二氧化碳置换法开发天然气水合物的实验研究

Experimental Research on Methane Recovery from Natural Gas Hydrate by Carbon Dioxide Replacement

考察了温度在270.15-278.15K,压力在2.3-4.0MPa条件下应用CO2置换天然气水合物中CH4的置换过程。结果表明,温度和压力是置换反应速度和效率的重要影响因素。温度和压力越高,越有利于反应的进行。而压力的影响没有温度的影响明显。同时,置换过程中进入水合物相的二氧化碳的摩尔量与气相中CH4增加的摩尔量的比率超过了1：1,这可能是由于纯水水合物的甲烷含气量并未达到理论含气量,置换的同时有部分二氧化碳分子进入水合物的空孔穴和游离水中,形成二氧化碳水合物和水溶液。

The replacement process of methane from nature gas hydrate by CO2 was studied at the temperature of 270.15-278.15 K and under the pressure of 2.3-4.0 MPa. The results indicate that the temperature and pressure are two important factors for the replacement process. Increasing the operating temperature and pressure would result in faster reaction velocity and higher efficiency, however, between them, the effect of pressure is weaker than that of temperature. The replacement ratio of the amount of CO2 sequestrated in the hydrate phase to that of decomposed methane from nature gas hydrate excesses 1：1, which is probably because of the CH4 gas storing capacity of hydrate formed in pure water system hasn＇t reach the theoretical storing capacity, thus some CO2 molecule enter the empty space of the hydrate, some dissolve in the dissociated water and they become CO2 hydrate and solution.