Steam reforming of naphthalene on Ni-Cr/Al2O3 catalysts doped with MgO, TiO2, and La2O3

摘要

Magnesium, lanthanum, and titanium oxide-doped nickel-chromium/alumina catalysts were prepared and their performances assessed in the steam reforming of naphthalene (T: 1,023 K; water-to-naphthalene molar ratio: 16, atmospheric pressure, residence time of 0.55 s; and GHSV = 10,080 h(-1)). Impregnation of nickel and chromium in MgO- and La2O3-doped alumina gave the most active, stable catalysts. Nickel was active in aromatic ring opening, while chromium inhibited the encapsulation of the nickel crystallites by inactive carbon filaments. The use of MgO had a significant effect on the robustness of catalyst due to the formation of MgAl2O4 spinel phase. La2O3 was necessary to drive the reaction toward total gasification. The addition of TiO2 gave poor activity and a soft catalyst Some of the catalyst preparations were characterized before and after reaction by XRD, SEM, DTA, and surface measurements. The physical and catalytic properties are discussed in light of these characterizations. The catalyst optimized during this study showed high crystallite dispersion, excellent crushing strength, and good thermal stability. When comparing the data obtained using Ni/Al2O3 with Ni-Cr/Al2O3 . MgO . La2O3, it is clear that the improved catalyst reached higher conversion and gas yield performances. [References: 43]