纳米SiO2分散液中CO2水合物生成促进与稳定机制实验研究OA

CO2 hydrate-based technology exhibits broad application potential for carbon capture and storage(CCS).However,its industrial deployment is still hindered by several key challenges,including sluggish hydrate nucleation and growth kinetics,insufficient stability,and high susceptibility to decomposition under fluctuating ambient temperature and pressure conditions.The promotion effect of nano-SiO2 on CO2 hydrate formation was investigated,as well as the underlying mechanism governing hydrate stability.Specifically,the nucleation induction time,formation rate and decomposition behavior of CO2 hydrate in both nano-SiO2 dispersions and pure water were characterized systematically.The results demonstrate that,with the addition of 0.5%(mass fraction)nano-SiO2 with particle size of 60 nm,the nucleation induction time of CO2 hydrate is significantly reduced from 36 min to 24 min,while the average formation rate increases from 0.198 mmol/min to 0.288 mmol/min,corresponding to a 45%enhancement.Furthermore,under ambient conditions(293.15 K,101.325 kPa),the hydrate decomposition time is extended from 39 min to 90 min,confirming a remarkable improvement in hydrate stability.The reason is that nano-SiO2 reduces the nucleation energy barrier of CO2 hydrate through its high specific surface area and surface activity,which facilitates heterogeneous nucleation and reaction heat dissipation.Meanwhile,it can form a protective encapsulation layer on the hydrate surface to effectively retard heat transfer,thereby enhancing both the formation kinetics and stability of CO2 hydrate.The study can provide a valuable reference for the deployment of nanomaterial-enhanced hydrate technology in CCS applications.