REACTION OF CHAR NITROGEN DURING FLUIDIZED-BED COAL COMBUSTION - INFLUENCE OF NITRIC-OXIDE AND OXYGEN ON NITROUS-OXIDE

The conditions that favor the formation of nitrous oxide from char und er fluidized bed combustion conditions are shown to be the oxidation o f the char to make the nitrogen bound in the heterocyclic rings access ible so that it can react heterogeneously either with oxygen to form N O or with nitric oxide to form N2O. This was demonstrated by measureme nt of the gas composition when a batch of coal particles was introduce d into a fluidized sand bed electrically heated to 1023 K. Oxygen and nitric oxide were added to the fluidizing helium gas in varying concen trations. N2O was formed in amounts that increased with increasing NO concentration showing the importance of NO for N2O formation. The N2O concentration, however, fell to zero when the O2 supply was interrupte d underlying the essential role of oxygen in freeing the organically b ound nitrogen so that it can react with NO to form N2O.