Hydrate phase equilibrium for Ch4-CO2-H2O system in porous media
Hydrate phase equilibrium for Ch4-CO2-H2O system in porous media
复制标题
多孔介质中CH4-CO2-H2O体系的水合物相平衡
DOI：
10.1002/cjce.22529
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发表时间：
2016
影响因子：
2.1
通讯作者：
Yang Mingjun
中科院分区：
文献类型：
--
作者：
Song Yongchen;Wang Shenglong;Jiang Lanlan;Zhang Yi;Yang Mingjun
在水合物开采中置换CO2/CH4被认为是提高天然气产量和缓解温室效应的一种很有前途的方法。由于采矿水合物沉积物中的气体浓度随着驱替过程的变化而变化，因此研究不同混合气体存在下水合物的形成和解离特性是至关重要的。为了获得基本的热力学数据，对多孔介质中CO2/CH4混合气体水合物相平衡条件进行了实验研究。实验在276.55~284.85 K和2.10~6.8 Mpa下进行，采用等容法测定不同组成的CO_2/CH_4混合气体(CO_2摩尔分数分别为0.798、0.499和0.199 / (79.8、49.9和19.9mol%))。实验结果表明，在相同的温度(T)下，CO2摩尔分数越高的混合气体水合物平衡压力p越低。实验中使用的两种不同的多孔介质对混合气体水合物的相平衡条件影响不大。提出了一种改进的热力学模型来计算CO2/CH4水合物在多孔介质中的相平衡条件，预测结果与实验数据吻合较好。
CO2/CH4replacement in hydrate exploitation is considered a promising method to enhance natural gas production and mitigate the greenhouse effect. Since the gas concentration in mining hydrate sediment changes with the displacement process, it is crucial to investigate the hydrate formation and dissociation characteristics with the presence of different gas mixtures. To obtain fundamental thermodynamic data, CO2/CH4gas mixture hydrate phase equilibrium conditions in porous media were experimentally investigated. The experiments were conducted at 276.55–284.85 K and 2.10–6.80 MPa using an isochoric method with different CO2/CH4gas mixture compositions (CO2mole fractions were 0.798, 0.499, and 0.199 mol/mol (79.8, 49.9, and 19.9 mol%)). The results showed that gas mixtures with higher CO2mole fractions had lower hydrate equilibrium pressure (p) under the same temperature (T) according to the experimental data. The two different porous media used in the experiments had a slight influence on gas mixture hydrate phase equilibrium conditions. An improved thermodynamic model was proposed to calculate the CO2/CH4hydrate phase equilibrium conditions in porous media, and the prediction results fitted closely to the experimental data.