Effects of fine particles and external moisture on the pressure fluctuations in the gas-solid fluidized bed beneficiator

Journal article, 2026

External moisture and fine particles significantly affect fluidization dynamics. In this study, we discuss the effects of external moisture, fine particle content and superficial gas velocity on the fluidization dynamics of Geldart Group B particles by analyzing the pressure fluctuations in a gas–solid fluidized bed coal beneficiator. The results indicate that the mean frequency increases with rising superficial gas velocity and fine particle content, although the growth rate gradually levels off. In contrast, increasing moisture content leads to a gradual decline in mean frequency with an accelerating rate of decrease. The mean frequency exhibits the lowest sensitivity to changes in external moisture, while that with superficial gas velocity is the largest. Power spectral density analysis further identified signal characteristics associated with poor fluidization. Wavelet decomposition of the pressure signals revealed that the 6.25–1.5625 Hz frequency range plays a crucial role in characterizing the fluidization behavior of wet Geldart B particles with a wide size range. Integrated PSD and wavelet analyses demonstrate that increasing superficial gas velocity helps mitigate the effects of fine particles and external moisture on destabilizing fluidization.