CFD Modeling and Analysis of Particle Size Reduction and Its Effect on Blast Furnace Ironmaking

Abstract

Particle size reduction inevitably occurs inside ironmaking blast furnaces (BFs) but is not studied under BF conditions due to the lack of an effective tool. This paper simulates this phenomenon inside a 5000-m 3 commercial BF using a recently developed three-dimensional computational fluid dynamics (CFD) process model. In particular, the sinter reduction degradation and coke gasification are modeled for considering the size reduction. By incorporating this information in the BF model, the in-furnace states and global performance are evaluated with respect to sinter reduction degradation index (RDI) under different conditions, e.g., keeping a constant blast rate or gas pressure drop. The results show that with increasing RDI, the bed permeability deteriorates, and there exists a critical value of RDI beyond which the decreased bed permeability leads to a significant drop in productivity for a given gas pressure drop. However, this problem can be mitigated substantially by charging more coke particles at the furnace periphery under the conditions considered. The proposed approach offers an extended capability to model and control BF operations.

Numerical Investigation of the Inner Profiles in Ironmaking Blast Furnace: Effect of the Ratio of Belly Diameter to Effective Height

“…[19] Meanwhile, the model was also applied to capture the trend of global performance factors with respect to blast rate, coke rate, oxygen enrichment, and sinter degradation. [20,21] Furthermore, the change in the deadman profile from symmetric to asymmetric caused by tuyere closure can also be predicted, which is verified by experimental measurements. [21] In addition, the 3D CFD process model is further validated based on the 380 m 3 industrial BF (with R D-H in 0.3311) used in this work.…”

“…The composition, temperature, and flow rate of the reducing gas is determined by local mass and heat conservation under given input conditions, as done by the previous work. [19][20][21] It should be noted that the shape of raceways is determined according to DEM simulations. [26] Their dimensions are determined according to Nomura's empirical correlations.…”

“…[22,23,[29][30][31] However, this model is integrated with our continuous efforts in modeling local phenomena such as layered burden and CZ, deadman, gas, and liquid redistribution by layered CZ and discrete raceway cavities, trickling liquid flow in the dripping zone, particle size reduction, and stockline variation. [18,20,22,[32][33][34]…”

“…[42][43][44] In the currently used BF process model, the submodel to describe the redistribution effect of the CZ on liquid flow is specifically developed and embedded, as described in our previous work. [19][20][21] Figure 12 illustrates the distribution of the liquid mass flow rate under different BF dumpiness. As the BF becomes dumpier, more liquid accumulates at the CZ root near the furnace wall.…”

“…Seven 380 m 3 BFs with R D-H varying from 0.2381 to 0.5172 are simulated to study the effects of different R D-H on BF multiphase flow and thermochemical behaviors using the recently developed computational fluid dynamics (CFD) BF process model. [19][20][21] The inner states, including the cohesive zone (CZ), deadman, distributions of velocity, pressure, temperature, and reaction rate, are analyzed in detail. Meanwhile, an optimal range of R D-H is identified under the conditions considered.…”