Investigation of CaO-CO₂ reaction kinetics by in-situ XRD using synchrotron radiation

Journal Article · Thu Feb 05 00:00:00 EST 2015 · Chem. Eng. Sci.

DOI:https://doi.org/10.1016/j.ces.2014.12.058· OSTI ID:1170013

Biasin, A.; Segre, C. U.; Salviulo, G.; Zorzi, F.; Strumendo, M. ^[1]

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1. Padova

In this work, in-situ synchrotron radiation x-ray powder diffraction (SR-XRPD), performed at the Advanced Photon Source (APS) facilities of the Argonne National Laboratory, was applied to investigate the CaO–CO₂ reaction. A set of CO₂ absorption experiments were conducted in a high temperature reaction capillary with a controlled atmosphere (CO₂ partial pressure of 1 bar), in the temperature range between 450 °C and 750 °C using CaO based sorbents obtained by calcination of commercial calcium carbonate. The evolution of the crystalline phases during CO₂ uptake by the CaO solid sorbents was monitored for a carbonation time of 20 min as a function of the carbonation temperature and of the calcination conditions. The Rietveld refinement method was applied to estimate the calcium oxide conversion during the reaction progress and the average size of the initial (at the beginning of carbonation) calcium oxide crystallites. The measured average initial carbonation rate (in terms of conversion time derivative) of 0.280 s^-1 (±13.2% standard deviation) is significantly higher than the values obtained by thermo-gravimetric analysis and reported thus far in the literature. Additionally, a dependence of the conversion versus time curves on the initial calcium oxide crystallite size was observed and a linear relationship between the initial CaO crystallite size and the calcium oxide final conversion was identified.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: National Science Foundation (NSF)
• OSTI ID: 1170013
• Journal Information: Chem. Eng. Sci., Vol. 127, Issue 05, 2015
• Country of Publication: United States
• Language: ENGLISH