MEASUREMENTS OF GAS PARTICLE FLOWS AND ELUTRIATION OF AN 18 INCH ID COLD VORTEXING FLUIDIZED-BED COMBUSTION MODEL

A novel vortexing fluidized-bed combustion (VFBC) technique was recently developed for commercial space/water heating applications. The advantages of VFBC firing solid fuels include large combustion intensity and efficiency, wide turndown and fuel flexibility, and low pollutant emissions. An 18 inch i.d. cold VFBC test model was designed, built, and systematically tested. Measurements of gas flow field, and particle mass fluxes and elutriation under different swirl numbers and secondary air fractions were conducted with mixed-size glass beads. The gas flow field in the VFBC model is characterized by a swirling, developing and recirculating flow. The particle flow field is characterized by alternate layers of dense and dilute circulating suspensions. The VFBC process can substantially reduce the elutriation of particles which was measured to be 3 to 5 orders of magnitude lower than the conventional bubbling FBC operation.