Sun Yue, Yu Hang, Yang Bo
School of Energy and Mining Engineering, China University of Mining & Technology Beijing, Beijing 100083, China.
School of Civil, Mining, Environmental and Architectural Engineering, University of Wollongong, Wollongong, NSW 2522, Australia.
Langmuir. 2024 Oct 29;40(43):22658-22672. doi: 10.1021/acs.langmuir.4c02412. Epub 2024 Oct 14.
Understanding the dissolution behavior of supercritical CO (scCO) in porous media is crucial for efficient CO storage. However, the precise modeling of dynamic dissolution behavior at this pore scale remains a huge challenge, and the impact of wettability on this process still needs to be clarified. In this study, the influence of rock wettability on CO dynamic dissolution in the three-dimensional porous media is investigated using the lattice Boltzmann method (LBM). The LBM is coupled with scCO-water two-phase flow, solute transport, and heterogeneous and homogeneous reactions. The size, number, and dissolution pattern of scCO bubbles during the dissolution process are observed under strongly water-wet, weakly water-wet, intermediate-wet, and mixed-wet conditions. The CO(aq) concentration and pH are investigated, followed by a quantitative investigation of the impact of wettability on the specific interface area and the mass transfer coefficient. An empirical relationship between the specific interface area and scCO saturation is established. The findings reveal that under weakly water-wet and intermediate-wet conditions, the sizes of scCO clusters and monomers are small and mostly distributed at the dead end of the pores. In contrast, under strongly water-wet and mixed-wet conditions, the clusters are larger and interconnected, and distributed in the center of the pore. This results in a greater scCO-water interface area, consequently enhancing the dissolution rate. Furthermore, a strong linear correlation is observed between scCO saturation and specific interface area. It is noted that as the hydrophilicity of the rock increases, the mass transfer coefficient initially rises and then declines.
了解超临界CO₂（scCO₂）在多孔介质中的溶解行为对于高效的CO₂储存至关重要。然而，在这种孔隙尺度下对动态溶解行为进行精确建模仍然是一个巨大的挑战，并且润湿性对该过程的影响仍有待阐明。在本研究中，使用格子玻尔兹曼方法（LBM）研究了岩石润湿性对三维多孔介质中CO₂动态溶解的影响。LBM与scCO₂-水两相流、溶质传输以及非均相和均相反应相耦合。在强水湿、弱水湿、中间湿和混合湿条件下观察了溶解过程中scCO₂气泡的尺寸、数量和溶解模式。研究了CO₂（aq）浓度和pH值，随后定量研究了润湿性对比表面积和传质系数的影响。建立了比表面积与scCO₂饱和度之间的经验关系。研究结果表明，在弱水湿和中间湿条件下，scCO₂团簇和单体的尺寸较小，大多分布在孔隙的死端。相比之下，在强水湿和混合湿条件下，团簇较大且相互连接，分布在孔隙中心。这导致了更大的scCO₂-水界面面积，从而提高了溶解速率。此外，观察到scCO₂饱和度与比表面积之间存在很强的线性相关性。值得注意的是，随着岩石亲水性的增加，传质系数最初上升然后下降。
