甲烷水合物热稳定性的研究

STUDY ON PRESERVATION OF METHANE HYDRATE

要利用天然气水合物实现对天然气的工业储运,就需要提高水合物的储气量并解决水合物的解析速度问题.为此,研究了在阴离子表面活性剂十二烷基硫酸钠(SDS)体系中,甲烷水合物在冰点以下的常压分解规律.结果表明,随着温度的降低,水合物的分解受到自我保存性质的影响,分解速度减慢.在温度范围为269.1～266.1 K之间,甲烷水合物的分解速度存在突变;利用外推法计算260.1 K时甲烷水合物完全分解需要21 d,说明水合物的自我保存性质对气体水合物储运技术具有重要意义.实验也发现SDS体系中生成的甲烷水合物颗粒尺寸较小,颗粒堆积结构近似多孔介质,对甲烷气体有一定吸附作用.

To commercially store and transport natural gas by gas hydrate, it is necessary to improve the gas-storing capacity and the decomposition velocity of the hydrate. Therefore, the decomposition law of methane hydrate under the atmospheric pressure and minus temperature is studied in the system of SDS. The result shows the decomposition velocity slows down as the temperature decreases since decomposition of hydrate is effected by its preservation. The decomposition velocity changes suddenly when the temperature is in the range from 266. 1 to 269. 1K. With calculation by extrapolation method, it takes 21 days for methane hydrate to decompose completely at 260. 1K, which explains the self-preservation property of hydrate makes important sense for the hydrate storing and transporting technology. Also, the experiments find the grain size of methane hydrate created in the SDS system is small, and the deposit configuration of the grains is similar with porous medium, which has adsorption effect to methane.