摘要: |
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。 |
关键词: 天然气水合物 氨气 甲烷 二氧化碳置换 分子动力学 |
DOI:10.3969/j.issn.1007-3426.2021.05.010 |
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Molecular dynamics simulation of NH3 as a promoter for CO2 replacement of CH4 hydrate |
Chen Wengang1, Li Dongze2
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1. Sinopec Star Co.,Ltd., Beijing, China;2. College of Pipeline and Civil Engineering of China University of Petroleum (East China), Qingdao, Shandong, China
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Abstract: |
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. |
Key words: natural gas hydrate ammonia methane carbon dioxide replacement molecular dynamics |