Effects of the Adsorbent Preparation Method for CO2 Capture from Flue Gas Using K2CO3/Al2O3 Adsorbents

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• 作者：Surajit Sengupta ; Vinay Amte ; Rajeshwer Dongara ; Asit Kumar Das ; Haripada Bhunia ; Pramod Kumar Bajpai
• 刊名：Energy & Fuels
• 出版年：2015
• 出版时间：January 15, 2015
• 年：2015
• 卷：29
• 期：1
• 页码：287-297
• 全文大小：688K
• ISSN：1520-5029

文摘

The effect of the preparation method on the CO₂ adsorption capacity of K₂CO₃/Al₂O₃ adsorbents is examined. The multi-step impregnation (MI) method enables uniform dispersion of active species (K₂CO₃) in the broad macropores without blocking narrower mesopores. This facilitates higher loading of accessible K₂CO₃ for CO₂ adsorption and, hence, higher adsorption capacity. The single-step impregnation (SI) method suffers from blockage of narrower mesopores by excessive growth of K₂CO₃. This limits the CO₂ accessibility toward active species in the porous structure because of the formation of larger active species aggregates. For 50 wt % K₂CO₃/Al₂O₃ prepared by MI and SI methods, the maximum CO₂ adsorption capacity at CO₂ partial pressure of 8 kPa is found to be 3.12 and 2.1 mmol/g, respectively. The regeneration efficiency of 50MI and 50SI are observed to be nearly 65 and 56%, respectively, at 130 掳C in multi-cycle testing. The experimental data for CO₂ adsorption were described by the Langmuir isotherm, and the isosteric heat as a function of fractional coverage of the adsorbent was evaluated by means of the van鈥檛 Hoff equation. The isosteric heat showed a decreasing trend with an increase in the surface coverage of the adsorbent. From the results, it is concluded that the adsorbent prepared by the MI method shows better performance because of its tunable textural and morphological properties to achieve higher CO₂ adsorption capacity.