Influence of Model Oil with Surfactants and Amphiphilic Polymers on Cyclopentane Hydrate Adhesion Forces

Abstract

Adhesion forces between cyclopentane hydrate particles were measured at atmospheric pressure and 3.2 °C using an improved micromechanical force apparatus. Because of the complexity of crude oil systems, a series of model oils was prepared by adding surface-active components to 200 cP mineral oil as analogues to crude oil systems. The addition of 1 wt % sorbitan monooleate (Span80, a commercial anti-agglomerant), 1 wt % polypropylene glycol (an amphiphilic polymer), and 0.6 wt % commercial naphthenic acid mixture, separately, to a mineral oil and cyclopentane continuous phase, reduced the average interparticle hydrate adhesion force by 37, 65, and 80%, respectively, compared to pure mineral oil and cyclopentane. The 95% confidence bounds of the Span80 and mineral oil data points overlap; therefore, we cannot conclude that Span80 was effective at reducing the adhesion force between hydrate particles. These results indicate that model amphiphilic polymers and commercial naphthenic acid mixtures may be surface-active on the hydrate particle, drastically reducing the agglomeration tendency between hydrate particles; naphthenic acids are found to be the most effective at lowering the adhesive force between particles. The structure of the additive plays a role in determining the extent of surface activity and effectiveness. Compounds with small hydrophilic groups can more efficiently adsorb to the hydrate surface, while additives that induce morphological changes to the hydrate surface may cause non-uniform growth and are more effective in preventing hydrate agglomeration.

Can cyclopentane hydrate formation be used to screen the performance of surfactants as LDHI anti-agglomerants at atmospheric pressure?

“…The surfactant should have good adsorption on the hydrate particle surfaces. (Aman et al, 2010). This is the AA mechanism by which all commercial cationic AAs operate.…”

A comparison of the rheological behavior of hydrate forming emulsions stabilized using either solid particles or a surfactant

“…Hydrate forming emulsions formed 37 using solid particles had a higher viscosity than emulsions formed using surfactant. 38 Ó 2016 Published by Elsevier Ltd. Flow assurance problems are a major concern to offshore 44 energy development [1]. Some of the flow assurance problems 45 include formation of hydrates, waxes, asphaltenes, and corrosion 46 of pipelines.…”

Effects of SDS and SDBS on CO2Hydrate Formation, Induction Time, Storage Capacity and Stability at 274.15 K and 5.0 MPa

“…A significant decrease of surface tension was also resulted in water with stirring since the stirring shear decreased, forming porous hydrate and growing rapidly in the vessel wall. Another reason was that the surfactant may decrease the adhesion force between the two hydrate particles and prevent the agglomeration of gas hydrates, which resulted in a goodmixing of water and liquid CO 2 phase and then the promotion of hydrate formation . The fluctuations in the temperature‐time and pressure‐time profiles of SDBS are similar to those of SDS, which means demonstratesno difference in the equilibriumprocess of CO 2 hydrate formation inboth solutions.…”

“…Another reason was that the surfactant may decrease the adhesion force between the two hydrate particles and prevent the agglomeration of gas hydrates, which resulted in a goodmixing of water and liquid CO 2 phase and then the promotion of hydrate formation. [13,14] The fluctuations in the temperature-time and pressure-time profiles of SDBS are similar to those of SDS, which means demonstratesno difference in the equilibriumprocess of CO 2 hydrate formation inboth solutions. After the rapid growth of hydrate nuclei, the pressure drops slowly and attains stable.…”