Study on the Appropriate Production Parameters of a Gas-injection Blast Furnace

The change regulations of the smelting parameters in a gas-injection blast furnace are investigated using theoretical calculations. The results show that when the volume of gas injected, the oxygen enrichment rate and the theoretical combustion temperature of tuyere are 600 m3/tHM, 10% and 1950~2200∘C, respectively, the conditions meet the smelting requirements of a blast furnace. With the increase of the oxygen enrichment rate, the required air volume decreases, the contents of CO and H2 in the top gas increase, and the content of CO2 first increases and then decreases.With an increase of the volume of gas injected, the coke rate decreases. In addition, when the oxygen enrichment rate and the volume of gas injected are 10% and 600 m3/tHM, respectively, the CO content of the top gas constantly increases with the increase of the coke rate, while the H2 and CO2 contents both decrease. With the increase of the H2 content in the gas, the direct reduction degree of iron gradually decreases and the volume shrinkage burden increases. Apparently, injecting gas into the blast furnace can prevent the theoretical combustion temperature from being too high and solve the contradiction between the upper cooling and lower heating of the blast furnace.

Comprehensive Mathematical Model of Full Oxygen Blast Furnace with Top Recycle Gas Heated by Gasifier

A comprehensive mathematical model of full oxygen blast furnace with top recycle gas heated by gasifier was established. The model consists of the calculation equations for gas composition of four zones (hearth, belly, lower shaft, top) in the blast furnace, the thermo-chemical balance model of blast furnace, the energy balance model of hot stand-by zone of blast furnace, the shaft efficiency model of blast furnace, the calculation equations for gas composition of gasifier and the thermo-chemical balance model of gasifier. By using this model, the new process was calculated. The results show that coke rate and coal rate of the new process are 200 kg/thm and 190 kg/thm respectively, fuel rate is decreased by 24.7% compared with that of conventional blast furnace. In addition, theoretical combustion temperature decreases with increasing hearth-recycle gas quantity. Increasing of hearth-recycle gas quantity by 10 m3/thm decreases theoretical combustion temperature by 11.6 K. Furthermore, the model could be applied to calculate the operating parameters when the raw materials and fuel conditions are different, and the changing laws of operating parameters under the same raw materials and fuel conditions could also be studied with this model.

Comprehensive Mathematical Model of Full Oxygen Blast Furnace and its Solution

A comprehensive mathematical model of full blast furnace with top gas recycling was established. The model consists of the calculation equations for gas composition of four zones (hearth, belly, lower shaft. top) in the blast furnace, the thermo-chemical balance model, the energy balance model of hot stand-by zone of the blast furnace and the shaft efficiency model. By using the model, the new process was calculated. The results show that coke rate and coal rate of the new process are both 200 kg/thm, fuel rate is decreased by 22.8% compared with that of conventional blast furnace. In addition, theoretical combustion temperature decreases with increasing hearth-recycle gas quantity. Increasing of hearth-recycle gas quantity by 10 m3/thm decreases theoretical combustion temperature by 10.0 K. Furthermore, the model could be applied to calculate the operating parameters when the raw materials and fuel conditions are different, and the change laws of operating parameters under the same raw materials and fuel conditions could also be studied with this model.