Catalysis Enhanced Pyrolysis of Blended Biomass: Effects of Blends Compositions and Catalyst Concentrations
摘要
The oleic industry is one of the most polluting anthropogenic activities in the Mediterranean basin generating huge amounts of solid biomass residues. This study investigates the impact of pine sawdust addition and potassium catalyst concentrations on the pyrolysis behavior of olive mill solid wastes composed of olive pomace and seeds. Four types of lignocellulosic biomasses were prepared from exhausted olive mill solid residues (G) and pine sawdust (S) in different proportions: 100% G (100G), 60%S + 40%G (60 S.40G), 50%S + 50%G (50 S.50G) and 80%S + 20%G (80 S.20G)). Three concentrations of K2CO3 were considered during impregnation phase: 0.1 M, 0.5 M and 1.5 M respectively. A significant catalytic influence of potassium was observed up to 0.1 M for samples with a high percentage of pine sawdust (60 S.40G and 80 S.20G). However, for the other samples (100G and 50 S.50G) the catalytic effect of potassium was observed up to 0.5 M. Moreover, the char yield was considerably enhanced by potassium impregnation, which doubles for the blended biomasses (rising from approximately 21% to 45%) at the highest concentration of 1.5 M. To better interpret these observations, the surface properties of the char were examined using Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (SEM-EDX) and Fourier Transform InfraRed spectroscopy (FTIR). SEM analysis showed that the char generated from pure olive mill residues (100G) exhibited severe surface melting and structural sintering at a highly potassium impregnation concentration (1.5 M). Indeed, beyond a certain threshold of potassium concentration (0.5 M), agglomerations occurred blocking the active sites of the chars.