Study on the Flow Characteristics of Desulfurization Ash Fine Particles in a Circulating Fluidized Bed
Abstract
:1. Introduction
2. Experimental Setup and Particle Properties
2.1. Experimental Setup
2.2. Particle Properties
3. Results
3.1. Distribution of Solids Holdup of Desulphurization Ash Particles
3.2. Influence of Operating Conditions on Solids Holdup of Desulphurization Ash Particles
3.3. Radial Distribution of Particle Solids Holdup, Non-Uniform Distribution
3.4. The Relationship between Particle Flow Parameters and Particle Solids Holdup
4. Conclusions
- (1)
- The solids holdup is relatively high at the riser bottom, gradually decreases with the increase in the axial height, and has a stable value at the top of the riser outlet. The solids holdup is between 0.005 and 0.03. There is also an uneven gas–solids distribution in the radial direction, which may affect the gas–solids contact and thus the efficiency of the desulfurization process.
- (2)
- The superficial gas velocity and the solids circulation rate have different influences on the solids holdup distribution. Changes in the solids holdup in the axial direction are more obvious when the gas velocity is lower, which indicates that the solids holdup is more sensitive to the change in the solids circulation rate at a lower superficial gas velocity. The solids holdup values of different radial regions have different sensitivities to the circulation. At lower gas velocities, the changes in the center and wall regions of the riser are roughly the same. When the superficial gas velocity is higher, the solids holdup of the wall area is more prominently affected by the solids circulation rate than in the center area.
- (3)
- The particle-based Archimedes number has a linear relationship with the solids holdup under all operating conditions.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
Abbreviations
Ars | Archimedes number (-) |
dp | Particle diameter (μm) |
D | Device diameter (m) |
H | Device height (m) |
Gs | Solids circulation rate (kg/m2·s) |
g | acceleration of gravity (m/s2) |
Ug | Superficial gas velocity (m/s) |
z | Height (m) |
ρf | Gas density (kg/m3) |
ρg | Particle density (kg/m3) |
Averaged solids holdup (-) | |
εs | Solids holdup (-) |
μ | Dynamic viscosity of fluidizing air (Pas) |
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Qi et al., 2005 [3] | D: 0.15; H: 3 | 4–5.2 53–489 | FCC | 78 |
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You et al., 2013 [31] | D: 0.305; H: 6 | 1.5 -- | fly ash; river sand | <10, <1000 |
Zhang et al., 2018 [25] | D: 0.305; H: 6 | 2.5 -- | fresh sorbent | 116 |
Chen et al., 2017 [6] | D: 1.2; H: 4.08 | 0.2–0.4 -- | Ca(OH)2 | -- |
Chen et al., 2019 [27] | D: 1.2; H: 4.08 | 3–4 | -- | 0.05–4 |
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Yang et al., 2009 [32] | -- | <3.5 | Ash | 2 |
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Wang et al., 2020 [34] | D: 0.05; H: 2.5 | 2.5 0–15 | Fine particle | 100 |
Particle Size, μm | Volume Fraction, % | Particle Size, μm | Volume Fraction, % |
---|---|---|---|
0–1 | 7.60 | 50–100 | 13.32 |
1–10 | 39.67 | 100–200 | 6.71 |
10–50 | 27.05 | 200–563 | 5.65 |
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Yang, X.; Wang, C.; Lan, X.; Gao, J. Study on the Flow Characteristics of Desulfurization Ash Fine Particles in a Circulating Fluidized Bed. Processes 2021, 9, 1343. https://doi.org/10.3390/pr9081343
Yang X, Wang C, Lan X, Gao J. Study on the Flow Characteristics of Desulfurization Ash Fine Particles in a Circulating Fluidized Bed. Processes. 2021; 9(8):1343. https://doi.org/10.3390/pr9081343
Chicago/Turabian StyleYang, Xiao, Chengxiu Wang, Xingying Lan, and Jinsen Gao. 2021. "Study on the Flow Characteristics of Desulfurization Ash Fine Particles in a Circulating Fluidized Bed" Processes 9, no. 8: 1343. https://doi.org/10.3390/pr9081343