Design parameters optimization for blast furnace ironmaking process with exergy efficiency maximization

Based on material and energy balances, a design-parameter optimization model for the blast furnace ironmaking process with an exergy efficiency maximization objective is established. A total of 13 optimization variables (dosages of iron ores, coke ratio, coal ratio, blast volume, etc.) are optimized using the practical production data from a blast furnace in an integrated steelworks, considering 21 constraint conditions. The maximum exergy efficiency and the corresponding optimal material dosages are obtained. The influences of the main parameters on exergy efficiency are analyzed, and the relationships among parameters are studied. The results show that the maximum exergy efficiency of the blast furnace after optimization is 79.28%, which is improved by 2.12% compared with the original production plan. Appropriately decreasing the dosage of sinter ore and synchronously increasing the dosages of pellet ore and lump ore effectively improve the exergy efficiency. To improve exergy efficiency, the dosage of sinter ore should be in the range of 957–1228 kg/t and close to 986 kg/t; the dosage of pellet ore should be in the range of 217–508 kg/t and close to 457 kg/t; and the dosage of lump ore should be increased. Decreasing the coke ratio, increasing the coal ratio, and reducing the blast volume can also improve the exergy efficiency.