When the incinerated waste is a heterogeneous mixture of different compositions, its type, quantity and heat content are also very different. For this purpose the physical and chemical properties of the lining should be adapted to the requirements of different stages during operation. The working temperature of waste incinerators generally does not exceed 1400 ℃, but the complex working environment (such as gas erosion, wear and impact of waste on the furnace body during high temperature movement) requires high-quality refractory lining, and the demand is also constant Increase.
Generally, refractory materials are required to have the following characteristics: 1) High strength and good wear resistance to resist the abrasion of solid materials and erosion of hot air; 2) Good volume stability and acid resistance to resist the erosion of acidic substances in the furnace ; 3) Good thermal shock stability to resist the damage to materials caused by changes in furnace temperature; 4) Good corrosion resistance to avoid lining cracking caused by erosion; 5) Good high temperature strength and heat resistance, heat insulation .
The mechanical grate garbage incinerator can be divided into drying area, combustion area and burnout area according to the garbage combustion process, and can be divided into the feeding port area of the garbage pusher, the side wall of the grate, the front and rear arch areas and the slag discharge port according to the location; The temperature, mechanical strength and atmosphere of the furnace lining in these different regions are different, and corresponding refractory materials need to be selected according to their respective characteristics.
The garbage feeding port is located in the drying area of the incinerator. The temperature of the flue gas is generally 500-600 °C. It is easy to be thermally peeled due to the wear and tear of the garbage and the influence of moisture. Mullite castable with good strength; in the combustion zone of the incinerator, since the temperature is as high as about 1000 ℃, the side walls of the grate are also affected by garbage wear, slag adhesion, etc. Strong SiC hanging brick.
The upper side wall, furnace roof and other parts are subject to the thermal shock of the flame and the erosion of the combustion exhaust gas, and the smoke temperature here is higher, and the prefabricated bricks and castables of high alumina materials such as chrome corundum, SiC or mullite are mostly used. The temperature at the slag discharge port is relatively low (400-500°C), and high-alumina castables with higher strength are usually used. In a word, when the combustion temperature of the incinerator is less than 1200 °C, since the SiC products combined with siliceous binders form a dense and permanent inert layer surrounding the SiC grains in the application, materials with different SiC contents are suitable for its lining; At >1250℃, the melting and eroding atmosphere in the incinerator is relatively strong, and the refractory materials such as chrome corundum of high aluminum products are better than those of SiC.