1. Composition of boiler scale
The composition of feed water and boiler water is different, and the specific conditions for scale formation are different, which makes the composition of boiler scale different. The more common ones are the following:
1. Carbonate scale: Carbonate scale is mostly generated in the parts of the boiler with relatively low temperature, with calcium and magnesium as the main components. Generally, hot water boilers are mostly carbonate scale.
2. Silicon salt pollution: The silica content in silica scale can reach more than 20%, which is easy to form in the parts with the highest boiler temperature.
3. Sulfate scale: Sulfate scale is harder than carbonate scale and is not easy to clean. The main component of sulfate scale is calcium sulfate. It reaches more than 50%, and it is formed on the evaporation surface with the highest temperature and the greatest evaporation intensity in the boiler.
4. Mixed scale: Mixed scale is a mixture of the above-mentioned scales, with mixed colors and multiple layers, and is usually formed at the junction of high and low temperature zones in the boiler.
5. Oily scale: The composition of oily scale is very complex, with a high oil content, and is usually generated at the highest temperature part of the forging furnace.
2. Hazards of boiler scale
Boiler water systems are widely used in industrial production. If the boiler scale is not cleaned properly, it will seriously corrode the boiler equipment and reduce production efficiency.
1. Corrosion of equipment: Boiler scale will corrode equipment, affect safe production, and shorten the service life of the boiler.
2. Salt accumulation: Carbonate scale can reduce the thermal efficiency of the boiler. When the salt accumulation is severe, it can cause the tube wall to burst, which directly endangers the safe and economic operation of the boiler.
3. Scaling: Boiler scale reduces the heat transfer capacity of the boiler tube, causing the tube wall to overheat and reduce strength, and even deformation or bursting accidents.
3. Treatment methods for boiler scale
In order to make the boiler system operate in the most optimized state, the boiler water system must be treated with special chemicals regularly. The cleaning of the boiler is divided into two parts. One part is the cleaning of the scale and rust of the boiler convection tube, superheater tube, air heater, and water-cooled wall tube; the other part is the cleaning of the outside of the tube, that is, the cleaning of the boiler furnace.
1. Chemical cleaning: Add various chemical cleaning agents to clean and disperse the floating rust, scale, and oil in the system and restore it to a clean metal surface.
2. Daily maintenance: Add boiler scale inhibitors to prevent metal rust and prevent calcium and magnesium ion crystal accumulation.
