Clean Fossil Energy Research Center, Korea Institute of Energy Research, 102 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea.
J Phys Chem B. 2010 May 27;114(20):6973-8. doi: 10.1021/jp100812p.
Phase equilibria and formation kinetics of the natural gas hydrate in porous silica gels were investigated using the natural gas composition in the Korean domestic natural gas grid. The hydrate-phase equilibria in the porous media are found to shift to the inhibition area than that in the bulk phase. The measured phase equilibrium data, combined with the Gibbs-Thomson equation, were used to calculate the hydrate-water interfacial tension. The value was estimated to be 59.74 +/- 2 mJ/m(2) for the natural gas hydrate. In addition, the inhibition effect is observed to be more significant in the meso-sized pore than the macro-sized one. In the formation kinetics, it was found that the hydrate formation reached the steady-state in a short period of time without mechanical stirring. Furthermore, the formation rate was found to be faster at 275.2 K than 273.2 K even though the driving force at 273.2 K is larger than that of 275.2 K. Even though the porous silica gels have smaller volume than other methods for gas storage, the gas consumption was found to be significantly enhanced in this study (for example, 120 vol/vol for the silica gels and 97 vol/vol for wet activated carbon). In this regard, using porous silica gels can be a potential alternative for gas storage and transportation as a nonmechanical stirring method. Although this investigation was performed with the natural gas composition in the Korean domestic grid, the results can also be expanded for designing or operating any hydrate-based process using various gas compositions.
采用韩国国内天然气管网中的天然气组成，研究了多孔硅胶中天然气水合物的相平衡和生成动力学。多孔介质中的水合物相平衡被发现移向抑制区域，而不是在体相。测量的相平衡数据与吉布斯-汤姆逊方程结合，用于计算水合物-水界面张力。对于天然气水合物，该值估计为 59.74 +/- 2 mJ/m(2)。此外，在中孔中观察到抑制效果比大孔更显著。在生成动力学中，发现水合物在没有机械搅拌的情况下短时间内达到稳定状态。此外，即使在 273.2 K 时驱动力大于 275.2 K，在 275.2 K 时水合物的生成速率也比 273.2 K 时更快。尽管多孔硅胶的体积比其他气体储存方法小，但在这项研究中发现气体消耗显著增加（例如，硅胶为 120 体积/体积，湿活性炭为 97 体积/体积）。在这方面，使用多孔硅胶作为非机械搅拌方法可以成为气体储存和运输的潜在替代方法。虽然这项研究是在韩国国内电网中的天然气组成下进行的，但结果也可以扩展到使用各种气体组成设计或操作任何基于水合物的工艺。
