The Challenges of Using Drinking Water as Boiler Feed Water in Industrial Applications

Boilers are a critical component in a wide range of industrial processes, providing heat and steam. However, the quality of the feed water used is crucial to ensure optimal performance and longevity of the boiler. While drinking water may seem like a suitable choice for feed water, it can lead to significant problems including scaling formation, corrosion, and heat transfer issues. This article explores the challenges associated with using drinking water in industrial boilers and highlights the importance of using demineralized (DM) or distilled water instead.

Scaling Formation: A Major Concern

Despite being considered a form of pure water, drinking water is not mineral-free. It contains trace amounts of dissolved solids, minerals, and salts that can precipitate and form a mineral deposit known as scale. This scale adheres to the inner surfaces of the boiler tubes, creating an insulating layer that obstructs the flow of water and restricts heat transfer. Consequently, the efficiency of the boiler decreases, leading to higher energy consumption and reduced performance.

Thermal Efficiency and Heat Transfer

The presence of scaling in boiler tubes creates a significant barrier to heat transfer. This scaling reduces the effective surface area available for heat exchange, causing the boiler to work harder to maintain its desired output. Over time, this can lead to thermal stress and potential boiler failure. The thermal resistance caused by scaling can also increase the risk of overheating, which can result in dangerous conditions such as boiler explosions.

Advantages of Demineralized or Distilled Water

To avoid the problems associated with scaling and maintain optimal boiler performance, it is recommended to use demineralized (DM) or distilled water as the feed water. These types of water are treated to remove all dissolved minerals and salts, resulting in a pure water solution that minimizes the risk of scaling. Using DM or distilled water ensures that the boiler operates efficiently and safely, reducing the likelihood of breaches or leaks.

Other Contaminants in Drinking Water

Drinking water, while cleaner than river water, still contains a few contaminants. It may contain trace amounts of chemicals such as potassium permanganate (KMnO4), alum, and chlorine, which are added to make it safe for consumption. Although these chemicals are effective in killing bacteria, they can pose problems in industrial boilers. For instance, KMnO4 and other chemical elements can lead to corrosion and pitting of the boiler internals, potentially causing leaks and reducing the operational life of the equipment.

Impact on Steam and Equipment

Moreover, scaling and dissolved chemicals in drinking water can be carried over to the steam produced by the boiler. This can damage steam pipes and turbines, leading to operational inefficiencies and increased maintenance costs. Additionally, the presence of these contaminants in the boiler drum can cause priming and foaming, which can lead to steam carryover. This not only affects the quality of the steam but can also cause damage to the steam distribution and handling systems.

Conclusion

While drinking water is an essential component of our daily lives, it is not ideal for use as boiler feed water in industrial settings. The need for clean, pure water free of dissolved solids and contaminants is critical to maintain the efficiency and safety of a boiler system. By opting for demineralized or distilled water, users can ensure optimal performance and longevity of their boilers, avoiding the risks associated with scaling, corrosion, and heat transfer issues.