Aiming at the incomplete utilization of chemical energy of reducing gas in a shaft furnace like Midrex for direct reduced iron production

oxygen blowing into the upper part of the furnace was proposed to transform the excessive chemical energy into thermal energy.In this way

the proportioning and balancing between chemical and thermal energies of reducing gas in the furnace could be realized

and their maximum utilization and thus gas consumption reduction could be expected.A mass and heat balances model was developed to analyze the gas consumption of both traditional and newly proposed processes.A one-dimensional kinetic model was developed to calculate the composition and temperature profiles of both gas and solid phases in the furnace.The distribution of thermodynamic excess

i.e.the excessive chemical energy of reducing gas was also obtained.The results showed that with oxygen blowing into the upper part of the furnace

the temperatures of both gas and solid phases increased and the concentrations of CO and H2 decreased

and thus gas utilization was increased significantly.In the case of 536.40 m3穐-1 oxygen blowing at the furnace height of 6.5m

gas consumption decreased by 25.94% and off-gas reduction potential decreased by 53.69%.