Production of Diesel-Grade Fuel from Co-pyrolysis of Sawdust and Waste Plastics

The increasing generation of sawdust and waste plastics presents significant environmental and waste-management challenges, while the demand for alternative liquid fuels continues to grow. This study investigated the production of diesel-grade fuel through the controlled co-pyrolysis of sawdust and waste plastics in a laboratory-scale fixed-bed stainless-steel reactor. Uda softwood sawdust, Ububra-red hardwood sawdust and C-Way waste plastic bottles were selected as feedstocks based on their carbon contents and energy potential. The feedstocks were blended at varying mass proportions and co-pyrolysed under an inert nitrogen atmosphere at temperatures of 400, 600 and 800 °C. Vapours generated during thermal decomposition were passed through a condenser, and the condensable fraction was recovered as liquid fuel. Feedstock analysis showed carbon contents of 54.68% for softwood, 57.12% for hardwood and 78.19% for the waste plastic, confirming their suitability for thermochemical conversion. The experimental results demonstrated successful conversion of the blended sawdust and waste plastics into hydrocarbon liquid fuel over the investigated operating conditions. The highest liquid-fuel yield of 72 wt.% was obtained at 800 °C using equal quantities of softwood, hardwood and waste plastic (100 g each; 1:1:1 mass ratio). The process also generated char and non-condensable volatile products as secondary fractions. These findings demonstrate the technical feasibility of converting sawdust and waste plastics into diesel-grade liquid fuel through co-pyrolysis, providing a potential waste-to-energy pathway for the recovery of useful fuel from locally available solid wastes. (Co-pyrolysis; Sawdust; Waste plastics; Diesel-grade fuel; Waste-to-energy.)