Methane dry reforming using Ni/Al2O3 catalysts: Evaluation of the effects of temperature, space velocity and reaction time

In this study, 15% Ni/Al2O3 and 30% Ni/Al2O3 catalysts were prepared by the wet impregnation method and characterized by flame atomic absorption spectrometry (FAAS) (metal content), N-2 physisorption, temperature programmed reduction (TPR), X-ray diffraction (XRD) and temperature programmed desorption of ammonia (TPD-NH3). A continuous flow tubular reactor was built to perform the catalytic reaction tests, and the following reaction variables were analyzed: reaction temperature (600-700 degrees C range), space velocity (WHSV of 15 and 45 L h(-1) g(cat)-1) and reaction time (up to 10 h). Increasing the reaction temperature in the dry reforming reactions led to higher H-2 yields and higher conversions of CH4 and CO2. In general, better conversion rates were achieved in the reactions performed with the 15% Ni/Al2O3 catalyst. In the reactions in which the space velocity was varied, it was observed that increasing the space velocity (WHSV of 45 L h(-1) g(cat)-1) decreased CH4 conversion so the reaction rate is also controlled by the bed length and hence favored the dry reforming reaction. The results of the reaction tests performed for 10 h indicated that no significant loss of catalytic activity occurred during the reaction, therefore no deactivation occurred by coke deposition or metal sintering. (C) 2016 Elsevier Ltd. All rights reserved.