Top-burning hot blast furnace
The top-burning hot blast furnace can be roughly divided into three parts: the medium and low temperature area of the lower regenerator, the high temperature area of the upper regenerator, and the cone combustion chamber and burner area.
The furnace structure of the top-burning hot blast furnace can be mainly divided into two parts: the regenerator, the combustion chamber and the burner area, as shown in Figure 1. We have shared with you the selection and construction issues of refractory materials in the combustion chamber and the burner area in the previous article. The following is mainly the working principle and refractory material configuration of the regenerator of the hot blast furnace.
The regenerator is divided into three parts: the low temperature area, the medium temperature area and the high temperature area. Due to the different working environments during operation, the refractory material configuration used is also different.
Low temperature area
The operating temperature of the lower low temperature area of the regenerator is less than 900℃. Its main function is to bear the gravity load of the upper masonry and the strong convection heat exchange process at the initial stage of air supply. The requirements for refractory materials in this area are not too high, and products with good thermal shock resistance are required. Ordinary clay bricks are recommended.
Medium temperature zone
The temperature in the middle area of the regenerator often fluctuates between 800-1100℃. This area is called the transition zone between the high temperature area and the low temperature area. The application of its refractory bricks requires good high temperature creep properties. It is recommended to use low creep high alumina bricks or low creep clay bricks.
High temperature zone
In the upper part of the regenerator, due to the high temperature and alternating changes, the selected refractory materials are required to have good thermal stability. High alumina bricks are limited in use in this area due to their own creep properties and expansion characteristics.
Andalusite bricks are the best configuration choice in this area in terms of performance. They have the advantages of high refractoriness, high load softening temperature, good high temperature stability and good thermal shock resistance, but the price of andalusite bricks is relatively high.
In actual applications, there are more and more cases of using silica bricks in this area. Silica bricks have the advantages of good thermal expansion and high load softening point, but compared with andalusite bricks, they have poor anti-stripping performance and slightly lower heat storage capacity. If silica bricks are used in the working layer of the high-temperature zone at the top of the hot blast furnace, lightweight silica bricks suitable for the material of the working layer should be selected as the insulation layer.
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