Numerical Investigation of Applying High-carbon Metallic Briquette in Blast Furnace Ironmaking

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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.

Section: Description Of Bf Operation With Ccb Chargingmentioning

confidence: 99%

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

Wang

Tang

et al. 2021

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“…Numerical simulations can offer the scholars very detailed information to examine their feasibility, understand their mechanisms, and optimize their parameters [16][17][18]. A computational fluid dynamic (CFD) model based on a full-scale BF was developed by the current authors previously [19]. The model is two-dimensional, axisymmetric, and steady.…”

Section: Model Developmentmentioning

confidence: 99%

“…The model is modified to accommodate the BF operation with scrap charging. Definitions or values of most variables in the model are detailed in [19].…”

Section: Model Developmentmentioning

confidence: 99%

Numerical Investigation of Blast Furnace Operation with Scrap Charging

She

et al. 2020

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One approach to reduce CO2 emission in the steelmaking industry is to recycle scrap to the blast furnace/basic oxygen furnace (BF/BOF) production system. This paper performed a numerical investigation on the BF operation with scrap charging. The investigated BF was with an inner volume of 820 m3, producing 2950 tons of hot metal per day (tHM/d). The simulated results indicated the following: Extra scrap addition in BF causes the decrease of shaft temperature, the decrease of local gas utilization, and the lowering of cohesive zone position, leading to an unstable BF running. The partial replacement of sinter with scrap in BF can mitigate the negative effects induced by scrap charging. The optimal scrap rate in the BF is 178 kg/tHM, under which the BF reaches a productivity of 3310 tHM/d, a top-gas utilization of 48.5%, and a top-gas temperature of 445 K. Compared to the base case, in the BF operation with scrap charging, the BF productivity is increased by 360 kg/tHM, its pulverized-coal rate and coke rate are decreased by 16.3 kg/tHM and 39.8 kg/tHM, respectively.

“…The actual BF environment was obtained from the simulation results [34] of a BF of 2500 m 3 with a productivity of 6250 ton hot-metal per day. CCB reaction behavior along a burden flowing path near the BF mid-radial zone was investigated (Figure 8a).…”

Section: Simulation Of Ccb Reaction Behavior In Actual Bfmentioning

confidence: 99%

Experimental and Numerical Investigation of Reaction Behavior of Carbon Composite Briquette in Blast Furnace

Tang

Sun

2019

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The application of carbon composite briquette (CCB) is considered to be an efficient method for achieving low-energy and low-CO2-emission blast furnace (BF) operations. In this research, a combined experimental and numerical study was conducted on the CCB reaction behavior in BF. The CCB used in this study had a composition of 20.10 wt.% carbon, 29.70 wt.% magnetite, 39.70 wt.% wüstite, and 1.57 wt.% metallic iron. Using the prepared CCB samples, isotherm reduction tests under a simulated BF atmosphere (CO-CO2-N2) were conducted and a reaction model was developed. Subsequently, the reaction behavior of CCB along the mid-radial solid descending path in an actual BF of 2500 m3 was analyzed by numerical simulations based on the experimental findings and the previous results of comprehensive BF modeling. The results of the experiments showed that the CCB model predictions agreed well with the experimental measurements. With respect to the BF, the results of the numerical simulations indicated that, along the path, before the CCB temperature reached 1000 K, the CCB was reduced by CO in the BF gas; when its temperature was in the range from 1000 to 1130 K, it underwent self-reduction and contributed both CO and CO2 to the BF gas; when its temperature was above 1130 K, it only presented carbon gasification. Moreover, these results also revealed that the reduction of iron oxide and the gasification of carbon inside the CCB proceeded under an uneven mode. The uneven radial distribution of the local reduction fraction and local carbon conversion were evident in the self-reducing stage of the CCB.