调控氧传输以实现甲烷化学链部分氧化表面和体相速率的匹配
Achieving surface and bulk rate matching for chemical looping partial oxidation of methane by modulating oxygen transport
杨婷婷 1罗冉 1石向成 2张先华 1吴仕灿 1裴春雷 1赵志坚 3巩金龙4
作者信息
- 1. Key Laboratory for Green Chemical Technology of Ministry of Education,School of Chemical Engineering & Technology,Tianjin University;Collaborative Innovation Center of Chemical Science and Engineering,Tianjin 300072,China
- 2. Key Laboratory for Green Chemical Technology of Ministry of Education,School of Chemical Engineering & Technology,Tianjin University;Collaborative Innovation Center of Chemical Science and Engineering,Tianjin 300072,China;Department of Chemistry,National University of Singapore,Science Drive 3,Singapore 117543,Republic of Singapore
- 3. Key Laboratory for Green Chemical Technology of Ministry of Education,School of Chemical Engineering & Technology,Tianjin University;Collaborative Innovation Center of Chemical Science and Engineering,Tianjin 300072,China;Haihe Laboratory of Sustainable Chemical Transformations,Tianjin 300192,China;National Industry-Education Platform of Energy Storage,Tianjin University,Tianjin 300350,China
- 4. Key Laboratory for Green Chemical Technology of Ministry of Education,School of Chemical Engineering & Technology,Tianjin University;Collaborative Innovation Center of Chemical Science and Engineering,Tianjin 300072,China;Haihe Laboratory of Sustainable Chemical Transformations,Tianjin 300192,China;National Industry-Education Platform of Energy Storage,Tianjin University,Tianjin 300350,China;Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Fu
- 折叠
摘要
甲烷化学链部分氧化(CL-POM)是一种有前景的合成气生产技术,具有高选择性和低爆炸风险的优势.然而,开发性能优异、可持续释氧的金属载氧体仍然面临挑战.为此,本研究设计了一种复合载氧体(LaFeO3-δ/Ca1-ηSrηMnO3),通过调控Ca1-ηSrηMnO3的氧扩散来维持LaFeO3-δ(121)缺陷表面的活性结构,从而提升了CL-POM的活性和选择性.理论计算结果表明,甲烷在LaFeO3-δ(121)缺陷表面上的反应活性位点主要是Fe-O4(Ov)和Fe-O3(Ov)2,它们表现出相近的反应能垒(ΔGa=1.44和1.40 eV).氧扩散系数和表面反应速率常数分别由体相氧迁移能垒和表面反应能垒确定,进而计算得到体相氧扩散和表面反应的速率,用以评估两者的匹配程度.最后,本研究证实了LaFeO3-δ/Ca0.75-Sr0.25MnO3是一种有潜力的CL-POM载氧体,其能够实现体相氧扩散速率与表面氧消耗速率的合理匹配,并有效地抑制不利的相变过程.
Abstract
Chemical looping partial oxidation of methane(CL-POM)offers a promising approach to produce syngas with high selectivity and reduced explosion risk.However,the design of metal oxide oxygen carriers with excellent perfor-mance and continuous oxygen release capacity remains a challenge.In this study,we developed a composite oxygen carrier(LaFeO3-δ/Ca1-ηSrηMnO3)with the aim of modulating the oxygen transport capacity of Ca1-ηSrηMnO3 to maintain active structures on the LaFeO3-δ(121)defected surface,thereby enhancing the activity and selectivity of CL-POM.The Fe-O4(Ov)and Fe-O3(Ov)2 local structures were found to serve as active sites for methane oxidation on the LaFeO3-δ(121)defected surface,with comparable free energy barriers of re-action(AGa=1.44 and 1.40 eV,respectively).Based on the oxygen migration energy barriers and reaction energy barriers calculated by DFT,we determined oxygen transport coeffi-cients and surface reaction rate constants to further assess the degree of rate matching between bulk oxygen transport and surface oxygen consumption.Finally,LaFeO3-δ/Ca0.75Sr0.25-MnO3 was proposed as a potential candidate for CL-POM.This composite material achieves commendable rate matching between surface reactivity and bulk oxygen transport,and notably exhibits the highest phase transition energy barrier,effectively inhibiting adverse phase transitions.
关键词
chemical looping technique/partial oxidation of methane/steady-state approximation/oxygen transport capacity/rate matchKey words
chemical looping technique/partial oxidation of methane/steady-state approximation/oxygen transport capacity/rate match引用本文复制引用
基金项目
国家重点研发计划(2022YFE0102000)
国家自然科学基金(22121004)
国家自然科学基金(U22A20409)
Haihe Laboratory of Sustainable Chemical Transformations,the Program of Introducing Talents of Discipline to Universities(BP0618007)
XPLORER Prize()
generous computing resources at High Performance Computing Center of Tianjin University()
出版年
2024
NETL
NSTL
万方数据