Rotary kiln process for iron ore oxide pellet production is hard to detect and control.Construction of one-dimensional model of temperature field in rotary kiln was described.And the results lay a solid foundation for...Rotary kiln process for iron ore oxide pellet production is hard to detect and control.Construction of one-dimensional model of temperature field in rotary kiln was described.And the results lay a solid foundation for online control.Establishment of kiln process control expert system was presented,with maximum temperature of pellet and gas temperature at the feed end as control cores,and interval estimate as control strategy.Software was developed and put into application in a pellet plant.The results show that control guidance of this system is accurate and effective.After production application for nearly one year,the compressive strength and first grade rate of pellet are increased by 86 N and 2.54%,respectively,while FeO content is 0.05% lowered.This system can reveal detailed information of real time kiln process,and provide a powerful tool for online control of pellet production.展开更多
A mathematical model to predict the operation behaviours of the rotary kiln process and to describe the axial distribution of process variables along the length of the reactor has been developed in present work.The mo...A mathematical model to predict the operation behaviours of the rotary kiln process and to describe the axial distribution of process variables along the length of the reactor has been developed in present work.The model is established based on the principle of mass and heat balance in the system under a steady state with the consideration of kinetic characteristics of the processes.Four examples of the simulation processes in a pi- lot kiln and 3 commercial kilns by using the present mathematical model are given in this paper.The good agreement between the predicted results and the measured data has been obtained.展开更多
Direct reduction of dust composite pellets containing zinc and iron was examined by simulating the conditions of actual production process of a rotary hearth furnace （RHF） in laboratory. A mathematical model was con...Direct reduction of dust composite pellets containing zinc and iron was examined by simulating the conditions of actual production process of a rotary hearth furnace （RHF） in laboratory. A mathematical model was constructed to study the reduction kinetics of iron oxides and ZnO in the dust composite pellets. It was validated by comparing the calculated values with experimental results. The effects of furnace temperature, pellet radius, and pellet porosity on the reduction were investigated by the model. It is shown that furnace temperature has obvious influence on both of the reduction of iron oxides and ZnO, but the influence of pellet radius and porosity is much smaller. Model calculations suggest that both of the reduction of iron oxides and ZnO are under mixed control with interface reactions and Boudouard reaction in the early stage, but only with interface reactions in the later stage.展开更多
Based on conduction,convection and radiation heat transfer among the flue gas,kiln wall,and the pellet bed material,and on the basis of the coal combustion and analysis of reaction heat of pellet induration in the rot...Based on conduction,convection and radiation heat transfer among the flue gas,kiln wall,and the pellet bed material,and on the basis of the coal combustion and analysis of reaction heat of pellet induration in the rotary kiln,the temperature field model of rotary kiln was established.Using visual studio net,matlab and open source computer vision library as development tools,combining with the ActiveX data objects database technology,the temperature field simulation system for rotary kiln of iron ore oxidized pellet production was developed.Temperature distribution of pellet and flue gas in rotary kiln was dynamically displayed.展开更多
In this study,innovative ellipsoid pellet with craters on its surface was designed,and the direct reduction process was compared with ellipsoid(without craters)and sphere pellets.In addition,furnace temperature and un...In this study,innovative ellipsoid pellet with craters on its surface was designed,and the direct reduction process was compared with ellipsoid(without craters)and sphere pellets.In addition,furnace temperature and uneven heat flux density effects on the pellet direct reduction process were also studied.The results show that ellipsoid pellet is better than that of spherical pellet on metallization ratio.However,under the condition of non-uniform heat flow,the ellipsoid pellet final metallization rate and zinc removal rate were lower.Although the heat transfer effect of ellipsoid pellet with craters was not improved significantly,the metallization rate and zinc removal rate were found improved,which will have a cumulative effect on the pellets direct reduction process in rotary hearth furnace.Under varying furnace temperature conditions,the pellet temperature was higher than that of the constant furnace temperature.After 1200 s,pellet Fe concentration increased to 123.6%,metallization rate and zinc removal rate increased to 113.7%and 102.2%,respectively.These results can provide references for the carbon-containing pellet design used in rotary hearth furnace.展开更多
基金Project(NCET-05-0630) supported by Program for New Century Excellent Talents in University of China
文摘Rotary kiln process for iron ore oxide pellet production is hard to detect and control.Construction of one-dimensional model of temperature field in rotary kiln was described.And the results lay a solid foundation for online control.Establishment of kiln process control expert system was presented,with maximum temperature of pellet and gas temperature at the feed end as control cores,and interval estimate as control strategy.Software was developed and put into application in a pellet plant.The results show that control guidance of this system is accurate and effective.After production application for nearly one year,the compressive strength and first grade rate of pellet are increased by 86 N and 2.54%,respectively,while FeO content is 0.05% lowered.This system can reveal detailed information of real time kiln process,and provide a powerful tool for online control of pellet production.
