Thermal conductivity and thermal diffusivity of methane hydrate formed from compacted granular ice

Thermal conductivity and thermal diffusivity of pure methane hydrate samples, formed from compacted granular ice (0–75 μm), and were measured simultaneously by the transient plane source (TPS) technique. The temperature dependence was measured between 263.15 and 283.05 K, and the gas-phase pressure dependence was measured between 2 and 10 MPa. It is revealed that the thermal conductivity of pure methane hydrate exhibits a positive trend with temperature and increases from 0.4877 to 0.5467 W·m−1·K−1. The thermal diffusivity of methane hydrate has inverse dependence on temperature and the values in the temperature range from 0.2940 to 0.3754 mm2·s−1, which is more than twice that of water. The experimental results show that the effects of gas-phase pressure on the thermal conductivity and thermal diffusivity are very small. Thermal conductivity of methane hydrate is found to have weakly positive gas-phase pressure dependence, whereas the thermal diffusivity has slightly negative trend with gas-phase pressure.