Wettability of Supercritical CO2-Brine-Mineral: The Effects of Ion Type and Salinity
Wettability of Supercritical CO2-Brine-Mineral: The Effects of Ion Type and Salinity
复制标题
超临界 CO2-盐水-矿物的润湿性：离子类型和盐度的影响
DOI：
10.1021/acs.energyfuels.7b00840
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发表时间：
2017-07-01
期刊：
影响因子：
5.3
通讯作者：
Song, Yongchen
中科院分区：
文献类型：
--
作者：
Chen, Cong;Chai, Zhuang;Song, Yongchen
深层盐水层被认为是封存二氧化碳的理想场所。界面张力和接触角是多孔介质中CO2/盐水/矿物体系传热传质过程的关键参数。采用分子动力学模拟方法研究了20 MPa、318.15 K条件下盐水矿化度和离子类型对CO2/盐水/矿物体系润湿性的影响。四种常见的盐水被选择为NaCl，KCl，CaCl 2，和MgCl 2。界面张力，水接触角，氢键结构和动力学进行了分析。盐水盐度和离子类型对水接触角的影响是非常复杂的。对于MgCl 2和NaCl溶液，接触角随盐度增加而增加。对于CaCl 2和KCl溶液，接触角首先增加，然后保持恒定的盐度。IFT（CO2-盐水）和CA的余弦的产品被发现是恒定的所有盐水溶液的研究。在实验测量的接触角的大的不确定性的背景下，这一发现是非常有用的预测接触角使用界面张力数据。由于IFT（CO 3-卤水）x cos（CA）通常与毛细管压力和残余捕集能力有关，这一发现也非常有助于在不同卤水条件下预测这些参数。需要做更多的工作来研究压力、温度和固体表面结构对这种关系的影响。
Deep saline aquifers are considered as perfect storage sites to sequestrate CO2. Interfacial tensions (IFTs) and contact angles (CAs) are key parameters in the heat and mass transfer processes for CO2/brine/mineral Systems in porous media. In the present study, a molecular dynamics simulation method was used to investigate the effects of brine salinity and ion type on wettability of CO2/brine/mineral systems at 20 MPa and 318.15 K. Four common brines were selected as NaCl, KCl, CaCl2, and MgCl2. Interfacial tensions, water contact angles, and hydrogen bond structure and dynamics have been analyzed. The effects of brine salinity and ion type on water contact angles were found to be very complicated. For MgCl2 and NaCl solutions, the contact angle increases with salinity. For CaCl2 and KCl solutions, contact angle first increases and then remains constant with salinity. The product of IFT(CO2-brine) and the cosine of CA was found to be constant for all brine solutions studied. In the context of large uncertainty of experimentally measured contact angles, this finding is very useful to predict contact angles using interfacial tension data. Due to the fact that IFT(CO3-brine) x cos(CA) is usually related with capillary pressure and residual trapping capacity, this finding is also very helpful to predict these parameters at different brine conditions. More work is required to study the effects of pressure, temperature, and solid surface structure on this relationship.