石油学报(石油加工) ›› 2020, Vol. 36 ›› Issue (6): 1338-1346.doi: 10.3969/j.issn.1001-8719.2020.06.024

• 反应器设计运行模拟 • 上一篇    下一篇

化学链燃烧中燃料气体在CaSO4(010)表面吸附扩散特性的分子动力学模拟

侯封校1, 金晶1, 刘敦禹1, 寇学森1, 杨浩然1, 王永贞2   

  1. 1. 上海理工大学 能源与动力工程学院 上海市动力工程多相流与传热重点实验室,上海 200093;
    2. 临沂大学 土木工程与建设学院,山东 临沂 276000
  • 收稿日期:2020-07-01 修回日期:2020-08-21 出版日期:2020-11-25 发布日期:2020-12-02
  • 通讯作者: 金晶,女,教授,博士,从事清洁燃烧与污染物排放控制的研究,E-mail:alicejin001@163.com E-mail:alicejin001@163.com
  • 作者简介:第一作者:侯封校,男,博士研究生,从事清洁燃烧与污染物排放控制的研究,E-mail:mercatushou@outlook.com
  • 基金资助:
    国家自然科学基金项目(51976129,51706143),“十三五”国家重点研发计划项目(2017YFF0209800), 上海理工大学科技发展项目(2019KJFZ192)基金资助

Adsorption and Diffusion Characteristics of Gas Fuel on CaSO4(010) Surface for Chemical-Looping Combustion: Molecular Dynamics Simulations

HOU Fengxiao1, JIN Jing1, LIU Dunyu1, KOU Xuesen1, YANG Haoran1, WANG Yongzhen2   

  1. 1. Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China;
    2. School of Civil Engineering and Architecture, Linyi University, Linyi 276000, China
  • Received:2020-07-01 Revised:2020-08-21 Online:2020-11-25 Published:2020-12-02
  • Supported by:
     

摘要:

以CaSO4为载氧体,采用分子动力学研究了化学链燃烧中不同温度时CO在CaSO4(010)表面的吸附扩散特性,并在反应温度为1173 K时与CH4、H2在CaSO4(010)表面的吸附扩散特性对比。结果表明:CO在CaSO4(010)表面的吸附为物理吸附,吸附强度随温度升高而减弱,吸附层与体相层的分层点为距离CaSO4(010)表面0.66 nm处;CO在xy平面方向的扩散能力随温度升高而上升,符合分子碰撞理论; CO吸附于CaSO4(010)表面的原因主要为静电作用所造成的弱相互作用。与CH4、H2相比,CO在CaSO4(010)表面的吸附能力最强,吸附层中含量最多;H2在xy平面方向扩散能力最强,体相层中体积占比最大;而CH4较弱的静电作用与H2较强的位阻作用导致了二者在CaSO4(010)表面吸附能力弱于CO。研究结果可为钙基载氧体的改进与优化提供理论基础。

关键词: 硫酸钙载氧体, 化学链燃烧, 分子动力学, 吸附, 扩散, 弱相互作用

Abstract:

The molecular dynamics simulations were used to study the adsorption and diffusion characteristics of CO on the CaSO4(010) surface at different temperatures in chemical-looping combustion with CaSO4 oxygen carrier, and it was compared with CH4 and H2 at 1173 K. The results show that the adsorption of CO on CaSO4(010) surface is physical adsorption, and the intensity weakens with the temperature increasing. The delamination point between the adsorption layer and the bulk layer is 0.66 nm from the CaSO4(010) surface. The diffusivity of CO in xy plane direction increases with temperature increasing, which is consistent with molecular collision theory. Additionally, the weak interactions caused by the electrostatic effect is the main reason for the CO adsorption. Compared with the adsorption of CH4 and H2, the adsorption of CO on CaSO4(010) surface is the strongest, and the content of CO is the most in the adsorption layer. The diffusivity of H2 is the strongest in xy plane direction, and its volume ratio is the largest in the bulk layer, which is consistent with molecular collision theory and ideal gas kinetic theory. Moreover, the weak electrostatic effects of CH4 and the strong steric interactions of CH4 and H2 lead to the weak adsorption, which is lower than CO molecules, on the CaSO4(010) surface. The results offer the theoretical foundation to improve the calcium oxygen carriers.

Key words: calcium sulfate oxygen carrier, chemical-looping combustion, molecular dynamics, adsorption, diffusion, weak interaction

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