Numerical simulation and optimization of pulverized coal injection with enriched oxygen into blast furnace

The combustion characteristics of pulverized coal in the blast furnace raceway is an important factor which determines the performance of injection of pulverized coal with enriched oxygen as well as the energy consumption of blast furnace. Research was carried out to investigate processes including the gas and solid flow, particle movement, drying and pyrolysis of pulverized coal and combustion of carbon residue and coke in a blast furnace with standard k–ɛ model, discrete phase model, evaporation and diffusion model, dual parallel competition model and diffusion-kinetic combustion model respectively in Fluent 6.3. The accuracy and reliability of the numerical model was verified with a semi-industrial experiment. Moreover, 7 parameters were optimized by the orthogonal experiments, taking the burnout rate as the evaluation indicator. Results show that the burnout rate under the optimal condition can be increased by 110.8% comparing to that under the standard condition. The importance of parameters influencing the evaluation indicator is found in the order which is the type of the pulverized coal, the pulverized coal injection rate, the oxygen enrichment rate, the blast temperature, the spraying gun type, the blast volume and the angle. •We have established a mathematical model of combustion process in blast furnace.•The gas velocity distribution and motion characteristics of pulverized coal in raceway and coke bed were obtained.•We have developed the optimal parameters combination in purpose of increasing burnout rate.