Co-combustion of torrefied biomass-plastic waste blends with coal through TGA: Influence of synergistic behaviour

This study investigated the influence of torrefaction (300 °C) on the combustion performances of blends of biomass-plastic wastes (Mango branches (MBr), newspaper (Np), LDPE) using thermogravimetric analysis. The torrefied waste blends were co-combusted with coal at a blending ratio of 25 and 50 wt. % to identify possible interactions between the fuels’ components. Synergistic behaviours were noted during combustion of the torrefied MBr-Np blend and the comprehensive combustion index, Dc was 29 % higher than the predicted value. Interestingly, synergistic interactions were perceived during co-combustion of the different wastes with coal. The measured burnout temperatures (TBO) of all torrefied waste-coal blends were lowered by 6–15 %, compared to their predicted values, especially for MBr-Np-coal blends. Synergistic interactions during torrefaction of MBr-Np not only improved the combustion reactivity of the resulting char but also enhanced coal combustion in the blend compared to combustion of torrefied biomass-LDPE-coal blends. It was concluded that synergies during co-combustion of waste char with coal were governed by the waste type, its composition and the interactions that prevailed during torrefaction of the wastes. •Interactions during torrefaction of MBr-Np enhanced its combustion performance.•Synergies were perceived during combustion of coal with all torrefied waste blends.•Coal burned at lower temperatures when it was co-combusted with torrefied wastes.•Torrefied MBr-Np enhanced coal combustion due to synergies caused by torrefaction.•Waste torrefaction and composition influenced synergies during combustion with coal.