Partial oxidation of methane over a ruthenium phthalocyanine catalyst

The partial oxidation of He-diluted CH4 with O2 has been studied in a laboratory flow reactor packed with fragmented pellets of zeolite-encaged Ru phthalocyanine catalyst. Gas compositions (CH4, O2, CO, CO2, and H2) were determined by on-line GC/TCD. Absolute system pressure was maintained at 445 kPa. Most experiments were performed at a constant gas space velocity=0.717/s. Data were obtained over wide ranges of temperature (523-648 K) and CH4/O2 feed molar ratio (0.5-6.5). Observed conversion of CH4 increased with temperature. Product selectivities of H2 and CO increased, while that of CO2 decreased, with increasing temperature and feed CH4/O2. Based on data analysis with an integral plug flow packed bed reactor model, the power law kinetic rate for CH4 conversion was observed to be first order in each of O2 and CH4. A non-linear Arrhenius plot of the global rate constants, together with a Mears correlation analysis, suggests that an external mass transfer resistance becomes active above 573 K in this system.