A clathrate (or gas) hydrate is a crystal involving water molecules that form a cage, which encapsulates a larger molecule, most commonly a gas such as methane or ethane. These hydrates form under conditions of high pressure and low temperature found in natural gas and oil flowlines. Methane hydrate formation in oil pipelines can build up and create clogs, which can lead to explosions due to gas ignition. Oil spills are another environmental and economic consequence that can stem from methane hydrate accumulation. Kinetic hydrate inhibitors (KHIs) are mostly polymers that increase the time it takes for hydrates to form as well as inhibit the growth of formed hydrates. Kinetic inhibitors of gas hydrates are used in industry to limit the growth of hydrates in pipelines, but the mechanism by which KHIs work is poorly understood. Our research focuses on developing new ways to grow hydrates in the laboratory and investigating the mechanism by which kinetic inhibitors interact with gas hydrates. Tetrahydrofuran (THF) hydrates are used as a model to investigate the interaction between inhibitors and hydrate surfaces, as THF hydrates are stable at atmospheric pressure and at about 3°C, which is simpler to work with. Previously, THF hydrates were grown on a copper or glass cold finger in order to study interactions with inhibitors at a macroscopic scale. However, with this methodology, it is difficult to control hydrate growth, temperature, and quantitatively determine the capacity of inhibition. In our study, we created a method of growing micron-sized THF hydrates in a temperature-controlled environment under a microscope, allowing us to isolate single crystals. We have been able to compare the inhibition activity of known kinetic hydrate inhibitors, and identify new inhibitors. We continue to study the mechanism of interaction between the inhibitors and the hydrate surface. These findings will effectively contribute to the demands of preventing environmental pollution, and lowering the costs of gas and oil.

New methods of growing clathrate hydrates and testing kinetic inhibitors

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.