整体煤气化联合循环合成气水合物法分离CO2的分子动力学模拟

利用分子动力学（MD）模拟方法研究整体煤气化联合循环（IGCC）合成气（CO₂/H₂）水合物法分离CO₂的分离机理，系统研究了CO₂水合物、H₂水合物以及合成气水合物法一级分离所得CO₂/H₂混合气体水合物的微观结构及性质.模拟分析n个CO₂或H₂与水合物笼状结构的整体结合能ΔE关键词： 水合物法分离 分子动力学模拟 整体煤气化联合循环合成气 2分离')" href="#">CO₂分离

Molecular dynamics simulation of CO2 separation from integrated gasification combined cycle syngas via the hydrate formation

Molecular dynamics (MD) simulation is used to study the microscopic mechanism of CO₂ separation from integrated gasification combined cycle(IGCC) syngas (CO₂/H₂) via the hydrate formation. The stable structures and microscopic properties of CO₂ hydrate, H₂ hydrate, and CO₂/H₂ hydrate from one stage separation for IGCC syngas are investigated systematically. The binding energy for loading the hydrate structure with the guest molecules, ΔE_n, was analyzed. It was shown that the binding between CO₂ and water is more stable than that between H₂ and water. That is, CO₂ can more easily form the hydrate. Therefore, CO₂ in the CO₂/H₂ gas mixture more easily transfers into the hydrate phase. Based on this, CO₂ can be separated from the IGCC syngas. The binding energy for loading the single cavity with the guest molecules, ΔE_GH, was analyzed. It was found that the gas mixture can form structure Ⅰ(SⅠ) hydrate, in which CO₂ molecules preferably occupy the big cavity and then occupy the small cavity, and H₂ molecules only occupy the small cavity. The simulation was carried out at pressure of 85 MPa and temperature of 2737 K for the stable structure of the CO₂/H₂ hydrate in one stage separation for IGCC syngas. From the ΔE_n and ΔE_GH of the systems with H₂ single and double occupancy in the small cavity, it is concluded that the configurations with the single occupancy is most stable. The stable structure of the hydrate in one stage separation is attained by MD. It provides a theoretical evidence of CO₂ separation for formation hydrate in IGCC syngas.