🔍 Key Concepts

• complete vs incomplete combustion in marine boilers • effect of air supply on smoke color and composition • relationship between fuel atomization/temperature and visible stack emissions

💭 Think About

• Think about what happens to fuel when there is more than enough air and the burn is very clean—what color is the smoke or vapor? • Which condition would most likely produce dark or sooty smoke rather than white? Eliminate those first. • How would low fuel temperature change atomization and burn quality—would that create white, black, or no visible smoke?

✅ Before You Answer

• Identify which options are associated with too much air versus too little air. • Decide which condition tends to produce black or dark smoke and rule it out for a white smoke question. • Consider whether water vapor/steam plays a role in the appearance of white stack emissions.