Effect of Pd and Ce promoters in the activity of Ni/ γ-Al2O3 catalysts for the dry reforming of methane

Abstract

Synthesis gas is an important feed stock for the chemical and petrochemical industries to produce many kinds of chemical such as methanol, ammonia. It is also a source for hydrogen that can be used directly or in a fuel cell. An experimental investigation was carried out using Ni supported catalysts on γ-Al2O3 prepared by impregnation method. The catalysts were dried at 120C and calcined at 900C. The reforming reactions were carried out using CO2/CH4/N2 feed ratio of 5/5/1, F/W=44 ml/min.gcat and reaction temperatures of 500-800˚C. Influences of Pd, and Ce promoters, catalyst stability, coke deposition and (H2/CO) ratio were studied. The prepared catalysts were tested in AMI-2000 ZETON ALTIMARA micro reactor at atmospheric pressure. The effluents were analyzed using an online gas chromatography equipped with a thermal conductivity detector. Spent and fresh catalysts were characterized by using SEM and TGA techniques. The best performance was found using (3 wt % Ni + 0.15 wt % Ce / γ-Al2O3) catalyst. It also provided the least coke formation at high temperatures (700-800˚C). The highest activities measured, in terms of CH4 and CO2 conversions were 90.5% and 92.6% at 800C respectively. Stability test was carried out for 9 h.