Enhancement of Ca‐Based Sorbent Multicyclic Behavior in Ca Looping Process for CO2 Separation
Enhancement of Ca‐Based Sorbent Multicyclic Behavior in Ca Looping Process for CO2 Separation
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DOI：
10.1002/ceat.200800525
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发表时间：
2009-04
影响因子：
2.1
通讯作者：
Yingjie Li;Changsui Zhao;Huichao Chen;Yi Liu
中科院分区：
文献类型：
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作者：
Yingjie Li;Changsui Zhao;Huichao Chen;Yi Liu
钙基吸附剂循环是电厂CO2捕集的一种创新方法。但随着煅烧/碳酸化循环次数的增加，钙基吸收剂的CO2捕集能力急剧衰减。为了提高钙链循环中吸收剂的CO2捕集能力，采用醋酸溶液对石灰石进行改性。在双固定床反应器中研究了改性石灰石与原始石灰石的循环碳酸化行为。改性石灰石在各循环中的循环碳酸化动力学均优于原石灰石。改性石灰石在640-660 °C碳化时达到最佳碳化转化率。乙酸改性改善了石灰石的长期性能，导致在100次循环后直接测量的转化率高达0.4，而原始石灰石在相同的反应条件下保持在小于0.1的转化率。改性石灰石煅烧产物的孔容和孔面积分布均优于原始石灰石煅烧产物。CO2分压对石灰石转化率的影响大于改性石灰石，这是由于二者孔结构特征的差异。原始石灰石的碳酸化转化率随粒径的增大而降低，而改性吸附剂粒径的变化对循环碳酸化行为没有明显影响。
The Ca-based sorbent looping cycle represents an innovative way of CO 2 capture for power plants. However, the CO 2 capture capacity of the Ca-based sorbent decays sharply with calcination/carbonation cycle number increasing. In order to improve the CO 2 capture capacity of the sorbent in the Ca looping cycle, limestone was modified with acetic acid solution. The cyclic carbonation behaviors of the modified and original limestones were investigated in a twin fixed-bed reactor system. The modified limestone possesses better cyclic carbonation kinetics than the original limestone at each cycle. The modified limestone carbonated at 640-660 °C achieves the optimum carbonation conversion. The acetic acid modification improves the long-term performance of limestone, resulting in directly measured conversion as high as 0.4 after 100 cycles, while the original limestone remains at a conversion of less than 0.1 at the same reaction conditions. Both the pore volume and pore area distributions of the calcines derived from the modified limestone are better than those derived from the original limestone. The CO 2 partial pressure for carbonation has greater effect on conversion of the original limestone than on that of the modified sorbent because of the difference in their pore structure characteristics. The carbonation conversion of the original limestone decreases with the increase in particle size, while the change in particle size of the modified sorbent has no clear effect on cyclic carbonation behavior.