High Temperature CO2 Sorption on Li2ZrO3 Based Sorbents

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• 作者：Chao Wang ; Binlin Dou ; Yongchen Song ; Haisheng Chen ; Yujie Xu ; Baozhen Xie
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：August 13, 2014
• 年：2014
• 卷：53
• 期：32
• 页码：12744-12752
• 全文大小：565K
• ISSN：1520-5045

文摘

In this study, the Li₂ZrO₃ based sorbents with different compositions were synthesized by the solid-state reaction method from the mixtures of Li₂CO₃, K₂CO₃ and ZrO₂. CO₂ sorption properties of Li₂ZrO₃ based sorbents were investigated by analyzing the phases and microstructure changes with the help of thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. The thermodynamic calculations were carried out based on the second law of thermodynamics. Li₂CO₃/K₂CO₃-doped Li₂ZrO₃ sorbent with the composition of 36.23 wt % Li₂CO₃, 55.12 wt % ZrO₂ and 8.65 wt % K₂CO₃ was considered to achieve excellent capability for high temperature CO₂ sorption and presented the maximum sorption rate at 525 掳C and 0.15 atm of CO₂ partial pressure. The sorbent kept rather stable for multicycles sorption and regeneration, and maintained its original capacity during 12 cycle processes. There were three distinct phases in the nonisothermal CO₂ sorption process while the main CO₂ sorption occurred during the second phase. An improved iterative Coats鈥揜edfern method was used to evaluate nonisothermal kinetics of the CO₂ sorption process, and the kinetic parameters were derived by the MATLAB model. The Fn n^th-order reaction model predicted accurately the main phases and differences in the activation energies and the frequency factors for different sorbents in the sorption phases corroborated different mechanism integral functions and reaction orders.