NOx emission from a 71 MWe pressurized fluidized bed combustor

Flue gas NOx concentration was measured at the outlet of gas turbine (the inlet of de-NOx catalyst) of a 71 MWe pressurized fluidized bed combustor. The effect of operating parameters on NOx emission was approximated by assuming a linear combination of three independent parameters, concentration of O2 in the flue gas, SO2 removal efficiency, and dense bed temperature. Sensitivity factors for different type of coals were obtained. The relationship between the sensitivity factors and fuel ratio (fixed carbon/volatile matter ratio) was obtained. NOx emission was well approximated by the present approximation, even for coals/coal mixtures that were not used to determine the sensitivity factors. NOx emissions for coal/coal mixtures and combustor operation under fly ash recycle conditions can be predicted approximately from the equation derived from other coals under conditions without fly ash recycle.