🔍 Key Concepts

• Deaerating (DC) heater purpose – why it needs a constant source of low‑pressure steam • Difference between main steam, auxiliary steam pressures, and auxiliary exhaust steam in a typical marine plant • Normal vs. abnormal (startup/emergency) steam supplies to heaters

💭 Think About

• Ask yourself: Is the DC heater normally supplied from a high‑pressure live steam source, or from a lower‑energy source that is available whenever auxiliaries are running? • Which system on the list would most reasonably provide a continuous supply of steam without wasting high‑pressure energy? • In many traditional steam plants, what is done with exhaust steam from auxiliaries like pumps and turbines?

✅ Before You Answer

• Make sure you match the DC heater with a low‑pressure / heat‑recovery source rather than a primary propulsion steam source under normal conditions. • Eliminate options that would be inefficient for continuous heating duty in a large plant. • Think about what happens to turbine exhaust and other auxiliary exhausts in a conventional marine steam cycle.