As the bed depth increases,sintering yield increases,but the productivity decreases.To reveal the reasons for the decrease in productivity and explore targeted solutions,the bed resistance of mixtures,wet zone,and com...As the bed depth increases,sintering yield increases,but the productivity decreases.To reveal the reasons for the decrease in productivity and explore targeted solutions,the bed resistance of mixtures,wet zone,and combustion zone was analyzed in the laboratory.The results showed that the decreased porosity of mixture resulted in the increased bed resistance by 160.56%when the bed depth increased from 600 to 1000 mm.After improving porosity of 1%by adding loosening bars with optimized size and distribution,the bed resistance decreased,and the productivity increased by 5%.The increase in bed depth increased the thickness of the wet zone from 120 to 680 mm and the resistance from 1.56 to 8.83 kPa.By using a three-stage intensive mixer and pre-adding water for granulation,the moisture of mixture was reduced by 0.6%,and the sintering productivity increased by 4%.Besides,the high bed resistance is mainly caused by the increase in the thickness of the combustion zone from 31.9 to 132.7 mm,and the bed resistance increased from 0.70 to 5.62 kPa.The bed resistance of the combustion zone at 900 mm was increased by 90.51%compared to 700 mm.After optimization of the distribution of coke breeze,the thickness of combustion zone at the lower layer decreased from 132.7 to 106.84 mm and permeability improved significantly.展开更多
Sintering is a critical process in steel production that facilitates the efficient utilization of iron ore resources.However,compared to advanced sintering technologies,China’s sintering methods still exhibit high en...Sintering is a critical process in steel production that facilitates the efficient utilization of iron ore resources.However,compared to advanced sintering technologies,China’s sintering methods still exhibit high energy consumption,with typical solid fuel consumption for sintering of about 55 kg/t.In response,a pellet sintering process has been developed and its behavior has been investigated at sintering bed heights of 750 and 1500 mm.Additionally,a technical and economic comparison with traditional sintering methods has been conducted.The results indicate that at a bed height of 750 mm,the pellet sintering method can significantly reduce solid fuel consumption by approximately 30.82%,dropping from 70.75 to 48.95 kg/t.Additionally,the coke rate decreased from 4.55%to 3.20%,and harmful emissions in the flue gas were also reduced.As the bed height increases to 1500 mm,sintering performance improves even further.The coke rate is reduced to 3.00%,and solid fuel consumption decreases to 41.27 kg/t,approaching the world’s advanced level(≤40 kg/t).Technical and economic analysis also indicates that adopting the pellet sintering process can lower sintering costs by about 2.18 dollars/t.展开更多
Super-high bed sintering process is an important development direction of iron ore sintering for its lower emission and higher yield.However,there is a lack of deep understanding of the uneven quality of super-high be...Super-high bed sintering process is an important development direction of iron ore sintering for its lower emission and higher yield.However,there is a lack of deep understanding of the uneven quality of super-high bed sintering products,and the deterioration of reduction disintegration performance,the thickening of hearth layer and the reduction in energy-saving effect are perplexing enterprises and researchers.To ascertain the problems of super-high bed sintering,ten sintering machines with the areas of 265,280,360,550 and 660 m^(2)and bed depth above 900 mm were sampled and analyzed.The results showed that problems were mainly shown in the unevenness of chemical composition,macrostructure,mechanical strength and metallurgical performance.The chemical composition exhibits severe segregation in both horizontal and vertical directions,with basicity segregation reaching as high as 0.81.The uneven macrostructure of sinter is reflected in a 10%difference in porosity and mechanical strength increase in 16%–19%along the vertical direction.The reducibility and reduction disintegration performance gradually deteriorate along the bed depth,with a difference of 10.5%in reducibility and 7.3%in RDI−0.5 mm(reduction disintegration index of sinter with size smaller than 0.5 mm).展开更多
