The molten liquid discrete flow inside a packed bed is a typical transport phenomenon in the blast furnace. As for the reported mathematical models presenting the liquid discrete flow within the packed bed, there are ...The molten liquid discrete flow inside a packed bed is a typical transport phenomenon in the blast furnace. As for the reported mathematical models presenting the liquid discrete flow within the packed bed, there are some barriers for their application to an engineering scale-up, or some imperfections in model descriptions. To overcome these deficiencies, the effects of the packed bed on the liquid discrete flow have been divided into resistance action and dispersal action, and appropriate descriptions have been given for the two aetions, respectively. Consequently, a new mathematical model has been built to present the liquid discrete flow inside a coke bed in the blast furnace. The mathematical model can predict the distribution of liquid flux and the liquid flowing range inside the packed bed at any time. The prediction of this model accords well with the experimental data. The model will be much better for the simulation of the ironmaking process, compared with the existent model.展开更多
The molten liquid flow inside a packed bed is a familiar momentum transportation phenomenon in a blast furnace. With regard to the reported mathematical models describing the liquid flow within a packed bed, there are...The molten liquid flow inside a packed bed is a familiar momentum transportation phenomenon in a blast furnace. With regard to the reported mathematical models describing the liquid flow within a packed bed, there are some obstacles for their application in engineering design, or some limitations in the model itself. To overcome these problems, the forces from the packed bed to the liquid flow were divided into appropriate body and surface forces on the basis of three assumptions. Consequently, a new mathematical model was built to present the liquid flow inside the coke bed in a blast furnace. The mathematical model can predict the distribution of liquid flowrate and the liquid flowing range inside the packed bed at any time. The predicted results of this model accord well with the experimental data. The model will be applied considerably better in the simulation on the ironmaking process compared with the existent models.展开更多
A typical electrode reaction of electro-organic synthesis usually takes place with competing side electrode reaction and homogeneous reaction.To enhance the electrode polarization for increasing reaction rate will con...A typical electrode reaction of electro-organic synthesis usually takes place with competing side electrode reaction and homogeneous reaction.To enhance the electrode polarization for increasing reaction rate will considerably reduce the reaction selectivity.Packed bed electrodes can reach higher current densities at relatively low electrode polarizations,which is favorable to mitigating the inconsistency between reaction rate and selectivity.In this paper,the typical process of electro-organic synthesis in a differential reactor of packed bed electrode(PBEDR),was theoretically analyzed with emphasis on the effect of lateral distribution of over-potential on the selectivity.A generalized mathematical model was developed to describe the distribution of over-potential.Dimensionless variables μ and that characterize the polarization and influence of side electrode reaction in the system,were derived from modeling.Adomian’s decomposition method(ADM)was used to solve the nonlinear differential equation of the model to obtain an approximate analytical solution,which was in the form of algebraic expressions of infinite power series.By the solution,the relationship between over-potential distribution and average selectivity could be easily calculated without solving the nonlinear model time and again.Finally,an analysis of electrochemical reduction of nitrobenzene in a PBEDR was presented,and the characteristic size of the reactor,namely the thickness of the packed bed electrode,was theoretically optimized.The results showed that the calculated results were consistent with experimental data satisfactorily.展开更多
基金Item Sponsored by National Natural Science Foundation of China(50704040)
文摘The molten liquid discrete flow inside a packed bed is a typical transport phenomenon in the blast furnace. As for the reported mathematical models presenting the liquid discrete flow within the packed bed, there are some barriers for their application to an engineering scale-up, or some imperfections in model descriptions. To overcome these deficiencies, the effects of the packed bed on the liquid discrete flow have been divided into resistance action and dispersal action, and appropriate descriptions have been given for the two aetions, respectively. Consequently, a new mathematical model has been built to present the liquid discrete flow inside a coke bed in the blast furnace. The mathematical model can predict the distribution of liquid flux and the liquid flowing range inside the packed bed at any time. The prediction of this model accords well with the experimental data. The model will be much better for the simulation of the ironmaking process, compared with the existent model.
基金supported by the National Natural Science Foundation of China (No.50704040, 20805060)the Natural Science Foundation Project of Chongqing Science & Technology Commission, China (No.CSTC,2009BB4197)
文摘The molten liquid flow inside a packed bed is a familiar momentum transportation phenomenon in a blast furnace. With regard to the reported mathematical models describing the liquid flow within a packed bed, there are some obstacles for their application in engineering design, or some limitations in the model itself. To overcome these problems, the forces from the packed bed to the liquid flow were divided into appropriate body and surface forces on the basis of three assumptions. Consequently, a new mathematical model was built to present the liquid flow inside the coke bed in a blast furnace. The mathematical model can predict the distribution of liquid flowrate and the liquid flowing range inside the packed bed at any time. The predicted results of this model accord well with the experimental data. The model will be applied considerably better in the simulation on the ironmaking process compared with the existent models.
文摘A typical electrode reaction of electro-organic synthesis usually takes place with competing side electrode reaction and homogeneous reaction.To enhance the electrode polarization for increasing reaction rate will considerably reduce the reaction selectivity.Packed bed electrodes can reach higher current densities at relatively low electrode polarizations,which is favorable to mitigating the inconsistency between reaction rate and selectivity.In this paper,the typical process of electro-organic synthesis in a differential reactor of packed bed electrode(PBEDR),was theoretically analyzed with emphasis on the effect of lateral distribution of over-potential on the selectivity.A generalized mathematical model was developed to describe the distribution of over-potential.Dimensionless variables μ and that characterize the polarization and influence of side electrode reaction in the system,were derived from modeling.Adomian’s decomposition method(ADM)was used to solve the nonlinear differential equation of the model to obtain an approximate analytical solution,which was in the form of algebraic expressions of infinite power series.By the solution,the relationship between over-potential distribution and average selectivity could be easily calculated without solving the nonlinear model time and again.Finally,an analysis of electrochemical reduction of nitrobenzene in a PBEDR was presented,and the characteristic size of the reactor,namely the thickness of the packed bed electrode,was theoretically optimized.The results showed that the calculated results were consistent with experimental data satisfactorily.
