🔍 Key Concepts

• Identify what type of desalination/distilling unit the illustration shows (flash-type evaporator vs boiling-type still). • Trace the flow of seawater/feed water through the labeled sections and note where it first encounters vacuum conditions inside the shell. • Distinguish between the heating/condensing sections (tube bundles) and the open shell space where evaporation/flash occurs.

💭 Think About

• Look at where the hot feed water leaves the heater/heat-exchanger tubes and enters the open shell area: what physical process happens when hot water enters a low-pressure (vacuum) chamber? • Compare the location of labels E, F, and G: which one clearly shows the tube bundles, which shows free vapor space, and which is the lowest part where heavier deposits would settle? • Ask yourself: is scale more likely to build up in the lowest collection space, on heat-transfer surfaces, or in a mid‑shell vapor region like the one marked G?

✅ Before You Answer

• Verify which label points to the actual tube bundles or jackets carrying heating/condensing fluid (jacket water or steam). • Confirm that section G is an open chamber region, not a tube, pump, or solid surface, and consider what phase (liquid or vapor) would primarily occupy it during operation. • Double‑check that label E is at the very bottom of the shell, where brine and solids would logically collect, before you decide whether scale accumulation happens at G or elsewhere.