A Novel Lab‐Scale Fixed‐Bed Pyrolysis Reactor for Biofuel Production from Agro‐Waste: Experimental Set‐up and Preliminary Life Cycle Assessment Study

Abstract

The present study reports the features and set-up of a novel lab-scale fixed bed pyrolysis reactor for the production of solid and liquid bio-fuels from waste biomass. The fixed bed reactor is tested by carrying out pyrolysis experiments using two different waste biomasses. Olive tree trimmings (OT) and olive pulp (OP), olive cultivation and olive mill industries residues respectively, are pyrolyzed, under nitrogen atmosphere, between 200 and 650 °C for a residence time of 0.5 h. The OT and OP pyrolysis chars were characterized in terms of mass yields, high calorific values (HHVs), proximate and elemental analysis. Char mass yields, on a dry basis (d.b.), decreased from 91 to 23 wt% and from 93 to 32 wt% for OT and OP respectively with increasing pyrolysis temperature. HHVs increased between 200 and 325 °C up to 27.71 and 31.42 MJ/kg for OT and OP respectively but start decreasing when further rising the pyrolysis temperature to 24.36 and 28.44 MJ/kg for OT and OP respectively at 650 °C. The novel pyrolysis system set-up shows to be an efficient and effective tool to test biomass pyrolysis at lab scale level and adapt to produce high energy dense bio-chars for solid fuel applications starting from waste biomass. A preliminary life cycle assessment (LCA) of the pyrolysis process is carried out for the two examined waste biomasses, for calculating the life-cycle environmental impacts for the production of 1 MJ of thermal energy by pyro-char combustion.