Kinetic modeling of urea decomposition and byproduct formation

A kinetic model for urea decomposition and byproduct formation was developed and validated against thermogravimetric analyses (TGA) of urea and urea-derived byproducts, including biuret and cyanuric acid, at heating rates up to 500 oC/min. The model provided a good description of urea decomposition at all investigated heating rates.

The results indicate that an increase in heating rate causes a shift in production of cyanuric acid into ammelide and limits the overall byproduct formation. Additionally, it is shown that a long reaction time is necessary to fully decompose urea at temperatures corresponding to SCR applications.