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
In order to solve the problems of top-coal inadequate destruction and large amounts of gas emission in mining extra thick and hard coal seam,this study investigated the pre-splitting for deep borehole blasting and gas...In order to solve the problems of top-coal inadequate destruction and large amounts of gas emission in mining extra thick and hard coal seam,this study investigated the pre-splitting for deep borehole blasting and gas pre-draining technologies on top coal.The mechanism of the technologies was systematically expounded based on hard top-coal cracks development obtained by numerical simulation and theoretical analysis.The results show that explosive blasting in the hard rock results in a large number of cracks and large displacement in the rock mass due to the effect of explosion stress.Meanwhile,the thick top-coal caves,and desorbing gas flows along the cracks improve gas extraction.Finally,the pre-splitting for deep borehole blasting and gas pre-draining technologies was applied in No.3802 working face of Shui Liandong Coal Mine,which increases monthly output in the face to 67.34 kt and the drained gas concentration to 86.2%.The drained gas average concentration from each borehole reaches 40%,and the effect is remarkable.展开更多
The circumferential burden distribution of bell-less top with two parallel hoppers was analyzed to obtain the expressions of burden flux and uneven ratio. The four-batch feeding spirally with two parallel hoppers was ...The circumferential burden distribution of bell-less top with two parallel hoppers was analyzed to obtain the expressions of burden flux and uneven ratio. The four-batch feeding spirally with two parallel hoppers was proposed to realize even burden distribution by uneven flux, ensuring reasonable distribution of BF gas and effective usage of heat energy and chemical energy of gas as well as stable BF production with higher quality and lower consumption.展开更多
The influence of material gate position in bur- den-flow rate has been studied by simulating exper- iments.A mathematical model describing the char- acteristics of burden-flow at the material gate of bell-less top bla...The influence of material gate position in bur- den-flow rate has been studied by simulating exper- iments.A mathematical model describing the char- acteristics of burden-flow at the material gate of bell-less top blast furnace(BF)is established in this paper,in an attempt to solve the problems in bur- den distribution,especially to eliminate the over- lapping or disconnection of the burden at the be- ginning and at the end of a ring,which plays a quite important role in the blast furnace operation.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financially supported by the National Natural Science Fund of China(Nos.51004003 and 51474009)Anhui Province Education Department Natural Science Fund Key Project of China(No.KJ2010A091)
文摘In order to solve the problems of top-coal inadequate destruction and large amounts of gas emission in mining extra thick and hard coal seam,this study investigated the pre-splitting for deep borehole blasting and gas pre-draining technologies on top coal.The mechanism of the technologies was systematically expounded based on hard top-coal cracks development obtained by numerical simulation and theoretical analysis.The results show that explosive blasting in the hard rock results in a large number of cracks and large displacement in the rock mass due to the effect of explosion stress.Meanwhile,the thick top-coal caves,and desorbing gas flows along the cracks improve gas extraction.Finally,the pre-splitting for deep borehole blasting and gas pre-draining technologies was applied in No.3802 working face of Shui Liandong Coal Mine,which increases monthly output in the face to 67.34 kt and the drained gas concentration to 86.2%.The drained gas average concentration from each borehole reaches 40%,and the effect is remarkable.
文摘The circumferential burden distribution of bell-less top with two parallel hoppers was analyzed to obtain the expressions of burden flux and uneven ratio. The four-batch feeding spirally with two parallel hoppers was proposed to realize even burden distribution by uneven flux, ensuring reasonable distribution of BF gas and effective usage of heat energy and chemical energy of gas as well as stable BF production with higher quality and lower consumption.
文摘The influence of material gate position in bur- den-flow rate has been studied by simulating exper- iments.A mathematical model describing the char- acteristics of burden-flow at the material gate of bell-less top blast furnace(BF)is established in this paper,in an attempt to solve the problems in bur- den distribution,especially to eliminate the over- lapping or disconnection of the burden at the be- ginning and at the end of a ring,which plays a quite important role in the blast furnace operation.
