SEARCH FOR RATIONAL DISTRIBUTION OF MATERIALS FOR THE BLAST FURNACE 5500 m3

Abstract

The purpose analytical study of the rational distribution of ore charging on the top of a blast furnace with a volume of 5500 m³ in order to identify a reserve for reducing coke consumption.
Methods. A mathematical model in which the heat transfer processes and iron reduction in the annular zones along the height of the charge column is described by a discrete system of material and heat balances in 12 vertical zones with charge temperature intervals from initial to 400°C and then every 100°C. Each of the vertical zones is characterized by its own specifics of the processes of heat and mass transfer, as well as the transition of materials from the solid phase to the liquid.
Results. The transition from the distribution of the ore charging O/С_rational to the distributions O/С_2-10 and O/С_2-9 leads to an equalization of the ore load RАZ-2-10 and a corresponding improvement in the use of gases. When О/С_2-9 is distributed, the peripheral region of the softening and melting zone is located in backpacks, and the intermediate region (RАZ-2-9) is shifted down and reduced in thickness. This creates favorable conditions for the use of gases. This reduces the temperature difference between the gas and the mixture in most of the radial annular zones and reduces the temperature of the top gas. Expected reduction in coke consumption: in the period from О/С_2-10 to the period from O/С_rational – 5 kg/t of pig iron; in the period from О/С_2-9 relative to the period from О/С_2-10 – 10 kg/t of pig iron; in total in the period from О/С_2-9 for the period from O/С_rational – 15 kg/t of pig iron; in total in the period with О/С_2-9 relative to the period with O/С_fact – 22 kg/t of pig iron.
Originality. The results of the study made it possible to quantitatively clarify the influence of the initial parameters on the final results (coke consumption, productivity), as well as to reveal the internal relationships of the processes in the furnace volume that affect the nature of the modes and the results of melting. Along with the clarification of the influence of the balance factors of coke economy, which determine the main value of the reduction in heat consumption, a significant impact on the consumption of coke of the nature of heat and mass transfer, phase transformations, gas mechanics and distribution of materials and gases in the furnace, connected by direct and feedback links with the consumption of coke, is quantitatively estimated.
Practical implications. The total reserve for reducing the consumption of coke due to the rationalization of the distribution of materials on the top according to the actual state is 22 kg/t of pig iron. Of these, 12 kg / t can only be realized by controlling the loading of the charge. Saving the next 10 kg/t of iron coke is associated with the need to influence the physical and mechanical properties of materials in order to achieve a more uniform distribution of materials in the most loaded radial annular zones.