Effect of agitation on fluidization characteristics of fine particles in a fluidized bed

The effect of agitation on the fluidization characteristics of fine particles was investigated in a fluidized bed with an I.D. of 6 cm and a height of 70 cm. The agitator used was of the pitched-blade turbine type and phosphor particles were employed as the bed material. The particle size was 22 μm and the particle density was 3938 kg/m³. The effect of the agitation speed on the fluidization characteristics was examined by statistical (average absolute deviation (AAD), probability density function (PDF)), spectral (auto-correlation function, power spectrum) and chaos analysis (strange attractor, Hurst exponent, correlation dimension). The results showed that smoother fluidization was observed with increasing agitation speed, because the agglomeration and channeling were reduced by the mechanical agitation. The signals of the pressure drop fluctuation had the shape of a short-term correlation with different agitation speed. The void fraction increased with increasing agitation speed at the constant fluidizing gas velocity.