Species and temperature profiles in a differential sphere bed reactor for the catalytic partial oxidation of n-octane
A method is developed by which temperature and species profiles are measured for the catalytic partial oxidation (CPO) of n-octane in a differential manner in a fixed bed of Pt and Rh-coated α-alumina spheres with a minimum resolution of 1 mm (or ∼0.4 g) of catalyst over a wide range of feed stoichiometries. Results indicate that two regions of catalytic activity are present in the bed: a short (∼1 mm) oxidation zone in the front of the bed and a longer reforming zone downstream. The lengths of the reforming and oxidation zones are dependent on the stoichiometry of the reactor feed. O2 is consumed rapidly on both Rh and Pt catalysts; however, full O2 conversion is reached faster on Rh than on Pt. Both steam reforming and dry (CO2) reforming are observed in the bed downstream of the oxidation zone, but steam reforming is more extensive because higher conversions of H2O are observed than CO2 on both Rh and Pt catalysts. The conversion of H2O and CO2 in the reforming zone is always higher on Rh than on Pt, therefore Rh is a better reforming catalyst than Pt. Low molecular weight hydrocarbons like methane and ethylene are more readily reformed than octane. Results also indicate that alumina sphere beds are better supports for syngas production than alumina foam monoliths.
Graphical abstractA method is developed for measuring temperature and species profiles for the catalytic partial oxidation (CPO) of n-octane in a fixed bed of noble metal coated spheres. The results show that there is first a very short oxidation zone in the front of the catalyst where fuel and O2 are consumed and a longer reforming zone downstream.Figure optionsDownload full-size imageDownload as PowerPoint slide
Journal: Applied Catalysis A: General - Volume 332, Issue 2, 20 November 2007, Pages 171–182