Effect of CO2 injection into blast furnace tuyeres on the pulverized coal combustion

Abstract

CO2 injection into blast furnace tuyeres is a new technology to utilize CO2, aiming at expanding the way of CO2 self-absorption in the metallurgical industry. The decisive factor of whether CO2 can be mixed into a blast-furnace hot blast and the proper mixing ratio is the effect of CO2 injection on pulverized coal burnout. To investigate the effect of CO2 injection into tuyeres on pulverized coal burnout, a three-dimensional mathematical model of pulverized coal flow and combustion in the lower part of the pulverized coal injection lance-blowpipe-tuyere-raceway was established, and the effect of CO2 injection into tuyeres on pulverized coal combustion rate and outlet temperature is analyzed. The numerical simulation results show that the delay of pulverized coal combustion in the early stage is caused by the endothermic effect of the reaction of CO2 with carbon, and the burnout of pulverized coal is increased in the later stage due to the oxidation of CO2