Liquid Holdup and Abnormal Flow Phenomena in Packed Beds under Conditions Simulating the Flow in the Dropping Zone of a Blast Furnace

Fukutake, Tsuyoshi; Rajakumar, V.

doi:10.2355/isijinternational1966.22.355

Cited by 52 publications

(54 citation statements)

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“…The total liquid holdup was found 3.72 % of the total bed volume. The total holdup obtained for this flow rate, from published correlations [23][24][25] was found to be in the range 1.21 to 7.62 %. Holdup obtained from the conventional drainage method 22) was 3.99 %.…”

Section: Validation Of Liquid Holdupmentioning

confidence: 97%

New Calibration Technique for X-ray Absorption Studies in Single and Multiphase Flows in Packed Bed

Basavaraj

Gupta

2004

ISIJ International

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An X-ray technique has been developed to determine the concentration and liquid holdup in a packed bed. To quantify these parameters in single and multiphase flow systems, at local level, a calibration method/graph has been developed. This graph has also been used to obtain the local concentration value of a liquid in presence/absence of another miscible liquid in a porous media. The same graph has been used to quantify the local liquid holdups (static and dynamic) in a packed bed. The same technique can be used for other radiological methods such as gamma rays and neutron radiography. Results obtained from this technique are in agreement with the published data.

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Section: Validation Of Liquid Holdupmentioning

confidence: 97%

New Calibration Technique for X-ray Absorption Studies in Single and Multiphase Flows in Packed Bed

Basavaraj

Gupta

2004

ISIJ International

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“…129,130) For BF operation, such a diagram has been well established. 131) However, previous studies mainly focused on gas-liquid flow in fixed beds. There are a number of factors not properly considered, including, for example, the effects of solid flow and the presence of powder phase.…”

Section: Flooding Diagram and Liquid-powder Interactionmentioning

confidence: 99%

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

et al. 2007

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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...

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“…3,6) Then correlation equations for liquid hold-ups in initially unsoaked bed were derived as follows. F c for initially unsoaked bed is greatly affected by q and d v as above mentioned, and the number of liquid paths within the bed of good wettability is much less than that of bad wettability as shown in Figs.…”

Section: Correlation Equations For Liquid Hold-ups In Ini-mentioning

confidence: 99%

Influence of Channeling Factor on Liquid Hold-ups in an Initially Unsoaked Bed

et al. 2005

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One of the important factors for minimum energy consumption and CO 2 emission of a blast furnace (BF) is to elucidate the liquid flow phenomena and liquid hold-ups in the dripping zone of BF. Liquid hold-ups were studied by using a cold model of a fixed bed soaked prior to experiments (hereinafter called initially soaked bed), but the existing correlation equations derived from liquid hold-ups under initially soaked bed do not agree with liquid hold-ups under initially unsoaked bed such as the dripping zone of BF.In the present study, correlation equations for liquid hold-ups in initially unsoaked bed were experimentally derived by a new approach, in which channeling factor ( F c ) was proposed and defined as follows: F c is the ratio of the number of liquid paths per one horizontal line to the number of voids between particles per the same horizontal line, and was measured by using the moving image of liquid paths photographed by a CCD video camera.By using empirical equation for F c , hold-ups in initially unsoaked bed were described as the following correlation equations.Static hold-up H S(I-UB) (%)ϭ0. , and subscripts I-SB and I-UB designate quantities associated with initially soaked and unsoaked beds, respectively.The comparison with the previous liquid hold-ups shows that the estimated hold-ups are in good agreement with the experimental values for any particle diameters used and both contact angles of 10°and 70°u nder initially unsoaked bed.KEY WORDS: channeling factor; empirical equation; initially unsoaked bed; liquid hold-up; liquid path; blast furnace.ber of voids between particles per the same horizontal line, and was measured by using the moving image of liquid paths photographed by a CCD video camera. Experimental Visualization of Liquid Paths through Initially Unsoaked BedThe visualization method was used in order to investigate liquid flow behavior and to measure F c in initially unsoaked bed. A packed vessel for visualization was two-dimensional model (2D model) with a rectangular parallelepiped made of transparent acrylic resins as shown in Fig. 1. The size of the packed bed is 400 mm in width, 100 mm in depth and 175 mm in height. A liquid distributor of the visualization model installed above the packed bed was composed of 773 injection needles of 0.5 mm I.D. and 25 mm in length to disperse liquid uniformly on the top surface of the packed bed. The filtered tap water was dyed with red ink for easy visualization of liquid paths. Liquid flow behavior and liquid paths were photographed continuously from the front of the packed bed by using a CCD video camera. A digital camera was also used. Solid/liquid contact angles (q) of tap water were about 70°and 10°for fluorine-coated particles and non-coated particles, respectively. In the visualization model, both q decreased to about 65°and 5°, respectively, because the water was dyed with red ink, which is a surface-active agent.To reduce the wall surface effect of the packed column on the liquid flow distribution and hold-ups, the inner surface was ...

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Liquid Holdup and Abnormal Flow Phenomena in Packed Beds under Conditions Simulating the Flow in the Dropping Zone of a Blast Furnace

Cited by 52 publications

References 1 publication

New Calibration Technique for X-ray Absorption Studies in Single and Multiphase Flows in Packed Bed

New Calibration Technique for X-ray Absorption Studies in Single and Multiphase Flows in Packed Bed

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

Influence of Channeling Factor on Liquid Hold-ups in an Initially Unsoaked Bed

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