Characterization and Performance in a Multicycle Test in a Fixed-Bed Reactor of Silica-Supported Copper Oxide as Oxygen Carrier for Chemical-Looping Combustion of Methane
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- 作者：B. M. Corbella ; L. De Diego ; F. Garcí ; a ; J. Adá ; nez ; and J. M. Palacios
- 刊名：Energy & Fuels
- 出版年：2006
- 出版时间：January 2006
- 年：2006
- 卷：20
- 期：1
- 页码：148 - 154
- 全文大小：353K
- 年卷期：v.20,no.1(January 2006)
- ISSN：1520-5029
文摘
Chemical-looping combustion of carbonaceous compounds is a proposed two-step process for completeCO2 capture and substantial reduction of NOx emissions. In the first stage, the reduction stage, the frameworkoxygen of a reducible inorganic oxide is used for the combustion of the carbonaceous material. In the secondstage, the regeneration stage, the carrier in a reduced state is regenerated with air to recover the properties ofthe fresh carrier, ready to reinitiate a new cycle. This article provides results for the performance of a copperoxide silica-supported oxygen carrier in a 20-cycle test of chemical-looping of methane in a fixed-bed reactorat 800 
C and atmospheric pressure. The mesoporous nature of silica provided a good dispersion of the activephase imparting a high mechanical strength to the overall carrier. Additionally, silica is stable under highlyreducing agents and inert in the two involved processes. The respective CH4, CO2, and CO breakthroughcurves in the reduction stage show that the reduction reaction rate is fast and highly selective to CO2 formation.CO emissions are very low, only yielded at the end of the reduction stage, when the reduction stage should bestopped to initiate a regeneration stage. Characterization studies using different techniques, such as TPR, SEM-EDX, and powder XRD, reveal that CuO might decompose into Cu2O at the operating conditions used in thereduction stage, but fortunately, the decomposition rate is so low that it has no effect on the oxygen amountinitially available for chemical-looping combustion. Copper does not promote the thermal decomposition ofmethane, and deposited carbon, consequently, could not be detected in the reduced carrier. In a 20-cycle testneither performance decay nor mechanical degradation of the oxygen carrier has been observed.
C and atmospheric pressure. The mesoporous nature of silica provided a good dispersion of the activephase imparting a high mechanical strength to the overall carrier. Additionally, silica is stable under highlyreducing agents and inert in the two involved processes. The respective CH4, CO2, and CO breakthroughcurves in the reduction stage show that the reduction reaction rate is fast and highly selective to CO2 formation.CO emissions are very low, only yielded at the end of the reduction stage, when the reduction stage should bestopped to initiate a regeneration stage. Characterization studies using different techniques, such as TPR, SEM-EDX, and powder XRD, reveal that CuO might decompose into Cu2O at the operating conditions used in thereduction stage, but fortunately, the decomposition rate is so low that it has no effect on the oxygen amountinitially available for chemical-looping combustion. Copper does not promote the thermal decomposition ofmethane, and deposited carbon, consequently, could not be detected in the reduced carrier. In a 20-cycle testneither performance decay nor mechanical degradation of the oxygen carrier has been observed.