🔍 Key Concepts

• Heavy fuel oil (HFO) settling tanks – purpose is to let water and sludge drop out before fuel enters service/booster systems • Pour point vs. ideal settling temperature – understand the difference between minimum temperature for flow and best temperature for separation • Effect of heating on circulation and disturbance – too much or too frequent heating can stir up settled contaminants

💭 Think About

• Ask yourself: Does continuous high heating help settling, or can it keep contaminants in suspension and possibly overheat the fuel? • Think about what happens inside the tank right after filling versus after it has been heated to the desired temperature – when is it best to keep the fuel as still as possible? • Which option best balances maintaining a suitable temperature with minimizing disturbance to settled sludge and water?

✅ Before You Answer

• Compare each option against the goal of a settling tank: maximum separation with minimum disturbance. • Check which choice respects both temperature control (not too cold, not overheated) and keeping the contents as undisturbed as practical once the correct temperature is reached. • Eliminate any option that suggests unnecessary or continuous agitation/heating that would keep solids and water from settling out.