MATHEMATICAL MODELING OF WASTE DEVOLATILIZATION

RODRIGUEZ R.; ECHEGARAY M.;CASTRO M.; PALACIOS C.; HEKTOR K.; UDAQUIOLA S.

Londres-Inglaterra

Simposio; 4TH INTERNATIONAL SYMPOSIUM ON WASTE TREATMENT TECHNOLOGIES (TERMAL, NOM- TERMAL AND GAS CLEAN - UP); 2003

University of Southhampton

The nature and dynamics of devolatilization has a great influence on volatiles release rates, yields, composition and heating values. Moreover, the combustion characteristics such as ignition, flame duration intensity and emissions composition and flow rates may change according to this. In order to model the behavior of this process, an experimental and theoretical work was carried out using an electrically heated reactor in nitrogen flow. A computer program was developed to register time, temperature, and wastes mass loss during theses experiences. An experimental design was used to organize the experimentation using three values for heating rate and two different compositions of wastes. A mathematical model was developed to predict loss mass of the wastes during devolatilization based on main phenomena controlling the process: transport phenomena and chemical kinetics of the release of volatiles. The model assumes a first order chemical reaction with an Arrhenius rate constant. The particle temperature was determined mathematically from gas temperature. The method of finites differences was used to solve the equations simultaneously. The comparison of experimental data with the model calculations gives a good approximation. The exponential factor and activation energies have values which variation satisfy the values found for this kind of phenomenom. This mathematical model may be incorporated into a general model of incinerator used to burn medical wastes.