Thermogravimetric and kinetic analysis of biomass and polyurethane foam mixtures Co-Pyrolysis

Highlights: • Decomposition of biomass sawdust and polyurethane express similar behaviour. • Introduction of polyurethane decreased activation energy compared to sawdust. • Increment of heating rate shifted decomposition to higher temperatures. • Mixture with equal share of both compounds express the most unstable behaviour. • Mixture with 25% of polyurethane shows potential for further extended research. Alternative fuels are crucial for the decarbonisation of high-energy demanding processes. The utilisation of waste materials to produce alternative fuels is especially interesting since, the co-pyrolysis of waste plastics and biomass was lately introduced as promising method since the synergistic effect might enhance the product properties compared to those from individual pyrolysis. Furthermore, the utilisation of waste biomass, like sawdust, is interesting since it does not influence the sustainability of biomass consumption, and even more, it avoids the usage of raw feedstock. Thermogravimetric analysis is performed to determine the thermal degradation behaviour and kinetic parameters of investigated mixtures to find the most appropriate utilisation method. Co-pyrolysis was conducted for three mixtures with the following biomass/polyurethane ratios: 75-25%, 50-50%, 25–75%, over a temperature range of 30–800 °C, at three heating rates 5, 10 and 20 °C/min, under an inert atmosphere. Obtained results were subjected to comprehensive kinetic analysis to determine effective activation energy using the isoconversional model-free methods and provide a detailed analysis of the samples' thermal degradation process. This work aimed to identify the main thermal decomposition stages during co-pyrolysis of biomass and polyurethane mixtures and provide the mixture composition's influence on the considered thermochemical conversion process.