Combustion simulations of aqueous urea ammonium nitrate monofuel at high pressures

This paper describes a high pressure combustion mechanism of aqueous urea ammonium nitrate (UAN) monofuel. Simulation results were validated by comparison to experiments at pressures of 1–25 MPa and residence times of up to 450 s using a PFR model. Results showed agreement for nitrogen-based species above 15 MPa. For carbon-based species close agreement between experiments and simulations was observed at all pressures. In several conditions, experimental trends were successfully reproduced in the simulation results. Increased pressure and residence time were both found to have a positive effect on pollutant reduction. However, the pressure effect was found to be dominant. A sensitivity analysis was used to identify potential pressure dependent rate limiting reactions during combustion. Different reaction pathways were prominent at 5 and 25 MPa in agreement with the experimental trends. This paper supports the importance of carrying UAN combustion at high pressure to minimize pollutants emission, thereby achieving an environmentally friendly process.