Isothermal differential characteristics of gas–solid reaction in micro-fluidized bed reactor

• Published in: Fuel (Guildford) Vol. 103; pp. 29 - 36
• Main Authors: Yu, Jian, Zeng, Xi, Zhang, Juwei, Zhong, Mei, Zhang, Guangyi, Wang, Yin, Xu, Guangwen
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.2013; Elsevier
• Subjects: activation energy; Applied sciences; combustion; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; Gas–solid reaction; graphene; Graphite combustion; growth models; heat; Isothermal differential characteristics; Micro-fluidized bed; Reaction kinetics; temperature; Isothermal differential characteristics; Gas–solid reaction; Graphite combustion; Micro-fluidized bed; Reaction kinetics; Fluidized bed reactor; Gas solid reaction; Temperature effect; Combustion; Reaction rate; Kinetic model; Heating; Gas-solid reaction; Graphite; Kinetics; Inhibition; Measurement method; Activation energy
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2011.09.060

The isothermal differential characteristics of the gas–solid reaction occurring in a micro-fluidized bed reactor were studied using the indigenously developed Micro-Fluidized Bed Reaction Analyzer (MFBRA). The combustion of graphite powder in micrometers was taken as the model reaction because of its negligible internal diffusion and chemical-reaction simplicity. With minimized inhibitions from both the internal and external diffusions, the reaction in MFBRA at a preset temperature was analyzed by using the isothermal kinetic approach, resulting in an activation energy of 165kJ/mol and a pre-exponential factor of 1061/s. The reaction was further found to be subject to the nucleation and growth model expressed by G(α)=−ln(1−α). Measuring this reaction in TG via the programmed heating method resulted in the similar activation energy and the same reaction function model (by extrapolating to zero conversion). Comparing with the non-isothermal approach for TG that involves complicated mathematical calculations, the isothermal differential approach for MFBRA allowed the separation of the temperature effect (i.e., the reaction rate constant) and kinetic function model, thus providing a simple and reliable determination of the gas–solid reaction kinetics.