What is blowdown in the context of boiler operation?

Blowdown refers to the removal of sediments and impurities from boiler water. In boiler operation, water is continually evaporated to produce steam, resulting in the concentration of dissolved solids and contaminants in the boiler water. These impurities, if allowed to accumulate, can lead to scaling and corrosion within the boiler, which can compromise the efficiency and safety of the system.

To maintain water quality and protect the boiler components, a portion of the concentrated water, referred to as blowdown, is periodically discharged from the boiler. This process helps control the level of total dissolved solids (TDS) and removes sludge and other sediments that settle at the bottom of the boiler. Proper blowdown procedures are essential for optimizing boiler performance, reducing maintenance costs, and prolonging the life of the boiler.

The other options do not accurately describe blowdown: adding water to the boiler refers to makeup water, discharging steam relates to venting or safety mechanisms, and increasing boiler pressure pertains to operational settings rather than maintenance practices. Thus, the answer accurately captures the critical function of blowdown in boiler maintenance and operation.