Pyrolysis characteristics and response surface optimization analysis of slurry-prepared fly ash and waste composite solid propellant fuel

Waste composite solid propellants possess high calorific value but are challenging to stabilize as slurries. Incorporating fine fly ash optimizes particle size distribution, improves dispersion stability, and balances cost with fuel performance. In this study, dried slurry fuels prepared from crushed propellant and fly ash were analyzed for pyrolysis behavior using thermogravimetric analysis (TGA) coupled with kinetic modeling. The effects of fly ash ratio, oxygen concentration, and heating rate were examined via single-factor tests and response surface methodology (RSM). Results indicate that fly ash content is the primary factor governing residue quality (p < .0001), with higher proportions enhancing thermal stability and suppressing rapid decomposition. Elevated oxygen concentration and heating rate increased reactivity and reduced residue. Kinetic analysis revealed that activation energy rose with fly ash content, while the 50% fly ash blend exhibited the lowest value (226.42 kJ/mol) and the highest reactivity. This research provides a theoretical basis and data support for the green disposal of propellant waste and the engineering application of mixed fuels.