纳米粒子对CO2水合物导热性能的影响

试验研究了不同种类（Al₂O₃、Cu、SiO₂）、不同质量分数（0.05%、0.1%、0.15%）及不同粒径（10、30、50 nm）的纳米粒子对CO₂水合物热导率的影响。结果表明温度为-5~5℃时，纯CO₂水合物热导率为0.553~0.5861 W·m^-1·K^-1，具有玻璃体的变化特性。分散剂SDBS的加入，可改善CO₂水合物-纳米粒子体系的导热性能。在相同的质量分数和粒径下，纳米Cu粒子对CO₂水合物热导率的增强作用最好，但综合考虑水合物生成特性和溶液悬浮稳定性，选用纳米Al₂O₃粒子较合适。Al₂O₃粒子粒径越小，水合物热导率越大，15 nm比50 nm纳米粒子体系中CO₂水合物热导率的增长率平均提高了12.7%。此外，CO₂水合物热导率随Al₂O₃粒子质量分数的增大而增大，质量分数由0.05%增加到0.15%时，水合物热导率的增长率由4.2%提高到8.2%。

Effects of nanoparticles on CO2 hydrate thermal conductivity

The thermal conductivity of CO₂ hydrate was measured in this study. The effects of three kinds of nanoparticles, including Al₂O₃, Cu, and SiO₂, with different mass fractions (0.05%, 0.1%, and 0.15%) and different nanoparticle dimensions (10, 30, and 50 nm) on CO₂ hydrate thermal conductivity were investigated. The results show that CO₂ hydrate thermal conductivity increases with the increase of temperature, ranging from 0.553 to 0.5861 W·m^-1·K^-1 at -5-5℃. And the additive of dispersant SDBS has positive influence on thermal conductivity of CO₂ hydrate-nanoparticle system. With the same mass fraction and particle size, Cu nanoparticles show better effect to enhance CO₂ hydrate thermal conductivity than Al₂O₃ and SiO₂ nanoparticles. But considering the formation of CO₂ hydrate and the suspension stability of solution, Al₂O₃ is more suitable to be used as the promoter of thermal conductivity. The thermal conductivity of CO₂ hydrate increases with the decrease of particle size of the Al₂O₃ nanoparticles. The increase rate of thermal conductivity in 15 nm hydrate-nanoparticle system is 12.7% higher than that in 50 nm hydrate-nanoparticle system. In addition, the increase of CO₂ hydrate thermal conductivity is improved from 4.2% to 8.2% when the mass fraction of Al₂O₃ nanoparticles increases from 0.05% to 0.15%.