Heat and mass transfer at the ignition of single and double gas hydrate powder flow in a reactor

•Critical ambient temperatures are established for hydrate granule ignition.•Ignition delay times are determined for gas hydrate granules in air.•The influence of neighboring hydrate granules is established on their ignition in a chamber.•A model is developed for predicting the hydrate granule ignition conditions.•A process scheme is proposed for the use of granulated hydrate for power production. This paper details the heat and mass transfer at the ignition patterns of single (methane) and double (methane-isopropanol) granulated hydrates in a heated air. The experiments were performed in a laboratory-scale combustion chamber in the form of an oblong reactor with free-falling powder of the gas hydrate granules. The air in the combustion chamber was heated by the walls with ceramic plate heaters. The variation ranges of the input parameters were chosen to match the capacities of modern energy generation systems. We established the ignition delay times of the gas hydrate granules, combustion regimes, and sizes of the flame zone behind moving granules. We also analyzed the joint influence of the gas hydrate granules on their ignition behavior. A model was developed to estimate the threshold boundary conditions of gas hydrate ignition in different-sized chambers, with variable hydrate component composition granule size. Gas hydrate dissociation rates were determined in different sections of the laboratory-scale combustion chamber. Thermal conditions were predicted in which gas hydrates consistently ignite in combustion chambers with minimum cooling of the chamber walls and minimum unburnt fuel. [Display omitted]