Horizontal segregation has been a constraint to the development and application of super-high bed sintering.To eliminate the horizontal segregation of super-high bed sintering,several typical sintering machines were s...Horizontal segregation has been a constraint to the development and application of super-high bed sintering.To eliminate the horizontal segregation of super-high bed sintering,several typical sintering machines were sampled and analyzed,and theoretical calculation was made to compare the bed depth and their differences in different areas within the mixture bin.Then,solutions were proposed and applied to a 265 m^(2) sintering machine.The results showed that the horizontal seg-regation of the 265 m^(2) sintering machine was dominated by particles larger than 8 mm with horizontal segregation degree of 0.48,while 360 and 550 m^(2) sintering machines were affected by 5-8 mm and 1-3 mm particles with horizontal segregation degree of 0.27 and 0.31,respectively.Causes analysis indicated the different segregation distribution results from the matching of the bed depth of each area within the mixture bin.Finally,the horizontal segregation degree not larger than 0.06 was achieved by optimizing the time parameters and the division of three zones on the 265 m^(2) sintering machine.展开更多
The inhomogeneous sinter properties in super-high bed sintering have been reported in our previous research.To inves-tigate the reasons for the inhomogeneous phenomena,detailed sampling and analysis of mixed material ...The inhomogeneous sinter properties in super-high bed sintering have been reported in our previous research.To inves-tigate the reasons for the inhomogeneous phenomena,detailed sampling and analysis of mixed material bed and sintered bed in super-high bed sintering plant were executed.The results indicated that the higher porosity and thinner dendrite of silico-ferrite of calcium and aluminum in the upper layer as well as dense structure and higher secondary hematite content in the lower layer led to the heterogeneities of mechanical strength and reduction properties exceeding 20%and 10%,respectively.From the bed top downward,the basicity of mixed material decreased from 2.13 to 1.68 because the average particle size increased from 2.65 to 4.56 mm.Fluxes and fuels gathered in finer particles(-3 mm)of mixed material,and the-3 mm particles of mixed material generated more liquid phase than+3 mm ones.The heat input of super-high sintering bed was inhomogeneous due to the heat accumulation effect and unreasonable fuel distribution.The inhomo-geneous sintering heat condition in sintering bed resulted in the different quantities and properties of liquid phase.The inhomogeneous quantities and properties of liquid phase that were influenced by inhomogeneous distribution of chemical composition,particle size,and heat input led to inhomogeneous mineralizing results.Homogeneous mineralizing condition is the key for homogeneous super-high bed sintering.展开更多
The Taguchi and analysis of variance (ANOVA) methods were applied to investigate the effects of the structural and operational parameters on the heat transfer performance of a vertical sinter cooling packed bed. The a...The Taguchi and analysis of variance (ANOVA) methods were applied to investigate the effects of the structural and operational parameters on the heat transfer performance of a vertical sinter cooling packed bed. The analysed parameters were the gas flow rate, the air inlet temperature, the sinter inlet temperature, the cooling bed diameter and the cooling bed height, all of which contain three levels. The purpose was to improve the heat transfer performance of a vertical sinter cooling bed. A numerical analysis model was established to assess the heat transfer performance with respect to the varying parameters and their different levels. This mathematical model was validated by using data from practical industrial processes. The Taguchi method for the L27 (35) orthogonal design experiment was selected to evaluate the impacts of the design parameters on the heat transfer performance and to acquire the optimum combination of parameters. The analysis of variance was applied to assess the impact weights and the order of significance of the design parameters. The results show that the sinter inlet temperature and cooling bed diameter have great influences and impact the exergy of the wasted heat recovery by 61.65% and 23.31%, respectively. However, the gas flow rate and the air inlet temperature have small effects on the response. Furthermore, the air and sinter inlet temperatures have the most significant impacts on the efficiency of heat transfer by 68.83% and 23.31%, respectively. The optimal parameter combination (A1B1C3D3E3) was obtained, and the optimal results were validated by confirmation tests.展开更多
基金supported by the Basic Science Center Project for the National Natural Science Foundation of China(No.72088101)the S&T Program of Hebei(No.23564101D).
