Experimental Verification of CH4 – CO_2 Replacement in Various Gas Hydrate Structures for CH4 Production and CO_2 Sequestration

摘要

In this study, the influence of CO_2 injection into various gas hydrates (CH_4 hydrate for sI, CH_4 + C_3H_8 hydrate for sII, and CH_4 + methylcyclopentane (MCP) hydrate for sH) was investigated to reveal the replacement mechanism. The thermal properties were measured using HP μ-DSC. The structure of gas hydrates was analyzed using PXRD. For sI hydrate, there was no structural transformation after replacement even though the hydrate equilibrium was shifted to stable regions. For sII hydrate, PXRD analysis showed partial structural transition during replacement. For sH hydrate, the significant heat exchange during replacement indicated dissociation and reformation of hydrate.