Syngas Production from CH4 Dry Reforming Over Coeni/Al2O3 Catalyst: Coupled Reaction-Deactivation Kinetic Analysis and the Effect of O2 Co-Feeding on H2:CO Ratio

• Main Authors: Foo, Say Yei, Cheng, C. K., Nguyen, Tuan-Huy, Adesina, Adesoji A.
• Format: Article
• Published: Elsevier 2012
• Subjects: QD Chemistry
• Online Access: http://umpir.ump.edu.my/id/eprint/6788/; http://dx.doi.org/10.1016/j.ijhydene.2012.08.136

The dry and oxidative dry reforming of CH4 over alumina-supported CoeNi catalysts were investigated over 72-h longevity experiments. The deactivation behaviour at low CO2:CH4 ratio (2) suggests that carbon deposition proceeds via a rapid dehydropolymerisation step resulting in the blockage of active sites and loss in CO2 consumption. In particular, at high temperatures of 923 K and 973 K, a ‘breakthrough’ point was observed in which deactivation that was previously slow suddenly accelerated, indicating rapid polymerisation of deposited carbon. Only with feed CO2:CH4 > 2 or with O2 co-feeding was coke-induced deactivation eliminated. In particular, O2 co-feeding gave improved carbon removal, product H2:CO ratios more suitable for downstream GTL processing and stable catalytic performance. Conversion-time data were adequately fitted to the generalised Levenspiel reaction-deactivation model. Activation energy estimate (66e129 kJ mol1) was dependent on the CO2:CH4 ratio but representative of other hydrocarbon reforming reactions on Nibased catalysts.