The CRF has been involved with a series of laboratory experiments that have examined the influence of cofiring on ash deposition, NO_x production, and fly ash properties using ash deposition and NO_x concentration data collected during cofiring tests of blends of five different fuels. The results demonstrate that rates of ash deposition and NO_x 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 NO_x measurements made during cofiring experiments of Red Oak Wood Chips with Eastern Kentucky coal are shown. This indicates that slightly more NO_x 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 NO_x 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 NO_x emissions.