Characterization and modeling of pyrolysis of the two-phase olive mill solid waste

In this work, first, the two-phase olive mill solid waste was characterized in terms of its physical–chemical properties, which can be useful for its use in pyrolysis units. Then, its behavior on pyrolysis processes was studied by dynamic thermogravimetry and derivate thermogravimetry. For the simulation of pyrolysis processes a kinetic model including three independent parallel reactions was used. The characterization results showed that the solid presents a size distribution with about 66% of particles > 1.00 mm, while the percentage of fines (< 0.250 mm) is only of 1.50%. The moisture content is very high (around 70%), being one of the main characteristics of the solid that makes its direct use as a fuel difficult. However, the low sulfur value (< 0.1%) is very suitable from the environmental point of view, reducing SO2 emissions. The results of the proximate analysis are within the range of most biomass waste and the gross calorific value obtained was 4897 kcal/kg. The thermal decomposition in an inert atmosphere can be modeled by separate decomposition of each of the three fractions which constitute the material. The results of both, physical–chemical characterization and thermogravimetric study show that the two-phase olive mill solid waste could be treated in energy recovery installations.