Kinetic studies of CH4 oxidation over Pt-NiO/δ-Al2O3 in a fluidised bed reactor

The oxidation of CH4 over Pt-NiO/delta-Al2O3 has been studied in a fluidised bed reactor as part of a major project on an autothermal (combined oxidation-steam reforming) system for CH4 conversion. The kinetic data were collected between 773 and 893 K and 101 kPa total pressure using CH4 and O-2 compositions of 10-35% and 8-30%, respectively. Rate-temperature data were also obtained over alumina-supported monometallic catalysts, Pt and NiO. The bimetallic Pt-NiO system has a lower activation energy (80.8 kJ mol(-1)) than either Pt (86.45 kJ mol(-1)) and NiO (103.73 kJ mol(-1)). The superior performance of the bimetallic catalyst was attributed to chemical synergy. The reaction rate over the Pt-NiO catalyst increased monotonically with CH4 partial pressure but was inhibited by O-2 At low partial pressures (<30 kPa), H2O has a detrimental effect on CH4 conversion, whilst above 30 kPa, the rate increased dramatically with water content. (C) 1999 Elsevier Science B.V. All rights reserved.