关键词: 碳捕集, 水合物, 海洋碳封存, 动力学, 固液复配促进剂

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