, the liquid bridge acted as a lubricant layer to prevent the irreversible agglomeration of hydrate after long-term contact. The hydrate adhesion forces decreased by 90.5−93.0% and 76.6−92.7% with an increase in the concentration of Span 80 and lecithin, respectively, from 0.1 to 1 wt %. Both rough morphology and low interfacial tension contributed to the adhesion force decrease of hydrate after the addition of anti-agglomerant inhibitors. The results may be helpful for understanding the mechanism of influence and quantifying the impact of hydrate inhibitors on hydrate interparticle adhesion force.

Multifunctional Amphiphobic Coating toward Ultralow Interfacial Adhesion of Hydrates

“…The nucleation and adhesion of the TBAB hydrate on the surface of the substrates were measured using a micromechanical force (MMF) apparatus, and a photograph of the MMF apparatus is shown in Figure S3. Details of the experimental operation platform were introduced in a previous work of our group. , A drop of 30 wt % TBAB solution was suspended at the end of a glass fiber, which was frozen in liquid nitrogen and then placed in an isooctane bath at −5 °C. The substrate was then moved by a controlled automatic manipulator, and a contact force of 0.1 μN was applied to the hydrate particle.…”

“…Details of the experimental operation platform were introduced in a previous work of our group. 3,20 A drop of 30 wt % TBAB solution was suspended at the end of a glass fiber, which was frozen in liquid nitrogen and then placed in an isooctane bath at −5 °C. The substrate was then moved by a controlled automatic manipulator, and a contact force of 0.1 μN was applied to the hydrate particle.…”

Flow Assurance of Hydrate Risk in Natural Gas/Oil Transportation: State-of-the-Art and Future Challenges

“…On the basis of the macroscopic model of the hydrate deposition blockage on the surface of the pipeline wall, it is essential to further explore the mechanism of aggregation between hydrate particles and the adhesion-inducing factors of hydrate deposition on the pipeline wall from a microscopic perspective. Therefore, the interaction between the particles in different conditions has been studied by the high-pressure micromechanical force (HP-MMF) system. − As shown in Figure a, direct observations from the HP-MMF indicated the appearance of asphaltene precipitates interacting with the gas hydrate particles to produce an asphaltene–hydrate mixed agglomerate . A new HP-MMF method has been introduced, which can enable representative sampling and evaluation of the effect of crude oil samples on the cohesive force between two gas hydrate particles.…”

Molecular Insights into the Dual Promotion–Inhibition Effects of NaCl at Various Concentrations on the CO2 Hydrate Growth: A Molecular Simulation Study

“…The emissions of CO 2 have increased by about 90% since 1970, and the excessive release of CO 2 causes a serious greenhouse effect. − Gas hydrates are ice-like solids formed by the cage-like structure constructed by water molecules and the trapped nonpolar gas molecules at appropriate temperature and pressure conditions. − The CO 2 hydrates, possessing great CO 2 storage capacity, can be stored in marine environments at medium to deeper depths . Compared to conventional geological storage of CO 2 , storing CO 2 in the form of hydrates in the ocean has a larger reserve, which may be a potential way to mitigate global warming. − …”