Professor Yutaek Seo from the Division of Ocean Systems Engineering and postdoctoral scholar Kyuchul Shin revealed a mechanism of how methanol, previously recognized as antifreeze, can be incorporated into clathrate hydrates, ice-like molecular cages, by taking the dual roles as promoter and inhibitor in hydrate formation under certain conditions.
Methanol usually suppresses or delays the formation of icy phases of aqueous solutions. Therefore, it has been used to prevent clathrate hydrates from blocking oil and gas pipelines. Although vigorous research of hydrate inhibition was conducted in oil and gas industries as a part of gas-pipeline flow assurance program, there has been little to no direct evidence till now that methanol participates in the hydrate formation.
The research team demonstrated that methanol is incorporated into the hydrate lattice along with other guest molecules at temperatures near 274 K and that the amount and species with the included methanol depends on the method used to prepare the samples using X-ray diffraction and nuclear magnetic resonance. Furthermore, they successfully showed that the presence of methanol in fact accelerates hydrate formation at temperatures characteristic of icy planetary bodies. The results will have significant implications in the industry, as it can provide an explanation for the causes of hydrate formation accidents, which were previously unknown.
Professor Seo said, “The results are truly groundbreaking as they refute the original hypothesis. Methanol’s dual role may be relevant to its roles in planetary environments as well- Saturn’s icy moons Titan and Enceladus for instance. It can work as antifreeze, preventing Titan’s primordial subsurface aqueous ocean from freezing, and at the same time, it can accelerate hydrate formation, perhaps modifying the atmosphere. We are going to continue our research with a follow-up study since it is likely to start a ripple effect throughout many areas.”
The research was conducted in cooperation with the National Research Council, the Canadian government’s premier organization for research and development. The results were published in the May 21 issue of the world-renowned journal Proceedings of the National Academy of Sciences of the United States of America.