Carolyn A. Koh
Associate Professor
Research Description
Natural gas hydrates are crystalline inclusion compounds, which are capable of hosting small molecules inside the cages of a hydrogen-bonded water framework. Hydrates of natural gas present a potential hazard to the oil and gas industries when they form in subsea oil/gas flowlines. On the other hand, they also have technological importance in energy recovery, transportation and storage. We have recently demonstrated (Science 2004) that hydrogen molecules can be stored in binary H2/THF (tetrahydrofuran) clathrate hydrates at pressures nearly two orders of magnitude lower than that in pure hydrogen hydrates. This decreased pressure makes binary clathrate hydrates a potentially feasible hydrogen storage material, with a unique combination of advantages not found in any other class of materials.
The ultimate goal of our research is to advance our understanding of the nucleation, crystallization, and agglomeration mechanisms for natural gas hydrates. The results will have immediate relevance to flow assurance in gas/oil flowlines, and energy transportation and storage. Specifically we are aiming to (a) develop molecular-scale models of the aqueous structures which occur in solution immediately prior to and during the growth of gas hydrates, (b) investigate the effects of inhibitor and promoter molecules on these local structures, and, (c) using these data, identify possible pathways which may occur in the process of hydrate formation. This program combines microscopic (vibrational spectroscopy and neutron diffraction coupled to computer simulations) and macroscopic measurements (differential scanning calorimetry) to provide mechanistic information on hydrate nucleation, growth, and decomposition. The different methods help assure correct interpretation of the measurements and provide a solid foundation for accurate model development.
selected Publications
Sloan, E.D. and Koh, C.A., “Clathrate Hydrates of Natural Gases”, 3rd Edition, Taylor & Francis/CRC Press (2008) – “3rd Edition of a Bestseller” quoted from CRC Press Publishers (720 pages in Length).
Strobel, T.A., Sloan, E.D., Koh, C.A., “Raman Spectroscopic Studies of Hydrogen Clathrate Hydrates”, Journal of Chemical Physics, 2009, 130, 014506-10.
Nicholas, J.W., Dieker, L.E., Sloan, E.D., Koh, C.A., “Assessing the Feasibility of Hydrate Deposition on Pipeline Walls—Adhesion Force Measurements of Clathrate Hydrate Particles on Carbon Steel”, Journal of Colloid and Interface Science, 2009, 331, 322-328.
Ohno, H., Strobel, T.A., Dec, S.F., Sloan, E.D., Koh, C.A., “Raman Studies of Methane-Ethane Hydrate Metastability”, Journal of Physical Chemistry B, 2009, 113, 1711-1716.
Shin, K., Kim, Y., Strobel, T.A., Prasad, P.S.R., Sugahara, T., Lee, H., Sloan, E.D., Sum, A.K., Koh, C.A., “Tetra-n-butylammonium Borohydride Semiclathrate: A Hybrid Material for Hydrogen Storage”, Journal of Physical Chemistry A, 2009, DOI: 10.1021/jp902547d.
Strobel TA, Kim Y, Andrews GS, Ferrell, J.R., Koh, C.A., Herring, A.M., Sloan, E.D., “Chemical-Clathrate Hybrid Hydrogen Storage: Storage in Both Guest and Host”, Journal of the American Chemical Society, 2008, 130, 14875.