Manufacturing technology and application of cooling stave in blast furnace

The service life of blast furnace (BF) is depending on the cooling equipment of furnace body, cooling stave which is an important cooling equipment for BF has attracted more attention. In the current paper, the classification of BF cooling staves in China was introduced, cast iron stave, cast steel stave, copper stave, and copper-steel composite stave were used on different parts of furnace body. The manufacture of cooling staves was studied, evaporative pattern casting (EPC) was favored due to high automation and environmental protection. The strong combination between steel plate and copper plate of copper-steel composite stave could be ensured under high-speed oblique impact through explosive welding. High density and high thermal conductivity of copper stave could be obtained by efficient rolling technology. The performance and application of BF cooling stave were investigated, the advantages and disadvantages of the various cooling staves were analysed, the thermal resistance between the steel water pipe and the cast iron body accounted for about 80% of the total thermal resistance which would affect the cooling effect of cast iron stave. The significant cost advantage of copper-steel composite stave was found compared with copper stave, test results of copper-steel composite stave in a commercial BF showed that the cooling effect is equivalent to that of the copper stave. The suitable cooling stave in BF should be selected according to the characteristics of the various cooling staves, the heat transfer balance and the stability of the skull on the hot face must be ensured to protect the cooling stave.

Research on the Influence of Furnace Structure on Copper Cooling Stave Life

In this paper, a blast furnace gas flow distribution model with variable furnace structure was founded based on CFD (computational fluid dynamics) theory, and the gas velocity distribution near the surface of the copper staves in different areas of the BF is calculated under different conditions of variational structure parameters like Bosh angle, shaft angle, and the newly proposed “equivalent Bosh angle.” Based on the calculation, the influence rule of the BF structure on the service life of copper stave and the corresponding operation measures were obtained. The result shows that the increase of the Bosh angle and the decrease of the shaft angle will incur increasing of the gas flow velocity near the surface of the copper staves, which is harmful to the cooling stave life; the variation of the equivalent Bosh angle has a most significant influence on the cooling stave life, and the increase of the equivalent Bosh angle will cause a sharp increase of the gas flow velocity, which will damage the copper staves seriously; adopting long tuyeres and minishing the equivalent Bosh angle will reduce the washing action of the gas flow and ensure the stability of slag hanging to achieve a long service life of copper staves.