Methane storage in mixed hydrates is advantageous due to faster kinetics and added stability. However, capacity needs to be improved. Here we study mixed hydrates of methane (CH₄) and tetrahydrofuran (THF), in the presence of sodium dodecyl sulfate (SDS) as a kinetic promoter for hydrate formation. We report the co-existence of pure methane (sI) and mixed CH₄-THF hydrates (sII) in the presence of SDS; however, in the absence of SDS, co-existence of pure THF (sII) and mixed CH₄-THF hydrates (sII) was observed. Thus the presence of SDS preferentially promotes the enclathration of methane over that of THF. Furthermore, through in situ Raman spectrometry, complemented by high-pressure differential scanning calorimeter, we present temperature-dependent methane occupancy in small and large cages of sI and sII hydrates. Our findings offer new insights for enhancing the methane storage capacity in more stable sII hydrate configuration for large-scale methane storage via solidified natural gas technology.

由于更快的动力学和增加的稳定性，混合水合物中甲烷的存储是有利的。但是，容量需要提高。在这里，我们研究十二烷基硫酸钠（SDS）作为水合物形成动力学促进剂的情况下，甲烷（CH ₄）和四氢呋喃（THF）的混合水合物。我们报道了在SDS存在下纯甲烷（sI）和混合的CH ₄ -THF水合物（sII）的共存；但是，在没有SDS的情况下，观察到纯THF（sII）和混合的CH ₄ -THF水合物（sII）共存。因此，与THF相比，SDS的存在优先促进甲烷的包合。此外，通过原位拉曼光谱法，辅以高压差示扫描量热仪，我们可以得出在小笼和大笼中的sI和sII水合物中甲烷的温度依赖性。我们的发现提供了新的见解，可通过固态天然气技术以更稳定的sII水合物构型提高甲烷存储能力，以进行大规模甲烷存储。