🔍 Key Concepts

• Difference between continuous blowdown and intermittent (bottom) blowdown in boiler operations • Where sludge tends to settle vs. where scum/foam tends to collect in a boiler • Why engineers control boiler water quality (salinity, dissolved solids, impurities) during steaming

💭 Think About

• Think about what needs to be removed constantly while the boiler is operating rather than occasionally or in short bursts. • Consider where a continuous flow is usually taken from in the boiler: the surface of the water, the bottom of the drum, or a vent line? • Which of these choices sounds like a task that must be done regularly to control water chemistry versus a task done only during start‑up or shutdown?

✅ Before You Answer

• Identify which two options deal with water chemistry control rather than air removal or start‑up procedures. • Recall that sludge tends to settle at the bottom, while dissolved solids/scum tend to concentrate near the water surface. • Ask yourself: does a continuous blow sound more suited to removing a slowly building impurity in solution, or a heavy deposit that accumulates in one spot?