K2CO3-Modified Potassium Feldspar for CO2 Capture from Post-combustion Flue Gas

详细信息    查看全文

• 作者：Yafei Guo ; Changhai Li ; Shouxiang Lu ; Chuanwen Zhao
• 刊名：Energy & Fuels
• 出版年：2015
• 出版时间：December 17, 2015
• 年：2015
• 卷：29
• 期：12
• 页码：8151-8156
• 全文大小：404K
• ISSN：1520-5029

文摘

Capturing CO₂ from post-combustion flue gas is one of the major solutions to CO₂ abatement in global warming and climate change. Potassium-based solid sorbents are confirmed as promising means for this purpose. To dispose of the substantive flue gas, the CO₂ capture process should be cost-effective. In this work, a novel K₂CO₃/PF sorbent was prepared by impregnation of potassium carbonate (K₂CO₃) on potassium feldspar (PF). The synthesized sample was characterized by X-ray fluorescence (XRF), field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). The CO₂ sorption behaviors of K₂CO₃/PF were evaluated in a fixed-bed reactor in simulated flue gas composition of 60 掳C, 5% CO₂, and 10% H₂O. The sorbent regeneration behaviors were also investigated in a N₂ atmosphere at 550 掳C with a ramping rate of 10 掳C/min. Further insights were focused on the reaction pathway and multiple cycle behaviors of the sorbent in 10 CO₂ sorption鈥揹esorption tests. The CO₂ sorption capacity of K₂CO₃/PF is calculated as 1.74 mmol of CO₂/g. The reaction pathways are revealed as that NaAlSi₃O₈ and KAlSi₃O₈ in the support can be converted into NaAlCO₃(OH)₂, Al₂(Si₂O₅)(OH)₄, NaHCO₃, and KHCO₃ in a humid CO₂ atmosphere. The carbonation reaction of K₂CO₃ to form KHCO₃ also contributes considerably to the whole CO₂ sorption process. The sorbent regeneration process consists of three steps as the desorption of adsorbed CO₂ at 55 掳C, the decompositions of NaHCO₃ and KHCO₃ at 130 掳C, and the decompositions of NaAlCO₃(OH)₂ and Al₂(Si₂O₅)(OH)₄ at 550 掳C. Besides, the desired sorbent presents excellent regenerability and stability during 10 cyclic CO₂ sorption鈥揹esorption tests. Considering the high CO₂ working capacity, long-term stability, low cost of the supporting materials, and recycling of waste resources, K₂CO₃/PF can be considered as a new option for flue gas treatment.