Conference Dates

May 22-27, 2016


A Magnetic Particle Tracking (MPT) system is used to experimentally characterize the vertical distribution of fuel particles in a fluidized bed. The measurements are carried out in a fluid-dynamically down-scaled cold unit resembling a 1×1 m2 boiler operating at 850 °C. The MPT system yields spatial and temporal information of the tracer particle with accuracies in the order of 10-3 m and 10-3 s, respectively. The MPT system is used to study how fuel segregation is influenced by physical properties of the fuel (sizes and densities representing different fuel types) and operational conditions, such as fluidization velocity, bed height and pressure drop across the gas distributor.

For the range of fluidization velocities investigated, the results show two fuel segregation regimes: 1) a low-velocity mixing-regime, for which the presence of fuel particles at the dense bed surface and splash zone decreases strongly with increased fluidization velocity, and 2) a high-velocity mixing-regime where the presence of fuel at the bed surface and the splash zone increases with fluidization velocity, but with a weaker dependence than in the low-velocity regime. The fluidization velocity separating the two regimes depends on bed height and fuel properties.