Energy Saving and Environmental Protection of Refractory Materials for Blast Furnace Hot Blast Stove
The blast furnace hot blast stove is an energy efficient utilization device with both energy storage and heat exchange functions. It uses blast furnace gas as fuel and uses refractory materials as energy storage and heat exchange elements to provide hot air for high temperatures.
Every time the blast furnace hot air increases by 100°C, approximately Correspondingly reduce the coke ratio by 20kg/t molten iron. The hot blast stove is a typical regenerative heat exchanger. The checker bricks in the hot blast stove regenerator are the carriers for the heat exchange of the hot blast stove, and they play an important role in transferring the heat generated by burning coal gas to the blast furnace blast. The heat storage and heat release efficiency of checker bricks directly affect the hot blast temperature and the thermal efficiency of the hot blast stove.
Without changing the area and material of the checker bricks, the effect of the thermal conductivity of the material itself on the heat transfer efficiency of the hot blast stove was studied. The result is: to improve the thermal conductivity of the checker bricks and significantly improve the heat exchange efficiency of the hot blast stove.
When the thermal conductivity of the silica brick is increased from 1.8W/(m·K) to 2.3W/(m·K), the burning period of the hot blast stove is shortened by 8.2%. The hot blast stove is divided into several areas such as high, medium, low temperature and high and low temperature exchange. According to the different characteristics of refractory materials, the combination of silica brick, high alumina brick and clay brick is generally selected in our country.
The high temperature zone (800~1500°C), including the vault and the upper part of the checker brick, is stable as a high temperature zone, and is mainly made of silica bricks. Because the high temperature performance of silica brick is stable, the true density is small, the quality can be reduced, and it has the characteristics of high load softening temperature, low high temperature creep rate, and large thermal conductivity. It is commonly used in hot blast stove high temperature area. ℃) Low-creep high-alumina bricks or andalusite bricks are generally selected; the low temperature zone (350~900℃) is in the lower part of the combustion chamber and the regenerator, mainly made of clay bricks.
