A computational fluid dynamics(CFD)model was developed to accurately predict the flash reduction process,which is considered an efficient alternative ironmaking process.Laboratory-scale experiments were conducted in d...A computational fluid dynamics(CFD)model was developed to accurately predict the flash reduction process,which is considered an efficient alternative ironmaking process.Laboratory-scale experiments were conducted in drop tube reactors to verify the accuracy of the CFD model.The reduction degree of ore particles was selected as a critical indicator of model prediction,and the simulated and experimental results were in good agreement.The influencing factors,including the particle size(20–110μm),peak temperature(1250–1550°C),and reductive atmosphere(H_(2)/CO),were also investigated.The height variation lines indicated that small particles(50μm)had a longer residence time(3.6 s)than large particles.CO provided a longer residence time(~1.29 s)than H_(2)(~1.09 s).However,both the experimental and analytical results showed that the reduction degree of particles in CO was significantly lower than that in H2 atmosphere.The optimum experimental particle size and peak temperature for the preparation of high-quality reduced iron were found to be 50μm and 1350°C in H2 atmosphere,and40μm and 1550°C in CO atmosphere,respectively.展开更多
Different mathematical models for ethylene furnace reactor tubes were reviewed. On the basis of these models a new mathematical simulation approach for reactor tubes based on computational fluid dynamics （CFD） techn...Different mathematical models for ethylene furnace reactor tubes were reviewed. On the basis of these models a new mathematical simulation approach for reactor tubes based on computational fluid dynamics （CFD） technique was presented. This approach took the flow, heat transfer, mass transfer and thermal cracking reactions in the reactor tubes into consideration. The coupled reactor model was solved with the SIMPLE algorithm. Some detailed information about the flow field, temperature field and concentration distribution in the reactor tubes was obtained, revealing the basic characteristics of the hydrodynamic phenomena and reaction behavior in the reactor tubes. The CFD approach provides the necessary information for conclusive decisions regarding the production optimization, the design and improvement of reactor tubes, and the new techniques implementation.展开更多
A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conservation, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gas vel...A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conservation, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gas velocity, the cross areas of riser and downcomer, gas hold-up and the local frictional loss coefficient. The experimental data indicate that either increase of gas flow rate or reduction of the downcomer diameter contributes to higher liquid circulation rate. The correlation between total and the local frictional loss coefficients was also established.Effects of gas flowrate in two risers and diameter of downcomer on the liquid circulation rate were examined. The value of total frictional loss coefficient was measured as a function of the cross area of downcomer and independent of the gas flow rate. The calculated results of liquid circulation rates agreed well with the experimental data with an average relative error of 9.6%.展开更多
1 INTRODUCTIONMany different types of reactors,for example,fixed bed,moving bed,fluidized bed and spoutedbed,have been used in industrial production and laboratory in research studies.Althougheach of these coal gasifi...1 INTRODUCTIONMany different types of reactors,for example,fixed bed,moving bed,fluidized bed and spoutedbed,have been used in industrial production and laboratory in research studies.Althougheach of these coal gasifiers has its own specific advantages,there exists,generally speaking,certainwaste gas in product gas because of the direct burning of coal with oxygen or air to provide heatneeded in the endothermic process of coal gasification in gasifiers.A new type of moving展开更多
基金financially supported by the National Key Research and Development Project(No.2016YFB0601304)the National Natural Science Foundation of China(No.51804030)。
文摘A computational fluid dynamics(CFD)model was developed to accurately predict the flash reduction process,which is considered an efficient alternative ironmaking process.Laboratory-scale experiments were conducted in drop tube reactors to verify the accuracy of the CFD model.The reduction degree of ore particles was selected as a critical indicator of model prediction,and the simulated and experimental results were in good agreement.The influencing factors,including the particle size(20–110μm),peak temperature(1250–1550°C),and reductive atmosphere(H_(2)/CO),were also investigated.The height variation lines indicated that small particles(50μm)had a longer residence time(3.6 s)than large particles.CO provided a longer residence time(~1.29 s)than H_(2)(~1.09 s).However,both the experimental and analytical results showed that the reduction degree of particles in CO was significantly lower than that in H2 atmosphere.The optimum experimental particle size and peak temperature for the preparation of high-quality reduced iron were found to be 50μm and 1350°C in H2 atmosphere,and40μm and 1550°C in CO atmosphere,respectively.
文摘Different mathematical models for ethylene furnace reactor tubes were reviewed. On the basis of these models a new mathematical simulation approach for reactor tubes based on computational fluid dynamics （CFD） technique was presented. This approach took the flow, heat transfer, mass transfer and thermal cracking reactions in the reactor tubes into consideration. The coupled reactor model was solved with the SIMPLE algorithm. Some detailed information about the flow field, temperature field and concentration distribution in the reactor tubes was obtained, revealing the basic characteristics of the hydrodynamic phenomena and reaction behavior in the reactor tubes. The CFD approach provides the necessary information for conclusive decisions regarding the production optimization, the design and improvement of reactor tubes, and the new techniques implementation.
基金Supported by Liaoning Provincial Natural Science Foundation(No.972050).
文摘A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conservation, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gas velocity, the cross areas of riser and downcomer, gas hold-up and the local frictional loss coefficient. The experimental data indicate that either increase of gas flow rate or reduction of the downcomer diameter contributes to higher liquid circulation rate. The correlation between total and the local frictional loss coefficients was also established.Effects of gas flowrate in two risers and diameter of downcomer on the liquid circulation rate were examined. The value of total frictional loss coefficient was measured as a function of the cross area of downcomer and independent of the gas flow rate. The calculated results of liquid circulation rates agreed well with the experimental data with an average relative error of 9.6%.
文摘1 INTRODUCTIONMany different types of reactors,for example,fixed bed,moving bed,fluidized bed and spoutedbed,have been used in industrial production and laboratory in research studies.Althougheach of these coal gasifiers has its own specific advantages,there exists,generally speaking,certainwaste gas in product gas because of the direct burning of coal with oxygen or air to provide heatneeded in the endothermic process of coal gasification in gasifiers.A new type of moving
