Reducing Gas Injection into Furnace Stack in an Experimental Furnace

Miyashita, Tsuneo; Nishio, Hiroaki; Simotsuma, Teruo; Yamada, Takeo; Ohotsuki, Mitsuru

doi:10.2355/tetsutohagane1955.58.5_608

Cited by 17 publications

(17 citation statements)

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“…It is thought that the penetration region of gas is almost dominated by the momentum distribution because the diffusion distance of injected gas is much smaller than that of convection effect. [1][2][3][4] From Fig. 5, the influence of shaft gas injection was observed around the injection level in each case.…”

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confidence: 99%

Dynamic Analysis of Gas and Solid Flows in Blast Furnace with Shaft Gas Injection by Hybrid Model of DEM-CFD

et al. 2011

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where, e, n n, p, r g and m g denote the void fraction, velocity vector, pressure, density, and viscosity of a fluid, respectively. The local void fraction is obtained from the particle locations calculated by DEM. The source term f g takes into account the interaction force between fluid and particles.The gas flow equations are common to the gas from ordinal tuyere and auxiliary tuyere at shaft gas injection. Particle-Fluid InteractionWhen the calculation region is divided into microscopic cells in order to calculate the gas flow in the blast furnace, the fluid velocity is treated as superficial velocity in Eqs.(12) and (13). In this study, the void fraction in the packed bed is calculated from the location of the particles obtained as a result of the particle movement analysis by DEM. The pressure drop is expressed by the multi-dimensional Ergun's equation for a packed bed. 13,14) In this study, only the gas velocity is considered, as it was assumed that the particle velocity in the packed bed is sufficiently small in comparison with the gas velocity.... (14) where, d p denotes the representative particle diameter in a cell. The pressure drop in the cell is considered to be the total of the momentum exchange of the particles. Therefore, a cluster particle used in DEM receives the total drag forces of the actual particles which are included in the cluster, as shown in Fig. 2 (18) where, N i , n n pi and n n g denote the number of actual particles included in a cluster particle and the velocity vectors of the particle and the gas, respectively. Procedure of Simulation DEM-CFD Model for the Blast FurnaceA blast furnace of 5 000 m 3 inner volume with 40 tuyeres was taken as the object for present simulation. The profile of the blast furnace is shown in Fig. 3. In order to decrease number of particle in DEM, semicircle model which has a flat wall in front with no friction was employed. However, this model is based on the three dimensional structure.Raceways are represented by 20 spheres with 1.6 m in diameter which placed equally-spaced on wall at tuyere level. Particles of coke entrained in the raceway disappeared at arbitrarily-specified interval. The pig iron and slag layer in the hearth are not considered. The curved line which denotes melting zone was placed from 1.0 to 7.4 m over tuyere level as shown in Fig. 3, and particles of ore disappeared on the line. The top surface of burden descends with consumption of ore at melting zone and coke at raceways. When surface of burden places at 1 m below from stock line, coke and ore particles are charged alternately. Gas phase was assumed to be isothermal and incompressible.Motion of burden particles was calculated by the DEM and, then distribution of voidage was derived from position of particles. Depending on the voidage in blast furnace, gas flow was calculated by CFD. Gas drag force on particle in DEM was generated from gas flow. The details of the DEM-CFD model were described in the previous papers. 8) In this study, the method based on numeric strict technique (...

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confidence: 99%

Dynamic Analysis of Gas and Solid Flows in Blast Furnace with Shaft Gas Injection by Hybrid Model of DEM-CFD

et al. 2011

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“…The reducing gas for this process was produced by reforming COG or oil. [9][10][11] The effect of reducing gas injection was verified with an experimental blast furnace and in test operation with a commercial blast furnace. 9) After the 1980s, the oxygen blast furnace attracted special attention from the viewpoint of massive coal injection.…”

