液态二氧化碳置换整形甲烷水合物过程特性

通过可视化水合物反应装置和影像设备，研究了注入液态CO2分解CH4水合物同时原位生成气体水合物并保持整块水合物结构稳定的完整过程，验证了水合物分解和生成同时进行的第二类原位置换过程的可行性. 通过控制压力实现在CO2?CH4混合水合物四相区(水合物?水?液相?气相)的CH4置换过程，得到富CH4气体产物. 通过分析气相色谱和测定产气量得到CH4产气特性和CO2对CH4水合物的置换率. 结果表明，低压有利于获得较优的置换效果，4.5 MPa下的置换过程较5 MPa时产气量提高14.6%，甲烷水合物置换率提高13.7%.

Process Characteristics on Replacement of Bulk-methane Hydrates with Liquid Cardon Dioxide

Second types of in situ replacement of methane hydrate by liquid carbon dioxide replacement were proposed and verified by experiments. Through visible hydrate reaction device and image equipment to intuitively record injecting CO2 and gas hydrate decomposition in situ hydrate, and maintain the bulk of hydrate stable structure, proved the feasibility of hydrate decomposition and generation in second types of in situ replacement process at the same time. By controlling the pressure properly, the CH4 replacement process in the four phase zone (Hydrate?Water?Liquid?Vapor) of the CO2?CH4 mixed hydrate was realized, and the rich CH4 gas production was obtained. The CH4 gas production characteristics and the replacement rate of CO2 to CH4 hydrate were analyzed by gas chromatography and gas production measurement. The results showed that lower pressure was favorable for obtaining better replacement effect, compared with 5 MPa, the gas production increased by 14.6% and the methane hydrate replacement rate increased by 13.7% at 4.5 MPa.