Entrainment of fine particles with upward gas flow in a packed bed of coarse particles

Hidaka, Nobuyuki; Iyama, Junji; Matsumoto, Tsunekazu; Kusakabe, Katsuki; Morooka, Shigeharu

doi:10.1016/s0032-5910(97)03357-3

Cited by 41 publications

(33 citation statements)

References 10 publications

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“…The volume fraction of the entrained powder is referred to as the dynamic holdup, and the entrapped powder as the static holdup. In this work, it is assumed that the static powder is quantified by the following equation, modified from that of Hidaka et al [19]: This equation implies that there is a maximum powder holdup e max f that corresponds to the situation when the voids among packed particles are fully occupied by powder particles. A region with maximum holdup, i.e.…”

Section: Boundary Conditions and Numerical Solutionmentioning

confidence: 99%

Gas-powder flow in blast furnace with different shapes of cohesive zone

Dong

Pinson

Zhang

et al. 2006

Applied Mathematical Modelling

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With high PCI rate operations, a large quantity of unburned coal/char fines will flow together with the gas into the blast furnace. Under some operating conditions, the holdup of fines results in deterioration of furnace permeability and lower production efficiency. Therefore, it is important to understand the behaviour of powder (unburnt coal/char) inside the blast furnace when operating with different cohesive zone (CZ) shapes. This work is mainly concerned with the effect of cohesive zone shape on the powder flow and accumulation in a blast furnace. A model is presented which is capable of simulating a clear and stable accumulation region in the lower central region of the furnace. The results indicate that powder is likely to accumulate at the lower part of W-shaped CZs and the upper part of V-and inverse V-shaped CZs. For the same CZ shape, a thick cohesive layer can result in a large pressure drop while the resistance of narrow cohesive layers to gas-powder flow is found to be relatively small. Implications of the findings to blast furnace operation are also discussed.

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Section: Boundary Conditions and Numerical Solutionmentioning

confidence: 99%

Gas-powder flow in blast furnace with different shapes of cohesive zone

Dong

Pinson

Zhang

et al. 2006

Applied Mathematical Modelling

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“…These experimental works can be generally classified in three groups. First group [6][7][8][9][10][11][12] formulated the interaction forces among gas, powder and packed particle based on the macroscopic information under the steady state condition. Second one [13][14][15] formulated the interaction force by taking into account the variation of the powder particle velocity in the packed bed.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis on Passage and Blockage Behaviors of Fine Particles through an Orifice Consists of Coarse Particles

et al. 2015

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Stable operation under low reducing agent rate condition of blast furnace is necessary to realize to contribute solution of global warming. Under low reducing agent rate operation, large amount of powder materials like fine coke and unburnt pulverize coal generate in the furnace. It is known that the heavy accumulation of these powders in the packed bed of blast furnace deteriorates the permeability, and cause operation trouble in extreme case. Thus it is important to understand the flow and accumulation behaviors of powder in packed bed. This paper discussed the powder motion in the packed bed through numerical simulation under simplified condition. A simplified packing structure, namely an orifice consisting of three spherical particles that touched each other and were in equilateral triangle arrangement, was picked out from the packed bed. The powder trajectories passing through this orifice were tracked by using the discrete element method. The simulation results showed that only a few powder particles initiated the blockage of the particle orifice. Additionally the effects of mechanical properties of the particles on the passage and the blockage behaviors were also revealed.KEY WORDS: powder; blockage; packed bed; blast furnace; discrete element method.

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“…13,14) Other experimental investigations also include visual characteristics of the powder accumulation. 15,16) Theoretical models for the accumulation of the injected powders, based on visual observations of a blast furnace cold model cross section 16) or on experiments covering a wide range of conditions, [17][18][19] have also been developed. However, classically studies on deposition of aerosol filtration are concentrated mainly in the collection efficiency of fibrous and granular bed filters.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Model of Over-micron and Nano-scale Powders Accumulation in a Coke Fixed-Bed Filter

et al. 2005

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The advances in Electric Arc Furnace (EAF) dust treatment have been slowed down by high treatment costs and the large amount of residue to be processed and disposed. A process of direct separation and recovery of iron and zinc is now under development, which adds environmental and economical perspectives to the EAF dust treatment process. In this process, a coke bed filter can be directly connected to an EAF, collecting metallic iron and slag components, whereas the gas containing zinc and lead vapors flows to a zinc condenser. It results in zero amount of dust liberated to the environment. A two dimensional, axisymmetric and steady state mathematical model describing a coke fixed-bed filter is developed. The model solves coupled equations for gas-powder flow and is specifically applied in the investigation of over-micron and nano-scale powders (similar to EAF dust particle size) collection behavior. The theoretical model results are compared with the cold model experimental results, in which both injection of glass (over-micron) and silica (nano-scale) powders are considered. Microscopic observations and analysis are performed in order to describe better the injected powder behavior through the filter. EAF dust samples morphology is characterized as agglomerates of small particles. Its particle size distribution is obtained by the combination of leaching treatment and image analysis. Calculated results show that the powders particle size distribution has a direct effect in the static hold up. The model has been validated by its enough agreement for static hold up and pressure drop with experimental data from cold model experiments.KEY WORDS: mathematical model; Electric Arc Furnace; dust treatment; environment; packed bed; filter.have advanced for more detailed investigations, e.g. including the effect of the temperature, 23) the presence of an electrified field, 24) or the effect of the aerosol deposition on the filtration. 25) A model equation adapted from the theory for a fibrous filter, describing the dust load distribution in a coke bed filter, has also been recently developed and tested. 26)The aim of this research is contribute to the development and improvement of the process of direct separation and recovery of iron and zinc, testing and analyzing its efficiency and effectiveness. The physical modeling of the packed bed filter had provided a series of experimental results about pressure drop and the powder collection. [27][28][29][30][31][32] In this work a mathematical model of a cold coke fixed-bed filter has been developed. This model is used to investigate the powder accumulation behavior and pressure drop with the injection of over-micron and nano-scale powders in a packed bed. The mathematical model developed here is expected to be the framework for simulation of a high-temperature coke fixedbed filter and further on to study different aspects of this process. Microscopic Observations and AnalysisDue to lack of information about aerosol collection in packed bed filters, including the theoretical ...

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Entrainment of fine particles with upward gas flow in a packed bed of coarse particles

Cited by 41 publications

References 10 publications

Gas-powder flow in blast furnace with different shapes of cohesive zone

Gas-powder flow in blast furnace with different shapes of cohesive zone

Numerical Analysis on Passage and Blockage Behaviors of Fine Particles through an Orifice Consists of Coarse Particles

Mathematical Model of Over-micron and Nano-scale Powders Accumulation in a Coke Fixed-Bed Filter

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