A technical review on coke rate and quality in low-carbon blast furnace ironmaking. (15th March 2023)

• Record Type: Journal Article
• Authors: Rahmatmand, Behnaz; Tahmasebi, Arash; Lomas, Hannah; Honeyands, Tom; Koshy, Pramod; Hockings, Kim; Jayasekara, Apsara
• Is Part Of: Fuel. Volume 336(2023)
• Publication Date: 2023-03-15
• Subjects: AAEM alkaline earth metal -- AFT adiabatic flame temperature -- ARA auxiliary reducing agent -- Bb bio-briquette -- Bc bio-coke -- BF blast furnace -- BOF basic oxygen furnace -- CC charcoal -- CCUS CO2 capturing utilization and storage -- CCS CO2 capture and storage (CCS) -- COG coke oven gas -- CR coke rate -- CRI coke reactivity index -- CSR coke strength after reaction -- DI drum strength -- DRI direct reduced iron -- E comprehensive energy consumption -- EAF electric arc furnace -- Eta efficiency of gas -- FOBF full oxygen blast furnace -- GHG greenhouse gas -- GM grain model -- H2R hydrogen rate -- HM hot metal -- HPC high performance caking additive -- HRG hot reducing gas -- IEA International Energy Agency -- IPCC Intergovernmental Panel on Climate Change -- ISM integrated steel mill -- M40 mechanical resistance index of coke -- Mtoe million tons of oil equivalent -- NG natural gas -- O/C iron ore to carbon ratio -- PC pulverized coal -- PCI pulverized coal injection -- PSA pressure swing adsorption -- PU polyurethane -- Ri iron ore reduction -- RC coke weight loss rate -- RAFT raceway adiabatic flame temperature -- RAR reducing agent ratio -- RCOG reformed coke oven gas -- RI180 reduction index of iron ore -- RPM random pore model -- SEC specific energy consumption -- SLR solution loss ratio -- TF torrefied food residue -- TFe qualified iron grade -- TFT theoretical flame temperature -- TGA thermogravimetric analysis -- TGR-OBF top gas recycling oxygen blast furnace -- TSD torrefied sawdust -- TWM1 torrefied wood -- VM volumetric model -- X mass% -- ϑinj hydrogen injection temperature -- φ gas content; Blast furnace ironmaking -- Metallurgical coke -- Hydrogen reduction -- GHG emissions -- Biomass -- Sustainability; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.127077
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Measures for reducing the carbon intensity of blast furnace ironmaking were introduced. Influences of low-carbon ironmaking processes on fuel requirements are reviewed. The introduction of alternative reductants cannot eliminate the need for metallurgical coke. Sustainability of blast furnace ironmaking depends on improving the H/C replacement ratio. Introduction of hydrogen promotes the solution loss and structural degradation of coke. Abstract: The blast furnace technology is still the main ironmaking route with a current global share of 70%. Reduction of fossil carbon consumption and CO2 emissions in blast furnace operations are essential for the decarbonization of steelmaking. Potential solutions such as introducing renewable carbon-based materials (torrefied biomass, charcoal), using hydrogen-enriched reducing gases (i.e., hydrogen gas, coke oven gas, reformed coke oven gas, green methane), oxygen enrichment with top gas recycling, and carbon capture and storage/utilization have been considered to decrease emissions. The enhanced sustainability of blast furnace operations depends primarily on improving the hydrogen-to-carbon replacement ratio. Hydrogen is an effective reducing agent, producing steam during the reduction of ferrous burden. The replacement of coke and PCI with hydrogen leads to reduced fuel rates and CO2 emissions. Although implementing the innovative ironmaking solutions reduces coke and coal consumption, coke cannot be replaced entirely as it plays an irreplaceable role as a mechanical support network and the permeable layer for gas movement in the blast furnace. The injection of alternative reducing agents into the blast furnace alters the reaction environment by changing gas composition and temperature. Therefore, understanding the impacts of new reaction conditions on coke rate and quality requirements is important to both coal producers and steel manufacturers. This paper reviews the current understanding of how the introduction of alternative reducing agents into the blast furnace influences the gasification behavior, degradation mechanism, and consumption rate of coke. The review also identifies the knowledge gaps and future research opportunities in the field.