## 3 Results and Discussion
### Effect of Dissociation and Evaporation Rates
Under the conditions of the conductive heating of a gas hydrate particle, at a high dissociation rate (0.1 kg/m\({}^{2}\cdot\)s), the sample was heated from below when it was in close contact with the heated metal cylinder. Above the particle, an ice crust developed and then melted, while below it, gas was released from the pores, enhancing the ignition of the gas-vapor mixture. This can explain a sharp reduction in the ignition delay times (by up to 85%) with an increase in the mass dissociation rate in Figure 5c. Figure 6a-c presents the temperature fields in the gas hydrate ignition area when using convective heating and varying the mass dissociation rate for a heating source temperature of 1273 K. Significantly, the temperature traces were distributed identically around the gas hydrate particle with \(R_{\rm g}\) = 0.5 mm, irrespective of the dissociation rate. The ice in the gas hydrate composition melts to produce water. Liquid evaporation has a decisive effect on the characteristics of gas hydrate ignition and combustion at relatively low temperatures [1]. The water vapors were found [1] to significantly change the development of some elementary reactions (chemical effect), which led to a lower flame temperature. The vapor resulting from the water evaporation also reduces the combustion rate [1]. The evaporation rate of water generated on the gas hydrate surface is unstable as it is conditioned by dissociation, which, in turn, occurs at different rates depending on the different factors and conditions described above. The water evaporation rate affects the release of gas from the hydrate pores and the self-preservation phenomenon that suppresses the gas release. The more slowly the water evaporates from the surface, the higher the risk of the formation of an ice crust under certain conditions. The ice crust clogs the channels emerging from the pores for combustible gas release. Therefore, the rate of water evaporation from the gas hydrate surface is the key factor in the kinetics of hydrate combustion that should be taken into account and analyzed. Figure 7a-c presents the gas hydrate ignition delay times when varying the mass evaporation rate of water and the heating source temperature using radiant, convective, and conductive heating schemes. It is clear from Figure 7 that the ignition delay times changed steadily with the growth in the mass rate of water evaporation from the hydrate particle surface. At a heating source temperature of 1273 K, the ignition delay times for all of the heating schemes (radiant, convective, and conductive) increased by 63%, 23%, and 4%, respectively, with an increase  
Figure 5: The ignition delay times of the gas hydrate (\(R_{\text{g}}\) = 0.5 m) when varying the dissociation rate and temperature for the three heat exchange schemes: (**a**) radiant, (**b**) convective, (**c**) conductive. in the mass evaporation rate of water from 0.005 kg/m\({}^{2}\cdot\)s to 0.05 kg/m\({}^{2}\cdot\)s. At \(T\) = 1273 K, a rise in the mass evaporation rate to 0.1 kg/m\({}^{2}\cdot\)s increased the ignition delay times by 15%, on average, when convective and conductive heating were applied (Figure 7b,c). Under the conditions of radiant heating, at the same heating source temperature and evaporation rate, the ignition delay times increased almost three-fold (Figure 7a). Under the conditions of conductive heating, the ignition delay times increased with a rise in the mass evaporation rate of water by 10-80% (Figure 7c). Such changes in the ignition delay times can be explained by the following. When the dissociation rate reaches its peak, the ice on the gas hydrate particle surface quickly melts and water evaporation becomes more rapid. With an increase in the heating source temperature, the water film on the particle surface builds up and becomes thicker, thus preventing the release of gas from the hydrate. When gas passes through a thick water film, small methane-propane bubbles appear. The bubble then collapses to release gas, which leads to a local flame.