Special Consideration for Silica in High Pressure Boilers

Silica is an impurity commonly found in water. It is a compound of silicon and oxygen, and it can exist in both dissolved and undissolved forms. In general, silica is not a significant problem in low-pressure boilers. However, in high-pressure boilers, it can cause severe damage to the boiler components. In this section, we will discuss the reasons why silica requires special consideration in high-pressure boilers.

Silica Scaling

Silica scaling is a common problem in high-pressure boilers. When the water is heated, silica can precipitate out of the water and form hard, glass-like deposits on the boiler tubes and other components. These deposits can reduce the heat transfer efficiency of the boiler, leading to lower boiler efficiency and higher fuel consumption. In severe cases, the deposits can cause tube failures and other damage to the boiler.

Silica Carryover

Silica carryover is another problem associated with silica in high-pressure boilers. When the water is converted into steam, silica can be carried over into the steam. The silica particles can then deposit on the turbine blades and other downstream components. This can cause erosion and pitting of the turbine blades, leading to reduced turbine efficiency and increased maintenance costs.

Prevention and Control

To prevent silica scaling and carryover in high-pressure boilers, several measures can be taken, including:

- Maintaining the pH level of the water between 9 and 10.
- Using a good quality demineralization plant to remove dissolved silica from the water.
- Installing a silica analyzer to monitor the silica level in the water and adjust the chemical treatment accordingly.
- Using a silica dispersant to prevent silica from precipitating out of the water.
- Conducting regular boiler water analysis to detect any changes in the water chemistry.

Conclusion

Silica is a common impurity in water that can cause severe damage to high-pressure boilers. Silica scaling and carryover can reduce the efficiency of the boiler and downstream components, leading to increased maintenance costs and downtime. Therefore, it is essential to take special consideration of silica in high-pressure boilers and implement appropriate measures to prevent and control silica-related problems.

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