71MWe PFBC demonstration plant was successfully operated in the period of 1992 to 1997 in EPDC Wakamatsu Work to complete all the tests of phase I. During the operation, emissions of NOx and N2O ware continuously measured under different load condition and different type of coal and their mixture. Such operational conditions influenced operational parameters such as temperatures of combustion and exhaust gas, pressure in the boiler and oxygen content in the exhaust gas, etc. The effect of such operational parameters on emissions of NOx and N
2O was analyzed.
Since the nitrogen in the fuel was found to be the sole source of NOx and N
2O, the emissions of NOx and N2O were normalized by fuel-N to calculate conversion. The effect of operational parameters on conversion of NOx, that to N
2O and overall conversion of N into nitrogen oxides (NOx +2N
2O) were analyzed. This overall conversion as well as the conversion into N2O was well correlated to the temperature of cyclone gas (T
c) and square root of P
O2 in the exhaust gas. The conversion into NOx was calculated as the difference of overall and N
2O conversions. The concentrations of NOx and N
2O are thus estimated by use of functions of Tc and P
O2 named ASH
TR.
Parameters in the functions were experimentally defined using a coal to establish ASH
TR equations. The equations were confirmed to be applied for other coals and their blends and to estimate the rapid change of NOx concentration due to the rapid change of P
O2 and T
c
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