Coke graphitization and degradation across the tuyere regions in a blast furnace

Gupta, Sushil K.; Ye, ZhuoZhu; Kanniala, Riku; Kerkkonen, Olavi; Sahajwalla, Veena

doi:10.1016/j.fuel.2013.05.074

Cited by 93 publications

(57 citation statements)

References 10 publications

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“…The crystallite height of the carbons of deadman coke fines is larger and increases from 24.31 to 44.35 nm from DM1.8-F to DM > 5.0-F, which is about 5-10 times the value of the crystallite height of the feed coke. The average crystallite height of carbons of deadman coke lumps ranges from over 11 nm for DM1.8-L to about 16 nm for DM3.3-L which is much higher than that of the cokes (3-7 nm 19) ) at tuyere level and the feed coke (4.0 nm). It may relate to the contribution of prolonged hot metal contact, 20) prolonged final slag contact and high temperature treatments 19) on improving the ordering of carbon structure of coke.…”

Section: The Analysis Of the Carbon Structure Of The Deadman Cokesmentioning

confidence: 82%

“…The average crystallite height of carbons of deadman coke lumps ranges from over 11 nm for DM1.8-L to about 16 nm for DM3.3-L which is much higher than that of the cokes (3-7 nm 19) ) at tuyere level and the feed coke (4.0 nm). It may relate to the contribution of prolonged hot metal contact, 20) prolonged final slag contact and high temperature treatments 19) on improving the ordering of carbon structure of coke. The average interlayer spacing d 002 of deadman coke carbons ranges from 0.3386 nm to 0.3498 nm which is less than that of the feed coke (0.3607 nm).…”

Section: The Analysis Of the Carbon Structure Of The Deadman Cokesmentioning

confidence: 82%

“…This implies that the most ordered carbon structure occurs in deadman coke fines, followed by deadman coke lumps and the feed coke. Gupta 19) and Li 10) found that the graphitization of coke in the high temperature zone starts from the coke surface and the graphitization process leads to the formation of coke fines. The previous studies 21,22) proposed that the carbon in highly ordered coke would be easier to dissociate and this leads to higher dissolution rates.…”

Section: The Analysis Of the Carbon Structure Of The Deadman Cokesmentioning

confidence: 99%

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Changes in Microstructure and Chemical Composition of Deadman Coke of a 2800 m<sup>3</sup> Industrial Blast Furnace

Niu

Cheng

et al. 2018

ISIJ Int.

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The paper examined the changes in microstructure and inorganic elements in their true mineral forms of the coke samples from various hearth locations using X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) after the blow out and cool down of a 2 800 m 3 industrial blast furnace. The results illustrate that all deadman coke samples from fines to lumps were confirmed to be highly graphitized. Furthermore, the deadman coke was filled up with the accumulated KAlSiO 4 during its descent process and the blast furnace slag which consisted of Ca 2 MgSi 2 O 7 -Ca 2 Al 2 SiO 7 system and Ca 2 ZnSi 2 O 7 phases. Besides the slag phases, the iron was also observed in the deadman coke soaked in the iron layer. Those cause that the mass of the deadman coke is about 1.62-2.82 times larger than that of the feed coke under the same conditions. Thus it may make the deadman which was designed to float sit on the hearth bottom as the permeation of the slag and the liquid iron into the deadman coke was not taken into consideration during the design process. We concluded that the slag phase below the taphole level is primarily derived from the blast furnace slag. Moreover, the deadman coke carrying final slag may come in contact with the hearth bottom and react with ceramic pad or carbon brick with a sitting deadman, thereby it results in degrading the hearth lining. Meanwhile, the slag phases below the taphole level can provide the material for the formation of skull to protect the hearth lining.

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Section: The Analysis Of the Carbon Structure Of The Deadman Cokesmentioning

confidence: 82%

Section: The Analysis Of the Carbon Structure Of The Deadman Cokesmentioning

confidence: 82%

Section: The Analysis Of the Carbon Structure Of The Deadman Cokesmentioning

confidence: 99%

See 1 more Smart Citation

Changes in Microstructure and Chemical Composition of Deadman Coke of a 2800 m<sup>3</sup> Industrial Blast Furnace

Niu

Cheng

et al. 2018

ISIJ Int.

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“…1(b)) was used to estimate the tuyere level temperature profile following previous approach. 13,15,16) Figure 1(c) shows the temperature profile estimated on the basis of differences in Lc values of tuyere cokes. Raceway region has the highest temperature which was greater than 2 300°C.…”

Section: Resultsmentioning

confidence: 99%

SiC and Ferro-silicides Formation in Tuyere Cokes

Gupta

Kerkkonen

et al. 2013

ISIJ Int.

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“…XRD is a well-established technique to determine the microcrystalline structural parameters of carbonaceous materials with good reliability [25][26][27]. The proportion of crystalline carbon and amorphous carbon indicates the degree of ordering of the carbon, which can be investigated by the average stack height (Lc).…”

Section: Micro Crystalline Structure Of Carbonaceous Materials Of Samplesmentioning

confidence: 99%

Research on the Combustion Characteristics and Kinetic Analysis of the Recycling Dust for a COREX Furnace

et al. 2017

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Thermogravimetric analysis of recycling dust (RD) from the melter gasifier of COREX, coke1 (C-1), coke2 (C-2) and coal char (CC) under 70% oxygen atmosphere was carried out using thermal balance. The chemical composition and physical structure of the samples were investigated. The characteristic temperatures and comprehensive combustion characteristic indexes were calculated and kinetic parameters during the combustion process were calculated as well using a distributed activation energy model (DAEM). The results show that the carbon in the recycling dust originates from unconsumed CC and coke fines, and the average stacking height of carbon in RD is larger than that of C-1, C-2 and CC. The conversion curves of RD are different from those of C-1, C-2 and CC, and there are two peaks in the RD conversion rate curves. The combustion profiles of RD moves to a higher temperature zone with increasing heating rates. The average activation energies of their combustion process for RD, C-1, C-2 and CC range from 191.84 kJ/mol to 128.31 kJ/mol. The activation energy for recycling dust increases as the fractional conversion increases, but the value for C-1, C-2 and CC decreases with increasing conversion, indicating different combustion mechanisms.

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Coke graphitization and degradation across the tuyere regions in a blast furnace

Cited by 93 publications

References 10 publications

Changes in Microstructure and Chemical Composition of Deadman Coke of a 2800 m<sup>3</sup> Industrial Blast Furnace

Changes in Microstructure and Chemical Composition of Deadman Coke of a 2800 m<sup>3</sup> Industrial Blast Furnace

SiC and Ferro-silicides Formation in Tuyere Cokes

Research on the Combustion Characteristics and Kinetic Analysis of the Recycling Dust for a COREX Furnace

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