Effect of Additives on Cracking Characteristics of Dust-Containing Tar over Nickel-Based Catalysts

摘要

To develop tar-cracking catalysts with an industrial application value and to study the effect of dust species on the cracking characteristics of dust-containing tar, four kinds of modified nickel (NO-based catalysts were prepared by the incipient wetness impregnation method. Alkali and alkaline earth metal oxides K2O and MgO and transition metal oxides CeO2 and ZrO2 were used as additives. The activities and stability performances of these catalysts were investigated in a fixed-bed apparatus. The additions of K2O and MgO neutralized the acidity of the catalysts and reduced carbon deposition on the catalyst surface, and the additions of CeO2 and ZrO2 improved active ingredient dispersion. X-ray diffraction studies revealed that the (Zr0.85Ce0.15)O-2 solid solution has good stability. The 2% NiO/1% CeO2/2% ZrO2-Al2O3 catalyst shows the highest activity and stability-among the four modified Ni-based catalysts. Depositions of different species of dust on. the catalyst surface have different,influences on the catalyst performance; MgO, CaO, and Fe2O3 increase the catalytic activity, while SiO2 and Al2O3 decrease the catalytic activity.