Kinetic modeling and simulation of high-temperature by-product formation from urea decomposition

The Selective catalytic reduction (SCR) technique is widely applied in exhaust gas after-treatment of diesel engines. Depending on operating conditions, injected urea-water solution (UWS) can form liquid films mixer blades and the pipe wall. Evaporation subsequent reactions wall film lead to deposits urea by-products, respectively. Especially that are not decomposed up high temperatures challenging for SCR technique. Thermogravimetric experiments conducted these stable such as ammelide, ammeline their cyanamide or melamine. An analysis evolving gases during thermal decomposition led a more detailed understanding kinetics. postulated mechanism able predict thermogravimetric analyses results effects variation experimental conditions initial sample mass heating rates. evaluated kinetics, together with recently developed kinetics urea/biuret/triuret/cyanuric acid system Tischer et al. (2019), now be integrated into CFD simulations systems numerically simulate all relevant physical chemical processes UWS equipped aftertreatment wide range conditions.