Synergistic transformation: Kinetic and thermodynamic evaluation of co-pyrolysis for low-rank bituminous coal and polyurethane foam waste

Abstract

Co-pyrolysis is regarded as a sustainable and ecologically friendly method of improving waste management, pollution control, and renewable energy security. This investigation reports a thermo-kinetic study of low-rank coal-polyurethane foam waste (C-PU) blends through co-pyrolysis and was characterized using a number of techniques such as CHNS-O, GCV, and FTIR. The thermal degradation behavior of C-PU blends during co-pyrolysis via TGA is studied, whereas the degradation process happens in three stages i.e. moisture, devolatilization, and slow degradation of the char in the temperature ranges viz. (25 –140 °C), (140 – 580 °C), and (580 – 900 °C) respectively. Synergistic effects observed may improve product qualities compared to those from separate pyrolysis. The presence of synergistic effects during co-pyrolysis was demonstrated by the positive variation in WL% and DTGmax values. The Coats-Redfern integral method was utilized to investigate the thermo-kinetic parameters of C-PU blends through twelve (12) reaction mechanism models. The activation energy (Ea) for 100C and 100PU was 60.08 kJ/mol and 100.8 kJ/mol via F2 and F3 models, although the optimum blend (50 C-50PU) showed 67.01 kJ/mol and 26.74 kJ/mol via F2 and D3 model in the first and second stage. Thermodynamic characteristics i.e. (∆G) and (∆H) displayed positive values, while (∆S) for each C–PU blend was negative, but the best blend further lowered it. It was found that the fuels could be ranked in the following order 100PU> 50 C-50PU> 100 C based on mean reactivity and pyrolysis factor. The co-pyrolysis of polyurethane foam waste with low-rank coal to develop alternative energy sources has been proposed as a potential method and is critical for designing an effective large-scale reactor system thus understanding the solid-state co-pyrolytic kinetics.