What Are the Refractory Materials Used in Waste Incinerators?

The application of refractory and wear-resistant materials for circulating fluidized bed waste incinerators is mainly divided into the following areas: air chamber, dense-phase area at the lower part of the furnace, combustion area, feeding port, high-temperature cyclone separator, and return pipe, etc., different areas Reasonable refractory and wear-resistant materials should be selected according to the atmospheric conditions. Generally speaking, it is better to use refractory bricks for regular areas, and castables or plastics for irregular areas that are difficult to construct.

For fluidized bed waste incinerators, the density difference between the bed material and the waste is relatively large, and the waste is mainly burned in the dilute phase area, while the temperature in the dense phase area is relatively low, and the wear is relatively strong. Generally, corundum castables or wear-resistant plastics are used. Oxygen-deficient combustion here has a strongly reducing atmosphere, and the Fe₂O₃ content of the material should be strictly controlled to improve the material’s ability to resist CO erosion.

1. Garbage discharge port and coal discharge port

The garbage discharge port and the coal discharge port are located at the junction of the dense phase area and the dilute phase area. These two parts are easy to wear, and more wear-resistant corundum-bonded silicon carbide castables or mixed mullite and corundum castables can be used.

2. Burning zone

That is, above the feeding port, where the flue gas temperature is relatively high, generally above 850°C, silicon carbide wear-resistant refractory castable or corundum wear-resistant castable can be used.

3. Furnace outlet and separator inlet

This area is easy to wear parts, especially the separator inlet, high-strength wear-resistant castables, or silicon carbide bricks can be used. Since this area is an irregular area, construction methods, and experience are particularly important.

4. Return pipe

The return pipe is also a key component of the circulating fluidized bed. It is generally designed as an anti-wear structure with multi-layer lining. The material is high-strength wear-resistant refractory castables, corundum wear-resistant bricks, etc., and its specific construction method is determined according to the size of the pipe diameter.

Garbage contains a large amount of acidic substances, such as chlorides, sulfates, etc. These substances will chemically react with refractory materials at high temperatures, causing them to lose their stability. Therefore, waste incinerators usually use alkaline refractory castables, which can withstand chemical reactions and mechanical shocks at high temperatures, and ensure long-term stable operation.

Commonly used alkaline refractory castables include high-alumina castables, magnesium-aluminum castables, and magnesium-calcium castables. These castables have good corrosion resistance and high-temperature stability, can effectively prevent the erosion and bonding of slag, and prolong the service life of refractory materials.

Among them, high alumina castable is a commonly used basic refractory material, its main components are alumina and aluminum silicate, which can resist chemical reactions and mechanical impact at high temperatures, and has good thermal stability and wear resistance sex. In addition, magnesium-aluminum castables and magnesium-calcium castables also have similar performance characteristics, but the price is relatively high.

In short, the garbage incinerator is an important environmental protection equipment, which can treat garbage at high temperatures and reduce the harm of solid waste to the environment. However, in the high-temperature environment of waste incinerators, refractory materials are easily eroded and damaged. Therefore, it is very important to choose a suitable refractory castable. When selecting refractory materials, it is necessary to conduct a comprehensive evaluation and selection according to specific service conditions and requirements.