The qualitative effect of temperature on the particle entrainment rate has been measured in a gas fluidized bed (0.1 m i.d., 1.97 m height). The gas velocity (0.65-2.3 m/s), the bed temperature (12-600 °C), the particle density (2509-6158 kg/m 3 ), and the particle size (0.091-0.363 mm) were considered as experimental variables. The particle entrainment rate increased after an initial decrease with increasing bed temperature. The effect of temperature on particle entrainment rate decreased as either the gas velocity or the particle density increased. Within the experimental range, it could be confirmed that the change of the particle entrainment rate with temperature was very similar to that of the particle size for which the terminal velocity was equal to the gas velocity.

No abstract

No abstract

An empirical correlation, considering the temperature effect but no effects of interparticle forces, on the particle entrainment rate at the gas exit of the fluidized bed has been proposed on the basis of the comprehensive experimental data. The entrainment flux is considered to consist of a constant flux independent of freeboard height and another flux decreasing exponentially with freeboard height. The correlation successfully follows the measured trend where the entrainment rate increased after an initial decrease with increasing temperature and the minimum entrainment rate at a given temperature. The correlation also successfully describes the pressure effect showing that the entrainment rate increases with pressure.