FUEL 89 |
| Sulfur poisoning and coke formation during reforming of logistic fuels (diesel, jet fuel, and gasoline) to produce hydrogen for fuel cell systems are two major factors leading to catalyst deactivation. Therefore, development of more stable catalyst formulations is essential. We have evaluated a number of catalyst formulations that combine high reforming activity with the ability to react with the sulfur to produce a stable solid catalyst. In our present study, we prepared catalyst through wet impregnation of commercially available catalyst supports and tested those catalysts with 25-100 ppm sulfur content of the fuel. Thiophene doped n-hexadecane was used as surrogate fuel for diesel. Steam reforming reaction was carried out at 800°C at steam to carbon ratio of 5. We regenerated the deactivated catalyst with air. Three sequential reaction and regeneration cycles were carried out to evaluate catalytic activity and stability. Several catalysts were stable for greater than 100 hr during reforming with 25 ppm sulfur. At 100 ppm sulfur loading, the catalysts showed substantial deactivation within 24 hr, but could be regenerated through combustion with air. These regenerated catalysts then provided high activity and good stability when used in the presence of 25 ppm sulfur. The addition of selected catalyst promoters enhanced the performance of the catalytic system. Surface analysis of fresh and used catalyst provide details regarding the structural changes of the surface, providing critical information into understanding the role of the promoters in enhancing the sulfur tolerance of the catalyst |
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Advances in Hydrogen Production
1:30 PM-5:05 PM, Monday, 11 September 2006 Palace -- Marina Room, Oral
Division of Fuel Chemistry |