CO2置换法开发不同体系CH4水合物的实验

CO₂置换法引起了许多研究者的注意，该方法能够使CH₄水合物开发和CO₂气体的长期储存同时进行，是一种开发CH₄水合物的新方法。在自行设计的反应装置中考察了3.25 MPa压力下，温度271.2 K、273.2 K和276.0 K时CO₂气体置换十二烷基硫酸钠（SDS）体系和纯水体系CH₄水合物中CH₄的置换过程。实验表明：提高温度有利于置换反应的进行；SDS体系的置换速率比纯水体系的置换速率高。276.0 K、3.25 MPa时，SDS体系和纯水体系100 h的置换效率分别达到6.93% 和14.50%。由于水合物相中静态水的存在，置换反应过程中，CO₂的消耗量与CH₄水合物的分解量并不是1∶1的关系。基于实验结果，简单地分析了CO₂置换CH₄水合物中CH₄的置换机理。

EXPERIMENTAL STUDIES ON CH4 RECOVERY FROM HYDRATE USING CO2 IN DIFFERENT SYSTEMS

One method proposed for CH4 hydrate recovery by use of CO2 has attracted many attentions by many experts. Not only does this method supply a way for CH4 recovery, but it also supplies a way for long term storage of CO2 at the same time. This study carried out a lab tests on the whole process of CH4 recovery from CH4 hydrate formed in sodium dodecyl sulfate system and pure water system by using the pressurized CO2 in a self designed device observed under a constant pressure of 3.25 MPa and the temperatures of 271.2 K, 273.2 K, and 276.0 K respectively. The experimental data showed that increasing the temperature was beneficial to improve replacement reaction rate. Compared with pure water system, the replacement efficiency of SDS system was higher. The replacement efficiencies of SDS system and pure water system within 100 hours reached 6.93% and 14.50% respectively under the temperature of 276.0 K and the pressure of 3.25 MPa. Due to the presence of static water in the CH4 hydrate, the molar ratio between the CO2 consumption and CH4 hydrate decomposition was not 1∶1. Based on the kinetic data, a simple replacement mechanism of CH4 recovery from CH4 hydrate was proposed.