Functionalized Nanoparticles for the Dispersion of Gas Hydrates in Slurry Flow

Abstract

Gas hydrates are crystals that can form in oil and gas production. Their agglomeration in flowlines may disrupt the normal production. One current strategy of hydrate management is to inject an anti-agglomerant, a type of low-dosage hydrate inhibitor that prevents hydrate agglomeration. Concerns in the use of these chemicals include their toxicity, cost, and environmental impacts. In this study, we exploited functionalized nanoparticles in place of anti-agglomerants to produce hydrate slurry, with the potential benefit of nanoparticles to be more environmentally friendly and conveniently recyclable. We coated 256 nm spherical silica nanoparticles with different hydrophobicity and evaluated their performance for the hydrate dispersion at atmospheric and high pressure. Nanoparticles with moderate hydrophobicity stabilized oil-in-water (O/W) or water-in-oil (W/O) emulsions. Direct visualization of the cyclopentane hydrate formation from the nanoparticle-stabilized emulsions revealed different morphologies of hydrate particles depending on whether the nanoparticles prevented agglomeration. We also measured the apparent viscosity of a hydrate–nanoparticle mixture using a high-pressure rheometer. Nanoparticles with moderate hydrophobicity during hydrate formation slowed the viscosification, reduced the maximum viscosity, increased the water conversion, and ultimately helped to maintain a low steady-state viscosity. Increasing nanoparticle or salt concentrations also improved the gas hydrate dispersion. Our study demonstrated the great potential of using nanoparticles in preventing agglomeration of gas hydrates under realistic pipeline flow conditions.

Analytical Methods for Characterization of Nanomaterial Surfaces

“…Sum and coworkers used this technique to measure the contact angle of silica nanoparticles functionalized with varying concentrations of n-octadecyltrimethoxysilane (ODTMS). 96 The contact radius d and the height of protrusion h of the nanoparticles at the water−n-decane interface (Figure 6B(a)) were measured by atomic force microscopy (AFM) and SEM (Figure 6B(b)), from which contact angles were calculated. Results showed that the contact angle increased with increasing concentration of n-octadecyltrimethoxysilane (Figure 6B(c)).…”

“…Scale bars: 200 nm. (c) Measured protrusion heights h and contact angles θ. Reproduced from Zhang, X.; Gong, J.; Yang, X.; Slupe, B.; Jin, J.; Wu, N.; Sum, A. K. ACS Omega 2019 , 4 , 13496–13508 (ref ). Copyright 2019 American Chemical Society.…”

“…The trapped nanoparticle monolayer is then replicated using a poly­(dimethylsiloxane) (PDMS) elastomer, and the nanoparticles embedded in PDMS are then imaged by SEM on AFM to obtain contact angles. Sum and coworkers used this technique to measure the contact angle of silica nanoparticles functionalized with varying concentrations of n -octadecyltrimethoxysilane (ODTMS) . The contact radius d and the height of protrusion h of the nanoparticles at the water– n -decane interface (Figure B­(a)) were measured by atomic force microscopy (AFM) and SEM (Figure B­(b)), from which contact angles were calculated.…”

Molecular Insights into the Impacts of Calcite Nanoparticles on Methane Hydrate Formation

“…In another aspect of industrial applications, hydrate formation needs to be hindered in the subsea oil-gas pipelines while promoted to efficiently store and transport gases under milder conditions. To achieve these targets, several thermodynamic inhibitors, antiagglomerates, and promoters have been proposed. − One of these types is NPs. − Solid NPs have been utilized to stabilize emulsions, the so-called Pickering emulsions, and thus to disperse gas hydrates in slurry flow to prevent gas hydrate agglomeration . At the same time, it is known that heterogeneous nucleation is generally more likely to occur than homogeneous nucleation, which means that NPs in solution might induce more rapid nucleation of gas hydrates.…”

Preventing Aggregation of Hydrate Particles during Transient Operations with Vitamin E Succinate

“…The surfactant-based AAs have been studied but can cause environmental issues as a result of the toxicity nature and have drawbacks for recovering and reuse. Nowadays, the particle-type hydrate inhibitor has also been researched. − Pickering emulsions are stabilized by nanoparticles with a hydrophobic surface, which suppressed the induction time of hydrate nucleation and prevented the agglomeration of hydrate particles . In addition, numerous studies have developed biosurfactants to develop novel AAs. ,, In our previous work, the hydrate formation characteristics in the presence of vitamin E succinate (vitamin ES) were investigated to evaluate its performance in dispersing hydrate particles in a liquid hydrocarbon stream.…”