Section: Progress Of Blast Furnacementioning

confidence: 99%

“…[9][10][11] The effect of reducing gas injection was verified with an experimental blast furnace and in test operation with a commercial blast furnace. 9) After the 1980s, the oxygen blast furnace attracted special attention from the viewpoint of massive coal injection. [20][21][22][23] Conventional PCI surely makes it possible to replace coke with coal; however, the replacement ratio is restricted by the limited oxygen concentration in the hot blast.…”

Section: Progress Of Blast Furnacementioning

confidence: 99%

“…In parallel with the development of these combined blast furnace operation, provisional research on injection of reducing gas into the blast furnace shaft was also carried out. [7][8][9][10][11] In these processes, hot reducing gas is produced by partial oxidation and reforming of oil, natural gas or coke oven gas (COG), and is then injected into the lower shaft of the blast furnace in order to drastically decrease the coke rate through intensified gas reduction. Although these technologies were not commercialized for economic reasons, they nevertheless provided many significant results, later leading to the top gas recycling and oxygen blast furnace.…”

Section: Evolution Of Blast Furnace Process Toward Reductant Flexibilmentioning

confidence: 99%

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Evolution of Blast Furnace Process toward Reductant Flexibility and Carbon Dioxide Mitigation in Steel Works

Ariyama

Sato²,

Nouchi³

et al. 2016

ISIJ International

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“…Both Kobayashi et al and Miyashita et al concluded that the gas should contain less CO 2 and H 2 O and had to be heated above 1 000°C to satisfy the staged heat balance by both theoretical and experimental methods. 7,8) Stack gas injection was also applied to oxygen enriched BF and found to increase gaseous reduction in a relatively low temperature region and to decrease carbon solution loss reaction in order to save coke. [9][10][11][12][13] As far as the injection gas was concerned, Yatsuzuka et al developed Fuji-Texaco-Gas (FTG) injection process combining a partial oxidation process to produce it from the available fuel oil outside the furnace, 14,15) while Buchwalder et al developed Hot Gas Generators (HGG) to produce it from natural gas.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Pre-reduction Shaft Furnace with Top Gas Recycling Technology Aiming to Cut Down CO2 Emission

Yagi

et al. 2011

ISIJ Int.

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Top gas recycling is considered as one of the highest potential technologies to improve reduction efficiency and correspondingly to reduce carbon consumption. As a typical nitrogen free ironmaking process, pre-reduction shaft furnace of COREX ® process (COREX ® shaft furnace) for short is suitable to adopt the technology aiming to cut down CO2 emission. Under the premise of constant total injection volume, three kinds of reducing gas injection methods are numerically studied by employing a two-dimensional mathematical model. The method that 20% of total reducing gas in volume fraction is blasted through normal inlet (NI) while the rest through down pipe inlet (PI) rather than deadman inlet (DI) could apparently improve gas flow in the inactive zone located near the bottom direct reduced iron (DRI) outlet, thus increasing DRI reduction degree to 61% under present calculation conditions. Meanwhile, either decreasing the vertical height of PI or increasing its diameter makes further improvement on furnace efficiency. After adopting top gas recycling to the shaft furnace by NI+PI method with optimal parameters, CO utilization ratio reaches above 46% when DRI reduction degree correspondingly increases by 12%, what's more, CO2 emission from the whole process is reduced by about 540 Nm 3 /tHM. The results prove that top gas recycling technology promotes reduction efficiency inside shaft furnace and greatly reduces the greenhouse gas emission, which will contribute to suppressing global warming.

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Reducing Gas Injection into Furnace Stack in an Experimental Furnace

Cited by 17 publications

References 0 publications

Dynamic Analysis of Gas and Solid Flows in Blast Furnace with Shaft Gas Injection by Hybrid Model of DEM-CFD

Dynamic Analysis of Gas and Solid Flows in Blast Furnace with Shaft Gas Injection by Hybrid Model of DEM-CFD

Evolution of Blast Furnace Process toward Reductant Flexibility and Carbon Dioxide Mitigation in Steel Works

Prediction of Pre-reduction Shaft Furnace with Top Gas Recycling Technology Aiming to Cut Down CO2 Emission

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