What is meant by "fouling" in the context of boiler operations?

Fouling refers specifically to the accumulation of deposits and contaminants on the heat transfer surfaces of a boiler. This buildup can arise from various sources, such as minerals in the water, oil, or debris, and it creates a layer that acts as an insulator. As a result, the efficiency of heat transfer decreases, requiring more energy to achieve the same output, which can lead to increased operational costs and potential damage or failure of boiler components over time. Maintaining clean heat transfer surfaces is crucial for optimal boiler performance, making understanding fouling an essential aspect of boiler operation and maintenance.