The heating furnace is the key equipment of the rolling mill and the "heart" of the rolling mill. Therefore, the operating conditions of the heating furnace, the number of repairs, and the length of the service life have always received great attention from the rolling mill. Since the heating furnace is a long-term operation and a very critical thermal equipment, the rolling mills are very cautious in the selection of heating furnace materials, and the refractory companies are also cautious in the application of new materials to the heating furnace. Therefore, The technological progress of refractory materials for heating furnaces is relatively lagging behind that of refractory materials for steelmaking.
The refractory materials used for heating furnaces in China have successively experienced the periods of ordinary clay bricks and high alumina bricks, ramming materials and plastics, ordinary castables and high-performance castables. In recent years, a large number of refractory research and production units have conducted a lot of research on refractories for heating furnaces, which has made great progress in refractories for heating furnaces. The technical level of refractories for heating furnaces in China has approached the world's advanced level. . At present, refractories for heating furnaces in China are transitioning to the stage of intelligent quick-drying castables and quick-drying self-flowing castables.
Before the 1970s, the refractory materials for heating furnaces in our country mainly used clay bricks and high-alumina bricks, and the furnace structure was mainly a vault structure. Because the refractory materials used are low-grade materials, the high temperature performance is poor, and the furnace structure has defects, the service life of the heating furnace is very low. In addition, because the roof tiles are prone to loosening and falling off during the operation of the heating furnace, and local damage is too fast, the heating furnace is frequently repaired during the operation process, and the operation rate is low, resulting in poor operating stability of the heating furnace at the time. The thermal efficiency is low, and the heating quality of the billet is not satisfactory.
In the late 1980s, With the continuous advancement of monolithic refractory technology, a series of high-tech refractories such as low cement, ultra-low cement and cement-free castables came out in my country, and were used in various thermal kilns in the metallurgical industry. Get applied on. In the early 1990s, low-cement castables began to be applied to heating furnaces and achieved good results. After that, low cement, ultra low cement and cement-free castables quickly became widely used in heating furnaces.
A complete set of regenerative combustion device is composed of at least 2 burners, 2 regenerators, one or more gas reversing valves, fans and control system. The regenerator is filled in the regenerator: during normal operation When cold air or fuel enters the furnace for combustion through one side of the regenerator, the other side of the regenerator is used as a flue exhaust channel, and the high-temperature flue gas close to the temperature in the furnace passes through the regenerator. It is heated and cooled by itself, and when it is discharged from the cold end of the regenerator, the flue gas temperature can drop below 150°C.
A complete set of regenerative combustion device is composed of at least 2 burners, 2 regenerators, one or more gas reversing valves, fans and control system. The regenerator is filled in the regenerator: during normal operation When cold air or fuel enters the furnace for combustion through one side of the regenerator, the other side of the regenerator is used as a flue exhaust channel, and the high-temperature flue gas close to the temperature in the furnace passes through the regenerator. It is heated and cooled by itself, and when it is discharged from the cold end of the regenerator, the flue gas temperature can drop below 150°C.
Regenerator is the key material of regenerative heating furnace. It is the heat exchange medium of the regenerative heating furnace. They absorb the heat of the waste flue gas in the heating furnace and store it, and then use the stored heat to heat the air or fuel. In this way, not only the preheating temperature of the air and fuel is increased, It reduces the emission temperature of exhaust gas, saves energy, and also reduces CO2 and NOx emissions, which is beneficial to environmental protection.
In view of the special use conditions of the heat storage body, it is required that the heat storage body must have good heat storage and heat release capabilities. , The heat storage body must also have excellent thermal shock stability.
The heat storage body mainly has the following three forms: honeycomb body, heat storage ball and heat storage tube. In terms of molding methods, the honeycomb body and the heat storage tube are formed by the extrusion method, while the heat storage ball is divided into two types: manual molding and mechanical molding; in terms of materials, the honeycomb body is mainly composed of cordierite and mullite, and The heat bulb and heat storage tube are mainly high alumina and mullite.
