000			02355nab a2200205 4500
005			20260520000839.0
008			260224s2009 xxu
245	0	0	_aModeling pure methane hydrate dissociation using a numerical simulator from a novel combination of x-ray computed tomography and macroscopic data
260			_a _b _cnov./dic. 2009
270			_a09/06/2010 ; 09/06/2010
300			_a8 p. ; 5958-5965
520			_aTranscripción del resumen del autor. The numerical simulator TOUGH+HYDRATE (T+H) was used to predict the transient pure methane hydrate (no sediment) dissociation data. X-ray computed tomography (CT) was used to visualize the methane hydrate formation and dissociation processes. A methane hydrate sample was formed from granular ice in a cylindrical vessel, and slow depressurization combined with thermal stimulation was applied to dissociate the hydrate sample. CT images showed that the water produced from the hydrate dissociation accumulated at the bottom of the vessel and increased the hydrate dissociation rate there. CT images were obtained during hydrate dissociation to confirm the radial dissociation of the hydrate sample. This radial dissociation process has implications for dissociation of hydrates in pipelines, suggesting lower dissociation times than for longitudinal dissociation. These observations were also confirmed by the numerical simulator predictions, which were in good agreement with the measured thermal data during hydrate dissociation. System pressure and sample temperature measured at the sample center followed the CH4 hydrate Lw+H+V equilibrium line during hydrate dissociation. The predicted cumulative methane gas production was within 5% of the measured data. Thus, this study validated our simulation approach and assumptions, which include stationary pure methane hydrate-skeleton, equilibrium hydrate-dissociation and heat- and mass-transfer in predicting hydrate dissociation in the absence of sediments. It should be noted that the application of T+H for the pure methane hydrate system (no sediment) is outside the general applicability limits of T+H.
581			_a6
773	0		_tEnergy & fuels _g23
942			_cARTICULO
100	1		_aGupta, Arvind _942385
100	1		_aMoridis, George J. _933629
100	1		_aKneafsey, Timothy J. _937731
999			_c170839 _d170839