Reducing the deactivation of Ni-metal during the catalytic partial oxidation of a surrogate diesel fuel mixture

• Published in: Catalysis today Vol. 154; no. 3; pp. 210 - 216
• Main Authors: Haynes, Daniel J., Campos, Andrew, Smith, Mark W., Berry, David A., Shekhawat, Dushyant, Spivey, James J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15-09-2010; Elsevier
• Subjects: Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Hexaaluminate; Logistic fuel reforming; Nickel; Partial oxidation catalyst; Pyrochlore; Pyrochlore Hexaaluminate Nickel Logistic fuel reforming Partial oxidation catalyst; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Pyrochlore; Partial oxidation catalyst; Nickel; Hexaaluminate; Logistic fuel reforming; XANES spectrometry; Perovskite type compound; Support; Diesel fuel; Reforming; High temperature; Synthesis gas; Pyrochlore type compound; Supported catalyst; Characterization; Chemical reduction; Defect; Sulfur; Structure; Deposition; Catalytic reaction; Deactivation; Hydrocarbon; Transition metal; Carbon; Conversion; X ray diffraction; Partial oxidation; Vaporization; Heterogeneous catalysis; Sintering; Fuel; Alumina; Catalyst
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2010.03.072

Ni catalysts are active and selective for the conversion of hydrocarbon into synthesis gas. However, conventional supported Ni catalysts rapidly deactivate at the high temperatures required for partial oxidation of diesel fuel by sintering and metal vaporization, as well as by carbon deposition and sulfur poisoning. Thus, to reduce deactivation Ni (3
wt%) was substituted into the structures of Ba-hexaaluminate (BNHA) and La–Sr–Zr pyrochlore (LSZN), and their activity was compared to a supported Ni/Al
2O
3 for the catalytic partial oxidation (CPOX) of a surrogate diesel fuel. Characterization by XRD showed a single phase β-alumina for the hexaaluminate, while LSZN had a pyrochlore structure with a defect SrZrO
3 perovskite phase. Temperature programmed reduction experiments confirmed Ni was reducible in all catalysts. XANES results confirmed that Ni atoms were substituted into the hexaaluminate and pyrochlore structures, as spectra for each catalyst showed different coordination environments for Ni compared to a NiO standard. During CPOX activity tests (
T
=
900
°C and WHSV
=
50,000
scc/g
cat/h), the LSZN pyrochlore produced stable H
2 and CO yields in the presence of 5
wt% 1-methylnaphthalene and 50
ppmw dibenzothiophene/n-tetradecane for 2
h, while both Ni/Al
2O
3 and BNHA catalysts were irreversibly deactivated by this mixture over the same time. Activity loss was strongly linked to carbon formation.