The direct reduction process can reduce carbon emissions by over 50%compared to traditional blast furnace ironmaking.Carbon deposition and carburization are critical for ensuring process stability and economic viabili...The direct reduction process can reduce carbon emissions by over 50%compared to traditional blast furnace ironmaking.Carbon deposition and carburization are critical for ensuring process stability and economic viability.Thermodynamic phase diagrams were developed to intuitively represent carbon deposition and carburization preferences in CH4-CO-H_(2) ternary atmospheres.High carbon potential and low oxygen potential significantly enhance carbon deposition and carburization.Increasing temperature from 500 to 1000℃ shifts the dominant reactions from CO-based to CH_(4)-based,increasing maximum carbon deposition from 0.55 to 0.80 mol and carburization from 0.25 to 0.80 mol per mole of reducing gas.Increasing pressure suppresses CH4-based reactions while promoting CO-based reactions,reducing maximum carbon deposition from 0.8 to~0.7 mol and increasing maximum carburization from 0.80 to 0.85 mol per mole of reducing gas.Equilibrium phase diagrams for various carbides were also developed,revealing preferences for Fe_(3)C_(2),Fe_(7)C_(3),Fe_(5)C_(2),and Fe_(3)C as the Fe/C ratio increases.Higher temperatures and CH_(4) concentrations favor the formation of carbides with higher carbon content.Carburization preferences under typical Energiron ZR and Midrex atmospheres were highlighted,and the higher carbon content in direct reduction iron produced by the Energiron ZR process was thermodynamically confirmed.展开更多
Hydrogen displays the potential to partially replace pulverized coal injection(PCI)in the blast furnace,and it can reduce CO_(2)emissions.In this paper,a three-dimensional mathematical model of hydrogen and pulverized...Hydrogen displays the potential to partially replace pulverized coal injection(PCI)in the blast furnace,and it can reduce CO_(2)emissions.In this paper,a three-dimensional mathematical model of hydrogen and pulverized coal co-injection in blast furnace tuyere was established through numerical simulation,and the effect of hydrogen injection and oxygen enrichment interaction on pulverized coal combustion and raceway smelting was investigated.The simulation results indicate that when the coal injection rate decreased from 36 to 30t/h and the hydrogen injection increased from 0 to 3600 m^(3)/h,the CO_(2)emissions decreased from 1860 to 1551 kg/t,which represents a16.6%reduction,and the pulverized coal burnout decreased from 70.1%to 63.7%.The heat released from hydrogen combustion can not only promote the volatilization of pulverized coal but also affect the combustion reaction between volatilization and oxygen,which resulted in a decrease in the temperature at the end of the raceway.Co-injection of hydrogen with PCI increased the wall temperature near the upper half part of the raceway and at the outlet of the tuyere,which required a high cooling efficiency to extend the service life of the blast furnace.The increase in oxygen level compensated for the decreased average temperature in the raceway due to hydrogen injection.The increase in the oxygen content by 3%while maintaining constant hydrogen and PCI injection rates increased the burnout and average raceway temperature by 4.2%and 43 K,respectively.The mole fraction of CO and H_(2) production increased by 0.04 and 0.02,respectively.Burnout can be improved through optimization of the particle size distribution of pulverized coal.展开更多
Eggshells,a by-product of the food industry,represent a significant yet often overlooked waste stream.Given their vast production volume and inherent properties,eggshells have the potential to serve as a sustainable a...Eggshells,a by-product of the food industry,represent a significant yet often overlooked waste stream.Given their vast production volume and inherent properties,eggshells have the potential to serve as a sustainable and environmentally friendly co-fuel.Aiming to explore the co-combustion characteristics and kinetics of pulverized coal blended with eggshells and offer insights into their combined use as a renewable energy source,a systematic investigation was conducted to evaluate the physical and chemical properties of Shangwan bituminous coal,Shouyang anthracite coal,eggshell(ES)and their blends.Additionally,comprehensive experimental analyses were performed at different heating rates applying a non-isothermal thermogravimetric method.The findings revealed that the addition of ES enhanced the combustion efficiency.The combustion characteristics were significantly influenced by the ES content,with an optimal blend ratio identified for maximum combustion efficiency.To represent the thermal degradation experiments,random pore model and volume model were employed.Furthermore,activation energies and pre-exponential factors were determined.The random pore model demonstrated more superior performance compared to the volume model.The activation energies of all the samples ranged between 18.29 and 42.48 kJ/mol,with the lowest value observed for the sample containing 20 mass%ES.展开更多
