화학공학소재연구정보센터
Advanced Powder Technology, Vol.29, No.11, 2591-2600, 2018
Characterization of temporal and spatial distribution of bed density in vibrated gas-solid fluidized bed
This study uses a Phi 200 mm x 900 mm vibrated gas-solid fluidized bed (VGFB) with -0.3 + 0.074 mm magnetite powder was utilized to characterize the temporal and spatial distribution of bed density in VGFB and the influence of bubble movement on fluctuations in bed density. The results indicate that the bed density decreases with an increase in gas velocity (U) and the frequency (f) and amplitude (A) of vibration and that the bed density spatial distribution is lower in the central region but higher in the border regions. The standard deviation of the density first increases then decreases and finally tends to stabilize with an increase in apparent gas velocity. Moreover, when A = 2 mm, f = 25Hz and U = 14 cm/s, the density distribution is 1.82-1.88 g/cm(3) and the fluidization state is improved. The energy of the pressure signal increases with an increase in gas velocity and vibration amplitude. In particular, the low-frequency band of the pressure signal exhibits the highest amplitude and energy, which reveals that bubbles are the main cause of pressure fluctuation. Furthermore, the bed density decreases with an increase in bubble generation frequency, and the relationship between these follows the ExpDec 2 mathematical equation. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.