Solids mixing in a fluidized bed riser
โ Scribed by Chaoyu Yan; Yiping Fan; Chunxi Lu; Yongmin Zhang; Yansheng Liu; Rui Cao; Jinsen Gao; Chunming Xu
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 402 KB
- Volume
- 193
- Category
- Article
- ISSN
- 0032-5910
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โฆ Synopsis
The solids mixing in a riser with a height of 10 m and 0.186 m inner diameter was investigated by using pneumatic phosphor tracer technique. Considering the shielding effect of the bed material on the light emitted from the phosphor tracer particle, a modified method for the phosphor tracer measurement is proposed. And then the curves of particle residence time distribution were obtained. The experimental results show that the particle diffusion mechanism can be explained by the dispersions of dispersed particles and particle clusters in the axial direction, and as well the core-annulus nonuniform distribution of the solids fraction in the radial direction of the riser. Moreover, based on the experimental results, a two-dimensional dispersion model was established to predict the solids axial and radial diffusion. Furthermore, the effects of superficial gas velocity and solids circulating flux on the axial and radial Peclet number of the particles were discussed; two empirical correlation formulas about the axial and the radial Peclet numbers were given; the calculated values agree well with the experimental results.
๐ SIMILAR VOLUMES
Axial and radial segregation effects due to differences in particle sizes and solids densities were studied in a 0.2-m-dia. riser at gas velocities between 3.5 and 7 m/s and solids circulation rates between 8 and 40 kg/(m2.s). Two bed materials (a quartz sand/iron powder mixture and a quartz sand wi
A phenomenological model of axial solids mixing in a circulating fluidized bed is formulated. The model allows for main specific features of the process: ascending motion of particles in the core zone and their descending motion in the annular zone (inner circulation of solids); substantial changes
Abstraet--A new approach to the modelling of gross gas-solids flow through the riser in a circulating fluidized-bed system is proposed in this paper. This approach differs from the previous ones, which are found to be theoretically incorrect based on a fundamental analysis of the riser process hydro
The nano-particles mixing behavior in a nano-agglomerate fluidized bed (NAFB) using R972, a kind of nano-SiO 2 powder, was investigated by the nano-particle coated phosphors tracer method. The axial and radial solids dispersion coefficients in this system were two orders of magnitude lower than thos