Effect of Annealing on Properties of Carbonaceous Materials. Part II: Porosity and Pore Geometry

Xing, Xing; Zhang, Guangqing; Dell’Amico, Mark; Ciezki, George; Meng, Qingbo; Ostrovski, Oleg

doi:10.1007/s11663-013-9854-4

Cited by 23 publications

(17 citation statements)

References 15 publications

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“…On the other hand, Echterhoff 7) conducted the Micum test of coke at 1 323 K and observed a general deterioration in the coke strength when the temperature increased above the coking temperature. This phenomenon was also confirmed by Bradshaw et al 8) Patrick et al 11) observed a degradation of tensile strength of cokes when tested at 1 723 K. Xing et al 9,10) examined the effect of annealing of cokes, chars and pyrolysed coals in the temperature range of 973 to 1 773 K on tensile strength measured at room temperature. The tensile strength of chars and pyrolysed coals was strongly enhanced by annealing in the temperature range of 973-1 373 K. The tensile strength of cokes was slightly decreased by the heat treatment after the annealing temperature increased above 1 573 K. Coke degradation upon heating to temperatures close to the raceway flame temperature was not studied.…”

Section: Introductionmentioning

confidence: 60%

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Coke Degradation under Simulated Blast Furnace Conditions

Xing

Rogers²,

Zhang

et al. 2016

ISIJ Int.

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Three metallurgical cokes made from coking coals over a significant range in rank were subjected to treatment with blast furnace-like gas composition-temperature profile to 1 673 K, annealing under N 2 to 2 273 K and gasification with subsequent annealing at 1 873 and 2 273 K. The degradation of cokes after reaction and annealing was characterised using I-drum tumbling, tensile testing, ultra-micro indentation and X-ray diffraction. Both gasification and annealing decreased the mechanical strength of coke. Compared with annealing at 1 673 K, gasification at same temperature caused larger degradation for all three cokes, and the effect was more significant on more reactive coke. In the annealing process, degradation of the cokes occurred through the entire coke lump and resulted in both tensile strength and I-drum tumbling strength decreasing simultaneously. In the process of gasification under the blast furnace-like conditions, degradation took place through the whole piece of coke with high reactivity; however, the degradation of coke with low reactivity was more severe at the periphery than in the core and therefore gasification had a minimal effect on the core of the coke and its tensile strength, but had a much stronger effect on I * 600 . Microstrength of coke decreased significantly with increasing annealing temperature. The change of microstrength of coke upon gasification, which occurred at relatively low temperatures, was marginal. The cokes after gasification with subsequent annealing had similar microstrength and graphitisation degree compared to those subjected only to annealing at the same temperature.

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Section: Introductionmentioning

confidence: 60%

“…[6][7][8][9][10][11] Grant et al 6) found that the compressive strength of cokes at 1 673 K was higher than that at ambient temperature. On the other hand, Echterhoff 7) conducted the Micum test of coke at 1 323 K and observed a general deterioration in the coke strength when the temperature increased above the coking temperature.…”

Section: Introductionmentioning

confidence: 99%

Coke Degradation under Simulated Blast Furnace Conditions

Xing

Rogers²,

Zhang

et al. 2016

ISIJ Int.

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“…However, plots of weight change vs porosity increment for gasification and annealing are quite different, which can be attributed to the different mechanisms of porosity development. During gasification, the coke weight loss was mainly caused by the Boudouard reaction Besides the Boudouard reaction, the carbon-mineral reaction occurred below 1400 °C as well as the moisture and volatile matter release also contributed to the change of pore structure during gasification Figure presents micrographs of the bio-coke gasified to different stages.…”

Section: Resultsmentioning

confidence: 99%

“…After conversion, the pores and walls of the cokes were represented by black and white areas, respectively. The total porosity of cokes was calculated using ImageJ as the area fraction of the black area …”

Section: Methodsmentioning

confidence: 99%

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Pore Structure and Integrity of a Bio-Coke under Simulated Blast Furnace Conditions

Xing

2019

Energy Fuels

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Coke produced with 7.5 wt % charcoal addition and its base blend coke were subjected to gasification and annealing simulating the conditions within an iron-making blast furnace (BF). The changes in the pore structure of cokes during gasification and annealing were studied using image analysis to understand the effect of charcoal addition on pore structure development and degradation mechanism of coke under blast furnace operating conditions. The addition of charcoal had no significant effect on the coke pore structure during blast furnace annealing; the similar behaviors between cokes were mainly attributed to the carbon-mineral reactions that took place equivalently in both cokes. However, gasification in blast furnace caused a greater change in bio-coke pore structure, and this extra change in pore structure during gasification associated with charcoal addition was due to the preferential consumption of charcoal particles by the Boudouard reaction. Coke degradation under the BF conditions is directly related to the change in its pore structure and microstrength. Coke microstrength was not significantly impacted by charcoal addition; the greater degradation of bio-coke during BF gasification was due to the extra change in its pore structure.

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Effects of Temperature and Alkali Carbonates on Graphitization and Metallurgical Properties of Coke

Zhu

Zhang

Suo

et al. 2019

The Minerals, Metals &Amp; Materials Series

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Effect of Annealing on Properties of Carbonaceous Materials. Part II: Porosity and Pore Geometry

Abstract: The pore structure of carbonaceous materials was studied using image analysis. The effect of annealing on the porosity and pore geometry of cokes, chars, and pyrolyzed coals (laboratory chars) was examined in the temperature range of 973 K

Cited by 23 publications

References 15 publications

Coke Degradation under Simulated Blast Furnace Conditions

Coke Degradation under Simulated Blast Furnace Conditions

Pore Structure and Integrity of a Bio-Coke under Simulated Blast Furnace Conditions

Effects of Temperature and Alkali Carbonates on Graphitization and Metallurgical Properties of Coke

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