Numerical Simulation Of Gas Flow Distribution In COREX Shaft Furnace

COREX was the earliest industrialized non-blast furnace ironmaking process,designed to reduce the amount of coke used in the ironmaking process,and reducing pollutant emissions.However,COREX steelmaking process still has some technical problems,.Among them,the charge sticking and the gas flowing back up are important factors affecting the gas flow distribution of shaft furnace.Although the researchers proposed a method to suppress the charge sticking and relieve the phenomenon of the gas flowing back up,the study on the influence of the two methods on the gas flow distribution in the COREX shaft furnace was less.In this paper,according to the experimentally determined method of inhibiting sticking,coating inhibitors on the surface of the pellets,performing data analysis,determining the distribution of voidage in the shaft furnace,and analyzing the effect of coating inhibitors on the gas flow distribution in the shaft furnace.Combining the measures to relieve gas flowing back up,numerical simulation of the gas flow distribution before and after the use of inhibitors in the shaft furnace was conducted to provide a theoretical basis for the development of the COREX process.The main conclusions of the paper are as follows:(1)According to the results of the previous experiments about inhibit sticking.the voidage content of the shaft furnace pellets was analyzed at different experimental temperatures before and after the use of inhibitors.Combined with the temperature distribution in the shaft furnace studied by previous researchers,the voidage distribution in the COREX pre-reduction shaft furnace was determined.When coating inhibitors are used compared to uncoated inhibitors,the voidage at the same location in the shaft furnace is increased.(2)When uncoated inhibitor pellets was used as furnace burden in COREX shaft furnace,the pressure in the furnace gradually increases from top to bottom,the differential pressure in the shaft furnace was 24.88 kPa.When coating inhibitor pellets are used,the differential pressure in the shaft furnace was 20.5k Pa,the reduction of pressure difference compared to uncoated inhibitors was 17.60%,the overall pressure in the shaft furnace is increased,and the operating pressure of the shaft furnace is increased.At the same time,the central air flow rate in the shaft furnace is increased,the gas was easier to reach the center of shaft furnace through space between pellets,and promoting the reduction of the furnace burden.(3)In order to relieve the phenomenon of gas flow back up in the shaft furnace,the internal structure of the shaft furnace was modified and an AGD or CGD was installed in the COREX shaft furnace.Adding AGD or CGD can improve the overall pressure level of the shaft furnace.When the coating inhibitor is installed AGD and is used,the gas flow rate of t shaft furnace center increases,so that the burden in the furnace center area is fully restored,but the volume of the dead gas in the lower part of the shaft furnace is increased.When coating inhibitor was installed and CGD was used,the gas velocity in the lower part of the shaft furnace is effectively increased,but the gas velocity in the upper part of the shaft furnace was reduced.