石油学报(石油加工) ›› 2020, Vol. 36 ›› Issue (6): 1140-1147.doi: 10.3969/j.issn.1001-8719.2020.06.004

• 化学链燃烧 • 上一篇    下一篇

化学链燃烧中H2S与CuFe2O4载氧体的反应机理

李钰,刘晶,刘丰,方瑞雪   

  1. 华中科技大学 煤燃烧国家重点实验室, 湖北 武汉 430074

  • 收稿日期:2020-07-01 修回日期:2020-09-14 出版日期:2020-11-25 发布日期:2020-12-02
  • 通讯作者: 刘晶,女,教授,博士,从事燃煤CO2减排,燃烧污染物控制等研究,E-mail:liujing27@mail.hust.edu.cn E-mail:liujing27@mail.hust.edu.cn
  • 作者简介:第一作者:李钰,男,博士,研究生,从事化学链燃烧研究,E-mail:liyu521@mail.hust.edu.cn
  • 基金资助:
    国家自然科学基金项目(51976071)资助

Interaction Mechanism Between H2S and CuFe2O4 Oxygen Carrier in Chemical-Looping Combustion

 LI Yu, LIU Jing, LIU Feng, FANG Ruixue   

  1.  State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2020-07-01 Revised:2020-09-14 Online:2020-11-25 Published:2020-12-02
  • Supported by:
     

摘要:

基于密度泛函理论和周期性结构模型,在分子水平上研究了化学链燃烧中H2S与CuFe2O4载氧体表面相互作用的微观反应机理。结果表明,H2S分子解离的SH、S和H基团倾向于吸附在O.1原子顶位上。H2S分子在CuFe2O4载氧体表面发生的反应主要包括3个步骤:H2S分子吸附、H2S脱氢和H2O分子形成。首先H2S吸附在CuFe2O4载氧体表面进而发生两步脱氢反应,随着反应的进行,产生的H2O分子从载氧体表面脱附,CuFe2O4载氧体表面的S基团发生迁移并填入氧空位形成硫化表面。其中H2O分子的形成需克服135.57 kJ/mol的反应能垒,为速控步骤。围绕Cu原子进行的反应路径是H2S与CuFe2O4载氧体表面反应的主要路径,与实验结果吻合。

关键词: 化学链燃烧, H2S, CuFe2O4, 复合载氧体;反应机理;密度泛函理论

Abstract:

Based on density function theory and periodic structural model, the interaction mechanism between H2S and CuFe2O4 surface was studied at the molecular level. The results show that SH, S and H species dissociated from H2S molecule tend to be adsorbed on the most active O.1 atom. The interaction between H2S and CuFe2O4 mainly consists of three steps: adsorption of H2S molecule, dehydrogenation of H2S, and H2O molecule formation. H2S molecule adsorbs on the CuFe2O4 surface firstly and then the two-step dehydrogenation of H2S occurs. As the reaction proceeds, H2O molecule desorbs form the CuFe2O4 surface, the S species migrates and fills in the oxygen vacancy to form vulcanized surface. The formation of H2O molecule is the rate-determining step with an energy barrier being 135.57 kJ/mol. The pathway concentrated on the surface Cu atom is the main reaction pathway between H2S and CuFe2O4, which is consistent with experimental results.

Key words: chemical-looping combustion; H2S, CuFe2O4, composite oxygen carrier, interaction, density functional theory

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