Thermochemistry of double carbonates in the K2CO3-CaCO3system

Navrotsky, Alexandra; Putnam, Robert L.; Winbo, Camilla; Rosén, Erik

doi:10.2138/am-1997-5-614

Cited by 24 publications

(17 citation statements)

References 8 publications

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“…Fairchildite K 2 Ca(CO 3 ) 2 represents an intermediate stage generated in the binary system K 2 CO 3 -CaCO 3 , together with polymorphous butschliite with transition temperature lower than 450°C (Navrotsky et al 1997). The sample HT3 after synthesis and drying process presents diffraction rays related to the crystallization of hydrotalcite, gibbsite and calcite phases (Figure 5(a)), the last generated by preferential formation of carbonate with respect to hydroxide, due to the use of Na 2 CO 3 as a precipitating agent.…”

Section: Xrd Bet and Bjh Sorbents Characterizationmentioning

confidence: 99%

CO2 Sorption-Enhanced Processes by Hydrotalcite-Like Compounds at Different Temperature Levels

Gallucci

Micheli

Barisano³

et al. 2015

International Journal of Chemical Reactor Engineering

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The aim of this work is to identify solid sorbents for CO 2 capture for coal and biomass syngas conditioning and cleaning by means of a sorption-enhanced reaction process. Hydrotalcite-like compounds (HTlcs) were synthesized with and without K 2 CO 3 impregnation. Samples were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) porosimetry after synthesis and after capture tests, respectively. Sorption and desorption tests were performed in a fluidized bed reactor, under cyclic conditions, at two different temperature levels: 350/450°C and 600/700°C. At low temperature only the Mg-Al HTlcs K promoted samples showed stability and sorption capacity comparable with literature values. On the other hand, results at high temperature indicate that the mixed Mg-Ca-Al HTlcs samples exhibit the best behavior with the highest sorption capacity (1.7 mmol CO2 /g) almost stable over 5 sorption/regeneration cycles; furthermore, addition of steam allowed increasing their reactivity by 70% compared to the dry value. This type of sorbent could be a promising candidate to prepare a bifunctional sorbent-catalyst for sorption-enhanced processes, taking place directly in the fluidized bed gasifier, or downstream the reactor for adjustment of gas composition before further conversion in gaseous energy carriers.

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Section: Xrd Bet and Bjh Sorbents Characterizationmentioning

confidence: 99%

CO2 Sorption-Enhanced Processes by Hydrotalcite-Like Compounds at Different Temperature Levels

Gallucci

Micheli

Barisano³

et al. 2015

International Journal of Chemical Reactor Engineering

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“…This value can be compared with the enthalpy of formation of the end-member carbonates determined from the following thermochemical cycle using literature values for the enthalpy of formation of carbonates[21][22][23] …”

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confidence: 99%

The structure and thermochemistry of K2CO3–MgCO3 glass

et al. 2019

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“…41,47 Simultaneously, the large mesopores and macropores are developed owing to the template particles (i.e., K 2 Ca(CO 3 ) 2 , K 2 Ca 2 (CO 3 ) 3 , and CaO), giving rise to a much less dense structure than that obtained in the presence of only CaCO 3 . 48,49 In this way, cornstalk carbons with a hierarchical pore structure, large SSA and high meso/micropore ratio were successfully prepared, which has been depicted in the BET results of CHPCs.…”

Section: Resultsmentioning

confidence: 94%