🔍 Key Concepts

• How heat transfer in a boiler is affected by dirty water/steam generating tube surfaces • What happens to furnace temperature and gas flow when there is too much excess air • How fuel oil viscosity influences combustion quality and flame temperature

💭 Think About

• For each option, ask yourself: would this make the furnace gas temperature higher, lower, or unchanged? How would that affect the superheater outlet temperature? • Think about where the superheater is located in the gas path. If the superheater outlet temperature is high, what does that imply about the gas temperature passing over it? • Which of the listed conditions would cause inefficient heat transfer in the generating bank, forcing more heat to remain in the gases reaching the superheater?

✅ Before You Answer

• Verify which conditions would reduce heat transfer in the steam-generating tubes, causing hotter gases to continue toward the superheater. • Check whether excess air always increases, decreases, or can sometimes reduce furnace gas temperature. • Confirm how high fuel oil viscosity affects atomization, flame shape, and the resulting furnace gas temperature.