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Reduction and oxidation kinetics of Co-Ni/Al2O3 oxygen carrier involved in a chemical-looping combustion cycles

Research output: Contribution to journalArticlepeer-review

121 Scopus citations

Abstract

The solid-state kinetics of Co-Ni/Al2O3 oxygen carrier is studied using non-isothermal reaction data and a non-linear regression analysis. XRD analysis of the fresh samples shows that NiO is the dominant reducible phase of the oxygen carrier. Pulse chemisorption suggests a negligible nuclei growth over the repeated reduction/oxidation cycles. Mercury porosimetry confirms that the pore size of the carrier particle is slightly increased following reduction. A nucleation and nuclei growth model and an unreacted shrinking-core model are developed based on the oxygen carrier texture change during reduction/oxidation, as observed by pulse chemisorption and mercury porosimetry. Model parameters are calculated using H2-TPR and O2-TPO data. It is found that the random nucleation model describes solid phase changes adequately. The determined apparent activation energies are 45 and 44 kJ/mol for the reduction and oxidation, respectively. The established kinetic model is successfully evaluated for the reduction cycle using a CREC mini-fluidized Riser Simulator reactor operating under expected conditions of large industrial scale fluidized CLC units.

Original languageEnglish
Pages (from-to)98-106
Number of pages9
JournalChemical Engineering Science
Volume65
Issue number1
DOIs
StatePublished - 2010
Externally publishedYes

Bibliographical note

Funding Information:
M.M.H. wishes to acknowledge the Natural Sciences and Engineering Research Council of Canada (NSERC) for Canada Graduate Scholarship for Doctoral study (CGS-D) and The University of Western Ontario for President's Scholarship for Graduate Study (PSGS). The authors also like to thank NSERC for their financial support to this project.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

  1. SDG 13 - Climate Action
    SDG 13 Climate Action

Keywords

  • CLC
  • CO capture
  • Gas-solid reaction kinetics
  • Nucleation and nuclei growth model
  • Shrinking-core model

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering

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