Thermodynamic Inhibition by Chlorides (KCl, NaCl, CaCl 2 , and MgCl 2 ) on CO 2 Hydrates: Implication on Hydrate-Based CO 2 Sequestration

作者：Junjie Ren, Siyu Zeng, Yunting Liu, Chenlu Xu, Hongfeng Lu, Jianzhong Zhao, Praveen Linga, Zhenyuan Yin · 发表于：Energy & Fuels · 年份：2025 · DOI：10.1021/acs.energyfuels.5c02264 · 被引用次数：13 · 研究领域：Methane Hydrates and Related Phenomena、CO2 Sequestration and Geologic Interactions、Atmospheric and Environmental Gas Dynamics

Hydrate-based CO 2 sequestration in marine sediments has emerged as a promising strategy to mitigate global climate change due to its substantial storage capacity and operational feasibility. However, understanding the influence of chloride salts from seawater, such as KCl, NaCl, CaCl 2, and MgCl 2, on CO 2 hydrates phase stability is essential for the practical application of subsea CO 2 sequestration as hydrates. This study systematically investigates the phase equilibria of CO 2 hydrates in KCl, NaCl, CaCl 2, and MgCl 2 solutions at concentrations of 0–400 mM, encompassing typical marine salinity conditions. The experimental results demonstrate that all four chloride salts exhibit thermodynamic inhibition effects on CO 2 hydrates, with the inhibitory effect intensifying as concentration increases. MgCl 2 exerts the strongest thermodynamic inhibition effect, suppressing CO 2 hydrates equilibrium temperature by 0.96 K at 200 mM and 1.57 K at 400 mM concentrations under 3.0 MPa. The inhibition strength follows the order of MgCl 2 > CaCl 2 > NaCl > KCl, which correlates well with the ion charge and radius of cations. A thermodynamic model was developed by integrating the Hu-Lee-Sum correlation of water activity with the classical Chen-Guo model for the prediction of the thermodynamic phase equilibria for CO 2 hydrates. The proposed model demonstrates high accuracy, with an average absolute deviation of pressure below 2.0% across all tested concentrations. Validation against ex...