255962 Theory of Gas Hydrates: Effect of the Approximation of Rigid Water Lattice

Wednesday, October 31, 2012: 12:49 PM
412 (Convention Center )
Hrushikesh Pimpalgaonkar, Shivanand Vessam, Srikanth Ravipati and Sudeep Punnathanam, Chemical Engineering, Indian Institute of Science, Bangalore, India

One of the assumptions of the van der Waals and Platteeuw theory for gas hydrates is that the host water lattice is rigid and not distorted by the presence of guest molecules. In this work, we study the effect of this approximation on the triple-point lines of the gas hydrates. We calculate the triple-point lines of methane and ethane hydrates via Monte Carlo molecular simulations and compare the simulation results with the predictions of van der Waals and Platteeuw theory. Our study shows that even if the exact intermolecular potential between the guest molecules and water is known, the dissociation temperatures predicted by the theory are significantly higher. This has serious implications to the modeling of gas hydrate thermodynamics, and in spite of the several impressive efforts made toward obtaining an accurate description of intermolecular interactions in gas hydrates, the theory will suffer from the problem of robustness if the issue of movement of water molecules is not adequately addressed.

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See more of this Session: Thermophysical Properties and Phase Behavior IV
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