In this investigation, coal and biomass are blended together and cofired through a single injector to maximize the potential for fuel interaction.  NO_x emissions are monitored as a function of exit oxygen concentration in the MFC test section.  Representative results are plotted here.

This is a representative example of NO_x emissions as a function of overall stoichiometry for a coal-biomass blend with a biomass (wood in this case) with a low nitrogen content.  The fuel nitrogen contents in this case were 1.2 and 0.18 lb N/MM Btu for the coal and wood, respectively.

This is a representative example of NO_x emissions as a function of overall stoichiometry for a coal-biomass blend with a biomass (old-growth switchgrass in this case) with a moderate nitrogen content.  The fuel nitrogen contents in this case were 1.0 and 0.77 lb N/MM Btu for the coal and wood, respectively.