The technology of coal gasification in shaft furnace is an effective way to develop direct reduction iron in China. In order to clarify the process of the reduction of oxidized pellets in shaft furnace by carbon monox...The technology of coal gasification in shaft furnace is an effective way to develop direct reduction iron in China. In order to clarify the process of the reduction of oxidized pellets in shaft furnace by carbon monoxide or hydrogen in two ways, i.e. thermodynamics and kinetics, the gas utilization and reaction mechanism were studied by theoretical computations and isothermal thermogravimetric experiment. The results showed that the gas utilization increased with the rise of temperature when xH2/xco≥1 and with the increase of xco/（xH2 ＋xco） when temperature is less than 1073 K. The water-gas shift reaction restrains efficient utilization of gas, particularly in high tem- perature and hydrogen-rich gas. The gas utilization dropped with increase of carburization quantity of direct reduction iron （DRI） and oxygen potential of atmosphere. With the increase of both temperature and content of H2 in inlet gas, the reaction rate increased. At 100% Hz atmosphere, the interfacial chemical reaction is the dominant reaction re- stricted step. For the H2-CO mixture atmosphere, the reduction process is controlled by both interfacial chemical reaction and internal diffusion展开更多
In recent years, the reformed coke oven gas (COG) was proposed to be used as reducing gas in a shaft furnace. A mathematical model of gas flow based on the reformed COG was built. The effects of the pressure ratio of ...In recent years, the reformed coke oven gas (COG) was proposed to be used as reducing gas in a shaft furnace. A mathematical model of gas flow based on the reformed COG was built. The effects of the pressure ratio of reducing gas to cooling gas (k) on the gas distribution in the shaft furnace were investigated. The calculation results show that k is an important operation parameter, which can obviously affect the gas distribution in the shaft furnace. The value of k should be compromised. Both too big and too small k values are not appropriate, and the most reasonable value for k is 1:1.33.Under this condition, the utilization coefficient of reducing gas, the utilization coefficient of cooling gas and the coefficient of upward gas are 0.94, 0.92 and 1.03, respectively. Based on the validation of physical experiments, the calculated values of the model agreed well with the physical experimental data. Thus, the established model can properly describe the reformed COG distribution in an actual shaft furnace.展开更多
基金Item Sponsored by National Natural Science Foundation of China(51090384)Fundamental Research Funds for Central Universities of China(N110202001)
文摘The technology of coal gasification in shaft furnace is an effective way to develop direct reduction iron in China. In order to clarify the process of the reduction of oxidized pellets in shaft furnace by carbon monoxide or hydrogen in two ways, i.e. thermodynamics and kinetics, the gas utilization and reaction mechanism were studied by theoretical computations and isothermal thermogravimetric experiment. The results showed that the gas utilization increased with the rise of temperature when xH2/xco≥1 and with the increase of xco/（xH2 ＋xco） when temperature is less than 1073 K. The water-gas shift reaction restrains efficient utilization of gas, particularly in high tem- perature and hydrogen-rich gas. The gas utilization dropped with increase of carburization quantity of direct reduction iron （DRI） and oxygen potential of atmosphere. With the increase of both temperature and content of H2 in inlet gas, the reaction rate increased. At 100% Hz atmosphere, the interfacial chemical reaction is the dominant reaction re- stricted step. For the H2-CO mixture atmosphere, the reduction process is controlled by both interfacial chemical reaction and internal diffusion
基金The financial supports of the National Natural Science Foundation of China(NSFC 51874080,NSFC 62001312,NSFC 51774071 and NSFC 51974073)Natural Science Foun-dation of Liaoning(2019-MS-132)are much appreciated.
文摘In recent years, the reformed coke oven gas (COG) was proposed to be used as reducing gas in a shaft furnace. A mathematical model of gas flow based on the reformed COG was built. The effects of the pressure ratio of reducing gas to cooling gas (k) on the gas distribution in the shaft furnace were investigated. The calculation results show that k is an important operation parameter, which can obviously affect the gas distribution in the shaft furnace. The value of k should be compromised. Both too big and too small k values are not appropriate, and the most reasonable value for k is 1:1.33.Under this condition, the utilization coefficient of reducing gas, the utilization coefficient of cooling gas and the coefficient of upward gas are 0.94, 0.92 and 1.03, respectively. Based on the validation of physical experiments, the calculated values of the model agreed well with the physical experimental data. Thus, the established model can properly describe the reformed COG distribution in an actual shaft furnace.
