Abstract
The fixed-gas drag force from a model calculation method that stabilizes the agitation capabilities of different gas ratios was used to explore the influence of temperature and hydrogen concentration on fluidizing duration, metallization ratio, utilization rate of reduction gas, and sticking behavior. Different hydrogen concentrations from 5vol% to 100vol% at 1073 and 1273 K were used while the drag force with the flow of N2 and H2 (N2: 2 L·min−1; H2: 2 L·min−1) at 1073 K was chosen as the standard drag force. The metallization ratio, mean reduction rate, and utilization rate of reduction gas were observed to generally increase with increasing hydrogen concentration. Faster reduction rates and higher metallization ratios were obtained when the reduction temperature decreased from 1273 to 1073 K. A numerical relation among particle diameter, particle drag force, and fluidization state was plotted in a diagram by this model.
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Abbreviations
- C d :
-
Drag coefficient
- d p :
-
Particle diameter, m
- d pmax :
-
The maximum fluidized particle size, m
- F d :
-
Particle drag force, N
- F dn :
-
Standard particle drag force, N
- M R :
-
Metallization ratio
- M Fe :
-
Metallic iron content
- M RR :
-
Mean reduction rate, s−1
- M R(t) :
-
Metallization ratio at time t
- m :
-
The feeding quantity of Fe2O3, g
- M i , M j :
-
Molar mass of gas components i and j, respectively, kg·mol−1
- R :
-
Fluidized bed inside the diameter, m
- Re :
-
Reynolds number
- T Fe :
-
Total iron content
- t :
-
Reduction time, s
- U g :
-
Gas velocity, m·s−1
- U mf :
-
The minimum fluidization velocity, m·s−1
- V mol :
-
Molar volume, m3·mol−1
- \(V_{H_2 } ,V_{N_2 }\) :
-
The gas flow rate of H2 and N2, respectively, m−3·s−1
- α :
-
Constant
- \(\eta _{H_2 }\) :
-
Hydrogen average utilization rate
- φ ij :
-
Coefficient, the ratio of viscosity to molecular mass of gas components i and j
- ρ g :
-
Gas density, kg·m−3
- ρ p :
-
True density of fluidized particles, kg·m−3
- µg :
-
Gas dynamic viscosity, Pa·s
- µ i , µ j :
-
Dynamic viscosity of gas components i and j, respectively, Pa·s
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Guo, L., Gao, H., Yu, Jt. et al. Influence of hydrogen concentration on Fe2O3 particle reduction in fluidized beds under constant drag force. Int J Miner Metall Mater 22, 12–20 (2015). https://doi.org/10.1007/s12613-015-1037-7
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DOI: https://doi.org/10.1007/s12613-015-1037-7