Characterization and evaluation of synthetic Dawsonites as CO2 sorbents
Characterization and evaluation of synthetic Dawsonites as CO2 sorbents
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DOI：
10.1016/j.fuel.2018.09.057
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发表时间：
2019-01
期刊：
影响因子：
7.4
通讯作者：
F. Lundvall;G. Kalantzopoulos;D. Wragg;B. Arstad;R. Blom;A. Sjåstad;H. Fjellvåg
中科院分区：
文献类型：
--
作者：
F. Lundvall;G. Kalantzopoulos;D. Wragg;B. Arstad;R. Blom;A. Sjåstad;H. Fjellvåg
吸附剂强化水煤气变换 (SEWGS) 工艺在二氧化碳捕集方面具有巨大潜力，因此是通过气体排放洗涤进行传统燃烧后捕集的现实替代方案。然而，需要性能更好的材料才能使 SEWGS 与最先进的洗涤技术竞争。片钠铝石，NaAl(OH)2CO3，具有高碳酸盐含量，并且在碱金属促进的氧化铝上原位捕获 CO2 时形成，从而在可变温度捕获过程中显示出潜力。对于等温 SEWGS 工艺，变压吸收性能至关重要。我们根据原位 X 射线衍射、热重分析和质谱联用、魔角旋转核磁共振波谱以及等温条件下的高压固定床反应器测试的数据，评估合成道铝石 [MAl(OH)2CO3,M=K, Na] 作为 SEWGS 工艺的 CO2 吸附剂。结果表明，与碱金属促进的水滑石相比，合成道铝石是 SEWGS 过程中很有前途的吸附剂，但其具有中等的循环 CO2 容量（∼0.3–0.7mmolCO2/吸附剂）。另一方面，这些材料在低温（280-310°C）下表现出相对较快的吸附速率，有利于 SEWGS 过程中的水煤气变换反应。
The sorbent enhanced water-gas shift (SEWGS) process has great potential for CO2capture and is thereby a realistic alternative to conventional post-combustion capture by gas emission scrubbing. Nevertheless, better performing materials are required to make SEWGS competitive against state-of-the-art scrubbing technologies. Dawsonite, NaAl(OH)2CO3, has a high carbonate content and formsin situduring CO2capture on alkali metal promoted alumina, thereby showing potential in variable temperature capture processes. For the isothermal SEWGS process the performance in pressure swing absorption is essential. We evaluate here synthetic Dawsonites [MAl(OH)2CO3,M= K, Na] as CO2sorbents for the SEWGS process based on data fromin situX-ray diffraction, combined thermogravimetric analysis and mass spectrometry, magic-angle spinning nuclear magnetic resonance spectroscopy, as well as high pressure fixed bed reactor tests at isothermal conditions. The results show that synthetic Dawsonites are promising sorbents for the SEWGS process, however, with moderate cyclic CO2capacities (∼0.3–0.7 mmol CO2/g sorbent) in comparison to alkali-metal promoted hydrotalcites. On the other hand, the materials exhibit relatively fast sorption rates at low temperatures (280–310 °C), favoring the water-gas shift reaction in the SEWGS process.