Improvement of technological requirements for distribution of burden materials and gas flow in the operation of blast furnaces with low silicon content in pig iron and assessment of their implementation on modern blast furnaces

Abstract

Reducing the silicon content in pig iron is one of the most effective ways to reduce fuel and reductant consumption in the blast furnace process. The challenges of smelting pig iron with low silicon content are associated with high ore burden and low solid fuel consumption, resulting in a reduction in the thickness of "coke windows" with a corresponding deterioration of the gas permeability of the burden column and a decrease in the stability of the melt descent. Additionally, there is a decrease in the thermal level of the cohesive zone, shifting its boundaries upwards in the furnace and increasing its overall size. Moreover, reducing the amount of solid fuel in the burden and increasing the requirements for the quality and stability of the characteristics of iron ore materials can lead to a reduction in the heat reserve in the upper part of the furnace. Research Objective: To improve technological requirements for the distribution of burden materials and gas flow as fundamental principles that determine the parameters of the charging regime of the blast furnace under specific conditions, taking into account the peculiarities and technological constraints of blast smelting with low silicon content in pig iron. The study involves the consolidation of results from analytical and laboratory research, as well as the industrial experience of smelting low-silicon pig iron under production conditions. Technological requirements have been developed for the distribution of ore burden, ensuring stable axial movement of the blast furnace under specific melting conditions, the distribution of iron ore components of the burden, based on the tasks of ensuring the stability of the sinter layer and preserving the lining, as well as the distribution of various substitutes for iron ore burden materials and coke, taking into account their properties and technological characteristics. Recommended parameters for the "soft" preventive flushing of blast furnaces are provided to ensure the necessary gas permeability of the burden column, the diffusion capacity of the coke layer, and the support of a stable axial distribution of the gas flow. An assessment of the possibilities of implementing improved technological requirements for the distribution of burden and gas flow under conditions of smelting low-silicon pig iron in modern blast furnaces has been carried out.