The motivation for this work is the development of a live optimization tool to control the additive input of the selective non-catalytic reduction (SNCR) process. An essential component of the model is the description of the additive input by technical spray nozzles. This approach aims to provide sufficiently accurate results through targeted simplifications with short computation times. Established CFD calculation methods do not meet this requirement.

Based on an already developed semi-analytical approach to calculate the mass transfer of technical sprays into a reaction environment [1], this paper demonstrates the feasibility of a future potential implementation via comparison with a CFD study. In preparation for a practical application, the evolution of the existing model to consider urea injection and decomposition under typical SNCR conditions is also presented. Initially, the drying and formation of a solid urea crust is considered. Followed by complete particle drying, the release occurs due to the thermal decomposition of the urea. Part of the assumptions made based on experimental studies of single droplet evaporation of urea-water solutions (UWS) in an ultrasonic levitator.

The model was also extended to include the reaction kinetics of the subsequent nitrogen oxide (NO) reduction reactions. initial results of a model validation with operating data from a biomass CHP plant are available.