In a two stage flash evaporator, operating...

🔍 Key Concepts

• Flash evaporator stages: how pressure and temperature change from one stage to the next to keep seawater boiling and flashing into vapor • Boiling point vs pressure: what happens to the boiling temperature of water when absolute pressure is reduced • Heat balance in multiple-effect/multi‑stage evaporators: how later stages use remaining heat from earlier stages

💭 Think About

• In a multi‑stage flash evaporator, does each successive stage usually run at a higher or lower pressure than the previous one? What does that do to the boiling temperature? • If hot brine from the first stage flows into the second stage without adding more heat, what must change in the second stage so that additional flashing (evaporation) can still occur? • Think about the trend stage‑to‑stage: as stage number increases, what generally happens to both temperature and absolute pressure in a distillation plant?

✅ Before You Answer

• Verify how the boiling temperature of water changes with absolute pressure (look at a steam or saturation table conceptually). • Confirm the direction of pressure gradient across the stages in a two‑stage flash evaporator (higher to lower, or lower to higher?). • Check which answer choice matches the typical trend for later stages in multi‑stage distillation: both in terms of temperature and absolute pressure.

In a two stage flash evaporator, operating conditions in the second stage, as compared to the first stage, are __________.

higher temperature and higher absolute pressure

higher temperature and lower absolute pressure

lower temperature and higher absolute pressure

lower temperature and lower absolute pressure

🔍 Key Concepts

💭 Think About

✅ Before You Answer