Study On Catalytic Reforming Of Model Tar Using Spinel Type Catalyst Based On Fe-Ni-Al

Biomass gasification can efficiently realize the utilization of inefficient biomass energy, and also can reduce our dependence on fossil energy, protect the ecological environment. However, the gasification process inevitably produces tar by-product which affects equipment operation and energy utilization ratio. The traditional supported metal catalysts for tar removal cannot resist high temperature and become inactivated easily. Thus, the development of an economic and reliable catalysts has became a hot issue.Spinel is a kind of substance with own fcc structure and the spinels are common used in hyperthermal material and catalytic field. In this study, three spinel catalysts Ni Al2O4, Fe Al2O4 and Ni Fe2O4 have been prepared for toluene catalytic cracking. At the same time, the catalysis characteristics of Ni Al2O4 catalyst was compared with a traditional Ni O/Al2O3 catalyst based on the toluene catalytic cracking tests. The main results for this study are as follows:(1) Different preparation methods and calcination temperature have different effects on specific surface area and grain growth. Compared with the impregnation method and gel method, the coprecipitation method forms the largest specific surface area, respectively is 77.89 m2/g(Ni Al2O4),62.35 m2/g(Fe Al2O4),52.60 m2/g(Ni Fe2O4). The results indicated that the higher the calcination temperature, the more beneficial to the unit cell growth of and spinel formation.(2) The catalytic performances of Ni Al2O4, Fe Al2O4 and Ni Fe2O4 on the tar catalytic cracking were tested in on a small catalytic furnace experimental platform. The corresponding results showed that in the same reaction conditions, the catalytic efficiency of these three catalysts followed a order of Ni Fe2O4>Ni Al2O4>Fe Al2O4. According to the experimental results, the catalytic efficiency and hydrogen selectivity on tar catalytic cracking of three catalysts were sensitive to temperature. The catalytic efficiency as well and the hydrogen selectivity increased with the increasing of reaction temperature. At 800?, the highest conversion of toluene is 99.5%(Ni Fe2O4), 85.30%( Ni Al2O4), 28.24%(Fe Al2O4) with a hydrogen selectivity of 92.13%, 92.87%, 69.67%, respectively.(3) Experiments of this research found that the Ni Al2O4 performed better than traditional Ni O/Al2O3 catalyst in catalytic activity at high temperature, hydrogen selectivity and resistance of coke. At 800?, Ni Al2O4 could even remain a 100% catalytic property(85% conversion) after 120 min catalytic reaction. However, tar conversion of the traditional Ni O/Al2O3 reduced up to only 10% after 40 min tests, which is quite lower than the conversion at the beginning 76.32%.