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Show NOx Reduction System in MWI Plant 1. Introduction AFRC90 Paper #37 M. YAMAGISHI, T. NAKAO NKK CORPORATION WASTE TREATMENT PLANT TECHNICAL SERVICE DEPT. Before developing NOx Reduction System, NOx production mechanism was investigated. At first using actual operation data of the furnace, the formation volume of thermal NOx was calculated by means of Zeldovich mechanism and the result was below several ppm. Therefore, based on the consideration that the majority of NOx generated by the Waste-to-Energy Plant is Fuel-NOx, the fact was confirmed by the following experiments: The standard refuse that has an adjusted Fuel-N content was combusted using air (02=21% and N2=79%) and gases (02=21% and Ar=79%). The average volume of NOx generated by combustion using 02+Ar was lower by approximately 30% compared with the case where only air was used and it was confirmed that approximately 70% of NOx generated was Fuel-NOx. (Refer to Fig. 1-1) From this consequence, the Fuel-N of refuse is considered to be transformed to N2 and NOx in the furnace by the mechanism shown in Fig. 1-2. It can be seen from the figure that the transformation ratio of Fuel-N to NOx is controlled lower when the 02 concentration is lower in the furnace. - 1 - |