天然气工业2024，Vol.44Issue(2)：188-196,9.DOI:10.3787/j.issn.1000-0976.2024.02.018
温和条件下甲烷提高水合物储氢稳定特性机理
Mechanism of methane in improving the stability of hydrate hydrogen storage under mild conditions
摘要
Abstract
Methane as an accelerator can significantly reduce the harsh thermodynamic conditions of hydrogen storage in hydrates and increase the total energy storage density of hydrogen hydrate.At present,however,the mechanisms of methane in improving hydrate hydrogen storage have not been understood.In this paper,the CH4/H2 double-guest molecular hydrate model is established by virtue of molecular dynamics simulation.Then,the stability of hydrate structure at different temperatures and pressures is comprehensively analyzed by means of radial distribution function,conformation analysis and mean square displacement.Finally,the relationships between the position and proportion of H2 occupied holes and the thermodynamic stability of hydrate are explored,and the microscopic mechanism of methane promoting hydrogen storage in hydrate under mild conditions is revealed.And the following research results are obtained.First,the cage structure of pure hydrogen hydrate is seriously damaged under harsh conditions,while pure methane hydrate can remain stable at 263-273 K and 5-20 MPa,indicating that methane hydrate has good thermodynamic stability.Second,the hydrogen storage structure is more stable at 263 K,while the 512 small cage can be filled with 1 to 2 H2 molecules,and the 51262 large cage can optimally store 3 H2 molecules.The hydrogen storage structure of the large cage has a great influence on the stability of the hydrate and is more sensitive to temperature.In conclusion,the CH4/H2 hydrate hydrogen storage systems 3L+2S,3L+2L and 2S+2S perform better under the mild conditions of 263 K and 15-20 MPa.And among them,the system 3L+2S is the best in thermodynamic stability with the hydrogen storage density of 0.301%(mass fraction).The research results can provide theoretical guidance and technological reference for the development of hydrate hydrogen storage technology.关键词
氢气水合物/甲烷/储氢技术/储氢密度/分子动力学/储氢机理/稳定性Key words
Hydrogen hydrate/Methane/Hydrogen storage technology/Hydrogen storage density/Molecular dynamics/Hydrogen storage mechanism/Stability引用本文复制引用
王芳,穆金池,张政,黄泽皑,郭利红,周莹..温和条件下甲烷提高水合物储氢稳定特性机理[J].天然气工业,2024,44(2):188-196,9.基金项目
国家自然科学基金项目"定向调控甲烷活化生成抗积碳中间体提升Ni/CeO2 光热催化甲烷干重整性能研究"(编号:22209136)、四川省自然科学基金项目"油水乳液/低维纳米流体水合物促进剂用于甲烷制合成氨脱碳关键技术"(编号:2023NSFSC0108)、四川省重点研发项目"功能化碳纳米管阵列快速捕获分离CO2 关键技术"(编号:2022YFSY0050). （编号:22209136）
