Detailed Chemical Kinetics Mechanism for Condensed Phase Decomposition of Ammonium Perchlorate

The current study aims to improve the understanding of the complex thermal decomposition mechanism of Ammonium Perchlorate (AP-NH4ClO4). The absence of detailed reaction mechanisms for AP with accurate rate kinetics data in the condensed phase is the main challenge of thermal decomposition and combustion modelling. In the present study, AP-condensed phase elementary reactions were investigated using Ab-initio molecular modelling, in which the polarizable continuum model using integral equation formalism variant (IEFPCM) was used to account for the condensed phase and transition state theory calculations are used for calculating kinetic parameters of the reactions. Gas-phase species evolution profiles were obtained from fast pyrolysis experiments conducted isothermally at three temperatures (420, 440, and 460 °C) at 10 bar gauge pressure. The same are used to validate the reaction mechanism. To simulate the fast pyrolysis experiments, computational model based on mass and species conservation in the condensed phase and gas phase control volumes was developed. The predicted gas phase mole fraction profiles of the decomposition products agree well with the experimental results, indicating that the proposed reaction mechanism captures the liquid phase decomposition of AP.