Numerical Analysis of Static Holdup of Fine Particles in Blast Furnace

Pintowantoro, Sungging; Nogami, Hiroshi; Yagi, Jun‐ichiro

doi:10.2355/isijinternational.44.304

Cited by 25 publications

(18 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23) Deficiencies in these studies are inherited in mathematical modelling, including, for example, the ignorance of the static holdup, the use of a relatively simple packing structure, and different interaction force equations. In order to overcome these deficiencies, various experimen-tal 24,40,[100][101][102][103][104] and numerical 21,38,[40][41][42]96,[105][106][107][108][109] efforts have been made by various investigators in recent years.…”

Section: Gas-powder Flowmentioning

confidence: 99%

“…1) Since the 1990s, significant progress has been made in this area, mainly due to improved computational capability. These developments include: i) inclusion of more phases 38,134) and more chemical species and chemical reactions 135) in the BF modelling; ii) development of models to take into account the dynamic and static holdups for liquid and powder phases 108,126,136) ; and iii) implementation of more comprehensive models, e.g. three-dimensional steady 137) or transient 26,138) model.…”

Section: Process Simulationmentioning

confidence: 99%

“…The static powder holdup or powder transported by packed particles, is obtained using empirical correlations 41,113) or calculated by material balances using empirical expressions on powder deposition rate and equilibrium static holdup. 108,109) In some cases, powder may deposit in regions of low gas velocity, where the void space among packed particles can be completely filled with powder. This region is referred to as the powder accumulation region, which has the maximum powder holdup and will not allow any powder to penetrate.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

et al. 2007

Self Cite

View full text Add to dashboard Cite

An ironmaking blast furnace is a complex multiphase flow reactor involving gas, powder, liquid and solid phases. Understanding the flow behaviour of these phases is of paramount importance to the control and optimization of the process. Mathematical modelling, often coupled with physical modelling, plays an important role in this development. Yagi 1) gave a comprehensive review of the early studies in this area in 1993. Significant progress has since been made, partially driven by the needs in research but mainly as a result of the rapid development of computer and computational technologies. This paper reviews these developments, covering the formulation, validation and application of mathematical models for gas-solid, gas-liquid, gas-powder and multiphase flows. The need for further developments is also discussed.KEY WORDS: ironmaking; blast furnace; multiphase flow; two fluid model; discrete element method. Review development. Mathematical ModellingGenerally speaking, the existing approaches to modelling the multiphase flow in a BF can be classified into two categories: continuum approach at a macroscopic level and discrete approach at a microscopic level. In the continuum approach, phases are generally considered as fully interpenetrating continuum media and described by separate conservation equations with appropriate constitutive relations and interaction terms representing the coupling between phases. The general governing equations are based on the so-called two fluid model (TFM), originally developed for gas-particle flow, [29][30][31] given by:Conservation The so-called Model A and Model B result from the treatment of the fluid pressure. For example, for gas-solid flow, Model A assumes the pressure is shared between the two phases, while in Model B, the pressure is attributed to gas phase only. 31) Model A formulation has been widely used in multiphase modelling, especially in process metallurgy. Model B formulation was recently used in the so called combined continuum and discrete method for coupled flow of continuum fluid and discrete particles. 32) The continuum approach is suitable for process modelling and applied research because of its computational convenience and efficiency. Indeed, most of the BF modelling is based on this approach. However, its effective use heavily depends on constitutive or closure relations and the momentum exchange between phases. For Newtonian fluids (gas and liquid here), these relations can be readily determined. For non-Newtonian fluids such as solids and powder, general theories are not yet available. In the past, various theories have been devised for different flow regimes (three flow regimes have been identified: quasi-static regime, rapid flow regime and a transitional regime that lies inbetween). For example, models have been proposed to derive the constitutive equations for the rate-independent deformation of granular materials based on either the plasticity theory or the double shearing theory; the rapid flow of granular materials has been described by extend...

