Abstract The sorbent enhanced water-gas shift (SEWGS) process has great potential for CO2 capture 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 forms in situ during CO2 capture 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 CO2 sorbents for the SEWGS process based on data from in situ X-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 CO2 capacities (∼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.

中文翻译：

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合成片钠铝石作为 CO2 吸附剂的表征和评价

摘要 吸附剂增强水煤气变换 (SEWGS) 工艺具有巨大的 CO2 捕集潜力，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相比具有竞争力。片钠铝石 NaAl(OH)2CO3 具有高碳酸盐含量，并在碱金属促进的氧化铝捕获 CO2 期间原位形成，因此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、组合热重分析和质谱分析的数据，评估合成的片钠铝石 [MAl(OH)2CO3, M = K, Na] 作为 SEWGS 过程的 CO2 吸附剂，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堆测试。结果表明，合成的片钠铝石是用于 SEWGS 过程的有前途的吸附剂，但与碱金属促进的水滑石相比，具有中等的循环 CO2 容量（~0.3-0.7 mmol CO2/g 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。