Effect of natural gas flow rate and temperature on the processes occurring in a blast furnace tuyere with heat-insulating insert in blast channel

Abstract

The purpose of this work was to analyze the effect of a heat-insulating insert, as well as the flow rate and temperature of natural gas on the processes occurring in blast channel of an air tuyere. The paper analyzes the results of industrial and numerical experiments obtained by different researchers on the use of various methods for increasing the completeness of combustion reaction within the air tuyere of natural gas (NG) fed into it: increase of NG flow rate; increase of NG temperature; the use of heat-insulating inserts installed in the inner glass of the air tuyere. Using the Ansys Fluent software complex, the effect of a heat-insulating insert and increase in NG flow rate on the temperature and composition of gases leaving the tuyere of blast furnace no. 5 of PJSC Severstal was studied. It was found that with an increase in NG flow rate from 0.283 to 0.328 kg/s, the temperature of the gas medium at the tuyere outlet decreases by 6 °С for the variant without an insert and increases by 3 °С for the variant with it. When studying the effect of a heat-insulating insert and increase in NG temperature (in different combinations) on the processes occurring in a tuyere, it was found that temperature of the gaseous medium at the tuyere outlet in case of using a heat-insulating insert without NG heating is slightly higher than when NG is heated to 200 °С without inserts. However, the effect of NG heating in the presence of an insert is significantly higher than without it – there is mutual amplification of two factors influencing the completeness of NG combustion within the tuyere, accompanied by protection of the tuyere inner nozzle from burnout.