Carolyn A. Koh
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.
Z. M. Aman, K. Olcott, K. Pfeiffer, E. D. Sloan, A. K. Sum, and C. A. Koh, “Surfactant Adsorption and Interfacial Tension Investigations on Cyclopentane Hydrate,” Langmuir, 29 (8), 2676-2682 (2013). [doi: 10.1021/la3048714]
Z. A. Aman, S. Joshi, E. D. Sloan, A. K. Sum, and C. A. Koh, “Micromechanical Cohesion Force Measurements to Determine Cyclopentane Hydrate Interfacial Properties,” Journal of Colloid & Interface Science, 376 (1), 283-288 (2012). [doi: 10.1016/j.jcis.2012.03.019]
C. A. Koh, E. D. Sloan, A. K. Sum, and D. T. Wu, “Fundamentals and Applications of Gas Hydrates,” Annual Review of Chemical and Biomolecular Engineering, 2, 237-257 (2011). Invited. [doi: 10.1146/annurev-chembioeng-061010-114152]
M. R. Walsh, C. A. Koh, E. D. Sloan, A. K. Sum, and D. T. Wu, "Microsecond Simulation of Spontaneous Methane Hydrate Nucleation and Growth," Science, 326 (5956), 1095-1098 (2009). [doi: 10.1126/science.1174010]
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).
L.J. Florusse, C.J. Peters, J. Schoonman, K.C. Hester, C.A. Koh, S.F. Dec, K. Marsh, E.D. Sloan, “Molecular Clusters of H2 Stored in Binary Clathrate Hydrates at Near Ambient T & P”. Science, 2004, 306, 469-471. [DOI: 10.1126/science.1102076]