Partial oxidation of methane over a ruthenium phthalocyanine catalyst

The partial oxidation of He-diluted CH4 with O-2 has been studied in a laboratory flow reactor packed with fragmented pellets of zeolite-encaged Ru phthalocyanine catalyst. Gas compositions (CH4, O-2, CO, CO2, and H-2) 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/O-2 feed molar ratio (0.5-6.5). Observed conversion of CH4 increased with temperature. Product selectivities of H-2 and CO increased, while that of CO2 decreased, with increasing temperature and feed CH4/O-2. 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 O-2 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. (C) 2014 Elsevier Ltd. All rights reserved.