Repetitive Carbonation-Calcination Reactions of Ca-Based Sorbents for Efficient CO2 Sorption at Elevated Temperatures and Pressures

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• 作者：Koji Kuramoto ; Shinji Fujimoto ; Atsuko Morita ; Sayaka Shibano ; Yoshizo Suzuki ; Hiroyuki Hatano ; Lin Shi-Ying ; Michiaki Harada ; and Takayuki Takarada
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2003
• 出版时间：March 5, 2003
• 年：2003
• 卷：42
• 期：5
• 页码：975 - 981
• 全文大小：356K
• 年卷期：v.42,no.5(March 5, 2003)
• ISSN：1520-5045

文摘

In an effort to develop a novel hydrogen production process in which coal is gasified with high-pressure steam in the presence of CO₂ sorbents, the fundamental CO₂ sorption characteristicsof Ca-based sorbents during repetitive carbonation-calcination reactions at different pressureswere investigated using a conventional TG/DTA analyzer and a laboratory-scale horizontal-tube reactor. The results revealed that, as a result of sintering and crystal growth, Ca-basedsorbents were significantly deactivated by high-temperature calcination treatment. As aconsequence, the CO₂ uptake capacity of the sorbents decreased with cycle number under bothatmospheric and pressurized conditions. An intermediate hydration treatment was found toenhance the reactivity and durability of the sorbents for multicycle CO₂ sorption. Because ofthe presence of eutectics in the CaO-Ca(OH)₂-CaCO₃ ternary system, the formation of sorbentmelts was observed in repetitive calcination-hydration-carbonation reactions at elevatedpressures at 923 and 973 K. Even under eutectic conditions, the sorbents retained their highreactivity for CO₂ sorption.