Partial oxidation of n-hexadecane into synthesis gas over a Pd-based metal monolith catalyst for an auxiliary power unit (APU) system of SOFC

• Published in: Applied catalysis. B, Environmental Environmental, 2011-01, Vol.101 (3-4), p.348-354
• Main Authors: Kim, HakJoo, Yang, JungIl, Jung, Heon
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Catalysis; Catalysts; Catalytic partial oxidation; Chemistry; Crystallites; Diesel fuels; Diesel reformer; Exact sciences and technology; General and physical chemistry; Oxidation; Palladium; Pd catalyst; Redox mechanism; Synthesis gas; Synthesis gas production; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; X-ray photoelectron spectroscopy
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2010.10.003

[Display omitted] ▶ Fast start-up accomplished with a novel fuel injection and vaporization system. ▶ Partial oxidation on Pd catalyst proceeds via two-stage redox mechanism. ▶ Triply promoted Pd catalyst shows enhanced instant re-oxidation ability. ▶ Triply promoted Pd catalyst shows higher synthesis gas productivity. The developed diesel fuel reformer presented in this study consists of three components: a fuel injection part working with an air-blown nozzle; a fuel vaporizing part; catalytic converting part. The injected diesel fuel was vaporized on the surface of the electrically heated cylindrical metallic monolith cell (EHC; electrically heated cell). With our injection and vaporization systems, fast start-ups within 4min were accomplished at low energy consumption in the stand-alone mode; this proved practicable for transportation applications. The palladium-based catalyst was prepared by the dip coating method. All SEM, TEM, and XPS analyses showed that an intensive and uniform catalyst layer was formed on the metallic monolith surface, composed of palladium oxide crystallite impregnated on alumina support. The catalytic partial oxidation of n-hexadecane was carried out by varying the C/O ratio and steam/C ratio within the GHSV in the range of 30,000–100,000h−1. Both TPO and XPS analyses were performed for tracing the reaction mechanism of the partial oxidation of n-hexadecane into synthesis gas under the palladium-based catalyst. Partial oxidation over the palladium catalyst was proposed to proceed via the Mars & van Krevelen two-stage redox mechanism. Addition of CeO2, BaO, and SrO promoters to the Pd/Al2O3 catalyst improved thermal stability, as well as the ability of instant re-oxidation of metallic Pd to PdO during the redox cycles, which gave rise to an increase in catalytic activity for higher synthesis gas productivity of higher H2/CO ratios and lower CO2 selectivity.