Characterizing biomass pellets produced from torrefied biowaste and waste medical plastic pyrolysis oil

The saw-milling residues are biowaste generated during the sawing of logs into lumber, and they may be lucrative when turned into biowaste pellets. Using biowaste as a renewable fuel helps address the limited availability of fossil fuels, reduces pollution, and additionally decreases the need for landfill. This study investigated the thermal reaction kinetics and physical properties of oxidative torrefied sawdust (TSD) and waste medical plastic pyrolysis oil (WMPPO) blended pellets, TSD25 and TSD50, referring to 25% and 50% of WMPPO with TSD, respectively, using thermogravimetric analysis (TGA), whereas the pellets are prepared using a small-scale pellet processing system. The reported additional physicochemical properties like density, pellet durability index (PDI), moisture adsorption, and impact resistance (IR) were as per the American Society of Agricultural and Biological Engineers (ASABE) recommended tests for densified fuel pellets, proximate Fourier transform infrared spectroscopy (FTIR) were used for identifying the blend’s chemical composition active constituents. Ultimate analysis was carried out for the elemental analysis, and the morphological study was conducted using scanning electron microscopy. The samples have a moisture content of less than 10%, a volatile matter content that seems to be 75 to 82%, and an ash content that seems to be 1.05 to 6.65%. Oxidative torrefied sawdust scanning electron micrographs reveal micro, macro, and meso pores and improved the Brunauer-Emmett-Teller (BET) surface area. FTIR and TGA validate the addition of 50% WMPPO with TSD-controlled combustion zone temperature with the activation energy of 27.63 kJ/mol for an effective thermal conversion process. The physicochemical properties of density, pellet durability index (PDI), moisture adsorption, and impact resistance (IR) for sawdust (SD), TSD, and TSD blends with WMPPO are also reported. Both low-temperature torrefaction and waste medical plastic pyrolysis oil blending reduce volatile loss and improve fuel pellet physicochemical and thermochemical characteristics.