Abstract: This paper summarized recent phase equilibria research on replacement of CH4 from hydrate with CO2, including replacement mechanism, phase equilibria experiments, influence factors of mixed hydrate phase equilibria and the application of phase equilibria study. Electrolyte solution and microwave reflect the electrical force on the formation of hydrate. Interfacial tension, adsorption on the phase equilibria conditions need to be considered when using surfactants or porous medium. Impacts of gas component on hydrate formation were related to hydrate phase equilibria conditions and interaction between the components. Phase equilibria experiments used observation method, which may have errors, and not suitable for the research of hydrate formation in porous media. Therefore, the combination of microscopic imaging technique and chromatographic analysis technique may be needed in the experiment. The research on phase equilibria of liquid or emulsion CO2 may need to be future studied, considering its advantages in transportation, injection, separation and replacement effects. Actual conditions of the CO2 replacement process are different from experimental conditions, with greater impacts heat injection or depressurization. Therefore phase equilibria in multiple physical fieldschanges for porous medium sediments.

Key words: carbon dioxide, hydrate, phase equilibria, replacement

摘要： 总结了近年来国内外CO2置换CH4水合物的相平衡研究成果，包括置换机理、相平衡实验、混合水合物相平衡的影响因素及相平衡研究的应用。研究表明，电解质溶液、微波等体现了电场对水合物形成的作用力；表面活性剂、多孔介质需要考虑界面张力、吸附等作用对相平衡条件的影响；气体组分对水合物形成的影响与各自的水合物相平衡条件、组分之间的相互作用有一定关系。目前的相平衡实验研究多采用观察法，有一定的误差，并且无法研究多孔介质内的水合物形成情况，因此需要结合一些微观成像技术、色谱分析技术满足实验要求；液态或乳化液形式的CO2由于其运输、注入、分离、置换效果的优势受到了重视，但是相关的相平衡研究尚处于起步阶段；CO2置换的工程实际条件不同于实验室，注热或降压措施的影响范围较大，所以考虑多孔介质沉积层的多个物理场变化的相平衡研究将是今后研究的重要课题。

关键词: 二氧化碳, 水合物, 相平衡, 置换