Comparing the dissociation kinetics of various gas hydrates during combustion: Assessment of key factors to improve combustion efficiency

摘要

To date, most studies concern the combustion of methane hydrate. There are neither data comparing combustion of various types of gas hydrates, nor those on the kinetics of dissociation of methane hydrate and double gas hydrates, which have different types of the unit cell. Alongside with the extraction and use of natural gas hydrates, there is an increasing interest in artificial gas hydrate technologies. In this regard, different types of combustible gases may be proposed. The present study deals with the combustion of methane hydrate and double gas hydrates (methane-propane) and (methane-isopropanol). Simple expressions have been obtained to estimate the effect of several factors on dissociation and combustion: for air velocity, heat flux density, temperature difference, and geometric parameters of the combustion region. The kinetics of dissociation of the studied gas hydrates differs significantly. It is shown that the velocity of the flame front has a highly nonlinear character, which is associated with the phenomenon of "self-preservation" of the gas hydrate. The obtained instantaneous velocity fields demonstrate a noticeable effect of thermogravitation convection on the velocity profile in the boundary layer. The resulting expressions and the experimental data can be effectively used for the development of the combustion technologies of gas hydrates and solid fuel degassing technologies.