Synergistic co-gasification of crude glycerol and solid wastes: Thermodynamic efficiency and syngas suitability for clean fuel synthesis

The co-gasification of crude glycerol (CG) with waste tyres (WT), polyethylene (PE) or pinewood waste (PW) in the presence of O 2 and O 2 /H 2 O was explored through an Aspen Plus simulation combined with energy and exergy analysis. Optimal syngas yield and maximum energy and exergetic efficiencies were observed within an equivalence ratio (ER) range of 0.25–0.3 for all three waste materials gasified with crude glycerol. At higher ER values, the energy and exergetic efficiency declined due to a decrease in syngas yield. Steam addition at the optimal ER slightly reduced the cold gas efficiency (CGE) and exergetic efficiency but significantly decreased the overall gasification efficiency (OGE). The hydrogen efficiency (HE) and hydrogen exergetic efficiency showed significant improvements when compared to pure oxygen process-gasification. The co-gasification of crude glycerol and solid waste materials exhibited a positive degree of synergy within the optimal ER range. Co-feeding crude glycerol and waste tyre showed a synergy gain up to 18.46 % based on energy and exergetic efficiency at an ER of 0.3, while co-gasification of crude glycerol and polyethylene achieved an increase in the degree of synergy up to 14.05 %. Both oxygen and oxy-steam co-gasification processes produced syngas compositions suitable for direct fuel synthesis, demonstrating the potential of waste-derived feedstocks in sustainable energy applications. • Co-gasification of glycerol with waste tyres improved gasification efficiencies. • Energy and exergy analysis showed synergy gains up to 18.46 % at ER 0.3 • Polyethylene blends also enhanced process efficiency and fuel flexibility. • Oxy-steam process tailored H 2 :CO ratios for direct fuel synthesis applications.