文摘As the bed depth increases,sintering yield increases,but the productivity decreases.To reveal the reasons for the decrease in productivity and explore targeted solutions,the bed resistance of mixtures,wet zone,and combustion zone was analyzed in the laboratory.The results showed that the decreased porosity of mixture resulted in the increased bed resistance by 160.56%when the bed depth increased from 600 to 1000 mm.After improving porosity of 1%by adding loosening bars with optimized size and distribution,the bed resistance decreased,and the productivity increased by 5%.The increase in bed depth increased the thickness of the wet zone from 120 to 680 mm and the resistance from 1.56 to 8.83 kPa.By using a three-stage intensive mixer and pre-adding water for granulation,the moisture of mixture was reduced by 0.6%,and the sintering productivity increased by 4%.Besides,the high bed resistance is mainly caused by the increase in the thickness of the combustion zone from 31.9 to 132.7 mm,and the bed resistance increased from 0.70 to 5.62 kPa.The bed resistance of the combustion zone at 900 mm was increased by 90.51%compared to 700 mm.After optimization of the distribution of coke breeze,the thickness of combustion zone at the lower layer decreased from 132.7 to 106.84 mm and permeability improved significantly.
基金financially supported by Huxiang Youth Talent Program of Hunan Province(No.2024RC3008)National Natural Science Foundation China(Nos.52274343 and 52474370)National Key R&D Program of China(Nos.2023YFC3903900 and 2023YFC3903904).
文摘Sintering is a critical process in steel production that facilitates the efficient utilization of iron ore resources.However,compared to advanced sintering technologies,China’s sintering methods still exhibit high energy consumption,with typical solid fuel consumption for sintering of about 55 kg/t.In response,a pellet sintering process has been developed and its behavior has been investigated at sintering bed heights of 750 and 1500 mm.Additionally,a technical and economic comparison with traditional sintering methods has been conducted.The results indicate that at a bed height of 750 mm,the pellet sintering method can significantly reduce solid fuel consumption by approximately 30.82%,dropping from 70.75 to 48.95 kg/t.Additionally,the coke rate decreased from 4.55%to 3.20%,and harmful emissions in the flue gas were also reduced.As the bed height increases to 1500 mm,sintering performance improves even further.The coke rate is reduced to 3.00%,and solid fuel consumption decreases to 41.27 kg/t,approaching the world’s advanced level(≤40 kg/t).Technical and economic analysis also indicates that adopting the pellet sintering process can lower sintering costs by about 2.18 dollars/t.
基金supported by the National Natural Science Foundation of China(Grant No.52274290)the Basic Science Center Project for the National Natural Science Foundation of China(No.72088101).
文摘Super-high bed sintering process is an important development direction of iron ore sintering for its lower emission and higher yield.However,there is a lack of deep understanding of the uneven quality of super-high bed sintering products,and the deterioration of reduction disintegration performance,the thickening of hearth layer and the reduction in energy-saving effect are perplexing enterprises and researchers.To ascertain the problems of super-high bed sintering,ten sintering machines with the areas of 265,280,360,550 and 660 m^(2)and bed depth above 900 mm were sampled and analyzed.The results showed that problems were mainly shown in the unevenness of chemical composition,macrostructure,mechanical strength and metallurgical performance.The chemical composition exhibits severe segregation in both horizontal and vertical directions,with basicity segregation reaching as high as 0.81.The uneven macrostructure of sinter is reflected in a 10%difference in porosity and mechanical strength increase in 16%–19%along the vertical direction.The reducibility and reduction disintegration performance gradually deteriorate along the bed depth,with a difference of 10.5%in reducibility and 7.3%in RDI−0.5 mm(reduction disintegration index of sinter with size smaller than 0.5 mm).
