🔍 Key Concepts

• complete vs incomplete combustion in a boiler furnace • effect of air supply on flame stability and heat release • how furnace heat output affects superheater and stack conditions

💭 Think About

• Think about what happens to the flame itself when there is not enough air to burn the fuel properly. How would it look and behave? • If less heat is released in the furnace because combustion is poor, what happens to the temperatures of gases going through the boiler and superheater? • Which choice is most directly tied to the immediate behavior of the flame in the furnace, not a secondary system like feedwater?

✅ Before You Answer

• Identify which options describe a direct effect on the flame versus indirect system effects. • Ask whether insufficient air would reasonably cause more heat or less heat to be transferred to the superheater and stack. • Eliminate any choice that mainly concerns feedwater usage, since air supply primarily affects combustion, not water input.