In order to achieve ultra-low emissions of SO_(2)and NO_(x),the oxygen blast furnace with sintering flue gas injection is presented as a promising novel process.The CO_(2)emission was examined,and a cost analysis of t...In order to achieve ultra-low emissions of SO_(2)and NO_(x),the oxygen blast furnace with sintering flue gas injection is presented as a promising novel process.The CO_(2)emission was examined,and a cost analysis of the process was conducted.The results show that in the cases when the top gas is not circulated(Cases 1–3),and the volume of injected sintering flue gas per ton of hot metal is below about 1250 m^(3),the total CO_(2)emissions decrease first and then increase as the oxygen content of the blast increases.When the volume of injected sintering flue gas per ton of hot metal exceeds approximately 1250 m^(3),the total CO_(2)emissions gradually decrease.When the recirculating top gas and the vacuum pressure swing adsorption are considered,the benefits of recovered gas can make the ironmaking cost close to or even lower than that of the ordinary blast furnace.Furthermore,the implementation of this approach leads to a substantial reduction in total CO_(2)emissions,with reductions of 69.13%(Case 4),70.60%(Case 5),and 71.07%(Case 6),respectively.By integrating previous research and current findings,the reasonable oxygen blast furnace with sintering flue gas injection can not only realize desulfurization and denitrification,but also achieve the goal of reducing CO_(2)emissions and ironmaking cost.展开更多
The development of low-carbon cementitious materials involves the selection of the appropriate raw materials and the transformation of the hydration mechanism.In this study,low-carbon and low-cost cementitious materia...The development of low-carbon cementitious materials involves the selection of the appropriate raw materials and the transformation of the hydration mechanism.In this study,low-carbon and low-cost cementitious materials were prepared using municipal solid waste incineration fly ash(MSWI FA),blast furnace slag(BFS),and desulfurization gypsum(DFG)as raw materials to reduce clinker usage.Results showed that the compressive strength of K5(mass ratio of BFS:DFG:MSWI FA=7:1:2)after 360 d of curing was 41.49 MPa,with a low leaching concentration of heavy metal residues that meet groundwater Class II standards,a dioxin content of only 25 ngTEG/kg,and a stable pH value ranging between 11 and 11.5.Microscopic analysis revealed a continuous decrease in the Ca/Si atomic ratios of K4(mass ratio of BFS:DFG:MSWI FA:P-I 42.5=42:10:20:28)and K5,i.e.,1.18-1.54 and 1.04-1.23,respectively,with the increase in the hydration age.The highest Al/Si atomic ratio of K5,i.e.,0.26-0.31,was observed with the strongest conversion trend of calcium-silicate-hydrate gel into calcium-aluminum-silicate-hydrate gel,and the network structure of sodium-(calcium)-aluminum-silicate-hydrate gel zeolite-like phase was generated.The water-to-binder(WTB)mass ratio of 0.35 was determined to be more suitable for the K4 and K5 systems and resulted in a 56.83%and 90.82%reduction in half-life ta compared with the WTB ratio of o.5,respectively.Notably,the value of the reaction velocity constant K in the induction period was 10 times that of K1,and the autocatalytic reaction controlled the value of N to<1.The X-ray absorption near-edge structure indicated that Zn solidification produced Zn_(2)SiO_(4) with a small solubility product.The production of 1 t of K5 emitted only 10.83 kg/t of CO_(2),which was 40 times less than that of K1.Overall,K5 provides the highest economic benefit at 40.08 USD/t,and the clinker-free cementitious system with multisolid waste synergy has significant advantages in terms of solidifying harmful substances,reducing carbon emissions,and lowering costs.展开更多
