Experimental and Theoretical Study of Diffusion Combustion of Methane above a Gas Hydrate Layer in a Laminar Air Flow

The fraction of methane in gas hydrates is approximately 12% (by weight). Theoretically, the combustion temperature of such a composition is rather low. Nevertheless, the measurements show that a much higher flame temperature can be ensured by organizing the process more appropriately. For this purpose, it is necessary to separate the dissociation and combustion regions (i.e., eliminate water heating). On the other hand, for combustion to be stable, some part of the combustion heat should be returned to the hydrate region to maintain the dissociation rate at a needed level. Stability of methane hydrate combustion is naturally determined by the ratio of heat release and heat transfer. This paper describes experiments on methane combustion above a layer of a dissociating gas hydrate, and a simple mathematical model is proposed for estimating diffusion combustion stability. Comparing the modeling results with experimental data allows one to determine the water vapor concentration and find the thermal balance of hydrate combustion.