It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is brok...It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is broken, and the thermal utilizing efficiency of fuel is reduced, which results in the decrease of yield and tumble index of sinter. Circulating flue gas to sintering bed as biochar replacing 40% coke, CO in flue gas can be reused so as to increase the thermal utilizing efficiency of fuels, and the consistency of two fronts is recovered for the circulating flue gas containing certain CO2, H2 O and lower O2, which contributes to increasing the maximum temperature, extending the high temperature duration time of sintering bed, and results in improving the output and quality of sinter. In the condition of circulating 40% flue gas, the sintering with biomass fuels is strengthened, and the sintering indexes with biomass fuel replacing 40% coke breeze are comparative to those of using coke breeze completely.展开更多
A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke com...A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke combustion.Simulation shows that under practical operating conditions,multi-steady states exist for the catalyst pellets and the catalyst temperature is sensitive to gas temperature.However,at increased mass flow rate or lowered oxygen concentration,multi-steady states will not appear.Under the strong influences of film diffusion,the coke in the packed bed reactor will first be exhausted at the inlet,while if the film diffusion resistance is decreased,the position of first coke exhaustion moves toward the outlet of the reactor.展开更多
Normally, industries in general, produce waste at its majority toxic, such as fly ash, for example, which damage the environment. The aim of this paper is to investigate the evolution of the temperature in a combustio...Normally, industries in general, produce waste at its majority toxic, such as fly ash, for example, which damage the environment. The aim of this paper is to investigate the evolution of the temperature in a combustion reactor, full of pellets manufactured with fly ash, clay and charcoal powder, after sintering, to obtainment synthetic aggregates for use in civil construction. The pellets were produced in a cement mix. For realization of the work, a co-current combustion reactor was made in order to analyze the temperatures profile and investigate if the values of these temperatures would be sufficient to initiate the process of sintering of the pellets. Temperatures reached in the reactor varied in the range of 800 ℃-1,290 ℃. These values are sufficient to initiate the process of sintering of the pellets. For the experiment realized, parameters such as inlet velocity of the fluid （air）, diameters of the pellets and size of charcoal crushed in a disk mill were varied and the effect of variations of these parameters were analyzed for the experiment. The historical temperatures were recorded by a data acquisition instrument and subsequently plotted for analysis.展开更多
基金Projects(51174253,51304245) supported by National Natural Science Foundation of China
文摘It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is broken, and the thermal utilizing efficiency of fuel is reduced, which results in the decrease of yield and tumble index of sinter. Circulating flue gas to sintering bed as biochar replacing 40% coke, CO in flue gas can be reused so as to increase the thermal utilizing efficiency of fuels, and the consistency of two fronts is recovered for the circulating flue gas containing certain CO2, H2 O and lower O2, which contributes to increasing the maximum temperature, extending the high temperature duration time of sintering bed, and results in improving the output and quality of sinter. In the condition of circulating 40% flue gas, the sintering with biomass fuels is strengthened, and the sintering indexes with biomass fuel replacing 40% coke breeze are comparative to those of using coke breeze completely.
基金Supported by the National Natural Science Foundation of China（20736011） the Ministry of Education of China（IRT0721）
文摘A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke combustion.Simulation shows that under practical operating conditions,multi-steady states exist for the catalyst pellets and the catalyst temperature is sensitive to gas temperature.However,at increased mass flow rate or lowered oxygen concentration,multi-steady states will not appear.Under the strong influences of film diffusion,the coke in the packed bed reactor will first be exhausted at the inlet,while if the film diffusion resistance is decreased,the position of first coke exhaustion moves toward the outlet of the reactor.
文摘Normally, industries in general, produce waste at its majority toxic, such as fly ash, for example, which damage the environment. The aim of this paper is to investigate the evolution of the temperature in a combustion reactor, full of pellets manufactured with fly ash, clay and charcoal powder, after sintering, to obtainment synthetic aggregates for use in civil construction. The pellets were produced in a cement mix. For realization of the work, a co-current combustion reactor was made in order to analyze the temperatures profile and investigate if the values of these temperatures would be sufficient to initiate the process of sintering of the pellets. Temperatures reached in the reactor varied in the range of 800 ℃-1,290 ℃. These values are sufficient to initiate the process of sintering of the pellets. For the experiment realized, parameters such as inlet velocity of the fluid （air）, diameters of the pellets and size of charcoal crushed in a disk mill were varied and the effect of variations of these parameters were analyzed for the experiment. The historical temperatures were recorded by a data acquisition instrument and subsequently plotted for analysis.