文摘A mathematical model to predict the operation behaviours of the rotary kiln process and to describe the axial distribution of process variables along the length of the reactor has been developed in present work.The model is established based on the principle of mass and heat balance in the system under a steady state with the consideration of kinetic characteristics of the processes.Four examples of the simulation processes in a pi- lot kiln and 3 commercial kilns by using the present mathematical model are given in this paper.The good agreement between the predicted results and the measured data has been obtained.
基金financially supported by the National Basic Research Program of China (No. 2012CB720401)the National Key Technology Research and Development Program of China (No. 2011BAC01B02)
文摘Direct reduction of dust composite pellets containing zinc and iron was examined by simulating the conditions of actual production process of a rotary hearth furnace （RHF） in laboratory. A mathematical model was constructed to study the reduction kinetics of iron oxides and ZnO in the dust composite pellets. It was validated by comparing the calculated values with experimental results. The effects of furnace temperature, pellet radius, and pellet porosity on the reduction were investigated by the model. It is shown that furnace temperature has obvious influence on both of the reduction of iron oxides and ZnO, but the influence of pellet radius and porosity is much smaller. Model calculations suggest that both of the reduction of iron oxides and ZnO are under mixed control with interface reactions and Boudouard reaction in the early stage, but only with interface reactions in the later stage.
基金Sponsored by Program for New Century Excellent Talents in University of China(NCET-05-0630)
文摘Based on conduction,convection and radiation heat transfer among the flue gas,kiln wall,and the pellet bed material,and on the basis of the coal combustion and analysis of reaction heat of pellet induration in the rotary kiln,the temperature field model of rotary kiln was established.Using visual studio net,matlab and open source computer vision library as development tools,combining with the ActiveX data objects database technology,the temperature field simulation system for rotary kiln of iron ore oxidized pellet production was developed.Temperature distribution of pellet and flue gas in rotary kiln was dynamically displayed.
基金Project(cstc 2018 jszx-cyzdx 0100)supported by the Chongqing Technology Innovation and Application Demonstration Project,China。
文摘In this study,innovative ellipsoid pellet with craters on its surface was designed,and the direct reduction process was compared with ellipsoid(without craters)and sphere pellets.In addition,furnace temperature and uneven heat flux density effects on the pellet direct reduction process were also studied.The results show that ellipsoid pellet is better than that of spherical pellet on metallization ratio.However,under the condition of non-uniform heat flow,the ellipsoid pellet final metallization rate and zinc removal rate were lower.Although the heat transfer effect of ellipsoid pellet with craters was not improved significantly,the metallization rate and zinc removal rate were found improved,which will have a cumulative effect on the pellets direct reduction process in rotary hearth furnace.Under varying furnace temperature conditions,the pellet temperature was higher than that of the constant furnace temperature.After 1200 s,pellet Fe concentration increased to 123.6%,metallization rate and zinc removal rate increased to 113.7%and 102.2%,respectively.These results can provide references for the carbon-containing pellet design used in rotary hearth furnace.
