The hot blast stove is generally a thermal engineering device that periodically repeats heating and releasing heat. According to the current use of the hot blast stove, the requirements for the heat storage material of the hot blast stove are the following requirements
It has good volume stability, that is, it will not cause excessive expansion and contraction when the internal crystal phase structure changes during high temperature use, so that the thermal storage brick and the brick structure have good volume stability
The creep resistance of high-temperature load becomes better. The service time of the hot blast stove is more than 20 years. The load generated by the refractory's own weight is very large. Therefore, it is required that the refractory has good creep resistance at high temperature. The silicon brick has excellent high temperature creep properties, followed by high aluminum products close to mullite.
Has a high heat storage performance. The material is required to have high density and high specific heat capacity. The volume density of silicon brick is small, the heat storage capacity is poor, and when it is below 600 ℃, crystal transformation is easy to occur and the integrity of the material is destroyed, so the silicon brick is not suitable for use in the area below 600 ℃, in addition to the hot air furnace The oven should be heated or cooled slowly when the furnace is shut down to ensure the slow conversion of the quartz crystal phase without damaging the material.
Has better thermal conductivity. The high thermal conductivity allows the heat storage body to absorb and release heat with speed and efficiency during the heat switching cycle. The thermal conductivity of refractory materials is one of the most important physical properties of refractory materials. The thermal conductivity of materials is related to the chemical composition, mineral composition, density, microstructure and temperature of the material. In aluminum-silicon refractory materials, the thermal conductivity of the refractory material increases with the increase of Al2o3 content. Therefore, if the grid brick of the hot blast stove adopts high aluminum brick with high heat storage capacity, the air temperature of the hot blast stove can be greatly increased .
Low linear expansion coefficient. The coefficient of linear expansion refers to the performance of refractory materials with increasing volume and length with increasing temperature. Before 600 ℃, the linear expansion rate of silicon brick is very large, after 600 ℃ the linear expansion rate is almost unchanged.