Reducing CO_(2)emissions of the iron and steel industry,a typical heavy CO_(2)-emitting sector is the only way that must be passed to achieve the‘dual-carbon’goal,especially in China.In previous studies,however,it i...Reducing CO_(2)emissions of the iron and steel industry,a typical heavy CO_(2)-emitting sector is the only way that must be passed to achieve the‘dual-carbon’goal,especially in China.In previous studies,however,it is still unknown what is the difference between blast furnace basic oxygen furnace(BF-BOF),scrap-electric furnace(scrap-EF)and hydrogen metallurgy process.The quantitative research on the key factors affecting CO_(2)emissions is insufficient There is also a lack of research on the prediction of CO_(2)emissions by adjusting industria structure.Based on material flow analysis,this study establishes carbon flow diagrams o three processes,and then analyze the key factors affecting CO_(2)emissions.CO_(2)emissions of the iron and steel industry in the future is predicted by adjusting industrial structure The results show that:(1)The CO_(2)emissions of BF-BOF,scrap-EF and hydrogen metallurgy process in a site are 1417.26,542.93 and 1166.52 kg,respectively.(2)By increasing pellet ratio in blast furnace,scrap ratio in electric furnace,etc.,can effectively reduce CO_(2)emissions(3)Reducing the crude steel output is the most effective CO_(2)reduction measure.There is still 5.15×10^(8)-6.17×10^(8) tons of CO_(2)that needs to be reduced by additional measures.展开更多
The possibility of using hydrogen to lower CO 2 emissions in the iron-making process was confirmed by the heat and mass balances in the blast furnace operation. The mass and heat balances for hydrogen utilization in t...The possibility of using hydrogen to lower CO 2 emissions in the iron-making process was confirmed by the heat and mass balances in the blast furnace operation. The mass and heat balances for hydrogen utilization in the blast furnace were estimated by using the basic concept of RIST operating diagram. In this study, the RIST operating diagram was modified to be suitable for representing the operation with respect to hydrogen, where the RIST operating diagram is a graphical representation of heat and mass balance in blast furnace operation. RIST operating diagram was applied here to some individual parameters of interest such as H 2 injection in blast furnace process to reduce coke (carbon consumption). It was observed that the point W moved to the right in the RIST operating diagram under the condition of increasing hydrogen injection at tuyere, which originates from the contribution of gas composition (O/H 2 ) equilibrated with Fe/FeO at a certain temperature. Point P also moved downward due to heat requirement with respect to hydrogen utilization, by which the new RIST operating diagram for hydrogen utilization was able to be constructed. Under the condition of hydrogen injection, the expected overall carbon consumption in the blast furnace decreased due to the contribution of hydrogen.展开更多
基金the financial supports from Hubei Provincial Key Technologies Research and Development Program(2022BCA058)China Scholarship Council(201908420169)the European Project“Towards Fossil-free Steel”.
文摘In order to achieve ultra-low emissions of SO_(2)and NO_(x),the oxygen blast furnace with sintering flue gas injection is presented as a promising novel process.The CO_(2)emission was examined,and a cost analysis of the process was conducted.The results show that in the cases when the top gas is not circulated(Cases 1–3),and the volume of injected sintering flue gas per ton of hot metal is below about 1250 m^(3),the total CO_(2)emissions decrease first and then increase as the oxygen content of the blast increases.When the volume of injected sintering flue gas per ton of hot metal exceeds approximately 1250 m^(3),the total CO_(2)emissions gradually decrease.When the recirculating top gas and the vacuum pressure swing adsorption are considered,the benefits of recovered gas can make the ironmaking cost close to or even lower than that of the ordinary blast furnace.Furthermore,the implementation of this approach leads to a substantial reduction in total CO_(2)emissions,with reductions of 69.13%(Case 4),70.60%(Case 5),and 71.07%(Case 6),respectively.By integrating previous research and current findings,the reasonable oxygen blast furnace with sintering flue gas injection can not only realize desulfurization and denitrification,but also achieve the goal of reducing CO_(2)emissions and ironmaking cost.
基金supported by the National Key Research and Development Program of China (Nos.2019YFC1803500 and 2020YFC1910000)Fundamental Research Funds for the Central Universities (Nos.FRF-TP-20-003A1 and FRF-IDRY-20-014).
