Waste incinerators are widely used because of their good volume reduction effect, low cost and high degree of harmlessness. As the key lining material of waste incinerators, the selection of refractory brick materials is crucial.
There are various types of waste incinerators, including grate type, fluidized bed type, intermittent type, rotary type, etc. Different types of incinerators have different requirements for refractory materials due to their different structures and operating conditions.
1. Grate type incinerator: The biggest advantage of this type of furnace is that the technology is mature, the operation is stable and reliable, and the adaptability is wide. Most solid waste can be directly burned in the furnace without any pretreatment.
2. Fluidized bed incinerator: In the fluidized bed incinerator, the dense phase area at the bottom of the furnace is flushed by a large number of bed material particles and the vibration generated. The working layer refractory material is required to have higher wear resistance and strength, and at the same time has good resistance to the turbidity of corrosive gases in the bed layer. Wear-resistant castables with a refractoriness of more than 1100℃ and wear resistance that meets certain requirements are usually used.
3. Rotary incinerator: In a rotary kiln incinerator, the garbage in the kiln rotates and is constantly turned and thrown down with the rotary kiln, and the temperature of the refractory layer changes continuously. Therefore, materials with good wear resistance and thermal shock resistance are required. Generally, high-aluminum wear-resistant castables are selected, and high aluminum refractory bricks and SiC fire bricks can also be used.
2. Basis for the selection of refractory materials
The selection of refractory materials needs to comprehensively consider factors such as the atmosphere, temperature, slag and stress in the furnace.
1. Furnace atmosphere: The interior of the garbage incinerator is generally an oxidizing atmosphere. When selecting materials, it is often impossible to scientifically define the refractory materials. Targeted refractory materials should be selected according to the type of incinerated garbage and the atmosphere in the furnace.
2. Temperature: The maximum temperature of the garbage incinerator is about 1400℃. As the temperature continues to rise, the situation will also change. Especially for some high-aluminum refractory materials, their own refractory grade is not high, and they are easily affected by temperature and deteriorate.
3. Slag: A large amount of slag will appear during the use of the waste incinerator, and its main components include aluminum oxide, silicon oxide, iron oxide, etc., as well as some alkaline oxide materials. Compared with other neutral refractory materials, alkaline refractory bricks materials are more stable and will not fluctuate significantly.
4. Stress: The waste incinerator is mainly affected by several aspects of stress during use, including thermal stress caused by temperature gradient, mechanical stress at the contact part of the metal frame, composition change caused by oxidation corrosion, and loss of support caused by damage due to corrosion, etc.