Hydrogen-enriched blast furnace ironmaking has become an essential route to reduce CO_(2)emissions in the ironmaking process.However,hydrogen-enriched reduction produces large amounts of H_(2)O,which places new demand...Hydrogen-enriched blast furnace ironmaking has become an essential route to reduce CO_(2)emissions in the ironmaking process.However,hydrogen-enriched reduction produces large amounts of H_(2)O,which places new demands on coke quality in a blast furnace.In a hydrogen-rich blast furnace,the presence of H_(2)O promotes the solution loss reaction.This result improves the reactivity of coke,which is 20%-30%higher in a pure H_(2)O atmosphere than in a pure CO_(2)atmosphere.The activation energy range is 110-300 kJ/mol between coke and CO_(2)and 80-170 kJ/mol between coke and H_(2)O.CO_(2)and H_(2)O are shown to have different effects on coke degradation mechanisms.This review provides a comprehensive overview of the effect of H_(2)O on the structure and properties of coke.By exploring the interactions between H_(2)O and coke,several unresolved issues in the field requiring further research were identified.This review aims to provide valuable insights into coke behavior in hydrogen-rich environments and promote the further development of hydrogen-rich blast furnace ironmaking processes.展开更多
The limited understanding of the microstructure and dynamic evolution associated with the nonstoichiometric characteristics of wustite has constrained the comprehension of iron oxide properties,diffusion,and phase tra...The limited understanding of the microstructure and dynamic evolution associated with the nonstoichiometric characteristics of wustite has constrained the comprehension of iron oxide properties,diffusion,and phase transformation behaviors.This study employs deep learning methods to train interatomic potential parameters for the Fe–O system,achieving precise atomic-scale simulations of the wustite phase structure and internal lattice defects.This approach addresses the shortcomings of large-scale molecular dynamics simulations in accurately describing the solid-phase structure of the Fe–O system.Utilizing these potential parameters,this research is the first to reveal the complex mechanisms underlying the non-stoichiometric nature of wustite(Fe_(1−x)O).The study found that cation vacancy defects in wustite tend to aggregate,forming stable cluster structures.It also elucidated the formation mechanisms of interstitial iron atoms and typical defect clusters in wustite,establishing the formation preference for Koch–Cohen defect clusters.These potential parameters and research methods can be further applied in future studies on iron oxide reduction,phase transformation mechanisms,and related material development,thereby advancing fundamental research in metallurgy and related industries.展开更多
基金the financial support from the National Key R&D Program of China(No.2024YFC2910800)National Natural Science Foundation of China(52404336)+6 种基金China Postdoctoral Science Foundation(2024M750176)Postdoctoral Fellowship Program of CPSF(GZC20240109)the Young Elite Scientist Sponsorship Program by CAST(YESS20210090)Beijing Natural Science Foundation(J210017)the Project of SKLAM(No.KF24-14)China Baowu Low Carbon Metallurgical Technology Innovation Fund under Grant No.20210901Anhui Major Industrial Innovation Program under Contract No.AHZDCYCX-LSDT2023-01.
文摘The direct reduction process can reduce carbon emissions by over 50%compared to traditional blast furnace ironmaking.Carbon deposition and carburization are critical for ensuring process stability and economic viability.Thermodynamic phase diagrams were developed to intuitively represent carbon deposition and carburization preferences in CH4-CO-H_(2) ternary atmospheres.High carbon potential and low oxygen potential significantly enhance carbon deposition and carburization.Increasing temperature from 500 to 1000℃ shifts the dominant reactions from CO-based to CH_(4)-based,increasing maximum carbon deposition from 0.55 to 0.80 mol and carburization from 0.25 to 0.80 mol per mole of reducing gas.Increasing pressure suppresses CH4-based reactions while promoting CO-based reactions,reducing maximum carbon deposition from 0.8 to~0.7 mol and increasing maximum carburization from 0.80 to 0.85 mol per mole of reducing gas.Equilibrium phase diagrams for various carbides were also developed,revealing preferences for Fe_(3)C_(2),Fe_(7)C_(3),Fe_(5)C_(2),and Fe_(3)C as the Fe/C ratio increases.Higher temperatures and CH_(4) concentrations favor the formation of carbides with higher carbon content.Carburization preferences under typical Energiron ZR and Midrex atmospheres were highlighted,and the higher carbon content in direct reduction iron produced by the Energiron ZR process was thermodynamically confirmed.
