Experimental Investigation on the Interaction Forces between Clathrate Hydrate Particles in the Presence of a Water Bridge

The agglomeration of hydrate particles is one of the main causes of hydrate accumulation or bedding in oil and gas pipelines. The unconverted water droplets in the system play a crucial role in hydrate particle agglomeration. In this study, a novel technique was developed to directly measure the interaction forces between cyclopentane hydrate particles with a water bridge between them using a micromechanical force apparatus. On the basis of the developed method, the interaction forces at different temperatures and water bridge volumes and the effects of mineral oil were experimentally studied. At a low subcooling level of 1.7 degrees C, the contact areas and adhesion forces between the hydrate particles and water droplets increased with the increase in the water droplet volume. For the case of a higher subcooling level of 6.2 degrees C, rapid hydrate formation between the bridging water droplets prevented the hydrate particles from being effectively wetted, resulting in a small contact area. There was no clear relationship between the contact area/adhesion force and the water droplet volume. The hydrates formed on the water bridge could dramatically strengthen the adhesion force, while the addition of mineral oil in cyclopentane could retard the water droplets from converting into hydrates, consequently decreasing the adhesion force. The measured adhesion forces between the hydrate particles and water droplets may provide further insight into the hydrate agglomeration process.