Volume-Dependent Adhesion Behaviors Between Clathrate Hydrates and Water

Clathrate hydrates are crystalline compounds in which guest molecules such as methane, ethane, carbon dioxide, cyclopentane (CP), etc. are entrapped in host water cages formed by the hydrogen-bonded network of water molecules. During the extraction process of oil and gas, the existence of water and gas can lead to the formation of hydrate inside the pipeline. Hydrate particles can be aggregated/agglomerated down the pipeline. The continuous growth of hydrate particles can lead to a shutdown of the production due to the pipeline blockage. Therefore, the interfacial dynamic behavior needs to be identified to understand the adhesion between hydrate particles and water droplets in the pipeline.

Here, we investigated the volume-dependent adhesion behaviors between cyclopentane (CP) hydrate and solution droplet in a CP/n-decane oil mixture. Three to five times of precise contact force measurements are obtained from 100 to 600 μL of solution droplet by using the z-directional microbalance. In both pure water and surfactant solution system, there is a transition volume over certain level of solution droplet. In addition, we also visually observed the abnormal variations of capillary bridge between CP hydrate and solution droplet through the optical microscope.