show abstract

Section: Gas-powder Flowmentioning

confidence: 99%

Section: Process Simulationmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…[17][18][19][20][21] Recently these models included accumulated powder (static hold-up) as a new phase to analyze powder deposition behavior of powder in blast furnace and granular bed filter. [22][23][24] Although these models provided the useful information and expectations, simultaneous handling of the pulverized coal and the fine coke with dynamic-static separation has yet to be reported. In this study a multi-fluid based operation simulator of blast furnace including this feature and heat transfer and chemical reactions regarding accumulated powders was developed, and this new mathematical model was applied to the actual blast furnace operation to examine the behaviors of the unburned char and the fine coke in the blast furnace.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis on Behavior of Unburned Char and Fine Coke in Blast Furnace

2005

Self Cite

View full text Add to dashboard Cite

A mathematical model of blast furnace operation, which is able to estimate the behaviors of the unburned char and the fine coke simultaneously, has been developed. The model based on the multi-fluid theory treats dynamic powders that are moving entrained by the gas stream as individual phases and static powders as solid components. The former takes conservation equations of momentum, thermal energy, chemical species and continuity. The latter takes only mass balance equations of chemical species, and shares fields of flow and temperature with the other solid components, such as lump coke, sinter, and so on. In the simulations, the unburned char is derived from the pulverized coal injected from the tuyere, and there is no difference in model treatment between the unburned char and the pulverized coal. The fine coke is generated uniformly in the raceway region from the coke particles, and the generation rate is determined by a kinetic treatment. The simulation of the blast furnace operation by this model revealed that the unburned char and the fine coke having different diameters and densities show different flow patterns especially in the cohesive zone and deadman. Consequently these two powders formed different areas of accumulation and reactions while large amount of powders were deposited in the deadman zone regardless of difference in flow patterns.

show abstract

“…To control accumulation of these materials, it is necessary to clarify powder deposition, reentrainment, consumption, transport and generation. A method to discuss powder accumulation is a kinetic based mathematical model [1][2][3][4][5][6] and this technique is able to show the powder flow behavior, hold-up distribution, pressure drop, and so on. The authors' work 6) pointed out the heavy and large particles, namely coke fragments, were easy to deposit within the packed bed in the blast furnace.…”

Section: Introductionmentioning

confidence: 99%

Effect of Solution Loss Reaction on Coke Degradation Rate under Sheer Stress

2004

Self Cite

View full text Add to dashboard Cite

The degradation behavior of spherical coke samples was measured under sheer stress. The samples underwent the solution loss reaction until various degrees in several reaction temperatures (10-30 wt% and 1 273-1 573 K). A sample is settled between two horizontal boards with parallel grooves like washboard. The sheer stress was applied to the sample by sliding upper board at a certain cycle with a constant vertical load. The generated powder was sieved and weighed, and the appearance of the coke sample was observed. From the measurement of the powder generation rate and discussion on the reaction mode of the solution loss reaction, the degradation behavior can be explained by the distribution of local reaction degree within a coke particle. The powder generation rate from the samples reacted in lower temperature increases with increase in overall reaction degree because the reaction of coke substrate with carbon dioxide, namely the strength deterioration, proceeds in entire particle. The high temperature samples show little increase in the powder generation with the overall reaction degree since the surface reaction mode increases local reaction degree in the vicinity of particle surface and this reacted layer is also consumed from the surface. This dependency of the powder generation behavior on the reaction mode of the solution loss reaction measured in this study corresponds to the previously reported behavior in the raceway zone regardless of grinding mechanism. Therefore, it is considered that the single-particle degradation test of coke is an appropriate method to measure the degradation behavior of a coke particle under sheer stress.

show abstract

Numerical Analysis of Static Holdup of Fine Particles in Blast Furnace

Cited by 25 publications

References 2 publications

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

Modelling of Multiphase Flow in a Blast Furnace: Recent Developments and Future Work

Numerical Analysis on Behavior of Unburned Char and Fine Coke in Blast Furnace

Effect of Solution Loss Reaction on Coke Degradation Rate under Sheer Stress

Contact Info

Product

Resources

About