Non-Einsteinian Viscosity Behavior in Plasma-Functionalized Graphene Nanoflake Nanofluids and their Effect on the Dynamic Viscosity of Methane Hydrate Systems

TL;DR

This study investigates how plasma-functionalized graphene nanoflakes (O-GNFs) influence the viscosity behavior of methane hydrate systems, revealing faster viscosity development and potential benefits for hydrate technology applications.

Contribution

It demonstrates that O-GNFs can accelerate viscosity changes and reduce the energy required for hydrate formation, offering novel insights into nanofluid effects on hydrate systems.

Findings

O-GNFs do not affect water's pressure-viscosity relationship except at 10 ppm.

Hydrate phase transition remains unchanged with O-GNF presence.

Viscosity reaches desired levels faster with O-GNFs, especially at 1 ppm.

Abstract

Water's viscosity dependence on pressure was also not affected by O-GNFs, except at 10 ppm, where the shuttle effect may have increased the presence of hydrophobic methane bubbles in the solution. Under high pressure, the relative viscosity of the system remained non-Einsteinian at all temperatures except 2C. This may have been because the density anomaly of water was shifted to a colder temperature as the hydrogen bonding network was weaker. The phase transition from liquid to hydrate was identical to that of pure water, indicating that the presence of different stages of growth was not affected by the presence of O-GNF. However, the times to reach a maximum viscosity were faster in O-GNF systems compared to pure water. This said, the hydrate formation limitations inherent to the measurement system were not overcome by the presence of O-GNFs. The times to application-relevant viscosity values were maximized in the 1 ppm system at 49.75 % (200 mPa.s) and 31.93 % (500 mPa.s) faster than the baseline. Therefore, the presence of O-GNFs allowed for shorter times to desired viscosities and at lower driving forces than the baseline, improving the viability of the hydrate technologies to which they can be added.