Carbonation Characteristics of Dry Sodium-Based Sorbents for CO2 Capture

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• 作者：Wei Dong ; Xiaoping Chen ; Ye Wu ; Chuanwen Zhao ; Cai LiangDaoying Liu
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：September 20, 2012
• 年：2012
• 卷：26
• 期：9
• 页码：6040-6046
• 全文大小：417K
• 年卷期：v.26,no.9(September 20, 2012)
• ISSN：1520-5029

文摘

Na₂CO₃ is one potential capture medium with the potential to decrease CO₂ emission. Carbonation characteristics of four sodium-based sorbents were studied using thermogravimetric analysis (TGA), X-ray diffraction, scanning electron microscopy, and nitrogen adsorption apparatuses. Results show that, in TGA tests (carbonation atmosphere of 15% CO₂ + 15% H₂O(g) + 70% N₂ and carbonation temperature of 333 K), sorbent Na₂CO₃ [analytical reagent (AR)] is impervious, while sorbent Na₂CO₃ calcined from NaHCO₃ (AR) reacts, mostly forming Na₅H₃(CO₃)₄ instead of NaHCO₃, corresponding to 72.87% conversion of Na₂CO₃ in about 140 min. With regard to the TGA tests of sorbent Na₂CO₃/Al₂O₃ and sorbent Na₂CO₃/Al₂O₃ calcined from NaHCO₃/Al₂O₃, only NaHCO₃ is generated and the carbonation conversions are both above 85% in about 55 min. The microstructure changes were observed to analyze the reaction mechanisms and carbonation characteristics. It is confirmed that, by loading active components on Al₂O₃, the microscopic structures can be significantly improved, contributing to the great improvement of carbonation characteristics of the latter two sorbents. On the other hand, there is little improvement of carbonation characteristics using NaHCO₃ as precursors for sorbents supported on Al₂O₃.