NOx reduction mechanism in coal combustion with recycled CO2

Coal combustion with CO2/O2 is one of several promising new technologies associated with mitigating the CO2 rise in the atmosphere. In coal combustion with recycled CO2, the amount of NOx exhausted from the system is reduced to less than one third of that with combustion in air. This result is associated with decreased conversion of fuel-N to NOx and reduction of recycled NOx in the flame zone. The effects of CO2 concentration, reduction of recycled NOx, and interaction between fuel-N and recycled NOx on the decrease of the final NOx exhausted from the coal-combustion system with recycled CO2 have been separated for appropriate NOx-reduction mechanisms.