Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2

circulating fluidized bed Related Publications

2 Correlation to Predict the Effect of Particle Type on Axial Voidage Profile in Circulating Fluidized Beds

Authors: S. Khan, M. S. Khurram, S. A. Memon

Abstract:

Bed voidage behavior among different flow regimes for Geldart A, B, and D particles (fluid catalytic cracking catalyst (FCC), particle A and glass beads) of diameter range 57-872 μm, apparent density 1470-3092 kg/m3, and bulk density range 890-1773 kg/m3 were investigated in a gas-solid circulating fluidized bed of 0.1 m-i.d. and 2.56 m-height of plexi-glass. Effects of variables (gas velocity, particle properties, and static bed height) were analyzed on bed voidage. The axial voidage profile showed a typical trend along the riser: a dense bed at the lower part followed by a transition in the splash zone and a lean phase in the freeboard. Bed expansion and dense bed voidage increased with an increase of gas velocity as usual. From experimental results, a generalized model relationship based on inverse fluidization number for dense bed voidage from bubbling to fast fluidization regimes was presented.

Keywords: circulating fluidized bed, axial voidage, splash zone, static bed

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1 Cold Model Experimental Research on Particle Velocity Distribution in Gas-Solid Circulating Fluidized Bed for Methanol-to-Olefins Process

Authors: Hongfang Ma, Yongzheng Li, Weiyong Ying, Haitao Zhang, Qiwen Sun

Abstract:

Radial profiles of particle velocities were investigated in a 6.1m high methanol-to-olefins cold model experimental device using a TSI laser Doppler velocimeter. The effect of axial height on flow development was not obvious in fully developed region under the same operating condition. Superficial gas velocity and solid circulating rate had significant influence on particle velocity in the center region of the riser. Besides, comparisons among rising, descending and average particle velocity were conducted. The particle average velocity was similar to the rising particle velocity and higher than the descending particle velocity in radial locations except the wall region of riser.

Keywords: circulating fluidized bed, laser doppler velocimeter, particle velocity, radial profile

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