Combustion of Dry Sewage Sludge Particle in a Fluidized Bed Reactor

 This paper presents a mathematical model of the cylindrical particle combustion in a fluidized bed reactor. This particle is composed of sewage sludge. The model performs a mathematical description of the physical and chemical phenomena that occur during particle combustion. The uniform particle model without ash accumulation is proposed. Sewage sludge is considered composed of three fractions. Two fractions pyrolyzed forming char. Then, this char is burned. The other fraction is burned without pyrolysis. In order to describe the mechanism and kinetics reaction, data from thermogravimetric analysis were used. The reaction kinetics was proposed as a function of mass loss of each fraction. To validate the model, the particle combustion time obtained by the simulation was compared with the experimental combustion time. Also, this work presents the combustion atmosphere temperature and the particle size influence in the combustion phenomena. The model predicts acceptably the combustion time, according to experimental results. Keywords sewage sludge particle – combustion – fluidized bed reactor – mathematical model