Caractérisation de grignons d’olives en vue d’une valorisation thermochimique par gazéification

Biomass is a renewable energy source that can make a significant contribution to reducing fossil fuels consumption. The use of agricultural or agro-industrial waste such as olive mill solid residues is particularly relevant. Gasification is a promising waste-to-energy technique for this type of lignocellulosic residues. The technology however is adapted to a relatively limited panel of solid waste fuels of defined specifications, which must therefore be characterized properly. The purpose of this study was to analyze and compare olive mill solid residues from 3 different origins by complementary techniques such as Fourier transform infrared spectroscopy, thermogravimetry coupled to differential scanning calorimetry and analytical pyrolysis combined with gas chromatography/mass spectrometry (Py-CG/SM). The results underlined the complex nature of the residues, which are mainly organic. In addition to the major compounds (cellulose, hemicelluloses and lignin), the presence of several minor organic constituents was shown. Py-CG/SM showed that the gas produced by pyrolysis contains several degradation products of lignocellulosic material and olive oil. The influence of the olive oil extraction process (two-phase or three-phase) was also highlighted. The thermochemical degradation of olive mill residues follows a complex pathway but the composition of the residues meets most of the requirements parameters for gasification.