Selective hydrogen combustion over Pt-Sn/Al₂O₃ catalyst in the presence of n-hexane

The selective hydrogen combustion (SHC) in the presence of n-hexane was studied over Pt-Sn/Al₂O₃ catalyst to investigate the feasibility of directly heat supply for pyrolysis process. With air as the oxygen source and n-hexane as the representative of cracking hydrocarbons feedstock, the selective hydrogen catalytic combustion was compared with hydrogen non-catalytic combustion under various temperatures. The results indict that Pt-Sn/Al₂O₃ is a good catalyst for SHC; the selectivity of Pt-Sn/Al₂O₃ catalyzed hydrogen combustion is remarkably higher than that of non-catalytic hydrogen combustion. There exists a critical temperature for Pt-Sn/Al₂O₃ catalyzed SHC reactions. The selectivity of catalytic SHC keeps at 90% when the feedstock inlet temperature is below 650℃; however, it decreases at elevated inlet temperature. Moreover, the ratio of hydrogen to hydrocarbon and the ratio of hydrogen to oxygen may also significantly influence the selectivity of SHC under certain temperature.