Using CFD for NO$_x$ emission simulation in a dual fuel boiler

The present work is aimed at reducing NO$_x$ formation in a 250 MW dual fuel boiler by means of air staging and over-fire air. CFD simulations are performed to identify the best locations in the boiler walls to install air and fuel injectors. By installing injectors at these locations, it is possible to reduce NO$_x$ production by more than 70% without increasing the amount of CO. This value is in good agreement with available data reported in the literature. Simulation results (gas species analysis and temperature) have been validated with real data taken at the full-scale boiler.