Pyrolysis is an important process in energy recovery from biomass and also as a previous stage to other processes such as gasification. Valuable gases, such as H2 and CO, can also be generated by pyrolysis. These gases can be useful, among other applications, in chemical synthesis and high efficiency combustion systems such as fuel cells.

The hydrogen-rich product gas from biomass pyrolysis is believed to become a valuable energy source with natural carbon dioxide. However, biomass has low energy density, so the enhancement of the product gas quality from biomass gasification is necessary. Beside a particular problem which has not been completely solved so far is tar formation. Catalytic processes are considered as the most promising method with the highest potential to contribute a solution to this problem. Temperature is an important variable in thermal decomposition processes of biomass, significantly influencing the product distribution. Pyrolysis is an endothermic process, and the use of low temperatures in this process decreases the input energy for a system that is very positive from an energetic point of view and the system operation is easier than high temperature systems.

For both catalytic activity and economic reason, a nickel catalyst is the most suitable choice and the most widely used in the industry among metals like Co, Pt, Ru and Rh, which were investigated by many authors [10,17-23]. Moreover, nickel based catalysts are reported to be quite effective not only for tar reduction, but also for decreasing the amount of nitrogenous compounds such as ammonia [24]. In most reports, conventional nickel catalysts, which had been developed for steam tar reforming, were tested [6,9,13,15,25,26]. However, the investigations are still limited because of coking [19,22] or the use of expensive materials as catalyst supports (CeO2, AhO3, Al, SiO2, TiO2, ZrO2, MgO or WO3). Among the above investigations, the most interesting one concerning the current study is brown coal gasification by the addition of a nickel catalyst in fluidized bed gasification at low temperature [21-23]. However, nickel catalyst has only been used for coal gasification itself.

To satisfy both high quality of product gas and use of a cheaper catalyst support (brown coal char), in this study, nickel loaded brown coal char catalyst has been developed for the new purpose of decomposing tarry material from woody biomass pyrolysis. A suitable temperature for catalytic tar decomposition was investigated in a two-stage fixed bed reactor. The effect of temperature on gas yield and carbon conversion have been discussed in detail and compared in the case of non catalyst and Ni/BCC catalyst. The better temperature is a reference result, being used in fluidized bed gasification which is available for continuous tests to assess durability. Catalytic activity was tested, evaluated by woody biomass pyrolysis in a fluidized bed gasifier for both of Ni/BCC and reference catalyst

Ni/АЬОз. In a lab scale fluidized bed gasifier (FBG) Experiments, inside of FBG reactor is constructed by two beds, the primary one is a fluidized bed with sand where biomass was fed to produce tar, and the other is a catalyst bed that is used to evaluate and to compare catalytic activity between the new catalyst and a conventional Ni/AhO3 catalyst. The Ni/BCC catalyst is prepared by ion exchange method, dried at 380 K in nitrogen for 24 h, and is then calcined at 923 K in nitrogen for 90 min. Sample for characterization of catalyst was prepared on the fixed-bed reactor under various conditions such as nickel loaded brown coal particle size range of 0.5 to 2 mm, pyrolysis temperature range of 823 to 1023 K that are needed to investigate the effect both of catalyst particle size and pyrolysis temperature on crystallite size of Ni/BCC. The temperature as a function of gas yield and stable activity of catalyst absence of steam are investigated in this chapter.