Operation of Blast Furnace at the Condition of Low Fuel Rate

Togino, Yuji; Tateoka, Masatake; Sugata, Masayasu; Yamaguchi, K.; Kume, Shoichi; Yamaguchi, Kazuyoshi; Abe, Isao

doi:10.2355/tetsutohagane1955.65.10_1553

Cited by 7 publications

(3 citation statements)

References 3 publications

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“…The figures show there is a critical minimum distance between the simulated cohesive-zone and deadman surface below which the discontinuity become large, which may correspond to the result obtained from the test operations of blast furnaces. 1,2) Figure 10 demonstrates again charging the material of high gas-permeability at the central part is favorable.…”

Section: (5) the Span Of Funnel Flow Channel And Discontinuitymentioning

confidence: 99%

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Two Dimensional Cold Model Study on Unstable Solid Descending Motion and Control in Blast Furnace Operation with Low Reducing Agent Rate

2005

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Unsteady behavior with bridging/slipping of solid bed in low reducing agents rate operation of blast furnace was simulated using a two dimensional cold model. Alumina sphere was used as representative particle of coke/ore packed bed. Two kinds of deadman particles different in gas permeability was examined. To simulate the effect of cohesive zone on unsteady behavior, a sand layer of lower gas-permeability was charged with a certain thickness at the top of the bed, which descended with a form of cohesive zone when it reached at the lower part. Further, a fine coke layer was set at the shaft bottom with a certain size assuming accumulation of fines. Unsteady phenomenon with the fine coke accumulation was observed with another thin sand layers, charged in the shaft assuming increase of gas-permeability resistance in lower reducing agents rate operation. It was revealed that the ratio of peripheral flow rate to the total gas injection rate had a considerable effect on the discontinuous behavior of both solid descending motion and gas static pressure. The ratio increased with decline in deadman gas-permeability, approach of the simulated cohesive zone to deadman surface and inflow of small particles into raceway. There was a lowest critical position of the simulated cohesive zone for the rapid increase of discontinuity. The bridging/slipping behavior with fines accumulation was significantly affected by the low gas-permeability layers charged in shaft. Setting up the chimney zone of high gas-permeability at the central part was effective to decrease the discontinuous motion.KEY WORDS: blast furnace; low reducing agents; moving bed; solid flow; unstable solid behavior; bridging; slipping.On the background stated above, the purpose of this investigation is to simulate experimentally the unstable behavior of packed bed including bridging/slipping using a two dimensional cold model of blast furnace. A technique with a solid particle bed of lower gas-permeability, initially charged as a horizontal layer and descends with a form as if it were cohesive zone when it reaches at the lower part of the model furnace, is adopted in order to evaluate the effect of the size of coke funnel-flow channel on the unstable bed motion. Further, setting initially a fine coke layer at the bottom of the shaft assuming accumulation of the fines, the experiment is carried out with a technique simulating the decline in gas-permeability in the upper part of the blast furnace. The relationship between fine-solid inflow to raceway and unstable packed-bed motion is also investigated on the view that the fine-solid inflow would decrease the gas permeability from raceway to surrounding packed bed. The measurement to detect the unstable bed motion is carried out while the solid material used for the above-mentioned purposes descends to reach the raceway and flows in it. The methods for controlling the instability of solid flow are also suggested. ExperimentA two-dimensional, half model of blast furnace consisting of transparent, acrylic resin sheets,...

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Section: (5) the Span Of Funnel Flow Channel And Discontinuitymentioning

confidence: 99%

“…The bridging/slipping phenomenon is supposed to be related deeply with the thickness of the coke funnel flow channel. 1,2) The flame brightness observed from tuyere fluctuates in cycles. 2) Concerning this phenomenon, the cyclic inflow of coke or coke/ore mixture to raceway is suggested.…”

Section: Introductionmentioning

confidence: 99%

Two Dimensional Cold Model Study on Unstable Solid Descending Motion and Control in Blast Furnace Operation with Low Reducing Agent Rate

2005

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“…3 BF with a monthly average fuel ratio of 428.2 kg/t-HM 4) and Kimitsu No. 3 BF reaching a fuel ratio of 431 kg/t-HM 5) and in the high productivity case of Keihin No. 2 BF up to 2.69 t/m 3 in productivity, 6) it is shown that the center gas flow is fairly high and the gas temperature in the peripheral part is comparatively higher than the intermediate part.…”

Section: Introductionmentioning

confidence: 99%