NH3作为CO2置换CH4水合物促进剂的分子动力学模拟研究

针对天然气水合物开采中CO₂置换面临的渗透性差、置换效率低的问题,采用分子动力学模拟方法,将对水合物相具有强穿透能力的NH₃作为促进剂,分别模拟了CO₂单组分和CO₂/NH₃混合组分置换水合物过程。结果表明:在模拟设定的温度压力范围内,245 K和255 K条件下,NH₃对CO₂置换水合物过程起到正向促进作用,而当温度升高至265 K时,则会对置换过程起到抑制作用；温度相同时,升高压力可以提高置换效率,但不会改变NH₃对置换过程的促进/抑制作用。该研究结果可为提高CO₂置换法的置换效率提供新的思路。 

Molecular dynamics simulation of NH3 as a promoter for CO2 replacement of CH4 hydrate

The problems of poor permeability and low replacement efficiency are faced during the mining of natural gas hydrates by CO₂ replacement. In this paper, based on the molecular dynamics simulation method, NH₃, which has strong penetrating ability to hydrate phase, is used as a promoter to simulate the replacement of hydrate by CO₂ single component and CO₂/NH₃ mixed components, respectively. The results show that within the range of temperature and pressure set by simulation, NH₃ plays a positive role in promoting the CO₂ replacement hydrate process at 245 K and 255 K, and it will inhibit the replacement process when the temperature rises to 265 K; at the same temperature, the increase of pressure will improve the displacement efficiency, but it will not change the promotion/inhibition effect of NH₃ on the replacement process. The results can provide new ideas for improving the replacement efficiency of CO₂ replacement method.