Detailed kinetic study of phenol decomposition under isothermal conditions to understand tar catalytic cracking process

• Phenol decomposition kinetics were studied under isothermal condition.
• A micro fluidized bed and a liquid injector were designed.
• The values of activation energy for generating H2 and CO were obtained.
• Catalytic characteristics of dolomite and CaO were further revealed.

Tar decomposition is important and indispensable for application of biomass resource by pyrolysis and gasification. Phenol was used as model biomass tar to study the kinetics of thermal decomposition in a two-stage micro fluidized bed under isothermal conditions using sand, dolomite and CaO as bed material in the upper stage. The Friedman method and universal integral method were applied for the determination of kinetic parameters for forming H2 and CO by phenol decomposition. The results showed that temperature exerted significant influence on the formation of CO and H2 and the time for complete releasing of these two gas components became shorter with the increasing temperature. The complete conversion time decreased significantly using dolomite and CaO as bed material compared with sand. The values of activation energy were smaller for generating H2 compared with CO, indicating that H2 formation was easier compared with CO. In addition, dolomite showed the best catalytic activity on the formation of CO and H2 among these three materials as the corresponding activation energy was the lowest.