Fine Particulate Formation During Biomass/Coal Cofiring

Experiments to examine the effects of biomass/coal cofiring on fine particle formation were performed in the Sandia Multi-Fuel Combustor using fuels of pure coal, 3 combinations of switchgrass and coal, and pure switchgrass. A constant thermal input was maintained. The combustion products were cooled during passage through the 4.2 m long reactor to simulate the temperatures experienced in the convection pass of a boiler. Fine particle number densities, mass concentrations, and total number concentrations for particles between 10 nm and 1 μm at the reactor exit were determined using a Scanning Mobility Particle Sizer. The results indicate that the fine particle loading for cofiring is higher than that achieved with dedicated coal combustion but lower than that achieved with dedicated switchgrass combustion.