Increasing production capacity and operating rate, reducing fuel rates and costs of hot metal （HM） are the urgent tasks for the COREX process. In this study ,the various factors on the fuel consumption of COREX are ...Increasing production capacity and operating rate, reducing fuel rates and costs of hot metal （HM） are the urgent tasks for the COREX process. In this study ,the various factors on the fuel consumption of COREX are researched from the theoretical analysis based on the calculations of material balances and heat balances. Combined with the production performances and practices of COREX-2000 （ Saldanha, India） and COREX-3000 （ Baosteel ）, the technical measures of reducing the fuel rate are analyzed and the way forward of technical innovation is addressed and discussed with the standpoint of the COREX process improvement.展开更多
Fuel consumption in the COREX-3000 process run in Baosteel is currently higher than the design index. Therefore, mass and heat balance equations for the COREX process were established using the basic principles in- cl...Fuel consumption in the COREX-3000 process run in Baosteel is currently higher than the design index. Therefore, mass and heat balance equations for the COREX process were established using the basic principles in- cluded in the Rist operating diagram for blast furnace （BF） as a reference. Thermodynamic calculations were then used to modify the Rist operating diagram so that it was suitable for the COREX process. The modified Rist operating dia- gram was then applied for the evaluation of metallization rate （MR） and fuel structure to reduce the energy consump- tion in the COREX process. The modified Rist operating diagram for the shaft furnace （SF） provided a nearly ideal value for the restriction point W when the metallization rate was increased, while the point P on the operating line for the melter gasifier （MG） moved upward due to reduction in the heat required in hearth. The feasibility of reduc- ing the energy consumption during the COREX process by changing the fuel structure was also demonstrated.展开更多
The heat loss and its,distribution are of great importance for the calculation and simulation of COREX process. Based on Baosteel COREX process, a method was applied to measure the heat loss of the furnace shell, the ...The heat loss and its,distribution are of great importance for the calculation and simulation of COREX process. Based on Baosteel COREX process, a method was applied to measure the heat loss of the furnace shell, the accessory equipments and the cooling water system. Then, a static model was established based on the measured heat loss of COREX process. The results showed that the main heat loss of furnace shells took place at the dome of the COREX melter-gasifier and the reducing gas entrance position of the shaft furnace while the main heat loss caused by cooling water occurred at the tap hole area. And the heat loss caused by cooling water accounts for about 85% of the total heat loss in COREX process. The measured total heat loss for producing every 1 t hot metal was 542. 164 MJ, which accounted for about 92 % of the theoretical total heat loss.展开更多
The COREX process is a unique industrialized smelting reduction technology for iron-making presently in the world. One of its striking characteristics is its ability to directly utilize lump coal as its main fuel. The...The COREX process is a unique industrialized smelting reduction technology for iron-making presently in the world. One of its striking characteristics is its ability to directly utilize lump coal as its main fuel. Therefore, the COREX process uses little,or no coke at all. The requirements on lump coal for the COREX process were given in this paper. In order to reduce the coke consumption and give play to the advantages of directly using lump coal ,the appropriate ratio of coke to lump coal needs to be determined. This paper also summerized several advanced methods of using powdered coal generated by the transporting, loading and unloading of lump coal. In order to solve the lack of coal types for COREX and observe the cracking and devolatilization action of lump coal in the melter-gasifier, an experimental device and a new method were proposed to test the cracking and devolatilization characteristics of lump coal. By means of the new method, the devolatilization and cracking behaviors of lump coal can be investigated, which is helpful to the selection of lump coal for the COREX process.展开更多
