Influence of the encapsulation degree of Fe-0 active sites on performance of garnets for chemical looping partial oxidation of CH4
Zong, Teng 1Li, Lin 1Han, Yujia 1Wang, Chaojie 1Kang, Yu 2Tian, Ming 1Huang, Chuande 1Wang, Xiaodong1
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作者信息
1. Chinese Acad Sci
2. Max Planck Inst Chem Phys Solids
折叠
Abstract
It is of challenge to improve the coke resistance of Fe-based oxygen carriers (OC) due to the conflict of Fe-0 sites for CH4 activation but causing coke formation. The present work reported that carbon-tolerant of Y3Fe2Al3O12-T garnets (YFAO-T, T indicates calcination temperature) could be remarkably promoted by tuning calcination temperature for chemical looping partial oxidation of methane (CLPOM). This was because the encapsulation degree of Fe-0 (1-Fe-exposed(0)/Fe-total(0)) became larger with reduction from 19% to 79% due to decreased oxygen mobility leading to more surface oxygen-deficiency for YFAO-T calcined at higher temperature, which not only resulted in Fe-0 sites for CH4 activation but also accessible lattice oxygen of garnet shell for carbon oxidation formed on Fe-0 sites. Comparatively, the encapsulation of Fe-0 was destroyed leading to progressively naked Fe-0 with large particle size with reduction for YFAO-T calcined at lower temperature, which induced carbon deposition due to inaccessible lattice oxygen of garnets.
Key words
Chemical looping/Garnet/Encapsulation of metals/Carbon resistance/CH4 conversion/LATTICE OXYGEN REACTIVITY/SHELL REDOX CATALYST/HYDROGEN-PRODUCTION/SYNGAS PRODUCTION/IRON-OXIDE/METHANE/COMBUSTION/CARRIER/FE2O3/AL2O3/SELECTIVITY
NSTL
Elsevier