Abstract:

Based on the action mechanisms of solid promoters and chemical promoters, the effects of CP hydrate seeds + THF solid-liquid compound promoters on the formation of CO₂ hydrates in brine systems and their influences were studied. Through macroscopic experiments combined with characterization methods such as laser Raman spectroscopy and scanning electron microscopy (SEM), the influence laws of different concentration combinations of the solid-liquid compound promoters on the growth kinetics, gas consumption, and hydrate morphology of CO₂ hydrates were obtained. The experiments showed that the synergistic effect of CP hydrate seeds + THF effectively improved the formation efficiency and rate of CO₂ hydrates; In the brine system, when the optimal molar fraction combination was 2.78% CP + 2.78% THF, the CO₂ gas consumption reached 23.90 mmol and the average formation rate of hydrates was 2.94×10^-⁴ mmol/(mol·s), which was 15.00% and 66.67% higher than the results previously reported, respectively. In addition, microscopic analyses by SEM and Raman spectroscopy reveal that, in a pure water system, hydrate formation is diffusion-controlled and characterized by high gas consumption. By contrast, in a brine system, hydrate formation is limited by surface reactions, and the electrostatic effect of salt ions makes the hydrate interface denser, thereby significantly reducing the gas consumption. The experiments simulating the process of CO₂ hydrate sedimentation in marine environment have shown that the CO₂ hydrates synthesized in salt water have a higher density and are more prone to sedimentation, which is more conducive to marine carbon sequestration. These microstructure characteristics were consistent with the macroscopic experimental data, verifying the effectiveness of the solid-liquid compound promoter system. This achievement provides a key parameter optimization scheme and theoretical support for marine carbon sequestration technology, and has important application value for achieving efficient and stable marine carbon dioxide sequestration.

Key words: CO₂ capture, hydrate, ocean carbon sequestration, kinetics, solid-liquid compound mixture promoter

摘要：

基于固体促进剂和化学促进剂的作用机理，研究了CP水合物晶种+THF固液复配型促进剂对盐水体系中CO₂水合物形成及影响，通过宏观实验结合激光拉曼、扫描电子显微镜（SEM）等表征方式，获得了不同浓度组合固液复配促进剂对CO₂水合物生长动力学、气体消耗量以及水合物形貌等影响规律。研究表明，CP水合物晶种+THF的协同作用有效地提升了CO₂水合物的形成效率及形成速率；盐水体系中，最佳摩尔分数组合为2.78% CP+ 2.78%THF时，CO₂气体消耗量达到23.90 mmol，水合物的平均生成速率为2.94×10^-4 mmol/(mol·s)，相较于已报道的结果，分别提高了15.00%和66.67%。此外，由SEM和Raman等微观分析手段可以得出，纯水体系中水合物形成受扩散控制，气体消耗量普遍较高，而盐水体系则受控于界面反应，盐离子的静电效应使得水合物界面更致密，从而显著降低了气体消耗量。模拟海洋环境中的CO₂水合物沉降过程实验表明，盐水中合成的CO₂水合物密度更大且易于沉降，更有利于海洋碳封存。这些微观结构特征与宏观实验数据一致，验证了固液复配型促进剂体系的有效性。该成果为海洋碳封存技术提供了关键参数优化方案与理论支撑，对实现高效稳定的海洋二氧化碳封存具有重要应用价值。

关键词: 碳捕集, 水合物, 海洋碳封存, 动力学, 固液复配促进剂