By analyzing the thermal and burden structure conditions inside the melter-gasifier of COREX process,the advantage and disadvantage of PCI into the melter-gasifier are clarified.The influence of PCI on the running con...By analyzing the thermal and burden structure conditions inside the melter-gasifier of COREX process,the advantage and disadvantage of PCI into the melter-gasifier are clarified.The influence of PCI on the running condition inside the furnace is analyzed based on the information from production operation and mathematical and physical simulations,and measures to tackle with the problems arising from PCI are proposed.The main results are as follows.①Due to the unfavorable conditions for coking of coal in the melter-gasifier,coking of charged lumpy coal to get semicoke with good size and strength can hardly be expected.To maintain the permeability of the burden column,a packed bed similar to blast furnace is necessary.Therefore,a little more coke with PCI in place of most of the lumpy coal may improve the running of the reactor.This can also make the lumpy coal selection easier.②Overall heat balance analysis of the melter-gasifier shows that PCI has no effect on the thermal condition of the furnace as a whole.Local heat balance analysis,however,shows that the heath of the melter-gasifier is in a critical state of low heat supply.PCI into the hearth will deteriorate the thermal condition.To avoid the cooling of the hearth zone by PCI,more oxygen can be blown to the hearth zone,i.e.increase the oxygen supply to the hearth and decrease accordingly the oxygen supply to the freeboard.More oxygen supply to the hearth seems to bring out the issue of an increase in fuel rate and/or thereby the smelting intensity.Detailed analysis of the physical chemical processes concluded that PCI with more corresponding oxygen supply will not lead to the increase of fuel rate.③Comparing with blast furnace,the raceway volume of COREX melter-gasifier is about only 1/10～1/5 of that of corresponding-size blast furnace.This small raceway is not favorable for PCI.To enlarge the raceway to get more favorable condition for PCI,less tuyeres with more oxygen supply of each tuyere is proposed.④Comparing with lumpy coal feeding into the furnace top,PCI into the hearth will increase the heat consumption in the lower part and decrease the heat consumption in the upper part of the furnace,leading to an increase in freeboard temperature,as well as a heat insufficiency of the hearth zone.In addition to more oxygen supply to the hearth,a more active hearth for better heat transfer is thus also indispensible to maintain its thermal condition.This can be realized by greater raceway size and the consequent better central gas flow.⑤PCI from the primary tuyeres into the hearth can increase the gas volume from the raceway.It can also decrease the coal fines from the lumpy coal charged from the furnace top.These are all favorable to improve the central gas flow,and thereby improve the running of the furnace.⑥Comparing with blast furnace,COREX process is capable to easily control the direct reduction ratio of the overall reduction process,and thus,total fuel rate lower than blast furnace is attainable if the pursuance of coke-less operation is not overemphasized.展开更多
文摘Increasing production capacity and operating rate, reducing fuel rates and costs of hot metal （HM） are the urgent tasks for the COREX process. In this study ,the various factors on the fuel consumption of COREX are researched from the theoretical analysis based on the calculations of material balances and heat balances. Combined with the production performances and practices of COREX-2000 （ Saldanha, India） and COREX-3000 （ Baosteel ）, the technical measures of reducing the fuel rate are analyzed and the way forward of technical innovation is addressed and discussed with the standpoint of the COREX process improvement.
基金Item Sponsored by National Natural Science Foundation of China(50934007,50874129)National High-tech Research and Development Program of China(2009AA06Z105)+1 种基金Special Research Foundation of Young Teachers of University of Science and Technology Liaoning of China(2014QN30)Foundation of Liaoning Educational Committee of China(L2015264)
文摘Fuel consumption in the COREX-3000 process run in Baosteel is currently higher than the design index. Therefore, mass and heat balance equations for the COREX process were established using the basic principles in- cluded in the Rist operating diagram for blast furnace （BF） as a reference. Thermodynamic calculations were then used to modify the Rist operating diagram so that it was suitable for the COREX process. The modified Rist operating dia- gram was then applied for the evaluation of metallization rate （MR） and fuel structure to reduce the energy consump- tion in the COREX process. The modified Rist operating diagram for the shaft furnace （SF） provided a nearly ideal value for the restriction point W when the metallization rate was increased, while the point P on the operating line for the melter gasifier （MG） moved upward due to reduction in the heat required in hearth. The feasibility of reduc- ing the energy consumption during the COREX process by changing the fuel structure was also demonstrated.