基金supported by the National Natural Science Foundation of China (Grant No.52274290)the Basic Science Center Project for the National Natural Science Foundation of China (No.72088101).
文摘Horizontal segregation has been a constraint to the development and application of super-high bed sintering.To eliminate the horizontal segregation of super-high bed sintering,several typical sintering machines were sampled and analyzed,and theoretical calculation was made to compare the bed depth and their differences in different areas within the mixture bin.Then,solutions were proposed and applied to a 265 m^(2) sintering machine.The results showed that the horizontal seg-regation of the 265 m^(2) sintering machine was dominated by particles larger than 8 mm with horizontal segregation degree of 0.48,while 360 and 550 m^(2) sintering machines were affected by 5-8 mm and 1-3 mm particles with horizontal segregation degree of 0.27 and 0.31,respectively.Causes analysis indicated the different segregation distribution results from the matching of the bed depth of each area within the mixture bin.Finally,the horizontal segregation degree not larger than 0.06 was achieved by optimizing the time parameters and the division of three zones on the 265 m^(2) sintering machine.
基金This work was supported by the National Natural Science Foundation of China(Grant No.52274290).
文摘The inhomogeneous sinter properties in super-high bed sintering have been reported in our previous research.To inves-tigate the reasons for the inhomogeneous phenomena,detailed sampling and analysis of mixed material bed and sintered bed in super-high bed sintering plant were executed.The results indicated that the higher porosity and thinner dendrite of silico-ferrite of calcium and aluminum in the upper layer as well as dense structure and higher secondary hematite content in the lower layer led to the heterogeneities of mechanical strength and reduction properties exceeding 20%and 10%,respectively.From the bed top downward,the basicity of mixed material decreased from 2.13 to 1.68 because the average particle size increased from 2.65 to 4.56 mm.Fluxes and fuels gathered in finer particles(-3 mm)of mixed material,and the-3 mm particles of mixed material generated more liquid phase than+3 mm ones.The heat input of super-high sintering bed was inhomogeneous due to the heat accumulation effect and unreasonable fuel distribution.The inhomo-geneous sintering heat condition in sintering bed resulted in the different quantities and properties of liquid phase.The inhomogeneous quantities and properties of liquid phase that were influenced by inhomogeneous distribution of chemical composition,particle size,and heat input led to inhomogeneous mineralizing results.Homogeneous mineralizing condition is the key for homogeneous super-high bed sintering.
基金This work is supported by the National Key R&D Program of China(2017 YFB0304200)the National Natural Science Foundation of China(51734004).
文摘The Taguchi and analysis of variance (ANOVA) methods were applied to investigate the effects of the structural and operational parameters on the heat transfer performance of a vertical sinter cooling packed bed. The analysed parameters were the gas flow rate, the air inlet temperature, the sinter inlet temperature, the cooling bed diameter and the cooling bed height, all of which contain three levels. The purpose was to improve the heat transfer performance of a vertical sinter cooling bed. A numerical analysis model was established to assess the heat transfer performance with respect to the varying parameters and their different levels. This mathematical model was validated by using data from practical industrial processes. The Taguchi method for the L27 (35) orthogonal design experiment was selected to evaluate the impacts of the design parameters on the heat transfer performance and to acquire the optimum combination of parameters. The analysis of variance was applied to assess the impact weights and the order of significance of the design parameters. The results show that the sinter inlet temperature and cooling bed diameter have great influences and impact the exergy of the wasted heat recovery by 61.65% and 23.31%, respectively. However, the gas flow rate and the air inlet temperature have small effects on the response. Furthermore, the air and sinter inlet temperatures have the most significant impacts on the efficiency of heat transfer by 68.83% and 23.31%, respectively. The optimal parameter combination (A1B1C3D3E3) was obtained, and the optimal results were validated by confirmation tests.
