Y. F. Guo, C. W. Zhao and C. H. Li (2015) Thermogravimetric analysis of carbonation behaviors of several potassium-based sorbents in low concentration CO2. Journal/Journal Of Thermal Analysis And Calorimetry 119 441-451. [In English]
Web link: http://dx.doi.org/10.1007/s10973-014-4207-3
Keywords: CO2 removal, Potassium-based sorbent, Reaction condition, Thermogravimetric analysis, FLUIDIZED-BED REACTOR, SEPARATION TECHNOLOGY, LOW-TEMPERATURES, N2O, PRECURSORS, DRY SORBENTS, CAPTURE, CAO, PYROLYSIS, DIOXIDE, BIOMASS
Abstract: Thermogravimetric analysis is finding increasing utility in investigations of reaction paths and carbonation behaviors of CO2 sorbent. Potassium-based sorbents are currently suggested as new options for capturing CO2 from flue gas after combustion or removing CO2 from confined space, such as submarines, space crafts, and air-crafts. In this paper, K2CO3/AC, K2CO3/Al2O3, K2CO3/5A, K2CO3/13X, and K2CO3/SG were prepared with the impregnation of K2CO3 on activated carbon (AC), Al2O3, zeolite 5A, zeolite 13X, and silica aerogels (SG), respectively. The carbonation paths and behaviors of these sorbents in low temperature and CO2 concentration were revealed with TG. The carbonation conversions and average reaction rates were measured under different conditions by changing support material, temperature, CO2 concentration, and H2O concentration. The carbonation conversions for K2CO3/AC, K2CO3/Al2O3, K2CO3/5A, K2CO3/13X, and K2CO3/SG are 93.3, 67.3, 34.5, 60.0, and 10.1 %, respectively. The reaction paths of K2CO3/AC and K2CO3/SG are found out that the hydration reaction occurs first to form K2CO3 center dot 1.5H(2)O and K4H2(CO3)(3)center dot 1.5H(2)O, then KHCO3 is produced rapidly. In the case of K2CO3/Al2O3, K2CO3/5A, and K2CO3/13X, a new phase of KAl(CO3)(2)(OH)(2) is formed which requires a higher temperature of 350 degrees C to be decomposed. The carbonation conversions increase with the increase of the CO2 concentration and H2O concentration, but decrease with the increase of temperature. The average reaction rate increases when the aforementioned variables increase to a high value. The support material is the key factor that affects the carbonation conversion and average reaction rate. Choosing a proper support material is most important for obtaining enhanced CO2 capture capacity of potassium-based sorbent.

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