A critical issue in the burning of solid carbon fuels is the release of CO2, a greenhouse gas. Chemical looping combustion employs a metal oxide as oxygen carrier, thereby enabling only CO2 as the only gaseous product and mitigating the need for separation from N2. This leads to questions of the nature by which oxidation of solid carbon with an oxygen carrier takes place, and what criterion can be employed in choosing an appropriate oxygen donor. In this paper, doped Bi2O3 were synthesized as oxygen carriers for chemical looping combustion (CLC) of carbon black. The crystal structures of carbon/doped Bi2O3 mixture in the redox reaction were in-situ measured by synchrotron X-ray diffraction (SXRD), as a means to determine the reaction kinetics. Heating rates were varied to determine the activation energy for the carbon/doped Bi2O3 reaction. Results show that lower metal-oxygen bond energy and higher oxygen vacancy concentration of doped Bi2O3 led to lower onset temperature, smaller activation energy and higher reaction rate of carbon/doped Bi2O3 redox reaction. These results provide important insights into manipulating metal oxides’ atomic properties for energetic application.

Study of C/doped δ-Bi2O3 oxidation in chemical-looping combustion by in situ synchrotron X-ray diffraction

254th National Meeting (2017)

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