What is the primary purpose of a blowdown in boiler operation?

The primary purpose of a blowdown in boiler operation is to remove sludge and impurities from the boiler. Over time, as water is heated and turned into steam, various impurities such as dissolved solids and suspended particles can accumulate in the boiler water. These impurities can lead to problems such as scaling, corrosion, and foaming, which can impair the boiler's efficiency and safety.

Regular blowdown procedures help maintain water quality by discharging a portion of the boiler water, which is typically higher in concentration of these impurities, and replacing it with fresh water. This process not only keeps the boiler operating efficiently but also helps in prolonging the lifespan of the equipment by preventing damage caused by the accumulation of harmful substances.

The other options relate to boiler operation but do not capture the primary focus of blowdown, which is centered on water quality management and the removal of accumulated impurities.