Lanthanum-promoted copper-based oxygen carriers for chemical looping combustion process
| Autor: | Houyin Zhao, Wei-Ping Pan, Song P. Sit, Yan Cao |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Journal of Thermal Analysis and Calorimetry. 116:1257-1266 |
| ISSN: | 1588-2926 1388-6150 |
| DOI: | 10.1007/s10973-013-3628-8 |
| Popis: | Copper-based oxygen carriers have high reactivity and favorable thermodynamic properties in the innovative chemical looping combustion (CLC), which results in the inherent capture of CO2. The major challenge of copper-based oxygen carriers is its low melting point and potential thermal sintering and agglomeration under high-temperature cyclic CLC operations. This study is to verify the beneficial use of a rare earth metal (lanthanum) additive in copper for the enhancements of thermal stability of copper-based oxygen carriers. In both the initial 50-cycle tests using TPR-TPO techniques (temperature-programmed reduction and oxidation, 800 °C) and further extended 840-cycle tests using the micro-reactor system, in over 50 cyclic Redox TPR-TPO tests, the lanthanum-promoted copper-based oxygen carrier showed the substantial resistance to the agglomeration. Thermal analysis studies were also extended into investigations of free oxygen releasing from copper-based oxygen carrier. Characterization of used oxygen carriers revealed the significant interaction between copper and its supporting material, Al2O3. The Al2O3-supported CuO seemed to indicate a slow release of oxygen. The formation of a new crystal phase (CuAl2O4), combining CuO and γ-Al2O3, may be a major reason for the stability of copper-based oxygen carrier and the slow oxygen release under oxygen uncoupling condition. The fresh and used oxygen carriers were further characterized by (1) Brunauer–Emmett–Teller for the pore structure analysis, (2) X-ray diffraction for crystal structure analysis, and (3) scanning electron microscopy for surface analysis. |
| Databáze: | OpenAIRE |
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