Dissociation of methane from a layer of methane-hydrate particles: A new simple model

Abstract

A simple model of the dissociation of methane from a layer of methane-hydrate particles is suggested. The model is based on the assumption that methane-hydrate particles form a flat porous film lying on an adiabatic wall. This film is heated by ambient air convection. It is assumed that when the temperature inside a certain region within the methane-hydrate reaches the critical temperature for the release of methane from the methane-hydrate, all methane is released from the methane-hydrate and the latter turns into ice. The contribution of heat required for the release of methane is considered. The model is based on the analytical solution to the one-dimensional heat transfer equation in the two-layer (methane-hydrate/ice) system. This solution is incorporated into the numerical code and used at each time step of the calculations. Model predictions are compared with experimental data for the heating of a layer of methane-hydrate of porosity 0.3 and thickness 5 mm. It is shown that good agreement between the predictions of the model and experimental data is observed at the initial stage of the process. At longer times, the model predicts faster methane release than observed experimentally unless the effect of self-preservation can be ignored. This deviation between modelling results and experimental data is attributed to the main assumption of the model that all methane is instantaneously released from the methane-hydrate when the methane-hydrate temperature reaches the above-mentioned critical temperature.