Early models of the flash-type evaporators used a separate shell-and-tube heat exchanger as the air ejector condenser. More recent models use a combined air ejector condenser with the __________.

Correct Answer: Option B — salt water feed heater

Modern flash evaporator designs integrate the air ejector condenser with the salt water feed heater. This configuration improves thermal efficiency by utilizing the latent heat of the non-condensable vapor mixture to preheat the incoming seawater feed before it enters the main heating section of the evaporator.