USE OF AN EMPIRICAL MODEL TO STUDY DEVOLATILIZATION OF WASTE

RODRIGUEZ R.; PALACIOS C.; HEKTOR K.; UDAQUIOLA S.

Río de Janeiro

Congreso; 2nd Mercosur Congress on Chemical Engineering-4th Mercosur Congress on Process Systems Engineering; 2005

Univerisdad Federal de Río de Janeiro-Instituto militar de Ing.-PLAPIQUI-Universidad Nacional de Litoral

The behavior of wastes during pyrolysis is of interest for several reasons. In solid combustion, thermal decomposition transforms the starting material into two products, a solid (char) and the so called volatiles. By definition, the latter have enough mobility and / or vapor pressure to evolve from the decomposing substrate. The detailed dynamics of the devolatilization determine the release rates, yields, compositions and heating values of volatiles, and thus influence ignition, flame duration, combustion intensity and emissions rates, their composition and toxicity. The devolatilization of wastes was studied by electrically heating a solid sample in nitrogen flow (nominal pressure, 1atm). A flow reactor was developed to analize the influence of heating rate and composition of waste on the initial and final devolatilization temperatures. A weighing mechanism was designed to register the weight loss of the solid and the yield of volatiles was obtained from this measure. An experimental design was developed to determine the influence of these variables on the initial and final devolatilization temperatures, and their possible interaction. Three heating rates and two different waste compositions were used. The experimental results showed that the final devolatilization temperature is a function of heating rate and composition of wastes and there is no interaction between both. The initial devolatilization temperature depends of heating rate. With this data, an empirical model was developed to calculate the initial temperature, it is valid in the range of studied heating rate.