The CRF has been
involved with a series of laboratory experiments that have examined the influence of
cofiring on ash deposition, NOx production, and fly ash properties using ash
deposition and NOx concentration data collected during cofiring
tests of blends of five different fuels. The results demonstrate that rates of ash
deposition and NOx concentration produced by cofiring biomass
and coal do not vary linearly with fuel blend. The measurements demonstrated that cofiring
biomass with coal can mitigate some of the fouling difficulties associated with
combinations of biofuels.
Results from NOx measurements made during cofiring experiments of Red Oak Wood Chips with Eastern Kentucky coal are shown. This indicates that slightly more NOx is emitted while cofiring than is predicted by linearly interpolating the results of the reference tests using the fuel mixture. However, it is important to note that total NOx emissions created by cofiring this blend are less than those measured while firing pure coal. The blending of coal with a biofuel that contains little fuel nitrogen such as wood chips should reduce NOx emissions.