Simulation, Validation, and Prediction of Pellet Reduction Kinetics in a Non-isothermal Fixed Bed
摘要
The gas–solid reduction behavior of pellets warrants additional investigation, particularly during large adjustments to operation parameters in low-carbon ironmaking processes. To address the limitation of the isothermal fixed bed and difficulty in establishment of prediction model, a complex mathematical model of a non-isothermal fixed bed was constructed, using the earlier proposed intrinsic kinetic parameters. The calculations from the constructed model were in good agreement with the results of laboratory experiments, with a relative error of less than 5.59 pct. In the oxygen blast furnace top gas recovery process, the impact of major changes in blast furnace operation needs further inspection. When the CO + N2 ratio was altered from 4 + 8 to 6 + 6 L/min at 1326 K, the bed distribution remained constant, but the time it took to reach 80 pct was lowered by 115 minutes. The mathematical model predicted the influences of temperature, reducing atmosphere, particle size, and equivalent voidage on the distribution of reduction degree in the fixed bed, providing important laboratory understandings for further establishing an intrinsic, inferential, less hypothetical, prediction-oriented, and convergence-independent model for the blast furnace.