Development of a heat-insulating insert in the blast channel of the blast furnace air tuyere using mathematical modeling

Abstract

Since the greatest heat losses in the air tuyere of the blast furnace fall on the blast channel, its thermal insulation is advisable. As the analysis shows, an effective way to reduce heat losses is ceramic inserts into the air tuyere duct. The efficiency of using the insert in the blast channel is shown by modeling the thermal and stressed state of the air tuyere using Excel, DEFORM-2D and Ansys Fluent programs. It was found that the air gap between the insert and the inner cup has the most significant effect on heat losses through the blast channel of the tuyere and the stresses in the insert. Modeling and industrial tests carried out on the DP–5 of PJSC Severstal of an experimental batch of tuyeres with a ceramic insert made it possible to clarify the parameters of the insert into the inner cup, which allows to reduce heat losses through the tuyere by 30–35 % and as a result to increase the blast temperature at the outlet of the tuyere by 10–15 °C. The manufacture of the insert taking into account the temperature coefficients of the linear expansion of the insert and tuyere materials and the treatment of its openings with a heatresistant sealant made it possible to increase the average durability of the insert, i.e. the working time of the tuyere before the beginning of the gradual destruction of the insert, determined by the change in heat losses, by 1.5 times. The design of the air tuyere with an insert into the blast channel is used in blast furnaces at PJSC Severstal.