Kinetics of the Oxidation of a Co-precipitated Mixture of Cu and Al2O3 by O2 for Chemical-Looping Combustion
Kinetics of the Oxidation of a Co-precipitated Mixture of Cu and Al2O3 by O2 for Chemical-Looping Combustion
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DOI：
10.1021/ef1002167
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发表时间：
2010-07-01
期刊：
影响因子：
5.3
通讯作者：
Scott, S. A.
中科院分区：
文献类型：
--
作者：
Chuang, S. Y.;Dennis, J. S.;Scott, S. A.
CuO和Al 2 O3的共沉淀混合物是用于化学链燃烧的良好氧载体，CuO + CO -> Cu + CO2。在300 - 750 ℃下测量了这种还原的氧载体（粒径为355-500 μ m）通过O-2再生的动力学。注意确保这些测量不受床和取样系统中的相间质量传递或气体混合的影响。相对于O-2的反应顺序被认为是近似统一的，并且在随后的循环中的再生速率可以近似于第一个循环中的再生速率。低于600 ℃，还原的氧载体的氧化不完全。在600 ℃以上，氧化完全为CuO，并在相当大的程度上受到外部传质的控制。在这些较高温度下，再生涉及收缩核机制和两个连续步骤：2Cu + 1/2 O（2）-> Cu 2 O，Δ H-1073 K（0）= -167.3 kJ/mol（1）Cu 2 O + 1/2 O（2）-> 2CuO，Δ H-1073 K（0）= -131.5 kJ/mol（2）在900 ℃下，完全氧化的载体分解为Cu 2 O和O-2。
A co-precipitated mixture of CuO and Al2O3 is a good oxygen carrier for chemical-looping combustion in, e.g., CuO + CO -> Cu + CO2. The kinetics of regeneration of this reduced oxygen carrier (particle size of 355-500 mu m) by O-2 were measured from 300 to 750 degrees C. Care was taken to ensure that these measurements were not affected by interphase mass transfer or mixing of gases in the bed and sampling system. The order of reaction with respect to O-2 was found to be approximately unity, and the rates of regeneration in subsequent cycles could be approximated by those in the first. Below 600 degrees C, oxidation of the reduced oxygen carrier was incomplete. Above 600 degrees C, oxidation was complete to CuO and was controlled to a considerable extent by external mass transfer. At these higher temperatures, regeneration involved a shrinking core mechanism and the two consecutive steps:2Cu + 1/2O(2) -> Cu2O, Delta H-1073 K(0) = -167.3 kJ/mol (1)Cu2O + 1/2O(2) -> 2CuO, Delta H-1073 K(0) = -131.5 kJ/mol (2)At 900 degrees C, the fully oxidized carrier decomposed to Cu2O and O-2.