Refractories for Fluidized Bed 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, refractory bricks are better used in regular areas, and castables or plastics are used in irregular areas that are difficult to construct. The water-cooled air chamber is generally designed as an anti-wear structure with a single-layer lining. The material can be made of medium-quality wear-resistant plastic, and the air distribution plate is made of self-flowing corundum castable or corundum wear-resistant plastic.

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 corrosion resistance of the material.

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.

The combustion zone is above the feeding port, where the temperature of the flue gas is relatively high, generally above 850°C, and silicon carbide wear-resistant refractory castables or corundum wear-resistant castables can be used.

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

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.