Carbonation and Hydration Characteristics of Dry Potassium-Based Sorbents for CO2 Capture
Carbonation and Hydration Characteristics of Dry Potassium-Based Sorbents for CO2 Capture
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DOI：
10.1021/ef800889m
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发表时间：
2009-02
期刊：
影响因子：
5.3
通讯作者：
Chuanwen Zhao;Xiaoping Chen;Changsui Zhao;Yakun Liu
中科院分区：
文献类型：
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作者：
Chuanwen Zhao;Xiaoping Chen;Changsui Zhao;Yakun Liu
利用热重分析仪（TGA）和X射线衍射仪（XRD）研究了钾基吸收剂的CO2捕集特性。K2CO3·1.5H2O和由K2CO3·1.5H2O脱水得到的K2CO3的碳酸化反应性较弱。然而，从KHCO3煅烧的K2CO3显示出优异的碳酸化能力，并且在多个循环期间不会使吸附剂失活。XRD结果表明，K2CO3·1.5H2O脱水后的样品为单斜晶体结构的K2CO3（PC#1）。PC#1的碳酸化产物包括K2CO3·1.5H2O和KHCO3，其中K2CO3·1.5H2O是主要产物。相应地，具有六方晶体结构的K2CO3（PC#2）是由KHCO3煅烧的产物，并且PC#2的主要碳酸化产物是KHCO3。PC#2的副产物K4H2（CO3）3·1.5H2O会影响碳酸化过程。水化实验证实了两个假设：单斜晶体结构的K2CO3首先发生水化反应，碳酸盐化反应首先发生在单斜晶体结构的K2CO3。
Thermogravimetric apparatus (TGA) and X-ray diffraction (XRD) have been used to study the characteristics of potassium-based sorbents for CO2 capture. The carbonation reactivity of K2CO3·1.5H2O and K2CO3 dehydrated from K2CO3·1.5H2O was weak. However, K2CO3 calcined from KHCO3 showed excellent carbonation capacity and no deactivation of sorbents during multiple cycles. The XRD results showed that the sample dehydrated from K2CO3·1.5H2O was K2CO3 with structure of monoclinic crystal (PC#1). The carbonation products of PC#1 included K2CO3·1.5H2O and KHCO3, and K2CO3·1.5H2O was the main product. Correspondingly, K2CO3 with structure of hexagonal crystal (PC#2) was the product calcined from KHCO3, and the main carbonation product of PC#2 was KHCO3. The byproduct of K4H2(CO3)3·1.5H2O for PC#2 would affect the carbonation processes. Hydration tests confirmed the two hypotheses: the hydration reaction will first occur for K2CO3 with structure of monoclinic crystal, and the carbonation reaction will first occur f...