Effects of Selected Promoters on Ni/γ-Al2O3 Catalyst Performance in Methane Dry Reforming

The Ni catalysts supported on gamma-Al2O3 were synthesized by an impregnation method. Their catalytic performance in methane dry reforming was investigated. The reforming reactions were carried out in a microreactor using a CO2:CH4 feed ratio of 1:1, a F/W = 2640 ml/(h.g), reaction temperatures between 500-850 degrees C, and at atmospheric pressure. The influence of Ca, Ce, and Zr promoters on catalyst stability, coke deposition, and the H-2/CO ratio were also studied. Effluents were analyzed using an online gas chromatograph equipped with a thermal conductivity detector. The spent and fresh catalysts were characterized by scanning electron microscopy and thermogravimetric analysis. It was found that 3%Ni/gamma-Al2O3 promoted with 0.15% Ce and 0.05% Ca gave the best performance and resulted in less coke formation. The highest CH4 and CO2 conversion activities were found to be 94.1% and 98.3% at 850 degrees C, respectively. Stability tests were carried out for 130 h and this provided a H-2 yield of 91%. Moreover, the amount of formed carbon was negligible and did not increase to more than 1.5 wt%.