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X-ray absorption, X-ray diffraction and electron microscopy study of spent cobalt based catalyst in semi-commercial scale Fischer-Tropsch synthesis

Abstract

Calcined, reduced and spent Co-Re/γ-Al2O3 catalysts for Fischer–Tropsch synthesis (FTS) were characterized and compared. Co-K-edge and Re-LIII-edge X-ray absorption near edge structure (XANES), X-ray powder diffraction (XRPD), transmission electron microscopy (TEM) and H2 chemisorption were used to provide insight into structural transformations that the catalyst experiences during a month of operation in a semi-commercial FTS plant. Results from the core techniques for nanoparticle size determination suggest that sintering of the cobalt crystallites is an important deactivation mechanism in FTS performed in slurry reactors. In addition, a higher degree of reduction is observed for the spent catalytic material, while Re appears in a partially reduced state before and after reaction. The particle size distribution together with the spread of Co nanoparticles on the γ-Al2O3 surface indicates crystallite migration as the prevailing mechanism.

Category

Academic article

Language

English

Author(s)

  • Nikolaos Tsakoumis
  • Roya Dehghan-Niri
  • Magnus Rønning
  • John Walmsley
  • Øyvind Borg
  • Erling Rytter
  • Anders Holmen

Affiliation

  • Norwegian University of Science and Technology
  • SINTEF Industry / Materials and Nanotechnology
  • Equinor

Year

2014

Published in

Applied Catalysis A : General

ISSN

0926-860X

Publisher

Elsevier

Volume

479

Page(s)

59 - 69

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