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

Abstract

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.

Modeling and Simulation of Metallurgical Processes in Ironmaking and Steelmaking

“…The authors employed the developed graphical tool for a sensitivity study of the reduction in the shaft furnace. Wang et al [4] present a combination of numerical and experimental investigations of the charging of carbon composite briquettes in a blast furnace. The authors studied the replacement of ore by the carbon composite briquettes and report on carbon conversion, coke rate, blast furnace operation, and productivity, etc.…”

A Numerical Study of Scenarios for the Substitution of Pulverized Coal Injection by Blast Furnace Gas Enriched by Hydrogen and Oxygen Aiming at a Reduction in CO2 Emissions in the Blast Furnace Process

“…These materials are introduced in the blast furnace as pulverized coal for injection (PCI) or granular coke that is supplied via the tuyeres of the furnace. In order to make the process more ecologically friendly, efforts have been made to decrease the reducing agent rate (RAR) or, at the very least, replacing the coke consumption of the blast furnace with alternative materials injected through the tuyere [10][11][12][13][14][15][16][17][18][19][20][21].…”

“…Unstable conditions are caused by the accumulation of unburned powder in the lower section of the blast furnace and the high viscosity slag produced during ash melt, both of which reduce the permeability of the dropping zone [18][19][20][21][22][23][24][25][26][27][28][29][30]. The temperature and gas flow inside the raceway are significantly altered when mixed gases are injected into the blast furnace.…”

Prediction of the Consumption of Raw Materials and Fuels for the Blast Furnace

“…The model simultaneously estimates the blast furnace process parameters. Qiang Wang, et al have proven that numerical simulations within the replacement carbon composite briquettes save coke [18]. The new directions of simulations and modelling focus on the degree of utilisation of blast furnace gas.…”