Kinetics and Mechanism of Direct Reaction between CO2 and Ca(OH)2 in Micro Fluidized Bed

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• 作者：Jian Yu ; Xi Zeng ; Guangyi Zhang ; Juwei Zhang ; Yin Wang ; Guangwen Xu
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：July 2, 2013
• 年：2013
• 卷：47
• 期：13
• 页码：7514-7520
• 全文大小：447K
• 年卷期：v.47,no.13(July 2, 2013)
• ISSN：1520-5851

文摘

Even at present it is still difficult to characterize the reaction between CO₂ and Ca(OH)₂ at high temperature and atmospheric pressure using traditional instruments such as thermogravimetric analyzer and differential scanning calorimeter. This study was devoted to characterizing such a reaction in a newly developed micro fluidized bed reaction analyzer (MFBRA) under isothermal conditions in the temperature range of 773鈥?023 K. The results indicated that the MFBRA has not only a good adaptability for characterizing the above-mentioned reaction but enables as well a new insight into the mechanism of the reaction. An obvious time delay was identified for the release of the formed steam (H₂O) in comparison with the onset of its CO₂ absorption, which might be attributed to the formation of an unstable intermediate product Ca(HCO₃)₂ in the reaction process between CO₂ and Ca(OH)₂. The activation energy for forming Ca(HCO₃)₂ was found to be about 40 kJ/mol, which is much lower than that of the reaction between CO₂ and CaO.