Dissociation of methane and carbon dioxide hydrates: Synergistic effects

Abstract

The dissociation and combustion of methane hydrate samples were studied experimentally in a laboratory-scale combustion chamber with variable thermal conditions. The temperature in the combustion chamber was varied from 800 °C to 1000 °C to reproduce high-potential reactors and combustion chambers. Ignition delays, combustion times, and combustion product compositions were determined for gas hydrates in the form of granules and tablets. Synergistic effects were analyzed from the simultaneous dissociation of methane and carbon dioxide hydrate samples. Critical conditions were determined in which carbon dioxide prevented methane ignition. The definable parameters were determined as functions of the arrangement schemes of two gas hydrates and input experimental parameters, and the corresponding predictive mathematical expressions were obtained. Methane hydrate granules were found to ignite significantly faster than methane hydrate tablets. An increase in the temperature in the combustion chamber was proved advisable in the case of methane hydrate tablets. Granulated hydrate samples ignited consistently in a wide range of temperatures, and the ignition delay times changed negligibly with varying temperature. The methane hydrate combustion stability was analyzed, and a model was developed describing the patterns and predicting the carbon dioxide hydrate flow rate required for fire suppression. Finally, conditions were identified in which the synergistic effects of simultaneously dissociating hydrates with flammable and nonflammable gases would make it possible to effectively manage their safe and sustainable application in the energy industry.