基金financially supported by the National Natural Science Foundation of China(No.51904026)the Fundamental Research Funds for the Central Universities(No.06500108)。
文摘Hydrogen displays the potential to partially replace pulverized coal injection(PCI)in the blast furnace,and it can reduce CO_(2)emissions.In this paper,a three-dimensional mathematical model of hydrogen and pulverized coal co-injection in blast furnace tuyere was established through numerical simulation,and the effect of hydrogen injection and oxygen enrichment interaction on pulverized coal combustion and raceway smelting was investigated.The simulation results indicate that when the coal injection rate decreased from 36 to 30t/h and the hydrogen injection increased from 0 to 3600 m^(3)/h,the CO_(2)emissions decreased from 1860 to 1551 kg/t,which represents a16.6%reduction,and the pulverized coal burnout decreased from 70.1%to 63.7%.The heat released from hydrogen combustion can not only promote the volatilization of pulverized coal but also affect the combustion reaction between volatilization and oxygen,which resulted in a decrease in the temperature at the end of the raceway.Co-injection of hydrogen with PCI increased the wall temperature near the upper half part of the raceway and at the outlet of the tuyere,which required a high cooling efficiency to extend the service life of the blast furnace.The increase in oxygen level compensated for the decreased average temperature in the raceway due to hydrogen injection.The increase in the oxygen content by 3%while maintaining constant hydrogen and PCI injection rates increased the burnout and average raceway temperature by 4.2%and 43 K,respectively.The mole fraction of CO and H_(2) production increased by 0.04 and 0.02,respectively.Burnout can be improved through optimization of the particle size distribution of pulverized coal.
基金sponsored by the Major Science and Technology Special Plan“Unveiling and Leading”Project of Shanxi Province(No.202201050201011)Major Science and Technology Projects of Anhui Province(No.202210700037)Special Funding for Science and Technology of China Minmetals Corporation(No.2021ZXD01).
文摘Eggshells,a by-product of the food industry,represent a significant yet often overlooked waste stream.Given their vast production volume and inherent properties,eggshells have the potential to serve as a sustainable and environmentally friendly co-fuel.Aiming to explore the co-combustion characteristics and kinetics of pulverized coal blended with eggshells and offer insights into their combined use as a renewable energy source,a systematic investigation was conducted to evaluate the physical and chemical properties of Shangwan bituminous coal,Shouyang anthracite coal,eggshell(ES)and their blends.Additionally,comprehensive experimental analyses were performed at different heating rates applying a non-isothermal thermogravimetric method.The findings revealed that the addition of ES enhanced the combustion efficiency.The combustion characteristics were significantly influenced by the ES content,with an optimal blend ratio identified for maximum combustion efficiency.To represent the thermal degradation experiments,random pore model and volume model were employed.Furthermore,activation energies and pre-exponential factors were determined.The random pore model demonstrated more superior performance compared to the volume model.The activation energies of all the samples ranged between 18.29 and 42.48 kJ/mol,with the lowest value observed for the sample containing 20 mass%ES.
基金financially supported by the Young Elite Scientist Sponsorship Program by CAST(No.YESS20210090)the National Natural Science Foundation of China(No.51974019),Beijing Natural Science Foundation(J210017)China Baowu Low Carbon Metallurgy Innovation Foundation(Nos.BWLCF202119 and BWLCF 202117)。
文摘Hydrogen-enriched blast furnace ironmaking has become an essential route to reduce CO_(2)emissions in the ironmaking process.However,hydrogen-enriched reduction produces large amounts of H_(2)O,which places new demands on coke quality in a blast furnace.In a hydrogen-rich blast furnace,the presence of H_(2)O promotes the solution loss reaction.This result improves the reactivity of coke,which is 20%-30%higher in a pure H_(2)O atmosphere than in a pure CO_(2)atmosphere.The activation energy range is 110-300 kJ/mol between coke and CO_(2)and 80-170 kJ/mol between coke and H_(2)O.CO_(2)and H_(2)O are shown to have different effects on coke degradation mechanisms.This review provides a comprehensive overview of the effect of H_(2)O on the structure and properties of coke.By exploring the interactions between H_(2)O and coke,several unresolved issues in the field requiring further research were identified.This review aims to provide valuable insights into coke behavior in hydrogen-rich environments and promote the further development of hydrogen-rich blast furnace ironmaking processes.
基金the support of the Young Elite Scientist Sponsorship Program by CAST(YESS20210090)Beijing Natural Science Foundation(J210017)China Baowu Low Carbon Metallurgy Innovation Foundation-BWLCF202119.
文摘The limited understanding of the microstructure and dynamic evolution associated with the nonstoichiometric characteristics of wustite has constrained the comprehension of iron oxide properties,diffusion,and phase transformation behaviors.This study employs deep learning methods to train interatomic potential parameters for the Fe–O system,achieving precise atomic-scale simulations of the wustite phase structure and internal lattice defects.This approach addresses the shortcomings of large-scale molecular dynamics simulations in accurately describing the solid-phase structure of the Fe–O system.Utilizing these potential parameters,this research is the first to reveal the complex mechanisms underlying the non-stoichiometric nature of wustite(Fe_(1−x)O).The study found that cation vacancy defects in wustite tend to aggregate,forming stable cluster structures.It also elucidated the formation mechanisms of interstitial iron atoms and typical defect clusters in wustite,establishing the formation preference for Koch–Cohen defect clusters.These potential parameters and research methods can be further applied in future studies on iron oxide reduction,phase transformation mechanisms,and related material development,thereby advancing fundamental research in metallurgy and related industries.
