🔍 Key Concepts

• Boiler fuel systems on steam plants and how they handle different grades of fuel • Properties of diesel oil vs heavy fuel oil (HFO) (ignition quality, viscosity, need for heating) • Typical procedures for starting up (lighting off) and operating a steam plant

💭 Think About

• Think about which operating condition makes it hardest to use heavy fuel oil directly in the burners. • Ask yourself: At what time is proper preheating and conditioning of heavy fuel least available or not yet established? • Consider when operators want a cleaner-burning, easy-to-ignite fuel instead of thick, hard-to-ignite heavy fuel.

✅ Before You Answer

• Review when heavy fuel oil requires preheating and viscosity control before it can be burned safely. • Consider standard boiler light‑off procedures in marine steam plants: what fuel is commonly used first? • Eliminate any choices that describe conditions normally solved by adjusting firing rate/air supply rather than switching to diesel oil.