Effect of Hydrophobic Silica Nanoparticles on the Kinetics of Methane Hydrate Formation in Water-in-Oil Emulsions

Abstract

This study addresses the effect of hydrophobic silica nanoparticles (SiNPs) on methane hydrate formation in water-in-decane emulsions. Even though the new concept of hydrophobic particle inhibitors has been proposed in the flat interface of oil and bulk water phases, the mechanism of the particle inhibition has not been investigated for a hydrate-forming emulsion system. Numerous experiments with various amounts of SiNPs applied to water-in-decane emulsions and different temperature and pressure profiles have verified how the nanoparticles interact at the interface for hydrate inhibition or promotion. At lower concentrations of SiNPs, they act as a hydrate inhibitor. However, as the amount of SiNPs increases beyond a certain concentration (0.5 wt %), the formation rate anomalously increases because the oil film of the emulsions containing methane becomes thicker with the increasing amount of SiNPs, and water molecules form capillary bridges along the nanoparticle alignment. Our experimental results and suggested mechanisms provide insights into the interfacial behaviors of SiNPs for preventing hydrate formation in water-in-oil emulsions.

Self-Organized Colloids Thermodynamically Weaken the Effect of Salt on Methane Hydrate Formation

“…Therefore, the colloids in our case are considered to be stable. In an emulsion system, the hydrophobic nanoparticles can be adsorbed at the water-in-oil interface; the resulting interface effect increases the resistance of gas transmission during the formation of hydrates, preventing the aggregation of hydrate particles . However, the situation is different in our non-emulsified system.…”

“…In an emulsion system, the hydrophobic nanoparticles can be adsorbed at the water-in-oil interface; the resulting interface effect increases the resistance of gas transmission during the formation of hydrates, preventing the aggregation of hydrate particles. 59 However, the situation is different in our non-emulsified system. The inhibition of gas mass transfer and the particle agglomeration might not be a major concern.…”

Interfacial study of clathrates confined in reversed silica pores

“…24 However, a point of agreement between experimental and theoretical studies is the fact that hydrophobic silica surfaces are more effective in clathrate promotion. 25,26 In this sense, it seems an interesting approach to direct the formation of clathrates in nanoporous silica materials by graing the silica surface with hydrophobic moieties, such as alkyl groups, at the SiO 2 surface. This approach is employed in the synthesis of well-known amorphous reversed silica materials, widely used in chromatography separation.…”

Molecular Dynamics Simulations of Hydrophobic Nanoparticle Effects on Gas Hydrate Formation

“…When a hydrate slurry, which greatly reduces the subcooling temperature, is injected into the particle-stabilized water–oil interface in the bulk phase, the hydrate formation is not promoted. This suppression of nucleation seeds was observed in a gaseous guest molecule, propane, as well as in liquid hydrate formers such as cyclopentane. , In addition, in a Pickering emulsion system, the induction time of hydrate nucleation and the dispersity between hydrate particles were increased until a monolayer of nanoparticles was formed . Nanoparticles thus not only interfered with the interactions between hydrate particles and bulk phases but also played a role similar to KHIs and AAs in hydrate-forming liquids with small quantity.…”