基金Item Sponsored by National Natural Science Foundation of China(U1260202)Specialized Research Fund for Doctoral Program of Higher Education of China(20120006110002)
文摘The heat loss and its,distribution are of great importance for the calculation and simulation of COREX process. Based on Baosteel COREX process, a method was applied to measure the heat loss of the furnace shell, the accessory equipments and the cooling water system. Then, a static model was established based on the measured heat loss of COREX process. The results showed that the main heat loss of furnace shells took place at the dome of the COREX melter-gasifier and the reducing gas entrance position of the shaft furnace while the main heat loss caused by cooling water occurred at the tap hole area. And the heat loss caused by cooling water accounts for about 85% of the total heat loss in COREX process. The measured total heat loss for producing every 1 t hot metal was 542. 164 MJ, which accounted for about 92 % of the theoretical total heat loss.
文摘The COREX process is a unique industrialized smelting reduction technology for iron-making presently in the world. One of its striking characteristics is its ability to directly utilize lump coal as its main fuel. Therefore, the COREX process uses little,or no coke at all. The requirements on lump coal for the COREX process were given in this paper. In order to reduce the coke consumption and give play to the advantages of directly using lump coal ,the appropriate ratio of coke to lump coal needs to be determined. This paper also summerized several advanced methods of using powdered coal generated by the transporting, loading and unloading of lump coal. In order to solve the lack of coal types for COREX and observe the cracking and devolatilization action of lump coal in the melter-gasifier, an experimental device and a new method were proposed to test the cracking and devolatilization characteristics of lump coal. By means of the new method, the devolatilization and cracking behaviors of lump coal can be investigated, which is helpful to the selection of lump coal for the COREX process.
文摘By analyzing the thermal and burden structure conditions inside the melter-gasifier of COREX process,the advantage and disadvantage of PCI into the melter-gasifier are clarified.The influence of PCI on the running condition inside the furnace is analyzed based on the information from production operation and mathematical and physical simulations,and measures to tackle with the problems arising from PCI are proposed.The main results are as follows.①Due to the unfavorable conditions for coking of coal in the melter-gasifier,coking of charged lumpy coal to get semicoke with good size and strength can hardly be expected.To maintain the permeability of the burden column,a packed bed similar to blast furnace is necessary.Therefore,a little more coke with PCI in place of most of the lumpy coal may improve the running of the reactor.This can also make the lumpy coal selection easier.②Overall heat balance analysis of the melter-gasifier shows that PCI has no effect on the thermal condition of the furnace as a whole.Local heat balance analysis,however,shows that the heath of the melter-gasifier is in a critical state of low heat supply.PCI into the hearth will deteriorate the thermal condition.To avoid the cooling of the hearth zone by PCI,more oxygen can be blown to the hearth zone,i.e.increase the oxygen supply to the hearth and decrease accordingly the oxygen supply to the freeboard.More oxygen supply to the hearth seems to bring out the issue of an increase in fuel rate and/or thereby the smelting intensity.Detailed analysis of the physical chemical processes concluded that PCI with more corresponding oxygen supply will not lead to the increase of fuel rate.③Comparing with blast furnace,the raceway volume of COREX melter-gasifier is about only 1/10～1/5 of that of corresponding-size blast furnace.This small raceway is not favorable for PCI.To enlarge the raceway to get more favorable condition for PCI,less tuyeres with more oxygen supply of each tuyere is proposed.④Comparing with lumpy coal feeding into the furnace top,PCI into the hearth will increase the heat consumption in the lower part and decrease the heat consumption in the upper part of the furnace,leading to an increase in freeboard temperature,as well as a heat insufficiency of the hearth zone.In addition to more oxygen supply to the hearth,a more active hearth for better heat transfer is thus also indispensible to maintain its thermal condition.This can be realized by greater raceway size and the consequent better central gas flow.⑤PCI from the primary tuyeres into the hearth can increase the gas volume from the raceway.It can also decrease the coal fines from the lumpy coal charged from the furnace top.These are all favorable to improve the central gas flow,and thereby improve the running of the furnace.⑥Comparing with blast furnace,COREX process is capable to easily control the direct reduction ratio of the overall reduction process,and thus,total fuel rate lower than blast furnace is attainable if the pursuance of coke-less operation is not overemphasized.
