Catalytic performance of Ni catalysts for steam reforming of methane at high space velocity

Abstract

Three Ni-based catalysts, namely Ni/ZrO 2/Al 2O 3, Ni/La–Ca/Al 2O 3 and Ni 0.5Mg 2.5AlO 9 catalysts were prepared, tested and characterized for steam reforming of methane (SRM), especially at high space velocities. Experimental results demonstrated that Ni 0.5Mg 2.5AlO 9 catalysts showed excellent catalytic activity, e.g., the high reaction performance (i.e., activity and stability) at a very short residence time of 20 ms. For the accompanied water gas shift (WGS) reaction with the SRM at the steam to methane ratio of 3:1, the overall hydrogen yield depended on both the CH 4 conversion and the CO 2 selectivity. The results showed that CO 2 selectivity had opposite trend compared with CH 4 conversion in such a short-contact process. Catalyst characterizations by XRD, SEM-EDS, TEM and TGA suggested that the good performance of nickel catalysts was closely related with the good dispersion of the active component. The nano-sized nickel particles in strong interaction with the supports would lead to the good dispersion, thereafter having a slight tendency to sintering, and then to coking.