Owing to a certain angle existing between a belt conveyor and the parallel hoppers,and the hoppers localizing away from the centerlines of a blast furnace,particles size segregation is likely to happen in a bell-less ...Owing to a certain angle existing between a belt conveyor and the parallel hoppers,and the hoppers localizing away from the centerlines of a blast furnace,particles size segregation is likely to happen in a bell-less top blast furnace with parallel hoppers.Mastering the law of particles size segregation in hoppers could help to choose better charging parameters and optimize production and technical indices.As for the previous works on burden segregation at a bell-less top blast furnace with parallel hoppers,more attention was paid to the falling point segregation and the circumferential mass flow segregation while charging from the tilting chute,but ignoring the particle size segregation in burden hoppers as burden falls from a belt conveyor,which is the right basis of analyzing the former,and plays a significant role in controlling the gas distribution in the blast furnace.The present work takes ternary mixtures of coke in three different particle sizes to simulate the size segregation of the coke charged into the hoppers by experiments.The effect of the main striking point on size segregation is also investigated.The research shows that there exists a good linear relation between segregation coefficient k and the dimensionless main striking point when using the equation C = C_0~k to express the degree of size segregation in hoppers.The linear relation is proposed for the first time and provides a new way to predict the size segregation in hoppers,which forms a theoretical basis and technical support for reducing the size segregation degree in hoppers.展开更多
The combustion behavior of bamboo char and its relationship with particle sizes were evaluated using thermo-gravimetric analysis.The results showed that the combustion properties of bamboo char were much better than t...The combustion behavior of bamboo char and its relationship with particle sizes were evaluated using thermo-gravimetric analysis.The results showed that the combustion properties of bamboo char were much better than those of the anthracite used as a coal injected for blast furnace ironmaking due to its porous structure,disordered microcrystalline and higher catalytic index of ash minerals.When the particle size increased from -0.074 to 0.500-1.000 mm,the ignition temperature and burnout temperature of bamboo char increased,while the combustible index and comprehensive combustion characteristic index decreased slightly.The apparent activation energies of non-isothermal combustion of bamboo char and anthracite were calculated based on the distributed activation energy model.The results showed that the average activation energy was 162.86 kJ/mol for-0.074 mm anthracite,while it ranged from 71.01 to 89.44 kJ/mol for bamboo chars of different sizes.It revealed that the combustion reactivity of bamboo char in the largest size (0.500-1.000 mm)was much better than that of -0.074 mm,anthracite;thus,the size of biomass char could be enlarged to the maximum size specified by the injection application of blast furnace.展开更多
文摘Owing to a certain angle existing between a belt conveyor and the parallel hoppers,and the hoppers localizing away from the centerlines of a blast furnace,particles size segregation is likely to happen in a bell-less top blast furnace with parallel hoppers.Mastering the law of particles size segregation in hoppers could help to choose better charging parameters and optimize production and technical indices.As for the previous works on burden segregation at a bell-less top blast furnace with parallel hoppers,more attention was paid to the falling point segregation and the circumferential mass flow segregation while charging from the tilting chute,but ignoring the particle size segregation in burden hoppers as burden falls from a belt conveyor,which is the right basis of analyzing the former,and plays a significant role in controlling the gas distribution in the blast furnace.The present work takes ternary mixtures of coke in three different particle sizes to simulate the size segregation of the coke charged into the hoppers by experiments.The effect of the main striking point on size segregation is also investigated.The research shows that there exists a good linear relation between segregation coefficient k and the dimensionless main striking point when using the equation C = C_0~k to express the degree of size segregation in hoppers.The linear relation is proposed for the first time and provides a new way to predict the size segregation in hoppers,which forms a theoretical basis and technical support for reducing the size segregation degree in hoppers.
基金the financial-support from the China Postdoctoral Science Foundation (2016M602378)National Natural Science Foundation of China (Nos.51704216 and U1760101).
文摘The combustion behavior of bamboo char and its relationship with particle sizes were evaluated using thermo-gravimetric analysis.The results showed that the combustion properties of bamboo char were much better than those of the anthracite used as a coal injected for blast furnace ironmaking due to its porous structure,disordered microcrystalline and higher catalytic index of ash minerals.When the particle size increased from -0.074 to 0.500-1.000 mm,the ignition temperature and burnout temperature of bamboo char increased,while the combustible index and comprehensive combustion characteristic index decreased slightly.The apparent activation energies of non-isothermal combustion of bamboo char and anthracite were calculated based on the distributed activation energy model.The results showed that the average activation energy was 162.86 kJ/mol for-0.074 mm anthracite,while it ranged from 71.01 to 89.44 kJ/mol for bamboo chars of different sizes.It revealed that the combustion reactivity of bamboo char in the largest size (0.500-1.000 mm)was much better than that of -0.074 mm,anthracite;thus,the size of biomass char could be enlarged to the maximum size specified by the injection application of blast furnace.
