This paper reports an investigation for solvation structure of supercritical CO₂ (scCO₂) and brine mixture for CO₂ plume geothermal (CPG) applications. Molecular dynamics simulations are performed to calculate radial distribution function, coordination number and hydrogen-bond number for mixtures of different compositions. This study can help reveal the solvation structures of scCO₂/brine mixture under different temperatures (373.15 K–473.15 K) and ion concentrations (1 wt% to 10 wt%). Results show that H₂O molecules bind more tightly to Na⁺ ion than Cl⁻ ion while scCO₂ molecules seem have a uniform distribution in the scCO₂/brine mixture. Both the interaction of Na⁺-H₂O pairs and that of Cl--H₂O pairs become stronger under higher temperature conditions. Besides, the increase of ion concentration not only reduces the number of H₂O molecules in the solvation shell of Na⁺ ion, but also weakens the interaction of hydrogen bonds. Moreover, it seems that the scCO₂/brine mixture is heterogeneous in the CPG application.

本文报道了针对CO ₂羽状地热（CPG）应用的超临界CO ₂（scCO ₂）和盐水混合物的溶剂化结构的研究。进行分子动力学模拟以计算不同组成的混合物的径向分布函数，配位数和氢键数。这项研究可以帮助揭示scCO ₂ /盐水混合物在不同温度（373.15 K–473.15 K）和离子浓度（1 wt％至10 wt％）下的溶剂化结构。结果表明使得h ₂水分子结合更紧密地与Na ⁺离子比氯^-离子而SCCO ₂分子似乎具有在SCCO均匀分布₂ /盐水混合物。在高温条件下，Na ⁺ -H ₂ O对和Cl-H ₂ O对的相互作用都更强。此外，离子浓度的增加不仅减少了Na ⁺离子的溶剂化壳中H ₂ O分子的数量，而且削弱了氢键的相互作用。而且，在CPG应用中似乎scCO ₂ /盐水混合物是异质的。