Liquid Holdups and Abnormal Flow Phenomena of the Gas-liquid Counter-current Flow in Packed Beds under Simulating Conditions of the Flow in the Dropping Zone of a Blast Furnace

Fukutake, Tsuyoshi; Rajakumar, V.

doi:10.2355/tetsutohagane1955.66.13_1937

Cited by 37 publications

(32 citation statements)

References 15 publications

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“…Figure 1 shows that total hold-up (H t ; ᭺) and static hold-up (H S ; ᭝) for initially unsoaked bed are remarkably smaller than those (᭹, ᭡) for initially soaked bed, but dynamic hold-ups for initially unsoaked and soaked beds (H d ; ᮀ, ) are similar to each other. H S (᭡) for initially soaked bed is almost independent of the liquid velocity (superficial velocity V L ) and shows practically constant value, which agrees with an equation by Fukutake et al 6) However, H S (᭝) for initially unsoaked bed lies remote from the calculated one. The liquid flow distributions through 2D model of initially soaked and unsoaked fixed beds are shown in Fig.…”

Section: Introductionsupporting

confidence: 79%

“…Thus, it is obvious that the effective area of the particles contacted with liquid droplets and/or liquid rivulets under the condition of bad wettability is much larg- er than that in the condition of good wettability through initially unsoaked bed. Generally, total and static hold-ups increase with decreasing contact angle, 6) because liquid is easy to spread out on the solid surface in the case of good wettability. Under initially unsoaked bed, however, it can be recognized from the above-mentioned liquid flow behavior that total and static hold-ups decrease with decreasing contact angle, because the liquid dispersed uniformly on the top surface of the packed bed is difficult to spread out within the packed bed and flows down in the restricted liquid paths.…”

Section: Visualization Of Liquid Flow Behaviormentioning

confidence: 99%

“…6) Uniformly dispersed liquid on almost all the top surface of the packed bed, however, forms liquid droplets and/or liquid rivulets in some part of the packed bed, from which a few liquid paths branch out. Then liquid droplets and/or liquid rivulets are easy to flow through the same path, pulling each other by their own surface tension.…”

Section: Effect Of Contact Angle On Hold-ups In Initiallymentioning

confidence: 99%

“…In most previous works [2][3][4][5][6] liquid hold-ups were investigated by using a cold model of a fixed bed which was soaked prior to experiments (hereinafter called initially soaked bed). The characteristics of liquid hold-ups for BF should be investigated by using a moving bed unsoaked prior to experiments (hereinafter called initially unsoaked bed), because the burden continually descends and is not completely wetted in the lower part of BF.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of Liquid Hold-ups in a Soaked and Unsoaked Fixed Bed

Kawabata¹,

Liu²,

Fujita³

et al. 2005

ISIJ Int.

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In most previous works, liquid hold-ups were studied by using a cold model of a fixed bed soaked prior to experiments. However, they did not consider that the dripping zone of a blast furnace is saturated with liquids or with evenly distributed droplets. In the present study, the characteristics of liquid hold-ups and liquid flow were investigated by using a one-dimensional cold model of a fixed bed soaked and unsoaked prior to experiments (initially soaked and unsoaked beds). Packed balls were five kinds, the diameters (D p ) of which ranged from 5.4 to 30 mm. Tap water was used as liquid. Contact angles (q) for these particle/liquid systems were about 70°and 10°for fluorine-coated particles and non-coated particles, respectively.Although, under bad wettability condition (q Լ 70°), total and static hold-ups for initially unsoaked bed packed with small balls are remarkably smaller than those for initially soaked bed, the difference in their hold-ups between initially unsoaked and soaked beds decreases with increasing ball size in the bed. In initially soaked bed, total and static hold-ups increase monotonically as ball size decreases, which means the specific surface area increases. On the other hand, in initially unsoaked bed, total and static hold-ups under bad wettability condition indicate maximum values at about D p ϭ10 mm and decrease abruptly in proportion to a decrease in particle size, despite an increase in the specific surface area. Only restricted liquid droplets and/or liquid rivulets are formed within the packed bed with good wettability condition (qԼ 10°) for initially unsoaked bed, nevertheless liquid is easy to spread out on the solid surface. The influence of the initial bed condition, soaked or unsoaked bed, on liquid hold-ups is great under bad wettability condition.KEY WORDS: ironmaking; blast furnace; dripping zone; fixed bed; liquid hold-ups; particle/liquid wettability; initially soaked and unsoaked beds.

