Thermal structure of methane hydrate fueled flames

An experimental and computational study investigates the burning behavior of methane hydrate in an opposed-jet porous burner. The free (convection) burning of methane hydrates is unstable and flame extinction can occur due to water film layer buildup or self-preservation phenomena. The burner allows us to overcome these problems and generates, for a limited time, a stable 1-D methane hydrate diffusion flame. Axial temperature, flame location, and flame width were measured using color-ratio thin filament pyrometry (TFP) from the radiative emission of a silicon carbide fiber that is oriented across the flame. The hydrate flame temperatures are found to be close to 1700 K. Computationally, chemical kinetic calculations with water vapor introduced into the fuel stream, and the opposed flame model and the GRI MECH 3.0 mechanism, simulated conditions of methane hydrate diffusion flames in order to observe the temperature, flame position and thermal width. The computational and experimental results showed close agreement in temperature and indicate that water from the hydrate dilutes the fuel and reduces flame temperatures to approximately 1700 K. TFP allowed us to capture the dynamic movement of the hydrate flame toward the air side as it burned robustly during a process where heat and mass transfer promoted a release in methane and water vapor entrainment into the reaction zone. (C) 2016 by The Combustion Institute. Published by Elsevier Inc.