(434f) Visualization of Combustion of Solid Fuel Particles in a Drop Tube Furnace

A laboratory-scale drop tube furnace was designed to maximize visualization capability for combustion of fuel particles and droplets in combustion environments with a high degree of control of temperature, pressure, and gas composition. The furnace operates at temperatures up to 1,200°C and it has three independent temperature zones. The drop tube retort is transparent quartz with a diameter of 6 cm and a length of 80 cm; three vertical 25 cm rectangular windows in the furnace casing allow visualization access to particles as they combust at various distances from a water-cooled injection nozzle.

Results will be presented for single particle combustion of samples of pulverized coal, wood chips, and switch grass. The combustion of individual particles in the furnace was visualized with a high-speed camera and a high magnification lens system. Video provides qualitative comparison of combustion events, and still images were analyzed to measure surface temperature distributions and burn properties for the particles. Results will be presented for 100 micron particles undergoing combustion at 900°C. The fuels, particle sizes, and operating conditions of the furnace were selected to evaluate effectiveness of these alternative fuels in comparison to coal for application in cement production.