Pyrolysis of spent rapeseed meal: A circular economy example for waste valorization

This study describes an original procedure for protein extraction from rapeseed meal, which due to its well-balanced amino acid composition is used in livestock and aquaculture industries. The waste collected after the extraction process was converted through induction pyrolysis using two different set-ups and different reaction conditions. The choice of process parameters address the reaction towards a high formation of bio-oil (30.5%) and gas (30.7%) or the production of large quantities of bio-char (up to 53%). Bio-oils were characterized through GC-MS and H-1 NMR, to evaluate its composition. The bio-oils are rich in nitrogenous aromatic compounds, in particular pyrrole and derivatives of pyrazines. In addition, other high value-added products such as furfuryl alcohol are also present. A TGA analysis was used to determine the thermal stability of the char and FTIR analysis of the solid fraction shows the presence of residual functional groups on the surface. This study reveals that pyrolysis is a valid way for biomass conversion, solving