MgAl2O4 Spinel-Stabilized Calcium Oxide Absorbents with Improved Durability for High-Temperature CO2 Capture
MgAl2O4 Spinel-Stabilized Calcium Oxide Absorbents with Improved Durability for High-Temperature CO2 Capture
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DOI：
10.1021/ef100245q
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发表时间：
2010-05
期刊：
影响因子：
5.3
通讯作者：
Liyu Li;D. King;Z. Nie;Xiaohong Li;C. Howard
中科院分区：
文献类型：
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作者：
Liyu Li;D. King;Z. Nie;Xiaohong Li;C. Howard
在有效的能量回收的情况下，在高温下操作的基于氧化钙的吸收剂比在较低温度下操作的吸收剂具有从燃煤电厂捕获CO2的优势。这些吸收剂的主要限制是CaO和CaCO 3的碳酸化和脱碳反应远不是完全的或可逆的。由于严重的吸收剂烧结，在许多碳酸化/脱碳循环中总是观察到CO2容量的快速损失。我们发现，适当地混合氧化钙前驱体和小棒状的MgAl 2 O 4尖晶石纳米颗粒可以有效地减轻这种烧结效应。通过将纳米镁铝尖晶石颗粒与醋酸钙进行湿法物理混合，再经高温煅烧，制备出了一类高温稳定性得到显著改善的新型CaO基吸收剂。CaO-MgAl 2 O 4（尖晶石含量为32 wt %）材料在65次碳酸化-脱碳循环（分别为650和850 °C）后提供34 wt %的CO2容量，对应于63%的CaO使用。在相同的试验条件下，天然白云石（35wt%MgO和65wt%CaO）的CO2容量从第1次循环的25wt%迅速下降到第50次循环的5wt%以下。
With efficient energy recovery, calcium-oxide-based absorbents that operate at elevated temperatures have an advantage over absorbents that operate at lower temperatures for CO 2 capture from coal power plants. The major limitation of these absorbents is that the carbonation and decarbonation reactions of CaO and CaCO 3 are far from complete or reversible- Rapid loss of CO 2 capacity over many carbonation/ decarbonation cycles is always observed because of severe absorbent sintering. We have found that this sintering effect can be effectively mitigated by properly mixingcalcium oxide precursors with small rod-like MgAl 2 O 4 spinel nanoparticles. A new class of CaO-based absorbents with much improved high-temperature durability was developed by wet physical mixing of calcium acetate with nano MgAl 2 O 4 spinel particles followed by high-temperature calcination. CaO-MgAl 2 O 4 (32 wt % spinel content) material provides 34 wt % CO 2 capacity after 65 carbonation-decarbonation cycles (650 and 850 °C, respectively), corresponding to 63% CaO use. Under the same test conditions, the CO 2 capacity of natural dolomite (35 wt % MgO and 65 wt % CaO) decreases rapidly from 25 wt % for the 1st cycle to less than 5 wt % for the 50th cycle.