The effect of alkali on the reaction kinetics and strength of blast furnace coke

Dastidar, Maharshi Ghosh; Bhattacharyya, Anrin; Sarkar, Bikash Kumar; Dey, Rajib; Mitra, M.K.; Schenk, Johannes

doi:10.1016/j.fuel.2020.117388

Cited by 27 publications

(9 citation statements)

References 17 publications

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“…There are two primary sources of minerals that affect coke’s reactivity: the inherent minerals in the coke matrix and the extrinsic minerals that are enriched in the blast furnace. A large number of studies have pointed out that the minerals in the coke matrix showed different promotion effects on the reactivity of the coke [ 30 , 31 , 32 , 33 , 34 ]. Generally, the cations of the minerals played a critical role in the promotion effects.…”

Section: Relations Between Coke Structures and Propertiesmentioning

confidence: 99%

A Comprehensive Review of Characterization Methods for Metallurgical Coke Structures

Zheng

Zhang

et al. 2021

Materials

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The structure of coke affects its reactivity and strength, which directly influences its performance in the blast furnace. This review divides coke structures into chemical structure, physical structure, and optical texture according to their relevant characteristics. The focuses of this review are the current characterization methods and research status of the coke structures. The chemical structures (element composition and functional group) can be characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance imaging technology (13C NMR). The physical structures (pore structure and micro-crystallite structure) can be characterized by image method, X-ray CT imaging technique, mercury intrusion method, nitrogen gas adsorption method, X-ray diffraction method (XRD), and high-resolution transmission electron microscopy (HRTEM). The optical textures are usually divided and counted by a polarizing microscope. In the end, this review provides an idea of the construction of a coke molecular structural model, based on the above characterization. With the coke model, the evolution principles of the coke can be calculated and simulated. Hence, the coke performance can be predicted and optimized.

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Section: Relations Between Coke Structures and Propertiesmentioning

confidence: 99%

A Comprehensive Review of Characterization Methods for Metallurgical Coke Structures

Zheng

Zhang

et al. 2021

Materials

Self Cite

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“…The catalytic effect of alkali elements on coke graphitization has also been claimed in previous studies. 1,33,34 It should be noted that the coke got consumed by reacting with the alkali elements, and its particle size became smaller. The contact area with molten iron was increased and the catalysis of molten iron was promoted.…”

Section: Discussion and Analysismentioning

confidence: 99%

“…CO 2 emission and longevity of a blast furnace have been the topics of most concern for iron-making workers all over the world. , Coke is one of the important raw fuels of blast furnace iron-making. It takes a long time for coke to be renewed in the blast furnace hearth, so the accumulation of coke for a long time leads to the formation of deadman.…”

Section: Introductionmentioning

confidence: 99%

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

et al. 2021

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The graphitization and performance of deadman coke in the blast furnace hearth have an essential influence on the longevity of the blast furnace. In this paper, coke samples were obtained from various heights in a hearth during the overhaul of the blast furnace. The voidage, particle size, graphitization degree, microstructure, and structure evolution of multiple cokes were analyzed through digital image processing, XRD, Raman spectra, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (SEM-EDS). The graphitization results were compared with feed coke, tuyere coke, cohesive zone coke, and deadman coke in reference, and the main findings were analyzed. The following results were obtained. First, the voidage of deadman coke increased and then decreased with the increase of the depth while the particle size continued to decrease. In addition, the consumption rate of coke as a carburizer, reductant, and heart source was 8.47, 30.95, and 60.58%, respectively. Second, the graphitization degree of deadman coke was extremely high and showed a trend of first increasing and then decreasing. Finally, the evolution mechanism of coke graphitization was proposed. Molten iron, alkali metal, temperature, and mineral were the crucial factors that affect the graphitization of coke. The turning point of the graphitization degree was related to the buoyancy of the hearth.

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“…The reactivity of the four coke samples was more than 30% at four different temperature turning points. The results show that a decrease in coke strength was mainly caused by the destruction of coke skeleton structure due to the large amount of carbon loss [32]. When the carbon loss quantity of coke exceeds a certain range, the pore structure of coke is damaged; the structure becomes loose, and the cracks increase, ultimately leading to a decrease in the coke strength after the reaction.…”

Section: Thermal Performance Testmentioning

confidence: 97%

Indirect Drying and Coking Characteristics of Coking Coal with Soda Residue Additive

Zhang

2021

Energies

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To improve indirect drying efficiency, the effect of soda residue on the drying characteristics of coking coal were studied using a self-made indirect drying system. A tube furnace was used in the dry distillation of coal samples with soda residue, and the coke properties were analyzed. The results indicated that the soda residue has a significant influence on the increase in the heating rate of coal samples in the temperature distribution range of 90 to 110 °C. With the addition of 2%, 5%, and 10% soda residue, the drying rates increased by 11.5%, 25.3%, and 37.3%, respectively at 110 °C. The results of dry distillation show that addition of 2%, 5% and 10% soda residue decreases the carbon loss quantity by 4.67, 4.99, and 8.82 g, respectively. The mechanical strength of coke samples satisfies the industrial conditions when the soda residue ratio ranges from 2% to 5%. Soda residue can improve the active point of coke dissolution reaction and inhibit coke internal solution. Economically, coking coal samples mixed with soda residue have an obvious energy saving advantage in the drying process. Energy saving analysis found that it can reduce cost input by 20% than that of the normal drying method.

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The effect of alkali on the reaction kinetics and strength of blast furnace coke

Cited by 27 publications

References 17 publications

A Comprehensive Review of Characterization Methods for Metallurgical Coke Structures

A Comprehensive Review of Characterization Methods for Metallurgical Coke Structures

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

Indirect Drying and Coking Characteristics of Coking Coal with Soda Residue Additive

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