In 2016 and 2017, AO Machine Building Factory of Podolsk jointly with OOO ZiO-COTES realised the projects for the retrofit of boilers PK-38 Nos.3A, 4B at the Nazarovo GRES power plant. A range of implemented technical solutions [1] allowed reach stable continuous operation of boiler PK-38 at the Nazarovo GRES at loads as high as 270 t/h and significantly reduced nitrogen oxide emissions. Development of the burners system and combustion modes, as well as estimation of nitrogen oxides emissions has been performed using three-dimensional computational fluid dynamics modelling.