文摘The development of low-carbon cementitious materials involves the selection of the appropriate raw materials and the transformation of the hydration mechanism.In this study,low-carbon and low-cost cementitious materials were prepared using municipal solid waste incineration fly ash(MSWI FA),blast furnace slag(BFS),and desulfurization gypsum(DFG)as raw materials to reduce clinker usage.Results showed that the compressive strength of K5(mass ratio of BFS:DFG:MSWI FA=7:1:2)after 360 d of curing was 41.49 MPa,with a low leaching concentration of heavy metal residues that meet groundwater Class II standards,a dioxin content of only 25 ngTEG/kg,and a stable pH value ranging between 11 and 11.5.Microscopic analysis revealed a continuous decrease in the Ca/Si atomic ratios of K4(mass ratio of BFS:DFG:MSWI FA:P-I 42.5=42:10:20:28)and K5,i.e.,1.18-1.54 and 1.04-1.23,respectively,with the increase in the hydration age.The highest Al/Si atomic ratio of K5,i.e.,0.26-0.31,was observed with the strongest conversion trend of calcium-silicate-hydrate gel into calcium-aluminum-silicate-hydrate gel,and the network structure of sodium-(calcium)-aluminum-silicate-hydrate gel zeolite-like phase was generated.The water-to-binder(WTB)mass ratio of 0.35 was determined to be more suitable for the K4 and K5 systems and resulted in a 56.83%and 90.82%reduction in half-life ta compared with the WTB ratio of o.5,respectively.Notably,the value of the reaction velocity constant K in the induction period was 10 times that of K1,and the autocatalytic reaction controlled the value of N to<1.The X-ray absorption near-edge structure indicated that Zn solidification produced Zn_(2)SiO_(4) with a small solubility product.The production of 1 t of K5 emitted only 10.83 kg/t of CO_(2),which was 40 times less than that of K1.Overall,K5 provides the highest economic benefit at 40.08 USD/t,and the clinker-free cementitious system with multisolid waste synergy has significant advantages in terms of solidifying harmful substances,reducing carbon emissions,and lowering costs.
基金supported by the National Natural Science Foundation of China(No.52270177)the Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)the Key R&D Plan of Liaoning Province(No.2021JH2/10300103)。
文摘Reducing CO_(2)emissions of the iron and steel industry,a typical heavy CO_(2)-emitting sector is the only way that must be passed to achieve the‘dual-carbon’goal,especially in China.In previous studies,however,it is still unknown what is the difference between blast furnace basic oxygen furnace(BF-BOF),scrap-electric furnace(scrap-EF)and hydrogen metallurgy process.The quantitative research on the key factors affecting CO_(2)emissions is insufficient There is also a lack of research on the prediction of CO_(2)emissions by adjusting industria structure.Based on material flow analysis,this study establishes carbon flow diagrams o three processes,and then analyze the key factors affecting CO_(2)emissions.CO_(2)emissions of the iron and steel industry in the future is predicted by adjusting industrial structure The results show that:(1)The CO_(2)emissions of BF-BOF,scrap-EF and hydrogen metallurgy process in a site are 1417.26,542.93 and 1166.52 kg,respectively.(2)By increasing pellet ratio in blast furnace,scrap ratio in electric furnace,etc.,can effectively reduce CO_(2)emissions(3)Reducing the crude steel output is the most effective CO_(2)reduction measure.There is still 5.15×10^(8)-6.17×10^(8) tons of CO_(2)that needs to be reduced by additional measures.
文摘The possibility of using hydrogen to lower CO 2 emissions in the iron-making process was confirmed by the heat and mass balances in the blast furnace operation. The mass and heat balances for hydrogen utilization in the blast furnace were estimated by using the basic concept of RIST operating diagram. In this study, the RIST operating diagram was modified to be suitable for representing the operation with respect to hydrogen, where the RIST operating diagram is a graphical representation of heat and mass balance in blast furnace operation. RIST operating diagram was applied here to some individual parameters of interest such as H 2 injection in blast furnace process to reduce coke (carbon consumption). It was observed that the point W moved to the right in the RIST operating diagram under the condition of increasing hydrogen injection at tuyere, which originates from the contribution of gas composition (O/H 2 ) equilibrated with Fe/FeO at a certain temperature. Point P also moved downward due to heat requirement with respect to hydrogen utilization, by which the new RIST operating diagram for hydrogen utilization was able to be constructed. Under the condition of hydrogen injection, the expected overall carbon consumption in the blast furnace decreased due to the contribution of hydrogen.
