A bottom blowdown is performed on a boiler to achieve what purpose?

The primary purpose of performing a bottom blowdown on a boiler is to discharge sludge and sediment. Over time, impurities in the boiler water, such as minerals, solid particles, and sediment, can settle at the bottom of the boiler. These deposits can cause various issues, including decreased efficiency, increased corrosion rates, and potential damage to the boiler internals.

By conducting a bottom blowdown, the water is drained from the bottom of the boiler, allowing these accumulated contaminants to be removed. This practice helps maintain water quality, ensures efficient heat transfer, and prolongs the lifespan of the boiler. Keeping the boiler clean and free from sludge is essential for safe and effective operation.

The other choices do not accurately represent the primary purpose of a bottom blowdown. For example, increasing boiler pressure is generally achieved through controlled water feed and heating rather than discharging water. Cooling down the boiler is not a goal of blowdown, as this process involves removing hot water rather than cooling it. Similarly, while maintaining clean water can have a positive effect on fuel efficiency indirectly, reducing fuel consumption is not the main objective of performing a bottom blowdown.