A crucial role of O2− and O22− on mayenite structure for biomass tar steam reforming over Ni/Ca12Al14O33

• Published in: Applied catalysis. B, Environmental Vol. 88; no. 3-4; pp. 351 - 360
• Main Authors: Li, Chunshan, Hirabayashi, Daisuke, Suzuki, Kenzi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.05.2009; Elsevier
• Subjects: Biomass tar; Catalysis; Chemistry; Coke-resistance; Exact sciences and technology; General and physical chemistry; Ni/Ca12Al14O33; Sulfur poisoning; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Toluene steam reforming; Biomass tar; Ni/Ca12Al14O33; Coke-resistance; Toluene steam reforming; Sulfur poisoning; Incorporation; Calcium; Destruction; Tar; Coke; Hydrogen sulfides; Ni/Ca; Biomass; Al; O; Chemical reduction; Model compound; Raman spectrometry; Sulfur; Structure; Activation energy; Oxygen; Reactivation; Hydrocarbon; Toluene; Fixed bed reactor; Aluminium; Cleaning; X ray diffraction; Resistance; Heterogeneous catalysis; Kinetic model; Benzenic compound; Nickel; Steam reforming; Alumina; Catalyst; Environmental protection
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2008.11.004

Newly synthesized nickel calcium aluminum catalysts (Ni/Ca12Al14O33) were tested in a fixed bed reactor for biomass tar steam reforming, toluene as tar destruction model compound. Four catalysts (Ni/Ca12Al14O33) were prepared with Ni loading amount from 1, 3, 5 to 7wt%, even 1% loading catalyst also showed excellent performance. Catalysts aged experiments in the absence (60h on stream) and presence of H2S were characterized by BET, X-ray diffraction (XRD), and Raman spectra. It was observed that Ni/Ca12Al14O33 showed excellent sustainability against coke formation due to the “free oxygen” in the catalysts. It also exhibited higher H2S-poisoning resistance property compared to the commercial catalysts Ni/Al2O3 (5%) and Ni/CaO0.5/MgO0.5. Raman spectra revealed that “free oxygen O2− and O22−” in the structure of the catalysts could be substituted by sulfur then protected Ni poisoning on some degree, but reactivation experiments by O2 flowing showed that the sulfide Ni/Ca12Al14O33 was difficult to completely restore, incorporation of sulfur in the structure only partly regain by O2. The kinetic model proposes, as generally accepted, a first-order reaction for toluene with activation energy of 82.06kJmol−1 was coincident with the literature data. The Ni/Ca12Al14O33 catalyst was effective and relative cheap, which may be lead to reduction in the cost of hot gas cleaning process.