🔍 Key Concepts

• Scale formation in distilling plants (what causes it and where it forms) • Difference between flashing and boiling on a hot surface • How temperature and pressure affect mineral deposition (scale) on heat transfer surfaces

💭 Think About

• Which option best keeps minerals in solution and away from the hottest metal surfaces? • In a flash-type evaporator, where do you want the phase change (liquid to vapor) to occur to minimize scale on tubes and plates? • Think about whether high feed temperature or constant shell pressure alone will stop minerals from baking onto metal surfaces.

✅ Before You Answer

• Identify which choice describes vapor forming away from the heating surface instead of directly on it. • Ask: does this method reduce the time that hot brine is in contact with the heat transfer surfaces? • Eliminate any option that only talks about capacity or pressure without directly changing how and where the water turns into vapor.