Reforming of natural gas using coking-resistant catalyst for fuel cell system applications

• Published in: Journal of power sources 2013-01, Vol.222, p.253-260
• Main Authors: Hsu, Ning-Yih, Jeng, King-Tsai
• Format: Article
• Language: English
• Subjects: Applied sciences; Autothermal reforming; Catalysis; Catalyst support; Catalysts: preparations and properties; Chemistry; Coking-resistance; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; General and physical chemistry; Natural gas reforming; Reforming catalyst; Solid oxide fuel cell; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.08.086

A coking-resistant catalyst prepared using a novel catalyst support is characterized and its performance on reforming of natural gas for fuel cell system applications is investigated. Two key issues, i.e., the stability of catalyst under the reforming environment and deposition of carbon on the catalyst surfaces leading to deactivation, have to be resolved. The reforming operations are performed using a modified external autothermal reforming (ATR) approach. Desulfurized natural gas is used as a feedstock to avoid catalyst poisoning and air is exploited as an oxidant. It is found that the reforming catalyst is able to remain stable and free from pulverization at the desired operating conditions when α-Al2O3 is employed as a catalyst support in place of the commonly used γ-Al2O3 counterpart. In addition, the ceria (CeO2)-assisted Pt catalyst coated on the α-Al2O3 support, i.e., Pt/CeO2/α-Al2O3, is able to significantly eliminate the coking problem with a CH4 conversion rate >99% and a generated H2 concentration ∼62% at 1073K. A reaction mechanism is proposed to elucidate the coking-resistance of the catalyst, which also accounts for the stability of the catalyst. The reforming catalyst has been tested continuously for 2400h and is still able to maintain a good operating condition. ► α-Al2O3 is a more stable catalyst support than γ-Al2O3. ► The Pt/CeO2/α-Al2O3 catalyst is able to effectively eliminate coking problem. ► The CeO2 coating layer provides excellent coking resistance for the catalyst. ► The CeO2 coating layer also prevents catalyst from being pulverized.