Effect of supplying natural gas through flange holes on the operation of blast furnace tuyere with heat-insulating insert in the blast channel

Abstract

The distribution of natural gas, supplied into the blast channel of an air tuyere equipped with a heat-insulating insert, plays a positive role. On the one hand, it improves the mixing of natural gas with blast air and its combustion, and on the other hand, it reduces thermal stresses in the insert. The Ansys platform was used to perform mathematical simulation of gas dynamics, heat transfer, and combustion processes related to natural gas being supplied into the blast channel of a blast furnace tuyere through a series of holes in the flange. It has been shown that by supplying natural gas into the blast channel through the flange holes, it becomes possible to improve its combustion efficiency in the tuyere, leading to an increase in temperature and wind rate compared to the traditional method of supplying natural gas into the blast channel through a single tube via an inner sleeve. By using a model of the flange, containing only a manifold with a tube for supplying natural gas and its discharge through the holes, it was established that in order to minimize the non-uniformity in the natural gas supply distribution between the holes, the gas supply tube should be installed symmetrically relative to the manifold plugs, which in reality are formed by the tuyere cooling water supply and discharge tubes. It has been found that supplying natural gas through the flange holes leads to a decrease in thermal stresses in the insert by about 2 times compared to the traditional natural gas supply, which helps increase the durability of the insert. In this case, the resulting non-uniformity of supplying natural gas through the flange holes into the blast channel does not lead to a significant change in insert stresses.