🔍 Key Concepts

• Two-stage flash evaporator flow path – where seawater enters, how it moves through stages, and where it picks up heat • Function of distilling condensers – how they cool vapor and what happens to the incoming seawater passing through them • Feed heater purpose – why we preheat feed water before flashing

💭 Think About

• Trace the path of the cold seawater feed from when it first enters the system until it reaches the first flash chamber. Through which components does it flow, and what is happening to its temperature in each? • Ask yourself: in a two-stage plant, does the seawater only gain heat in one specific component, or does it pick up heat in more than one place before flashing? • Consider the main job of a distilling condenser. While it condenses vapor, what happens to the seawater that is used as cooling/condensing medium inside it?

✅ Before You Answer

• Make sure you understand that the distilling condensers often use incoming seawater as cooling water, which in turn raises the feed temperature before it becomes feed to the flash chambers. • Verify whether the seawater passes through both first and second stage condensers in series before entering any separate feed heater, if fitted. • Check which components in the choices actually transfer heat into the seawater feed (not just process distillate or brine).