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Section: Introductionsupporting

confidence: 79%

Section: Visualization Of Liquid Flow Behaviormentioning

confidence: 99%

Section: Effect Of Contact Angle On Hold-ups In Initiallymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characteristics of Liquid Hold-ups in a Soaked and Unsoaked Fixed Bed

Kawabata¹,

Liu²,

Fujita³

et al. 2005

ISIJ Int.

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“…8) Figure 5 is the Sherwood diagram made from the previous data. 9) We plotted our data on this diagram. When the flooding factors for our data are calculated by using the specific area of particle (᭺), the values are lower than the data of previous studies.…”

Section: Effect Of Packed Structure On Gas Velocities Atmentioning

confidence: 99%

Effects of Packed Structure and Liquid Properties on Liquid Flow Behavior in Lower Part of Blast Furnace

et al. 2005

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Supposing liquid flow in the lower part of the blast furnace, a small trickle bed with abnormal void was used, and the effects of packed structure and liquid properties on the liquid flow behavior were examined. Different-size glass particles coated with PTFE (polytetrafluoroethylene) were packed in the column, and the pressure loss and liquid holdup in the packed bed were measured. The liquid loading and flooding points were obtained from the change in pressure loss.Both the gas velocities at loading and flooding points decreased with increasing volume fraction of small particle, with increasing liquid viscosity and with increasing liquid velocity. As the small particle fraction is higher, the total and static liquid holdups increase but the dynamic one decreases. These holdups were expressed by the experimental equations.The liquid behavior in one void was modeled and analyzed. From the force balance on the liquid droplet at the flooding point the upward and downward forces were examined, and the variation in liquid flow behavior in the lower part of the blast furnace was estimated.

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Capturing the non‐spherical shape of granular media and its trickle flow characteristics using fully‐Lagrangian method

et al. 2016

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We performed a numerical analysis for simulating granular media structures containing non‐spherical elements and the liquid trickle flow characteristics of such structures. Fully‐Lagrangian numerical simulation methods can track all motion information for solid or liquid elements at each point in time. We introduced suitable compressibility to moving particle semi‐implicit (MPS) and performed individual packing behavior calculations for non‐spherical elements, based on discrete element method (DEM) with expanded functions. Rigid bodies‐DEM is a method using a DEM contact force model that is expanded to handle the motion of freely shaped solids. It expresses complex shapes to enable low calculation costs and intuitive mounting. We used the boundary for the granular media configured with non‐spherical elements to implement a trickle flow simulation based on weakly compressible‐MPS. Even for elements of equal volume, different shapes changed the liquid passage velocity and hold‐up amount. The mean downflow velocity of the liquid phase was not always dependent on the void fraction. For the plane of projection, we obtained a good correlation with the mean downflow velocity in each packed structure, and successfully performed arrangements according to the new liquid‐passage shape coefficient. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2257–2271, 2017

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Liquid Holdups and Abnormal Flow Phenomena of the Gas-liquid Counter-current Flow in Packed Beds under Simulating Conditions of the Flow in the Dropping Zone of a Blast Furnace

Cited by 37 publications

References 15 publications

Characteristics of Liquid Hold-ups in a Soaked and Unsoaked Fixed Bed

Characteristics of Liquid Hold-ups in a Soaked and Unsoaked Fixed Bed

Effects of Packed Structure and Liquid Properties on Liquid Flow Behavior in Lower Part of Blast Furnace

Capturing the non‐spherical shape of granular media and its trickle flow characteristics using fully‐Lagrangian method

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