Zirconia and alumina based catalysts for steam reforming of naphthalene

The present paper deals with experimentation of ZrO₂ and Al₂O₃-supported catalysts for conversion of naphthalene, chosen as tar model compound of pyrolysis or gasification syngas. In particular, the reforming capacity of active metals and promoters such as Co, Ni, Fe, Cr, Ce and Pt was tested in a fixed bed reactor at temperature from 400 to 900 °C. As regards ZrO₂-supported catalysts, the best results were achieved by the Ni/Fe/Pt catalyst with 96% naphthalene conversion, 78% and 280% as CO and H2 production yield at 800 °C. Regarding Al2O3-supported catalysts, they were more active on average than the zirconia ones, achieving a very good performance even at 500 °C (90–100% naphthalene conversion, 30–40% CO yield and 300–350% H2 yield at 550 °C). Influence of different amounts of alumina, montmorillonite and carbon on carrier composition as well as pellets’ size were also studied. Both zirconia and alumina catalysts showed deactivation at higher temperatures due to coke deposition, resulting in a strong H₂ production drop. Regeneration of catalysts by O₂ and steam as well as activation by H₂ were also studied. The activated catalyst was able to convert more than 99% naphthalene at 450 °C with a CO and H₂ production yield of 26% and 420%, respectively.