A review on nut coke utilisation in the ironmaking blast furnaces

Gavel, Dharm Jeet

doi:10.1080/02670836.2016.1183073

Cited by 25 publications

(15 citation statements)

References 42 publications

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“…Despite being beneficial in the iron making process, nut coke is utilised in limited quantity (less than 23 wt%). 5) It was also reported elsewhere that nut coke addition may bring a negative impact on the overall gas permeability due to the regular coke layer thinning. 1,14) Therefore, considering the idea of nut coke use as the replacement of regular coke, it is of utmost importance to understand its impact on the gas permeability, when regular coke layer is thinned due to the higher replacement ratios (more than 20 wt% of the regular coke).…”

Section: Introductionmentioning

confidence: 75%

“…[2][3][4] Furthermore, nut coke addition to the ferrous raw material has beneficial effects on enhancing the shaft permeability, lowering thermal reserve zone temperature and improving burden softening-melting properties. 5) Some studies were already performed to understand the influence of nut coke addition on the ferrous burden. For example, Babich et al 6) reported the improvement in the shaft permeability, and therefore the furnace productivity was enhanced (1.5% to 2.5%) with the nut coke mixing (10-20 wt%).…”

Section: Introductionmentioning

confidence: 99%

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Effect of Nut Coke Addition on Physicochemical Behaviour of Pellet Bed in Ironmaking Blast Furnace

et al. 2019

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One of the primary causes that limit the blast furnace productivity is the resistance exerted to the gas flow in the cohesive zone by the ferrous burden. Use of nut coke (10-40 mm) together with ferrous burden proves beneficial for decreasing this resistance. In present study, effect of nut coke addition on the olivine fluxed iron ore pellet bed is investigated under simulated blast furnace conditions. Nut coke mixing degree (replacement ratio of regular coke) was varied from 0 to 40 wt% to investigate the physicochemical characteristics of the pellet bed. Three distinct stages of bed contraction are observed and the principal phenomena governing these stages are indirect reduction, softening and melting. It is observed that nut coke mixing enhances the reduction kinetics, lowers softening, limits sintering and promotes iron carburisation to affects all three stages. In the second stage, the temperature and displacement range is reduced by 60°C and 24%, respectively upon 40 wt% nut coke mixing. Addition of nut coke exponentially increases the gas permeability (represented by pressure drop and S-value). A higher degree of carburisation achieved on the pellet shell (iron) is suggested to be the principal reason for decrease in the pellet melting temperature. The pellets softening temperature increases by approximately 4°C, melting and dripping temperature drops by 11°C and 12°C, respectively, for every 10 wt% nut coke addition. Consequently, the nut coke addition shortens the softening, melting and dripping temperature ranges, which shows improved properties of the cohesive zone.

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Section: Introductionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Effect of Nut Coke Addition on Physicochemical Behaviour of Pellet Bed in Ironmaking Blast Furnace

et al. 2019

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“…Figure 4b shows that the CCB carbon starts gasification at approximately 923 K. Above the CZ, its overall conversion is 85%, indicating that 15% of the CCB carbon would enter the BF lower part. In the present investigation, the influence of the ungasified CCB carbon in the BF lower part was not considered as its behavior has not been distinctly disclosed so far [37]. Figure 5 shows the behavior of a single CCB along a solid flowing path in the BF.…”

Section: Ccb Behavior In Bfmentioning

confidence: 98%

Experimental and Numerical Investigations on Charging Carbon Composite Briquettes in a Blast Furnace

Wang

Tang

et al. 2021

Metals

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In the present research, charging carbon composite briquettes (CCB) in a blast furnace (BF) was investigated. The CCB used contained 29.70 wt.% Fe3O4, 39.70 wt.%, FeO, 1.57 wt.% iron, 8.73 wt.% gangue, and 20.30 wt.% carbon. Its reaction kinetics in BF was examined by nonisothermal tests and modeled. Thereafter, the influence of replacing 10% ore with CCB on BF performance was studied by numerical simulations. Results showed that the CCB reaction behavior in BF could be modeled using the previously proposed model under ags = 1900 m2·m−3. Numerical simulations on a BF with a production of 6250t hot metal per day (tHM/day) showed that replacing 10% ore with CCB efficiently improved the BF operation for coke saving. In the CCB charging operation, the CCB reached a full iron-oxide reduction above the cohesive zone (CZ) and a carbon conversion of 85%. By charging CCB, the thermal state in the BF upper part was significantly changed while it was not influenced in the BF lower part; the ore reduction was retarded before the temperature reached 1073 K and was prompted after and the local gas utilization tends to increase above the CZ. By the CCB reduction above the CZ, BF top gas temperature was decreased by 8 K, the BF top gas utilization was increased by 1.3%, the BF productivity was decreased by 17 tHM/day, the coke rate was decreased by 52.2 kg/tHM, and ore rate was decreased by 101 kg/tHM. Considering the energy consumption of sintering and coking, charging the CCB could have a significant energy-saving and CO2-emission-reducing effect for BF iron making.

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“…An over amount of ungasified carbon particles in BCB may cause clogging, leading to an abnormal BF operation. 41) From Figs. 12(d)-12(e), it is estimated that the average residual carbon content is 0.0 wt.% in case A, 2.2 wt.% in case B, and 3.9 wt.% in case C. Furthermore, the BCB charged near the BF wall would have a carbon content higher than the average value (Fig.…”

Section: Optimzing Bcb Charging Operationmentioning

confidence: 99%

Numerical Simulation of Charging Biochar Composite Briquette to Blast Furnace

2022

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Partial replacement of coal and coke by biomass/biochar in the blast furnace (BF) ironmaking is important role to reduce CO 2 emissions. In this research, numerical investigations were conducted on blast furnace (BF) operation with biochar composite briquette (BCB) charging. The BCB was with 11.1 mass% carbon, 72.7 mass% magnetite, 11.25 mass% wustite, 0.77 mass% metallic iron, and 4.67 mass% gangue, and the BCB charging ratio was from 0 to 60% Results revealed that in the BF operation with BCB charging, the BCB iron-oxide reached a full reduction, but the overall gasification degree of BCB biochar decreased with the increase of BCB charging ratio. By charging BCB, the thermal state in the upper BF was considerably altered, but it was insignificantly influenced in the lower BF. By charging BCB; ore reduction was retarded in the upper BF but was prompted near the zone with a temperature of 1 173 K. Under a low BCB charging ratio, local gas utilization tended to increase in the mid BF but tended to decrease in the upper BF. Further increasing BCB charging ratio lead to a decrease in local gas utilization. To ensure BF smooth running and maximizing biochar input, the optimal BCB charging ratio was 40%. Under this condition, the BCB biochar of 89.3 kg/tHM could be completely utilized, and the BF coke rate was decreased by 92.1 kg/tHM.

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A review on nut coke utilisation in the ironmaking blast furnaces

Cited by 25 publications

References 42 publications

Effect of Nut Coke Addition on Physicochemical Behaviour of Pellet Bed in Ironmaking Blast Furnace

Effect of Nut Coke Addition on Physicochemical Behaviour of Pellet Bed in Ironmaking Blast Furnace

Experimental and Numerical Investigations on Charging Carbon Composite Briquettes in a Blast Furnace

Numerical Simulation of Charging Biochar Composite Briquette to Blast Furnace

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